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Publicações

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

2012

Combining meta-learning with multi-objective particle swarm algorithms for svm parameter selection: An experimental analysis

Autores
Miranda, PBC; Prudencio, RBC; Carvalho, ACPLF; Soares, C;

Publicação
Proceedings - Brazilian Symposium on Neural Networks, SBRN

Abstract
Support Vector Machines (SVMs) have become a well succeeded technique due to the good performance it achieves on different learning problems. However, the SVM performance depends on adjustments of its parameters' values. The automatic SVM parameter selection is treated by many authors as an optimization problem whose goal is to find a suitable configuration of parameters for a given learning problem. This work performs a comparative study of combining Meta-Learning (ML) and Multi-Objective Particle Swarm Optimization (MOPSO) techniques for the SVM parameter selection problem. In this combination, configurations of parameters provided by ML are adopted as initial search points of the MOPSO techniques. Our hypothesis is that, starting the search with reasonable solutions will speed up the process performed by the MOPSO techniques. In our work, we implemented three MOPSO techniques applied to select two SVM parameters for classification. Our work's aim is to optimize the SVMs by seeking for configurations of parameters which maximize the success rate and minimize the number of support vectors (i.e., two objetive functions). In the experiments, the performance of the search algorithms using a traditional random initialization was compared to the performance achieved by initializing the search process using the ML suggestions. We verified that the combination of the techniques with ML obtained solutions with higher quality on a set of 40 classification problems. © 2012 IEEE.

2012

A Multi-Agent System to Help Farmville Players on Game Management Tasks

Autores
Neves, R; Reis, LP; Abreu, P; Faria, BM;

Publicação
INFORMATION SYSTEMS AND TECHNOLOGIES

Abstract
Nowadays social networks are used for various recreational purposes. It is believed that every day is spent on average two hours per user in these networks games. Farmville is an application relating to one of the most successful social networks: Facebook. Farmville is a game that allows each user to use a diverse set of actions available for managing a virtual farm. However, this management quickly becomes a boring and time consuming process and often the user quits the application. In this context this project main objective is the development of a multi-agent system able to assist the player in Farmville. The system will help the user in most of his management tasks on the farm. The use of the implemented system ensures greater progress in the game, because there is a decrease in the time spent in performing the tasks enabling the user to focus on the strategies for advancing in the game.

2012

Bus Bunching detection: A sequence mining approach

Autores
Moreira Matias, L; Ferreira, C; Gama, J; Mendes Moreira, J; De Sousa, JF;

Publicação
CEUR Workshop Proceedings

Abstract
Mining public transportation networks is a growing and explosive challenge due to the increasing number of information available. In highly populated urban zones, the vehicles can often fail the schedule. Such fails cause headway deviations (HD) between high-frequency bus pairs. In this paper, we propose to identify systematic HD which usually provokes the phenomenon known as Bus Bunching (BB). We use the PrefixSpan algorithm to accurately mine sequences of bus stops where multiple HD frequently emerges, forcing two or more buses to clump. Our results are promising: 1) we demonstrated that the BB origin can be modeled like a sequence mining problem where 2) the discovered patterns can easily identify the route schedule points to adjust in order to mitigate such events.

2012

Birefringence swap at the transition to hyperbolic dispersion in metamaterials

Autores
Custodio, LM; Sousa, CT; Ventura, J; Teixeira, JM; Marques, PVS; Araujo, JP;

Publicação
PHYSICAL REVIEW B

Abstract
The Bruggeman effective medium is used to study the transition to hyperbolic dispersion of visible light in thin-film metal-dielectric composite metamaterial of varying mixing proportion. This transition is experimentally demonstrated by the detection of the swap between the refracted birefringence components in fabricated composites of silver nanowires embedded in anodic aluminium oxide. Three refraction regimes are observed in a single composite using excitation radiation on both sides of the transition.

2012

The Power of Prediction: Robots that Read Intentions

Autores
Bicho, E; Erlhagen, W; Sousa, E; Louro, L; Hipolito, N; Silva, EC; Silva, R; Ferreira, F; Machado, T; Hulstijn, M; Maas, Y; de Bruijn, E; Cuijpers, RH; Newman Norlund, R; van Schie, H; Meulenbroek, RGJ; Bekkering, H;

Publicação
2012 IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS (IROS)

Abstract
Humans are experts in cooperating in a smooth and proactive manner. Action and intention understanding are critical components of efficient joint action. In the context of the EU Integrated Project JAST [16] we have developed an anthropomorphic robot endowed with these cognitive capacities. This project and respective robot (ARoS) is the focus of the video. More specifically, the results illustrate crucial cognitive capacities for efficient and successful human-robot collaboration such as goal inference, error detection and anticipatory action selection. Results were considered one of the ICT "success stories" [22].

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