Knowledge object-oriented representation

Other, more advanced tools offer possibilities for combining different knowledge representations and inferencing strategies. They typically offer rules, combined with frames, different inheritance possibilities. The possibility of object-oriented programming is not always present. The user interface is not standardized and can be user tailored. The interface to standard packages is usually available. 

Object-oriented systems use the concept of reusable entities that contain both the data and procedures relevant to the object, and thus eliminating the separation of knowledge and reasoning found in expert systems. In object-oriented systems computation is behavior simulation of real-life systems. Once certain classes of objects are created, they can be reused to create other objects and properties with interface and behavior. The self-contained character of objects is known as encapsulation. Inheritance allows derivation of new objects from existent ones, and encapsulation defines the limits of services an object can provide to other objects. An example of this system is provided by GENERA,31 and a schematic representation is given in Figure 5.2. 

Because of the great variation in the details of POTW design and equipment, use of standardized data entry screens might have proved confusing to users, and would have resulted in the collection of superfluous data (both slowing system operation and taxing the memory limitations of our delivery platform). The object-oriented knowledge representation structure made possible by ALEX and Smalltalk have allowed us to implement a very flexible data entry system matched specifically to the individual POTW under analysis. An "explain" facility is available for all data requested, and default values may be used if a user is unable to provide selected plant information. 

The requirements for expert systems for process control have inspired new designs based on real-time knowledge base inferencing. Object oriented representation of plant equipment, knowledge representation of the interactions of processes and models of process behavior - heuristic as well as analytical --are incorporated into a real-time expert system for process control. The application of inference in real-time requires using metaknowledge to focus the inferencing resources of the expert system. Finally truth maintenance requires a temporal model of the time dependence of the truth of data and inferred results. 

A major result from using object-oriented approaches is that we obtain the sort of knowledge representation structures that are commonly found in many expert systems. Thus, object-oriented... 

There has been a flurry of interest over the past decade in the use of object-oriented tools that focus on the representation of human knowledge and how humans use that knowledge in reed situations to make decisions and act. An example of this approach is the Distributed Operator Model Architecture (DOMAR), developed by Dr. Michael Young of the Wright Patterson Air Force Research Laboratories and Mr. Stephen Deutsch of BBN Inc. (Young and Deutsch 1999). The system is composed of a framework of software languages and model-development tools. As with the other models discussed in this section, the intention is to provide the analyst with the necessary components to develop models that simulate both the human operators and the systems with which they interact. 

The preferred approach to railway layout representation is a broadly object-oriented decomposition, with additional knowledge structuring based on an overall Railway System Model. The purpose of the system model is to further partition and filter the large variety of information typically present within layout schematics, according to its... 

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