Comparative analysis of the ground reaction forces, during the support phase, in a group of pregnant women on their 3rd trimester of pregnancy and in a group of not pregnant women

PURPOSE: To analyze and compare the Ground Reaction Forces (GRF), during the stance phase of walking in pregnant women in the 3rd trimester of pregnancy, and non pregnant women. METHODS: 20 women, 10 pregnant and 10 non pregnant, voluntarily took part in this study. GRF were measured (1000 Hz) using a force platform (BERTEC 4060-15), an amplifier (BERTEC AM 6300) and an analogical-digital converter of 16 Bits (Biopac). RESULTS: The study showed that there were significant differences among the two groups concerning absolute values of time of the stance phase. In what concerns to the normalized values the most significant differences were verified in the maximums values of vertical force (Fz3, Fz1) and in the impulse of the antero-posterior force (Fy2), taxes of growth of the vertical force, and in the period of time for the antero-posterior force (Fy) be null. CONCLUSIONS: It is easier for the pregnant to continue forward movement (push-off phase). O smaller growth rates in what concerns to the maximum of the vertical force (Fz1) for the pregnant, can be associated with a slower speed of gait, as an adaptation strategy to maintain the balance, to compensate the alterations in the position of her center of gravity due to the load increase. The data related to the antero-posterior component of the force (Fy), shows that there is a significant difference between the pregnant woman’s left foot and right foot, which accuses a different functional behavior in each one of the feet, during the propulsion phase (TS).

Real-time energy resources scheduling considering intensive wind penetration

The use of distributed energy resources, based on natural intermittent power sources, like wind generation, in power systems imposes the development of new adequate operation management and control methodologies. A short-term Energy Resource Management (ERM) methodology performed in two phases is proposed in this paper. The first one addresses the day-ahead ERM scheduling and the second one deals with the five-minute ahead ERM scheduling. The ERM scheduling is a complex optimization problem due to the high quantity of variables and constraints. In this paper the main goal is to minimize the operation costs from the point of view of a virtual power player that manages the network and the existing resources. The optimization problem is solved by a deterministic mixedinteger non-linear programming approach. A case study considering a distribution network with 33 bus, 66 distributed generation, 32 loads with demand response contracts and 7 storage units and 1000 electric vehicles has been implemented in a simulator developed in the field of the presented work, in order to validate the proposed short-term ERM methodology considering the dynamic power system behavior.

Intelligent electric vehicle heuristic for energy resource management using simulated annealing

The smart grid concept appears as a suitable solution to guarantee the power system operation in the new electricity paradigm with electricity markets and integration of large amounts of Distributed Energy Resources (DERs). Virtual Power Player (VPP) will have a significant importance in the management of a smart grid. In the context of this new paradigm, Electric Vehicles (EVs) rise as a good available resource to be used as a DER by a VPP. This paper presents the application of the Simulated Annealing (SA) technique to solve the Energy Resource Management (ERM) of a VPP. It is also presented a new heuristic approach to intelligently handle the charge and discharge of the EVs. This heuristic process is incorporated in the SA technique, in order to improve the results of the ERM. The case study shows the results of the ERM for a 33-bus distribution network with three different EVs penetration levels, i. e., with 1000, 2000 and 3000 EVs. The results of the proposed adaptation of the SA technique are compared with a previous SA version and a deterministic technique.

Intelligent energy resource management considering vehicle-to-grid: A simulated annealing approach

This paper proposes a simulated annealing (SA) approach to address energy resources management from the point of view of a virtual power player (VPP) operating in a smart grid. Distributed generation, demand response, and gridable vehicles are intelligently managed on a multiperiod basis according to V2G user´s profiles and requirements. Apart from using the aggregated resources, the VPP can also purchase additional energy from a set of external suppliers. The paper includes a case study for a 33 bus distribution network with 66 generators, 32 loads, and 1000 gridable vehicles. The results of the SA approach are compared with a methodology based on mixed-integer nonlinear programming. A variation of this method, using ac load flow, is also used and the results are compared with the SA solution using network simulation. The proposed SA approach proved to be able to obtain good solutions in low execution times, providing VPPs with suitable decision support for the management of a large number of distributed resources.

