Magnetresonanztomographische Studie zur altersabhängigen Abbildung der Wachstumsknorpel des distalen Radius des Pferdes unter besonderer Berücksichtigung des Epiphysenfugenknorpels. Es wurden magnetresonanztomographische Untersuchungen von 28 Gliedmaßenabschnitten des distalen Radius im Alter von zwei Tagen bis 17 Jahren durchgeführt. Die Studie wurde an einem 1,5 Tesla Magnetom “Symphony“ (Siemens) in vier unterschiedlichen Sequenzen (T1-gewichtet T1w, T2-gewichtet T2w, Protonendichte PD, T2 Double Echo in Steady State T2-dess) und zwei Schnittebenen (dorsal, sagittal) durchgeführt. Die Darstellung der knorpeligen Wachstumsregionen des distalen Radius mit besonderem Hinblick auf seine Epiphysenfuge wurde deskriptiv erfasst und altersbedingte Unterschiede definiert. Die durchschnittliche Dicke des sich darstellenden Epiphysenfugenknorpels wurde in zwei Sequenzen (T1w und T2-dess) vermessen und in Bezug zu dem ansteigenden Alter des Probenmaterials gesetzt. Die Proben konnte man fünf Gruppen zuordnen. In Gruppe 1 konnten sowohl der Wachstumsknorpel der distalen Ossifikationszentren als auch die knorpeligen Anteile der Epi- und Apophysenfugen dargestellt werden. In der Gruppen 2 ließen sich die Apo- und Epiphysenfugen darstellen, in Gruppe 3 nur die Epiphysenfugen. Gruppe 4 beschrieb partiell geschlossene Epiphysenfugen und in Gruppe 5 stellten sich nur 88 noch Fugennarben dar. Eine alterskorrelierende Abnahme der mittleren Knorpeldicke der Epiphyse konnte mittels Vermessungen der Knorpelschichten nachgewiesen werden. Der hyaline Knorpel war mit den gewählten Sequenzen sehr gut beurteilbar. Der Wachstumsknorpel der Epi- und Apophysen stellte sich in den T1w und PD mit hell-intermediärer und in den T2w mit intermediärer Signalintensität dar. Die knorpeligen Anteile der Epi- und Apophysenfuge wurden in T1w intermediär bis hellintermediär, in T2w hell-intermediär und in der PD hell-intermediär bis hyperintens dargestellt. Angrenzende Strukturen wie die subchondrale Knochenplatte und die Mineralisationszone der Epiphysenfuge konnten in dunkel-intermediären bis hypointensen Signalen abgebildet werden. Die Magnetresonanztomographie (MRT) hat sich als geeignetes Verfahren erwiesen, die knorpeligen Strukturen der Wachstumsregion des distalen Radius des Pferdes bildlich wiederzugeben. Altersabhängige strukturelle Unterschiede konnten im MRT dargestellt werden. Damit leistet die vorgestellte Studie einen wichtigen Beitrag über die anatomischen Verhältnisse und deren physiologische Darstellung.

The diploma thesis is concerned with solving security problems in local computer networks. The main part deals with the solution of authorization of wireless clients against the RADIUS server and with the proposal of domain controller using open-source products and the tools of operating system GNU/Linux.

Tire tread health is essential for safe operation of a passenger vehicle. Worn out tires significantly increases the risk of traffic accidents and hydroplaning. This thesis investigates the possibility to detect tire tread wear by estimating the effective rolling radius of a tire. The effective rolling radius of a tire is affected by several different factors. As to not confuse change in external factors with actual tire tread wear, there is therefore a need to compensate the effective rolling radius to nominal conditions, to make sure that the change in compensated rolling radius is only due to the tire tread wear. This raises the questions: how can the effective rolling radius be estimated? Can it be compensated with respect to external factors? The behavior of the tire changes between different tire models. This is because different models uses different materials, patterns, internal structure etc. This raises an additional question. Can a compensation model with the same parameter values be used in all vehicles of the same type no matter the tires of the vehicle, or is there a need for an adaptive compensation model that adapts the parameters to the current tire? This thesis investigates how the estimation of the tires effective rolling radius can be improved by estimating the velocity using sensor fusion between GPS- and IMU-signals. This was done using an Extended Kalman Filter. Furthermore, this thesis proposes different ways of compensating a tires effective rolling radius with respect to external factors and compares these methods with each other to obtain the most efficient compensation method. After finding an appropriate compensation method, further investigations regarding the need of adaptivity between tires was performed to find out if the compensation factors can be used on the same vehicle model with different tire sets. Ultimately, the investigations showed that the estimation of the effective rolling radius of a tire using sensor fusion was not fruitful due to limitations set by the IMU. If the vehicle had been equipped with a 6-axis IMU instead of a 3-axis IMU, this method might be feasible. The method that directly calculates the effective rolling radius from GPS-velocity and wheel speed gave a more accurate rolling radius signal. The compensation of the effective rolling radius can be achieved with respect to velocity, tire pressure and tire temperature. The most advantageous compensation method proposed in this thesis was a polynomial compensation model. Lastly, when investigating the need of adaptive compensation factors it was found that these compensation factors needs to be adaptive between tire sets.

