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Publicações

2006

A fuzzy decision model for the active and reactive dispatch in market environment

Autores
Gomes, MH; Saraiva, JT;

Publicação
2006 9th International Conference on Probabilistic Methods Applied to Power Systems, PMAPS

Abstract
This paper presents a mathematical formulation for the active/reactive dispatch in electricity markets, recognizing that the typical sequential activities organized in terms of pool markets and the dispatch of ancillary services may lead to economic inefficiencies or technical difficulties. The developed model admits that it is known the purely economic pool dispatch and then it aims at dispatching reactive resources considering voltage and branch limit constraints and constraints reflecting the alternator capability curve. We also admitted that some constraints have a soft nature and used a symmetrical fuzzy decision formulation to model this aspect within an SLP based algorithm. Finally, the paper includes a case study based on the IEEE 24 bus/38 branch system to illustrate the results obtained with the developed approach. © Copyright KTH 2006.

2006

Preface

Autores
Liu, Z; Barbosa, L;

Publicação
Electronic Notes in Theoretical Computer Science

Abstract

2006

A structured methodology for Business Network design

Autores
Copani, G; Bosani, R; Tosatti, LM; Azevedo, A;

Publicação
2006 IEEE International Technology Management Conference, ICE 2006

Abstract
In the new manufacturing environment, a single enterprise does not often own all resources and skills to offer competitive solutions. Therefore, such enterprises become part of enterprise networks of independent core competencies in order to produce marketable products. Thus, Business Networking is an innovative business paradigm that can help companies to remain competitive in the market. Nevertheless, its practical implementation is very complicated because of the several dimensions that it involves, and, especially in network start up phase, because it is often left to the case and not managed with adequate methodologies and tools. The present paper proposes a structured methodology for long term business network design that is based on a network descriptive model and that should be applied by a 'network architect'. The proposed methodology has been developed and applied in the frame of KoBaS project funded through European Commission Program. © 2006 IEEE.

2006

Valuation of switchable tariff for wind energy

Autores
Yu, W; Sheble, GB; Lopes, JAP; Matos, MA;

Publicação
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
The current fixed tariff remuneration for wind energy is not compatible with the deregulation of the electric power industry. The time-varying and location-dependent value of renewable energy is not acknowledged. The newly announced switchable tariff for wind energy in the Spanish electricity market provides a promising solution to compensating renewable energy within the deregulated electric power industry. The new switchable tariff provides wind generators more flexibility in operating wind generation assets. Such flexibilities provide option value in coordinating the seasonality of wind energy, demand on electric power and electricity prices movement. This paper models and valuates the flexibility on switching tariff as real compound options for wind generators. Numerical examples valuate wind generation assets under fixed tariff, spot market price taking, and yearly and monthly switchable tariffs. The optimal switching strategies are identified. The impacts of the switchable tariff on sitting criteria and values of wind generation assets are investigated. An improvement on the yearly switchable tariff is suggested to further reduce the operation risk of wind generators and fully explore the efficiency provided by competitive electricity markets.

2006

Automatic speaker segmentation using multiple features and distance measures: A comparison of three approaches

Autores
Kotti, M; Martins, LGPM; Benetos, E; Cardoso, JS; Kotropoulos, C;

Publicação
2006 IEEE International Conference on Multimedia and Expo - ICME 2006, Vols 1-5, Proceedings

Abstract
This paper addresses the problem of unsupervised speaker change detection. Three systems based on the Bayesian Information Criterion (BIC) are tested. The first system investigates the AudioSpectrumCentroid and the AudioWaveformEnvelope features, implements a dynamic thresholding followed by a fusion scheme, and finally applies BIC. The second method is a real-time one that uses a metric-based approach employing the line spectral pairs and the BIC to validate a potential speaker change point. The third method consists of three modules. In the first module, a measure based on second-order statistics is used; in the second module, the Euclidean distance and T-2 Hotelling statistic are applied; and in the third module, the BIC is utilized. The experiments are carried out on a dataset created by concatenating speakers from the TIMIT database, that is referred to as the TIMIT data set. A comparison between the performance of the three systems is made based on t-statistics.

2006

A dynamic model for a settler unit using a kinetic formulation

Autores
Gomes, EF; Guimaraes, MML; Pinto, GA; Ribeiro, LM;

Publicação
Proceedings of the 5th International Conference on Engineering Computational Technology

Abstract
Design and control of mixer-settler batteries is very important for the technical and economical viability of the industrial processes of liquid-liquid extraction. Direct experimentation with these equipments is not always feasible, due to their complexity and cost. Computer simulation allows predicting the behaviour and optimizing the design of this type of equipments thus reducing costs. In previous works, we have already proposed a model to simulate the behaviour of a dispersion band in a gravitational settler unit of a mixer-settler system. Although the algorithm developed was able to simulate the band thickness for the transient state and the results obtained were in agreement with previously published results, some possible physical as well as conceptual limitations of this algorithm were detected. To overcome these problems, a new dynamic model using a kinetic formulation was proposed. This paper describes a new model for the shallow-layer settler unit which is able to describe the transient state of a liquid-liquid system, the hydrodynamic phenomena of drop-drop and drop-interface coalescence as well as the transport processes being explicitly taken into account. © 2006 Civil-Comp Press.

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