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Teaching of a case study for expert systems

construction

A. Sierra-Alonso,* N. Medinilla

*Departamento de Informdtica, Escuela Politecnica Superior,

Universidad Carlos III, C/ Butarque 15, 28911-Leganes, Madrid,

Spain

Departamento de Lenguajes y Sistemas, Facultad de Informdtica,

Universidad Politecnica de Madrid, Campus de Montegancedo,

28660-Boadilla del Monte, Madrid, Spain

E-Mail: [email protected], [email protected]

Abstract

Knowledge Based Systems (KBS) were born recently (compared with other software type)and there are no guidelines for teaching them. Usually, the students have to face with realproblems without enough preparation. They solve small examples in the classroom and then,they develop a real project. A smooth transition between examples and project is necessary.This paper discusses a Case Study that serves as a transition between what the students learnin classroom and the real world problems. We take into account other educationalexperiences in KBS and a total quality model for expert systems.

1. Introduction

Knowledge Based Systems were born recently (compared with other softwaretype) and arrived to the university education about a decade ago, due to theirimportance [13, 16]. But mathematics, which arrived several centuries ago, arebeing taught daily in the schools, and nevertheless they still arise large polemicsabout how to teach them. Therefore, it is too soon to formulate guidelines forhow teaching to develop KBS. Maybe it results more valuable to explainparticular experiences. This work deals with one of these experiences.

A Master Degree (MSc) in Knowledge Engineering is offered since 1987 atthe School of Computer Science of the Universidad Politecnica de Madrid(UPM) [14]. The MSc lasts for seven hundred hours. During five hundredhours, analysis and design techniques and a KBS development methodology aretaught. Next, during two hundred hours or more, the students should make afinal project (FP) to obtain their degree. But the leap from learning thetechniques to the accomplishment of their FP is too large. The student has to

Transactions on Information and Communications Technologies vol 14, © 1997 WIT Press, www.witpress.com, ISSN 1743-3517

48 Software Quality Engineering

integrate the techniques they have learn isolated to shape and build the wholeproject. But this integration has to be made before the student has got a goodgrasp of the techniques. This leap supposes a very large effort for the studentand the supervisor.

The objective of accomplishing a case study in the classroom is to obtain amore smooth transition: this is, including a step between the learning of thetechniques one by one and their integrated application for the project. A stepthat should help to strengthen the acquired knowledge in the preceding subjectsand, furthermore, it should begin to integrate this knowledge in a developmentmethodology. The Case Study should also encourage the teamwork, toapproach a part of the social aspect, inherent to the software systemsdevelopment in general and of KBS in particular.

In the year 94 a case study was developed in the classroom, as the last partof the lectures. It was designed taking into account a previous experience andfrom a real KBS. Stimulated by the satisfactory results, the effort of formalizingthis teaching was accomplished, to improve the educational performance of thesubject Case Study This work has taken several courses and it has consist of:the design of the subject, the development of a complete KBS prototype thatserves as connecting theme of the subject and the elaboration of the teachingmaterial, based on the prototype documentation, where each stage of thedevelopment is discussed step by step, from the viability test to the evaluation.

In this paper we consider what the Case Study provides to the knowledge ofthe domain of KBS and, furthermore, what it provides to the mathetic of thesesystems. Papert [12] coined the term mathetic to designate the learning art

In this paper a previous development experience of a case study in the MScis analyzed. The new proposal of the Case Study is explained, discussing thetheoretical and practical considerations that the authors took into account forthe design, development and teaching of the Case Study. Afterwards, theresults of applying the new Case Study design are analyzed.

2. A previous experience

The idea of developing a case study in the MSc is previous to the workpresented here. Bellow, a previous experience with a Case Study is analyzed.

