Estudi de software lliure en diferents entorns

El software lliure est�� tenint ��ltimament un pes cada cop m��s 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 ofim��tiques, gestors de correu, sistemes de fitxer, sistemes operatius���. Tot aquest moviment no ha passat desapercebut per a molts usuaris i empreses, que s���han aprofitat d���ell per cobrir les seves necessitats. Pel que fa a les empreses, cada cop n���hi ha m��s que en petita o gran mesura, utilitzen el software lliure, ja sigui per el seu menor cost d���adquisici��, o b�� per la seva gran fiabilitat o per que ��s f��cilment adaptable o per no establir cap lligam tecnol��gic, en definitiva per tenir m��s llibertat. En el moment de la creaci�� d���una nova empresa, on es parteix de zero en tota la tecnologia inform��tica, ��s el moment menys cost��s d���implementar l���arquitectura inform��tica amb software lliure, ��s quan l���impacte que t�� sobre l���empresa, usuaris i clients ��s menor. En les empreses que ja tenen un sistema inform��tic, caldr�� establir un pla de migraci��, ja sigui total o parcial. La finalitat d���aquest projecte no ��s la de dir quin software ��s millor que l���altre o de dir quin s���ha d���instal���lar, sin�� el de donar a con��ixer el m��n del software lliure, mostrar part d���aquest 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 d���implementaci�� d���algunes de les solucions inform��tiques exposades o seguir algun dels consells proposats. Actualment ja hi ha moltes empreses que utilitzen software lliure. Algunes nom��s n���utilitzen una petita part en les seves instal���lacions, ja que el fet de que una empresa funcioni al 100% amb software lliure, tot i que n���hi comen��a ha haver, de moment ho considero una mica arriscat, per�� que en poc temps, aquest fet ser�� cada cop m��s habitual.

Requirements for building information modeling based lean production management systems for construction

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.

An extension of the invariance principle for dwell-time switched nonlinear systems

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.

Modeling of active holonic control systems for intelligent buildings

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.

Darstellung von Entscheidungskriterien zur Produktion und Distribution von Online-Vorlesungen

Das Interesse an Online-Vorlesungen, -Vortr��gen oder -Pr��sentationen f��r E-Learning hat deutlich zugenommen. Hierf��r gibt es eine Reihe von Gr��nden, die mit neuen Formen der Produktion und Distribution von Online-Vorlesungen zusammenh��ngen. Mit der Verf��gbarkeit von Rapid-Authoring-Werkzeugen wird der Workflow f��r die Erstellung und den Einsatz von Online-Vorlesungen erleichtert und flexibilisiert. Hierbei ist zu beobachten, dass durch die Vielzahl der M��glichkeiten im Workflow zunehmend individuelle Rahmenbedingungen und Anforderungen ber��cksichtigt werden k��nnen. Der folgende Beitrag beschreibt diese Ver��nderungen. Er fasst die Optionen im Prozess der Produktion und Distribution von Online-Vortr��gen im Internet zusammen. Ein solcher ��berblick ��ber das Themengebiet ist erforderlich f��r das Herausarbeiten eines individuellen Workflows. Hierzu werden Entscheidungskriterien f��r die Auswahl von Werkzeugen und Plattformen dargestellt und die mediendidaktischen Implikationen diskutiert.

Building an Academic Cloud for 500,000 Users

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, Germany���s 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.

Global Positioning Systems technology and its application in environmental programs /

Mode of access: Internet.

Undergraduate performance in accounting and business-based information technology

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.

A Fault-Tolerant Manipulator Robot Based on H(2), H(infinity), and Mixed H(2)/H(infinity) Markovian Controls

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.

Stable MPC for tracking with maximal domain of attraction

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.

Robust model predictive control with zone control

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.

Fixed-point DSP implementation of nonlinear H(infinity) controller for large gap electromagnetic suspension system

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.

Protec����o contra descargas atmosf��ricas: aplica����o inform��tica de identifica����o das vulnerabilidades das edifica����es e de apoio �� concep����o da protec����o

A concep����o de instala����es el��ctricas deve garantir condi����es de seguran��a para as pessoas e equipamentos. Para tal �� exigida, quer por for��a de regulamenta����o ou de normaliza����o, a instala����o de dispositivos que garantam a detec����o e a protec����o contra os defeitos mais comuns nas instala����es el��ctricas como, por exemplo, as sobreintensidades e as sobretens��es. Suscept��veis de criar sobretens��es perigosas nas instala����es el��ctricas, as descargas atmosf��ricas podem ainda causar danos estruturais elevados, o que, em algumas actividades econ��micas, torna fundamental a implementa����o de medidas de protec����o contra este fen��meno natural. A protec����o contra descargas atmosf��ricas directas consiste em identificar as vulnerabilidades das estruturas e, nesses locais, implementar dispositivos de captura, direccionamento e escoamento da descarga atmosf��rica �� terra, em condi����es de seguran��a. O presente trabalho, desenvolvido no ��mbito da disserta����o de Mestrado em Engenharia Electrot��cnica, visa desenvolver e implementar uma ferramenta computacional, baseada em programas de desenho assistido por computador (CAD) de utiliza����o corrente na ��rea de projecto de arquitectura e de engenharia, que permita, no ��mbito de normas internacionais, a an��lise e implementa����o de sistemas de protec����o em edif��cios contra descargas atmosf��ricas de uma forma r��pida e expedita. Baseado num programa CAD 3D, que permite a modeliza����o tridimensional das estruturas a proteger, a ferramenta desenvolvida tentar�� identificar as suas vulnerabilidades das estruturas ��s descargas atmosf��ricas directas, com o intuito de implementar as medidas de protec����o mais adequadas do ponto de vista t��cnico econ��mico. Prev��-se que a ferramenta resultante deste estudo, o Simulador do Modelo Electrogeom��trico (SIMODEL), possibilite aos projectistas e particularmente aos alunos das unidades curriculares na ��rea do projecto de instala����es el��ctricas da ��rea Departamental de Engenharia de Sistemas e Potencia e Automa����o (ADESPA) do ISEL, estudar e implementar sistemas de protec����o contra descargas atmosf��ricas (SPDA) baseados na normaliza����o internacional do CENELEC e da IEC, nomeadamente as normas da s��rie 62305.

Electricity markets: transmission prices methods

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; Bialek���s Tracing Method and Locational Marginal Price. A nine bus transmission network is used to illustrate the application of the tariff methods.

PCMAT Metadata Authoring Tool

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.