Procedures for the ergonomic use of desktop computer technology are well documented. The design of computer workstations, positioning of the body, and ergonomic work practices have received a great deal of attention and the relevant ergonomic principles are extensively covered in books, manuals, information guides, and web sites. Despite the proliferation of material, however, there is a wide gap between theory and practice. This thesis investigates the reasons why by comparing the knowledge of practice, derived from four field studies at different times in different kinds of organisation, with the extensive literature on ergonomics that was available at the time. The studies showed that levels of ergonomic knowledge and the priority given to ergonomic computer use were low, irrespective of location, but generally better in public - sector organisations. However, academic staff and post - graduate students reported least awareness of ergonomic principles, were least likely to have received training in ergonomics provided by their organisation, and experienced the highest proportion of physical health symptoms. Most workers did not know whether their organisation had written policies and procedures regarding the ergonomic use of computers. The majority believed ergonomic computer use was not given sufficient priority within their organisation and that they needed to spend more time in training on ergonomics. Most were satisfied with their job ; the work was interesting and there was a variation of tasks. The work environments were generally supportive and the people had adequate job control, although urgencies and deadlines dominated the organisation of work. Overall, the respondents were methodical, thorough, conscientious people who demonstrated generally compliant behaviour in other health promotion areas. It was concluded that the computer users would be more likely than not to apply ergonomic principles to their work if given appropriate information, training and encouragement. The findings highlighted the prevalence of non - ergonomic computer work and provided insights into the nature and extent of the computer - related health problems being experienced. They could have fuelled more commitment to ergonomic computer use within organisations and the development of a workplace culture that took this aspect of work safety seriously and put the proliferating information available into action. / Thesis (Ph.D.)--Medical School, 2004.

Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2000. / Includes bibliographical references.

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references (p.60-65).

Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2000. / Includes bibliographical references.

Proefschrift--Universiteit van Amsterdam, 1967. / Includes bibliography.

Digitized by Kansas State University Libraries

Digitized by Kansas State University Libraries

Call number: LD2668 .R4 1958 A53

Chapter one discusses the rationale for, and the aims of, this study. The design of interactive computer systems is an enterprise quite distinct from the design of other artefacts: design, or inventing a pattern, for interactive computer systems is a matter of design for use.HCI research has recognised the need for a user-centred approach to design, and has correspondingly drawn upon a variety of disciplines. However, the dominance of psychological theory and method has led to the exclusion of a body of applicable findings and methods from disciplines which deal with human interaction, and to a failure to systematically investigate the the links between human interaction and human-computer interaction. Prospectively, conversation analysis provides the resources for design of more natural interactive systems,and represents the possibility of design guidance which avoids the problems inherent in current design guidelines. The methods and findings of conversation analysis, this chapter has proposed, will provide a principled approach both to the investigation of human-computer interaction, and to the design of interactive systems. Within the general aim of investigating the applicability of conversation analysis to HCI, the remainder of this study addresses both the theoretical issues, and illustrates the practical outcomes, in relation to an empirical study of user-system interaction. Chapter two examines in greater detail the perspective of ethnomethodology and the findings of conversation analysis. The expository materials, such as exist in these fields, are recognised as being difficult, especially so for those who may be approaching these topics for the first time, and from other than sociological backgrounds. Accordingly the discussion concentrates upon only their more central assumptions and findings. Chapter one observes that conversation analysis and ethnomethodology have not yet found expression in HCI research largely because of the divergence between their methods and those of psychology. The exact nature of those methods, and their advantages for HCI research, are explored in chapter three. This discussion concerns both the practical methodology adopted in this study, the relationship between experimental and non-experimental investigative methods, and the practical applicability of the methods of conversation analysis in the investigation of human-computer interaction.An empirical study of human-computer interaction is undertaken in chapter four. The examination of videotaped sequences of humancomputer interaction through conversation analytic methods is combined with the findings of conversation analysis, to formulate design guidelines and recommendations. Finally, chapter five attempts to assess the significance of this approach to HCI research and design. The promising route which conversation analysis provides for investigation of user-system interaction, and the possibility that it can inform the design of future interactive systems, is explored.

The work described in this thesis is directed towards the reduction of noise levels in the Hoover Turbopower upright vacuum cleaner. The experimental work embodies a study of such factors as the application of noise source identification techniques, investigation of the noise generating principles for each major source and evaluation of the noise reducing treatments. It was found that the design of the vacuum cleaner had not been optimised from the standpoint of noise emission. Important factors such as noise `windows', isolation of vibration at the source, panel rattle, resonances and critical speeds had not been considered. Therefore, a number of experimentally validated treatments are proposed. Their noise reduction benefit together with material and tooling costs are presented. The solutions to the noise problems were evaluated on a standard Turbopower and the sound power level of the cleaner was reduced from 87.5 dB(A) to 80.4 db(A) at a cost of 93.6 pence per cleaner. The designers' lack of experience in noise reduction was identified as one of the factors for the low priority given to noise during design of the cleaner. Consequently, the fundamentals of acoustics, principles of noise prediction and absorption and guidelines for good acoustical design were collated into a Handbook and circulated at Hoover plc. Mechanical variations during production of the motor and the cleaner were found to be important. These caused a vast spread in the noise levels of the cleaners. Subsequently, the manufacturing processes were briefly studied to identify their source and recommendations for improvement are made. Noise of a product is quality related and a high level of noise is considered to be a bad feature. This project suggested that the noise level be used constructively both as a test on the production line to identify cleaners above a certain noise level and also to promote the product by `designing' the characteristics of the sound so that the appliance is pleasant to the user. This project showed that good noise control principles should be implemented early in the design stage. As yet there are no mandatory noise limits or noise-labelling requirements for household appliances. However, the literature suggests that noise-labelling is likely in the near future and the requirement will be to display the A-weighted sound power level. However, the `noys' scale of perceived noisiness was found more appropriate to the rating of appliance noise both as it is linear and therefore, a sound level that seems twice as loud is twice the value in noys and also takes into consideration the presence of pure tones, which even in the absence of a high noise level can lead to annoyance.