Choice between driverless v. conventional taxis were investigated in two contexts: (i) forced choice experiment, (ii) structured interviews on attitude. The experiment varied destination urgency, positive/negative autonomous vehicle (AV) news, with scenarios varying cost, safety and pressure. Most participants were conservative, choosing conventional taxis (PT group) in most scenarios, while a minority (AV group) chose driverless taxis. In the scenarios, choice was associated with cost and safety, although cost and safety did not discriminate between PT/AV choice. In the interviews, PT group choice was influenced by dependability, uncertainty about AVs and familiarity while the AV groups’ choice was influenced by positive AV attitudes and assessment of AV reliability. Females tended to be more conservative than males, while several participants considered AVs might be more dependable safety may be challenged in less developed counties. Decisions in the scenarios were rapid, involving < 5 variables, while the interview decisions involved many contextual influences and trade-offs. Key user experience issues were dependability, service quality, and customisation. Fast-path, conventional v. autonomous taxi choice is likely to depend on safety, attitude and prior experience while slow-path attitude formation involves dependability, uncertainty, journey context, and regulation. Several recommendations for AV adoption are given including introduction strategies, marketing and design considerations.

Research Question: Is social media activity related to layers of intimacy in social relationships? Study design: Mixed methods, survey on social relationships with 30 participants who identified up to 20 best/close friends and their use of social media. The same 30 participants were interviewed to gather details of how they communicated with close and best friends, and how they used social media/CMC to maintain their social relationships. Analysis: communication frequency, content and rationale were classified according to the intimacy of relationships between the ego and recipients as best or close friends. Results: Communication with best friends was either face to face or by conversational media (phone, text) in both normal use and emergencies. Emotional support and intimate topics dominated these exchanges. Communication with close friends used broadcast social media (Facebook), text and phone. Face to Face (FtF), phone and text were preferred by the majority of participants for social relationship maintenance. Implications: Dyadic (person to person) communication face to face and via social media, phone and text are vital to provide social and emotional support in intimate social relationships. Social media in particular Facebook broadcast functions play a role in supporting awareness of both intimate and less intimate social relationships.

Purpose To investigate the reasons for users’ choice of mobile applications and how their choice relates to their experience of use. Method A mixed methods study of the factors influencing users’ choice to adopt or abandon mobile applications. Seventy-nine respondents completed a questionnaire recording their top four favourite applications, the frequency of use and user experience measures: aesthetics, content, usability, pleasurable interaction, and overall experience. They also reported up to four abandoned Apps, with any alternatives considered and the reasons for use or abandoning. Follow-up interviews probed the reasons for users’ choice of specific applications. Results/Conclusions Social media was the most favoured category of App, followed by leisure, e-commerce, and communication. Quantitative data shows that content, usability and pleasure predict overall user experience and App acceptance. Interview data indicate that user's choice of downloading and abandoning applications is also influenced by usefulness, usability, content, reliability and contextual factors such as networking and recommendations. Most user App choices appear to be fast-path decisions made without systematic comparison of products.

to investigate the role of values in technology acceptance in general and in the context of the UK Covid Track and Trace App. A survey and interview study was conducted to elicit users’ perceptions of values in general, values in relation to choice of IT products and values which were influenced the decision to download (or not) the NHS Covid-19 Track and Trace App. Other non-value issues such as utility, price and recommendations were considered. Users’ value in life differ slightly from those considered important for selecting IT products. For general IT product decisions, functionality, trust and price with values equality, security and sustainability were important. For the Covid-19 App decision two values, helpfulness and equality, with recommendations/trust and operating system compatibility, were the main influences. Interview data indicated that downloader users were motivated by social responsibility and utility – being able to access workplaces and leisure venues – while non-downloaders had little perceived need for the App, combined with mistrust of the App's provenance (NHS and the Government) linked to security and privacy concerns. The implications for values in technology acceptance decisions are discussed.

A new focus for RE is investigated as ‘soft’ requirements which extends non-functional requirements/soft goals with a collection of people-oriented phenomena: values, motivations, emotions, and other socio-political issues that may influence the requirements specification. The convergence of RE with user experience (HCI) and technology acceptance from the information systems literature is reviewed from a temporal perspective: pre-use, through initial to longer-term use. A taxonomy of soft requirements is proposed that extends non-functional requirements and soft-goal concepts to direct attention towards user characteristics and beliefs that may have implications for functional as well as system support requirements, such as training, help, explanation and trust in software. A timeline model of soft and hard (functional) requirements is presented with a focus on customization, adaptation and other soft requirements to, improve product acceptance and persuade users to take appropriate action. The paper concludes with a research agenda for soft requirements to improve the probability of system acceptance and the effectiveness of applications that aim to influence people’s decisions and behaviour in internet apps and other discretionary-use applications.

We report experience in requirements elicitation of domain knowledge from experts in clinical and cognitive neurosciences. The elicitation target was a causal model for early signs of dementia indicated by changes in user behaviour and errors apparent in logs of computer activity. A Delphi-style process consisting of workshops with experts followed by a questionnaire was adopted. The paper describes how the elicitation process had to be adapted to deal with problems encountered in terminology and limited consensus among the experts. In spite of the difficulties encountered, a partial causal model of user behavioural pathologies and errors was elicited. This informed requirements for configuring data- and text-mining tools to search for the specific data patterns. Lessons learned for elicitation from experts are presented, and the implications for requirements are discussed as “unknown unknowns”, as well as configuration requirements for directing data-/text-mining tools towards refining awareness requirements in healthcare applications.

A reflective analysis on the experience of virtual environment (VE) design is presented focusing on the human–computer interaction (HCI) challenges presented by virtual reality (VR). HCI design guidelines were applied to development of two VRs, one in marine archaeology and the other in situation awareness simulation experiments. The impact of methods and HCI knowledge on the VR design process is analyzed, leading to proposals for presenting HCI and cognitive knowledge in the context of design trade-offs in the choice of VR design techniques. Problems reconciling VE and standard Graphical User Interface (GUI) design components are investigated. A trade-off framework for design options set against criteria for usability, efficient operation, realism, and presence is proposed. HCI-VR design advice and proposals for further research aimed towards improving human factor-related design in VEs are discussed.