Distribution network short term scheduling in Smart Grid context

The large increase of Distributed Generation (DG) in Power Systems (PS) and specially in distribution networks makes the management of distribution generation resources an increasingly important issue. Beyond DG, other resources such as storage systems and demand response must be managed in order to obtain more efficient and “green” operation of PS. More players, such as aggregators or Virtual Power Players (VPP), that operate these kinds of resources will be appearing. This paper proposes a new methodology to solve the distribution network short term scheduling problem in the Smart Grid context. This methodology is based on a Genetic Algorithms (GA) approach for energy resource scheduling optimization and on PSCAD software to obtain realistic results for power system simulation. The paper includes a case study with 99 distributed generators, 208 loads and 27 storage units. The GA results for the determination of the economic dispatch considering the generation forecast, storage management and load curtailment in each period (one hour) are compared with the ones obtained with a Mixed Integer Non-Linear Programming (MINLP) approach.

Using data mining techniques to support DR programs definition in smart grids

In recent years, Power Systems (PS) have experimented many changes in their operation. The introduction of new players managing Distributed Generation (DG) units, and the existence of new Demand Response (DR) programs make the control of the system a more complex problem and allow a more flexible management. An intelligent resource management in the context of smart grids is of huge important so that smart grids functions are assured. This paper proposes a new methodology to support system operators and/or Virtual Power Players (VPPs) to determine effective and efficient DR programs that can be put into practice. This method is based on the use of data mining techniques applied to a database which is obtained for a large set of operation scenarios. The paper includes a case study based on 27,000 scenarios considering a diversity of distributed resources in a 32 bus distribution network.

VPP´s multi-level negotiation in smart grids and competitive electricity markets

The increase of distributed generation (DG) has brought about new challenges in electrical networks electricity markets and in DG units operation and management. Several approaches are being developed to manage the emerging potential of DG, such as Virtual Power Players (VPPs), which aggregate DG plants; and Smart Grids, an approach that views generation and associated loads as a subsystem. This paper presents a multi-level negotiation mechanism for Smart Grids optimal operation and negotiation in the electricity markets, considering the advantages of VPPs’ management. The proposed methodology is implemented and tested in MASCEM – a multiagent electricity market simulator, developed to allow deep studies of the interactions between the players that take part in the electricity market negotiations.

LMP based bid formation for virtual power players operating in smart grids

Power system organization has gone through huge changes in the recent years. Significant increase in distributed generation (DG) and operation in the scope of liberalized markets are two relevant driving forces for these changes. More recently, the smart grid (SG) concept gained increased importance, and is being seen as a paradigm able to support power system requirements for the future. This paper proposes a computational architecture to support day-ahead Virtual Power Player (VPP) bid formation in the smart grid context. This architecture includes a forecasting module, a resource optimization and Locational Marginal Price (LMP) computation module, and a bid formation module. Due to the involved problems characteristics, the implementation of this architecture requires the use of Artificial Intelligence (AI) techniques. Artificial Neural Networks (ANN) are used for resource and load forecasting and Evolutionary Particle Swarm Optimization (EPSO) is used for energy resource scheduling. The paper presents a case study that considers a 33 bus distribution network that includes 67 distributed generators, 32 loads and 9 storage units.

Simulated annealing metaheuristic to solve the optimal power flow

The optimal power flow problem has been widely studied in order to improve power systems operation and planning. For real power systems, the problem is formulated as a non-linear and as a large combinatorial problem. The first approaches used to solve this problem were based on mathematical methods which required huge computational efforts. Lately, artificial intelligence techniques, such as metaheuristics based on biological processes, were adopted. Metaheuristics require lower computational resources, which is a clear advantage for addressing the problem in large power systems. This paper proposes a methodology to solve optimal power flow on economic dispatch context using a Simulated Annealing algorithm inspired on the cooling temperature process seen in metallurgy. The main contribution of the proposed method is the specific neighborhood generation according to the optimal power flow problem characteristics. The proposed methodology has been tested with IEEE 6 bus and 30 bus networks. The obtained results are compared with other wellknown methodologies presented in the literature, showing the effectiveness of the proposed method.

Ant colony search algorithm for the optimal power flow problem

To maintain a power system within operation limits, a level ahead planning it is necessary to apply competitive techniques to solve the optimal power flow (OPF). OPF is a non-linear and a large combinatorial problem. The Ant Colony Search (ACS) optimization algorithm is inspired by the organized natural movement of real ants and has been successfully applied to different large combinatorial optimization problems. This paper presents an implementation of Ant Colony optimization to solve the OPF in an economic dispatch context. The proposed methodology has been developed to be used for maintenance and repairing planning with 48 to 24 hours antecipation. The main advantage of this method is its low execution time that allows the use of OPF when a large set of scenarios has to be analyzed. The paper includes a case study using the IEEE 30 bus network. The results are compared with other well-known methodologies presented in the literature.

