ISTAR — a tool for creative design of knowledge bases

This paper gives a comprehensive explanation of the Istar knowledge representation software tool. Not only does it describe the features and facilities found in Istar, but it discusses why they are as they are.
Istar is one of a new generation of knowledge representation tools, aimed at ill-structured domains of knowledge. While it can be used in traditional KBS projects, in which pieces of knowledge from a domain expert are assembled to form a working knowledge base, it is designed for situations in which there is a large element of creative design: knowledge refinement and generation resulting from the knowledge representation process.
The knowledge representation 'language' is purely graphical; the knowledge engineer 'draws' knowledge on an easel as a box and arrows diagram. Behind this diagram is the knowledge base itself, in the form of integrated inference nets, Bayesian nets and semantic nets. This paper discusses the reasons for these design choices and, briefly, some of the issues faced in development of Istar.     

Design and implementation of a video browsing system for the Internet

Recent advances in multimedia processing technologies, internet‐working technologies, and the World Wide Web phenomenon have resulted in a vast creation and use of digital videos. Due to this reason, an efficient technique to locate and retrieve a desired video from a remote video archive is needed. A trial‐and‐error approach popularly used in current Web search engines is not applicable for searching for a desired video segment since the technique incurs intolerable delays. In this paper, we present the design and implementation of a video browsing system that lets the user view a summary of a selected video and search within the video while being downloaded so that the user can determine the relevance of the video as early as possible. The system is inexpensive and scalable, making it suitable for large‐scale distributed systems such as the Internet. The browsing system consists of two major software components: a video server, and a video browser and player called VideoCenter implemented using Microsoft DirectShow multimedia development kit. The implementation of VideoCenter enables us to assess the ease of use of DirectShow as well as its drawbacks in developing multimedia applications. Copyright © 2001 John Wiley & Sons, Ltd.     

Visual preview for link traversal on the World Wide Web

This paper demonstrates a technique for augmenting current World Wide Web browser implementations with features found in classical hypertext applications but unknown to the World Wide Web community until now. An example implementation is shown using Netscape Navigator 4.x using JavaScript, dynamic HTML and Java. The implementation follows an architecture based on a proxy server which acts as a gateway between the Internet and the browsing client. Based on the detailed example, support for further features is discussed.     

A testbed for performance evaluation of load‐balancing strategies for Web server systems

To improve response time of a Web site, one replicates the site on multiple servers. The effectiveness of a replicated server system will depend on how the incoming requests are distributed among replicas. A large number of load‐balancing strategies for Web server systems have been proposed. In this paper we describe a testbed that can be used to evaluate the performance of different load‐balancing strategies. The testbed uses a general architecture which allows different load‐balancing approaches to be supported easily. It emulates a typical World Wide Web scenario and allows variable load generation and performance measurement. We have performed some preliminary experiments to measure the performance of a few policies for load balancing using this testbed. Copyright © 2003 John Wiley & Sons, Ltd.     

A Web-Based Knowledge Network for Supporting Emerging Internet Applications

Although the Internet and the World Wide Web technologies have gained a tremendous amount of popularity among people and organizations, the network that these technologies created is not much more than a multimedia data network. It provides tools and services for people to browse and search for data but does not provide the facilities for automatically delivering the relevant information for supporting decision–making to the right people or applications at the right time. Nor does it provide the means for users to enter and share their knowledge that would be useful for making the right decisions. In this work, we introduce the concept of a Web–based knowledge network, which allows users and organizations to publish, not only their multimedia data, but also their knowledge in terms of events, parameterized event filters, customizable rules and triggers that are associated with their data and application systems. Operations on the data and application systems may post events over the Internet to trigger the processing of rules defined by both information providers and consumers. The knowledge network is constructed by a number of replicable software components, which can be installed at various network sites. They, together with the existing Web servers, form a network of knowledge Web servers.     

