无线传感器网络中能量有效自适应路由算法研究

针对无线传感器网络寿命最大化问题,基于无线传感器节点能耗分布特点和数据传输能耗模型,建立无线传感器网络生存周期的数学优化模型,并针对最小能耗路由的能耗不均衡问题和能量均衡路由的能耗开销问题,综合考虑网络中节点的剩余能量和节点间发送数据的能耗,提出一个适合无线多跳传感器网络的自适应路由算法。仿真结果表明,提出的路由算法能充分地利用有限的能量资源,较大地延长网络生存周期。     

无线传感器网络中能量有效自适应路由算法研究

针对无线传感器网络寿命最大化问题,基于无线传感器节点能耗分布特点和数据传输能耗模型,建立无线传感器网络生存周期的数学优化模型,并针对最小能耗路由的能耗不均衡问题和能量均衡路由的能耗开销问题,综合考虑网络中节点的剩余能量和节点间发送数据的能耗,提出一个适合无线多跳传感器网络的自适应路由算法。仿真结果表明,提出的路由算法能充分地利用有限的能量资源,较大地延长网络生存周期。     

无线传感器网络跨层自适应周期分簇路由模型

分析了无线传感器网络传输信息位置相关性特点以及节点能耗模型,运用基于能量指标和距离指标的簇首选举方法,建立了一种基于节点剩余能量和传输距离的跨层自适应周期簇间路由性能模型。该模型均衡网络节点能耗和负载。簇间通信根据其下一跳簇节点的能量、能耗因子、RSSI以及能耗指数等进行选择。仿真结果表明,与已有的跨层设计和分簇协议相比,该模型有效地延长了网络寿命,提高了网络的吞吐量。该模型能效高,控制开销较低,能量负载均衡。     

基于能量选择的ReInForM路由算法研究与仿真

研究网络路由能量优化问题,针对传统的高可靠性路由算法难以均衡能耗的问题,为了实现高可靠性能量优化,提出了基于能量选择的ReInForM路由算法.新算法通过引入节点能耗量化评估机制,将邻居节点集合中待选节点按能耗进行排序,在保证传输可靠性的前提下,优先选择能量消耗少,剩余能量多的节点,从而优化路由算法.新算法解决了在恶劣通信环境下,高可靠性路由算法的能耗均衡问题.仿真验证了新算法在均衡路由能耗,减少失效节点个数,延长网络生存时间方面取得了较好的效果.新算法较传统算法取得更好的效果.     

无线传感器网络能耗均衡路由模型及算法

在综合考虑传感器网络中节点链路接入、数据包传输能耗及节点剩余能量的基础上,提出了一种自适应能耗均衡路由策略,并给出了相应的数学最优化模型及求解算法.优化的目标是均衡网络能耗,进而最大化网络寿命.首先采用跨层分析的方法设计了符合传感器节点计算能力的分布式动态路由树生成算法及各节点的路由选择策略函数;然后通过构造一个双层规划模型使传感器网络的整体能耗趋向均衡,尽可能地延长网络寿命.一个数值例子说明,提出的路由选择策略、双层规划模型及求解算法是可行且有效的.     

能量高效的水声传感器网络多跳非均匀分簇算法

针对现有水声传感器网络(UW-ASN)分簇路由算法存在的能耗不均衡问题,提出了一种能量高效的多跳非均匀分簇(EEMUC)路由算法。通过节点到基站的物理距离建立网络非均匀分层模型,各层区域内的节点根据综合属性值选择簇头,靠近基站的簇的规模小于远离基站的簇。簇间采用多跳路由方式传送数据,从而均衡了簇头的能耗。实验结果表明,所提算法在簇头数目和节点的剩余能量等性能方面优于低能耗自适应分簇路由(LEACH)和能量高效的非均匀分簇(EEUC)算法,从而提高了水声传感器网络的能量效率,并延长了网络的生命周期。     

基于簇的能量均衡无线传感器网络时间同步算法

针对现有时间同步算法应用于多跳无线传感器网络时存在的误差累计和能耗不均衡问题,提出一种基于簇的能量均衡时间同步算法。该算法基于簇状分层的网络拓扑,簇首之间采用双向监听机制代替双向交换机制,以减小通信开销和发送时延带来的同步误差;簇成员节点利用双向交换和单向广播相结合的机制与簇首同步,并通过最优剩余能量选取回应节点,均衡簇内节点能耗。对提出的新方法和传统的同步算法在精度和能耗方面进行理论分析和仿真验证,结果表明,该算法在保证较高同步精度的前提下可以减小通信开销,均衡网内节点能量消耗,延长网络生命周期。     

WSN中基于最大最小化的优化路由算法

无线传感器网络(WSN)由能量受限的节点组成,需要设计路由算法优化节点的能耗。文章以最大化网络生存时间为目标,基于最大最小化模型提出了优化路由算法,定义了数据发送矩阵,设计了转发节点选择机制,以避免路由回路;基于节点收发数据的能耗及剩余能量,设计了求解优化路由的数学规划模型,优化了传感器节点的数据发送路径和发送量,均衡了节点的能量消耗。仿真结果表明,该算法能有效地均衡节点的能耗,延长网络生存时间。     

一种应用于机场廊桥监控网络的路由算法

针对民航机场廊桥监控网络在机场停机坪现场测试中暴露的网络节点过早死亡、网络生命周期短的问题,对该系统无线网络架构中路由层算法进行优化,采用基于剩余能量和位置的改进LEACH算法,根据网络环境的因素综合考虑节点剩余能量、网络平均剩余能量以及节点位置,分步选出最优簇头,同时,采用能量估算方法确定网络平均剩余能量,达到均衡网络能耗且延长网络生命周期的目的.最终利用Matlab软件对民航机场廊桥监控管理系统建模仿真,仿真结果表明：提出的算法比网络原有路由层LEACH算法在均衡网络能耗和提高网络生命周期上均具有优越性.     

基于改进蚁群算法的无线传感器网络路由的优化

为了延长无线传感器网络(wireless sensor network,WSN)的生命周期,均衡各个节点间能量消耗,针对现有的WSN路由优化算法存在的问题,提出了一种基于改进蚁群算法的路由优化算法;首先通过对蚁群算法和遗传算法的优劣性比较,在蚁群算法的基础上,结合遗传算法的选择、交叉和变异的操作,从而提高蚁群算法的搜索速度和寻优能力;最优路径评价函数综合考虑节点能耗及节点的剩余能量,使剩余能量多的节点优先参与数据转发,均衡节点间的能量消耗;通过与经典蚁群算法及遗传算法的对比实验表明,随着数据转发轮数增加,改进的蚁群算法能耗小,剩余能量多,网络生命周期明显延长;随着整个网络运行时间的增长,改进的蚁群算法,节点均衡能耗性好,最优路径搜索的成功率也明显优于其他两种算法。     

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.