'Socio-political' issues, such as emotions, values and people's feelings, are often cited as problems in the RE process. A method is described for analysing such issues. The method consists of a taxonomy of stakeholders' values, motivations and emotions (VME), with process guidance for eliciting and analysing these issues for the RE process and design implications. Values are personal attitudes or long-term beliefs which may influence stakeholder functional and non-functional requirements. Motivations are psychological constructs related to personality traits which may be viewed as stakeholders' long-term goals in RE. Emotions are cues to stakeholders' reactions arising from value/motivation conflicts. The method is supported by a website which illustrates the taxonomy with explanations and scenarios describing problems arising from value conflicts, and from poor understanding of stakeholder values. Two method validation studies were undertaken: first, an evaluation of the website and method by novices and RE experts; and second, case study applications of RE value analysis in real-world industrial practice. The method was used by all practitioners, although in different ways, some used it to create an agenda of issues for analysis while others employed the VMEs to interpret stakeholders' views and manage stakeholder negotiations. The validation studies provide evidence for the acceptability of the method for industrial practitioners, illustrating how value-related problems are identified and analysed effectively by the method. The utility of analysing VMEs is compared to other 'socio-political issues'-oriented methods in RE and methods which focus on monetized values in product requirements.

An experimental investigation into the role of interaction in user experience (UX) with a controlled manipulation of interactivity features (e.g., avatars, interactive video) in a university information website is reported. The more interactive version had better affect and hedonic ratings, even though its perceived usability was worse. Analysis of qualitative data showed users were attracted to the interactive features, although they complained about poor usability. The results of the experiments are discussed to consider the role of interactivity in UX and the differences between users’ quantitative judgments of UX and their comments on interactive features, which reveal different perspectives.

We report the strategies and outcomes of requirements analysis in the SAMS project, which aims to detect early signs of dementia from records of user behaviour derived from monitoring home computer activity. Initial requirements elicitation specified a complex monitoring system in the genre of awareness requirements. As the complexity of the requirements for interpreting user activity became apparent, we revised our strategy towards an iterative refinement driven by analysis of recorded data. We propose that analysis of complex awareness requirements may necessitate a tool-driven approach where data mining software is configured to discover new requirements. Requirements for data mining and data analysis in SAMS are described. Application of the conceptual architecture for directing requirements analysis strategy in complex system with human in the loop for data analysis and adaptation is investigated. The implications for the extended view for RE are discussed with reference to systems with potentially unknown requirements. A research road map is outlined for the convergence of data mining and RE.

Dementia is a serious threat to social sustainability. As life expectancy increases, more people are developing dementia. At the same time, demographic change is reducing the economically active part of the population. Care of people with dementia imposes great emotional and financial strain on sufferers, their families and society at large. In response, significant research resources are being focused on dementia. One research thread is focused on using computer technology to monitor people in at-risk groups to improve rates of early diagnosis. In this paper we provide an overview of dementia monitoring research and identify a set of scientific challenges for the engineering of dementia-monitoring software, with implications for other mental health self-management systems.

A social trust model is presented for investigating social relationships and social networks in the real world and in social media. The results demonstrate that multilevel social structures, with a few strong relationships, more medium ties, and large numbers of weak ties, emerge in an evolutionary simulation when well-being and alliances are rewarded with high levels of social interaction. ‘Favour-the-few’ trust strategies were more competitive than others under a wide range of fitness conditions, suggesting that the development of complex, multilevel social structures depends on capacity for high investment in social time and preferential social interaction strategies.

Smart driver assistive technologies (DAT) have been developed to alleviate accident risk by either reducing driver workload or assessing driver attentiveness. Such systems aim to draw drivers' attention on critical cues that improve decision making. However, in some cases, these systems can have a negative effect due to the extra information load they incur to the driver. Therefore, in addition to specifying the functional requirements for such systems there is an urgent need to address the human requirements. This work describes a simulation-based requirements discovery method that utilises the benefits of a modular simulator that models future designs of DAT.

Novel envisioned systems face the risk of rejection by their target user community and the requirements engineer must be sensitive to the factors that will determine acceptance or rejection. Conventionally, technology acceptance is determined by perceived usefulness and ease-of-use, but in some domains other factors play an important role. In healthcare systems, particularly, ethical and emotional factors can be crucial. In this paper we describe an approach to requirements discovery that we developed for such systems. We describe how we have applied our approach to a novel system to passively monitor users for signs of cognitive decline consistent with the onset of dementia. A key challenge was eliciting users' reactions to emotionally charged events never before experienced by them at first hand. Our goal was to understand the range of users' emotional responses and their values and motivations, and from these formulate requirements that would maximise the likelihood of acceptance of the system. The problem was heightened by the fact that the key stakeholders were elderly people who represent a poorly studied user constituency. We discuss the elicitation and analysis methodologies used, and our experience with tool support. We conclude by reflecting on the affect issues for RE and for technology acceptance.

Advances in more ubiquitous human–computer interface technologies have resulted in the increased use of virtual agents, thus highlighting the need to understand the impact these artificial entities have on the human user in terms of how the user both perceives and behaves toward these characters. We report the results of an experiment based on the Desert Survival task, where the effect of agent attractiveness on persuasion was tested. The results suggest that the attractive agent was significantly more persuasive in changing the participant's opinion than was the unattractive agent. Furthermore, greater behavioral change was observed when the participant interacted with the attractive agent, in terms of persuasiveness, including the attribution of more positive personality traits toward this agent (the attractiveness stereotype). These findings provide further evidence of the powerful influence of the agent's physical appearance on the human user in an interaction-based context. We conclude by pointing toward future research and potential within the area.

This paper investigates general and individual evaluations of User Experience (UX) with interactive web sites. A series of studies investigate user judgment on web sites with different interactivity levels over repeated exposures. The more interactive websites produced more positive affect, had better design quality ratings, which improved with exposure, and were preferred. Differences between the more interactive sites indicated overall UX was influenced by users' preferences for interactive styles, with both sites having enthusiast, potential adopter, and non-adopter users. The implications for models and frameworks of UX are discussed.

Requirements elicitation research is reviewed using a framework categorising the relative `knowness' of requirements specification and Common Ground discourse theory. The main contribution of this survey is to review requirements elicitation from the perspective of this framework and propose a road map of research to tackle outstanding elicitation problems involving tacit knowledge. Elicitation techniques (interviews, scenarios, prototypes, etc.) are investigated, followed by representations, models and support tools. The survey results suggest that elicitation techniques appear to be relatively mature, although new areas of creative requirements are emerging. Representations and models are also well established although there is potential for more sophisticated modelling of domain knowledge. While model-checking tools continue to become more elaborate, more growth is apparent in NL tools such as text mining and IR which help to categorize and disambiguate requirements. Social collaboration support is a relatively new area that facilitates categorisation, prioritisation and matching collections of requirements for product line versions. A road map for future requirements elicitation research is proposed investigating the prospects for techniques, models and tools in green-field domains where few solutions exist, contrasted with brown-field domains where collections of requirements and products already exist. The paper concludes with remarks on the possibility of elicitation tackling the most difficult question of `unknown unknown' requirements.

