912 resultados para chaotic and hyperchaotic rossler systems
Resumo:
The adoption of DRG coding may be seen as a central feature of the mechanisms of the health reforms in New Zealand. This paper presents a story of the use of DRG coding by describing the experience of one major health provider. The conventional literature portrays casemix accounting and medical coding systems as rational techniques for the collection and provision of information for management and contracting decisions/negotiations. Presents a different perspective on the implications and effects of the adoption of DRG technology, in particular the part played by DRG coding technology as a part of a casemix system is explicated from an actor network theory perspective. Medical coding and the DRG methodology will be argued to represent ``black boxes''. Such technological ``knowledge objects'' provide strong points in the networks which are so important to the processes of change in contemporary organisations.
Advanced UV inscribed fibre grating structures and applications in optical sensing and laser systems
Resumo:
This thesis presents detailed investigation of UV inscribed fibre grating based devices and novel developments in the applications of such devices in optical sensing and fibre laser systems. The major contribution of this PhD programme includes the systematic study on fabrication, spectral characteristics and applications of different types of UV written in-fibre gratings such as Type I and IA Fibre Bragg Gratings (FBGs), Chirped Fibre Bragg Gratings (CFBGs) and Tilted Fibre Gratings (TFGs) with small, large and 45º tilted structures inscribed in normal silica fibre. Three fabrication techniques including holographic, phase-mask and blank beam exposure scanning, which were employed to fabricate a range of gratings in standard single mode fibre, are fully discussed. The thesis reports the creation of smart structures with self-sensing capability by embedding FBG-array sensors in Al matrix composite. In another part of this study, we have demonstrated the particular significant improvements made in sensitising standard FBGs to the chemical surrounding medium by inducing microstructure to the grating by femtosecond (fs) patterning assisted chemical etching technique. Also, a major work is presented for the investigation on the structures, inscription methods and spectral Polarisation Dependent Loss (PDL) and thermal characteristics of different angle TFGs. Finally, a very novel application in realising stable single polarisation and multiwavelength switchable Erbium Doped Fibre Lasers (EDFLs) using intracavity polarisation selective filters based on TFG devices with tilted structures at small, large and exact 45° angles forms another important contribution of this thesis.
Resumo:
This thesis address the creation of fibre Bragg grating based sensors and the fabrication systems which are used to manufacture them. The information is presented primarily with experimental evidence, backed up with the current theoretical concepts. The issues involved in fabricating high quality fibre Bragg gratings are systematically investigated. Sources of errors in the manufacturing processes are detected, analysed and reduced to allow higher quality gratings to be fabricated. The use of chirped Moiré gratings as distributed sensors is explored, the spatial resolution is increased beyond that of any previous work and the use of the gratings as distributed load sensors is also presented. Chirped fibre Bragg gratings are shown to be capable of operating as in-situ wear sensors, capable of accurately measuring the wear or erosion of the surface of a material. Two methods of measuring the wear are compared, giving a comparison between an expensive high resolution method and a cheap lower resolution method. The wear sensor is also shown to be capable of measuring the physical size and location of damage induced on the surface of a material. An array method is demonstrated to provide a high survivability such that the array may be damaged yet operate with minimal degradation in performance.
Resumo:
The rapid developments in computer technology have resulted in a widespread use of discrete event dynamic systems (DEDSs). This type of system is complex because it exhibits properties such as concurrency, conflict and non-determinism. It is therefore important to model and analyse such systems before implementation to ensure safe, deadlock free and optimal operation. This thesis investigates current modelling techniques and describes Petri net theory in more detail. It reviews top down, bottom up and hybrid Petri net synthesis techniques that are used to model large systems and introduces on object oriented methodology to enable modelling of larger and more complex systems. Designs obtained by this methodology are modular, easy to understand and allow re-use of designs. Control is the next logical step in the design process. This thesis reviews recent developments in control DEDSs and investigates the use of Petri nets in the design of supervisory controllers. The scheduling of exclusive use of resources is investigated and an efficient Petri net based scheduling algorithm is designed and a re-configurable controller is proposed. To enable the analysis and control of large and complex DEDSs, an object oriented C++ software tool kit was developed and used to implement a Petri net analysis tool, Petri net scheduling and control algorithms. Finally, the methodology was applied to two industrial DEDSs: a prototype can sorting machine developed by Eurotherm Controls Ltd., and a semiconductor testing plant belonging to SGS Thomson Microelectronics Ltd.
