KNOWLEDGE-BASED SYSTEMS FOR USERS

Although knowledge-based systems are already assisting help-desk staff in the IS department to solve systems development and similar problems, they have yet to become a fully functional part of user support help desks. The two adviser applications described in this article illustrate how easily these knowledge-based systems can be developed and, even more important, how more productive they can make the help-desk staff and the users themselves.     

基于知识的CSCW人机接口模型

人机接口是ＣＳＣＷ系统的重要组成部分，也是它的难点之一。本文针对ＣＳＣＷ系统中用主动作的协同特性，提出了一种协同人机接口结构模型ＫＣＨＣＩ，通过对用户动作的多层抽象和对动作结果的多层例化，实现多用户之间的多层次协同及感知，同时，以知识作为规范描述语言，不仅增强了接口的灵活性，提高了接口的协同效率，也方便了接口的开发。     

MULTIPLY SECTIONED BAYESIAN NETWORKS AND JUNCTION FORESTS FOR LARGE KNOWLEDGE-BASED SYSTEMS

Bayesian networks provide a natural, concise knowledge representation method for building knowledge-based systems under uncertainty. We consider domains representable by general but sparse networks and characterized by incremental evidence where the probabilistic knowledge can be captured once and used for multiple cases. Current Bayesian net representations do not consider structure in the domain and lump all variables into a homogeneous network. In practice, one often directs attention to only part of the network within a period of time; i.e., there is "localization" of queries and evidence. In such case, propagating evidence through a homogeneous network is inefficient since the entire network has to be updated each time. This paper derives reasonable constraints, which can often be easily satisfied, that enable a natural {localization preserving) partition of a domain and its representation by separate Bayesian subnets. The subnets are transformed into a set of permanent junction trees such that evidential reasoning takes place at only one of them at a time; and marginal probabilities obtained are identical to those that would be obtained from the homogeneous network. We show how to swap in a new junction tree, and absorb previously acquired evidence. Although the overall system can be large, computational requirements are governed by the size of one junction tree.     

eXist数据库结构连接算法的改进和实现

为了进一步提高eXist数据库的查询效率,针对数据库现有的数据存储特点和查询策略,提出一种快速定位的结构连接算法FL-Stack。算法采用栈缓存已遍历过的但仍可能与尚未遍历的后代结点匹配的祖先结点,并对能预先判断不可能满足结构连接匹配的祖先或后代结点,提出相应方法实现快速定位,以批量跳过这类结点。与现有算法必须逐个扫描祖先后代结点序列相比,这种快速定位的结构连接算法避免了逐个扫描带来的多次重复无意义的比较,可大大提高结构连接效率。     

AMPERES: A REAL-TIME FAULT MONITORING AND DIAGNOSIS KNOWLEDGE-BASED SYSTEM FOR SPACE POWER SYSTEMS

A real-time fault monitoring and diagnosis knowledge-based system (KBS) has been developed for space power systems to save costly operational manpower and to achieve reliable space power system operation. The developed KBS, called AMPERES (autonomously managed power-system extendible real-time expert system), was developed using the autonomously managed power system (AMPS) test facility currently installed at NASA Marshall Space Flight Center (MSFC). The approaches taken for AMPERES are generic and should be applicable for other space power systems. A sensor value validation method based on causal relations (CRs) and their interrelations within the sensor redundancy graphs (SRG) has been developed and applied in AMPERES to increase the confidence in the validity of the sensor values and consequently in the results of the fault diagnosis. The validation results also yield essential information for fault diagnosis identifying the existence of a potential fault and the location or the extent of the fault. A disturbance interrelation analysis graph (DIAG) scheme has been developed to characterize the fault diagnosis problems clearly and to perform the fault monitoring and diagnosis tasks effectively by explicitly showing the diagnosis reasoning paths. The DIAG approach also enables the fault diagnosis KBS to describe a fault in several different abstraction levels and in different component granularities.     

交互软件系统的一种构造方法

本文根据作者近年来研究交互软件的工作实践,阐述了交互软件系统的一种构造方法.文章介绍了构造活动的工作过程模型,并以一个试验系统加以具体解释,文章对于用户接口管理和具有4GL(Fourth Generation Lan-guage)特征的交互语言,以及和交互系统相关的一些新颖的概念,也作了简要的介绍①。     

一种模糊专家数据库数据模型

本文提出了一种能处理模糊知识的专家数据库数据模型。详细介绍了其模糊知识表示，模糊关系代数及不精确推理的实现策略。     

信号与系统分析软件研究

信号与系统分析中很多方法较为抽象,计算繁琐,借助Visual Basic（VB）和MATLAB程序设计语言的强大功能,设计并开发出了信号与系统分析软件平台。软件平台包括了连续信号与系统的时域分析方法和变换域分析方法,以及离散时间信号的时域和Z域分析方法等信号与系统中的主要内容。此外,还包括了滤波器设计等内容。对软件功能的设计、以及实现中的关键技术等进行了详述。软件的研制,使得信号与系统分析中复杂抽象的理论变得简单直观,软件界面友好,功能完善,实际应用取得了良好效果。     

KNOWLEDGE-BASED ACADEMIC ADVISING SYSTEMS: SURVEY,EVALUATION, AND RECOMMENDATIONS

The purpose of academic advising is to help students to develop educational plans. In universities faculty perform as academic advisors to students. Recently a number of rule-based systems were developed to help faculty and students with the advising task. In this paper we consider briefly the purpose and goals of academic advising. This consideration results in proposal of a number of major goals for constructing knowledge-based advisors. We then review a number of representative recent rule-based advising systems and evaluate them with respect to satisfaction of the proposed goals. The paper concludes with a recommendation for a new approach.     

