Computer aided instruction systems for plant operators

Int . J . Human – Computer Studies (1996) 45 , 397 – 412

Computer aided instruction systems for plant operators

H IROSHI U JITA

Power & Industrial Systems R & D Di y ision , Hitachi , Ltd . , Omika 7 - 2 - 1 , Hitachi , Ibaraki , 3 1 9 - 1 2 Japan , email : ujita ê nupec .jcn .nihon - u .ac .jp

T AKESHI Y OKOTA

Hitachi Research Laboratory , Hitachi , Ltd . , Omika 7 - 1 - 1 , Hitachi , Ibaraki , 3 1 9 - 1 2 , Japan

N AOSHI T ANIKAWA

Hitachi Works , Hitachi , Ltd . , Saiwai 3 - 1 - 1 , Hitachi , Ibaraki , 3 1 7 , Japan

K EIKO M UTOH

Nuclear Power Research and De y elopment Centre , Tokyo Electric Power Company , Japan

( Recei y ed 1 4 March 1 9 9 5 and accepted in re y ised form 1 6 May 1 9 9 6 )

Two types of CAI systems have been developed which make it possible to provide consistent education in plant operation for personnel from novice to expert levels and on to professionals like shift supervisors . The main features are summarized as follows . (1) Realization of an attractive feature , representing the fusion of education and amusement . A two layer structure was adopted , so operators can get systematic knowledge spontaneously , while enjoying the task . In the lower layer which is hidden from the operators , an education scenario was created to provide overall knowledge for the plant operators , such as system configurations and functions , and normal and emergency operation procedures . In the upper layer which is shown to operators , an attractive story with a game feeling was constructed corresponding to the education scenario . (2) Satisfaction of intrinsic motivation , representing instruction according to the learners’ level . The student model is derived from a hierarchical function model which is a goal-oriented mental model of a plant operator . It is common to both the teaching course for presenting text knowledge of emergency procedures and the indicating course for actual plant behaviour and procedures using the plant simulator . The understanding level of each node (element of a function) in the model is evaluated by personal history conditions calculated from both the tutoring record of the node and the understanding level of the connecting nodes . ÷ 1996 Academic Press Limited

1 . Introduction

Recently , computer assisted instruction (CAI) systems have come into broad use in of fices , schools , and elsewhere , because of their ef fectiveness in facilitating self-

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H . UJITA ET AL . 398

study . Such systems have also been developed for and introduced into nuclear power plants so that operators can study system configurations and functions , operating procedures , etc . However , most systems place the emphasis on developing the systems’ function to indicate knowledge materials ef fectively , and therefore they have not been used as frequently as they should be by the users .

The authors have started to construct an education system with a new concept which extracts intrinsically motivations from operators ef fectively , in particular arouses instinct of ‘‘challenge’’ (Malone , 1981) and ‘‘confidence’’ in ARCS model (Keller & Suzuki , 1988) . This approach is optimal because operators have desires to improve their abilities as professionals (Maslow , 1954) . Plant behaviour is the most important item for operators who need to understand plant operations , therefore multi-media and simulation techniques have been used . Good educational materials have been gathered from safety analysis reports , operational procedures , etc . In addition to these , basic CAI functions , such as good interface and mutual understanding , have been prepared .

There is a large volume of varied knowledge to be presented to and learned by operators who have also a wide range of education levels and experiences from novice through expert and on to professionals like shift supervisors (Dreyfus & Dreyfus , 1986) . The ideal system would provide instructions for all the knowledge and cover the entire spectrum of operator types , but such a system is impossible to make . The strategy planned for the development of our two systems are as follows . One system gives instruction in basic but overall plant knowledge from novice operator to expert levels (Kubota et al . , 1993) . The system was developed by pinpointing attractiveness and fixed courseware because targeted personnel include novice operators , and was called Attractive CAI system . The second system gives instruction in emergency procedures for professionals such as shift supervisors or safety engineers (Yokota , Ujita , Kato , Tanikawa & Sida , 1992 ; Yokota , Ujita , Kato & Tanikawa , 1993) . The procedures were newly revised by operational professionals to provide a symptom-based response to accident situations based on the usual event-based procedures (Minsky , 1986) . The intelligent CAI system pinpoints intellectual ambition or ‘‘cognitive curiosity’’ based on comprehension of the understanding level because the target is professionals (Malone , 1981) .

