This research addresses analyzing and responding to uncertainty in projects with stochastic task durations. First we examine the effect of contractor flexibility (or agility) on project completion times. We find that this impact can be significant depending on the size and the structure of the project network.
Next we study a stochastic time-cost trade-off problem with penalties for exceeding a project deadline. In considering this problem, we take a contingency approach to decision making where crashing decisions are made dynamically throughout project execution. For serial projects we develop a dynamic programming algorithm as well as a variety of heuristic methods. Extending and modifying these methods for general projects allows us to deal with more complex network structures. Specifically, we propose hybrid dynamic programming/linear programming algorithms and simulation-based algorithms. We perform computational studies to assess the performance of each method and to compare the contingency approach with a static approach (where all crashing decisions are made before the project start time).
Finally, we study the case with penalties, incentives, and overhead costs. We find that when the project cost function is not convex, the dynamic programming solution may become non-monotonic, which requires further modification of the methods. We show that the performance of our algorithms does not deteriorate with inclusion of additional parameters. In fact, the gaps between the case with perfect information and the methods presented herein seem to be smaller than in the penalty only case.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-05122008-105456 |
| Date | 30 June 2008 |
| Creators | Glowacka, Karolina J. |
| Contributors | G.G. Hegde, Richard E. Wendell, Prakash Mirchandani, Jennifer Shang, Timothy Lowe |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-05122008-105456/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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