首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
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.
The traditional resasoning system based on first order predicate logic can‘t represent and handle default knowledge,This paper presents a logical framework representation approach for default reasoning.Based on Mixed SLDNF-resolution,a nonmonotonic reasoning system has been constructed.  相似文献   

3.
This paper deals with the problematic of development methodologies for organisational information systems and especially with their application to business systems. Historically, information systems development methodologies tend to fail, because either they take the organisational purposefulness for granted, or they do not analyse it thoroughly. This paper's position is that the analysis, and the definition or redefinition of the systemic purpose are regarded as the utmost expression of the system's purposefulness. This is to be achieved by ensuring the participation of all the stakeholders who affect, or are affected by, a particular business system's operations. The nature of participation, defined as a process of the stakeholders' perceptual exchanges, is deemed to be problematic in itself, due to the influence exerted upon it by organisational power, coercion and false consciousness. The paper highlights the philosophical reasons for the failures of information systems development methodologies, and provides a conceptual solution to this problematic as well as a strategy for the development of intrinsically motivated organisational information systems. The intrinsically motivated information systems methodology outlined here (BSPA) is intended to yield organisational information systems that demonstrably improve co-ordination of organisational activities, by enabling the development and maintenance of a single/multifaceted view of purpose throughout organisations.  相似文献   

4.
5.
We are obtaining a large database of some objects' records of fluctuations of a stock market,medical treatments,changes of weather in certain area and so on,where each record consists of multi-attributes taking multi-values changing with time. Our work is motivated by prediction,which is different from the work in 4,5,8,11. We want to help learn from past data and make informed decisions for the future. This paper is very significant to perfect the theory and the development of the temporal data mining.  相似文献   

6.
A Real-Time Wireless Distributed Embedded System (RTWDES) is formed by a large quantity of small devices with certain computing power, wireless communication and sensing/actuators capabilities. These types of networks have become popular as they have been developed for applications which can carry out a vast quantity of tasks, including home and building monitoring, object tracking, precision agriculture, military applications, disaster recovery, industry applications, among others. For this type of applications a middleware is used in software systems to bridge the gap between the application and the underlying operating system and networks. As a result, a middleware system can facilitate the development of applications and is designed to provide common services to the applications. The development of a middleware for sensor networks presents several challenges due to the limited computational resources and energy of the different nodes. This work is related with the design, implementation and test of a micro middleware for RTWDES; the proposal incorporates characteristics of a message oriented middleware thus allowing the applications to communicate by employing the publish/subscribe model. Experimental evaluation shows that the proposed middleware provides a stable and timely service to support different Quality of Service (QoS) levels.  相似文献   

7.
In this paper,a framework is presented for adding a general command recovery facility to user interface.A simple model of interactive system is discussed and four meta commands.UNDO,REDO.SKIPBACK,and SKIPFORWARD,are defined.The double-linked list is used to organize the recovery information in a natural way for easy implementation.Applications of the framework to various demands of command recoveries show that the use of the framework is veryeasy and convenient.  相似文献   

8.
9.
It is argued that recent research in the information systems field has tended to either emphasise the structural/collective dimension or the agency/individual dimension, not both. Structuration theory is a more recent attempt to address both agency and structure, however there are a number of issues with the use of structuration theory in information systems research, not the least of which is its lack of recognition of the temporal and longitudinal nature of information systems development. A relatively new philosophy, critical realism, provides the potential for a new approach to social investigations in its provision of an ontology for the analytical separation of structure and agency. The philosophy is introduced and its implications for sociological investigation are discussed.  相似文献   

10.
Networked control system is a new hot-point in control engineering. The reduction of bandwidth necessitated by the communication network in a networked control system is the major concern. For this reason, a method of reducing the number of data packet exchanges between the sensor and the controller/actuator is explored. A novel structure of controller and special transmission rule are designed for reducing the number of data packet exchanges and making the system stable.  相似文献   

11.
This paper presents a recovery technique for distributed communicating processsystems.It handles both hardware faults and software faults uniformly.Differing fromother recovery techniques,it brings an extremely small amount of execution overheadto nonfailing processes and can be implemented easily.It can be applied to aprogramming procedure to mask the software design errors or imbeded into anoperating system to enhance the reliability of the whole system.The theoretical workis carried out first,then the implementation problems are considered and theevaluation techniques are discussed last.  相似文献   