Both systems try to extract intrinsically motivation in dif ferent ways . The Attractive CAI system adopts ‘‘educational simulation techniques’’ (Baba , Uchida & Sawaragi , 1984) to give ‘‘fantasy’’ (Malone , 1981) , ‘‘attention and satisfaction’’ (Keller & Suzuki , 1988) , and ‘‘constructivism (Papert , 1980) , which extracts motivation charmed by the attractiveness of the game (Yamamoto , 1988) . The Intelligent CAI system adopts the concepts of cognitive curiosity (Malone , 1981) , ‘‘relevance’’ (Keller & Suzuki , 1988) , and ‘‘instruction for comprehension’’ (Hatano , 1995) , and uses a hierarchical function model (Rasmussen , 1983) , which is a goal-oriented mental model of a plant operator , modified by the authors from emergency procedures . Novice operators would use the Attractive CAI system at first , and are expected to improve their knowledge and skills to the level of experts or professionals and increase their cognitive curiosity and relevance . Therefore the Intelligent CAI system will be used according to their understanding levels .

F IGURE 1 . Photo of the attractive CAI system .

COMPUTER AIDED INSTRUCTION SYSTEMS 399

2 . Attractive CAI for overall plant knowledge

2 . 1 . DEFINITION OF ATTRACTIVE CAI

Conventional designs of CAI systems focus on ef ficiency of the learning process and thus do not consider users’ motivation to use them . In contrast , computer games are widely distributed and played all over the world . Their players are deeply involved due to the motivation charmed by the attractiveness of the game (Yamamoto , 1988) . Based on their popularity , the Attractive CAI system has been developed as a joint research project carried out by Tokyo Electric Power Company and Hitachi , Ltd . (Kubota et al . , 1993) . The system is constructed on a personal computer for easy use as shown in Figure 1 .

The system fuses games and an educational system as shown in Figure 2 . It mainly adopts the attractive function of the role-playing game in which the user assumes a hero identity and makes some conquest in the virtual world . In addition to this , intellectual attractiveness through quiz game or puzzle game formats , competitive awareness by the comparison of other users’ results through score table , and a feeling of being in the virtual world through the simulation game format are considered . The most important point in developing the system was that knowledge required for the operator in a nuclear power plant should be studied in a sequential way , such as system configurations and functions as the first step , then normal operation procedure , and moving on to plant behaviours and response procedures

Game

Role-playing game

Quiz game

Puzzle game

Simulation game

Education scenariofusing to game story

Parts gathering

Recovering parts from enemies

Construction & generation

Construction of plant usingparts

Commercial operation

Operation in place

Incident managementResponse to incidentcaused by enemies

Education

Process increasing plant knowledge

Systemconfigurations

Systemfunctions

Normal operationprocedures

Incident operationprocedures

Plant behaviours

F IGURE 2 . Fusion of game story and education scenario focusing on the plant operation process .


in accident situations as final step . Therefore , a two layer structure was adopted , so operators can get systematic knowledge spontaneously while enjoying the task . At the lower layer which is hidden from the operators , the education scenario , which is the same as conventional course ware , was created to give instruction in overall knowledge for plant operators , such as system configurations and functions , and then normal and emergency operation procedures . In the upper layer which is shown to operators , an attractive story in the virtual world , which is similar in appearance to role-playing game story , was developed according to the education sequence of the plant knowledge .

The system has two additional functions based on the above-mentioned function . One is to indicate plant overall knowledge . Thus , if the operator does not want to challenge the game or just wants to acquire knowledge quickly , he or she can use the system as an electric manual . The other is a competitive one in which operators answer questions about a certain system knowledge and compare their results through score table with each other .

