In this thesis the stability and the region of attraction of nonlinear dynamical systems' equilibrium points are considered. Methods from linear programming are combined with theorems from the Lyapunov theory of dynamical systems to develop numerical algorithms. These algorithms deliver non-trivial information about the stability-behaviour of an equilibrium of a continuous, autonomous, nonlinear system. Two linear programs, LP1 and LP2, are developed. LP1 depends on a simply connected open neighborhood N of the equilibrium at the origin and two constants, a and m. The construction of LP1 implies that if it does not possess a feasible solution, then the corresponding system is not a,m-exponentially stable on N. LP2 has the property that every feasible solution of the linear program defines a piecewise-affine (piecewise-linear) Lyapunov function or a Lyapunov-like function V for the system.

Mein Grund, das Thema Menschen- und Buergerrechte zu waehlen, ist ein aktueller: das Besorgnis erregende Wiederaufleben nationalistischen Ungeistes im vereinigten Deutschland. Die sich haeufenden antisemitischen Anschlaege und rassistischen Gewalttaten, sowie die dabei des Oefteren zu beobachtende Gleichgueltigkeit der Umwelt, lassen daran zweifeln, dass die Menschenrechte in der Bundesrepublik bereits zum Gemeingut aller Buerger und Buergerinnen geworden sind. Das ist umso bestuerzender als das Bekenntnis zur Unantastbarkeit der Menschenwuerde und zu den unverletzlichen Menschenrechten in unserem Grundgesetz eine Reaktion auf das menschenverachtende Regime der Nationalsozialisten gewesen ist. Glaubten wir doch, dass die Erinnerung an, die Reue ueber und die Verantwortung fuer Auschwitz zu einem Grundelement der politischen Kultur in der Bundesrepublik Deutschland geworden sei.

Vorlesungen anlaesslich der Mercator-Professur 1999.

In this thesis a circuit technology is described, which enables an integrated controling of an active matrix of micromechanic spatial light modulators (SLM). Possible applications areas for micromechanic spatial light modulators are projection of still or moving images, maskless lithography and adaptive optics. Especially in the areas of lithography and adaptive optics typical requirements of light modulators are high optical resolutions, high accuracy of modulation and fast addressing in order to enable a fast image repetition rate. The developed circuits are optimised for use as a maskless litography system and provide a minimum pixel pitch of 16 <font face="Symbol">m</font><i>m</i>. Demonstrators with image areas of 256 x 256 pixels and a modulation resolution of 16 steps on each pixel enabled a minimum geometric lithographic resolution of less than 20 nm, using today available optics.

Within this thesis, instruments and methods were developed for sampling devices and chemical analysis of PM 10 and PM 2.5. These two particle size fractions are European standards for air quality monitoring since 1999. A specially designed "ambient air sampling system" for the direct collection of PM 10, PM 2.5 and PM 1 on TXRF-sample carriers for subsequent analysis by Total-Reflection X-Ray Fluorescence Analysis (TXRF) was constructed and calibrated in the laboratory. Additionally, a PM 1-Inlet for a High-Volume-Sampler was developed. As a result, the determination of mass concentrations as well as important chemical constituents (anions and cations, elemental and organic carbon, heavy metals, polycyclic aromatic hydrocarbons) is possible for the fine particle fraction PM 1. The newly developed instruments were used together with commercially available PM 10- and PM 2.5-samplers for a field campaign at a traffic-related measurement site. Data analyses showed good results concerning quality assurance and dem onstrated the complementarities of the different sampling systems. A detailed characterization of the ambient aerosols was obtained and a first source apportionment could be conducted. However, the results also showed that for an efficient air pollution reduction strategy, particle size fractionated emission measurements are necessary as well. Therefore, a PM 10/PM 2.5 in-stack cascade impactor was designed and calibrated. During measurements at various industrial plants, the newly developed instrument showed good results concerning reproducibility and plausible data in comparison with mass concentrations obtained with the plane filter device for the determination of total suspended particulates (TSP). A chemical characterization similar to the ambient air particles was conducted with TXRF for some of the samples. The results showed that size fractionated particle sampling together with multielemental analyses give characteristic patterns ("fingerprints") of emissions. In a next step, the information can be used for source apportionment by fingerprintmodelling and the quantification of the contribution of different sources to ambient air particle concentrations.

