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Publications

2012

GUIsurfer: A Reverse Engineering Framework for User Interface Software

Authors
Creissac, J; Saraiva, J; Silva, C; Carlos, J;

Publication
Reverse Engineering - Recent Advances and Applications

Abstract

2012

Multi-objective integrated production and distribution planning of perishable products

Authors
Amorim, P; Guenther, HO; Almada Lobo, B;

Publication
INTERNATIONAL JOURNAL OF PRODUCTION ECONOMICS

Abstract
Integrated production and distribution planning have received a lot of attention throughout the years and its economic advantages are well documented. However, for highly perishable products this integrated approach has to include, further than the economic aspects, the intangible value of freshness. We explore, through a multi-objective framework, the advantages of integrating these two intertwined planning problems at an operational level. We formulate models for the case where perishable goods have a fixed and a loose shelf-life (i.e. with and without a best-before-date). The results show that the economic benefits derived from using an integrated approach are much dependent on the freshness level of products delivered.

2012

Localization of Mobile Robots Using an Extended Kalman Filter in a LEGO NXT

Authors
Pinto, M; Moreira, AP; Matos, A;

Publication
IEEE TRANSACTIONS ON EDUCATION

Abstract
The inspiration for this paper comes from a successful experiment conducted with students in the "Mobile Robots" course in the fifth year of the integrated Master's program in the Department of Electrical and Computer Engineering, Faculty of Engineering, University of Porto (FEUP), Porto, Portugal. One of the topics in this Mobile Robots course is "Localization of Mobile Robots using the Extended Kalman Filter in a LEGO NXT," which gives the students the opportunity to study the concepts of localization. This experiment comes within the framework of teaching localization concepts in mobile robotics and focuses primarily on explaining the Kalman filter concept. It involves a specific tool developed by the authors and based on LEGO NXT technology. The work presented here could be a helpful guide for teaching concepts related to localization in mobile robotics to ensure adequate understanding of the concept and of the use of the extended Kalman filter (EKF). The LegoFeup robot described here was built using a LEGO Mindstorms NXT and tested both in simulation and in real scenarios. Based on the results obtained, the authors concluded that the developed tool is effective in motivating students. The implementation of the tool, the structure of the Mobile Robots course, and the criteria for student assessment are described in this paper.

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).

2012

A survey on learning from data streams: current and future trends

Authors
Gama, J;

Publication
Progress in AI

Abstract
Nowadays, there are applications in which the data are modeled best not as persistent tables, but rather as transient data streams. In this article, we discuss the limitations of current machine learning and data mining algorithms. We discuss the fundamental issues in learning in dynamic environments like continuously maintain learning models that evolve over time, learning and forgetting, concept drift and change detection. Data streams produce a huge amount of data that introduce new constraints in the design of learning algorithms: limited computational resources in terms of memory, cpu power, and communication bandwidth. We present some illustrative algorithms, designed to taking these constrains into account, for decision-tree learning, hierarchical clustering and frequent pattern mining. We identify the main issues and current challenges that emerge in learning from data streams that open research lines for further developments. © 2011 Springer-Verlag.

2012

Determination of Microcystin-LR in waters in the subnanomolar range by sol-gel imprinted polymers on solid contact electrodes

Authors
Queiros, RB; Noronha, JP; Marques, PVS; Fernandes, JS; Sales, MGF;

Publication
ANALYST

Abstract
The present work reports new sensors for the direct determination of Microcystin-LR (MC-LR) in environmental waters. Both selective membrane and solid contact were optimized to ensure suitable analytical features in potentiometric transduction. The sensing layer consisted of Imprinted Sol-Gel (ISG) materials capable of establishing surface interactions with MC-LR. Non-Imprinted Sol-Gel (NISG) membranes were used as negative control. The effects of an ionic lipophilic additive, time of sol-gel polymerization, time of extraction of MC-LR from the sensitive layer, and pH were also studied. The solid contact was made of carbon, aluminium, titanium, copper or nickel/chromium alloys (80 : 20 or 90 : 10). The best ISG sensor had a carbon solid contact and displayed average slopes of 211.3 mV per decade, with detection limits of 7.3 x 10(-10) M, corresponding to 0.75 mu g L-1. It showed linear responses in the range of 7.7 x 10(-10) to 1.9 x 10(-9) M of MC-LR (corresponding to 0.77-2.00 mu g L-1), thus including the limiting value for MC-LR in waters (1.0 mu g L-1). The potentiometric-selectivity coefficients were assessed by the matched potential method for ionic species regularly found in waters up to their limiting levels. Chloride (Cl-) showed limited interference while aluminium (Al3+), ammonium (NH4+), magnesium (Mg2+), manganese (Mn2+), sodium (Na+), and sulfate (SO42-) were unable to cause the required potential change. Spiked solutions were tested with the proposed sensor. The relative errors and standard deviation obtained confirmed the accuracy and precision of the method. It also offered the advantages of low cost, portability, easy operation and suitability for adaptation to flow methods.

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