2 . 2 . EDUCATION PROCEDURE

The system configuration is composed of two memories , one for education knowledge and the other for the education scenario corresponding to the knowledge . The process unit guides the learners at their respective levels using the education scenario , and it also controls the input and output devices (Figure 3) . The knowledge for plant operation is arranged and systematized according to education contents and sequence , and fused with the interesting story line .

The story which adopts attractiveness by employing various types of game is as follows . An evil organization takes control of the plant and cuts of f all electricity

Memory foreducation knowledge

Memory foreducation scenario Process unit

Systemconfigurationsand functions

Normaloperationprocedures

Incidentoperationprocedures

Overall scenario

Scenario"construction &generation"

Scenario"commercialoperation"

Scenario"incidentmanagement"

Educationfunction

I/Ofunction

Errorjudgementfunction

Display

Speaker

Keyboard

Mouse

Simulator

F IGURE 3 . System configuration of attractive CAI system .


Object of education(Type of knowledge)

System configurationsand functions

"Construction & generation" "Commercial operation" "Incident management" Tests of 1-4

1 Normal operations2 Incident operations3 Final evaluation4

Functions Configurations

Form of knowledge Completion of flowchart Final test

Response in simulation GraduationParts gathering Construction

Completion ofsystem table

Completion of overallconfiguration

Completion of flowchart

F IGURE 4 . Learning flow . 1 – 4 : Education sequence ; ‘‘ ’’ : contents of questions in fighting scene .

supplies . The hero then constructs a new plant or restarts the old one and recovers electricity by fighting the evil organization . In the story (or scenario) , there are four types of scene , as shown in Figure 4 (and also Figure 2) , parts gathering , construction and generation , commercial operation , and incident management , each of which corresponds to a group of education materials . The education content level progresses from knowledge of each system to knowledge of the plant overall . Step 4 makes the final evaluation through accident simulation game to judge whether the learner’s level is enough to graduate from the education course or not . Figure 5 shows a map of the virtual world in the scenario . Each step corresponds to a dif ferent place or a dif ferent story . STEP 1 (Knowledge of system configurations and functions) : the hero / operator goes to a sanctuary of knowledge , where operator can get knowledge about a plant system , occupied by the enemies who have robbed system parts from a plant . He answers the quiz about the system configurations and functions in the fighting scene . He must collect parts in eight sanctuaries of knowledge which correspond to the main systems . Then he constructs the plant using the parts . When the electricity supply is restarted , the hero moves to another island . STEP 2 ( Normal operation procedures for each system) : the hero goes from plant to plant , answers the quiz about normal operation for each system , and restarts each plant for commercial operation . STEP 3 (Incident operation procedure) : the hero goes to a plant which he had previously restarted , but which has experienced some kind of incident introduced by the enemies . He answers the quiz about event-based procedure for the incident and eradicates the incident . STEP 4 (Overall plant knowledge , especially plant behaviours and responses) : the hero goes to a tower and fights with the leader of the enemies by answering the quiz


about plant accident situations , using the plant simulator . Finally , he releases the virtual world from the enemies’ control .

Figures 6 and 7 show examples of questions in fighting scenes , yes – no type and puzzle type encountered in STEP 1 .

The system prohibits a user from proceeding to the next step until the present step is cleared . Therefore the user has a feeling of free movement in the virtual world , while being required by the system to attain the knowledge systematically . Basically , the system adopts a role-playing game concept in which a user does not receive correct answer or advice if he or she answers incorrectly , that is , only intrinsic feedback is given . However , from the educational point of view , a lecture function is added . Users can obtain graphical and vocal representations of the system configuration and function or operational procedure by going into school in town before entering a fighting scene . Therefore if users want to obtain good results , they must study hard using the lecture function , electric manuals , or text materials beforehand . Users understand their levels by the step they reach and points they earn , that is , the system gives some kind of extrinsic feedback upon user contact .

