In supervisory control systems such as satellite ground control, there is a need for human-centered automation where the focus is to understand and enhance the human-system interaction experience in the complex task environment. Operator support in the form of off-line intelligent tutoring and on-line intelligent aiding is one approach towards this effort. The tutor/aid paradigm is proposed here as a design approach that integrates the two aspects of operator support in one system for technically oriented adults in complex domains. This paper also presents GT-VITA, a proof-of-concept graphical, interactive, intelligent tutoring system that is a first attempt to illustrate the tutoring aspect of the tutor/aid paradigm in the domain of satellite ground control. Evaluation on GT-VITA is conducted with NASA personnel with very positive results. GT-VITA is presented being fielded as it is at Goddard Space Flight Center

Chu, Rose W.

Mitchell, Christine M.

English

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ABSTRACT 
In supervisory control system such as satellite 
ground control, there is a need for human- 
cenfered aumation where the focus is to 
understand and enhance the human-system 
interaction experience in the complex task 
environment. Operator support in the form of 
offline intelligent tutoring and online intelligent 
aiding is one approach towards this effort. The 
tutor/aid paradigm is proposed here as an 
desing approach that integrates the two aspect 
of operator support in one system for technically 
oriented adults in complex domains. This paper 
also presents GT-VITA, a proof-ofconcept 
graphical, interactive intelligentutoring system 
that is a first attempt to illustrate the tutoring 
aspect of the tutor/aid paradigm.in the domain 
of satellite ground control. Evaluation on GT- 
VITA was conducted with NASA personnel 
with very positive results. GT-VITA is 
presented being fielded as it is at Goddard Space 
Flight Center. 
Keyword: Intelligent tutoring systems, operator 
support, technical training, supervisory control. 
1. INTRODUCTION 
In very highly automated systems such as 
satellite ground control and process control, the 
human operator is involved in supervisory 
control task - monitoring system states and 
compensating for system failures (Ref. 10, Ref. 
13). On one hand, advances in computer 
technology over the years had contributed to the 
efficiency and productivity of automated 
systems in terms of high-performance 
equipment and innovative automation control 
strategies/algorithm. On the other hand, it is 
clear that the operator's changing role in 
Altanta, GA 30332-205 
cm&hmsr.gateCh.edu 
(205) 894-4 
automation has also resulted in a new set of 
problems with prevailing 
and safety. This is evident in tragedies such as 
the three-mile island accident. Consequently, 
there is a need for human-centered aumation 
where the focus is to explore technology not just 
for better automation, but for understanding 
and enhancing the human-system interaction 
experience in the complex task environment 
resulted from automation. 
To reduce task complexity, Leplat (Ref. 8) 
suggests either changing the operator through 
training or changing the task through redesign. 
At NASA Goddard Space Flight Center, existing 
training methods to prepare novice for satellite 
ground control at the Mission Operations 
Division include classroom instruction, quizzes, 
volumes of reading materials, and on-the-job 
training. Unfortunately these methods are 
inadequate by themselves in meeting new 
training requirements imposed by the nature of 
supervisory control task and the complexity of 
the task domain. Operators require high-level 
skills beyond rote memory of procedures and 
rules to manage trouble when trouble arises, and 
to copy with unanticipated variabilities in 
system behavior. In addition, for on-the-job 
training, there is the problem of knowledge 
attrition that results as new generations of 
operators are being trained over time. 
Hence the primary motivation for the research 
work reported in this paper is to explore the 
design of an intelligent tutoring system (ITS) for 
training novice operators in satellite ground 
control. 
For the next generation of mission control 
systems, researchers and engineers at Goddard 
are involved in changing aspects of the satellite 
** This work was completed in 9ptember 91 as part of Rose Chu's doctoral program at Georgia Tech . 
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https://ntrs.nasa.gov/search.jsp?R=19940019456 2020-06-16T15:34:40+00:00Z
supeMsory control 
been in place for many years are often not 
amenable to redesign except potentially through 
distributed operator support tools and aiding 
systems. 
Hence, the research presented here also suggests 
a design paradigm that considers intelligent 
training and aiding as two ends in the spectrum 
of operator support. 
2. THE TUTOR/AID PARADIGM 
Conventionally, research in training has been 
fielded separately from research in aiding. We 
propose the tutor/aid paradigm in which an 
intelligent tutoring system (ITS) evolves from a 
tutor to an operator's assistant as the novice 
operator's expertise increases. The tutor/aid 
paradigm integrates the issues of computer- 
based training and real-time aiding in complex 
dynamic systems. We believe that a system 
developed to function both as a tutor and an aid 
is more cost-effective over time, and is more 
motivating for operators to learn, to use and to 
trust. The goal is to design a tutor that not only 
compensates for a novice operator's deficiencies 
in knowledge and skills, but also prepares the 
