Aggregate Planning in Decentralized Organizations

Chapter 8Aggregate Planning in the Supply ChainTrue/False1. The goal of aggregate planning is to satisfy demand in a way that minimizesprofit.Answer: FalseDifficulty: Easy2. Aggregate planning is a process by which a company determines levels ofcapacity, production, subcontracting, inventory, stockouts, and even pricing overa specified time horizon.Answer: TrueDifficulty: Moderate3. Aggregate planning solves problems involving aggregate decisions rather thanstock keeping unit (SKU) level decisions.Answer: TrueDifficulty: Easy4. Traditionally, much of aggregate planning is focused within an enterprise andmay not always be seen as a part of supply chain management.Answer: TrueDifficulty: Moderate5. Aggregate planning is an important supply chain issue because, to be effective, itrequires inputs from throughout the supply chain, but its results have little impact on the supply chain.Answer: FalseDifficulty: Moderate6. Short-term production serves as a broad blueprint for operations and establishesthe parameters within which aggregate planning decisions are made.Answer: FalseDifficulty: Easy7. The aggregate planning problem is concerned with determining the productionlevel, inventory level, and capacity level (internal and outsourced) for each period that maximizes the firm’s profit over the planning horizon.Answer: TrueDifficulty: Moderate8. To create an aggregate plan, a company must specify the planning horizon forthe plan and the duration of each period within the planning horizon.Answer: TrueDifficulty: Easy9. A planning horizon is usually between three and five years.Answer: FalseDifficulty: Moderate10. A poor aggregate plan can result in improved sales and profits if the availableinventory and capacity are unable to meet demand.Answer: FalseDifficulty: Easy11. A poor aggregate plan may result in a large amount of excess inventory andcapacity, thereby raising costs.Answer: TrueDifficulty: Moderate12. The aggregate planner must make a trade-off between capacity, inventory, andbacklog costs.Answer: TrueDifficulty: Moderate13. An aggregate plan that increases one cost typically results in the increase of theother two.Answer: FalseDifficulty: Moderate14. The time flexible strategy is where the production rate is synchronized with thedemand rate by varying machine capacity or hiring and laying off employees asthe demand rate varies.Answer: FalseDifficulty: Hard15. The time flexible strategy is where workforce (capacity) is kept stable but thenumber of hours worked is varied over time in an effort to synchronize production with demand.Answer: TrueDifficulty: Moderate16. The mixed strategy is where a stable machine capacity and workforce aremaintained with a constant output rate with inventory levels fluctuating over time.Answer: FalseDifficulty: Hard17. Most strategies that an aggregate planner actually uses are in combination, andare referred to as mixed strategies.Answer: TrueDifficulty: Easy18. A highly effective tool for a company to use when it tries to maximize profits whilebeing subjected to a series of constraints is aggregate programming.Answer: FalseDifficulty: Moderate19. To improve the quality of these aggregate plans, forecast errors must be takeninto account when formulating aggregate plans.Answer: TrueDifficulty: Moderate20. Forecasting errors are dealt with in aggregate plans using either safety backlogor safety capacity.Answer: FalseDifficulty: Moderate21. Safety inventory is defined as inventory held to satisfy demand that is higher thanforecasted.Answer: TrueDifficulty: Easy22. Safety capacity is defined as capacity used to satisfy demand that is lower thanforecasted.Answer: FalseDifficulty: Easy23. Companies should work with downstream partners to produce forecasts and withupstream partners to determine constraints when doing aggregate planning.Answer: TrueDifficulty: Easy24. The aggregate plan should be viewed primarily as an in-house tool that does notneed to be communicated to supply chain partners.Answer: FalseDifficulty: Easy25. Given that forecasts are always wrong to some degree, the aggregate planneeds to have some flexibility built into it if it is to be useful.Answer: TrueDifficulty: Moderate26. A manager should perform sensitivity analysis on the inputs into an aggregateplan to choose the best solution for the range of possibilities that could occur.Answer: TrueDifficulty: Moderate27. As inputs into the aggregate plan change, managers do not need to makechanges to the aggregate plan.Answer: FalseDifficulty: Easy28. As capacity utilization increases, it becomes less important to perform aggregateplanning.Answer: FalseDifficulty: ModerateMultiple Choice1. The process by which a company determines levels of capacity, production,subcontracting, inventory, stockouts, and even pricing over a specified timehorizon isa. aggregate planning.b. detail planning.c. inventory planning.d. sales planning.e. all of the aboveAnswer: aDifficulty: Moderate2. The goal of aggregate planning is toa. dissatisfy customers in a way that maximizes profit.b. dissatisfy customers in a way that minimizes profit.c. satisfy demand in a way that maximizes profit.d. satisfy demand in a way that minimizes profit.e. none of the aboveAnswer: cDifficulty: Easy3. Aggregate planning solves problems involvinga. aggregate decisions and stock keeping unit (SKU) level decisions.b. aggregate decisions or stock keeping unit (SKU) level decisions.c. aggregate decisions rather than stock keeping unit (SKU) level decisions.d. stock keeping unit (SKU) level decisions rather than aggregate decisions.e. b and c onlyAnswer: cDifficulty: Easy4. Aggregate planning, to be effective, requires inputs froma. all customers.b. all departments.c. all suppliers.d. throughout the supply chain.e. throughout the company.Answer: dDifficulty: Moderate5. Much of aggregate planning has traditionally been focuseda. on short-term production scheduling.b. on customer relationship management.c. within an enterprise.d. beyond enterprise boundaries.e. all of the aboveAnswer: cDifficulty: Moderate6. Which of the following are not operational parameters the aggregate planner isconcerned with?a. production rateb. workforcec. overtimed. backorderse. inventory on handAnswer: dDifficulty: Moderate7. The operational parameter concerned with the number of units completed perunit time (such as per week or per month) isa. production rate.b. workforce.c. overtime.d. backlog.e. inventory on hand.Answer: aDifficulty: Easy8. The operational parameter concerned with the number of workers/units ofcapacity needed for production isa. production rate.b. workforce.c. overtime.d. backlog.e. inventory on hand.Answer: bDifficulty: Easy9. The operational parameter concerned with the amount of overtime productionplanned isa. production rate.b. workforce.c. overtime.d. backlog.e. inventory on hand.Answer: cDifficulty: Easy10. The operational parameter concerned with demand not satisfied in the period inwhich it arises, but carried over to future periods isa. production rate.b. workforce.c. overtime.d. backlog.e. inventory on hand.Answer: dDifficulty: Easy11. The operational parameter concerned with the planned inventory carried over thevarious periods in the planning horizon isa. production rate.b. workforce.c. overtime.d. backlog.e. inventory on hand.Answer: eDifficulty: Easy12. The operational parameter concerned with the number of units of machinecapacity needed for production isa. machine capacity level.b. subcontracting.c. overtime.d. backlog.e. inventory on hand.Answer: aDifficulty: Easy13. The operational parameter concerned with the subcontracted capacity requiredover the planning horizon isa. machine capacity level.b. subcontracting.c. overtime.d. backlog.e. inventory on hand.Answer: cDifficulty: Easy14. The aggregate plana. serves as a broad blueprint for operations.b. establishes the parameters within which short-term production anddistribution decisions are made.c. allows the supply chain to alter capacity allocations and change supplycontracts.d. all of the abovee. b and c onlyAnswer: dDifficulty: Moderate15. Aggregate planning is concerned with determininga. the production level, sales level, and capacity for each period.b. the demand level, inventory level, and capacity for each period.c. the production level, inventory level, and capacity for each period.d. the production level, staffing level, and capacity for each period.e. none of the aboveAnswer: cDifficulty: Moderate16. To create an aggregate plan, a company must specifya. the planning horizon for the plan.b. the duration of each period within the planning horizon.c. key information required.d. all of the abovee. a and b onlyAnswer: dDifficulty: Moderate17. The planning horizon isa. the time period over which the aggregate plan is to produce a solution.b. the duration of each time period in the aggregate plan.c. the length of time required to produce the aggregate plan.d. the solution to the aggregate plan.e. none of the aboveAnswer: aDifficulty: Easy18. The length of the planning horizon is usually betweena. one and three months.b. three and eighteen months.c. one and three years.d. three and five years.e. none of the aboveAnswer: bDifficulty: Moderate19. Which of the following is not information needed by the aggregate planner?a. demand forecast for each period in the planning horizonb. production costsc. labor costsd. cost of subcontracting productione. cost of changing the demand forecastAnswer: eDifficulty: Moderate20. The cost of changing capacity includes thea. cost of adding machine capacity.b. cost of reducing machine capacity.c. cost of hiring workforce.d. cost of laying off workforce.e. all of the aboveAnswer: eDifficulty: Easy21. Which of the following is not a cost of changing capacity?a. cost of adding machine capacityb. cost of hiring workforcec. cost of laying off workforced. cost of overtimee. cost of reducing machine capacityAnswer: dDifficulty: Moderate22. Which of the following is not a constraint the aggregate planner needs toconsider?a. limits on stockouts and backlogsb. limits on overtimec. limits on sales commissionsd. limits on layoffse. limits on capital availableAnswer: cDifficulty: Moderate23. A poor aggregate plan can result ina. appropriate inventory levels.b. efficient use of capacity.c. better sales and lost profits.d. lost sales and lost profits.e. lost sales and better profits.Answer: dDifficulty: Hard24. The fundamental trade-offs available to an aggregate planner are betweena. capability, inventory, and backlog costs.b. capability, inventory, and sales costs.c. capacity, inventory, and backlog costs.d. capacity, inventory, and sales costs.e. none of the aboveAnswer: cDifficulty: Easy25. Which of the following is not a distinct aggregate planning strategy for achievingbalance between capacity, inventory, and backlog costs?a. adjustable strategyb. Chase strategyc. level strategyd. mixed strategye. time flexible strategyAnswer: aDifficulty: Easy26. The strategy where the production rate is synchronized with the demand rate byvarying machine capacity or hiring and laying off employees as the demand rate varies is thea. adjustable strategy.b. Chase strategy.c. level strategy.d. mixed strategy.e. time flexible strategy.Answer: bDifficulty: Moderate27. The strategy where workforce (capacity) is kept stable but the number of hoursworked is varied over time in an effort to synchronize production with demand is thea. adjustable strategy.b. Chase strategy.c. level strategy.d. mixed strategy.e. time flexible strategy.Answer: eDifficulty: Moderate28. The strategy where a stable machine capacity and workforce are maintained witha constant output rate, with inventory levels fluctuating over time, is thea. adjustable strategy.b. Chase strategy.c. level strategy.d. mixed strategy.e. time flexible strategy.Answer: cDifficulty: Hard29. Most strategies that an aggregate planner actually uses are in combination andare referred to as thea. adjustable strategy.b. Chase strategy.c. level strategy.d. mixed strategy.e. time flexible strategy.Answer: dDifficulty: Easy30. A highly effective tool for a company to use when it tries to maximize profits whilebeing subjected to a series of constraints isa. aggregate programming.b. distribution programming.c. production programming.d. linear programming.e. manufacturing programming.Answer: dDifficulty: Moderate31. When formulating aggregate plans,a. forecast errors have no impact.b. forecast errors must be taken into account.c. forecast accuracy is assumed.d. forecast accuracy is not a factor.e. none of the aboveAnswer: bDifficulty: Moderate32. Forecasting errors are dealt with usinga. safety backlog.b. safety capacity.c. safety inventory.d. all of the abovee. b and c onlyAnswer: eDifficulty: Moderate33. Inventory held to satisfy demand that is higher than forecasted isa. safety backlog.b. safety capacity.c. safety inventory.d. safety sales.e. safety workforce.Answer: cDifficulty: Easy34. Capacity used to satisfy demand that is higher than forecasted isa. safety backlog.b. safety capacity.c. safety inventory.d. safety sales.e. safety workforce.Answer: bDifficulty: Easy35. Which of the following is an approach a company can use to create a buffer forforecast error using safety inventory?a. overtimeb. carry extra workforce permanentlyc. build and carry extra inventoriesd. subcontractinge. purchase capacity or product from an open or spot marketAnswer: aDifficulty: Easy36. Which of the following is not an approach a company can use to create a bufferfor forecast error using safety capacity?a. overtimeb. carry extra workforce permanentlyc. build and carry extra inventoriesd. subcontractinge. purchase capacity or product from an open or spot marketAnswer: cDifficulty: Easy37. Aggregate planning should consider information froma. only the enterprise as its breadth of scope.b. downstream partners to produce forecasts.c. upstream partners to determine constraints.d. all of the abovee. b and c onlyAnswer: dDifficulty: Easy38. The quality of the aggregate plan can be improved by using information froma. only the local firm.b. only downstream partners.c. only upstream partners.d. all parts of the supply chain.e. none of the aboveAnswer: bDifficulty: Moderate39. The aggregate plan should be communicated toa. only the local firm.b. only downstream partners.c. only upstream partners.d. all supply chain partners who will be affected by it.e. none of the aboveAnswer: cDifficulty: Moderate40. The aggregate plan needs toa. be a final product because changes are disruptive to the supply chain.b. be considered fixed because forecasts are usually accurate.c. have some flexibility built into it because forecasts are always wrong.d. have some flexibility built into it because forecasts are usually right.e. none of the aboveAnswer: cDifficulty: Moderate41. How frequently should the aggregate plan be rerun?a. weeklyb. monthlyc. every 3 to 8 monthsd. as inputs to the aggregate plan changee. neverAnswer: dDifficulty: Hard42. As capacity utilization increases,a. it becomes less important to perform aggregate planning.b. it becomes more important to perform aggregate planning.c. it does not affect the importance of performing aggregate planning.d. it lessens the importance of aggregate planning.e. none of the aboveAnswer: bDifficulty: ModerateEssay/Problems1. Discuss the primary objective and operational parameters of aggregate planning.Answer: The goal of aggregate planning is to satisfy demand in a way thatmaximizes profit. Aggregate planning is a process by which a companydetermines levels of capacity, production, subcontracting, inventory, stockouts,and even pricing over a specified time horizon. The aggregate planner’s mainobjective is to identify the following operational parameters over the specifiedtime horizon:• Production rate: the number of units completed per unit time (such as per week or per month).• Workforce: the number of workers/units of capacity needed for production.• Overtime: the amount of overtime production planned.• Machine capacity level: the number of units of machine capacity needed forproduction.• Subcontracting: the subcontracted capacity required over the planning horizon.• Backlog: demand not satisfied in the period in which it arises but carried over to future periods.• Inventory on hand: the planned inventory carried over the various periods in the planning horizon.The aggregate plan serves as a broad blueprint for operations and establishesthe parameters within which short-term production and distribution decisions are made. The aggregate plan allows the supply chain to alter capacity allocationsand change supply contracts.Difficulty: Moderate2. Discuss the information required for aggregate planning.Answer: An aggregate planner requires the following information:• Demand forecast F t for each Period t in the planning horizon that extends over T periods• Production cos ts• Labor costs, regular time ($/hour), and overtime costs ($/hour)• Cost of subcontracting production ($/unit or $/hour)• Cost of changing capacity; specifically, cost of hiring/laying off workforce($/worker) and cost of adding or reducing machine capacity ($/machine)• Labor/machine hours required per unit• Inventory holding cost ($/unit/period)• Stockout or backlog cost ($/unit/period)• Constraints:• Limits on overtime• Limits on layoffs• Limits on capital available• Limits on stockouts and ba cklogs• Constraints from suppliers to the enterpriseThis information is used to create an aggregate plan that in turn helps a company make the following determinations:• Production quantity from regular time, overtime, and subcontracted time:used to determine number of workers and supplier purchase levels.• Inventory held: used to determine how much warehouse space andworking capital is needed.• Backlog/stockout quantity: used to determine what the customer servicelevels will be.• Workforce hired/laid off: used to determine any labor issues that will beencountered.• Machine capacity increase/decrease: used to determine if newproduction equipment needs to be purchased or idled.The quality of an aggregate plan has a significant impact on the profitability of a firm. A poor aggregate plan can result in lost sales and lost profits if the available inventory and capacity are unable to meet demand. A poor aggregate plan mayalso result in a large amount of excess inventory and capacity, thereby raisingcosts. Therefore, aggregate planning is a very important tool in helping a supply chain maximize profitability.Difficulty: Hard3. Explain the basic strategies that an aggregate planner has available to balancethe various costs and meet demand.Answer: There are essentially three distinct aggregate planning strategies forachieving balance between these costs. These strategies involve trade-offsbetween capital investment, workforce size, work hours, inventory, andbacklogs/lost sales. Most strategies that a planner actually uses are acombination of these three and are referred to as mixed strategies. The threestrategies are as follows:1. Chase strategy—using capacity as the lever: With this strategy, the productionrate is synchronized with the demand rate by varying machine capacity or hiring and laying off employees as the demand rate varies. In practice, achieving thissynchronization can be very problematic because of the difficulty in varyingcapacity and workforce on short notice. This strategy can be expensive toimplement if the cost of varying machine or labor capacity over time is high. Itcan also have a significant negative impact on the morale of the workforce. TheChase strategy results in low levels of inventory in the supply chain and highlevels of change in capacity and workforce. It should be used when the cost ofcarrying inventory is very expensive and costs to change levels of machine andlabor capacity are low.2. Time flexibility strategy—using utilization as the lever: This strategy may beused if there is excess machine capacity (i.e., if machines are not used twentyfour hours a day, seven days a week). In this case, the workforce (capacity) iskept stable but the number of hours worked is varied over time in an effort tosynchronize production with demand. A planner can use variable amounts ofovertime or a flexible schedule to achieve this synchronization. Although thisstrategy does require that the workforce be flexible, it avoids some of theproblems associated with the Chase strategy, most notably changing the size of the workforce. This strategy results in low levels of inventory but with loweraverage utilization. It should be used when inventory carrying costs are relatively high and machine capacity is relatively inexpensive.3. Level strategy—using inventory as the lever: With this strategy, a stablemachine capacity and workforce are maintained with a constant output rate.Shortages and surpluses result in inventory levels fluctuating over time. Hereproduction is not synchronized with demand. Either inventories are built up inanticipation of future demand or backlogs are carried over from high- to low-demand periods. Employees benefit from stable working conditions. A drawback associated with this strategy is that large inventories may accumulate andcustomer orders may be delayed. This strategy keeps capacity and costs ofchanging capacity relatively low. It should be used when inventory carrying andbacklog costs are relatively low.Difficulty: Moderate4. Discuss key issues to be considered when implementing aggregate planning.Answer: 1. Think beyond the enterprise to the entire supply chain. Mostaggregate planning done today takes only the enterprise as its breadth of scope.However, there are many factors outside the enterprise throughout the supplychain that can dramatically impact the optimal aggregate plan. Therefore, avoidthe trap of only thinking about your enterprise when aggregate planning. Workwith partners downstream to produce forecasts, with upstream partners todetermine constraints, and with any other supply chain entities that can improve the quality of the inputs into the aggregate plan. As the plan is only as good asthe quality of the inputs, using the supply chain to increase the quality of theinputs will greatly improve the quality of the aggregate plan. Also make sure tocommunicate the aggregate plan to all supply chain partners who will be affected by it.2. Make plans flexible because forecasts are always wrong. Aggregate plans arebased on forecasts of future demand. Given that these forecasts are alwayswrong to some degree, the aggregate plan needs to have some flexibility builtinto it if it is to be useful. By building flexibility into the plan, when future demand changes, or other changes occur, such as increases in costs, the plan canappropriately adjust to handle the new situation. A manager should performsensitivity analysis on the inputs into an aggregate plan. Using sensitivityanalysis on the inputs into the aggregate plan will enable the planner to choosethe best solution for the range of possibilities that could occur.3. Rerun the aggregate plan as new data emerges. Aggregate plans provide amap for the next three to eighteen months. This does not mean that a firm should only run aggregate plans once every three to eighteen months. As inputs into the aggregate plan change, managers should use the latest values of these inputsand rerun the aggregate plan. By using the latest inputs, the plan will avoidsuboptimization based on old data and will produce a better solution. Forinstance, as new demand forecasts become available, aggregate plans shouldbe reevaluated.4. Use aggregate planning as capacity utilization increases. Surprisingly, manycompanies do not create aggregate plans and instead rely solely on orders from their distributors or warehouses to determine their production schedules. Theseorders are driven either by actual demand or through inventory managementalgorithms. If a company has no trouble efficiently meeting demand this way,then one could claim the lack of aggregate planning may not significantly harmthe company. However, when utilization becomes high and capacity is an issue, relying on orders to set the production schedule can lead to capacity problems.When utilization is high, the likelihood of producing for all the orders as theyarrive is very low. Planning needs to be done to best utilize the capacity to meet the forecasted demand. Therefore, as capacity utilization increases, it becomesmore important to perform aggregate planning.Difficulty: Moderate。

