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2009 International Conference on Apperceiving Computing and Intelligence Analysis, ICACIA 2009

作者： Wang, Zheng-Fei Tang, Ai-Guo Wang, Wei Department of Computer Hunan Business College Changsha 410205 China National Key Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha 410073 China School of Computer Science Fudan University Shanghai 200433 China

ISBN: (纸本)9781424452040

There are a lot of important and sensitive data in databases, which need to be protected from attacks. To secure the data, Cryptography support is an effective mechanism. However, a tradeoff must be made between the performance and the security because encryption and decryption greatly degrade the query performance. In this paper, a framework is proposed that can quickly implement query over encrypted data based on B+ tree. When data are stored in the form of cipher, it not only stores the encrypted data themselves, but also creates a B+ tree index for the data before encrypting them. When querying the encrypted data, firstly, it locates the encrypted records related to the querying predicate based on the B+ tree index;secondly, it decrypts the encrypted records to accomplish the results. Meanwhile, it must encrypt the B+ tree itself to protect it from leaking confidential information. According to the structure of the B+ tree, it encrypts each node of the B+ tree separately. The results of experiments show that the query performance over the encrypted data decreases about 20 percent compared with the plaintext query performance, and validate the functionality and usability of our approach. ©2009 IEEE.

关键词： Cryptography

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A Comparative Study of parallel Prefix Adders in FPGA Implementation of EAC

A Comparative Study of Parallel Prefix Adders in FPGA Implem...

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Euromicro Symposium on Digital System Design

作者： Feng Liu Fariborz Fereydouni Forouzandeh Otmane Ait Mohamed Gang Chen Xiaoyu Song Qingping Tan Parallel Distributed Processing National Laboratory Hunan China National Lab of Parallel Distributed processing Hunan China ECE department Concordia University Montreal Quebec Canada Lingcore Lab Portland OR USA ECE department Portland State University Portland OR USA

Several regular parallel trees have been proposed over the years to optimize logic depth, area, fan-out and interconnect count for logic circuits. In this paper, we propose a comparative study of different parallel prefix trees used in the design of a new end-around carry (EAC) adder targeting FPGA technology. This new adder is based on the fast 128-bit binary floating-point EAC adder which has been implemented in the IBM POWER6 microprocessor's fused multiply-add unit. The parallel prefix tree implemented on the IBM's EAC adder is a Kogge-Stone tree which has been chosen for its high performance and its low power consumption. Our comparative study highlights the main performance differences among fourteen different architecture configurations when targeting an FPGA EAC adder design. We focus on the area requirements and the critical path delay of these designs. Our experimental results show that there is one architecture configuration with the lower area requirement and the higher performance.

关键词： Field programmable gate arrays Adders Microprocessors distributed processing Logic circuits Delay Testing Digital systems Design methodology Design optimization

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Feedback-Based Energy-aware Scheduling Algorithm for Hard Real-time Tasks

Feedback-Based Energy-aware Scheduling Algorithm for Hard Re...

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International Conference on Networking, Architecture, and Storage (NAS)

作者： Dong-song Zhang Shi-yao Jin Tong Wu Hua-wei Li National Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha China Zhenjiang Watercraft College Jiangsu China

In this paper, we propose a new algorithm for dynamic voltage scaling (DVS) based on feedback control mechanism. Besides handling a periodic tasks, our algorithm significantly reduces the energy consumption of periodic tasks and consequently the energy consumption of the whole task set. The results show that, comparing to on-line dynamic voltage scaling (the best algorithm to our knowledge), our approach improves the energy savings by 10% on most task sets tested and by 5% on average.

关键词： Scheduling algorithm Dynamic voltage scaling Feedback control Processor scheduling Real time systems Energy consumption Voltage control Switches Heuristic algorithms Dynamic scheduling

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Model-Directed Multi-Level parallelization for Multi-Task Programs on the Cell BE

Model-Directed Multi-Level Parallelization for Multi-Task Pr...

