Computers ind. Engng Vol. 17, Nos I-4, pp. 95-100, 1989 0360-8352/89 $3.00+0.00 Printed in Great Britain. All rights reserved Copyright © 1989 Pergamon Press pie

The Design, Implementation and Evaluation of a Diagnostic Expert System for the Work Order Procedures for Smell Manufacturing Companies

Dr Kristin Kennedy Dr David Shao

Department of Mathematics Bryant College Smithfield, R. I. 02917

Department of Industrial and Manufacturing Engineering University of R. I. Kingston, R. I. 02881

Introduction Expert systems have been built for computer aided design,

computer aided manufacturing, and computer aided process planning. All three areas of research are important to creating a strong manufacturing industry, but they are all factory oriented. The analysis of office procedures has not been given equal time. With the availability of management information systems now possible for purchase, there is a need for computer aided office process planning. This process planning is difficult, because it is not a linear, straightforward activity that can be flow charted easily [Tulkoff].

By developing an expert system (ES) to help a manager analyze the offlce procedures with the intent that the ES would diagnose some problems within the office, the manager could troubleshoot some of his problems first before hiring a costly consultant. The manufacturing environment is a unique application for knowledge engineering and expert system technology, because the knowledge is primarily made up of experience, heuristics, some well-defined rules and data within the company [Zdeblick]. The output would be constructive criticisms or suggestions of improvement in much the same way that a consultant would offer suggestions. Managers often complain about the same typical problems. Thus to some degree, the problems can be generalized and handled in a generic fashion.

This research examines the possibility of designing an expert system to act as a diagnostic tool to aid a manager of a small manufacturing company examine his current office procedures in the area of order entry..One of the primary objectives of the research is to discover whether the heuristics used by managers in establishing daily office procedures could be captured by an expert system or not. Most expert systems which are on the market today are tools which were developed for only practical purposes. It remains to be seen whether the strategy of office operations can be captured effectively in an ES. It is the intent of this thesis (I) to identify rules which would make the daily office operations of a work order procedure as efficient as possible, (2) to build an expert system which would capture these rules and act as a consultant by situationally offering recommendations in this area, and (3) to evaluate the program and honestly decide if it is a worthwhile tool for businessmen.

The prototype will be designed for a job shop type of business, rather than a manufacturing firm which makes a single product on an assembly llne. Companies which use assembly llne techniques in manufacturing are typically companies which produce high volume and standardized items. These companies produce items for inventory to be sold at a later date. Thus the work order procedure is not a typical problem for them; their concerns are more centered on correcting inventory control.

The ES shell chosen for this research is Personal Consultant (PC) Easy crafted by Texas Instruments. PC Easy is based on a backward chaining approach within its inference engine, which

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means that the system operates in a goal driven manner. Backward chaining typically works best under the conditions that there exist a large number of initial conditions or facts, ~nd there exits a small number of possible solutions. Since the premise of the thesis is that every manager operates in slightly different manner, then the initial information could be quite large. By using a backward chaining system, the initial necessary data can grow to be large, and yet the systela will always cascade to the goals in the quickest possible fashion. The Aquisition of Knowledge

The work order procedure was chosen, because it can be clearly defined and can be thought of as having a starting point and an ending point. Also it is generic in that most companies would need to follow the same basic policies to maintain a healti~y operation.

After interviewing many consultants in the field, it was evident that they all had different approaches to analyzing companies. To identify a solid checklist of items, which must be checked for all businesses of the said type, would not be as easy as simply asking a few consultants in the field. The blg eight accounting firms train consultants, not only accounting consultants, but also consultants in every aspect of business. After sifting through their volumes of basic record keeping data, some form of good operating procedure was secured. Price waterhouse and Co. and Peat Marwick Main & Co. have guides to the management of small businesses, but none of the pamphlets were clear cut in terms of offering definite checklists which could easily be translated to an expert system. In fact the manuals were basically designed for new businesses. The manuals outline what information would be needed for a good work order form, but they did not specify what could be done to aid an existing business with daily problems.