Chapter 8Aggregate Planning in the Supply ChainTrue/False1. The goal of aggregate planning is to satisfy demand in a way that minimizesprofit.Answer: FalseDifficulty: Easy2. Aggregate planning is a process by which a company determines levels ofcapacity, production, subcontracting, inventory, stockouts, and even pricing overa specified time horizon.Answer: TrueDifficulty: Moderate3. Aggregate planning solves problems involving aggregate decisions rather thanstock keeping unit (SKU) level decisions.Answer: TrueDifficulty: Easy4. Traditionally, much of aggregate planning is focused within an enterprise andmay not always be seen as a part of supply chain management.Answer: TrueDifficulty: Moderate5. Aggregate planning is an important supply chain issue because, to be effective, itrequires inputs from throughout the supply chain, but its results have little impact on the supply chain.Answer: FalseDifficulty: Moderate6. Short-term production serves as a broad blueprint for operations and establishesthe parameters within which aggregate planning decisions are made.Answer: FalseDifficulty: Easy7. The aggregate planning problem is concerned with determining the productionlevel, inventory level, and capacity level (internal and outsourced) for each period that maximizes the firm’s profit over the planning horizon.Answer: TrueDifficulty: Moderate8. To create an aggregate plan, a company must specify the planning horizon forthe plan and the duration of each period within the planning horizon.Answer: TrueDifficulty: Easy9. A planning horizon is usually between three and five years.Answer: FalseDifficulty: Moderate10. A poor aggregate plan can result in improved sales and profits if the availableinventory and capacity are unable to meet demand.Answer: FalseDifficulty: Easy11. A poor aggregate plan may result in a large amount of excess inventory andcapacity, thereby raising costs.Answer: TrueDifficulty: Moderate12. The aggregate planner must make a trade-off between capacity, inventory, andbacklog costs.Answer: TrueDifficulty: Moderate13. An aggregate plan that increases one cost typically results in the increase of theother two.Answer: FalseDifficulty: Moderate14. The time flexible strategy is where the production rate is synchronized with thedemand rate by varying machine capacity or hiring and laying off employees asthe demand rate varies.Answer: FalseDifficulty: Hard15. The time flexible strategy is where workforce (capacity) is kept stable but thenumber of hours worked is varied over time in an effort to synchronize production with demand.Answer: TrueDifficulty: Moderate16. The mixed strategy is where a stable machine capacity and workforce aremaintained with a constant output rate with inventory levels fluctuating over time.Answer: FalseDifficulty: Hard17. Most strategies that an aggregate planner actually uses are in combination, andare referred to as mixed strategies.Answer: TrueDifficulty: Easy18. A highly effective tool for a company to use when it tries to maximize profits whilebeing subjected to a series of constraints is aggregate programming.Answer: FalseDifficulty: Moderate19. To improve the quality of these aggregate plans, forecast errors must be takeninto account when formulating aggregate plans.Answer: TrueDifficulty: Moderate20. Forecasting errors are dealt with in aggregate plans using either safety backlogor safety capacity.Answer: FalseDifficulty: Moderate21. Safety inventory is defined as inventory held to satisfy demand that is higher thanforecasted.Answer: TrueDifficulty: Easy22. Safety capacity is defined as capacity used to satisfy demand that is lower thanforecasted.Answer: FalseDifficulty: Easy23. Companies should work with downstream partners to produce forecasts and withupstream partners to determine constraints when doing aggregate planning.Answer: TrueDifficulty: Easy24. The aggregate plan should be viewed primarily as an in-house tool that does notneed to be communicated to supply chain partners.Answer: FalseDifficulty: Easy25. Given that forecasts are always wrong to some degree, the aggregate planneeds to have some flexibility built into it if it is to be useful.Answer: TrueDifficulty: Moderate26. A manager should perform sensitivity analysis on the inputs into an aggregateplan to choose the best solution for the range of possibilities that could occur.Answer: TrueDifficulty: Moderate27. As inputs into the aggregate plan change, managers do not need to makechanges to the aggregate plan.Answer: FalseDifficulty: Easy28. As capacity utilization increases, it becomes less important to perform aggregateplanning.Answer: FalseDifficulty: ModerateMultiple Choice1. The process by which a company determines levels of capacity, production,subcontracting, inventory, stockouts, and even pricing over a specified timehorizon isa. aggregate planning.b. detail planning.c. inventory planning.d. sales planning.e. all of the aboveAnswer: aDifficulty: Moderate2. The goal of aggregate planning is toa. dissatisfy customers in a way that maximizes profit.b. dissatisfy customers in a way that minimizes profit.c. satisfy demand in a way that maximizes profit.d. satisfy demand in a way that minimizes profit.e. none of the aboveAnswer: cDifficulty: Easy3. Aggregate planning solves problems involvinga. aggregate decisions and stock keeping unit (SKU) level decisions.b. aggregate decisions or stock keeping unit (SKU) level decisions.c. aggregate decisions rather than stock keeping unit (SKU) level decisions.d. stock keeping unit (SKU) level decisions rather than aggregate decisions.e. b and c onlyAnswer: cDifficulty: Easy4. Aggregate planning, to be effective, requires inputs froma. all customers.b. all departments.c. all suppliers.d. throughout the supply chain.e. throughout the company.Answer: dDifficulty: Moderate5. Much of aggregate planning has traditionally been focuseda. on short-term production scheduling.b. on customer relationship management.c. within an enterprise.d. beyond enterprise boundaries.e. all of the aboveAnswer: cDifficulty: Moderate6. Which of the following are not operational parameters the aggregate planner isconcerned with?a. production rateb. workforcec. overtimed. backorderse. inventory on handAnswer: dDifficulty: Moderate7. The operational parameter concerned with the number of units completed perunit time (such as per week or per month) isa. production rate.b. workforce.c. overtime.d. backlog.e. inventory on hand.Answer: aDifficulty: Easy8. The operational parameter concerned with the number of workers/units ofcapacity needed for production isa. production rate.b. workforce.c. overtime.d. backlog.e. inventory on hand.Answer: bDifficulty: Easy9. The operational parameter concerned with the amount of overtime productionplanned isa. production rate.b. workforce.c. overtime.d. backlog.e. inventory on hand.Answer: cDifficulty: Easy10. The operational parameter concerned with demand not satisfied in the period inwhich it arises, but carried over to future periods isa. production rate.b. workforce.c. overtime.d. backlog.e. inventory on hand.Answer: dDifficulty: Easy11. The operational parameter concerned with the planned inventory carried over thevarious periods in the planning horizon isa. production rate.b. workforce.c. overtime.d. backlog.e. inventory on hand.Answer: eDifficulty: Easy12. The operational parameter concerned with the number of units of machinecapacity needed for production isa. machine capacity level.b. subcontracting.c. overtime.d. backlog.e. inventory on hand.Answer: aDifficulty: Easy13. The operational parameter concerned with the subcontracted capacity requiredover the planning horizon isa. machine capacity level.b. subcontracting.c. overtime.d. backlog.e. inventory on hand.Answer: cDifficulty: Easy14. The aggregate plana. serves as a broad blueprint for operations.b. establishes the parameters within which short-term production anddistribution decisions are made.c. allows the supply chain to alter capacity allocations and change supplycontracts.d. all of the abovee. b and c onlyAnswer: dDifficulty: Moderate15. Aggregate planning is concerned with determininga. the production level, sales level, and capacity for each period.b. the demand level, inventory level, and capacity for each period.c. the production level, inventory level, and capacity for each period.d. the production level, staffing level, and capacity for each period.e. none of the aboveAnswer: cDifficulty: Moderate16. To create an aggregate plan, a company must specifya. the planning horizon for the plan.b. the duration of each period within the planning horizon.c. key information required.d. all of the abovee. a and b onlyAnswer: dDifficulty: Moderate17. The planning horizon isa. the time period over which the aggregate plan is to produce a solution.b. the duration of each time period in the aggregate plan.c. the length of time required to produce the aggregate plan.d. the solution to the aggregate plan.e. none of the aboveAnswer: aDifficulty: Easy18. The length of the planning horizon is usually betweena. one and three months.b. three and eighteen months.c. one and three years.d. three and five years.e. none of the aboveAnswer: bDifficulty: Moderate19. Which of the following is not information needed by the aggregate planner?a. demand forecast for each period in the planning horizonb. production costsc. labor costsd. cost of subcontracting productione. cost of changing the demand forecastAnswer: eDifficulty: Moderate20. The cost of changing capacity includes thea. cost of adding machine capacity.b. cost of reducing machine capacity.c. cost of hiring workforce.d. cost of laying off workforce.e. all of the aboveAnswer: eDifficulty: Easy21. Which of the following is not a cost of changing capacity?a. cost of adding machine capacityb. cost of hiring workforcec. cost of laying off workforced. cost of overtimee. cost of reducing machine capacityAnswer: dDifficulty: Moderate22. Which of the following is not a constraint the aggregate planner needs toconsider?a. limits on stockouts and backlogsb. limits on overtimec. limits on sales commissionsd. limits on layoffse. limits on capital availableAnswer: cDifficulty: Moderate23. A poor aggregate plan can result ina. appropriate inventory levels.b. efficient use of capacity.c. better sales and lost profits.d. lost sales and lost profits.e. lost sales and better profits.Answer: dDifficulty: Hard24. The fundamental trade-offs available to an aggregate planner are betweena. capability, inventory, and backlog costs.b. capability, inventory, and sales costs.c. capacity, inventory, and backlog costs.d. capacity, inventory, and sales costs.e. none of the aboveAnswer: cDifficulty: Easy25. Which of the following is not a distinct aggregate planning strategy for achievingbalance between capacity, inventory, and backlog costs?a. adjustable strategyb. Chase strategyc. level strategyd. mixed strategye. time flexible strategyAnswer: aDifficulty: Easy26. The strategy where the production rate is synchronized with the demand rate byvarying machine capacity or hiring and laying off employees as the demand rate varies is thea. adjustable strategy.b. Chase strategy.c. level strategy.d. mixed strategy.e. time flexible strategy.Answer: bDifficulty: Moderate27. The strategy where workforce (capacity) is kept stable but the number of hoursworked is varied over time in an effort to synchronize production with demand is thea. adjustable strategy.b. Chase strategy.c. level strategy.d. mixed strategy.e. time flexible strategy.Answer: eDifficulty: Moderate28. The strategy where a stable machine capacity and workforce are maintained witha constant output rate, with inventory levels fluctuating over time, is thea. adjustable strategy.b. Chase strategy.c. level strategy.d. mixed strategy.e. time flexible strategy.Answer: cDifficulty: Hard29. Most strategies that an aggregate planner actually uses are in combination andare referred to as thea. adjustable strategy.b. Chase strategy.c. level strategy.d. mixed strategy.e. time flexible strategy.Answer: dDifficulty: Easy30. A highly effective tool for a company to use when it tries to maximize profits whilebeing subjected to a series of constraints isa. aggregate programming.b. distribution programming.c. production programming.d. linear programming.e. manufacturing programming.Answer: dDifficulty: Moderate31. When formulating aggregate plans,a. forecast errors have no impact.b. forecast errors must be taken into account.c. forecast accuracy is assumed.d. forecast accuracy is not a factor.e. none of the aboveAnswer: bDifficulty: Moderate32. Forecasting errors are dealt with usinga. safety backlog.b. safety capacity.c. safety inventory.d. all of the abovee. b and c onlyAnswer: eDifficulty: Moderate33. Inventory held to satisfy demand that is higher than forecasted isa. safety backlog.b. safety capacity.c. safety inventory.d. safety sales.e. safety workforce.Answer: cDifficulty: Easy34. Capacity used to satisfy demand that is higher than forecasted isa. safety backlog.b. safety capacity.c. safety inventory.d. safety sales.e. safety workforce.Answer: bDifficulty: Easy35. Which of the following is an approach a company can use to create a buffer forforecast error using safety inventory?a. overtimeb. carry extra workforce permanentlyc. build and carry extra inventoriesd. subcontractinge. purchase capacity or product from an open or spot marketAnswer: aDifficulty: Easy36. Which of the following is not an approach a company can use to create a bufferfor forecast error using safety capacity?a. overtimeb. carry extra workforce permanentlyc. build and carry extra inventoriesd. subcontractinge. purchase capacity or product from an open or spot marketAnswer: cDifficulty: Easy37. Aggregate planning should consider information froma. only the enterprise as its breadth of scope.b. downstream partners to produce forecasts.c. upstream partners to determine constraints.d. all of the abovee. b and c onlyAnswer: dDifficulty: Easy38. The quality of the aggregate plan can be improved by using information froma. only the local firm.b. only downstream partners.c. only upstream partners.d. all parts of the supply chain.e. none of the aboveAnswer: bDifficulty: Moderate39. The aggregate plan should be communicated toa. only the local firm.b. only downstream partners.c. only upstream partners.d. all supply chain partners who will be affected by it.e. none of the aboveAnswer: cDifficulty: Moderate40. The aggregate plan needs toa. be a final product because changes are disruptive to the supply chain.b. be considered fixed because forecasts are usually accurate.c. have some flexibility built into it because forecasts are always wrong.d. have some flexibility built into it because forecasts are usually right.e. none of the aboveAnswer: cDifficulty: Moderate41. How frequently should the aggregate plan be rerun?a. weeklyb. monthlyc. every 3 to 8 monthsd. as inputs to the aggregate plan changee. neverAnswer: dDifficulty: Hard42. As capacity utilization increases,a. it becomes less important to perform aggregate planning.b. it becomes more important to perform aggregate planning.c. it does not affect the importance of performing aggregate planning.d. it lessens the importance of aggregate planning.e. none of the aboveAnswer: bDifficulty: ModerateEssay/Problems1. Discuss the primary objective and operational parameters of aggregate planning.Answer: The goal of aggregate planning is to satisfy demand in a way thatmaximizes profit. Aggregate planning is a process by which a companydetermines levels of capacity, production, subcontracting, inventory, stockouts,and even pricing over a specified time horizon. The aggregate planner’s mainobjective is to identify the following operational parameters over the specifiedtime horizon:• Production rate: the number of units completed per unit time (such as per week or per month).• Workforce: the number of workers/units of capacity needed for production.• Overtime: the amount of overtime production planned.• Machine capacity level: the number of units of machine capacity needed forproduction.• Subcontracting: the subcontracted capacity required over the planning horizon.• Backlog: demand not satisfied in the period in which it arises but carried over to future periods.• Inventory on hand: the planned inventory carried over the various periods in the planning horizon.The aggregate plan serves as a broad blueprint for operations and establishesthe parameters within which short-term production and distribution decisions are made. The aggregate plan allows the supply chain to alter capacity allocationsand change supply contracts.Difficulty: Moderate2. Discuss the information required for aggregate planning.Answer: An aggregate planner requires the following information:• Demand forecast F t for each Period t in the planning horizon that extends over T periods• Production cos ts• Labor costs, regular time ($/hour), and overtime costs ($/hour)• Cost of subcontracting production ($/unit or $/hour)• Cost of changing capacity; specifically, cost of hiring/laying off workforce($/worker) and cost of adding or reducing machine capacity ($/machine)• Labor/machine hours required per unit• Inventory holding cost ($/unit/period)• Stockout or backlog cost ($/unit/period)• Constraints:• Limits on overtime• Limits on layoffs• Limits on capital available• Limits on stockouts and ba cklogs• Constraints from suppliers to the enterpriseThis information is used to create an aggregate plan that in turn helps a company make the following determinations:• Production quantity from regular time, overtime, and subcontracted time:used to determine number of workers and supplier purchase levels.• Inventory held: used to determine how much warehouse space andworking capital is needed.• Backlog/stockout quantity: used to determine what the customer servicelevels will be.• Workforce hired/laid off: used to determine any labor issues that will beencountered.• Machine capacity increase/decrease: used to determine if newproduction equipment needs to be purchased or idled.The quality of an aggregate plan has a significant impact on the profitability of a firm. A poor aggregate plan can result in lost sales and lost profits if the available inventory and capacity are unable to meet demand. A poor aggregate plan mayalso result in a large amount of excess inventory and capacity, thereby raisingcosts. Therefore, aggregate planning is a very important tool in helping a supply chain maximize profitability.Difficulty: Hard3. Explain the basic strategies that an aggregate planner has available to balancethe various costs and meet demand.Answer: There are essentially three distinct aggregate planning strategies forachieving balance between these costs. These strategies involve trade-offsbetween capital investment, workforce size, work hours, inventory, andbacklogs/lost sales. Most strategies that a planner actually uses are acombination of these three and are referred to as mixed strategies. The threestrategies are as follows:1. Chase strategy—using capacity as the lever: With this strategy, the productionrate is synchronized with the demand rate by varying machine capacity or hiring and laying off employees as the demand rate varies. In practice, achieving thissynchronization can be very problematic because of the difficulty in varyingcapacity and workforce on short notice. This strategy can be expensive toimplement if the cost of varying machine or labor capacity over time is high. Itcan also have a significant negative impact on the morale of the workforce. TheChase strategy results in low levels of inventory in the supply chain and highlevels of change in capacity and workforce. It should be used when the cost ofcarrying inventory is very expensive and costs to change levels of machine andlabor capacity are low.2. Time flexibility strategy—using utilization as the lever: This strategy may beused if there is excess machine capacity (i.e., if machines are not used twentyfour hours a day, seven days a week). In this case, the workforce (capacity) iskept stable but the number of hours worked is varied over time in an effort tosynchronize production with demand. A planner can use variable amounts ofovertime or a flexible schedule to achieve this synchronization. Although thisstrategy does require that the workforce be flexible, it avoids some of theproblems associated with the Chase strategy, most notably changing the size of the workforce. This strategy results in low levels of inventory but with loweraverage utilization. It should be used when inventory carrying costs are relatively high and machine capacity is relatively inexpensive.3. Level strategy—using inventory as the lever: With this strategy, a stablemachine capacity and workforce are maintained with a constant output rate.Shortages and surpluses result in inventory levels fluctuating over time. Hereproduction is not synchronized with demand. Either inventories are built up inanticipation of future demand or backlogs are carried over from high- to low-demand periods. Employees benefit from stable working conditions. A drawback associated with this strategy is that large inventories may accumulate andcustomer orders may be delayed. This strategy keeps capacity and costs ofchanging capacity relatively low. It should be used when inventory carrying andbacklog costs are relatively low.Difficulty: Moderate4. Discuss key issues to be considered when implementing aggregate planning.Answer: 1. Think beyond the enterprise to the entire supply chain. Mostaggregate planning done today takes only the enterprise as its breadth of scope.However, there are many factors outside the enterprise throughout the supplychain that can dramatically impact the optimal aggregate plan. Therefore, avoidthe trap of only thinking about your enterprise when aggregate planning. Workwith partners downstream to produce forecasts, with upstream partners todetermine constraints, and with any other supply chain entities that can improve the quality of the inputs into the aggregate plan. As the plan is only as good asthe quality of the inputs, using the supply chain to increase the quality of theinputs will greatly improve the quality of the aggregate plan. Also make sure tocommunicate the aggregate plan to all supply chain partners who will be affected by it.2. Make plans flexible because forecasts are always wrong. Aggregate plans arebased on forecasts of future demand. Given that these forecasts are alwayswrong to some degree, the aggregate plan needs to have some flexibility builtinto it if it is to be useful. By building flexibility into the plan, when future demand changes, or other changes occur, such as increases in costs, the plan canappropriately adjust to handle the new situation. A manager should performsensitivity analysis on the inputs into an aggregate plan. Using sensitivityanalysis on the inputs into the aggregate plan will enable the planner to choosethe best solution for the range of possibilities that could occur.3. Rerun the aggregate plan as new data emerges. Aggregate plans provide amap for the next three to eighteen months. This does not mean that a firm should only run aggregate plans once every three to eighteen months. As inputs into the aggregate plan change, managers should use the latest values of these inputsand rerun the aggregate plan. By using the latest inputs, the plan will avoidsuboptimization based on old data and will produce a better solution. Forinstance, as new demand forecasts become available, aggregate plans shouldbe reevaluated.4. Use aggregate planning as capacity utilization increases. Surprisingly, manycompanies do not create aggregate plans and instead rely solely on orders from their distributors or warehouses to determine their production schedules. Theseorders are driven either by actual demand or through inventory managementalgorithms. If a company has no trouble efficiently meeting demand this way,then one could claim the lack of aggregate planning may not significantly harmthe company. However, when utilization becomes high and capacity is an issue, relying on orders to set the production schedule can lead to capacity problems.When utilization is high, the likelihood of producing for all the orders as theyarrive is very low. Planning needs to be done to best utilize the capacity to meet the forecasted demand. Therefore, as capacity utilization increases, it becomesmore important to perform aggregate planning.Difficulty: Moderate。

