47 resultados para Implementation accuracy
em Instituto Politécnico do Porto, Portugal
Resumo:
Currently, power systems (PS) already accommodate a substantial penetration of distributed generation (DG) and operate in competitive environments. In the future, as the result of the liberalisation and political regulations, PS will have to deal with large-scale integration of DG and other distributed energy resources (DER), such as storage and provide market agents to ensure a flexible and secure operation. This cannot be done with the traditional PS operational tools used today like the quite restricted information systems Supervisory Control and Data Acquisition (SCADA) [1]. The trend to use the local generation in the active operation of the power system requires new solutions for data management system. The relevant standards have been developed separately in the last few years so there is a need to unify them in order to receive a common and interoperable solution. For the distribution operation the CIM models described in the IEC 61968/70 are especially relevant. In Europe dispersed and renewable energy resources (D&RER) are mostly operated without remote control mechanisms and feed the maximal amount of available power into the grid. To improve the network operation performance the idea of virtual power plants (VPP) will become a reality. In the future power generation of D&RER will be scheduled with a high accuracy. In order to realize VPP decentralized energy management, communication facilities are needed that have standardized interfaces and protocols. IEC 61850 is suitable to serve as a general standard for all communication tasks in power systems [2]. The paper deals with international activities and experiences in the implementation of a new data management and communication concept in the distribution system. The difficulties in the coordination of the inconsistent developed in parallel communication and data management standards - are first addressed in the paper. The upcoming unification work taking into account the growing role of D&RER in the PS is shown. It is possible to overcome the lag in current practical experiences using new tools for creating and maintenance the CIM data and simulation of the IEC 61850 protocol – the prototype of which is presented in the paper –. The origin and the accuracy of the data requirements depend on the data use (e.g. operation or planning) so some remarks concerning the definition of the digital interface incorporated in the merging unit idea from the power utility point of view are presented in the paper too. To summarize some required future work has been identified.
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Although the Navigation Satellite Timing and Ranging (NAVSTAR) Global Positioning System (GPS) is, de facto, the standard positioning system used in outdoor navigation, it does not provide, per se, all the features required to perform many outdoor navigational tasks. The accuracy of the GPS measurements is the most critical issue. The quest for higher position readings accuracy led to the development, in the late nineties, of the Differential Global Positioning System (DGPS). The differential GPS method detects the range errors of the GPS satellites received and broadcasts them. The DGPS/GPS receivers correlate the DGPS data with the GPS satellite data they are receiving, granting users increased accuracy. DGPS data is broadcasted using terrestrial radio beacons, satellites and, more recently, the Internet. Our goal is to have access, within the ISEP campus, to DGPS correction data. To achieve this objective we designed and implemented a distributed system composed of two main modules which are interconnected: a distributed application responsible for the establishment of the data link over the Internet between the remote DGPS stations and the campus, and the campus-wide DGPS data server application. The DGPS data Internet link is provided by a two-tier client/server distributed application where the server-side is connected to the DGPS station and the client-side is located at the campus. The second unit, the campus DGPS data server application, diffuses DGPS data received at the campus via the Intranet and via a wireless data link. The wireless broadcast is intended for DGPS/GPS portable receivers equipped with an air interface and the Intranet link is provided for DGPS/GPS receivers with just a RS232 DGPS data interface. While the DGPS data Internet link servers receive the DGPS data from the DGPS base stations and forward it to the DGPS data Internet link client, the DGPS data Internet link client outputs the received DGPS data to the campus DGPS data server application. The distributed system is expected to provide adequate support for accurate (sub-metric) outdoor campus navigation tasks. This paper describes in detail the overall distributed application.
Resumo:
The design and development of simulation models and tools for Demand Response (DR) programs are becoming more and more important for adequately taking the maximum advantages of DR programs use. Moreover, a more active consumers’ participation in DR programs can help improving the system reliability and decrease or defer the required investments. DemSi, a DR simulator, designed and implemented by the authors of this paper, allows studying DR actions and schemes in distribution networks. It undertakes the technical validation of the solution using realistic network simulation based on PSCAD. DemSi considers the players involved in DR actions, and the results can be analyzed from each specific player point of view.
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This paper presents a new architecture for the MASCEM, a multi-agent electricity market simulator. This is implemented in a Prolog which is integrated in the JAVA program by using the LPA Win-Prolog Intelligence Server (IS) provides a DLL interface between Win-Prolog and other applications. This paper mainly focus on the MASCEM ability to provide the means to model and simulate Virtual Power Producers (VPP). VPPs are represented as a coalition of agents, with specific characteristics and goals. VPPs can reinforce the importance of these generation technologies making them valuable in electricity markets.
