114 research outputs found

    Novelty grammar swarms

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    Tese de mestrado, Engenharia Informática (Sistemas de Informação), Universidade de Lisboa, Faculdade de Ciências, 2015Particle Swarm Optimization (PSO) é um dos métodos de optimização populacionais mais conhecido. Normalmente é aplicado na otimização funções de fitness, que indicam o quão perto o algoritmo está de atingir o objectivo da pesquisa, fazendo com que esta se foque em áreas de fitness mais elevado. Em problemas com muitos ótimos locais, regularmente a pesquisa fica presa em locais com fitness elevado mas que não são o verdadeiro objetivo. Com vista a solucionar este problema em certos domínios, nesta tese é introduzido o Novelty-driven Particle Swarm Optimization (NdPSO). Este algoritmo é inspirado na pesquisa pela novidade (novelty search), um método relativamente recente que guia a pesquisa de forma a encontrar instâncias significativamente diferentes das anteriores. Desta forma, o NdPSO ignora por completo o objetivo perseguindo apenas a novidade, isto torna-o menos susceptivel a ser enganado em problemas com muitos optimos locais. Uma vez que o novelty search mostrou potencial a resolver tarefas no âmbito da programação genética, em particular na evolução gramatical, neste projeto o NdPSO é usado como uma extensão do método de Grammatical Swarm que é uma combinação do PSO com a programação genética. A implementação do NdPSO é testada em três domínios diferentes, representativos daqueles para o qual este algoritmo poderá ser mais vantajoso que os algoritmos guiados pelo objectivo. Isto é, domínios enganadores nos quais seja relativamente intuitivo descrever um comportamento. Em cada um dos domínios testados, o NdPSO supera o aloritmo standard do PSO, uma das suas variantes mais conhecidas (Barebones PSO) e a pesquisa aleatória, mostrando ser uma ferramenta promissora para resolver problemas enganadores. Uma vez que esta é a primeira aplicação da pesquisa por novidade fora do paradigma evolucionário, neste projecto é também efectuado um estudo comparativo do novo algoritmo com a forma mais comum de usar a pesquisa pela novidade (na forma de algoritmo evolucionário).Particle Swarm Optimization (PSO) is a well-known population-based optimization algorithm. Most often it is applied to optimize fitness functions that specify the goal of reaching a desired objective or behavior. As a result, search focuses on higher-fitness areas. In problems with many local optima, search often becomes stuck, and thus can fail to find the intended objective. To remedy this problem in certain kinds of domains, this thesis introduces Novelty-driven Particle Swarm Optimization (NdPSO). Taking motivation from the novelty search algorithm in evolutionary computation, in this method search is driven only towards finding instances significantly different from those found before. In this way, NdPSO completely ignores the objective in its pursuit of novelty, making it less susceptible to deception and local optima. Because novelty search has previously shown potential for solving tasks in Genetic Programming, particularly, in Grammatical Evolution, this paper implements NdPSO as an extension of the Grammatical Swarm method which in effect is a combination of PSO and Genetic Programming.The resulting NdPSO implementation was tested in three different domains representative of those in which it might provide advantage over objective-driven PSO, in particular, those which are deceptive and in which a meaningful high-level description of novel behavior is easy to derive. In each of the tested domains NdPSO outperforms both objective-based PSO and random-search, demonstrating its promise as a tool for solving deceptive problems. Since this is the first application of the search for novelty outside the evolutionary paradigm an empirical comparative study of the new algorithm to a standard novelty search Evolutionary Algorithm is performed

    Opposition-Based Barebones Particle Swarm for Constrained Nonlinear Optimization Problems

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    This paper presents a modified barebones particle swarm optimization (OBPSO) to solve constrained nonlinear optimization problems. The proposed approach OBPSO combines barebones particle swarm optimization (BPSO) and opposition-based learning (OBL) to improve the quality of solutions. A novel boundary search strategy is used to approach the boundary between the feasible and infeasible search region. Moreover, an adaptive penalty method is employed to handle constraints. To verify the performance of OBPSO, a set of well-known constrained benchmark functions is used in the experiments. Simulation results show that our approach achieves a promising performance

    A novel design approach for NB-IoT networks using hybrid teaching-learning optimization

