树型网格下独立任务的实用调度算法

讨论在节点计算能力和网络通信速度异构的树型网格下独立任务的调度问题。与最小化任务总执行时间不同（该问题被证明是NP难题[1]）,本文修正[2]中为树型网格平台任务调度问题建立的整数线性规划模型,针对多层树通过线性规划模型求解最优任务分配数的时间复杂性大（ ）的问题,引入推拉方法,将多层树线性规划求解归结为单层树求解,复杂性降低为 ,其中 ,m为树的层数, 为第j层中节点的数目最多的节点的子节点数。基于求出的近似最优任务分配数,提出一个静态分布式的启发式任务调度算法。分析和实验表明,在异构的树型网格下做大量的独立任务调度时,算法性能优于同类算法。 关键词: 任务调度; 网格计算; 线性规划; 最优任务分配; 分布式任务调度算法;     

经济网格中基于剪枝策略的时间-费用优化任务调度

由于在经济网格环境下,存在着资源异构和分布的特征,网格任务调度变成了一个复杂的问题.为此,针对独立任务,在考虑用户的服务质量经济需求偏好的基础上,提出了一个优化用户时间和费用的任务调度方案选择算法.该算法首先将网格中兼顾时间和费用的任务调度方案形式化为一个n层m叉树,然后将调度方案的选择问题转化为树的遍历问题,最后利用剪枝方法避免无效路径的搜索,降低了时间复杂度,实现了任务的优化调度.结果表明该算法能按照用户的时限和费用需求偏好选择优化的调度方案,且在性能上优于传统的未剪枝算法.所以该算法是一种可行的任务调度算法.     

一种基于任务竞争力的工作流调度算法

网格计算聚集了大量的异构分布式的计算或存储资源,为科学研究提供了一个高性能环境.然而,网格资源的异构性和自治性特征使得任务调度变得极其复杂.针对DAG表示的科学工作流调度问题,根据任务可用资源率确定任务调度的优先级,以任务竞争力刻画任务对资源的最佳匹配度,基于分层调度策略提出了一种基于任务竞争力的工作流调度算法.采用GridSim模拟实验表明该算法相对于其他两个算法,具有更小的执行时间.     

基于量子和克隆策略的负载均衡算法

针对网格计算中多个独立任务在多个异构的资源上处理时,资源的负载均衡为最小非抢先调度的问题,建立了一类资源负载均衡问题的优化调度模型.该模型将量子算法、克隆算法和遗传算法结合起来,提出一种新的混合量子克隆遗传调度算法.仿真实验表明在网格环境下,该算法全局寻优能力强,能有效地实现资源的负载均衡,并具有合理性和高效性.     

网格任务调度问题求解的萤火虫算法

为了获得更优的网格任务调度方案,针对网格环境特点以及标准萤火虫算法存在的不足,提出了一种基于改进萤火虫算法的网格任务调度优化模型.对网格任务调度优化问题进行了分析,建立了网格任务调度的数学模型,引入非均匀变异算子和自适应步长的搜索策略,加快算法的求解速度和精度,并将改进萤火虫算法用于网格任务调度问题求解,通过萤火虫之间的信息共享和交流找到网格任务调度最优方案,采用仿真对比实验对其有效性和优越性进行测试.结果表明,相对于其他网格任务调度优化算法,改进萤火虫算法可以快速、准确地找到网格任务的最优调度方案,提高了计算资源的利用率,保证了网格系统负载均衡,尤其对于大规模网格任务调度问题,具有更加明显的优势.     

网格环境下的高效动态任务调度算法

网格系统具有异构性、动态性和分布性，这使得网格中的任务调度变得十分复杂，要求调度算法具有动态性和自适应性．文中将群体智能技术引入网格的任务调度中，针对一组相互独立的任务调度问题，提出了一种新的动态任务调度算法．该算法利用蜂群与环境的交互模型来实现网格中动态的任务分配；同时根据蜂群的自组织社会层次的概念，解决了算法中出现的竞争问题．实验结果表明，相比于现有的方法，该算法对于网格中的动态环境具有更好的适应性，且调度性能更优．     

一种基于有向无环图的相依性网格任务调度算法

网格任务调度算法是影响网格成功与否的关键技术之一.本文首先描述了网格计算环境中的DAG任务调度模型.然后,结合网格计算环境的特点, 讨论了多个相依性任务组成的应用任务调度问题,并对GS和CIGS算法进行了全面而深入的研究,并在此基础上提出了一个CIGS算法的改进算法.     

异构任务图在网格环境中的调度实现

并行分布计算环境的任务调度一直是并行计算研究的热点问题，网格技术的发展则对任务调度提出了新的要求。本文采用带参数的有向超图表达异构任务图，为具有一般性、异构性、分布性、动态性等特点的任务请求提供了通用描述方法。通过设计网格异构任务图描述语言GHDL，实现了网格任务请求的统一封装以及任务请求在异构环境下的计算机理解和识别。通过设计自适应调度策略库，为分布异构动态网格环境下的任务调度提供有效解决方案，实现了在考虑网格任务间优先约束与数据关联的同时，采取异构宿主机识别、异构客户端自动创建等方式开发利用环境异构性与任务异构性，采取实时网格状态信息采集与任务迁移屏蔽了资源动态性。异构任务图在网格环境中的调度效果由树生长的仿真实验进行了展示。     

用于施工进度优化的VNS-CRO混合算法

针对现有研究中忽略施工任务分包资源系统异构的问题,结合建筑信息模型技术与异构环境下任务调度理论,提出变邻域搜索-化学反应混合优化算法,实现了对异构资源环境下道路施工进度计划任务调度与分包的优化.该算法在有向无环图模型与异构资源系统模型的基础上,融合了约束关键路径重排序策略,并在初始化与优化构造超级分子阶段,设计应用了一种平衡邻域结构的变邻域搜索方法,强化了算法的整体优化能力.模拟试验使用上海市陈翔路工程的实际工程数据,试验结果验证了所提出算法优化的有效性与鲁棒性及其相对其他算法的优势.     

网格资源管理系统中的任务调度策略研究

网格计算是继Internet和Web技术之后，又一次信息技术浪潮。由于资源具有广域分布、异构、动态等特性，网格环境下的资源管理和调度是一个非常复杂且具有挑战性的问题。通过分析比较当前多种环境下任务调度策略的基础之上，提出了一种适用于网格资源管理系统的多次映射任务调度策略。该策略在追求最短任务完成时间的同时，兼顾到了不同用户的需求，从而更好的适应了网格资源动态变化的特性。     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with