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IJHCS Tables of Contents: 444546474849505152535455565758596061626364

International Journal of Human-Computer Studies 54

Editors:B. R. Gaines
Publisher:Academic Press
Standard No:ISSN 0020-7373; TA 167 A1 I5
Links:Table of Contents
  1. IJHCS 2001 Volume 54 Issue 1
  2. IJHCS 2001 Volume 54 Issue 2
  3. IJHCS 2001 Volume 54 Issue 3
  4. IJHCS 2001 Volume 54 Issue 4
  5. IJHCS 2001 Volume 54 Issue 5
  6. IJHCS 2001 Volume 54 Issue 6

IJHCS 2001 Volume 54 Issue 1

An Exploratory Study of Program Comprehension Strategies of Procedural and Object-Oriented Programmers BIBAK 1-23
  Cynthia L. Corritore; Susan Wiedenbeck
This exploratory study examines the nature of program understanding strategies employed during a series of comprehension and maintenance activities carried out over time. Two dimensions of comprehension were examined: the direction of comprehension and the breadth of comprehension. Thirty expert procedural and object-oriented (OO) programmers studied a program and then performed modifications during two sessions held 1 week apart. The results showed that the direction of comprehension was mixed. The OO programmers tended to use a strongly top-down approach to program understanding during the early phase of familiarization with the program but used an increasingly bottom-up approach during the subsequent maintenance tasks. The procedural programmers used a more bottom-up orientation even during the early phase, and this bottom-up approach became even stronger during the maintenance tasks. The breadth of the programmers' comprehension was found to be greater for the procedural programmers than for the object-oriented programmers. However, after carrying out a series of tasks, all programmers had examined the majority of the program code. The results suggest that, regardless of paradigm, expert programmers eventually build a broad systematic, rather than a localized, view of a program over time.
Keywords: procedural programmers; object-orientated programmers; software maintenance; program comprehension.
Consulting Support During Conceptual Database Design in the Presence of Redundancy in Requirements Specifications: An Empirical Study BIBAK 25-51
  Dinesh Batra; Solomon R. Antony
This study examines the efficacy of a consulting system for designing conceptual databases in reducing data modelling errors. Seventy-two subjects participated in an experiment requiring modelling of two tasks using the consulting system. About half the subjects used the treatment version and the other half used the control version. The control version resembled the treatment version in the look and feel of the interface; however, it did not embed the rules and heuristics that were included in the treatment version.
   Research findings suggest that subjects using the treatment version significantly outscored their control version counterparts. There was an interaction effect between system and prior knowledge-subjects who scored low in a pre-test benefited the most from the treatment version.
   This study has demonstrated that a consulting system can significantly reduce the incidence of errors committed by designers engaged in conceptual database modelling. Further, the system is robust and can prevent errors even in the presence of redundancy in user requirements.
Keywords: Consulting system; expert system; database design; redundancy; requirements specifications; problem-solving.
Making Instructions "Visible" on the Interface: An Approach to Learning Fault Diagnosis Skills through Guided Discovery BIBAK 53-79
  Tom Kontogiannis; Nadia Linou
Operator training in fault diagnosis of complex systems has taken several forms including heuristics, decision flow charts and qualitative plant modelling. Having to comply to a specific learning strategy, however, may increase workload in remembering instructions, constrain people in accommodating their own styles and deny opportunities for exploiting other strategies. A means for increasing learning flexibility and adaptability would be to manipulate the design of the interface in ways that prompt operators to recall past instructions or develop their own strategies. In this study, instructions are made visible on the interface by presenting trainees with a set of tell-tale signs derived from diagnostic heuristics.
   A group of subjects T (new) was trained in using this interface while verbal instructions (e.g. plant theory) were provided to guide discovery of diagnostic rules; a second group T (old) received the same plant theory but practised on a conventional interface. Two other groups used the conventional interface and were trained to apply a set of heuristics with or without the support of a plant theory (H+T and H groups, respectively). Making instructions visible helped the T (new) group to achieve higher accuracy scores than the T (old) group on a subset of fault scenarios. On a near-transfer task, both the T (new) and T (old) groups were superior to the heuristics (H) group. On transfer to another plant, the T (new) group maintained superiority to the heuristics (H) group and exceeded the T (old) group only in a subset of fault scenarios; the differences between the T (new) and the H+T groups were not significant. The results may indicate that making instructions visible could enhance acquisition and also the transfer of complex skills while allowing for flexibility and adaptability in the learning environment.
Keywords: interface design; "visible" instructions; training; guided discovery; fault diagnosis.