Users' visual attention measured by eyetracking fixations was investigated in web pages with different designs. Browsing and search conditions were tested. Layout structure influenced attention with fixation densities being concentrated in upper parts of pages according to the layout structure. In sites with open graphical layouts, animations and images dominated attention. In the search condition, attention patterns focused on salient objects and information-scent components leading to the targets. Based on the results, a model of structured directed visual attention was proposed and implemented in the Web Page Analyser tool (WPA) to predict heat maps of visual attention. Validation of the tool demonstrated good accuracy in browse and search modes.

This mini tutorial reviews application of psychological theories in requirements engineering. Theories from psychology of emotion and motivation are introduced and applied in a scenario-based process to analyse affective situations which might be produced by user-oriented RE. Use of agent technology in storyboards and scenario analysis of affective situations is described and illustrated with case studies in health informatics for persuasive technology applications.

A framework for analyzing computer-mediated communication is presented, based on Clark's theory of common ground. Four technologies are reviewed: Facebook, Wikipedia, Blacksburg Electronic Village, and World of Warcraft, to assess their “social affordances,” that is, how communication is supported and how the technologies provide facilities to promote social relationships, groups, and communities. The technology affordances are related to motivations for use and socio-psychological theories of group behaviour and social relationships. The review provides new insights into the nature of long-lasting conversations in social relationships, as well as how representations of individuals and social networks augment interaction.

The aim of this tutorial is to explain in an accessible manner the psychology of people in the context of misunderstandings, politics and social issues that affect software development. It focuses on user-stakeholder interaction techniques for analysis and interpretation of human behaviour, and how psychological knowledge can be used to improve the requirements engineering (RE) process as well as interpreting the implications of human motivations and values for requirements and software systems architecture. Soft issues, such as politics and people's feelings, are often cited as problems in the RE process and as key causes of system failure. It is clear from the RE literature that understanding user beliefs and values is vital for the success of software development. The London Ambulance service is a canonical example of system failure caused, in part, by inadequate understanding of ambulance crews' motivations, values of self esteem and autonomy, and the emotional reaction to lack of involvement in the requirements process, leading to technology failure.

It is a pleasure to introduce this special Festschrift edition in honour of John Long’s contribution to Human Computer Interaction and the science of design more broadly. John Long is one of the founders of our discipline in the UK and contributed significantly to the emergence of HCI in the international arena. As readers will see from the collection of papers which review and develop Long’s work, he questioned the nature of HCI at a deep level in proposing, with John Dowell, his well known and much cited ‘conception’ of the discipline (Long and Dowell, 1989; Dowell and Long, 1998). However, John Long’s HCI research started with work on menu design (Barnard et al., 1977), and frameworks of HCI attracted his attention soon afterwards (Morton et al., 1979). In addition to his theory research, Long’s contributions have included method development exploring the convergence of software engineering and HCI (Lim and Long, 1994), evaluation methodology (Denley and Long, 1997), analysis and design of socio-technical systems (Smith et al., 1997), and applying his expertise and knowledge to CSCW (Lambie and Long, 2002) and requirements engineering (Denley and Long, 2001).

editorial Free Access Share on Editorial: Data mining for understanding user needs Authors: Sherry Y. Chen Brunel University, UK Brunel University, UKView Profile , Robert D. Macredie Brunel University, UK Brunel University, UKView Profile , Xiaohui Liu Brunel University, UK Brunel University, UKView Profile , Alistair Sutcliffe University of Manchester, UK University of Manchester, UKView Profile Authors Info & Claims ACM Transactions on Computer-Human InteractionVolume 17Issue 1March 2010 Article No.: 1pp 1–6https://doi.org/10.1145/1721831.1721832Published:06 April 2010Publication History 7citation1,123DownloadsMetricsTotal Citations7Total Downloads1,123Last 12 Months15Last 6 weeks1 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my Alerts New Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

One of the most important issues in road safety management is the lack of reliable methods for predicting the likelihood of accidents. Road safety assessment systems have been developed; however, these systems only employ historical or retrospective analyses, and the human factor element is weak or missing. Effective safety management requires both holistic and prospective viewpoints, with human factors having an intrinsic role. The main goal of this paper is to contribute toward that need through the application of Bayesian belief networks and road traffic simulation for validating the safety requirements of prospective road designs. The theoretical platform of the method is the concepts of human performance and mental workload and how these affect accident likelihood. This paper presents a novel method and a tool that integrates these two mature technologies, for assessing the safety performance of road designs before they are developed. A case study is included that illustrates the application of the method and tool.

We propose that a fundamental property of human psychology, the need to maintain independent social spheres, imposes constraints on the use of social network sites (SNS). We particularly focus on the consequences of visibility of communications across social spheres, and we hypothesize that technological features of SNS may bring social spheres in conflict, thus leading to increased levels of online social tension. A survey study among Facebook users was conducted to test this hypothesis. Results showed that diversity of the Facebook network predicted online tension. Moreover, the number of kin in a Facebook network was a crucial component because it predicted online tension whereas number of work and social contacts did not. Further, evidence was found to support the idea that tension might impose an upper limit on network size. We conclude with a discussion of these findings and describe how they support the thrust of recent modifications to SNS designs.

An investigation into user attention and design quality in websites is described. The investigation combined reported attention to areas of interest, with free memory recall and a questionnaire to assess whether areas of interest that users attended to were also remembered and rated well in terms of aesthetic design and usability. Users' memory of areas of interest and design features agreed reasonably well with their reported attention. The sites which were rated more attractive overall had an open layout, extensive use of animations which drew users' attention, and good aesthetic design ratings. Aesthetics was the more important determinant for overall attractiveness; whereas content, brand and usability were more important for overall preference. Based on the analysis, design guidelines for directing user attention are proposed.

Understanding the complexities of users' judgements and user experience is a prerequisite for informing HCI design. Current user experience (UX) research emphasises that, beyond usability, non-instrumental aspects of system quality contribute to overall judgement and that the user experience is subjective and variable. Based on judgement and decision-making theory, we have previously demonstrated that judgement of websites can be influenced by contextual factors. This paper explores the strength of such contextual influence by investigating framing effects on user judgement of website quality. Two experimental studies investigate how the presentation of information about a website influences the user experience and the relative importance of individual quality attributes for overall judgement. Theoretical implications for the emerging field of UX research and practical implications for design are discussed.

