检索结果-内蒙古大学图书馆

ICETC 2010 - 2010 2nd International Conference on Education technology and computer 2010年 4卷 V495-V498页

作者： Zhou, Hangjun Zhang, Wei Peng, Yuxing Li, Sikun Key Laboratory of Science and Technology for National Defence of Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha Hunan 410073 China Department of Information Management Hunan College of Finance and Economics Changsha Hunan 410205 China

ISBN: (纸本)9781424463688

In large-scale asynchronous distributed virtual environments(DVEs), one of the difficult problems is to deliver the concurrent events in a consistent order at each node. Generally, the previous consistency control approaches can be classified into two categories: causal order and time stamped order. However, causal order approaches can merely preserve the cause-effect relation of events and time stamped order approaches seem intrinsically complex to be used in serverless large-scale asynchronous DVEs. In this paper, we proposed a novel distributed algorithm to identify the concurrent events and preserve the consistent order delivery of them at different nodes. Simulation studies are also carried out to compare the performance of this algorithm with that of the previous ones. The results show that the new algorithm can effectively deliver the concurrent events in consistent order at each node and is more efficient than the previous algorithms in large-scale asynchronous DVEs. © 2010 IEEE.

关键词： Virtual reality

来源：评论

学校读者我要写书评

暂无评论

Implementation of encrypted data for outsourced database

Implementation of encrypted data for outsourced database

引用

International Conference on Computational Intelligence and Natural Computing, CINC

作者： Zheng-Fei Wang Ai-Guo Tang National Key Laboratory of Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha China Department of Computer Hunan Business College Changsha China

ISBN: (纸本)9781424477050

Encryption technology has become an important mechanism of securing data stored in the outsourced database. However, it is a difficulty to query efficiently the encrypted data and many researchers take it into consideration. To solve the problem, an encrypted schema, based on the Postgresql DBMS, is proposed. Through the security dictionary and the extended SQL, the approach implements the encrypted storage and efficiently query over the encrypted data in the outsourced databases. Results of experiments validate the efficiency and feasibility of our approach.

关键词： Indexes Dictionaries Random access memory Catalogs Encryption

来源：评论

学校读者我要写书评

暂无评论

Blocking LU Decomposition for FPGAs

Blocking LU Decomposition for FPGAs

引用

Annual IEEE Symposium on Field-Programmable Custom Computing Machines (FCCM)

作者： Guiming Wu Yong Dou Gregory D. Peterson National Laboratory for Parallel & Distributed Processing National University of Defense Technology Changsha China Electrical Engineering and Computer Science University of Tennessee Knoxville TN USA

To efficiently perform large matrix LU decomposition on FPGAs with limited local memory, the original algorithm needs to be blocked. In this paper, we propose a block LU decomposition algorithm for FPGAs, which is applicable for matrices of arbitrary size. We introduce a high performance hardware design, which mainly consists of a linear array of processing elements (PEs), to implement our block LU decomposition algorithm. A total of 36 PEs can be integrated into a Xilinx Virtex-5 xc5vlx330 FPGA on our self-designed PCI-Express card, reaching a sustained performance of 8.50 GFLOPS at 133 MHz, which outperforms previous work.

关键词： Field programmable gate arrays Matrix decomposition Hardware Power engineering computing Algorithm design and analysis Linear algebra computer applications Concurrent computing distributed computing Laboratories

来源：评论

学校读者我要写书评

暂无评论

Routing with uncertainty in wireless mesh networks

Routing with uncertainty in wireless mesh networks

引用

International Workshop on Quality of Service

作者： Fajun Chen Jiangchuan Liu Zongpeng Li Yijie Wang Key Laboratory of Science and Technology for National Defence of Parallel and Distributed Processing National University of Defense Technology China School of Computing Science Simon Fraser University Department of Computer Science University of Caglary

Existing routing protocols for Wireless Mesh Networks (WMNs) are generally optimized with statistical link measures, while not addressing on the intrinsic uncertainty of wireless links. We show evidence that, with the transient link uncertainties at PHY and MAC layers, a pseudo-deterministic routing protocol that relies on average or historic statistics can hardly explore the full potentials of a multi-hop wireless mesh. We study optimal WMN routing using probing-based online anypath forwarding, with explicit consideration of transient link uncertainties. We show the underlying connection between WMN routing and the classic Canadian Traveller Problem (CTP). Inspired by a stochastic recoverable version of CTP (SRCTP), we develop a practical SRCTP-based online routing algorithm under link uncertainties. We study how dynamic next hop selection can be done with low cost, and derive a systematic selection order for minimizing transmission delay. We conduct simulation studies to verify the effectiveness of the SRCTP algorithms under diverse network configurations. In particular, compared to deterministic routing, reduction of end-to-end delay (51.15~73.02%) and improvement on packet delivery ratio (99.76%) are observed.

关键词： Uncertainty Wireless mesh networks Delay Routing protocols Physical layer Statistics Stochastic processes Relays computer networks Concurrent computing

来源：评论

学校读者我要写书评

暂无评论

A consistency algorithm for causal and totally ordered event delivery in DVE

A consistency algorithm for causal and totally ordered event...

引用

International Conference on computer science and Information technology (CSIT)

作者： Hangjun Zhou Wei Zhang Yuxing Peng Sikun Li Department of Information Management Hunan College of Finance and Economics Changsha Hunan China Key Laboratory of Science and Technology for National Defence of Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha Hunan China

How to preserve causal and totally ordered event delivery is an important issue in real-time serverless DVE(distributed Virtual Environment). However, most of the related works are designed to maintain causal order merely or time stamped order with intensive computation and bandwidth overhead. In this paper, we proposed a novel distributed algorithm to maintain the before-and-after relationship between events, both causal and concurrent, of DVE at each individual node. Several simulation experiments are carried out to evaluate the performance of our algorithm and the results demonstrate that the algorithm is effective in preserving causal and totally ordered event delivery and more efficient than the previous algorithms.

