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- Ambiguidade e consequências futuras dos comportamentos éticos: estudo interculturalPublication . Ferreira, Manuel Portugal; Pinto, Cláudia Frias; Santos, João Carvalho; Serra, Fernando A. RibeiroOs comportamentos de ética empresarial têm sido questionados, com os recentes escândalos económico-financeiros e as práticas de empresas e trabalhadores. Neste estudo, baseado em dados recolhidos por questionário, comparamos as perceções de ética de estudantes portugueses (N=109) e brasileiros (N=190) de Administração, expostos a um conjunto de cenários de ética e aceitabilidade de práticas comerciais, diante de duas dimensões culturais: a tolerância à ambiguidade e a antecipação das consequências futuras. Os resultados mostram diferenças significativas entre os brasileiros e os portugueses nas três dimensões, sendo os brasileiros mais tolerantes à ambiguidade e mais conscientes das consequências futuras dos seus atos, mas com maior propensão a comportamentos menos éticos. A perspetiva de ganhos mais imediatos parece sobrepor-se à incerteza e aos riscos a médio e longo prazos que a prática de comportamentos menos éticos pode acarretar. Concluímos com uma discussão ampla e pistas para investigação futura.
- Data warehousing in the context of a Bologna undergraduate degreePublication . Ramos, José Vitor; Rui OliveiraFacing the incessant growth of data that organizations have to deal with on a daily basis, decision support systems and data warehousing techniques assume a vital importance in supporting the decision making process. Taking this necessity in consideration, the Bologna process was an opportunity to introduce data warehousing competences in the undergraduate degree of Informatics Engineering at Polytechnic Institute of Leiria (IPL). The paper focus some aspects related with this adaptation, the difficulties and challenges during the implementation process and the solutions adopted, towards an effective acquisition of competences by students.
- Coding Tree Depth Estimation for Complexity Reduction of HEVCPublication . Correa, G.; Assunção, P.; Agostini, L.; Cruz, L. A. D. S.The emerging HEVC standard introduces a number of tools which increase compression efficiency in comparison to its predecessors at the cost of greater computational complexity. This paper proposes a complexity control method for HEVC encoders based on dynamic adjustment of the newly proposed coding tree structures. The method improves a previous solution by adopting a strategy that takes into consideration both spatial and temporal correlation in order to decide the maximum coding tree depth allowed for each coding tree block. Complexity control capability is increased in comparison to a previous work, while compression losses are decreased by 70%. Experimental results show that the encoder computational complexity can be downscaled to 60% with an average bit rate increase around 1.3% and a PSNR decrease under 0.07 dB.
- A new diagnostic technique for real-time diagnosis of power converter faults in switched reluctance motor drivesPublication . Marques, Jorge F.; Estima, Jorge O.; Gameiro, Natália S.; Cardoso, A. J. MarquesAccurate fault identification allows the adoption of procedures that minimize the fault impact on the machines operation. Switched reluctance motors (SRMs) have been recognized for their fault-tolerant capabilities and they present a very robust configuration, particularly due to the absence of windings or magnets in the rotor. All these attributes make the SRM a competitive solution for aircraft and automotive applications, where systems reliability is a crucial feature. Therefore, in this paper, a new algorithm for real-time diagnosis of power converter faults in SRM drives is proposed. In contrast to other methods that use additional sensors or devices, the presented technique uses the measured phase currents only, which are already available for the drive control. The proposed algorithm effectively detects the inverter faulty phase and is capable to localize the faulty power switch. Power switch open-and short-circuit fault occurrences in an asymmetric full-bridge converter are considered and analyzed.
- Loss and reliability optimization for power distribution system operationPublication . Vitorino, R.M.; Jorge, H.M.; Neves, L.P.This study presents an optimization method that combines simultaneously the reliability and the efficiency of radial power distribution systems (RDS), minimizing active energy losses, through a process of network reconfiguration. The study is based on the failure analysis on network branches, with a special concern regarding the protection system response to faults and the service restoration procedures, during the emergency state. A non-sequential Monte Carlo simulation based on the branch reliability was used to evaluate reliability of the network configurations. Due to a large number of possible configurations and the need of an efficient search, the optimization is made through an improved genetic algorithm (IGA). The method analyses the RDS considering in a first step, the absence of investment, and in a second step, the possibility of placing a limited number of new tie-switches in certain branches, according to the definitions made by a decision maker. The effectiveness of the proposed methodology is demonstrated through the analysis of a 69 bus RDS and by comparison against other reported methodologies.
