생산운영관리 Ch. 5. Strategic Capacity Planning for Products and Services (전략적 생산용량 계획) Hansoo Kim (金翰秀) Dept. of Management Information Systems, YUST
이번주 까지 했어야 하는 일들… o 읽기: Chapter 17, and Chapter 5, 5 s o Play with MS-Project®
Ch. 17 중요 요점 o o o What is Project? What is Project Management? Project Planning, Scheduling, and Controlling Matrix Organization, WBS (Work-Breakdown-Structure) Network Diagram n n o o o AON, AOA Finding Critical Path o Forward Calculation/Backward Calculation Gantt Chart PERT/CPM Project Management Problem n n n o Is the project on schedule, ahead of schedule, or behind schedule? Is the project over or under cost budget? Are there enough resources available to finish the project on time? If the project must be finished in less than the scheduled amount of time, what is the way to accomplish this at least cost? Crashing
OM Overview Class Overview (Ch. 0) X Operations, Productivity, and Strategy (Ch. 1, 2) Project Management (Ch. 17) X Strategic Capacity Planning (Ch. 5, 5 S) Mgmt of Quality/ Six Sigma Quality (Ch. 9, 10) Queueing/ Simulation (Ch. 18) Supply Chain Management (Ch 11) Location Planning and Analysis (Ch. 8) Demand Mgmt Forecasting (Ch 3) X Aggregated Planning (Ch. 13) Inventory Management (Ch. 12) MRP & ERP (Ch 14) Process Selection/ Facility Layout; LP (Ch. 6, 6 S) JIT & Lean Mfg System (Ch. 15) Term Project
OM Expert가 되기 위해서…
학습목표 o 생산용량계획의 중요성을 설명할 수 있다 o 생산용량을 정의하고 측정하는 방법을 토의 한다 o 유효생산용량의 결정요소들을 기술한다 o 생산용량 대안 개발과 관련된 주요 고려사항 들을 토의한다 o 생산용량 대안을 평가하는 데 유용한 도구들 을 간단히 기술한다
Terms (용어) 영어 중국어 Bottleneck operation 瓶颈 作业 Expected monetary value(EMV)criterion 预 期币值标 准 Break-even point 盈亏平衡点 Expected value of perfect information(EVPI) 完全信息预 期价值 Capacity 运营 能力 Laplace Capacity cushion 运营 能力缓 冲 Maximax Cash flow 现 金流 Maximin Diseconomies of scale 规 模不经济 Minimax regret Economies of scale 规 模经济 Payoff table Outsource 外包 Regret (opportunity loss) Present value 现值 Risk 风险 Bounded rationality 有限理性 Sensitivity analysis 灵敏度分析 Suboptimization 局部最优 化 Certainty Decision tree 决策图标 Uncertainty 结 算表
Capacity(运营 能力, 생산용량) Planning o Capacity (생산용량): 한 생산 단위가 처리할 수 있는 최대 부하 the upper limit or ceiling on the load that an operating unit can handle. n Eg. # of bicycle assembled in an hr o 생산용량에 포함되는 요소들 n n n Equipment (설비) Space (공간) Employee skills (작업능력) Over-capacity? Under-capacity? o 생산용량계획 수립시 기본질문들… The basic questions in capacity handling are: n n n What kind of capacity is needed? (어떤 종류의 생산용량이 필요한가? ) How much is needed? (얼마나 필요한가? ) When is it needed? (언제 필요한가? )
생산용량 결정의 전략적 속성 1. 2. 3. 4. 5. 6. 7. 8. 미래에 발생할 수요를 충족하는 능력에 영향을 준다 생산용량 결정은 생산비용에 영향을 준다. 생산용량은 보통 초기 투자의 주요 구성요소이다. 생산용량 결정은 장기적 관점의 의사결정이다. 생산용량 결정은 경쟁력에 영향을 미친다. 생산용량 결정에 따라 관리의 용이성이 달라질수 있 다. 글로벌화로 인해 생산용량 결정이 더 중요해지고 복 잡해 졌다. 생산용량결정은 충분한 시간을 두고 결정해야할 중요 한 의사결정이다. Capacity Decisions are Strategic!!!
생산용량의 정의 o Design capacity (설계용량) n n 설계시 결정된 최대 산출물이나 서비스 용량 Maximum output rate or service capacity an operation, process, or facility is designed for o Effective capacity (유효생산용량) n n 설계용량에서 인적요인 또는 기타 이유로 인한 공제량을 뺀 용량 Design capacity minus allowances such as personal time, maintenance, and scrap o Actual output (실제산출률) n n 실제 산출률 – 유효생산용량을 초과할수 없음 Rate of output actually achieved--cannot exceed effective capacity.
