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There are many models of hypertext, distinguished by a number of factors such as the underlying semantic data model (link typing and node typing), the degree of dynamic linking in the hypertext, and how dynamism and other behaviours are implemented. This essay examines a particular approach to dynamism in hypertext, based on the degree of similarity between a text passage in a source node and the text of a target node. It reviews work carried out over the past decade in creating systems for markup-based querying and dynamic hypertext, with particular emphasis on a model of dynamic hypertext that computes hypertext links on the fly using queries.

User interface design and analysis is an inherently interdisciplinary activity that merges cognitive, computing, and engineering sciences. Due to the rapid pace of technological change, there is as yet no science of human-computer interaction and little consensus on what the core knowledge of the discipline should be. In other sciences, the development of taxonomies, such as the taxonomy of living organisms in biology, has proved to be a useful foundation for scientific activity. This paper proposes a taxonomy of user interface terminology as a possible basis for the eventual development of human-computer interaction as a science. This taxonomy includes a model of the basic components of the interface and coverage of some of the major cognitive engineering principles that form the basis for human-computer interaction.

Applications of artificial intelligence (AI) in the cockpit require a deeper understanding of the cognitive processes of the pilot. This paper describes ongoing research concerned with developing cognitive models of pilot behavior that can support the development of expert systems and machine reasoning within the cockpit. An experiment is reported where the behavior of pilots within a flight simulator is observed. Verbal instructions given by the controlling pilot in a “division of labor” task are used to identify salient features of pilot cognitive models of the task. The results of this experiment are interpreted in terms of their implications for the development of future expert systems within the cockpit. Continued research on the cognitive models used by pilots should permit the development of a knowledge base that will assist display design, training programs, and research on mental workload within the cockpit.

The present experiments were designed to test predictions from a model of mental workload. The model predicts non-linear increases in mental workload as perceived distance from a task goal grows and effective time for action is reduced. Diminution of mental workload is achieved by application of effort which brings the task goal into the region of acceptable time/distance constraints for successful resolution. Two experiments are reported which tested these assertions using the timepools performance task. Timepools is unique as a performance task in that it generates a spatial representation of a shrinking temporal target. The independent effects of path length, i.e., the number of sequential targets to be acquired, and shrink rate, i.e., the collapse time during which the circle is halved in area, may be assessed using performance variables such as reaction time (RT), movement time (MT), error rate (E), and the subjective perception of workload. Data from Experiment 1, indicate systematic effects for task related factors across performance and workload measures, although such a pattern was not isomorphically mapped to the a priori assumed difficulty of the task. In Experiment 2, shrink rate and path length had independent effect on RT and MT respectively, which were reflected in components of the individual workload scales. The ramifications with respect to the model are elaborated.

EP-X (Environmental Pollution expert) is a prototype expert system that acts as an expert search intermediary for a bibliographic information retrieval system. It searches for documents in the Chemical Abstracts database in the domain of environmental pollution, providing an intelligent human-computer interface that accommodates a wide variety of user backgrounds and interests. This paper discusses 1) the general problem of bibliographic information retrival, 2) the value of combining Artificial Intelligence (AI) and Human Factors Engineering (HFE) techniques in the design of an intelligent human-computer interface. 3) the general architecture and functioning of EP-X, and 4) examples of specific issues that arise when attempting to apply both AI and HFE techniques to the design of an interactive computer system.

In examining the role of time in mental workload, the authors present a different perspective from which to view the problem of assessment. Mental workload is plotted in three dimensions, whose axes represent effective time for action, perceived distance from desired goal state, level of effort required to achieve the time-constrained goal. This representation allows the generation of isodynamic workload contours that incorporate the factors of operator skill and equifinality of effort. An adaptive interface for dynamic task reallocation is described that uses this form of assessment to reconcile the joint aims of stable operator loading and acceptable primary task performance by the total system. >

Research on the nature of knowledge-based systems for bibliographic information retrieval is summarized. Knowledge-based search tactics are then considered in terms of their role in the functioning of a semantically based search system for bibliographic information retrieval, EP-X. This system uses such tactics to actively assist users in defining or refining their topics of interest. It does so by applying these tactics to a knowledge base describing topics in a particular domain and to a database describing the contents of individual documents in terms of these topics. This paper, then, focuses on the two central concepts behind EP-X: semantically based search and knowledge-based search tactics.

