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Publications

Publications by CRACS

2003

An empirical evaluation of bagging in inductive logic programming

Authors
De Dutra, IC; Page, D; Costa, VS; Shavlik, J;

Publication
Lecture Notes in Artificial Intelligence (Subseries of Lecture Notes in Computer Science)

Abstract
Ensembles have proven useful for a variety of applications, with a variety of machine learning approaches. While Quinlan has applied boosting to FOIL, the widely-used approach of bagging has never been employed in ILP. Bagging has the advantage over boosting that the different members of the ensemble can be learned and used in parallel. This advantage is especially important for ILP where run-times often are high. We evaluate bagging on three different application domains using the complete-search ILP system, Aleph. We contrast bagging with an approach where we take advantage of the non-determinism in ILP search, by simply allowing Aleph to run multiple times, each time choosing "seed" examples at random.

2003

Applying Scheduling by Edge Reversal to Constraint Partitioning

Authors
Pereira, MR; Vargas, PK; França, FMG; Castro, MCSd; Dutra, IdC;

Publication
15th Symposium on Computer Architecture and High Performance Computing (SBAC-PAD 2003), 10-12 November 2003, Sao Paulo, Brazil

Abstract

2003

Linearization by program transformation

Authors
Alves, S; Florido, M;

Publication
LOGIC BASED PROGRAM SYNTHESIS AND TRNSFORMATION

Abstract
We identify a restricted class of terms of the lambda calculus, here called weak linear, that includes the linear lambda-terms keeping their good properties of strong normalization, non-duplicating reductions and typability in polynomial time. The advantage of this class over the linear lambda-calculus is the possibility of transforming general terms into weak linear terms with the same normal form. We present such transformation and prove its correctness by showing that it preserves normal forms.

2002

P-3: Parallel peer to peer an - Internet parallel programming environment

Authors
Oliveira, L; Lopes, L; Silva, F;

Publication
WEB ENGINEERING AND PEER TO PEER COMPUTING

Abstract
P-3 is a next-generation Internet computing platform, building upon other experiments and implementing new ideas for high-performance parallel computing in the Internet environment. This paper describes its run-time system, programming model and how it compares to current state-of-the-art systems.

2002

Achieving Scalability in Parallel Tabled Logic Programs

Authors
Rocha, R; Silva, FMA; Costa, VS;

Publication
16th International Parallel and Distributed Processing Symposium (IPDPS 2002), 15-19 April 2002, Fort Lauderdale, FL, USA, CD-ROM/Abstracts Proceedings

Abstract
Tabling or memoing is a technique where one stores intermediate answers to a problem so that they can be reused in further calls. Tabling is of interest to logic programming because it addresses some of the most significant weaknesses of Prolog. Namely, it can guarantee termination for programs with the bounded term-size property. Tabled programs exhibit a more complex execution mechanism than traditional Prolog's left-to-right search with backtracking. The reason is that Prolog programs are highly recursive and generate multiple answers. This rather involved execution mechanism requires a more complex implementation than traditional Prolog. The declarative nature of tabled logic programming suggests that it might be amenable to parallel execution. On the other hand, the complexity of the tabling mechanism, and the existence of a shared resource, the table, argues that parallelism might be limited, and that performance for real applications might never scale. In this work we prove that parallel tabling is indeed scalable for real applications by experimenting the OPTYap parallel tabled system on a scalable shared-memory machine. © 2002 IEEE.

2002

Using Constraint Logic Programming to Generate Drills in Mathematics

Authors
Tomás, AP; Leal, JP; Vasconcelos, P;

Publication
AGP 2002: Proceedings of the Joint Conference on Declarative Programming, APPIA-GULP-PRODE, Madrid, Spain, September 16-18, 2002.

Abstract

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