Tutorial 12 - Project Management (Extra) Student

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Unformatted text preview: eeks. (b) Formulate an LP problem to crash this project to 10 weeks. Crash: Reduce the total project time to below its normal completion time Crash Time: The new time (t) for the specified activity Crash Cost: The cost we have to pay for to get the new time (t) for the specified activity Step1: Construct the project network by using the AON network Step2: Calculate the “Time Reduced” and “Crash Cost per week” for each activity Activity A B C D E F G Immediate Predecessors A B C D,E Activity A B C D E F G Normal Time 3 2 1 7 6 2 4 Immediate Predecessors A B C D,E Normal Time 3 2 1 7 6 2 4 Crash Time 2 1 1 3 3 1 2 Normal Cost ($) 1000 2000 300 1300 850 4000 1500 Crash Cost ($) 1600 2700 300 1600 1000 5000 2000 Time Reduced (3-2)=1 1 0 4 3 1 2 Crash Cost per week ($) (1600-1000)/(3-2)=600 700 0 75 50 1000 250 Step3: Formulate an LP problem to crash this project to 10 weeks Objective: Use the minimum total crash cost to reduce the project to 10 weeks Decision: Which activities should we crash and How many weeks should we reduce for that activity? (a) Define the decision variables Let Xstart be the earliest start time for a Project Number of nodes Xi be the ES for the activity i (where i = A, B, C, D, E, F, G) (Including the dummy nodes) Xfinish be the earliest finish time for a project Yi be the amount of time reduced / crashed for the activity i (where i = A, B, C, D, E, F, G) (b) Define the objective function Minimize total crash cost, Z= ____YA + ____YB + ____YC + ____YD + ____YE + ____YF + ____YG (c) Define the constraints Nu...
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This document was uploaded on 04/05/2014.

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