In this panel, we propose to figure out how requirements engineering and interaction design can be usefully combined. In particular, some people argue that scenarios/ use cases should be concrete, as in story-telling. Others argue for use of "essential" use cases as a methodological approach to interaction and user-interface design. Somewhat in the middle, it is argued that use cases should help acquiring the requirements in the first place. What should the practitioner believe and, in particular, do, in order to develop useful and usable software and systems? Software development and interaction design require different skills and different methods and are typically done by different people. Still, scenario-based design is proposed for several activities relevant for both tasks, such as requirements elicitation, software design, and interaction design. Symbolic modeling in this spirit is actually common to various fields. However, scenario-based approaches vary, especially with regard to their use, e.g., employing abstract use cases or integrating scenarios with functions and goals in a systematic design process. So, the key issue to be raised at the panel is how to combine different approaches, e.g., in scenario-based development, so that the interaction design as well as the development of the user interface and of the software internally result in an overall useful and useable system.

Soft issues, such as politics and people's feelings, are often cited as problems in the RE process. A method aimed at improving elicitation and analysis of such 'soft' issues is described. The method consists of a taxonomy of users' values, motivations and emotions, with process guidance for eliciting and analysing these issues for the RE process.

We describe the experience of using a combination of requirements engineering techniques (scenarios, storyboards, observation and workshops) in an e-science application to develop a geographical analysis tool for epidemiologists. Problems encountered were: eliciting tacit knowledge; and creating new visions and working practices for our users. The combination of techniques worked well, although observation of working practice was not so effective in this scientific domain, where activity is mainly cognitive.

The article introduces a framework for users' design quality judgments based on Adaptive Decision Making theory. The framework describes judgment on quality attributes (usability, content/functionality, aesthetics, customisation and engagement) with dependencies on decision making arising from the user's background, task and context. The framework is tested and refined by three experimental studies. The first two assessed judgment of quality attributes of websites with similar content but radically different designs for aesthetics and engagement. Halo effects were demonstrated whereby attribution of good quality on one attribute positively influenced judgment on another, even in the face of objective evidence to the contrary (e.g., usability errors). Users' judgment was also shown to be susceptible to framing effects of the task and their background. These appear to change the importance order of the quality attributes; hence, quality assessment of a design appears to be very context dependent. The third study assessed the influence of customisation by experiments on mobile services applications, and demonstrated that evaluation of customisation depends on the users' needs and motivation. The results are discussed in the context of the literature on aesthetic judgment, user experience and trade-offs between usability and hedonic/ludic design qualities.

A theoretical framework for assessing the attractiveness of websites based on Adaptive Decision Making theory is introduced. The framework was developed into a questionnaire and used to evaluate three websites which shared the same brand and topic but differed in aesthetic design. The DSchool site was favoured overall and was best for aesthetics and usability. The subjective ratings of the sites were in conflict with the subject-reported comments on usability problems. Subjects were given two scenarios for their preference. They changed their preference from the DSchool to the HCI Group's site for the more serious (PhD study) scenario; however, design background students remained loyal to the DSchool. The implications of framing and halo effects on users' judgement of aesthetics are discussed.

This panel will examine issues related to the conference theme ‘Requirements in the Global Economy’ contrasting academic studies from Dana Damian and Brian Nicholson with industrial experience from Kris Gopalakrishnan (Infosys) and S. Sivaguru, (HCL). Offshore software development is an increasingly important component of the global economy, and India is one of the market leading software suppliers. However, globalisation has exacerbated many familiar problems in requirements engineering: understanding users’ needs, reconciling conflicting goals between stakeholders, validating requirements (and development systems) to meet users needs, and so on. Distributed requirements engineering where customers and suppliers are separated by distance, time, culture and frequently language needs improved solutions to old problems of enhancing mutual understanding between customers and suppliers, managing the process and fostering long term mutually beneficial relationships.

Development of an evolutionary computing tool for requirements analysis and optimization of component-based systems is described. The tool assesses scenarios that represent potential designs and their operational behavior, as well as how the designs perform in a range of environmental conditions. Designs are optimized for three objective functions: 1) reliability; 2) performance time; and 3) costs. Use of the tool is illustrated in a systems engineering case study to derive optimal design for a naval command and control system that includes human operator roles as well as technology components.

The system reliability analyzer tool for analyzing the reliability of system designs is described and its use illustrated in a system engineering case study of a naval command and control system. The performance of systems consisting of human operators and technology components is assessed by Bayesian nets, which calculate error probabilities from inputs of agent properties and environmental conditions. The tool tests scenarios representing the system design and its operational behavior, which is modeled as cycles of command and control tasks. The tool indicates weak points in the scenario sequence and assesses the reliability of one or more system designs with a set of operational scenarios and a variety of environmental conditions

In this paper we describe an evaluation of two websites with the same content but different interface styles (traditional menu-based and interactive metaphors). A formative usability evaluation was carried out with heuristic assessment of aesthetics, and questionnaire assessment of aesthetics, content, information quality, usability and post-test memory. The study revealed that perception of information quality is affected by the interaction style implemented in the interface, in a manner resembling the halo effect in person perception. Implications for website design and evaluation are discussed.

The new usability agenda is driving empirical and experimental studies into a growing range of quality criteria such as engagement, user experience, and aesthetics. Some see this as a positive move to theorise about the nature of good design qualities, and to objectively test such hypotheses on the new usability theme. However, others (e.g. [1], [2]) have argued for interpretation-based inquiry into user engagement and experience on the grounds that such phenomena can only be understood by investigations into contexts of use which defy quantitative approaches. Many in the design community would agree with them and go further to argue that quality in design is a matter of creativity and can not be measured or theorised per se; instead, research should focus on understanding and improving the process of design. This panel will debate the tensions between these positions and explore possible common ground between them as a contribution towards the research agenda that is being debated in the DIS conference series.

This paper covers the research problem of supporting users' decision making in E-Commerce systems with complex choices, and design of an Adaptive Decision Support System (ADSS) which matches the appropriate tool support and decision strategy advice to the user's preferences and motivations. A preliminary requirements investigation will be described which used an adapted Wizard of Oz approach to test users' reaction to mock-ups of the ADSS with and without system advice. The requirements study tested users' reaction to the proposed tools and whether they were influenced by the system advice. This discussion will be followed by a description of the design and development of the ADSS and its architecture. The paper concludes with plans for future research.

An experimental comparison of interaction in the real world and a CAVE virtual environment was carried out, varying interaction with and without virtual hands and comparing two manipulation tasks. The double-handed task was possible in the real world but nearly impossible in the VE, leading to changed behavior. The single-handed task showed more errors in the VE but few behavioral differences. Users encountered more errors in the CAVE condition without the virtual hand than with it, and few errors in the real world. Visual feedback caused many usability problems in both tasks. The implications for VE usability and virtual prototyping are discussed.

A framework for requirements analysis is proposed that accounts for individual and personal goals and the effect of time and context on personal requirements. The implications of the framework on system architecture are considered as three implementation pathways: functional specifications, development of customisable features and automatic adaptation by the system. These pathways imply the need to analyse system architecture requirements. Different implementation pathways have cost-benefit implications for stakeholders, so cost-benefit analysis techniques are proposed to assess tradeoffs between goals and implementation strategies. The use of the framework is illustrated with two case studies in assistive technology domains: e-mail and a personalised navigation system.

