Browsing by Issue Date, starting with "2009-08"
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- Patient safety as a radiotherapy department: how can we enhance safety?Publication . Eiras, Margarida; Diegues, I.; Grillo, I. Monteiro; Escoval, AnaPurpose: Medical errors can be classified into five categories: poor decision making, poor communication, inadequate patient monitoring, patient misidentification, inability to respond rapidly, and poor patient tracking. Employing innovative information technologies in correcting these deficiencies is the current trend in enhancing patient safety. Radiofrequency (RF) identification is one technology that has significant potential to secure the medical supply chain and increase the safety and efficiency of healthcare processes. It is our purpose to identify patient waiting times; identify treatment unit occupation and guarantee patient and its accessories’ identification.
- A cultura, os valores contabilísticos e o julgamento profissional dos preparadores e dos revisores/auditores portuguesesPublication . Albuquerque, Fábio; Almeida, Maria do CéuA teoria da relevância cultural da Contabilidade proposta por Gray (1988) destaca a ligação dos valores contabilísticos com as práticas que se materializam na forma, conteúdo e características qualitativas apresentadas no relato financeiro. Mais recentemente, a nova Estrutura Conceptual, em fase de elaboração conjunta pelo FASB e pelo IASB, representa um capítulo de significativo interesse no contexto de aprofundamento do movimento de harmonização contabilística internacional. Esta dissertação analisa a classificação atribuída por Gray (1988) a Portugal, com base nos valores contabilísticos identificados para os preparadores e revisores/auditores da informação financeira. Este trabalho passa ainda por analisar o julgamento destes profissionais relativamente à importância e entendimento dos conceitos relacionados com as características qualitativas e os constrangimentos à informação, tal como submetidos à discussão pública no âmbito do projecto da nova Estrutura Conceptual. Os dados foram recolhidos a partir de um questionário conduzido a uma amostra de 80 Técnicos Oficiais de Contas e 80 Revisores Oficiais de Contas, posteriormente submetidos a testes não-paramétricos e a técnicas de análise multivariada. Os resultados encontraram um forte apoio para o valor contabilístico do controlo estatutário, um razoável apoio para a uniformidade e o conservadorismo e um fraco apoio para o secretismo, sugerindo uma reclassificação do país ou a redefinição de tais valores. Por outro lado, embora tenham sido encontradas diferenças significativas entre os preparadores e os revisores/auditores relativamente à importância dos conceitos relacionados com as características qualitativas e os constrangimentos à informação, não foram encontradas diferenças significativas relativamente ao entendimento de tais conceitos por parte dos referidos profissionais. Pretende-se que esta dissertação e posteriores desenvolvimentos deste estudo ajudem a considerar a importância dos aspectos subjectivos relacionados com a qualidade da informação no processo de relato financeiro.
- Robustness assessment of model-based control for the archimedes wave swingPublication . Valério, Duarte; Beirão, Pedro; Mendes, Mário J. G. C.; Costa, José Sá daIn this paper the robustness of three model-based control strategies—internal model control (IMC) with linear models, IMC with neural network models, and feedback linearisation control—for the Archimedes Wave Swing (AWS), a device designed to produce electricity from the energy of sea waves, is assessed by checking how their performance, optimised for a neutral tide with a standard atmospheric pressure, changes under high and low tides, and under atmospheric pressure variations. The original AWS controller and latching control are used as a term of comparison. Simulation results show that, as a rule, low tides and lower atmospheric pressures lead to higher power productions, while high tides and higher atmospheric pressures lead to lower power productions; but, in spite of model maladjustments, model-based control strategies are not at disadvantage when compared with latching control.
- MDAI: Model based design in automobile industryPublication . Ferreira, JoaoIt is proposed a new approach based on a methodology, assisted by a tool, to create new products in the automobile industry based on previous defined processes and experiences inspired on a set of best practices or principles: it is based on high-level models or specifications; it is component-based architecture centric; it is based on generative programming techniques. This approach follows in essence the MDA (Model Driven Architecture) philosophy with some specific characteristics. We propose a repository that keeps related information, such as models, applications, design information, generated artifacts and even information concerning the development process itself (e.g., generation steps, tests and integration milestones). Generically, this methodology receives the users' requirements to a new product (e.g., functional, non-functional, product specification) as its main inputs and produces a set of artifacts (e.g., design parts, process validation output) as its main output, that will be integrated in the engineer design tool (e.g. CAD system) facilitating the work.
