基于改进时间指针的相控阵雷达任务调度方法

针对相控阵雷达实时任务调度中时间资源利用不充分的问题,提出了一种基于改进时间指针的任务自适应调度方法.以时间指针为对象,从整个调度时间轴上所有满足时间指针处执行条件的任务请求中,选择一个优先级最高的任务作为当前时刻的执行任务,有效减少了空闲时间的浪费,使得相控阵雷达能够在有限时间资源内调度执行更多的任务.与基于传统时间指针的调度方法仿真对比,结果表明:方法提高了任务调度成功率和时间利用率,有效提升1了相控阵雷达的整体调度性能,具有一定的优越性.     

被动相控阵雷达自适应调度算法研究

研究被动相控阵资源优化调度.相控阵雷达实现目标跟踪,精度和实时性是主要的指标.针对现有的主动相控阵资源调度不能很好地解决被动环境下搜索截获概率低,跟踪精度差的问题,提出一种被动相控阵雷达自适应调度算法(以下简称为被动自适应调度算法).算法根据被动截获、跟踪的特点,设计被动自适应调度算法的实现框架,重点研究了被动自适应调度的任务参数自适应生成、任务优先级评估及调度自适应执行等算法过程,并给出了被动自适应调度算法性能评估指标.仿真结果表明,该算法能优化安排被动相控阵雷达时、空、频等资源,缩短目标发现时间,保证跟踪稳定性.     

一种孔径分割多功能雷达的改进任务调度方法

针对孔径分割多功能雷达的实时任务调度问题,提出了一种改进的任务自适应调度方法.该方法充分利用任务时间窗的作用,根据任务的期望执行时刻和时间窗,主动调整任务的实际执行时刻,实现任务间的紧密安排,减少空闲资源的浪费,使得孔径分割多功能雷达能够在有限的资源内调度执行更多的任务.最后将该方法与传统多任务并行(MTPEDF)调度方法进行对比仿真,仿真结果表明该方法提高了任务调度成功率和资源利用率,有效提升了孔径分割多功能雷达的整体调度性能,具有一定的优越性.     

增强现实游戏中的并发多任务模型与实时调度方法

增强现实游戏软件系统属于典型的多任务并发实时系统.针对传统的分时调度模型不能很好地应对其实时调度的问题,提出一种基于抢占式时间Petri网和粒子群算法的方法.首先建立基于抢占式时间Petri网的并发多任务模型,描述了各任务线程的资源占用、时间性能指标和优先级关系等;其次提出基于粒子群算法的任务优化序列搜索方法,并通过构建应用实例阐述了使用该方法进行系统调度优化的典型过程.与相关的任务调度算法进行对比分析的结果表明,该方法具有良好的实时性能特征.     

一种MapReduce实时调度算法设计及实现

MapReduce是云计算中重要的批数据处理框架,多任务共享MapReduce机群并满足任务实时性要求是调度算法急需解决的问题。提出两阶段实时调度算法,将调度划分为任务间调度和任务内调度。对于任务间调度,使用抽样法和经验值法确定子任务执行时间,利用该参数建立资源分配模型,动态确定任务优先级进行调度;对于子任务使用延迟调度策略进行调度,保证计算的本地性。实验结果显示,两阶段实时调度算法相比公平调度算法和FIFO算法,在保证吞吐量的同时能够满足任务实时性要求。     

一种成本和时间均衡的网格资源分类优化调度策略

针对时间和成本约束的网格资源调度问题,提出一种基于MinCTT算法的时间和成本均衡的网格资源分类优化调度算法.该算法综合考虑任务完成时间和执行成本两个QoS因素,由一个成本比值和时间比值的联合均衡值来综合衡量任务在资源上的完成时间和执行成本开销,根据任务估计平均价格,对资源进行分类调度.实验结果表明,该调度算法具有较好的调度性能,能有效的减少任务总的完成时间和执行成本,均衡因子的改变对该算法的调度性能影响较小,选择合适的均衡因子能实现优的调度.     

iVCE中基于可信评价的资源调度研究

随着网格计算、P2P、Web服务技术在电子商务、电子政务领域应用的不断扩展,基于Internet的资源共享的安全可信问题变得越来越重要.该文在基于Internet的虚拟计算环境(Interenet-Based Virtual Computing Environment,iVCE)的资源共享的用户与资源关于身份可信、能力可信、行为可信的信任模型的基础上,提出了一种可信优化的资源调度算法.算法基本思想在于根据用户对资源可信的需求,对虚拟计算环境中的自主元素可信度综合考察与评价,以用户可信满意度为优化调度目标调度资源,进而基于min-min算法优化任务执行时间,满足了资源调度的可信保障,同时具有较好的性能.仿真实验结果表明可信优化调度算法能够在iVCE的信任度效益,最早完工时间,失效服务请求数,资源利用率等性能参数方面明显优于min-min和max-min算法.     

基于模因优化和循环调度的多目标负载均衡技术

针对现有多目标调度方法所需时间较长以及处理突发情况时性能降低的问题,提出一种基于模因优化和循环调度的多目标负载均衡技术。使用突发检测器检测发送到云服务器的用户请求,确定负载状态。基于测器结果,应用不同的负载平衡算法来高效地调度用户任务。利用选定的负载平衡算法将用户请求任务调度到资源最佳的虚拟机上,保证在最低的时间消耗内达到负载均衡的状态。实验结果表明,与其他算法相比,该方法在多个性能指标上具有明显优势,可以提高调度效率的同时,最大限度地降低云中的能源使用。     

红外低轨星座多目标传感器调度研究

关于卫星多目标传感器调度问题,由于资源有限,实时调度很难解决.为解决上述问题,保证长时间目标接力跟踪和并行多任务处理,提高实时调度能力,通过详细定义和建立数学模型,提出了自适应多任务规划概率选择算法,用趋势捕捉、概率选择和克隆变异防止陷入局部最优.采用启发规则避免了进化算法的盲目性.进行仿真的结果表明,算法能更好地解决多个优化目标及多个任务条件下传感器实时调度问题.     

空间探测相控阵雷达系统的任务优化编排仿真

任务优化编排是空间探测相控阵雷达系统效能发挥的关键.传统的空间探测大多采用探测时段局部优化的思路,可能导致任务丢失,不利于对空间目标的编目维持.针对上述问题,设计了一种全局的任务优化编排方法,利用空间目标过境的可预测性和周期性,挖掘探测任务无丢失和资源利用均衡程度的内在关系,提出了表征资源使用均衡程度的物理量——资源熵.然后通过资源熵引导雷达为过境目标选择合适的探测时段编排任务,实现了资源不过载条件下的任务无丢失规划.仿真结果表明,提出的编排算法显著提高了雷达系统时间资源利用的合理性,而且更加符合对空间目标编目维持的需求.     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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