7 resultados para Repertory grid technique

em Aston University Research Archive


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The research was instigated by the Civil Aviation Authority (CAA) to examine the implications for air traffic controllers' (ATCO) job satisfaction of the possible introduction of systems incorporating computer-assisted decision making. Additional research objectives were to assess the possible costs of reductions in ATCO job satisfaction, and to recommend appropriate task allocation between ATCOs and computer for future systems design (Chapter 1). Following a review of the literature (Chapter 2) it is argued that existing approaches to systems and job design do not allow for a sufficiently early consideration of employee needs and satisfactions in the design of complex systems. The present research develops a methodology for assessing affective reactions to an existing system as a basis for making reommendations for future systems design (Chapter 3). The method required analysis of job content using two techniques: (a) task analysis (Chapter 4.1) and (b) the Job Diagnostic Survey (JDS). ATCOs' affective reactions to the several operational positions on which they work were investigated at three levels of detail: (a) Reactions to positions, obtained by ranking techniques (Chapter 4.2); (b) Reactions to job characteristics, obtained by use of JDS (Chapter 4.3); and (c) Reactions to tasks, obtained by use of Repertory Grid technique (Chapter 4.4). The conclusion is drawn that ATCOs' motivation and satisfaction is greatly dependent on the presence of challenge, often through tasks requiring the use of decision making and other cognitive skills. Results suggest that the introduction of systems incorporating computer-assisted decision making might result in financial penalties for the CAA and significant reductions in job satisfaction for ATCOs. General recommendations are made for allocation of tasks in future systems design (Chapter 5).

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A multi-variate descriptive model of environmental and nature conservation attitudes and values is proposed and empirically supported. A mapping sentence is developed out of analysis of data from a series of Repertory Grid interviews addressing conservation employees' attitudes towards their profession's activities. The research is carried out within the meta-theoretical framework of Facet Theory. A mapping sentence is developed consisting of 9 facets. From the mapping sentence 3 questionnaires were constructed viewing the selective orientations towards environmental concern. A mapping sentence and facet model is developed for each study. Once the internal structure of this model had been established using Similarity Structure Analysis, the elements of the facets are subjected to Partial Order Scalogram Analysis with base coordinates. A questionnaire was statistically analysed to assess the relationship between facet elements and 4 measures of attitudes towards, and involvement with, conservation. This enabled the comparison of the relative strengths of attitudes associated with each facet element and each measure of conservation attitude. In general, the relationship between the social value of conservation and involvement pledges to conservation were monotonic; perceived importance of a conservation issue appearing predictive of personal involvement. Furthermore, the elements of the life area and scale facets were differentially related to attitude measures. The multi-variate descriptive model of environmental conservation values and attitudes is discussed in relation to its implications for psychological research into environmental concern and for environmental and nature conservation.

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This thesis reports the findings of three studies examining relationship status and identity construction in the talk of heterosexual women, from a feminist and social constructionist perspective. Semi-structured interviews were conducted with 12 women in study 1 and 13 women for study 2, between the ages of twenty and eighty-seven, discussing their experiences of relationships. All interviews were transcribed and analysed using discourse analysis, by hand and using the Nudist 6 program. The resulting themes create distinct age-related marital status expectations. Unmarried women were aware they had to marry by a ‘certain age’ or face a ‘lonely spinsterhood’. Through marriage women gained a socially accepted position associated with responsibility for others, self-sacrifice, a home-focused lifestyle and relational identification. Divorce was constructed as the consequence of personal faults and poor relationship care, reassuring the married of their own control over their status. Older unmarried women were constructed as deviant and pitiable, occupying social purgatory as a result of transgressing these valued conventions. Study 3 used repertory grid tasks, with 33 women, analysing transcripts and notes alongside numerical data using Web Grid II internet analysis tool, to produce principle components maps demonstrating the relationships between relationship terms and statuses. This study illuminated the consistency with which women of different ages and status saw marriage as their ideal living situation and outlined the domestic responsibilities associated. Spinsters and single-again women were defined primarily by their lack of marriage and by loneliness. This highlighted the devalued position of older unmarried women. The results of these studies indicated a consistent set of age-related expectations of relationship status, acknowledged by women and reinforced by their families and friends, which render many unmarried women deviant and fail to acknowledge the potential variety of women’s ways of living.

