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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.
21

Financial protection through community-based health insurance in Rwanda

Muhongerwa, Diane 01 July 2014 (has links)
Community-Based Health Insurance (CBHI) in Rwanda was promulgated as the best alternative to address the financial barriers for accessibility to health care services for the poor population and the informal sector. The purpose of this study was to investigate whether CBHI reduce Out-of-pocket health expenses for their members as compared to non-members and to what extent CBHI provide financial protection for the poorest population. This research based itself on secondary source of data primarily collected for a prospective quasi-experimental design which evaluated the impact of Performance-Based Financing. The primary study had reported on the Out-Of-Pocket expenses for health by members and non-members of CBHI; residing in a sample of 1961 households; in addition to their demographics and socio-economic characteristics. The findings indicate that insured individuals were about 2.6 times more likely to utilize health care services than respondents without health insurance. It is also worth noting that households with health insurance coverage were less likely to experience a catastrophic health expenditure than households without health insurance (aOR: 0.744; 95% CI:[0.586 - 0.945]), and that the effect of health insurance coverage was higher in people living in poor households than in people living in middle or richer households / Health Studies / M.A. (Public Health)
22

Defect mechanisms in diode lasers at high optical output power

Hempel, Martin 24 October 2013 (has links)
In dieser Arbeit wird der Catastrophic Optical Damage (COD) zeitaufgelöst untersucht um die beteiligten physikalischen Mechanismen zu identifizieren. Der COD Prozess konnte zeitlich in drei Phasen unterteilt werden, die Alterung, der thermische Runaway (selbst verstärkende Rückkopplung) und das Sekundärschadenswachstum. Die erste Phase konnte durch eine neu eingeführte Art der beschleunigten Bauteilalterung auf den Nanosekunden-Bereich reduziert werden. Die Rolle des Laser-Lichtfelds als Energiequelle des COD-Prozesses wurde experimentell bestätigt. Die genutzten thermographischen Techniken erlaubten eine in-situ Verfolgung des Defektwachstums. Diese direkte Messung der Ausbreitung, die Modellierung des Wärmeflusses und eine kristallographische Materialanalyse zeigen, dass das Material, welches von der Defekt-Front passiert wurde, innerhalb von Nanosekunden zu substanziell tieferen Temperaturen zurückkehrt. Verschiedene experimentelle Ansätze bestätigen das Vorhandensein einer Temperatur im Bereich von 1200°C-1500°C an der Schadensfront während des gesamten Degradationsprozesses. Dabei hat sich gezeigt, dass selbst wenn keine Laseremission mehr vorliegt, die verstärkte spontane Emission ausreicht, um den fortschreitenden Degradationsprozessmit Energie zu versorgen. Für den Start des thermischen Runaway muss ein bestimmter Temperaturunterschied zwischen der späteren COD-Position und dem übrigen aktiven Lasermaterial erreicht werden. Die vorliegende Arbeit zeigt verschiedene Mechanismen auf, die zu einer solchen Situation führen können. Dabei spielen auch physikalische Eigenschaften der verwendeten Materialsysteme und Schichtstrukturen eine entscheidende Rolle. Ein neu im Rahmen dieser Arbeit entwickeltes Modell zur Beschreibung der räumlichen Schadensausbreitung nutzt diesen Umstand, um die Defektkinetik ex-post zu rekonstruieren. Dies ermöglicht das Aufzeigen von Schwachstellen im Bauelement. / The scope of this thesis is the time-resolved investigation of the catastrophic optical damage (COD) and the identification of the underlying physical mechanisms. The COD has been separated in three temporal phases: the aging, the thermal runaway (self-amplifying feedback mechanism), and the secondary defect growth. It was possible to reduce the first phase to a couple of nano-seconds by applying a new accelerated life test scheme. It was experimentally verified that the laser light is the primary energy source of COD. The applied thermographic technologies allowed an in-situ tracing of the defect growth. A fast thermo cycle during the passage of the defect front was confirmed by this direct measurement, a modeling of the heat flow, and a crystallographic material analysis. Different experimental setups indicate the presence of a temperature in the range of 1200°C-1500°C at the defect front, during the entire COD-degradation. Even if no lasing action is present anymore, the amplified spontaneous emission is sufficient to provide enough energy for further defect growth. In order to initiate the thermal runaway, a specific temperature difference is necessary between the COD-starting location and the remaining active laser material. This thesis provides an analysis of the mechanisms leading to such a situation. This kind of analysis was used to develop a new model of the geometrical defect growth. The ability to re-construct the defect dynamics based on ex-post analysis of the defect pattern allows for the identification of bottlenecks in the investigated device design leading to COD.
23

