A framework for automating the configuration of OpenCL

Environmental research and scientific simulations use information acquired by sensors to validate the modeling and representation of environmental behaviors. The computational processing cost of this context tends to be extremely high due to the amount of information and the model's calculation complexities which demand the use of computational parallel solutions. This paper presents JSeriesCL, a framework for parallel processing of spatiotemporal series using graphics processors (GPGPU), more specifically OpenCL. GPU is cheaper than other solutions for parallel processing, such as clusters or grid, and JSeriesCL changes the way that GPU are used because it automates the configuration and management aspects of such devices. Fractal dimension and SEBS were used to validate the application of JSeriesCL over environmental data.     

An investigation of the performance portability of OpenCL

This paper reports on the development of an MPI/OpenCL implementation of LU, an application-level benchmark from the NAS Parallel Benchmark Suite. An account of the design decisions addressed during the development of this code is presented, demonstrating the importance of memory arrangement and work-item/work-group distribution strategies when applications are deployed on different device types. The resulting platform-agnostic, single source application is benchmarked on a number of different architectures, and is shown to be 1.3–1.5× slower than native FORTRAN 77 or CUDA implementations on a single node and 1.3–3.1× slower on multiple nodes. We also explore the potential performance gains of OpenCL’s device fissioning capability, demonstrating up to a 3× speed-up over our original OpenCL implementation.     

基于OpenCL的尺度不变特征变换算法的并行设计与实现

针对尺度不变特征变换（SIFT）算法实时性差的问题,提出了利用开放式计算语言（OpenCL）并行优化的SIFT算法。首先,通过对原算法各步骤进行组合拆分、重构特征点在内存中的数据索引等方式对原算法进行并行化重构,使得算法的中间计算结果能够完全在显存中完成交互;然后,采用复用全局内存对象、共享局部内存、优化内存读取等策略对原算法各步骤进行并行设计,提高数据读取效率,降低传输延时;最后,利用OpenCL语言在图形处理单元（GPU）上实现了SIFT算法的细粒度并行加速,并在中央处理器（CPU）上完成了移植。与原SIFT算法配准效果相近时,并行化的算法在GPU和CPU平台上特征提取速度分别提升了10.51～19.33和2.34～4.74倍。实验结果表明,利用OpenCL并行加速的SIFT算法能够有效提高图像配准的实时性,并能克服统一计算设备架构（CUDA）因移植困难而不能充分利用异构系统中多种计算核心的缺点。     

Dynamic analysis of eccentrically prestressed viscoelastic Timoshenko beams under a moving harmonic load

The dynamic response of eccentrically prestressed viscoelastic Timoshenko beams under a moving harmonic load is studied by using Lagrange equations. In the study, for using the Lagrange equations, trial functions denoting the deflection of the beam and the rotation of the cross-sections are expressed in polynomial forms. The constraint conditions of supports are taken into account by using Lagrange multipliers. The effects of the value of the eccentricity of the compressive load, the excitation frequency, the constant velocity of the transverse moving harmonic load and viscous damping of the material of beams are studied in detail. Convergence studies are made. The validity of the obtained results is demonstrated by comparing them with exact solutions based on the Euler–Bernoulli beam theory obtained for the special cases of the investigated problem.     

基于CPU与GPU协作的马尔可夫聚类的并行优化实现

马尔可夫聚类算法(MCL)为网络聚类问题提供了一个有效的方法,尤其是在社区问题和生物信息学方面。然而,矩阵的Expansion是最耗时的操作,因为两个大规模矩阵相乘的时间复杂度是n₃。由于每个元素值的计算是独立的,因此Expansion和Inflation可以并行执行于多核GPU上。一个基本的马尔可夫聚类的并行实现需要使用全邻接矩阵来提高性能,该邻接矩阵通常是稀疏的,有时甚至是极大稀疏的。因此,本文的马尔可夫聚类的并行优化实现采用CSR * CSC格式去存储矩阵,大大减少了空间的浪费,并在一定程度上提升了Expansion的性能。实验结果表明,在处理大规模网络问题上,Sparse-MCL比CPU-MCL和P-MCL更有效。     

低功耗AVR微处理器上Quark哈希算法优化实现

哈希算法被广泛用于数据完整性检测。在物联网数据完整性检测中,现有标准哈希算法的软硬件开销仍需进一步降低。从低功耗AVR微处理器的特点出发,通过基于字节的压缩函数变换操作和基于布尔运算特点的函数优化,以AVR ASM为开发语言环境给出了Quark哈希算法的优化实现,在算法实现的处理速度和存储开销上取得较好的平衡。     

