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Publicações

Publicações por CRACS

2010

Chess Revision: Acquiring the Rules of Chess Variants through FOL Theory Revision from Examples

Autores
Muggleton, S; Paes, A; Costa, VS; Zaverucha, G;

Publicação
INDUCTIVE LOGIC PROGRAMMING

Abstract
The game of chess has been a major testbed for research in artificial intelligence, since it requires focus on intelligent reasoning. Particularly, several challenges arise to machine learning systems when inducing a model describing legal moves of the chess, including the collection of the examples, the learning of a model correctly representing the official rules of the game, covering all the branches and restrictions of the correct moves, and the comprehensibility of such a model. Besides, the game of chess has inspired the creation of numerous variants, ranging from faster to more challenging or to regional versions of the game. The question arises if it is possible to take advantage of an initial classifier of chess as a starting point to obtain classifiers for the different variants. We approach this problem as an instance of theory revision from examples. The initial classifier of chess is inspired by a FOL theory approved by a chess expert and the examples are defined as sequences of moves within a game. Starting from a standard revision system, we argue that abduction and negation are also required to best address this problem. Experimental results show the effectiveness of our approach.

2010

Predicting the Start of Protein alpha-Helices Using Machine Learning Algorithms

Autores
Camacho, R; Ferreira, R; Rosa, N; Guimaraes, V; Fonseca, NA; Costa, VS; de Sousa, M; Magalhaes, A;

Publicação
ADVANCES IN BIOINFORMATICS

Abstract

2010

On the Implementation of the CLP(BN) Language

Autores
Costa, VS;

Publicação
PRACTICAL ASPECTS OF DECLARATIVE LANGUAGES, PROCEEDINGS

Abstract
The last few years have seen great interest in developing models that can describe real-life large-scale structured systems. A popular approach is to address these problems by using logic to describe the patterns or structure of the problems, and by using a calculus of probabilities to address the uncertainty so often found in real life situations. The CLP(BN) language is an extension of Prolog that allows the representation, inference, and learning of bayesian networks. The language was inspired on Koller's Probabilistic Relational Models, and is close to other probabilistic relational languages based in Prolog, such as Sato's PRISM. We present the implementation of CLP(BN), showing how bayesian networks are represented in CLP(BN) and presenting the implementation of three different inference algorithms: Gibbs Sampling, Variable Elimination, and Junction Trees. We show that these algorithms can be implemented effectively by using a matrix library and a graph manipulation library, and study how the system performs on real-life applications.

2010

Sequential Pattern Mining in Multi-relational Datasets

Autores
Ferreira, CA; Gama, J; Costa, VS;

Publicação
CURRENT TOPICS IN ARTIFICIAL INTELLIGENCE

Abstract
We present a framework designed to mine sequential temporal patterns from multi-relational databases. In order to exploit logic-relational information without using aggregation methodologies, we convert the multi-relational dataset into what we name a multi-sequence database. Each example in a multi-relational target table is coded into a sequence that combines intra-table and inter-table relational temporal information. This allows us to find heterogeneous temporal patterns through standard sequence miners. Our framework is grounded in the excellent results achieved by previous propositionalization strategies. We follow a pipelined approach, where we first use a sequence miner to find frequent sequences in the multi-sequence database. Next, we select the most interesting findings to augment the representational space of the examples. The most interesting sequence patterns are discriminative and class correlated. In the final step we build a classifier model by taking an enlarged target table as input to a classifier algorithm. We evaluate the performance of this work through a motivating application, the hepatitis multi-relational dataset. We prove the effectiveness of our methodology by addressing two problems of the hepatitis dataset.

2010

Temporal Anomaly Detection: An Artificial Immune Approach Based on T Cell Activation, Clonal Size Regulation and Homeostasis

Autores
Antunes, MJ; Correia, ME;

Publicação
ADVANCES IN COMPUTATIONAL BIOLOGY

Abstract
This paper presents an artificial immune system (AIS) based on Grossman's tunable activation threshold (TAT) for temporal anomaly detection. We describe the generic AIS framework and the TAT model adopted for simulating T Cells behaviour, emphasizing two novel important features: the temporal dynamic adjustment of T Cells clonal size and its associated homeostasis mechanism. We also present some promising results obtained with artificially generated data sets, aiming to test the appropriateness of using TAT in dynamic changing environments, to distinguish new unseen patterns as part of what should be detected as normal or as anomalous. We conclude by discussing results obtained thus far with artificially generated data sets.

2010

Patient Empowerment by the Means of Citizen-managed Electronic Health Records: Web 2.0 Health Digital Identity

Autores
Falcao Reis, F; Correia, ME;

Publicação
MEDICAL AND CARE COMPUNETICS 6

Abstract
With the advent of more sophisticated and comprehensive healthcare information systems, system builders are becoming more interested in patient interaction and what he can do to help to improve his own health care. Information systems play nowadays a crucial and fundamental role in hospital work-flows, thus providing great opportunities to introduce and improve upon "patient empowerment" processes for the personalization and management of Electronic Health Records (EHRs). In this paper, we present a patient's privacy generic control mechanisms scenarios based on the Extended OpenID (eOID), a user centric digital identity provider previously developed by our group, which leverages a secured OpenID 2.0 infrastructure with the recently released Portuguese Citizen Card (CC) for secure authentication in a distributed health information environment. eOID also takes advantage of Oauth assertion based mechanisms to implement patient controlled secure qualified role based access to his EHR, by third parties.

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