operator to use the tutor as an assistant after 
training. 
The tutor/aid paradigm proposes characteristics 
of an integrated intelligent tutoring and aiding 
system. The heart of which is a pedagogy 
structure that address "how and when and 
what" to teach to the novice operator of 
complex systems that eventually uses the tutor 
as an aid. Before the theory of the tutor/aid 
paradigm was defined, we investigated the 
recent developments in the field of intelligent 
tutoring systems. While research in intelligent 
aiding in complex domains has been emerging 
recent years. The distinction between academic 
ITSs and technical training ITss is crucial 
because methods and concepts that work in 
academic tutors may or may not work in 
technical tutors because of the nature of the 
target domain and the target student that each 
class of tutors is generally designed for. 
Consider the world of algebra and the world of 
steam propulsion plants. A tutor preparing a 
student for the former is very different from one 
for the latter due to the difference in knowledge 
and skills requirements imposed by the domain. 
From the vantage point of an individual 
performing some tasks in a world, a steam 
propulsion plant is more complex than algebra 
in dimensions of dynamism, the number and 
extensiveness of interacting parts, uncertainty 
and risk (Ref. 14). 
Academic tutors differ from training tutors not 
only in "what to teach", but also in "who" they 
are teaching. In industry, novice operators who 
are mature and technically oriented adults are 
highly motivated to learn and be trained 
specifically because of their vested 
performance, and in most cases, because their 
job mandates them to do so. In contrast, 
whether the students are first-graders or college 
freshmen, in an academic environment, students 
often learn for the sake of learning and in 
preparation for future vocations. Thus, at the 
time, they usually do not have a job at stake. 
2.2 Dimensions of an ITS 
From a design perspective, an ITS can be 
addressed from three aspects: communication, 
instruction and knowledge (Ref. 1). The 
communication dimension concerns the 
"interactivity" between the student and the tutor 
via the interface. The interactivity of recent 
646 
imparted. Of the three, the instructional 
dimension is the most difficult and least 
developed. Most ITSs to date embody some 
pedagogical philosophy but lack a structure that 
explicitly encodes the teaching knowledge. In 
addition, many student models to date are 
simply good recordkeeping of student actions. 
The knowledge dimension concerns the 
representation and presentation of the target 
domain. This dimension is probably the most 
developed, benefiting from the research and 
experiences in artificial intelligence. 
The representation issue is especially critical in 
knowledge-rich domains, where the tutor teaches 
the conscious and accurate use of knowledge in 
a high-level problem solving task such as 
electronic troubleshooting (Ref. 4). Whereas in 
high-performance domains such as air intercept 
control, the focus is on speed and automaticity: 
the tutor trains a student to perform some skills 
as effortIessly and reliably as possible (Ref. 4, 
Ref. 11). Most ITS research to date has 
emphasized knowledgerich domains or 
knowledge-rich components of the domain such 
as troubleshooting and fault diagnosis. 
2.3 Scope of the Tutor/Aid Paradigm 
In summary, based on the survey and analysis 
on current developments in ITS, the tutor/aid 
paradigm is an attempt to address some 
research needs in the field. First, the current 
work emphasizes the design of an ITS for 
technically-oriented adults in a complex and 
dynamic environment. Second, the focus is not 
just on training some knowledge component 
aspect of the task, but on training for the 
successful operations of supervisory control 
activities in realistic, time-constraint scenarios. 
Third, the tutor/aid paradigm proposes a 
pedagogy structure that explicitly defines the 
training process of the integrated tutor and aid. 
Fourth, instead of designing an 1Ts from scratch, 
the tutor/aid paradigm capitalizes on the 
ator's associate 
training state towards which a novice operator 
should be trained. 
The di S 
GT-VITA (Georgia Tech-Visual Inspectable 
Tutor and Assistant), a proof-of-concept ITS that 
is an initial attempt to illustrate and validate the 
tutoring aspect of the tutor/aid paradigm. 
Details of the tutor/aid paradigm can be found 
in Ref. 3. The aiding aspect of the paradigm is 
beyond the scope of this research but is 
addressed and complimented by a companion 
project on cooperative problem solving (Ref. 6). 
3. FROM GT-POCC To GT-VITA 
The GT-VITA project can be viewed as a direct 
response to the training needs and problems of 
existing systems at the Mission Operations 
Division of GSFC. 
A necessary first step of the project is to conduct 
extensive analysis on the NASA data- 
information system and the operator's 
knowledge and task requirements within the 
Payload Operations Control Center (POCC) 
Based on this analysis, we developed an 
interactive, real time simulation system called 
GT-POCC (Georgia Tech-POCC, Ref. 2). 
3.1 GT-VITA Interface 
GT-POCC provides the simulated task 
environment upon which GT-VITA is built up. 
GT-VITA is a graphical, interactive, real-time 
intelligent tutoring system. GT-VITA provides a 
graphical and animated representation of the 
NASA data-information system that allows a 
student to visualize system components, 
behavior and their relations at a various level of 
details. The graphical interface was developed 
in direct response to some concerns that were 