This thesis is devoted to the analysis of problems that arise when long products of matrices taken in a given set are constructed. A typical application is the stability of switched linear systems. The stability of a discrete-time linear system is a classical engineering problem that has been well understood for long: the dynamics can be expressed in terms of the eigenvalues of the matrix ruling the system. A more complicated problem arises when the dynamical system can switch, that is, if the matrix changes over time. If this matrix is taken from a given set but can be chosen arbitrarily in this set at every time, the stability problem turns to the computation of a quantity, the joint spectral radius of the set of matrices, introduced in the early sixties. While this quantity appears to be hard to compute, it has acquired more and more importance during the last decades, and new applications of the joint spectral radius in engineering or mathematics are frequently discovered. It has for instance been proved useful for the analysis of regularity of fractals, for the continuity of wavelets, or for autonomous agents detection in sensor networks. In the first part of this thesis, we present a theoretical survey of the joint spectral radius, including old and new results. The joint spectral subradius, which is its stabilizability counterpart, is also considered. In a second part, we study some applications related to long products of matrices. We first analyse in detail a problem in coding theory, that has been recently shown to involve a joint spectral radius computation. We then propose a new application of the joint spectral radius (and related quantities) to a classical problem in number theory, namely the counting of overlap-free words. We then turn to problems related with autonomous agents detection: we analyse the trackability of sensor networks, and introduce and analyse a new notion, namely the observability of sensor networks.

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Die Osteoporose ist als häufigste Knochenerkrankung im Alter die Ursache vieler Beeinträchtigungen. Definiert wird sie über die Knochendichte, die unter anderem mit der peripheren quantitativen Computertomographie (pQCT) bestimmt werden kann. Mit unseren Daten aus Knochendichtemessungen per pQCT am distalen Radius (XCT 2000) und an der distalen Tibia (XCT 3000) konnten wir im Tukey-HSD-Test zeigen, dass die Knochendichteparameter an oberer und unterer Extremität gut miteinander korrelieren. Es wurden die trabekuläre und die totale Dichte sowie der polare stress-and-strain-Index berücksichtigt. Die trabekuläre Knochendichte an der Tibia, dem gewichtstragenden Knochen, ist höher als die am Radius. Einflussnahme auf die Knochendichte konnte mittels Regressionsanalyse für das Alter, das Geschlecht, die Größe, das Gewicht und den BMI nachgewiesen werden. Die altersbedingte Abnahme der Knochendichte ist an der Tibia stärker ausgeprägt als am Radius. Bei der Frau bedingt eine hohe totale Dichte am Radius eine höhere Festigkeit an der Tibia als bei entsprechenden Dichtewerten beim Mann. Unter Mitberücksichtigung des Alters steigt die Festigkeit an der Tibia beim Mann mit den Jahren an. Bei der Frau sinkt sie, wie auch am Radius, mit steigendem Alter. Das Gewicht nimmt signifikanten Einfluss auf die untere Extremität, nicht jedoch auf den Radius. Die Betrachtung des BMI zeigt, dass nicht die reine Gewichtszunahme sondern die Kombination aus Größe und Gewicht diesen positiven Effekt erzielen, Fettleibigkeit ab dem Adipositasgrad aber einen negativen Einfluss auf die Knochendichte und -festigkeit hat. / As a common bone disease in elderly patients osteoporosis is a cause of severe physical impairment. It is defined by bone mineral density (BMD), which can be determined by peripheral quantitative computer tomography (pQCT). Our data from BMD measurements made by pQCT at the distal radius (XCT 2000) and at the distal tibia (XCT 3000) shows through application of the Tukey-HSD-tests that BMD values at the upper and lower extremities correlate with each other. Total and trabecular BMD as well as the polar stress-and-strain index are considered. Trabecular BMD at the body weight bearing distal tibia is higher than at the distal radius. Influence on BMD was verified by regression analysis for age, sex, height, weight and BMI. Age-related decrease of BMD is more distinct at the tibia than at the radius. In women high total BMD accounts for higher strength at the tibia than it does for corresponding values in men. Considering age, strength of the tibia increases in men during the years. In women it decreases, like it does at the radius. Weight has significant influence on the lower extremity, however not on the radius. Regarding the BMI, not just an increase in mass but a combination of weight and height causes this positive effect. Obesity above level I has a negative influence on BMD and bone strength.

