A Hybrid of Ant Colony Optimization Algorithm and Simulated Annealing for Classification Rules

Ant colony optimization (ACO) is a metaheuristic approach inspired from the behaviour of natural ants and can be used to solve a variety of combinatorial optimization problems. Classification rule induction is one of the problems solved by the Ant-miner algorithm, a variant of ACO, which was initiated by Parpinelli in 2001. Previous studies have shown that ACO is a promising machine learning technique to generate classification rules. However, the Ant-miner is less class focused since the rule’s class is assigned after the rule was constructed. There is also the case where the Ant-miner cannot find any optimal solution for some data sets. Thus, this thesis proposed two variants of hybrid ACO with simulated annealing (SA) algorithm for solving problem of classification rule induction. In the first proposed algorithm, SA is used to optimize the rule's discovery activity by an ant. Benchmark data sets from various fields were used to test the proposed algorithms. Experimental results obtained from this proposed algorithm are comparable to the results of the Ant-miner and other well-known rule induction algorithms in terms of rule accuracy, but are better in terms of rule simplicity. The second proposed algorithm uses SA to optimize the terms selection while constructing a rule. The algorithm fixes the class before rule's construction. Since the algorithm fixed the class before each rule's construction, a much simpler heuristic and fitness function is proposed. Experimental results obtained from the proposed algorithm are much higher than other compared algorithms, in terms of predictive accuracy. The successful work on hybridization of ACO and SA algorithms has led to the improved learning ability of ACO for classification. Thus, a higher predictive power classification model for various fields could be generated

New bounds for ternary covering arrays using a parallel simulated annealing

A covering array (CA) is a combinatorial structure specified as a matrix of N rows and k columns over an alphabet on v symbols such that for each set of t columns every t-tuple of symbols is covered at least once. Given the values of t, k, and v, the optimal covering array construction problem (CAC) consists in constructing a CA (N; t, k, v) with the minimum possible value of N. There are several reported methods to attend the CAC problem, among them are direct methods, recursive methods, greedy methods, and metaheuristics methods. In this paper, There are three parallel approaches for simulated annealing: the independent, semi-independent, and cooperative searches are applied to the CAC problem. The empirical evidence supported by statistical analysis indicates that cooperative approach offers the best execution times and the same bounds as the independent and semi-independent approaches. Extensive experimentation was carried out, using 182 well-known benchmark instances of ternary covering arrays, for assessing its performance with respect to the best-known bounds reported previously. The results show that cooperative approach attains 134 new bounds and equals the solutions for other 29 instances. © 2012 Himer Avila-George et al.The authors thankfully acknowledge the computer resources and assistance provided by Spanish Supercomputing Network (TIRANT-UV). This research work was partially funded by the following projects: CONACyT 58554; Calculo de Covering Arrays; 51623-Fondo Mixto CONACyT; Gobierno del Estado de Tamaulipas.Avila-George, H.; Torres-Jimenez, J.; Hernández García, V. (2012). New bounds for ternary covering arrays using a parallel simulated annealing. Mathematical Problems in Engineering. 2012:1-19. doi:10.1155/2012/897027S119201

Parameters estimation of induction machine single-cage and double-cage model using Hybrid Simulated Annealing–Evaporation Rate Water Cycle algorithm

This paper presents the usage of the hybrid simulated annealing—evaporation rate water cycle algorithm (SA-ERWCA) for induction machine equivalent circuit parameter estimation. The proposed algorithm is applied to nameplate data, measured data found in the literature, and data measured experimentally on a laboratory three-phase induction machine operating as an induction motor and as an induction generator. Furthermore, the proposed method is applied to both single-cage and double-cage equivalent circuit models. The accuracy and applicability of the proposed SA-ERWCA are intensively investigated, comparing the machine output characteristics determined by using SA-ERWCA parameters with corresponding characteristics obtained by using parameters determined using known methods from the literature. Also, the comparison of the SA-ERWCA with classic ERWCA and other algorithms used in the literature for induction machine parameter estimation is presented. The obtained results show that the proposed algorithm is a very effective and accurate method for induction machine parameter estimation. Furthermore, it is shown that the SA-ERWCA has the best convergence characteristics compared to other algorithms for induction machine parameter estimation in the literature

Étude numérique de l’impact de la distribution de catalyseur sur les performances des filtres à particules catalytiques

RÉSUMÉ: Les moteurs essence à injection directe (EID) sont une technologie en vogue pour limiter les émissions de gaz à effet de serre, grâce à d’importantes économies de carburant comparé aux autres technologies d’essence. Cependant, d’autres polluants sont émis par les véhicules à combustion interne, comme les particules fines et les oxydes d’azote (NOX) par exemple. Pour les traiter, des filtres à particules (FAP) et des chambres catalytiques (CC) sont appliqués aux systèmes de traitement des gaz d’échappement par les manufacturiers. Ces deux dispositifs sont constitués de monolithes fait de canaux rectangulaires. Dans le cas du FAP, les murs des canaux sont composés d’une céramique poreuse qui filtre les aérosols. Dans le cas des CC, les canaux sont imperméables à l’écoulement des gaz d’échappement et recouverts de catalyseur dans lequel les espèces chimiques à traiter diffusent. Afin d’abaisser les coûts et le volume de ces deux systèmes, il est possible d’intégrer le catalyseur directement dans la céramique qui forme les canaux du FAP. On parle alors de filtre à particule catalytique (FAPC). Cependant, cette déposition altère de façon significative les caractéristiques géométriques du FAPC à l’échelle du mur poreux. De plus en plus d’études s’intéressent ainsi à évaluer l’impact du dépôt de catalyseur sur les performances du FAPC en fonction, par exemple, de la quantité introduite, de la différence entre une déposition dans le mur ou sur le mur, ou encore d’un recouvrement par zones le long de chaque canal.----------ABSTRACT: Particulate filters (PF) have been used very successfully during the past decade to reduce particulate matter from the exhaust gas of modern vehicles. They consist in honeycomb monoliths made out of rectangular channels in most cases. These channels are alternatively plugged at the inlet or the outlet in order to force the exhaust gases to go through the porous material composing its walls. Catalytic chambers (CC) are open monoliths coated with precious metal composed catalysts. By diffusing in the catalyst, noxious gases as carbon monoxide (CO), nitrogen oxides (NOX) and hydrocarbons (HC) are reduced or oxidized in armless components like CO2, H2O and N2