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Publications

2014

Modelo de apoio à gestão da pescaria de bivalves com ganchorra no Algarve baseado em dinâmica de sistemas

Authors
Camanho, AS; Martins, JH; Oliveira, MM; Gaspar, MB;

Publication
Investigação operacional em ação: casos de aplicação

Abstract

2014

Contributo metodológico para o desenvolvimento de perfis de aplicação no contexto da Web Semântica

Authors
Malta, Mariana Curado;

Publication

Abstract
A Web Semântica (WS) é um paradigma da Web que surgiu com o intuito de ligar dados, permitindo a partilha de conteúdos para além das fronteiras das aplicações e dos sítios Web. Neste contexto, um perfil de aplicação de metadados (PA) é um constructo genérico para desenhar registos de metadados que satisfazem necessidades específicas das aplicações, proporcionando interoperabilidade semântica com outras aplicações. Esse desenho dos registos de metadados tem como base vocabulários e modelos definidos globalmente pela comunidade de metadados. A Dublin Core Metadata Initiative, provavelmente a mais conhecida e mais importante iniciativa a nível mundial no que diz respeito a metadados, definiu um modelo abstracto (Dublin Core Abstract Model) onde um dos constructos é o Dublin Core Aplication Profile (DCAP). A DCMI refere que a utilização de um DCAP é essencial para implementar interoperabilidade no contexto da WS. A concepção, o desenvolvimento e a implementação de modelos, sendo um processo complexo, necessitam de um suporte metodológico; um DCAP não foge a essa regra. Por essa razão, realizámos o estudo do estado da arte dos métodos para o desenvolvimento de PA, com o sentido de fazer o levantamento das práticas da comunidade de metadados no desenvolvimento de PA. Este estudo revelou que até à data não existe nenhum método para o desenvolvimento de um PA ou DCAP. O objectivo deste projecto de doutoramento foi o de fornecer um primeiro contributo para um tal método. A concepção do Method for the develoment of DCAP (Me4DCAP) teve como suporte: (i) as primeiras fases (até à modelação de dados) dos métodos de desenvolvimento de software; (ii) os resultados de entrevistas realizadas a desenvolvedores DCAP; (iii) as práticas identificadas no estudo já referido do estado da arte dos métodos para desenvolvimento de PA. O Me4DCAP tem como base o Singapore Framework for DCAP, e como ponto de partida o Rational Unified Process, um dos mais conhecidos e utilizados processos de desenvolvimento de software. Para realizar o nosso trabalho utilizámos a metodologia de investigação Design Science Research (DSR), no enquadramento particular para a área dos Sistemas de Informação dos três ciclos de Hevner (2007). Este enquadramento define a possibilidade da utilização de uma situação real, a que Hevner chama de “situação experimental”, para a execução de ciclos de construção-avaliação, onde o artefacto em construção - no nosso caso o Me4DCAP - vai sendo avaliado na situação experimental e redefinido, num processo iterativo. A situação experimental por nós utilizada foi o desenvolvimento de um DCAP para os Sistemas de Informação Web da comunidade mundial de Economia Social e Solidária (ESS). Esse desenvolvimento foi realizado conjuntamente com um grupo que saiu do seio da comunidade da ESS mundial. Este trabalho, identificado como uma oportunidade, resultou num DCAP-ESS. O Me4DCAP foi validado através de um grupo de discussão integrado numa conferência da especialidade, e ainda através de um Focus Group com sete especialistas mundiais de metadados. Como resultados deste doutoramento obtivemos o Me4DCAP V1.0 e o DCAP-ESS V 1.0.;The Semantic Web (SW) is a Web paradigm that emerged with the aim of linking data, enabling content share beyond the borders of Web applications and Web sites. In this context, a metadata application profile (AP) is a generic construct to design metadata records that satisfy specific needs of the applications, enabling semantic interoperability with other applications. This metadata record design is based on vocabularies and models globally defined by the metadata community. The Dublin Core Metadata Initiative (DCMI), probably the best known and most important global initiative with regard to metadata, defined an abstract model (Dublin Core Abstract Model) where one of its constructs is the Dublin Core Application Profile (DCAP). DCMI states that the use of a DCAP is very important in order to implement interoperability in the context of the SW. The conception, development and implementation of models need a methodological support since they are complex processes. Therefore, in order to understand the metadata community practices in the development of AP, we performed the study of the state of the art of the methods for the development of AP. This study revealed that until now there is no method for the development of an AP. The goal of this PhD project was to develop a first approach to such a method. The design of the Method for the development of DCAP (Me4DCAP) had as support: (i) the first stages (up to the data modeling) of software development; (ii) the results of interviews conducted to DCAP developers, (iii) the practices identified in the state of the art of the methods for AP development. Me4DCAP is based on the Singapore Framework for DCAP, and has as starting point the Rational Unified Process, one of the best known and most used software development processes. We used the research methodology Design Science Research (DSR) in our work, and the “three cycles” Information Systems specific framework defined by Hevner (2007). This framework defines the possibility of using a real situation, called by Hevner (2007) as the “experimental situation”, for the execution of the construction-evaluation cycles. In these cycles the artifact in development – in our case Me4DCAP – is being evaluated in the experimental situation, and with the feedbacks from this evaluation, it is redefined, in an iterative process. The experimental situation we used was the development of a DCAP for the Web based information systems of the Social Solidarity Economy (SSE) world community (DCAP-SSE). The DCAP-SSE development was jointly undertaken with a group from the world SSE community. This work, identified as an opportunity, resulted in a DCAP-SSE V1.0. The Me4DCAP was validated through a discussion group integrated in a metadata community international conference, and in a Focus Group with seven metadata world experts. This PhD has as results the Me4DCAP V1.0 and the DCAP-SSE V 1.0.