用户级通信在软件分布式共享存储系统中的应用与分析

通过信能不高是影响软件分布式共享存储系统性能的主要因素之一,用户级通信技术能够充分发挥高速网络的硬件性能,减少数据拷贝次数,降低软件件开发销,明显改善了带宽和延迟,为软件分布式共享存储系统性能的提高开避了新的途径,设计并实现了一个面向软件分布式存储系统的用户级通信库,它不仅改善了系统的通禽性能,同时也使得系统的并行计算性能得到改善,从而十分显著地提高了软件分布式共享存储系统的整体性能。     

嵌入式系统的软件保护方案

随着嵌入式产品的日渐普及,嵌入式产品的知识产权保护问题渐渐凸现.对于大多数商用嵌入式产品来说,有必要引入一些软件保护机制来完成知识产权保护的目的.针对这种情况,介绍了嵌入式环境下的一些软件保护方案,包括不需硬件支持的纯软件实现方案,以及与硬件结合的、强度更高的实现方案.并描述了这些方案各自的优缺点,以及典型应用场景.     

实时数据库系统的内存数据库组织与故障恢复

本文给出一种在内存数据库中能有效节约内存空间的数据组织结构--内存数据库图(MMDBG),然后给出MMDBG的物理组织形式.并重点讨论了基于MMDBG的事务恢复和系统恢复算法,在最大程度上提高系统的响应时间和支持实时事务.     

主动数据库的时序事件代数

通过引入一元时序算子,表达事件之间任意杂的相对次序关系,在此基础上重新定义了描述复合件的时序事件代数,并证明了该事件代数良好的数学性质,不仅增强了事件描述语言的描述能力,也为处理规划执行的合流性提供了新的方法。     

EXPERIMENTAL SYSTEMS RESEARCH: TOWARD A LABORATORY FOR THE GENERAL THEORY

For those, like me, who are not mathematicians, the computer can be a powerful friend to the imagination. Like mathematics, [the computer] doesn't only stretch the imagination. It also disciplines and controls it.     

A NEW METHOD FOR FUZZY QUERY PROCESSING IN RELATIONAL DATABASE SYSTEMS

In this paper, we present a new method for fuzzy query processing in relational database systems based on automatic clustering techniques and weighting concepts. The proposed method allows the query conditions and the weights of query items of users' fuzzy SQL queries to be described by linguistic terms represented by fuzzy numbers. Because the proposed fuzzy query processing method allows the users to construct their fuzzy queries more conveniently, the existing relational database systems will be more intelligent and more flexible to the users.     

概念代数—新一代数据库系统的理论

念代数ＣＡ是Ｎｉｌｓｓｏｎ教授以格（ｌａｔｔｉｃｅ）理论为数学背景提出的一个新的代数系统。在ＣＡ中，关系范型、ＯＯ范型、逻辑程序设计和框架知识表示获得了统一的表示－概念项，项进一步组成句子。一个完整的知识库就由这样折的项和句子组成。推理操作是一组被称为重写规则的代数公理。目前的ＣＡ还只是个代数系统雏形，有很多方面有待扩充。本文对概念代数进行综述，并给出初步的扩充。     

多系统通用界面软件的设计与实现

本文从如何提高软件可移植性问题出发，论述了开发多系统通用界面软件的应用需求，软件设计总体目标及其设计思想；程序的结构设计、软件设计和实现中的主要技术关键和难点，以及操作系统原命令语言应用机制和系统库作支撑环境的设计特点。文章最后阐述了人机界面标准化问题的重要性。     

面向非软件专业人员的一种软件系统集成方案

数值仿真类软件是科学研究和工程设计中的一类常用软件。开发该类软件需解决非软件专业人员在软件开发能力上的局限性,以保证软件开发质量与进度。以火箭发动机数值仿真软件开发为背景,提出了适用于此类软件开发的一种软件系统集成方案。该方案在传统的软件分层模型的基础上,使用代码自动生成技术,实现了模块封装接口的自动代码生成和参数修改用户界面自动代码生成。该方案所使用的代码自动生成技术还可用于用户自定义仿真模块的开发,保证了集成系统开放性。由于使用了代码自动生成技术,非软件专业人员的开发工作集中于其所熟悉的专业领域,加快了开发进度,在一定程度上减少了劣质代码的产生。研究表明,该方案可以有效解决非软件专业人员在软件开发中作用难以发挥的问题。研究工作还可为行业软件等其它类似软件的开发提供参考。     

A KNOWLEDGE-BASED SYSTEM FOR COURSE SCHEDULING

Abstract

A knowledge-based scheduling system has been developed for the domain of university class scheduling. The problem addressed is how to schedule courses during the various time periods throughout the day. The class schedule must satisfy a variety of appropriate constraints. The system, written in Prolog, resolves conflicting assignments through backtracking. The inefficiency of Prolog's backtracking feature, with respect to this application, is partly circumvented by the use of a dynamic circular array. The system is now being used to help schedule industrial engineering classes at the Pennsylvania State University.     

多媒体智能数据库系统体系结构的选择

多媒体智能数据库系统是一个对象数据库管理系统。体系结构的选择对它的性能和功能有非常重要的影响。在体系结构的选择过程中我们始终遵循这样的一条准则：性能更为重要，因为功能可以在ＯＤＢＭＳ的上层的应用程序中增加，而性能上的缺陷是不可能在应用程序层次上得以弥补的。本文讨论和比较了ＯＤＢＭＳ的若干体系结构及其实现方案，最后给出了一个有较高性能ＭＩＤＳ体系结构方案。