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Behaviour and Information Technology 16

Editors:Tom Stewart
Publisher:Taylor & Francis, Ltd.
Standard No:ISSN 0144-929X
Links:Table of Contents
  1. BIT 1997 Volume 16 Issue 1
  2. BIT 1997 Volume 16 Issue 2
  3. BIT 1997 Volume 16 Issue 3
  4. BIT 1997 Volume 16 Issue 4/5
  5. BIT 1997 Volume 16 Issue 6

BIT 1997 Volume 16 Issue 1

Editorial BIB 1-2
  Tom Stewart
An Interview Study of 'Continuous' Implementations of Information Technology BIBA 3-16
  Cristian Korunka; Andreas Weiss; Sabine Zauchner
Modern workplaces are continuously affected by frequent implementations of information technology. Managing the technology's implementation can have an important moderating function between implementation characteristics and demands as well as effects for the companies and their employees. The development of an interview guide for evaluating technology implementations and their management and a first empirical application of the instrument are presented here. Developed incrementally, the interview guide consists of 139 questions on implementation characteristics, implementation management, and effects. Results of interviews with 59 managers of implementation projects are presented. The implementation projects fulfilled the following criteria: no first-time introduction of information technology, at least 10 employees affected and at least one day of training per employee. Most of the implementations investigated were characterized by increases in qualification demands, changes in work structures, and increases in working time with the new technology. Large implementations characterized by a management using few management tools showed high negative effects for the company (e.g., over-budget), whereas large implementations characterized by few participation indicators showed high negative effects for the employees (e.g., complaints). The interview-guide proved usable for the description of important characteristics of continuous implementations of information technology.
The Evaluation of an Information System for Intensive Care BIBA 17-24
  Judith Ramsay; Hans-Joachim Popp; Bernhard Thull; Gunter Rau
This paper describes the application of human-computer interaction (HCI) research methods in critical care medicine. An evaluation of an information system for the support of cardiological intensive care (The Aachen Information System for Intensive Care -- AISIC) is outlined. AISIC supports the capturing of diagnostic and therapeutic patient data by nursing staff, the requesting of external diagnostic reports, and the retrieval of information for treatment planning performed by physicians (Popp 1994). It was hypothesized that use of the information system would result in quicker task completion times and a reduction in error-making, when compared to the existing paper-based record-keeping system. The evaluation was carried out using eight different forms of data capture, ranging from interview and questionnaire to automatic keystroke logging. The results of the evaluation revealed problems in the prescribing and recording of medication dosage and administration. The resultant redesign of the medication option is discussed, along with implications for improved patient care through the cognitive engineering of medical information systems. The problems encountered in conducting this type of work in a critical care environment are also discussed.
Style Guides and Their Application: The Case of Microsoft 'Windows' and a Remote Tutoring Environment BIBA 25-42
  Martin Colbert
The application of Graphical User Interface styles is supported by 'style guides' -- books which authoritatively specify a basic set of application controls (interface objects) and user input methods, and which advise when and how to use these controls and input methods. Style guides are typically presented as resources that encourage consistency and re-use. This paper reports a recent project which applied the Microsoft 'Windows' style as a de facto standard, rather than a resource. The style was applied in this manner, to offer potential customers a guarantee of usability (of a kind). The project was a success, in that the Windows re-design of a remote tutoring environment out-performed the previous, push button design in key respects in a usability trial. However, with the benefit of hindsight, the Windows re-design was also unnecessarily complex, because the project's view of style compliance was somewhat misleading. If styles are to be used as de facto standards, then it is suggested that projects are provided with explicit concepts of style compliance, compliance rules and compliance assessment procedures.
Evaluating and Improving the Usability of a User Manual BIBA 43-57
  Carl Martin Allwood; Tomas Kalen
This research deals with user-testing as a means to improve the usability of a user manual. In Study 1 we analysed the effects of three different methods for user-testing a commercial user manual to a patient administrative system. Thirty nurses read the manual and noted difficulties found by either (1) making underlinings, (2) writing questions, or (3) verbalizing their comments aloud. Underlinings were more associated with difficult words or concepts, and question writing with broader content issues. Comments verbalized aloud produced the greatest variety of information and the greatest number of comments. In Study 2 we analysed the effects of rewriting the user manual on the basis of the results from the user-tests performed in Study 1 and some general writing principles. The modified manual group spent significantly less time (21% less) on the tasks, issued significantly fewer ineffective commands and made significantly fewer obstructive errors, compared to the original manual group. However, no differences were found with respect to error recovery. These results suggest that user-testing by means of the investigated methods can be an important means to enhance the usability of user instruction manuals.

