无线网状网技术研究

无线网状网是一种新兴的无线局域网技术。通过分析无线局域网的现状,详细讨论了无线网状网的功能特点,同时对比几种厂商的无线网状网解决方案,对无线网状网的组网方式和实现方式进行了探讨。研究工作为无线网状网的设计提供了良好的技术依据。     

“无线网状网”在校园

无线网状网是对无线局域网技术的一种创新。它支持宽带和一定的移动性,目的不是为取代漫游的移动电话服务。无线网状网属于局域网,能以较高的性价比,覆盖较大的城市区域。     

无线网状网 网住校园

无线网状网是一种全新的、灵活的广域WLAN解决方案,能够在某一地区实现无线局域网的扩展与延伸,并提供室内外的安全无线接入覆盖。     

无线网状网与应用技术

无线网状网是一种新兴的无线组网技术并且具有良好的市场需求。该文首先简要介绍了无线网状网的产生和发展,然后针对无线网状网的定义特点关键技术以及应用前景等核心问题,进行了初步的探讨和总结。     

IEEE 802系列无线网络网状组网与移动切换技术综述

传统的无线区域网络在进行大规模应用时受制于网络灵活扩展和对快速移动的支持。IEEE 802的相关标准组正在致力于推动网状组网和快速移动性支持方面的技术进步,制定相关的技术标准。以802.11s、802.15.5和802.16/20为例讨论了基于无线局域网、无线个域网和无线城域网的网状网技术与移动性支持技术。介绍了无线区域网络的发展趋势和技术路线,为更好地推动无线多跳网络的研究与应用奠定基础。     

无线局域网技术在港口通信中的研究与应用

无线上网是无线数据传输应用最广泛、最基本的一种模式，其中作为有线网络延伸和扩展的无线局域网技术越来越得到重视。本课题基于秦皇岛港通信网的现状，结合港口生产的实际需要，以流动机械分公司为例，对无线局域网进行了研究与建立，包括无线局域网所采用的主要技术、协议标准、安全机制以及与有线网络的互联等。     

WMN的网络安全威胁及路由安全策略研究

无线网状网(WMN)是目前应用比较广泛的一种网络技术,但其面临的网络安全环境日趋复杂。文章着眼WMN面临的网络安全威胁,分析了当前无线网状网应用过程中面临的路由破坏攻击和资源消耗攻击两种类型共七中典型的网络安全威胁,同时,针对无线网状网应用过程中的威胁形式,从密码和检测两个方面介绍了     

无线Mesh网关键技术分析

无线网状网(Wireless Mesh Network,WMN)技术是一种具有良好市场应用前景的新型宽带无线网络技术。本文首先讨论了无线网状网的研究背景,并针对其结构特点、与其他通信网络的区别以及关键技术,进行了初步的探讨和总结。     

骨干无线网状网的排队延迟性能研究

对一种基于网状分布的骨干无线网状网的延迟性能进行研究.提出了一种基于均衡负载的最短路径路由协议.在此协议基础上,研究了无线网状网数据包的排队延迟,推导出无线网状网排队延迟与网络的规模、网关和网状路由器的服务能力、数据包到达率的相互关系.此外,还分析排队延迟和网络容量的相互制约关系,并给出了在延迟限制条件下的网络容量.     

基于VPN技术的安全无线局域网的构建

在无线局域网的设计和部署中,安全是一个关键的问题。现有802．11设备主要采用的安全技术——WEP、802．11X,在设计上存在着安全缺陷,不能很好地保护无线局域网的安全。该文提出了一种将VPN技术应用于无线局域网中的网络部署方案,并研究了其中VPN网关的系统设计方案。     

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.