This paper describes a method and a tool for validating nonfunctional requirements in complex socio-technical systems. The system requirements analyzer (SRA) tool validates system reliability and operational performance requirements using scenario-based testing. Scenarios are transformed into sequences of task steps and the reliability of human agents performing tasks with computerized technology is assessed using Bayesian belief network (BN) models. The tool tests system performance within an envelope of environmental variations and reports the number of tests that pass a benchmark threshold. The tool diagnoses problematic areas in scenarios representing pathways through system models, assists in the identification of their causes, and supports comparison of alternative requirements specifications and system designs. It is suitable for testing socio-technical systems where operational scenarios are sequential and deterministic, in domains where designs are incrementally modified so set up costs of the BNs can be defrayed over multiple tests.

We elaborate a proposal for capturing, extending, and reusing design knowledge gleaned through usability testing. The proposal is specifically targeted to address interface design for notification systems, but its themes can be generalized to any constrained and well-defined genre of interactive system design. We reiterate arguments for and against using critical parameters to characterize user goals and usability artifacts. Responding to residual arguments, we suggest that clear advantages for research cohesion, design knowledge reuse, and HCI education are possible if several challenges are overcome. As a first step, we recommend a slight variation to the concept of a critical parameter, which would allow both abstract and concrete knowledge representation. With this concept, we demonstrate a feasible approach by introducing equations that elaborate and allow evolution of notification system critical parameters, which is made operational with a variety of usability evaluation instruments. A case study illustrates how one general instrument allowed system designs to be meaningfully compared and resulted in valuable inferences for interface reengineering. Broad implications and conclusions about this approach will be of interest to others concerned with using critical parameters in interface design, development of notification systems interfaces, or approaches to design rationale and knowledge reuse.

This work describes an approach for visualisation specification and retrieval, with the aim of supporting the reuse of visualisation design knowledge. For this purpose, the approach focuses on requirement abstraction, visualisation characterisation, mapping rules and visualisation retrieval. Requirement abstraction represents knowledge for problem understanding. Visualisation characterisation and mapping rules represent the design knowledge. Visualisation retrieval makes the knowledge reuse effective. The novelties include using generic features for the visualisation specification and proposing a vector model for visualisation retrieval.

This paper presents a heuristic method for evaluating virtual environment (VE) user interfaces. The method is based on Nielsen's [Usability Inspection Methods, 1994] usability heuristics, extended by VE-specific principles proposed by Sutcliffe and Kaur [Behaviour and Information Technology 19 (2000) 415–426]. Twelve heuristics are presented which address usability and presence issues. An inspection-based evaluation method is described and illustrated with three usability case study assessments, the last of which rates the applicability and validity of the heuristics by several evaluators. Use of the method uncovered several usability problems and trapped the most serious errors. Finally, VE applications integrating measures of usability and presence are discussed.

We explain the concepts and process of scenario based requirements engineering. Definitions of scenarios are reviewed, with their informal and more formal representations, and roles in the requirements process. The relationships between scenarios, specifications and prototypes is explored, and set in the perspective of human reasoning about requirements. Methods for scenario based RE are described and one method, SCRAM, is covered in more depth. We conclude with a look forward to the future of scenario based RE and research directions.

The evolutionary requirements analyser (ERA) applies evolutionary computing techniques to automatically select optimal combinations of human and machine agents in a system model to match nonfunctional requirements (NFRs). The tool assesses the reliability, performance times and cost of different system models by executing many model variants, as evolving forms, with scenarios and different combinations of environmental variables. Better performing models are selected, to converge on an optimal solution. Use of the tool is illustrated with a case study of requirements analysis for component selection in a command and control system.

This paper follows the scenarios and task models debate by reviewing the contributions of task modelling and scenario based approaches from a cognitive perspective. A framework of cognitive affordances is introduced to discuss the merits and limitations of each approach. An extension of the modelling theme, generic task models, is proposed to augment the contribution of knowledge reuse to the design process. The paper concludes by discussing how scenario based design might complement task analysis and reuse of task based knowledge.

A prototype e-mail system was developed for cognitively disabled users, with four different interfaces (free format, idea prompt, form fill and menu driven). The interfaces differed in the level of support provided for the user and complexity of facilities for composing e-mail messages. Usability evaluation demonstrated that no one interface was superior because of individual differences in usability problems, although the majority of users preferred interfaces which did not restrict their freedom of expression (free format). In contrast to traditional evaluation studies, no common pattern of usability errors emerged, demonstrating the need for customisation of interfaces for individual cognitively disabled users. A framework for customising user interfaces to individual users is proposed, and usability principles derived from the study are expressed as claims following the task artefact cycle.

We introduce evolutionary computation into requirements engineering and propose a process for selecting an optimal set of components to satisfy fitness criteria of system reliability. The system architecture and algorithms are described with a case study of a command and control system. The results of the evolutionary requirements analysis are discussed.

This paper addresses the problem of requirements engineering for complex socio-technical systems where an optimal set of technology components and human operators have to be selected to achieve system goals. Goals are achieved by tasks that are expressed as operational scenarios with variations in environmental conditions. The approach taken is to develop a probabilistic model of system reliability as a Bayesian Belief Network (BBN). The BBN model predicts human and machine reliabilities, given input variables representing the scenario and ranges of environmental conditions (i.e. weather, climate, etc.). A software tool, the System Reliability Analyser (SRA) is described that runs a set of scenarios against the BBN models while systematically varying the ranges of 12 input variables specifying properties of human operators such as training, technical equipment specification and environmental conditions. The tool reports human and technical equipment specifications that "survive" the scenario testing at a reliability level higher than a user-defined level. A case study evaluation of the tool is reported using a naval command and control domain, in which different combinations of human roles and equipment requirements specifications are automatically validated against a set of scenarios describing missile attacks on a navy frigate. The implication of using BBN technology and the SRA tool for automating socio-technical system requirements validation and optimising requirements selection in component-based systems is discussed.

A method for analysing requirements for complex sociotechnical systems is described. The method builds on the I* family of models by explicitly modelling communication between agents by discourse act types. System (i*) models and use cases are developed which describe the dependencies between human and computer agents in terms of a set of discourse acts that characterise the obligations on agents to respond and act. For human-computer communication, the discourse acts indicate functional requirements to support operators. For human agents, the acts specify their obligation to act and constraints on action. The method provides analytic techniques and heuristics to assess agent workloads in terms of the tasks and communication they have to perform. Scenarios are run against the system model by walking through the chain of operator tasks and communication links to produce time estimates and failure probabilities, where the demands of scenarios impose excessive loads on human operators. The method is illustrated with a case study of a naval command and control system.