2 . 3 . VERIFICATION OF THE SYSTEM

Two sets of the systems were placed in the operators’ waiting rooms in two types of control rooms for about 2 months , during which time they were used and evaluated by operators . Two types of knowledge were prepared according to the plant type and control room type dif ferences . Subsequently , interviews of the two crews representing the two types of plants were carried out regarding acceptance of the system concept of attractiveness and its functions . The system concept and four-step story were favourably accepted by operators , with some suggestions for functional revisions . Main points are as follows . (1) The knowledge for plant operation had been systematically arranged according to the education level from a system configuration to an incident operation procedure . However , operators claimed that , there are levels of dif ficulties even for the knowledge of a system configuration itself . Therefore , knowledge and questions in each STEP were divided into two levels of dif ficulty corresponding to operators’ knowledge levels . (2) In the fighting scenes , the correct answers had not been indicated to the user (intrinsic feedback is given) , because the system adopted the concept of a role-playing game . However , operators claimed that if answers were not known or were wrong , the correct answers should be shown for good understanding . As a compromise , a help function (extrinsic feedback) was adopted which gives hints indirectly when requested , by applying lecture function (Figure 8) .

3 . Intelligent CAI system for emergency procedure

3 . 1 . EMERGENCY PROCEDURES AND EDUCATION METHOD

In order to perform appropriate operations during a severe condition , operators need both skill- and rule-based training and knowledge-based training . A full scope simulator has been used for skill- and rule-based training . But , knowledge-based training has been done by reading textbooks . The main objectives of the Intelligent CAI system developed in house at Hitachi , Ltd . are to provide operators with

F IGURE 5 . Map of virtual world .

F IGURE 6 . Example of question (Yes – No type) in fighting scene .

STEP 1 "System configuration and functions" STEP 2"Normal operation"

STEP 3"Incident operation"

STEP 4"Final evaluation"

Question Name and power of enemy Image of enemy

Image of player

Icon to use tools Name and power of playerAnswer selectionto question

F IGURE 7 . Example of question (puzzle type) by which a plant is constructed using parts recovered from enemies .

F IGURE 9 . Photo of the intelligent CAI system .

System configuration area

Messagearea

Partsgatheredarea

Construction parts area


* * * * * * * * * * * * * * * ** * * *

1 * * * * * 2 * * * * * 3 * *

Next question

HELP

Return toquestion Wrong answer

"HELP"selected

Wrong!

Lecture"Lecture"not-selected

"Lecture selected"

"Lecture" for help

When "Lecture" selectedWhen "HELP"selected

F IGURE 8 . HELP function to indicate correct answers to questions .

knowledge of emergency procedures and also plant behaviour (Yokota et al . , 1992 , 1993) .

Figure 9 shows a photo of the Intelligent CAI system . Two engineering work stations are used ; the education function is installed in one station and the plant simulator is installed in the other . The system configuration is the same as in a conventional Intelligent CAI system except it is attached to a simulator which assists in creating plant behaviours and actual procedures to respond to the behaviours as shown in Figure 10 .

The system is designed with four study steps (Figures 10 & 11) so that learner – users can study the emergency procedures step-by-step from an elementary level to their application level . First , the general concepts of plant safety and emergency procedures are explained . Second , the technical background and contents of the emergency procedures are explained , and the understanding level is confirmed in a Question & Answer style study . Third , real-time simulation is executed for a certain accident scenario to show the behaviour of the main plant


Plant characteristics Textknowledge(ideal model)

Student model(hierarchicalfunction model)

Procedures etc.

Tutoringstrategyfunction

Textknowledgeinstructionfunction

Operationprocedures· concept· content

Plantsimulator

· Instruction simulation

·Free simulation

Student Human interface

Plantstate Operation

Recommendedcourse

Course request

Answerquestion

Materialindicationquestion

Instruction Instruction

Text knowledge Text knowledge

Operation results Learning results

Understandinglevel

F IGURE 10 . System configuration of intelligent CAI system .

Understandinglevelevaluation

Operation procedure concept

Operation procedure content

Introduction simulation

Free simulation

Model usedfor eachstep

Cold shutdown

Reactor integrity

maintaining

Containmentintegrity

maintaining

Reactivitycontrol

Reactor levelcontrol

Level recoveryLevel

maintaining

***

**Normal sys. High pressure

sys.

