960 resultados para pacs: television systems for office automation


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El software lliure est tenint ltimament un pes cada cop ms important en les empreses, per encara s el gran desconegut per a molta gent. Des de la seva creaci als anys 80 fins ara, hi ha hagut un creixement exponencial de software lliure de gran qualitat, oferint eines per a tot tipus de necessitats, eines ofimtiques, gestors de correu, sistemes de fitxer, sistemes operatius. Tot aquest moviment no ha passat desapercebut per a molts usuaris i empreses, que shan aprofitat dell per cobrir les seves necessitats. Pel que fa a les empreses, cada cop nhi ha ms que en petita o gran mesura, utilitzen el software lliure, ja sigui per el seu menor cost dadquisici, o b per la seva gran fiabilitat o per que s fcilment adaptable o per no establir cap lligam tecnolgic, en definitiva per tenir ms llibertat. En el moment de la creaci duna nova empresa, on es parteix de zero en tota la tecnologia informtica, s el moment menys costs dimplementar larquitectura informtica amb software lliure, s quan limpacte que t sobre lempresa, usuaris i clients s menor. En les empreses que ja tenen un sistema informtic, caldr establir un pla de migraci, ja sigui total o parcial. La finalitat daquest projecte no s la de dir quin software s millor que laltre o de dir quin sha dinstallar, sin el de donar a conixer el mn del software lliure, mostrar part daquest software, fer alguna comparativa de software lliure amb software propietari, donant idees i un conjunt de solucions per a empreses, per qu una empresa pugui agafar idees dimplementaci dalgunes de les solucions informtiques exposades o seguir algun dels consells proposats. Actualment ja hi ha moltes empreses que utilitzen software lliure. Algunes noms nutilitzen una petita part en les seves installacions, ja que el fet de que una empresa funcioni al 100% amb software lliure, tot i que nhi comena ha haver, de moment ho considero una mica arriscat, per que en poc temps, aquest fet ser cada cop ms habitual.

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Smooth flow of production in construction is hampered by disparity between individual trade teams' goals and the goals of stable production flow for the project as a whole. This is exacerbated by the difficulty of visualizing the flow of work in a construction project. While the addresses some of the issues in Building information modeling provides a powerful platform for visualizing work flow in control systems that also enable pull flow and deeper collaboration between teams on and off site. The requirements for implementation of a BIM-enabled pull flow construction management software system based on the Last Planner System, called KanBIM, have been specified, and a set of functional mock-ups of the proposed system has been implemented and evaluated in a series of three focus group workshops. The requirements cover the areas of maintenance of work flow stability, enabling negotiation and commitment between teams, lean production planning with sophisticated pull flow control, and effective communication and visualization of flow. The evaluation results show that the system holds the potential to improve work flow and reduce waste by providing both process and product visualization at the work face.

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In this paper, we propose an extension of the invariance principle for nonlinear switched systems under dwell-time switched solutions. This extension allows the derivative of an auxiliary function V, also called a Lyapunov-like function, along the solutions of the switched system to be positive on some sets. The results of this paper are useful to estimate attractors of nonlinear switched systems and corresponding basins of attraction. Uniform estimates of attractors and basin of attractions with respect to time-invariant uncertain parameters are also obtained. Results for a common Lyapunov-like function and multiple Lyapunov-like functions are given. Illustrative examples show the potential of the theoretical results in providing information on the asymptotic behavior of nonlinear dynamical switched systems. (C) 2012 Elsevier B.V. All rights reserved.

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Building facilities have become important infrastructures for modern productive plants dedicated to services. In this context, the control systems of intelligent buildings have evolved while their reliability has evidently improved. However, the occurrence of faults is inevitable in systems conceived, constructed and operated by humans. Thus, a practical alternative approach is found to be very useful to reduce the consequences of faults. Yet, only few publications address intelligent building modeling processes that take into consideration the occurrence of faults and how to manage their consequences. In the light of the foregoing, a procedure is proposed for the modeling of intelligent building control systems, considersing their functional specifications in normal operation and in the of the event of faults. The proposed procedure adopts the concepts of discrete event systems and holons, and explores Petri nets and their extensions so as to represent the structure and operation of control systems for intelligent buildings under normal and abnormal situations. (C) 2012 Elsevier B.V. All rights reserved.