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International Symposium on Computer Science and its Applications, CSA

作者： Miao Wang Nicolas Benoit Francois Bodin National Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha China University of Rennes I Rennes France

ISBN: (纸本)9781424449453;9781424449460

Multi-core architectures can deliver high processing power if the multiple levels of parallelism they expose are exploited. However, it is non-trivial to orchestrate the computational and memory resources allocation. Furthermore, when dealing with distributed memory architectures, data distribution adds another level of complexity. This paper presents a model-driven technique for mapping multi-task parallel programs onto multi-core platforms. The resource allocation configurations are expressed within a three-dimensional optimization space which affects task-level and data-level parallelism, and communication. Then, the performance of any valid parallelization scheme is estimated statically, taking into account both computation and communication costs. We prototyped our approach on the Cell BE with an image processing application. Experiments show that our model can correctly predict the overall performance and highlight the most efficient parallelization schemes.

关键词： parallel processing Resource management Concurrent computing Multicore processing Image processing Predictive models Embedded computing Space exploration Laboratories distributed processing

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Numerical study of DIBL effect in Carbon Nanotube-FETs

Numerical study of DIBL effect in Carbon Nanotube-FETs

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IEEE Conference on Nanotechnology

作者： Hailiang Zhou Bingcai Sui Yaqing Chi Minxuan Zhang Yue Hao National laboratory of parallel and distributed processing National University of Defense Technology Changsha China Department of Microelectronics Xidian University Xi'an China

ISBN: (纸本)9781424448326

In CNFETs, the Drain Induced Barrier Lowing (DIBL) effect is still a primitive problem and open for further study. Based on a numerical model developed with the Non-Equilibrium Green's Function (NEGF) approach in real space, this paper studied the DIBL effect in Carbon Nanotube-FETs (CNFETs). Some interesting phenomena of the impact of DIBL on the energy band have been noticed. For example, the relationship between the degree of barrier lowing and the drain-source voltage is not linear but of a step-like quantization, and the energy band shape (gradient or aclinic) is closely related to Fermi-level. For the first time, a detailed explanation of the underlying physical mechanism of the observed DIBL effect is presented according to the electronic structure, the effective capacitance model and the quantum capacitance model of CNFETs. Then the correlation between DIBL effect and the insulator thickness, insulator dielectric constant, CNT diameter and channel length is studied. At the end, a conclusion is made by summarizing the differences between the DIBL effect in CNFETs and that in short channel MOSFETs, and several approaches is presented to reduce the leakage current resulting from the DIBL effect.

关键词： Carbon nanotubes Quantum capacitance Dielectrics and electrical insulation Numerical models Green's function methods Voltage Quantization Shape Dielectric constant MOSFETs

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A simple algorithm implementation for pattern-matching with bounded gaps in genomic and proteomic sequences, on the grid egee platform, using an intuitive user interface

A simple algorithm implementation for pattern-matching with ...

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5th IFIP Conference on Artificial Intelligence Applications and Innovations, AIAI 2009

作者： Vegoudakis, K.I. Margaritis, K.G. Maglaveras, N. Department of Applied Informatics Parallel and Distributed Processing Laboratory University of Macedonia 156 Egnatia str. P.O. Box 1591 54006 Thessaloniki Greece Lab of Medical Informatics Health Sciences Faculty Aristotle University AUTH PB 323 54124 Thessaloniki Greece

In the last decade an unprecedented development in bioinformatics has been observed. An extremely high number of organisms have been sequenced and included in genomic databases. The huge amount of data produced needs to be stored and processed for further analysis. Scientists, have researched algorithms for finding complicated patterns in DNA sequences, but there is a need for computational power and large storage systems, in order to implement specific algorithms in as many as possible DNA sequences stored in large Databases and save the results produced for future use. Recently, a number of pattern matching algorithms that allowing gaps have been introduced and Grid is an emerging technology that seems to be helpful in this kind of biomedical research. In this paper, we present our effort towards the construction of a user friendly Interface for accessing the Grid EGEE platform. The Interface is a specific one and was built to perform Pattern-Matching with Bounded Gaps in Genomic and Proteomic Sequences. The algorithm and the Interface is tested with small and large DNA and protein sequences as an input, downloaded from a gene and protein repository, NCBI (National Center for Biotechnology Information) and the gathered results produced are presented.

