55 research outputs found

    Privacy Protection on Cloud Computing

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    Cloud is becoming the most popular computing infrastructure because it can attract more and more traditional companies due to flexibility and cost-effectiveness. However, privacy concern is the major issue that prevents users from deploying on public clouds. My research focuses on protecting user\u27s privacy in cloud computing. I will present a hardware-based and a migration-based approach to protect user\u27s privacy. The root cause of the privacy problem is current cloud privilege design gives too much power to cloud providers. Once the control virtual machine (installed by cloud providers) is compromised, external adversaries will breach users’ privacy. Malicious cloud administrators are also possible to disclose user’s privacy by abusing the privilege of cloud providers. Thus, I develop two cloud architectures – MyCloud and MyCloud SEP to protect user’s privacy based on hardware virtualization technology. I eliminate the privilege of cloud providers by moving the control virtual machine (control VM) to the processor’s non-root mode and only keep the privacy protection and performance crucial components in the Trust Computing Base (TCB). In addition, the new cloud platform can provide rich functionalities on resource management and allocation without greatly increasing the TCB size. Besides the attacks to control VM, many external adversaries will compromise one guest VM or directly install a malicious guest VM, then target other legitimate guest VMs based on the connections. Thus, collocating with vulnerable virtual machines, or ”bad neighbors” on the same physical server introduces additional security risks. I develop a migration-based scenario that quantifies the security risk of each VM and generates virtual machine placement to minimize the security risks considering the connections among virtual machines. According to the experiment, our approach can improve the survivability of most VMs

    ICASE

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    This report summarizes research conducted at the Institute for Computer Applications in Science and Engineering in the areas of (1) applied and numerical mathematics, including numerical analysis and algorithm development; (2) theoretical and computational research in fluid mechanics in selected areas of interest, including acoustics and combustion; (3) experimental research in transition and turbulence and aerodynamics involving Langley facilities and scientists; and (4) computer science

    Research and technology, 1986

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    The mission of the NASA Langley Research Center is to increase the knowledge and capability of the United States in a full range of aeronautics disciplines and in selected space disciplines. This mission will be accomplished by: performing innovative research relevant to national needs and Agency goals; transferring technology to users in a timely manner; and providing development support to other United States Government agencies, industry, and the NASA centers. This report contains highlights of the major accomplishments and applications made during the past year. The highlights illustrate both the broad range of the research and technology activities at the NASA Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research

    NASA Tech Briefs, January 1992

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    Topics include: New Product Ideas; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery/Automation; Fabrication; Mathematics and Information Sciences; Life Sciences

    ISCR Annual Report: Fical Year 2004

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    Infrared astronomical satellite (IRAS) catalogs and atlases. Volume 1: Explanatory supplement

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    The Infrared Astronomical Satellite (IRAS) was launched on January 26, 1983. During its 300-day mission, IRAS surveyed over 96 pct of the celestial sphere at four infrared wavelengths, centered approximately at 12, 25, 60, and 100 microns. Volume 1 describes the instrument, the mission, and data reduction

    Qualifying 4D Deforming Surfaces by Registered Differential Features

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    Institute of Perception, Action and BehaviourRecent advances in 4D data acquisition systems in the field of Computer Vision have opened up many exciting new possibilities for the interpretation of complex moving surfaces. However, a fundamental problem is that this has also led to a huge increase in the volume of data to be handled. Attempting to make sense of this wealth of information is then a core issue to be addressed if such data can be applied to more complex tasks. Similar problems have been historically encountered in the analysis of 3D static surfaces, leading to the extraction of higher-level features based on analysis of the differential geometry.Our central hypothesis is that there exists a compact set of similarly useful descriptors for the analysis of dynamic 4D surfaces. The primary advantages in considering localised changes are that they provide a naturally useful set of invariant characteristics. We seek a constrained set of terms - a vocabulary - for describing all types of deformation. By using this, we show how to describe what the surface is doing more effectively; and thereby enable better characterisation, and consequently more effective visualisation and comparison.This thesis investigates this claim. We adopt a bottom-up approach of the problem, in which we acquire raw data from a newly constructed commercial 4D data capture system developed by our industrial partners. A crucial first step resolves the temporal non-linear registration between instances of the captured surface. We employ a combined optical/range flow to guide a conformation over a sequence. By extending the use of aligned colour information alongside the depth data we improve this estimation in the case of local surface motion ambiguities. By employing a KLT/thin-plate-spline method we also seek to preserve global deformation for regions with no estimate.We then extend aspects of differential geometry theory for existing static surface analysis to the temporal domain. Our initial formulation considers the possible intrinsic transitions from the set of shapes defined by the variations in the magnitudes of the principal curvatures. This gives rise to a total of 15 basic types of deformation. The change in the combined magnitudes also gives an indication of the extent of change. We then extend this to surface characteristics associated with expanding, rotating and shearing; to derive a full set of differential features.Our experimental results include qualitative assessment of deformations for short episodic registered sequences of both synthetic and real data. The higher-level distinctions extracted are furthermore a useful first step for parsimonious feature extraction, which we then proceed to demonstrate can be used as a basis for further analysis. We ultimately evaluate this approach by considering shape transition features occurring within the human face, and the applicability for identification and expression analysis tasks

