WLAN场景下移动网络IPv6的演进方案

随着物联网的兴起和移动数据业务的增长,在移动网络中引入因特网协议第六版(IPv6)成为大势所趋.同时无线局域网(WLAN)作为移动网络补充接入手段,用于解决在热点地区分流数据业务的问题,越来越受到运营商的重视.首先分析了终端的兼容性,其次介绍了WLAN接入的网络架构,提出了一个在WLAN接入场景下的IPv6演进方案,优...     

基于IPv6的无线传感器网络的一种节点自组织成网算法

本文从无线传感器网络接入下一代互联网的互连方式出发,论证了全IP方式在单兵系统——空降兵系统的可行性;然后利用IPv6协议——无状态地址自动配置协议和移动IPv6协议,提出了在空降兵跳伞成功后或者有单兵移动时的一种自组织成网算法;最后用实验仿真验证了传感节点中实现的无状态地址自动配置协议的正确性。     

IPv6 WLAN安全网关设计

IPv6强大的寻址方案和对移动性的支持,使其在WLAN中的应用成为一种趋势。WLAN为用户提供了便捷接入的同时,也带来相较于有线网络更大的安全威胁,IPv6的邻居发现协议和自动配置功能等这些特点使得WLAN的接入安全变得更为复杂。设计一个IPv6 WLAN环境下的安全网关,能够检测到网络中潜在的漏洞和威胁,通过搭建实验环境,并对未授权接入、DAD DOS攻击和重定向攻击三种安全威胁进行了仿真,实验结果证明该安全网关的有效性。     

基于IPv6的无线传感器网络接入设计*

无线传感器网络(WSN)与现有网络基础结合是WSN研究中必须解决的技术问题之一。在IPv6协议下,提出了一种大规模无线传感器网络接入国际互联网方式。本接入方式以数据应用为中心,按地理位置为无线传感器网络映射IPv6地址,由此设计了一种基于地理位置信息的顺时针逐格CGRP路由协议,并通过仿真实验分析协议的稳定性和路由分组传输成功率,最后阐述了以网关为路由接口的无线传感器网络与Internet通信机制。该接入方式既能根据IP对无线传感器网络寻址,又能降低无线传感器网络全IP化带来的高额开销,符合无线传感器应用     

6LoWPAN接入互联网的自适应联合网关的设计与实现

无线传感器网络与互联网结构的差异使得两者在接入与数据包处理等方面都面临着一定的技术难点。针对基于IPv6协议的低速无线个域网6LoWPAN( IPv6 over Low Power Wireless Personal Area Network)与互联网接入方式的问题,用无线射频接入方式代替串口通信方式,提高通信过程中通信速率。同时结合无线传感器网络技术、嵌入式技术、轻量级网络地址转换/协议转换技术uNAT-PT(Micro Network Address Translation-Protocol Translation)、站间自动隧道寻址协议技术ISATAP(In-tra-Site Automatic Tunnel Addressing Protocol)和进程间通信IPC( Inter-Process Communication)机制,在网关处实现了两者之间的自适应适配互通机制,优化数据包流向问题。实验结果表明,无线射频接入方式与协议适配的自适应数据包调度机制能够提高通信过程中的通信速率,减少网络时延,优化网关通信性能。     

移动IPv6网络基于身份签名的快速认证方法

接入认证对移动IPv6网络的部署和应用至关重要,在切换过程中加入认证过程会影响移动IPv6网络的切换性能.当前,对移动IP网络中接入认证的研究大多没有考虑对切换性能的影响.另外,目前许多双向认证机制都是基于证书的方式来实现,无线移动环境的特殊性使得这种方式并不适合无线移动网络.一种适用于移动IPv6网络的基于身份签名的快速双向认证方法被提了出来.该方法使用NAI(network access identifier)作为公钥,简化了无线移动环境中的密钥管理问题,有效地解决了基于PKI(private key     

嵌入式设备中IPv6地址自动配置的实现方法

在嵌入式技术领域中,支持IPv6的嵌入式设备将是一个崭新的发展方向,地址自动配置是嵌入式设备基于IPv6网络互联的关键方式之一.本文探讨了无状态和有状态两种自动配置方式的运作机理和过程,在嵌入式协议栈中设计并实现了两种地址的自动配置.     

IPv6/IPv4双协议栈以太网接入认证和移动技术

介绍了IPv6/IPv4双协议栈以太网接入路由器及其接入方案具有用户认证、用户管理和详细的数据统计功能,能够同时提供IPv6和IPv4接入,与移动家乡代理服务器配合,可支持移动IP用户,能够满足未来商业化的、有线无线一体化的以太网接入的需求。     

无线传感器网络接入IPv6网络方式的研究

无线传感器网络与IPv6网络的接入方式研究是一个研究热点。从研究代理接入方式和直接接入方式出发,讨论使用直接方式接入IPv6网络的全IP方式,结合单兵作战系统对其做分析。指出全IP接入方式是实现WSN与IPv6网络互联的一种非常重要的思路,对于未来信息化战争具有重大的军事意义,值得进一步展开深入研究。     

我国WLAN建设思路探讨

随着中国电信市场的进一步开放以及宽带市场的逐步成熟，近几年国内各大运营商都在进行WLAN建设。WLAN作为有线接入方式以及低速无线接入方式的良好补充，越来越受到国际和国内电信行业的重视。在热点地区部署WLAN节点进行宽带多媒体业务的接入，是各大运营商挺进宽带数据多媒体业务市场的手段之一。WLAN的建设有利于提高各大运营商在复杂的竞争环境中的生存能力。     

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.