一种扩展的虚拟树型网格可靠性评估模型

在已有虚拟树型网格可靠性评估模型的基础上引入了"截止时间违约失效",提出一种扩展的网格可靠性评估模型,用于支持实时网格任务的可靠性评估.该扩展模型采用队列系统来建立网格资源的负载模型,解决了原模型中不支持并行资源和无法感知动态负载的缺陷.理论分析给出了模型的有效性证明和实时性任务的可靠性计算方法.实验结果显示,在饱和负载状态下,该扩展模型能显著提高可靠性评估的准确性,其动态负载感知机制能有效降低任务的平均响应时间.     

寿命服从多元指数分布的树型网格服务可靠性与性能模型

已有网格服务可靠性与性能模型均假设资源节点和链路可靠性服从独立指数分布,这种假设有利于简化建模和分析,但同时也限制了已有模型的应用范围,因为在实际网格环境中,资源节点和链路可靠性存在相关性,即寿命服从多元指数分布.针对这个问题,在已有的树型网格服务模型的基础上,把资源节点和链路的寿命分布从一元指数分布拓展到多元指数分布,提出一种寿命服从多元指数分布的树型网格服务可靠性与性能模型,同时给出该模型的求解算法.寿命服从多元指数分布的树型网格服务可靠性与性能模型求解算法通过构造互斥分解树,把模型求解问题分解成互斥极小项来获得模型的解.实例和理论对比分析表明:寿命服从多元指数分布的树型网格服务可靠性与性能模型不仅兼容已有树型网格服务模型,而且能够适用于寿命服从多元指数分布的树型网格服务计算环境建模,同时寿命服从多元指数分布的树型网格服务可靠性与性能模型求解算法不仅能更有效求解已有树型网格服务模型, 而且可以求解更复杂的多元指数分布树型网格服务模型,与已有网格服务模型求解算法相比具有更强 的通用性和更高的算法效率.     

面向可靠性一费用优化的网格任务调度模型及算法研究

网格资源的异构性、动态性等特征使得网格任务调度仍面临着诸多问题。针对传统可靠性评佑模型仅考虑 资源失效的问题,在考虑本地任务会抢占网格任务执行资源的情况下,引入任务执行延期失效,从而建立了一种新的 网格资源可靠性评估模型。该模型使用随机服务系统理论建模网格资源的动态负载压力,给出了任务在资源上的执 行可靠性的计算方法及证明。基于建立的网格资源可靠性模型,建立了面向可靠性和费用的多目标任务优化调度模 型,以获得最大化任务执行可靠性、最小化任务执行费用的任务调度策略。针对该NP问题,采用化学反应优化算法 对该优化问题进行求解,并给出了算法4种操作的具体实施方法。仿真实验表明,所提出的可靠性评估模型更符合真 实的网格系统,与遗传算法、粒子群算法相比,化学反应优化算法能更好地解决可靠性一费用双目标优化的网格任务调 度问题。     

基于第三方支付的网格资源安全交易模型

网格资源交易中,交易双方都是虚拟的结点,双方对相互的信用情况没有直接的了解,虽然使用信誉值来反映资源提供者的可靠性在一定程度上提高了资源的成功交易率,但无法确保整个交易过程的安全进行.为弥补资源交易中的这种不足,进一步提高资源的成功交易率,参考电子商务中的第三方支付机制,引入第三方对交易过程进行管理与控制,提出了一种新的网格资源交易模型,并对模型中的安全机制进行了详细分析.分析结果表明该模型可以实现安全可靠的交易,保证交易双方的经济利益.     

一种冗余调度的可靠网格计算模型

为了解决动态、不稳定的网格环境下的可靠计算问题,提出一种基于冗余调度的可靠网格计算模型.首先给出计算网格系统可靠性的定义,并基于系统可靠性定义给出了冗余调度的可靠网格计算模型,设计了冗余调度算法,模拟实验结果证明了提出的模型可以提高计算网格任务调度的可靠性.为了使提出的模型更好应用于实际网格计算环境,给出基于概率的冗余度优化公式,将该公式引入到冗余调度模型,可以获得优化的调度冗余度,不仅可以提高任务调度系统的可靠性,而且能提高资源的利用率.     

网格计算经济中资源的可靠性控制

针对网格资源的可靠性问题,提出了一个包括注册真实性,信任评价和调度契约构成的分层控制模型.针对该模型,提出了资源注册信息的验证方法和契约的模式.仿真实验表明,该模型在资源注册信息验证的基础上,优先调度了信息真实、运行可靠的资源,通过可靠性资源的选择和控制促进了计算经济的可靠性.     

基于信任机制的资源调度模型

资源调度模型是计算网格资源管理系统的主要部分之一.当前计算网格中资源调度模型的调度机制和信任机制相分离,忽略了信任的缺失引发的恶意行为会影响到整个网格系统的运行效率和调度安全.定义了域间和域内信任度的计算方法,设计了信任机制模块的调度算法.在分析现有的网格资源调度模型的基础上,增加了安全调度控制模块-信任机制模块,提出了基于信任机制的网格资源调度模型.这样大大地提高了任务调度的成功率,增强了系统的可靠性和安全性.     

一种面向需求的网络服务发现框架

网格服务模型是一个广义的协同工作模型,其固有特征是资源所有者完全拥有资源的支配权.根据这一特征,本文参考市场机制提出了一种面向需求的网格服务发现框架.其基本观念是服务提供方主动查找用户,并提供服务,这与主动服务的观点相吻合.同时可以作为原来需求方查询资源的补充模型.并且资源提供方可以应用该框架进行有针对性的服务开发.文中主要对涉及的相关问题进行了初步的阐述,为今后的研究做铺垫.     

采用遗传-退火算法的网格依赖任务可信调度

针对异构网格环境下的依赖任务调度问题面临的安全性挑战,综合考虑网格资源节点的固有安全性和行为安全性,构建一个网格资源节点身份可靠性度量函数和行为表现信誉度评估策略;同时为了确立任务安全需求与资源节点安全属性之间的隶属关系,定义了安全效益隶属度函数,从而建立了一个网格任务调度的安全可信模型.以此为基础,定义任务需求表示模型和网格资源拓扑模型,提出一种安全可信的网格任务调度新模型.为求解该模型,在遗传算法的基础上,设计新的进化算子即改进的交叉算子、内部交叉算子及作为变异的迁移算子,同时引入模拟退火算法增加搜索精度,从而提出了一种新的遗传-退火算法.仿真实验表明,在相同条件下,该算法比同类算法在调度长度、安全可信值及收敛性等方面具有更好的综合性能.     

时间约束下可靠性增强的网格工作流调度算法

如何在动态性极强的网格环境中有效调度工作流应用并满足用户的QoS需求是一个难题.传统的基于资源静态特征的启发式调度算法或预留策略缺乏对资源动态服务能力的有效评估而无法保证工作流应用的截止时间约束.本文采用随机服务模型建模网格资源的动态性能并考虑资源内处理单元失效的情况.利用生灭过程描述资源节点中处理单元数目的变化情况并给出了资源节点在任务截止时间内的可靠性评估方法.在此基础上,提出一种可靠性增强的网格工作流调度算法RSA_TC.实验结果表明RSA_TC算法相对于DSESAW和PFAS算法,能有效保证用户截止时间的要求,对动态网格环境有较好的自适应性.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

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.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。