基于生命期预测的移动Ad hoc网络多径路由策略

在移动自组网中,由于网络节点的移动性和拓扑结构的多态性,多路径路由在稳定性,均衡负载方面优于单路径路由,非常适合Ad hoc网络。考虑到移动自组网中节点能量的局限性,在DSR协议的基础上提出了一种新型的多径路由算法。该算法结合节点路径的能量消耗率,预测出链路的生命期,以求找到多条有效路径并进行传输。仿真结果表明,该协议比DSR具有更好的吞吐量和端到端延迟。     

基于干扰感知的无线自组网多播机制

在采用网络编码的无线自组网多播场景中,为了有效地克服节点密度较大时干扰对多播整体性能的影响,提出了一种衡量路径干扰情况的路由度量标准。基于该度量标准,对网络编码机会和节点间干扰避免进行了均衡处理,构建出一种基于部分网络编码的无线自组网干扰感知多播路由机制。仿真结果表明,该机制在能耗、延时和吞吐量等性能方面均优于基于传统网络编码的多播方案,因此特别适用于节点密度较大的场合。     

Ad hoc网络中一种带预测的路由算法

在自组网中,由于网络节点的移动性及拓扑结构的易变性,设计稳定的路由成为最受关注的问题。根据可靠性为多路径路由选择更多的可靠路径,以满足自组网中多路径传输在路径的数量和质量方面的需求,是多路径路由技术中的一个重要研究课题。为此,基于GRID模型和预测模型提出了一种带预测的稳定不相交备用路由算法,其利用有效限制路由查询包的泛洪区域,并结合预测策略和节点不相交路径算法来选择一条最稳定的不相交备用路由,从而进一步提高该路由算法的性能。模拟结果显示,与其他3个多路径路由相比较,该算法是一个有效的自组网路由算法。     

Ad Hoc 网络中基于节点相关因子的多路径路由算法

针对Ad hoc多径路由网络中各路径相互干扰的问题,提出了一种基于节点相关因子模型的多路径路由算法（AOMDV-LR）。该算法利用中间节点能够监听邻近节点接收报文的特性,结合邻近节点路由请求包数量的信息来计算每个中间节点的相关因子,得到总相关因子最小的节点不相交路径,保证各路径的数据传输干扰程度为最低。仿真结果表明,AOMDV-LR算法能显著增加数据包的投递率,降低端到端的传输时延。     

水声传感器网中基于网络编码的多径路由协议

针对水声传感器网通信带宽低、节点能耗高的特点,提出一种基于网络编码的多径路由协议。该协议在路由过程中通过在主链路和后备链路之间动态切换创造更多的网络编码机会进行数据传输,从而优化网络带宽利用率,并降低冗余数据包重传造成的能量消耗。仿真结果表明:基于网络编码的多径路由协议可以在提高水声传感网吞吐量的同时,有效降低网络能量消耗。     

稠密自组网的网关选举策略

自组网是没有固定设施的临时无线系统．已经有多种路由算法被提出．因为自组网的网络拓扑动态改变且带宽有限,路由应当是可扩展且高效的．基于簇的算法是最有效和可以扩展的,然而,它不能有效地处理高密度网络环境．为了减少冗余广播以缓解该问题,该文给出了在高密度节点的网络环境下,存在隐藏网关的可能性定理,提出网关选举算法并证明了其正确性．仿真结果表明,在保证广播成功率的情况下,该方法可以有效地节省重播包比率和广播等待时间。     

基于非均匀分簇机制的ZigBee混合路由算法

针对现有ZigBee网络路由算法存在节点能量消耗不均衡问题,在树路由算法与无线自组网按需距离矢量路由改进(AODVjr)算法的基础上,提出一种基于非均匀分簇机制的ZigBee混合路由算法。该算法将网络分成若干个非均匀的逻辑簇,使距离协调器越近的簇规模越小,从而减少转发任务,使得能量消耗均衡。在分簇的基础上,将节点之间的传输分为簇内传输与簇间传输。簇内传输采用基于邻居表的树路由算法;簇间传输在基于树路由算法无效的情况下,采用AODVjr算法,找到两个簇首之间的较短路径;同时规定只有簇首节点和网关节点才能广播请求分组(RREQ),可以减少冗余的RREQ分组。仿真结果表明,该算法能有效推迟死亡节点出现的时间,延长网络的生存周期,达到提高网络性能的目的。     

一种基于传输容量控制的DTN动态分段编码路由算法*

针对时延容忍网络（DTN）中基于动态分段编码的路由算法DSNC存在的数据冗余编码和节点投递成功率低的问题,提出了一种基于传输容量控制的DTN动态分段编码路由算法NC-TCC。在源节点处,采用AONT矩阵对分段中的数据包进行编码,以减少数据重复编码的次数;在中间节点处,利用构造的节点运动模型计算当前连接的传输容量,并在满足传输容量的前提下按照优先级从高到低的顺序选择合适数量的数据包进行编码,以提高节点投递成功率。仿真结果表明,提出的算法能够有效地减少数据冗余,提高传输效率。     

基于函数逼近的强化学习FANET路由优化算法

针对高速移动状态下的飞行自组网路由协议链路维护困难问题,提出一种基于强化学习的自适应链路状态路由优化算法QLA-OLSR。借鉴强化学习中的Q学习算法,通过感知动态环境下节点邻居数量变化和业务负载程度,构建价值函数求解最优HELLO时隙,提高节点链路发现与维护能力。利用优化Kanerva编码算法的状态相似度机制,降低QLA-OLSR算法复杂度并增强稳定性。仿真结果表明,QLA-OLSR算法能有效提升网络吞吐量,减少路由维护开销,且具有自学习特性,适用于高动态环境下的飞行自组网。     

无线Mesh网中网络编码感知的低时延路由

网络编码技术可以显著提高无线Mesh网的传输性能.为此,提出一个在组播通信中基于网络编码的无线Mesh网低时延传输路由.文中引入了关键节点和超关键节点的概念和相应的选取算法.该协议以下一跳的节点是否是超关键节点或关键节点作为路由判据,下一跳的路由节点优先选择超关键节点,其次选关键节点,最后才选普通节点,这样可以增加网络编码机会,实现低时延路由.通过举例、性能分析和仿真实验表明,该协议能更好地支持网络编码,在提高组播吞吐量的前提下,显著减少了传输时延.     

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.