A DECISION-MAKING SUPPORT SYSTEM BASED on KNOW-HOW Kryssanov, V.V., Abramov, V.A., Fukuda*, Y., Konishi*, K
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A DECISION-MAKING SUPPORT SYSTEM BASED ON KNOW-HOW Kryssanov, V.V., Abramov, V.A., Fukuda*, Y., Konishi*, K. IACP, 5, Radio St., Vladivostok, 690041 Russia * TRI of JSPMI, 1-1-12 Hachiman-cho, Higashikurume-shi, Tokyo, 203 Japan [email protected] ABSTRACT decisions in the framework of a professional task with The research results described are concerned with: explanations for users. • developing a domain modeling method and tools to This is an informal classification of the systems dealing provide the design and implementation of decision- with decision-making in manufacturing. However, it may making support systems for computer integrated be helpful to realize what has already been done and how it manufacturing; corresponds with present and future trends of the • building a decision-making support system based on manufacture infrastructure. know-how and its software environment. It should be noted first, that information retrieval The research is funded by NEDO, Japan. systems are currently not discussed in the literature as Keywords: CIM, decision-making, know-how standalone programs but as a part of specialized CIM applications: CAD, CAM, CAPP, etc. There are many 1. INTRODUCTION reasons for this, and the dissimilarity of manufacturing Today, one of the important problems of Computer terminology can be pointed to as one. Another reason is Integrated Manufacturing (CIM) is to utilize the human existing retrieval systems cannot provide the freedom in experience of making decisions in a variety of professional formulating transactions necessary for CIM. tasks accumulated by leading manufacturers over the Knowledge-based systems have been developed for world, and propagate this experience by developing manufacturing for more than twenty years. Despite many appropriate computer-aided support technologies. From a limitations in the points of applicability, integration and computer science perspective, it is crucial to create a strong maintenance of the systems, research in this area is theoretical foundation and build tools to acquire, analyze considered now as a core of computer-aided decision- and synthesize the information of decision-making. making in CIM. At the same time, expert systems, which Extensive researchers’ efforts have been made on make decisions automatically, are not discussed as an understanding and formalizing the activity of decision- inevitable component of the manufacturing environment at making in the manufacturing domain since the 80s. As a present (Wada, 1996). So, hereafter we will concentrate on result, a number of systems qualified to support the activity decision support systems as well as interactive expert have been developed. These systems can be naturally systems, referring to them as DSS. classified into three categories: information retrieval A further distinction needs to be drawn between stages systems, decision support systems and expert systems. As of maturation of the support technologies for decision- no clear distinction between these categories can be found making. We will argue here that any idea concerning the in the literature, we suggest that a distinction should be technologies, to be successfully put into practice, should made based on the notions that: have an adequate embodiment on each of these three levels • an information retrieval system is a computer-based of problem awareness: 1) formal specification, 2) design, system to capture, manipulate, retrieve and transmit 3) implementation and maintenance. organized data necessary to solve a professional task To apply a formal specification technique to decision- according to detailed transactions defined by a user; making means to use a formal method having a rigorous • a decision support system is a knowledge-based mathematical basis and capable of modeling the domain in information system to capture, handle and analyze general, specifying the domain professional tasks and information which affects or is intended to affect decision- representing the domain knowledge as well. The formal making performed by people in the scope of a professional method is to provide decision support applications design task appointed by a user; with the highest integrity, reliability and compatibility. On the stage of design, it is necessary to explicate the • an expert system is a knowledge-based system to be used mathematical and program content of the technology. instead of or together with a human operator to make Taking the characteristics, which a user expects to witness conceptual. We will assume that the domain reality can be in dealing with a DSS for a basis, functionality and thought of as a potentially infinite set of separated behavior of the DSS and its software environment