Chemnitz, Techn. Univ., Studienarb., 1996. / Nebent.: Sun's neuer Kern für objektorientierte, verteilte Anwendungen ; teilw.: Spring. Archiviert als Projektarbeit.

Communication in microkernel-based systems is much more frequent than system calls known from monolithic kernels. This can be attributed to the placement of system services into their own protection domains. Communication has to be fast to avoid unnecessary overhead. Also, communication channels in microkernel-based systems are used for more than just remote procedure calls. In distributed systems, which also have a componentized design, it is state of the art to use tools to generate stubs for the communication between components. The communication interfaces of components are described in an interface definition language (IDL). In contrast to distributed systems, components of a microkernel-based system run on the same architecture and message delivery is guaranteed. In this Thesis, I explore the different kinds of communication, which can be used in microkernel-based systems, as well as their possible representation in IDL. Specifically, I introduce the syntax to describe kernel objects in IDL. I discuss the complexity of IDL compilers and its relation to the complexity of the IDL. Furthermore, I evaluate the performance of the communication stubs generated by different IDL compilers and discuss techniques to minimize performance overhead in generated stubs. I validated these techniques by implementing the Drops IDL Compiler - Dice. Finally, this Thesis presents a mechanism to measure the frequency and performance of invocations of generated communication code. I used this technique to conduct measurements in highly complex systems and introducing the least possible overhead.

Communication in microkernel-based systems is much more frequent than system calls known from monolithic kernels. This can be attributed to the placement of system services into their own protection domains. Communication has to be fast to avoid unnecessary overhead. Also, communication channels in microkernel-based systems are used for more than just remote procedure calls. In distributed systems, which also have a componentized design, it is state of the art to use tools to generate stubs for the communication between components. The communication interfaces of components are described in an interface definition language (IDL). In contrast to distributed systems, components of a microkernel-based system run on the same architecture and message delivery is guaranteed. In this Thesis, I explore the different kinds of communication, which can be used in microkernel-based systems, as well as their possible representation in IDL. Specifically, I introduce the syntax to describe kernel objects in IDL. I discuss the complexity of IDL compilers and its relation to the complexity of the IDL. Furthermore, I evaluate the performance of the communication stubs generated by different IDL compilers and discuss techniques to minimize performance overhead in generated stubs. I validated these techniques by implementing the Drops IDL Compiler - Dice. Finally, this Thesis presents a mechanism to measure the frequency and performance of invocations of generated communication code. I used this technique to conduct measurements in highly complex systems and introducing the least possible overhead.

In dieser Arbeit werden die neuen objektorientierten Mechanismen von Sun's neuem Kern ¨Spring¨ vorgestellt. Hier wurden erstmals die Standards der OMG (Object Managment Group) umgesetzt. An einem kleinen Beispiel wird das Programmieren unter Spring erlaeutert.

