无线网络的构建和安全策略研究

随着现代化通讯工具的发展,人们对通讯设备之间互联互通的需求日益增加.目前许多通讯设备都是基于某种特定的技术规格设计和生产的,是独立的,它们往往只能和其配套的伙伴产品相互兼容,而无法与其他设备互联互通.近来一些公共场所开始提供无线局域网服务,但如果用户使用的无线网卡和这些场所的设施不兼容,就很可能无法享受这些便利的通信服务.无线局域网络能利用简单的存取构架让用户随身、随时、随地获取信息.文中主要讨论现在流行的无线局域网的构建、调试和维护,并介绍WLAN技术及在智能小区网络应用中的设计方案.详细说明无线网络的安全防护和维护,无线访问控制和安全解决方案的实施.     

无线局域网络中的安全技术(下)

WEP的安全性分析 WEP加密算法是用于向无线局域网提供一种安全程度仅相当于没有加密的有线LAN。对有线LAN传输电缆的物理访问是受限的,因为一般情况下外部人员无法接近这些电缆,而且即使可以接近这些电缆,也很容易被发现。然而,无线局域网使用的无线信道对任何人都是开放的,配备兼容接收机的入侵者只要在无线局域网的有效范围内就可以窃听无线通信信息(如果没有采用WEP),甚     

多元化无线局域网网络安全攻略

安全问题始终是无线局域网的软肋,一直制约着无线局域网技术的进一步推广。从无线局域网技术的发展来看,人们一直都致力于解决无线局域网的安全问题。了解无线网络的安全进程,有助于用户采取有效的安全措施。     

基于PPPoE的无线局域网安全和认证

在IEEE802.11无线局域网中,WEP协议存在问题,不能有效保证用户数据的安全;认证机制过于简单,无法区分单个用户。提出将PPPoE(PPP Over Ethernet)协议作为无线局域网的接入方案。给出了PPPoE在无线局域网中的部署方案。针对无线局域网的特点改进了PPPoE协议。使用动态会话密钥保证了数据的安全。     

802．11g提升无线标准

自1997年IEEE发布了无线局域网802．11标准，无线局域网就开始备受关注，随着技术的发展，标准不断完善并开始分化以满足不同用户的需求。802.11b、802．11a、802．11g(草案)直运而生。它们的同时出现迎来了无线区域网的真正应用高峰。但这样也给用户带来了几个现实问题，什么样的标准适合什么用户?不同标准网络之间如何兼容?     

浅谈无线局域网的安全与维护

随着无线网络技术的发展,无线局域网越来越多的应用到家庭和企业等各种场合,该文介绍了无线局域网安全技术,并对无线局域网的安全维护提出了相应的措施和建议。     

无线办公网络指南

企业无线局域网与家庭无线网络有着诸多不同，安全、高效是每个企业网络用户最为重视的要点。很多无线厂商都推出了面向企业用户的无线网络产品，这些设备与家庭或小型SOHO网络所使用的无线局域网产品有着很大的不同，在安全、性能以及稳定性上，企业级产品有着很大的优势，你在购买设备时一定要分清产品的类型。[编者按]     

企业网络走向无限

企业无线局域网与家庭无线网络有着诸多不同,安全、高效是每个企业网络用户最为重视的要点。很多无线厂商都推出了面向企业用户的无线网络产品,这些设备与家庭或小型SOHO网络所使用的无线局域网产品有着很大的不同,在安全、性能以及稳定性     

企业无线局域网安全方案研究

在国家高度重视网络信息安全的大背景下,建设安全的企业无线局域网,避免使其成为黑客进入企业内网的捷径。文章首先调研分析了无线局域网黑客攻击技术与安全防护技术,然后研究设计了企业无线局域网安全方案并开展安全评测,最后从用户接入、基础设施和安全防护等三个方面总结提出了企业无线局域网安全方案建议。     

研究基于RFID技术的无线网络安全

近年来无线网络的广泛应用,对无线网络服务器的安全提出更高要求.要让用户用上安全便利的无线网络,则无线加密技术,无线射频技术及无线网络服务器的安全管理等都是要讨论的课题.从无线局域网的应用结构、无线射频技术原理,通过对射频技术的管理和强大的RF规划,使每个AP都能在最佳的无线信道上用最合适的发射功率提供服务,提供流量与用户数的控制,分析了无线加密机制.利用不断改进的新技术使得无线局域网技术更加成熟与完善.     

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.