An agent-based simulation system for concert venue crowd evacuation modeling in the presence of a firedisasterNeal Wagner,Vikas Agrawal ⇑Fayetteville State University,School of Business and Economics,1200Murchison Road,Fayetteville,NC,USAa r t i c l e i n f o Keywords:Modeling and simulation Agent-based system Crowd evacuation Disaster mitigationEmergency preparednessa b s t r a c tA key activity in emergency management is planning and preparation for disaster.If the right safety mea-sures are implemented beforehand,harmful effects can be significantly mitigated.However,evaluation and selection of effective measures is difficult due to the numerous scenarios that exist in most emer-gency environments coupled with the high associated cost of testing such scenarios.An agent-based sys-tem employs a computational model of autonomous interacting agents in an environment with the purpose of assessing the emergent behavior of the group.This paper presents a prototype of a computer simulation and decision support system that uses agent-based modeling to simulate crowd evacuation in the presence of a fire disaster and provides for testing of multiple disaster scenarios at virtually no cost.The prototype is unique in the current literature as it is specifically designed to simulate a concert venue setting such as a stadium or auditorium and is highly configurable allowing for user definition of concert venues with any arrangement of seats,pathways,stages,exits,and people as well as the definition of multiple fires with fire and smoke dynamics included.Ó2013Elsevier Ltd.All rights reserved.1.IntroductionOf paramount importance to emergency managers is the ques-tion of how to prepare for as yet unseen disasters.Proper safety measures can literally mean the difference between life and death for large groups of affected people.However,emergency situations and their associated safety measures are highly specific to the envi-ronment in which they exist and there are generally numerous sce-narios that must be considered.The cost of testing these multiple scenarios is oftentimes prohibitive (Jain &McLean,2008).Thus,evaluation and selection of effective safety measures for emer-gency preparedness is quite difficult and is often left to the subjec-tive judgment of an emergency manager.Computer modeling and simulation seeks to remedy this prob-lem by allowing for testing of multiple environment-specific scenarios at low cost.Agent-based systems use a computational model of autonomous agents that move and interact with each other and their environment.Such systems use a bottom-up modeling approach in which system control is decentralized and governed only by the behavior of the agents (Borshchev &Filippov,2004).Agent-based modeling is the preferable technique for simu-lation of systems with a large number of active objects (e.g.,peo-ple,business units,animals,etc.)that are dependent on the order/timing of events for the following reasons:(1)it allows for the capture of highly complex dynamics,(2)it can be implemented with little or no knowledge of the global interdependencies and/or aggregate effects of the system,and (3)it is easier to build upon as model changes generally require local not global adjustments (Bor-shchev &Filippov,2004).The development of agent-based systems for emergency planning and preparedness remains an open re-search area as there exist a multitude of disaster environments that have yet to be addressed (Jain &McLean,2008).This paper presents a prototype of an Agent-based Decision Support System (ABS)for the simulation of crowd evacuation in the presence of a fire disaster for venues that are specifically in-tended for mass gatherings such as stadiums and auditoriums.The goal of the system is to allow for multiple scenario testing and decision support for the planning and preparedness phase of emergency management with regards to fire disasters at concert venues.The system is designed for emergency managers,police,and any administrators who are charged with fire disaster mitiga-tion planning for concert ers of the system can benefit by evaluating the effects of potential safety measures such as restrictions on the maximum number of people,wider pathways,additional exits,and fewer seats on crowd evacuation dynamics.The system is unique as it is specifically designed to simulate evac-uation of a concert venue setting rather than an urban roadways or building evacuation setting as is prevalent in the literature.High0957-4174/$-see front matter Ó2013Elsevier Ltd.All rights reserved./10.1016/j.eswa.2013.10.013⇑Corresponding author.Tel.:+19106721338.E-mail addresses:nwagner@ (N.Wagner),vagrawal@ (V.Agrawal).URLs: (N.Wagner),/vagrawal/(V.Agrawal).densities of people and relatively limited exit routes and exit points are common characteristics of concert venues and their combination make such venues a significant concern for emer-gency managers.Additionally,the ABS system is highly configura-ble allowing for user definition of a concert venue with any number and arrangement of seats and bleachers,aisles and path ways,stages and playingfields,exits,and people and also allows for the definition of multiplefires with dynamics offire spreading and smoke production included.The contribution of this study is twofold:1.It provides an agent-based system that is specifically designedfor crowd evacuation simulation of concert venues during afire disaster.2.The system is built for customization and provides to the userthe ability to define the layout and structure of the concert venue to be simulated.This allows the user to replicate the venue of concern and provides decision support for the plan-ning and preparedness phases of emergency management.The rest of this paper is organized as follows:Section2provides a brief survey of the current research on agent-based systems for crowd evacuation modeling,Section3gives a description of the prototype ABS system,Section4details experiments conducted using the system to simulate disaster scenarios for simulated rep-licas of actual concert venues,and Section5discusses future work necessary to enhance and transition this prototype system into a viable commercial software system.2.Review of current researchRecent advances in computational speed have made the con-struction of complex simulation systems more feasible.Several re-cent studies involving agent-based models for crowd evacuation simulation exist in the current literature.These studies generally fall into one of three categories:(1)crowd evacuation of buildings, (2)crowd evacuation for urban roadways,and(3)crowd behavior during evacuation.Bonomi,Manzoni,Pisano,and Vizzari(2009),Braun,Bodmann, and Musse(2005),Camillen et al.(2009),Fangqin and Aizhu (2008),Filippoupolitis,Hey,Loukas,Gelenbe,and Timotheou (2008),Ha and Lykotrafitis(2012),He and Zhao(2010),Massaguer, Balasubramanian,Mehrotra,and Venkatasubramanian(2006), Okaya and Takahashi(2011),Pan,Han,Dauber,and Law(2006), Pelechano and Badler(2006),Shi,Ren,and Chen(2009),Tang and Ren(2008),Yamamoto(2013),Yang,Wang,and Liu(2011, 2012)apply agent-based modeling to simulate the evacuation of buildings.In Ha and Lykotrafitis(2012)an agent-based system is used to model panic effects during evacuation of a building. Filippoupolitis et al.(2008),Shi et al.(2009),Tang and Ren (2008),Yang et al.(2011)provide an agent-based model to simu-late building evacuation during afire disaster.Fangqin and Aizhu (2008)provides an agent-based simulation model for building evacuation during afire disaster which uses computationalfluid dynamics to modelfire dynamics and spatial analysis of GIS data to model peoples’knowledge of the building structure.Okaya and Takahashi(2011)employs a Belief-Desire-Intention(BDI) model to model human relationships and investigate their effects on building evacuation dynamics.Pelechano and Badler(2006) developed a simulation model for building evacuation by crowds who might not know the structure’s connectivity or whofind routes accidentally blocked.Yamamoto(2013)provides an agent-based model to simulate building evacuations during earth-quake andfire disasters.Yang et al.(2012)integrates multiple agent-based models at differing resolutions(i.e.,macro resolution and micro resolution)to simulate building evacuation dynamics.Anh,Daniel,Du,Drogoul,and An(2012),Handford and Rogers (2011),Lucas,Martinez,Sickinger,and Roginski(2007), Shendarkar,Vasudevan,Lee,and Son(2006),Balmer,Nagel,and Raney(2004)employ agent-based modeling to simulate crowd evacuation dynamics of urban roadways.Anh et al.(2012)provides a hybrid agent-based model for roadway evacuation simulation that combines macro and micro level simulations to increase overall simulation efficiency while capturing necessary low-level simulation details.In Lucas et al.(2007)and Shendarkar et al. (2006)emergency aspects of an urban roadway evacuation are modeled includingfires,gunmen,and police personnel.In Handford and Rogers(2011)the interdependency of driver behav-iors is modeled in the context of roadway evacuation.Banerjee,Abukmail,and Kraemer(2009),Ben,Huang,Zhuang, Yan,and Xu(2013),Chu,Pan,and Law(2011),Heliövaara, Korhonen,Hostikka,and Ehtamo(2012),Laughery(2001),Lee, Son,and Jin(2010),Liang,Low,Lees,Cai,and Zhou(2010),Norling (2004),Pan,Han,Dauber,and Law(2007),Ren,Yang,and Jin (2009),Sharma and Lohgaonkar(2010),Tsai et al.(2011),Wang, Li,Liu,and Cui(2011),Yang,Ren,and Wu(2012)apply agent-based models to study crowd behavior during evacuation.Banerjee et al.(2009)employs a layered intelligence model to efficiently simulate agent-based crowd evacuation and demonstrate the mod-el’s scalability to larger numbers of agents.In Ben et al.(2013)the evacuation environment is modeled using a cellular automata model while an agent-based model governs the behavior of evacu-ees.The model is used to study evacuation dynamics in environ-ments with and without obstacles.Chu et al.(2011)incorporates behavioral theories from social science concerning group affilia-tions,group influences,and intra-group roles to model crowd evac-uation dynamics.Heliövaara et al.(2012)uses an agent-based model to study crowd behavior in counterflow situations,that is situations in which groups of agents have opposing directions of ughery(2001),Lee et al.(2010),Norling(2004)em-ploy a BDI framework to model the decision-making process of individuals in crowd evacuation scenarios.Liang et al.(2010) investigates the use of embedding information into the evacuation environment in order to influence crowd behavior in an evacua-tion.Pan et al.(2007)uses a multi-agent model to simulate behav-ior during evacuation that exhibits competitive,queuing,and herding behaviors while Ren et al.(2009)uses an agent-based model to simulate evacuation during an explosion disaster.Sharma and Lohgaonkar(2010)provides an agent-based model that has a fuzzy logic component for simulating human behavior and deci-sioning in an evacuation.The model is used to capture both indi-vidual and group behaviors in an emergency evacuation scenario. Tsai et al.(2011)provides a multi-agent evacuation simulation tool called ESCAPES that is specific to the airport domain and incorpo-rates varying agent types,emotional interactions,informational interactions,and behavioral interactions.Wang et al.(2011)em-ploys an ant colony evacuation model that includes avoidance and preferential path selection behaviors.Yang et al.(2012)pro-poses a multi-resolution agent-based model to simulate pedestrian flow in an evacuation.A few studies have focused on specialized applications of agent-based crowd evacuation models.Carroll,Owen,and Hussein(2012) applies an agent-based model to simulate evacuation from a foot bridge.Song et al.(2013)employs an agent-based model to simu-late evacuation from a train station under a bioterrorism attack. Wei,Xiong,Zhang,and Chen(2011)uses a grid simulation frame-work to address simulation efficiency for large agent-based evacu-ation models.Chen,Wang,and Liu(2011)provides a study that incorporates GIS data into a multi-agent system to simulate non-emergency evacuation of a sports stadium.Of all the recent studies described above,the model of Chen et al.(2011)is the one that is most comparable to the model2808N.Wagner,V.Agrawal/Expert Systems with Applications41(2014)2807–2815presented in this paper as it is focused on crowd evacuation of a concert venue(in this case a sports stadium).However,there are two main differences between the two models:(1)the model of this paper is designed to simulate any concert venue and allows for user definition of the layout and structure of the concert venue to be modeled while the model of Chen et al.(2011)is specific to a particular concert venue and does not allow for user customization and(2)the proposed model is designed to simulate emergency evacuation in the presence of afire disaster and includesfire and smoke dynamics while the model of Chen et al.(2011)simulates a non-emergency evacuation.As detailed in the previous section,the ABS system presented in this paper provides a unique contribution as it is specifically built for crowd evacuation of concert venues under afire disaster and it allows for extensive user customization of the concert venue to be simulated.The prototype system is intended to be a decision sup-port tool for the planning and preparedness phases of emergency management and seeks to mitigate the impact offire disasters by allowing managers to simulate multiple scenarios and evaluate the effectiveness of potential safety measures to be implemented before a disaster occurrence.The following section describes the ABS system.3.ABS simulation systemThe prototype ABS system is designed to model a concert venue that includes seats,aisle and path ways,stages/playingfields,exits, and people.It allows for the specification of multiplefire with dynamics offire spreading and smoke production included.The goal of the system is to simulate crowd evacuation for concert ve-nue settings such as found in stadiums,auditoriums,or concert halls.The system uses an agent-based modeling approach in which individual autonomous agents interact with each other and their environment.In this application agents are people who are located in seats,path ways,and stages and are trying to quickly move to an exit while avoiding one or morefires.Fires are also represented as agents which are created and which spread and produce smoke. The system is intended for use in the planning and preparedness phases of emergency management and offers the following bene-fits to emergency managers and other administrators charged with fire disaster mitigation planning for a concert venue.1.The ability to specify customized environments with any num-ber and arrangement of seats,path ways,stages/playingfields, exits,and people.This allows managers to more accurately rep-licate the stadia/auditoriums that are of interest to them.2.The ability to specify multiplefires each with user-specifiedfirespread and smoke production rates.3.The ability to simulate multiple scenarios and safety measures(e.g.,wider path ways,additional exits,etc.)at virtually no costand with relatively fast result turnaround.This allows managers to test a large number of possibilities and makes for better eval-uation of the various safety measures.Ultimately,this leads to planning decisions that are data-driven rather than subjective.The ABS system is implemented using a combination of NetLogo (an agent-based modeling and simulation development environ-ment)and Java programming languages.The following sections de-scribe the three major components of the system:environment setup,fire dynamics,and person movement.3.1.Environment setupFor managers and planners,the ability to construct simulation environments that are relevant to their concerns is critical.The use of generic simulations may be helpful for general training pur-poses but in the end planners wish to accurately replicate the envi-ronment that they are obligated to protect.The ABS system is designed to be highly customizable and allows for the specification of any setup of seats or bleachers,aisle and path ways,stages or playingfields,exits,and people.In a concert venue setting there is a large concentration of peo-ple in a small enclosed area and many of them will be viewing the event from the seating area.Seats are specified in groups or blocks made up of rows and columns(i.e.,number of seats per row).The user specifies the number of rows and number of seats per row as well as the direction for the seats to face and the location(x–y coordinate)for placement of the block of seats.Additionally,the aisle width and separation between seats in a row can be specified by the user.In order to maintain the correct separation and aisle width for blocks of seats facing potentially at any angle,the system internally represents seats using the polar coordinate system and converts these to Cartesian coordinates for placement in the x–y plane.Concert venues can have varying structures and differing setups for path ways between seating areas,stages,and exits.To allow for the configuration of a wide range of possible path ways,the system represents path ways as polygons each defined by a set of vertices. The user specifies the x–y coordinates of the vertices for each polygonal path way via an inputfile.The system then‘‘draws’’these path ways on the environment.To correctly paint the inside of polygonal path ways,the ray-casting geometrical algorithm is used to determine if a point is inside a polygon or not.The algo-rithm uses a horizontal ray emanating from the point to be tested and calculates the number of intersections with line segments that make up the polygon.1An advantage of the ray-casting algorithm is its fast computation time.However,a drawback of the algorithm is that it may give inconsistent results for points that lie directly on an edge of the polygon.In order to overcome this drawback,the following heuristic is used.First,the ray-casting algorithm is used to paint all points on the interior of a polygon.Then,the edges of the polygon are col-ored by a temporary painting agent that traverses the vertices of the polygon,painting as it travels.After all polygons are drawn on the environment,this painting agent is discarded.Stages and/or playingfields can also occur in a variety of shapes and configurations,and thus the system represents these as polyg-onal structures as well.The user specifies these in the same way as for path ways,via a set of vertices.The system paints pathways and stages in(differing)colors that can also be set by the ers can specify an exit via an x–y coordinate location and an outgoing direction.Exits can be placed at the boundary of simulation envi-ronment or at any inner location if rge exit ways can be specified as a sequence of several exits side by side.The system allows for the placement of people in seating areas, in path ways,and on stages/playingfields.The number of people to be placed in each of these areas is controlled by the user.This al-lows managers to test several event scenarios including scenarios in which people are entering or leaving the venue before or after the event as well as scenarios in which most of the people are seated during the event.Fig.1gives an example simulation environment(without peo-ple)constructed by the system.In thefigure the path ways are col-ored gray,the stage is yellow,and the seats are brown.There are two exits colored yellow in the east and west directions.There are six blocks of seats:two blocks of seats are placed to the left of the simulation environment and are facing east,two blocks1For more information on the ray-casting geometric algorithm,please see Sutherland,Sproull,and Schumaker(1974).N.Wagner,V.Agrawal/Expert Systems with Applications41(2014)2807–28152809are placed to the right and facing west,one block is placed in the upper half of the environment and is facing south,and one block is placed in the lower half and is facing north.Often a concert hall or auditorium may have not only rectangu-lar blocks of seats in which the rows are straight(such as seen in Fig.1)but also blocks of seats with curved rows.The system allows for the specification of blocks of seats with curved rows via an in-putfile.For example,Fig.2shows the same environment as shown in Fig.1with an additional4‘‘curved blocks’’of seats in the north-east,southeast,southwest,and northwest corners of the environment.The system uses an algorithm based on quadratic Bézier curves to plot blocks of seats with curved rows.Quadratic Bézier curves require a start and end point for the curve and a control point which governs the curvature produced.The user specifies the start, end,and control points for the backmost row of seats to be made. The user also specifies the number of rows to be drawn and the point that the seats in the rows should face.The system then draws the backmost row of seats using the quadratic Bézier curve equa-tion given in Eq.(1).In the equation P0and P2are the start and end points of the curve,P1is the control point and t is a curve trac-ing parameter that varies between0and1(t=0defines the start point,t=1defines the end point).BðtÞ¼ð1ÀtÞ2P0þ2ð1ÀtÞtP1þt2P2;t2½0;1 ð1ÞAfter drawing the backmost row of seats,the system then calculates new start,end,and control points for the2nd backmost row which will have fewer seats and be closer to the specified facing point.A new start point is calculated by making a ray from the start point toward the facing point and calculating the x–y coordinate on the ray that is the correct aisle width distance away from the start point.The new end point and control point are made in a similar way.The system then uses these new points and Eq.(1)to draw the2nd backmost curved row of seats.This procedure is then repeated until all rows have plotted.It should be noted that the curve tracing parameter t in Eq.(1)does not directly correlate to a distance between points on the curve and that varying t in regular intervals does not guarantee that points(and,thus seats)are placed with equivalent spacing in-between each pair of seats(Farin,1997). In order to ensure seats are spaced evenly throughout a curved row, the following algorithm is used.1.The curve tracing parameter t is initialized to0and a seat isplaced at the start point of the curve.2.A new point on the curve is generated using Eq.(1)by increas-ing parameter t by a small increment and then the distance of this point to the last placed seat is calculated.3.If this distance is equivalent to the desired amount of spacing,aseat is placed at this point.If not,step2is repeated until a point that is the correct distance from the last placed seat is found.A new seat is then placed at this point.4.New seats are placed using steps2and3above until the lastseat placed has reached the end point of the row.3.2.Fire dynamicsAs mentioned above a user can specify multiplefires with asso-ciated rates offire spreading and smoke production.Fires,like peo-ple,are represented as agents in the system.Afire will spread in a random direction at the specified rate and will produce smoke at the specified production rate.In the simulation environment agents representing people can be hurt either by being burned byfire or from accumulated smoke.The user specifies the mini-mum distance that a person must be from afire before getting burned.The user also specifies the total amount of smoke that peo-ple in the simulation environment can tolerate before suffering from asphyxiation.As thefire(s)spread and produce smoke,the system records the amount of accumulated smoke and the number of people hurt by getting burned.Once the amount of smoke in the environment reaches the user-specified threshold,all remaining people in the environment(i.e.,those who have not yet exited) are recorded as hurt.Fig.1.Example simulation environment without people.Fig.2.Example simulation environment with curved rows of seats.3.3.Person movementThe purpose of the system is to simulateple in a concert venue environment underPeople in the environment have one goal:exit while avoidingfire.The algorithmment consists of three components:from the seating area to a path way,andway toward the selected exit.These threeenced by a fourth component governingfireof the simulation,fire(s)are created andor in a path way select an exit.Each personto him/herself that is not blocked byfire.Ato be blocked byfire if afire is within adistance from the exit or if thefire isand the exit.Once an exit has been selected,peoplemove from their seat down an aisle towardin a front or side row seat may movethat direction represents the shortest way toward his/her desired exit.A person not in a front or side row seat must move to an adja-cent seat in the same row in the direction that represents theshortest way toward his/her desired exit.The system determines the type of seat a person is currently located at(i.e.,front row,side row,or neither)by making a short distance scan of the area around the current seat in search of other seats directly in front or to the side.In order to determine which direction down an aisle a person should go to move toward his/her desired exit,the system calcu-lates the distance from the exit to each of the adjacent seats(left and right)and selects the seat that is closer to the exit.People move from seat to seat down an aisle in this way until they reach a front or side row seat,and then can move directly onto a path way.People on a path way must move toward their desired exit while staying on the path.As discussed in Section3.1,the system paints path ways on the simulation environment.The environment is made up of many square shaped‘‘patches’’some of which are colored to represent a path way.Each path patch stores four direc-tions representing north,south,east,and west.During environ-ment setup,the system calculates allowed directions for each path patch by making a short distance scan from the center of the patch in each of these four directions in search of other patches that are not colored as a path way.If a scan from a path patch in a particular direction yields a non-path patch,then that direction is disallowed for the path patch in question.For example,if a patch is located in the middle of a wide path way,then the scans in each direction will not yield any non-path patches as this patch is sur-rounded by path patches.Thus,this patch will have four valid directions meaning that a person on this patch may move north, south,east,or west without moving off the path.If a patch is lo-cated on the edge of a path way,then the scan in one(or more) of the four directions will yield a non-path patch.This patch will then remove that direction from its list of valid directions meaning that a person on this patch will be disallowed from moving in that direction.Thus,a person is moved along a path by selecting a valid direction from the patch that he/she is currently located at and moving some(user-specified)maximum distance.A person chooses from the available valid directions by calculating the absolute angular difference between each valid direction and the direction directly facing the desired exit.The valid patch direction with the minimum angular difference is then selected. Fig.3depicts an example direction selection of a person on a path patch.In thefigure,a person must select one direction from three valid patch directions:north,east,and south,respec-tively(for this example suppose that the west direction is not valid for this patch).h1in thefigure represents the angle be-tween the north patch heading and the heading directly facing the desired exit.h2and h3represent similar angles for the east and south patch headings,respectively.For this case,h2has the minimum value and,thus the east patch direction is selected by the person agent.Although people on a path way may only move in one of four directions,fine-grained movement can be achieved by decreasing the size of the patches(and thereby increasing the total number of patches in the environment).In the system patch size is a parameter that is specified by the user.Fine-grained movement can also be achieved by increasing the number of possible valid patch directions,for example,by adding northeast,southeast, southwest,and northwest directions.Although the current proto-type only includes four possible patch directions,the system can easily be extend to include more directions.Both of the above mentioned methods will increase the computational burden of the system as increasing the number of patches means that the system must process more objects and increasing the number of possible patch directions means the system must execute more computations per patch.Stages are represented in the same way as path ways and,thus,movement of people on stages is handled in the same way as described above.Asfires spread during a simulation run,exits that were origi-nally unblocked byfire may become blocked.At each simulation step a person in the seating area or on a path way rechecks his/ her desired exit and,if it is blocked,chooses a different exit in the same way as described above.Additionally as a person moves along a path way or down an aisle,fire may spread to block the path or aisle.At each simulation step a person makes a medium-range scan of the area in the direction he/she is heading in search offires blocking the way.If any exist,the person recalculates his/ her direction by removing the current direction from consideration and selecting a new direction in the same way as previously de-scribed.In this way a person attempts to avoidfire while moving toward an unblocked exit in a changing environment.Fig.4displays a replica created by the system of a real audito-rium at a mid-sized university.Thefigure contains people andfires and represents the state of the simulation world at a single point of time during a simulation run.In thefigure there are two sets of ex-its(colored yellow),one to the south and one to the east with four blocks of curved row seats facing a small yellow colored stage(po-dium).In thefigure pathways are colored gray and afire is present at the south exits.Fig.3.Person Movement.N.。

