We present a hybrid search technique based on metaheuristics for approximately solving the vehicle routing problem with time windows (VRPTW). The approach is two phased; a global customer clustering phase based on genetic algorithms (GAs) and a post-optimization local search technique based on tabu search (TS). We also devise a new crossover operator for the VRPTW and compare its performance wi...

KULKARNI, GIRISH. A Tabu Search Algorithm for the Steiner Tree Problem. (Under the direction of Professor Yahya Fathi.) The Steiner Tree problem in graphs is an NP-hard problem having applications in many areas including telecommunication, distribution and transportation systems. We survey, briefly, a few exact methods and a few heuristic approaches that have been proposed for solving this prob...

A number of non-exhaustive search algorithms are presented. The methods are a c̀lassical’ genetic algorithm, a tabu search, an evolutionary strategy and stochastically repeated nearest and steepest-ascent hill-climbing algorithms. They are then used to determine optimum and good polarities for Reed± Muller canonical expansions of Boolean functions, and comparisons are drawn between the relative ...

The setting could have come from a Hollywood science fiction movie. A dozen figures, a handful in uniforms of the U.S. Strategic Air Command (SAC) and a slightly larger contingent variously in business suits and in shirtsleeves, were gathered around a large mainframe computer whose blinking lights signaled a run in progress. The computer run — on an early70s behemoth that represented the state-...

ion and decomposition (through explicit and attributive memory) Timing Recency of events Frequency of events Differentiation between short term and long term Quality and impact Relative attractiveness of alternative choices Magnitude of changes in structure or constraining Relationships Context Regional interdependence Structural interdependence Sequential interdependence Responsive Exploration...

We describe the main features of tabu search, emphasizing a perspective for guiding a user to understand basic implementation principles for solving combinatorial or nonlinear problems. We also identify recent developments and extensions that have contributed to increasing the efficiency of the method. One of the useful aspects of tabu search is the ability to adapt a rudimentary prototype impl...

We study and compare synchronous parallelization strategies for tabu search. We identify the most promising parallelization approaches, and evaluate the impact on performance and solution quality of some important algorithmic design parameters: length of the synchronization steps, number of processors, handling of exchanged information, etc. Parallelization approaches are implemented and compar...

Multicommodity distribution problem is one of the most interesting and useful models in mathematical programming due to its major role in distribution networks. The purpose of this paper is to describe and solve a special class of multicommodity distribution problems in which shipment of a commodity from a plant to a customer would go through different distribution centers. The problem is t...

This paper considers a time dependent(the travel time is not constant throughout the day) pollution routing problem (TDPRP), which aids the decision makers in minimizing travel time, toll cost and emitted pollution cost.  In complexity of urban areas most of the time one point is accessible from another with more than one edge. In contrast to previous TDPRP models, which are designed with only ...

The mathematical modeling of fracture networks is critical for the exploration and development of natural resources. Fractures can help the production of petroleum, water, and geothermal energy. They also greatly influence the drainage and production of methane gas from coal beds. Orientation and spatial distribution of fractures in rocks are important factors in controlling fluid flow. The obj...