12.
13.
Introduction A number of universities have recentlystarted to add baccalaureate programs inInformation Technology(IT)to their existingprograms in Computer Science(CS)and(Management)Information Systems(IS).Whilesome have welcomed this development,othersare less accommodating.The argument that ITbaccalaureate programs are not sufficiently distinctis most often heard from faculty in programs inComputer Science(CS)and(Management)Information Systems(IS).The argument isoften two-fold.First…  相似文献   

14.
The concept Lean Web Automation (LWA) describes a new approach for web-based operation of automation devices in distributed systems, which can be used flexible by means of compact and low-cost software without installation expense on the client side. A dynamic process data transfer in the TCP/IP network is implemented by a javabased application model. This model uses a process data proxy to create at web clients an interface to process data of a remote automation device. A first practical …  相似文献   

15.
It is desirable in a distributed system to have the system load balanced evenly among the nodes so that the mean job response time is minimized.In this paper,we present a dynamic load balancing mechanism(DLB).It adopts a cntralized approach and is network topology independent.The DLB mechanism employs a set of threscholds which are automatically adjusted as the system load changes.It also provides a simple mechanism for the system to switch between periodic and instantaneous load balancing policies with ease.The performance of the proposed algorithm is evaluated by intensive simulations for various parameters.Te simulation results show that the mean job response time in a system implementing DLB algorithm is significantly lower than the same system without load balancings.Furthermore,compared with a previously proposed algorithm,DLB algorithm demonstrates improved performance,especially when the system is heavily loaded and the load is unevenly distributed.  相似文献   

16.
17.
The information systems with incomplete attribute values and fuzzy decisions commonly exist in many applications whose knowledge reduction is one of the most important practical significance. Model of incomplete and fuzzy decision information system is firstly constructed. On the basis of the notion of inclusion degree between fuzzy sets, the attribute reduction for incomplete and fuzzy decision information system, which ensures invariable inclusion degree between every tolerance class and fuzzy decision set, is raised. To reduce the complexity of finding attribute reduction, discernibility sets, discernibifity matrixes and the minimal disjunctive normal form of discernibility sets for incomplete and fuzzy decision information system are introduced. Finally, the algorithm and an example are given, and the solution of the example is proved that the approach to attribute reduction based on inclusion degree is valid.  相似文献   

18.
A Framework for Commercial Grids—Economic and Technical Challenges   总被引:2,自引:0,他引:2  
This paper argues that the technology of Grid computing has not yet been adopted in commercial settings due to the lack of viable business models. While in academia Grid technology has already been taken up, the sharing approach among non for-profit organizations is not suitable for enterprises. In this paper, the idea of a Grid market is taken up to overcome this Grid adoption gap. We propose a framework for building up a Grid market and identifies the associated economic and technical challenges. Based on this framework, we identify a catalogue of possible market mechanisms which offer a promising fit to the Grid environment’s characteristics and which may thus help to carry the idea of Grid markets from theory to practice.  相似文献   

19.
In this paper, we present feature/detail preserving models for color image smoothing and segmentation using the Hamiltonian quaternion framework. First, we introduce a novel quaternionic Gabor filter (QGF) which can combine the color channels and the orientations in the image plane. We show that these filters are optimally localized both in the spatial and frequency domains and provide a good approximation to quaternionic quadrature filters. Using the QGFs, we extract the local orientation information in the color images. Second, in order to model this derived orientation information, we propose continuous mixtures of appropriate exponential basis functions and derive analytic expressions for these models. These analytic expressions take the form of spatially varying kernels which, when convolved with a color image or the signed distance function of an evolving contour (placed in the color image), yield a detail preserving smoothing and segmentation, respectively. Several examples on widely used image databases are shown to depict the performance of our algorithms.  相似文献   

20.
A Frame Based Architecture for Information Integration in CIMS   总被引:1,自引:0,他引:1       下载免费PDF全文
This paper foumulates and architecture for information integration in computer integrated manufacturing systems(CIMS).The architecture takes the frame structure as single link among applications and between applications and physical storage.All the advantages in form features based intgrated systems can be found in the frame-based architecture as the frame structrue here takes from features as its primitives.But other advantage,e.g.,default knowledge and dynamic domain knowledge can be attached to frames and the frame structure is easy to be changed and extended,which cannot be found ing form reatures based systems,can also be showed in frame based architectures as the frame structure is a typical knowledge representation scheme in artificial intelligence and many researches and interests have put on it.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号