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Previous research has indicated that the majority of the UK dentate population suffers from dental disease. This problem was examined in terms of the supply of, and demand for, dental treatment: how might the uptake of dental services be increased and dental health improved? The target population for the main survey was adolescents among whom demand for dental treatment has decreased. In 524 adolescents surveyed, fear of pain was the major deterrent to regular dental visits. The theoretical literature was explored for illuminating and practical approaches to the problem. The theory of reasoned action developed by Fishbein seemed the most promising. This theory was tested and validated on the adolescent sample identifying clear differences between regular and irregular dental attenders which could be usefully exploited by dental health education. A repertory grid analysis study further illuminated perceptions of dental treatment. A survey of a random sample of 716 dentists revealed that most dentists were in favour of delegating work to auxiliary help but few could do so. Auxiliary help would increase supply of services: data revealed an encouraging trend for younger dentists to be more in favour of delegation than older dentists. A survey was carried out of computer systems available for dentists suggesting that this might reduce the need for clerical assistance but would not ususally affect the supply of treatment. However in some dental practices computerisation might increase demand. For example a personalised reminder was developed and evaluated in a controlled study of 938 appointments demonstrating an uptake in dental services. Conclusions are that demand for treatment can be increased in various ways especially by teaching dentists' behavioural strategies to deal with fear and pain. Various recommendations on this are made. If demand were to outstrip supply increased delegation to auxiliary help could provide a viable way of increasing supply.

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The burgeoning research into altruism and helping behaviour has examined the effect of many variables that enhance or inhibit helpfulness, but little attention has been given to the influence of culture. In the present research, data on various aspects of helping behaviour were collected in both the UK and the Sudan so that the importance of cultural influences could be investigated. In addition this research also tested the validity of current models of helping. In a repertory grid study, urgency and cost emerged as the main constructs people in the two countries use to distinguish between various helpful situations. A laboratory experiment designed to test existing models of intervention behaviour found significant main effects of country, group, size, cost and urgency; and a group size/urgency interaction. Subjects in the Sudan intervened faster than subjects in the UK; lone subjects intervened faster than subjects in small and large groups; subjects in low cost intervened faster than subjects in high cost conditions; and subjects in high urgency intervened faster than subjects in low urgency conditions. Group size effect was stronger in low than in high urgency conditions. Two field studies further investigated the effect of urgency and cost in urban-nonurban context. Significant main effects of urgency and cost were found in cities but not in towns; and people in cities were less helpful than people in towns. A questionnaire survey found that in both countries there were significant urban-nonurban differences in the incidence of reported social contacts and exchange of helpful acts between acquaintances, neighbours and strangers. However, there were no urban-nonurban differences between relatives and close friends. Finally, attitudes to altruism and helpfulness did not differ between the two countries or between urban and nonurban residents. The results highlight the need to incorporate urgency and cultural variables in theoretical models of helping behaviour.

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The open content creation process has proven itself to be a powerful and influential way of developing text-based content, as demonstrated by the success of Wikipedia and related sites. Distributed individuals independently edit, revise, or refine content, thereby creating knowledge artifacts of considerable breadth and quality. Our study explores the mechanisms that control and guide the content creation process and develops an understanding of open content governance. The repertory grid method is employed to systematically capture the experiences of individuals involved in the open content creation process and to determine the relative importance of the diverse control and guiding mechanisms. Our findings illustrate the important control and guiding mechanisms and highlight the multifaceted nature of open content governance. A range of governance mechanisms is discussed with regard to the varied levels of formality, the different loci of authority, and the diverse interaction environments involved. Limitations and opportunities for future research are provided.

