检索结果-内蒙古大学图书馆

Canadian Conference on Electrical and computer engineering (CCECE)

作者： M.R. Hashemi L. Winger S. Panchanathan School of Information Technology and Engineering (SITE) University of Ottawa Ottawa ONT Canada Visual Computing and Communications Laboratory Department of Computer Science and Engineering Arizona State University USA

Digital video databases in compressed form are becoming widely available. In applications such as video browsing, and picture in picture, for a lower bitrate there is a need to down-sample the video before transmission. The conventional approach to downscale a compressed video sequence is to decompress it at the video server, perform the down-sampling in the pixel domain and recompress it again for efficient delivery. This process is computationally expensive due to the motion estimation process needed during the recompression phase. In the alternative compressed domain based approach the downscaled motion vectors are computed directly from the original ones. We propose a method to improve the process of downscaling in the compressed domain by better selecting the motion prediction type of P and B frame macroblocks. Simulations suggest that the proposed scheme improves the compressed domain down-sampling quality by up to 2.2 dB without any substantial increase in computation.

关键词： Transform coding Video compression Motion estimation Discrete cosine transforms Video sequences Image coding Visual databases Bit rate Image storage information technology

来源：评论

学校读者我要写书评

暂无评论

Structured spatial domain image and data comparison metrics 99

Structured spatial domain image and data comparison metrics

引用

Proceedings of the conference on Visualization '99: celebrating ten years

作者： Nivedita Sahasrabudhe John E. West Raghu Machiraju Mark Janus NSF Engineering Research Center Mississippi State University DoD High Performance Computing Center Information Technology Laboratory USAE Waterways Experiment Station and NSF Engineering Research Center Mississippi State University Department of Computer Science NSF Engineering Research Center Mississippi State University Department of Aerospace Engineering NSF Engineering Research Center Mississippi State University

ISBN: (纸本)9780780358973

Often, images or datasets have to be compared, to facilitate choices of visualization and simulation parameters respectively. Common comparison techniques include side-by-side viewing and juxtaposition, in order to facilitate visual verification of verisimilitude. In this paper, we propose quantitative techniques which accentuate differences in images and datasets. The comparison is enabled through a collection of partial metrics which, essentially, measure the lack of correlation between the datasets or images being compared. That is, they attempt to expose and measure the extent of the inherent structures in the difference between images or datasets. Besides yielding numerical attributes, the metrics also produce images, which can visually highlight differences. Our metrics are simple to compute and operate in the spatial domain. We demonstrate the effectiveness of our metrics through examples for comparing images and datasets.

关键词： correlation measure rendering metrics steering

来源：评论

学校读者我要写书评

暂无评论

Compressed domain motion vector resampling for downscaling of MPEG video

Compressed domain motion vector resampling for downscaling o...

引用

IEEE International Conference on Image Processing

作者： M.R. Hashemi L. Winger S. Panchanathan School of Information Technology and Engineering University of Ottawa Ottawa ONT Canada Visual Computing and Communications Laboratory Department of Computer Science and Engineering Arizona State University Saudi Arabia

Digital video databases in compressed form are becoming widely available. In applications such as video browsing, and picture in picture, for a lower bitrate, there is a need to down-sample the video before transmission. The conventional approach to downscale a compressed video sequence is to decompress it at the video server, perform the down-sampling in the pixel domain and then recompress it for efficient delivery. This process is computationally intensive due to the motion estimation process required during the recompression phase. In the alternative compressed domain approach, the motion vectors of the downscaled video sequence are computed directly from the motion vectors of the original full size stream. In this paper we propose a compressed domain technique that generates a better estimate for the downscaled motion vectors. Simulations suggest that the performance achieved with the proposed method is superior by up to 1 dB to the current compressed domain techniques.