AggregateIntroductionAggregation, in general, refers to the process of collecting and combining different pieces of information or data to provide a comprehensive and summarized view. It plays a crucial role in various fields such as statistics, data analysis, business intelligence, and information retrieval. This article aims to explore the concept of aggregation, its importance, common techniques, and real-world applications.Why is aggregation important?Aggregation is essential for several reasons:1. Simplification and SummarizationAggregating data allows us to simplify complex information and presentit in a concise form. It helps in gaining a better understanding by summarizing large volumes of data into meaningful insights. For instance, a company dealing with sales data may aggregate the daily sales of different stores to analyze overall performance and identify trends.2. Decision MakingAggregated information facilitates informed decision-making. By aggregating relevant data, decision-makers can quickly grasp the big picture instead of getting lost in the details. For example, a government agency may aggregate crime data from various sources to identify high-crime areas and allocate resources accordingly.3. Performance Measurement and ComparisonAggregating data enables performance measurement at different levels. By consolidating data from multiple sources, organizations can assess theiroverall performance and compare it against benchmarks or targets. This provides valuable insights into areas of improvement. An educational institution, for example, may aggregate students’ test scores to evaluate the effectiveness of teaching methods.Techniques for aggregationSeveral techniques are commonly employed to perform aggregation. Here are some prominent methods:1. SummarizationSummarization is a basic form of aggregation that involves calculating summary statistics such as mean, median, mode, or standard deviation. It provides a high-level overview of the data without delving into individual data points. For instance, a weather forecasting service may aggregate daily temperature readings to provide average monthly temperatures for a particular region.2. GroupingGrouping involves categorizing data into distinct groups based on a specific criterion. It allows for aggregation within each group separately. For example, an e-commerce platform may group customers by location and then aggregate the total sales for each geographical region independently.3. FilteringFiltering is the process of selecting a subset of data based on particular criteria. It helps in aggregating data that meets specific conditions. For instance, a marketing team may aggregate customer feedback only for those who have rated a product higher than four stars.4. Roll-upRoll-up aggregation involves summarizing data at a higher level of granularity. It is often used in hierarchical data structures. Forexample, in a sales organization, individual sales representatives’ data may be rolled up to obtain regional or national sales figures.5. Drill-downDrill-down aggregation is the opposite of roll-up. It involves breaking down aggregated data into finer details. It allows for a more detailed analysis when needed. A financial institution, for instance, may drill down into aggregated profit figures to examine the performance of individual investment portfolios.Real-world applications of aggregationAggregation is widely used across various industries and domains. Here are a few practical examples:1. Business IntelligenceIn business intelligence, aggregation plays a pivotal role in analyzing large volumes of data to discover meaningful patterns and trends. It helps businesses make informed decisions and drive growth. For instance, an e-commerce company can aggregate website traffic data to identify peak hours and optimize server capacities accordingly.2. Finance and InvestmentAggregation is crucial in the financial sector to track market performance, manage portfolios, and measure risk. Investment firms often aggregate data from multiple sources like financial markets, economic indicators, and company reports to make informed investment decisions.3. Social Media AnalyticsAggregation techniques are extensively used in social media analytics to summarize and analyze vast amounts of user-generated content. This helps marketers understand trends, analyze sentiment, and manage reputation. For example, social media aggregators can collect and analyze tweets related to a brand to gauge public perception.4. Health Data AnalysisAggregating health data from electronic medical records, wearable devices, and patient surveys enables healthcare providers to gain insights into disease prevalence, treatment outcomes, and public health trends. By analyzing aggregated data, researchers can identify risk factors, develop interventions, and improve healthcare delivery.5. Statistical AnalysisAggregation is an integral part of statistical analysis. It allows researchers to summarize data, calculate averages, and draw conclusions. Surveys and opinion polls often employ aggregation techniques to compute statistics, interpret results, and present findings.ConclusionAggregation, often seen as a fundamental concept in data management and analysis, plays a crucial role in simplifying, summarizing, and making sense of complex information. It enables decision-makers to gain valuable insights, measure performance, and compare different datasets. It finds applications in a wide range of fields, from finance to healthcare, and from business intelligence to social media analytics. Understanding and mastering aggregation techniques are essential for professionals working with data and for utilizing data-driven strategies effectively.。

