面向对象的专家知识模型

文中用面向对象方法来分析、设计基于规则的专家系统,提出一种新的采用分层递阶结构的专家知识模型,并从结构和功能角度进行详细阐述。     

Utopia: A load sharing facility for large,heterogeneous distributed computer systems

Load sharing in large, heterogeneous distributed systems allows users to access vast amounts of computing resources scattered around the system and may provide substantial performance improvements to applications. We discuss the design and implementation issues in Utopia, a load sharing facility specifically built for large and heterogeneous systems. The system has no restriction on the types of tasks that can be remotely executed, involves few application changes and no operating system change, supports a high degree of transparency for remote task execution, and incurs low overhead. The algorithms for managing resource load information and task placement take advantage of the clustering nature of large-scale distributed systems; centralized algorithms are used within host clusters, and directed graph algorithms are used among the clusters to make Utopia scalable to thousands of hosts. Task placements in Utopia exploit the heterogeneous hosts and consider varying resource demands of the tasks. A range of mechanisms for remote execution is available in Utopia that provides varying degrees of transparency and efficiency. A number of applications have been developed for Utopia, ranging from a load sharing command interpreter, to parallel and distributed applications, to a distributed batch facility. For example, an enhanced Unix command interpreter allows arbitrary commands and user jobs to be executed remotely, and a parallel make facility achieves speed-ups of 15 or more by processing a collection of tasks in parallel on a number of hosts.     

Some knowledge-acquisition methods for prospector-like systems

The paper deals with the knowledge-acquisition methods designed and tested under the FEL-EXPERT Project, which is aimed at the development of rule-based diagnostic shells. Three different approaches have been used for knowledge acquisition: pattern-recognition, decision-tree, and intensional, pure probabilistic approaches. The designed methods may be applied to a wide subclass of rule-based diagnostic systems that exploit the pseudo-Bayesian model for uncertainty handling. The experimental results are discussed.     

KMS中用户知识共享行为模型的构建

用户知识共享行为是影响知识管理系统KMS（knowledge management systems,KMS）能否取得预期运行效果的关键因素。现有的一些KMS还不具有根据用户日常的知识活动自动评估用户知识共享行为的功能,限制了KMS在知识共享文化形成中的作用。在此从行为和动作的表示入手,基于BNF的行为表示体系、知识共享行为ontology和行为树映射方法,提出了一个动态、实时、自适应、交互式用户知识共享行为模型,该模型包括基于BNF的行为和动作的表示、知识共享行为ontology、用户知识共享行为树及其动态创建过程等内容,能够实现从数量上对用户知识共享的参与度做出评价,可以作为开发实现该功能的Agent程序的一般框架。     

基于知识交易的知识共享仿真系统研究

根据知识向量和不同的主体策略,构建了知识共享网络的基于知识交易的知识共享仿真过程模型.通过仿真分析,发现主体采用利他交易策略的知识共享系统的整体效率要高于采用互惠交易策略的系统整体效率;在知识共享网络规模较小的情形下,系统不存在明显的一个知识水平高峰的特征.     

A different paradigm for expert systems: an introduction to logic programming and related knowledge representation issues

Abstract: Current expert system technology is 30 years old. Expert system shells find their origins in the work of early expert systems, most notably MYCIN which was developed at Stanford in the mid-1970s. Even Prolog programmers are settling for less robust reasoning power. The logic programming community (from which both expert systems and Prolog arose) has made notable advances since those times. These advances are lacking from current expert system technology. The advances include a well-developed theory of multiple forms of negation, an understanding of open domains and the closed world assumption, default reasoning with exceptions, reasoning with respect to time (i.e. a solution to the frame problem, and introspection with regard to previous beliefs), reasoning about actions, introspection, and maintaining multiple views of the world simultaneously.
The contribution of this paper is to discuss these developments in a singular, integrated, practical, digestible manner. Some of these ideas exist in a variety of papers spread across decades. They also exist in the minds of a very small community of researchers. Some of these ideas are unpublished. The presentation in this paper is from a different point of view, and intended to be more comprehensive and pedagogical. The presentation is also intended to be accessible to a much wider audience. Both the synthesis and the simplicity of this presentation are absent from the literature.     