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The modern grid system or the smart grid is likely to be populated with multiple distributed energy sources, e.g. wind power, PV power, Plug-in Electric Vehicle (PEV). It will also include a variety of linear and nonlinear loads. The intermittent nature of renewable energies like PV, wind turbine and increased penetration of Electric Vehicle (EV) makes the stable operation of utility grid system challenging. In order to ensure a stable operation of the utility grid system and to support smart grid functionalities such as, fault ride-through, frequency response, reactive power support, and mitigation of power quality issues, an energy storage system (ESS) could play an important role. A fast acting bidirectional energy storage system which can rapidly provide and absorb power and/or VARs for a sufficient time is a potentially valuable tool to support this functionality. Battery energy storage systems (BESS) are one of a range suitable energy storage system because it can provide and absorb power for sufficient time as well as able to respond reasonably fast. Conventional BESS already exist on the grid system are made up primarily of new batteries. The cost of these batteries can be high which makes most BESS an expensive solution. In order to assist moving towards a low carbon economy and to reduce battery cost this work aims to research the opportunities for the re-use of batteries after their primary use in low and ultra-low carbon vehicles (EV/HEV) on the electricity grid system. This research aims to develop a new generation of second life battery energy storage systems (SLBESS) which could interface to the low/medium voltage network to provide necessary grid support in a reliable and in cost-effective manner. The reliability/performance of these batteries is not clear, but is almost certainly worse than a new battery. Manufacturers indicate that a mixture of gradual degradation and sudden failure are both possible and failure mechanisms are likely to be related to how hard the batteries were driven inside the vehicle. There are several figures from a number of sources including the DECC (Department of Energy and Climate Control) and Arup and Cenex reports indicate anything from 70,000 to 2.6 million electric and hybrid vehicles on the road by 2020. Once the vehicle battery has degraded to around 70-80% of its capacity it is considered to be at the end of its first life application. This leaves capacity available for a second life at a much cheaper cost than a new BESS Assuming a battery capability of around 5-18kWhr (MHEV 5kWh - BEV 18kWh battery) and approximate 10 year life span, this equates to a projection of battery storage capability available for second life of >1GWhrs by 2025. Moreover, each vehicle manufacturer has different specifications for battery chemistry, number and arrangement of battery cells, capacity, voltage, size etc. To enable research and investment in this area and to maximize the remaining life of these batteries, one of the design challenges is to combine these hybrid batteries into a grid-tie converter where their different performance characteristics, and parameter variation can be catered for and a hot swapping mechanism is available so that as a battery ends it second life, it can be replaced without affecting the overall system operation. This integration of either single types of batteries with vastly different performance capability or a hybrid battery system to a grid-tie 3 energy storage system is different to currently existing work on battery energy storage systems (BESS) which deals with a single type of battery with common characteristics. This thesis addresses and solves the power electronic design challenges in integrating second life hybrid batteries into a grid-tie energy storage unit for the first time. This study details a suitable multi-modular power electronic converter and its various switching strategies which can integrate widely different batteries to a grid-tie inverter irrespective of their characteristics, voltage levels and reliability. The proposed converter provides a high efficiency, enhanced control flexibility and has the capability to operate in different operational modes from the input to output. Designing an appropriate control system for this kind of hybrid battery storage system is also important because of the variation of battery types, differences in characteristics and different levels of degradations. This thesis proposes a generalised distributed power sharing strategy based on weighting function aims to optimally use a set of hybrid batteries according to their relative characteristics while providing the necessary grid support by distributing the power between the batteries. The strategy is adaptive in nature and varies as the individual battery characteristics change in real time as a result of degradation for example. A suitable bidirectional distributed control strategy or a module independent control technique has been developed corresponding to each mode of operation of the proposed modular converter. Stability is an important consideration in control of all power converters and as such this thesis investigates the control stability of the multi-modular converter in detailed. Many controllers use PI/PID based techniques with fixed control parameters. However, this is not found to be suitable from a stability point-of-view. Issues of control stability using this controller type under one of the operating modes has led to the development of an alternative adaptive and nonlinear Lyapunov based control for the modular power converter. Finally, a detailed simulation and experimental validation of the proposed power converter operation, power sharing strategy, proposed control structures and control stability issue have been undertaken using a grid connected laboratory based multi-modular hybrid battery energy storage system prototype. The experimental validation has demonstrated the feasibility of this new energy storage system operation for use in future grid applications.