The acquisition of knowledge was completed by a three step process. First, all the information the accounting firms l~ad to offer was carefully examined. Second several managers of small manufacturing companies were interviewed for their perceptlon of what the problems are and how they handle them on a day to day basis. The final step for acquiring knowledge is to te~t the expert system when completed, by giving it to several small manufacturing companies for a trial run and letting them evaluate the system. Throughout the evaluation process, additio~,s to the systems would be made. General Problems Repeatedly Identified by Business Managers

Four problems were identified as problems which are inherent to all businesses: communication, controlling cash flow, filing or updating the files, and scheduling.

poor communication results in a loss of time and a repetition of work being performed. Using the method of feedback to promote efficiency heightens the informational flow, so it is crucial to decide as clearly as possible, who needs to know what, and what feedback is important. It is a simple way of insuring a two way communication line to reduce errors, communication between departments usually involves more consu!tatlon than commands, more advice rather than instructions. Feedback insures that the advice is rightly taken and clearly understood. Feedback also insures against developing any attitude problem~.

A second major problem for small to moderately sized companies is the worry of cash flow. Two of the main reasons for this problem are that the customers are not paying their bills promptly and that the company may be over extending themselves in trying to expand and progress. In the small businesg environment it is not enough to 9ust advise that management clamp down on its customers and make them pay promptly, because small companies often deal with the same customers repeatedly. There must be general policies which a small company can use to help them control the cash flow in an efficient manner without being too harsh on their customers. The smaller company is very concerned with keeplng a customer satisfied and will tend to be more relaxed with the bill collecting rules.

If a company is cash poor because it is continually trying to modernize or upgrade itself, the company needs to slow down in its expansion process or find a way of properly financlng its

Kennedy and Shao: Expert system for work order procedures 97

endeavors. A third factor which may cause a poor cash flow would be the underprlcing of the items which the company manufactures. Market research and production\cost analysis could identify this problem.

The last two problems are filing and scheduling, however these problems within the office again generally stem from the fact that the communication within the office is poor. The two main trouble spots to focus on are cash flow problems and verbal or written interaction. The design was formulated while keeping these problem areas in mind. Designing the Expert System

A flowchart can be used to illustrate how the transition was made from the interview information to the final product of the ES.

I Initial information gathering

I Partitioning the information I •

I Programming the rules I

I Eva ou on of the program I

yes

When an evaluation was performed, it was established whether to modify the program or not. Thus a loop was formed back to partitioning, whenever modifications were needed.

Partitioning of the information was the most important phase of the design. The information taken from the interviews needed structure before any system rules could be developed. It quickly became clear that to develop a questioning which would lead to one general recommendation for the work order procedure was impossible. The procedure had to be partitioned into subsections.

Each subsection encapsulated one idea which was important to the entire procedure of work orders. In most cases there were several questions which required an answer before a recommendation could be assigned for one subsection. All the questions had several possible answers to choose from, so depending on how the questions were answered, different recommendations could be assigned to one subsection. The work order process can actually be a very slippery process to track. Four principal concerns repeatedly emerged as main worrles which are faced on every order: (I) establishing whether the customer's credit was good or not, (2) establishing a fixed price for the order, (3) setting a valid lead time, and (4) making sure that the customer agreed to the set price and lead time. The subsection which is concerned with establishing a customer's credit was broken down into three smaller subsections, that of (I) setting a limit, (2) updating a limit, and (3) verifying that the limit is actually used. The subsection concerned with fixing a lead time was also broken down to two further subsections, that of (1) contacting all necessary departments and (2) checking all t h e f i n i s h e d goods s u p p l i e s .

Each one o f t h e s u b s e c t i o n s wou ld have i t s own r e c o m m e n d a t i o n

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at the end of a session. Furthermore, each subsection had its own llst of concerns which the ES would have to query before arriving at a recommendation. The list of concerns would be transformed into the questions the ES would use. How the questioning process was to proceed would take more massaging of the information. Order had to be given of all the questions which could be derived from the concerns which the managers and the consultants stated.

