934 resultados para Operating Systems


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The primary objective of this study was to verify the existence of internal organization and processes influencing the decisions on adoption, choice, justification and implementation of innovative practices of scientific and technical activities undertaken in the elaborates of sugar, ethanol and energy companies of the midwest of the state of Sao Paulo. Using multivariate analysis of principal components and clusters, the variables were analyzed and the companies, classified. The taxonomy model adapted to contemporary situations described by Freeman (1975), was the 'parameter used with research information in personal interviews by semi-structured questionnaires. The investigated activities constituted of: basic research; applied research; experimental development; scientific and technical information; long-term planning. The variables analyzed were: production processes, operating systems, development of new products, projects and implementation of pilot plant for new products, development, knowledge, studies of other business segments, number of innovations, and the number of existing employees in the organizational structure for these purposes. It was concluded that the best companies with innovative attitudes are those that have incorporated into their organizational the structures, practices and techniques of scientific activities.

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Access control is a fundamental concern in any system that manages resources, e.g., operating systems, file systems, databases and communications systems. The problem we address is how to specify, enforce, and implement access control in distributed environments. This problem occurs in many applications such as management of distributed project resources, e-newspaper and payTV subscription services. Starting from an access relation between users and resources, we derive a user hierarchy, a resource hierarchy, and a unified hierarchy. The unified hierarchy is then used to specify the access relation in a way that is compact and that allows efficient queries. It is also used in cryptographic schemes that enforce the access relation. We introduce three specific cryptography based hierarchical schemes, which can effectively enforce and implement access control and are designed for distributed environments because they do not need the presence of a central authority (except perhaps for set- UP).

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In this paper we point some aspects of workers activities in offshore units in the oil industry. These units became more verticalized and have a greater number of operating systems. Our goal is to present the main difficulties that workers face in these units.

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[ES] Programa de escritorio compatible con sistemas operativos Windows 7 y Windows 8.1. El programa configura el ordenador personal del usuario de modo que la firma electrónica de la Universidad de Las Palmas de Gran Canaria funcione correctamente en los navegadores web elegidos por el usuario. Al iniciarse la aplicación, el usuario elige dichos navegadores. El programa incorpora dos modos de instalación. La primera forma es la instalación automática, todos los componentes requeridos, que no estén instalados en el equipo, se instalarán automáticamente con una mínima intervención del usuario. La segunda forma es la instalación personalizada, se muestra una lista de los componentes requeridos y el usuario puede instalar de forma individual cada uno de éstos, si no están ya instalados. El programa también puede desinstalar los cambios realizados en el equipo, también incorpora dos formas de realizar esta operación. De forma automática, todos los componentes instalados por el programa serán desinstalados con una mínima intervención del usuario. De forma personalizada, el usuario podrá elegir el componente que se desinstala de forma individual. Siempre teniendo en cuenta que los cambios que se deshacen, son cambios realizados por el propio configurador. El programa también es capaz de analizar si un equipo cumple o no los requerimientos para que funcione correctamente la firma electrónica en su ordenador. Para analizar un equipo no se instala ningún componente. Se requiere acceso a Internet para usar este programa ya que se descargan diferentes archivos desde el servidor de la Universidad de Las Palmas de Gran Canaria.

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Máster Universitario en Sistemas Inteligentes y Aplicaciones Numéricas en Ingeniería (SIANI)

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Skype is one of the well-known applications that has guided the evolution of real-time video streaming and has become one of the most used software in everyday life. It provides VoIP audio/video calls as well as messaging chat and file transfer. Many versions are available covering all the principal operating systems like Windows, Macintosh and Linux but also mobile systems. Voice quality decreed Skype success since its birth in 2003 and peer-to-peer architecture has allowed worldwide diffusion. After video call introduction in 2006 Skype became a complete solution to communicate between two or more people. As a primarily video conferencing application, Skype assumes certain characteristics of the delivered video to optimize its perceived quality. However in the last years, and with the recent release of SkypeKit1, many new Skype video-enabled devices came out especially in the mobile world. This forced a change to the traditional recording, streaming and receiving settings allowing for a wide range of network and content dynamics. Video calls are not anymore based on static ‘chatting’ but mobile devices have opened new possibilities and can be used in several scenarios. For instance, lecture streaming or one-to-one mobile video conferences exhibit more dynamics as both caller and callee might be on move. Most of these cases are different from “head&shoulder” only content. Therefore, Skype needs to optimize its video streaming engine to cover more video types. Heterogeneous connections require different behaviors and solutions and Skype must face with this variety to maintain a certain quality independently from connection used. Part of the present work will be focused on analyzing Skype behavior depending on video content. Since Skype protocol is proprietary most of the studies so far have tried to characterize its traffic and to reverse engineer its protocol. However, questions related to the behavior of Skype, especially on quality as perceived by users, remain unanswered. We will study Skype video codecs capabilities and video quality assessment. Another motivation of our work is the design of a mechanism that estimates the perceived cost of network conditions on Skype video delivery. To this extent we will try to assess in an objective way the impact of network impairments on the perceived quality of a Skype video call. Traditional video streaming schemes lack the necessary flexibility and adaptivity that Skype tries to achieve at the edge of a network. Our contribution will lye on a testbed and consequent objective video quality analysis that we will carry out on input videos. We will stream raw video files with Skype via an impaired channel and then we will record it at the receiver side to analyze with objective quality of experience metrics.

