A significant disadvantage of fully homomorphic encryption is the long periods of time needed to process encrypted data, due to its complex and CPU-intensive arithmetic techniques. In this paper, a communication proto...
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ISBN:
(纸本)9781538637906
A significant disadvantage of fully homomorphic encryption is the long periods of time needed to process encrypted data, due to its complex and CPU-intensive arithmetic techniques. In this paper, a communication protocol is developed to ensure authenticity, integrity and privacy of measurement data across a distributed measuring system. the fully homomorphic encryption library LibScarab was extended by integer arithmetics, comparisons, decisions and multithreading to secure data processing. Furthermore, it enhances 32 and 64-bit arithmetic operations, improving them by a higher factor. this extension is integrated into a cloud computing architecture establishing privacy by design. the resulting parallelized algorithm solved the time constraint issues for smart meter gateway tariffs. Several tests were performed, fulfilling tariff specifications, where preserving privacy of accumulated data was necessary. It was concluded that this extension of the fully homomorphic encryption library meets the requirements of real world applications.
Graph problems are finding increasing applications in high performance computing disciplines. Although many regular problems can be solved efficiently in parallel, obtaining efficient implementations for irregular gra...
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ISBN:
(纸本)9783540747413
Graph problems are finding increasing applications in high performance computing disciplines. Although many regular problems can be solved efficiently in parallel, obtaining efficient implementations for irregular graph problems remains a challenge. We propose techniques for designing and implementing efficient parallel algorithms for graph problems on symmetric multiprocessors and chip multiprocessors with a case study of parallel tree and connectivity algorithms. the problems we study represent a wide range of irregular problems that have fast theoretic parallel algorithms but no known efficient parallel implementations that achieve speedup without serious restricting assumptions about the inputs. We believe our techniques will be of practical impact in solving large-scale graph problems.
the concept of XML views is proposed to integrate heterogeneous data sources in XML, and a global XML view can represent the distributed heterogeneous data sources as single XML document. XQuery is one of the standard...
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ISBN:
(纸本)9783540747413
the concept of XML views is proposed to integrate heterogeneous data sources in XML, and a global XML view can represent the distributed heterogeneous data sources as single XML document. XQuery is one of the standard query languages for searching XML data. How to process efficiently of global XQuery queries, which are written under a global XML view, emerges as a new research topic. Popular techniques of distributed query processing are based on decomposition, and static decomposition is one of the processing techniques for the traditional query language. However, XQuery has a complex syntax such as FOR clauses that are not supported by other query languages, and its structural complexity causes some considerations for the decomposition of global XQuery queries. In this paper, we propose a method to decompose a global XQuery query into local XQuery queries and to construct the result of the global XQuery query from the results of the local XQuery queries.
Congestion Control is a necessary tool in Transaction processing Systems (TPS), to avoid excessive degradation of response times. But it should have an autonomic behavior, adapting automatically to request characteris...
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ISBN:
(纸本)9783540747413
Congestion Control is a necessary tool in Transaction processing Systems (TPS), to avoid excessive degradation of response times. But it should have an autonomic behavior, adapting automatically to request characteristics to deliver the best possible service. Given that every request has either explicit or implicit deadlines (maximum acceptable response times), we analyze strategies that target request deadlines and throughput. these include maximum throughput seeker strategies, strategies using feedback control on miss rate and an additional proposal for preventive control of miss rates and throughput. Another goal of our proposal is for the control to be external and it should not rely on analytic models for control (because the predictions may be erroneous due to physical system issues). We analyze and compare alternative designs for the control including our own proposals and related ones. Our experiments consider both varied request inter-arrival and duration distributions and a real transaction processing benchmark.
Obsolete hardware can be effectively reused through intelligent software optimization, which is possible only when source code is available. Virtual Distro Dispatcher (VDD) is a system that produces virtual machines o...