BIT 1997 Volume 16 Issue 2

Editorial BIB 59-60
  Tom Stewart

Information Presentation -- It's Not What You Show It's the Way That You Show It

Graphing Small Data Sets: Should We Bother? BIBA 61-71
  C. Melody Carswell; Catherine Ramzy
While display designers tend to agree that the communication of large amounts of quantitative information calls for the use of graphs, there is less consensus about whether graphs should be used for small, summarized data sets. In the present study, three groups of 16 subjects viewed 11 sets of time series data presented as tables, bar charts, or line graphs. Data sets varied in size (4, 7, or 13 values) and complexity (number and type of departures from linearity). Subjects provided written interpretations of each of the data sets, and these interpretations were scored for (1) overall number of propositions pertaining to the data set as a whole (global content), (2) number of propositions describing relations within a subset of the data (local content), and (3) number of references to specific data values (numeric content). For the larger (7- and 13-point) data sets, interpretations based on bar charts included the greatest overall global content, but line graph interpretations proved to be most sensitive to the actual information content (complexity) of the data sets. The greater sensitivity of the line graphs was still obtained with four-point data sets; however, this advantage was greater for men than for women. For data sets of all sizes, but especially for the smallest sets, gender differences in interpretation content were obtained. These differences are discussed within the context of more general individual differences presumed to exist in graph-reading strategies.
Reading Music from Screens vs Paper BIBA 72-78
  Richard Picking
The reading of music text from a computer screen was compared to paper in a laboratory controlled study. Computer-based animated score tracking devices of three types were tested, as well as a static screen representation of the music text and its paper-based counterpart. A proof-reading exercise was given to subjects, which involved them listening to pieces of music and identifying intentional errors in the score. Their subjective views were also recorded. No significant difference between the five presentation styles were apparent in the proof-reading study. However, subjects showed a significant preference for animation over paper and static representation. The most popular style of animation was where each note on the score was marked in time to the music. The medium of paper performed better overall than the static screen representation.

Computers in Cars -- Why Don't You Talk to Me?

Spoken Help for a Car Stereo: An Exploratory Study BIBA 79-87
  Govert de Vries; Graham I. Johnson
This paper reports an investigation of the use of spoken (audible) help in an attempt to increase the usability and learnability of a high-end car stereo. To investigate the usefulness of audible spoken help for a car stereo, a simulation was constructed within which experimental help systems were incorporated. To validate the simulation, the 'real' car stereo (an existing consumer product, acting as the control condition) was compared empirically with its simulation. An experiment, using the four conditions of actual product, simulation of actual product, and two simulations employing different spoken help functions was undertaken. Forty participants in a between subjects design, carried out specified tasks with the car stereo version according to experimental condition. User performance, specifically task completion and number of button presses, and subjective reactions were measured. The simulated spoken help versions clearly assisted users with their tasks, and, in general, were responded to favourably when compared to performance with the control simulation and its product equivalent. This exploratory study provided further insight into users' concerns about car stereo usability and the overall results revealed the potential of spoken help facilities for novice users. We can conclude that the use of audible, spoken help, whether as a global option or as a specific 'button help', enhances the performance of, and is acceptable to, novice users of this consumer product type. Finally, this investigation also demonstrated that the use of a (Hypercard) simulation versus the 'real' counterpart (the simulated car stereo) to be generally valid and appropriate for this type of evaluation. In order to progress this direction, examination of the design of spoken help dialogues, user control of these, and issues concerning 'longitudinal' use of the product type are recommended.
In-Vehicle Intelligent Information Technologies as Safety Benefit Systems: Consideration of Philosophy and Function BIBA 88-97
  Nicholas J. Ward; Steve Hirst
Various technological solutions have been advanced to address motorist failings (e.g., sensory limitations, perceptual biases, fatigue, inattention) in the acquisition of safety relevant information. One goal of these systems is to improve traffic safety. Although the functional goal of these technologies is to serve as safety benefit systems, they are foremost information technologies. This paper reviews a number of fundamental issues which underlie the basic nature of these systems as informational services. From the discussion of the philosophy of these systems in relation to the meaning of 'information', a number of functional requirements and limitations of these systems are identified.