Financial protection through community-based health insurance in Rwanda

Muhongerwa, Diane 01 July 2014 (has links)
Community-Based Health Insurance (CBHI) in Rwanda was promulgated as the best alternative to address the financial barriers for accessibility to health care services for the poor population and the informal sector. The purpose of this study was to investigate whether CBHI reduce Out-of-pocket health expenses for their members as compared to non-members and to what extent CBHI provide financial protection for the poorest population. This research based itself on secondary source of data primarily collected for a prospective quasi-experimental design which evaluated the impact of Performance-Based Financing. The primary study had reported on the Out-Of-Pocket expenses for health by members and non-members of CBHI; residing in a sample of 1961 households; in addition to their demographics and socio-economic characteristics. The findings indicate that insured individuals were about 2.6 times more likely to utilize health care services than respondents without health insurance. It is also worth noting that households with health insurance coverage were less likely to experience a catastrophic health expenditure than households without health insurance (aOR: 0.744; 95% CI:[0.586 - 0.945]), and that the effect of health insurance coverage was higher in people living in poor households than in people living in middle or richer households / Health Studies / M.A. (Public Health)
24

Avoiding Catastrophic Forgetting in Continual Learning through Elastic Weight Consolidation

Evilevitch, Anton, Ingram, Robert January 2021 (has links)
Image classification is an area of computer science with many areas of application. One key issue with using Artificial Neural Networks (ANN) for image classification is the phenomenon of Catastrophic Forgetting when training tasks sequentially (i.e Continual Learning). This is when the network quickly looses its performance on a given task after it has been trained on a new task. Elastic Weight Consolidation (EWC) has previously been proposed as a remedy to lessen the effects of this phenomena through the use of a loss function which utilizes a Fisher Information Matrix. We want to explore and establish if this still holds true for modern network architectures, and to what extent this can be applied using today’s state- of- the- art networks. We focus on applying this approach on tasks within the same dataset. Our results indicate that the approach is feasible, and does in fact lessen the effect of Catastrophic Forgetting. These results are achieved, however, at the cost of much longer execution times and time spent tuning the hyper- parameters. / Bildklassifiering är ett område inom dataologi med många tillämpningsområden. En nyckelfråga när det gäller användingen av Artificial Neural Networks (ANN) för bildklassifiering är fenomenet Catastrophic Forgetting. Detta inträffar när ett nätverk tränas sekventiellt (m.a.o. Continual Learning). Detta innebär att nätverket snabbt tappar prestanda för en viss uppgift efter att den har tränats på en ny uppgift. Elastic Weight Consolidation (EWC) har tidigare föreslagits som ett lindring genom applicering av en förlustfunktion som använder Fisher Information Matrix. Vi vill utforska och fastställa om detta fortfarande gäller för moderna nätverksarkitekturer, och i vilken utsträckning det kan tillämpas. Vi utför metoden på uppgifter inom en och samma dataset. Våra resultat visar att metoden är genomförbar och har en minskande effekt på Catastrophic Forgetting. Dessa resultat uppnås dock på bekostnad av längre körningstider och ökad tidsåtgång för val av hyperparametrar.
25

La gouvernance d'un système : vers une gestion dynamique des risques / The governance of a system : towards a dynamic management of risks

