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This article was downloaded by: [Stockholm University Library] On: 27 October 2014, At: 06:50 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Behaviour & Information Technology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tbit20 Short Paper: An expert system within a supportive interface for UNIX Jennifer Jerrams-Smith a a University of Birmingham , PO Box 363, Birmingham, B15 2TT, England Published online: 05 Feb 2007. To cite this article: Jennifer Jerrams-Smith (1987) Short Paper: An expert system within a supportive interface for UNIX, Behaviour & Information Technology, 6:1, 37-41, DOI: 10.1080/01449298708901816 To link to this article: http://dx.doi.org/10.1080/01449298708901816 PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions

Short Paper: An expert system within a supportive interface for UNIX

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This article was downloaded by: [Stockholm University Library]On: 27 October 2014, At: 06:50Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UK

Behaviour & Information TechnologyPublication details, including instructions for authors and subscription information:http://www.tandfonline.com/loi/tbit20

Short Paper: An expert system within a supportiveinterface for UNIXJennifer Jerrams-Smith aa University of Birmingham , PO Box 363, Birmingham, B15 2TT, EnglandPublished online: 05 Feb 2007.

To cite this article: Jennifer Jerrams-Smith (1987) Short Paper: An expert system within a supportive interface for UNIX,Behaviour & Information Technology, 6:1, 37-41, DOI: 10.1080/01449298708901816

To link to this article: http://dx.doi.org/10.1080/01449298708901816

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) containedin the publications on our platform. However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of theContent. Any opinions and views expressed in this publication are the opinions and views of the authors, andare not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon andshould be independently verified with primary sources of information. Taylor and Francis shall not be liable forany losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoeveror howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use ofthe Content.

This article may be used for research, teaching, and private study purposes. Any substantial or systematicreproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in anyform to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

Short paper

An expert system within a supportive interface for UNIX

JENNIFER JERRAMS-SMITHt

University of Birmingham, PO Box 363, Birmingham B15 2TT, England

1. Introduction

It is generally agreed that computers provide useful facilities but that users often do not know how to use them to best effect (Hayes and Szekely 1983, Nickerson 1981). Lack of knowledge may waste the user's time and effort as well as wasting machine resources. One solution to this problem is the provision of a supportive, intelligent interface between the user and the system, so that the user is able to complete the required tasks successfully.

SUSI, a Smart User-System Interface, has been developed as an example of such a system and provides a supportive interface for the UNIX operating system. UNIX was chosen as a particularly suitable system for this provision for the following reasons. Its response to users is somewhat enigmatic and novices are frequently misled by the normal UNIX response to their errors (Hanson et al. 1984). It is likely to be widely used in future, in both academic and commercial environments where it could be available to users who are not only UNIX novices but also computer- naive. An important consideration was that a large user group was available for study at Birmingham University, where each year approximately 50 undergraduates in the Computer Science Department begin to use UNIX.

The SUSI interface is designed as a module which is held between the user and the UNIX system. Its modularity is intended to facilitate future modification (Edmonds 1981). Interaction occurs between its components; interaction between the users and UNIX takes place via the interface.

The SUSI interface provides an exploratory environment for which 'minimalist training' (Carroll 1984) is required since it provides tutorial instruction as soon as it detects that this is necessary and also protects novices from harmful results of their errors (James 1981). It incorporates many of the desirable features of an interface: it provides a personalized response to the user, remains transparent except when help is needed, and protects the user from meaningless and misleading system responses. The interface also detects when the user has an incorrect mental model of the system or is using the system inefficiently, and provides suitable remedial in- struction. A further important aspect is that the interface detects spelling and typing errors (Durham et ul. 1983) and differentiates between these errors and the more serious ones which indicate that the user has a wrong mental model; this is part of the effort to ensure that users are not annoyed by offers of unnecessary advice (Shneiderman 1979).

t Present address: Artificial Intelligence Group, Philips Research Laboratories, Redhill, Surrey, U.K.