A case study development was proposed using IDEAL methodology, whosephases and stages are showed in Table 1 [7]. The development took place inthe classroom. The students were considered, together, as a development team.With the aim of getting the real conditions, the interviews were simulated withrecordings and lectures attempted to emulate technical meetings, where theteacher would act sometimes as a consultant, other times as an expert, but notas a tutor. Students had to produce the system documentation too

The first phase of the methodology (see Table 1) was developed by eachstudent individually. With the second phase of the methodology (see Table 1)the work dynamics changed The students were organized as a technical team,split into working parties to face the different stages of this phase The lecturermaintained the exclusive consultant role.


Software Quality Engineering 49

PHASESI- Application Identification

II-DemonstrationPrototype Development

Ill-Other PrototypesDevelopment (Research,Field, and Operational)IV-Full SystemConstructionV- System Maintenance andProper TechnologyTransfer

STAGES

-Requirement Plan-Application Evaluation, Selection and Definition-Solution Conception-Knowledge Acquisition and Conceptualization-Knowledge formalization-Tool selection and implementation-Validation and Evaluation-Definition of New Prototype-Knowledge acquisition to Validation andEvaluation of New Prototype-Integration with other Software and Hardware-Acceptance Test by Client-Maintenance of the System and Knowledge Base-Organize technology Transfer-Complete KBS Documentation

Table 1: IDEAL Methodology Phases and Stages

The plan bumped into a severe difficulty: a generalized confusion betweenthe students was produced, practically, during all time A notable reduction ofthe results turned out with respect to the initial objective. Probably, theconfusion emerged because the learning was forced: the students were obligedto develop their own resources, starting from what they had learnt in theprevious subjects. But, the students did not have enough maturity to integratethe acquired abilities, in a short time and by themselves. The absence ofappropriate documentation aggravated the problem

From a few years ago, a trend exists toward an education that emphasize thefactors of learning [5, 8, 10, 11, 20]. This experience of Case Study is withinthat line, but the students possibilities were overvalued and the teaching meansto support the learning were undervalued.

This experience made explicit that the acquired capabilities by the studentsuntil that moment, were insufficient to approach the FP, with the requiredindependence. It confirmed the convenience of a Case Study as intermediatestep before the FP.

On the other hand, the dedication of each group to an only stage of thedevelopment, trying to imitating a real experience, encouraged a specializationthat was conspiring against the wished abilities integration. Furthermore, thisproduced an imbalance in the work intensity of each group.

Finally, a so sequential division of the stages was not adequate for theevolving prototype life cycle that is adequate for KBS development [1]. It wasnot possible, or at least very difficult, the feedback between the stages,fundamentally between knowledge acquisition and conceptualization.



3. A new approach to the Case study

As an overview, the learning of abilities occurs, according to Anderson [2], inthree stages:

r Cognitive stage: a procedure description is learnt.2° Associative stage: we work with a method to develop the ability.3° Autonomous stage: the ability is made faster and automatic.During the second stage people convert their declarative, factual knowledge

of a domain into a procedural, more efficient representation. The tacticallearning prevails, where the students learn the step sequences to solve theproblem or parts of the problem. In the third stage the strategic learningappears. Here, how to organize the complete problem resolution is learnt [2].

The course of MSc encompasses the first two stages and begins the third,with the FP. When the lectures are finished, it can be supposed the studentsknow the elements which constitute the KBS development and have someprocedural representations of them.

The preceding experience of the Case Study in the MSc showed that, in thatstage of the course, the tactical learning is still insufficient and the strategiclearning of the development of the KBS has not begun. In such conditions, ifthe students approach directly the FP, they are obliged to learn in a way thatwould consume much time and effort by students and supervisors.

But, if a case study is developed before the FP, there is a softest transition.The strategic learning would begin before and the project would be a means ofreinforcing it, because then, it is the second time the students are faced to thecomplete problem.