Three well-practiced subjects madesame-different judgments of letter pairs under varying degrees of speed stress. In contrast to the preponderance of false-different errors found using the same method without speed stress (Chignell & Krueger), there were more false-same responses, particularly on similardifferent pairs. The early, or developing, percept looks very similar from one letter to another, apparently because real differences between letters frequently are missed, whereas spurious differences due to missing or unresolved features at encoding or comparison are simply disregarded (missing-feature principle) rather than interpreted as featural mismatches (internal-noise principle). Distinguishing features are added quite late (300 + msec) in processing, just as Eriksen, O’Hara, and Eriksen proposed.

The requirements of maintaining supervisory control of a complex system may sometimes exceed the capability of the human operator for a variety of reasons ranging from temporary distraction from the main task to excessive mental workload. The ergonomic aspect of complex supervisory control can be improved by augmenting the interface with expert systems. This paper outlines the development of an intelligent warning system as one component of an augmented supervisory control system for complex aircraft. The system is designed to alert the pilot to potentially hazardous conditions during instrument landing approaches. The process of task analysis that precedes the implementation of the system is outlined, drawing on the experience of a former military pilot. The results and methods shown here can be generalized to other components of the pilot's task and, more generally, to other complex supervisory control tasks.

Expert systems should find widespread application in human factors, provided the problem of building expert systems (knowledge engineering) is dealt with satisfactorily. The task of knowledge engineering is outlined and five key strategic issues are identified. These strategic issues are discussed from a human factors perspective, and it is shown how current knowledge engineering methods can be extended to include the concerns of human factors. The potential contribution of human factors to knowledge engineering methodology is illustrated with two examples. The first shows how ranking techniques can be adapted to meet the requirements of knowledge elicitation; the second shows how protocol analysis can be used to validate expertise.

Chignell, M.H., Loewenthal, A. and Caspi, A., 1986. The principles of caveat vendor, caveat emptor, and caveat operator in robotic safety. Journal of Occupational Accidents , 8: 79–90. The issue of robotic safety in semi-automated manufacturing environments is considered, using human factors, case study, and accident prevention/liability approaches. The roles of the manufacturer, owner and operator of the robot in ensuring safe operation of robots are examined. General safety guidelines for robotic operation in semi-automated environments are given, but it is recognized that the complexity and variety of human-robot—machine systems necessitates that more rigid and detailed safety standards be set on a case by case basis.

Comparative evaluation of a variety of clustering methods on real and simulated data indicates that the appropriate method for a given set of data must be determined empirically. Selection of an appropriate method generally requires several preliminary analyses. With larger data sets, preliminary analyses on the whole may not be possible. As an alternative one may adopt an interactive strategy and break a large set into manageable subsets.

Despite the promise and prominence of artificial intelligence, successful widely-based applications have been rare. Much of previous artificial intelligence work has concentrated on the demonstration of techniques rather than the development of tools that can be used in systems design, analysis and operation. A systematic program of knowledge compilation in artificial intelligence is proposed where extensible function libraries can be used by professionals in various fields and non-programming specialists in developing artificial intelligence applications.

Afin d'eviter la traduction de la question de l'utilisateur par des mots cles, des groupes de recherche tentent d'utiliser les techniques des systemes de bases de connaissances pour se servir au mieux des systemes de recherche en ligne. Il faut donc faire appel a l'intelligence artificielle pour identifier et coder les connaissances; et il faut pouvoir identifier les facteurs humains afin de concevoir les interfaces appropriees

Current approaches to human-machine interface design are reflective of the traditional dualistic perspective that separates the physical from cognitive characteristics of human functioning. With the development of flexible computing machines and new display technologies, this dualistic perspective can be replaced with one where cognitive and physical aspects of the interface are integrated through the unification of isomorphic structures. This paper reviews the nature of physical and cognitive interfaces and shows how they may be integrated in the design of human-machine systems in order to improve the compatibility between operator and machine.

