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Publications

Publications by Vítor Santos Costa

2012

Predicting the secondary structure of proteins using Machine Learning algorithms

Authors
Camacho, R; Ferreira, R; Rosa, N; Guimaraes, V; Fonseca, NA; Costa, VS; de Sousa, M; Magalhaes, A;

Publication
INTERNATIONAL JOURNAL OF DATA MINING AND BIOINFORMATICS

Abstract
The functions of proteins in living organisms are related to their 3-D structure, which is known to be ultimately determined by their linear sequence of amino acids that together form these macromolecules. It is, therefore, of great importance to be able to understand and predict how the protein 3D-structure arises from a particular linear sequence of amino acids. In this paper we report the application of Machine Learning methods to predict, with high values of accuracy, the secondary structure of proteins, namely alpha-helices and beta-sheets, which are intermediate levels of the local structure.

2011

Fire! Firing Inductive Rules from Economic Geography for Fire Risk Detection

Authors
Vaz, D; Costa, VS; Ferreira, M;

Publication
INDUCTIVE LOGIC PROGRAMMING, ILP 2010

Abstract
Wildfires can importantly affect the ecology and economy of large regions of the world. Effective prevention techniques are fundamental to mitigate their consequences. The design of such preemptive methods requires a deep understanding of the factors that increase the risk of fire, particularly when we can intervene on these factors. This is the case for the maintenance of ecological balances in the landscape that minimize the occurrence of wildfires. We use an inductive logic programming approach over detailed spatial datasets: one describing the landscape mosaic and characterizing it in terms of its use; and another describing polygonal areas where wildfires took place over several years. Our inductive process operates over a logic term representation of vectorial geographic data and uses spatial predicates to explore the search space, leveraging the framework of Spatial-Yap, its multi-dimensional indexing and tabling extensions. We show that the coupling of a logic-based spatial database with an inductive logic programming engine provides an elegant and powerful approach to spatial data mining.

2002

From simulation to practice

Authors
Lopes, R; Castro, LF; Costa, VS;

Publication
Proceedings of the workshop on Memory system performance - MSP '02

Abstract

1998

VisAll: A universal tool to visualise the parallel execution of logic programs

Authors
Fonseca, N; Costa, VS; Dutra, ID;

Publication
LOGIC PROGRAMMING - PROCEEDINGS OF THE 1998 JOINT INTERNATIONAL CONFERENCE AND SYMPOSIUM ON LOGIC PROGRAMMING

Abstract
One of the most important advantages of logic programming systems is that they allow the transparent exploitation of parallelism. The different forms of parallelism available and the complex nature of logic programming applications present interesting problems to both the users and the developers of these systems. Graphical visualisation tools can give a particularly important contribution, as they are easier to understand than text based tools, and allow both for a general overview of an execution and for focusing on its important details. Towards these goals, we propose VisAll, anew tool to visualise the parallel execution of logic programs. VisAll benefits from a modular design centered in a graph that represents a parallel execution. A main graphical shell commands the different modules and presents VisAll as an unified system. Several input components, or translators, support the well-known VisAndor and VACE trace formats, plus a new format designed for independent and-parallel plus or-parallel execution in the SEA. Several output components, or visualisers, allow for different visualisations of the same execution.

2007

Selected papers from SBLP 2007: The 11th Brazilian Symposium on Programming Languages J.UCS special issue

Authors
Bigonha, RS; Musicante, MA; Pardo, A; Garcia, A; Martini, A; Moreira, AF; De Melo, ACV; Du Bois, AR; Santos, A; Camarao, C; Rubira, C; Braga, C; Naumann, D; Haeusler, EH; De Carvalho Junior, FH; Cafezeiro, I; Palsberg, J; Jeuring, J; Saraiva, J; Guimaraes, J; Labra, J; Fiadeiro, JL; Figueiredo, L; Barbosa, LS; Menezes, LC; Maia, M; De Valente, MTO; Bigonha, MAS; Benton, N; Rodriguez, N; Borba, P; Mosses, PD; Lins, RD; Cerqueira, R; Lima, RM; Ierusalimschy, R; Rigo, S; De Schneider, SM; Soares, S; Dascalu, S; Thompson, S; Vene, V; Costa, V; Iorio, VD;

Publication
JOURNAL OF UNIVERSAL COMPUTER SCIENCE

Abstract

2002

From simulation to practice: Cache performance study of a Prolog system

Authors
Lopes, R; Castro, LF; Costa, VS;

Publication
Proceedings of the 2002 Workshop on Memory System Performance, MSP 2002

Abstract
Progress in Prolog applications requires ever better performance and scalability from Prolog implementation technology. Most modern Prolog systems are emulator-based. Best performance thus requires both good emulator design and good memory performance. Indeed, Prolog applications can often spend hundreds of megabytes of data, but there is little work on understanding and quantifying the interactions between Prolog programs and the memory architecture of modern computers. In a previous study of Prolog systems we have shown through simulation that Prolog applications usually, but not always, have good locality, both for deterministic and non-deterministic applications. We also showed that performance may strongly depend on garbage collection and on database operations. Our analysis left two questions unanswered: how well do our simulated results holds on actual hardware, and how much did our results depend on a specific configuration? In this work we use several simulation parameters and profiling counters to improve understanding of Prolog applications. We believe that our analysis is of interest to any system implementor who wants to understand his or her own system's memory performance. Copyright 2002 ACM.

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