Resumo:
This research explores the links between the strategies adopted by companies and the mechanisms used to control the organisation. This is not seen as a one way process with the control system following from the strategy but rather as an interactive process between the control systems, the environment and the business strategy. The main proposition of the research, derived from a review of the relevant literature, is that the dimensions of Business Pro-Activity and Environmental Change provide a plausible explanation of the reasons why companies need to adopt different strategies in order to be successful in different markets. A model is proposed which links these dimensions with the business strategy, organisational structure, strategic planning system and management control systems. The model is used as a framework for analysing four companies in order to further our understanding of these interactions and the mechanisms which act to both promote and resist change. Whilst it is not suggested that the model in its present form is a perfect instrument it has, during the course of this research, proved to be an appropriate framework for analysing the various mechanisms used by four companies to formulate and implement their strategies. The research reveals that these should not be viewed independently but as a balanced system.
Resumo:
This thesis describes a study of the content and applicability of BS8800:1996 Guide to occupational health and safety management systems. The research is presented chronologically, with literature review and content analysis of SMS related guides and standards interwoven with two elements of qualitative empirical work. The first of these was carried out shortly after publication of BS8800 in 1996, a 'before-the-event' investigation of how organisations were intending to approach SMS implementation. The challenges faced by these organisations are reviewed against standard management theory, suggesting that the initial motivation for SMS implementation governs the approach organisations will adopt to guidance such as BS8800. The second phase of empirical work was undertaken in the context of OHSAS 18001, an auditable protocol based on BS8800, which allows organisations to certify their safety management systems. A discussion of the evolution of certifiable safety management system is presented, highlighting the similarities and differences between this, BS8800, SMS and wider management system standards. A case study then reviews the experiences of a catering company that implemented 18001, motivated by the opportunity for certification as a business benefit. The empirical work is used to comment on the guidance provided by BS8800, within its evolved role as guidance organisations may use for implementation of a SMS to be certified according to the specifications of OHSAS 18001. It is suggested that optimal implementation is facilitated by initial status review, continual improvement and the use of annexes, where there are used to make changes to the existing safety management system. This thesis concludes with a discussion of these elements, highlighting pertinent areas within BS8800 where revision or amendment may be appropriate.
Resumo:
This study is concerned with several proposals concerning multiprocessor systems and with the various possible methods of evaluating such proposals. After a discussion of the advantages and disadvantages of several performance evaluation tools, the author decides that simulation is the only tool powerful enough to develop a model which would be of practical use, in the design, comparison and extension of systems. The main aims of the simulation package developed as part of this study are cost effectiveness, ease of use and generality. The methodology on which the simulation package is based is described in detail. The fundamental principles are that model design should reflect actual systems design, that measuring procedures should be carried out alongside design that models should be well documented and easily adaptable and that models should be dynamic. The simulation package itself is modular, and in this way reflects current design trends. This approach also aids documentation and ensures that the model is easily adaptable. It contains a skeleton structure and a library of segments which can be added to or directly swapped with segments of the skeleton structure, to form a model which fits a user's requirements. The study also contains the results of some experimental work carried out using the model, the first part of which tests• the model's capabilities by simulating a large operating system, the ICL George 3 system; the second part deals with general questions and some of the many proposals concerning multiprocessor systems.
Resumo:
The work described was carried out as part of a collaborative Alvey software engineering project (project number SE057). The project collaborators were the Inter-Disciplinary Higher Degrees Scheme of the University of Aston in Birmingham, BIS Applied Systems Ltd. (BIS) and the British Steel Corporation. The aim of the project was to investigate the potential application of knowledge-based systems (KBSs) to the design of commercial data processing (DP) systems. The work was primarily concerned with BIS's Structured Systems Design (SSD) methodology for DP systems development and how users of this methodology could be supported using KBS tools. The problems encountered by users of SSD are discussed and potential forms of computer-based support for inexpert designers are identified. The architecture for a support environment for SSD is proposed based on the integration of KBS and non-KBS tools for individual design tasks within SSD - The Intellipse system. The Intellipse system has two modes of operation - Advisor and Designer. The design, implementation and user-evaluation of Advisor are discussed. The results of a Designer feasibility study, the aim of which was to analyse major design tasks in SSD to assess their suitability for KBS support, are reported. The potential role of KBS tools in the domain of database design is discussed. The project involved extensive knowledge engineering sessions with expert DP systems designers. Some practical lessons in relation to KBS development are derived from this experience. The nature of the expertise possessed by expert designers is discussed. The need for operational KBSs to be built to the same standards as other commercial and industrial software is identified. A comparison between current KBS and conventional DP systems development is made. On the basis of this analysis, a structured development method for KBSs in proposed - the POLITE model. Some initial results of applying this method to KBS development are discussed. Several areas for further research and development are identified.