Cognitive and functional impairment resulting from neurologic injury can have devastating consequences on tasks such as activities of daily living (e.g. mobility, showering, eating, toileting, etc.) and instrumental activities of daily living (e.g. paying bills, grocery shopping, managing medication, etc.). Continuous and non-invasive forms of assessment that are easy to administer and complete can assist in identifying signs of impairment, prevent further decline, and potentially enhance skills. Using a user-centered design process, we designed a game-based screening tool to assist occupational therapists in evaluating an individual's cognitive and functional. We describe the process used and our initial usability findings, as well as suggest guidelines on the design and implementation of screening tools for use in neurorehabilitation.

In this paper we examine the reliability of subjective rating judgments along a single dimension, focusing on estimates of technical quality produced by integrity impairments and failures (non-accessibility, and non-retainability) associated with viewing video. There is often considerable variability, both within and between individuals, in subjective rating tasks. In the research reported here we consider different approaches to screening out unreliable participants. We review available alternatives, including a method developed by the ITU, a method based on screening outliers, a method based on strength of correlations with an assumed “natural” ordering of impairments, and a clustering technique that makes no assumptions about the data. We report on an experiment that assesses subjective quality of experience associated with impairments and failures of online video. We then assess the reliability of the results using a correlation method and a clustering method, both of which give similar results. Since the clustering method utilized here makes fewer assumptions about the data, it may be a useful supplement to existing techniques for assessing reliability of participants when making subjective evaluations of the technical quality of videos.

Serious games are proposed as a more efficient and enjoyable way to carry out cognitive assessment. We compare prediction of cognitive ability with a purpose-built serious game and with a similar game built using a game engine. In an experiment conducted with 28 participants, performance on the two games is assessed relative to three cognitive abilities, using two different tablet sizes and two different input methods. The results for the game-engine variant were similar to the purpose-built game, where both games significantly predicted performance on the three cognitive abilities, and were sensitive to the effects of age. Performance on both games was not significantly affected by tablet size or input method. These results support earlier findings that serious games can provide valid cognitive assessment, and they show that game engines can be used to develop serious games for cognitive assessment, cost effectively and without loss of predictive validity.

The use of cluster analysis for the classification of patients into diagnostic groups remains controversial. Further evidence is provided for assessing the use of cluster analysis in comparison with other multivariate methods. It is suggested that, when appropriately used, cluster analysis is a convenient tool for developing empirically based diagnostic groupings and that the frequently stated limitations of the technique should not invalidate the obtained groupings in such cases.

Publisher Summary This chapter discusses intelligent interface design. The rapid technical progress in the area of human–computer interaction is driven largely by the forces of finance and feasibility. However, innovations themselves are the result of conceptual leaps that turn the possible into the actual. The increasingly cognitive nature of many of the tasks performed at present, combined with interface design possibilities in interactive human–computer tasks promotes the view of the interface as a communication channel, rather than as a physical device that allows control instructions to be passed to the machine and system responses to be observed by the human. Such communication is facilitated by an intelligent agent that mediates between the active participants. Such intelligent interfaces are not predicated on existing technology, as the concept involves an abstract mapping between cognitive and machine representations of tasks. The particular approach taken is a reflection of current needs and technological capabilities, but as tasks and technologies advance, the way that the abstract structure of intelligent interfaces is implemented would also change.

Sequential (vs. simultaneous) presentation of two letters in a physical-identity matching task enhanced the fast-same effect, but did not reduce the preponderance of false-“different” errors or the effect of visual similarity. Thus, the sequential enhancement of the fast-same effect involves an increased efficiency in encoding (d’) owing to letter repetition, as Proctor claimed, rather than a criterion shift (β), and it involves the visual code rather than the name code. The increased efficiency in detecting sameness with sequential presentation might result from spatial separation (e.g., reduced lateral interference and self-termination), though, rather than temporal separation (e.g., priming), However, such spatial factors as letter size and interletter spacing had no consistent effect on the speed advantage forsame pairs, and it was concluded that temporal, not spatial, separation enhances the fast-same effect on sequential trials, Consistent with the response-competition model (Eriksen, O’Hara, & Eriksen), responses were slower and more errorful to similar than to dissimilardifferent pairs, and were equally fast to dissimilar andsame pairs on simultaneous trials.