Explanations from Knowledge-Based Systems and Cooperative Problem Solving: An Empirical Study BIBAK 81-105
  Shirley Gregor
Explanations are expected to play an important role when knowledge-based systems are used for cooperative problem solving. In this context both human and machine contribute to the procedures, constraints and strategies used in the problem-solving process. An increased need for explanations in this context is congruent with a cognitive-effort perspective and the Production Paradox observed with on-line help systems. This article describes an investigation of the role of explanations in cooperative problem solving. An experimental field study was performed with 41 users and an operational system for personal financial planning. The experiment showed a requirement for cooperative problem solving was associated with greater use of explanations. This effect was more marked with those users who had more fully explored the use of explanations during a preliminary stage of guided problem solving. The frequency of use of explanations in total was positively related to problem-solving performance. There was some evidence that the positive relationship between explanations and improved performance was more noticeable when problems requiring cooperation were undertaken.
Keywords: explanation use; explanations; cooperative problem solving; intelligent systems; knowledge-based systems.
The User Action Framework: A Reliable Foundation for Usability Engineering Support Tools BIBAK 107-136
  Terence S. Andre; H. Rex Hartson; Steven M. Belz; Faith A. McCreary
Although various methods exist for performing usability evaluation, they lack a systematic framework for guiding and structuring the assessment and reporting activities. Consequently, analysis and reporting of usability data are ad hoc and do not live up to their potential in cost effectiveness, and usability engineering support tools are not well integrated. We developed the User Action Framework, a structured knowledge base of usability concepts and issues, as a framework on which to build a broad suite of usability engineering support tools. The User Action Framework helps to guide the development of each tool and to integrate the set of tools in the practitioner's working environment. An important characteristic of the User Action Framework is its own reliability in term of consistent use by practitioners. Consistent understanding and reporting of the underlying causes of usability problems are requirements for cost-effective analysis and redesign. Thus, high reliability in terms of agreement by users on what the User Action Framework means and how it is used is essential for its role as a common foundation for the tools. Here we describe how we achieved high reliability in the User Action Framework, and we support the claim with strongly positive results of a summative reliability study conducted to measure agreement among 10 usability experts in classifying 15 different usability problems. Reliability data from the User Action Framework are also compared to data collected from nine of the same usability experts using a classic heuristic evaluation technique.
Keywords: user action framework; usability evaluation; tool support; evaluation techniques.
Understanding Strategy Selection BIBAK 137-154
  Maxwell J. Roberts; Elizabeth J. Newton
This paper explores several issues associated with explanations of why different people use different strategies for learning and inference tasks. It is suggested that although the concept of cognitive style is a useful starting point, it is unable to account for many findings in the literature, and that any model of strategy usage that confines itself to mechanisms governing strategy selection is incomplete. In addition, it is necessary to take account of strategy availability: Which strategies do people possess, and how do people discover new strategies? Several findings in the literature indicate that strategy discovery is related to general abilities. Specifically, those who are best able to execute a current strategy are those who are the most likely to identify new, more effective methods. It is suggested that many findings that support the notion of cognitive style can be reinterpreted in this light.
Keywords: reasoning; problem solving; individual differences; abilities; strategies; cognitive styles
Extracting Focused Knowledge from the Semantic Web BIBAK 155-184
  Louise Crow; Nigel Shadbolt
Ontologies are increasingly being recognized as a critical component in making networked knowledge accessible. Software architectures which can assemble knowledge from networked sources coherently according to the requirements of a particular task or perspective will be at a premium in the next generation of web services. We argue that the ability to generate task-relevant ontologies efficiently and relate them to web resources will be essential for creating a machine-inferencable "semantic web". The Internet-based multi-agent problem solving (IMPS) architecture described here is designed to facilitate the retrieval, restructuring, integration and formalization of task-relevant ontological knowledge from the web. There are rich structured and semi-structured sources of knowledge available on the web that present implicit or explicit ontologies of domains. Knowledge-level models of tasks have an important role to play in extracting and structuring useful focused problem-solving knowledge from these web sources. IMPS uses a multi-agent architecture to combine these models with a selection of web knowledge extraction heuristics to provide clean syntactic integration of ontological knowledge from diverse sources and support a range of ontology merging operations at the semantic level. Whilst our specific aim is to enable on-line knowledge acquisition from web sources to support knowledge-based problem solving by a community of software agents encapsulating problem-solving inferences, the techniques described here can be applied to more general task-based integration of knowledge from diverse web sources, and the provision of services such as the critical comparison, fusion, maintenance and update of both formal informal ontologies.
Keywords: ontological knowledge; software architecture; domain knowledge; semantic web; information integration; task models.