关键词： DNA sequences

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A Multi-agent Simulation of Escape Panic

A Multi-agent Simulation of Escape Panic

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International Joint Conference on Computational Sciences and Optimization, CSO

作者： Chuanjun Ren Chenghui Yang Shiyao Jin National Laboratory for Parallel & Distributed Processing College of Computer Science National University of Defense Technology Changsha China National Laboratory for Parallel & Distributed Processinz National University of Defense Technology Changsha China National University of Defense Technology Changsha Hunan CN

The modeling and simulation on evacuation has recently become a topic of great interest. We present an agent-based model to construct crowd evacuations for emergency response from an area under an explosion. Various types of agents are designed as well as the interactions of them are concerned in contrast to traditional models in which the total populations are considered to be consisted of identical individuals and the interactions between them are omitted. Different cases are taken into account to test the effect of our model by iterative simulations. At last, plenty simulation results suggest several effective ways to minimize the harmful consequences of such life-threaten events.

关键词： Explosions Computational modeling Computer simulation Testing Accidents Humans Analytical models Concurrent computing distributed computing distributed processing

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Laser-driven inertial ion focusing

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Physical Review E 2009年第1期79卷 015401(R)-015401(R)页

作者： H. B. Zhuo Wei Yu M. Y. Yu H. Xu X. Wang B. F. Shen Z. M. Sheng J. Zhang National Laboratory for Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha 410073 China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China Institute for Fusion Theory and Simulation Zhejiang University Hangzhou 310027 China Institute for Theoretical Physics I Ruhr University Bochum D-44780 Germany Department of Physics Jiaotong University Shanghai 200240 China

A Hohlraum-like configuration is proposed for realizing a simple compact source for neutrons. A laser pulse enters a tiny thin-shelled hollow-sphere target through a small opening and is self-consistently trapped in the cavity. The electrons in the inner shell-wall region are expelled by the light pressure. The resulting space-charge field compresses the local ions into a thin layer that becomes strongly heated. An inward expansion of ions into the shell cavity then occurs, resulting in the formation at the cavity center of a hot spot of ions at high density and temperature, similar to that in inertial electrostatic confinement.

关键词： laser fusion neutron sources particle beam focusing ELECTROSTATIC CONFINEMENT FUSION DEVICE

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Optimization techniques of on-chip memory system based on UltraSPARC architecture

Optimization techniques of on-chip memory system based on Ul...

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Asia Pacific Conference on Postgraduate Research in Microelectronics & Electronics (PrimeAsia)

作者： Anwen Huang Jun Gao Chaochao Feng Minxuan Zhang Key Laboratory of Science and Technology of National Defense of Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha China

It is of great significance to optimize the design of on-chip memory system for improving the performance of multi-core processor. This paper describes the organization of on-chip memory hierarchy in UltraSPARC T2, analyzes the procedure of dealing with the memory access request from multi-core processor in detail. To get the basic parameters of timing characteristic and area consumption, the primary element of on-chip memory system is simulated by ModelSim and synthesized by Synopsys Design Complier with 90 nm standard cell library. Aimed at the potential limiting factor of improving the performance of memory hierarchy, corresponding optimization techniques of critical elements in memory system are explored finally.

关键词： System-on-a-chip Elliptic curve cryptography Hardware Costs Algorithm design and analysis Random access memory Clocks Registers Elliptic curves Protection

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An Optimal Mapping Algorithm Based on Balanced Load Cutting for DVE Systems

An Optimal Mapping Algorithm Based on Balanced Load Cutting ...

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International Symposium on Intelligent Information Technology Application, IITA

作者： Wei Zhang Min Xi Hangjun Zhou Yuxing Peng Sikun Li National Laboratory for Parallel and Distributed Processing National University of Defense Technology ChangSha China Department of Computer Science Xi'an Jiaotong University Xi'an China

In distributed virtual environment (DVE) systems, a distributed server infrastructure is often used to reduce the latency between servers and clients. Under this infrastructure, mapping clients to proper servers is one of the key issues for improving the interactivity and overall performance. Most traditional methods of mapping the clients to servers only consider the load balancing problem. However, there are two other important aspects that should be involved: the physical world integrity and the virtual world integrity. In this work, we propose a novel mapping algorithm which takes care of all three aspects at the same time. The algorithm converts the mapping problem into cutting stage and matching stage to get optimal result with polynomial complexity. The experimental results show that our algorithm improves the overall performance of DVE systems significantly.

关键词： Delay Network servers Computer science Virtual environment Load management Polynomials Quality of service Information technology Application software distributed processing

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