Efficiency(효율) and Utilization(이용률) Efficiency = Utilization = Actual output Effective capacity Actual output Both measures expressed as percentages Design capacity Example 1 Design capacity = 50 trucks/day Effective capacity = 40 trucks/day Actual output = 36 units/day Key to improving capacity ~ |Efficiency – Utilization|
유효생산용량에 영향을 미치는 요인 Determinants of Effective Capacity o Facilities (시설) o o Policy(정책) Operational(운영) n n n o o Design (설계) Product or service mix (제품/서비스 믹스) n n o Design (설계) Location (위치) Layout (배치) Environment (환경) Quantity capabilities(양적 능력) Quality capabilities(품질 능력) n n n n Job content(직무 내용) Job design(직무 설계) Training and experience(훈련과경험) Motivation(동기유발) Compensation(보상) Learning rates(학습 속도) Absenteeism and labor turnover(결 근 및 퇴직률) n n Product/service (제품/서비스) Process (프로세스) Human factors (인적 요인) o o Scheduling(스케줄링) Materials management(자재 관 리) Quality assurance(품질 보증) Maintenance policies(보전 정 책) Equipment breakdowns(장비 고장) Supply chain(공급사슬) External factors (외적요인) n n Product standards(제품 표준) Safety regulations(안전 규제) Unions(노조) Pollution control standards(공 해 관리 기준)
생산용량계획의 주요 의사결정 Key Decisions of Capacity Planning 1. 필요생산용량 Amount of capacity needed • 여유생산용량 (Capacity cushion) = (100% - Utilization) 2. Timing of changes 3. Need to maintain balance 4. Extent of flexibility of facilities Capacity cushion – extra demand intended to offset uncertainty 수요의 불확실성을상쇄시키기 위한 추가적인 생산 용량
생산용량계획 절차: Steps for Capacity Planning 1. 미래 필요 생산용량 추정 (Estimate future capacity requirements) 2. 현재 생산용량 평가 (Evaluate existing capacity) 3. 대안 파악 (Identify alternatives) 4. 재무 분석 수행 (Conduct financial analysis) 5. 정성적 요인 평가 (Assess key qualitative issues) 6. 대안 선택 (Select one alternative) 7. 실행 (Implement alternative chosen) 8. 결과 모니터링 (Monitor results)
생산용량소요 예측 Forecasting Capacity Requirements o Long-term vs. short-term capacity needs n Long-term relates to overall level of capacity such as facility size, trends, and cycles n Short-term relates to variations from seasonal, random, and irregular fluctuations in demand Figure 5 -1 Common demand patterns
생산용량 계산 (Calculating Processing Requirements) 년간 용량이 2000시간/기계 라면, 우리는 5800시간을 확보하기 위해 2. 9대의 설 비가 필요하다 5, 800 (hours)/2, 000 (hours/mc) = 2. 90 machines
서비스용량계획: Planning Service Capacity Service o Need to be near customers (용량과 고객이 근접함) n Capacity and location are closely tied o Inability to store services (서비스 용량은 저장이 안됨) n Capacity must be matched with timing of demand o Degree of volatility(휘발성) of demand n Peak demand periods
생산용량, 자체생산이냐 구매냐? In-House or Outsourcing* 1. 가용생산 용량 Make or Buy? Available capacity 2. 전문성; Expertise 3. 품질; Quality considerations 4. 수요의 특성; Nature of demand Outsource(외주): 외부공급자로 부터 제품과 서비스를 공급받는 5. 원가; Cost 것 obtain a good or service from an 6. 위험; Risk external provider
생산용량 대안 개발 (Developing Capacity Alternatives) 1. 시스템을 유연하게 설계하라 Design flexibility into systems 2. 수명주기 단계를 감안하라 Take stage of life-cycle into account 3. 시스템 사고로 생산용량 변경에 접근하라 Take a “big picture” approach to capacity changes (not to be suboptimal) 4. 생산용량을 덩어리 (Chunk)로 다룰 준비를 하라 Prepare to deal with capacity “chunks” 5. 생산용량소요를 평준화 하도록 시도하라 Attempt to smooth out capacity requirements 6. 최적 운영수준을 파악하라. Identify the optimal operating level
병목공정 Bottleneck Operation sub optimization Figure 5. 2 Operation 1 20/hr. Operation 2 10/hr. Bottleneck operation: An operation in a sequence of operations whose capacity is lower than that of the other operations 일련의 공정들 중에서 생산용량이 가장 작은 공정 Operation 3 15/hr. Maximum output rate limited by bottleneck 10/hr.
