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Publications

Publications by Vítor Santos Costa

1999

COWL: Copy-on-write for logic programs

Authors
Costa, VS;

Publication
IPPS/SPDP 1999: 13TH INTERNATIONAL PARALLEL PROCESSING SYMPOSIUM & 10TH SYMPOSIUM ON PARALLEL AND DISTRIBUTED PROCESSING, PROCEEDINGS

Abstract
In order for parallel logic programming systems to become popular; they should serve the broadest range of applications. To achieve this goal, designers of parallel logic programming systems would like to exploit maximum parallelism for existing and novel applications. ideally by supporting both and-parallelism and or-parallelism. Unfortunately; the combination of both forms of parallelism is a hard problem, and available proposals cannot match the efficiency of; say, or-parallel only systems. We propose a novel approach to And/Or Parallelism in logic programs. Our initial observation is that stack copying, the most popular technique in or-parallel systems, does not work well with And/Or systems because network management is much more complex. Copying is also a significant problem in operating system where the copy-on-write (COW) has been dcl eloped to address the problem We demonstrate that this technique can also be applied to And/Or systems, and present both shared memory and distributed shared memory designs.

2012

Gene clusters as intersections of powers of paths

Authors
Costa, VS; Dantas, S; Sankoff, D; Xu, X;

Publication
J. Braz. Comp. Soc.

Abstract

2012

Unachievable region in precision-recall space and its effect on empirical evaluation

Authors
Boyd, K; Davis, J; Page, D; Costa, VS;

Publication
Proceedings of the 29th International Conference on Machine Learning, ICML 2012

Abstract
Precision-recall (PR) curves and the areas under them are widely used to summarize machine learning results, especially for data sets exhibiting class skew. They are often used analogously to ROC curves and the area under ROC curves. It is known that PR curves vary as class skew changes. What was not recognized before this paper is that there is a region of PR space that is completely unachievable, and the size of this region depends only on the skew. This paper precisely characterizes the size of that region and discusses its implications for empirical evaluation methodology in machine learning. Copyright 2012 by the author(s)/owner(s).

2012

Introduction to the 28th international conference on logic programming special issue

Authors
Dovier, A; Costa, VS;

Publication
THEORY AND PRACTICE OF LOGIC PROGRAMMING

Abstract

2010

Probabilistic inductive querying using problog

Authors
De Raedt, L; Kimmig, A; Gutmann, B; Kersting, K; Costa, VS; Toivonen, H;

Publication
Inductive Databases and Constraint-Based Data Mining

Abstract
We study how probabilistic reasoning and inductive querying can be combined within ProbLog, a recent probabilistic extension of Prolog. ProbLog can be regarded as a database system that supports both probabilistic and inductive reasoning through a variety of querying mechanisms. After a short introduction to ProbLog, we provide a survey of the different types of inductive queries that ProbLog supports, and show how it can be applied to the mining of large biological networks. © 2010 Springer Science+Business Media, LLC.

2012

A problog model for analyzing gene regulatory networks

Authors
Goncalves, A; Ong, IM; Lewis, JA; Santos Costa, V;

Publication
CEUR Workshop Proceedings

Abstract
Transcriptional regulation play an important role in every cellular decision. Gaining an understanding of the dynamics that govern how a cell will respond to diverse environmental cues is difficult using intuition alone. We introduce logic-based regulation models based on state-of-the-art work on statistical relational learning, to show that network hypotheses can be generated from existing gene expression data for use by experimental biologists.

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