Resumo:
Vesicular adjuvant systems composing dimethyldioctadecylammonium (DDA) can promote both cell-mediated and humoral immune responses to the tuberculosis vaccine fusion protein in mice. However, these DDA preparations were found to be physically unstable, forming aggregates under ambient storage conditions. Therefore there is a need to improve the stability of such systems without undermining their potent adjuvanticity. To this end, the effect of incorporating non-ionic surfactants, such as 1-monopalmitoyl glycerol (MP), in addition to cholesterol (Chol) and trehalose 6,6′-dibehenate (TDB), on the stability and efficacy of these vaccine delivery systems was investigated. Differential scanning calorimetry revealed a reduction in the phase transition temperature (T c) of DDA-based vesicles by ∼12°C when MP and cholesterol (1:1 molar ratio) were incorporated into the DDA system. Transmission electron microscopy (TEM) revealed the addition of MP to DDA vesicles resulted in the formation of multi-lamellar vesicles. Environmental scanning electron microscopy (ESEM) of MP-Chol-DDA-TDB (16:16:4:0.5 μmol) indicated that incorporation of antigen led to increased stability of the vesicles, perhaps as a result of the antigen embedding within the vesicle bilayers. At 4°C DDA liposomes showed significant vesicle aggregation after 28 days, although addition of MP-Chol or TDB was shown to inhibit this instability. Alternatively, at 25°C only the MP-based systems retained their original size. The presence of MP within the vesicle formulation was also shown to promote a sustained release of antigen in-vitro. The adjuvant activity of various systems was tested in mice against three subunit antigens, including mycobacterial fusion protein Ag85b-ESAT-6, and two malarial antigens (Merozoite surface protein 1, MSP1, and the glutamate rich protein, GLURP). The MP- and DDA-based systems induced antibody responses at comparable levels whereas the DDA-based systems induced more powerful cell-mediated immune responses. © 2006 The Authors.
Resumo:
Novel computing systems are increasingly being composed of large numbers of heterogeneous components, each with potentially different goals or local perspectives, and connected in networks which change over time. Management of such systems quickly becomes infeasible for humans. As such, future computing systems should be able to achieve advanced levels of autonomous behaviour. In this context, the system's ability to be self-aware and be able to self-express becomes important. This paper surveys definitions and current understanding of self-awareness and self-expression in biology and cognitive science. Subsequently, previous efforts to apply these concepts to computing systems are described. This has enabled the development of novel working definitions for self-awareness and self-expression within the context of computing systems.
Resumo:
We identify two different forms of diversity present in engineered collective systems, namely heterogeneity (genotypic/phenotypic diversity) and dynamics (temporal diversity). Three qualitatively different case studies are analysed, and it is shown that both forms of diversity can be beneficial in very different problem and application domains. Behavioural diversity is shown to be motivated by input diversity and this observation is used to present recommendations for designers of collective systems.