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Das Interesse an Online-Vorlesungen, -Vortrgen oder -Prsentationen fr E-Learning hat deutlich zugenommen. Hierfr gibt es eine Reihe von Grnden, die mit neuen Formen der Produktion und Distribution von Online-Vorlesungen zusammenhngen. Mit der Verfgbarkeit von Rapid-Authoring-Werkzeugen wird der Workflow fr die Erstellung und den Einsatz von Online-Vorlesungen erleichtert und flexibilisiert. Hierbei ist zu beobachten, dass durch die Vielzahl der Mglichkeiten im Workflow zunehmend individuelle Rahmenbedingungen und Anforderungen bercksichtigt werden knnen. Der folgende Beitrag beschreibt diese Vernderungen. Er fasst die Optionen im Prozess der Produktion und Distribution von Online-Vortrgen im Internet zusammen. Ein solcher berblick ber das Themengebiet ist erforderlich fr das Herausarbeiten eines individuellen Workflows. Hierzu werden Entscheidungskriterien fr die Auswahl von Werkzeugen und Plattformen dargestellt und die mediendidaktischen Implikationen diskutiert.

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Under the brand name sciebo the Campuscloud (derived from science box) a consortium of more than 20 research and applied science universities started a large scale cloud service for about 500,000 students and researchers in North Rhine-Westphalia, Germanys most populous state. Starting with the much anticipated data privacy compliant sync & share functionality, sciebo offers the potential to become a more general cloud platform for collaboration and research data management which will be actively pursued in upcoming scientific and infrastructural projects. This project report describes the formation of the venture, its targets and the technical and the legal solution as well as the current status and the next steps.

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Mode of access: Internet.

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The pervasiveness of information systems (IS) in organizations mandates the need for high levels of IS skills. In recognition, professional bodies impose IS course requirements for accreditation. For both students and employers, performance in IS courses has become important. The tertiary entrance overall performance score accounted for 19.7 per cent of the variance in students' passing grades. Thereafter, proficiency in office automation software and programming accounted for 1.5 and 0.8 per cent of the variance, respectively. Students living in a stable, family home-based environment performed better and it is likely that this environment underpinned other factors affecting performance.

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This paper develops a Markovian jump model to describe the fault occurrence in a manipulator robot of three joints. This model includes the changes of operation points and the probability that a fault occurs in an actuator. After a fault, the robot works as a manipulator with free joints. Based on the developed model, a comparative study among three Markovian controllers, H(2), H(infinity), and mixed H(2)/H(infinity) is presented, applied in an actual manipulator robot subject to one and two consecutive faults.

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In this work, a stable MPC that maximizes the domain of attraction of the closed-loop system is proposed. The proposed approach is suitable to real applications in the sense that it accounts for the case of output tracking, it is offset free if the output target is reachable and minimizes the offset if some of the constraints are active at steady state. The new approach is based on the definition of a Minkowski functional related to the input and terminal constraints of the stable infinite horizon MPC. It is also shown that the domain of attraction is defined by the system model and the constraints, and it does not depend on the controller tuning parameters. The proposed controller is illustrated with small order examples of the control literature. (C) 2011 Elsevier Ltd. All rights reserved.

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Model predictive control (MPC) is usually implemented as a control strategy where the system outputs are controlled within specified zones, instead of fixed set points. One strategy to implement the zone control is by means of the selection of different weights for the output error in the control cost function. A disadvantage of this approach is that closed-loop stability cannot be guaranteed, as a different linear controller may be activated at each time step. A way to implement a stable zone control is by means of the use of an infinite horizon cost in which the set point is an additional variable of the control problem. In this case, the set point is restricted to remain inside the output zone and an appropriate output slack variable is included in the optimisation problem to assure the recursive feasibility of the control optimisation problem. Following this approach, a robust MPC is developed for the case of multi-model uncertainty of open-loop stable systems. The controller is devoted to maintain the outputs within their corresponding feasible zone, while reaching the desired optimal input target. Simulation of a process of the oil re. ning industry illustrates the performance of the proposed strategy.