Les techniques de la télédétection thermique (TIR) ont été appliquées dans les études environnementales spécialement pour l’extraction de la température de surface. La télédétection infrarouge thermique (TIR) est la seule approche possible pour l’extraction de la température de surface (Coll & et al., 2005). De nombreux auteurs ont étudié la température de surface et ont proposé des algorithmes spécifiques pour son extraction à partir de l’image satellitale. (Abdellaoui A. , 1985a) propose un modèle de la relation température de surface-température de l’air près du sol en vue de l’extension spatiale des modèles d’analyse des paramètres de surface ; (Abdellaoui & et al., 1986) proposent un modèle global d’analyse du bilan d’énergie à l’interface sol-atmosphère qui permet d’extraire l’évolution journalière de la température de surface et de l’évapotranspiration ainsi qu’une valeur moyenne de l’inertie thermique; (Becker & Li, 1990) ont appliqué la méthode split-window sur la surface terrestre en prenant en considération l’émissivité de surface. (Sobrino & et al., 1996) ont développé un algorithme split-window pour l’estimation de la température de surface en donnant des coefficients de split-window adapté au capteur ATSR. (Gillespie & et al., 1998) ont appliqué la méthode TES qui utilise une approche de séparation de la température et de l’émissivité pour retrouver la température de surface. (Qin & et al., 2001a) ont trouvé utile de s’intéresser à une seule bande thermique en développant un algorithme mono-window pour l’extraction de la température de surface à partir des données Landsat TM6.Certains logiciels de traitement d’images classiques tels que ENVI, IDRISSI, ERDAS intègrent un module de génération d’une image température de surface en utilisant des paramètres de calibration et d’ajustement. Par ailleurs dans ces logiciels la température de surface ne représente qu’un petit élément dans un ensemble orienté surtout vers le visible. Notre objectif principal dans ce travail est d’élaborer un outil d’extraction et de traitement de la température de surface et son exploitation dans le suivi de l’évolution du paysage en nous basant sur des processus faisant intervenir la chaleur tels les îlots de chaleur ou l’assèchement par évaporation. Les algorithmes que nous développons dans ce travail utilisent un certain nombre de méthodes de calcul de la température de surface à partir des données satellitales ; ces algorithmes sont intégrés dans un module spécifique et accessible à partir d’une interface qui permet à l’utilisateur de choisir la méthode d’extraction la mieux adaptée à son étude / The techniques of thermal remote sensing (TIR) were applied in environmental studies especially for the extraction of the surface temperature. Thermal infrared (TIR) remote sensing is the only possible approach to retrieve LST (Coll & et al., 2005). Many authors have studied this parameter and proposed specific algorithms for its extraction from satellite imaging. (Abdellaoui A. , 1985a) proposed a model for the relationship of the air temperature near the ground for the spatial extension of surface-based parameters models; (Abdellaoui & et al., 1986) proposed a global analysis model of energy balance at the soil-atmosphere interface that extracts the daily changes in surface temperature and evapo-transpiration and an average value of thermal inertia; (Becker & Li, 1990) applied the split-window method on the earth's surface by taking into consideration the surface emissivity; (Sobrino & et al., 1996) have developed a split-window algorithm for estimating the surface temperature by providing split-window coefficients adapted to ATSR sensor. (Gillespie & et al., 1998) applied the TES method that uses a separation approach of the temperature and emissivity to find the surface temperature. (Qin & et al., 2001a) have found it useful to focus on a single thermal band by developing a single-window algorithm for extracting the surface temperature from Landsat TM6 Data.Some conventional image processing software such as ENVI, IDRISSI, ERDAS incorporate a module for generating a surface temperature image using the calibration and adjustment parameters. However, the surface temperature in these software represents only one small element of a set of outputs that are primarily dedicated to the visible rather than to the infrared spectrum. Our main objective in this work is to develop an extraction and processing tool for the surface temperature and its use for the monitoring of the landscape evolution. Using IDL as its image processing engine, our tool is equipped with graphical user interface and user-driven modules. The algorithms developed employ a number of methods to calculate the surface temperature based on satellite data; the interface allows the selection of the most suitable extraction method for the user’s study

<p>Software Defined Radio (SDR) is a conception of implementing radio functions in computer software, instead of having electronics performing the functions. This thesis aims to compare two different ways of implementing these functions, or waveforms.</p><p>The Software Communications Architecture (SCA) is an open standard developed by the United States Department of Defense. It uses a CORBA interface environment to make waveform applications interoperable and platform independent. This method of developing SDR is compared to an open-source initiative going by the name GNU Radio.</p><p>Two waveform applications are developed, one transmitter using SCA, and one receiver using GNU Radio. The analog radio interface is simulated using the sound cards of two regular PCs. The development is done using the C++ and Python programming languages.</p><p>This thesis examines pros and cons of the two SDR methods, as well as performing studies of Software Defined Radio in general.</p>

Airborne lidar bathymetry (ALB) is a method used to survey and map coastal and littoral zones. Along with extracting seafloor depth and reflectance in the surveyed area, a fundamental requirement of these surveys is to detect underwater targets, hazards, or obstructions. The ability to detect underwater targets depends on a target's dimensions and reflectance, the depth and turbidity of the water, system and survey configuration, data processing capabilities, and algorithmic sophistication. Understanding the effects of each of these factors on the performance of underwater target detection is essential in determining the target detection capabilities of a proposed ALB system. After detailing the development of a simulation environment to model received ALB system waveforms, this work explores the theoretical target detection capabilities of an ALB system.