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Lo sviluppo hardware nel campo della robotica ha raggiunto negli ultimi anni livelli impressionanti ed è in continua crescita, e di pari passo si è espansa l’eterogeneità delle forme che può assumere, dalle tipologie basate su movimento a terra ai droni volanti, fino a forme più sofisticate di robot umanoidi che cercano di emularne il comportamento. Se da un lato ora possiamo disporre di hardware sempre più potente ed efficiente a costi sempre minori, dall’altro programmare il comportamento che un robot deve tenere nelle svariate circostanze in cui può imbattersi, nel poter portare a compimento il proprio obbiettivo, risulta essere sempre più complesso. Dopo una breve introduzione alla robotica e alle difficoltà che deve affrontare e una panoramica sui robot, cosa siano e come siano strutturati, fulcro della tesi sarà l’esposizione delle caratteristiche principali di ROS, Robot Operating System, come piattaforma di sviluppo software nel campo della robotica, e si concluderà con un semplice caso di studio in cui ne verrà messo in mostra concretamente l’utilizzo.

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This project addresses the unreliability of operating system code, in particular in device drivers. Device driver software is the interface between the operating system and the device's hardware. Device drivers are written in low level code, making them difficult to understand. Almost all device drivers are written in the programming language C which allows for direct manipulation of memory. Due to the complexity of manual movement of data, most mistakes in operating systems occur in device driver code. The programming language Clay can be used to check device driver code at compile-time. Clay does most of its error checking statically to minimize the overhead of run-time checks in order to stay competitive with C's performance time. The Clay compiler can detect a lot more types of errors than the C compiler like buffer overflows, kernel stack overflows, NULL pointer uses, freed memory uses, and aliasing errors. Clay code that successfully compiles is guaranteed to run without failing on errors that Clay can detect. Even though C is unsafe, currently most device drivers are written in it. Not only are device drivers the part of the operating system most likely to fail, they also are the largest part of the operating system. As rewriting every existing device driver in Clay by hand would be impractical, this thesis is part of a project to automate translation of existing drivers from C to Clay. Although C and Clay both allow low level manipulation of data and fill the same niche for developing low level code, they have different syntax, type systems, and paradigms. This paper explores how C can be translated into Clay. It identifies what part of C device drivers cannot be translated into Clay and what information drivers in Clay will require that C cannot provide. It also explains how these translations will occur by explaining how each C structure is represented in the compiler and how these structures are changed to represent a Clay structure.

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Virtualization has become a common abstraction layer in modern data centers. By multiplexing hardware resources into multiple virtual machines (VMs) and thus enabling several operating systems to run on the same physical platform simultaneously, it can effectively reduce power consumption and building size or improve security by isolating VMs. In a virtualized system, memory resource management plays a critical role in achieving high resource utilization and performance. Insufficient memory allocation to a VM will degrade its performance dramatically. On the contrary, over-allocation causes waste of memory resources. Meanwhile, a VM’s memory demand may vary significantly. As a result, effective memory resource management calls for a dynamic memory balancer, which, ideally, can adjust memory allocation in a timely manner for each VM based on their current memory demand and thus achieve the best memory utilization and the optimal overall performance. In order to estimate the memory demand of each VM and to arbitrate possible memory resource contention, a widely proposed approach is to construct an LRU-based miss ratio curve (MRC), which provides not only the current working set size (WSS) but also the correlation between performance and the target memory allocation size. Unfortunately, the cost of constructing an MRC is nontrivial. In this dissertation, we first present a low overhead LRU-based memory demand tracking scheme, which includes three orthogonal optimizations: AVL-based LRU organization, dynamic hot set sizing and intermittent memory tracking. Our evaluation results show that, for the whole SPEC CPU 2006 benchmark suite, after applying the three optimizing techniques, the mean overhead of MRC construction is lowered from 173% to only 2%. Based on current WSS, we then predict its trend in the near future and take different strategies for different prediction results. When there is a sufficient amount of physical memory on the host, it locally balances its memory resource for the VMs. Once the local memory resource is insufficient and the memory pressure is predicted to sustain for a sufficiently long time, a relatively expensive solution, VM live migration, is used to move one or more VMs from the hot host to other host(s). Finally, for transient memory pressure, a remote cache is used to alleviate the temporary performance penalty. Our experimental results show that this design achieves 49% center-wide speedup.

