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1.
A Logical Framework for Knowledge Base Maintenance   总被引:3,自引:1,他引:2       下载免费PDF全文
The maintenance sequences of a knowledge base and their limits are introduced.Some concepts used in knowledge base maintenance,such as new laws,user‘s rejections,and reconstructions of a knowledge base are defined;the related theorems are proved.A procedure is defined using transition systems;it generates maintenance sequences for a given user‘s model and a knowledge base.It is proved that all sequences produced by the procedure are convergent,and their limit is the set of true sentences of the model.Some computational aspects of reconstructions are studied.An R-calculus is given to deduce a reconstruction when a knowledge base meets a user‘s rejection.The work is compared with AGM‘s theory of belief revision.  相似文献   

2.
A new type of intelligent CAI system for chemistry is developed in this paper based on automated reasoning with chemistry knowledge.The system has shown its ability to solve chemistry problems,to assist students and teachers in studies and instruction with the automated reasoning functions.Its open mode of the knowledge base and its unique style of the interface between the system and human provide more opportunities for the users to acquire living knowledge through active participation.The automated reasoning based on basic chemistry knowledge also opened a new approach to the information storage and management of the ICAI system for sciences.  相似文献   

3.
In this paper,we present a programmable method of revising a finite clause set.We first present a procedure whose formal parameters are a consistent clause set Γand a clause A and whose output is a set of minimal subsets of Γwhich are inconsistent with A.The maximal consistent subsets can be generated from all minimal inconsistent subsets.We develop a prototype system based on the above procedure,and discuss the implementation of knowledge base maintenance.At last,we compare the approach presented in this paper with other related approaches,The main characteristic of the approach is that it can be implemented by a computer program.  相似文献   

4.
Sme concepts used in knowledge base maintenace,such as sequence,new law,user‘s rejection and reconstructions of a knowledge base,are first introduced,and then a framework for extended logic programming(ELP)is given,where an extended logic program is equivalent to a knowledge base.A transition system called R-calculus for ELP is provided.For a given knowledge base and a user‘s rejection,the R-calculus for ELP will deduce best revisions of the base.The soundness and the completeness of the R-calculus for ELP are proved,and the R-calculus for ELP is implemented in Prolog.In addition,the research is compared with other relevant work.  相似文献   

5.
This contribution discusses the concept of Reliability-Adaptive Systems (RAS) to multi-system operation. A fleet of independently operating systems and a single maintenance unit are considered. It is the objective in this paper to increase overall performance or workload respectively by avoiding delay due to busy maintenance units. This is achieved by concerted and coordinated derating of individual system performance, which increases reliability. Quantification is carried out by way of a convolution-based approach. The approach is tailored to fleets of ships, aeroplanes, spacecraft, and vehicles (trains, trains, buses, cars, trucks, etc.) - Finally, the effectiveness of derating is validated using different criteria. The RAS concept makes sense if average system output loss due to lowered performance level (yielding longer time to failure) is smaller than average loss due to waiting for maintenance in a non-adaptive case.  相似文献   

6.
One of the important topics in knowledge base revision is to introduce an efficient implementation algorithm. Algebraic approaches have good characteristics and implementation method; they may be a choice to solve the problem. An algebraic approach is presented to revise propositional rule-based knowledge bases in this paper. A way is firstly introduced to transform a propositional rule-based knowledge base into a Petri net. A knowledge base is represented by a Petri net, and facts are represented by the initial marking. Thus, the consistency check of a knowledge base is equivalent to the reachability problem of Petri nets. The reachability of Petri nets can be decided by whether the state equation has a solution; hence the consistency check can also be implemented by algebraic approach. Furthermore, algorithms are introduced to revise a propositional rule-based knowledge base, as well as extended logic programming. Compared with related works, the algorithms presented in the paper are efficient, and the time complexities of these algorithms are polynomial.  相似文献   

7.
A form evaluation system for brush-written Chinese characters is developed.Calligraphic knowledge used in the system is represented in the form of rules with the help of a data structure proposed in this paper.Reflecting the specific hierarchical relations among radicals and strokes of Chinese characters,the proposed data structure is based upon a character model that can generate brush-written Chinese characters on a computer.Through evaluation experiments using the developed system,it is shown that representation of calligraphic knowledge and form evaluation of Chinese characters can be smoothly realized if the data structure is utilized.  相似文献   