Resumo:
Human Computer Interaction (HCl) is to interaction between computers and each person. And context-aware (CA) is very important one of HCI composition. In particular, if there are sequential or continuous tasks between users and devices, among users, and among devices etc, it is important to decide the next action using right CA. And to take perfect decision we have to get together all CA into a structure. We define that structure is Context-Aware Matrix (CAM) in this article. However to make exact decision is too hard for some problems like low accuracy, overhead and bad context by attacker etc. Many researcher has been studying to solve these problems. Moreover, still it has weak point HCI using in safety. In this Article, we propose CAM making include best selecting Server in each area. As a result, moving users could be taken the best way.
Resumo:
Mestrado em Engenharia Electrotécnica e de Computadores
Resumo:
Mestrado em Engenharia Electrotécnica e de Computadores.
Resumo:
A maximização do potencial da abordagem cirúrgica conservadora da axila para o cancro da mama, como um método minimamente invasivo para a avaliação de metastização axilar, visando diminuir a morbilidade associada ao esvaziamento axilar completo, requer um método preciso para avaliação patológica intraoperatória. Esse método não foi ainda estabelecido. Imprints e corte de congelação do gânglio sentinela são os procedimentos comummente utilizados, apesar de uma sensibilidade e especificidade inferior à desejada. Actualmente, novas técnicas estão a ser desenvolvidas, que apesar da sua optimização, ainda não ultrapassam os resultados das utilizadas. Um total de 138 mulheres com cancro da mama, submetidas a cirurgia mamária por abordagem conservadora da axila, cuja utilização de imprints e cortes de congelação foram os métodos de avaliação intraoperatória do gânglio sentinela. Os diagnósticos dados pela observação dos cortes dos fragmentos do exame extemporâneo foram comparados com os obtidos nos cortes histológicos definitivos dos fragmentos fixados em formol e incluídos em parafina. Os resultados obtidos da avaliação do exame extemporâneo demonstraram sensibilidade de 79,1%, especificidade de 96,9%, com uma precisão de 91,4%. Não se obteve correlação entre os resultados do extemporâneo e os parâmetros de caracterização do exame extemporâneo e tumores. Os métodos, imprints e cortes de congelação, actualmente utilizados na nossa instituição apresentam bons resultados, mas a adopção de apenas um ou outro necessita de uma análise mais aprofundada dos dados relativos à metodologia utilizada nos extemporâneos, de forma a verificar a especificidade e sensibilidade individualizadas dos imprints e dos cortes de congelação. Se os imprints se revelarem semelhantes aos cortes de congelação, a sua utilização é preferencial uma vez que acarreta menores custos e são menos morosos. A implementação de novas técnicas será uma metodologia adoptar, pelos benefícios acrescidos, porém mais estudos e a optimização
Resumo:
The constant evolution of the Internet and its increasing use and subsequent entailing to private and public activities, resulting in a strong impact on their survival, originates an emerging technology. Through cloud computing, it is possible to abstract users from the lower layers to the business, focusing only on what is most important to manage and with the advantage of being able to grow (or degrades) resources as needed. The paradigm of cloud arises from the necessity of optimization of IT resources evolving in an emergent and rapidly expanding and technology. In this regard, after a study of the most common cloud platforms and the tactic of the current implementation of the technologies applied at the Institute of Biomedical Sciences of Abel Salazar and Faculty of Pharmacy of Oporto University a proposed evolution is suggested in order adorn certain requirements in the context of cloud computing.
