Cookies Policy
The website need some cookies and similar means to function. If you permit us, we will use those means to collect data on your visits for aggregated statistics to improve our service. Find out More
Accept Reject
  • Menu
Publications

Publications by CRACS

2005

Dynamic mixed-strategy evaluation of tabled logic programs

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

Publication
LOGIC PROGRAMMING, PROCEEDINGS

Abstract
Tabling is an implementation technique that improves the declarativeness and expressiveness of Prolog by reusing answers to subgoals. During tabled execution, several decisions have to be made. These are determined by the scheduling strategy. Whereas a strategy can achieve very good performance for certain applications, for others it might add overheads and even lead to unacceptable inefficiency. The ability of using multiple strategies within the same evaluation can be a means of achieving the best possible performance. In this work, we present how the YapTab system was designed to support dynamic mixed-strategy evaluation of the two most successful tabling scheduling strategies: batched scheduling and local scheduling.

2005

Strategies to parallelize ILP systems

Authors
Fonseca, NA; Silva, F; Camacho, R;

Publication
INDUCTIVE LOGIC PROGRAMMING, PROCEEDINGS

Abstract
It is well known by Inductive Logic Programming (ILP) practioners that ILP systems usually take a long time to find valuable models (theories). The problem is specially critical for large datasets, preventing ILP systems to scale up to larger applications. One approach to reduce the execution time has been the parallelization of ILP systems. In this paper we overview the state-of-the-art on parallel ILP implementations and present work on the evaluation of some major parallelization strategies for ILP. Conclusions about the applicability of each strategy are presented.

2005

A software framework for rapid prototyping of run-time systems for mobile calculi

Authors
Bettini, L; De Nicola, R; Falassi, D; Lacoste, M; Lopes, L; Oliveira, L; Paulino, H; Vasconcelos, VT;

Publication
GLOBAL COMPUTING

Abstract
We describe the architecture and the implementation of the MIKADO software framework, that we call IMC (Implementing Mobile Calculi). The framework aims at providing the programmer with primitives to design and implement run-time systems for distributed process calculi. The paper describes the four main components of abstract machines for mobile calculi (node topology, naming and binding, communication protocols and mobility) that have been implemented as Java packages. The paper also contains the description of a prototype implementation of a run-time system for the Distributed Pi-Calculus relying on the presented framework.

2005

MiKO - Mikado Koncurrent Objects

Authors
Martins, F; Salvador, L; Vasconcelos, VT; Lopes, LMB;

Publication
Foundations of Global Computing, 20.-25. February 2005

Abstract

2005

On applying tabling to inductive logic programming

Authors
Rocha, R; Fonseca, N; Costa, VS;

Publication
MACHINE LEARNING: ECML 2005, PROCEEDINGS

Abstract
Inductive Logic Programming (ILP) is an established subfield of Machine Learning. Nevertheless, it is recognized that efficiency and scalability is a major obstacle to an increased usage of ILP systems in complex applications with large hypotheses spaces. In this work, we focus on improving the efficiency and scalability of ILP systems by exploring tabling mechanisms available in the underlying Logic Programming systems. Tabling is an implementation technique that improves the declarativeness and performance of Prolog systems by reusing answers to subgoals. To validate our approach, we ran the April ILP system in the YapTab Prolog tabling system using two well-known datasets. The results obtained show quite impressive gains without changing the accuracy and quality of the theories generated.

2005

Coupling OPTYAP with a database system

Authors
Ferreira, M; Rocha, R;

Publication
AC 2005, Proceedings of the IADIS International Conference on Applied Computing, Algarve, Portugal, February 22-25, 2005, 2 Volumes

Abstract

  • 188
  • 208