8.
Ontology-Based Semantic Cache in AOKB   总被引:2,自引:0,他引:2       下载免费PDF全文
When querying on a large-scale knowledge base,a major technique of improving performance is to preload knowledge to minimize the number of roundtrips to the knowledge base.In this paper,an ontology-based semantic cache is proposed for an agent and ontology-oriented knowledge base (AOKB).In AOKB,an ontology is the collection of relationships between a group of knowledge units (agents and/or other sub-ontologies).When loading some agent A,its relationships with other knowledge units are examined,and those who have a tight semantic tie with A will be preloaded at the same time,including agents and sub-ontologies in the same ontology where A is.The proloaded agents and ontologies are saved at a semantic cache located in the memory.Test results show that up to 50% reduction in running time is achieved.  相似文献   

9.
Knowledge base grid: A generic grid architecture for semantic web   总被引:15,自引:0,他引:15       下载免费PDF全文
The emergence of semantic web will result in an enormous amount of knowledge base resources on the web. In this paper, a generic Knowledge Base Grid Architecture (KB-Grid) for building large-scale knowledge systems on the semantic web is presented. KB-Grid suggests a paradigm that emphasizes how to organize, discover, utilize, and manage web knowledge base resources. Four principal components are under development: a semantic browser for retrieving and browsing semantically enriched information, a knowledge server acting as the web container for knowledge, an ontology server for managing web ontologies, and a knowledge base directory server acting as the registry and catalog of KBs. Also a referential model of knowledge service and the mechanisms required for semantic communication within KB-Grid are defined. To verify the design rationale underlying the KB-Grid, an implementation of Traditional Chinese Medicine (TCM) is described.  相似文献   

10.
KDD中知识的自动评价系统   总被引:1,自引:0,他引:1  
How to automatically evaluate the discovered knowledge is very important in KDD,but the research on this problem is very little. The paper gives one automatic system for evaluating the knowledge, and provides many solutions. First some relative concepts are described,and the construction of this system is given,and uses the case to prove it.  相似文献   

11.
In this paper, a robust adaptive fuzzy control scheme for a class of nonlinear system with uncertainty is proposed. First, using prior knowledge about the plant we obtain a fuzzy model, which is called the generalized fuzzy hyperbolic model (GFHM). Secondly, for the case that the states of the system are not available an observer is designed and a robust adaptive fuzzy output feedback control scheme is developed. The overall control system guarantees that the tracking error converges to a small neighborhood of origin and that all signals involved are uniformly bounded. The main advantages of the proposed control scheme are that the human knowledge about the plant under control can be used to design the controller and only one parameter in the adaptive mechanism needs to be on-line adjusted.  相似文献   

12.
The Realization and Discussion of the Credit Risk Evaluation System   总被引:1,自引:0,他引:1  
This paper introduces a credit risk evaluation system of financial organization based on CBR (Case-Based Reasoning) and RBR (Rule-Based Reasoning), which combines the advantages of the two reasoning approaches. It focuses on the realization and improvement of CBR in this system, and introduces the algorithm of case matching similarity and the improvement of the case base maintenance approach, Meanwhile, it points out some questions of this system and brings forward the further study directions.  相似文献   

13.
The Real-Time Middleware is the best way to deal with open and real-time in the same time in open system. In this paper, the characteristic of open system, the policy of real-time implement in open system and the real-time CORBA specification and development are introduced, then the key technology of real-time CORBA in open system is discussed in detail according to the model of real-time CORBA including the technology of the real-time POA, real-time ORB, thread pool, pluggable network protocol, multiplexing and demultiplexing and presentation layer optimizations etc, which provides a viable method and research for open system real-time extension.  相似文献   

14.
Knowledge engineering stems from E. A. Figenbaum's proposal in 1977, but it will enter a new decade with the new challenges. This paper first summarizes three knowledge engineering experiments we have undertaken to show possibility of separating knowledge development from intelligent software development. We call it the ICAX mode of intelligent application software generation. The key of this mode is to generate knowledge base, which is the source of intelligence of ICAX software, independently and parallel to intelligent software development. That gives birth to a new and more general concept "knowware". Knowware is a commercialized knowledge module with documentation and intellectual property, which is computer operable, but free of any built-in control mechanism, meeting some industrial standards and embeddable in software/hardware. The process of development, application and management of knowware is called knowware engineering. Two different knowware life cycle models are discussed: the furnace model and the crystallization model. Knowledge middleware is a class of software functioning in all aspects of knowware life cycle models. Finally, this paper also presents some examples of building knowware in the domain of information system engineering.  相似文献   

