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Publications

2012

Separability Analysis of Color Classes on Dermoscopic Images

Authors
Silva, CSP; Marcal, ARS; Pereira, MA; Mendonca, T; Rozeira, J;

Publication
IMAGE ANALYSIS AND RECOGNITION, PT II

Abstract
Dermoscopy is a non-invasive diagnostic technique for the in vivo observation of pigmented skin lesions used in dermatology. There is currently a great interest in the prospects of automatic image analysis methods for dermoscopy, both to provide quantitative information about a lesion, which can be of relevance for the clinician, and as a stand alone early warning tool. The standard approach in automatic dermoscopic image analysis has usually three stages: (i) segmentation, (ii) feature extraction and selection, (iii) lesion classification. This paper evaluates the potential of an alternative approach based on the Menzies method presence of 1 or more of 6 color classes, indicating that the lesion should be considered a potential melanoma. This method does not require stages (i) and (ii) - lesion segmentation and feature extraction. The Jeffries-Matusita and Transformed Divergence metrics were used to evaluate the color class separability. The preliminary results presented in this paper suggest that a system based on the Menzies method could provide valuable information for automatic dermoscopic image analysis.

2012

Towards Utility Maximization in Regression

Authors
Ribeiro, RP;

Publication
12TH IEEE INTERNATIONAL CONFERENCE ON DATA MINING WORKSHOPS (ICDMW 2012)

Abstract
Utilitybased learning is a key technique for addressing many real world data mining applications, where the costs/benefits are not uniform across the domain of the target variable. Still, most of the existing research has been focused on classification problems. In this paper we address a related problem. There are many relevant domains (e. g. ecological, meteorological, finance) where decisions are based on the forecast of a numeric quantity (i.e. the result of a regression model). The goal of the work on this paper is to present an evaluation framework for applications where the numeric outcome of a regression model may lead to different costs/benefits as a consequence of the actions it entails. The new metric provides a more informed estimate of the utility of any regression model, given the application-specific preference biases, and hence makes more reliable the comparison and selection between alternative regression models. We illustrate the objective of our evaluation methodology on a real-life application and also carry a set of experiments over a subset of our target regression tasks: the prediction of rare and extreme values. Results show the effectiveness of our proposed utility metric for identifying the models that perform better on this type of applications.

2012

Supplier's selection model based on an empirical study

Authors
Avila, P; Mota, A; Pires, A; Bastos, J; Putnik, G; Teixeira, J;

Publication
4TH CONFERENCE OF ENTERPRISE INFORMATION SYSTEMS - ALIGNING TECHNOLOGY, ORGANIZATIONS AND PEOPLE (CENTERIS 2012)

Abstract
The problem of selecting suppliers/partners is a crucial and important part in the process of decision making for companies that intend to perform competitively in their area of activity. The selection of supplier/partner is a time and resource-consuming task that involves data collection and a careful analysis of the factors that can positively or negatively influence the choice. Nevertheless it is a critical process that affects significantly the operational performance of each company. In this work, there were identified five broad selection criteria: Quality, Financial, Synergies, Cost, and Production System. Within these criteria, it was also included five sub-criteria. After the identification criteria, a survey was elaborated and companies were contacted in order to understand which factors have more weight in their decisions to choose the partners. Interpreted the results and processed the data, it was adopted a model of linear weighting to reflect the importance of each factor. The model has a hierarchical structure and can be applied with the Analytic Hierarchy Process (AHP) method or Value Analysis. The goal of the paper it's to supply a selection reference model that can represent an orientation/pattern for a decision making on the suppliers/partners selection process (C) 2012 Published by Elsevier Ltd. Selection and/or peer review under responsibility of CENTERIS/SCIKA - Association for Promotion and Dissemination of Scientific Knowledge

2012

Ancillary services market framework for voltage control in distribution networks with microgrids

Authors
Madureira, AG; Pecas Lopes, JAP;

Publication
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
In this paper, a proposal for an ancillary services (AS) market framework addressing voltage control in multi-microgrid systems is presented. This var market proposal for MV distribution systems can be adopted to involve Distributed Generation (DG) units and microgrids in AS provision. In the approach that was developed each player is given the opportunity to submit its bid to the var market and the market settlement is performed using an Optimal Power Flow (OPF) formulation in order to minimize the price of reactive power purchased by the Distribution System Operator (DSO). This market is based on var capacity use and runs daily after the scheduling of the generation units for a period of operation of one clay.

2012

Performance Measurement

Authors
Ferreira, PS; Cunha, PF; Maia Carneiro, L; Toscano, C;

Publication
Intelligent Non-hierarchical Manufacturing Networks - Poler/Intelligent Non-hierarchical Manufacturing Networks

Abstract

2012

A multi-agent based approach for intelligent smart grid management

Authors
Oliveira, P; Vale, Z; Morais, H; Pinto, T; Praca, I;

Publication
IFAC Proceedings Volumes (IFAC-PapersOnline)

Abstract
The spread and globalization of distributed generation (DG) in recent years has should highly influence the changes that occur in Electricity Markets (EMs). DG has brought a large number of new players to take action in the EMs, therefore increasing the complexity of these markets. Simulation based on multi-agent systems appears as a good way of analyzing players' behavior and interactions, especially in a coalition perspective, and the effects these players have on the markets. MASCEM - Multi-Agent System for Competitive Electricity Markets was created to permit the study of the market operation with several different players and market mechanisms. MASGriP - Multi-Agent Smart Grid Platform is being developed to facilitate the simulation of micro grid (MG) and smart grid (SG) concepts with multiple different scenarios. This paper presents an intelligent management method for MG and SG. The simulation of different methods of control provides an advantage in comparing different possible approaches to respond to market events. Players utilize electric vehicles' batteries and participate in Demand Response (DR) contracts, taking advantage on the best opportunities brought by the use of all resources, to improve their actions in response to MG and/or SG requests.

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