the skyline queries help users handle the huge amount of available data by finding a set of interesting points. As the dataset sizes are constantly increasing and skyline queries are computationally expensive, it is c...
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ISBN:
(纸本)9781538637906
the skyline queries help users handle the huge amount of available data by finding a set of interesting points. As the dataset sizes are constantly increasing and skyline queries are computationally expensive, it is critical to compute such queries by utilizing parallelism. Existing works deal exclusively withthe totally ordered attribute domains. In this paper, we present a framework, named PSLP, for parallel skyline evaluation for data with both totally and partially ordered domains. We introduce a new partial-to-order mapping scheme that guarantees the correctness of the mapping by preserving incomparability and preference with low mapping cost. We also propose a novel logical partitioning for parallelprocessing where data space are partitioned according to their incomparability and preference relationships by using a pivot point. the logical partitioning can prune away partitions that do not contain any skyline point at the partitioning processing. An extensive performance evaluation confirms the efficiency and effectiveness of the proposed approach.
Collective communication libraries are widely developed and used in scientific community to support parallel and Grid programming. On the other side they often lack in Mobile Agents systems even if message passing is ...
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ISBN:
(纸本)9783540680673
Collective communication libraries are widely developed and used in scientific community to support parallel and Grid programming. On the other side they often lack in Mobile Agents systems even if message passing is always supported to grant communication ability to the agents. Collective communication primitives can help to develop agents based parallel application. they can also benefit social ability and interactions of collaborative agents. Here we present a collective communication service implemented in the Jade agent platform. Furthermore we propose its exploitation to interface transparently heterogeneous executions instances of a scientific parallel application that runs in a distributed environment.
the discrete cosine transform (DCT) is a key step in many image and video-coding applications, and its efficient implementation has been extensively studied for software implementations and for custom VLSI. In this pa...
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the discrete cosine transform (DCT) is a key step in many image and video-coding applications, and its efficient implementation has been extensively studied for software implementations and for custom VLSI. In this paper, we discuss how the partial distributed arithmetic algorithm can be applied to the efficient implementation of the DCT in reconfigurable logic circuits which form the core of a custom computer. Early calculations show a performance improvement of about 5 times for DCT based implementations on an FPGA compared to conventional arithmetic.
Novel platforms of modular robot systems have been developed with important applications in safety, transportation and sensing domains. In such systems, modular robots are able to change their organization in order to...
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ISBN:
(纸本)9781479942930
Novel platforms of modular robot systems have been developed with important applications in safety, transportation and sensing domains. In such systems, modular robots are able to change their organization in order to obtain different shapes. the conception of distributed programs allowing the "optimal" reorganization of a set of robots into a specific shape appears as a very challenging problem. In this paper we present an original distributed meta-algorithm for micro-robots shape-shifting problem. We show that this meta-algorithm, described as a general functioning schema, presents a good framework to easily conceive distributed algorithms for shape-shifting problems. We also prove the facility to instantiate the algorithm for special target shapes and we give an adaptation of the algorithm to reach any horizontally convex form. the presented meta-algorithm presents two main advantages: first, there is no need to exact positioning of the robots and secondly, the memory storage and communication requirements are significantly reduced.
Multi-authority attribute-based encryption (ABE) is regarded as one of the most promising techniques to handle the problem of the access control of shared data because it provides fine-grained access control of encryp...
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ISBN:
(纸本)9781538637906
Multi-authority attribute-based encryption (ABE) is regarded as one of the most promising techniques to handle the problem of the access control of shared data because it provides fine-grained access control of encrypted data in cloud storge. However, most existing multi-authority ABE schemes suffer from expensive computational cost on the user side, which increases withthe complexity of access structures. In this paper, we present a novel large universe decentralized ABE scheme with outsourced encryption and decryption based on the multi-authority system for mobile cloud computing. A majority of complex and expensive computation operations are migrated to the encryption and decryption proxy server respectively, so we can minimize the computation overhead for the data users simultaneously. the theoretical analysis indicates that our scheme is correct with static security in the random oracle model. Furthermore, the analytical comparison and extensive experimental results demonstrate that our scheme is efficient.
