This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A. (2001) Usability evaluation. In W. Karwowski (ed.) Encyclopedia of Human Factors and Ergonomics, London: Taylor and Francis. Introduction: Usability is a measure of interface quality that refers to the effectiveness, efficiency and satisfaction with which users can perform tasks with a tool. Evaluating usability is now considered an essential part of the system development process and a variety of methods and have been developed to support the human factors professional in this work.

This item is not the definitive copy. Please use the following citation when referencing this material: McKnight, C., Dillon, A. and Richardson, J. (1992) Hypermedia. In A. Kent (Ed.) Encyclopedia of Library and Information Science, Vol. 50, New York: Marcel Dekker, 226-255. Overview: The field of hypertext/hypermedia has mushroomed so much in the last five years that an article such as this cannot hope to be all-embracing. Rather, what we will do is provide a perspective on hypertext/hypermedia while offering guidance to the published literature. The perspective we give is essentially user-centred since we believe that ultimately it is user issues which will determine the success or failure of any technology. We begin with a brief introduction and history then draw together some of the relevant research which has a bearing on hypertext/hypermedia usability. Some of this research has been conducted specifically in the field of hypertext but some general human-computer interaction research also needs to be considered. We look briefly at some of the issues involved in creating hypertexts and also at some of the claims made for hypertext. Finally, we attempt to see what the future holds for hypertext and offer a list of further reading.

This is a preprint version of Dillon, A. (2000) Group Dynamics Meet Cognition: applying socio-technical concepts in the design of information systems. In Coakes, E., Willis, D. and Lloyd-Jones, R. (eds.) The New SocioTech: Graffiti on the Long Wall, Springer Verlag Series on CSCW, London: Springer, 119-125. Chapter overview: Socio-Technical Systems Theory (STST) has been widely mentioned and applied in the domain of information systems implementation (see e.g. Eason [1], Mumford [2]). Dillon and Morris [3] argue that the term STST is now generally applied to many user-centered orientations to design and implementation. Unlike the pragmatism of usability engineering which aims to support the design of technologies that are compatible with users' abilities and needs[4], STST posits underlying drives and motivations to use tools that supersede concerns with effectiveness and efficiency alone. In the present chapter, STST is re-examined for relevance to contemporary software design practices. Specifically, the unconscious drives to gain control and enhancement through one's work are seemingly at odds with a strictly cognitive approach to interaction that dominates studies of human-computer interaction. STST is here critically assessed in the light of what is now known about user acceptance of new information technologies. Emerging ISO-backed usability standards are in turn critically evaluated in the light of STST's richer analysis to identify weaknesses in the current usability engineering approach to design and implementation. Reconciling the psychodynamic and the cognitive in a manner that enables pragmatic application of STST in design is gained through the formulation of operationalised measures of the forces shaping acceptance.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A. (2001) User Acceptance of Information Technology. In: W. Karwowski (ed). Encyclopedia of Human Factors and Ergonomics. London: Taylor and Francis. Introduction: Despite significant investments in information technology in developed nations over recent decades, concern exists over the extent to which such expenditures have produced the intended benefits. At least part of this concern is based around the issue of whether any information technology is accepted by its intended users. Human factors professionals are interested in understanding the determinants of acceptance and ensuring new designs are built and implemented so as to minimize resistance. This concern has extended the traditional ergonomic concern with usability, or ability to use, to cover acceptance, or willingness to use.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A., Sweeney, M. and Maguire, M. (1993) A survey of usability evaluation practices and requirements in the European IT industry. In. J. Alty, S. Guest and D. Diaper (eds.) HCI'93. People and Computers VII. Cambridge: Cambridge University Press. Abstract: The present paper reports on a survey of current practices in usability engineering and requirements for support within European I.T. organisations. Responses were obtained from 84 individuals working in nine European countries. The data were analysed in terms of four themes: respondents' background, their interpretation and appreciation of the concept of usability, current practice with regard to usability evaluation, problems and requirements for support in conducting usability evaluation. Results suggest widespread awareness but only superficial application of Human Factors methods in Industry.

This item is not the definitive copy. Please use the following citation when referencing this material: McKnight, C., Dillon, A., and Richardson, J. (1990) A comparison of linear and hypertext formats in information retrieval. In R. McAleese and C. Green, Hypertext: state of the art, Oxford: Intellect, 10-19. Abstract An exploratory study is described in which the same text was presented to subjects in one of four formats, of which two were hypertext (TIES and Hypercard) and two were linear (Word Processor and paper). Subjects were required to use the text to answer 12 questions. Measurement was made of their time and accuracy and their movement through the document was recorded, in addition to a variety of subjective data being collected. Although there was no significant difference between conditions for task completion time, subjects performed more accurately with linear formats. The implications of these findings and the other data collected are discussed.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A., Sweeney, M., Herring, V., John, P. and Fallon, E. (1988) The psychology of designer style. The Alvey Conference 1988. DTI/IED Publications, 323-327. 1. INTRODUCTION: Underlying the notion of style is a basic premise that all designers are not the same and that the manner in which any designer tackles a problem and proposes a solution may be qualitatively different from other designers. If this is shown to be the case and the concept of designer style can be meaningfully discussed then any model of the process of design should allow for such variation at the level of the group or individual. This basically describes the starting point of the HUSAT team's investigation of the concept.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A., Richardson, J. and McKnight, C. (1990) Navigation in Hypertext: a critical review of the concept. In D.Diaper, D.Gilmore, G.Cockton and B.Shackel (eds.) Human-Computer Interaction-INTERACT'90. North Holland: Amsterdam, 587-592. Abstract: With the advent of hypertext it has become widely accepted that the departure from the so-called "linear" structure of paper increases the likelihood of readers or users becoming lost. In this paper we will discuss this aspect of hypertext in terms of its validity, the lessons to be learned from the psychology of navigation and the applicability of the navigation metaphor to the hypertext domain.

