998 resultados para Could computing


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The vision of volunteer computing is to provide large scale computational infrastructure by using dynamic collections of donated desktop computers. There have been many works that highlighted the significant benefits of volunteer computing but little on the security and privacy threats associated with its exploitation. However, volunteer computing is vulnerable to a variety of attacks and presents numerous significant security threats to the stakeholders. This paper presents security and privacy threat taxonomy along with the security features developed to cope with such threats.

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The overall performance of a distributed system often depends on the effectiveness of its interconnection network. Thus, the study of the communication networks for distributed systems is very important, which is the focus of this paper. In particular, we address the problem of interconnection networks performance modeling for heterogeneous meta-computing systems. We consider the meta-computing system as a typical multi-cluster system. Since the heterogeneity is becoming common in such systems, we take into account network as well as cluster size heterogeneity to propose the model. To this end, we present an analytical network model and validate the model through comprehensive simulation. The results of the simulation demonstrated that the proposed model exhibits a good degree of accuracy for various system organizations and under different working conditions.

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Dedicated clusters are becoming commonly used for high performance parallel processing. Computers of a non-dedicated cluster are often idle or lightly loaded. These under utilised computers can be employed to execute parallel applications. Thus, they have to be shared by parallel and sequential applications, which could lead to the improvement of their execution performance. There is a lack of experimental study showing the behaviour and performance of executing parallel and sequential applications concurrently on a non-dedicated cluster. We present the result of an experimental study into load balancing of a mixture of parallel and sequential applications on a non-dedicated cluster.

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Computers of a non-dedicated cluster are often idle (users attend meetings, have lunch or coffee breaks) or lightly loaded (users carry out simple computations to support problem solving activities). These underutilised computers can be employed to execute parallel applications. Thus, these computers can be shared by parallel and sequential applications, which could lead to the improvement of their execution performance. However, there is a lack of experimental study showing the applications’ performance and the system utilization of executing parallel and sequential applications concurrently and concurrent execution of multiple parallel applications on a non-dedicated cluster. Here we present the result of an experimental study into load balancing based scheduling of mixtures of NAS Parallel Benchmarks and BYTE sequential applications on a very low cost non-dedicated cluster. This study showed that the proposed sharing provided performance boost as compared to the execution of the parallel load in isolation on a reduced number of computers and better cluster utilization. The results of this research were used not only to validate other researchers’ result generated by simulation but also to support our research mission of widening the use of non-dedicated clusters. Our promising results obtained could promote further research studies to convince universities, business and industry, which require a large amount of computing resources, to run parallel applications on their already owned non-dedicated clusters.

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The introduction of Web services into grids helped to address their two main obstacles to be embraced by business and industry, heterogeneity and useability. However, many problems are still open, e.g., grid reconfiguration, reliability and computing optimization. We argue here that a mechanism that could help solving these problems is Web Service migration, a part of automatic and transparent brokerage. Web service migration presents a number of new requirements not addressed in traditional process migration, being the outcome of Web services specific configuration of hosts and application servers, and availability of Web services / resources state. In this paper we report on our study into the development of a Web service migration facility focused on providing migration of services in a Service Oriented Grid environment. We present a novel approach to Web service migration, embodied in a System Management Broker, which is transparent, interoperable and flexible. We take the requirements of Web services into consideration when discovering suitable destination hosts and match services to suitable grid resources which are able to fulfil the needs of the service. We discuss a number of experiments conducted with different types of grid and Web service applications to highlight the feasibility and effectiveness of our migration facility and demonstrate how our facility significantly improves Service Oriented Grids.

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Grid users and their jobs need credentials to access grid resources and services. It is important to minimize the exposure of credentials to adversaries. A practical solution is needed that works with existing software and is easy to deploy, administer, and maintain. Thus, credential management services are the wave of the future for virtual organizations such as Grid computing. This paper describes architecture of a scalable, secure and reliable on-line credential management service called SafeBox for InterGrid computing platform. SafeBox provides InterGrid users with secure mechanism for storing one or multiple credentials and access them based on need at anytime from anywhere.

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Social software has been used to support problem-based learning activities in a wholly online information technology (IT) professional practice course at Deakin University since 2006. When the course was first delivered, the authentic learning environment was a website, with an intranet and team forums created in Drupal, the open source content management system (CMS). Although this environment was suitable, feedback from students and teaching staff highlighted areas where improvements could be made. In the second year of the course, Joomla!, the open source CMS, in combination with Simple Machines Forum (SMF), the open source online discussion community software, was used to provide the website, as well as the intranet and team forums respectively. Feedback in 2007 was more positive, suggesting that the Joomla!-SMF social software combination and the features implemented, improved the learning and teaching experience in comparison to the 2006 version of the course.