There are two ways to graphically imagine how the information gleaned from certain questions leads to different conclusions. One diagram, which at first glance seems to represent how the information leads to a conclusion, is the star diagram. Each separate arm of the star represented information which the system needed before reaching a conclusion for a subsection. All of the separate pieces of information lead to one conclusion. For example one of the subsections under the work order procedure is that of fixing a price for an order. There would be one recommendation as to whether the company checks all appropriate information before determining a price. There are five areas of concern for this recommendation: I) is the design department contacted, 2) is the purchasing department contacted, 3) is any discounting available, 4) is there a check to see if any of the materials come from a volatile market, and 5) is a check performed on the accumulated cost book. Thus a star design would have five arms on the star, and all of the information from all five lead to one conclusion. five lead to one conclusion.

(2)

Star design

The star design is faulty. It gives one the impression that every branch of the star represents a question which must have an answer. The impression is that if one branch is not answered, then the recommendation cannot be reached. That is a falsehood. In fact it can happen that if a few of the branches are answered with 100% confidence, then the recommendation can be reached very quickly. It is not always necessary to answer all the questions. Also some questions have precedence over others. If they are answered in a way which would require a strict recommendation, then some other less important questions could be skipped.

A better design is a transition diagram, which clearly reflects the linear flow of information which the system would request before reaching a conclusion. Each node in the diagram represents a piece of information which is needed before a recommendation can be set. Sometimes that information cannot be acquired by one simple question; it might take two or three questions to clarify the answer. Thus a loop is formed in which the system might ask several questions about a piece of information before moving on to the next piece of information which is needed. Also depending on the outcome of the questioning process, the transition diagram can be designed to branch to other nodes, while skipping some others. The questioning process does not have to go through every node. The transition diagram allows for the design of skipping some questions in certain instances. The transition diagram for the subsection of determining a price might look something like the diagram below.

Transition diagram

As the system grew larger through evaluations and review, the partitions and the transition diagram simplified the process of

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incorporating more information into the program. There are three possible ways to modify the system: I) add another answer to an existing question, which does not change the transition diagram, it simply gives the system another choice for a value of a parameter, 2) add a new question to an existing set of questions in a subsection, which graphically either expands the diagram by adding another node or it simply creates more looping on a certain node of information, 3) divide the existing transition diagram into two separate smaller transition diagrams, which in effect is creating a new subsection.

The partitioning created an easy management concerning the growth of the system. After several evaluations were completed, the review of the evaluations would identify what common critiques were mentioned. Those would be the new additions to the ES. Capabilities of the Expert System

The qualities which the system features are: 1) it represents the daily procedures as a logical unit, 2) it standardizes the daily procedures for one type of business, 3) it offers the user suggestions of improvement, which he simply may never thought of, 4) it forces the company to scrutinize its current operating procedures and verify exactly why something is or is not done, 5) it minimizes the user's efforts, when running the program by requiring only simple answer selections as yes\no, and 6) when more complicated answers are necessary to identify other skills, the user is still allowed to make selections from a type of menu; the user is able to avoid writing any type of sentence in answering the questions, which would be time consuming.

The ES does not give an example of what a work order actually looks like. There is a certain core of information which should be requested on an order entry form. For any company in the early stages of formation learning how to set up an efficient order entry is very important. However, the diagnostic tool constructed from this research is a tool for an existing business, which has been in operation for several years and is growing. The basic format which the company uses should be well established. To find the true problems in the procedures, one must look deeper than simply examining what information is requested on the forms. Implementation

The program was implemented using PC Easy as a shell quite successfully on an IBM PC XT. The programs are designed to have simple atomic answers to all of the questions. Many questions are answered by either yes or no. Others which required some explanation employed the F1 key. The user was to select 3ust a number as his answer. When the F1 key was implemented, another window appeared on the screen stating descriptions of what each number meant. Thus the user could select an answer in some detail, yet internally the program was assigning a single value to a parameter.

