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United States Patent [i9]
US005548714A [li] Patent Number:  Date of Patent:
 MEANS FOR STRUCTURING TECHNICAL INFORMATION IN ESTABLISHING A KNOWLEDGE BASE AND TROUBLESHOOTING IN TECHNICAL EQUIPMENT
 Inventor: Hans Becker, Sollentuna, Sweden
 Assignee: Televerket, Farsta, Sweden
 Appl. No.: 30,068
 PCT Filed: Sep. 18,1991
 PCT No.: PCT/SE91/00625
§ 371 Date: Apr. 2,1993
§ 102(e) Date: Apr. 2,1993  PCT Pub. No.: WO92/05503
PCT Pub. Date: Apr. 2,1992
 Foreign Application Priority Data
Sep. 21, 1990 [SE] Sweden 9003009
 Int. CI.6 G06F 11/34
 U.S. CI 395/183.02; 395/12; 395/911
 Field of Search 395/575, 10, 12,
395/51, 52, 911, 912, 916, 183.01, 183.02
 References Cited
U.S. PATENT DOCUMENTS
4,954,964 9/1990 Singh '. 364/514
4,964,125 10/1990 Kim 364/513
5,107,497 4/1992 Lirov et al 371/15.1
5,107,499 4/1992 Lirov et al 395/911
FOREIGN PATENT DOCUMENTS
8802543 7/1988 Sweden. 2190772 11/1987 United Kingdom. WO90/00776 1/1990 WIPO .
Proceedings of the International Test Conference, The Computer Society of the IEEE, M. Ben-Bassat, et al., pp. 78-86, "A Proposed Benchmark Unit For Evaluating Electronic
A system and a method for structuring technical information in establishing a knowledge base and trouble shooting in technical equipment. An intelligent, electronical document is created in the quickiest and most efficient way for guidance training and troubleshooting of complex technical equipment. The required concepts are defined which are capable of describing states in a knowledge base, node types are defined indicating what type of information or instruction a node is to contain, views are read containing pictures or graphic descriptions of the equipment, nodes are inserted into the views to provide access points to various parts of the equipment, at least one of the nodes being a rule node containing at least one rule. The rule contains a condition part and a conclusion part, the condition part consisting of conditions on the equipment and the conclusion part containing measures to be taken if the conditions are fulfilled. The method and system are primarily used by developers and troubleshooters. The developers contribute with knowledge about technical equipment and with practical knowledge, such as rules of thumb. The troubleshooters can use the system without specific previous knowledge to perform troubleshooting, being systematically guided by the system to the source of failure.
MEANS FOR STRUCTURING TECHNICAL INFORMATION IN ESTABLISHING A
KNOWLEDGE BASE AND TROUBLESHOOTING IN TECHNICAL EQUIPMENT
FIG. 2 shows an example of a view with nodes on a computer screen, and
FIGS. 3A and B show symbols for picture nodes and text nodes, respectively.
BACKGROUND OF THE INVENTION
1. Field of the Invention 10 The invention relates to a means and a method for
structuring technical information and is a development envi-
ronment designed to enable construction of an intelligent,
electronic document in the quickest and most efficient way
for guidance, teaching in a complex technical equipment. On 15
a computer screen is shown what previously has been in
manuals: block diagrams, circuit diagrams, photographs and
instructions. An experienced technician uses the invention to
find information about measurement results or sources of
failures. A technician without computer experience can 20
quickly learn to develop advanced systems. In troubleshoot-
ing, an unexperienced technician is guided by the invention
through the technical equipment until the fault is located.
2. Description of the Background
Expert systems have been custom-designed for specific
technical objects. In contrast, the present invention provides a general method of structuring a knowledge base and of helping users without specific previous knowledge.
SUMMARY OF THE INVENTION
Thus, the present invention provides a means and a method for structuring technical information in establishing a knowledge base for handling guidance, teaching and 35 troubleshooting of technical equipment. According to the invention the required concepts are defined to describe states in the knowledge base. Node types are defined indicating what type of information/instruction a node is to contain. Views are read containing pictures or graphic descriptions of ^ the equipment. Nodes are inserted in the views to provide access points of various parts of the equipment, at least one of the nodes being a so-called rule node containing at least one rule having a condition part and a conclusion part. The condition part consists of conditions of the equipment and 4J the conclusion part contains measures to be taken if the conditions are fulfilled. The knowledge base is divided into blocks, if necessary, a base block containing information common to all the blocks and information about linking of the blocks. 50
When troubleshooting in a knowledge base in accordance with the invention, first the starting block is chosen, whereupon a starting view is shown. Then it is possible to choose a new block, anew starting view being shown, choose a new view within the block in question and/or to choose a new 55 node in the view in question to proceed. A rule node is chosen to obtain instructions about what measures are to be taken, the instructions being followed until a conclusion is reached. If further information is desired a new text node or picture node is chosen. 60
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in detail with reference to the accompanying drawings, in which 65
FIG. 1 shows the general structure of the invention with external and internal communication,
DETAILED DESCRIPTION OF THE
The invention provides an expert system structure for diagnosis, in other words a tool especially designed to build expert systems. Using the invention a person without any experience of programming or expert systems can build a diagnostic system. The system is useful for technicians performing troubleshooting in complex technical equipment. The diagnostic system collects knowledge from one or several experienced technicians. The knowledge is represented in rules guiding the troubleshooter to the source of the problem. The invention shows graphic circuit diagrams, block diagrams and photographs of the test equipment to provide the user with other relevant information.
The invention is in principle constructed like ordinary expert system structures. However, in contrast to these, considerable effort has been invested in making the user and expert interfaces user friendly. Besides these two interfaces there is a knowledge base with rules and facts. An inference machine draws conclusions based on the contents of the knowledge base.
FIG. 1 shows schematically the structure of the system in accordance with the invention. There are two main groups using the invention, developers and troubleshooters. The developers enter diagnostic knowledge through the expert interface into the knowledge base. The troubleshooter has access to the knowledge base by means of the user interface and the inference machine.
The interfaces present views to the users to give access to the information. An example of such a view is shown in FIG. 2. A view is a description of the object being diagnosed. Typical views are photographs, block diagrams and circuits schematics. Attached to views are nodes which contain rules.
When troubleshooting, the service engineers navigate between test points before they arrive at the source of failure. The test points are often documented in service manuals. The manual states which value a test point should have when the equipment is functioning correctly. According to the invention, nodes are used instead of test points. A node can be a test point but also a physical object like a button or a fuse. Every node contains rules which lead the troubleshooter closer to the source of failure. The troubleshooter studies the view and selects a node suitable for inspection. When the node is selected further information or instructions are obtained, as is explained in detail below.
Some nodes contain only information and may be of the types picture nodes or text nodes. In FIGS. 3A and 3B the symbols are shown for picture nodes and text nodes, respectively. These can be placed in views in the same way. When the user selects a picture node he gets a graphical display on the screen, and when he selects a text node a text window is displayed. The text window allows for editing text.
According to a preferred embodiment of the invention the information should be structured in the following way.
Concepts are objects defined globally in the knowledge base and are used to define attributes, see below. From one and the same concept several different attributes can be defined. Each concept has a name and a domaine and may