2013
Autores
Pereira, I; Madureira, A; de Moura Oliveira, P;
Publicação
Intelligent Systems, Control and Automation: Science and Engineering
Abstract
This paper proposes a novel agent-based approach to Meta-Heuristics self-configuration. Meta-heuristics are algorithms with parameters which need to be set up as efficient as possible in order to unsure its performance. A learning module for self-parameterization of Meta-heuristics (MH) in a Multi-Agent System (MAS) for resolution of scheduling problems is proposed in this work. The learning module is based on Case-based Reasoning (CBR) and two different integration approaches are proposed. A computational study is made for comparing the two CBR integration perspectives. Finally, some conclusions are reached and future work outlined. © 2013, Springer Science+Business Media Dordrecht.
2013
Autores
Solteiro Pires, EJS; Tenreiro Machado, JAT; de Moura Oliveira, PBD;
Publicação
ENTROPY
Abstract
Multi-objective particle swarm optimization (MOPSO) is a search algorithm based on social behavior. Most of the existing multi-objective particle swarm optimization schemes are based on Pareto optimality and aim to obtain a representative non-dominated Pareto front for a given problem. Several approaches have been proposed to study the convergence and performance of the algorithm, particularly by accessing the final results. In the present paper, a different approach is proposed, by using Shannon entropy to analyze the MOPSO dynamics along the algorithm execution. The results indicate that Shannon entropy can be used as an indicator of diversity and convergence for MOPSO problems.
2013
Autores
Paulo Moura Oliveira; Paulo Novais; Luís Paulo Reis;
Publicação
Abstract
2013
Autores
Silva, S; Soares, S; Valente, A; Ribeiro, V;
Publicação
DIABETES TECHNOLOGY & THERAPEUTICS
Abstract
2013
Autores
Conceicao, A; Silva, AJ; Boaventura, J; Marinho, DA; Louro, H;
Publicação
JOURNAL OF HUMAN KINETICS
Abstract
The purpose of this paper was to examine the characteristics of waves generated when swimming with and without the use of Aquatrainer (R) snorkels. Eight male swimmers performed two maximal bouts of 25 m breaststroke, first without the use of a snorkel (normal condition) and then using a snorkel (snorkel condition). The body landmarks, centre of the mass velocity, stroke rate, stroke length, stroke index, and Strouhal number (St) were quantified. Fourier analysis was conducted to determine the frequency, amplitude, and phase characteristics of the vertical undulations. We also determined the undulation period, the first and second harmonic wave percentage, and the contribution of these components to the power of each of the wave signals. The first wave harmonics had a frequency of 0.76 Hz (normal condition) and 0.78 Hz (snorkel condition), and the second wave harmonics had a frequency of 1.52 Hz (normal condition) and 1.56 Hz (snorkel condition). Under the normal conditions, the wave amplitude was higher on the vertex (0.72 m) and cervical (0.32 m) than that produced under snorkel conditions (0.71 m and 0.28 m, respectively). The lowest values were found in the hip (0.03 m in normal conditions, and 0.02 m in snorkel conditions) and in the trunk (0.06 m in normal conditions, and 0.04 m in snorkel conditions). It can be concluded that snorkel use seems to lead to slight changes in the biomechanical pattern in swimming velocity, as well as several stroke mechanical variables.
2013
Autores
Cerveira, A; Baptista, J; Solteiro Pires, EJ;
Publicação
International Joint Conference SOCO'13-CISIS'13-ICEUTE'13 - Salamanca, Spain, September 11th-13th, 2013 Proceedings
Abstract
Nowadays, wind energy has an important role in the challenges of clean energy supply. It is the fastest growing energy source with a increasing annual rate of 20%. This scenario motivate the development of an optimization design tool to find optimal layout for wind farms. This paper proposes a mathematical model to find the best electrical interconnection configuration of the wind farm turbines and the substation. The goal is to minimize the installation costs, that include cable cost and cable installation costs, considering technical constraints. This problem corresponds to a capacitated minimum spanning tree with additional constraints. The methodology proposed is applied in a real case study and the results are compared with the ground solution. © Springer International Publishing Switzerland 2014.
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