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Publicações

Publicações por Vítor Santos Costa

2012

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

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

Publicação
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

Autores
Dovier, A; Costa, VS;

Publicação
THEORY AND PRACTICE OF LOGIC PROGRAMMING

Abstract

2010

Probabilistic inductive querying using problog

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

Publicação
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

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

Publicação
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.

2012

Identifying adverse drug events by relational learning

Autores
Page, D; Costa, VS; Natarajan, S; Barnard, A; Peissig, P; Caldwell, M;

Publicação
Proceedings of the National Conference on Artificial Intelligence

Abstract
The pharmaceutical industry, consumer protection groups, users of medications and government oversight agencies are all strongly interested in identifying adverse reactions to drugs. While a clinical trial of a drug may use only a thousand patients, once a drug is released on the market it may be taken by millions of patients. As a result, in many cases adverse drug events (ADEs) are observed in the broader population that were not identified during clinical trials. Therefore, there is a need for continued, post-marketing surveillance of drugs to identify previously-unanticipated ADEs. This paper casts this problem as a reverse machine learning task, related to relational subgroup discovery and provides an initial evaluation of this approach based on experiments with an actual EMR/EHR and known adverse drug events. Copyright

2011

Interactive Discriminative Mining of Chemical Fragments

Autores
Fonseca, NA; Pereira, M; Costa, VS; Camacho, R;

Publicação
INDUCTIVE LOGIC PROGRAMMING, ILP 2010

Abstract
Structural activity prediction is one of the most important tasks in chemoinformatics. The goal is to predict a property of interest given structural data on a set of small compounds or drugs. Ideally, systems that address this task should not just be accurate, but they should also be able to identify an interpretable discriminative structure which describes the most discriminant structural elements with respect to some target. The application of ILP in an interactive software for discriminative mining of chemical fragments is presented in this paper. In particular, it is described the coupling of an ILP system with a molecular visualisation software that allows a chemist to graphically control the search for interesting patterns in chemical fragments. Furthermore, we show how structural information, such as rings, functional groups such as carboxyls, amines, methyls, and esters, are integrated and exploited in the search.

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