*

Level

Operationgoal

Plant

System

Sub-system

Component

(1) Tutoring strategy(2) Ideal model (hierarchical function model)

(3) Student model (understanding level)

Numbers of errors

Numbers of trials

5/35Accepted

5/12 0/10

3/10 2/15

Level maintaining

Normal sys.**

***

Level recovery

Normal sys.OK?

No

YesDetailedfunction

(4) Operation procedure

F IGURE 11 . Tutoring strategy and student model .


parameters . Operation of main plant components and devices (e . g . valves) can be performed by answering questions which are asked from the system according to the plant status , and the understanding level is also confirmed . Learner – users can achieve the ideal operation as a result . In the fourth step as final , students can use any scenario and achieve the operation by themselves . In the step , the understanding level is not estimated , because of dif ficulty in evaluating operator performance . However , they can compare the change of parameters from their own operation with the ideal one , and can recognize the necessity of the operation quantitatively (amount , timing , etc . ) . Through the above steps , learner – users come to understand the technical background of the emergency procedures and the behaviour of the main plant parameters .

3 . 2 . INTELLIGENT TUTORING FUNCTION

The system is designed to satisfy the following four tutoring functions .

(a) Individual tutoring adaptive to student understanding conditions . (b) Conversation between students and the system by mutual initiative . (c) Harmonization of knowledge of procedures to that of plant behaviour . (d) Promotion of a goal-oriented policy to respond to plant symptoms .

The first two functions are characteristics of an intelligent tutoring method , and the latter two are requirements for education in emergency operation procedures . The student model and tutoring strategy using it have been proposed to realize these functions as shown in Figure 11 .

Main characteristics of the system are as follows .

(1) The system has two types of broad tutoring course : teaching text knowledge by using a Question & Answer style (first and second steps) , and teaching actual procedures and process behaviour by using a simulator (third and fourth steps) . The tutoring strategy selects the appropriate step from among the four and instructs operators according to their understanding levels as evaluated from the individual’s education history and error content in the student model , which is common to both courses . (2) The student model is combined with a hierarchical function model , which is considered as a goal-oriented mental model of the plant operators (Rasmussen , 1983) , and the flow chart of operation procedures . The model is commonly used for each step . A detailed structure of the model is given in Figure 12 . It is defined as a combined structure of each node (element) of the hierarchical function model and each node of the detailed operational procedure via a function concept node , and the educational history and understanding level are assigned on each element of the structure . The study area (node) corresponding to the procedures and its understanding level are always indicated to the learner – users on the hierarchical function model . (3) The understanding level of each node (element) is evaluated from personal history conditions calculated from both the tutoring record of the node , which is composed of the number of correct answers with weight having been giving to the newest records and the newest error type , and the understanding levels of the


Student model Hierarchical function model

Reactor integrity maintainingNode

Coolant maintainingAbstractfunctions

Detailedfunctions

Systemsused

Reactor pressure control

Water levelmaintaining

Contingentoperation

Depressurizationcooling

Coolant injection sys. Depressurization sys.

Function concept

Procedure flow

Physicalcharacteristics

Start conditions

Purpose

Meaning

Emergency procedure

No. 1 Start conditions

No. 2

No. 3

No. 8

Operation guideof depressurizationguide

Reactordepressurizationoperation

Depressurizationwithsafety relief valve

Recorded data (recorded on every node.)

· Personal history of study: number of correct answers, error type

·Understanding level of node:

Level = Personal history condition coefficient+Personal history condition : calculated based on number of correct answers

Coefficient : given based on error type and understanding levels

of connecting nodes

· Careless mistake

· Misunderstanding of node connection

· Misunderstanding of start conditions

· Insufficient understanding of basic function concept

· Knowledge lacking

F IGURE 12 . Basic constitution of student model .

connecting nodes . The system automatically analyses and indicates error type , composed of error cause and error level , the latter indicating the magnitude of the error’s ef fect on the plant . As the system has been developed for professionals to study themselves , the possibility exists that enough personal history cannot be obtained , and some kind of countermeasures are required to comprehend the understanding level . Here , the authors adopted a method to apply connecting node information to evaluate certain node understanding level . If a correct answer was given to the node , the total value of 1 . 0 was divided among the node and its connecting nodes according to their connecting strength (de Kleer , 1986) . Further- more , the understanding level of each node is modified by the average value of connecting node understanding levels . This function helps students to recognize their understanding level and allows them to concentrate on weak points . (4) There are three types of feedback as follows .