A method is described for building intelligent person-system interfaces which are responsive to changes in task demand. This approach uses on-line mental workload (MWL) assessment procedures which are comprised of both physiological and performance measures. Comparison of available perceptual and cognitive capacity with the current level of MWL demanded of the operator by the task activates a compensatory procedure that shifts the processing load toward or away from the human in order to optimize overall system performance. This procedure is dependent on the derivation of the error signal which is input into the compensatory system element. The overall success of the intelligent interface relies largely on the validity and accuracy of this error signal. The error signal is based on a fuzzy set-theoretic formulation. A multivariate profile of physiological responses and measures of primary task performance are mapped onto two fuzzy sets. A fuzzy discriminating criterion, related to the fuzzy cluster-analytic model, is used in assigning the membership functions for each of two MWL categories. The resources required by the task are specified in terms of set membership functions for each attentional resource. This information is combined into an error signal used in subsequent dynamic task reallocation.

The successive strokes made in multi-stroke marking menus form gestures. This paper reports on an experimental study that examines how the use of glyphs affects performance in marking menu selection. Glyph familiarity is manipulated by comparing Chinese style and Mark style glyphs across Chinese and non-Chinese users. Performance benefits are found for familiar and memorable glyphs. The results are discussed in terms of their implications for the design of marking menus and associated gestures and for the role of glyphs in facilitating the transition from novice to expert performance in menu selection.

Video mediated communication alters our perception of the way in which we interact and communicate. In contrast to face to face or audio only (e.g., telephone) communication, there is relatively little systematic research on the effect of video conferencing on communication within groups of people at dispersed locations (Harrison, 1991b; Harrison et al, 1992b; Sellen, 1992; Wolf, 1988; Cohen, 1982; Short, Williams, and Christie, 1976). In this paper we describe a study of how participants at three distant locations perceived differences between face to face (within site) and video mediated (between site) communication. Results indicate that participants perceived between site, mediated communication to be unnatural and uncomfortable. They felt there were problems with gaining floor control and with conversation flow. Additionally, participants perceived the between site, mediated communication to be less interactive, less social, and less enjoyable than the face to face, within site communication. The insights gained through this and other case studies, summarized here, will be used to guide our future research. This study is one in a series of field trials and controlled experiments aimed at understanding the human factors issues associated with video communication and the design of such systems.

Background Osteoporosis affects over 200 million people worldwide at a high cost to healthcare systems, yet gaps in management still exist. In response, we developed a multi-component osteoporosis knowledge translation (Op-KT) tool involving a patient-initiated risk assessment questionnaire (RAQ), which generates individualized best practice recommendations for physicians and customized education for patients at the point of care. The objective of this study was to evaluate the effectiveness of the Op-KT tool for appropriate disease management by physicians. Methods The Op-KT tool was evaluated using an interrupted time series design. This involved multiple assessments of the outcomes 12 months before (baseline) and 12 months after tool implementation (52 data points in total). Inclusion criteria were family physicians and their patients at risk for osteoporosis (women aged ≥50 years, men aged ≥65 years). Primary outcomes were the initiation of appropriate osteoporosis screening and treatment. Analyses included segmented linear regression modeling and analysis of variance. Results The Op-KT tool was implemented in three family practices in Ontario, Canada representing 5 family physicians with 2840 age eligible patients (mean age 67 years; 76% women). Time series regression models showed an overall increase from baseline in the initiation of screening (3.4%; P