3.1 Educational considerations

Teaching and learning ideas are very overlapped in our language. So much, thatit is easy to confuse ontologically dependent relationships with causalrelationships. Due to the fact the teaching idea depends on the learning idea,and due to the fact the learning is produced after the teaching with muchfrequency, the learning is a consequence of teaching can be thought [6].However a slope to focus the current education from the point of view of thelearning is being produced [5, 8, 10, 11, 20].

The Case Study in the MSc fulfills a content function, because it is part ofthe matter the students should learn: the strategy of the KBS developmentprocess and how that strategy is displayed teamwork

The Case Study also fulfills a mathetic function. In the constructionism,Papert's particular vision of Piaget's constructivism, a basic mathetics principleis the following: the construction that takes place 'in the head' is improved if itis accompanied by the construction of something 'in the world'. What he meanswith 'in the world' is that it is possible to analyze, to examine and to investigatethe concrete object [12]. In the Case Study, the prototype is a concrete objectin the world that can reinforce the KBS image we have 'in the head'. When theCase Study is reached, the students only have the vision 'in the head' and,


Software Quality Engineering Ji

perhaps, a vision 'in the world' of some parts, but not a global vision.On the other hand, the most conscious part of learning consists of

establishing connections between mental entities that already exist [12]. Thedevelopment process of the Case Study should encourage the establishment ofthe connections between mental entities that the students have of the elementsand the KBS development stages.

All these features are not exclusive of the Case Study. The FP also has them,but with a much greater dimension and therefore, with different objectives andmethods. Furthermore, in the FP the student works mainly on her/his own andin the Case Study the student is guided by the teacher. The authors believe theCase Study and the FP are two successive steps in learning. Dispensing withthe former supposes using a highest step for the latter.

In terms of content, the Case Study deals with the KBS developmentlearning, the integration of the parts as a whole, the complete vision and thesocial side of the KBS development. From the mathetic point of view, the CaseStudy fulfills the function of producing the first KBS as a concrete object andto facilitate the mental connections establishment.

In terms of content, the FP deals with reinforcing the strategic learning ofthe KBS development, initiated in the Case Study, but with a much greaterdimension of the problem space. The student has to be faced with that changingreal problems and the real social subsystem where the system development isintegrated. These features distinguish deeply the FP of the Case Study.

3.2 Multidimensional Case Study

One of the first problems is establishing the features of concrete Case Studythat will be developed in class.

Sharma and Conrath suggest a total quality model for expert systemsevaluation with two dimensions [17]: technical and social. The technicaldimension is referred to the nature of the task and to the technology used tosolve it The social dimension concerns to the division of the work and itscoordination. Davis says: "good management is more important than goodtechnology"; and, furthermore: "people are the key to success" [4]. We think,there is no doubt with respect to the interdependence of the results with socialand technical factors. Therefore, describing the Case Study with these twodimensions, using the model of Sharma et al. seems adequate.

In the Case Study, as part of the technical dimension, the task characteristicsto solve are analyzed and the technology to used is decided. The socialdimension is reduced to the students and to the teacher. The interaction withdirectors and users is not possible due to the educational environment featureswhere the Case Study is developed. But teamwork is made to encourage thesocial interaction between the members of a working party.

3.3 Task

The following difficulty is: What problem to solve with a KBS to achieve theproposed educational objectives?



It is necessary that the elected problem motivates to the students. Pilgrimachieves to motivate to students between eleven and fourteen years with thegame Tic-Tac-Toe, in an introductory course of expert systems [15]. But thisgame results too simple for older students that can lose the interest in aproblem if they estimate that it is little important [21]. On the other hand, toocomplex problems do not be achievable in class by the time limitations and theycan surpass the students capacities and discourage instead of encouraging.

Below, some alternatives for the task of the Case Study are studiedconsidering time and objectives:• Taking a real problem coordinated with a company offers the possibility ofknowing and facing the customary difficulties in the KBS development [9,19, 20]. But the step by step approach to the reality would not be producedThis is more adequate for the FP.

