2016
Authors
Oliveira, PBD; Freire, H; Pires, EJS;
Publication
SOFT COMPUTING
Abstract
The grey wolf optimization algorithm is proposed to design proportional, integrative and derivative controllers using a two degrees of freedom control configuration. The control system is designed in order to achieve good set-point tracking and disturbance rejection performance. The design is accomplished by minimizing an aggregated cost function based on the time-weighted absolute error integral, subjected to robustness constraints. The control system robustness levels are prescribed in terms of the vector margin and maximum complementary sensitivity function values. Simulation results are presented for several common systems dynamics and compared with the ones obtained with a particle swarm optimization algorithm.
2016
Authors
Morgado, L; Almeida, A; Vilela, A; Pires, B; Cardoso, M; Paredes, H; Fonseca, B; Martins, P; Peixinho, F; Santos, A;
Publication
2016 15TH INTERNATIONAL CONFERENCE ON UBIQUITOUS COMPUTING AND COMMUNICATIONS AND 2016 INTERNATIONAL SYMPOSIUM ON CYBERSPACE AND SECURITY (IUCC-CSS)
Abstract
Learning Management Systems (LMS) provide minimal support for educational use of virtual worlds. Integration efforts assume the educators are inside the virtual world, providing hooks to services in the external LMS, to setup and manage virtual world activities. We present the inverse approach, enabling educators to setup and manage virtual world activities using the traditional LMS Web interface as an integral part of the overall educational activities of a course. In our approach, the LMS enables the teacher/trainer to setup, control, track, and store virtual world activities and its elements. It is the result of a joint effort by academic and corporate teams, implemented in the Formare LMS for OpenSimulator and Second Life Grid virtual world platforms. We explain how the Multis architecture can be used for integration, with concrete cases, an approach that can be implemented in other LMS and virtual world platforms, to overcome the limitations of existing systems for organizational management of e-learning activities.
2016
Authors
Bond, CZ; El Hadi, K; Sauvage, JF; Correia, C; Fauvarque, O; Rabaud, D; Lamb, M; Neichel, B; Fusco, T;
Publication
ADAPTIVE OPTICS SYSTEMS V
Abstract
Over the last few years the Laboratoire d'Astrophysique de Marseille (LAM) has been heavily involved in R&D for adaptive optics systems dedicated to future large telescopes, particularly in preparation for the European Extremely Large Telescope (E-ELT). Within this framework an investigation into a Pyramid wave-front sensor is underway. The Pyramid sensor is at the cutting edge of high order, high precision wave-front sensing for ground based telescopes. Investigations have demonstrated the ability to achieve a greater sensitivity than the standard Shack-Hartmann wave-front sensor whilst the implementation of a Pyramid sensor on the Large Binocular Telescope (LBT) has provided compelling operational results.1, 2 The Pyramid now forms part of the baseline for several next generation Extremely Large Telescopes (ELTs). As such its behaviour under realistic operating conditions must be further understood in order to optimise performance. At LAM a detailed investigation into the performance of the Pyramid aims to fully characterise the behaviour of this wave-front sensor in terms of linearity, sensitivity and operation. We have implemented a Pyramid sensor using a high speed OCAM2 camera (with close to 0 readout noise and a frame rate of 1.5kHz) in order to study the performance of the Pyramid within a full closed loop adaptive optics system. This investigation involves tests on all fronts, from theoretical models and numerical simulations to experimental tests under controlled laboratory conditions, with an aim to fully understand the Pyramid sensor in both modulated and non-modulated configurations. We include results demonstrating the linearity of the Pyramid signals, compare measured interaction matrices with those derived in simulation and evaluate the performance in closed loop operation. The final goal is to provide an on sky comparison between the Pyramid and a Shack-Hartmann wave-front sensor, at Observatoire de la Côte d'Azur (ONERA-ODISSEE bench). Here we present the adaptive optics setup at LAM and latest experimental and modelling results. The loop is closed on different static wave-front errors: The initial shape of the deformable mirror (DM) and a turbulent-like shape projected onto the DM. The results demonstrate a Pyramid closed loop performance of 7-8nm rms wave-front error compared to a reference at surface.
2016
Authors
Pedroso, JP; Cunha, S; Tavares, JN;
Publication
International Transactions in Operational Research
Abstract
This paper presents a class of packing problems where circles may be placed either inside or outside other circles, the whole set being packed in a rectangle. This corresponds to a practical problem of packing tubes in a container. Before being inserted in the container, tubes may be put inside other tubes in a recursive fashion. A variant of the greedy randomized adaptive search procedure is proposed for tackling this problem, and its performance is assessed in a set of benchmark instances.
2016
Authors
Adão, T; Magalhães, L; Peres, E;
Publication
SpringerBriefs in Computer Science
Abstract
This chapter presents the first stage of the procedural modelling methodology addressed in this book, which is capable of generating domus—ancient roman houses—considering rectangular constraint shapes, through the combination of an ontological schema—extended to support some elements of the roman architecture—and a treemap-based procedural modelling process, that is responsible for creating the geometry according to the rules that define the buildings. © The Author(s) 2016.
2016
Authors
Fernandes, JD; Crispim, J;
Publication
PROCEEDINGS OF THE 3RD INTERNATIONAL CONFERENCE ON PROJECT EVALUATION (ICOPEV 2016)
Abstract
This paper describes the process of formulation and validation of a synthetic risk network model for the Brazilian military shipbuilding industry. This model is composed of risk events and their potential causes that will be the basis of the process of identification and analysis of future risks on similar projects. This process involved an extensive literature review to collect and list an initial catalogue of risks, causes and related effects, followed by an analysis to summarise and schematically group the risks. Then, the Delphi method with a panel of experts from the Brazilian Navy was used to analyse and assess the proposed model.
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