基于ASP的Web动态页面实现

万维网Web是Internet上广泛使用的一种服务,它为因特网用户提供了丰富多样的信息资源。随着Web的发展,初期的静态页面已不能满足用户的需求,活动和动态页面成为Web中不可缺少的内容。本文探讨了在Web应用开发中采用服务器端比较流行的ASP来实现动态页面的方法。     

Information mediation in cyberspace: Scalable methods for declarative information networks

An end-to-end discussion, from logical architecture to implementation, of issues and design decisions in declarative information networks is presented. A declarative information network is defined to be a dynamic and decentralized structure where value-added services are declared and applied as mediators in a scalable and controlled manner. A primary result is the need to adopt dynamically linked ontologies as the semantic basis for knowledge sharing in scalable networks. It is shown that data mining techniques provide a promising basis upon which to explore and develop this result. Our prototype system, entitled Mystique, is described in terms of KQML, distributed object management, and distributed agent execution. An example shows how we map our architecture into the World Wide Web (WWW) and transform the appearance of the WWW into an intelligently integrated and multi-subject distributed information network.     

基于移动Agent的Web缓冲与远程控制技术的研究

随着WWW的流行,Internet的需求变得非常大,扩展Internet的关键策略是对客户端进行缓冲以降低访问延迟和减少网络及服务器的负载,文章示意了用IBMAglet实现Web缓冲的方法,并讨论了基于移动Agent远程控制技术的内部结构及使用Socket在C 中实现来描述Aglet通信机制的实现过程。     

Knowledge Issues Raised in Modelling Trust in a Public Key Infrastructure

The paper describes a knowledge-based system for modelling trust in the certification authority (CA) of a public key infrastructure. It was built using a graphical knowledge-based system toolkit, Istar, that allows the knowledge builder to easily model the important relationships between concepts of the domain. The knowledge base was initially built using published work and was subsequently extended by knowledge obtained from leading public key infrastructure experts. The first prototype system computes the trust in a CA by asking the user a series of questions about the CA's Certification Practice Statement. Examples of its use with two well-known public CAs is discussed.
An important issue raised and discussed in this paper is how to map symbols in the knowledge base to the knowledge level of human trust and beliefs, for such an ill-defined area of knowledge as trust, and four main mappings have been identified. Another issue that emerged relates to the use of questionnaires during knowledge acquisition. The expert system is currently available online via the Istar knowledge server, and future work is discussed.     

基于EWS的分布式监控系统的研究与开发

基于对嵌入式系统和Web技术的研究，将Web服务器引入到分布式监控系统中，把工业现场的实时监控通过TCP/IP协议和Web sever接入Internet，实现了控制网络和数据网络一体化。该文给出了监控系统的网络结构，并对嵌入式Web服务器的关键技术的实现进行了分析。     

Ex-W-Pert system: A Web-based distributed expert system for groupware design

The World Wide Web (Web) allows people at remotely located sites to communicate and share their ideas using a common communication protocol. A common use of the Web system is running a client application, using a browsing tool, by pointing to a local or proxy server to browse data written in the hypertext format that contains anchors that address other URLs. In this paper a new application of the Web system for sharing knowledge-based systems and groupware development activities is introduced. An architecture for a Web-based Distributed Expert System (Ex-W-Pert System) is proposed and an implementation of the proposed architecture in groupware design is demonstrated. The resources and knowledge bases are distributed and can be accessed through the internet.     

A comparison of multimedia application development platforms towards the object web

In this paper, a complete scenario for the provision of interactive multimedia services over the Internet is considered, exploiting emerging software methodologies that implement different aspects of what is called the object web.Initially, web-application design considerations over the years are presented, in parallel to the evolution of the World Wide Web. Then, the study focuses on a distributed multimedia application aiming to deliver, over the Internet, information on children's TV programs and co-productions. Two different object oriented implementation models are described, the HTTP/Microsoft's active server pages (ASP) approach and the Java/common object request broker architecture (CORBA) approach. Finally, experimental results comparing the two implementation models are presented and the advantages gained from the latter are highlighted.     

From Interactive Television to Internet Applications

Early in 1993 Viacom and a major telephony carrier formed a joint venture to trial interactive television (ITV) in Castro Valley, California. During the fall of 1994, it was decided not to complete this trial. Both companies decided, given what had already been learned planning for the ITV trial and the emerging strength of the Internet and the World Wide Web, that it would be more effective to focus on CD-ROMs, proprietary on-line services, and the Internet, including the World Wide Web, where many of the interactive applications that had been planned for ITV could be actually implemented and made available to large numbers of users. This paper discusses the interactive systems, and economic environments along with major issues, intellectual property rights, and Viacom's current direction.     