• Simulating real cases, instead of facing a real problem, deprives the studentsof the confrontation with some systems development difficulties [20]. But tointegrate abilities and concepts, as a previous step to the FP, the absence ofthose difficulties is not a severe restriction.

• Using cases which already solved to analyze them is another possibility [3]But one of the Case Study objectives is to acquire construction abilities, soit is not adequate, because the students will not see how to build the case.

• Using traditional exercises so that the students focus on certain aspects ofthe KBS development [22] is not a good alternative, since integrating theabilities of the whole process is wanted.

• Inventing a case has the advantage of its easy adjustment to the conditionsof the classroom, but it can diverted too much from real life problems

• Solving a well known problem by the students also reduces and distorts theknowledge acquisition process, which is precisely the stage where a goodlearning is needed, since it is the bottleneck of the KBS developmentprocess.We have already advocated that the Case Study should come near real

world, but in a reduced size, with the objective of achieving a step by steptransition. After analyzing the different alternatives, the solution that is chosen,is the reduction of a real case, simulating some difficulties: the communicationwith the expert and the determination of the system scope. It is not a real case,but it is not invented and it presents the interaction difficulties with the expertWith the FP, the student takes a step towards the real KBS development.

The elected problem consists of developing a prototype of KBS for themotors diagnosis. The teachers and their group developed a real KBS for thisdomain It is an easy topic to understanding, though it is not of general domain,to enhance the expert role. The scope of the KBS developed has been reducedin order to become a Case Study for teaching and not a real problem.

The work complexity can be described in the following terms: fourknowledge acquisition meetings; three types of techniques of the eight that arepresented in the Msc [7]; six concepts; six frame modeling, about sixtyproduction rules and some thousands of code lines.



3.4 Technology

The MSc is centered in the use of a KBS methodology used during years in thedevelopments of the Artificial Intelligence Lab. at UPM [7] (see Table 1). Thephases covered in the Case Study are: Application Identification, KnowledgeAcquisition, Conceptualization, Formalization, Implementation and Evaluation.

We have had special care in that the students are not faced alone to tasksthat they have not carry out before, without a guide or help. For example, theteacher explains the preparation and the analysis of the first acquisition meetingwith questions asked to the students. In the following lecture, the studentscollaboration is forced to be greater. In the remaining lectures the students, ingroups, prepare and analyze the meeting on their own. The same occurs withthe rest of the stages. After the teamwork, each group results are exposed andall the students together with the teacher try to agree on a solution for thestage. Figure 1 shows a teaching way chart. Once a solution for a given stage(for instance, conceptualization), this one is the input for all the groups to thenext stage (for instance, formalization). This agreement on the partial results ofthe development process is the only way to have under control the work of allthe groups, and to the teacher to know that the errors of a group belongs onlyto the stage they are working on, and not to previous stages.

Stage i-1

Stage

Grou

Gr

'

i3 1 works in t

^oup 1 stage re

Each groi

All toge

Teacher beginsf

his stage

jsults

|ap results are ex

tther agree on a s

the stage

iGroup n works in ti

^Group n stage rel

Dosed and discussed

olution to the stage

us stage

suits

Stage i+l

Figure 1: Teaching way for each development stage.

For this Case Study, the tool Kappa was chosen because:»It is available for the course.»The implementation can be fast due to the visual programming resourcesand the pre-programming mechanisms that it offers.

»Its features and simplicity allow for the concentration in the problem in ashort period of learning.



3.5 Social dimension

In the Case Study the social dimension is reduced to the students and thelecturer. This reduction provokes the loss of an important and complex elementof the systems development reality: the interaction with directors, users andexperts. But obtaining that interaction is not the objective of the Case Study,neither it is possible by time reasons. The students are organized in workingparties as in the preceding experience. This time, all of them take part in all theactivities, to diversify the students abilities [9]. In those working parties thestudents will accomplish the tasks of the knowledge engineer discussingbetween them which is the better solution.