IJHCS 2001 Volume 54 Issue 2

Editorial: Empirical Studies of Programmers BIB 185-188
  Irvin R. Katz; Marian Petre; Laura Leventhal
Near-Term Memory in Programming: A Simulation-Based Analysis BIBA 189-210
  Erik M. Altmann
Near-term memory (NTM) is proposed as a construct for analysing the memory that experts build up and use as they solve a problem in their domain of expertise. Large amounts of information are processed in such situations, and any particular detail could become important later, so performance is facilitated by maintaining long-term memory access to as much detail as possible. Precise analysis of such memory is difficult to achieve with experimentation or observation alone, so computational simulation is used as the analytical method. A computational process model grounded in cognitive theory (Soar) is constructed to fit extensive fine-grained behavioral data from an expert programmer. The model's structures and processes are then inspected for insights into NTM. Structurally, the model's NTM consists of fine-grain perceptual, semantic, and episodic items whose availability is tied to cues from the encoding context. Quantitatively, much more detail enters NTM than is ever retrieved, but when retrieval does occur it can change the course of behavior. To illustrate applications of the construct, the model is used to examine how a cluttered interface might impose cognitive costs by increasing retrieval demands on memory.
Focal Structures and Information Types in Prolog BIBA 211-236
  Pablo Romero
Several studies have suggested that the mental structures of programmers of procedural languages have a close relationship with a model of structural knowledge related to functional information known as programming Plans. It also has been claimed that experienced programmers organize this representation in a hierarchical structure where some elements of Plans are focal or central to them. However, it is not clear that this is the case for other types of programming languages, especially for those which are significantly different from the procedural paradigm.
   The study reported in this paper investigates whether these claims are true for Prolog, a language which has important differences to procedural languages. Prolog does not have obvious syntactic cues to mark blocks of code (begin/end, repeat/until, etc). Also, its powerful primitives (unification and backtracking) and the extensive use of recursion might influence how programmers comprehend Prolog code in a significant way.
   The findings of the study suggest that Plans and functional information are important for Prolog programmers, but that there is also at least another model of structural knowledge valid for this language. This model of structural knowledge, Prolog schemas, is related to data structure information and it seems that a hierarchical organisation that highlights the relevance of some of its elements as focal is valid for Prolog. These results support the view that comprehension involves the detection of varying aspects of the code and that each of the structures related to these aspects might have their own organization and hierarchical relations.
Studying the Language and Structure in Non-Programmers' Solutions to Programming Problems BIBA 237-264
  John F. Pane; Chotirat "Ann" Ratanamahatana; Brad A. Myers
Programming may be more difficult than necessary because it requires solutions to be expressed in ways that are not familiar or natural for beginners. To identify what is natural, this article examines the ways that non-programmers express solutions to problems that were chosen to be representative of common programming tasks. The vocabulary and structure in these solutions is compared with the vocabulary and structure in modern programming languages, to identify the features and paradigms that seem to match these natural tendencies as well as those that do not. This information can be used by the designers of future programming languages to guide the selection and generation of language features. This design technique can result in languages that are easier to learn and use, because the languages will better match beginners' existing problem-solving abilities.
Rethinking the Evaluation of Algorithm Animations as Learning Aids: An Observational Study BIBA 265-284
  Colleen Kehoe; John Stasko; Ashley Taylor
One important aspect of creating computer programs is having a sound understanding of the underlying algorithms used by programs. Learning about algorithms, just like learning to program, is difficult, however. A number of prior studies have found that using animation to help teach algorithms had less beneficial effects on learning than hoped. Those results surprise many computer science instructors whose intuition leads them to believe that algorithm animations should assist instruction. This article reports on a study in which animation is utilized in more of a "homework" learning scenario rather than a "final exam" scenario. Our focus is on understanding how learners will utilize animation and other instructional materials in trying to understand a new algorithm, and on gaining insight into how animations can fit into successful learning strategies. The study indicates that students use sophisticated combinations of instructional materials in learning scenarios. In particular, the presence of algorithm animations seems to make a complicated algorithm more accessible and less intimidating, thus leading to enhanced student interaction with the materials and facilitating learning.

IJHCS 2001 Volume 54 Issue 3

Visual Representations for Recursion BIBAK 285-300
  Sho-Huan Tung; Ching-Tao Chang; Wing-Kwong Wong; Jihn-Chang Jehng
Visualcode is a visual notation that uses coloured expressions and graphical environments to describe the execution of Scheme programs. RainbowScheme is a program visualization system which is designed to produce visualcode representations of step-by-step execution of Scheme programs. This article presents a new approach of teaching recursion using visualcode and RainbowScheme. Experimental evaluation indicates that viewing RainbowScheme-produced visual traces and requiring students to use visualcode to generate visual evaluation steps of recursive programs can enhance the learners' ability to evaluate recursive programs as well as to solve recursive programming problems.