are situations, where each situation corresponds to a DSS run decided. made to solve a professional task. Rejecting this hypothesis Implementation and maintenance of a decision-making leads us to the conception of real-time systems that is out support technology assumes implementation of a DSS as of the scope of this paper. The situations are not linked to well as the systems to ensure the functions of updating, one another. This assertion causes the discrete updating of verification, validation and integration with external the knowledge for a DSS. Each of the situations is defined applications of the DSS which are necessary. on a finite set of domain objects, that means time and space An overwhelming majority of research reported in the frames of a situation as well as human ability to recognize a literature has been on the detailed design of decision finite set of objects within a professional task. The support systems, whereas formal specification of the professional knowledge is how people use the domain problem has still been a difficult and expensive task. Few objects to solve the task when the information about the projects have been brought to the stage of implementation objects is used as the input, output and intermediate data. and maintenance, and no attempts have been published to This knowledge, the input data and the output data for give a description of a support technology for decision- every task can be represented verbally. The latest making in CIM for all of the above levels of problem assumption is always true for input and output data (if not, awareness. decision-making support becomes meaningless), but it does The focus of this paper is on a scientific method for not interdict implicit or tacit knowledge to be used. developing and maintaining Decision Support Systems as essential components of CIM. In the following section, we 3. THE FORMALISM formulate the scope and necessary assumptions of the Let us introduce the necessary notions. method. In Section 3, an approach to modeling the domain Definition 1. An S -sorted set A is a family of sets and specifying the domain tasks is outlined. Then we ∈ = {}∈ As , one for each sort s S : A As s S . discuss some aspects of the information representation Definition 2. A many-sorted signature is a couple technique. A view of the decision-making process and a Σ Σ * × software environment to support decision-making S, , where S is the sort set, is an S S -sorted technologies are presented in Section 5. Next, the {Σ ∈ * ∈ } family a,s a S , s S of symbols, and every symbol suggested method is extended to the case of utilizing σ ∈ Σ has arity a and sort s . empirical know-how. Section 7 gives an account of an a,s experiment resulting in a DSS and its software Definition 3. An algebra of a many-sorted environment. Finally, in Section 8, we discuss related work Σ = {}∈ signature S, is a finite family A As s S of sets and draw some conclusions from our experiences. called the carriers of , conjointly with a mapping → σ ∈ Σ = ×× 2. STARTING POINTS Aσ :Aa As for each a,s , where Aa As1 Asn Despite the fact that no universal approach to decision- when a = s1 sn . making in CIM exists at present, a number of instances of Σ Σ Let X be a signature with a finite set of variables success using various knowledge-based and algorithm n techniques of making decisions for domain tasks can be X such that Σ = Σi , n > 0 , Σi Σ j = ∅ , and Σi is a ≠ found in the literature. As specification of the input and i=0 i j output of the task to be solved with a particular method is many-sorted signature with the sort set S = {}O, F, P , here still necessary to develop a DSS, these instances might be O, F and P are respectively objective, functional and considered as the knowledge (or metaknowledge) of how it predicate sorts; X = {}X s ∈ S is disjointed from Σ . is possible to get desired information under the conditions. s Such interpretation makes the knowledge-based approach Now we introduce a declarative model for representing more fundamental. However, the problem is how to the domain as the following. integrate the methods, qualitative as well as quantitative, Definition 4. A domain model Μ n of n-th order with Σ Μ n = Λ Φ within one DSS. the signature X is a tuple , such that We guess, that a basis for such integration can be a Λ = {} 0 2 n > Λ = {} 0 mapping of the domain professional activity onto a unified , , , for n 1 , and for information structure, i.e., a domain model. n = 1 ; i is an algebra of the signature Σi , We will consider that the domain is characterized by i = 0, 2, 3, ,n . The carriers A i of the algebra i , i > 1, the professional activity that consists in solving different Σ0 ⊂ 2 Σi−1 ⊂ i i ⊂ i+1 tasks (or else we will have to think about a DSS owning follow the condition: O A , A and A A encyclopedic knowledge). Solving a task takes place in the when i = 2, , n .