Representing and using legal knowledge in integrated decision support systems: DataLex WorkStations

There is more to legal knowledge representation than knowledge-bases. It is valuable to look at legal knowledge representation and its implementation across the entire domain of computerisation of law, rather than focussing on sub-domains such as legal expert systems. The DataLex WorkStation software and applications developed using it are used to provide examples. Effective integration of inferencing, hypertext and text retrieval can overcome some of the limitations of these current paradigms of legal computerisation which are apparent when they are used on a stand-alone basis. Effective integration of inferencing systems is facilitated by use of a (quasi) natural language knowledge representation, and the benefits of isomorphism are enhanced. These advantages of integration apply to all forms of inferencing, including document generation and casebased inferencing. Some principles for development of integrated legal decision support systems are proposed.     

An efficient weighted bi-objective scheduling algorithm for heterogeneous systems

This paper proposes the Makespan and Reliability Cost Driven (MRCD) heuristic, a static scheduling strategy for heterogeneous distributed systems that not only minimizes the makespan, but also maximizes the reliability of the application. The MRCD scheduling decisions are guided by a weighted function that considers both objectives simultaneously, instead of prioritizing one of them. This work also introduces a classification of the solutions produced by weighted bi-objective schedulers to aid users to tune the weighting function such that an appropriate solution can be selected in accordance with their needs. In comparison with the related work, MRCD produced schedules with makespans that were significantly better then those produced by the other strategies at expense of an insignificant deterioration in reliability.     

An exploration of expertise of knowledge workers: towards a definition of the universe of discourse for knowledge acquisition

Abstract. Knowledge systems development and use have been significantly encumbered by the difficulties of eliciting and formalizing the expertise upon which knowledge workers rely. This paper approaches the problem from an examination of the knowledge competencies of knowledge workers in order to define a universe of discourse for knowledge elicitation. It outlines two categories and several types of knowledge that could serve as the foundations for the development of a theory of expertise.     

数字化图书馆知识共享策略研究

数字化图书馆知识共享,有利于提高图书馆的竞争力、促进隐性知识显性化、降低图书的投资成本.促进数字化图书馆知识共享需要多措并举：营造图书馆知识共享的文化氛围,建立图书馆知识共享联盟,搭建有利于知识共享的运作平台.     

Distributed recommender for peer-to-peer knowledge sharing

A novel model of distributed knowledge recommender system is proposed to facilitate knowledge sharing among collaborative team members. Different from traditional recommender systems in the client-server architecture, our model is oriented to the peer-to-peer (P2P) environment without the centralized control. Among the P2P network of collaborative team members, each peer is deployed with one distributed knowledge recommender, which can supply proper knowledge resources to peers who may need them. This paper investigates the key techniques for implementing the distributed knowledge recommender model. Moreover, a series of simulation-based experiments are conducted by using the data from a real-world collaborative team in an enterprise. The experimental results validate the efficiency of the proposed model. This research paves the way for developing platforms that can share and manage large-scale distributed knowledge resources. This study also provides a new framework for simulating and studying individual or organizational behaviors of knowledge sharing in a collaborative team.     

Expert knowledge acquisition and the unwilling expert: a knowledge engineering perspective

Expert systems are an evolving technology with the potential to make human expertise widely and cheaply available. The literature describing the development of expert systems generally assumes that experts willingly give up their knowledge. This is unrealistic and may be a reason why most expert system projects fail. This paper explores the problem of unwilling experts from the perspective of a knowledge engineer building an expert system. The link between knowledge and organizational power is established and human motivation theories are discussed. Finally, a new motivational approach is introduced to help the knowledge engineer deal with unwilling experts.     