Keywords: program visualization; recursion; Scheme.
EXCOVE and Using Videos in Knowledge Elicitation BIBA 301-317
  Philip D. Carter; Jon D. Patrick; Frank P. Deane
Expert commentary of videotaped expertise (EXCOVE) is an approach to knowledge elicitation (KE) where expert performance is videotaped and then these videotapes are used to assist the elicitation of knowledge from these and other experts. It was initially formulated to assist in the understanding of the complex area of psychotherapy. Psychodrama was chosen as the form of psychotherapy to trial EXCOVE. Seven hours of videotaped data and 28 h of commentary data were collected and analysed. Evaluation of EXCOVE in the light of these analyses indicated that its unique combination of using video, multiple experts, and interviewing focused on specific events can be useful in KE endeavours. However, there are high overheads involved in the recording, transcription, coding and management of video and commentary data.
A Simple Vision-Based Head Tracking Method for Eye-Controlled Human/Computer Interface BIB 319-332
  K. S. Park; C. J. Lim
Permissive User Interfaces BIBAK 333-350
  Harold Thimbleby
User interfaces often only support one way to do a task when the physical interface or the requirements of the task would permit other ways. In contrast, a user interface that supports multiple approaches is permissive. This paper argues that permissive user interfaces are easier to use-and even when they are not applicable for particular applications, considering permissiveness is a productive design heuristic.
   Many user interfaces are difficult to use yet very easily demonstrated or explained by experts-with the results that users become frustrated because hindsight makes usability problems look like the user's own fault. The lack of permissiveness in such user interfaces explains this paradox.
Keywords: permissiveness; user interface design; design principles; usability; user interface programming.
An Agent-Based Architecture for Multimodal Interaction BIBAK 351-405
  Catholijn M. Jonker; Jan Treur; Wouter C. A. Wijngaards
In this paper, an executable generic process model is proposed for combined verbal and non-verbal communication processes and their interaction. The agent-based architecture can be used to create multimodal interaction. The generic process model has been designed, implemented and used to simulate different types of interaction between verbal and non-verbal communication processes: a non-verbal communication process can add and modify content to a verbal communication process, but can also provide a protocol for the (control of the) verbal communication process. With respect to the communication protocol both stimulus-response behaviour and deliberative behaviour have been modelled and simulated. The semantics of the model has been formalized by three-levelled partial temporal models, covering both the material and mental proceses and their relations.
Keywords: intentional models; agent modelling; non-verbal communication; formalization; human-computer interaction; semantic levels; meta-levels.
Theoretical Basis for Hierarchical Incremental Knowledge Acquisition BIBAK 407-452
  Ghassan Beydoun; Achim Hoffmann
Human experts tend to introduce intermediate terms in giving their explanations. The expert's explanation of such terms is operational for the context that triggered the explanation; however, term definitions remain often incomplete. Further, the expert's (re) use of these terms is hierarchical (similar to natural language). In this paper, we argue that a hierarchical incremental knowledge acquisition (KA) process that captures the expert terms and operationalizes them while incompletely defined makes the KA task more effective. Towards this we present our knowledge representation formalism Nested Ripple Down Rules (NRDR) that is a substantial extension to the (Multiple Classification) Ripple Down Rule (RDR) KA framework. The incremental KA process with NRDR as the underlying knowledge representation has confirmation holistic features. This allows simultaneous incremental modelling and KA and eases the knowledge base (KB) development process.
   Our NRDR formalism preserves the strength of incremental refinement methods, that is the ease of maintenance of the KB. It also addresses some of their shortcomings: repetition, lack of explicit modelling and readability. KBs developed with NRDR describe an explicit model of the domain. This greatly enhances the reuseability of the acquired knowledge.
   This paper also presents a theoretical framework for analysing the structure of RDR in general and NRDR in particular. Using this framework, we analyse the conditions under which RDR converges towards the target KB. We discuss the maintenance problems of NRDR as a function of this convergence. Further, we analyse the conditions under which NRDR offers an effective approach for domain modelling. We show that the maintenance of NRDR requires similar effort to maintaining RDR for most of the KB development cycle. We show that when an NRDR KB shows an increase in maintenance requirement in comparison with RDR during its development, this added requirement can be automatically handled using stored past seen cases.
Keywords: knowledge acquisition; ripple-down rules; situated cognition.

