2009
Authors
Carvalhosa, A; Machado, P; Sousa, A; Alves, JC;
Publication
IECON: 2009 35TH ANNUAL CONFERENCE OF IEEE INDUSTRIAL ELECTRONICS, VOLS 1-6
Abstract
The goal of the "Soft Core Robot" project is to set the way for a robot with minimalistic component and pin count, based on custom computing. Additionally, the "Joint Wheel Motion Controller" specifically takes advantage of custom computing in order to privilege angular precision over linear velocity which is interesting for some applications including mobile robotics. The proposed "Soft Core Robot" is expected to produce a small but very powerful and versatile robot. The chosen processing platform is based on a FPGA plus Microprocessor in the same chip. The proposed example application is the Fire Fighting contest at Instituto Politecnico da Guarda, in Portugal. The Joint Wheel Controller is not yet fully operational but results for the control of a single motor are presented. The overall status of the project is addressed, as well as the pros and cons of the approaches taken.
2009
Authors
Mendes, JM; Bepperling, A; Pinto, J; Leitao, P; Restivo, F; Colombo, AW;
Publication
2009 IEEE 33RD INTERNATIONAL COMPUTER SOFTWARE AND APPLICATIONS CONFERENCE, VOLS 1 AND 2
Abstract
Service-orientation represents a new wave Of features and solutions by bringing closer Information Technology to the industrial domain, particularly factory shop floors. The service-oriented automation software entities (designated here by bots) used in such approach requires a short set of methodologies and software targeting their specification for both computer systems and embedded automation devices. The present work explains the adopted methodologies and software developments for the engineering of service-based automation systems. The main contents focus on the specification of a framework for the development of bots and supporting engineering tools that are part of the Continuum project. The paper also does an overview over the engineering steps from the system design to the operation, and focuses the importance of the maintenance of automation bots. Such applications will contribute to decrease the development time and reduce the components' interdependency, offering enough flexibility for automatic reconfiguration of shop-floor layouts.
2009
Authors
Moura, P;
Publication
PRACTICAL ASPECTS OF DECLARATIVE LANGUAGES
Abstract
This paper identifies potential security loopholes in the implementation of support for meta-predicates Closing these loopholes depends on three conditions: a clear distinction between closures and goals, support for an extended meta-predicate directive that allows the specification of closures, and the availability of the call/2-N family of built-in meta-predicates. These conditions provide the basis for a set of simple safety rules that allows meta-predicates to be securely supported. These safety rules are currently implemented by Logtalk, all object-oriented logic programming language, and may also be applied in the context of Prolog predicate-based module systems. Experimental results illustrate how these rules can prevent several security problems, including accidental or malicious changes to the original meta-predicate arguments and bypassing of predicate scope rules and predicate scope directives.
2009
Authors
Mendes Moreira, J; Jorge, AM; Soares, C; de Sousa, JF;
Publication
MACHINE LEARNING AND DATA MINING IN PATTERN RECOGNITION
Abstract
Integration methods for ensemble learning can use two different approaches: combination or selection. The combination approach (also called fusion) consists on the combination of the predictions obtained by different models in the ensemble to obtain the final ensemble predication. The selection approach selects one (or more) models from the ensemble according to the prediction performance of these models on similar data from the validation set. Usually, the method to select similar data is the k-nearest neighbors with the Euclidean distance. In this paper we discuss other approaches to obtain similar data for the regression problem. We show that using similarity measures according to the target values improves results. We also show that selecting dynamically several models for the prediction task increases prediction accuracy comparing to the selection of just one model.
2009
Authors
Richter Trummer, V; Tavares, SMO; Peixoto, DFC; Silva, SF; Frazao, O; Moreira, PMGP; De Castro, PMST;
Publication
AES-ATEMA International Conference Series - Advances and Trends in Engineering Materials and their Applications
Abstract
Welding process monitoring using fibre Bragg grating (FBG) sensor technology is a promising technique to measure temperature and strain during the fabrication process. Examples of FBG sensor based temperature and strain measurements in butt-welding of plates are presented in this paper. In order to be able to measure strain and/or temperature it is however necessary to calibrate these instruments for accurate measurement results. In the present work calibration for strain measurements at constant temperature using a four point bending test is performed. This type of mechanical test allows enough space for instrumentation between the inner rollers. A finite element model is made using Abaqus for comparison and strain gauges are used for calibration purposes. Temperature calibration was carried out using an oven. The FBG sensors' measurements were calibrated with data obtained by thermocouples. Tests on welds are presented and the possible impact of this monitoring technology is briefly discussed in the light of process optimization and subsequent structural health monitoring. © AES-Advanced Engineering Solutions.
2009
Authors
Freitas, M; Sousa, AA; Coelho, A;
Publication
GRAPP 2009: PROCEEDINGS OF THE FOURTH INTERNATIONAL CONFERENCE ON COMPUTER GRAPHICS THEORY AND APPLICATIONS
Abstract
Nowadays, there is a wide range of commercial LBMS (Location-Based Mobile Services) available in the market, mainly in the form of GPS-based navigation solutions, and a trend towards the display of 3D maps can be clearly observed. Given the complete disparity of ideas and a visible commercial orientation in the industry, the study of the visualisation aspects that influence user performance and experience in the exploration of urban environments using 3D maps becomes an important issue. In this work, a generic conceptual framework is proposed whose main purpose is to objectively evaluate the impact and contribution of the major visualisation elements involved (henceforth mentioned as feature vectors). With this framework in mind, an online questionnaire was developed and administered to 149 test subjects in order to measure the real impact of feature vectors. The results clearly demonstrated that certain features have clear impact on user performance, and should be taken in account in LBMS development. As an example, just by displaying buildings with a 3D appearance, subjects were able to match more accurately the real environment with the one presented on a mobile device. In general, users were able to perform the tasks entrusted to them faster, if they were provided more realistic imagery.
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