Doing business on the Net

Originally created for the military and developed by researchers, the Internet has been discovered by the world of commerce. Many companies are establishing World Wide Web sites to promote their products and services. However, they may be so busy establishing business procedures and strategies that they may not consider some important legal issues. Those issues reflect the Web's high-tech nature and worldwide reach. The paper discusses issues such as trademark clearance, Web page design, product sales and customer privacy     

基于web挖掘的用户服务研究

数据丰富而知识贫乏导致了知识发现和数据挖掘领域的出现。基于Web的数据挖掘，是从Web海量的数据中自动、智能地抽取隐藏于这些数据中的知识，分析了Web挖掘技术的概念、特点、技术等。根据Web数据挖掘最流行的分类，可以分为Web内容挖掘、Web结构挖掘和Web使用记录挖掘。其中Web使用挖掘就是运用数据挖掘的思想来对服务器日志进行分析处理。该文根据Web数据挖掘的最近研究状况，主要论述了一个更新的频繁路径集的挖掘浏览模式在Web用户个性化服务中的应用，同时，还对发现的知识讨论了其在在线服务中的应用并给出了相应算法。     

Knowledge acquisition, modelling and inference through the World Wide Web

The development of knowledge-based systems involves the management of a diversity of knowledge sources, computing resources and system users, often distributed geographically. The knowledge acquisition, modelling and representation communities have developed a wide range of tools relevant to the development and management of large-scale knowledge-based systems, but the majority of these tools run on individual workstations and use specialist data formats making system integration and knowledge interchange very problematic. However, widespread access to the Internet has led to a new era of distributed client–server computing. In particular, the introduction of support forformson World Wide Web in late 1993 has provided an easily programmable, cross-platform graphic-user interface that has become widely used in innovative interactive systems. This article reports on the development of open architecture knowledge management tools operating through the web to support knowledge acquisition, representation and inference through semantic networks and repertory grids.     

信息技术考试系统中模拟Internet的实现技术

在中小学信息技术考试系统中，Internet操作是很重要的内容。该文介绍了用VB开发嵌入在客户端的Web服务器和E-mail服务器的设计思想和实现过程，并且在单机上实现模拟Internet的技术。     

Delivery of video mail on the World Wide Web

This study was initiated to examine the feasibility of providing multimedia mail, in particular video mail, on the existing World Wide Web platform. In this instance, the Web browser will act as the user agent of the mailing system. With this, users will be able to compose, send and read video mail directly on the Web. This paper examines a number of possible system architectures that can be employed for the development of video mail. Based on the following key issues: portability of system, flexibility of system, Internet standard support, security and authentication, and message compression and storage, a final architecture was selected to build video mail. The approach taken is that the system will be interfaced to the Web using a standard HyperText Transfer Protocol (HTTP) server and a standard Web browser. This is achieved through the use of Common Gateway Interface (CGI) programs and forms which reside in a standard HTTP server to provide the functionality of video mail, and a separate mail server for the storage and management of messages. This will cause the HTTP server to behave as if it is an electronic mail (E-mail) system. Video mail has been successfully implemented at the School of Applied Science, Nanyang Technological University, Singapore. The development work has been carried out on a Sun SPARC5 workstation and the Typhoon relational database system was used to construct the mail server. All software codes were written in C or C++. A video capturing application used in conjunction with a SunVideo card has been developed for video and audio recording. The paper also addresses implementation issues pertaining to the use of CGI programs, mail server development, and video and audio management.     

支持异地协同产品设计的知识服务模型

提出基于XML元语言，以统一的信息化格式描述设计知识，使用Java技术构建了支持多专家协同设计的基本框架，将各类设计服务封装为Web服务的形式，实现了一种Web使能的知识服务模型(Web-KSS)，并应用该模型实现了支持成套电器产品设计的知识服务系统。     

可定题的中文网络信息自动发现系统

随着Internet应用的逐渐普及,WWW己经发展成为个巨大的分布式信息空间,为用户提供了一个极具价值的信息源。快速、准确地发现定题领域中的信息,是广大网站管理员和用户所需要的;文章介绍了一种可定题的网络信息自动发现系统;并说明系统的设计思想,关键技术和实现。