IJHCS 2001 Volume 54 Issue 4

Supporting Diagrammatic Knowledge Acquisition: An Ontological Analysis of Cartesian Graphs BIBAK 457-494
  Peter C.-H. Cheng; James Cupit; Nigel R. Shadbolt
Cartesian graphs constitute an important class of knowledge representation devices. As part of a project on diagrammatic knowledge acquisition we have formulated principles that can underpin the construction, interpretation and use of Cartesian graphs in general and in the specific context of knowledge acquisition. Cartesian graphs are distinguished from other forms of representations by the manner in which they use two-dimensional space to encode quantities on interval or ratio scales. An ontological approach to the analysis of graphs was adopted in which a framework for mapping between the EngMath ontology for engineering mathematics and an ontology of visual components of graphs was developed, the GraphRep framework. GraphRep considers the roles of physical dimensions, measurement units, scales of measurement, functional relations amongst quantities and magnitudes in the generation and interpretation of graphs. It provides a topology of standard graphs and rules for the construction of composite graphs. The utility of the framework is demonstrated by using it: (1) to explain why a particular type of complex composite graph is often used for problem solving in thermodynamics; (2) to analyse the limitations of existing software packages for visualizing data, such as spreadsheets, and to suggest the improvements in their design; and (3) to provide constraints and guidelines for the design of procedures and software to support diagrammatic knowledge acquisition with Cartesian graphs.
Keywords: diagrammatic representations; knowledge acquisition; ontologies; Cartesian graphs.
A Multilevel Input System with Force-Sensitive Elements BIBAK 495-507
  Hui Tang; David J. Beebe; Arthur F. Kramer
Force-sensitive multilevel input elements are introduced as the basic building blocks for compact-size input devices in mobile environments. Compared with switch-type keys, multilevel elements can decrease the number of keys on a keyboard while maintaining the input capacity. A multilevel input mechanism using force-sensitive sensor pads is demonstrated in a three-level three-element tactile chording system with multimodal feedback. Two schemes are introduced to segment the output range of the sensor into levels. For relatively unpracticed users, the scheme based on maximum finger forces gives an average error rate of 20.2% and an input time of 2.24 s for a chord of three inputs. Reclassification of the experimental data using Gaussian segmentation shows that significant improvement of the performance can be expected.
Keywords: user interface; tactile; input device; multilevel; force sensitive.
Towards a Cognitive Approach to Human-Machine Cooperation in Dynamic Situations BIBAK 509-540
  Jean-Michel Hoc
Human-computer interaction research has produced consistent results bearing on a well-established body of knowledge in cognitive science. In contrast, the new research domains of computer-supported cooperative work (CSCW) or human-machine cooperation are harder to develop because the problems to be solved are more complex and the theoretical frameworks more heterogeneous. However, dynamic situations with high temporal constraints create occasions where small teams (including humans and machines) can cooperate on an almost cognitive basis, reducing social or emotional effects. This paper reviews the state of the art on cognitive cooperation to extend an individual cognitive architecture and deal with these situations, combining private and cooperative activities that are highly task-oriented. Cooperation is taken as the management of interference between individual activities to facilitate the team members' sub-tasks and the team's common task when there is one. This review of the literature is a step towards a theoretical approach that could be relevant to evaluate cooperation and to design assistance in diverse domains such as air traffic control or aircraft piloting.
Keywords: human-machine cooperation; human-human cooperation; cognitive cooperation; communication; cooperation assessment; cooperation support; cooperative machine.
User Attitude as a Mediator of Learning Performance Improvement in an Interactive Multimedia Environment: An Empirical Investigation of the Degree of Interactivity and Learning Styles BIBAK 541-583
  Vichuda (Nui) Kettanurak; K. Ramamurthy; William D. Haseman
Multimedia technology-based interactive learning/training programs have recently emerged as major tools for learning in educational settings (schools), at home and for training in corporations. Multimedia aspects and an ability to interact with the programs are claimed to enhance the learning experiences. A central thesis of this study is that such "interactive multimedia learning systems" would significantly improve users' attitudes, and that this, in turn, would enhance their learning achievement. An additional thesis of the study is that the "learning style" of the users will moderate the relationship between interactivity and attitude. This article reports the findings of a controlled quasi-experimental study of the influences of "interactivity" on six different dimensions of user attitude (content, format, user-control, feedback, ease of use and motivation) and performance improvement (achievement-gain). The results indicate that interactivity positively influences user attitude, and some dimensions of attitude translate into enhanced user performance. The study finds some interesting support for the moderating effects of learning styles. Implications and future research directions are discussed.
Keywords: interactivity; multimedia systems; learning; training; learning style; performance; user control; feedback; motivation; ease of use; attitude.
