Optimizing Methods

The methods to find an optimal solution to the constrained resource scheduljn problem fall into two categories: mathematical programming (linear programme for the most part) and enumeration. In the 1960s, the power of LP improved from being able to handle three resources and 15 activities to four resources and 55 activities. But even with this capacity, LP is usually not feasible for reasonably large projects where there may be a dozen resources and thousands of activities. (See 118] and |41 ] for more detail.)

In the late 1960s and early 1970s, limited enumeration techniques were applied to the constrained resource problem with more success. Tree search and branch and bound methods 150) were devised to handle up to five resources and perhaps 200 activities. Advances in LP techniques now allow LP to be used on large constrained resource scheduling problems.

More recent approaches have combined programming and enumeration methods. Patterson and Huber |42|, for example, employ an integer programming approach combined with a minimum bounding procedure to reduce the computation time for minimizing project duration. Similarly, Talbot |52] uses integer programming and implicit enumeration to formulate and solve problems where the completion time is a function of the resources allocated to the project.

One problem with even the newer combination of approaches is that the characteristics of problems that can be usefully addressed with these methods is still largely unknown. Why various methods will work on one problem and not on a similar problem is still being researched.

ractice cpnsylvania Electif

Pennsylvania Electric Company, headquartered in Johnstown, PA, operates generating facilities with a capacity of 6950 megawatts to serve 547,000 customers over an area of 17,600 square miles. The Generation Division Planning Group is responsible for planning all maintenance and capital projects. In the early 1980s, the group used a manual method of planning with hand-drawn charts. The planning process has now been computerized, which is faster, allows "what-if" analyses, and controls more than just the previously monitored critical path. In bringing the planning process in-house, the group also saved S 100,000 a year in service fees from an outside engineering firm who was planning their construction activities.

A special feature of the computerized system is its resource constraining module which establishes labor requirements across all jobs. In the pilot program to test the new software, $300,000 was saved when it was discovered that a job could be done with 40 percent fewer mechanics than normally used and still complete the job on time. In another application, It was found that a turbine disassembly and inspection could be added to the task list without delaying the project or exceeding the project budget.

After worker-hours are input to the program by activity, actual progress is monitored (see figure) and schedule and cost deviations are highlighted for management attention. This allows management to make adjustments to recover the schedule, slow the project down, or acquire more funds to get the

Source: A. I. Cantanese, "At Penelec. Project Management is a Way of Life," Project Management journal, December 1990.

Total Engineers-GDE 15 Eng. at 6 hrs/day; 7 Eng. at 7 hr/day

Worker-hours 4000

Total Engineers-GDE 15 Eng. at 6 hrs/day; 7 Eng. at 7 hr/day

Worker-hours 4000

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Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

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