关键词： Transform coding Video compression Video sequences Motion estimation Discrete cosine transforms Image coding Bit rate Image storage information technology Databases

来源：评论

学校读者我要写书评

暂无评论

Utilization of matrix structure to generate optimized code from MATLAB programs

引用

International Journal of Parallel Programming 1999年第2期27卷 73-96页

作者： Marsolf, Bret A. Gallivan, Kyle A. Wijshoff, Harry A. G. DEMACO Inc. Champaign IL United States Compl. Sci. and Engineering Program Florida State University Tallahassee FL United States High Performance Computing Division Department of Computer Science Leiden University Leiden Netherlands

The FALCON development environment was designed around three basic data representations: scalars, vectors, and dense matrices. Utilizing the FALCON interactive restructuring system, the environment has been enhanced to allow the identification of structures within sparse matrices, such as diagonal matrices or symmetric matrices, and the use of this information for improving performance of the generated code. In addition, the environment supports the modification of the representation of the data. Such modifications have been shown to provide significant performance improvements.

关键词： computer programming

来源：评论

学校读者我要写书评

暂无评论

Strategic directions in simulation research (panel) 99

Strategic directions in simulation research (panel)

引用

Proceedings of the 31st conference on Winter simulation: Simulation---a bridge to the future - Volume 2

作者： David M. Nicol Osman Balci Richard M. Fujimoto Paul A. Fishwick Pierre L'Ecuyer Roger Smith Ernest H. Page Department of Computer Science 6211 Sudikoff Laboratory Dartmouth College Hanover NH Department of Computer Science Virginia Polytechnical Institute & State University Blacksburg VA College of Computing Georgia Institute of Technology Atlanta GA Department of Computer & Information Science and Engineering University of Florida CSE 301 Gainesville FL Département d'Informatique et de Recherche Opérationelle Université de Montréal C.P. 6128 Succ. Centre-Ville Montréal Québec Canada H3C 3J7 BTG Inc. 3481 Woodley Park Place Oviedo FL The MITRE Corporation 1820 Dolley Madison Boulevard McLean VA

来源：评论

学校读者我要写书评

暂无评论

A study of code reuse and sharing characteristics of Java applications 1

A study of code reuse and sharing characteristics of Java ap...

引用

1st Workshop on Workload Characterization, WWC 1998

作者： Conte, M.T. Trick, A.R. Gyllenhaal, J.C. Hwu, W.W. Department of Electrical and Computer Engineering Coordinated Science Laboratory Center for Reliable and High-performance Computing University of Illinois at Urbana-Champaign United States

ISBN: (纸本)0769504507

Presents a detailed characterization of Java application and applet workloads in terms of reuse and sharing of Java code at the program, class and method level. In order to expose more sharing opportunities, techniques for detecting code equivalence even in the presence of minor code changes or constant pool index differences) are also proposed and examined. The analyzed application workload consists of the recently released SPECjvm98 benchmarks, and the applet workload is derived from three extensive searches of the Internet between May 1997 and May 1998 using an enhanced Web crawler. Analysis of these workloads reveals several new code sharing and optimization opportunities. © 1998 IEEE.

关键词： Java programming language

来源：评论

学校读者我要写书评

暂无评论

Efficient runtime thread management for the nano-threads programming model 12th

引用

10 Workshops held in conjunction with 12th International Parallel Symposium and 9th Symposium on Parallel and Distributed Processing, IPPS/SPDP 1998

作者： Nikolopoulos, Dimitrios S. Polychronopoulos, Eleftherios D. Papatheodorou, Theodore S. High Performance Computing Architectures Laboratory Department of Computer Engineering and Informatics University of Patras Rio Patras26500 Greece

ISBN: (纸本)3540643591

The nano-threads programming model was proposed to effectively integrate multiprogramming on shared-memory multiprocessors, with the exploitation of fine-grain parallelism from standard applications. A prerequisite for the applicability of the nano-threads programming model is the ability of the runtime environment to manage parallelism at any level of granularity with minimal overheads. In this paper, we introduce runtime techniques for efficient memory management and user-level scheduling in an experimental runtime system designed to support the nano-threads programming model. We evaluate the exploitation of processor affinity for the management of nano-thread contexts, and the use of hierarchical queues to implement user-level scheduling strategies for applications with inherent multilevel parallelism. The proposed mechanisms attempt to obtain maximum benefits from data locality on cache-coherent NUMA multip'rocessors. Through the use of synthetic benchmarks, we find that our mechanism for memory management in the runtime system reduces overheads by 52% on average, compared to other known mechanisms. The use of hierarchical queues gives significant performance improvements between 17% and 40%, compared to scheduling strategies that use local queues. © Springer-Verlag Berlin Heidelberg 1998.