Chapter 4 Production planing systemsCheng Guoping1.Production -planning hierarchyFigure 9.1 (p. 331)2.Aggregate planningAggregate is medium-range capacity planning that typically covers a time horizon of anywhere from 2 to 12 months.The goal of aggregate planning is to achieve a production plan that will effectively utilize the organization's resources to satisfy expected demand.Planners must make decisions on output rates, employment levels and changes, inventory levels and changes, back orders, and subcontracting.2.1Necessity of aggregate planning2.2Demand and capacity options(1)Demand options●PricingPricing differentials are commonly used to shift demand from peak periods to off-peak periods.●PromotionAd. And other forms of promotion, such as displays and direct marketing●Backorders●New demandsPublic transportation--creating new demands for buses at other times(2)Capacity options●Hire and fire workers--Union contracts●Overtime/slack time●Part-time workers●Inventories●Subcontracting2.3Basic strategies for meeting uneven demand(1)Level capacity strategy--Maintaining a steady rate of regular-time output while meeting variations in demand by a combination of options, such as inventory, overtime, subcontracting, part-time workers, etc.(2)Chase demand strategy--Matching capacity to demand. The planned output for a period would be the expected demand for that period.Advantages and disadvantages(3)Maintain a level work force2.4Steps in aggregate planning(1)Determine demand for each period(2)Determine capacities for each period(3)Determine company or departmental policies that arepertinent(4)Determine unit costs for regular time, overtime,subcontracting, holding inventories, back orders, and other relevant costs.(5)Develop alternative plans and compute the cost for each(6)Select one plan2.5Methods and examplesExample 1We know:Labor standard per gallon=2.311 worker-hours per gallon of paintWorking-days per quarter=65 daysHours per day = 8 hoursAnnual hiring cost =$250 per workerAnnual layoff cost =$300 per workerAnnual inventory cost =$5 per unitOvertime cost =$9.5 per hour per workerSubcontracting price =$19.5 per gallonBack order cost =$ per periodLevel Capacity strategy:Average demand =(40000+57500+55000+52500)/4 =51250 Workers required =51250×2.311/(8×65) =228P.342。

THE EQUITABLE DISTRIBUTION OF THE BENEFITS FROMDECENTRALIZATION: A CHALLENGE FOR POWER SYSTEM DESIGNERSSarosh Talukdar Carnegie Mellon University.Introduction:Until recently, all power systems used centralized schemes for decision-makin g (plannin g and control). The restructurin g movement has sought to change this condition by decentralizin g the decision-makin g in selected parts of power systems, particularly, the generators. “Decentralization” means increasin g the number of decision-makers (a g ents) andthereby, decreasing the sizes of the problems to be solved by each agent. As a result, robustness and computability are improved: The g reater the number of agents, the smaller the effects of a failure in any one of them. And since thecomplexity of planning and control problems usually g rows super-linearly with their size, decomposing a few larg e problems into many smaller problems usually results in a reduction in a g g re g ate complexity. Examples of successful systems with a considerable deg ree of decentralization rang e from insect societies to the stock market.But there is a downside to decentralization. The technolo g y for its desi g n is woefully inadequate, especially in assuring decision-quality. Much of what exists is based on faith, anecdote and analog y. Consequently, attempts to decentralize systems often produce unfortunate and quite unexpected results, such as those obtained from decentralizing economic planning in Russia, and electric g eneration in California. I believe that three things are necessary in order to realize the full benefits of decentralizing the electric g rid, and to distribute these benefits equitably among all the participants. 1. Setting Optimal TargetsWhat are the maximum, possible benefits from decentralization? As the standard for comparison, we could use either an existing, centralized scheme or an ideal, centralized scheme (that makes optimum decisions based on perfect information). Suppose we choose the latter, and refer to its decisions as the g lobally optimum decisions. Then the “benefit assessment question” can be restated as follows: How close can the locally optimal (decentralized) decisions come to the globally optimal decisions?Networks like the electric g rid, have special properties that make them g ood candidates for decentralization. In such networks, I believe 1 that careful desig n can cause locally optimal decisions to come quite close to g lobally optimal decisions. (This is surprisin because in a decentralized scheme, each ag ent has access to only a limited amount of information, while in an ideal, centralized scheme, decisions are made with perfect and complete information.) In other words,decentralization can produce results far superior to any yet obtained from restructuring efforts.2. Testing and VerificationEng ineering desig n processes are characterized by very careful testing and verification. Every stage of the desig n process, from the development of a conceptual design to the creation of manufacturing plans, is separately tested and verified. Often, more effort is devoted to the development of tests than to the artifacts to be tested. Invariably, the tests reveal a few major flaws and a multitude of bugs, even in what seemed to be the very best of ideas. There is a 1 For the reasons see: “ Distributed Model Predictive Control”by Camponogara, Jia, Krogh and Talukdar, to appear in the Computer Society Magazine. 0-7803-7322-7/02/$17.00 © 2002 IEEEconsiderable literature on testin , and the journals that deal with it tend to have very stringent acceptance criteria. Economics, however, does not have such a tradition. Rather, economic artifacts, such as markets, are much more casually tested during their conception and development. Perhaps, markets are difficult to test. But whatever the reason, the lack of careful and systematic testing results in desig ns that are far more likely to be flawed. If we are to realize the full benefits of decentralization, we will need reliable testing and verification processes for the markets they contain. 3. SymmetryPower systems are quasi-repetitive: at anyinstant in any extended period of time, thecurrent conditions are likely to have beenduplicated at many previous instants, and arelikely to be duplicated at many future instants.In quasi-repetitive systems, agents can, throughexperiment and learning, develop strategies thatare effective in serving their selfish interests.Thus, giving only one class of agents, such asthe g enerators, enoug h autonomy to conductexperiments and learn from the results, willinevitably provide these a g ents with an advantage over the others in the system 2.If the benefits of decentralization are to beequitably distributed, all the ag ents must beprovided with equal opportunities toexperiment with, and learn, new strateg ies forbuying, selling and using energy. In particular,customers must be made full participants in thedecentralization, that is, provided with enoug hinformation and decision-making freedom toactively pursue their own interests, including ,2 For demonstrations of how very simple, evolutionarylearning by generators can cause prices to saturate--arrive at the upper limit for prices--see “CDNA forAuction Testing,” by Talukdar and Marshall, GridOperations and Planning Meeting (organized by EPRI),Washington DC, June 11, 2001.convenient interfaces for both buying and selling energy.SummaryPower systems are well suited to decentralization: I believe that locally optimal (decentralized) decisions can be made to come very close to, if not coincide with, g lobally optimal decisions (the best possible decisions from centralized processes). Current decentralization schemes do not realize this potential. To obtain the full benefits, we will need: a) convenient and reliable testing and verification processes, and b) symmetry in the decision-making freedom g iven to the ag ents in the system, and in particular, full customer participation.。

001、什么是Web2.0？▪"Web 2.0" refers to web development and web design that facilitates(促进) interactive（交互的）information sharing（信息共享）, interoperability(互操作性), user-centered design（以用户为中心的设计）and collaboration（合作）on the World Wide Web.▪ A Web 2.0 site allows its users to interact with other users or to change website content, in contrast to non-interactive websites where users are limited to the passive viewing of information that is provided to them.Web2.0 是相对Web1.0 的新的一类互联网应用的统称。

Web1.0 的主要特点在于用户通过浏览器获取信息。

Web2.0 则更注重用户的交互作用，用户既是网站内容的浏览者，也是网站内容的制造者。

002、web2.0特点？▪Web as platform (网络即平台)–NetScape V/S Google▪Harnessing Collective Intelligence （使用集体智慧）–User Information–User Visits–Wikipedia–Flickr–Tagging (Folksonomy v/s taxonomy)▪Blogging and RSS▪Data Next Intel Inside–Google's Web Crawl–Napster's Song Database–Ebay's Database of Products–Map Quest–Nav Teq▪End of Software Release Cycle （平常软件发布周期的终结）–Microsoft v/s Google–Microsoft's business model depends on everyone upgrading their computing environment every two to three years. Google's depends on everyone exploringwhat's new in their computing environment every day."▪Light Programming Models ()–AJAX–XML–RSS (Think Syndication not coordination)–Web Services–Open Source▪Software above level of a single device▪Rich User Experience （富用户体验）–Less Page Refresh–Windows Like Look n Feel003、长尾理论▪Long Tail–Leverage（影响力、杠杆作用）customer-self service and algorithmic(算法的) data management to reach entire web长尾理论（The Long Tail）是网络时代兴起的一种新理论，由美国人克里斯·安德森提出。

1、综合计划在哪些行业尤其重要?这些行业有哪些特征？What are some industries in which aggregate planning would be particularly important?综合计划对于一些制造业和服务业来说很有用。

制造业包括家具，所有耐用品，消费电子产品，纺织品，汽车和飞机。

服务行业包括餐馆和类似旅馆、汽车旅馆的酒店行业。

2、运用综合计划的行业有哪些特点?What are the characteristics of these industries that make them good candidates for aggregate planning?综合计划对于那些交付周期相对长和容量数额有限的行业非常有用。

这样的行业提供的终端产品或服务通常是由那些必须要运转一些制造行为的其他企业提供的输入信息组成。

3、综合计划策略之间的主要不同是什么？What are the main differences between the aggregate planning strategies?三个纯粹的总体规划策略是追赶策略，劳动力或产能的时间柔性策略，以及均衡策略。

这三种策略的主要区别是杠杆，即在综合计划期内，该参数被操纵以实现供需平等。

第一追逐赶略以使用机器或人员产能的形式作为杠杆。

在一个周期的基础上库存水平是非常低的，整个供应量的变化和工作压力是在一个恒定的状态，这可以增加管理成本。

第二种是从劳动力或产能的时间柔性，利用率的水平。

这一战略，就像之前的追赶计划，导致整个供应链的库存水平低。

它避免了裁员问题，但仍然需要一个灵活的劳动力，也可能导致机器设备利用率低。

第三个策略是在整个总规划期间保持一个恒定的输出率。

如果需求是高度可变的，这个计划会造成缺货或延期交货和其他时期的库存水平过高。

在这一战略中，并没有真正的同步需求与供应。

4、哪些行业或情况最适合使用追赶策略？哪些最适合使用柔性策略？哪些最适合使用均衡策略？What types of industries or situations are best suited to the chase strategy? The flexibility strategy? The level strategy?追赶策略适用于库存成本较高，而改变设备产能和劳动力数量成本较低的情况。

RoRoHoistable rampsPlanning the hoistable ramp Our aim is to design a hoistable ramp which is efficient, economic and safe, while fully meeting the specific operating requirements. The more information that can be given on these prerequisites, the greater the chance to find the optimum solution.Under the following headings informa-tion requirements can found before commencing the project. If these answers are available at the earlieststage possible, work will be saved during the later stages, gaining valuable time by shortening the lead time between initial contact and delivery.Ramp lengthIn order to establish the length of the ramp, we need to know the height measurement between the two deck levels, maximum knuckle angle (point of interchange between straight lines), and whether you require a specific gradient of the ramp.If the maximum knuckle angle is not known and/or gradient, please indicate the total vehicle height, height and ground clearances, wheelbase and overhang at front and rear. Where there is a need for higher vehicle speedsduring loading and unloading a shallower ramp gradient is often called for. The length of the ramp will then be longerClearance and typeof vehiclesClear height, gradient and height between decksP h o t o : d e n n i z @c o r s m a n .s ethan that calculated only on the basis of geometrical clearance at the knuckles. To minimize the ramp length, we often construct the ramp with an s-shaped profile, with a shallower gradient at each end of the ramp.Ramp widthDescribe the internal cargo flow onto and off the ramp. Indicate the required number and width of lanes on the ramp. Typical clear width values: 3,5 m forsingle-lane and 6,0 m for dual-lane trailer traffic and 3,0 m for single-car lane and 5,0 m for dual-car lane.LoadingsIn order to dimension the steel structure with the required strength and minimum weight we need to know the following: What kind of vehicles will be driven over the ramp? What are the axle loading and wheel print area? How many axles are there and how far apart are they?How much total simultaneous loading must the ramp withstand, i.e. what is the maximum number of vehicles likely to be found on the ramp at the same time during loading and unloading? What is the maximum total weight to be supported on the ramp when it is being raised?Interface between ramp and ship When you design the hull in the area of the ramp, adequate space must be reserved for the ramp and its associated equipment.The ramp requires a longi t udinal space approximately (as a rule of the thumb) eight times the height between the decks. The lateral space consists of the clear driveway plus up to 500 mm at each side of the ramp depending on size. This space is needed for railings, sealing system and operating equipment. Contact us early in the planning stages if you require a more precise estimate of the space.you can easily switch between the two locations (c).When the clear height on the ramp is less than that dictated for the lower deck, a two-piece ramp is often the best solution (d).The opening is smaller and the support pillars may be omitted. The ramp may in all different con fi gur a t ions be equipped with or prepared for installation of drencher-piping and electric lightning.Sealing optionsThere are three alternatives – no sealing, watertight sealings or gastight sealing. On request, the sealings can also be combined with fire protection; the seal will then be of fire-retardent material.Control optionsTwo different systems are available, manual and automated.Hydraulic capacityThe determining factors in the dimen-sion i ng of the capacity of the hydraulic system are the size of the ramp, total load when raising, and the required speed of opening and closing.A typical time for opening or closing is 2 to 5 minutes, excluding opening and closing of the securing devices. The shorter the time, the more costly the required hydraulics.Clearly, there is also a limit to thetechnical feasibility. An indication should be given of the maximum and minimum ambient temperatures in which the hydraulic system is to operate.Regulatory bodiesPlease specify which demands are to be met by the equipment. In other words, which classification societies, national authorities and other regulations (e.g. IMO) are to be satisfied.Normally, the ramp is classified as a part of the ship’s deck. Let us know if you also require a lifting gear certificate.OptionsOn the right we show the equipment or accessories which require your decision, also optional equipment which may be added to the ramp.These should be studied point by point when making an initial evaluation, based upon the particular operating conditions.Ramp arrangement optionsA one-piece ramp is the natural choice. Choose between three hinge locations: hinged at one end on the upper deck (a), or on the lower deck (b), or hinged at both ends on the upper deck whereReserve space for ancillary ramp equipmentClear width500 mmabcd•Automated control systemWhereby pressing and holding a single button will initiate and complete the whole opening or closing sequence.•Manual control systemEach step in the operation is controlled by hand-operated hydraulic valves.The greater the degree of system automation, the easier and faster the operation. An automated system will be particularly cost effective on shorter runs where there is a need for faster loading and unloading. The manual controlsystem is in practice restricted to simple ramps: non-tight and of low degree of complexity.Operating optionsTwo different systems are available:• Direct hydraulic/electric cylinders •Wires by hydraulic/electric jigger-winchThe normal choice involves wire ropes anchored at the deck head and operated by hydraulic/electric jigger-winch mounted within the ramp structure.To accommodate transverse forces during operation, the ramp is guided by ship-mounted guides. For a ramp less than around 30 meters in length, choose hydraulic/electric cylinders acting directly on the ramp. This is the most cost effective and reliable solution provided that there is sufficient space. When the ramp is longer than 30 m or so, choosewire ropes operated by jigger-winch.Support linksWires by jigger-winchFixed support stoolsDirect hydraulic cylindersHandrail optionsHandrails are available in three versions which can all be combined on the same ramp.• Fixed to the ramp.•Portable and stowed on board during the voyage.•Automatically foldable into a recess alongside the ramp when it is in the closed position.The simplest and most cost effective version is the fixed one.However, if handrails might impede the cargo, equipment or gangways, the portable or automatically foldable version is the natural choice.Automatically foldable handrailsFixed handrailsPortable handrails Steel structure with girders below the top plate1 Herringbone2-3 Anti-slip coating4 Expanded metal5 Nelson studsSteel structure with high side girdersThe main section of the rampThere are two types of steel structure. For short ramps and low loads you should choose a steel structure with girders below the top plate and separate railings. For long ramps and high loads, choose a steel structure with high side girders which also serve as railings.Anti-slip optionsThree main anti-slip systems are available.1) Welded square bars in a herringbone or straight pattern provide a robust skid- resistant but with an uneven surface.2) The second alternative is polyurethane resin based anti-slip system dressed with high-grade abrasion resistant aggregates, which provides a high friction and an even surface.3) The third alternative is anti-slip paint consisting of epoxy paint dressed withresistance friction material, which provides a surface suitable for light load such as private cars.4) Expanded metal provides an even running surface with high friction at lower cost but the design is more prone to mechanical damage and wear, all of which may lead to higher maintenance costs.5) The design of Nelson studs is robust and the running surface is even although the friction is lower than with the other types.Support optionsSupports are used for carrying the weight of the ramp plus load during loading and unloading. Two types are available. Fixed stools offer the simplest and best solution, provided that there is sufficient space and the cargo flow is not impeded. In all other cases, choose support links positioned at each side of the ramp, at mid-length and anchored to the deck head.The MacGregor standard for hoistable rampsOver the years MacGregor hasdesigned and manufactured a great variety of hoistable ramps for different types of ships. We therefore promise that your ramp will meet your needs in terms of quality, efficiency, security and overall economy.Yet it will be standardised in all major functions. In other words, you will be supplied with well-proven equipment which is easy to maintain for long-term trouble-free operation and easy to repair in the event of an accident. We believe in high quality in every respect.Steel structure qualityThe ramp is designed as a flat top plate with an open web construction to meet the demands for torsional strength due to the movements of the hull or heel of the ship. High tensile steel is used throughout the ramp as standard. Fixed wheel kerbs are fitted at each side of the driveway and fixed or foldable handrails wherever possible. Elsewhere, portable handrails are employed.Open web construction Quality of fittingsShafts and pins exposed to the weather are of stainless steel. Cylinders are fitted with spherical plain bearings.Sealing and securing qualityThe team of MacGregor engineers have spared no effort in developing an efficient and secure watertight seal. The result is a simple but high-performance design. A rubber packing is placed in and around the perimeter of the opening of the hull. When closing the ramp the rubber is pressed against compression bars made of stainless steel. These have a very smooth surface to guard against any penetration of water.The ramp is secured in the closed watertight position by hydraulically operated cleat mechanisms at each side of the ramp. They are well-proven MacGregor innovations which can be relied upon.Safety qualityBeing the market leader, MacGregor’s ship experts are invited by national authorities and classification societies to use its expertise and experience, gained from numerous installations, to help develop and evaluate new rules and regulations.Your hoistable ramp will incorporate a number of items of safety equipment regulated by classification societies and authorities.When the ramp is closed and cleated, the true status is confirmed by the indicator lamps both at the operating panel and the bridge panel. Customdesigned load control valves are normally fitted directly on the cylinders. This will prevent the ramp from falling down in the event of hydraulic or electrical failure.Only high quality components ofmarine design from approved suppliersare used in MacGregor equipment.Bridge panelNon-foldable flapFoldable flapCleat mechanismFlap optionsSelect one of the two flap designs. One is stowed horizontal in the raised position. The other is stowed upright, forming a barrier at right angles to the ramp with a free end.Rubber packingCompression barRubber packingCompression barSliding seal designMacGregor Sweden ABRoRoP.O. Box 4113,SE-400 40 GothenburgSwedenTel. +46 31 85 07 00***************************************************MacGregor is the world’s leading brand of engineering solutions and services for handling marine cargoes and offshore loads. MacGregor products serve the maritime transportation, offshore and naval logistics markets, in ports and terminals as well as on board ships. Our cargo flow solutions integrate cargo access, stowage, care and handling functions to suit a particular ship’s cargo profile. This benefits its productivity, environmental impact and profitable service lifetime.MacGregor is part of Cargotec. Cargotec’s class B shared are quoted on NASDAQ OMX Helsinki.Published by MacGregor. Copyright © MacGregor January 2014. All rights reserved. No part of this publication may be reproduced, stored, photocopied, recorded or transmitted without permis-sion of the copyright owner.。