(a) Feedback for each question . If a user answers incorrectly to the question by the system in operation procedure concept , operation procedure content , or instruction simulation course , the system indicates error cause and level , and also provided advice or hints .

(b) Feedback for overall course . The system supports the user in selecting the next learning course or learning area (plant system) . The understanding level distribution is represented using the hierarchical function model with personal history conditions and error type statistics for each node . The next learning course is determined by the understanding level distribution and error type statistics , and the recommended learning area is indicated as a group of low-score nodes of the model .

F IGURE 13 . CRT display indicating simulation situation .


(c) Course ware revision . Course ware is revised when an extreme unbalance is observed on average of understanding level distributions and error type statistics for all users .

3 . 3 . PLANT SIMULATOR

The simulator is used for the purpose of educating learner – users in emergency procedure operations . So , it is designed to be able to simulate plant situations , including accidents in which symptom-based plant operation is applied . The operation should be performed in real time , and the plant status should be indicated .

The simulator includes a detailed model of the reactor , primary containment vessel , safety systems and major control systems . By using a real-time simulator , users can operate the main plant components while experiencing the feeling of a real-time progression of the event . This gives students a sense of operation reality .

The main purpose of the system is to make the operators understand the importance of the emergency procedures implementation . Users are expected to know the usual event-based plant operation well , study the concept of emergency procedure , and understand plant behaviour in emergency situation perceptually by simulation . Therefore , a typical plant type is considered and modelled . Operations can be performed in this simulator , such as start-up of the standby liquid control system , protective action of the primary containment vessel to prevent a dif fused radioactivity release , and operations to keep the reactor water level at a certain level by using various plant systems which supply water . Details of operations which are not directly related to the emergency procedures , for example the line up of valves , do not need to be performed exactly . The education system was designed to allow operation of 22 plant systems from the menu for each system on the CRT .

In the actual plant , there are a lot of indicators , recorders , lamps and annunciators . But , it is impossible to show all of them on the two CRTs which are used in the system . Six indicators , 22 annunciators and a display of conditions for 30 plant components are used (Figure 13) . Other aspects of plant status are displayed on the same CRT in a text form . Displayed elements are changed according to the accident .

Trend graphs of the main plant parameters are indicated on one CRT , and the status of the main components and the annunciator are summarized on the other . All the statuses are renewed , in synchronization with the simulation . A colour indication method is widely used for quick grasping of the plant status . For example , streams of steam or water are expressed by changes of pipe colours , and when some parameters reach critical set points , the colour of the indicator is changed to attract the student’s attention to it . Indication methods mentioned above help the student to keep a high level of interest in the study .

3 . 4 . VERIFICATION OF THE SYSTEM

Functional evaluation of the student model and tutoring strategy (determination) function were done using seven subjects ; two novices , three experts , and two professionals . The subjects studied four main procedures each for one hour using a knowledge education course . The understanding levels , and recommended courses and areas were shown to them and they were interviewed afterwards .


Inegritymaintaining

(24)

(100)

A

C

Inventorymaintaining

(54)

(74)

Water levelmaintaining

(5)

(87)

Reactor pressurecontrol

(16)

(100)

Sub-criticalmaintaining

(87)

(85)

Unanticipatedoperation

(45)

(77)

Low pressurecooling

(44)

(100)

Reactivitycontrol

(50)

(28)

Control rodinsertion

(25)

Coolant supplysystem

(10)

(23)

Depressuriza-tion system

(57)

(100)

Residualheat removal

(7)

(97)

Stand-byliquid control

(54)

(40)

Scram

(7)

(24)

Understanding level

100–75 74–50 49–25 24–0

(25)

Instruction control

Course

A: Procedure conceptC: Similar to operation

Area

Water-level maintaining, scram, residual heat removalCoolant supply system, scram, control rod insertion

F IGURE 14 . Understanding levels of subjects A (novice) and C (expert) .