identified in o w  knowledge analysis. Operators 
at the POCC do not have a broad, top-down 
perspective of the NASA system (Ref. 7). Such a 
perspective has been argued to be cruaal for 
647 
as support for real-time operations after 
training, as illustrated in the companion project 
GT-MOCA (Georgia Tech-Missions Operations 
Cooperative Assistant, Ref. 6). Figure 1 is the 
NASA system graphic display, one of m y  
used both for GT-VITA and GT-MOCA. 
GT-POCC and GT-VITA have been 
implemented in C++ on Sun SparcStation 
platforms. The user interface have been created 
with Transportable Applications Environment 
Plus (TAE Plus, Ref. 121, an interface builder 
developed at GSFC. 
3.2 GT-VITA Tutoring Capabilities 
The tutoring capabilities of GT-VITA are 
captured in a pedagogy module that defines the 
instructional goals and strategies of the tutor in 
the form of eight lesson types. Figures 2 shows 
the pedagogy network as proposed by the 
tutor/aid paradigm. At present, GT-VITA 
implements seven of the eight lessons in three 
phases: declarative, procedural and practice. 
Right now, GT-VITA is not yet capable of the 
dynamic transition between lessons that the 
paradigm ultimately proposes. 
A typical training session in the GT-POCC 
domain is as follows: In the declarative phase of 
training, the student learns about the various 
NASA components such as spacecraft 
subsystems and ground computers, followed by 
the behavior of the NASA system in terms 
dynamic data flow between components. 
During this phase, the student also explores the 
NASA system both from the visual perspective 
as well as from the perspective of the tutor's 
internal hierarchical representation of the 
system. 
In the procedural phase, a student learns about 
the various satellite ground control activities 
first via tutor's demonstrations, followed by 
tutor's instruction to perform the activities. 
Finally, in the practice phase, a student has the 
opportunities to apply previous learned 
the second type of practice lesson, the tutor only 
intervenes during critical phases of the real-time 
ri0. 
4. GT-VITA EVALUATION AND RESULTS 
An evaluation of GT-VITA was conducted on 
site at GSFC, in June 1991. Sixteen NASA 
personnel volunteered six to nine hours of their 
time to participate in the evaluation. The 
subjects included software testing engineers, 
administrators, spacecraft specialists and 
computer operators. The subjects varied in their 
experience with computer technology (e.g., 
using the mouse). They also varied in their 
general knowledge of the NASA system and the 
duties of a POCC operator. However, none of 
the subjects had on-the-job experience as a 
MXC operator. All subjects were trained OII 
GT-VITA with all seven lessons The evaluation 
procedure consisted of subjective 
questionnaires, and obwtive performance 
measures. 
In general, results show that GT-VITA was 
perceived favorably by all the subjects in terms 
of what they learned. All subjects agreed that 
GT-VITA would be useful for training novice 
POCC operators. 
An analysis of the performance data collected 
for the practice lessons showed that regardless 
of the subjects' differing background, all subjects 
performed comparably and even committed 
consistent errors in the practice lessons. These 
results can be attributed to the flexibility and 
adaptability afforded by GT-VITA. 
Overall, the response of other NASA training 
personnel and managers have been very 
positive. Some have commented that GT-VITA 
could save them several months of training time. 
GT-WA is currently being fielded as it is at 
NASA, and also modified for the next 
generation T-POCC (Transportable POCQ 
applications. Eventually, the two different 
648 
In conclusion, the G 
first attempt 
issues in computer support systems for 
operators of complex dynamic systems. Many 
research avenues need to be conducted further 
to validate the full impact of the tutor/aid 
paradigm. The tutor/aid transition i s  being 
investigated at Georgia Tech. Other 
enhancements to GT-VrrA such as student 
modeling and curriculum transition are being 
explored at Honeywell. 
5. A C K N O W L E D G ~  
We gratefully acknowledge the assistance 
provided by the Mission Operations Division at 
NASA Goddard Space Flight Center, especially 
the NASA personnel who volunteered their time 
to participate in the evaluation of GT-VITA. 
This research was sponsored by NASA Goddard 
Space Flight Center under contract NAS5-28575 
(Walt Truszkowski, technical monitor). 
6. REFERENCES 
1. Burns, H. and Parlett, J.W. (1991). The 
evolution of intelligent tutoring s y s t a  
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systems: Emlution in design. Hillsdale, NJ: 
Lawrence Erlbaum Associates. 
2. Chu, R.W., Jones, P.M., and Mitchell, C.M. 
(1990). The Georgia Tech Payload Operations 
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implementation in C++. Pmeedings of the SCS 
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3. Chu, R.W. (1991). The tutor/aid paradigm: 
Design of intelligent tutoring systems for 
operators of supervisory control systems. PhD. 
Dissertation, CHMSR, School of Industrial and 
Systems Engineering, Georgia Institute of 
Technology, Atlanta, GA. 
4. Fink, PX, (1991). The role of domain 
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Figure 1. The NASA System Graphic Display of GT-VITA 
Procedural Phase 
Practice Phase 
.... 1 
Figure 2. The Pedagogy Network of the TutorIAid Paradigm 
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Intelligent tutoring and aiding in satellite ground control

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