2011
Authors
Gonçalves, CT; Camacho, R; Oliveira, EC;
Publication
IJKDB
Abstract
2011
Authors
Santos, A; Camacho, R;
Publication
Proceedings of the IADIS European Conference on Data Mining 2011, Part of the IADIS Multi Conference on Computer Science and Information Systems 2011, MCCSIS 2011
Abstract
This paper presents the user friendly features of a Web site for Multi-Relational Data Mining (MRDM) problems in Molecular Biology and Drug Design. The purpose of the Web site is to allow any non expert in MRDM to perform a data analysis task using an Inductive Logic Programming (ILP) system without any knowledge of the workings of such systems. With that aim, the site provides an extensive library of predicates for the user to construct in an easy way the required data set's background knowledge. The set of predicates is automatically extended, using web-services technology, by searching, in a user transparent way, web sites of other research groups implementing the same Web site architecture. The site also implements a module that allows the user to execute a series of data analysis experiments without any knowledge of the ILP system's parameters and the Prolog encoding of the induced models. Prolog models are translated to English before being shown to the user and an interface, using a set of menus expressing "qualitative options", allows the user to control the updating of the induced models. The Web site has, so far, received positive feedback from the chemist elements of the project team in a drug design problem were we have applied it. © 2011 IADIS.
2011
Authors
Rocha, A; Henriques, MR; Lopes, JC; Camacho, R; Klein, M; Modena, G; Van de Ven, P; McGovern, E; Tousset, E; Gauthier, T; Warmerdam, L;
Publication
2012 25TH INTERNATIONAL SYMPOSIUM ON COMPUTER-BASED MEDICAL SYSTEMS (CBMS)
Abstract
FP7 ICT4Depression project aims at providing a set of tools to,further improve both patient outcome and increase of access to treatment of the patients suffering from major depression. This article describes the Information Systems (IS) architecture used in the project. ICT4Depression uses a service oriented architecture as means of bringing together different kinds of information concerning the patient, the therapeutic modules he is advised to follow and the sensors used to assess his status.
2011
Authors
Roque, LAC; Fontes, DBMM; Fontes, FACC;
Publication
EXPERIMENTAL ALGORITHMS
Abstract
A Biased Random Key Genetic Algorithm (BRKGA) is proposed to find solutions for the unit commitment problem. In this problem, one wishes to schedule energy production on a given set of thermal generation units in order to meet energy demands at minimum cost, while satisfying a set of technological and spinning reserve constraints. In the BRKGA, solutions are encoded by using random keys, which are represented as vectors of real numbers in the interval [0, 1]. The GA proposed is a variant of the random key genetic algorithm, since bias is introduced in the parent selection procedure, as well as in the crossover strategy. Tests have been performed on benchmark large-scale power systems of up to 100 units for a 24 hours period. The results obtained have shown the proposed methodology to be an effective and efficient tool for finding solutions to large-scale unit commitment problems. Furthermore, from the comparisons made it can be concluded that the results produced improve upon some of the best known solutions.
2011
Authors
Pereira, PA; Fontes, FACC; Fontes, DBMM;
Publication
OPERATIONS RESEARCH PROCEEDINGS 2010
Abstract
We propose a Hybrid Genetic Algorithm (HGA) for a combinatorial optimization problem, motivated by, and a simplification of, a TV Self-promotion Assignment Problem. Given the weekly self-promotion space (a set of TV breaks with known duration) and a set of products to promote, the problem consists of assigning the products to the breaks in the "best" possible way. The objective is to maximize contacts in the target audience for each product, whist satisfying all constraints. The HGA developed incorporates a greedy heuristic to initialize part of the population and uses a repair routine to guarantee feasibility of each member of the population. The HGA works on a simplified version of the problem that, nevertheless, maintains its essential features. The proposed simplified problem is a binary programming problem that has similarities with other known combinatorial optimization problems, such as the assignment problem or the multiple knapsack problem, but has some distinctive features that characterize it as a new problem. Although we are mainly interested in solving problems of large dimension (of about 200 breaks and 50 spots), the quality of the solution has been tested on smaller dimension problems for which we are able to find an exact global minimum using a branch-and-bound algorithm. For these smaller dimension problems we have obtained solutions, on average, within 1% of the optimal solution value.
2011
Authors
Monteiro, MSR; Fontes, DBMM; Fontes, FACC;
Publication
GECCO-2011: PROCEEDINGS OF THE 13TH ANNUAL GENETIC AND EVOLUTIONARY COMPUTATION CONFERENCE
Abstract
In this work we address the Singe-Source Uncapacitated Minimum Cost Network Flow Problem with concave cost functions. Given that this problem is of a combinatorial nature and also that the total costs are nonlinear, we propose a hybrid heuristic to solve it. In this type of algorithms one usually tries to manage two conflicting aspects of searching behaviour: exploration, the algorithm's ability to search broadly through the search space; and exploitation, the algorithm ability to search locally around good solutions that have been found previously. In our case, we use an Ant Colony Optimization algorithm to mainly deal with the exploration, and a Local Search algorithm to cope with the exploitation of the search space. Our method proves to be very efficient while solving both small and large size problem instances. The problems we have used to test the algorithm were previously solved by other authors using other population based heuristics and our algorithm was able to improve upon their results, both in terms of computing time and solution quality.
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