关键词： Artificial neural networks Silicon Educational institutions

来源：评论

学校读者我要写书评

暂无评论

Reuse-aware modulo scheduling for stream processors 10

Reuse-aware modulo scheduling for stream processors

引用

Design, Automation and Test in Europe Conference and Exhibition

作者： Li Wang Jingling Xue Xuejun Yang National Laboratory of Parallel and Distributed Processing School of Computer National University of Defense Technology China Programing Languages & Compilers Group School of Computer Science and Engineering University of New South Wales Australia

ISBN: (纸本)9783981080162

This paper presents reuse-aware modulo scheduling to maximizing stream reuse and improving concurrency for stream-level loops running on stream processors. The novelty lies in the development of a new representation for an unrolled and software-pipelined stream-level loop using a set of reuse equations, resulting in simultaneous optimization of two performance objectives for the loop, reuse and concurrency, in a unified framework. We have implemented this work in the compiler developed for our 64-bit FT64 stream processor. Our experimental results obtained on FT64 and by simulation using nine representative stream applications demonstrate the effectiveness of the proposed approach.

关键词： Processor scheduling Concurrent computing Streaming media Kernel Delay Equations Pipeline processing Laboratories Program processors distributed processing

来源：评论

学校读者我要写书评

暂无评论

Using Redundant Threads for Fault Tolerance of OpenMP Programs

Using Redundant Threads for Fault Tolerance of OpenMP Progra...

引用

International Conference on Information science and Applications (ICISA)

作者： Hongyi Fu Yan Ding Key Laboratory of Science and Technology for National Defence of Parallel and Distributed Processing National University of Defense Technology Changsha Hunan China Section #620 School of Computer National University of Defense Technology Changsha Hunan China

ISBN: (纸本)9781424459421

As the wide application of multi-core processor architecture in the domain of high performance computing, fault tolerance for shared memory parallel programs becomes a hot spot of research. For years, checkpointing has been the dominant fault tolerance technology in this field, and recently, many research works have been engaged with it. However, to those programs which deal with large amount of data, checkpointing may induce massive I/O transfer, which will adversely affect scalability. To deal with such a problem, this paper proposes a fault tolerance approach, making use of redundancy, for shared memory parallel programs. Our scheme avoids saving and restoring computational state during the program's execution, hence does not involve I/O operations, so presents explicit advantage over checkpointing in scalability. In this paper, we introduce our approach and the related compiler tool in detail, and give the experimental evaluation result.

关键词： Fault tolerance Checkpointing Scalability Hardware Application software Multicore processing High performance computing Laboratories distributed processing

来源：评论

学校读者我要写书评

暂无评论

Personalized Reputation Model in Cooperative distributed Systems

Personalized Reputation Model in Cooperative Distributed Sys...

引用

International Conference on parallel and distributed Systems (ICPADS)

作者： Wei Liu Yang-Bin Tang Huai-Min Wang School of Computer National University of Defense Technology Changsha Hunan China National Laboratory for Parallel and Distributed Processing Changsha Hunan China Institute of Science National University of Defense Technology Changsha Hunan China

Reputation systems provide a promising way to build trust relationships between users in distributed cooperation systems, such as file sharing, streaming, distributed computing and social network, through which a user can distinguish good services or users from malicious ones and cooperate with them. However, most reputation models mainly focus on evaluating the qualities of different services in one dimension, but care less about the preferences of different users. This paper proposes a personalized reputation model which provides each user a personalized trust view on others according to his preference. In our approach, we aggregate the users' preferences with collaborative filtering method and qualify it with user similarity which is integrated into the computing of reputation values. The experimental results suggest that our model can resist possible kinds of malicious behaviors efficiently.

关键词： Computational modeling Measurement Indexes Aggregates Resists Peer to peer computing Electronic mail

来源：评论

学校读者我要写书评

暂无评论

An irregular cutting based distributed mapping algorithm for DVE systems

An irregular cutting based distributed mapping algorithm for...

引用

2009 2nd Asia-Pacific Conference on Computational Intelligence and Industrial Applications, PACIIA 2009

作者： Zhang, Wei Zhou, Hangjun Peng, Yuxing Li, Sikun Xi, Min National Laboratory for Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha 410073 China Department of Computer Science Xi'an Jiaotong University Xi'an 710049 China

ISBN: (纸本)9781424446070

distributed Virtual Environment (DVE) systems have become more and more important both in academic communities and the industries. To guarantee the load constrain, the physical world integrity and the virtual world integrity, the virtual environment should be divided into several parts and mapped to multiple servers, which are located in geographically different places. Many centralized algorithms based on regular cutting method are proposed to solve this problem. However, the dynamic property of clients and distributed property of the system make the existing algorithms unable to undertake it. In this paper, we propose a metric to measure the cutting quality and design a distributed mapping algorithm based on an irregular cutting. Simulation results show that our algorithm greatly decreases the costs of DVE systems for migration of clients and effectively improves the satisfaction degree of users. ©2009 IEEE.

关键词： Virtual reality

来源：评论

学校读者我要写书评

暂无评论

Fast query over encrypted data based on B+ tree

Fast query over encrypted data based on B+ tree

引用

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

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：