28 resultados para computing and software systems
em Aston University Research Archive
Resumo:
OBJECTIVES: The objective of this research was to design a clinical decision support system (CDSS) that supports heterogeneous clinical decision problems and runs on multiple computing platforms. Meeting this objective required a novel design to create an extendable and easy to maintain clinical CDSS for point of care support. The proposed solution was evaluated in a proof of concept implementation. METHODS: Based on our earlier research with the design of a mobile CDSS for emergency triage we used ontology-driven design to represent essential components of a CDSS. Models of clinical decision problems were derived from the ontology and they were processed into executable applications during runtime. This allowed scaling applications' functionality to the capabilities of computing platforms. A prototype of the system was implemented using the extended client-server architecture and Web services to distribute the functions of the system and to make it operational in limited connectivity conditions. RESULTS: The proposed design provided a common framework that facilitated development of diversified clinical applications running seamlessly on a variety of computing platforms. It was prototyped for two clinical decision problems and settings (triage of acute pain in the emergency department and postoperative management of radical prostatectomy on the hospital ward) and implemented on two computing platforms-desktop and handheld computers. CONCLUSIONS: The requirement of the CDSS heterogeneity was satisfied with ontology-driven design. Processing of application models described with the help of ontological models allowed having a complex system running on multiple computing platforms with different capabilities. Finally, separation of models and runtime components contributed to improved extensibility and maintainability of the system.
Resumo:
Contemporary software systems are becoming increasingly large, heterogeneous, and decentralised. They operate in dynamic environments and their architectures exhibit complex trade-offs across dimensions of goals, time, and interaction, which emerges internally from the systems and externally from their environment. This gives rise to the vision of self-aware architecture, where design decisions and execution strategies for these concerns are dynamically analysed and seamlessly managed at run-time. Drawing on the concept of self-awareness from psychology, this paper extends the foundation of software architecture styles for self-adaptive systems to arrive at a new principled approach for architecting self-aware systems. We demonstrate the added value and applicability of the approach in the context of service provisioning to cloud-reliant service-based applications.
Resumo:
When a visual stimulus is continuously moved behind a small stationary window, the window appears displaced in the direction of motion of the stimulus. In this study we showed that the magnitude of this illusion is dependent on (i) whether a perceptual or visuomotor task is used for judging the location of the window, (ii) the directional signature of the stimulus, and (iii) whether or not there is a significant delay between the end of the visual presentation and the initiation of the localization measure. Our stimulus was a drifting sinusoidal grating windowed in space by a stationary, two-dimensional, Gaussian envelope (σ=1 cycle of sinusoid). Localization measures were made following either a short (200 ms) or long (4.2 s) post-stimulus delay. The visuomotor localization error was up to three times greater than the perceptual error for a short delay. However, the visuomotor and perceptual localization measures were similar for a long delay. Our results provide evidence in support of the hypothesis that separate cortical pathways exist for visual perception and visually guided action and that delayed actions rely on stored perceptual information.
Resumo:
A hybrid approach for integrating group Delphi, fuzzy logic and expert systems for developing marketing strategies is proposed in this paper. Within this approach, the group Delphi method is employed to help groups of managers undertake SWOT analysis. Fuzzy logic is applied to fuzzify the results of SWOT analysis. Expert systems are utilised to formulate marketing strategies based upon the fuzzified strategic inputs. In addition, guidelines are also provided to help users link the hybrid approach with managerial judgement and intuition. The effectiveness of the hybrid approach has been validated with MBA and MA marketing students. It is concluded that the hybrid approach is more effective in terms of decision confidence, group consensus, helping to understand strategic factors, helping strategic thinking, and coupling analysis with judgement, etc.
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 reports on the results of case studies in four commercial banks in Nigeria. The study focuses how management accounting and control systems (MCS) operate in the four banks. The study is motivated by the dearth of literature on management accounting practices in the developing world in general and in Nigeria in specific. The case study approach adopted in conducting the research was useful in exploring the dynamics of the MCS in the organisations. Data was gathered from two sources. First, semi-structured interviews were conducted with managers at the head office, regional office and branches of each bank. The participants were selected from different backgrounds and managerial levels to provide broader understanding of the operations of the MCS. Second, various internal and external documents were reviewed to provide supporting evidence for the interview results. New institutional sociology (NIS) provided the theoretical framework to understand the results. NIS provided explanations for how the MCS in the four banks were shaped by diverse external and internal factors. The key factors identified as shaping the operations of the MCS were the need to comply with the regulatory environment (coercive isomorphism), the need to maintain social and cultural support (normative isomorphism) and the need to imitate successful organisations in order to appear legitimate (mimetic isomorphism). The study also examines the interplay between the institutional forces, market forces and infra-organisational power relations. This analysis is necessary to overcome the criticism of NIS that it downplays the role of market forces, agency and intra-organisational relations. The findings of the study have implications for understanding the operations of MCS in the developing world.
