this paper, we explore this problem, which we call the network testbed mapping problem. We describe the interesting challenges that characterize this problem, and explore its application to other spaces, such as distributed simulation. We present the design, implementation, and evaluation of a solver for this problem, which is currently in use on the Netbed network testbed. It builds on simulated annealing to find very good solutions in a few seconds for our historical workload, and scales gracefully on large well-connected synthetic topologies

this paper we present several combinatorial algorithms for reconstructing a DNA strand given a collection of overlapping fragments of the strand. A human chromosome, which is a DNA molecule of about 10

Abstract — In this paper, we show how genetic algorithms can be useful in enhancing the performance of clustering algorithms in mobile ad hoc networks. In particular, we optimize our recently proposed weighted clustering algorithm (WCA). The problem formulation along with the parameters are mapped to individual chromosomes as input to the genetic algorithmic technique. Encoding the individual chromosomes is an essential part of the mapping process; each chromosome contains information about the clusterheads and the members thereof, as obtained from the original WCA. The genetic algorithm then uses this information to obtain the best solution (chromosome) defined by the fitness function. The proposed technique is such that each clusterhead handles the maximum possible number of mobile nodes in its cluster in order to facilitate the optimal operation of the medium access control (MAC) protocol. Consequently, it results in the minimum number of clusters and hence clusterheads. Simulation results exhibit improved performance of the optimized WCA than the original WCA. Moreover, the loads among clusters are more evenly balanced by a factor of ten. Index Terms—ad hoc networks, clustering, genetic algorithms, performance optimization I.

We consider a panel of experts asked to assign probabilities to events, both logically simple and complex. The events evaluated by different experts are based on overlapping sets of variables but may otherwise be distinct. The union of all the judgments will likely be probabilistic incoherent. We address the problem of revising the probability estimates of the panel so as to produce a coherent set that best represents the group's expertise.

Human judgment is an essential source of Bayesian probabilities but is plagued by incoherence when complex or conditional events are involved. We consider a method for adjusting estimates of chance over Boolean events so as to render them probabilistically coherent. The method works by searching for a sparse distribution that approximates a target set of judgments. (We show that sparse distributions suce for this purpose.) The feasibility of our method was tested by randomly generating sets of coherent and incoherent estimates of chance over 30 to 50 variables.

this paper, we propose, describe and evaluate a new simulated annealing algorithm based on the idea of maintaining an evolving target acceptance probability during optimization. In this algorithm, acceptance probability is elected as a new control parameter: the temperature of each Metropolis chain is estimated on the basis of an acceptance schedule

We describe the use of a tabu search algorithm for generating near minimum dominating sets in graphs. We demonstrate the effectiveness of this algorithm by considering a previously studied class of graphs, the so-called "football pool" graphs, and improving many of the known upper bounds for this class. 1 Introduction This paper describes a method for finding near-minimum dominating sets in graphs using a tabu search algorithm. Tabu search is the name given to a relatively new class of neighbourhood search algorithms that often appear to outperform other heuristic approximation methods on combinatorial optimisation problems (see Glover and Laguna [6]). In Davies [4], an investigation into a wide variety of methods for finding minimum dominating sets was conducted. There it was concluded that the most promising method is to express the domination problem as a combinatorial optimization problem and use algorithms for integer linear programming, particularly those for the set covering pr...

This thesis investigates a number of probabilistic and exhaustive computational search techniques for the construction of a wide variety of combinatorial designs, and in particular, incidence structures. The emphasis is primarily from a computer science perspective, and focuses on the algorithmic development of the techniques, taking into account running time considerations and storage requirements. The search and enumeration techniques developed in this thesis have led to the discovery of a number of new results in the field of combinatorial design theory. Page ii Page iii Acknowledgments I would like to extend my sincere thanks to a number of people who have given me a great deal of assistance and support throughout the preparation of this thesis. Firstly, my supervisor Peter Gibbons. I am very grateful for the encouragement and guidance he has given to me. His remarkable enthusiasm and friendliness have helped to make this thesis a most enjoyable experience. My family, for their...

The camera placement problem concerns the placement of a fixed number of point-cameras on the integer lattice of d-tuples of integers in order to maximize their visibility. We survey some of the combinatorial optimization and algorithmic techniques which have been developed in order to study this and other similar problems in the context of lattices and more generally, in combinations of lattice systems and tilings. 1 Introduction Visibility and illumination problems are among the most appealing and intuitive research topics of combinatorial geometry. In many cases (though not all) their analysis requires nothing more than basic topics from geometry, number theory and graph theory and as such they are very well suited for a wide audience [2]. In recent years there has been particular emphasis on the algorithmic component of visibility problems in polygonal configurations; as such they have come to be studied under the area of "art gallery (watchman) problems" which in turn lies at the...

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