运营管理的第13章True / False Questions1. Aggregate planning is intermediate-range capacity planning that typically covers a time horizon of one to three months. FALSEDifficulty: MediumTLO: 1Taxonomy: Knowledge2. The goal of aggregate planning is to achieve a production plan that attempts to balance the organization's resources and meet expected demand.TRUEDifficulty: EasyTLO: 1Taxonomy: Knowledge3. The assignment of work to specific machines and people are examples of aggregate planning.FALSEDifficulty: MediumTLO: 1Taxonomy: Knowledge4. The output from aggregate planning is a detailed business plan covering the next 2 to 12 months.FALSEDifficulty: EasyTLO: 1Taxonomy: Knowledge5. Demand can be altered in aggregate planning by promotion and producing additional product using overtime.FALSEDifficulty: HardTLO: 2Taxonomy: Knowledge6. Capacity can be modified in aggregate planning by promotion and producing additional product using overtime. FALSEDifficulty: HardTLO: 2Taxonomy: Knowledge7. A level capacity strategy is also known as a chase demand strategyFALSEDifficulty: EasyTLO: 2Taxonomy: Knowledge8. Ultimately the overriding factor in choosing a strategy in aggregate planning is overall cost. TRUEDifficulty: HardTLO: 2Taxonomy: Knowledge9. Disaggregating an aggregate plan leads to a master schedule.TRUEDifficulty: MediumTLO: 1Taxonomy: Knowledge10. After the first period of the planning horizon, available-to-promise is computed only for those periods in which there is an MPS quantity.TRUEDifficulty: MediumTLO: 1Taxonomy: KnowledgeMultiple Choice Questions1. Which of the following best describes aggregate planning?A. the link between intermediate term planning and short term operating decisionsB. a collection of objective planning toolsC. make or buy decisionsD. an attempt to respond to predicted demand within the constraints set by product, process and location decisionsE. manpower planningDifficulty: EasyTLO: 1Taxonomy: Knowledge2. Aggregate planning is capacity planning for:A. the long rangeB. the intermediate rangeC. the short rangeD. typically one to three monthsE. typically one or more yearsDifficulty: EasyTLO: 1Taxonomy: Knowledge3. One area to which aggregate planning decisions relate is:A. job sequencingB. customer order quantitiesC. inventory levelsD. locationE. layoutDifficulty: HardTLO: 1Taxonomy: Knowledge4. In doing "aggregate planning" for a firm producing paint, the aggregate planners would most likely deal with:A. just gallons of paint, without concern for the different colors and sizesB. gallons of paint, but be concerned with the different colors to be producedC. gallons, quarts, pints, and all the different sizes to be producedD. all the different sizes and all the different colors by sizeE. none of the aboveDifficulty: MediumTLO: 2Taxonomy: Knowledge5. One option for altering the pattern of demand is:A. backordersB. overtimeC. part-time workersD. inventoriesE. subcontractingDifficulty: MediumTLO: 2Taxonomy: Knowledge6. In practice, the more commonly used techniques for aggregate planning are:A. mathematical techniquesB. informal trial-and-error techniquesC. (a) and (b) about equallyD. simulation modelsE. linear programming optimizationDifficulty: EasyTLO: 3Taxonomy: Knowledge7. Inventory information for firm ABC:What is the expected inventory at the end of April, 1999?A. 350B. 250C. 150D. 50E. none of the aboveAACSB: ASDifficulty: EasyTLO: 4Taxonomy: Application8. The direct result of disaggregating the aggregate plan is the:A. marketing planB. production planC. rough-cut capacity planD. master scheduleE. material requirements planDifficulty: MediumTLO: 1Taxonomy: Knowledge9. That portion of projected inventory which enables marketing to make realistic commitments about delivery dates for new orders is:A. beginning inventoryB. safety stock inventoryC. available-to-promise inventoryD. high margin inventoryE. none of the aboveAACSB: CADifficulty: EasyTLO: 1Taxonomy: Knowledge10. Proactive and Reactive aggregate planning strategies are best associated with:A. Input and OutputB. Make and BuyC. Quantitative and QualitativeD. Exact and ApproximateE. Demand and Capacity optionsDifficulty: MediumTLO: 2Taxonomy: KnowledgeEssay Questions1. A manager has prepared a forecast of expected aggregate demand for the next six months. Develop an aggregate plan to meet this demand given this additional information: A level production rate of 100 units per month will be used. Backorders are allowed, and they are charged at the rate of $8 per unit per month. Inventory holding costs are $1 per unit per month in ending inventory. Determine the cost of this plan if regular time cost is $20 per unit and beginning inventory is zero.The aggregate plan should look like this:With costs as follows:Total cost of this plan is $12,200.Feedback: Production remains constant in a level aggregate plan.AACSB: ASDifficulty: MediumTLO: 4Taxonomy: Application2. Prepare a master schedule based on the following information:Currently there are 145 units in inventory. Policy calls for a fixed order quantity of 250 units.Feedback: There are units available-to-promise in several time periodsAACSB: ASDifficulty: MediumTLO: 4Taxonomy: Application3.A. What is total regular time capacity?1,680 unitsFeedback: Multiply the per-period regular-time capacity (280) by six. AACSB: ASDifficulty: MediumTLO: 4Taxonomy: ApplicationB. How should overtime capacity be utilized?Refer To: 13-6540 units each in periods 3, 4, and 5Feedback: This represents the best use of overtime capacityAACSB: ASDifficulty: MediumTLO: 4Taxonomy: ApplicationC. What are total regular time costs?Refer To: 13-65$33,600Feedback: Multiply units produced on regular time by their regular time cost.AACSB: ASDifficulty: MediumTLO: 4Taxonomy: Application4. A firm has 56 units of product X on hand. Forecasts of demand are for 20 units per week. An MPS quantity of 100 units is planned to arrive in period 3. Customer orders are 24 for period 1,18 for period 2, and 15 for period 3.A. What is the projected on hand inventory at the end of period 2?A. 14B. 32C. 12D. 20E. impossible to say without additional informationFeedback: Subtract the week 2 forecast (20) from week 1 projected ending on-hand (32). AACSB: ASDifficulty: MediumTLO: 4Taxonomy: ApplicationB. What quantity is available for commitment to new customers prior to the receipt of the MPS quantity in week 3?A. 14B. 32C. 12D. 20E. impossible to say without additional information.Feedback: There are 56 units in beginning inventory, and booked orders for 42 units until the next MPS quantity receipt. AACSB: ASDifficulty: MediumTLO: 4Taxonomy: Application。

Current Planning SolutionsIntroductionIn any organization or project, planning plays a crucial role in achieving goals efficiently and effectively. Planning involves setting objectives, determining necessary steps to reach those objectives, allocating resources, and establishing timelines. In this document, we will explore the current planning solutions used in various industries and the benefits they provide.Traditional Planning MethodsHistorically, planning was mnly done using traditional methods, such as pen and paper or spreadsheets. While these methods were effective to some extent, they had limitations in terms of collaboration, version control, and accessibility. As technology advanced, organizations beganadopting more sophisticated planning solutions to overcome these challenges.Integrated Planning SoftwareToday, many organizations rely on integrated planning software tools to streamline their planning processes. These software tools offer a range of features and functionalities that enhance collaboration, improve accuracy, and incre ase productivity. Let’s explore some popular planning software solutions in use today:1. Microsoft ProjectMicrosoft Project is one of the most widely used planning software worldwide. It allows users to create and manage project plans, assign resources, track progress, and generate reports. With its intuitive interface and robust features, Microsoft Project enables project managers to effectively plan and execute projects of any scale.Trello is a popular visual planning tool used for managing projects and workflows. It uses a Kanban-style board and allows users to create and organize tasks using cards. With its user-friendly interface, drag-and-drop functionality, and real-time collaboration features, Trello simplifies the planning process and improves team productivity.3. AsanaAsana is a comprehensive project management tool that offers powerful planning capabilities. It enables users to create tasks, set due dates, assign responsibilities, and track progress. With features like task dependencies, customizable workflows, and integrations with other tools, Asana provides a centralized platform for effective planning and project management.JIRA is primarily known as a software development and issue tracking tool, but it also offers robust planning features. It allows users to create and manage tasks, assign them to team members, and track their progress. JIRA’s agile-focused planning capabilities, such as Scrum and Kanban boards, make it a preferred choice for software development teams.Benefits of Planning SolutionsImplementing planning solutions brings several benefits to organizations:1.Improved Efficiency: Planning software automates manualtasks, eliminates redundant processes, and improves the overallefficiency of planning activities.2.Enhanced Collaboration: Planning tools enable real-time collaboration, allowing team members to work together seamlessly, share updates, and communicate effectively.3.Increased Accuracy: Planning solutions provide better accuracy in forecasting timelines, resource requirements, and potential risks, leading to better decision-making.4.Better Resource Allocation: With planning software, organizations can allocate resources more effectively, ensuring that they are utilized optimally and reducing unnecessary costs.5.Greater Visibility: Planning tools offer dashboards and reporting capabilities that provide an overview of project progress, enabling stakeholders to have real-time visibility into the status of initiatives.6.Improved Risk Management: Planning solutions help identify potential risks in advance, enabling organizations todevelop strategies to mitigate those risks and ensure successfulproject delivery.ConclusionIn conclusion, current planning solutions have revolutionized the way organizations approach planning. Integrated planning software tools provide a wide array of features that enhance collaboration, improve efficiency, and increase accuracy. By leveraging these solutions, organizations can streamline their planning processes, allocate resources effectively, and achieve their goals more efficiently.。

