112,475 research outputs found

    Creating architecture for a digital information system leveraging virtual environments

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    Abstract. The topic of the thesis was the creation of a proof of concept digital information system, which utilizes virtual environments. The focus was finding a working design, which can then be expanded upon. The research was conducted using design science research, by creating the information system as the artifact. The research was conducted for Nokia Networks in Oulu, Finland; in this document referred to as “the target organization”. An information system is a collection of distributed computing components, which come together to create value for an organization. Information system architecture is generally derived from enterprise architecture, and consists of a data-, technical- and application architectures. Data architecture outlines the data that the system uses, and the policies related to its usage, manipulation and storage. Technical architecture relates to various technological areas, such as networking and protocols, as well as any environmental factors. The application architecture consists of deconstructing the applications that are used in the operations of the information system. Virtual reality is an experience, where the concepts of presence, autonomy and interaction come together to create an immersive alternative to a regular display-based computer environment. The most typical form of virtual reality consists of a headmounted device, controllers and movement-tracking base stations. The user’s head- and body movement can be tracked, which changes their position in the virtual environment. The proof-of-concept information system architecture used a multi-server -based solution, where one central physical server hosted multiple virtual servers. The system consisted of a website, which was the knowledge-center and where a client software could be downloaded. The client software was the authorization portal, which determined the virtual environments that were available to the user. The virtual reality application included functionalities, which enable co-operative, virtualized use of various Nokia products, in immersive environments. The system was tested in working situations, such as during exhibitions with customers. The proof-of-concept system fulfilled many of the functional requirements set for it, allowing for co-operation in the virtual reality. Additionally, a rudimentary model for access control was available in the designed system. The shortcomings of the system were related to areas such as security and scaling, which can be further developed by introducing a cloud-hosted environment to the architecture

    Building Programmable Wireless Networks: An Architectural Survey

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    In recent times, there have been a lot of efforts for improving the ossified Internet architecture in a bid to sustain unstinted growth and innovation. A major reason for the perceived architectural ossification is the lack of ability to program the network as a system. This situation has resulted partly from historical decisions in the original Internet design which emphasized decentralized network operations through co-located data and control planes on each network device. The situation for wireless networks is no different resulting in a lot of complexity and a plethora of largely incompatible wireless technologies. The emergence of "programmable wireless networks", that allow greater flexibility, ease of management and configurability, is a step in the right direction to overcome the aforementioned shortcomings of the wireless networks. In this paper, we provide a broad overview of the architectures proposed in literature for building programmable wireless networks focusing primarily on three popular techniques, i.e., software defined networks, cognitive radio networks, and virtualized networks. This survey is a self-contained tutorial on these techniques and its applications. We also discuss the opportunities and challenges in building next-generation programmable wireless networks and identify open research issues and future research directions.Comment: 19 page

    Secure Integration of Desktop Grids and Compute Clusters Based on Virtualization and Meta-Scheduling

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    Reducing the cost for business or scientific computations, is a commonly expressed goal in today’s companies. Using the available computers of local employees or the outsourcing of such computations are two obvious solutions to save money for additional hardware. Both possibilities exhibit security related disadvantages, since the deployed software and data can be copied or tampered if appropriate countermeasures are not taken. In this paper, an approach is presented to let a local desktop machines and remote cluster resources be securely combined into a singel Grid environment. Solutions to several problems in the areas of secure virtual networks, meta-scheduling and accessing cluster schedulers from desktop Grids are proposed

    System Support for Managing Invalid Bindings

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    Context-aware adaptation is a central aspect of pervasive computing applications, enabling them to adapt and perform tasks based on contextual information. One of the aspects of context-aware adaptation is reconfiguration in which bindings are created between application component and remote services in order to realize new behaviour in response to contextual information. Various research efforts provide reconfiguration support and allow the development of adaptive context-aware applications from high-level specifications, but don't consider failure conditions that might arise during execution of such applications, making bindings between application and remote services invalid. To this end, we propose and implement our design approach to reconfiguration to manage invalid bindings. The development and modification of adaptive context-aware applications is a complex task, and an issue of an invalidity of bindings further complicates development efforts. To reduce the development efforts, our approach provides an application-transparent solution where the issue of the invalidity of bindings is handled by our system, Policy-Based Contextual Reconfiguration and Adaptation (PCRA), not by an application developer. In this paper, we present and describe our approach to managing invalid bindings and compare it with other approaches to this problem. We also provide performance evaluation of our approach

    Computing in the RAIN: a reliable array of independent nodes

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    The RAIN project is a research collaboration between Caltech and NASA-JPL on distributed computing and data-storage systems for future spaceborne missions. The goal of the project is to identify and develop key building blocks for reliable distributed systems built with inexpensive off-the-shelf components. The RAIN platform consists of a heterogeneous cluster of computing and/or storage nodes connected via multiple interfaces to networks configured in fault-tolerant topologies. The RAIN software components run in conjunction with operating system services and standard network protocols. Through software-implemented fault tolerance, the system tolerates multiple node, link, and switch failures, with no single point of failure. The RAIN-technology has been transferred to Rainfinity, a start-up company focusing on creating clustered solutions for improving the performance and availability of Internet data centers. In this paper, we describe the following contributions: 1) fault-tolerant interconnect topologies and communication protocols providing consistent error reporting of link failures, 2) fault management techniques based on group membership, and 3) data storage schemes based on computationally efficient error-control codes. We present several proof-of-concept applications: a highly-available video server, a highly-available Web server, and a distributed checkpointing system. Also, we describe a commercial product, Rainwall, built with the RAIN technology
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