An Empirical Study of Interface Designers

Trade-Off Decision Making in User Interface Design BIBA 98-109
  S. Howard
The way in which designers choose between alternatives in user interface design can affect both the design process and also the quality of the outcome, i.e., the user interface. However, little is known about the knowledge drawn on during, or the processes that guide, the choice between design alternatives. This paper presents the results of an empirical study aimed at modelling 'trade-off decision making' in user interface design. It is argued that a single abstract vocabulary can capture important aspects of the rich knowledge drawn on during design problem solving. It is also argued that designers' reasoning during 'choice episodes' is not sophisticated. In choosing between alternatives in design, designers invariably limit the range, or nature, of the alternatives considered. The implications of this finding are discussed.

Computing and Culture

Determinants of User Participation: A Finnish Survey BIBA 111-121
  Juhani Iivari; Magid Igbaria
The relationship between user participation and information systems success has intrigued researchers for two decades. Despite this history there is minimal research on the antecedents of user participation. The tenet of the present paper is that the conditions of user participation are essentially changing. Especially, the European tradition of user participation has focused on blue collar workers rather than professionals and managers. Users are normally assumed to be computer illiterate. The North American tradition has almost exclusively focused on the impact of user participation on information systems success. The present paper examined the significance of organizational level of users, their task variety and computer experience as determinants of user participation including age, gender, education, computer training, organizational tenure and job tenure as control variables. The three determinants were found to have a significant positive effect on user participation, computer experience emerging as the most dominant factor. Gender, education and computer training were discovered to have significant effects mediated by organizational level, task variety and computer experience.

BIT 1997 Volume 16 Issue 3

Editorial BIB 123-124
  Tom Stewart

Three Surveys and a Framework

Public Attitudes Toward Voice-Based Electronic Messaging Technologies in the United States: A National Survey of Opinions about Voice Response Units and Telephone Answering Machines BIBA 125-144
  James Katz; Philip Aspden; Warren A. Reich
We surveyed 912 Americans in the Fall of 1993 about their attitudes toward voice response units (VRUs, also known as voice-based electronic messaging or Interactive Voice Response Units, IVRs) and telephone answering machines or devices (TAMs or TADs). We present data from a national survey to provide an empirical understanding of these novel and significant forms of technologically mediated interpersonal communications. Our results suggest that attitudes toward electronic voice response systems are less closely linked to demographic variables than are attitudes toward answering machines. We uncovered no evidence that the 'information rich' are more positively inclined to electronic voice response systems than the 'information poor'. We also found that attitudes toward the electronic technologies varied strongly by age. The most significant predictor of liking for electronic voice response systems was the quality of one's most recent experience with this technology. We conclude by considering some insights about the formation of attitudes toward these electronic technologies and argue that voice-based services could provide an important access modality to a wide range of electronically-delivered phone services.
An Analysis of the Use of Natural Language Processing Systems in Business BIBA 145-157
  J. Sidhu; C. J. Hinde
The results of a survey conducted amongst managers, users and application developers of Natural Language interrogation systems are presented and analysed. Those that were able to develop successful and effective applications using natural language paid careful attention to the certain stages. It is proposed that these stages are:
  • 1. Systematic analysis of the company's requirements.
  • 2. Effective integration of the natural language technology with the target
        database ensuring current applications are not adversely affected.
  • 3. Introduction to new users of the system. This resulted in realistic user
        expectations and enabled effective use of the natural language software. The advantages and disadvantages of natural language interfaces from an application developer, manager and user perspective are also discussed and recommendations made.
  • Empirical Assessment of Individuals' 'Personal Information Management Systems' BIBA 158-160
      Stephen R. Jones; Peter J. Thomas
    A simple pilot study has been undertaken to investigate the use of 'personal information management technologies' (including both traditional and emerging electronic technologies) via a combination of nominal questionnaire and semi-structured interview schedules. The pilot study suggested that the number of users adopting computer-based personal information management technologies is low, as is the combination of computer-based technologies with traditional paper-based technologies in users' 'personal information management systems'.
    A Design-Oriented Framework for Modelling the Planning and Control of Multiple Task Work in Secretarial Office Administration BIBA 161-183
      Wally Smith; Becky Hill; John Long; Andy Whitefield
    Design-oriented frameworks are a type of Human-Computer Interaction (HCI) discipline knowledge. They are intended to support iterative 'specify-and-implement' design practice, by assisting designers to create models of specific design problems, within a class of design problem. This paper presents a design-oriented framework for a class of HCI design problem, expressed as a the planning and control of multiple task work in secretarial office administration. The planning and control of multiple task work refers generally to how interactive human-computer worksystems specify and select behaviours for performing multiple concurrent tasks. Secretarial office administration is a sub-class of design problem, in which the work supports communications of the organization commissioning the new worksystem. The framework is based on a conception proposed to support an engineering discipline of HCI. The framework conceptualizes the relationship between an interactive worksystem, its domain of work and the effectiveness, or performance, with which work is carried out. The framework was developed from cognitive science and HCI theory and an empirical case-study of an existing secretarial worksystem. The framework expresses the domain of secretarial work as the state transformation of hierarchies of abstract and physical objects, representing communications carried out by the organization. The description of the secretarial work-system expresses the relationship between abstract processes of planning, controlling, perceiving and executing, and abstract representations of plans and knowledge-of-tasks. Planning heuristics and control rules reflect general properties of the dynamic work domain, such as external interruptions and temporary opportunities. The framework also expresses the relationship between these planning and control structures and performance. In its current form, the framework is incomplete, but illustrates an approach to the development of design-oriented knowledge. Using this type of knowledge, a designer may reason about potential solutions to HCI design problems concerning planning and control behaviours for carrying out multiple task work for secretarial office administration.