The Influence of Reading Speed and Line Length on the Effectiveness of Reading from Screen BIBAK 585-612
  Mary C. Dyson; Mark Haselgrove
With such a large volume of material accessible from the World Wide Web, there is an urgent need to increase our knowledge of factors influencing reading from screen. We investigate the effects of two reading speeds (normal and fast) and different line lengths on comprehension, reading rate and scrolling patterns. Scrolling patterns are defined as the way in which readers proceed through the text, pausing and scrolling. Comprehension and reading rate are also examined in relation to scrolling patterns to attempt to identify some characteristics of effective readers. We found a reduction in overall comprehension when reading fast, but the type of information recalled was not dependent on speed. A medium line length (55 characters per line) appears to support effective reading at normal and fast speeds. This produced the highest level of comprehension and was also read faster than short lines. Scrolling patterns associated with better comprehension (more time in pauses and more individual scrolling movements) contrast with scrolling patterns used by faster readers (less time in pauses between scrolling). Consequently, effective readers can only be defined in relation to the aims of the reading task, which may favour either speed or accuracy.
Keywords: comprehension; legibility; typography; reading rate; scrolling; skimming.
Using Critical Path Analysis to Model Multimodal Human-Computer Interaction BIBAK 613-636
  Chris Baber; Brian Mellor
In this paper, the concept of multimodal human-computer interaction is explored. It is proposed that multimodality can be defined from human or technology perspectives, which place emphasis on different attributes of the system. Furthermore, in this paper it is argued that the most effective definition of multimodality concentrates on task and goal dependencies. Not only does this permit consideration over and above the technology/human distinction, but also allows consideration of multiple tasks. In order to explore this notion, critical path analysis is used to develop models of multimodal systems. The model describes multimodal HCI, and allows consideration of the effects of modality dependency. The models allow prediction of transaction time under various conditions. Predictions arising from these models are shown to be good fits with data obtained from user trials. Thus, it is proposed that one can develop and evaluate preliminary versions of multimodal systems prior to prototype development.
Keywords: user models; transaction time; critical path analysis; multimodal HCI.
Designing Habitable Dialogues for Speech-Based Interaction with Computers BIBA 637-662
  K. S. Hone; C. Baber
Habitability refers to the match between the language people employ when using a computer system and the language that the system can accept. In this paper, the concept of "habitability" is explored in relation to the design of dialogues for speech-based systems. Two studies investigating the role of habitability in speech systems for banking applications are reported. The first study employed a speech-driven automated teller machine (ATM), using a visual display to indicate available vocabulary. Users made several distinct types of error with this system, indicating that habitability in speech systems cannot be achieved simply by displaying the input language. The second study employed a speech input/speech output home banking application, in which system constraints were indicated by either a spoken menu of words or a "query-style" prompt (e.g. "what service do you require?"). Between-subjects comparisons of these two conditions confirmed that the "menu-style" dialogue was rated as more habitable than the "query-style". It also led to fewer errors, and was rated as easier to use, suggesting that habitability is a key issue in speech system usability. Comparison with the results of the first study suggests that for speech input, spoken menu prompts may be more habitable than similar menus shown on a visual display. The implications of these results to system design are discussed, and some initial dialogue design recommendations are presented.

IJHCS 2001 Volume 54 Issue 5

Editorial: Home Use of Information and Communications Technology BIB 663-664
  Andrew Monk; Robert Kraut
Interacting with the Telephone BIBA 665-699
  Hazel Lacohee; Ben Anderson
This paper describes an empirical study of the use of a mundane domestic technology-the telephone. It combines qualitative and quantitative data gathered as part of a longitudinal study of a panel of 2400 individuals distributed across 1000 UK households. It uses this data to build a rich picture of the ways in which people use the telephone in the late 1990s highlighting the way in which factors such as roles, location, life rhythms and in particular, gender, influence patterns of use and interaction for social purposes. The paper then discusses how these findings are of significance at various levels from the identification of specific design requirements to the conception of what user centred design is and can be in the consumer market.
Breaking Up is Hard to Do: Family Perspectives on the Future of the Home PC BIBA 701-724
  David M. Frohlich; Susan Dray; Amy Silverman
Industry analysts currently disagree about the future of domestic computing. Some predict increasing sales of home PCs while others predict the break-up of the PC into a variety of information appliances. In this paper, we report a study of home PC use which illuminates this issue from the perspective of existing PC-owning families. Eleven PC-owning families from the Boston area were interviewed at home about their current PC use, their attitudes to computers and the location of technology in their homes. We found that the general-purpose nature of the home PC offers something for everybody in the household, and quickly becomes an established part of family life. Indeed, it was so popular in the households we visited that it had resulted in widespread competition for PC time, and had caused parents to worry about how best to control PC and internet access and influence. These behaviours and concerns led adults and children to express quite different preferences for relocating their computing experience around the house. However in both cases the needs were for better access to multifunctional extensions of the main PC. The implications of these findings for home PC and appliance evolution are discussed.
