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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Application of supervised and unsupervised learning to analysis of the arterial pressure pulse

Walsh, Andrew Michael, Graduate school of biomedical engineering, UNSW January 2006 (has links)
This thesis presents an investigation of statistical analytical methods applied to the analysis of the shape of the arterial pressure waveform. The arterial pulse is analysed by a selection of both supervised and unsupervised methods of learning. Supervised learning methods are generally better known as regression. Unsupervised learning methods seek patterns in data without the specification of a target variable. The theoretical relationship between arterial pressure and wave shape is first investigated by study of a transmission line model of the arterial tree. A meta-database of pulse waveforms obtained by the SphygmoCor"??" device is then analysed by the unsupervised learning technique of Self Organising Maps (SOM). The map patterns indicate that the observed arterial pressures affect the wave shape in a similar way as predicted by the theoretical model. A database of continuous arterial pressure obtained by catheter line during sleep is used to derive supervised models that enable estimation of arterial pressures, based on the measured wave shapes. Independent component analysis (ICA) is also used in a supervised learning methodology to show the theoretical plausibility of separating the pressure signals from unwanted noise components. The accuracy and repeatability of the SphygmoCor?? device is measured and discussed. Alternative regression models are introduced that improve on the existing models in the estimation of central cardiovascular parameters from peripheral arterial wave shapes. Results of this investigation show that from the information in the wave shape, it is possible, in theory, to estimate the continuous underlying pressures within the artery to a degree of accuracy acceptable to the Association for the Advancement of Medical Instrumentation. This could facilitate a new role for non-invasive sphygmographic devices, to be used not only for feature estimation but as alternatives to invasive arterial pressure sensors in the measurement of continuous blood pressure.
32

Zhodnocení manažerských funkcí a finanční analýza vybraného podniku / Estimation of managerial function and financial analysis of choises company

ŠPANVIRTOVÁ, Zuzana January 2011 (has links)
Purposes of thesis is estimation choice managerial function - scheduling, organization and controlling, and the financial analyses applied in the company and designed pertinent general changes for efficient run a business.
33

Improving Clustering of Gene Expression Patterns

Jonsson, Per January 2000 (has links)
The central question investigated in this project was whether clustering of gene expression patterns could be done more biologically accurate by providing the clustering technique with additional information about the genes as input besides the expression levels. With the term biologically accurate we mean that the genes should not only be clustered together according to their similarities in expression profiles, but also according to their functional similarity in terms of functional annotation and metabolic pathway. The data was collected at AstraZeneca R&D Mölndal Sweden and the applied computational technique was self-organising maps. In our experiments we used the combination of expression profiles together with enzyme classification annotation as input for the self-organising maps instead of just the expression profiles. The results were evaluated both statistically and biologically. The statistical evaluation showed that our method resulted in a small decrease in terms of compactness and isolation. The biological evaluation showed that our method resulted in clusters with greater functional homogeneity with respect to enzyme classification, functional hierarchy and metabolic pathway annotation.
34

The Origin of Wave Blocking for a Bistable Reaction-Diffusion Equation : A General Approach

Roy, Christian January 2012 (has links)
Mathematical models displaying travelling waves appear in a variety of domains. These waves are often faced with different kinds of perturbations. In some cases, these perturbations result in propagation failure, also known as wave-blocking. Wave-blocking has been studied in the case of several specific models, often with the help of numerical tools. In this thesis, we will display a technique that uses symmetry and a center manifold reduction to find a criterion which defines regions in parameter space where a wave will be blocked. We focus on waves with low velocity and small symmetry-breaking perturbations, which is where the blocking initiates; the organising center. The range of the tools used makes the technique easily generalizable to higher dimensions. In order to demonstrate this technique, we apply it to the bistable equation. This allows us to do calculations explicitly. As a result, we show that wave-blocking occurs inside a wedge originating from the organising center and derive an expression for this wedge to leading order. We verify our results with some numerical simulations.
35

