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Publicações

2009

A study on the determination of stochastic reinforcement permeability in constant injection pressure conditions

Autores
Gonçalves, PCT; Correia, NC;

Publicação
ICCM International Conferences on Composite Materials

Abstract
We report two effects in permeability measurement: the error introduced by assuming constant injection pressure and the evolution of permeability dispersion with volume fraction. For the first, we proposed a simple modelling approach. For the second, our results showed a reduction in the dispersion with higher fibre volume fractions, which we believe is due to the reduction of the variability of the size of the pores of the reinforcement.

2009

A Hybrid Genetic-Heuristic Algorithm for Scheduling of Automated Guided Vehicles and Quay Cranes in Automated Container Terminals

Autores
Homayouni, SM; Tang, SH; Ismail, N; Ariffin, MKAM; Samin, R;

Publicação
CIE: 2009 INTERNATIONAL CONFERENCE ON COMPUTERS AND INDUSTRIAL ENGINEERING, VOLS 1-3

Abstract
Containers have been used in past decades increasingly as one of the most important transportation tools. Containers have revolutionized cargo shipping and thus changed the world trade systematically. Container terminals as the transhipment facility play a valuable role in performance of this transportation system. Improvement of this facility has been widely considered in literatures. Automated container terminals (ACTs) have been introduced to pursue this purpose. In ACTs various transport vehicles are automated and integrated to each other. Automated guided vehicles (AGVs) are used in ACTs to handle containers between quay cranes and storage yards. Usually scheduling of the AGVs is known as the key factor to improve the performance of ACTs. This paper proposed a heuristic algorithm to schedule the AGVs concurrently with quay cranes. A genetic algorithm is proposed to optimize the simultaneous scheduling of AGVs and QCs. The results showed that proposed genetic algorithm can be used in practical implications while its running time is reasonably low.

2009

Wikis4SE 2009: wikis for software engineering

Autores
Aguiar, A; Flores, N; Merson, P;

Publicação
Proceedings of the 2009 International Symposium on Wikis, 2009, Orlando, Florida, USA, October 25-27, 2009

Abstract
Due to the simplicity, attractiveness and effectiveness for collaborative authoring and knowledge management, wikis are now massively disseminated and used in different domains. This workshop focuses on wikis for the specific domain of software engineering. It aims at bringing together researchers, practitioners, and enthusiasts interested on researching, exploring and learning how wikis can be improved, customized and used to better support software engineering. Based on lessons learned and obstacles identified, a research agenda will be defined with key opportunities and challenges. This edition at WikiSym'2009 follows others at ICSE'2009, WikiSym'2008 and WikiSym'2007. Copyright © 2009 ACM.

2009

Commitment and Authentication Systems

Autores
Pinto, A; Souto, A; Matos, A; Antunes, L;

Publicação
INFORMATION THEORETIC SECURITY

Abstract
In the present paper, we answer a question raised in the paper Constructions and Bounds for Unconditionally Secure Non-Interactive Commitment Schemes, by Blundo et al, 2002, showing that there is a close relation between unconditionally secure commitment schemes and unconditionally secure authentication schemes, and that an unconditionally secure commitment scheme can be built from such an authentication scheme and an unconditionally secure cipher system. To investigate the opposite direction, we define optimal commitment systems and show that these must be resolvable design commitment schemes. Then, a proof is given that the resolvable design commitment schemes are a composition of an authentication system and a cipher system and the conclusion follows that this is the case for all optimal commitment systems. We also show how to build optimal schemes from transversal designs that are easy to build and can be more efficiently implemented than the proposal in the previously cited paper.

2009

Hybrid sol-gel planar optics for astronomy

Autores
Ghasempour, A; Leite, AMP; Reynaud, F; Marques, PVS; Garcia, PJV; Alexandre, D; Moreira, PJ;

Publicação
OPTICS EXPRESS

Abstract
Hybrid sol-gel planar optics devices for astronomy are produced for the first time. This material system can operate from the visible (0.5 mu m) up to the edge of astronomical J-band (1.4 mu m). The design, fabrication and characterization results of a coaxial three beam combiner are given as an example. Fringe contrasts above 94% are obtained with a source with spectral bandwidth of 50 nm. These results demonstrate that hybrid sol-gel technology can produce devices with high quality, opening the possibility of rapid prototyping of new designs and concepts for astronomical applications. (C) 2009 Optical Society of America

2009

Change Detection in Climate Data over the Iberian Peninsula

Autores
Sebastiao, R; Rodrigues, PP; Gama, J;

Publicação
2009 IEEE INTERNATIONAL CONFERENCE ON DATA MINING WORKSHOPS (ICDMW 2009)

Abstract
This paper addresses the space-time change detection problem in climate data over the Iberian Peninsula using a 50 years dataset. The data were analyzed concerning the temporal and geographical information, using the following methodology: information about space-time drifts in climate data was obtained by applying a change detection algorithm on all the temporal data available for each physical location considered in this study; the performance and the robustness of this algorithm were then assessed by the McNemar nonparametric statistical test on cluster structures; geographical correlations were inferred using visualization tools and graphical representations of data. Most of the space-temporal drifts detected by the algorithm were confirmed by the results of the McNemar test and are in accordance with visual and graphical representations, supporting the advantage of using inter-disciplinary methods. This analysis also shows that there are locations which do not reveal any change along all the observed years.

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