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38 Short paper

2. The user model

The provision of an intelligent interface is dependent upon user modelling (Brown and Burton 1978, Sleeman 1983). User modelling allows the detection of users' misconceptions and of underlying requirements as well as stated ones. It allows detection of inefficient behaviour, in terms of both user's time and machine resources. It also enables the generation of suitable instructional material to correct the user's incorrect model of the UNIX system.

The user model developed in this study consists of two components: the gener- alized (static) user model (a model based upon studies of a large user group) plus a specific (dynamic) user model which contains information about the current user.

The specific user model is continuously updated by making comparisons between the behaviour of the current user and that of the generalized user. It con- tains information on the user's level of expertise and a trace of the shell commands for this session along with the corresponding analyses and interpretations made by the interface.

The generalized model of the user is held within the knowledge base of an expert system. It was decided to design and develop an expert system as part of this experi- mental interface for the following reasons. An expert system is able to cope with the incomplete information and knowledge which are likely to typify a supportive inter- face. It is easy to modify the contents of the knowledge base because knowledge is held separately from the control structure. An unexpected advantage was that the explanations facility of the expert system was useful in modifying the rules during the early stage of testing. Production rules were used for representation of knowl- edge because they have a simple control structure and they allow incremental addi- tion of knowledge.

New methods of knowledge acquisition were required because no single expert could provide the information required for the knowledge base: the production rules must interpret the user's input so that errors can be diagnosed and remedied. I t was therefore decided to undertake an extensive study of the behaviour of novice users of UNIX (Smith 1985). Data was collected on the behaviour of 55 novice users of UNIX over four weeks. The novices were undergraduates who had some previous experience with other operating systems. Although their behaviour in general was studied, particular emphasis was placed upon classification and detection of their errors (Norman 1983).

The data for this part of the study consisted of user logs and protocols. Verbal protocols were recorded. The logs contained all commands given to the UNIX shell as well as the time, date and user information. This enabled the logs to be 'tied' to the protocols, which gave additional insights into the reasons for the users' behav- iour.

The logs were carefully studied in order to define categories of user errors and all errors were classified according to these categories. The following are some of the more important error categories:

(1) unable to find help

(2) attempting to use knowledge of other operating systems

(3) having a wrong mental model of the system

(4) inefficient use of the UNIX system

(5) mistyping or misspelling.

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Short paper 39

This study of user behaviour was used in order to formulate the production rules which constitute the generalized (static) user model. The static user model also con- tains information about knowledge which the user might have of other operating systems.

3. The tutorial component

Instruction is provided by the teaching component which consists of two modules: the Intelligent Tutorial System (ITS) and the non-intelligent Computer Assisted Learning (CAL) component.

The CAL module provides a menu of a small number of frequently-used but obscurely-named commands, a listing of the current directory (displayed below the menu) and a new command 'info' which displays simple, short information about the most frequently used UNIX commands.

The ITS provides personalized information in response to deductions made by the expert system about the user's goals. An interactive dialogue is carried on so that the user can modify an entry if necessary. Some explanations are generated and the response is personalized to the extent that examples are given which use files in the current directory. At present many of the explanations are static and are based upon the generalized user model, rather than the specific user model. This has been a satisfactory arrang'ement while the interface has been used by novices who are all of a similar type, but further testing would be required to discover the extent to which it would be effective in other environments. Plans are under way for the improvement and extension of the ITS component.

4. The interface in action

The following indicate the way in which the interface provides support to the user.

(1) An example of detection of mistyping/misspelling: if f2 is a file in the current directory and the user types

"cap f2"

then the interface deduces that 'cat', 'cal', 'cp' and 'cmp' are all possible can- didates if the user has mistyped. However, when the interface checks if the argument matches any commands, it is only 'cat' which has a matching argu- ment. The user is asked if the command is mistyped and is allowed to retype it so that the whole line can be passed to UNIX.