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„Open source and European antitrust laws: An analysis of copyleft and the prohibition of software license fees on the basis of art. 101 TFEU and the block exemptions“ Open source software and open source licenses (like the GNU GPL) are not only relevant for computer nerds or activists – they are already business. They are for example the fundament of LINUX, the only real rival of MICROSOFT’s WINDOWS-line in the field of operating systems for IBM PC compatibles. Art. 101 TFEU (like the identical predecessor art. 81 TEC) as part of the EU antitrust laws prohibits contract terms like price fixing and some forms of technology control. Are copyleft – the „viral effect“, the „cancer“ – and the interdiction of software license fees in the cross hairs of this legal rule? On the other side the European Union has since 2004 a new Technology Transfer Block Exemption with software license agreements for the first time in its scope: a safe harbour and a dry place under a umbrella for open source software? After the introduction (A) with a description of open source software the following text analyses the system of the European Unions competition law respectivley antitrust law and the requirements of the block exemptions (B). Starting point of antitrust analysis are undertakings – but who are the untertakings (C) in the field of widespread, independent developers as part of the „bazar organization“? To see how much open source has to fear from the law of the European Union, at the end the anti competitive and pro competitive effects of open source are totalized within the legal framework (D). The conclusion (E) shows: not nothing, but not much.

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Multivariate Methoden stellen ein wesentliches Instrumentarium zur Datenanalyse in der Ökologie dar. Sie werden in der Ökologie häufig eingesetzt und sind seit langem Gegenstand der Lehre in der Abteilung Geobotanik der Universität Freiburg. In den letzten Jahren wurde als Werkzeug das Programm R eingeführt. R ist ein frei verfügbares, kommandozeilenorientiertes Statistikprogramm, das für eine Reihe von Betriebssystemen angeboten wird (R-Development Core-Team 2007). Das Programm befindet sich in rascher Entwicklung (derzeit Version 2.10) und wird zunehmend auch von Ökologen eingesetzt. Bislang existiert kein deutschsprachiges Lehrbuch zur Anwendung multivariater Methoden mit R. Mit MultiStaR wird versucht, diese Lücke zu schließen und den Studierenden Lernmaterialien an die Hand zu geben, die Übungen mit dem eigentlichen Analysewerkzeug mit einschließen.

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Mit der Idee eines generischen, an vielfältige Hochschulanforderungen anpassbaren Studierenden-App-Frameworks haben sich innerhalb des Arbeitskreises Web der ZKI ca. 30 Hochschulen zu einem Entwicklungsverbund zusammengefunden. Ziel ist es, an den beteiligten Einrichtungen eine umfassende Zusammenstellung aller elektronischen Studienservices zu evaluieren, übergreifende Daten- und Metadatenmodelle für die Beschreibung dieser Dienste zu erstellen und Schnittstellen zu den gängigen Campusmanagementsystemen sowie zu Infrastrukturen der elektronischen Lehre (LMS, Druckdienste, elektronischen Katalogen usw.) zu entwickeln. In einem abschließenden Schritt werden auf dieser Middleware aufsetzende Studienmanagement-Apps für Studierende erstellt, die die verschiedenen Daten- und Kommunikationsströme der standardisierten Dienste und Kommunikationskanäle bündeln und in eine für den Studierenden leicht zu durchschauende, navigationsfreundliche Aufbereitung kanalisiert. Mit der Konzeption eines dezentralen, über eine Vielzahl von Hochschulen verteilten Entwicklungsprojektes unter einer zentralen Projektleitung wird sichergestellt, dass redundante Entwicklungen vermieden, bundesweit standardisierte Serviceangebote angeboten und Wissenstransferprozesse zwischen einer Vielzahl von Hochschulen zur Nutzung mobiler Devices (Smartphones, Tablets und entsprechende Apps) angeregt werden können. Die Unterstützung der Realisierung klarer Schnittstellenspezifikationen zu Campusmanagementsystemen durch deren Anbieter kann durch diese breite Interessensgemeinschaft ebenfalls gestärkt werden. Weiterhin zentraler Planungsinhalt ist ein Angebot für den App-Nutzer zum Aufbau eines datenschutzrechtlich integeren, persönlichen E-Portfolios. Details finden sich im Kapitel Projektziele weiter unten.

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The software PanXML is a tool to create XML files needed for DOI registration at the German National Library of Science and Technology (TIB). PanXML is distributed as freeware for the operating systems Microsoft Windows, Apple OS X and Linux. An XML file created by PanXML is based on the XSD file article-doi_v3.2.xsd. Further schemas may be added on request.

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The software Multibeam Converter is a tool to convert files or folders of files (ascii/tab-separated data files with or without metaheader), downloaded from PANGAEA via the search engine or the data warehouse to the ODV import format, e.g. for visualization or further processing. MultibeamConverter is distributed as freeware for the operating systems Microsoft Windows, Apple OS X and Linux.

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LatLongConverter converts positions from geodetic system to Gauss-Krüger or UTM coordinates. This program is distributed as freeware for the operating systems Microsoft Windows, Apple OS X and Linux.