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Publications

2010

Determining the best classification algorithm with recourse to sampling and metalearning

Authors
Brazdil, P; Leite, R;

Publication
Studies in Computational Intelligence

Abstract
Currently many classification algorithms exist and no algorithm exists that would outperform all the others. Therefore it is of interest to determine which classification algorithm is the best one for a given task. Although direct comparisons can be made for any given problem using a cross-validation evaluation, it is desirable to avoid this, as the computational costs are significant. We describe a method which relies on relatively fast pairwise comparisons involving two algorithms. This method is based on a previous work and exploits sampling landmarks, that is information about learning curves besides classical data characteristics. One key feature of this method is an iterative procedure for extending the series of experiments used to gather new information in the form of sampling landmarks. Metalearning plays also a vital role. The comparisons between various pairs of algorithm are repeated and the result is represented in the form of a partially ordered ranking. Evaluation is done by comparing the partial order of algorithm that has been predicted to the partial order representing the supposedly correct result. The results of our analysis show that the method has good performance and could be of help in practical applications. © 2010 Springer-Verlag Berlin Heidelberg.

2010

Representations for an iterative resource-based design approach

Authors
Dittmar, A; Harrison, MD;

Publication
EICS'10 - Proceedings of the 2010 ACM SIGCHI Symposium on Engineering Interactive Computing Systems

Abstract
This paper describes how the HOPS notation can be used to support Human Centered Design. It discusses the role of the notation in providing multiple design viewpoints. It demonstrates how the HOPS tool can be used to animate these viewpoints. Finally, HOPS is used to specify how the system provides information resources for user action. This approach to specifying plausible user behavior is contrasted with a task based approach. The HOPS based design techniques are illustrated through a process control example. © 2010 ACM.

2010

Constrains associated to e-business evolution

Authors
Morais, EP; Pires, JA; Goncalves, R;

Publication
E-Business Issues, Challenges and Opportunities for SMEs: Driving Competitiveness

Abstract
Technological advance of the last decades created an atmosphere in which the organizations are forced to look actively for new options for the cost reduction, in addition to, simultaneously, seeking to compete more effectively in their markets. This context requires focused, swift, more flexible and more competitive organizations which are forced, many times, to implement radical changes in the way they conduct business, employ people and use technology. Despite the recognition and the attention given to electronic business (or e-business) over the last years, this type of business hasn't yet achieved a desirable maturity stage. This problem, current and stated over the last years, demands research efforts so that a solution can be found to solve it. In this chapter, the authors explore a range of constraints which are suggested by the literature to influence e-business evolution, so that organizations could be better equipped in anticipating any difficulties while in progress through their e-business initiatives. © 2011, IGI Global.

2010

Active Testing Strategy to Predict the Best Classification Algorithm via Sampling and Metalearning

Authors
Leite, R; Brazdil, P;

Publication
ECAI 2010 - 19TH EUROPEAN CONFERENCE ON ARTIFICIAL INTELLIGENCE

Abstract
Currently many classification algorithms exist and there is no algorithm that would outperform all the others in all tasks. Therefore it is of interest to determine which classification algorithm is the best one for a given task. Although direct comparisons can be made for any given problem using a cross-validation evaluation, it is desirable to avoid this, as the computational costs are significant. We describe a method which relies on relatively fast pairwise comparisons involving two algorithms. This method exploits sampling landmarks, that is information about learning curves besides classical data characteristics. One key feature of this method is an iterative procedure for extending the series of experiments used to gather new information in the form of sampling landmarks. Metalearning plays also a vital role. The comparisons between various pairs of algorithm are repeated and the result is represented in the form of a partially ordered ranking. Evaluation is done by comparing the partial order of algorithm that has been predicted to the partial order representing the supposedly correct result. The results of our analysis show that the method has good performance and could be of help in practical applications.

2010

Grid interactive charging control for plug-in electric vehicles

Authors
Rei, RJ; Soares, FJ; Rocha Almeida, PM; Pecas Lopes, JA;

Publication
IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC

Abstract
This paper describes technical solutions to be adopted by Electric Vehicles (EV) battery grid interfaces, in order to get the provision of ancillary services to the grid. The developed solution exploits an EV battery charge control approach based in a grid cooperative response to frequency and/or voltage deviations. To be effective, those cooperative actions must result from both centralized/coordinated commands and local/individual EV charger response to the grid behaviour. In a scenario characterized by a massive deployment of EV, the adoption of such a solution allows an improvement on the power system dynamic behaviour, namely in small island grids. ©2010 IEEE.

2010

Scalable analysis of collective behaviour in smart service systems

Authors
Massink, M; Harrison, M; Latella, D;

Publication
Proceedings of the ACM Symposium on Applied Computing

Abstract
The long term vision of smart service systems in which electronic environments are made sensitive and responsive to the presence of, possibly many, people is gradually taking shape through a number of pilot projects. The purposes of such systems vary from intelligent homes that assist their inhabitants to make their lives more independent and comfortable to much larger environments such as airports in which people are provided with context aware, personalised, adaptive and anticipatory services that are most relevant for them given their location and their current activities. This paper is concerned with the exploration of scalable formal models that can address the collective behaviour of a large number of people moving through a smart environment. © 2010 ACM.

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