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Publicações

2010

SME Managers' Most Important Entrepreneurship and Business Competences

Autores
Dominguez, C; Varajao, J; Morgado, L; Oliveira, I; Sousa, F;

Publicação
ENTERPRISE INFORMATION SYSTEMS PT II

Abstract
The requirements of an increasing globalized and competitive economy lead managers to search for training solutions which can rapidly bridge the gap of their lacking skills, knowledge or competences. To assert with adequate training programs, in particular for SMEs managers, a study was conducted in six European countries with the objective of identifying the most relevant competences they need to fulfill. A literature review and several interviews with business associations' executives resulted in a list of 34 competences which were organized in four categories: personal, team management, business and technical. These competencies were put at trial through a survey conducted among 154 SMEs managers who had to evaluate each proposed competence with the attribution of a relevance degree. Although we show that SME managers should be well prepared in a rich set of complementary areas to perform their job, it is clear that some of the competences are crucial for them to tackle today's challenges. This paper presents a ranking of the competences by importance as perceived by managers. These findings can help training institutions wishing to design new training programs which more in line with managers' needs.

2010

Identifying Clones in Functional Programs for Refactoring

Autores
Rodrigues, N; Vilaca, JL;

Publicação
ENTERPRISE INFORMATION SYSTEMS PT I

Abstract
Clone detection is well established for imperative programs. It works mostly on the statement level and therefore is ill-suited for functional programs, whose main constituents are expressions and types. In this paper we introduce clone detection for functional programs using a new intermediate program representation, dubbed Functional Control Tree. We extend clone detection to the identification of non-trivial functional program clones based on the recursion patterns from the so-called Bird-Meertens formalism.

2010

Optical refractometer based on high birefringence Bragg grating Fabry-Perot cavity

Autores
Jesus, C; Frazao, O; Jorge, PAS; Baptista, JM;

Publicação
FOURTH EUROPEAN WORKSHOP ON OPTICAL FIBRE SENSORS

Abstract
An optical fibre sensor for simultaneous measurement of refractive index and temperature is presented. The refractive index measurement is based on the visibility variations of a Fabry- Perot interferometer with interfering waves generated in a low reflectivity Bragg grating inscribed on a Panda fibre and in the fibre tip (Fresnel reflection) in contact with the liquid. The temperature measurement is based on the wavelength shift of the FBG peaks. Results obtained show the feasibility of simultaneous measurement of refractive index and temperature and also the possibility of adjusting fringe visibility via polarization control.

2010

A Metamodel-Based Approach for Automatic User Interface Generation

Autores
Rosado da Cruz, AMR; Faria, JP;

Publicação
MODEL DRIVEN ENGINEERING LANGUAGES AND SYSTEMS, PT I

Abstract
One of the advantages of following a MDA-based approach in the development of interactive applications is the possibility of generating multiple platform-specific user interfaces (UI) from the same platform independent UI model. However, the effort required to create the UI model may be significant. In the case of data-intensive applications, a large part of the UI structure and functionality is closely related with the structure and functionality of the domain entities described in the domain model, and the access rules specified in the use case model. This paper presents an approach to reduce the effort required to create platform independent UI models for data intensive applications, by automatically generating an initial UI model from domain and use case models. For that purpose, UML-aligned metamodels for domain and use case models are defined, together with a MOF-based metamodel for user interface models. The transformation rules that drive the UI model generation are introduced. It is also proposed a MDA-based process for the development of data intensive interactive applications based on the proposed model architecture and transformations.

2010

High SNR secrecy rates with OFDM signaling over fading channels

Autores
Renna, F; Laurenti, N; Poor, HV;

Publicação
IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC

Abstract
Orthogonal frequency division multiplexing (OFDM) systems have enjoyed widespread adoption in high data rate wired and wireless networks, due to their ability to efficiently cope with slowly varying dispersive channels. This paper considers the information theoretic secrecy rates that are achievable by an OFDM transmitter/receiver pair in the presence of an eavesdropper that might either use an OFDM structure or choose a more complex receiver architecture. The analysis is performed through modeling of the OFDM system with an eavesdropper as a special case of a high dimensional multiple-input multiple-output (MIMO) wiretap channel, which allows the secrecy loss due to the OFDM structure constraints, and the information gain for an eavesdropper that uses a more complex receiver to be quantified. The results are expressed in terms of both ergodic rates and outage probabilities for multipath Rayleigh fading channels, and in terms of dependence on the signal to noise ratio (SNR) ratio between the main and eavesdropper channels. ©2010 IEEE.

2010

Physical layer secrecy for OFDM systems

Autores
Renna, F; Laurenti, N; Poor, HV;

Publicação
2010 European Wireless Conference, EW 2010

Abstract
Orthogonal frequency division multiplexing (OFDM) has been established as the preferred modulation choice for highrate data transmission over dispersive channels, as it allows rejection of inter-symbol interference (ISI) and efficient utilization of the available spectrum. We address the issues of determining achievable secrecy rates and secrecy capacity for OFDM transmission in the presence of a generic eavesdropper. In doing so, we refrain from making the restrictive assumption made in previous works that the eavesdropper uses a standard fast Fourier transform (FFT)-based demodulator. First, the high SNR secrecy capacity under a total input power constraint is evaluated for both cyclic prefix and zero-padding suffix OFDM systems. It is shown that in both cases the result is sensibly lower than what we would get if the eavesdropper used an OFDM receiver. Then, optimal power allocation schemes are proposed for both types of OFDM systems and the secrecy rates are compared with results obtained by using existing power allocation methods described in the literature for parallel Gaussian wiretap channels and multiple-input multiple-output (MIMO) Gaussian wiretap channels. © 2010 IEEE.

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