Two examples of the understanding levels , novice and expert , evaluated by this system are shown on the hierarchical function model in Figure 14 . The results for this novice show his understanding level was low (mean level 5 35) over all the functions . Even the high level points were confirmed by him as being random guesses . On the other hand , the expert’s results show a generally high understanding level (mean level 5 71) , being low in only sub-criticality functions . Component level understanding was a little bit low compared with the conceptual level . This was indicated in the interview as being due to an individual preference for studying general knowledge well , but not for learning detailed operational procedures .

Evaluation results indicated that the student model estimated students understanding levels correctly and the tutoring strategy (determination) function recommended proper courses and areas according to those levels .

The understanding level distribution on the hierarchical function model was evaluated as shown in Figure 15 . As the nodes connected by the arcs on the model have tight functional relationships to each other , little dif ference among nodes connected to each other means good (ideal) balance of the study situation (understanding level) . Therefore , the vertical axis indicates a summation of dif ferences of understanding level among nodes and the horizontal axis , a summation of understanding level of all nodes . The lower right-hand side represents the ideal understanding level . Generally speaking , understanding level points distributes from initial lower left (0 , 0) , increasing , decreasing , and then reaching the lower


Interpolation of correlation curve

Initial state

Correlation curve

Final goal

B A

C

FDE

G

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

Summation of understanding levels of nodes [–1] 100

7

6

5

4

3

2

1

0

Sum

mat

ion

of d

iffer

ence

of u

nder

stan

ding

leve

lsbe

twee

n no

des

[–1]

1

00

+

+ F IGURE 15 . Correlation curve of understanding level for seven subjects . A , B : Novice ; C , D , E : expert ; F ,

G : professional .

right of the final ideal understanding level (1400 , 0) . Each subject’s understanding level is distributed on the predicted curve form . It is clear from the graph that learner C understands each knowledge type well but such knowledge is not systematic compared with experts D and E .

The system was installed at the training center for trainee operators and is now being evaluated by training instructors .

4 . Discussion

Two of the most important features of a personal CAI system are its easy use and absence of user boredom while studying . The system utilizes an ef fective human – computer interface ; for example , it includes input only by a mouse , voice instructions , dynamic indications of plant status , and colourful displays on high resolution CRT . The system supports the human – computer interface functions mentioned below , in order to realize ef fective study .

(1) Compact size . Compact size is an important requirement for actual use of the system . This requirement is realized by applying a laptop / desktop personal computer or high performance engineering workstation . (2) Easy input to the system by a mouse . Students must input items to the system , such an answers to questions , selection of operation items , change in parameters of the trend graph , advancement of the study step and so on . All these can be input by using just the mouse . This makes quick response possible without special knowledge about the computer system operation .


T ABLE 1 Specifications of education systems

— Attractive CAI Intelligent CAI

Object Novice to expert Professional Content Plant overall knowledge Emergency procedures Type Portable set for operator crew System set at of fice in-site Hardware & software $ Laptop / desktop personal

computer $ Multimedia (voice , music , CG

etc . ) $ Simulation cases $ Education scenario fused with

game

$ Two graphic workstations

$ Voice instruction (large display)

$ Full-scope simulator $ Student model and tutoring

strategy

(3) Multi-media application . In order to improve attractiveness and education ef fectiveness for users , multimedia approaches are used , such as cartoons , computer graphics , drawings , films , voice instructions , music , sounds , etc .

Table 1 compares specifications of two education systems . The Attractive CAI system teaches overall plant knowledge to the operators for a wide range of personnel from novices to experts . This system was developed on laptop / desktop personnel computer for operator crew members to use any place and at any time with various multimedia . On the other hand , the Intelligent CAI system is targeted at professionals , like shift supervisors , to instruct them in emergency procedures . The system was developed on two graphic workstations with full scope simulator (and with large display) to be set in an of fice in-site . Both systems mutually cover the objects and contents , and therefore can teach every area of knowledge required for operators from novices to professionals .

