65,538 research outputs found

    Enabling Social Applications via Decentralized Social Data Management

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    An unprecedented information wealth produced by online social networks, further augmented by location/collocation data, is currently fragmented across different proprietary services. Combined, it can accurately represent the social world and enable novel socially-aware applications. We present Prometheus, a socially-aware peer-to-peer service that collects social information from multiple sources into a multigraph managed in a decentralized fashion on user-contributed nodes, and exposes it through an interface implementing non-trivial social inferences while complying with user-defined access policies. Simulations and experiments on PlanetLab with emulated application workloads show the system exhibits good end-to-end response time, low communication overhead and resilience to malicious attacks.Comment: 27 pages, single ACM column, 9 figures, accepted in Special Issue of Foundations of Social Computing, ACM Transactions on Internet Technolog

    Performance of Network and Service Monitoring Frameworks

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    The efficiency and the performance of anagement systems is becoming a hot research topic within the networks and services management community. This concern is due to the new challenges of large scale managed systems, where the management plane is integrated within the functional plane and where management activities have to carry accurate and up-to-date information. We defined a set of primary and secondary metrics to measure the performance of a management approach. Secondary metrics are derived from the primary ones and quantifies mainly the efficiency, the scalability and the impact of management activities. To validate our proposals, we have designed and developed a benchmarking platform dedicated to the measurement of the performance of a JMX manager-agent based management system. The second part of our work deals with the collection of measurement data sets from our JMX benchmarking platform. We mainly studied the effect of both load and the number of agents on the scalability, the impact of management activities on the user perceived performance of a managed server and the delays of JMX operations when carrying variables values. Our findings show that most of these delays follow a Weibull statistical distribution. We used this statistical model to study the behavior of a monitoring algorithm proposed in the literature, under heavy tail delays distribution. In this case, the view of the managed system on the manager side becomes noisy and out of date

    Recent advances on filtering and control for nonlinear stochastic complex systems with incomplete information: A survey

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    This Article is provided by the Brunel Open Access Publishing Fund - Copyright @ 2012 Hindawi PublishingSome recent advances on the filtering and control problems for nonlinear stochastic complex systems with incomplete information are surveyed. The incomplete information under consideration mainly includes missing measurements, randomly varying sensor delays, signal quantization, sensor saturations, and signal sampling. With such incomplete information, the developments on various filtering and control issues are reviewed in great detail. In particular, the addressed nonlinear stochastic complex systems are so comprehensive that they include conventional nonlinear stochastic systems, different kinds of complex networks, and a large class of sensor networks. The corresponding filtering and control technologies for such nonlinear stochastic complex systems are then discussed. Subsequently, some latest results on the filtering and control problems for the complex systems with incomplete information are given. Finally, conclusions are drawn and several possible future research directions are pointed out.This work was supported in part by the National Natural Science Foundation of China under Grant nos. 61134009, 61104125, 61028008, 61174136, 60974030, and 61074129, the Qing Lan Project of Jiangsu Province of China, the Project sponsored by SRF for ROCS of SEM of China, the Engineering and Physical Sciences Research Council EPSRC of the UK under Grant GR/S27658/01, the Royal Society of the UK, and the Alexander von Humboldt Foundation of Germany

    SCUdent Books: A University-Focused Bookselling Platform

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    As the beginning of each university semester or quarter commences, so does the rush to acquire books for classes. The search for school books is a busy and important task for many students. However, an entire slew of problems and frustrations emerge with this academic race to gather books. To begin, students have to deal with the traditional frustrations of expensive textbooks sold at the university bookstore which is especially troublesome for those on a tight budget. Additionally, required textbooks for classes may not be available at the bookstore or require restocking which can take an unknown amount of time. Because of this, students turn to cheaper, faster, and more efficient alternatives for acquiring school books including online retailers such as Amazon or Barnes and Noble. While the Internet makes book shopping appear easier, there exist issues that come with it. Students have to put in more effort ordering online, pay for extra shipping, and wait for their books to arrive. Also, online shopping for books is incredibly decentralized with no convenient platform to cater to students\u27 needs. Students must first spend time finding out which books are required for each class and then spend even more time comparing prices from multiple online retailers. In addition, once a student completes a class he or she may no longer need the book. As a result, the student has no convenient method of disposing the book and must now sell it, throw it away, or keep it. Overall, the process of acquiring books in university is disorganized, stressful, and inconvenient for students

    Analysis of priority queues with session-based arrival streams

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    In this paper, we analyze a discrete-time priority queue with session-based arrivals. We consider a user population, where each user can start and end sessions. Sessions belong to one of two classes and generate a variable number of fixed-length packets which arrive to the queue at the rate of one packet per slot. The lengths of the sessions are generally distributed. Packets of the first class have transmission priority over the packets of the other class. The model is motivated by a web server handling delay-sensitive and delay-insensitive content. By using probability generating functions, some performance measures of the queue such as the moments of the packet delays of both classes are calculated. The impact of the priority scheduling discipline and of the session nature of the arrival process is shown by some numerical examples

    DEVELOPMENT OF AN INTEGRATED ACCOUNTING SYSTEM BY RESOURCE-EVENT-AGENT APPROACH (A CASE STUDY AT KOPERASI PEGAWAI DANA PENSIUN TELKOM)

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    Koperasi Pegawai Dana Pensiun Telkom is a cooperative organization that is established by PT. Dana Pensiun Telkom. As a common business entity, financial report is required to give information to the shareholders or decision maker about organization’s financial state. Decision maker in this case is the board of directors. Based on this financial report, board of directors may decide the organization’s strategies. Financial report which has an important role in decision making process has a problem on its publishing time. This delayed financial report’s publishing time makes decision making process become hampered. This problem is caused by three factors, such as disintegrated data and application, and transaction journalizing process which is still using manual method. Resource-Event-Agent approach’s role on this research is to facilitate the modelling data process so that the data and application integration become more effective. The modelled data using Resource-Event-Agent can fulfil organization business process requirements especially for automating the transaction journalizing process. By using Resource-Event-Agent, the system that can be a solution is Integrated Accounting System. This system will integrate data, application, and automating the transaction journalizing process. On the future, Resource-Event-Agent can be used to model every data on every business activities on the organizatio
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