一种多向链路感知的车载Ad Hoc网络传播协议

为了提高车辆自组织网络（Vehicular Ad Hoc Network,VANET）的数据传输效率,并使车辆间的数据通信能够持续进行,提出一种多向链路感知的车载Ad Hoc网络传播协议。为了保证车辆节点在执行通信任务的过程中实现数据的持续传输,防止通信链路频繁断连影响传输质量,提出了车辆网络的时间关联模型来讨论车辆间的速度差与通信持续时间的关系。为了缩短VANET中用于数据传输任务的总时间,协议基于改进蚁群的方法进行了多向链路感知,从而寻找在保证通信需求时间下的最短传输路径。实验结果分析表明,相比基于改进地理信息路由和基于优化链路状态路由的VANET数据传输算法,该算法的数据传输任务完工时间分别缩短了38.4%和27.3%,平均传输延迟分别降低了25.5%和12.1%。     

基于蚁群算法的无线传感器网络路由算法

提出一种基于蚁群算法的无线传感器网络按需多路节能路由算法.该算法综合了蚁群优化算法和AODV路由协议的思想.通过蚂蚁并行地在源节点和目的节点之间建立多路径路由,提高了网络数据传输的实时性、延长了整个网络的生命期.仿真结果表明.该算法与多种群蚁群优化路由算法、基本蚁群算法相比,在整个网络的生命期和节能方面效果显著.     

基于蚁群系统的WSN能量均衡多路径路由协议

针对无线传感器网络节点能量有限和网络拥塞问题,采用一种基于蚁群系统的能量均衡多路径路由协议。在路由发现过程中,综合考虑节点最小剩余能量和平均剩余能量,通过跨层设计模型获取节点距离信息和节点队列长度作为启发式函数,利用蚁群系统的特点形成多路径的数据传输。仿真结果表明,该路由协议在端到端传输时延和能量均衡等方面优于其它协议。     

基于蚁群优化的能量有效Ad Hoc路由算法

由于传统的Ad Hoc网络路由算法不考虑能量因素,为了改善其能量约束问题,根据自然界蚁群的觅食行为[1]提出了一种能量有效的路由算法.在路由选择过程中综合考虑了路径长度和节点的剩余能量,并且利用蚁群优化的特点形成多路径的数据传输,有效地延长了节点有限能量的使用时间,进而延长网络的生存期.在仿真实验中与现有相关协议进行了对比,结果表明了该算法的有效性.     

城市环境下跨层VANET路由协议研究

车载自组织网络(VANET)单一分层结构路由协议考虑因素较少,导致分组投递率低、端到端时延较高。为此,考虑车辆位置、速度、路口密度、无线链路质量、MAC层误帧率等影响因素,提出一种应用于城市环境的基于位置信息的VANET跨层路由协议(MCLPR)。设计路口车辆节点选择算法提取无线链路质量和MAC层误帧率的跨层信息,采用层次分析法计算各影响因素的权重值,确定最佳转发路径。仿真结果表明,与AODV,DSDV等路由协议相比,MCLPR路由协议具有较高的分组投递率及较低的端到端时延,保证了数据传输的可靠性与高效性,适用于网络密度与负载较大、车辆移动速度较快的城市环境。     

方向和位置泛洪的车联网区域路由协议

为提高车载自组网路由发现、数据传输效率,对区域路由协议进行改进。考虑到车载自组网（VANET）通信环境（道路布局、方向、位置等）多样性,通过判断节点间位置关系缩小泛洪区域,下一跳优先选择该区域内与源或目的节点移动方向相同的节点,进一步减少转发节点数目,以此精细化限制泛洪。为适应 VANET 拓扑频繁变化链路脆弱特性,目的节点优先选择相同移动方向节点数最多,且平均邻居节点数最多的链路,保证数据可靠传输。仿真结果显示：改进方案较好地克服了原协议全向洪泛引起的网络开销大、单一跳数路由选择导致的丢包率、重传率较高等缺点,能够较好地适应 VANET 网络通信。     

采用角度因子的蚁群优化多路径路由算法

为均衡能量消耗、提高数据传输的可靠性,提出采用角度因子的蚁群优化多路径路由算法（ACOMP）。在密度递减节点部署策略的基础上,为避免能量“热区”,优化蚁群算法进行多路径搜索,搜索过程加入节点间的角度因子进行路径方向引导。基于对选出的各较优路径实时能量的感知,建立多路径决策模型,使得源节点可以选择当前性能最好的路径进行较可靠的数据传输。同时为避免路由空洞,定义修复蚂蚁并结合反馈机制使得路径保持良好状态。仿真结果表明：提出的算法可以实现节能、可靠的路由,并可均衡整个网络的能量消耗。     

无线Ad Hoc网络中增强安全性的多路径路由算法

针对无线ad hoc网络的数据安全性问题,提出了一种增强安全性的多路径路由算法．该算法通过目标节点发送检测数据包的机制,动态维护多路径路由信息的有效性．源节点则根据收到检测包的信息自适应地更新当前的最优传输路径,充分利用路由寻找及维护过程中的信息建立多条可用路径,提供最优的路由方案,并增强了无线ad hoc网络数据传输的安全性．仿真结果表明此算法的数据传输安全性达到了合理的水平．     

移动边缘计算环境下基于改进GPSR的VANET路由算法

针对车辆自组织网络(VANET,vehicular ad-hoc network)中现有路由协议存在的路由选择错误、丢包率较高、服务质量低等问题,提出了移动边缘计算环境下,结合改进贪婪周边无状态路由(GPSR,greedy perimeter stateless routing)和自适应链路质量评估的VANET路由算法;首先,结合边缘计算构建了VANET通信模型,对其车辆位置和速度进行系统的理论分析;将边缘计算架构应用于VANET能够有效缓解计算量大、与车辆有限且不均的资源分布之间的矛盾;然后,提出了基于节点移动速度和节点间距离的改进GPSR协议,通过自适应链路稳定性和链路传递速率评估来选择合适的中继节点,动态更新链路;通过SUMO仿真平台对路由算法的性能进行评估,实验结果表明,相对于其他算法,所提算法受车辆密度、交通流以及车辆相对速度的影响较小,且提高了分组传送率(车辆数为300时传送率达到92%),减少端到端延迟(交通流为5时延迟降低到1.5 s),从而降低了通信开销。     

移动无线传感网的移动感知路径选择算法

为解决稀疏网络环境下移动传感节点的区域全覆盖和数据传输问题,提出一种移动无线传感网的移动感知路径选择算法(MSPS)。在MSPS算法中,用数学公式表示邻居网格集合、区域覆盖率、数据传输时延、节点平均能耗等参数。采用机会路由算法进行数据传输,并建立能保证全覆盖监测区域且权衡数据传输时延、数据传输率和节点平均能耗的移动路径选择优化模型。提出到目标网格的路径寻找方法、初始染色体的确定方法和染色体适应度值计算方法。最终提出修正的多种群遗传算法求解优化模型,获得移动传感节点的最优移动方案。仿真结果表明:不管监测区域内是否存在障碍物,MSPS算法都能提高数据传输率,降低数据传输时延和节点丢弃的总数据量。在一定的条件下,MSPS算法比SGA、TCM_M、RAND_D和RAND算法更优。     

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.