Ransomware is one of the malicious software that is designed to prevent access to computer system until a sum of money is paid by the victim to the attacker. During the infection, the computer will either be locked, o...
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ISBN:
(纸本)9781665435741
Ransomware is one of the malicious software that is designed to prevent access to computer system until a sum of money is paid by the victim to the attacker. During the infection, the computer will either be locked, or the data will be encrypted. Ransoms are often demanded in Bitcoin, a largely anonymous Cryptocurrency. All transactions are recorded in the blockchain and verified by peer-to-peer networks. this paper investigation collects ten recent ransomware families, which use bitcoin as a payment for their ransom. In conjunction, we identified, collected and analysed Bitcoin addresses of users combining information from a clustering model and the blockchain. We used a heuristic clustering algorithm to reveal the hidden node's payment of ransomware. Finally, we demonstrated the characteristics of ransomware encryption mechanisms that include a view of the infected process and its execution, and the distinctive demands of ransom.
We investigate cryptanalytic applications comprised of many independent tasks that exhibit a stochastic runtime distribution. We compare four algorithms for executing such applications on GPUs. We demonstrate that for...
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ISBN:
(纸本)9781665435772
We investigate cryptanalytic applications comprised of many independent tasks that exhibit a stochastic runtime distribution. We compare four algorithms for executing such applications on GPUs. We demonstrate that for different distributions, problem sizes, and platforms the best strategy varies. We support our analytic results by extensive experiments on two different GPUs, from different sides of the performance spectrum: A high performance GPU (Nvidia Volta) and an energy saving system on chip (Jetson Nano).
Pattern libraries are important tools for high productivity application development. their struggle for best performance is complicated by the fact that they are used to execute user-provided code, which is not known ...
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ISBN:
(纸本)9781479942930
Pattern libraries are important tools for high productivity application development. their struggle for best performance is complicated by the fact that they are used to execute user-provided code, which is not known during their creation. this makes pattern libraries good candidate for automatic software tuning. In this paper, we deal with automatic online parameter tuning of the HyPHI hybrid pattern library for heterogeneous systems equipped withthe Intel Xeon Phi coprocessors. We propose a framework that can be used to combine a pattern library with an existing tuning library in a practical and efficient way. Our experiments show that tuning can noticeably improve the performance of the library and it introduces very little overhead.
the processing of graphs is of increasing importance in many applications, withthe size of such graphs growing rapidly. As with scientific computing, there is a growing need to understand the relationship between sys...
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ISBN:
(纸本)9781509036820
the processing of graphs is of increasing importance in many applications, withthe size of such graphs growing rapidly. As with scientific computing, there is a growing need to understand the relationship between system architectures and graph algorithms, especially as boththe scale of the system and the size of the graph increase. To date there is one such graph benchmark that has several hundred comparative reports available, namely Breadth First Search, which has over the last few years fueled new algorithms that have improved typical performance very significantly. this paper suggests an additional benchmark based on the computation of neighborhoods and Jaccard coefficients that is of both a different intrinsic complexity and can be recast in multiple ways that may be suitable for different classes of real-world applications.
As system sizes increase, the amount of time in which an application can run without experiencing a failure decreases. Exascale applications will need to address fault tolerance. In order to support algorithm-based fa...
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ISBN:
(纸本)9780769546759
As system sizes increase, the amount of time in which an application can run without experiencing a failure decreases. Exascale applications will need to address fault tolerance. In order to support algorithm-based fault tolerance, communication libraries will need to provide fault-tolerance features to the application. One important fault-tolerance operation is distributed consensus. this is used, for example, to collectively decide on a set of failed processes. this paper describes a scalable, distributed consensus algorithm that is used to support new MPI fault-tolerance features proposed by the MPI 3 Forum's fault-tolerance working group. the algorithm was implemented and evaluated on a 4,096-core Blue Gene/P. the implementation was able to perform a full-scale distributed consensus in 222 mu s and scaled logarithmically.
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