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Publications

2007

Quantitative evaluation of Clusterings for marketing applications: A web portal case study

Authors
Rebelo, C; Brito, PQ; Soares, C; Jorge, A; Brandao, R;

Publication
PROGRESS IN ARTIFICIAL INTELLIGENCE, PROCEEDINGS

Abstract
The potential value of a market segmentation for a company is usually assessed in terms of six criteria: identifiability, substantiality, accessibility, responsiveness, stability and actionability. These are widely accepted as essential criteria, but they are difficult to quantify. Quantification is particularly important in early stages of the segmentation process, especially when automatic clustering methods are employed. With such methods it is easy to produce a large number of segmentations but only the most interesting ones should be selected for further analysis. In this paper, we address the problem of how to quantify the value of a segmentation according to the criteria above. We propose several measures and test them on a case study, consisting of a segmentation of portal users.

2007

icBench - A benchmarking tool for Portuguese construction industry companies

Authors
da Costa, JM; Horta, I; Guimaraes, N; Novoa, H; Cunha, JF; Sousa, R;

Publication
International Journal for Housing Science and Its Applications

Abstract
The icBench Project (Construction Industry Benchmarks) has developed a web-based flexible platform to quickly evaluate a company's performance through a set of pre-defined indicators. The Information and Communication Technology (ICT) platform is built to support this set of indicators, although its architecture has been defined so that changes or adjustments to other industries can be easily implemented. The platform is also designed to provide two types of functionalities. One is to act as an internal data management system for each user company. The other is to allow for external benchmarking comparisons. The icBench project aims at being a straightforward tool for providing guidance to construction companies, ensuring that businesses are identifying and targeting the right problems and aware of best practices. Starting with a pre-defined selection of 50 contractors, 50 consultants and 50 construction materials companies, the project expects to expand its usage amongst all construction companies after wider dissemination of the project's results planned for later this year. Copyright © 2007 IAHS.

2007

Fabrication and test of an integrated optical sensor with high sensitivity and high dynamic range based on a Mach-Zehnder interferometric configuration

Authors
Alexandre, D; Viegas, J; Fernandes, L; Moreira, PJ; Leite, AMP; Santos, JL; Marques, PVS;

Publication
Optical Sensing Technology and Applications

Abstract
Integrated optics (IO) technology has been primarily used in optical communication applications but it is expanding fast into the field of optical sensing. In this work we report the fabrication of integrated devices using hybrid sol-gel technology and in particular its application in the fabrication of a refractive index integrated sensor based in a Mach-Zehnder interferometric configuration. In one of the interferometer arms, a analysis chamber is created by exposing the waveguide through the removal of the device cladding. On the same arm, two Bragg gratings with the same period are fabricated: one in the unprotected waveguide area and another in close proximity (cladded area); because of the different effective index in the two grating regions, two peaks are observed in reflection if the device is tested with a broadband source. Any change of the refractive index of the material filling the analysis chamber can be detected in two ways: by measuring the intensity of the interferometric output (at a wavelength different from the Bragg wavelength of the two gratings) or by measuring the spectrum of the reflected signal. The high sensitivity is obtained by measuring the interferometric output, while the high dynamic range can be achieved by measuring the reflected signal from the grating structures.

2007

Decision under risk as a multicriteria problem

Authors
Matos, MA;

Publication
EUROPEAN JOURNAL OF OPERATIONAL RESEARCH

Abstract
Most of the approaches to decision problems under uncertainty are based on decision paradigms, generally associated to an optimization process that leads to a final solution. For the Decision Maker, the basic decision is thus what paradigm to choose, the rest of the procedure being mainly technical. In this paper, a different approach is advocated for this kind of problems. The main idea is to leave prescriptive models in favor of a more flexible approach, where risk related criteria are explicitly considered, conducting to an '' equivalent '' multicriteria (deterministic) model where decision-aid procedures can be used, with a greater involvement of the Decision Maker. The paper discusses first the uncertainty model and then reviews existing paradigms for the single criterion problem under uncertainty. Proposed risk and opportunity attributes come mainly from the analysis of those methodologies and from risk perception studies reports. Some hints about multicriteria aid methods and an illustrative example complete the paper.

2007

The evolution and the future of the e-Gov [A evolução e o futuro do governo electrónico]

Authors
Campos, R; Marques, CG;

Publication
Euro American Conference on Telematics and Information Systems - Proceedings of the 2007 Euro American Conference on Telematics and Information Systems, EATIS 2007

Abstract
After a continuously development in on-line availability, most of the countries are close to reach the highest point of public services maturity. The future of e-Gov should now go through accessibility questions and m-Gov, providing a new set of user-centred services, personalized and based on alerts that could be programmed taking into account knowledge based in the localization of the user. In this article we will analyze the stage of e-Gov in Europe based in a report of the European Commission, which allows, the realization of a comparative analysis of the evolution occurred between 2004 and 2006 in the 28 countries part of the study. Following, we analyze the case of Portugal, pointing out some of the reasons to the success of the measures applied. Finally we project the future of e-Gov in terms of accessibility questions, platform access independence and user-centred services.

2007

Hausdorff dimension bounds for smoothness of holonomies for codimension 1 hyperbolic dynamics

Authors
Pinto, AA; Rand, DA; Ferreira, E;

Publication
JOURNAL OF DIFFERENTIAL EQUATIONS

Abstract
We prove that the stable holonomies of a proper codimension 1 attractor Lambda, for a C-r diffeomorphism f of a surface, are not C1+theta for theta greater than the Hausdorff dimension of the stable leaves of f intersected with Lambda. To prove this result we show that there are no diffeomorphisms of surfaces, with a proper codimension 1 attractor, that are affine on a neighbourhood of the attractor and have affine stable holonomies on the attractor.

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