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Publications

Publications by CRACS

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

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.

2012

Identifying adverse drug events by relational learning

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

Publication
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

2012

Demand-driven clustering in relational domains for predicting adverse drug events

Authors
Davis, J; Costa, VS; Peissig, P; Caldwell, M; Berg, E; Page, D;

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

Abstract
Learning from electronic medical records (EMR) is challenging due to their relational nature and the uncertain dependence between a patient's past and future health status. Statistical relational learning is a natural fit for analyzing EMRs but is less adept at handling their inherent latent structure, such as connections between related medications or diseases. One way to capture the latent structure is via a relational clustering of objects. We propose a novel approach that, instead of pre-clustering the objects, performs a demand-driven clustering during learning. We evaluate our algorithm on three real-world tasks where the goal is to use EMRs to predict whether a patient will have an adverse reaction to a medication. We find that our approach is more accurate than performing no clustering, pre-clustering, and using expert-constructed medical heterarchies. Copyright 2012 by the author(s)/owner(s).

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