用可分负载理论分析无线传感器网络任务调度

针对无线传感器网络的任务如何在最短时间内完成且充分利用网络资源的问题,提出了一种基于可分负载理论的无线传感器网络任务调度算法（WDTA）.该算法根据网络中各个节点的处理能力和节点间的通信能力,将总任务从SINK节点下发至网络中.通过去除节点间的通信干扰来提高资源利用率和减少总任务完成时间.算法在两种分群结构的异构网络环境下进行了分析,得到了在各个节点上最合理的任务分配方案,以及最短的任务完成所需时间.理论分析了基于可分负载理论的无线传感器网络任务调度的极限情况.实验结果表明WDTA算法能够通过合理分配任务,而减少任务完成时间及节点能耗.该方案可以作为设计大规模无线传感器网络的原则.     

能量有效的无线传感器网络动态任务调度算法

为减少无线传感器网络任务调度的能量消耗,平衡网络负载,提出能量最小化的动态任务调度算法。在感知动态环境的基础上,将传感器网络节点的覆盖率、可调度性等作为该问题的约束条件。将改进后的蚁群算法应用于任务调度算法中,通过迭代得到最优分配方案,引入信息熵提升剩余能量充沛的节点执行任务的几率。仿真结果表明,该算法在降低任务分配的执行时间、能量消耗量及优化网络负载平衡方面取得了较好的效果。     

基于改进NSGA-Ⅱ的无线Ad-hoc网络任务调度算法

针对无线Ad-hoc节点的移动性和易失效性导致的任务完成效率降低的问题,提出了一种无线Ad-hoc网络任务调度的多目标优化算法(MOTA).该算法在追求最短的任务完成时间的同时,还考虑到节点的失效概率和能耗.它避免将任务分配到失效率较高的节点上执行,从而有效地降低了节点的失效对任务执行的影响.仿真分析表明,该算法能够有效地平衡任务完成时间最小化、任务完成概率最大化及能耗最小化的目标.与传统任务调度算法相比,其仿真实验取得了更好的结果.     

无线多媒体传感器网络实时任务分配算法

为了满足多媒体信息传输的时延、同步的要求,提出无线多媒体传感器网络(Wireless Multimedia Sensor Networks,WMSNs)在能量受限情况下的实时任务分配算法.根据跟踪目标、传感器节点和汇聚节点的地理位置信息分簇,簇内节点任务分配选择能够满足能量上限的调度长度最小的分配方案.调节任务执行能量上限Emax、合作处理分簇的最大跳数K和执行任务总数Tnum三个参数,随机产生任务图进行仿真实验.结果表明:在性能上,算法满足节点能量受限的要求,在实时性方面有明显改善,与早期的分布式计算架构相比,由仿真图估算可得任务调度长度减少约45%;与带能量限制的任务映射和任务调度算法EcoMapS相比,从仿真图可以看出,任务调度长度也有明显减少.     

智能建筑室内环境分布式可计算WSN任务调度研究

针对智能建筑室内环境下并行计算的动态任务调度问题,构建了基于分布式CPS思想的无线传感器网络(WSN)模型,并分别设计了基于可计算复杂性的任务分配策略和基于动态调度算法的任务调度策略。通过先将任务分配成若干个子任务,采用多带图灵机输入任务,由合适的计算节点进行计算,形成有向无环图,再按调度优先级排列任务,形成任务调度序列表,依序处理任务,从而达到了将任务分配、调度和执行相结合的目的。实验结果表明该策略可有效减少智能建筑室内环境分布式可计算WSN分布运行时任务之间的通讯时间和等待时间,同时提高了任务调度的成功率,最终优化系统的运行效率。     

基于Q学习和规划的传感器节点任务调度算法*

为了改善节点的学习策略,提高节点的应用性能,以数据收集为应用建立任务模型,提出基于Q学习和规划的传感器节点任务调度算法,包括定义状态空间、延迟回报、探索和利用策略等基本元素.根据无线传感器网络(WSN)特性,建立基于优先级机制和过期机制的规划过程,使节点可以有效利用经验知识,改善学习策略.实验表明,文中算法具备根据当前WSN环境进行动态任务调度的能力.相比其它任务调度算法,文中算法能量消耗合理且获得较好的应用性能.     

GPU/CPU异构系统任务节能调度方法仿真

研究GPU/CPU异构系统任务调度的节能问题.与传统同构体系结构相比,异构系统任务调度呈现较大的随机性和不定性,GPU/CPU异构系统中时间间隙片段呈现了较大的随机性,导致传统调度方法很难建立规则的描述时间片段的模型,调度能耗较高.为解决上述问题,提出了一种改进功耗优化的GPU/CPU异构环境下的任务调度算法,将任务关系图按照依赖关系计算量拆分,并分配到计算节点.在计算节点内根据权重法的思想,统计所有计算节点的处理情况,进而将节点内的子任务调度到合适的处理器.实验结果表明,在不影响应用性能的前提下,降低了异构系统的能耗开销,优化效果明显.     

云环境下基于强化学习的多目标任务调度算法

针对云计算环境下的多目标任务调度问题,提出一种新的基于Q学习的多目标优化任务调度算法(Multi-objective Task Scheduling Algorithm based on Q-learning,QM TS).该算法的主要思想是:首先,在任务排序阶段利用Q-learning算法中的自学习过程得到更加合理的任务序列;然后,在虚拟机分配阶段使用线性加权法综合考虑任务最早完成时间和计算节点的计算成本,达到同时优化多目标问题的目的;最后,以产生更小的makespan和总成本为目标函数对任务进行调度,得到任务完成后的实验结果.实验结果表明,QMTS算法在使用Q-learning对任务进行排序后可以得到比HEFT算法更小的makespan;并且根据优化多目标调度策略在任务执行过程中减少了makespan和总成本,是一种有效的多目标优化任务调度算法.     

基于数据局部性的推测式Hadoop任务调度算法研究

针对Hadoop平台现有任务调度算法优化程度不高的问题, 提出了一种基于数据局部性的推测式任务调度算法。该算法通过计算节点上Map和Reduce任务时长比例, 结合不同节点上数据的局部特性, 采用了比现有算法更精确的任务进度探测方式找出快慢节点, 在快节点上启动剩余时间最长的落后任务的备份任务, 用移动计算代替移动数据。在Hadoop环境中进行了实验, 结果表明该算法比现有算法缩短了任务平均运行时间, 加快了任务的执行效率。     

基于动态联盟和蚁群算法的任务协同框架

单个节点能力受限,无线传感器节点需要协同完成任务。针对该问题,将协同任务分为感知子任务和计算子任务,提出基于动态联盟和蚁群算法的任务协同框架。根据应用需求选择感知节点形成初始联盟分配感知任务,当感知节点与节点总数的比值小于32%时,网络监测性能最优,引入自适应蚁群算法构建数据汇集路由树,利用同一任务数据的强相关性优化数据传输路径,从而降低通信能耗。     

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。     

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.     

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     

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.     

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.