No description available.

No description available.

No description available.

No description available.

The research is primarily concerned with the investigation of factors relating to the way that naive computer users build up their internal representations or cognitive models of the computer systems they use. Particular emphasis is placed on investigating the roles of aptitudes, attitudes and personality in the development of such models. The research also became directed towards investigating Lhe implications of advanced technology for use by members of the general public. The research is split up into the following studies: 1) A study of naive computer users investigating the way in which they responded to a simulated rail information system, in comparison with their response to its manual counterpart. The problem solving heuristics used by the subjects were investigated as well as the ways that computers were perceived in relation to other objects. 2) Two studies were carried out to investigate the roles of attitudes and aptitudes for success in an introductory computing course in the BASIC language. 3) The progress of one student undergoing the computing course was investigated closely with a view to finding out how the learning process was taking place. 4) A field study was performed in a Regional Electricity Board with the aim of identifying the attitudes towards computers of non-expert users. The questionnaire survey technique used was also intended to identify the sources of difficulty that users of computers reported and to define the information sources available to them. 5) A study was performed looking at students who had performed well on an introductory computing course and others who had performed poorly. Differences in attitude and personality between these two gruups werc investigated with particular reference to a hypothesised 'machine-oriented' personality type. 6) A final questionnaire survey was performed looking at attitudes towards machinery, computers in general and more specifically the use of automated cash-dispensers of the type used in banks. From all these studies the theoretical basis of the 'machine-orientated' personality type was developed. The implications of these issues for interface design is discussed, along with recommendations for future research in this area.

Since 1976 the author has worked with L. M. Ericsson Ab of Stockholm, Sweden, providing ergonomics advice relating to the design of operator positions for stored program controlled telephone exchanges manufactured by this company. The research was I performed in three phases: a literature review, preliminary experiments to evaluate alternative equipment designs and finally a series of trials of the prototype under simulated call conditions. The basis of the new operator position is tie provision of a computer terminal, consisting of a datascreen or video display unit (vdu) and keyboard at each operator desk. These terminals enable the operator to enter call details into memory stores from which they can be 'read' by the computer, displayed at any operator position or routed to the charging system. By eliminating many repetitious and error prone number entries, by abolishing pager handling tasks completely and by automating certain call handling operations a more efficient and effective service can be provided to subscribers. The literature review report, produced on completion of Phase I, summarised the ergonomics research relating to datascreens, keyboards, dialogues, workstations and environmental factors. As a result of the review the author was able to produce detailed ergonomics recommendations for many parts of the system. Phase II consisted of a programme of experiments to provide the data required to resolve design conflicts remaining at the conclusion of Phase I. In successive stages a panel of experts reduced the potential number of datascreen designs to practicable numbers for controlled experiments. These datascreens, filters and screen treatments were systematically compared in experiments and a suitable design was selected. In Phase III an experiment was conducted to evaluate the entire operator position under simulated call handling conditions. In addition to collecting objective measures of call handling speed and accuracy, the experiments also enabled visual fatigue to be assessed and call handling equipment and procedures to be judged by experienced operators under' reasonably realistic conditions.

This thesis suggests that there is a problem with technology transfer in crop production. The nature of the problem and the mechanisms available to the agricultural research sector for solving it are examined. As a consequence it is argued that Decision Support Systems (DSS) technology is an extremely useful mechanism for encapsulating and delivering scientific knowledge to the industry. The thesis then poses the question of why this technology is not currently being taken up by farmers and farm consultants, hypothesising that the current lack of user involvement in design is a major contributing factor. The hypothesis is supported by a survey of DSS development and use in agriculture and it is concluded that a user-centred design (UCD) approach is important to the successful adoption of these systems by the industry. The thesis then asks what methods the agricultural DSS developers should employ to ensure a user-centred design approach. It is suggested that it is not sufficient merely to point DSS producers in the direction of user centred design but to furnish them with adequate methods and tools to achieve this goal, bearing in mind their specific requirements and limitations and the nature of the decision support task. A review of currently available methods reveals that none of the standard methods meets this requirement and that a new approach is therefore needed. An approach supported by work from management science is introduced. This approach identifies the user's questions to the system as a means of defining its function and features. Its use in the context of workshops is developed into a user centred design method to meet all of the requirements for the designer stakeholders. The question approach is also used as the basis of ä method for identifying DSS interface requirements and collating design solutions. Both methods are presented as mechanisms for improving the acceptance of DSS in the sector. The document concludes by discussing the contribution made by the thesis to its originating disciplines and looks forward to the future of DSS technology in crop production.