Software Defined Radio (SDR) is a conception of implementing radio functions in computer software, instead of having electronics performing the functions. This thesis aims to compare two different ways of implementing these functions, or waveforms. The Software Communications Architecture (SCA) is an open standard developed by the United States Department of Defense. It uses a CORBA interface environment to make waveform applications interoperable and platform independent. This method of developing SDR is compared to an open-source initiative going by the name GNU Radio. Two waveform applications are developed, one transmitter using SCA, and one receiver using GNU Radio. The analog radio interface is simulated using the sound cards of two regular PCs. The development is done using the C++ and Python programming languages. This thesis examines pros and cons of the two SDR methods, as well as performing studies of Software Defined Radio in general.

Made available in DSpace on 2014-06-12T15:59:28Z (GMT). No. of bitstreams: 2 arquivo5129_1.pdf: 1241668 bytes, checksum: f51ca348f57f1072bfe811018105944c (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2002 / Este trabalho apresenta uma arquitetura Hardware/Software para aplicações em processamento de imagens. O sistema tem como intuito a implementação de um sistema de visão computacional direcionado ao controle de tráfego urbano, o qual visa detectar a presença de veículos em uma área de interesse, dentro do campo visual capturado por uma câmera de vídeo digital instalada em uma via pública. A metodologia de trabalho contempla o desenvolvimento inicial do algoritmo de processamento de imagens digitais através de ferramentas de alto nível de abstração (IDL - Interactive Data Language), explorando as alternativas de implementação com experimentos e técnicas de realce e análise das imagens. Na sequência do fluxo do projeto adotado, a etapa seguinte constitui-se na tradução das funções que compõem o algoritmo desenvolvido em linguagens de médio nível (C/C++), desenvolvendo um código executável que implementa o algoritmo e agregando controle ao usuário do sistema acerca dos ajustes funcionais e resultados obtidos no processamento. Dentro da metodologia de projeto hardware/ software, trechos do algoritmo que representam grande demanda do tempo de processamento, tais como filtragens por convolução foram migradas para uma implementação em hardware do processo, mapeando em um dispositivo de lógica programável a síntese lógica da descrição de hardware (VHDL - Very high speed integrated circuit Hardware Description Language), no intuito de satisfazer os requisitos temporais do sistema

AutoCAD, Zemax Optic Studio 15, and Interactive Data Language (IDL) with the Proper Library are used to computationally model and test a diffractive mask (DiM) suitable for use in the Gemini Multi-Conjugate Adaptive Optics System (GeMS) on the Gemini South Telescope. Systematic errors in telescope imagery are produced when the light travels through the adaptive optics system of the telescope. DiM is a transparent, flat optic with a pattern of miniscule dots lithographically applied to it. It is added ahead of the adaptive optics system in the telescope in order to produce diffraction spots that will encode systematic errors in the optics after it. Once these errors are encoded, they can be corrected for. DiM will allow for more accurate measurements in astrometry and thus improve exoplanet detection. The mechanics and physical attributes of the DiM are modeled in AutoCAD. Zemax models the ray propagation of point sources of light through the telescope. IDL and Proper simulate the wavefront and image results of the telescope. Aberrations are added to the Zemax and IDL models to test how the diffraction spots from the DiM change in the final images. Based on the Zemax and IDL results, the diffraction spots are able to encode the systematic aberrations.