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A particle-based method for multiscale modeling of multiphase materials such as Dual Phase (DP) and Transformation Induced Plasticity (TRIP) steels has been developed. The multiscale Particle-In-Cell (PIC) method benefits from the many advantages of the FEM and mesh-free methods, and to bridge the micro and macro scales through homogenization. The conventional mesh-based modeling methods fail to give reasonable and accurate predictions for materials with complex microstructures. Alternatively in the multiscale PIC method, the Lagrangian particles moving in an Eulerian grid represent the material deformation at both the micro and macro scales. The uniaxial tension test of two phase and three-phase materials was simulated and compared with FE based simulations. The predictions using multiscale PIC method showed that accuracy of field variables could be improved by up to 7%. This can lead to more accurate forming and springback predictions for materials with important multiphase microstructural effects.

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This special issue is in response to the increasing convergence between grids and pervasive computing, while different approaches exist, challenges and opportunities are numerous in this context (Parashar and Pierson, to appear). The research papers selected for this special issue represent recent progresses in the field, including works on mobile ad-hoc grids, service and data discovery, context-aware application building and context accuracy, and communication. All of these papers not only provide novel ideas and state-of-the-art techniques in the field, but also stimulate future research in the Pervasive Grid environment.

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Blogs appear to be gaining momentum as a marketing tool which can be used by organisations for such strategies and processes as branding, managing reputation, developing customer trust and loyalty, niche marketing, gathering marketing intelligence and promoting their online presence. There has been limited academic research in this area, and most significantly concerning the types of small and medium enterprises (SMEs) for which blogs might have potential as a marketing tool. In an attempt to address the knowledge gap, this paper presents a future research agenda (in the form of research questions) which can guide the eBusiness research community in conducting much needed studies in this area. This paper is particularly novel in that it aims to demonstrate how the heterogeneity of SMEs and their specific business uses of eBusiness technology such as blogs can form the central plank of a future research agenda. This is important because the existing eBusiness literature tends to treat eBusiness collectively rather than focusing on the specific business uses of different eBusiness technologies, and to treat SMEs as a homogeneous group. The paper concludes with a discussion of how this research agenda can form the basis of studies which use a range of different research methods, and how this "big picture" agenda approach might help the eBusiness research community build theory which better explains SME adoption and use of eBusiness.

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Many intervention programmes to encourage greater female participation in computer education and careers have been conducted in the last twenty years. These intervention programmes take considerable time, effort and money to design and implement. If success were to be measured by an increase in the percentage of female students undertaking computing courses then these programmes would have to be considered a failure. This paper describes a research project which examined fourteen intervention programmes in detail. From the perspective of the programme champions each of the intervention programmes was considered successful, even when this success was restricted to specific areas or limited to small groups of individuals. Formal evaluation appeared to have been an afterthought rather than a priority of many of the programme champions. Some programmes appeared to be less effective due to the lack of targeted and clear goals or predetermined evaluation criteria. It is recommended that during the initial planning phase for intervention programmes a clear objective is to consider what a successful programme would look like and what the evaluation criteria would be. Further work is needed to understand how intervention programmes can be better designed and evaluated so that their impact and success can be expanded.

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Participation in post-compulsory computing education has declined over recent years, both in the senior years of secondary school and at university. This trend has been observed in most developed countries, despite reported and projected skills shortages in Information Technology (IT) industries. Within the computing education enrollment mix, girls and women continue to be under-represented and recent years have seen female participation fall even more rapidly than that of males. This article reports on findings of an Australian study which explored secondary school students’ beliefs about and attitudes towards computing education and careers in IT. Factors that might discourage girls in particular from pursuing post-compulsory computing education and careers are discussed, along with broader implications for school education in an era when information and communication technologies are an integral part of our daily lives. Findings include the persistence among both boys and girls of inaccurate and outdated views of the field of IT and low expectations of both school IT curricula and pedagogy in terms of their relevance and interest for students. Many of the issues identified as discouraging students in general from pursuing computing education appear to have a greater discouraging effect on girls, and this is compounded by stereotypical views of the field as male-dominated and unwelcoming to women and girls.