Porting a high-order finite-element earthquake modeling application to NVIDIA graphics cards using CUDA

We port a high-order finite-element application that performs the numerical simulation of seismic wave propagation resulting from earthquakes in the Earth on NVIDIA GeForce 8800 GTX and GTX 280 graphics cards using CUDA. This application runs in single precision and is therefore a good candidate for implementation on current GPU hardware, which either does not support double precision or supports it but at the cost of reduced performance. We discuss and compare two implementations of the code: one that has maximum efficiency but is limited to the memory size of the card, and one that can handle larger problems but that is less efficient. We use a coloring scheme to handle efficiently summation operations over nodes on a topology with variable valence. We perform several numerical tests and performance measurements and show that in the best case we obtain a speedup of 25.     

正确认识计提固定资产折旧

当前，在企业计提固定资产折旧的实务操作中出现了许多违法违规行为，这不仅影响企业的经营决策。还造成企业自身的财务混乱，也给整个社会经济秩序带来不小的危害。本文就充分认识正确提折旧的必要性以及我国现行的计提折旧方法进行了剖析和论证。     

数据并行问题的性能分析及优化

针对并行处理的特点，主要提出了关于数据并行问题的优化理论和实现方法。     

PVM环境中提高并行计算效率的途径

本文通过对ＰＶＭ的分析与实际应用开发，分析了为提高基于工作站群机环境的并行计算效率应考虑的因素及应采取的一般措施。提出了在多网络构成的群机环境中采用按构成的网段分组实施动态负载平衡策略的方法以减少实施策略本身所带来的通信开销，这是通过减少节点间的负载平衡消息交互和任务迁移而达到的，模拟表明这是一种有效的策略。     

Parallel protein secondary structure prediction schemes using Pthread and OpenMP over hyper-threading technology

Protein secondary structure prediction has a fundamental influence on today’s bioinformatics research. In this work, tertiary classifiers for the protein secondary structure prediction are implemented on Denoeux Belief Neural Network (DBNN) architecture. Hydrophobicity matrix, orthogonal matrix, BLOSUM62 matrix and PSSM matrix are experimented separately as the encoding schemes for DBNN. Hydrophobicity matrix, BLOSUM62 matrix and PSSM matrix are applied to DBNN architecture for the first time. The experimental results contribute to the design of new encoding schemes. Our accuracy of the tertiary classifier with PSSM encoding scheme reaches 72.01%, which is almost 10% better than the previous results obtained in 2003. Due to the time consuming task of training the neural networks, Pthread and OpenMP are employed to parallelize DBNN in the Hyper-Threading enabled Intel architecture. Speedup for 16 Pthreads is 4.9 and speedup for 16 OpenMP threads is 4 in the 4 processors shared memory architecture. Both speedup performance of OpenMP and Pthread is superior to that of other research. With the new parallel training algorithm, thousands of amino acids can be processed in reasonable amount of time. Our research also shows that Hyper-Threading technology for Intel architecture is efficient for parallel biological algorithms.

PPS的集中和分布式并行分组交换算法分析

集中式并行分组交换算法（Centratized Parallel Packet Switch Algorithm,CPA)和分布式并行分组交换算法（Distribntd Parallel Packet Switch Algoritlun,DPA)是目前并分行分组交换（Parallel Packet Switch,PPS研究中的典型算法，该文对两种算法进行了描述及理论分析和性能比较，作出了两种算法的应用性分析，探讨了DPA算法实现需要继续研究和解决的几个关键问题。     

Speedup of color palette indexing in self-organization of Kohonen feature map

Based on the self-organization of Kohonen feature map (SOFM), recently, Pei et al. presented an efficient color palette indexing method to construct a color table for compression. Taking the palette indexing method as a representative, this paper presents two new strategies, the pruning-based search strategy and the lookup table (LUT)-based update strategy, to speed up the learning process in the SOFM. Based on four typical testing images, experimental results illustrate that our proposed two strategies have 35% execution-time improvement ratio in average. The practical improvement ratio is very close to that in the theoretical analysis.     

第Ⅱ类同型异构计算系统的新加速比模型

我们最近提出了同型异构计算系统ＨＣＳ－ＭＯＳＴ的概念,将它划分成三大类,并分别推导出它们的加速比模型。本文采用一种不同的应用任务模型来研究其中的第Ⅱ类ＨＣＳ〈０,ｍ＾＊,０〉系统,得到它的新加速比模型,并以ＨＣＳ〈０,１８＾＊,０〉系统粉列,对具有不同并行性分布的计算任务获得的计算结果进行分析讨论。     

Acceleration of CFD simulation of gas-solid flow by coupling macro-/meso-scale EMMS model

Gas-solid flow features significant dynamic multi-scale structure; multi-scale modeling is therefore in order. In this article, the macro-scale EMMS model was coupled with a two-fluid method (TFM) elaborated by the meso-scale EMMS model resolving sub-grid scale heterogeneity to simulate the hydrodynamics of circulating fluidized bed (CFB) risers. The overall flow distribution under the steady state was approximately predicted by the macro-scale EMMS model, which serves as the initial condition for meso-scale TFM simulations reproducing the dynamic behavior of heterogeneous gas-solid flows. Using the solid circulation flux as criterion, it was shown that this coupling approach can significantly reduce the time required to reach the statistically steady state, as compared to the packed bed or homogeneously dispersed initial condition. It also suggests a general approach to speedup dynamic simulation in the multi-scale paradigm of computation.     

Faster and more robust point symmetry-based K-means algorithm

Based on the recently published point symmetry distance (PSD) measure, this paper presents a novel PSD measure, namely symmetry similarity level (SSL) operator for K-means algorithm. Our proposed modified point symmetry-based K-means (MPSK) algorithm is more robust than the previous PSK algorithm by Su and Chou. Not only the proposed MPSK algorithm is suitable for the symmetrical intra-clusters as the PSK algorithm does, the proposed MPSK algorithm is also suitable for the symmetrical inter-clusters. In addition, two speedup strategies are presented to reduce the time required in the proposed MPSK algorithm. Experimental results demonstrate the significant execution-time improvement and the extension to the symmetrical inter-clusters of the proposed MPSK algorithm when compared to the previous PSK algorithm.