Resource AllocationSome DefinitionsNormal and CrashingNo Free Lunch: Crashing Creates a Ripple EffectCase: Architectural Associates, Inc.Case: Architectural Associates, Inc. (cont’d)Case: Architectural Associates, Inc. (concluded)When Trying to Crash a Project . . .Compute Cost per Day of Crashing a ProjectAn Example (Table 9-1)Example (cont’d): Cost per Day to Crash (Table 9-2)A CPM Example, Figure 9-1CPM Cost-Duration, Figure 9-2Another Approach to Expediting: Fast-tracking/ConcurrencyFast-tracking/Concurrency (cont’d)“Cost, Schedule, or Performance: Pick Any Two . . .”Resource LoadingResource Usage Calendar, Figure 9-3AOA Network, Figure 9-4Modified PERT/CPM AOA, Figure 9-5Resource LevelingLoad Diagrams, Figure 9-6Network Before and After Resource Loading, Figure 9-7Load Diagrams, Figure 9-8Resource Loading Chart, Figure 9-9Constrained Resource SchedulingMSP Gantt with Resources, Figure 9-10MSP Load Diagram, Showing Resource Conflict, Figure 9-11MSP Load Diagram, Leveled, Figure 9-12Network for Resource Load Simulation, Figure 9-13Load Chart, Figure 9-14Task a Decomposed, Figure 9-15Hierarchy of Gantt Charts, Figure 9-16Sources and Uses of Resources, Figure 9-17Project Life Cycles, Figure 9-18Flow Diagram for SPAR-1, Figure 9-19Goldratt’s Critical ChainSome Systemic Causes of Late ProjectsSome Systemic Causes of Late Projects (cont’d)Some Systemic Causes of Late Projects (concluded)9-1Resource AllocationSome definitionsResource allocation, loading, levelingExpediting and crashing projectsGoldratt’s “Critical Chain”9-2Some DefinitionsResource allocation permits efficient use of physical assetsWithin a project, or across multiple projectsDrives both the identification of resources, and timing of their applicationThere are generally two conditions:“Normal”“Crashed”9-3Normal and CrashingNormal: Most likely task duration, like “m” in Chapter 8Crash: Expedite an activity, by applying additional resourcesSpecialized or additional equipmentMore people (e.g., borrowed staff, temps)More hours (e.g., overtime, weekends)9-4No Free Lunch: Crashing Creates a Ripple EffectCrashing buys time, but nothing comes freePotential cost areasAdditional equipment/materialExtra laborNegative effects on other projectsReduced morale, from excessive hours/shiftsLower quality, from the pressure of time, inexperienced and tired staff“If you want it bad, you’ll get it bad . . .”9-5Case: Architectural Associates, Inc.Projects uniformly run late, thus over budgetIs that the problem, or just the symptom?9-6Case: Architectural Associates, Inc. (cont’d)PROBLEM: Deterministic task schedules cause workers to plan to meet schedule – nothing more, nothing lessParkinson’s Law: “Work expands to fill the time available.”RESULT: Issues arising early in each task can be worked around, but late-occurring issues can’t be absorbed in scheduleAnd most issues do arise late9-7Case: Architectural Associates, Inc. (concluded)The Solution:Use probabilistic time estimates (optimistic, pessimistic, most likely)Have staff schedule work for effectiveness and efficiency, not just to fill x-number of days9-8When Trying to Crash a Project . . .Two basic principles1. Generally, focus on the critical pathUsually not helpful to shorten non-critical activitiesException: When a scarce resource is needed elsewhere, e.g., in another project2. When shortening project duration, choose least expensive way to do it9-9Compute Cost per Day of Crashing a ProjectCompute cost/time slope for each expeditable activitySlope = crash cost – normal cost crash time – normal time9-10An Example (Table 9-1)Activity Predecessor Days(normal, crash)Cost(normal, crash)a - 3, 2 $40, 80b a 2, 1 20, 80c a 2, 2 20, 20d* a 4, 1 30, 120e** b 3, 1 10, 80* Partial crashing allowed** Partial crashing not allowed9-11Example (cont’d): Cost per Day to Crash (Table 9-2)Activity $ Saved/Daya 40b 60c -d 30e 70 (2 days)9-12A CPM Example, Figure 9-19-13CPM Cost-Duration, Figure 9-29-14Another Approach to Expediting: Fast-tracking/ConcurrencyDifferent terms for similar concept“Fast-tracking” (construction), “Concurrent engineering” (manufacturing)Both refer to overlapping project phasesE.g., design/build, or build/test9-15Fast-tracking/Concurrency (cont’d)Pros: Can shorten project durationCan reduce product development cyclesCan help meet clients’ demandsCons:Can increase cost through redesigns, excessive changes, rework, out-of-sequence installation, and more9-16“Cost, Schedule, or Performance: Pick Any Two . . .”Assuming fixed performance specifications, tradeoff areas must be in time or costTime-limited or resource-limitedIf all three dimensions are fixed, the system is “overdetermined”Normally, no tradeoffs are possibleBut, something has to give . . .9-17Resource LoadingResource loading: types and quantities of resources, spread by schedule across specific time periodsOne project, or manyIdentifies and reduces excess demands on a firm’s resources9-18Resource Usage Calendar, Figure 9-39-19AOA Network, Figure 9-49-20Modified PERT/CPM AOA, Figure 9-59-21Resource LevelingResource leveling minimizes period-by-period variations in resource loading, by shifting tasks within their slack allowancesAdvantagesLess day-to-day resource manipulation neededBetter morale, fewer HR problems/costsLeveling resources also levels costs, simplifies budgeting and funding9-22Load Diagrams, Figure 9-69-23Network Before and After Resource Loading, Figure 9-79-24Load Diagrams, Figure 9-89-25Resource Loading Chart, Figure 9-99-26Constrained Resource SchedulingTwo basic approachesHeuristicRule-based, rules of thumbPriority rules, tie-breakersOptimizationNot finding an answer that works, but the best answer9-27MSP Gantt with Resources, Figure 9-109-28MSP Load Diagram, Showing Resource Conflict, Figure 9-119-29MSP Load Diagram, Leveled, Figure 9-129-30Network for Resource Load Simulation, Figure 9-139-31Load Chart, Figure 9-149-32Task a Decomposed, Figure9-159-33Hierarchy of Gantt Charts, Figure 9-169-34Sources and Uses of Resources, Figure 9-179-35Project Life Cycles, Figure 9-189-36Flow Diagram for SPAR-1, Figure 9-199-37Goldratt’s Critical ChainThere are systemic problems that plague project schedule
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