Bakkour, Darine 02 December 2013 (has links)
L'augmentation du nombre des sinistres à grande échelle d'origine climatique, technologique, sanitaire, et bien d'autres, nous interpelle sur le mode de gouvernance des systèmes concernés, sur les choix de couverture de ces risques et sur les mesures de prévention mises en place. La question qui a animé notre recherche est : dans quelle mesure la gouvernance d'un système favorise-t-elle la gestion des risques ? Notre analyse empirique s'appuie sur deux cas d'étude, qui se concentrent, sur la gouvernance d'un système face à des risques catastrophiques pour l'un, et des risques communs pour l'autre. D'une part, les risques majeurs sont connus comme étant très peu probables mais avec de possibles lourdes conséquences. La dynamique de la gouvernance adaptative, pour la gestion des risques majeurs d'un système, souligne la nécessité d'adopter une approche flexible (dynamique). Nous proposons ainsi un cadre d'évaluation de la capacité d'adaptation d'un système dans le domaine des risques majeurs. D'autre part, les risques communs affectent l'ensemble de la population. Face aux risques communs dont les conséquences s'étalent dans le futur, nous considérons que la gouvernance adaptative dans une démocratie délibérative se réfère au paradigme selon lequel la gouvernance permet aux décideurs de se projeter vers le long terme. Le dilemme consiste à prendre (à présent) des décisions (c.-à-d. des risques, au sens général du terme) dont les effets (ou les conséquences) ne se font sentir que dans le futur. La gouvernance d'un système doit favoriser la gestion des risques. Notre travail de recherche est structuré autour de trois parties (i.e. « Gouvernances et risques », « La gouvernance d'un système exposé à un risque catastrophique », et « La gouvernance d'un système exposé à un risque commun »), chacune composée de trois chapitres. L'objectif ultime de la gestion des risques, voire des incertitudes qui caractérisent nos sociétés contemporaines est une raison d'être légitime des modes dynamiques de gouvernance qui incitent les différents acteurs à travailler ensemble, de diverses manières, afin de relever les défis auxquels ils sont confrontés. / The increase in large-scale climate, technological, sanitary, and many other types of losses, challenges us on the governance of the concerned systems, the choices made to hedge these risks and implement prevention measures. The question which animated our research is : to what extent the governance of a system promotes a better risk management?Our empirical analysis is based on two case studies which focus on the governance of a system while facing catastrophic risks for first one, and on common risks for the other. On the one hand, catastrophic risks are known to be highly improbable but with possible serious consequences. The dynamic of the adaptive governance system facing catastrophic risks underlines the need for a (dynamic) flexible approach. We therefore suggest an assessment framework for the adaptive capacity of a system in the field of catastrophic risks. On the other hand, common risks affect the whole population. We consider that the adaptive governance in a deliberative democracy refers to the governance paradigm which addresses common risks whose consequences spread out into the future. Thus, it induces decision makers to look at the long run. The dilemma consists in taking (now) decisions (i.e. Risk, in the general sense of the word) whose effects (or consequences) are only felt in the future. The governance of a system shall promote risk management. Our research is structured into three parts (i.e. "Governance and risk", "Governance of a system exposed to a catastrophic risk" and "Governance of a system exposed to a common risk"), each composed of three chapters. The ultimate objective of the management of risks, or even uncertainties, which characterize our contemporary societies is a legitimate reason for having dynamic modes of governance that prompt different actors to work together in various ways, in order to meet challenges they face.
26

Extension on Adaptive MAC Protocol for Space Communications

Li, Max Hongming 06 December 2018 (has links)
This work devises a novel approach for mitigating the effects of Catastrophic Forgetting in Deep Reinforcement Learning-based cognitive radio engine implementations employed in space communication applications. Previous implementations of cognitive radio space communication systems utilized a moving window- based online learning method, which discards part of its understanding of the environment each time the window is moved. This act of discarding is called Catastrophic Forgetting. This work investigated ways to control the forgetting process in a more systematic manner, both through a recursive training technique that implements forgetting in a more controlled manner and an ensemble learning technique where each member of the ensemble represents the engine's understanding over a certain period of time. Both of these techniques were integrated into a cognitive radio engine proof-of-concept, and were delivered to the SDR platform on the International Space Station. The results were then compared to the results from the original proof-of-concept. Through comparison, the ensemble learning technique showed promise when comparing performance between training techniques during different communication channel contexts.
27

