An analysis of post-selection in automatic configuration

info:eu-repo/semantics/publishe

An Empirical Study of Off-line Configuration and On-line Adaptation in Operator Selection

Automating the process of finding good parameter settings is important in the design of high-performing algorithms. These automatic processes can generally be categorized into off-line and on-line methods. Off-line configuration consists in learning and selecting the best setting in a training phase, and usually fixes it while solving an instance. On-line adaptation methods on the contrary vary the parameter setting adaptively during each algorithm run. In this work, we provide an empirical study of both approaches on the operator selection problem, explore the possibility of varying parameter value by a non-adaptive distribution tuned off-line, and incorporate the off-line with on-line approaches. In particular, using an off-line tuned distribution to vary parameter values at runtime appears to be a promising idea for automatic configuration. © 2014 Springer International Publishing.SCOPUS: cp.kinfo:eu-repo/semantics/publishe

Adaptive operator search for the capacitated arc routine problem

Evolutionary Computation approaches for Combinatorial Optimization have been successfully proposed for a plethora of different NP-Hard Problems. This research area has achieved acknowledgeable results and obtained remarkable progresses, and it has ultimately established itself as one of the most studied in AI. Yet, predicting the approximation ability of Evolutionary Algorithms (EAs) on novel problem instances remains a difficult easy task. As a consequence, their application in a real-world optimization context is reduced, as EAs are often considered not reliable and mature enough to be adopted in an industrial scenario. This thesis proposes new approaches to endow such meta-heuristics with a mechanism that would allow them to extract information during the search and to adaptively use such information in order to modify their behaviour and ultimately improve their performances. We consider the case study of the Capacitated Arc Routing Problem (CARP), to demonstrate the effectiveness of adaptive search techniques in a complex problem deeply connected with real-world scenarios. In particular, the main contributions of this thesis are: 1. An investigation of the adoption of a Parameter Tuning mechanism to adaptively choose the crossover operator that is used during the search; 2. The study of a novel Adaptive Operator Selection technique based on the use of Fitness Landscape Analysis techniques and on Online Learning; 3. A novel approach based on Knowledge Incorporation focusing on the reuse of information learned from the execution of a meta-heuristic on past instances, that is later used to improve the performances on the newly encountered