Designing Our Town: MOOsburg BIBA 725-751
  John M. Carroll; Mary Beth Rosson; Philip Isenhour; Craig Ganoe; Dan Dunlap; James Fogarty; Wendy Schafer; Christina Van Metre
MOOsburg is a community-oriented multi-user domain. It was created to enrich the Blacksburg Electronic Village (BEV) by providing real-time, situated interaction and a place-based model for community information. Three versions of MOOsburg have been developed: a classic text-based MOO, a MOO extended to drive a Web-browser, and a Java-based system. The most recent version of MOOsburg is fundamentally different from classic MOOs, supporting distributed system development and management and a direct manipulation approach to navigation. We are currently developing a variety of community-oriented applications, including a virtual science fair and a dispersed natural history museum.
Private and Public Digital Domestic Spaces BIBA 753-778
  Stefan Junestrand; Ulf Keijer; Konrad Tollmar
With the introduction of information and communication technologies into our homes and the different physical and communicative expressions this implies for our living spaces the concepts of being private and of being public become crucial. In this paper, we introduce A Pattern Language, developed by Christopher Alexander in the 1970s, in order to handle these problems systematically. The presentation formally follows Alexander's structure in five cases all related to practical experiments on being private and public at home. We start with a number of concrete user situations related to human-computer interaction. Social and communicative phenomena or possibilities end up in novel design patterns at the interface between an architectural and a technological perspective. The novel patterns presented are primarily based on experiences from practical work on the development of a conceptual dwelling of the future, comHOME, designed and constructed as a full-scale model of a flat. By creating different zones for video-mediated communication, comZONES, the user can control the private and public digital areas varying in time and space. The novel patterns refer to two separate levels. On the first level a specific pattern, called "PRIVATE AND PUBLIC DIGITAL SPACES", is designed as a conceptual floor plan layout. This plan distributes private and public digital spaces for video-mediated communication over the flat. At a second level, four patterns show the integration of the specific comZONES aiming at solving four specific problems with video-mediated communication at home. Our intention is to describe the application of design patterns as a method for analysing and solving novel problems encountered with the introduction of information and communication technologies in our homes. The video-mediated set-ups are not dealt with in depth. They serve mainly as designs that make it possible to apply the design patterns.

IJHCS 2001 Volume 54 Issue 6

Cognitive Activities in OO Development BIBAK 779-798
  David P. Tegarden; Steven D. Sheetz
The cognitive activities performed by systems designers during systems development include problem understanding, problem decomposition and solution specification. One aspect of object-oriented (OO) approaches to system design that appeals to many adopting organizations is the purported naturalness, i.e. the consistency of OO approaches with these cognitive activities of problem solving. Essentially, OO aims to abstract components of the problem of system development to a high level that parallels problem solving in the world the system represents. In other words, knowing how a problem is solved in the real world informs one about how the OO system solves the problem. Thus, the OO development process and the resulting OO model are believed to be consistent with innate cognitive activities and consistent with the problem/real world, respectively. A cognitive mapping method was used to ask graduate students experienced with OO techniques about their perceptions of what is complex (difficult to understand) about OO systems. Their responses include a set of concepts, categories of similar concepts and cognitive maps that reveal what they believe is difficult about using OO techniques. Evaluating these perceptions in terms of the cognitive activities of system design reveals problem decomposition was perceived as the activity that caused the most difficulties related to learning OO techniques. Problem understanding was the goal of the participants, while the solution activity ranked lower in importance but contained many issues essential to systems development and influenced problem understanding.
Keywords: cognitive mapping; object-oriented systems; psychology of programming; information system design issues; information system education.
Are Visual Programming Languages Better? The Role of Imagery in Program Comprehension BIBAK 799-829
  Raquel Navarro-Prieto; Jose J. Canas
This paper presents one experiment to explain why and under which circumstances visual programming languages would be easier to understand than textual programming languages. Towards this goal we bring together research from psychology of programming and image processing. According to current theories of imagery processing imagery facilitates a quicker access to semantic information. Thus, visual programming languages should allow for quicker construction of a mental representation based on data flow relationships of a program than procedural languages. To test this hypothesis the mental models of C and spreadsheet programmers were assessed in different program comprehension situations. The results showed that spreadsheet programmers developed data flow based mental representations in all situations, while C programmers seemed to access first a control flow and then data flow based mental representations. These results could help to expand theories of mental models from psychology of programming to account for the effect of imagery.