Chapter 8Aggregate Planning in the Supply ChainTrue/False1.The goal of aggregate planning is to satisfy demand in a way that minimizes profit.Answer: FalseDifficulty: Easy2.Aggregate planning is a process by which a company determines levels of capacity,production, subcontracting, inventory, stockouts, and even pricing over a specified time horizon.Answer: TrueDifficulty: Moderate3.Aggregate planning solves problems involving aggregate decisions rather than stockkeeping unit (SKU) level decisions.Answer: TrueDifficulty: Easy4.Traditionally, much of aggregate planning is focused within an enterprise and may notalways be seen as a part of supply chain management.Answer: TrueDifficulty: Moderate5.Aggregate planning is an important supply chain issue because, to be effective, itrequires inputs from throughout the supply chain, but its results have little impact onthe supply chain.Answer: FalseDifficulty: Moderate6.Short-term production serves as a broad blueprint for operations and establishes theparameters within which aggregate planning decisions are made.Answer: FalseDifficulty: Easy7.The aggregate planning problem is concerned with determining the production level,inventory level, and capacity level (internal and outsourced) for each period thatmaximizes the firm’s profit over the planning horizon.Answer: TrueDifficulty: Moderate8.To create an aggregate plan, a company must specify the planning horizon for the planand the duration of each period within the planning horizon.Answer: TrueDifficulty: Easy9. A planning horizon is usually between three and five years.Answer: FalseDifficulty: Moderate10. A poor aggregate plan can result in improved sales and profits if the available inventoryand capacity are unable to meet demand.Answer: FalseDifficulty: Easy11. A poor aggregate plan may result in a large amount of excess inventory and capacity,thereby raising costs.Answer: TrueDifficulty: Moderate12.The aggregate planner must make a trade-off between capacity, inventory, and backlogcosts.Answer: TrueDifficulty: Moderate13.An aggregate plan that increases one cost typically results in the increase of the othertwo.Answer: FalseDifficulty: Moderate14.The time flexible strategy is where the production rate is synchronized with the demandrate by varying machine capacity or hiring and laying off employees as the demand rate varies.Answer: FalseDifficulty: Hard15.The time flexible strategy is where workforce (capacity) is kept stable but the number ofhours worked is varied over time in an effort to synchronize production with demand.Answer: TrueDifficulty: Moderate16.The mixed strategy is where a stable machine capacity and workforce are maintainedwith a constant output rate with inventory levels fluctuating over time.Answer: FalseDifficulty: Hard17.Most strategies that an aggregate planner actually uses are in combination, and arereferred to as mixed strategies.Answer: TrueDifficulty: Easy18. A highly effective tool for a company to use when it tries to maximize profits while beingsubjected to a series of constraints is aggregate programming.Answer: FalseDifficulty: Moderate19.To improve the quality of these aggregate plans, forecast errors must be taken intoaccount when formulating aggregate plans.Answer: TrueDifficulty: Moderate20.Forecasting errors are dealt with in aggregate plans using either safety backlog or safetycapacity.Answer: FalseDifficulty: Moderate21.Safety inventory is defined as inventory held to satisfy demand that is higher thanforecasted.Answer: TrueDifficulty: Easy22.Safety capacity is defined as capacity used to satisfy demand that is lower thanforecasted.Answer: FalseDifficulty: Easypanies should work with downstream partners to produce forecasts and withupstream partners to determine constraints when doing aggregate planning.Answer: TrueDifficulty: Easy24.The aggregate plan should be viewed primarily as an in-house tool that does not need tobe communicated to supply chain partners.Answer: FalseDifficulty: Easy25.Given that forecasts are always wrong to some degree, the aggregate plan needs tohave some flexibility built into it if it is to be useful.Answer: TrueDifficulty: Moderate26. A manager should perform sensitivity analysis on the inputs into an aggregate plan tochoose the best solution for the range of possibilities that could occur.Answer: TrueDifficulty: Moderate27.As inputs into the aggregate plan change, managers do not need to make changes to theaggregate plan.Answer: FalseDifficulty: Easy28.As capacity utilization increases, it becomes less important to perform aggregateplanning.Answer: FalseDifficulty: ModerateMultiple Choice1.The process by which a company determines levels of capacity, production,subcontracting, inventory, stockouts, and even pricing over a specified time horizon isa.aggregate planning.b.detail planning.c.inventory planning.d.sales planning.e.all of the aboveAnswer: aDifficulty: Moderate2.The goal of aggregate planning is toa.dissatisfy customers in a way that maximizes profit.b.dissatisfy customers in a way that minimizes profit.c.satisfy demand in a way that maximizes profit.d.satisfy demand in a way that minimizes profit.e.none of the aboveAnswer: cDifficulty: Easy3.Aggregate planning solves problems involvinga.aggregate decisions and stock keeping unit (SKU) level decisions.b.aggregate decisions or stock keeping unit (SKU) level decisions.c.aggregate decisions rather than stock keeping unit (SKU) level decisions.d.stock keeping unit (SKU) level decisions rather than aggregate decisions.e. b and c onlyAnswer: cDifficulty: Easy4.Aggregate planning, to be effective, requires inputs froma.all customers.b.all departments.c.all suppliers.d.throughout the supply chain.e.throughout the company.Answer: dDifficulty: Moderate5.Much of aggregate planning has traditionally been focuseda.on short-term production scheduling.b.on customer relationship management.c.within an enterprise.d.beyond enterprise boundaries.e.all of the aboveAnswer: cDifficulty: Moderate6.Which of the following are not operational parameters the aggregate planner isconcerned witha.production rateb.workforcec.overtimed.backorderse.inventory on handAnswer: dDifficulty: Moderate7.The operational parameter concerned with the number of units completed per unit time(such as per week or per month) isa.production rate.b.workforce.c.overtime.d.backlog.e.inventory on hand.Answer: aDifficulty: Easy8.The operational parameter concerned with the number of workers/units of capacityneeded for production isa.production rate.b.workforce.c.overtime.d.backlog.e.inventory on hand.Answer: bDifficulty: Easy9.The operational parameter concerned with the amount of overtime production plannedisa.production rate.b.workforce.c.overtime.d.backlog.e.inventory on hand.Answer: cDifficulty: Easy10.The operational parameter concerned with demand not satisfied in the period in whichit arises, but carried over to future periods isa.production rate.b.workforce.c.overtime.d.backlog.e.inventory on hand.Answer: dDifficulty: Easy11.The operational parameter concerned with the planned inventory carried over thevarious periods in the planning horizon isa.production rate.b.workforce.c.overtime.d.backlog.e.inventory on hand.Answer: eDifficulty: Easy12.The operational parameter concerned with the number of units of machine capacityneeded for production isa.machine capacity level.b.subcontracting.c.overtime.d.backlog.e.inventory on hand.Answer: aDifficulty: Easy13.The operational parameter concerned with the subcontracted capacity required overthe planning horizon isa.machine capacity level.b.subcontracting.c.overtime.d.backlog.e.inventory on hand.Answer: cDifficulty: Easy14.The aggregate plana.serves as a broad blueprint for operations.b.establishes the parameters within which short-term production and distributiondecisions are made.c.allows the supply chain to alter capacity allocations and change supply contracts.d.all of the abovee. b and c onlyAnswer: dDifficulty: Moderate15.Aggregate planning is concerned with determininga.the production level, sales level, and capacity for each period.b.the demand level, inventory level, and capacity for each period.c.the production level, inventory level, and capacity for each period.d.the production level, staffing level, and capacity for each period.e.none of the aboveAnswer: cDifficulty: Moderate16.To create an aggregate plan, a company must specifya.the planning horizon for the plan.b.the duration of each period within the planning horizon.c.key information required.d.all of the abovee. a and b onlyAnswer: dDifficulty: Moderate17.The planning horizon isa.the time period over which the aggregate plan is to produce a solution.b.the duration of each time period in the aggregate plan.c.the length of time required to produce the aggregate plan.d.the solution to the aggregate plan.e.none of the aboveAnswer: aDifficulty: Easy18.The length of the planning horizon is usually betweena.one and three months.b.three and eighteen months.c.one and three years.d.three and five years.e.none of the aboveAnswer: bDifficulty: Moderate19.Which of the following is not information needed by the aggregate plannera.demand forecast for each period in the planning horizonb.production costsbor costsd.cost of subcontracting productione.cost of changing the demand forecastAnswer: eDifficulty: Moderate20.The cost of changing capacity includes thea.cost of adding machine capacity.b.cost of reducing machine capacity.c.cost of hiring workforce.d.cost of laying off workforce.e.all of the aboveAnswer: eDifficulty: Easy21.Which of the following is not a cost of changing capacitya.cost of adding machine capacityb.cost of hiring workforcec.cost of laying off workforced.cost of overtimee.cost of reducing machine capacityAnswer: dDifficulty: Moderate22.Which of the following is not a constraint the aggregate planner needs to considera.limits on stockouts and backlogsb.limits on overtimec.limits on sales commissionsd.limits on layoffse.limits on capital availableAnswer: cDifficulty: Moderate23. A poor aggregate plan can result ina.appropriate inventory levels.b.efficient use of capacity.c.better sales and lost profits.d.lost sales and lost profits.e.lost sales and better profits.Answer: dDifficulty: Hard24.The fundamental trade-offs available to an aggregate planner are betweena.capability, inventory, and backlog costs.b.capability, inventory, and sales costs.c.capacity, inventory, and backlog costs.d.capacity, inventory, and sales costs.e.none of the aboveAnswer: cDifficulty: Easy25.Which of the following is not a distinct aggregate planning strategy for achievingbalance between capacity, inventory, and backlog costsa.adjustable strategyb.Chase strategyc.level strategyd.mixed strategye.time flexible strategyAnswer: aDifficulty: Easy26.The strategy where the production rate is synchronized with the demand rate by varyingmachine capacity or hiring and laying off employees as the demand rate varies is thea.adjustable strategy.b.Chase strategy.c.level strategy.d.mixed strategy.e.time flexible strategy.Answer: bDifficulty: Moderate27.The strategy where workforce (capacity) is kept stable but the number of hours workedis varied over time in an effort to synchronize production with demand is thea.adjustable strategy.b.Chase strategy.c.level strategy.d.mixed strategy.e.time flexible strategy.Answer: eDifficulty: Moderate28.The strategy where a stable machine capacity and workforce are maintained with aconstant output rate, with inventory levels fluctuating over time, is thea.adjustable strategy.b.Chase strategy.c.level strategy.d.mixed strategy.e.time flexible strategy.Answer: cDifficulty: Hard29.Most strategies that an aggregate planner actually uses are in combination and arereferred to as thea.adjustable strategy.b.Chase strategy.c.level strategy.d.mixed strategy.e.time flexible strategy.Answer: dDifficulty: Easy30. A highly effective tool for a company to use when it tries to maximize profits while beingsubjected to a series of constraints isa.aggregate programming.b.distribution programming.c.production programming.d.linear programming.e.manufacturing programming.Answer: dDifficulty: Moderate31.When formulating aggregate plans,a.forecast errors have no impact.b.forecast errors must be taken into account.c.forecast accuracy is assumed.d.forecast accuracy is not a factor.e.none of the aboveAnswer: bDifficulty: Moderate32.Forecasting errors are dealt with usinga.safety backlog.b.safety capacity.c.safety inventory.d.all of the abovee. b and c onlyAnswer: eDifficulty: Moderate33.Inventory held to satisfy demand that is higher than forecasted isa.safety backlog.b.safety capacity.c.safety inventory.d.safety sales.e.safety workforce.Answer: cDifficulty: Easy34.Capacity used to satisfy demand that is higher than forecasted isa.safety backlog.b.safety capacity.c.safety inventory.d.safety sales.e.safety workforce.Answer: bDifficulty: Easy35.Which of the following is an approach a company can use to create a buffer for forecasterror using safety inventorya.overtimeb.carry extra workforce permanentlyc.build and carry extra inventoriesd.subcontractinge.purchase capacity or product from an open or spot marketAnswer: aDifficulty: Easy36.Which of the following is not an approach a company can use to create a buffer forforecast error using safety capacitya.overtimeb.carry extra workforce permanentlyc.build and carry extra inventoriesd.subcontractinge.purchase capacity or product from an open or spot marketAnswer: cDifficulty: Easy37.Aggregate planning should consider information froma.only the enterprise as its breadth of scope.b.downstream partners to produce forecasts.c.upstream partners to determine constraints.d.all of the abovee. b and c onlyAnswer: dDifficulty: Easy38.The quality of the aggregate plan can be improved by using information froma.only the local firm.b.only downstream partners.c.only upstream partners.d.all parts of the supply chain.e.none of the aboveAnswer: bDifficulty: Moderate39.The aggregate plan should be communicated toa.only the local firm.b.only downstream partners.c.only upstream partners.d.all supply chain partners who will be affected by it.e.none of the aboveAnswer: cDifficulty: Moderate40.The aggregate plan needs toa.be a final product because changes are disruptive to the supply chain.b.be considered fixed because forecasts are usually accurate.c.have some flexibility built into it because forecasts are always wrong.d.have some flexibility built into it because forecasts are usually right.e.none of the aboveAnswer: cDifficulty: Moderate41.How frequently should the aggregate plan be reruna.weeklyb.monthlyc.every 3 to 8 monthsd.as inputs to the aggregate plan changee.neverAnswer: dDifficulty: Hard42.As capacity utilization increases,a.it becomes less important to perform aggregate planning.b.it becomes more important to perform aggregate planning.c.it does not affect the importance of performing aggregate planning.d.it lessens the importance of aggregate planning.e.none of the aboveAnswer: bDifficulty: ModerateEssay/Problems1.Discuss the primary objective and operational parameters of aggregate planning.Answer: The goal of aggregate planning is to satisfy demand in a way that maximizesprofit. Aggregate planning is a process by which a company determines levels ofcapacity, production, subcontracting, inventory, stockouts, and even pricing over aspecified time horizon. The aggregate planner’s main objective is to identify thefollowing operational parameters over the specified time horizon:Production rate: the number of units completed per unit time (such as per week or per month).Workforce: the number of workers/units of capacity needed for production.Overtime: the amount of overtime production planned.Machine capacity level: the number of units of machine capacity needed for production.Subcontracting: the subcontracted capacity required over the planning horizon.Backlog: demand not satisfied in the period in which it arises but carried over to future periods.Inventory on hand: the planned inventory carried over the various periods in theplanning horizon.The aggregate plan serves as a broad blueprint for operations and establishes theparameters within which short-term production and distribution decisions are made.The aggregate plan allows the supply chain to alter capacity allocations and changesupply contracts.Difficulty: Moderate2.Discuss the information required for aggregate planning.Answer: An aggregate planner requires the following information:Demand forecast F t for each Period t in the planning horizon that extends over TperiodsProduction costsLabor costs, regular time ($/hour), and overtime costs ($/hour)Cost of subcontracting production ($/unit or $/hour)Cost of changing capacity; specifically, cost of hiring/laying off workforce ($/worker)and cost of adding or reducing machine capacity ($/machine)Labor/machine hours required per unitInventory holding cost ($/unit/period)Stockout or backlog cost ($/unit/period)Constraints:Limits on overtimeLimits on layoffsLimits on capital availableLimits on stockouts and backlogsConstraints from suppliers to the enterpriseThis information is used to create an aggregate plan that in turn helps a company make the following determinations:Production quantity from regular time, overtime, and subcontracted time: usedto determine number of workers and supplier purchase levels.Inventory held: used to determine how much warehouse space and workingcapital is needed.Backlog/stockout quantity: used to determine what the customer service levelswill be.Workforce hired/laid off: used to determine any labor issues that will beencountered.Machine capacity increase/decrease: used to determine if new productionequipment needs to be purchased or idled.The quality of an aggregate plan has a significant impact on the profitability of a firm. A poor aggregate plan can result in lost sales and lost profits if the available inventory and capacity are unable to meet demand. A poor aggregate plan may also result in a largeamount of excess inventory and capacity, thereby raising costs. Therefore, aggregateplanning is a very important tool in helping a supply chain maximize profitability.Difficulty: Hard3.Explain the basic strategies that an aggregate planner has available to balance thevarious costs and meet demand.Answer: There are essentially three distinct aggregate planning strategies for achieving balance between these costs. These strategies involve trade-offs between capitalinvestment, workforce size, work hours, inventory, and backlogs/lost sales. Moststrategies that a planner actually uses are a combination of these three and are referred to as mixed strategies. The three strategies are as follows:1. Chase strategy—using capacity as the lever: With this strategy, the production rate issynchronized with the demand rate by varying machine capacity or hiring and laying off employees as the demand rate varies. In practice, achieving this synchronization can be very problematic because of the difficulty in varying capacity and workforce on shortnotice. This strategy can be expensive to implement if the cost of varying machine orlabor capacity over time is high. It can also have a significant negative impact on themorale of the workforce. The Chase strategy results in low levels of inventory in thesupply chain and high levels of change in capacity and workforce. It should be usedwhen the cost of carrying inventory is very expensive and costs to change levels ofmachine and labor capacity are low.2. Time flexibility strategy—using utilization as the lever: This strategy may be used ifthere is excess machine capacity ., if machines are not used twenty four hours a day,seven days a week). In this case, the workforce (capacity) is kept stable but the number of hours worked is varied over time in an effort to synchronize production with demand.A planner can use variable amounts of overtime or a flexible schedule to achieve thissynchronization. Although this strategy does require that the workforce be flexible, itavoids some of the problems associated with the Chase strategy, most notably changing the size of the workforce. This strategy results in low levels of inventory but with lower average utilization. It should be used when inventory carrying costs are relatively highand machine capacity is relatively inexpensive.3. Level strategy—using inventory as the lever: With this strategy, a stable machinecapacity and workforce are maintained with a constant output rate. Shortages andsurpluses result in inventory levels fluctuating over time. Here production is notsynchronized with demand. Either inventories are built up in anticipation of futuredemand or backlogs are carried over from high- to low-demand periods. Employeesbenefit from stable working conditions. A drawback associated with this strategy is that large inventories may accumulate and customer orders may be delayed. This strategykeeps capacity and costs of changing capacity relatively low. It should be used wheninventory carrying and backlog costs are relatively low.Difficulty: Moderate4.Discuss key issues to be considered when implementing aggregate planning.Answer: 1. Think beyond the enterprise to the entire supply chain. Most aggregateplanning done today takes only the enterprise as its breadth of scope. However, thereare many factors outside the enterprise throughout the supply chain that candramatically impact the optimal aggregate plan. Therefore, avoid the trap of onlythinking about your enterprise when aggregate planning. Work with partnersdownstream to produce forecasts, with upstream partners to determine constraints,and with any other supply chain entities that can improve the quality of the inputs into the aggregate plan. As the plan is only as good as the quality of the inputs, using thesupply chain to increase the quality of the inputs will greatly improve the quality of the aggregate plan. Also make sure to communicate the aggregate plan to all supply chainpartners who will be affected by it.2. Make plans flexible because forecasts are always wrong. Aggregate plans are basedon forecasts of future demand. Given that these forecasts are always wrong to somedegree, the aggregate plan needs to have some flexibility built into it if it is to be useful.By building flexibility into the plan, when future demand changes, or other changesoccur, such as increases in costs, the plan can appropriately adjust to handle the new situation. A manager should perform sensitivity analysis on the inputs into an aggregate plan. Using sensitivity analysis on the inputs into the aggregate plan will enable the planner to choose the best solution for the range of possibilities that could occur.3. Rerun the aggregate plan as new data emerges. Aggregate plans provide a map for the next three to eighteen months. This does not mean that a firm should only run aggregate plans once every three to eighteen months. As inputs into the aggregate plan change, managers should use the latest values of these inputs and rerun the aggregate plan. By using the latest inputs, the plan will avoid suboptimization based on old data and will produce a better solution. For instance, as new demand forecasts become available, aggregate plans should be reevaluated.4. Use aggregate planning as capacity utilization increases. Surprisingly, many companies do not create aggregate plans and instead rely solely on orders from their distributors or warehouses to determine their production schedules. These orders are driven either by actual demand or through inventory management algorithms. If a company has no trouble efficiently meeting demand this way, then one could claim the lack of aggregate planning may not significantly harm the company. However, when utilization becomes high and capacity is an issue, relying on orders to set the production schedule can lead to capacity problems. When utilization is high, the likelihood of producing for all the orders as they arrive is very low. Planning needs to be done to best utilize the capacity to meet the forecasted demand. Therefore, as capacity utilization increases, it becomes more important to perform aggregate planning.Difficulty: Moderate。

