2015
Autores
Esteves, MS; Azevedo Perdicoulis, TPA; dos Santos, PL;
Publicação
CONTROLO'2014 - PROCEEDINGS OF THE 11TH PORTUGUESE CONFERENCE ON AUTOMATIC CONTROL
Abstract
System Identification (SI) is a methodology for building mathematical models of dynamic systems from experimental data, i.e., using measurements of the system input/output (IO) signals to estimate the values of adjustable parameters in a given model structure. The process of SI requires some steps, such as measurement of the IO signals of the system in time or frequency domain, selection of a candidate model structure, choice and application of a method to estimate the value of the adjustable parameters in the candidate model structure, validation and evaluation of the estimated model to see if the model is right for the application needs, which should be done preferably with a different set of data, [PS] and [Lj1]. © 2015 Springer International Publishing.
2015
Autores
Lazecky, M; Perissin, D; Bakon, M; de Sousa, JM; Hlavacova, I; Real, N;
Publicação
2015 JOINT URBAN REMOTE SENSING EVENT (JURSE)
Abstract
Satellite SAR interferometry (InSAR) is proven as effective method for monitoring of deformations of both terrain and urban structures. By applying multi-temporal InSAR processing techniques (for example Persistent Scatterers InSAR-PS InSAR) to a series of radar images over the same region, it is possible to detect both vertical and horizontal movements of such structures and to evaluate rate of their movements in sensitivity of first millimeters in direction of satellite sight (usually inclined by 20-35 degrees from vertical axis). Therefore, it is possible to identify abnormal or excessive movement indicating potential problems requiring detailed ground investigation. Three case studies (in Bratislava, Ostrava and Hong Kong) presented within the paper demonstrate potential for monitoring deformations and movements due to thermal dilation of bridge structures.
2015
Autores
Teixeira A.A.C.;
Publicação
Corruption Economic Growth and Globalization
Abstract
2015
Autores
de Moura Oliveira, PBD; Mendes, C; Iria, L; Solteiro Pires, EJS; Boaventura Cunha, JB;
Publicação
IFAC PAPERSONLINE
Abstract
The refinement of an existing internet multimedia tool to support teaching/learning activities concerning GRAFCET is reported here. The tool called c-GRAFCET resulted in an updated and improved version called e-GRAFCET+. The overall objective of this internet-based tool is to provide fundamental aspects regarding GRAFCET presented with animated examples, promoting students self-learning. While originally this tool was developed to be used by Portuguese speakers, now it is also available in English. The tool upgrading resulted in the elaboration of a new internet portal, incorporating new features, concerning the site management and question quizzes updating. A very important feature of e-GRACFCET+, is to be prepared to work on most devices regardless of operating systems and screen sins, such as smart-phones and tablets.
2015
Autores
Teixeira, F; Santos, J; Pessoa, LM; Pereira, M; Campos, R; Ricardo, M;
Publicação
WUWNet
Abstract
Radio Frequency (RF) communications su.er high attenuation underwater, limiting the range of standard IEEE 802.11 networks to a few centimeters underwater. The usage of custom RF solutions at lower frequencies to increase range entails high development costs, and proprietary hardware. This paper evaluates the performance of cost-e.ective, mass-market IEEE 802.11 networks underwater at di.erent frequencies in the sub-GHz bands using Software Defined Radio platforms. Optimizations to the gr-ieee802.11 implementation, together with custom designed antennas, allowed the testing of frequencies in the 70-700 MHz range, in a large-scale freshwater tank, and in real-world, seawater conditions in Tagus river estuary. Results show a frequency-dependent communications range up to 5 m in freshwater and 1.8 m in seawater, with bitrates up to 550 kbit/s and delay under 45 ms. This proves the feasibility of IEEE 802.11 networks in the sub-GHz bands for applications such as video streaming from an autonomous underwater vehicle and underwater sensors.
2015
Autores
Gomes, S; Madureira, A; Cunha, B;
Publicação
2015 10TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI)
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.
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