- Die surface designer systemPublication . Ferreira, JoaoThis paper defines Die Surface Designer (DSD) System for fast draw die in the product development feasibility phase on surfaces coming from styling. We propose a CAD integration, for better support the design process in industry, particularly on the development of new products in automotive sector. The DSD system intends to reduce the lead time by providing and integrating flexible and efficient capabilities for testing early concepts from surface analysis points of view in automotive product development.
- Low complexity intra mode selection for efficient distributed video codingPublication . Ascenso, Joao; Pereira, FernandoMotion compensated frame interpolation (MCFI) is one of the most efficient solutions to generate side information (SI) in the context of distributed video coding. However, it creates SI with rather significant motion compensated errors for some frame regions while rather small for some other regions depending on the video content. In this paper, a low complexity Infra mode selection algorithm is proposed to select the most 'critical' blocks in the WZ frame and help the decoder with some reliable data for those blocks. For each block, the novel coding mode selection algorithm estimates the encoding rate for the Intra based and WZ coding modes and determines the best coding mode while maintaining a low encoder complexity. The proposed solution is evaluated in terms of rate-distortion performance with improvements up to 1.2 dB regarding a WZ coding mode only solution.
- Limiting internal supply voltage spikes in DC-DC convertersPublication . Rocha, José; Santos, Marcelino; Monteiro, Ângelo; Neves, Alexandre; Braga, PedroImplementing monolithic DC-DC converters for low power portable applications with a standard low voltage CMOS technology leads to lower production costs and higher reliability. Moreover, it allows miniaturization by the integration of two units in the same die: the power management unit that regulates the supply voltage for the second unit, a dedicated signal processor, that performs the functions required. This paper presents original techniques that limit spikes in the internal supply voltage on a monolithic DC-DC converter, extending the use of the same technology for both units. These spikes are mainly caused by fast current variations in the path connecting the external power supply to the internal pads of the converter power block. This path includes two parasitic inductances inbuilt in bond wires and in package pins. Although these parasitic inductances present relative low values when compared with the typical external inductances of DC-DC converters, their effects can not be neglected when switching high currents at high switching frequency. The associated overvoltage frequently causes destruction, reliability problems and/or control malfunction. Different spike reduction techniques are presented and compared. The proposed techniques were used in the design of the gate driver of a DC-DC converter included in a power management unit implemented in a standard 0.35 mu m CMOS technology.
- Criticality of colloids with distinct interaction patches: The limits of linear chains, hyperbranched polymers, and dimersPublication . Tavares, Jose; Teixeira, Paulo; Gama, MargaridaWe use a simple model of associating fluids which consists of spherical particles having a hard-core repulsion, complemented by three short-ranged attractive sites on the surface (sticky spots). Two of the spots are of type A and one is of type B; the bonding interactions between each pair of spots have strengths epsilon(AA), epsilon(BB), and epsilon(AB). The theory is applied over the whole range of bonding strengths and the results are interpreted in terms of the equilibrium cluster structures of the phases. In addition to our numerical results, we derive asymptotic expansions for the free energy in the limits for which there is no liquid-vapor critical point: linear chains (epsilon(AA)not equal 0, epsilon(AB)=epsilon(BB)=0), hyperbranched polymers (epsilon(AB)not equal 0, epsilon(AA)=epsilon(BB)=0), and dimers (epsilon(BB)not equal 0, epsilon(AA)=epsilon(AB)=0). These expansions also allow us to calculate the structure of the critical fluid by perturbing around the above limits, yielding three different types of condensation: of linear chains (AA clusters connected by a few AB or BB bonds); of hyperbranched polymers (AB clusters connected by AA bonds); or of dimers (BB clusters connected by AA bonds). Interestingly, there is no critical point when epsilon(AA) vanishes despite the fact that AA bonds alone cannot drive condensation.