实时协同标绘系统中的即时锁共享机制研究

针对协同GIS应用中的并发与协同,提出了一种即时锁共享机制.其基本思想是在一定的协同感知基础上,允许产生一定的冲突,然后加以解决.对于共享锁用户并发操作导致的冲突意愿保护,采用了有向二叉树结构存储的并发版本方法.冲突的解析则利用角色和投票相结合的方法.此机制已经在CoGIS中实现,结果证明它可以在保证数据一致性的基础上提高系统的整体性能.     

基于角色权限的OVE并发控制策略研究

在虚拟协同环境中,必然存在多个用户对共享对象进行并发访问,冲突不可避免.现有系统所采用的锁定机制,要求用户在对物体修改之前先进行锁定,造成多个用户始终处于等待状态而不能对共享对象施加有效操作,从而影响系统的执行效率.针对目前并发控制策略的这一缺陷,本文归纳了虚拟协同环境中并发控制策略的通用设计准则,引入了角色权限机制,在传统锁定机制基础上,提出了一种基于角色权限的虚拟协同环境并发控制策略.这个策略在一定程度上保证了虚拟协同环境的一致性,有效地改善和优化了系统性能.     

基于角色权限的CVE并发控制策略研究

在虚拟协同环境中,必然存在多个用户对共享对象进行并发访问,冲突不可避免。现有系统所采用的锁定机制,要求用户在对物体修改之前先进行锁定,造成多个用户始终处于等待状态而不能对共享对象施加有效操作,从而影响系统的执行效率。针对目前并发控制策略的这一缺陷,本文归纳了虚拟协同环境中并发控制策略的通用设计准则,引入了角色权限机制,在传统锁定机制基础上,提出了一种基于角色权限的虚拟协同环境并发控制策略。这个策略在一定程度上保证了虚拟协同环境的一致性,有效地改善和优化了系统性能。     

网络化制造集成平台智能登录系统研究

为了解决面向服务的网络化制造平台集成体系中登录问题,提出了一种网络化制造集成平台智能登录系统.该系统采用智能登录服务器,既能实现集中式身份认证管理和分布式访问控制,又能保持集成平台中异构应用系统原有用户管理模块的独立性.详细介绍了其基本原理及实现机制,并给出了网络化制造集成平台智能登录系统的应用实例.     

基于MAS的分布式协同设计任务冲突处理研究

任务分解与冲突控制是网络分布式环境下进行产品并行设计的关键．通过收集产品各领域的指标约束与关系约束来构建基于约束网络的产品参数协调模型，采用区间描述设计变量的不确定性信息，并将区间算法与基因算法相结合实现了一致性模型求解框架，使用该方法能够检测潜在冲突，得到与给定产品指标相对应的设计变量可靠解空间，进而辅助设计人员决策。同时采用Agent技术对协同设计中多群体多层次的设计任务和设计进程进行管理和控制，建立了以项目和任务为中心的协同设计Agent模型，研究了模型共享、协同设计agent、并发控制机制等关键技术，构建了一个基于多Agent的分布式实时协同设计原型系统应用实例说明了其有效性。     

基于轨迹灵敏度的协同分布式模型预测电压控制

为克服集中式模型预测电压稳定控制的局限性,基于系统分区和预测电压控制模型分解提出了一种适于大型电力系统的协同分布式模型预测电压控制方法.该方法以所有子区域目标函数的凸组合来构建全局目标代价函数,利用轨迹灵敏度技术预测节点电压变化轨迹,将目标代价函数转化成与所有子区域控制变量有关的二次函数,从而避免了各子区域之间目标优化可能存在的冲突.在两个试验系统上的仿真结果表明,文中方法能获得与集中式模型预测电压控制相近的效果,且计算效率显著提高.     

支持异地协同设计的异构CAD虚拟装配系统

针对跨区域企业协同设计需求和现有基于CAD系统的虚拟装配只能单机操作的矛盾,基于虚拟现实建模语言(VRML)通用格式设计了支持异地协同设计的异构CAD模型虚拟装配系统。提出一种VRM L零件装配特征参数提取方法,在此基础上实现了零件装配约束;针对当前互联网环境低传输速率特点,使用基于参数-命令的操作命令传输机制,并运用操作令牌思想解决了协同过程中产生操作冲突的问题;在V-collide函数库的基础上实现了零件动态碰撞检测。通过与产品数据管理系统集成,应用到了产品设计、展示、售后维修整个生命周期过程,提高了设计沟通效率。     

解耦设计中分布式并行协同求解方法

随着并行工程、分布式人工智能学科的发展,从分布式协同求解角度进行解耦研究成为复杂机电系统的重要研究方向．作者介绍了基于分布式并行协同求解进行解耦设计的组织原则和策略,描述了协同求解智能主体的内部结构和功能模块,说明了每一智能主体的工作机理,并进而对协同求解过程中的通信机制作出初步设计．     

支持异地协同设计的异构CAD虚拟装配系统

针对跨区域企业协同设计需求和现有基于CAD系统的虚拟装配只能单机操作的矛盾,基于虚拟现实建模语言(VRML)通用格式设计了支持异地协同设计的异构CAD模型虚拟装配系统。提出一种VRML零件装配特征参数提取方法,在此基础上实现了零件装配约束;针对当前互联网环境低传输速率特点,使用基于参数-命令的操作命令传输机制,并运用操作令牌思想解决了协同过程中产生操作冲突的问题;在V-collide函数库的基础上实现了零件动态碰撞检测。通过与产品数据管理系统集成,应用到了产品设计、展示、售后维修整个生命周期过程,提高了设计沟通效率。     

智能光网络中基于冲突避免的通道恢复机制

为了避免资源冲突引起的恢复操作失败,提出一种适用于智能光网络中基于冲突避免算法的通道恢复机制。该机制采用染色算法将节点映射至不同波长区间,选择不同的起点进行波长搜索,使相邻节点对为共用同一条链路的业务尽可能选用不同的波长进行恢复。仿真结果表明:在双链路随机故障下,该算法能显著降低冲突概率,恢复成功率明显高于现有的基于首次命中和随机波长分配算法的分布式恢复机制。同时,该机制保持通道恢复的分布式特性,没有额外的信令开销,适合大规模网络应用。     

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-