The effect of key size on text entry on a handheld device while walking and standing was examined in order to answer the following questions: 1) Will the additional workload of walking amplify the effect of input difficulty? and 2) Can walking speed be used as a secondary task measure of mental workload during mobile text entry? 13 participants (7 males and 6 females) input well known sayings (sentences) in English into a handheld device in each of four size conditions, with the text input box ranging in width between 2 and 5 millimetres (mm). Text input speed increased with larger size of text box up to a size of 3mm, and text input speed was faster when standing (vs. walking). The effect of size did not depend on whether participants were walking or standing. Errors were significantly higher for the 2mm size condition but did not vary for the wider sizes, while subjective ease of input increased with increasing input box width, only crossing the midpoint of the rating scale (i.e., more easy than difficult) at an input box width of 3mm. Based on these results it is recommended that a minimum text input box width of 3mm be used for handheld text input. Walking speed during text entry in this study was relatively low (with a mean of 1.77 km/h) but width of text input box had no additional effect on walking speed over and above the general slowing caused by text entry. Thus the answers to both of the main questions posed in this study were in the negative, although the fact that people had to enter text slowed walking speed by a fixed amount (independent of level of input difficulty) that varied between individuals. Implications for measuring workload in mobile text entry tasks are discussed.

This paper describes an empathic software agent (ESA) interface using eye movement information to facilitate empathy-relevant reasoning and behavior. Eye movement tracking is used to monitor user's attention and interests, and to personalize the agent behaviors. The system reacts to user eye information in real-time, recording eye gaze and pupil dilation data during the learning process. Based on these measures, the ESA infers the focus of attention and motivational status of the learner and responds accordingly with affective (display of emotion) and instructional behaviors. In addition to describing the design and implementation of empathic software agents, this paper will report on some preliminary usability test results concerning how users respond to the empathic functions that are provided.

With increasing use of in-vehicle devices, such as cell phones and navigation systems, potential for accident risk due to factors such as inattention and high mental workload are heightened. Notification management systems offer a solution to this problem by mediating notifications based on factors such as task difficulty. However, relevant theories and findings are needed to guide notification management decisions. In this study, 20 participants completed working memory span, cognitive style, and desire for control assessments and then participated in a simulated driving task while responding to phone call notifications. Significant effects of the cognitive factors on how interruptions affected driving performance were found on a number of dependent variables, including measures of minimum time to collision and of longitudinal velocity. Implications for in-vehicle notification management systems are discussed. Keywords: Driver distraction; Language: en

BACKGROUND: Asthma is a common chronic condition. Work-related asthma (WRA) has a large socioeconomic impact and is increasing in prevalence but remains under-recognized. Although international guidelines recommend patient education, no widely available educational tool exists.OBJECTIVE: To develop a WRA educational website for adults with asthma.METHODS: An evidence-based database for website content was developed, which applied evidence-based website design principles to create a website prototype. This was subsequently tested and serially revised according to patient feedback in three moderated phases (one focus group and two interview phases), followed by face validation by asthma educators.RESULTS: Patients (n=10) were 20 to 28 years of age; seven (70%) were female, three (30%) were in university, two (20%) were in college and five (50%) were currently employed. Key format preferences included: well-spaced, bulleted text; movies (as opposed to animations); photos (as opposed to cartoons); an explicit listing of website aims on the home page; and an exploding tab structure. Participants disliked integrated games and knowledge quizzes. Desired informational content included a list of triggers, prevention/control methods, currently available tools and resources, a self-test for WRA, real-life scenario presentations, compensation information, information for colleagues on how to react during an asthma attack and a WRA discussion forum.CONCLUSIONS: The website met the perceived needs of young asthmatic patients. This resource could be disseminated widely and should be tested for its effects on patient behaviour, including job choice, workplace irritant/allergen avoidance and/or protective equipment, asthma medication use and physician prompting for management of WRA symptoms.

Emotional reactions are a key part of user experience. This research examines capture of continuous, quantitative, affective self-reports as a complement to existing methods of evaluating human-system or product interaction. Emotrace is a novel method of measuring emotional responses on the two dimensions of valence and arousal. A pilot study was conducted to inform the design of three emotrace prototypes. This was followed by an experiment where 12 participants watched short videos to elicit emotions, with four self-report conditions (one-slider, two-slider, a touchscreen and no reporting) and physiological capture (heart rate variability and skin conductance). The tools were found to be valid, as ratings reflected the emotion content of the videos. The sliders were found to be more reliable when compared to the touchscreen. We conclude with preliminary recommendations concerning the use of emotrace measurement of emotional user experience to complement current methods of user-interaction evaluation.

