Multi-Objective Optimization of Network Systems by Using ANT Algorithms

Abstract

At the design stage, the availability of a network system can be improved by redundancy allocation or, for a fixed network topology, by selecting highly available elements as nodes and connection arcs. Yet these design choices are constrained by the available budget and other physical and logistic requirements. This paper formulates the network design problem as a multiple-objective optimization aiming at maximizing the network availability and minimizing its associated cost. The potential of using Ant algorithms to identify Pareto-optimal network designs with respect to the defined objectives is explored. For each solution, the network availability objectives is computed by a combination of Monte Carlo simulation and Cellular Automata. The Pareto-optimal solutions can be used by the decision-makers to identify compromise solutions which best satisfy their risk profiles. A sample network is solved as a demonstration of the proposed approach.

Key Words:

• Ant algorithms
• availability
• cellular automata
• Monte Carlo simulation
• multi-objective optimization
• network systems

Additional information

Notes on contributors

Enrico Zio

Enrico Zio Professor of Nuclear Engineering at the Politecnico di Milano and Chairman of the PhD in Radiation Science and Technolog of the Politecnico di Milano. His research topics include analysis of the reliability, safety and security of complex systems under stationary and dynamic operation, particularly by Monte Carlo simulation methods and cellular automata; development of soft computing techniques (neural networks, fuzzy logic, genetic algorithms) for safety and reliability applications, system monitoring, fault diagnosis and optimal design. Professor Zio is member of the editorial board of the international scientific journals Reliability Engineering and System Safety and Journal of Risk and Reliability. He has served as Vice-Chairman of the European Safety and Reliability Association, ESRA (2000–2005) and as Editor-in-Chief of the International journal Risk, Decision and Policy (2003–2004). He is currently the Chairman of the Italian Chapter of the IEEE Reliability Society (2001). He has functioned as Scientific Chairman of two International Conferences and as Associate General Chairman of two others, all in the field of Safety and Reliability. He is co-author of one international book and of more than 90 papers on international journals and serves as referee of 10 international journals.

Valérie Zille

Valérie Zille PhD student at Electricité de France for the Université de Technologie de Troyes. She works with the modelling and the simulation of complex maintenance policies for multi-components systems. Before this publication, she wrote a first article within the framework of her master in systems dependability.