    BIT 1997 Volume 16 Issue 4/5

    Usability Evaluation Methods

    Guest Editorial BIB 185-187
      Dominique L. Scapin; Tomas Berns
    Tracking the Effectiveness of Usability Evaluation Methods BIBA 188-202
      Bonnie E. John; Steven J. Marks
    We present a case study that tracks usability problems predicted with six usability evaluation methods (claims analysis, cognitive walkthrough, GOMS, heuristic evaluation, user action notation, and simply reading the specification) through a development process. We assess the method's predictive power by comparing the predictions to the results of user tests. We assess the method's persuasive power by seeing how many problems led to changes in the implemented code. We assess design-change effectiveness by user testing the resulting new versions of the system. We conclude that predictive methods are not as effective as the HCI field would like and discuss directions for future research.
    A Planning Aid for Human Factors Evaluation Practice BIBA 203-219
      Ian Denley; John Long
    The work reported here attempts to address Human-Computer Interaction (HCI) design problems by the creation of support for the conceptualization of such problems during evaluation. This support takes the form of a planning aid intended to aid novice human factors practitioners (recently qualified graduates, for example) to evaluate interactive worksystems. The planning aid provides a structure for relating and recruiting techniques used in Human Factors (HF) evaluations. It incorporates relevant information for planning an evaluation (e.g., evaluation methods themselves), and offers advice in the form of heuristics about the use of the methods, their selection, and configuration. The output of the planning aid is an evaluation plan. This paper reports the development of the planning aid, and illustrates its application with a case study. Two assessments of the planning aid with novice HF practitioners are also presented and discussed.
    Ergonomic Criteria for Evaluating the Ergonomic Quality of Interactive Systems BIBA 220-231
      Dominique L. Scapin; J. M. Christian Bastien
    This paper summarizes research work conducted on the design and assessment of a set of usability dimensions called 'ergonomic criteria'. It also provides a detailed description of each of the individual criteria. The paper then mentions the inherent limitations of the method discusses the notion of ergonomic quality, the differences in perspective compared to empirical testing, and identifies the potential users of the method. Finally the paper stresses the limitations in the current state of development of the method and identifies research issues for further improving the method.
    Software Evaluation Using the 9241 Evaluator BIBA 232-245
      Reinhard Oppermann; Harald Reiterer
    There is an increasing need for practical and comprehensive evaluation methods and tools for conformance testing with ISO standards. In this study, we focus on ISO 9241 which is an important ergonomic standard. A brief description shows its content and structure. Practical evaluations include the amount of time and resources which must be managed in software projects, while comprehensive evaluations require that the context of use be considered during the evaluation of user interfaces. In order to complete a comprehensive evaluation of usability, it is necessary to use more than one evaluation method. Therefore, an overview of different evaluation approaches is given, describing their advantages and disadvantages. Finally, the ISO 9241 evaluator is presented in detail as an example of a practical expert-based evaluation method for conformance testing with the ISO 9241 standard, that can be integrated in a comprehensive evaluation approach.
    Comparison of Evaluation Methods Using Structured Usability Problem Reports BIBA 246-266
      Darryn Lavery; Gilbert Cockton; Malcolm P. Atklnson