A walkthrough method for evaluating virtual reality (VR) user interfaces is described and illustrated with a usability assessment of a virtual business park application. The method is based on a theory of interaction that extends Norman's model of action. A walkthrough analysis method uses three models derived from the theory. The first model describes goal-oriented task action, the second exploration and navigation in virtual worlds, while the third covers interaction in response to system initiative. Each stage of the model is associated with generic design properties that specify the necessary support from the system for successful interaction. The evaluation method consists of a checklist of questions using the properties and following the model cycle. Use of the method uncovered several usability problems. Approaches to evaluation of VR applications and future work are discussed.

An evaluation method is proposed based on walkthrough analysis coupled with a taxonomic analysis of observed problems and causes of usability error. The model mismatch method identifies usability design flaws and missing requirements from user errors. The method is tested with a comparative evaluation of two information retrieval products. Different profiles of usability and requirements problems were found for the two products, even though their overall performance was similar.

An empirical investigation of information retrieval (IR) using the MEDLINE1 database was carried out to study user behaviour, performance and to investigate the reasons for suboptimal searches. The experimental subjects were drawn from two groups of final year medical students who differed in their knowledge of the search system (i.e., novice and expert users). The subjects carried out four search tasks and their recall and precision performance was recorded. Data was captured on the search strategies used, duration, and logs of submitted queries. Differences were found between the groups for the performance measure of recall in only one of the four experimental tasks. Overall performance was poor. Analysis of strategies, timing data, and query logs showed that there were many different causes for search failure or success. Poor searchers either gave up too quickly, employed few search terms, used only simple queries, or used the wrong search terms. Good searchers persisted longer, used a larger, richer set of terms, constructed more complex queries, and were more diligent in evaluating the retrieved results. However, individual performances were not correlated with all of these factors. Poor performers frequently exhibited several factors of good searcher behaviour and failed for just one reason. Overall end-user searching behaviour is complex and it seems that just one factor can cause poor performance, whereas good performance can result from suboptimal strategies that compensate for some difficulties. The implications of the results for the design of IR interfaces are discussed.

The article argues that new approaches for delivering HCI knowledge from theory to designers will be necessary in the new millennium. First the role of theory in HCI design to date is reviewed, including the progress made in cognitive theories of interaction and their impact on the design pr ocess. The role of bridging models that build on models of interaction is described, but it is argued that direct application of cognitive theory to design is limited by scalability problems. The alternative of representing HCI knowledge as claims and the role of the task-artefact approach to theory-based design are introduced. Claims are proposed as a possible bridging representation that may enable theories to frame appropriate recommendations for designers and, vice versa, enable designers to ask appropriate questions for theoretical research. However, claims provide design advice grounded in specific scenarios and examples, which limits their generality. The prospects for reuse becoming an important mode of development and the possible directions in generalizing claims for reuse are discussed, including generalizing claims beyond their original context, providing a context for reuse of claims by linking them to generic task and domain models. It is argued that generic models provide a way forward for developing reusable libraries of interactive components. The approach is illustrated from a case study of extracting claims from one information ret rieval application, generalizing claims for future reuse in information-searching tasks, and reapplying claims in the Web-based Multimedia Broker application. The article concludes by proposing that HCI knowledge should be theory-grounded, and development of reusable “designer-digestible” packets will be an important contribution in the future.

This paper explores how contact points or co-references between an animation and text should be designed in web pages. Guidelines are derived from an eye tracking study. A dynamic HTML authoring tool is described which supports these requirements. An evaluation study is reported in which four designs of animation in web pages were tested.

This paper reports a method of assessing the implications for human error on system requirements, a topic not usually considered during requirements engineering (RE). In our previous work, we proposed a taxonomy of influencing factors that might contribute to human error. This paper takes the taxonomy and elaborates it to suggest generic requirements to deal with problems in different layers of the taxonomy. Components of the taxonomy are combined into a causal model for error, represented as a Bayesian Belief Net (BBN). BBNs model the error influences arising from user knowledge, ability and the task environment. These are combined with factors describing the complexity of action and user interface quality in scenarios of projected system usage. The BBN model predicts probabilities of slips and mistakes. These are assessed according to action types in the scenario to suggest generic requirements to prevent the error or to deal with its consequences.

There is a need for interface design guidance for virtual environments, in order to avoid common usability problems. To develop such guidance an understanding of user interaction is required. Theoretical models of interaction with virtual environments are proposed, which consist of stages of interaction for task/goal oriented, exploratory and reactive modes of behaviour. The models have been evaluated through user studies and results show the models to be reasonably complete in their predictions about modes and stages of interaction. Particular stages were found to be more predominant than others. The models were shown to be less accurate about the exact flow of interaction between stages. Whilst the general organisation of stages in the models remained the same, stages were often skipped and there was backtracking to previous stages. Results have been used to refine the theoretical models for use in informing interface design guidance for virtual environments.

Scenarios, in most situations, are descriptions of required interactions between a desired system and its environment, which detail normative system behaviour. Our studies of current scenario use in requirements engineering have revealed that there is considerable interest in the use of scenarios for acquisition, elaboration and validation of system requirements. However, scenarios have seldom been used to study inappropriate or exceptional system behaviour. To account for non-normative or undesired system behaviour, it is vital to predict (‘what can go wrong’) and explore the existence or occurrence of ‘exceptions’ in a scenario when the system System, here, is not just a pure software system but is a socio-technical system which has social technical and organisation dimensions with the user as an integral part of the system. In this article, we present a prototype software tool called CREWS–SAVRE for systematic scenario generation and use. We describe the innovative features of the tool and demonstrate them with an example of tool’s use. Further, we have identified three kinds of exceptions: generic, permutation and problem exceptions, and have derived complex taxonomies of problem exceptions. We have populated SAVRE with the taxonomies of generic, permutation and problem exceptions. The exceptions can be chosen by the requirements engineer to include them in the generated scenarios to explore the correctness and completeness of requirements. In addition, the taxonomies of problem exceptions can also serve as checklists and help a requirements engineer to predict non-normative system behaviour in a scenario.