15.
We present an overview of some recent developments in the area of mathematical modeling of maintenance decisions for multi-unit systems. The emphasis is on three main groups of multicomponent maintenance optimization models: the block replacement models, group maintenance models, and opportunistic maintenance models. Moreover, an example of a two-unit system maintenance process is provided in order to compare various maintenance policies.  相似文献   

16.
郭平  程代杰 《计算机科学》2003,30(11):40-43
As the base of intelligent system, it is very important to guarantee the consistency and non-redundancy of knowledge in knowledge database. Since the variety of knowledge sources, it is necessary to dispose knowledge with redundancy, inclusion and even contradiction during the integration of knowledge database. This paper researches the integration method based on the multi-knowledge database. Firstly, it finds out the inconsistent knowledge sets between the knowledge databases by rough set classification and presents one method eliminating the inconsistency by test data. Then, it regards consistent knowledge sets as the initial population of genetic calculation and constructs a genetic adaptive function based on accuracy, practicability and spreadability of knowledge representation to carry on the genetic calculation. Lastly, classifying the results of genetic calculation reduces the knowledge redundancy of knowledge database. This paper also presents a frameworkfor knowledge database integration based on the rough set classification and genetic algorithm.  相似文献   

17.
Based on the study of the current two methods-interpretation and compilation-for the integration of logic programming and relational database,a new precompilation-based interpretive approach is proposed.It inherits the advantages of both methods,but overcomes the drawbacks of theirs.A new integrated system based on this approach is presented,which has been implemented on Micro VAX Ⅱ and applied to practise as the kernel of the GKBMS knowledge base management system.Also discussed are the key implementation techniques,including the coupling of logic and relational database systems,the compound of logic and relational database languages,the partial evaluation and static optimization of user‘s programs,fact scheduling and version management in problem-solving.  相似文献   

18.
A rule-based expert system has been developed and used into a robotic planning system with collision-avoidance,The world model is represented as the knowledge data and stored in the knowledge base with rules.The expert system can find a collision-avoidance path.Otherwise.it shows the collision secton in which the moved object is blocked,Several examples for the different objects to pass through the different channels and to find a collision-free path have been tested.The simulating results of the palnner give out the planning sequence or blocked section(s).The output information is useful for making decision of the robot motion and modifyting the technological parameters of the world.  相似文献   

19.
In this paper, we present a general model for Arabic bank check processing indicating the major phases of a check processing system. We then survey the available databases for Arabic bank check processing research. The state of the art in the different phases of Arabic bank check processing is surveyed (i.e., pre-processing, check analysis and segmentation, features extraction, and legal and courtesy amounts recognition). The open issues for future research are stated and areas that need improvements are presented. To the best of our knowledge, it is the first survey of Arabic bank check processing.  相似文献   

20.
Update management is very important for data integration systems. So update management in peer data management systems (PDMSs) is a hot research area. This paper researches on view maintenance in PDMSs. First, the definition of view is extended and the peer view, local view and global view are proposed according to the requirements of applications. There are two main factors to influence materialized views in PDMSs. One is that schema mappings between peers are changed, and the other is that peers update their data. Based on the requirements, this paper proposes an algorithm called 2DCMA, which includes two sub-algorithms: data and definition consistency maintenance algorithm% to effectively maintain views. For data consistency maintenance, Mork's rules are extended for governing the use of updategrams and boosters. The new rule system can be used to optimize the execution plan. And are extended for the data consistency maintenance algorithm is based on the new rule system. Furthermore, an ECA rule is adopted for definition consistency maintenance. Finally, extensive simulation experiments are conducted in SPDMS. The simulation results show that the 2DCMA algorithm has better performance than that of Mork's when maintaining data consistency. And the 2DCMA algorithm has better performance than that of centralized view maintenance algorithm when maintaining definition consistency.  相似文献   

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