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    In this paper, we present and address the problem of designing green LTE networks with Internet of Things (IoT) nodes. We consider the new NarrowBand-IoT (NB-IoT) wireless technology that will emerge in current and future access networks. The main objective is to reduce power consumption by responding to the instantaneous bit rate demand by the user and the IoT node. In this context, we apply emerging evolutionary algorithms to the above problem. More specifically, we apply the Teaching-Learning-Optimization (TLBO), the Jaya algorithm, and a hybrid algorithm. This hybrid algorithm named TLBO-Jaya uses concepts from both algorithms in an effective way. We compare and discuss the preliminary results of these algorithms

    New few parameters differential evolution algorithm with application to structural identification

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    Differential evolution algorithm (DEA) is a stochastic, population-based global optimization method. In this paper, we propose new schemes for both mutation and crossover operators in order to enhance the performances of the standard DEA. The advantage of these proposed operators is that they are "parameters-less", without a tuning phase of algorithm parameters that is often a disadvantage of DEA. Once the modified differential evolutions are presented, a large comparative analysis is performed with the aim to assess both correctness and efficiency of the proposed operators. Advantages of proposed DEA are used in an important task of modern structural engineering that is mechanical identification under external dynamic loads. This is because of the importance of using a "parameters-less" algorithm in identification problems whose characteristics typically vary strongly case by case, needing of a continuous set up of the algorithm proposed. This important advantage of proposed optimizers, in front of other identification algorithms, is used to develop a computer code suitable for the automatic identification of a simple supported beam subject to an impact load, that has been tested both using numerical simulations and real standard tests dynamic. The results point out that this algorithm is an interesting candidate for standard applications in structural identification problems. Keywords: Differential evolution, Parametric identification, Structural identification, Optimizatio

    Social norms and human normative psychology

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    Our primary aim in this paper is to sketch a cognitive evolutionary approach for developing explanations of social change that is anchored on the psychological mechanisms underlying normative cognition and the transmission of social norms. We throw the relevant features of this approach into relief by comparing it with the self-fulfilling social expectations account developed by Bicchieri and colleagues. After describing both accounts, we argue that the two approaches are largely compatible, but that the cognitive evolutionary approach is well- suited to encompass much of the social expectations view, whose focus on a narrow range of norms comes at the expense of the breadth the cognitive evolutionary approach can provide

    Particle Swarm Optimization

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    Particle swarm optimization (PSO) is a population based stochastic optimization technique influenced by the social behavior of bird flocking or fish schooling.PSO shares many similarities with evolutionary computation techniques such as Genetic Algorithms (GA). The system is initialized with a population of random solutions and searches for optima by updating generations. However, unlike GA, PSO has no evolution operators such as crossover and mutation. In PSO, the potential solutions, called particles, fly through the problem space by following the current optimum particles. This book represents the contributions of the top researchers in this field and will serve as a valuable tool for professionals in this interdisciplinary field

    An intelligent computational approach to the optimization of inventory policies for single company

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    This study develops and tests a computational approach for determining optimal inventory policies for single company. The computational approach generally comprises of two major components: a meta-heuristic optimizer and an event-driven inventory evaluation module. Meta-heuristic is a powerful search technique, under the intelligent computational paradigm. The approach is capable of determining optimal inventory policy under various demand patterns regardless their distribution for a variety of inventory items. Two prototypes of perishability are considered: (1) sudden deaths due to disasters and (2) outdating due to expirations. Since every theoretical model is specially designed for a certain type of inventory problem while the real world inventory problems are numerous, it is desirable for the newly proposed computational approach to cover as many inventory problems/models as possible. In a way, the proposed meta-heuristic based approach unifies many theoretical models into one and beyond. Experimental results showed that the proposed approach provides comparable results to the theoretical model when demand follows their assumption. For demands not well conformed to the assumption, the proposed approaches are able to handle it but the theoretical approaches do not. This makes the proposed computational approach advantageous in that it can handle various types of real world demand data without the need to derive new models. The main motivation for this work is to bridge the gap between theory and practice so as to deliver a user-friendly and flexible computational approach for rationalizing the inventory control system for single company

    Wireless Mesh Networks Based on MBPSO Algorithm to Improvement Throughput

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    Wireless Mesh Networks can be regarded as a type of communication technology in mesh topology in which wireless nodes interconnect with one another. Wireless Mesh Networks depending on the semi-static configuration in different paths among nodes such as PDR, E2E delay and throughput. This study summarized different types of previous heuristic algorithms in order to adapt with proper algorithm that could solve the issue. Therefore, the main objective of this study is to determine the proper methods, approaches or algorithms that should be adapted to improve the throughput. A Modified Binary Particle Swarm Optimization (MBPSO) approach was adapted to improvements the throughput. Finally, the finding shows that throughput increased by 5.79% from the previous study
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