This item is not the definitive copy. Please use the following citation when referencing this material: Dillon, A. (2001) Usability Issues in Hypermedia. In: W. Karwowski (ed). Encyclopedia of Human Factors and Ergonomics. London: Taylor and Francis. 1. Introduction: Hypermedia is a general term used to describe the presentation of graphical, textual, audio and video information in nodes (chunks) that can be linked together and accessed in a manner determined by the immediate interests of the user. Originating as an idea for mechanized information access and organization that better reflected the natural workings of the human mind by Vannevar Bush (1945), the potential of the computer to provide the best means of supporting hypermedia was recognized early on by thinkers such as Ted Nelson and Doug Engelbart (for a historical overview see Conklin, 1987). The move toward hypermedia-based digital documents holds with it the promise of user-controlled, immediate access to the world of published information and stored data. While originally a specialist application domain, in the last few years the World Wide Web has brought to everyoneâ s desktop the power and problems of hypermedia interaction. Yet from the outset, human factors researchers have noted a range of user issues that prevent the simple transition from analog to digital resources

Seguint una concepció clàssica de la Intel•ligència Artificial (aquella que es posava com horitzó una definició dels mecanismes cognitius i la seva implementació en computadors), aquesta tesi s'endinsa en el problema de l'organització del coneixement. En especial, es posa atenció a la memòria semàntica i el coneixement lingüístic, intentant esbrinar de quina forma emergeixen les relacions semàntiques entre paraules. Per assolir aquests objectius es recorre a tres fonts principals: la utilització de dades empíriques provinents de la psicolingüística i la neuropsicologia; l'ús de la metodologia de sistemes complexes (física estadística) per la construcció de models i simulació de dinàmiques; i finalment l'aprofitament de les tecnologies al nostre abast tant per l'obtenció de noves dades (Internet) com una capacitat d'emmagatzemament suficient i velocitat de processament per al tractament de dades massives. D'aquest punt de vista arrelat en la Ciència Cognitiva en poden sorgir aplicacions fortament vinculades a problemes vigents en l'àmbit de Ciències de la Computació, com són l'extracció d'informació no supervisada, l'enriquiment de bases de dades i recursos lingüístics electrònics (Wikipedia, WordNet, etc.) i la millora de sistemes de consulta (query-based systems). Al Capítol 2 s'estableixen les bases metodològiques que han servit per construir la resta del treball. El Capítol 3 es dedica a aclarir (i) quina mena de dades s'han emprat (i s'empren) en l'estudi a gran escala del llenguatge i els fenòmens cognitius que l'envolten; i (ii) es revisen els treballs més destacables que s'han fet fins al moment actual al voltant del llenguatge i la cognició. Al Capítol 4 s'introdueix el Random Inheritance Model, que representa un intent per comprendre com emergeixen la similitud semàntica entre paraules i les categories semàntiques. Els resultats es comparen amb dades empíriques basades en les respostes de subjectes humans. Al Capítol 5 presentem un model de degradació semàntica que emula processos neurodegeneratius i prediu acuradament, a nivell qualitatiu, les observacions experimentals amb malalts d'Alzheimer que s'han fet en l'àmbit de la neuropsicologia. En aquests processos degeneratius convergeixen interessos multidisciplinars, que van de la mateixa cognició al fenomen de percolació en física estadística. El Capítol 6 queda finalment dedicat a una reflexió global d'aquesta memòria. / Following a classical conception of Artificial Intelligence (one that aims a definition of cognitive mechanisms and their implementation in computers), this thesis explores the problem of knowledge organization. In particular, it draws attention to the linguistic and semantic memory, trying to find out how semantic relations emerge between words. To achieve these objectives, we rely on three main sources: use of empirical data from psycholinguistics and neuropsychology; the use of complex systems (statistical physics) methodology to build and simulate dynamic models; and finally the utilization of technologies at our disposal both for obtaining new data (Internet) as well as sufficient storage capacity and processing speed for massive data manipulation. From this point of view, rooted in Cognitive Science, many applications may arise, some of them strongly linked to current problems in the field of Computer Science, such as unsupervised information extraction, enrichment of databases and language electronic resources (Wikipedia, WordNet, etc.). and improve consultation systems (query-based systems). In Chapter 2 the methodologies that have helped build the rest of the work are established. Chapter 3 is devoted to clarify (i) the kind of data that have been used in the large-scale study of language and cognitive phenomena around it, and (ii) review some of the major contributions to the date about language and cognition. In Chapter 4 the Random Inheritance Model is introduced, which represents an attempt to understand how does semantic similarity between words and semantic categories emerge. Results are compared with empirical data obtained from responses with human subjects. In Chapter 5 we present a model of semantic degradation which emulates neurodegenerative processes, and predicts experimental observations from Alzheimer's Disease patients in the field of neuropsychology. In the study of such degenerative processes different multidisciplinary interests converge, ranging from cognition itself to percolation theory in statistical physics. Chapter 6 is finally devoted to a global reflection of this memory.