13 resultados para Bulk service queue with vacations to the server

em Aston University Research Archive


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The first part of the thesis compares Roth's method with other methods, in particular the method of separation of variables and the finite cosine transform method, for solving certain elliptic partial differential equations arising in practice. In particular we consider the solution of steady state problems associated with insulated conductors in rectangular slots. Roth's method has two main disadvantages namely the slow rate of con­vergence of the double Fourier series and the restrictive form of the allowable boundary conditions. A combined Roth-separation of variables method is derived to remove the restrictions on the form of the boundary conditions and various Chebyshev approximations are used to try to improve the rate of convergence of the series. All the techniques are then applied to the Neumann problem arising from balanced rectangular windings in a transformer window. Roth's method is then extended to deal with problems other than those resulting from static fields. First we consider a rectangular insulated conductor in a rectangular slot when the current is varying sinusoidally with time. An approximate method is also developed and compared with the exact method.The approximation is then used to consider the problem of an insulated conductor in a slot facing an air gap. We also consider the exact method applied to the determination of the eddy-current loss produced in an isolated rectangular conductor by a transverse magnetic field varying sinusoidally with time. The results obtained using Roth's method are critically compared with those obtained by other authors using different methods. The final part of the thesis investigates further the application of Chebyshdev methods to the solution of elliptic partial differential equations; an area where Chebyshev approximations have rarely been used. A poisson equation with a polynomial term is treated first followed by a slot problem in cylindrical geometry.

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DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY AND INFORMATION SERVICES WITH PRIOR ARRANGEMENT

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With its implications for vaccine discovery, the accurate prediction of T cell epitopes is one of the key aspirations of computational vaccinology. We have developed a robust multivariate statistical method, based on partial least squares, for the quantitative prediction of peptide binding to major histocompatibility complexes (MHC), the principal checkpoint on the antigen presentation pathway. As a service to the immunobiology community, we have made a Perl implementation of the method available via a World Wide Web server. We call this server MHCPred. Access to the server is freely available from the URL: http://www.jenner.ac.uk/MHCPred. We have exemplified our method with a model for peptides binding to the common human MHC molecule HLA-B*3501.

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The European Union institutions represent a complex setting and a specific case of institutional translation. The European Central Bank (ECB) is a particular context as the documents translated belong to the field of economics and, thus, contain many specialised terms and neologisms that pose challenges to translators. This study aims to investigate the translation practices at the ECB, and to analyse their effects on the translated texts. In order to illustrate the way texts are translated at the ECB, the thesis will focus on metaphorical expressions and the conceptual metaphors by which they are sanctioned. Metaphor is often associated with literature and less with specialised texts. However, according to Lakoff and Johnson’s (1980) conceptual metaphor theory, our conceptual system is fundamentally metaphorical in nature and metaphors are pervasive elements of thought and speech. The corpus compiled comprises economic documents translated at the ECB, mainly from English into Romanian. Using corpus analysis, the most salient metaphorical expressions were identified in the source and target texts and explained with reference to the main conceptual metaphors. Translation strategies are discussed on the basis of a comparison of the source and target texts. The text-based analysis is complemented by questionnaires distributed to translators, which give insights into the institution’s translation practices. As translation is an institutional process, translators have to follow certain guidelines and practices; these are discussed with reference to translators’ agency. A gap was identified in the field of institutional translation. The translation process in the EU institutions has been insufficiently explored, especially regarding the new languages of the European Union. By combining the analysis of the institutional practices, the texts produced in the institution and the translators’ work (by the questionnaires distributed to translators), this thesis intends to bring a contribution to institutional translation and metaphor translation, particularly regarding a new EU language, Romanian.

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Objectives: The Competitive Aggressiveness and Anger Scale (CAAS) was developed to measure antecedents of aggression in sport. The critique attacks the CAAS on three points: (1) the definition of aggression in sport adopted, (2) the‘‘one size fits all’’ element in the thinking behind the scale’s development, (3) the nature of the CAAS Anger and Aggressiveness items. The objectives of this response is to address misunderstandings in the critique. Methods: We identified a number of false assumptions that undermine the validity of the critique and attempt to clarify our position with respect to the criticisms made. Results: (1) The CAAS is being criticised for a definition that it did not use. (2) We accepted that the CAAS may not be suitable for everyone in our limitations section and fully accept the limitations of any scale. We have since undertaken a large research project to establish whether the scale is valid across and within specific sports. (3) The fundamental misunderstanding inherent throughout the critique is that the CAAS was designed as a measure of aggression, rather than anger and aggressiveness, rendering the critique of its items redundant. Conclusions: The critique misrepresents the authors of the CAAS and fails to present a coherent argument against its use. We hope to clarify our position here. The evidence to date suggests that the CAAS is a valid measure of anger and aggressiveness in many sports and that these concepts reliably differentiate players who admit unsanctioned aggression from those who do not.