We describe a method of assessing the implications for human error on user interface design of safety-critical systems. In previous work we have proposed a taxonomy of influencing factors that contribute to error. In this article, components of the taxonomy are combined into a mathematical and causal model for error, represented as a Bayesian Belief Net (BBN). The BBN quantifies error influences arising from user knowledge, ability, and the task environ-ment, combined with factors describing the complexity of user action and user interface quality. The BBN model predicts probabilities of different types of errorslips and mistakes for each component action of a task involving user-system interaction. We propose an Impact Analysis Method that involves running test scenarios against this causal model of error in order to determine user interactions that are prone to different types of error. Applying the proposed method will enable the designer to determine the combinations of influencing factors and their interactions that are most likely to influence human error. Finally we show how such scenario-based causal analysis can be useful as a means of focusing on relevant guidelines for safe user interface design. The proposed method is demonstrated through a case study of an operator performing a task using the control system for a laser spectrophotometer.We describe a method of assessing the implications for human error on user interface design of safety-critical systems. In previous work we have proposed a taxonomy of influencing factors that contribute to error. In this article, components of the taxonomy are combined into a mathematical and causal model for error, represented as a Bayesian Belief Net (BBN). The BBN quantifies error influences arising from user knowledge, ability, and the task environ-ment, combined with factors describing the complexity of user action and user interface quality. The BBN model predicts probabilities of different types of errorslip for each component action of a task involving user-system interaction. We propose an Impact Analysis Method that involves running test scenarios against this causal model of error in order to determine user interactions that are prone to different types of error. Applying the proposed method will enable the designer to determine the combinations of influencing factors and their interactions that are most likely to influence human error. Finally we show how such scenario-based causal analysis can be useful as a means of focusing on relevant guidelines for safe user interface design. The proposed method is demonstrated through a case study of an operator performing a task using the control system for a laser spectrophotometer.

ABSTRACT The paper summarises empirical research that led to guidelines for directing the viewing/reading sequence in multimedia presentations. A method for scripting or evaluating multimedia presentations is described and illustrated with a case study. A design advisor tool based on this work is used to critique a sample MM presentation. A tool validation study with novice designers is reported. KEYWORDS Presentation Design, Guidelines, Tool support INTRODUCTION One of the problems in the design of expository Multimedia (MM) interfaces is knowing whether the presentation will successfully deliver appropriate information to the user. In a review of studies on MM instructional systems, Kozma [6] proposes a ‘micro-level’ approach will be required to produce effective multimedia : ‘...media decisions for integrated multimedia will be micro-level decisions... .._ of appropriate media that can respond to specific cognitive needs and task requirements.’ The problem is thus, what information can the user extract from a presentation, and how can we assist MM designers in making these micro- level decisions when producing their presentations ? Our work has attempted to address these issues by empirically investigating attention to MM presentations and in producing design guidelines. However, experience tells us that guidelines alone are rarely effective. The paper thus also reports research on guideline delivery via methods and tools. The paper has two main sections. The Krst section describes the design method we have developed to encapsulate the guidelines. Results of our previous eye tracking studies on MM presentations are summarised to introduce the guidelines and provide an example application to illustrate operation of the method and tool. The second part of the paper describes a prototype advisor tool which embeds the guidelines as rules. The tool critiques the presentation, providing warnings and advice during authoring. The paper concludes with an evaluation of the tool’s effectiveness in helping novice designers

Article Free Access Share on Making contact points between text and images Authors: Pete Faraday The Centre for HCl Design, City University, Northampton Square London, EC1 OHB, UK The Centre for HCl Design, City University, Northampton Square London, EC1 OHB, UKView Profile , Alistair Sutcliffe The Centre for HCl Design, City University, Northampton Square London, EC1 OHB, UK The Centre for HCl Design, City University, Northampton Square London, EC1 OHB, UKView Profile Authors Info & Claims MULTIMEDIA '98: Proceedings of the sixth ACM international conference on MultimediaSeptember 1998 Pages 29–37https://doi.org/10.1145/290747.290752Published:01 September 1998Publication History 14citation561DownloadsMetricsTotal Citations14Total Downloads561Last 12 Months25Last 6 weeks4 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

We describe a taxonomy of error types that builds on work by Reason (1990) and Hollnagel (1993). The taxonomy uses a faceted schema subdivided into layers. Each layer targets a particular analysis task, and a method is proposed leading the assessor through sets of error types at different levels (e.g. cognitive, social, organizational). This allows the causes of failure to be attributed to one or more error types. The method is illustrated with two case studies of diverse failures. The utility of taxonomy analysis in understanding the reasons for failure and risk assessment is discussed.

A framework for constructing a cognitive model of users' information searching behaviour is described. The motivation for the framework is to create explanatory and predictive theories of information searching to improve the design of information retrieval (IR) systems. The framework proposes a taxonomy of components for process models of the information seeking task, information need types and knowledge sources necessary to support the task. The framework is developed into a preliminary version of a cognitive theory of information searching by the addition of strategies and correspondence rules which predict user behaviour in different task stages according to information need types, facilities provided by the IR system and knowledge held by the user. The theory is evaluated by using claims analysis based on empirical observations of users information retrieval and by a walkthrough of an IR session to investigate how well the theory can account for empirical evidence. Results show that the theory can indicate the expert strategies which should be followed in different task contexts but predictions of actual user behaviour are less accurate. The future possibilities for employing the theoretical model as a tutorial advisor for information retrieval and as an evaluation method for IR systems are reviewed. The role and potential of cognitive theories of user task-action in Information Retrieval and Human Computer Interaction are discussed.

Retrieval, validation, and explanation tools are described for cooperative assistance during requirements engineering and are illustrated by a library system case study. Generic models of applications are reused as templates for modeling and critiquing requirements for new applications. The validation tools depend on a matching process which takes facts describing a new application and retrieves the appropriate generic model from the system library. The algorithms of the matcher, which implement a computational theory of analogical structure matching, are described. A theory of domain knowledge is proposed to define the semantics and composition of generic domain models in the context of requirements engineering. A modeling language and a library of models arranged in families of classes are described. The models represent the basic transaction processing or 'use case' for a class of applications. Critical difference rules are given to distinguish between families and hierarchical levels. Related work and future directions of the domain theory are discussed.

Scenarios have been advocated as a means of improving requirements engineering yet few methods or tools exist to support scenario based RE. The paper reports a method and software assistant tool for scenario based RE that integrates with use case approaches to object oriented development. The method and operation of the tool are illustrated with a financial system case study. Scenarios are used to represent paths of possible behavior through a use case, and these are investigated to elaborate requirements. The method commences by acquisition and modeling of a use case. The use case is then compared with a library of abstract models that represent different application classes. Each model is associated with a set of generic requirements for its class, hence, by identifying the class(es) to which the use case belongs, generic requirements can be reused. Scenario paths are automatically generated from use cases, then exception types are applied to normal event sequences to suggest possible abnormal events resulting from human error. Generic requirements are also attached to exceptions to suggest possible ways of dealing with human error and other types of system failure. Scenarios are validated by rule based frames which detect problematic event patterns. The tool suggests appropriate generic requirements to deal with the problems encountered. The paper concludes with a review of related work and a discussion of the prospects for scenario based RE methods and tools.

