2003
Authors
Fontes, DBMM; Hadjiconstantinou, E; Christofides, N;
Publication
NETWORKS
Abstract
In this paper, we describe a heuristic algorithm based on local search for the Single-Source Uncapacitated (SSU) concave Minimum-Cost Network Flow Problem (MCNFP). We present a new technique for creating different and informed initial solutions to restart the local search, thereby improving the quality of the resulting feasible solutions (upper bounds). Computational results on different classes of test problems indicate the effectiveness of the proposed method in generating basic feasible solutions for the SSU concave MCNFP very near to a global optimum. A maximum upper bound percentage error of 0.07% is reported for all problem instances for which an optimal solution has been found by a branch-and-bound method. (C) 2003 Wiley Periodicals, Inc.
2003
Authors
Resende, FO; Lopes, JAP; Teiga, FJ;
Publication
Informacion Tecnologica
Abstract
The aim of this work was the development of a new approach to find an optimal solution for the internal electrical network configuration of a wind park. The new approach, described in this paper, allows solving the electrical design problem of a wind park, trying to find simultaneously the best topology for the network and for the cable speciifciations. The problem is considered as a global optimization problem (minimisation of the investments and operation costs), in which reliability is also taken into account. For that purpose, an evolutionary approach based on nitching type methods was used to develop a design tool able to find a reduced set of good solutions to be presented to the design engineers for further decision. This approach was tested with success in the project of a real wind park and the results proved to be satisfactory.
2003
Authors
Pinto, JS;
Publication
Electronic Notes in Theoretical Computer Science
Abstract
This paper presents an implementation device for the weak reduction of interaction nets to interface normal form. The results produced by running several benchmarks are given, suggesting that weak reduction greatly improves the performance of the interaction combinators-based implementation of the ?-calculus. © 2003 Published by Elsevier Science B.V.
2003
Authors
Alves, S; Florido, M;
Publication
LOGIC BASED PROGRAM SYNTHESIS AND TRNSFORMATION
Abstract
We identify a restricted class of terms of the lambda calculus, here called weak linear, that includes the linear lambda-terms keeping their good properties of strong normalization, non-duplicating reductions and typability in polynomial time. The advantage of this class over the linear lambda-calculus is the possibility of transforming general terms into weak linear terms with the same normal form. We present such transformation and prove its correctness by showing that it preserves normal forms.
2003
Authors
Cunha, JPS; Vollmar, C; Li, Z; Fernandes, J; Feddersen, B; Noachtar, S;
Publication
PROCEEDINGS OF THE 25TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-4: A NEW BEGINNING FOR HUMAN HEALTH
Abstract
In Epilepsy, seizure semiology analysis is routinely used for diagnostic purpose. The behavior of the patient during seizures is usually evaluated by expert qualitative observation where several signs are identified. In the clinical literature, several ictal phenomena are described but still involved in controversy. In this paper, we present our effort to establish a quantified movement analysis method to be widely used as an additional tool to clarify this controversy.
2003
Authors
dos Santos, PL; de Carvalho, JLM;
Publication
42ND IEEE CONFERENCE ON DECISION AND CONTROL, VOLS 1-6, PROCEEDINGS
Abstract
In this paper we find some linear dependencies on the matrices used for B and D estimation by the Van Overschee and De Moore non-biased versions of the Combined Deterministic-Stochastic Subspace Identification algorithms (CDSSI). These dependencies allow us to formulate algorithms that significantly improve the numerical efficiency on estimating these parameters without loss of accuracy. Experiences performed on practical data sets showed that the robust versions of these algorithms are twice as fast as the robust version proposed by Van Overschee and De Moore.
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