Adaptation to unexpected changes : where ecosystems and multi-agent systems meet

Marin Pitalua, Cesar Augusto January 2011 (has links)
Unexpected changes occurring in complex and dynamic domains render supporting systems unsuited to the new conditions. Examples of such domains include business ecosystems, digital service ecosystems, manufacturing, transport, and city modelling. These are regarded as ecosystem domains. Multi-agent systems are seen as an appropriate technology for their support, yet they lack the required ability to adapt to unexpected changes. The research presented in this thesis aims to create a multi-agent system based in-silico model endowed with the capability of adaptation to unexpected changes occurring in ecosystem domains. The approach taken consists of applying adaptation properties of complex adaptive systems, such as natural ecosystems, to multi-agent systems to create one which can cope with unexpected changes. A dynamic agent-based ecosystem model called DAEM is formalised by combining characteristics of natural ecosystem and principles of adaptive multi-agent systems. A set of experiments is presented using a DAEM prototype to demonstrate its resilience to unexpected changes in a hypothetical ecosystem. A comparison is made against a simulated typical solution for showing how DAEM is more resilient to unexpected changes than the typical approach. This supports the claim of this thesis that DAEM represents a significant contribution to knowledge. A software embodiment of DAEM to drive adaptation in ecosystem domains is presented and placed in an execution context evaluated by two practical examples of ecosystem domains. These show how DAEM suggests interactions to the supporting system of the execution context, and incorporates taken decisions into the ecosystem regarding interactions with other individuals. This supports the claim that the DAEM software embodiment is suitable for providing adaptation support in ecosystem domains, thus representing another significant contribution of this thesis. The contributions to knowledge of this thesis are then a) a formal model of a dynamic agent-based ecosystem called DAEM; and b) a software embodiment of DAEM, called DAEM layer, to support adaptation in ecosystem domains. Future work includes further tests to analyse patterns and make estimations in existing ecosystems, among others.
36

Fog forecasting at Cape Town International Airport : a climatological approach

Van Schalkwyk, Lynette 15 February 2012 (has links)
Cape Town International Airport (CTIA) is located along the extreme southern portion of the west coast of South Africa which has the highest frequency of fog in the country. Fog occurs more frequently at CTIA than at any other of the international airports in South Africa. Fog forecasting research in South Africa has largely been neglected and fog forecast verification results show the urgent need for improvement. Accurate fog forecasts are imperative for the aviation industry to prevent costly flight delays and diversions. The main aim of this research is to improve the forecasts of fog at CTIA. The first step towards realising this aim is to provide aviation forecasters with a comprehensive fog climatology that encompasses all aspects of fog: from the seasonal characteristics, to detail regarding the types of fog that frequently occur, synoptic circulations associated with fog and characteristics of the vertical profile of the lower troposphere and boundary layer in which fog forms. Fog types at CTIA are classified by means of an objective hierarchical classification method that takes the formation mechanisms of fog into consideration. Self Organising Maps (SOMs) are used as a synoptic typing method, to determine the synoptic circulations that are most frequently associated with fog at CTIA. Case studies are presented to illustrate the formation mechanisms of 5 different fog types by means of the synoptic circulation, surface observations, satellite imagery and atmospheric soundings. Conclusions drawn from these case studies can assist forecasters with the identification of potential fog events in advance. It is recommended that climatology and case study results be made available to aviation forecasters at CTIA and that similar studies be conducted for all international airports in South Africa that are frequently affected by fog. Copyright / Dissertation (MSc)--University of Pretoria, 2011. / Geography, Geoinformatics and Meteorology / unrestricted
37

Statutory Union Recognition Provisions as Stimulants to Employer Anti-Unionism in Three Anglo-Saxon Countries

Gall, Gregor January 2009 (has links)
No / This article examines why employer opposition is stimulated by the introduction of statutory union recognition provisions in Britain, Ireland and the US. It examines the impact of the provisions for encouraging union organizing, which in turn stimulates employer anti-unionism, which then negates the intention of the provisions.
38

From the Soviet to the European Union : A Policy Study of SME Assistance Organising in Lithuania

Narbutaité Aflaki, Inga January 2009 (has links)
Establishment of a policy linkage between particular outspoken societal needs and their realisation via the body political is critical for recently democratised polities. In Lithuania, a former Soviet bloc country undergoing a complex transition, an urge from various societal groups for successful and adequate policies exemplify the importance of this linkage. The study inquires into its establishment during the transition from the Soviet to the EU by exploring collective action to assist Lithuanian SMEs -a new group of economic actors -with their transition period needs. Policy linkage is operationalised in terms of successful and adequate policies. Methodologically, the study examines the usefulness of bottom-up approach to policy organising for revealing policy process in the transition context. Theoretically, the study tests the explanatory power of the major bottom-up assumptions regarding the preconditions for policy linkage in the Lithuanian transition. Especially the role of the government and formal politicaladministrative institutions is explored. The study findings indicate very limited government, EU and mandated actors’ success in organising adequate SME assistance policies. Ad hoc collective actions with mixed types of actors and alternative structurations were found to frequently supplement for the policy linkage. Useful explanations to this were provided by the employed context, structural and behavioural factors. Active selforganising of policy receivers was a precondition significantly increasing the adequacy of the collective assistance action. Also adherence to the rule of law principles in policy process should not be undermined to increase chances of policy adequacy. Especially a combination of behavioural factors characteristic of social capital in the localities studied was found important to consider further. Policy learning is yet underestimated as a factor structuring policy action and enabling policy linkage. Lack of policy structures has implications for policy learning. The study also proposes policy adequacy as a complimentary indicator of transition success.
39