Chapter 131.Aggregate planning occurs over the medium or intermediate future of 3 to 18 months. True (Introduction, easy)2.Aggregate planning in manufacturing ties organizational strategic goals to a productionplan.True (Introduction, moderate)3.One of the four things needed for aggregate planning is a logical overall unit formeasuring sales and output.True (Introduction, moderate)4.Plans for new product development generally fall within the scope of aggregateplanning.False (The planning process, moderate)5.One question that operations managers must answer when generating an aggregate planis should prices or other factors be changed to influence demand.True (Aggregate planning strategies, easy)6.In aggregate planning, one of the adjustable elements of capacity is the extent ofsubcontracting.True (Aggregate planning strategies, easy)7.The use of part-time workers as an aggregate planning option may be less costly thanusing full-time workers, but may also reduce quality levels.True (Aggregate planning strategies, moderate)8.Advertising and promotion are methods of manipulating product or service supply inaggregate planning.False (Aggregate planning strategies, moderate)9.Charting and graphing techniques are easy to understand and use, but are not well-suited for generating optimal strategies.True (Methods for aggregate planning, moderate)10.The transportation method of linear programming is an optimizing approach toaggregate planning.True (Methods for aggregate planning, easy)11.Which of the following statements regarding Anheuser-Busch is false?a. Aggregate planning is a major part of its competitive edge.b. All four stages of beer production are integrated into the aggregate plan.c. High facility utilization complements its successful aggregate planning.d. Its aggregate planning focuses entirely on facilities, ignoring employee issues.e. Even with excellent aggregate planning, its plants need to have high utilization.d (Global company profile, easy)12.Which of the following is the term used for medium range capacity planning with atime horizon of three to eighteen months?a. material requirements planningb. short-range planningc. strategic planningd. aggregate planninge. none of the aboved (Introduction, easy)13.Aggregate planning is capacity planning fora. the long rangeb. the intermediate rangec. the short ranged. typically one to three monthse. typically one or more yearsb (Introduction, easy)14.Which of the following is not one of the four things needed for aggregate planning?a. a logical overall unit for measuring sales and outputb. a method for determining costs, such as hiring, firing, and inventory costs, associatedwith production schedulesc. a mathematical model that will minimize costs over the intermediate planning periodd. an aggregate demand forecast for an intermediate planning periode. All of these are needed for aggregate planning.c (Introduction, easy)15.Which of the following statements about aggregate planning is true?a. Advertising/promotion is a way of manipulating product or service supply.b. Work station loading and job assignments are examples of aggregate planning.c. Overtime/idle time is a way of manipulating product or service demand.d. Aggregate planning uses the adjustable part of capacity to meet productionrequirements.e. All of the above are true.d (The planning process, moderate)16.Dependence on an external source of supply is found in which of the followingaggregate planning strategies?a. varying production rates through overtime or idle timeb. subcontractingc. using part-time workersd. back ordering during high demand periodse. hiring and laying offb (Aggregate planning strategies, moderate)17.Which of these is among the demand options of aggregate planning?a. subcontractingb. back-ordering during high-demand periodsc. changing inventory levelsd. varying workforce sizee. All of the above are demand options.b (Aggregate planning strategies, moderate)18.Which of the following aggregate planning strategies might direct your client to acompetitor?a. using part-time workersb. subcontractingc. changing inventory leveld. varying production rates through overtime or idle timee. varying work force size by hiring or layoffsb (Aggregate planning strategies, moderate)19.Which of these aggregate planning strategies adjusts capacity to match demand?a. back orderingb. using part-time workersc. counterseasonal product mixingd. changing pricee. None of the above is a capacity option.b (Aggregate planning strategies, moderate)20.Which of the following aggregate planning strategies is known to lower employeemorale?a. yield managementb. varying production rates through overtime or idle timec. changing inventory levelsd. varying work force size by hiring or layoffse. back ordering during high demand periodsd (Aggregate planning strategies, difficult)21.Which of the following is not associated with manipulation of product or servicedemand?a. price cuts or discountsb. promotionc. subcontractingd. counterseasonal products or servicese. advertisingc (Aggregate planning strategies, moderate)22.Which of the following attempts to manipulate product or service demand?a. inventoriesb. part-time workersc. subcontractingd. overtime/idle timee. price cutse (Aggregate planning strategies, moderate)23.Which of the following aggregate planning strategies is a "demand option"?a. changing priceb. subcontractingc. varying production levelsd. changing inventory levelse. using part-time workersa (Aggregate planning strategies, moderate)24.Which choice best describes level scheduling?a. Daily production is variable from period to period.b. Subcontracting, hiring, and firing manipulate supply.c. Price points are calculated to match demand to capacity.d. Inventory goes up or down to buffer the difference between demand and production.e. Seasonal demand fluctuations are matched without hirings or layoffs.d (Aggregate planning strategies, easy)25.In level scheduling, what is kept uniform from month to month?a. product mixb. inventory levelsc. production/workforce levelsd. demand levelse. sub-contracting levelsc (Aggregate planning strategies, moderate)26.Which of the following is not consistent with a pure level strategy?a. varying the use of subcontractingb. variable work force levelsc. little or no use of inventory to meet demand requirementsd. varying production levels and/or work force to meet demand requirementse. All of the above are inconsistent with the pure level strategy.e (Aggregate planning strategies, moderate)27.What four things are needed to develop an aggregate plan?To develop an aggregate plan, you need a logical overall unit for measuring sales and output, a forecast of demand for reasonable intermediate planning period in aggregate planning terms, a method for determining the cost associated with an aggregate plan, and a model that combines forecasts and costs so that scheduling decisions can be made for the planning period. (Introduction, mode rate)28.List (a) the demand options for aggregate planning; and (b) the capacity (supply)options for aggregate planning.Demand options are: influencing demand (through price, promotion, advertising, selling), back ordering during high demand periods, and counter-seasonal product mixing. Capacity options are: changing inventory levels, varying work force size by hiring or layoffs, varying production rate through overtime or idle time, subcontracting, and using part-time workers. (Aggregate planning strategies, moderate)pare the chase versus level strategy options.The chase strategy sets production equal to forecasted demand, using varying work force levels, overtime, idle time, part-time employees, or subcontracting. Its main advantage is low inventory levels. The level strategy maintains a constant output rate, production rate, or work force level over the planning horizon. A stable work force generally leads to better quality, less turnover and absenteeism, and more employee commitment to corporate goals. (Aggregate planning strategies, moderate)30.What are the disadvantages common to the following two strategies: (1) varyinginventory levels and (2) back ordering during periods of high demand?Varying inventory levels and back ordering have this disadvantage in common: customers may go elsewhere. (Aggregate planning strategies, moderate)MODULE B: LINEAR PROGRAMMING31.Linear programming helps operations managers make decisions necessary to makeeffective use of resources such as machinery, labor, money, time, and raw materials. True (Introduction, easy)32.One requirement of a linear programming problem is that the objective function mustbe expressed as a linear equation.True (Introduction, easy)33.In linear programming, a statement such as "maximize contribution" becomes anobjective function when the problem is formulated.True (Formulating linear programming problems, moderate)34.The region that satisfies all of the constraints in graphical linear programming is calledthe region of optimality.False (Graphical solution to a linear programming problem, moderate)35.The region that satisfies the constraint 4X + 15Z ≥ 1000 includes the origin of thegraph.False (Graphical solution to a linear programming problem, easy)36.In sensitivity analysis, a zero shadow price (or dual value) for a resource ordinarilymeans that the resource has not been used up.True (Sensitivity analysis, difficult)37.Which of the following represents valid constraints in linear programming?a. 2X ≥ 7X*Yb. 2X * 7Y ≥ 500c. 2X + 7Y ≥ 100d. 2X2 + 7Y ≥ 50e. All of the above are valid linear programming constraints.c (Requirements of a linear programming problem, moderate)38.The corner point solution method requiresa. finding the value of the objective function at the originb. moving the iso-profit line to the highest level that still touches some part of the feasibleregionc. moving the iso-profit line to the lowest level that still touches some part of the feasibleregiond. finding the coordinates at each corner of the feasible solution spacee. none of the aboved (Graphical solution to a linear programming problem, moderate)39.The region which satisfies all of the constraints in graphical linear programming iscalled thea. optimal solution spaceb. feasible solution spacec. profit maximization spaced. region of optimalitye. region of non-negativityb (Graphical solution to a linear programming problem, moderate)40. A shadow price (or dual value) reflects which of the following in a maximizationproblem?a. the marginal gain in the objective realized by subtracting one unit of a resourceb. the market price that must be paid to obtain additional resourcesc. the increase in profit that would accompany one added unit of a scarce resourced. the reduction in cost that would accompany a one unit decrease in the resourcee. none of the abovec (Sensitivity analysis, moderate)41.What is linear programming?42.What are the requirements of all linear programming problems?Linear programming problems require (1) maximization or minimization of an objective function, (2) the presence of restrictions (constraints), (3) alternative courses of action to choose from, and (4) the objective and constraints expressed in linear equations and inequalities. (Requirements of a linear programming problem, easy)43.What is the feasible region in a linear programming problem?The feasible region is the set of all feasible combinations of decision variables. (Graphical solution to a linear programming problem, moderate)44.What is the usefulness of a shadow price (or dual value)?Shadow prices and dual values are found in sensitivity analysis of linear programming solutions. They indicate what changes would take place in a solution if input data were changed. For a constraint, the shadow price indicates how much the objective function would change if more (or less) of that constraint's resource w ere added. (Sensitivity analysis, moderate)45.What is sensitivity analysis?Sensitivity analysis projects how much a solution might change if there w ere changes in the variables or input data. (Sensitivity analysis, easy)MODULE D: WAITING-LINE MODELS46.The two characteristics of the waiting line itself are whether its length is limited orunlimited and the discipline of the people or items in it.True (Characteristics of a waiting-line system, easy)47. A waiting-line system has three parts: the size of the arrival population, the behavior ofarrivals, and the statistical distribution of arrivals.False (Characteristics of a waiting-line system, easy)48.In queuing problems, arrival rates are generally described by the normal probabilitydistribution.False (Characteristics of a waiting-line system, moderate)49.Balk and renege are elements of queue discipline.False (Characteristics of a waiting-line problem, easy)50. A hospital emergency room always follows a first-in, first-served queue discipline inthe interest of fairness.False (Characteristics of a waiting-line system, moderate)51.In queuing problems, the term “renege” refers to the fact that some customers leave thequeue before service is completed.True (Characteristics of a waiting-line system, moderate)52. A waiting-line system with one waiting line and three sequential processing stages is amulti-channel single-phase system.False (Characteristics of a waiting-line problem, easy)53. A bank office with five tellers, each with a separate line of customers, exhibits thecharacteristics of a multi-phase queuing system.False (Characteristics of a waiting-line system, moderate)54.Four of the most widely used waiting line models—M/M/1 or A, M/M/S or B, M/D/1or C, and Limited population or D—all share three characteristics: Poisson arrivals,FIFO discipline, and exponential service times.False (The variety of queuing models, moderate)55.Study of waiting-line models helps operations managers better understanda. service systems such as bank teller stationsb. maintenance activities that might repair broken machineryc. shop-floor control activitiesd. service systems such as amusement park ridese. all of the abovee (Introduction, easy)56.Which of the following is not a common queuing situation?a. grocery shoppers being served by checkout clerksb. commuters slowing or stopping at toll plazas to pay highway tollsc. machinery waiting to be repaired or maintainedd. parcel delivery truck following its computer-generated routee. patients in a health clinic waiting to see one of several doctorsd (Introduction, easy)57.In queuing problems, which of the following probability distributions is typically usedto describe the number of arrivals per unit of time?a. binomialb. normalc. Poissond. exponentiale. lognormalc (Characteristics of a waiting-line system, easy)58.The shopper who says to himself, “I’ve waited too long in this line. I don’t really needto buy this product today,” and leaves the store is an illustration of which element ofarrival behavior?a. random arrivalb. renegec. random departured. balke. none of the aboveb (Characteristics of a waiting-line system, moderate)59. A waiting line, or queuing, system has three parts, which area. distribution of arrival times, discipline while waiting, and distribution of service timesb. arrival rate, service rate, and utilization ratec. arrival discipline, queue discipline, and service sequencingd. arrival or inputs, queue discipline or the waiting line itself, and the service facilitye. sequencing policy, penalty for reneging, and expediting of arrivalsd (Characteristics of a waiting-line system, moderate)60.The source population is considered to be either ________ in its size.a. finite or infiniteb. fixed or variablec. known or unknownd. random or schedulede. small or largea (Characteristics of a waiting-line system, moderate)61.The potential restauran t customer who says to her husband, “The line looks too long; let'seat somewhere else,” is an illustration of which element of queue discipline?a. first-in, first-outb. balkc. reneged. random departuree. none of the aboveb (Characteristics of a waiting-line system, moderate)62.If the food service for the university operates a cafeteria with a single serving line, thatsystem behaves most like aa. single channel, single phase systemb. single channel, multi-phase systemc. multi-channel, single phase systemd. multi-channel, multi-phase systeme. none of the aboveb (Characteristics of a waiting-line system, moderate)63.The sign at the bank that reads “Wait here for the first available teller” suggests the useof a _____ waiting line system.a. single phaseb. multi-phasec. single channeld. multi-channele. multiple lined (Characteristics of a waiting-line system, moderate)64. A small hair styling salon has several operators. While customers do not haveappointments, each is waiting to be served by a specific operator. This scenario provides an example of aa. multiple-channel, multi-phase, limited queue lengthb. single-channel, multi-phase, limited queue lengthc. multi-channel, limited queue lengthd. multiple single-channel systems, limited queue lengthe. none of the aboved (Characteristics of a waiting-line system, moderate)65. A large discount store and supermarket has a hair styling salon on its premises. The salonhas several operators. Salon customers can shop in other parts of the store until their name is called for salon service, at which time the customer will be served by the next available stylist. This scenario provides an example of aa. multiple-channel, multi-phase, unlimited queue lengthb. single-channel, multi-phase, limited queue lengthc. multi-channel, unlimited queue lengthd. multiple single-channel systems, limited queue lengthe. none of the abovec (Characteristics of a waiting-line system, moderate)66. A university has only one technician in the repair station to care for the computers in thestudent labs. This system is most likelya. a single channel, limited queue systemb. a single channel, limited population systemc. a multi-channel, limited queue systemd. a multi-channel, limited population systeme. none of the aboveb (Characteristics of a waiting-line system, moderate)67.“Women and children first!” declares the captain of a sinking ship. His directive employswhich of the following queue disciplines in disembarking passengers?a. priorityb. randomc. FIFO or FIFSd. LIFO or LIFSe. none of the abovea (Characteristics of a waiting-line system, moderate)68.Which of the following is a measure of queue performance?a. utilization factorb. average queue lengthc. probability of a specific number of customers in the systemd. average waiting time in the linee. all of the abovee (Characteristics of a waiting-line system, moderate)69.In a repetitive focus factory, the number of channels available for the processing of acertain part would likely refer toa. the number of successive operations that have to be performed on that partb. the number of machines doing the same necessary operationsc. the number of parts waiting to be processedd. all of the above depending on the layoute. none of the aboveb (Characteristics of a waiting-line system, moderate)70.Which one of the following is not a characteristic of a Model A or M/M/1 system?a. exponential service time patternb. single number of channelsc. single number of phasesd. Poisson arrival rate patterne. limited population sizee (The variety of queuing models, moderate)71.Which one of the following is not a characteristic of a Model B or M/M/S system?a. unlimited population sizeb. single channelc. single queued. single phasee. Poisson arrival rate patternb (The variety of queuing models, moderate)72.Which one of the following is not a characteristic of a Model C or M/D/1 system?a. single channelb. single phasec. Poisson arrival rate patternd. exponential service time patterne. unlimited population sized (The variety of queuing models, moderate)73.Customers take a number as they join the waiting line of the customer service counterat a discount store. There are two customer service agents. Provide the most likelycharacteristics of this system.a. name of modelb. number of channelsc. number of phasesd. arrival rate distributione. service time distributionf. population sizeg. queue disciplineMulti-channel system (M/M/S); two; single; Poisson; exponential; unlimited; andFIFO. (Characteristics of a waiting-line system, moderate)74.Students arrive randomly at the help desk of a computer lab. There is only one serviceagent, and the service time varies from one student to the other. Provide the most likelycharacteristics for this system.a. name of modelb. number of channelsc. number of phasesd. arrival rate distributione. service time distributionf. population sizeg. queue disciplineSingle channel system (M/M/1); single; single; Poisson; exponential; unlimited; and FIFO. (Characteristics of a waiting-line system, moderate)75.What are L s and L q, as used in waiting line terminology? Which is larger, L s or L q?Explain.L s is the average number of units in the system. L q is the average number of units in the waiting line. L s includes the average number of units in line as w ell as the average number of units being served. Consequently, L s is larger than L q by the average number of units actually being serviced. (Characteristics of a waiting-line system, moderate)76.What are the assumptions underlying the M/M/1 waiting line model? Which of thesealso hold for the M/D/1 model?The assumptions underlying the standard waiting line or queuing model are:1.Arrivals are served on a “first come,first served” (FCFS, or FIFO) basis; andevery arrival waits to be served regardless of the length of the line or queue.2.All arrivals are independent of preceding arrivals, and the average number ofarrivals per unit time (arrival rate) does not change over time.3.Arrival rates are described by a Poisson probability distribution, and arrivalscome from an infinite or very large source.4.Service times vary from one customer to another and are independent of oneanother, but their average rate is known.5.Service times are described by a negative exponential probability distribution.6.The effective service rate is faster than the arrival rate.Assumptions 4 and 5 do not apply to M/D/1.(The variety of queuing models, moderate)Chapter 1777.Maintenance includes all activities involved in keeping a system's equipment inworking order.True (The strategic importance of maintenance and reliability, easy)78.Adding an additional part to a component or product ordinarily reduces reliability byintroducing an additional source of failure.True (Reliability, moderate)79.Preventive maintenance implies that we can determine when a system needs service orwill need repair.True (Maintenance, moderate)80.Recording the maintenance history of processes, machines, or equipment is importantfor preventive maintenance, but largely irrelevant for breakdown maintenance.False (Maintenance, easy)81.The "full cost view of maintenance" results in more firms choosing a policy ofbreakdown maintenance, when compared to the "traditional view of maintenance." False (Maintenance, easy)82.The objective of maintenance is toa. ensure that breakdowns do not affect the quality of the productsb. ensure that no breakdowns will ever occurc. ensure that preventive maintenance costs are kept as low as possibled. maintain the capability of the system while controlling costse. ensure that maintenance employees are fully utilizedd (The strategic importance of maintenance and reliability, moderate)83.The probability that a product will function properly for a specified time under statedconditions isa. functionalityb. maintenancec. durabilityd. reliabilitye. fitness for used (The strategic importance of maintenance and reliability, moderate)84.Infant mortality refers to which one of the following examples?a. high frequency on the left side of the MTBF distributionb. failure of items used in the nursery ward of a hospitalc. failure of products with a very short life cycled. market failure of brand new productse. high failure rate often encountered in the very early stages of the lifetime of a producte (Maintenance, moderate)85.Which of the following costs tend to be ignored in determining the optimalmaintenance policy?a. expected breakdown costsb. preventive maintenance costsc. the costs associated with various levels of commitment to maintenanced. cost of low moralee. all of the aboved (Maintenance, moderate)86.List the two reliability tactics and the two maintenance tactics.Reliability tactics are improving individual components and providing redundancy. Maintenance tactics are implementing or improving preventive maintenance and increasing repair capabilities or speed. (The strategic importance of maintenance and reliability, moderate)87.Define reliability.Reliability is the probability that a machine part or product will function properly for a specified time under stated conditions. (The strategic importance of maintenance and reliability, moderate)88.Define maintenance.Maintenance is all activities involved in keeping a system's equipment in working order. (The strategic importance of maintenance and reliability, moderate)89.Explain carefully how redundancy improves product reliability.A redundant part or component is connected in parallel with the primary part or component. "In parallel" means that either the original part or its backup needs to work, not that both must work at the same time. Redundancy increases reliability by providing an additional path (through the redundant part) to provide system reliability. (Reliability, moderate)90.What is FR(N)? How is it calculated? How are FR(N) and MTBF related?FR(N) is the product failure number; it is the ratio of failed units to total operating hours. MT BF is the reciprocal ofFR(N). (Reliability, moderate)。