Microfluidic systems for the analysis of viscoelastic fluid flow phenomena in porous media

In this study, two microfluidic devices are proposed as simplified 1-D microfluidic analogues of a porous medium. The objectives are twofold: firstly to assess the usefulness of the microchannels to mimic the porous medium in a controlled and simplified manner, and secondly to obtain a better insight about the flow characteristics of viscoelastic fluids flowing through a packed bed. For these purposes, flow visualizations and pressure drop measurements are conducted with Newtonian and viscoelastic fluids. The 1-D microfluidic analogues of porous medium consisted of microchannels with a sequence of contractions/expansions disposed in symmetric and asymmetric arrangements. The real porous medium is in reality, a complex combination of the two arrangements of particles simulated with the microchannels, which can be considered as limiting ideal configurations. The results show that both configurations are able to mimic well the pressure drop variation with flow rate for Newtonian fluids. However, due to the intrinsic differences in the deformation rate profiles associated with each microgeometry, the symmetric configuration is more suitable for studying the flow of viscoelastic fluids at low De values, while the asymmetric configuration provides better results at high De values. In this way, both microgeometries seem to be complementary and could be interesting tools to obtain a better insight about the flow of viscoelastic fluids through a porous medium. Such model systems could be very interesting to use in polymer-flood processes for enhanced oil recovery, for instance, as a tool for selecting the most suitable viscoelastic fluid to be used in a specific formation. The selection of the fluid properties of a detergent for cleaning oil contaminated soil, sand, and in general, any porous material, is another possible application.     

Identifying organizational requirements for the implementation of Advanced Manufacturing Technologies (AMT)

AMT selection and adoption processes have been extensively studied. Topics that include financial and human factors, productivity, and coordination of the AMT implementation establish a substantial content of the present research agenda. The purpose of this paper is to study the organizational factors that influence the AMT implementation, considering a manufacturing strategy context and an analysis based on an organizational design framework. The research strategy is based on ‘empirical iterations’ using survey secondary data, experts’ interviews information and multiple case studies. The results show that there is a set of recommendations, which strongly influence the AMT implementation. Companies require a structured and integrative approach for the AMT implementation in order to take advantage of all their individual and systemic benefits. The set of proposed AMT recommendations for integrating these technologies to the organizational design are framed by structural, process and contextual aspects.     

Exploiting the capabilities of modern GPUs for dense matrix computations

We present several algorithms to compute the solution of a linear system of equations on a graphics processor (GPU), as well as general techniques to improve their performance, such as padding and hybrid GPU‐CPU computation. We compare single and double precision performance of a modern GPU with unified architecture, and show how iterative refinement with mixed precision can be used to regain full accuracy in the solution of linear systems, exploiting the potential of the processor for single precision arithmetic. Experimental results on a GTX280 using CUBLAS 2.0, the implementation of BLAS for NVIDIA^® GPUs with unified architecture, illustrate the performance of the different algorithms and techniques proposed. Copyright © 2009 John Wiley & Sons, Ltd.     

SMIL及其流媒体集成的关键技术

本文介绍了同步集成多媒体语言SMIL的基本概念及其在流媒体集成时实现媒体组合、规划时间线和设置播放布局等几个关键技术,指出了实现这些技术的有关问题和策略,并给出了有关实例,实现了媒体播放的连续平滑和良好的视觉效果.     

关于同步部分规约的有限自动机的优化问题的近似难度

自动机是可同步的是指它具有满足以下性质的同步字:不论自动机当前所处的状态,以同步字为输入执行后它一定会到达某个特定状态。同步自动机问题的核心是计算最短同步字。聚焦于这一核心问题,文中就一类称为部分规约的确定的有限自动机的最短同步字问题,研究了近似计算这类自动机的最短同步字的复杂性,即近似计算它的难度,该工作有助于其近似算法的分析与设计。通过建立由两个优化问题(MAX SAT问题以及MAX FA-INT问题)到最短同步字长度计算这一问题(即Shortest-Syn)的归约,利用与概率可检验证明(Probabilistically Checkable Proofs,PCP)定理和概率可检验辩论(Probabilistically Checkable Debate,PCD)定理有关的若干结果证明了文中的主要结论:对于部分规约的确定的有限自动机,在某个近似因子内Shortest-Syn的近似难度是NP-难的和PSPACE-难的,除非NP和PSPACE分别坍塌到P。     

