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Publications

Publications by João Gama

2010

Resource Aware Distributed Knowledge Discovery

Authors
Gama, J; Cornuéjols, A;

Publication
Ubiquitous Knowledge Discovery - Challenges, Techniques, Applications

Abstract
In the introduction it was argued that ubiquitous knowledge discovery systems have to be able to sense their environment and receive data from other devices, to adapt continuously to changing environmental conditions (including their own condition) and evolving user habits and need be capable of predictive self-diagnosis. In the last chapter, resource constraints arising from ubiquitous environments have been discussed in some detail. It has been argued that algorithms have to be resource-aware because of real-time constraints and of limited computing and battery power as well as communication resources. © 2010 Springer-Verlag.

1995

Characterization of Classification Algorithms

Authors
Gama, J; Brazdil, P;

Publication
Progress in Artificial Intelligence, 7th Portuguese Conference on Artificial Intelligence, EPIA '95, Funchal, Madeira Island, Portugal, October 3-6, 1995, Proceedings

Abstract
This paper is concerned with the problem of characterization of classification algorithms. The aim is to determine under what circumstances a particular classification algorithm is applicable. The method used involves generation of different kinds of models. These include regression and rule models, piecewise linear models (model trees) and instance based models. These are generated automatically on the basis of dataset characteristics and given test results. The lack of data is compensated for by various types of preprocessing. The models obtained are characterized by quantifying their predictive capability and the best models are identified. © Springer-Verlag Berlin Heidelberg 1995.

1997

Search-based class discretization

Authors
Torgo, L; Gama, J;

Publication
MACHINE LEARNING : ECML-97

Abstract
We present a methodology that enables the use of classification algorithms on regression tasks. We implement this method in system RECLA that transforms a regression problem into a classification one and then uses an existent classification system to solve this new problem. The transformation consists of mapping a continuous variable into an ordinal variable by grouping its values into an appropriate set of intervals. We use misclassification costs as a means to reflect the implicit ordering among the ordinal values of the new variable. We describe a set of alternative discretization methods and, based on our experimental results, justify the need for a search-based approach to choose the best method. Our experimental results confirm the validity of our search-based approach to class discretization, and reveal the accuracy benefits of adding misclassification costs.

2009

Advanced Data Mining and Applications

Authors
Huang, R; Yang, Q; Pei, J; Gama, J; Meng, X; Li, X;

Publication
Lecture Notes in Computer Science

Abstract

2010

Knowledge Discovery from Sensor Data

Authors
Gaber, MM; Vatsavai, RR; Omitaomu, OA; Gama, J; Chawla, NV; Ganguly, AR;

Publication
Lecture Notes in Computer Science

Abstract

2011

Advances in Intelligent Data Analysis X

Authors
Gama, J; Bradley, E; Hollmén, J;

Publication
Lecture Notes in Computer Science

Abstract

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