    Recent HCI research has produced analytic evaluation techniques which claim to predict potential usability problems for an interactive system. Validation of these methods has involved matching predicted problems against usability problems found during empirical user testing. This paper shows that the matching of predicted and actual problems requires careful attention, and that current approaches lack rigour or generality. Requirements for more rigorous and general matching procedures are presented. A solution to one key requirement is presented: a new report structure for usability problems. It is designed to improve the quality of matches made between usability problems found during empirical user testing and problems predicted by analytic methods. The use of this report format is placed within its design research context, an ongoing project on domain-specific methods for software visualizations.
    A Proposed Index of Usability: A Method for Comparing the Relative Usability of Different Software Systems BIBA 267-278
      Han X. Lin; Yee-Yin Choong; Gavriel Salvendy
    Usability is becoming a more and more important software criterion but the present usability measurement methods are either difficult to apply or overly dependent upon evaluators' expertise. Based on human information processing theory, this study identified eight human factors considerations which are relevant to software usability. These considerations as well as the three stages of human information processing theory formed the framework from which our Purdue Usability Testing Questionnaire (PUTQ) is derived. An experiment was conducted to test the validity of PUTQ. The experiment result showed high correlation between PUTQ and the Questionnaire for User Interaction Satisfaction (QUIS version 5.5). In addition, PUTQ detected the differences in user performance between two experimental interface systems, but QUIS failed to do so.Both the questionnaire and answer sheets are reproducible without permission provided this footnote is included in all copies used. Reproduced by permission from Han X. Lin, Yee-Yin Choong, and Gavriel Salvendy, A proposed index of usability: a method for comparing the relative usability of different software systems, Behaviour & Information Technology, 1997, Oct., pp. 267-278.
       Instruction: This questionnaire contains 100 questions about computer interfaces. They are grouped into eight parts. Please answer each of these questions regarding the system to be evaluated in the order they are given, using the answer sheet provided.
       Answer Sheet Instruction: For the 100 questions in the Purdue Usability Testing Questionnaire, your answer for each question regarding the system to be evaluated will consist of the following three sequential parts:
  • (a) Please evaluate each of the 100 questions whether they are applicable to
        the system to be evaluated. If it is not applicable then please proceed
        to the next question. If it is applicable, then please proceed to answer
        the following two questions.
  • (b) Please rate how important is the question to the system being evaluated (1
        is the least important; 3 is most important).
  • (c) Rate the system to be evaluated for effectiveness on the scale of 1 to 7 (1
        for very bad; 7 for very good), or choose 'Not available' is the item is
        not available in the system being evaluated.
  • The MUSiC Performance Measurement Method BIBA 279-293
      Miles Macleod; Rosemary Bowden; Nigel Bevan; Ian Curson
    This paper reports a method for measuring usability in terms of task performance -- achievement of frequent and critical task goals by particular users in a context simulating the work environment. The terms usability and quality in use are defined in international standards as the effectiveness, efficiency and satisfaction with which goals are achieved in a specific context of use. The performance measurement method gives measures which, in combination with measures of satisfaction, operationalize these definitions. User performance is specified and assessed by measures including task effectiveness (the quantity and quality of task performance) and User efficiency (effectiveness divided by task time). Measures are obtained with users performing tasks in a context of evaluation which matches the intended context of use. This can also reveal usability problems which may not become evident if the evaluator interacts with the user. The method is supported by tools which make it practical in commercial timescales. The method has been widely applied in industry, and can be adapted for use early in design, and to evaluate non-computer products and the performance of small work groups.

