4,055 research outputs found

    My private cloud--granting federated access to cloud resources

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    We describe the research undertaken in the six month JISC/EPSRC funded My Private Cloud project, in which we built a demonstration cloud file storage service that allows users to login to it, by using their existing credentials from a configured trusted identity provider. Once authenticated, users are shown a set of accounts that they are the owners of, based on their identity attributes. Once users open one of their accounts, they can upload and download files to it. Not only that, but they can then grant access to their file resources to anyone else in the federated system, regardless of whether their chosen delegate has used the cloud service before or not. The system uses standard identity management protocols, attribute based access controls, and a delegation service. A set of APIs have been defined for the authentication, authorisation and delegation processes, and the software has been released as open source to the community. A public demonstration of the system is available online

    A Cloud Platform-as-a-Service for Multimedia Conferencing Service Provisioning

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    Multimedia conferencing is the real-time exchange of multimedia content between multiple parties. It is the basis of a wide range of applications (e.g., multimedia multiplayer game). Cloud-based provisioning of the conferencing services on which these applications rely will bring benefits, such as easy service provisioning and elastic scalability. However, it remains a big challenge. This paper proposes a PaaS for conferencing service provisioning. The proposed PaaS is based on a business model from the state of the art. It relies on conferencing IaaSs that, instead of VMs, offer conferencing substrates (e.g., dial-in signaling, video mixer and audio mixer). The PaaS enables composition of new conferences from substrates on the fly. This has been prototyped in this paper and, in order to evaluate it, a conferencing IaaS is also implemented. Performance measurements are also made.Comment: 6 pages, 6 figures, IEEE ISCC 201

    Overcoming Language Dichotomies: Toward Effective Program Comprehension for Mobile App Development

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    Mobile devices and platforms have become an established target for modern software developers due to performant hardware and a large and growing user base numbering in the billions. Despite their popularity, the software development process for mobile apps comes with a set of unique, domain-specific challenges rooted in program comprehension. Many of these challenges stem from developer difficulties in reasoning about different representations of a program, a phenomenon we define as a "language dichotomy". In this paper, we reflect upon the various language dichotomies that contribute to open problems in program comprehension and development for mobile apps. Furthermore, to help guide the research community towards effective solutions for these problems, we provide a roadmap of directions for future work.Comment: Invited Keynote Paper for the 26th IEEE/ACM International Conference on Program Comprehension (ICPC'18

    Measuring the Affordances of Studying in a Virtual World

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    There has been much interest at the University of Hertfordshire in the teaching and learning in virtual worlds such as Second Life. The School of Computer Science has established a virtual campus within this system where a broad range of learning and teaching activities take place. These include presenting textual, audio and video learning and teaching materials, delivering virtual lectures, providing simulations and group working areas. Recently there has been a great deal of controversy over such initiatives, for example at my own university lecturers are divided as to the efficacy of such an approach. Some see the initiative as an interesting addition to the range of teaching and learning strategies available, likely to motivate learners. Others see it as a trivial attempt to jump on the latest band wagon, with little pedagogical benefit or justification. My own past research in this area, over several years has related to an estimation of the cognitive load imposed by desktop virtual environments and how this affected learning. Several important variables have been identified in several years of research and their effects measured. In the study presented here, a group of 80 final year computer science students used the Second Life virtual environment in order to support their practical project work. Groups of four learners used the university virtual campus especially modified for this purpose to hold meetings and to manage their software development projects. This study reports on how the group areas were established and used by the learners, the types of activities that took place and the effectiveness of the approach in this context. Quantitative and qualitative research was undertaken and it was found that there were benefits to be had by the use of such virtual environments. Recommendations are made as to the affordances of the Second Life virtual environment for teaching and learning in this context and also discussed are the potential problems inherent in this initiative related to individual differences and the cognitive burden imposed on learners.Peer reviewe

    AKARI-CAS --- Online Service for AKARI All-Sky Catalogues

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    The AKARI All-Sky Catalogues are an important infrared astronomical database for next-generation astronomy that take over the IRAS catalog. We have developed an online service, AKARI Catalogue Archive Server (AKARI-CAS), for astronomers. The service includes useful and attractive search tools and visual tools. One of the new features of AKARI-CAS is cached SIMBAD/NED entries, which can match AKARI catalogs with other catalogs stored in SIMBAD or NED. To allow advanced queries to the databases, direct input of SQL is also supported. In those queries, fast dynamic cross-identification between registered catalogs is a remarkable feature. In addition, multiwavelength quick-look images are displayed in the visualization tools, which will increase the value of the service. In the construction of our service, we considered a wide variety of astronomers' requirements. As a result of our discussion, we concluded that supporting users' SQL submissions is the best solution for the requirements. Therefore, we implemented an RDBMS layer so that it covered important facilities including the whole processing of tables. We found that PostgreSQL is the best open-source RDBMS products for such purpose, and we wrote codes for both simple and advanced searches into the SQL stored functions. To implement such stored functions for fast radial search and cross-identification with minimum cost, we applied a simple technique that is not based on dividing celestial sphere such as HTM or HEALPix. In contrast, the Web application layer became compact, and was written in simple procedural PHP codes. In total, our system realizes cost-effective maintenance and enhancements.Comment: Yamauchi, C. et al. 2011, PASP..123..852

    OFF-PROCESS GUI RENDERING

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    An application may offload rendering of a graphical user interface (GUI) to an underlying operating system executing at a head unit (e.g., an infotainment system) of a vehicle (e.g., automobile, motorcycle, a bus, a recreational vehicle (RV), a semi-trailer truck, a tractor or other type of farm equipment, a train, a plane, a helicopter, etc.) or a computing device (e.g., a cellular phone, a smartphone, a desktop computer, a laptop computer, a tablet computer, a portable gaming device, a watch, etc.). The application may invoke functions of an application library that allow the application to generate GUI metadata including a GUI template (e.g., that specifies a predetermined layout) and content for populating the GUI template. The operating system, which may expose an interface (e.g., defined by the application library) for interacting with a display of the head unit or some other display in communication with the head unit, may receive, from the application, the GUI metadata and a token identifying the application. The operating system may then use the GUI metadata and the token to render a corresponding GUI for the application. In this way, the OS may render GUIs for applications in accordance with GUI templates, enabling a consistent look and feel that may, as one example, satisfy safety guidelines
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