(2) An example of the detection of a misconception and its differentiation from a mistype: if the files in the current directory include 'P and 'lpr5' and the user types

'spell f2 > Ipr'

then there are two possibilities. The interface attempts to establish either that the user is a novice and is confusing pipes and redirection of input (in which case suitable instruction would be offered) or that the user is an expert and has mistyped 'lpr5' (in which case the user would be allowed to retype the mistyped filename).

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(3) An example of inefficient use: if the user types

'cat fl '

followed by

'cat i2'

then the instruction is received that although the commands are correct they could have been effected more efficiently by using

'cat fl f2'

5. Testing and evaluation

Testing and evaluation has been an important element in the process of develop- ment. Pre-testing was used in order to design the full test for this implementation. At this stage the explanations facility of the expert system helped in the modification of rules in the knowledge base. Also, a standard sequence of operations was devel- oped in response to the ways in which users approached the task. The full test, in June 1985, involved a detailed study of 14 Maths/Computer Science undergraduates plus a brief study of about 40 other Computer Science students. For the detailed study there was an experimental group (seven subjects) using the SUSI interface on a VAX, a control group (six subjects) using UNIX on a P D P l l and one further subject who used UNIX but with the benefit of personal tuition. Logs and protocols were recorded in a similar way to that described above.

In summary, when the experimental group was compared with the control group, the results showed that the experimental group

Gave fewer commands overall.

Completed more of the required operations successfully.

Made fewer mistakes.

Made fewer repeats of identical errors. Showed fewer misconceptions about UNIX.

6. Conclusions

The results were validated by statistical tests (Jerrams-Smith 1986) and indicate that SUSI provides a useful supportive interface to UNIX. However, it would be interesting to discover to what extent its performance would be improved by extended user modelling and greater specificity of the ITS.. With this in view, plans are now under way to reimplement the SUSI interface and also to attempt to enable the interface to be more generally applicable to other interactive systems.

References BROWN, J. S., and BURTON, R. R., 1978, A paradigmatic example of an artificially intelligent

instructional system. I J M M S , 10, 323. CARROLL, J. M., 1984, Minimalist training. Datumation (November). DURHAM, I . , LAMB, D. A., and SAXE, J. B., 1983. Spelling correction in user interfaces. Commu-

nications of the A C M , 26 (lo), 764. EDMONDS, E. A,, 1981, Adaptive man-computer interfaces. Computing Skills and the User

Interface, edited by M . J. Coombs and J. L. Alty (Academic Press).

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HANSON, S. J., KRAUT, R. E., and FARBER, J. M., 1984, Interface design and multivariate analysis of UNIX command use. ACM Transactions on Ofice Information Systems, 2, (1).

HA YES,‘^. J., and SZEKELY, P. A,, 1983, Graceful interaction through the COUSIN interface. IJMMS, 19,285.

JAMES, E. B., 1981, The user interface: how we may compute. Computing Skills and the User Interface, edited by M . J. Coombs and J. L. Alty (Academic Press).

JERRAMS-SMITH, J., 1986, The Application of Expert Systems to the Design of Human- Computer Interfaces. PhD thesis, Birmingham University, U.K.

NICKERSON. R. S., 1981, Why interactive computer systems are sometimes not used by people who might benefit from them. IJMMS, 15,469.

NORMAN, D. A,, 1983, Design rules based on analyses of human error. Communications of the A C M , 26, 254.

SHNEIDERMAN, B., 1979, Human factors experiments in designing interactive systems. IEEE Computer, 9.

SLEEMAN, D. H., 1983, Intelligent tutoring systems and student modelling. AISB Conference on A1 and Education, Exeter (unpublished).

SMITH, J. J., 1985, SUSI-a Smart User-System Interface. People and Computers: Designing the Interface, edited by P. Johnson and S. Cook (Cambridge University Press).

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