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Electromagnetic suspension systems are inherently nonlinear and often face hardware limitation when digitally controlled. The main contributions of this paper are: the design of a nonlinear H(infinity) controller. including dynamic weighting functions, applied to a large gap electromagnetic suspension system and the presentation of a procedure to implement this controller on a fixed-point DSP, through a methodology able to translate a floating-point algorithm into a fixed-point algorithm by using l(infinity) norm minimization due to conversion error. Experimental results are also presented, in which the performance of the nonlinear controller is evaluated specifically in the initial suspension phase. (C) 2009 Elsevier Ltd. All rights reserved.

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A concepo de instalaes elctricas deve garantir condies de segurana para as pessoas e equipamentos. Para tal exigida, quer por fora de regulamentao ou de normalizao, a instalao de dispositivos que garantam a deteco e a proteco contra os defeitos mais comuns nas instalaes elctricas como, por exemplo, as sobreintensidades e as sobretenses. Susceptveis de criar sobretenses perigosas nas instalaes elctricas, as descargas atmosfricas podem ainda causar danos estruturais elevados, o que, em algumas actividades econmicas, torna fundamental a implementao de medidas de proteco contra este fenmeno natural. A proteco contra descargas atmosfricas directas consiste em identificar as vulnerabilidades das estruturas e, nesses locais, implementar dispositivos de captura, direccionamento e escoamento da descarga atmosfrica terra, em condies de segurana. O presente trabalho, desenvolvido no mbito da dissertao de Mestrado em Engenharia Electrotcnica, visa desenvolver e implementar uma ferramenta computacional, baseada em programas de desenho assistido por computador (CAD) de utilizao corrente na rea de projecto de arquitectura e de engenharia, que permita, no mbito de normas internacionais, a anlise e implementao de sistemas de proteco em edifcios contra descargas atmosfricas de uma forma rpida e expedita. Baseado num programa CAD 3D, que permite a modelizao tridimensional das estruturas a proteger, a ferramenta desenvolvida tentar identificar as suas vulnerabilidades das estruturas s descargas atmosfricas directas, com o intuito de implementar as medidas de proteco mais adequadas do ponto de vista tcnico econmico. Prev-se que a ferramenta resultante deste estudo, o Simulador do Modelo Electrogeomtrico (SIMODEL), possibilite aos projectistas e particularmente aos alunos das unidades curriculares na rea do projecto de instalaes elctricas da rea Departamental de Engenharia de Sistemas e Potencia e Automao (ADESPA) do ISEL, estudar e implementar sistemas de proteco contra descargas atmosfricas (SPDA) baseados na normalizao internacional do CENELEC e da IEC, nomeadamente as normas da srie 62305.

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In the context of electricity markets, transmission pricing is an important tool to achieve an efficient operation of the electricity system. The electricity market is influenced by several factors; however the transmission network management is one of the most important aspects, because the network is a natural monopoly. The transmission tariffs can help to regulate the market, for this reason transmission tariffs must follow strict criteria. This paper presents the following methods to tariff the use of transmission networks by electricity market players: Post-Stamp Method; MW-Mile Method Distribution Factors Methods; Tracing Methodology; Bialeks Tracing Method and Locational Marginal Price. A nine bus transmission network is used to illustrate the application of the tariff methods.

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This paper introduces the PCMAT platform project and, in particular, one of its components, the PCMAT Metadata Authoring Tool. This is an educational web application that allows the project metadata creators to write the metadata associated to each learning object without any concern for the metadata schema semantics. Furthermore it permits the project managers to add or delete elements to the schema, without having to rewrite or compile any code.