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Este trabalho pretende avaliar e melhorar o modo de execução da aplicação da técnica de rebentamento com explosivos, aumentando a fragmentação e reduzindo o custo no conjunto das operações de perfuração, carga, detonação e fragmentação secundária e compreender a influência na variação do custo das operações face às melhorias adoptadas. A investigação foi executada na pedreira da Mota-Engil, Engenharia S.A. ‘’ Bouça do Menino’’ Vila Verde, Cervães, tendo os dados iniciais sido recolhidos em 2004 (ano de referência) e comparados com os seguintes 4 anos. A perfuração é geralmente um dos principais factores que influenciam o resultado de um rebentamento, já que do seu rigor pode depender a eficiência do explosivo. Hoje em dia, para além da adequação dos métodos de execução ao local a fragmentar, existem ferramentas que nos permitem visualizar com rigor as circunstâncias em que se desenvolvem os trabalhos, nomeadamente as utilizadas pelos equipamentos de perfuração para controlo de profundidade, inclinação e direcção, a utilização de feixes ‘’laser’’ que nos permitem manter o nivelamento das plataformas, o ‘’laser’’ profile que nos ajuda a definir o posicionamento e inclinação dos furos relativamente à frente livre antes de executar a perfuração, ou ainda, a utilização de equipamentos de registo de coordenadas que nos permitem verificar o posicionamento do furo após a sua execução e decidir sobre a sua utilização mais correcta em função da sua posição. A utilização destas ferramentas associadas a um ‘’software’’ de desenho é ainda uma excelente ferramenta de formação para os operadores da perfuração e utilização dos explosivos, já que permite visualizar e compreender a relação da posição dos furos com o resultado do rebentamento.
Resumo:
Absolute positioning – the real time satellite based positioning technique that relies solely on global navigation satellite systems – lacks accuracy for several real time application domains. To provide increased positioning quality, ground or satellite based augmentation systems can be devised, depending on the extent of the area to cover. The underlying technique – multiple reference station differential positioning – can, in the case of ground systems, be further enhanced through the implementation of the virtual reference station concept. Our approach is a ground based system made of a small-sized network of three stations where the concept of virtual reference station was implemented. The stations provide code pseudorange corrections, which are combined using a measurement domain approach inversely proportional to the distance from source station to rover. All data links are established trough the Internet.
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In this paper we discuss challenges and design principles of an implementation of slot-based tasksplitting algorithms into the Linux 2.6.34 version. We show that this kernel version is provided with the required features for implementing such scheduling algorithms. We show that the real behavior of the scheduling algorithm is very close to the theoretical. We run and discuss experiments on 4-core and 24-core machines.
Resumo:
As the complexity of embedded systems increases, multiple services have to compete for the limited resources of a single device. This situation is particularly critical for small embedded devices used in consumer electronics, telecommunication, industrial automation, or automotive systems. In fact, in order to satisfy a set of constraints related to weight, space, and energy consumption, these systems are typically built using microprocessors with lower processing power and limited resources. The CooperatES framework has recently been proposed to tackle these challenges, allowing resource constrained devices to collectively execute services with their neighbours in order to fulfil the complex Quality of Service (QoS) constraints imposed by users and applications. In order to demonstrate the framework's concepts, a prototype is being implemented in the Android platform. This paper discusses key challenges that must be addressed and possible directions to incorporate the desired real-time behaviour in Android.
Resumo:
The IEEE 802.15.4 is the most widespread used protocol for Wireless Sensor Networks (WSNs) and it is being used as a baseline for several higher layer protocols such as ZigBee, 6LoWPAN or WirelessHART. Its MAC (Medium Access Control) supports both contention-free (CFP, based on the reservation of guaranteed time-slots GTS) and contention based (CAP, ruled by CSMA/CA) access, when operating in beacon-enabled mode. Thus, it enables the differentiation between real-time and best-effort traffic. However, some WSN applications and higher layer protocols may strongly benefit from the possibility of supporting more traffic classes. This happens, for instance, for dense WSNs used in time-sensitive industrial applications. In this context, we propose to differentiate traffic classes within the CAP, enabling lower transmission delays and higher success probability to timecritical messages, such as for event detection, GTS reservation and network management. Building upon a previously proposed methodology (TRADIF), in this paper we outline its implementation and experimental validation over a real-time operating system. Importantly, TRADIF is fully backward compatible with the IEEE 802.15.4 standard, enabling to create different traffic classes just by tuning some MAC parameters.
Resumo:
The IEEE 802.15.4/ZigBee protocols are gaining increasing interests in both research and industrial communities as candidate technologies for Wireless Sensor Network (WSN) applications. In this paper, we present an open-source implementation of the IEEE 802.15.4/Zigbee protocol stack under the TinyOS operating system for the MICAz motes. This work has been driven by the need for an open-source implementation of the IEEE 802.15.4/ZigBee protocols, filling a gap between some newly released complex C implementations and black-box implementations from different manufacturers. In addition, we share our experience on the challenging problem that we have faced during the implementation of the protocol stack on the MICAz motes. We strongly believe that this open-source implementation will potentiate research works on the IEEE 802.15.4/Zigbee protocols allowing their demonstration and validation through experimentation.