| dc.description.abstract | Natural disasters, such as earthquakes, volcanic eruption, mudflows and landslides, have significant devastating effects in terms of human injuries and property damages. The 1999 Chi-chi earthquake not only indicated the low efficiency of the government for dealing with the rescue operations but also revealed the importance of the emergency repair. In the past, the emergency repair was usually planned by decision makers according to their own experiences, lacking of systematic analyses. The resultant operation could possibly be a feasible yet inferior. Recent research has developed a model that finds the optimal work team routes for emergency road repairs to improve scheduling efficiently. However, it is difficult to optimally solve the problem within the shortest possible period of time. Therefore, we first develop a solution algorithm for this problem. Furthermore, a major disaster leads to subsequent “secondary” or “tertiary disasters” in practice, which delays the repair time or generates new damaged points. These large-scale perturbation problems will disrupt the original work teams’ repair schedule and will affect the follow-up resource assignment. In addition to the large-scale demand-side perturbation, the large-scale supply-side perturbation also affects the original schedule. For example, new work teams could be later supported by government, military or civil agencies, for more effective emergency repair. Therefore, we develop a model and solution algorithms for the highway emergency repair problem under large-scale supply-demand perturbations.
This dissertation consists of three essays. In the first essay, an ant colony system algorithm is employed, along with the threshold accepting technique, to develop an ACS-based hybrid algorithm capable of efficiently solving an emergency roadway repair time-space network flow problem. To test how well the algorithm may be applied to actual operations, a case study is carried out using data from the Chi-Chi earthquake in Taiwan. In the second essay, we develop a model and solution algorithms for the highway emergency repair problem under large-scale supply-demand perturbations. We employ the time-space network flow technique to develop a model that can help the authority decide on the best adjustment of highway emergency repair schedule. We use the C computer language, coupled with the CPLEX mathematical programming solver, to develop a heuristic algorithm for efficiently solving this problem. To evaluate the solution algorithms, we perform a case study. The results are good, showing that the model and heuristic algorithm could be useful. In the third essay, based on the problem’s characteristics, and ant colony system algorithm, we further develop three global search algorithms, coupled with the techniques of the threshold accepting algorithm and efficiently solve the problem. To evaluate the solution algorithms, we perform a case study on a scale similar to that of Chi-chi earthquake. The results are good, showing that the model and the algorithms may be useful in practice.
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