A essay on the housing price jump risk and the catastrophe risk for the property insurance company

Chang, Chia-Chien 29 September 2008 (has links)
This dissertation includes two topics. For the first topic about the housing price jump risk, we use EM gradient algorithms to estimate parameters of the jump diffusion model and test whether the US monthly housing price have jump risk during 1986 to 2006. Then, in order to obtain a viable pricing framework of mortgage insurance contracts, this paper uses the jump diffusion processes of Merton (1976) to model the dynamic process of housing price. Using this model, we investigate the impact of price jump risk on the valuation of mortgage insurance premium from jump intensity, abnormal volatility of jump size and normal volatility. Empirical results indicate that the abnormal volatility of jump size has the most significant impact on the mortgage insurance premium. For the second topic about the catastrophe risk, we investigate that, for catastrophic events, the assumption that catastrophe claims occur in terms of the Poisson process seems inadequate as it has constant intensity. We propose Markov Modulated Poisson process to model the arrival process for catastrophic events. Under this process, the underlying state is governed by a homogenous Markov chain, and it is the generalization of Cummins and Geman (1993, 1995), Chang, Chang, and Yu (1996), Geman and Yor (1997) and Vaugirard (2003a, 2003b). We apply Markov jump diffusion model to derive pricing formulas for catastrophe insurance products, included catastrophe futures call option, catastrophe PCS call spread and catastrophe bond. We use the data of PCS index and the annual number of hurricane events during 1950 to 2004 to test the quality of the fitting under the Markov Modulated Poisson process and the Poisson process. We reach the conclusion that the Markov Modulated Poisson process is fitter than the Poisson process and Weiner process in modeling the arrival rate of hurricane events when pricing three insurance products. Hence, if different status of climate environment has significant different arrival intensity in real economy, using jump diffusion model to evaluate CAT insurance products could cause significant mispricing.
28

ECONOMIC ANALYSIS OF CARBON SEQUESTRATION UNDER CATASTROPHIC RISK AND PRICE UNCERTAINTY IN KENTUCKY

Hu, Lijiao 01 January 2014 (has links)
Internalizing carbon value for forest landowners has the potential to increase carbon supply in forest and mitigate CO2 in the atmosphere. In this study, we developed a modified Hartman model to investigate how payments of carbon offsets impact the optimal management of hardwood forests in Kentucky under condition of catastrophic events. Different carbon markets were modeled and several sensitivity analyses were performed to examine varied management strategies to achieve maximized financial return or highest environmental benefits. Furthermore, another model was developed to incorporate the impact of risk aversion to price uncertainty using E-V model. We were able to identify the most favorable scenarios for landowners and society in the face of price variability and catastrophic risk.
29