규모의 경제 Economies of Scale o Economies of scale n 규모의 경제: 산출률이 최적 수준 이하면, 산출률을 늘리 면 단위 당 평균 원가는 내 려간다. o Diseconomies of scale n 규모의 비경제: 산출률이 최적수준이상이면 산출률을 늘리면 단위 당 평균 원가는 올라간다
Economies of Scale Minimum cost & optimal operating rate are functions of size of production unit. Figure 5. 5
대안 평가 Evaluating Alternatives o 비용-조업도 분석 (Cost-volume analysis) n 손익분기점 Break-even point o 재무분석 (Financial analysis) n 현금 흐름 (Cash flow) n 현재 가치 (Present value) o 의사결정 이론 (Decision theory) o 대기행렬 분석 (Waiting-line analysis)
비용-조업도 관계 Cost-Volume Relationships FC = Fixed cost VC = Total variable cost v = Variable cost per unit TC = Total cost TR = Total revenue R = Revenue per unit Q = Quantity or volume of output QBEP = Break-even quantity P = Profit TC=FC+VC VC=Q*v
손익분기점 분석 Break-Even Analysis
Example 3 o Adding a new line of pies, which will require leasing new equipment for a monthly payment of $6, 000. Variable costs would be $2. 00 per pie, and pies would retail for $7. 00 each. 1. 2. 3. 4. SOLUTION How many pies must be sold in order to break even? What would the profit (loss) be if 1, 000 pies are made and sold in a month? How many pies must be sold to realize a profit of $4, 000? If 2, 000 can be sold, and a profit target is $5, 000, what price should be charged per pie?
복수손익분기점 문제: Break-Even Problem with Step Fixed Costs EXAMPLE 4
의사결정 이론 Decision Theory Ch. 5 S
Decision Theory represents a general approach to decision making which is suitable for a wide range of operations management decisions, including: Capacity planning Product and service design Location planning Equipment selection
Decision Process 1. 2. 3. 4. 5. 6. 7. Identify the problem Specify objectives and criteria for a solution Develop suitable alternatives Analyze and compare alternatives Select the best alternative Implement the solution Monitor to see that the desired result is achieved
Decision Environments o Certainty - Environment in which relevant parameters have known values o Risk - Environment in which certain future events have probable outcomes o Uncertainty - Environment in which it is impossible to assess the likelihood of various future events 1. Profit per unit is $5. You have an order for 200 units. How much profit will you make? (This is an example of certainty since unit profits and total demand are known. ) 2. Profit is $5 per unit. Based on previous experience, there is a 50 percent chance of an order for 100 units and a 50 percent chance of an order for 200 units. What is expected profit? (This is an example of risk since demand outcomes are probabilistic. ) 3. Profit is $5 per unit. The probabilities of potential demands are unknown. (This is an example of uncertainty. )
Decision Making under Certainty (확 정성하의 의사결정) Payoff table Solution: Choose the alternative with the highest payoff If demand is low, take “small facility” alternative If demand is moderate, take “Medium facility” alternative If demand is high, take “Large facility” alternative
Decision Making under Uncertainty (불확정성하의 의사결정) Maximin - Choose the alternative with the best of the worst possible payoffs Maximax - Choose the alternative with the best possible payoff Laplace - Choose the alternative with the best average payoff of any of the alternatives Minimax Regret - Choose the alternative that has the least of the worst regrets
Decision Making under Uncertainty (불확정성하의 의사결정) (a) Maximin (b) Maximax (c) Laplace For the Laplace criterion, first find the row totals, and then divide each of those amounts by the number of states of nature (three in this case). (d) Minimax Regret (Opportunity Losses)
Decision Making Under Risk (위험(불확실성)하의 의사결정) o Risk: The probability of occurrence for each state of nature is known o Risk lies between the extremes of uncertainty and certainty o Expected monetary value (EMV) criterion: n The best expected value among alternatives n Determine the expected payoff of each alternative, and choose the alternative with the best expected payoff When demand probabilities are distributed as follows low =. 30, moderate =. 50, and high =. 20.
의사결정 나무 (Decision Tree) o Decision tree: a Schematic representation of the available alternatives and their possible consequences.
Example o A manager must decide on the size of a video arcade to construct. The manager has narrowed the choices to two: large or small. Information has been collected on payoffs, and a decision tree has been constructed. Analyze the decision tree and determine which initial alternative (build small or build large) should be chosen in order to maximize expected monetary value.
(평균완전정보비용) Expected Value of Perfect Information (EVPI) Expected value of perfect information: the difference between the expected payoff under certainty and the expected payoff under risk Expected value of Expected payoff perfect information = under certainty In the previous example, - Expected payoff under risk
민감도 분석 Sensitivity Analysis o Sensitivity Analysis: Determining the range of probability for which an alternative has the best expected payoff o Useful for decision makers to have some indication of how sensitive the choice of an alternative is to changes in one or more of these values Example 5 s-8
요약 o Capacity Planning o Decision Theory
HW# o Review all Solved Problems on Ch. 5, 5 s n Do not need to hand-in (좋지? !)
To be OM Expert !!! Capacity Planning & Decision Theory
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