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Publicações

Publicações por LIAAD

2015

A Comparative Study of Regression and Classification Algorithms for Modelling Students' Academic Performance

Autores
Strecht, P; Cruz, L; Soares, C; Moreira, JM; Abreu, R;

Publicação
Proceedings of the 8th International Conference on Educational Data Mining, EDM 2015, Madrid, Spain, June 26-29, 2015

Abstract

2015

Estimating Fuel Consumption from GPS Data

Autores
Vilaca, A; Aguiar, A; Soares, C;

Publicação
PATTERN RECOGNITION AND IMAGE ANALYSIS (IBPRIA 2015)

Abstract
The road transportation sector is responsible for 87% of the human CO2 emissions. The estimation and prediction of fuel consumption plays a key role in the development of systems that foster the reduction of those emissions through trip planing. In this paper, we present a predictive regression model of instantaneous fuel consumption for diesel and gasoline light-duty vehicles, based on their instantaneous speed and acceleration and on road inclination. The parameters are extracted from GPS data, thus the models do not require data from dedicated vehicle sensors. We use data collected by 17 drivers during their daily commutes using the SenseMyCity crowdsensor. We perform an empyrical comparison of several regression algorithms for prediction across trips of the same vehicle and for prediction across vehicles. The results show that models trained for a vehicle show similar RMSE when are applied to other vehicles with similar characteristics. Relying on these results, we propose fuel type specific models that provide an accurate prediction for vehicles with similar characteristics to those on which the models were trained.

2015

Understanding Rankings of Financial Analysts

Autores
Aiguzhinov, A; Serra, APSFM; Soares, C;

Publicação
SSRN Electronic Journal

Abstract

2015

Are Rankings of Financial Analysts Useful to Investors?

Autores
Aiguzhinov, A; Serra, AP; Soares, C;

Publicação
SSRN Electronic Journal

Abstract

2015

A Bounded Neural Network for Open Set Recognition

Autores
Cardoso, DO; Franca, F; Gama, J;

Publicação
2015 INTERNATIONAL JOINT CONFERENCE ON NEURAL NETWORKS (IJCNN)

Abstract
Open set recognition is, more than an interesting research subject, a component of various machine learning applications which is sometimes neglected: it is not unusual the existence of learning systems developed on the top of closed-set assumptions, ignoring the error risk involved in a prediction. This risk is strictly related to the location in feature space where the prediction has to be made, compared to the location of the training data: the more distant the training observations are, less is known, higher is the risk. Proper handling of this risk can be necessary in various situation where classification and its variants are employed. This paper presents an approach to open set recognition based on an elaborate distance-like computation provided by a weightless neural network model. The results obtained in the proposed test scenarios are quite interesting, placing the proposed method among the current best ones.

2015

A framework for analysing dynamic communities in large-scale social networks

Autores
Cerqueira, V; Oliveira, M; Gama, J;

Publicação
ICEIS 2015 - 17th International Conference on Enterprise Information Systems, Proceedings

Abstract
Telecommunications companies must process large-scale social networks that reveal the communication patterns among their customers. These networks are dynamic in nature as new customers appear, old customers leave, and the interaction among customers changes over time. One way to uncover the evolution patterns of such entities is by monitoring the evolution of the communities they belong to. Large-scale networks typically comprise thousands, or hundreds of thousands, of communities and not all of them are worth monitoring, or interesting from the business perspective. Several methods have been proposed for tracking the evolution of groups of entities in dynamic networks but these methods lack strategies to effectively extract knowledge and insight from the analysis. In this paper we tackle this problem by proposing an integrated business-oriented framework to track and interpret the evolution of communities in very large networks. The framework encompasses several steps such as network sampling, community detection, community selection, monitoring of dynamic communities and rule-based interpretation of community evolutionary profiles. The usefulness of the proposed framework is illustrated using a real-world large-scale social network from a major telecommunications company.

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