Universiẗat, Diss.--Kassel, 2007.

Universiẗat, Diss.--Mannheim, 2007.

No description available.

The rapid growth and deployment of network technologies and Internet services has made security and management of networks a challenging research problem. This growth is accompanied by an exponential growth in the number of network attacks, which have become more complex, more organized, more dynamic, and more severe than ever. Current network protection techniques are static, slow in responding to attacks, and inefficient due to the large number of false alarms. Attack detection systems can be broadly classified as being signature-based, classification-based, or anomaly-based. In this dissertation, I present a multi-level anomaly based autonomic network defense system which can efficiently detect both known and unknown types of network attacks with a high detection rate and low false alarms. The system uses autonomic computing to automate the control and management of multi-level intrusion detection system and integrate the different components of the system. The system defends the network by detecting anomalies in network operations that may have been caused by network attacks. Like other anomaly detection systems, AND captures a profile of normal network behavior.In this dissertation, I introduce experimental results that evaluate the effectiveness and performance of the multi-level anomaly based autonomic network intrusion detection system in detecting network attacks. The system consist of monitoring modules, feature aggregation and correlation modules, behavior analysis modules, decision fusion module, global visualization module, risk and impact analysis module, action module, attack classification module, and the adaptive learning module. I have successfully implemented a prototype system based on my multi-level anomaly based approach. The experimental results and evaluation of our prototype show that our multi-level intrusion detection system can efficiently and effectively detect and protect against any type of network attacks known or unknown in real-time. Furthermore, the overhead of our approach is insignificant on the normal network operations and services.

Total evapotranspiration (ET) is the key process that links the land and the atmosphere via water, energy and carbon exchange. ET is a combination of evaporation and transpiration, which behave dynamically in very different ways. In this work we investigate the relative contribution of transpiration and soil evaporation to total ET in a semi-wooded, semi-arid forest in the Manitou Research Park northwest of Colorado Springs, CO. We use stable water isotopes measured at different levels within and outside the canopy, over a 30-day period (June 26 - July 26, 2010), using a field-deployable cavity ring-down spectrometer. The traditional "Keeling plot" analysis is used to partition the ET flux from moisture that comes from outside of the ecosystem, and then a simple model is used to partition the transpiration flux. In addition, we introduce a new alternative "multi-level" method to calculate the fraction of transpiration to total ET. Both the "Keeling plot" method and the "multi-level" method yield very similar fractions of transpiration to total ET, ranging from about 15% to about 85%. We compare both methodologies and discuss some of the corrections that must be made when measuring with high-frequency field-deployable instruments.

Since the 1980s, regions have taken a strong interest in EU policy-making and increasingly demanded representation in the process. This has given rise to the concept of multi-level governance (MLG) in EU policy-making, which stipulates that subnational and supranational actors will interact and thus to some extent erode the authority of central governments. However, due to the scarcity of case study research looking at concrete instances of policy-making, a number of questions remain about the extent and the effectiveness of the interaction between regional governments and European actors. In addition, the extent and origins of differences in regional activity across regions and member states remain unclear. This thesis aims to contribute to the MLG debate by developing a theoretical framework with a set of hypotheses about regional activism in EU policy-making on the basis of rational choice institutionalist assumptions. It then investigates how seven legislative regions from four member states (the UK, Germany, Belgium and Austria) represent their interests in two concrete instances of EU policy-making and tests the core hypotheses against these fourteen cases. The thesis contributes to the MLG debate in three ways. Firstly, the principal objective of the thesis is to analyse the impact of different types of domestic intergovernmental relations on the strategies of regions at the European level. It is argued that the level and nature of a region's activity on the European level depends on the opportunities for influence in the domestic European policy-making process and the constraints that domestic rules place on European level activity. Secondly, a number of factors that could account for different levels of regional activity both within and between states are analysed. Domestic conflict and the capacity of a region are found to be particularly relevant for regional mobilisation. Finally, the thesis discusses the relative importance of domestic channels compared to European channels of regional interest representation, thus addressing one of the fundamental questions in the MLG literature. It is argued that unmediated interaction between European actors and regional governments is less common than predicted by the MLG literature, but that it can be effective, especially in cases where regions devise a comprehensive strategy of interest representation.