Keywords: imagery; mental model; visual programming language; spreadsheets; C; program comprehension.
How do Operators Monitor a Complex, Dynamic Work Domain? The Impact of Control Room Technology BIBAK 831-856
  Kim J. Vicente; Emilie M. Roth; Randall J. Mumaw
This article describes part of a research programme whose goal is to develop a better understanding of how operators monitor complex, dynamic systems under normal operations. In a previous phase, field observations were made at two older nuclear power plant control rooms (CRs) consisting primarily of analogue, hard-wired instrumentation. In this phase, additional field observations were conducted in a newer computer-based CR to determine the impact of CR technology on operator monitoring. Eleven different operators were observed in situ for a total of approximately 88 h. The findings indicate that there are many similarities in the monitoring strategies adopted by operators in the two types of CRs. However, in most cases, these same strategies are performed using different behaviours, thereby showing the shaping effect of the CR technology. A new way of conceptualizing the difference between traditional analogue CRs and modern computer-based CRs is proposed.
Keywords: monitoring; supervisory control; cognitive engineering; process control; nuclear power plants; human-machine interface; control rooms.
The Impact of Status and Audio Conferencing Technology on Business Meetings BIBAK 857-876
  Emma F. France; Anne H. Anderson; Michael Gardner
This field study examining the effects of organizational status and multimedia audio communications technology on communication patterns in business meetings confirms that high status group members verbally dominate discussions and have more control over the flow of the proceedings. However, it reveals a new and surprising finding: multimedia communications technology can in fact exaggerate status constraints in contrast to findings that there is no effect or an equalizing effect on status inequalities of text-based conferencing technology. It appears that in audio conferences, the lack of non-verbal cues that can aid turn-taking combined with (1) the participants' knowledge of the group's status hierarchy and (2) the tendency to compare oneself unfavourably to those of higher status, makes it more difficult for lower status individuals to contribute verbally to discussions than in face-to-face interactions. Such status constraints may have both positive and negative impacts on group communication effectiveness, these and implications for the design and implementation of multimedia communications technology are discussed.
Keywords: communication; status; audio conference; multimedia; technology.
Assessing Users' Subjective Quality of Experience with the World Wide Web: An Exploratory Examination of Temporal Changes in Technology Acceptance BIBAK 877-901
  Michael G. Morris; Jason M. Turner
Contemporary information technology-(IT)-related research has focused on use or user acceptance as a key dependent measure for valuing IT. By understanding the determinants of IT use, we gain descriptive information about successful IT, and prescriptive information for better deploying IT resources and improving their utility. Although there are several competing theories regarding IT use, research findings often cite their inability to account for temporal changes in usage behaviors. Furthermore, contemporary human-computer interaction perspectives often focus on the robust and growing literature surrounding usability and likeability; however, few studies have provided insight into the components of, or antecedents to, the utility dimension. This research attempts to address these gaps by introducing the construct of users'quality of experience as a potential mediator between the determinants of use and actual usage behaviors and their outcomes. A pilot survey concerning Internet usage generated potentially relevant items which were later refined into a questionnaire assessing each item's relative importance to perceptions of quality of experience. Initial indications suggest 10 of the items represent a temporally stable and unidimensional construct. Findings are also interpreted within the context of IT and cognitive/behavioral science perspectives, further providing for face validity of the quality of experience construct.
Keywords: technology acceptance; usability; experience.
What do Web Users Do? An Empirical Analysis of Web Use BIBAK 903-922
  Andy Cockburn; Bruce McKenzie
This paper provides an empirical characterization of user actions at the web browser. The study is based on an analysis of 4 months of logged client-side data that describes user actions with recent versions of Netscape Navigator. In particular, the logged data allow us to determine the title, URL and time of each page visit, how often they visited each page, how long they spent at each page, the growth and content of bookmark collections, as well as a variety of other aspects of user interaction with the web. The results update and extend prior empirical characterizations of web use. Among the results we show that web page revisitation is a much more prevalent activity than previously reported (approximately 81% of pages have been previously visited by the user), that most pages are visited for a surprisingly short period of time, that users maintain large (and possibly overwhelming) bookmark collections, and that there is a marked lack of commonality in the pages visited by different users. These results have implications for a wide range of web-based tools including the interface features provided by web browsers, the design of caching proxy servers, and the design of efficient web sites.
Keywords: web use; WWW, navigation; revisitation