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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.
141

Experimentální práce s POF - polymerová optická vlákna / Experimental work with POF - Polymer optical fibers

Doležal, Ondřej January 2015 (has links)
In this diploma thesis, the reader is familiarized with polymer optical fiber (POF). Firstly is mentioned theoretical background of optical fibers and optical transmission. The following are the basic properties and significant parameters of POF, a more detailed description of each type POF and their essential advantages and disadvantages in comparison with established optical fibers based on glass. The next chapter describes the area of practical issues: working with fibers and fiber installation, as well as the available connectors and methods of measurement of POF. Closely are analyzed knowledge of the practice, including the utilize in the aerospace and automotive industries, as well as in industrial networks, access data networks and local area networks. The practical part includes the measurement of basic transmission and mechanical parameters, including analysis of the results. The conclusion summarizes all the findings and results of this work, including possible future developments.
142

Trendy přístupových sítí / Trends in Access Networks

Štěpán, Petr January 2014 (has links)
This work deals with the modern trends in FTTX, but mainly focuses on FTTH, who represents the connecting of fiber to the homes of the participants. Sum up the basic problems of communication on the optical fibre, followed by comparison with other types of access networks. Another part is the analysis of the problems of construction and a description of the optical network topologies and technologies used in FTTH. In following chapter are characterized active and passive elements forming AON and PON networks. Next part deals with the study of the most common services that can be on the optical access network to operate. They are mainly associated with the TriplePlay services. An integral part of the project is the study of management and supervision optical networks. In the main part is created real model situation where is the requirement for the creation of optical access networks with broadband of TriplePlay, followed by selection of appropriate options and detailed project with a selection of active and passive elements with economic balance.
143

Rozpoznávání textu z obrazových dat / Optical character recognition from image data

Marinič, Michal January 2014 (has links)
The thesis is concerned with optical character recognition from image data with different methods used for character classification. In the first theoretical part it focuses on explanation of all important parts of system for optical character recognition. The latter practical part of the thesis describes an example of image segmentation, the implementation of artificial neural networks for image recognition and create simple training set of data for the evaluation of the network. It also describes the process of training Tesseract tool and its implementation in a simple application EasyTessOCR for character recognition.
144

Reprodukovatelnost a přesnost měření polarizační vidové disperze / Reproducibility and accuracy of polarization mode dispersion measurements

Kováč, Filip January 2015 (has links)
Thesis is divided into two parts. The first part is written rather in theoretical way. It deals with general formation of the dispersion mathematically and verbally. It focuses on the chromatic and polarization mode dispersion. Different types of optical fibers for category G.65X are mentioned as well in connection with the ITU-T. Further attention is drawn first to compensation and then the measurement both of the mentioned dispersions. The thesis describes also analyzers and their main features. The second part is devoted to practical measurements of polarization mode dispersion. In the beginning there are described the components used for construction of the optical measurements and topologies. It is followed by an analysis of an each optical link. The results of these measurement methods and their mutual comparisons are at the end of this section. Measurements in temperature chamber is the subject of a further practical part, which from the beginning captures the essential features of the temperature chamber. This is followed by a description of the measurements, analyses and final valuation depending on the amount of polarization mode dispersion versus the temperature.
145

Modernizace páteřní sítě poskytovatele internetových služeb / Modernizing the Internet Service Provider´s Backbone

Nedbal, Tomáš January 2009 (has links)
The thesis is focused on the technical issues removal on the backbone of internet service provider, MX-NET Telekomunikace Ltd. After marketing research of impacts on client there will be determined the best alternative of solution, ensured the appropriate funding and organized the installation.
146

Porovnání deformací stanovených metodou konečných prvků a optickým měřícím zařízením / Comparison of strains determined by finite element method and by optical measurement system

Zajíček, Vít January 2011 (has links)
This thesis focuses on the comparison of numerical simulation and optical measurement of deformation of the turbinehousing made by Honeywell company. The numerical calculation performed by finite element method to simulate transient thermal load on the measured entity. Numerical result of the strain state of the body caused by temperature gradients. To verify the simulation is used an experimental digital correlation method VIC-3D. The thesis also mentioned the theoretical foundations of digital correlation methods and thermal analysis.
147

Elektrické, optické a senzorové vlastnosti organických polovodičů / Electrical, Optical and Sensoric Properties of Organic Semiconductors

Pochekailov, Sergii January 2009 (has links)
There is big interest in cheap, sensitive and selective gas sensors. In this work, substituted soluble phthalocyanines are proposed as a sensing materials for several gases. Optical, electrical and gas sensing properties of several phthalocyanines were studied and the mechanisms of their interaction with several analyte gases are described. It was found, that sulfo-substituted Pcs has good sensitivity to humidity. Sulfonamide-substituted phthalocyanines are promising for nitrogen dioxide and volatile organic compounds detection. tert-Butyl-substituted phthalocyanines are sensitive to NO2 under higher temperature and seems to be used for environmental monitoring. Commercial gas sensors for NO2, ethanol and humidity were successfully created.
148

Prostorové dělení optických svazků / Spatial Division of Optical Beams

Hampl, Martin January 2009 (has links)
The dissertation thesis deals with a free space optical links, especially is focused directly to the transmission optical beams. The influence of environmental conditions like atmospheric turbulence, buildings movement and vibration is described. As a possibility to reduce these undesirable influences, the generation of the transmission beam by the help of the two-mode optical fiber is proposed. A possibility to drive the shape of the resulting transmission beam by means of the change of power ration of individual modes in fiber is described. The coherence features of the proposed beam are analyzed considering the possibility to reduce the influence of atmospheric turbulence. In the thesis there are introduced beam quality parameters that enable to evaluate the quality of the optical beam for the free space optical link. These parameters give the relationship between the shape of the optical beam and the power balance of the optical link and the statistical evaluation of the optical link.
149

Nové přístupy pro optická měření elektrické aktivity myokardu / New Approaches in Cardiac Optical Mapping

Švrček, Martin January 2011 (has links)
This dissertation deals with new approaches in cardiac optical mapping. The principle of cardiac optical mapping as well as the current research in this field was described. The new measurement system was developed and its characteristics presented. The system design allows epicardial and endocardial mapping, employing new ratiometric techniques in 2D acquisition and simultaneous electrical and optical mapping. The measured characteristics of fluorescent dye di-4-ANEPPSS were presented. The relation between movement and consequent motion artifacts is well described. Several new approaches in signal processing were proposed, including new ratiometry technique and using image registration to suppress motion artifacts. The algorithm for elastic image registration of optical signals and innovative method for verification of registration process were presented. Application of all proposed approaches and its results are included and discussed.
150

Detekce a rozpoznání registrační značky vozidla pro analýzu dopravy / License Plate Detection and Recognition for Traffic Analysis

Černá, Tereza January 2015 (has links)
This thesis describes the design and development of a system for detection and recognition of license plates. The work is divided into three basic parts: licence plates detection, finding of character positions and optical character recognition. To fullfill the goal of this work, a new dataset was taken. It contains 2814 license plates used for training classifiers and 2620 plates to evaluate the success rate of the system. Cascade Classifier was used to train detector of licence plates, which has success rate up to 97.8 %. After that, pozitions of individual characters were searched in detected pozitions of licence plates. If there was no character found, detected pozition was not the licence plate. Success rate of licence plates detection with all the characters found is up to 88.5 %. Character recognition is performed by SVM classifier. The system detects successfully with no errors up to 97.7 % of all licence plates.

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