2014

Optimization of storage space in port grain cereal storage silos – A case study

Authors
Cardoso, MG; Ferreira, EP; Lopes, MP; Lopes, C;

Publication
Engineering Optimization IV - Proceedings of the 4th International Conference on Engineering Optimization, ENGOPT 2014

Abstract
In this paper, we present a novel mixed integer linear programming (MIP) model to solve the problem of storage space optimization in a port grain cereal silo. This work is based on a real case study for scheduling storage operations in a port cereal silo, where schedulers are faced daily with the problem of finding the best solution for transfers between storage cells, to maximize the number of empty cells, in order to have greater capacity to receive new lots, subject to storage and transportation lines capacity constraints, and receiving dispatching plans. The problem is formulated by a mixed integer linear programming model and implemented in an Excel/VBA platform. The results show that the model optimizes the number of empty cells, in computational time less than 60 seconds, and thereby constitutes a significant added value to the concerned company. © 2015 Taylor & Francis Group, London.

2014

Handgrip Strength and Nutrition Status in Hospitalized Pediatric Patients

Authors
Silva, C; Amaral, TF; Silva, D; Oliveira, BMPM; Guerra, A;

Publication
NUTRITION IN CLINICAL PRACTICE

Abstract
Background: Handgrip strength (HGS) is a useful indicator of nutrition status in adults, but evidence is lacking in pediatric patients. The aim of this study was to describe the association between undernutrition and HGS in pediatric patients at hospital admission, quantifying the modifying effect of disease severity, anthropometrics, and other patient characteristics on HGS. Materials and Methods: Eighty-nine inpatients aged >= 6 years consecutively admitted were recruited in a longitudinal study. Nutrition status was evaluated using body mass index (BMI) z scores, and HGS was evaluated at admission and discharge. Results: In the total sample, 30.3% of patients were undernourished at admission, and 64% lost HGS during the hospital stay. This study showed that HGS at admission was independently associated with undernutrition defined by BMI z scores (beta = 0.256, P = .037). In this multivariate analysis, sex, age, height, and BMI z scores explained 67.1% of HGS at hospital admission. Conclusion: Lower HGS may be a potential marker of undernutrition in hospitalized pediatric patients, although HGS data should be interpreted according to sex, age, and height of the patient.

2014

The 2nd Workshop on Planetary-Scale Distributed Systems (W-PSDS 2014)

Authors
Antunes Leitao, JC; Pereira Vilaça, RM;

Publication
33rd IEEE International Symposium on Reliable Distributed Systems Workshops, SRDS Workshops 2014, Nara, Japan, October 6-9, 2014

Abstract

2014

Impact of Feed-in Generation in Market Prices and Calibration of a Capacity Term to Pay to Traditional Generation - Application to the Iberian Market

Authors
Pereira, AJC; Saraiva, JT;

Publication
2014 11TH INTERNATIONAL CONFERENCE ON THE EUROPEAN ENERGY MARKET (EEM)

Abstract
In this paper we describe the models and the simulations that were conducted in order to access the impact of feed-in subsidized generation in the market price in Portugal in the context of the Iberian Electricity Market. In Portugal and Spain feed-in generation (namely wind power) has a large share both in terms of installed capacity and generated energy and the presence of this energy in the hourly balance originates the reduction of the market price and of the number of hours during which traditional generation (namely coal and CCGT stations) are scheduled. This paper aims at evaluating this impact both in the short term (using the real market curves) and in the long term (using a long term generation expansion planning model). The paper includes results for the Iberian power system currently having a total installed capacity above 120 GW and a total demand of 310 TWh by the end of 2013.

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