Figure 16 shows all functions which should be attached to education systems . The centre part functions are derived from conventional CAI system requirement . The upper part functions are derived from educational simulation techniques (Baba , Uchida & Sawaragi , 1984) to give fantasy (Malone , 1981) and constructivism (Papert , 1980) , which extracts motivation charmed by the attractiveness of the game (Yamamoto , 1988) . The lower part functions are derived from the concepts of cognitive curiosity (Malone , 1981) and instruction for comprehension (Hatano , 1995) . Conventional CAI systems have one or two functions in the centre part , while usual intelligent CAI systems have three or four functions in the lower part . Two CAI systems developed in this study have some similar target functions such as ambition , good interface , and the conventional CAI function of mutual conversation and good education content . Both systems try to extract intrinsically motivation in dif ferent ways . They have some completely dif ferent concepts , such as the attractive one aims at the amusement function while the intelligent one , provides the instruction function based on the understanding level . Therefore the Intelligent CAI system has about ten functions in the lower part . On the other hand , the Attractive CAI system has tried to develop functions , about 10 of them , which satisfy the upper part , especially amusement functions . The two systems mutually cover the functions to be attached to the education system . Each system serves its intended


CAI extractingusers' motivation

AttractiveCAI

IntelligentCAI

Amusement

Ambition

Good interface

Conventionalfunction of CAI

Instruction due tounderstandinglevel

Comfort

Satisfaction

Attention

Suprise

Individuality

Easiness

Good educationcontent

Mutualconversation

Understandinglevel

comprehension

Entertainment

Voluntary

Intentioncomprehension

Story

Competition

Experience

Variation

Simple

Interactive

Education material

Cooperation

Student model

F IGURE 16 . Functions to be attached to education system .

purpose well . Therefore the complete education system which satisfies all the functions discussed here is highly beneficial for operator training .

5 . Conclusion

Two types of CAI systems have been developed which make it possible to provide education to personnel from novice operators through experts and on to professionals . Main features are summarized below .

(1) Pursuite of attractive feature (the fusion of education and amusement) . (a) The system target is to give instruction in basic but overall plant knowledge from novice operator to expert levels . A two layer structure was adopted , so the operator can get systematic knowledge spontaneously while enjoying the task . In the lower layer , which is hidden from operators , an education scenario was created to provide overall knowledge instructions for plant operators ; this includes system configurations and functions , and normal and emergency operation procedures . In the upper layer which is shown to operators , attractive story with game feeling was constructed corresponding to the education scenario . (b) Two sets of the developed Attractive CAI System were introduced to operators’ waiting rooms of dif ferent types of control room for 2 months for the system function evaluation . The system was favourably received by the operators . (2) Satisfaction of intrinsic motivation (instruction according to the learners level) . (a) The system target is to give instruction in emergency procedures which were newly edited as a symptom-based response to accident situations for professionals such as shift supervisors or safety engineers . The student model is derived from a


hierarchical function model which is a goal-oriented mental model of a plant operator , modified by the authors from emergency procedures . It is common to teaching course for presenting text knowledge of emergency procedures and the indicating course for actual plant behaviour and procedures using the plant simulator . The understanding level of each node (element of function) in the model is evaluated by personal history conditions calculated from both the tutoring record of the node and the understanding level of the connecting nodes . (b) The developed Intelligent CAI System was evaluated using seven learners of dif ferent understanding levels and it was confirmed that the system could success- fully determine and notify their understanding levels and recommend proper courses according to them .

The work to develop an attractive CAI System was done as a joint research project carried out by Tokyo Electric Power Company and Hitachi , Ltd . The Intelligent CAI System was developed in house at Hitachi , Ltd .

We would like to acknowledge Professors Ri-ichiro Mizoguchi of Osaka University , Setsuko Ohtsuki of Kyushu Institute of Technology , and Yoneo Yano of Tokushima University who provided invaluable advice on the concept of education systems . We also wish to thank the participants in the verification tests including personnel from the utility operators , the training instructors , and the vendor operators .

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Paper accepted for publication by Associate Editor , Professor P . Barker .

Documents

Computer aided instruction systems for plant operators