Article Free Access Share on Designing effective multimedia presentations Authors: Peter Faraday Centre for HCI Design, City University, London EC1 0HB, UK Centre for HCI Design, City University, London EC1 0HB, UKView Profile , Alistair Sutcliffe Centre for HCI Design, City University, London EC1 0HB, UK Centre for HCI Design, City University, London EC1 0HB, UKView Profile Authors Info & Claims CHI '97: Proceedings of the ACM SIGCHI Conference on Human factors in computing systemsMarch 1997 Pages 272–278https://doi.org/10.1145/258549.258753Published:27 March 1997Publication History 58citation1,810DownloadsMetricsTotal Citations58Total Downloads1,810Last 12 Months87Last 6 weeks25 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my Alerts New Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

The paper reviews studies of attention and recall of expositoryThe results of the studies are taken as a basis to justify the MM presentations, and summarises findings into key guidelines importance of moment by moment design.The problems found in for attentional design.An expert system based design advisor tool attentional design are used to inform a set of guidelines for is then described, which uses the guidelines to analyse MM presentation design.These are then extended to form a method for presentations.analysing MM presentations.

An approach to requirements engineering based on a combination of early prototyping, scenario-based analysis and design rationale is described. Requirements are elicited by presenting users with a prototype-simulation of a prospective design, combined with rationale based techniques for structuring probe questions. Design of analysis sessions and a walkthrough method for requirements elicitation are reported in three layers for linking questions to artefact/scenario demonstrations, follow-up questioning for user-system dependencies and handling user-analyst discourse. An empirical study of the requirements analysis approach is reported. The study used a ship board emergency application. The technique combination approach proved very effective in eliciting requirements but differences in analyst style were an important variable. Recommendations are made for designing and managing requirements capture sessions using scenario-based approaches.

Article Free Access Share on Designing presentation in multimedia interfaces Authors: Alistair Sutcliffe Centre for HCI Design, School of Informatics, City University, Northampton Square, London EC1 0HB, UK Centre for HCI Design, School of Informatics, City University, Northampton Square, London EC1 0HB, UKView Profile , Peter Faraday Centre for HCI Design, School of Informatics, City University, Northampton Square, London EC1 0HB, UK Centre for HCI Design, School of Informatics, City University, Northampton Square, London EC1 0HB, UKView Profile Authors Info & Claims CHI '94: Proceedings of the SIGCHI Conference on Human Factors in Computing SystemsApril 1994 Pages 92–98https://doi.org/10.1145/191666.191710Published:24 April 1994Publication History 16citation1,108DownloadsMetricsTotal Citations16Total Downloads1,108Last 12 Months27Last 6 weeks4 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

The paper presents a theory for reuse of domain knowledge during requirements engineering. The theory includes a set of formal and reusable domain abstractions, a computational analogical reasoning mechanism for their retrieval and tool support to enable both effective requirements modeling and critiquing and guided fact capture prior to retrieval. It was developed as part of the ESPRIT 6353 'Nature' basic research action. The paper argues that the theory has implications for domain modeling as well as domain knowledge reuse during requirements engineering.>

NATURE is a collaborative basic research project on theories underlying requirements engineering funded by the ESPRIT III program of the European communities. Its goals are to develop a theory of knowledge representation that embraces subject, usage and development worlds surrounding the system, including expressive freedoms; a theory of domain engineering that facilitates the identification, acquisition and formalization of domain knowledge as well as similarity-based matching and classifying of software engineering knowledge; and a process engineering theory that promotes context and decision-based control of the development process. These theories are integrated and evaluated in a prototype environment constructed around an extended version of the conceptual modeling language Telos.>

Domain abstraction reuse during requirements engineering is evaluated as a paradigm during use of a research tool. Iterative fact acquisition and abstraction retrieval, supported by example-based explanation of abstractions, are implemented in a prototype known as AIR (adviser for intelligent reuse). Observation of the use of AIRs by inexperienced software engineers reveal the effectiveness of this paradigm despite several problems. These problems are examined so as to identify improvements for future versions of intelligent requirements engineering environments.>

A variety of theoretical approaches to HCI have been proposed in recent years.HCI theories not only have to account predictively for the observed phenomena in interaction but should also be able to demonstrate their utility in improving the design quality of HCI products.The key question to be addressed in this panel is how HCI theories can, and possibly do, influence the design process.Three approaches will be examined.First is the emulation-based theory of design developed by John Carroll and his group at IBM, Yorktown heights.This proposes that designed artifacts (i.e.successful designs and systems) effective embody HCI theory as it is practiced in the field.Design is advanced by generation, evaluation and evolution of artifacts.The second approach, advocated by Richard Young and his colleagues at the Applied Psychology Unit in Cambridge, is to apply cognitive models and architectures to HCI design.This approach will explore how cognitive simulation models can be applied to the design process and the properties required by such theoretical-based models so that they are tractable and usable by designers.The third approach, proposed by John Long and his colleagues at the Ergonomics Unit, University College, London, proposes the development of prescriptive engineering design principles, both substantive and methodological, which in the long term would support practices seeking solutions to the general design problem of HCI.The principles would derive from an engineering conception of HCI, which in the short term supports the development of techniques and methods for effective design.The proponents will discuss how their approaches can support design practice and the ways in which theories are made available to the designer, either as artifact-products, predictive models, prescriptive guidelines and methods, or simply as designers' "tools for thought". THE PANELISTSJohn Carroll is manger of User Interface Theory and design at the IBM Watson Research Centre in Yorktown Height, New York.His research is in the analysis of learning, problem solving and language capacities that underlie endeavour and experience, especially human interaction with computers.

Procedures for integrating task analysis and design of the human computer interface with a structured system development method, Jackson System Development (JSD), are described. Process Structure Diagrams, the major modelling notation of JSD, were used to specify tasks which were analysed to predict cognitive complexity. Task complexity analysis helped allocation and design of human tasks to produce task support specifications. The cognitive dimension of task analysis highlighted the need for task support actions, especially design of information displays to support working memory. Dialogue specification for dialogues and interface displays were based on the task analysis and information requirements. Further analyses addressed the timing constraints on human and computer actions, and derivation of display requirements from task-related information needs. Preliminary evaluation of the method showed the method proved easy to learn even for non HCI specialists.

The relationship between methods for systems development that have originated from work in human-computer interaction (HCI) and in software engineering are examined using a classificatory framework of the system life cycle and the development issues are addressed. Software engineering methods tackle few HCI issues and would benefit from the addition of HCI principles and techniques. It is contended that two groups of HCI methods can be identified, task/organisation and cognitive task analysis; both of which should be integrated with structured system development methods to improve system usability. To encourage their practice, HCI methods need to be integrated with software engineering and to offer more prescriptive design advice.