The teamwork, in addition to be a mean of learning, forms part of thecontent that students must learn. It is fundamental that the students acquirecommunication abilities for this kind of work.

The lecturer has to assume several roles. Sometimes she/he has to act onlyas a teacher, explaining how to accomplish some tasks or why certain decisionshave been taken. Other times he/she has to play the role of an expert trying tosimulate an acquisition meeting. During the discussions, he/she has to act asmoderator and advisor.

4. Results analysis

As opposed to other areas where exist many objective measures with which tocharacterize a result, in the education is very difficult to find them. Differentpoints of view and critiques of some researchers to other abound. Shulman says[18]: "it is very possible that for the social sciences and the education divergentschools of thought coexistence will be a quite mature and natural state".

Yellen and Sanford use some "measurements" to describe their results [20].Those "measurements" have been used in the Case Study with the these results:• The students demonstrate an increase in the enthusiasm for their work in thecourse with the following facts:-The students participation increased from the first to the last day.-At the end of class they spoke with the teacher to deepen some topics.-The assistance to class was uniform. The students that attended the firstday, they keep attending it until the last.

• The students progress in the form of solving the situations.-In the first acquisition meetings they were not capable of taking a stepunaided. According they advanced, they knew the following step.

-The same occurred with the conceptual model reviews.-At the beginning of formal modeling they were not able to organize theconcepts and the rules with frames and production rules. After an examplewith a frame they continued on their own with the formal model.

• The effort required to get an acceptable system is reduced.-Progressive increase of the skill to be faced with whole problem at thesame time. At the beginning they had a "muddle" to organize the workThis "muddle" was removed step by step.



But these "measurements" only reflect the side of the lecturer. A survey wasprepared to study the students satisfaction with the Case Study.

The students answers showed a high satisfaction degree because: 1) theyconsider the Case Study has helped much in the comprehension of themethodology stages; 2) they believe the Case Study will help them to approachthe FP; 3) their affirmative responses on the importance of the Case Study; 4)they only suggest improvements in the aspect of duration of the subject and 5)nearly all of them agree with the form of developing the subject.

The students estimate that the Case Study contributes to their training intwo principal aspects: the integrated vision of the KBS development processand the transition from the theory to practice. The goals achievement of thesubject Case Study is observed, at least, in the beginning of the strategiclearning and the reinforcement of the tactical learning.

5. Conclusions

This Case Study approach has been put in practice during three courses and theresults have been satisfactory. It has improved the attitude and the aptitude ofthe students toward the development of a KBS, preparing them gradually forthe FP. Furthermore, the satisfaction of the students has reached a high levelSummarizing in a few words, it is worthwhile to carry on like that.

KEY WORDS: knowledge based system, teaching, learning, Case Study.

6. References

[1] Alonso, F; Juristo, N.; Mate, J.L y Pazos, J. Software Engineering andKnowledge Engineering: Towards a Common Life Cicle, Journal ofSystems and Software, 1996, 33, pp. 65-79.

[2] Anderson, J.R. Cognitive Psychology and Its Implications, Third Edition,W.H. Freeman and Company, New York, 1990.

[3] Clancy, M.J.; Linn, M.C. Case Studies in the Classroom, in ACMSIGSCE'92, pp. 220-223, 7%e faperj of fAg A fy-fAree 67(306%Symposium on Computer Education, Kansas City, MO, USA, March1992, ACM, USA

[4] Davis, A. 201 Principles of Software Engineering, Ed McGraw-Hill, 199 5.[5] Sabin, RE; Sabin, E.P. Collaborative Learning in an Introductory

Computer Science Course, in ACM SIGSCE'94 (ed Daniel Joyce), pp.304-308, The Papers of the twenty-five SIGCSE Symposium on ComputerEducation, Phoenix, Arizona, USA, March 1994, ACM, USA

[6] Fenstermacher, G.D. Tres aspectos de la filosofia de la investigacion sobrela ensenanza, Capitulo III, La investigacion de la ensenanza I. Enfoques,teorias y metodos, ed M.C. Wittrock, pp. 150-179, Paidos Educador,Barcelona, 1989.