    The 1991 Marshall Space Flight Center research and technology

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    A compilation of 194 articles addressing research and technology activities at the Marshall Space Flight Center (MSFC) is given. Activities are divided into three major areas: advanced studies addressing transportation systems, space systems, and space science activities conducted primarily in the Program Development Directorate; research tasks carried out in the Space Science Laboratory; and technology programs hosted by a wide array of organizations at the Center. The theme for this year's report is 'Building for the Future'

    Artistic Path Space Editing of Physically Based Light Transport

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    Die Erzeugung realistischer Bilder ist ein wichtiges Ziel der Computergrafik, mit Anwendungen u.a. in der Spielfilmindustrie, Architektur und Medizin. Die physikalisch basierte Bildsynthese, welche in letzter Zeit anwendungsĂŒbergreifend weiten Anklang findet, bedient sich der numerischen Simulation des Lichttransports entlang durch die geometrische Optik vorgegebener Ausbreitungspfade; ein Modell, welches fĂŒr ĂŒbliche Szenen ausreicht, Photorealismus zu erzielen. Insgesamt gesehen ist heute das computergestĂŒtzte Verfassen von Bildern und Animationen mit wohlgestalteter und theoretisch fundierter Schattierung stark vereinfacht. Allerdings ist bei der praktischen Umsetzung auch die RĂŒcksichtnahme auf Details wie die Struktur des AusgabegerĂ€ts wichtig und z.B. das Teilproblem der effizienten physikalisch basierten Bildsynthese in partizipierenden Medien ist noch weit davon entfernt, als gelöst zu gelten. Weiterhin ist die Bildsynthese als Teil eines weiteren Kontextes zu sehen: der effektiven Kommunikation von Ideen und Informationen. Seien es nun Form und Funktion eines GebĂ€udes, die medizinische Visualisierung einer Computertomografie oder aber die Stimmung einer Filmsequenz -- Botschaften in Form digitaler Bilder sind heutzutage omniprĂ€sent. Leider hat die Verbreitung der -- auf Simulation ausgelegten -- Methodik der physikalisch basierten Bildsynthese generell zu einem Verlust intuitiver, feingestalteter und lokaler kĂŒnstlerischer Kontrolle des finalen Bildinhalts gefĂŒhrt, welche in vorherigen, weniger strikten Paradigmen vorhanden war. Die BeitrĂ€ge dieser Dissertation decken unterschiedliche Aspekte der Bildsynthese ab. Dies sind zunĂ€chst einmal die grundlegende Subpixel-Bildsynthese sowie effiziente Bildsyntheseverfahren fĂŒr partizipierende Medien. Im Mittelpunkt der Arbeit stehen jedoch AnsĂ€tze zum effektiven visuellen VerstĂ€ndnis der Lichtausbreitung, die eine lokale kĂŒnstlerische Einflussnahme ermöglichen und gleichzeitig auf globaler Ebene konsistente und glaubwĂŒrdige Ergebnisse erzielen. Hierbei ist die Kernidee, Visualisierung und Bearbeitung des Lichts direkt im alle möglichen Lichtpfade einschließenden "Pfadraum" durchzufĂŒhren. Dies steht im Gegensatz zu Verfahren nach Stand der Forschung, die entweder im Bildraum arbeiten oder auf bestimmte, isolierte Beleuchtungseffekte wie perfekte Spiegelungen, Schatten oder Kaustiken zugeschnitten sind. Die Erprobung der vorgestellten Verfahren hat gezeigt, dass mit ihnen real existierende Probleme der Bilderzeugung fĂŒr Filmproduktionen gelöst werden können
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