Behandling med eculizumab vid katastrofalt antifosfolipidsyndrom

Cronin, Jennifer January 2018 (has links)
Bakgrund: Eculizumab (Solirisâ) är en monoklonal antikropp som är riktad mot C5 i komplementsystemet. Bindning av eculizumab till C5 förhindrar proteinets klyvning och därmed också aktivering. Eculizumab är godkänt för behandling av atypiskt hemolytiskt uremiskt syndrom och paroxysmal nokturn hemoglobinuri. Sedan behandlingen blivit godkänd för dessa tillstånd har även ”off-label use” vid andra tillstånd varit betydande. En tidigare studie har visat att uppemot 50 % av behandling med eculizumab är off-label use, det vill säga behandling utanför de idag godkända indikationerna. Ett av dessa tillstånd är katastrofalt antifosfolipidsyndrom (KAPS), ett mycket allvarligt tillstånd som karaktäriseras av multipla tromboser som utvecklas under kort tid i flera organ vid vilket eculizumab visat sig ha en potentiellt positiv effekt. KAPS kan uppstå om man har bakomliggande antifosfolipid syndrom (APS) och kan utlösas vid en så kallad ”second hit”, en inflammatorisk stressreaktion orsakad av exempelvis en infektion eller kirurgiskt ingrepp. Eculizumab är ett särläkemedel och är en av de dyraste läkemedelsbehandlingarna i världen. Syfte: Syftet med denna studie var att analysera fall där KAPS behandlats med eculizumab för att utvärdera om eculizumab bör vara standarbehandling vid detta tillstånd. Likheter och olikheter mellan fallen studerades för att utvärdera när det kan vara lämpligt att behandla med eculizumab. Syftet var också att utvärdera detta utifrån ett ekonomiskt perspektiv. Metod: Detta är en litteraturstudie där sökningar i PubMed gjorts efter rapporter som beskriver fall där patienter med KAPS eller som ansetts haft en risk att utveckla KAPS behandlats med eculizumab. Åtta rapporter med totalt tio fall inkluderades och analyserades. Resultat: De rapporter som analyserades visade övergripande en tydlig effekt av behandling med eculizumab. Eculizumab tolkades också i vissa fall som ett kostnadseffektivt alternativ genom bland annat förkortad intensivvård och dialysbehov. Slutsats: Eculizumab har i de fall som analyserats visat sig ha en avgörande betydelse för att reversera ett livshotande tillstånd och skulle kunna vara standardbehandling vid KAPS och förebyggande av KAPS. För att eculizumab, eller en annan komplementhämmare, ska kunna bli standardbehandling krävs ytterligare forskning på KAPS och dess relation till komplementsystemet. / Catastrophic antiphospholipidsyndrome (CAPS) is a rare but highly fatal condition characterized by thrombosis in multiple organs, often associated with a rapid progression of disease and serious complications for the patient. A rapid diagnosis and treatment is therefore a key to manage this condition. The conventional treatment, which consists of anticoagulation, steroids, plasma exchange and intravenous immunoglobulins, reduces mortality but CAPS is still associated with high mortality. To find the mechanism of how and why this condition evolves is therefore important. There has been progress to find out the pathogenesis and one clue appears to be the complement system. Therefore, a new type of treatment has been used in patients who have been diagnosed with antiphosphlipidsyndrome (APS) and have had a risk of developing CAPS, or have been diagnosed with definitive or probable CAPS. This treatment is aimed at inhibiting parts of the complement system and consists of a monoclonal antibody called eculizumab. Lately eculizumab has been used off label in patients diagnosed with CAPS and in patients that has been at risk of developing CAPS. The results of this treatment have been positive and have therefore been considered as a possible alternative for treating CAPS. The aim of this study was to evaluate if eculizumab can be an alternative to treat patients with CAPS and patients diagnosed with APS who have a risk of developing CAPS. In order to evaluate treatment with eculizumab in patients with CAPS, searches on cases were done in the database PubMed for reports of patients with CAPS or at risk of developing CAPS who have been treated with eculizumab. Eight reports with a total of ten cases were found and used in order to answer the hypothesis of this study. In the ten cases that were analyzed there was a clear connection between the treatment and the recovery. In both patients with CAPS and patients at risk of developing CAPS the treatment with eculizumab was considered of significant importance. Because of the rarity of this condition, every case makes significant impact into the understanding of this potentially fatal condition. For future new cases, the present report will stand as an important source for making decisions about treatment with eculizumab. With time and more cases with positive results eculizumab has the potential to become conventional treatment for CAPS.
30

Analýza technických rezerv v neživotním pojištění / Analysis of technical provisions in non-life insurance

Masner, Václav January 2008 (has links)
Technical provisions represent the liabilities of the insurance company to its clients. In contrast to other liabilities the exact volume of technical provisions is not predetermined. This thesis is focused on technical provisions in non-life insurance, mainly on claims provisions, that are the most significant type of provisions in non-life classes of business. The aim is to analyse methods leading to the estimate of the value of ultimate claims arising from insurance events, that happened during the given time period. Claims provision is the part of ultimate claims, that has not already been paid. The speciality of some insurance classes as well as several factors, that may influence the correct estimate of claims provisions, are also analysed. The goal of this thesis is to present various possible ways, how to deal with these factors in order to prevent distortions of the estimate of ultimate claims. Finally the evaluation of the exactness of estimates and consequences, that the incorrect estimate may cause, are presented.

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