No description available.

The aim was to formulate ergonomics criteria to assist in the design and evaluation of various commonly used packages so that they are well adapted to the needs, capabilities and limitations of consumers. The consumers used in the study included male and female able-bodied subjects, some of whom were elderly; and the disabled, who suffered from arthritis, Parkinson's disease, cerebral palsy, multiple sclerosis, or one-handed function (hemiplegics or amputees). The design criteria took the form of normative data. These were derived, by experiment, with subjects handling specially designed apparatus which closely simulated the characteristics of real packages. The norms were the torques and forces that the weak, average and strong subjects could exert on a range of packages. The norms were related to the breaking torques and breaking forces of packages found in the market place. It was shown that many of these packages require opening torques and forces which are well beyond the capabilities of the weaker sections of the sample. New methods for representing the torques which people can exert were derived, involving the calculation of ratios of centiles between and within groups for comfortable and maximum exertions of torque. It is suggested that this method, which has considerable promise, be further validated in future studies involving not only the description of forces and torques, but also that of the reaches, carrying and lifting capacity, the articulation, pushing and pulling capacity, and physical endurance of human subjects. The promise lies in the short-hand derivation of the capabilities of weaker segments of the population, who are difficult to obtain in large numbers, from studies involving small samples from the fit and able population.

This thesis considers the application of ergonomics in Industrially Developing Countries (IDCs) with a particular focus on rural subsistence agriculture in Ghana. The thesis had two aims, firstly to identify the need for ergonorMcs to be incorporated into international development projects. A survey of the causes and incidence of illhealth in subsistence fanning was undertaken A high incidence of occupational disorders was recorded with injuries Erom. handtools and lower back pain being endemic. This survey was followed by a checklist analysis and Participatory Rural Appraisal of agroprocessing. Ergonomics issues were identified in many agroprocessing activities. These included poor posture, repetitive motions, manual handling, and stressful work environments. Inappropriate technology transfer was widespread. Farmers behaviour when working in high ambient temperatures was investigated in the field. Whilst methodological problems were encountered and discussed, heat stress was considered a potential problem that deemed further investigation. From the surveys and field investigation, ergonorMcs problems in human work in rural subsistence agriculture were identified and a need for ergonotMcs to be incorporated into development projects was demonstrated. In the light of this, the second aim of the thesis was addressed, investigating the appropriateness of tools, methods and standards for use in IDCs with an ergonomics tool kit being developed. Following on from the field investigation into working in the heat, stratergies for assessing heat stress in tropical agriculture were assessedin terms of their validity and usability. In a simulated tropical agricultural task heat stress standards (ISO 7243 and ISO 7933) were found to be valid if over protective. It can be anticipated that the ISO 7243 can be easily used in IDCs. The usability of ISO 7933 however was questioned. As the standards failed to accommodate for solar load, solar radiation and its effects on the human thermoregulatory system were considered. Six subjects performed a step test in outdoor conditions with a solar load, repeating this in similar conditions in a thermal chamber with no solar load. The difference in sweat loss between the conditions was attributed to the increased load from solar radiation. In the conditions measured, the radiation incident on the human thermoregulatory system was 82W/M 2. Two existing models for solar radiation were validated. Subjective and objective ergonomics tools were assembled in a tool kit that was used on an ad hoc basis in the field in Ghana. A pragmatic approach to the usability of the tool kit was adopted. Drawing on practical experiences and expert analysis, it was found that simple, reliable, robust and easy to maintain equipment was most appropriate and usable in the field. Subjective rating scales proved to be difficult to use and were unreliable. Participatory rural appraisal methods were found to be simple, rapid and well suited to ergonomics research in tropical agriculture. Practical implications from the research in Ghana were discussed and recommendations made. The thesis concluded that there is a need for ergonomics interventions in IDCs with the ergonomics tool kit being generally acceptable for use in this field. The thesis concluded that there is a need for ergonormcs and that the tools, methods and standards considered were found to be generally usable, although the approach often required adapting to local circumstances whilst maintaining scientific integrity.