Health and well-being of older adults has become a worldwide public health concern and has been attracting increasing attention from scholars across the globe. But little is known about the health of the Chinese elderly. Using data from the China Health and Retirement Longitudinal Study (CHARLS) --Pilot, a pilot survey in 2008 in two provinces of China, Gansu and Zhejiang, this dissertation examines the association between social capital at both the individual- and community- levels and three health outcomes among older adults in China. A series of multi-level models were estimated using SAS 9.2. Statistical results indicate that such individual-level social capital variables as perceived help and support in the future, help from others, and birthplace significantly impacted health among older Chinese adults. When examining the relationship between community-level social capital and health, this study confirms the significant association between community-level social capital and good health independent of individual-level predictors. This study also indicates that the impact of gender and rural-urban Hukou status interacts with the province of residence. The results were discussed in terms of cultural legacy in the Chinese cultural setting, the current social dynamics related to old age support, health-related government reforms, and various disparities across different regions and across different social groups in China.

Doctor of Philosophy / Department of Electrical and Computer Engineering / Ruth Douglas Miller / This dissertation presents the design of a novel multi-level inverter with FACTS capability for small to mid-size (10–20kW) permanent-magnet wind installations using modular multi-level converter (MMC) topology. The aim of the work is to design a new type of inverter with D-STATCOM option to provide utilities with more control on active and reactive power transfer of distribution lines. The inverter is placed between the renewable energy source, specifically a wind turbine, and the distribution grid in order to fix the power factor of the grid at a target value, regardless of wind speed, by regulating active and reactive power required by the grid. The inverter is capable of controlling active and reactive power by controlling the phase angle and modulation index, respectively. The unique contribution of the proposed work is to combine the two concepts of inverter and D-STATCOM using a novel voltage source converter (VSC) multi-level topology in a single unit without additional cost. Simulations of the proposed inverter, with 5 and 11 levels, have been conducted in MATLAB/Simulink for two systems including 20 kW/kVAR and 250 W/VAR. To validate the simulation results, a scaled version (250 kW/kVAR) of the proposed inverter with 5 and 11 levels has been built and tested in the laboratory. Experimental results show that the reduced-scale 5- and 11-level inverter is able to fix PF of the grid as well as being compatible with IEEE standards. Furthermore, total cost of the prototype models, which is one of the major objectives of this research, is comparable with market prices.

Compared to microarray-based genotyping, next-generation whole genome-sequencing (WGS) studies have the strength to provide greater information for the identification of rare variants, which likely account for a significant portion of missing heritability of common human diseases. In WGS, family-based studies are important because they are likely enriched for rare disease variants that segregate with the disease in relatives. We propose a multilevel model to detect disease variants using family-based WGS data with longitudinal measures. This model incorporates the correlation structure from family pedigrees and that from repeated measures. The iterative generalized least squares (IGLS) algorithm was applied to estimation of parameters and test of associations. The model was applied to the data of Genetic Analysis Workshop 18 and compared with existing linear mixed effect (LME) models. The multilevel model shows higher power at practical p-value levels and a better type I error control than LME model. Both multilevel and LME models, which utilize the longitudinal repeated information, have higher power than the method that only utilize data collected at one time point.

Le but de la thèse est de réaliser des filtres accordable en technologie planaire multi-niveaux proposé par l'entreprise allemande IHP. Les filtres sont réalisés aux ondes millimétriques,principalement autour de 60 GHz et 140 GHz. Nous étudions l'accordabilité en fréquence mais aussi l'accordabilité en bande passante ne utilisant un concept nouveau établie au cours de cette thèse. Les premiers résultats concernant les filtres accordables en fréquence ont permit la rédaction de plusieurs articles. Maintenant, nous venons de recevoir les mesures prouvant notre nouveau concept permettant l'accord en fréquence et en bande passante des filtres planaires à base de résonateurs en anneau / The thesis aim is to realize tunable filters using the BiCMOS planar technologie provided by thegerman company IHP. We are working on millimeterwaves, mainly 60 GHz and 140 GHz. Westudy the frequency tunability but also the bandwidth tunability using a new concept provided bythe study carried during this thesis. The first study about frequency tunability aimed to severalconference articles. Now, we just have the measurements proving the new concept of frequencycontrol while maintening a bandwidth control of planar ring filters