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This essay attempts to ascertain whether a particular meaning of globalisation, and view on its effects and the appropriate response to it, are becoming standardised across academia. To do so, it content-analyses a representative sample of new scholarship, mapping the various approaches of current researchers towards globalisation. The essay shows how globalisation remains a contested concept within studies of higher education, as in many other fields. Rather than globalisation being taken to refer unambiguously to global flows, pressures or trends, its meaning continues to depend on the particular perspective adopted by contemporary researchers. The same conflict is apparent concerning the impacts which are reputed to globalisation and with regard to the appropriate response to globalisation amongst academics and higher education institutions (HEIs) more generally. Perhaps the only apparent point of consensus amongst contemporary researchers is the claim that globalisation affects HEIs, rather than HEIs themselves being implicated in the promotion of globalisation. This position underplays the often important role of HEIs in encouraging cross-border flows and pressures, and global trends such as marketisation.

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A survey of the existing state-of-the-art of turbine blade manufacture highlights two operations that have not been automated namely that of loading of a turbine blade into an encapsulation die, and that of removing a machined blade from the encapsulation block. The automation of blade decapsulation has not been pursued. In order to develop a system to automate the loading of an encapsulation die a prototype mechanical handling robot has been designed together with a computer controlled encapsulation die. The robot has been designed as a mechanical handling robot of cylindrical geometry, suitable for use in a circular work cell. It is the prototype for a production model to be called `The Cybermate'. The prototype robot is mechanically complete but due to unforeseen circumstances the robot control system is not available (the development of the control system did not form a part of this project), hence it has not been possible to fully test and assess the robot mechanical design. Robot loading of the encapsulation die has thus been simulated. The research work with regard to the encapsulation die has focused on the development of computer controlled, hydraulically actuated, location pins. Such pins compensate for the inherent positional inaccuracy of the loading robot and reproduce the dexterity of the human operator. Each pin comprises a miniature hydraulic cylinder, controlled by a standard bidirectional flow control valve. The precision positional control is obtained through pulsing of the valves under software control, with positional feedback from an 8-bit transducer. A test-rig comprising one hydraulic location pin together with an opposing spring loaded pin has demonstrated that such a pin arrangement can be controlled with a repeatability of +/-.00045'. In addition this test-rig has demonstrated that such a pin arrangement can be used to gauge and compensate for the dimensional error of the component held between the pins, by offsetting the pin datum positions to allow for the component error. A gauging repeatability of +/- 0.00015' was demonstrated. This work has led to the design and manufacture of an encapsulation die comprising ten such pins and the associated computer software. All aspects of the control software except blade gauging and positional data storage have been demonstrated. Work is now required to achieve the accuracy of control demonstrated by the single pin test-rig, with each of the ten pins in the encapsulation die. This would allow trials of the complete loading cycle to take place.

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This research explores the role of internal customers in the delivery of external service quality. It will consider any potentially different internal customer types that may exist within the organisation. Additionally, it will explore any potential differences in the dimensions that are used to measure service quality internally and externally. If there are different internal customer types then there may be different dimensions which are used to measure service quality between these types and this will be considered also. The approach adopted given the depth and breadth of understanding required, was an action research case based approach. The research objectives were:(i) To determine the dimensions of internal service quality between internal customer supplier cells. (ii) To determine what variation, if any, there is in the dimension sets between internal customer supplier cells. (iii) To determine any ranking in the dimensions that could exist by internal customer supplier cell type. (iv) To investigate the impact of internal service quality on external service quality over time. The research findings were: (i) The majority of the dimensions used in measuring external service quality were also used internally. There were additions of new dimensions however and some dimensions which were used externally, for internal use, had to be redefined. (ii) Variation in dimension sets were revealed during the research. Four different dimension sets were identified and these were matched with four different types of internal service interaction. (iii) Differences in the ranking of dimensions within each dimension set for each internal customer supplier cell type were confirmed. (iv) Internal service quality was seen to influence external service quality but at a cellular level rather than company level. At the company level, the average internal service quality at the start and finish of the research showed no improvement but external service quality had improved. Further investigation at the cellular level showed that improvements in internal service quality had occurred. Those improvements were found to be with the cells that were closest to the customer.The research implications were found to be: (i) some cells may not be necessary in the delivery of external service quality. (ii) The immediacy of the cell to the external customer and number of interactions into and out of that cell has the greatest effect on external customer satisfaction. (iii) Internal service quality may be driven by the customer affecting those cells at the front end of the business first. This then cascades back to those cells which are less immediate until ultimately the whole organisation shows improvements in internal service quality.