关键词： Multiprogramming

来源：评论

学校读者我要写书评

暂无评论

Enhancing the performance of autoscheduling in Distributed Shared Memory multiprocessors

引用

4th International Conference on Parallel Processing, Euro-Par 1998

ISBN: (纸本)3540649522

Autoscheduling is a parallel program compilation and execution model that combines uniquely three features: Automatic extraction of loop and functional parallelism at any level of granularity, dynamic scheduling of parallel tasks, and dynamic program adaptability on multi-programmed shared memory multiprocessors. This paper presents a technique that enhances the performance of autoscheduling in Distributed Shared Memory (DSM) multiprocessors, targetting mainly at medium and large scale systems, where poor data locality and excessive communication impose performance bottlenecks. Our technique partitions the application Hierarchical Task Graph and maps the derived partitions to clusters of processors in the DSM architecture. Autoscheduling is then applied separately for each partition to enhance data locality and reduce communication costs. Our experimental results show that partitioning achieves remarkable performance improvements compared to a standard autoscheduling environment and a commercial parallelizing compiler.

关键词： Large scale systems

来源：评论

学校读者我要写书评

暂无评论

A grid-enabled MPI: Message passing in heterogeneous distributed computing systems

A grid-enabled MPI: Message passing in heterogeneous distrib...

引用

1998 ACM/IEEE Conference on Supercomputing, SC 1998

作者： Foster, Ian Karonis, Nicholas T. Mathematics and Computer Science Division Argonne National Laboratory ArgonneIL60439 United States High-Performance Computing Laboratory Department of Computer Science Northern Illinois University DeKalbIL60115 United States

ISBN: (纸本)081868707X

Application development for high-performance distributed computing systems, or computational grids as they are sometimes called, requires "grid-enabled" tools that hide mundane aspects of the heterogeneous grid environment without compromising performance. As part of an investigation of these issues, we have developed MPICH-G, a grid-enabled implementation of the Message Passing Interface (MPI) that allows a user to run MPI programs across multiple computers at different sites using the same commands that would be used on a parallel computer. This library extends the Argonne MPICH implementation of MPI to use services provided by the Globus grid toolkit. In this paper, we describe the MPICH-G implementation and present preliminary performance results. © 1998 IEEE.

关键词： Message passing

来源：评论

学校读者我要写书评

暂无评论

A multithreaded message-passing system for high performance distributed computing applications

A multithreaded message-passing system for high performance ...

引用

International Conference on Distributed computing Systems

作者： S.-Y. Park J. Lee S. Hariri High Performance Distributed Computing (HPDC) Laboratory Department of Electrical Engineering and Computer Science High Performance Distributed Computing HPDC Laboratory Syracuse University Syracuse NY USA

NYNET (ATM wide area network testbed in New York state) Communication System (NCS) is a multithreaded message passing system developed at Syracase University that provides high performance and flexible communication services over asynchronous transfer mode (ATM) based high performance distributed computing (HPDC) environments. NCS capitalizes on thread based programming model to overlap computations and communications, and develop a dynamic message passing environment with separate data and control paths. This leads to a flexible and adaptive message passing environment that can support multiple flow control, error control, and multicasting algorithms. We provide an overview of the NCS architecture and present how NCS point to point communication services are implemented. We also analyze the overhead incurred by using multithreading and compare the performance of NCS point to point communication primitives with those of other message passing systems such as p4, PVM, and MPI. Benchmarking results indicate that NCS shows comparable performance to other systems for small message sizes but outperforms other systems for large message sizes.

关键词： Message passing Asynchronous transfer mode Dynamic programming Communication system control Wide area networks System testing Distributed computing Yarn Computational modeling Programmable control

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：