Resumo:
In the discussion - Ethics, Value Systems And The Professionalization Of Hoteliers by K. Michael Haywood, Associate Professor, School of Hotel and Food Administration, University of Guelph, Haywood initially presents: “Hoteliers and executives in other service industries should realize that the foundation of success in their businesses is based upon personal and corporate value systems and steady commitment to excellence. The author illustrates how ethical issues and manager morality are linked to, and shaped by the values of executives and the organization, and how improved professionalism can only be achieved through the adoption of a value system that rewards contributions rather than the mere attainment of results.” The bottom line of this discussion is, how does the hotel industry reconcile its behavior with that of public perception? “The time has come for hoteliers to examine their own standards of ethics, value systems, and professionalism,” Haywood says. And it is ethics that are at the center of this issue; Haywood holds that component in an estimable position. “Hoteliers must become value-driven,” advises Haywood. “They must be committed to excellence both in actualizing their best potentialities and in excelling in all they do. In other words, the professionalization of the hotelier can be achieved through a high degree of self-control, internalized values, codes of ethics, and related socialization processes,” he expands. “Serious ethical issues exist for hoteliers as well as for many business people and professionals in positions of responsibility,” Haywood alludes in defining some inter-industry problems. “The acceptance of kickbacks and gifts from suppliers, the hiding of income from taxation authorities, the lack of interest in installing and maintaining proper safety and security systems, and the raiding of competitors' staffs are common practices,” he offers, with the reasoning that if these problems can occur within ranks, then there is going to be a negative backlash in the public/client arena as well. Haywood divides the key principles of his thesis statement - ethics, value systems, and professionalism – into specific elements, and then continues to broaden the scope of each element. Promotion, product/service, and pricing are additional key components in Haywood’s discussion, and he addresses each with verve and vitality. Haywood references the four character types - craftsmen, jungle fighters, company men, and gamesmen – via a citation to Michael Maccoby, in the portion of the discussion dedicated to morality and success. Haywood closes with a series of questions derived from Lawrence Miller's American Spirit, Visions of a New Corporate Culture, each question designed to focus, shape, and organize management's attention to the values that Miller sets forth in his piece.
Resumo:
Background
Postpartum hemorrhage is the most significant contributor to maternal mortality globally, claiming 140,000 lives annually. Postpartum hemorrhage is a leading cause of maternal death in South Africa, with the literature indicating that 80 percent of the postpartum hemorrhage deaths in South Africa are avoidable. Ghana, as of 2010, witnesses 2700 maternal deaths annually, primarily because of poor quality of care in health facilities and services being difficult to access. As per WHO recommendations, uterotonics are integral to treating postpartum hemorrhage as soon as it is diagnosed. In case of persistent bleeding or limited availability of uterotonics, the uterine balloon tamponade (UBT) can be used as a second line of defense. If both these measures are unable to counter the bleeding, providers must perform surgical interventions. Literature on the UBT, as one tool in the protocol to address postpartum hemorrhage, has shown it to have success rates ranging from 60 to 100 percent. Despite the potential to lower the number of postpartum hemorrhage deaths in South Africa and Ghana, the UBT has not been incorporated widely in South Africa and Ghana. The aim of this study is to describe the barriers involved with integrating the UBT into South Africa and Ghana’s health systems to address postpartum hemorrhage.
Methods
The study took place in multiple sites in South Africa (Cape Town, Johannesburg, Durban and Mpumalanga) and in Accra, Ghana. South Africa and Ghana were selected because postpartum hemorrhage contributes greatly to their maternal mortality numbers and there is potential in both countries to lower those rates through greater use of the UBT. A total of 25 participants were interviewed through purposive sampling, snowball sampling and participant referrals, and included various categories of stakeholders integral to the integration process of a medical device. Individual in-depth interviews were used for data collection, with interview questions being tailored to each stakeholder category. The focus of the interviews was on the protocol used to counter postpartum hemorrhage, the frequency with which the UBT is used as part of the protocol, and the process of integrating it into the South Africa and Ghana’s health systems. The data collected were coded using NVivo and analyzed using content analysis.
Results
The barriers to integration of the uterine balloon tamponade to address postpartum hemorrhage in South Africa and Ghana were evident on the political, economic and health delivery levels. The results indicated that the barriers to integration in South Africa included the low recognition of postpartum hemorrhage as a problem, the lack of clarity surrounding the role of the Medicines Control Council as a regulatory body for medical devices, and low awareness of the UBT as an intervention to control postpartum hemorrhage. The barriers in Ghana were the cash constraints experienced by the Ghana Health Services to fund medical devices, a heavy reliance on donors for funding, and the lack of consistent knowledge on processes involving clinical trials for new medical devices in Ghana.
Conclusion
Existing literature on methods to counter postpartum hemorrhage to reduce maternal mortality has focused on and emphasized the efficacy of the UBT. Despite overwhelming evidence supporting the use of the UBT, many health systems across the world, particularly low-income countries, do not have access to the device owing to numerous barriers in integrating the device into obstetric care. This study illustrates the need to focus on incorporating the UBT into health systems for greater availability to health workers and its use as standard of care. Ultimately, this study can be used as a stepping-stone for more research on this subject, providing evidence to influence policymakers to integrate the UBT into their protocols for postpartum hemorrhage response.