Spatial audio has been demonstrated to enhance performance in a variety of listening tasks. The utility of visually reinforcing spatialized audio with depictions of voice locations in collaborative applications, however, has been questioned. In this experiment, we compared the accuracy, response time, confidence in task performance, and subjective mental workload of 18 participants in a voice-identification task under three different display conditions: 1) traditional mono audio; 2) spatial audio; 3) spatial audio with a visual representation of voice locations. Each format was investigated using four and eight unique stimuli voices. Results showed greater voice-identification accuracy for the spatial-plus-visual format than for the spatialand mono-only formats, and that visualization benefits increased with voice number. Spatialization was also found to increase confidence in task performance. Response time and mental workload remained unchanged across display conditions. These results indicate visualizations may benefit users of large, unfamiliar audio spaces.

The Web is a large hypermedia space that is generally explored using search engines. These search engines are evolving to make more effective use of the hypermedia structure of the Web. This paper contributes to this evolution by proposing new methods of topic distillation in structured search based on co-citation and network analysis. We describe a set of 21 network analysis measures of relevance in Web search output. These measures are then compared with human judgments in two studies. In the first study, we compare the average judged relevance of the top 20 search results selected by Google vs. the top 20 results as selected by each of the 21 network analysis measures. All but one of the network analysis measures ("inlink") showed significantly (p

Searching audio data can potentially be facilitated by the use of automatic speech recognition (ASR) technology to generate text transcripts which can then be easily queried. However, since current ASR technology cannot reliably generate 100% accurate transcripts, additional techniques for fluid browsing and searching of the audio itself are required. We explore the impact of transcripts of various qualities, dichotic presentation, and time-compression on an audio search task. Results show that dichotic presentation and reasonably accurate transcripts can assist in the search process, but suggest that time-compression and low accuracy transcripts should be used carefully.

This paper examines a number of ways in which a recent model of stress and human performance may be operationalized to allow experimenters and practioners to assess and predict operator capability in stressful conditions. Particular focus is given to the limits of task capability, as the model emphasizes the task itself as the primary source of stress on the performer. The importance of a model with such predictive capability forms the premise of the work, while the assessment of the present status of this and other models of stress forms the summary.

In replicating a national survey dealing with political attitudes in the New Zealand population (2) the authors had to consider the problems associated with classifying their own newly obtained sample of 451 individuals in terms of the responses elicited by an interview which included 35 attitude items and nine biographical measures. The attitude items were designed to measure responses to the political situation and New Zealand society in general, while the biographical measures were sex, age, marital starus, time spent in employment, number of children, educational qualifications, occupation, source of income, and political affiliations. The three responses allowed for each attitude item were (a) agree, (b) 'uncertain, and (c) disagree. Data were analysed using automatic interaction detection analysis (3) after an alternative clustering method (requiring considerable computational expense) did not uncover any structure in the dam (1). The 35 attitude items were used as the independent variables, with political affiliation being the marker (dependent) variable on which the splitting process was based. Separate analyses were run on rwo nonoverlapping subsets of the data (250 cases and 201 cases). Three clusters were identified as common to both analyses. People in cluster one were generally happy and satisfied with NZ politicians. People in cluster two were dissatisfied with NZ politicians but found politics boring. Those in cluster three were unhappy wich NZ politicians but found politics interesting. A stepwise discriminant analysis was then used, with the 26 son-political attitude responses as the independent variables, to identify non-political attitude differences between the three clusters. The remaining attitude which distinguished between the clusters was the belief that New Zealanders care about one another. Only 23% of cluster one disagreed with the statement that New Zealanders care about one another (the rest either agreed or were uncertain) while 53% and 45% of clusters two and three, respectively, disagreed with the statement. Political affiliation indicated that cluster one corresponded roughly to the right end of the political continuum while cluster three was at the lefr end. Members of cluster rwo divided their support over four political parties. A detailed description of the survey results are available from the authors.