O Contributo da auditoria interna para uma gestão eficaz

Com a globalização da economia e o crescimento dos mercados financeiros, surge cada vez mais a necessidade de obter informação útil e atempada, que permita aos gestores das organizações tomar as melhores decisões para a consecução dos objectivos e para o desenvolvimento de estratégias. É neste contexto que a auditoria interna assume um papel relevante, indo ao encontro dos interesses dos gestores, na medida em que audita não só os procedimentos relativos ao reporte financeiro, como também todos os outros procedimentos de controlo interno, contribuindo assim para um controlo mais amplo e completo em toda a organização. O presente trabalho tem como objectivo verificar até que ponto a auditoria interna contribui para uma gestão eficaz das organizações. Para tal, realizaram-se pesquisas sobre os principais conceitos, funções e procedimentos relacionados com auditoria interna e a sua relação com a gestão das organizações. Seguidamente, procedeu-se à explicação da metodologia praticada e à exposição do caso empírico, que teve como base a elaboração de dois questionários basicamente semelhantes, que foram enviados às 200 empresas que apresentaram maior Volume de Negócios, retiradas do universo das “1000 MAIORES EMPRESAS” a actuarem no mercado português durante o ano de 2010. Esses questionários tiveram como objectivo cruzar as opiniões de gestores e auditores, a fim de concluir se existe ou não um contributo da auditoria interna para uma gestão eficaz. Na posse da informação recolhida foi possível ressaltar o contributo da auditoria interna como ferramenta indispensável para uma gestão eficaz, no sentido que procura adequar os custos, aumentar a produtividade, auxiliar no processo de gestão dos riscos e no processo de tomada de decisão, de modo a tornar as organizações mais competitivas e garantindo-lhes um crescimento sustentado.

A Intenção de uso da M-Wallet pelo consumidor português

Dissertação de Mestrado apresentada ao Instituto de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Marketing Digital, sob orientação de Mestre António da Silva Vieira.

O Comportamento de consumo de Vinho do Porto dos portugueses – recomendações para o aumento da procura interna

Dissertação de Mestrado apresentada ao Instituto de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Marketing Digital, sob orientação de Doutor António Correia de Barros

Produção de biomassa aquática como fonte de lípidos para biocombustíveis

Mestrado em Engenharia Química. Ramo Tecnologias de Protecção Ambiental.

Implementação do rastreio auditivo neonatal universal de surdez no Hospital CUF Porto

A incidência de perda auditiva bilateral é de 1 a 3 por cada recém-nascidos saudáveis e de 30 a 40 por 1000 recém-nascidos de risco. No Hospital Cuf Porto (HCP) o Rastreio Auditivo Neonatal Universal (RANU) teve inicio em Dezembro de 2010 em paralelo com abertura dos serviços de Obstetrícia / Neonatologia. As otoemissões acústicas (OEA) são o teste utilizado pois são reconhecidas como um método de rastreio auditivo simples, seguro e bem aceite. O objectivo deste trabalho é salientar a importância do RANU na identificação da perda auditiva antes da alta hospitalar, apresentando as suas vantagens na detecção e intervenção precoce minimizando as consequências da perda auditiva. Este trabalho, pretende ainda demonstrar as vantagens do RANU como estratégia fundamental no planeamento e na introdução de medidas de diagnóstico e terapêutica. É assim apresentada uma análise retrospectiva dos resultados obtidos nas OEA por produtos de distorção (OEAPD) entre Janeiro de 2011 e Dezembro de 2012, com uma amostra constituída por n=572. Os resultados revelam uma percentagem de “PASS” (OEAPD presentes) na primeira fase do rastreio, com um valor de 88,8% relativamente ao número total de rastreios efectuados. Relativamente à percentagem de “REFER” (OEAPD ausentes) – na mesma fase do rastreio- obtiveram-se 11,2% de situações face ao total de rastreados. Destes – que correspondem a um n=64 – 42.2% das situações referem-se a “REFER” bilateral (n=27). Relativamente às situações de “REFER” unilateral (n=37), encontramos uma percentagem de 57,8% dos casos. De acordo com a casuística apresentada, correspondente aos resultados obtidos e atendendo à realidade da população rastreada (dado que até ao momento não se confirmou perda auditiva em nenhum dos indivíduos rastreados), pode-se concluir que os OEA podem ser um método de rastreio simples e fiável, fundamental para a detecção e intervenção precoce nas perdas auditivas.