    BIT 1997 Volume 16 Issue 6

    Editorial BIB 295-296
      Tom Stewart

    Design and Evaluation of User Interface Software

    The Role of Working Memory on Graphical Information Processing BIBA 297-308
      Gerald L. Lohse
    This research extends previous graphics research by examining how individual differences in working memory (WM) capacity and changes in graphic design influence graphical information processing. An experiment compared decision accuracy of two graphic decision aids and an unaided group for a task at two levels of complexity. There were no accuracy differences for the low complexity task. At high levels of task complexity, accuracy depended upon WM capacity and how the graphic aid influenced perception. Eye movement data show information processing differences also are contingent upon graphic design features and WM capacity. We postulate that graphs reduce cognitive overhead by shifting some of the cognitive burden to our visual perception system. More efficient graphical perceptual will improve decision performance only if our cognitive resources are capacity constrained and those cognitive resources are used elsewhere in the problem solving process.
    Age Differences in Reactions to Errors in Computer-Based Work BIBA 309-319
      Kamaljit S. Birdi; Dieter Zapf
    The present study examined the reactions of older and younger workers to the situation of encountering an error during computer-based work. It was expected that older workers would have a stronger negative emotional reaction to such an error due to a combination of age-related factors. In both a questionnaire and an observational study among 134 office workers this was found to be the case. This age relationship remained after controlling for differences in computer experience, attitudes to new technology, education and the number of errors made by participants during a typical computer-based work session. More detailed analyses showed that in response to an error situation, older workers compared to younger ones stated they were significantly less likely to try and solve the problem entirely on their own; this was also partly supported by the observational data. In terms of the available options for helping rectify errors, older workers reported that they were more often likely to use written documentation and rely less on asking other workers. The implications of the findings are discussed in terms of interventions to ameliorate the impact of errors in computer-based work on an older workforce.
    Responses to Comprehension Questions and Verbal Protocols as Measures of Computer Program Comprehension Processes BIBA 320-336
      Teresa M. Shaft
    To study cognitive processes, such as computer program comprehension, researchers often use verbal protocols to collect a process trace. However, the difficulty of collecting and analysing verbal protocol data can discourage even the most resolute researcher. Therefore, alternatives to verbal protocols, such as responses to comprehension questions, are undeniably attractive. Unfortunately, there is little methodological research to justify the use of most alternative methods. The current study compares the use of verbal protocol data with responses to comprehension questions as measures of comprehension process. According to results from the protocol analysis data, programmers used significantly different comprehension processes to understand computer programs in two phases of an experiment. If previous research was correct, then programmers' responses to different types of comprehension questions should reflect the differences in comprehension process. Unfortunately, comprehension process was not reflected in the responses to the questions. Hence, this research confirms that process tracing methods, such as verbal protocols, are a more appropriate method by which to investigate program comprehension processes.

    Design and Evaluation of User Interface Hardware

    The Importance of the Number of Degrees of Freedom for Rotation of Objects BIBA 337-347
      J. P. Djajadiningrat; C. J. Overbeeke; G. J. F. Smets
    In an experiment input methods for object rotation with differing degrees of freedom were assessed. The results are relevant for human-computer interfacing, not only for the finger tip controlled interface proposed in this paper but also for evaluation of existing approaches to rotation. When designing an interface with finger tip controlled rotation of virtual objects, for technical reasons the number of finger tips to be registered should be minimized. Performance of subjects who rotated real objects with different numbers of finger tips was assessed. Subjects rotated a transparent sphere encasing an object according to their personal preference, with three, two or one finger, and restricted to three orthogonal axes. The latter reflects rotation in much current 3D software, whereby only one rotational degree of freedom (DOF) is accessible at a time. Performance in the three and two finger conditions did not differ significantly from the free condition, whilst performance with one finger and orthogonally restricted was significantly lower. However, only the three finger condition was rated as comfortable as the free condition, whilst the two finger, one finger and orthogonally restricted conditions were rated as less comfortable. It is argued that the number of DOFS which can be accessed simultaneously is an important design consideration when quick and intuitive rotation is to be achieved.
    Applying the AHP Approach to Evaluate Human Sensitivity to Chromatic Light BIBA 348-358
      Mao-Jiun J. Wang; Ying-Jye Lee
    The difference threshold of judging chromatic light was evaluated in this study. The experimental factors included target colour, background colour, interspacing, target surface interferences, and luminance level. Results showed that humans were more sensitive to green light than to red or blue light. The differential brightness sensitivity was higher for dark target on bright background than for bright target on dark background. The interspacing between two targets also affected differential brightness sensitivity, but the luminance level of the standard stimulus was found to have no effect on difference threshold. In addition, there was significant individual differences in differential brightness sensitivity. Further, by comparing the results obtained from the Analytic Hierarchy Process (AHP) and the method of constant stimuli, it suggests that the AHP approach was a valid and effective method to assess difference threshold.

    Short Papers

    Software Development: Some Critical Views BIBA 359-362
      Chris W. Clegg; Patrick E. Waterson; Carolyn M. Axtell
    We argue that the software development process can be interpreted as a knowledge-intensive system, incorporating the expertise and skills of many different people over extended periods of time and facing high levels of internal and external uncertainty. Such a perspective enables us to question some current fashions, challenge some powerful and pervasive ideas and assumptions, redefine some problems and open up new debates and opportunities.
    Boosting Trainees' Expectations of Success Through Knowledge of Performance Norms BIBA 363-364
      Karen T. Hilling; Andrew J. Tattersall
    A field study of the role of performance norms in computer training shows that norms have an influential impact on expectations and anticipated satisfaction.