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ISBN:
(纸本)9783540747413
Obsolete hardware can be effectively reused through intelligent software optimization, which is possible only when source code is available. Virtual Distro Dispatcher (VDD) is a system that produces virtual machines on a central server and projects them on a number of costless physical terminals. VDD is the result of an extreme software optimisation based on virtualization and terminal servers. VDD creates and projects Linux distros that are completely customizable and different from each other. they are virtual desktop machines that can be used for testing or developing and are completely controllable directly from each terminal. Memory consumption has been strongly reduced without sacrificing performances. Test results are encouraging to proceed withthe research towards clustering.
the paper concerns a special architecture of dynamic shared memory processor (SMP) clusters organized at program run-time. In this architecture, designed for implementation in System on Chip technology, a new mechanis...
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ISBN:
(纸本)9783540747666
the paper concerns a special architecture of dynamic shared memory processor (SMP) clusters organized at program run-time. In this architecture, designed for implementation in System on Chip technology, a new mechanism of the communication on the fly is provided. It is a combination of dynamic processor switching between SNIP clusters and parallel data reads on the fly. this mechanism enables direct communication between processor data caches and eliminates many data transactions on memory busses. the paper presents the principles of the new architecture and evaluates its efficiency for execution of matrix multiplication with recursive matrix decomposition into quarters. the evaluation is done by simulation experiments with symbolic execution of parallel program graphs with different parallelization grain.
Wireless sensor networks which are envisioned to consist of many simple processing, storage, sensing, and communication capabilities are believed to open the doors to a plethora of new applications. Efficient robust d...
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ISBN:
(纸本)9783540747666
Wireless sensor networks which are envisioned to consist of many simple processing, storage, sensing, and communication capabilities are believed to open the doors to a plethora of new applications. Efficient robust data aggregation is a key feature in information processing in wireless sensor environments, especially in the presence of faulty sensor nodes which arise due to harsh environments or manufacturing reasons. these conditions highly affect the quality of gathering data in different locations and times. In this paper we propose a distributed localized method for detecting regions that are susceptible to message loss above a given threshold, and then based on this method we suggest an algorithm for clustering nodes in that region which proportionally adapts based on message loss. Simulation experiments confirm the validity of the proposed algorithm with a high degree of accuracy.
Many essential fundamental services for networked distributed systems (ad hoc, wireless or sensor) involve maintaining a global predicate over the entire network (defined by some invariance relation on the global stat...
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ISBN:
(纸本)9783540747413
Many essential fundamental services for networked distributed systems (ad hoc, wireless or sensor) involve maintaining a global predicate over the entire network (defined by some invariance relation on the global state of the network) by using local knowledge at each of the participating nodes. the participating nodes can no longer keep track of even a small fraction of the knowledge about the global network due to limited storage. We need a new paradigm of localized distributed algorithms, where a node takes simple actions based on local knowledge of only its immediate neighbors and yet the system achieves a global objective. Self-stabilization is a relatively new paradigm for designing such localized distributed algorithms for networks;it is an optimistic way of looking at system fault tolerance and scalable coordination;it provides a cost effective built-in safeguard against transient failures that might corrupt data in a distributed system. We introduce self-stabilizing protocol design withthe example of a total dominating set in a network graph and discuss some open problems.
Traditional parallel schedulers running on cluster supercomputers support only static scheduling, where the number of processors allocated to an application remains fixed throughout the execution of the job. this resu...
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ISBN:
(纸本)9783540747413
Traditional parallel schedulers running on cluster supercomputers support only static scheduling, where the number of processors allocated to an application remains fixed throughout the execution of the job. this results in under-utilization of idle system resources thereby decreasing overall system throughput. In our research, we have developed a prototype framework called ReSHAPE, which supports dynamic resizing of parallel NIPI applications executing on distributed memory platforms. the resizing library in ReSHAPE includes support for releasing and acquiring processors and efficiently redistributing application state to a new set of processors. In this paper, we derive an algorithm for redistributing two-dimensional block-cyclic arrays from P to Q processors, organized as 2-D processor grids. the algorithm ensures a contention-free communication schedule for data redistribution if P-r <= Q(r) and P-c <= Q(c). In other cases, the algorithm implements circular row and column shifts on the communication schedule to minimize node contention.
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