ISDN的技术热点和发展前景

概述宽带综合业务数据数字网ISDN的基本概念及发展,ISDN的协议和网络结构,技术热点AMT,说明ATM技术的主要优越性,对宽带业务网发展前景作了展望,以及对ISDN的应运前景。     

宽带及其DSL技术解析

在ISDN逐步取代传统Modem的同时，又一种数字用户线路DSL脱颖而出，宽带网络已是显山露水。文章从认识宽带入手，对DSL宽带尤其是新一代的EDSL技术及其应用进行了全面解析。     

宽带综合业务数字网技术

本文介绍了宽带综合业务数字网（B－ISDN）的定义和可提供的业务，探讨了实现B－ISDN的技术难题，文章通过对世界上一些B－ISDN试验情况的介绍，综述了B—ISDN的发展趋向。     

方正宽带技术家用电脑面世

方正电脑公司近日发布了国内第一款基于ISDN宽带技术的方正卓越3000家用电脑和基于ADSL宽带技术的方正卓越6000家用电脑。方正电脑卓越3000-ISDN系列是专门为中国ISDN用户量身定制的家用电脑产品。该产品可以帮助用户在普通的电话线上进行全数字通信业务,并且不需要再另外购买安装复杂的ISDN专用设备,     

宽带网络技术

在窄带ISDN成熟的80年代，考虑到未来技术的进步和对宽带业务的需求，电信界开始寻求一种宽带的、独立于业务的网络。这种网络要能提供高于一次群速率的业务，要能适应从低速到高速各种业务的传送与交换，做到整个网络资源共享。在80年代后期，国际电联正式提出了宽带ISDN（B-ISDN）的概念。B-ISDN的发展目标是以一个综合的、通用的网络来提供全部现有的和将来可能有的业务。为此需要开发新的信息传送技术，而人们在研究、分析了各种电路交换和分组交换技术之后，认为快速分组交换是唯一可行的技术。国际电联于1988年正式把它命名为…     

2003年第3期精彩预告

宽带使用指南从拨号网络到ISDN，从ISDN到ADSL，短短的两三年里，越来越多的人已经告别窄带连接进入宽带世界。然而，不论是使用习惯，技术特点，还是资源利用方式，窄带和宽带都有着天壤之别。原先在窄带连接上盛行的手段、经验，可能在宽带世界就不那么有效了，在新一期的专题中，我们将总结出针对宽带应用的30条实用技巧。ATA接口硬盘磁盘介质的存储密度正在大步升级（如今市场上不乏每平方英寸45-50Gbits的产品，而在一年前这个数值仅为33-35Gbits左右），新技术的应用更是为我们熟悉的硬盘增添了绚丽的光彩，事实上，大容量硬盘…     

轻松迈向互连网──方正家用电脑

方正推出的基于 ISDN宽带技术的方正卓越 3000家用电脑和基于 ADSL宽带技术的方正卓越 6000家用电脑,为全面整合家用电脑的信息处理能力和 Internet通信能力做出了新的尝试。新一代方正卓越系列家用电脑具有强大的运算能力、完善的 Internet应用功能和高速数据交换技术。基于 ISDN的方正电脑卓越 3000－ ISDN系列家用电脑可以帮助用户在普通的电话线上进行全数字通信业务,并且不需要再另外购买安装复杂的 ISDN专用设备,用户就能够实现高速上网、可视电话、网上教育、远程医疗等多种业务。通过一条电话线,用户可以同时打电话…     

一线多能 万事皆通的ISDN

一、什么是 ISDN 　　1SDN中文名称是综合业务数字网（ ISDN— Intergrated Service Digital Network）,又称“一线通 "。是目前广泛使用的因特网接入方式。 　　综合业务数字网有窄带（ N— ISDN）和宽带（ B— ISDN）之分。其提供的通信能力是这样的：窄带是 2B＋ D,即 128KB/S,宽带是 30B＋ D,即 2MB/S。这里介绍的属于窄带综合业务数字网（ N— ISDN）,而且,一般不特别说明的时候, ISDN均指 N— ISDN。 　　ISDN采用数字传输和数字交换技术。将电话、传真、数据、图象等多种业务综合在一个统一的数字网络…     

ATM节点交换机51Mb/s线路终端接口电路的设计

在宽带综合业务数字网络（B－ISDN）中，ATM作为B－ISDN的核心技术，在通讯系统中占据了重要地位。本文主要介绍了ATM节点交换机51Mb/s线路终端接口电路的设计。     

电子信息科技的发展态势（3）

三、现代通俗技术现代通信的目标是“全球一网”！其基础是数字技术、计算机技术、微电子与光电子技术。总的趋势是数字化、宽带化、综合化、智能化与个人化，最终是构成一个全球一体的宽带、智能、个人化的综合业务数据网BIP－ISDN！当今通信界的三股热流是：光纤通信、卫星通     

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.