多核构架下基于OpenMP 的Huffman压缩算法并行设计

本文是对多核程序设计的一种探索,在OpenMP模型下以赫夫曼算法为基础设计并行压缩程序.首先对传统的串行程序进行分析,使应用程序开发人员了解程序行为、发现性能瓶颈、明确优化方向.再用OpenMP的基本结构进行并行程序的设计之后,借助开发工具对并行程序进行优化和调试,得到改进方案.然后在双核处理器上分别运行并行程序与串行程序,将两者进行性能上的比较,实验结果证明性能得到很大程度地提高。     

基于占优关系的MPI并行程序死锁检测

随着高性能技术的发展,MPI并行程序得到了越来越广泛的应用,其可靠性也得到了软件工程界越来越多的关注.一个MPI并行程序有多个并行执行的进程,每个进程包含一系列串行执行语句.死锁是并行程序的一类典型错误,本文提出一种基于占优关系的死锁检测方法.首先,根据通信语句之间的占优关系,得到每个进程内,通信边之间的占优关系;然后,通过判定通信边占优关系是否相互违背,检测程序中的死锁.基于上述思想,开发了基于占优关系的死锁检测原型工具,用于检测多个典型的MPI并行程序.结果表明,本文方法能够检测出程序中的死锁缺陷.     

基于多核系统的隐马尔可夫模型并行算法研究

介绍了一种基于Open MP的多核并行程序设计方法,并使用此方法实现了对基于隐马尔可夫模型的Web文本挖掘程序的并行化改造.实验证明重新设计的多核并行程序相比于原有串行程序在多核微机系统上的运行时间大大减少、程序整体性能得到明显提升.     

一种面向并行程序的代码调试分析工具设计实现

并行程序的应用在提高程序运行效率的同时,也带来了不确定性的错误.这种错误往往难以复现,传统的调试工具越发难以满足并行程序的调试需求.据此提出了一种面向并行程序错误检测以及确定性回放的方法,针对并行程序中容易发生的数据竞争、死锁、原子性违反这几类错误进行检测判断;对并行程序的运行进行插桩以保证程序重复执行时的次序一致.在此理论基础上设计实现了Eclipse插件.通过试验,该工具可以对并行程序易发的错误进行有效的检测判断,较大程度地减少程序调试的工作量.     

Horde:面向多核集群的并行编程框架

并行程序可以充分发掘硬件计算能力并提高程序性能,但是在多核集群环境中编写并行程序十分复杂。该文提出了面向多核集群的并行编程框架,Horde。Horde提供了一组简单易用的消息传递接口和事件驱动(event-driven)编程模型,用以帮助程序员表达算法逻辑中潜在的并行性,将计算分解与底层硬件结构去耦合,从而简化编写并行程序的复杂度,灵活地在不同的底层结构的集群上进行映射并能保持良好的性能。此外,Horde也提供了有效的任务对象迁移机制,可以实现动态负载均衡与在线容错。在128核集群上的实验表明:Horde可以有效执行并行程序,并且可以实现高效的任务对象迁移。     

基于云平台的MapReduce性能优化策略

设计了基于云平台架构的M印Reduce性能优化策略,全面考虑MapReduce作业过程中的数据传输与数据处理流程,将虚拟网络拓扑结构的设计描述成一个优化问题,并构建模型实现了通信代理数量、通信代理的放置位置以及虚拟机与通信代理之间的映射关系,以解决目前大多数研究只单方面考虑平台的数据处理或数据传输性能的缺陷.实验结果表明,与随机匹配策略和贪心策略相比,本方案优化了云计算系统的虚拟网络拓扑结构,减少了数据传输与处理的时间总开销,显著地提高了大数据处理的整体性能.     

基于MMAS的NoC低功耗映射

随着芯片集成度的提高,网络通信流量与通信功耗也随之递增.片上网络在设计阶段就要考虑到通信功耗问题,因此提出一种可以降低通信功耗的映射方法,该方法是一种改进的最大最小蚁群算法,通过优化权重系数、状态转移规则以及信息素更新来提高算法的性能.实验表明,该方法能加速搜索进化过程,避免搜索的停滞,具有较好的收敛性,能有效的降低系统的映射功耗.     

Warshall算法在MPI中的实现及优化

Message Passing Interface并行编程方法是目前编程人员广泛使用的方法之一，但此方法将并行性开发的任务完全交给编程人员，程序的质量与效率往往因编程人员水平及风格不同而各异，在Message Passing Interface环境下把传统串行程序转变为并行程序从而提高其性能．此外通过MPI所提供的函数来进一步优化并行程序以便提高其性能，     

ARM11 MPCore性能分析与优化研究

ARM11 MPCore是最新的嵌入式多核处理器,传统的嵌入式软件在该平台上不能发挥该处理器的所有性能.针对这个问题,对ARM11 MPCore的基本运算能力与ARM9处理器进行了对比分析,提出了使用硬件向量浮点单元及并行计算的软件优化方法,实验结果表明优化后的MPCore浮点处理能力是ARM9系列处理器的浮点处理能力的10倍左右.对于多核架构,可以采用并行计算模型对软件进行优化,试验结果表明,对整数运算采用OpenMP并行计算模型优化后,实验程序的效率提高3.8倍左右.对于嵌入式多媒体处理,提出了使用硬件向量浮点单元对DCT运算进行优化,对视频解码、音频解码以及音视频同步显示采用并行处理的方法进行优化.实验结果表明,这两种优化方法能提高软件在ARM11 MPCore平台上的运行效率,提高了系统的整体性能.     

基于时延Petri网的并行程序的分析

在分析并行程序时,很多问题需要考虑,如通信、同步、数据划分和分配、负载平衡、容错、异构、死锁及竞争等问题,采用一般方法是很困难的.时延Petri网能够很好地描述这些问题,使并行程序的分析变得简单,且有利于并行程序的分割.给出了并行程序的时延Petri网建模方法,并对一个实例进行了分析,得出了并行程序的Petri网模型,对并行程序的分析及验证打下了基础.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-