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Publications

2015

A Pitch-Depth Bottom Following Controller for AUVs using Eigenstructure Assignment

Authors
Melo, J; Matos, A;

Publication
IFAC PAPERSONLINE

Abstract
This paper addresses the problem of bottom following by the MARES Autonomous Underwater Vehicle, and presents derivation of a controller able to cope with the peculiarities of such problem. In specific, the main requirement for the controller is the existence of no overshoot both in the depth and pitch outputs of the system. The existence of such time-domain requirements motivates the use of Eigenstructure Assignment techniques in the formulation of the controller. Simulation results obtained with a dynamic model of the MARES AUV are presented and discussed, indicating the validity of the proposed approach.

2015

Are Rankings of Financial Analysts Useful to Investors?

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

Publication
SSRN Electronic Journal

Abstract

2015

Relationship Between Game Categories and Skills Development: Contributions for Serious Game Design

Authors
Baptista, R; Coelho, A; de Carvalho, CV;

Publication
PROCEEDINGS OF THE 9TH EUROPEAN CONFERENCE ON GAMES BASED LEARNING (ECGBL 2015)

Abstract
Recently, Serious Games (SG) achieved a recognized position as a learning tool in several contexts. SG provide constructive learning environments in which errors can be made without real life penalties and where students get instant feedback from their actions when facing challenges. These challenges should be in accordance with the intended learning goals and they should adapt and/or be repeated according to the learner's level. This aspect is decisive in the acquisition of knowledge, experience and professional skills through the simulation of different situations and contexts. The effectiveness of competences' training is directly related to the success in their acquisition but, above all, it is related to the ability to apply them to successfully perform a given task. However, an optimal game design methodology for competence training is yet to be created. This article presents a study that identifies the most appropriate game categories to develop specific skills and competences. It considers a taxonomy with eight game categories (Action, Strategy, Playing, Sports, Management Simulation, Adventure, Puzzle and Quiz) that were matched with the Education Competences and Educational Competency Wheel. Analysing 116 serious games allowed identifying which categories were more efficient in the training of a specific competence and therefore should be reused in the same scope.

2015

Simultaneous measurement of strain and temperature based on clover microstructured fiber loop mirror

Authors
Perez Herrera, RA; Andre, RM; Silva, SF; Becker, M; Schuster, K; Kobelke, J; Lopez Amo, M; Santos, JL; Frazao, O;

Publication
MEASUREMENT

Abstract
In this work, two all-fiber loop mirrors using a clover microstructured fiber for the simultaneous measurement of temperature and strain are presented. The sensing heads are formed by a short piece of clover microstructured fiber with 35 mm and 89 mm length respectively. The geometry of the fiber allowed observing different interferences created by the microstructured fiber core section. Different sensitivities to temperature and strain were obtained and, using a matrix method, it is possible to discriminate both physical parameters. Resolutions of +/- 2 degrees C and +/- 11 mu epsilon for the first structure and +/- 2.3 degrees C and +/- 18 mu epsilon for the second one, for temperature and strain, respectively, were attained.

2015

ANALYSIS OF SOURCES OF RISK AND UNCERTAINTIES IN THE ELECTRICITY SYSTEM

Authors
Santos, MJ; Ferreira, P; Araujo, M;

Publication
PROCEEDINGS OF THE 2ND INTERNATIONAL CONFERENCE ON ENERGY & ENVIRONMENT: BRINGING TOGETHER ENGINEERING AND ECONOMICS

Abstract
Electricity power planning is a serious national task that encompasses not only forecasts but more importantly the evolution in short, medium and long term of each element that composes the assumptions, the constraints and/or the parameters of the planning model. Deterministic models can bring simplicity to the electricity power planning but do not consider the uncertainties and sources of risk of the electricity system. On the other hand, stochastic models tend to include the behavior of one or more uncertain parameters that are critical to obtain a robust solution, being however more detailed and lengthy than deteministic models. The aim of this work was to identify the major sources of risk and uncertainties facing electricity system, representing valuable input for the electricit planner task. From this study it can be observed that several different behaviours for each uncertain parameter can be found along a time horizon. Thus, it is concluded that reling on average lowers can represent a reductionist approach and in order to obtain more reliable scenarios for future electricity system, the statistical charcateristics of each parameter should be considered in the electricity power planning.

2015

Selection constructive based hyper-heuristic for dynamic scheduling

Authors
Gomes, S; Madureira, A; Cunha, B;

Publication
2015 10th Iberian Conference on Information Systems and Technologies, CISTI 2015

Abstract
Manufacturing environments require a real-time adaptation and optimization method to dynamically and intelligently maintain the current scheduling plan feasible. This way, the organization keeps clients satisfied and achieves its objectives (costs are minimized and profits maximized). This paper proposes an optimization approach - Selection Constructive based Hyper-heuristic for Dynamic Scheduling - to deal with these dynamic events, with the main goal of maintaining the current scheduling plan feasible and robust as possible. The development of this dynamic adaptation approach is inspired on evolutionary computation and hyper-heuristics. Our empirical results show that a selection constructive hyper-heuristic could be advantageous on solving dynamic adaptation optimization problems. © 2015 AISTI.

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