无线传感器网络通信性能确定上界研究

无线传感器网络一般具有实时性,其端到端通信性能上界研究具有重要意义.基于确定性网络演算理论,对无线传感器网络为保证实时数据优先的数据转发调度策略进行了性能分析与评价.建立了基于确定性网络演算的端到端通信性能分析模型,经过理论分析得到了无线传感器网络节点的数据队列上界、端到端数据流的延迟上界以及端到端数据流的延迟抖动上界.仿真结果表明基于网络演算理论的无线传感器网络性能上界均在理论计算的上界范围之内.本文的研究使得对无线传感器网络通信性能的研究更符合完备性的要求.     

蓝牙无线传感器网络近饱和组网方法

针对蓝牙在无线传感器网络中的应用,提出了一种蓝牙无线传感器网络组网方法,详细地描述了组网过程,并对该方法的性能进行了分析评估。组网方法采用了树形拓扑、近饱和微微网、关键节点备份等机制,具有网络内微微网数较少、网络健壮性较好、生存时间较长的优点。     

无线传感器网络汇聚节点自组织选举协议

无线传感器网络是由能够感知环境信息和能够进行无线通信的传感器节点构成的网络,广泛应用在环境监测、目标跟踪等方面.无线传感器网络中,汇聚节点(Sink)的位置选取关系到整个网络的性能和生命期,并与节点的部署情况、网络的拓扑结构紧密关联.本文对汇聚节点位置对于无线传感器网络性能和生命期的影响进行了分析之后,以全网能耗、平均-最大端到端延迟为权衡指标,设计了汇聚节点选举协议.仿真表明,运行该协议的网络能够以较小的代价,迅速地选举出具备最优权衡指标的Sink,同时网络还体现出优秀的自组织组网能力.     

基于msstatePAN协议栈的无线传感器网络设计

本文介绍一种采用msstatePAN协议栈和嵌入式技术开发的无线传感器网络,重点介绍了msstatePAN协议栈下应用程序的设计,该网络由Modbus TCP无线基站、无线路由和无线传感器节点组成树形拓扑结构,系统传输速率可达250kbps,节点数可达上百个,节点功耗小于10mW,通过增加无线路由通信距离可达几公里,能广泛应用于精准农业、环境监测等领域。     

基于遗传算法的无线传感器网络巡航覆盖最小移动节点数研究

被监测环境的状态可以使用无线传感器网络的有效感知.本文使用无线传感器网络巡航覆盖模型实现了建筑能效监测过程.为降低基于无线传感器网络巡航覆盖模型的数据采集系统构造和维护成本并降低系统复杂度,采用MTSP问题对无线感器网络巡航覆盖最小移动节点数问题建模,提出了无线感器网络巡航覆盖最小移动节点数快速求解算法并使用遗传算法实现了快速求解算法.实验结果表明,本文提出的方法快速有效,而基于遗传算法的快速求解算法的实现可以快速确定无线感器网络巡航覆盖最小移动节点数上界.     

一种ZigBee无线传感器网络节点的设计

通过在研究ZigBee协议的基础上,设计并实现了基于首款单芯片ZigBee解决方案的射频芯片CC2430的一种传感器网络节点,通过在此节点平台上实现ZigBee网络的星形和树形的拓扑结构,并给出了在串口通讯上的结果演示.并为研究大型无线传感器网络提供了一个实验平台.     

多媒体无线Mesh网基于机会路由的网络编码

采用机会路由下无线Mesh网络的链路吞吐量模型,利用确定性网络演算工具,得到无线Mesh网络节点数据积压的上界以及端到端数据流延迟和抖动的上界;然后设计满足多媒体服务质量的确定性网络编码（DNC）,提出ETC作为确定机会路由中编码节点的指标,在节点数据积压未达到上界时,编码节点采用线性网络编码,提高网络的性能;提出ETP作为机会路由中选择候选节点的指标,主要考虑端到端的延迟和延迟抖动确定接收数据的候选集。仿真结果表明可以达到较好的效果。     

基于动态规划的无线传感器网络的路由算法

路由问题是无线传感器网络中的核心问题之一,其数据传送的多跳特点使得非常适合用动态规划的原理来设计传感器网络的路由算法.基于动态规划,通过节点跳数生成算法为传感器网络中的每个节点赋一个表示到Sink点跳数的节点跳数值,并分析了传感器网络的拓扑结构特点,然后给出了无线传感器网络中寻找从源到汇满足不同设计目标的最小跳数(MinH)、最小跳数最大剩余能量(MinHMaxRE)和最小跳数最小费用(MinHMinC)3种路由算法.探讨了最小跳数最小费用路由与最小费用路由之间的关系,并给出了判断最小跳数最小费用路径就是最小费用路径的一个充要条件.算法的能量消耗分析表明,所给路由算法能实现大幅度的能量节省.     

基于线性异构无线传感器网络的协同可靠数据传输

大量无线传感器应用具有线性网络拓扑结构.结合高压输电线路监控系统的层次型异构无线传感器网络架构,提出了骨干网和子网协作进行可靠数据传输,以解决线性拓扑结构的单点失效问题.设计了骨干网节点自适应功率调整机制和传感器节点自动子网切换机制,并在含9个骨干网节点的实验床上实现和性能验证.实验结果表明所提可靠数据传输机制能解决单点失效问题,并能有效改善网络性能.     

基于网络演算的簇树WSN性能上界分析

为保证WSN的服务质量(QoS),需精确求解其性能上界。对进入WSN节点的数据流进行漏桶管制,节点为数据流提供基于速率-延迟模型的服务保障,在已有簇状拓扑WSN性能模型研究基础上,利用确定性网络演算理论推导簇树WSN节点的有效带宽、缓冲区队列长度上界和数据流端到端延迟上界。     

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     

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。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.