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:
The modulation of 5-hydroxytryptamine (5-HT)-related head-twitchbehaviour by antimigraine drugs and migraine triggers was examined inmice. The antimigraine drugs examined produced either inhibition or noeffect on 5-HT-related head-twitching. On the basis of these resultsit is suggested that 5-HT-related head-twitching is unlikely to beuseful in the preclinical screening and discovery of systemically-activeantimigraine agents. The migraine triggers examined, tyramineand beta-PEA initially produced a repeatable complex time-relatedeffect on 5-HT-related head-twitching, with both inhibition andpotentiation of this behaviour being observed, however, when furtherexamination of the effect of the migraine triggers on 5-HT-relatedhead-twitching was attempted some time later the effects seeninitially were no longer produced. The effect of (±)-1-<2, 5-dimethoxy-4-iodophenyl)-2-aminopropane,((±)DOl), on on-going behaviour of mice and rats was examined. Shakingbehaviour was observed in both species. In mice, excessive scratchingbehaviour was also present. (±)DOl-induced scratching and shakingbehaviour were found to be differentially modulated by noradrenergicand serotonergic agents, however, the fact that both behaviours wereblocked by ritanserin (5-HT2/5-HT1c receptor antagonist) and inhibitedby FLA-63 (a dopamine-beta-oxidase inhibitor which depletesnoradrenaline), suggests the pathways mediating these behaviours mustbe convergent in some manner, and that both behaviours require intact5-HT receptors, probably 5-HT2 receptors, for their production. Ingeneral, the behavioural profile of (±)DOI was as expected for anagent which exhibits high affinity binding to 5-HT2/5-HT1c receptors.Little sign of the 5-HTl-related '5-HT syndrome' was seen in eithermice or rats. The effect of a variety of noradrenergic agents on head-twitchinginduced by a variety of shake-inducing agents was examined. A patternof modulatory effect was seen whereby the modulatory effect of thenoradrenergic agents on 5-hydroxytryptophan <5-HTP) (and in some cases, 5-methoxy-N,N-dimethyltryptamine (5-MeODMT)) was found to be the opposite of that observed with quipazine and (±)DOI. The relationship between these effects, and their implications for understanding the pharmacology of centrally acting drugs is discussed.
Resumo:
Manufacturing planning and control systems are fundamental to the successful operations of a manufacturing organisation. 10 order to improve their business performance, significant investment is made by companies into planning and control systems; however, not all companies realise the benefits sought Many companies continue to suffer from high levels of inventory, shortages, obsolete parts, poor resource utilisation and poor delivery performance. This thesis argues that the fit between the planning and control system and the manufacturing organisation is a crucial element of success. The design of appropriate control systems is, therefore, important. The different approaches to the design of manufacturing planning and control systems are investigated. It is concluded that there is no provision within these design methodologies to properly assess the impact of a proposed design on the manufacturing facility. Consequently, an understanding of how a new (or modified) planning and control system will perform in the context of the complete manufacturing system is unlikely to be gained until after the system has been implemented and is running. There are many modelling techniques available, however discrete-event simulation is unique in its ability to model the complex dynamics inherent in manufacturing systems, of which the planning and control system is an integral component. The existing application of simulation to manufacturing control system issues is limited: although operational issues are addressed, application to the more fundamental design of control systems is rarely, if at all, considered. The lack of a suitable simulation-based modelling tool does not help matters. The requirements of a simulation tool capable of modelling a host of different planning and control systems is presented. It is argued that only through the application of object-oriented principles can these extensive requirements be achieved. This thesis reports on the development of an extensible class library called WBS/Control, which is based on object-oriented principles and discrete-event simulation. The functionality, both current and future, offered by WBS/Control means that different planning and control systems can be modelled: not only the more standard implementations but also hybrid systems and new designs. The flexibility implicit in the development of WBS/Control supports its application to design and operational issues. WBS/Control wholly integrates with an existing manufacturing simulator to provide a more complete modelling environment.
Resumo:
Internally heated fluids are found across the nuclear fuel cycle. In certain situations the motion of the fluid is driven by the decay heat (i.e. corium melt pools in severe accidents, the shutdown of liquid metal reactors, molten salt and the passive control of light water reactors) as well as normal operation (i.e. intermediate waste storage and generation IV reactor designs). This can in the long-term affect reactor vessel integrity or lead to localized hot spots and accumulation of solid wastes that may prompt local increases in activity. Two approaches to the modeling of internally heated convection are presented here. These are based on numerical analysis using codes developed in-house and simulations using widely available computational fluid dynamics solvers. Open and closed fluid layers at around the transition between conduction and convection of various aspect ratios are considered. We determine optimum domain aspect ratio (1:7:7 up to 1:24:24 for open systems and 5:5:1, 1:10:10 and 1:20:20 for closed systems), mesh resolutions and turbulence models required to accurately and efficiently capture the convection structures that evolve when perturbing the conductive state of the fluid layer. Note that the open and closed fluid layers we study here are bounded by a conducting surface over an insulating surface. Conclusions will be drawn on the influence of the periodic boundary conditions on the flow patterns observed. We have also examined the stability of the nonlinear solutions that we found with the aim of identifying the bifurcation sequence of these solutions en route to turbulence.
Resumo:
DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY AND INFORMATION SERVICES WITH PRIOR ARRANGEMENT
Resumo:
With recent expansions in technology, mobile computing continues to play a vital role in all aspects of our lives. Digital technology tools such as Web browsing, media tracking, social media, and emailing have made mobile technology more than just a means of communication but has widespread use in business and social networks. Developments in Technologies for Human-Centric Mobile Computing and Applications is a comprehensive collection of knowledge and practice in the development of technologies in human –centric mobile technology. This book focuses on the developmental aspects of mobile technology; bringing together researchers, educators, and practitioners to encourage readers to think outside of the box.
Resumo:
DUE TO COPYRIGHT RESTRICTIONS ONLY AVAILABLE FOR CONSULTATION AT ASTON UNIVERSITY LIBRARY SERVICES WITH PRIOR ARRANGEMENT