Extension of the temporal synchrony approach to dynamic variable bindingin a connectionist inference system

The relationship between symbolism and connectionism has been one of the major issues in recent artificial intelligence research. An increasing number of researchers from each side have tried to adopt the desirable characteristics of the approach. A major open question in this field is the extent to which a connectionist architecture can accommodate basic concepts of symbolic inference, such as a dynamic variable binding mechanism and a rule and fact encoding mechanism involving nary predicates. One of the current leaders in this area is the connectionist rule-based system proposed by Shastri and Ajjanagadde. The paper demonstrates that the mechanism for variable binding which they advocate is fundamentally limited, and it shows how a reinterpretation of the primitive components and corresponding modifications of their system can extend the range of inference which can be supported. Our extension hinges on the basic structural modification of the network components and further modifications of the rule and fact encoding mechanism. These modifications allow the extended model to have more expressive power in dealing with symbolic knowledge as in the unification of terms across many groups of unifying arguments.     

Model for knowledge and legal expert systems

This paper presents a four layer model for working with legal knowledge in expert systems. It distinguishes five sources of knowledge. Four contain basic legal knowledge found in published and unpublished sources. The fifth consists of legal metaknowledge. In the model the four basic legal knowledge sources are placed at the lowest level. The metaknowledge is placed at levels above the other four knowledge sources. The assumption is that the knowledge is represented only once. The use of metaknowledge at various levels should make it possible to use the appropriate knowledge for the problem presented to the system. The knowledge has to be represented as closely to the original format as possible for this purpose. Suitable representation formalisms for the various types of knowledge in the five knowledge sources are discussed. It is not possible to indicate a best representation formalism for each knowledge source.     

An integrated knowledge representation scheme and query processing mechanism for fault diagnosis in heterogeneous manufacturing environments

An integrated fault diagnosis system was developed for manufacturing complex products, e.g., automobile, that undergo a variety of production processes. The proposed global knowledge representation scheme is designed to consistently express such heterogeneous diagnostic knowledge in terms of the causal relations among relevant attributes across different processes. This scheme is unifying in that it reflects the fact that an effect for one causal relation may in turn be a cause for another along a chain of subsequent processes. In order to unify independent pieces of causal relation, specific attributes of machine-processed products in addition to the usual diagnostic signals such as noise and voltage of the machines. The accompanying probabilistic diagnosis mechanism can then produce an enhanced diagnostic accuracy over other existing schemes as it can simultaneously consider multiple causes of a fault along with their interdependency. The proposed diagnosis mechanism was implemented in a distributed computer environment to identify the functions and procedures required for its actual application.     

Transactive memory systems and Web 2.0 in knowledge sharing: A conceptual model based on activity theory and critical realism

The aim of this paper is to advance understanding of interactive knowledge sharing (KS) processes through exploring the role of transactive memory systems (TMSs) and Web 2.0. In the context of the information systems literature, there is little focus on their particular role in KS. To address this gap, this paper develops a conceptual model based on activity theory and critical realism outlining the role of TMS and Web 2.0 as mediating tools. This paper further reveals that their use as tools depends on deeper underlying structures/factors embedded within the community, namely, informal networks and trust among people. The new conceptual model and theoretical propositions are then illustrated by a qualitative study undertaken in Bulgarian organisations. This illustrative case provides support for the model, where TMS and Web 2.0 are found to facilitate KS. It further demonstrates that informal networks and trust among people support the use and the positive effects of these tools. The contribution of this paper is in the new analytical approach and conceptual model developed, which advances our understanding of interactive KS by explaining the linkages between the various factors involved.     

A knowledge system for integrated product design

This paper discusses the architecture and implementation issues for a knowledge system to assist in product design. The goals of the concurrent Design Advisor (CODA) are to enhance the quality of designs by 25 percent and the efficiency by a factor of 10. The improvement springs from the integration of diverse knowledge bases, ranging from customer needs to product evaluation, and from process configuration to production control. One source of efficiency is the automation of many routine tasks, thereby increasing user productivity. Another source is the increase in the quality of initial designs, which obviates the need for numerous iterations in the design process due to poor manufacturability. CODA is based on the general architecture of the Creativity Support System, an expert system for assisting users in specific domains requiring creative solutions. The bilevel structure of the system consists of a domain-independent module containing general tools and techniques for creative problem-solving, and a domain-dependent module incorporating knowledge specific to particular fields of application. The utility of this approach is illustrated in the realm of concurrent product design by demonstrating a CODA within the general architecture of the system.