This papers describes a perl language program to create time-to-target solution value plots for measured CPU times that are assumed to fit a shifted exponential distribution. This is often the case in local search based heuristics for combinatorial optimization, such as simulated annealing, genetic algorithms, iterated local search, tabu search, WalkSAT, and GRASP. Such plots are very useful in...

A large number of combinatorial optimization problems can presently only be solved to proven optimality if they are of very moderate size. This fact motivates the interest in approximation algorithms and heuristics. The former class of algorithms are able to guarantee the quality of the produced (suboptimal) solutions within certain bounds, while heuristics usually only have empirical evidence ...

In order to satisfy qualifying exam requirements adhered to by the School of Informatics and Computing, I will provide an overview of global optimization techniques, specifically simulated annealing, genetic algorithms, and tabu seach.

We propose a Multi-Phase Hybrid Metaheuristics approach for solving the Exam Timetabling Problem (ETP). This approach includes a pre-processing phase, a construction phase and an enhancement phase. The pre-processing phase involves two stages: the propagation of ordering constraints and implicit constraints discovery stages. The construction phase uses a variant of the Tabu search with conflict...

In this paper we consider discrete-continuous scheduling problems defined in [7], where general results and methodology have been presented as well. These problems are characterized by the fact that each job simultaneously requires for its processing at a time discrete and continuous (i.e. continuouslydivisible) resources. We deal with a class of these problems where there are: one discrete res...

A new algorithm called Enhanced Continuous Tabu Search (ECTS) is proposed for the global optimization of multiminima functions. It results from an adaptation of combinatorial Tabu Search which aims to follow, as close as possible, Glover's basic approach. In order to cover a wide domain of possible solutions, our algorithm ®rst performs the diversi®cation: it locates the most promising areas, b...

In this paper, we study the unrelated parallel machine problem for minimizing the makespan, which is NP-hard. We used Simulated Annealing (SA) and Tabu Search (TS) with Neighborhood Search (NS) based on the structure of the problem. We also used a modified SA algorithm, which gives better results than the traditional SA and developed an effective heuristic for the problem: Squeaky Wheel Optimiz...

The General Yard Allocation Problem (GYAP) is a resource allocation problem faced by the Port of Singapore Authority. Here, space allocation for cargo is minimized for all incoming requests for space required in the yard within time intervals. The GYAP is NP-hard for which we propose several heuristic algorithms, including Tabu Search, Simulated Annealing, Genetic Algorithms and the recently em...

The graph partitioning problem consists of dividing the vertices of a graph into a set of balanced parts, such that the number of edges connecting vertices in different parts is minimised. Although different algorithms to solve this problem have been proposed in complex graphs, it is unknown how good the partitions are since the problem is, in general, NP-complete. In this paper we present a ne...

This paper defines a new utility importance of a state of a component in multi-state systems. This utility importance overcomes some drawbacks of a well-known importance measure suggested by William S. Griffith (J. Applied Probability, 1980). The relationship between this new utility importance and the Griffith importance is studied and their difference is illustrated with examples. The contrib...