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A study of conveying practice demonstrates that belt conveyors provide a versatile and. much-used method of transporting bulk materials, but a review of belting manufacturers' design procedures shows that belt design and selection rules are often based on experience with all-cotton belts no longer in common use, and are net completely relevant to modern synthetic constructions. In particular, provision of the property "load support", which was not critical with cotton belts, is shown to determine the outcome of most belt selection exercises and lead to gross over specification of other design properties in many cases. The results of an original experimental investigation into this property, carried out to determine the belt and conveyor parameters that affect it, how the major role that belt stiffness plays in its provision; the basis for a belt stiffness test relevant to service conditions is given. A proposal for a more rational method of specifying load support data results from the work, but correlation of the test results with service performance is necessary before the absolute toad support capability required from a belt for given working conditions can be quantified. A study to attain this correlation is the major proposal for future work resulting from the present investigation, but a full review of the literature on conveyor design and a study of present practice within the belting industry demonstrate other, less critical, factors that could profitably be investigated. It is suggested that the most suitable method of studying these would be a rational data collection system to provide information on various facets of belt service behaviour; a basis for such a system is proposed. In addition to the work above, proposals for simplifying the present belt selection methods are made and a strain transducer suitable for use in future experimental investigations is developed.

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Price increases seem to be an adequate way to improve the earnings of companies. This fact becomes especially crucial because of increased price competition in many markets. Price increases might lead to negative customer reactions, such as a lower perceived utility or a lower loyalty intention. Therefore, the question for managers remains how prices can be increased without losing customers. Results of our experimental study suggest that customers of energy suppliers rate the perceived utility of the offer relatively better when the price increase is combined with an additional modification of the product or accompanied by a new service. It becomes clear that intensifying service relations can offset the negative effects of price increases.

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Models are central tools for modern scientists and decision makers, and there are many existing frameworks to support their creation, execution and composition. Many frameworks are based on proprietary interfaces, and do not lend themselves to the integration of models from diverse disciplines. Web based systems, or systems based on web services, such as Taverna and Kepler, allow composition of models based on standard web service technologies. At the same time the Open Geospatial Consortium has been developing their own service stack, which includes the Web Processing Service, designed to facilitate the executing of geospatial processing - including complex environmental models. The current Open Geospatial Consortium service stack employs Extensible Markup Language as a default data exchange standard, and widely-used encodings such as JavaScript Object Notation can often only be used when incorporated with Extensible Markup Language. Similarly, no successful engagement of the Web Processing Service standard with the well-supported technologies of Simple Object Access Protocol and Web Services Description Language has been seen. In this paper we propose a pure Simple Object Access Protocol/Web Services Description Language processing service which addresses some of the issues with the Web Processing Service specication and brings us closer to achieving a degree of interoperability between geospatial models, and thus realising the vision of a useful 'model web'.

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This study investigates the effects of brand-specific leadership on employees' brand-aligned service recovery performance (SRP). In order to do so, we empirically test a conceptual model of relationships between brand-specific transformational leadership (TFL) and transactional leadership (TRL), trust in leader and in corporate brand, brand identification, and SRP from employees' perspectives. It is the first study to incorporate trust in corporate brand into the framework. Results from a study of 246 customer-contact employees show that brand-specific TFL has a positive impact on all variables studied, while brand-specific TRL is ineffective in fostering brand-building behaviours. More specifically, brand-specific TFL's effects on employee SRP are mediated by trust in the leader, trust in the corporate brand, and brand identification. Implications and future research directions are discussed. © 2013 Copyright Taylor & Francis.