A simulation scheme is proposed to analyze the effects of elliptic-conical lensed fiber parameters on the coupling efficiency between a 980nm laser diode and single-mode fiber(SMF). The variation of fiber tip shapes with different melting zone volumes was investigated in this thesis. The heat-transfer finite element model in MARC package is employed to simulate the temperature distribution during the melting process. The free convection is considered in predicting the melting zone. Due to the surface tension, a round tip may be solidificated. In this study an elliptical tip lens is expected to improve the coupling efficiency. The microlens shapes with different radius of curvature is simulated with the software of Surface Evolver. The coupling efficiency of 980nm laser source and different elliptic-conical lensed fiber is calculated by utilizing the ZEMAX optical analysis software. The Taguchi method is employed to evaluate the effect of tip shape parameters on the coupling efficiency. The optimal elliptic-conical lensed fiber parameters has also been proposed. The efficiency loss introduced from the misalignments in laser module packaging has also been discussed in this study.

The main objective for this degree project was to analyze the Endpoint Security Solutions developed by Cisco, Microsoft and a third minor company solution represented by InfoExpress. The different solutions proposed are Cisco Network Admission Control, Microsoft Network Access Protection and InfoExpress CyberGatekeeper. An explanation of each solution functioning is proposed as well as an analysis of the differences between those solutions. This thesis work also proposes a tutorial for the installation of Cisco Network Admission Control for an easier implementation. The research was done by reading articles on the internet and by experimenting the Cisco Network Admission Control solution. My background knowledge about Cisco routing and ACL was also used. Based on the actual analysis done in this thesis, a conclusion was drawn that all existing solutions are not yet ready for large-scale use in corporate networks. Moreover all solutions are proprietary and incompatible. The future possible standard for Endpoint solution might be driven by Cisco and Microsoft and a rude competition begins between those two giants.

In this thesis, we have analyzed the coupling gap dependent micro-ring loss in a single ring all-pass filter configuration using the two dimension (2D) finite difference time domain (FDTD) and EIM (effective index method). We utilized a new analysis scheme by calculating the transmission signal as a function of input wavelength and fitting the transmission spectrum with a phenomenological ring loss parameter. This novel scheme circumvents the complex waveguide mode analysis process, when the coupling gap is narrow and the all-pass coupling region becomes multi-mode. We first find that the radiation loss increases rapidly with decreasing coupling gap width. Our results show that the intrinsic bending losses of silicon micro-rings (on oxide) with the radius of 1.5 £gm, 2.5£gm, and 5£gm are about 20 dB/cm, 3 dB/cm, 1 dB/cm for TE polarization modes, respectively. For TM modes, the intrinsic bending losses with the radius of 1.5£gm, 2.5 £gm, and 5£gm are about 2573 dB/cm, 64 dB/cm, and 0.8 dB/cm, respectively. Next, we find that power coupling coefficients of the single ring all-pass filter configuration using the ring to ring couplers are much higher than the bus to ring couplers. The radiation losses of the ring to ring couplers for TM modes are improved significantly in all coupling gap widths. In a high-density integrated optics circuit, specially designed ring coupling region device structure is needed to address this serious optical loss issue.

In this study, twenty-seven experiments of transport and hydrographic observations were conducted at 9 bridges along the Love River during the period between 2001/12/20 and 2003/9/10. In each experiment repeated measurements were made at each bridge every two hours for a total period of 12 hours. An additional experiment (the 28th experiment) was conducted at 2004/6/16 in the Chihsien Bridge which consists of continuous measurements of velocity, depth and turbidity with a total length of 27 hours. Our results indicate that the Love River is influenced by the incoming tides from the river mouth up to the Dingxin Bridge. The tidal range is approximately 1m during spring tides (10cm during neap tides) at river mouth. The velocity at the Chihsien Bridge has a high frequency variation with a period of approximately 1 hour and amplitude of 20 cm/s during the 28th experiment. Salinity variations are in phase with tides, while turbidity and tides are out of phase. Harmonic analysis of depth, velocity, salinity and turbidity data all indicate that K1 is the principal tidal constituent followed by M2. River transport in the lower estuary is mainly comprised of two parts: tide and river discharge. The tidal induced transport is estimated to be ¡Ó30 CMS and net river discharge is about 1~9 CMS. The upper estuary is affected by two transport mechanisms: agricultural runoff and rain precipitation. After analyzing the measurement results, the transport of the upper branches is estimated to be 0~0.5 CMS during dry seasons and 1~5 CMS during rainy seasons. The agricultural transport reaches its maximum value in January with an estimated rate of 1~2.8 CMS. For the upper branches of Love River, the ratio£\between the hydraulic depth D and hydraulic radius R is found to reach a constant value of 0.9~1.0 when the transport Q is less than 2CMS, and£\is 0.8~0.9 when Q is greater than 2 CMS. The relationship between Q and the section factor TaDb, where T is the channel width, is found to be TD5/3=7.171Q (Dingxin Bridge) and TD5/3=0.744Q (Hougang Bridge) based on Manning formula. Finally, the relationship between Q and D is found to be D=1.811Q0.2981 (Longxin bridge) and D=0.266Q0.256 (Hougang Bridge).