[7] Gomez, A., Juristo, N. y Pazos, J Ingenieria del conocimiento:Construccion de sistemas expertos, Ed Ceura, Madrid. 1997.



[8] Ingargiola, G. et al. A Repository that Supports Teaching and Cooperationin the Introductory AI Course, in ACM SIGSCE'94 (ed Daniel Joyce), pp.36-40, The Papers of the twenty-five SIGCSE Symposium on ComputerEducation, Phoenix, Arizona, USA, March 1994, ACM, USA.

[9] Kanabar, V. Introducing Knowledge-Based Projects in a SystemDevelopment Course, in ACM SIGSCE'88, pp. 114-118, The Papers ofthe nineteenth SIGCSE Symposium on Computer Education, USA, 1988.

[10]Luker, P. & Rothermel, D The Philosophy of Artificial Intelligence: ageneral studies course with particular benefits to computer science majors,in ACM SIGSCE'94 (ed Daniel Joyce), pp. 41-45, The Papers of thetwenty-five SIGCSE Symposium on Computer Education, Phoenix,Arizona, USA, March 1994, ACM, USA.

[ll]Magno, D. A New Approach to Computer Science in The CommunityCollege: Negociated Teaching and Learning, ACM SIGSCE Bulletin, June1994, 26:2, pp. 47-51,60.

[12]Papert, S. La mdquina de losninos, Ed. Paidos, Barcelona, 1995[13]Pazos, J et al. La industria del conocimiento: un futuro inexorable,

ICADE, 1990, 21, pp. 21-48.[14][Pazos 93] Pazos, J.; Juristo N. y Gomez, A. Formation en ingenieria

informatica: Master en Ingenieria del Software y Master en Ingenieria delConocimiento, in TECNIMAP'93, pp. 389-394, /// Jornadas sobretecnologias de la informacion para la modernizacion de lasadministraciones piiblicas. Granada, Spain, Mayo 1993.

[15]Pilgrim, R A TIC-TAC-TOE: Introducing Expert Systems to MiddleSchool Students, in ACM SIGSCE'95 (ed Curt M. White), pp. 340-344,The Papers of the twenty-six SIGCSE Symposium on ComputerEducation, Nashville, TN, USA, March 1995, ACM, USA

[ 16] Sagheb-Tehrani, M. The technology of Expert Systems: Some SocialImpacts, Computers&Society, July 1993, 23:1-2, pp. 15-20.

[17]Sharma, R. S.& Conrath, D.W. Evaluating expert systems: the socio-technical dimentions of quality, Expert Systems, 1992, 9:3, pp. 125-138.

[18]Shulman, L.S. Paradigmas y programas de investigacion de la ensenanza:una perspectiva contemporanea, Capitulo I, La investigacion de laensenanza I. Enfoques, teorias y metodos, ed M C. Wittrock, pp. 9-94,Paidos Educador, Barcelona, 1989.

[19]Wolf W. & Rozansky, E Expert Systems: An Applied Course, ACMSIGSCE Bulletin, December 1990, 22:4, pp. 23-24,28.

[20]Yellen, RE and Sanford C C A Practical Systems Development Project:On the Transition Path from Fantasy to Realism, Computer Education,June 1992, n° 71, pp. 17-23.

[21] Yue, K. Using The Game Cube-4 as Example in an Introductory ArtificialIntelligence Course, ACM SIGSCE Bulletin, 1989, 21:3, pp. 8-10.

[22]Yue, K. Teaching a Graduate Expert Systems Course, ACM SIGSCEBulletin, December 1990, 22:4, pp. 49-64.


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