Security Assessment of IoT- Devices Grouped by Similar Attributes : Researching patterns in vulnerabilities of IoT- devices by grouping devices based on which protocols are running. / Säkerhetsbedömning av IoT-Enheter Grupperade efter Liknande Egenskaper

Sannervik, Filip, Magdum, Parth January 2021 (has links)
The Internet of Things (IoT) is a concept that is getting a lot of attention. IoT devices are growing in popularity and so is the need to protect these devices from attacks and vulnerabilities. Future developers and users of IoT devices need to know what type of devices need extra care and which are more likely to be vulnerable. Therefore this study has researched the correlations between combinations of protocols and software vulnerabilities. Fifteen protocols used by common services over the internet were selected to base the study around. Then an artificial neural network was used to group the devices into 4 groups based on which of these fifteen protocols were running. Publicly disclosed vulnerabilities were then enumerated for all devices in each group. It was found that the percentage of vulnerable devices in each group differed meaning there is some correlation between running combinations of protocols and how likely a device is vulnerable. The severity of the vulnerabilities in the vulnerable devices were also analyzed but no correlation was found between the groups. / Sakernas internet eller Internet of things (IoT) är ett koncept som fått mycket uppmärksamhet. IoT enheter växer drastisk i popularitet, därför är det mer nödvändigt att skydda dessa enheter från attacker och säkerhetsbrister. Framtida utvecklare och användare av IoT system behöver då veta vilka enheter som är mer troliga att ha säkerhetsbrister. Denna studie har utforskat om det finns något samband mellan kombinationer av aktiva protokoll i enheter och säkerhetsbrister. Femton vanligt använda protokoll valdes som bas för studien, ett artificiellt neuralt nätverk användes sedan för att gruppera enheter baserat på dessa protokoll. Kända sårbarheter i enheterna räknades upp för varje grupp. En korrelation mellan kombinationer av protokoll och trolighet för sårbarheter hittades. Allvarlighetsgraden av säkerhetsbristerna i sårbara enheter analyserades också, men ingen korrelation hittades mellan grupperna.
40

Ekonomisk styrning för förändring : en studie av ekonomiska styrinitiativ i hälso- och sjukvården / Management control for change : a study of management control initiatives in health care

Blomquist, Tomas, Packendorff, Johann January 1998 (has links)
Since the end of the 1980’s  Swedish county council managers has been preoccupied with planning and implementing organisational change in order to alleviate the financial problems and to create more efficient production systems. Many of these efforts to change have implied changing the systems for management accounting and control, changes that have been inspired both by market-oriented ideologies and by the governance principles of large corporations in the private sector. Literature on manage­ment accounting and control indicates however, that management is unintentionally contributing to the creation of organisational inertia and conservatism. This contradiction is formulated as a change dilemma; ”How can managerial principles that make organizations subject to  bureaucratization and inertia be used as important strategies for organizational change?” The purpose of the study is thus to analyze the use of management control systems as organizational change strategies in health care, employing a change perspective on management control. When used as a change strategy,  management accounting and control becomes manifest as management control initiatives. Actors handle these control inititatives by organising themselves around the issue at hand. This organising process ends or fades away when there are no need for further attention to the control initiative. Empirical studies were made in the councils of Västerbotten, Sörmland and Upp­sala counties. Management control initiatives investigated were performance-related pay, quality improvement work, systematic planning procedures, provider/purchaser-models, downsizing projects and profit center systems. The systems for management accounting and control appeared to structure health care organisations in terms of spatial structuring temporal structuring and actor categorization. The management control initiatives introduced were structured as extraordinary organising processes delimited in terms of space, time and involved actors. Actors in the administrative norm system participated with the intention to change the organisation, while those in the medical norm system aimed at just handling the initiative. Management control initiatives can therefore be seen as passing opportunities to change, passing in the sense that the organising processes are temporary by nature, opportunities in the sense that temporary re-coupling can be used to  achieve long-term change. One such opportunity is the formulation of control initiatives; the possibility of using simple and standardized change strategies can be useful, but only if they are also linked to the medical norm system. A second opportunity is the temporary organising processes; if the project form of organising change can also be conveyed to the medical norm system, management control initiatives could result in short, intense courses of events that actually change things. The third opportunity  s the recurrent  cyc ica  pro­ perties  of  management  accounting  and control  systems, enabling  recurrent  activities around the same themes, thereby keeping them alive. / <p>Diss. av båda förf. Umeå : Umeå univ., 1998 ; Framlägges för vinnande av filosofie doktorsexamen respektive ekonomie doktorsexamen.</p> / digitalisering@umu

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