- EditorialPublication . Bártolo, Paulo; Chua, C.K.This is the first issue of Virtual and Physical Prototyping in 2013. The first three papers of this issue were selected from 2012 International Additive Manufacturing Forum held in Wuhan, China, from 13 to 16 December. The primary purpose of this conference was to review the latest state and trend of Additive Manufacturing technologies. This conference was dedicated to AM research. Through this conference, new findings on the AM processes and potential technical applications in major industries were shared and made available to participants. It was intended that this valuable information be made available to the AM research community to encourage further technological advancements in this field through this special issue.
- Damage assessment on concrete surfaces using multi-spectral image analysisPublication . Valença, J.; Gonçalves, Luísa M.S.; Júlio, E.To monitor the state of conservation of structures is extremely important to plan maintenance interventions, thus allowing minimizing associated costs. The aim of this paper is to investigate if Very High Spatial Resolution (VHSR) multispectral images can be used to detect, analyse and measure areas with biological colonization, stains and/or repair materials on exposed concrete surfaces. With this aim, the authors present a method, SurfCrete – Multi-spectral image analysis of concrete surfaces, which was tested to classify surface images of exposed concrete buildings where biological colonization, exposed aggregates, repairing mortars and cracks were previously detected on a visual inspection. This technique was performed using four multi-spectral bands (blue, green, red and near infrared). A vegetation index was also considered, as additional band information, to evaluate its usefulness in this kind of applications. SurfCrete allowed to achieve a global classification accuracy of 94%, which indicates that the identification of different materials, as well as damage, can be obtained from VHSR multispectral images using the developed methodology with a high accuracy. Surface mapping and statistical results are automatically obtained and stored in digital format which can be valuable when applied to large exposed concrete areas. Furthermore, results demonstrate that most accurate outputs can be derived using the near infrared band.
- Estudo experimental da ventilação e do comportamento térmico de uma cobertura em telha cerâmica com beiral ventilado e sub-telhaPublication . Almeida, Luís Pedro Rodrigues; Ramos, João António EstevesOs métodos tradicionais utilizados na construção, envolvendo soluções não sustentáveis e novos regulamentos na área do desempenho térmico e ambiental dos edifícios, têm vindo a aumentar o desenvolvimento de novos projectos com incorporação de tecnologias passivas. Este estudo foi concebido para estudar o impacto da ventilação natural gerado entre o lado interior da telha cerâmica e os canais da sub-telha ondulada para coberturas com beiral ventilado, assim como a análise do seu desempenho térmico através da avaliação das transferências de calor na telha cerâmica e também na caixa-de-ar. Foi construída uma célula de teste e testada sob as condições exteriores para se obter dados de temperatura a partir do desvão e do telhado, de modo a comparar o fluxo de calor, em regime transiente. Observando os resultados, conclui-se que a utilização de telhado ventilado reduz as transferências de calor entre as camadas da cobertura. Os resultados experimentais indicaram que o número de Reynolds é inferior a 1800 e a velocidade média do ar foi de 0,2 m/s. Estes resultados comprovam que o fluxo de ar de ventilação natural é laminar, principalmente durante condições quentes de verão com elevada radiação solar.
- Impacto das características do portal e dos consumidores online na satisfação, confiança e lealdade à marca Booking.comPublication . Cruz, Raquel SilvaAs relações “cliente - fornecedor” são cada vez mais valiosas e menos consistentes, sobretudo no contexto online. Assim, o fornecedor procura tornar um visitante do website num cliente satisfeito e um cliente satisfeito num cliente leal, como condição para se tornar mais competitivo. Compreender o que determina a lealdade de um cliente online e o papel da satisfação e da confiança nessa relação é o principal objetivo desta investigação. Assim, com base na informação recolhida através de questionário numa amostra de 104 clientes do portal Booking.com, efetuou-se o estudo quantitativo, transversal e de natureza exploratória, com a finalidade de estudar a relação entre as variáveis: características do portal, personalidade dos consumidores online, e-satisfação, e-confiança e a lealdade à marca Booking.com Os resultados evidenciaram que a personalidade dos clientes do portal Booking.com tem capacidade para explicar a sua confiança e lealdade, enquanto as características do website têm capacidade para explicar a e-satisfação, sendo esta um determinante da e-confiança e da e-lealdade dos clientes à marca Booking.com. Tendo em conta estes resultados, no final do presente estudo, serão apresentadas as contribuições do mesmo e recomendações direcionadas aos gestores de websites e de marcas no âmbito eletrónico.
- Refletindo sobre a Prática Pedagógica em Educação de Infância e em 1.º Ciclo do Ensino Básico “Descobrindo as formigas” – uma proposta pedagógica em jardim de infânciaPublication . Duarte, Raquel Dias; Reis, Susana Alexandre dos; Saraiva, Alzira Maria Rascão