Let $I^2:=[-1,1] imes[-1,1]$ be the unit square and let $U$ be a subspace of $C(I^2)$. If $f$ is a continuous function, then $u^{ast}in U$ is said to be a {it best one--sided $L^1$--approximation to f in $U$ from above} if $u^{ast}geq f$ and $|f-u^{ast}|_1leq |f-u|$ for every $u in U$ with $ugeq f$. In this paper we consider the problem of characterization of such best approximants for the case where $U$ consists of all (quasi--)blending--functions of order $(m,1)$.

This thesis reports on the development of waveguide electroabsorption modulators based on multiple quantum well structures. The requirements to the modulator are given by the application in a fiberoptic E-field sensor system. The theoretical calculation of a quantum well structure which is tailored to the application, of the waveguide and of the electrical structure of the device is treated first. Following the technological realization of the developed concept and the characterization of the fabricated devices is described. The achieved performance of the modulators is discussed regarding the influence on the sensorsystem. This results in a minimum detectable field of 20 mV/m, a dynamic range of 105 dB and a frequency range from 100 MHz up to 8 GHz. In a final comparison between the performance of the sensorsystem which is dominated by the modulator and that of commercially available products based on lithiumniobate modulators the advantages of the developed concept are described. In addition to a high sensitivity and a broad frequency range also the operation of the modulator in optical reflection and the low polarization dependence of the modulator which is necessary for the use of conventional non polarization maintaining fibers are worth mentioning.

During the irradiation of 1-acetylnaphthaline in the presence of c,d-substituted olefines with a cyclic amine as a donor different products were generated. The reaction pathways were monitored by NMR-spectroscopy and it was proved that the main products were generated by a Photo-Diels-Alder-reaction. The c,d-olefines are added head-to-tail with the donor substituent in endo-position to the remaining aromatic system. Their structures could unambiguously be proven by single crystal x-ray structure analysis. Furthermore their thermal and photochemical properties were investigated: the activation enthalpies and activation entropies for their thermal decompositions were investigated and during their irradiation in solution with light of 254 nm a Di-<font face="Symbol">p</font>-methane-rearrangement could be observed.

In this thesis new methods for the automatic recognition of the content of image sequences are presented. Solutions to the following video sequences analysis tasks are developed: temporal decomposition of an image sequence into scenes and classification of the scenes, and the recognition of people and their movements in the image sequence. The temporal segmentation of a image sequence and the classification of the segments can be used for image sequences with a given content structure, like broadcast news. The image sequences have a defined chronology of scenes, which belong to certain content classes. The content classes and their chronology are represented by nested Hidden Markov models during the recognition. Another application of the Hidden Markov Modells are the classification of movements of objects in the image sequence. The recognition of human gestures for the application of human-computer-interaction is investigated. The recognition system is capable of recognizing a set of pre-defined gestures that are performed in the viewing area of a camera. The system is able to identify undefined movements and can distinguish them from the gestures. The final task is recognizing people visible in image sequences. The recognition of the people is done by recognizing their faces. The indexing of the faces is composed of the two sub-tasks: detection of the faces and recognition of the faces. It is shown that the face-based video indexing can be used to find known persons in the image sequence as well as to group the people in the sequence unsupervised.

This work describes the fabrication and usability of organic polymeric layers as gate insulators of field effect transistors (reference field effect transistors, REFET) that are dedicated to the determination of pH-reference potentials in electrolytic solutions. Based on the site binding model hydrophobe CF-polymers were investigated. Various techniques are able to generate polymeric layers that are characterized by low selective hydrogen ion sensitivity. Additional results indicate the necessity of reexamination the site binding model´s usability for polymers with low amount of dissociating sites. This work suggests a model assuming ion adsorption onto polymeric surfaces. This model describes results from CV-measurements as well as measurements on REFETs in a qualitative and quantitative way