The creation of the program evolved from an initlal development to a final product by modifications which sprang from evaluations performed by businessmen. Seven evaluations were performed, and each one gave some response which made it a unique evaluation; however any modifications which resulted from an evaluation had to be clearly scrutinized before they were implemented. It had to be determined that the modification brought a new idea into the program which was true generically for many businesses, not just the one performing the latest evaluation. These seven evaluations which effected several modifications to the system illustrate how the program was developed by looping through the flow chart above.

For example, after the first design was completed, many of the questions simply required a yes\no answer. Several of the businessmen wanted the selection of "sometimes" in addition to the yes\no selection. By adding this to the selection of answers, new questions also had to be generated so that when a user chose "sometimes" through another question, he could explain why he chose "sometimes". Thus the comment made by the businessmen changed the system by adding a new selection to an answer menu of one question, and it created a new question used for clarification purposes. The question which was created

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represents a return to a node in the transition diagram. Advantages of the Expert System

The use of an ES clarifies the knowledge of the domain. Office problems exist not because the managers are not smart enough to identify them or to define a solution, which often is an obvious solution to any other arbitrary person, but they exist because the manager is too close to the problem, or he simply does not have time to quietly sit down and examine his office procedures. The use of the expert system clearly states the knowledge of the domain, and the ES can produce a written record of a consultation, which can be a great reference tool at a later date. The ES gives logical orde; to daily operating procedures. These procedures are shown as a logical units rather than as discrete processes.

The ES under the same conditions will always produce the same response. There exists a consistency within the system. That is not true of a human consultant, who could give an answer due to favoritism or politics. Also the ES can be used at any time convenient to the user. After a manager runs the program answering the questions as pertains to his own business, he then can play the devil's advocate. He can run the program again, asking what if types of questions, and getting a different perspective on his operations. Another advantage is the low cost of using such a system. Consultants are very highly paid individuals today, and there are many who are not worth the price. The use of an electronic consultant would greatly reduce the cost of consulting. At the very least the ES could ldentify generic or basic office problems, which would be a great help to many. The human consultants then could concentrate their efforts to problems which are specific to singular businesses.

There originally was a concern that an office manager would prefer to interact with a consultant than with a machine. Some managers greatly preferred the electronic consultant, because they felt that they could accept or reject a recommendation without worrying about people's feelings. With an electronic consultant one avoids the human factor, which can add prejudice in making a decision. Most of the people viewed the ES as a tool which could be used either as a quick check before a consultant is hired, or as a tool which the consultant would use to get all overview of the business and to trigger questions for other areas of discussion.

Finally all the managers felt that the system was very easy to use. The questions were straightforward, and when an explanation was needed, the help key clarified the question. Also the managers enjoyed answering in one word answers; it added a degree of speed to the consultation, which they liked. Those who had no computer experience were able to run the program efficiently with only one trial run. Furthermore they found it to be great fun. The final recommendations which the program gave as output were given high grades. They were concise and they covered the major points which an auditor would cover.

BIBLIOGRAPHY

Hammer, Michael; "Strategic Planning for Office Information Systems"; Management Technology; June, 1983, pg. 28 -34.

Hewitt, Carl; "Offices are Open Systems"; ACM Transactions on office Information Systems; vol. 4, no. 3; July, 1986; page 271 - 287.

O'Keefe, Robert, Belton, Valerie, and Ball, Theresa; "Experiences with Using Expert Systems in O.R."; Journal of Operational Research Society; vol. 37; no. 7; 1986; page 657 - 668.

Tulkoff, Joseph; "Process Planning: an Historical Review and Future Prospectm"; Proceedings on Computer Aided Process Planning; Penn State; June 1-2,1987; pg. 207 - 210.

zdebllck, William; "Process Planning Evolution: the Impact of Artificial Intelligence"; Proceedings on Computer Aided Process Planning; Penn State; June 1-2, 1987; pg. 175 -179.