Project Evaluation And Selection Of Interconnected Projects

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As traffic increases and links become congested, people may suffer delays and long travel time for their daily trips. Planners may decide to improve this situation for people in the area. One of the options for improving the conditions of traveling in the congested area is link expansion. Link expansion projects in transportation networks are almost always interdependent. When capacity of one link in a network changes it affects the flow of other links, and may shift bottle necks elsewhere throughout the network. In other words with respect to this expansion in one link, flow in other links may increase or decrease due to interdependency among them. So finding a sequence for a set of improvement projects needs consideration of their…show more content…
(Wang and Schonfeld. 2005) Along the same lines, simulation-based genetic search can be time consuming but with the advent of new technology and higher speed Processors, this problem is becoming less significant. Existing Studies mainly focuses on selecting and scheduling of projects with the assumption of being independent. There are two approaches which are commonly used for solving project selection and sequencing. The first approach is integer programming (Weingartner 1966; Cochran et al. 1971; Clark et al. 1984; Johnson et al. 1985) and the second one is dynamic programming (Weingartner 1966; Nemhauser and Ullman 1969; Morin and Esogbue 1971; Erlenkotter 1973; Morin 1974). [2] The first defect of these approaches is the difficulty of capturing the interdependencies among projects, and the second one is the inefficiency or even the infeasibility of the results in the case of responding to larger problems. Martinelli (1993) proposed a heuristic method for selecting and scheduling interdependent waterway investment projects. The results of this method are based on an evaluation to compare various combinations of project implementation over a time period. This method begins by establishing an initial sequence based on an independent evaluation. Then the initial solution is adjusted by using a heuristic which performs a swap (or swaps) in the sequence. This is done by plotting system cost
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