AVS反扫描、反量化和反变换模块的一种优化设计

根据AVS标准中的反扫描、反量化和反变换算法特点提出了一种用于AVS解码芯片中的反扫描、反量化和反变换硬件模块的设计方案,该设计以宏块为单位进行操作,便于集成到整个解码芯片的流水线中。同时,在宏块内实现了8×8子块的流水线操作并进行了优化,在反变换中用RAM代替寄存器堆进行转置操作。综合结果表明,该设计在获得了较高处理速度的同时节省了大量的寄存器和选择器资源。     

Finite element methods for the simulation of wave propagation in two-dimensional inhomogeneous elastic media

Several Galerkin procedures for obtaining approximate solutions for the wave equation in two-dimensional, inhomogeneous elastic media are presented. The numerical model utilizes an absorbing boundary condition in order to minimize the energy reflected by the artificial boundaries. Under certain smoothness hypotheses for the solution of the differential problem, optimal order convergence estimates are obtained.     

流式媒体同步集成技术在远程教学信息系统中的应用

现代教育技术并不等于现代远程教育,在教学过程中使用了现代信息技术并不就是现代远程教育。如何将数字视频／音频信息融于Web授课课件,这是当前远程教学和教育技术领域的新课题,该文介绍远程教学信息系统建设过程中进行的探索和实践。     

An efficient VLSI architecture and FPGA implementation of the Finite Ridgelet Transform

In this paper, an efficient architecture for the Finite Ridgelet Transform (FRIT) suitable for VLSI implementation based on a parallel, systolic Finite Radon Transform (FRAT) and a Haar Discrete Wavelet Transform (DWT) sub-block, respectively is presented. The FRAT sub-block is a novel parametrisable, scalable and high performance core with a time complexity of O(p ²), where p is the block size. Field Programmable Gate Array (FPGA) and Application Specific Integrated Circuit (ASIC) implementations are carried out to analyse the performance of the FRIT core developed.

机电一体化技术在综合采煤设备中的应用与发展

介绍了机电一体化技术在国内外煤矿井下综采设备中的应用，并论述了机电一体化技术发展与相关技术的研究。     

Integration of control system design and implementation over the internet using the Jini technology

This paper describes an approach for the integration of control system software design, testing, and implementation over the Internet using the Java and Jini technologies. Process models and control systems are remotely designed and tested in a virtual laboratory (also called the virtual world), and then implemented in a physical plant (also called the real world) through an integrated environment. Although control system and process model designers and real‐site operators are geographically dispersed they work together as a team over the Internet to provide the maintenance support to all the authorized industrial processes. As a consequence, time and money can both be saved because there is no need for an expert of the control software supplier to travel to the site of the real plant and conduct on‐site implementation. A generic control system life cycle model is presented first in this paper. Then three enabling technologies including Java, Jini and WWW are briefly introduced. Taking advantage of the Java, Jini and WWW technologies, an Internet‐based general infrastructure is proposed to remotely facilitate process modelling, control system design, simulation, validation and on‐site implementation. An integrated environment is established to implement the infrastructure. A water tank with a liquid level control system is refereed as a case study to illustrate how the prototype of the integrated environment works over the Internet. Further work and the conclusions are given at the end. Copyright © 2003 John Wiley & Sons, Ltd.     

A Proof of the Consistency of the Finite Difference Technique on Sparse Grids

In this paper, we give a proof of the consistency of the finite difference technique on regular sparse grids [7, 18]. We introduce an extrapolation-type discretization of differential operators on sparse grids based on the idea of the combination technique and we show the consistency of this discretization. The equivalence of the new method with that of [7, 18] is established. Received February 8, 2000; revised June 8, 2000     

基于主动测试的流媒体业务性能测量工具设计与实现

流媒体业务是推动下一代互联网发展的主要动力之一,对其性能的测量极为重要。根据流媒体业务性能测量的要求,借鉴主动测试技术,从端用户角度提出了合理反映流媒体业务性能的指标,分析了精确测量性能指标的方法,从而设计并实现了基于主动测试的流媒体业务性能测量工具,并对设计的关键问题做了分析。测量实验表明测量工具运行健壮,测量数据精确,取得了理想的效果。