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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.
241

Cálculo das sequências positiva e negativa em tempo real a partir do produto escalar de vetores espaciais: aplicações em compensadores de perturbações na rede. / Calculation of positive and negative sequences in real time by using space vectors dot products: applications to grid disturbances compensators.

Carvalho, Kelly Caroline Mingorancia de 02 February 2015 (has links)
O presente trabalho pretende aplicar o método de cálculo de componentes simétricas por produtos escalares de vetores espaciais para o cálculo dos sinais de referência de compensadores de perturbação. Outras metodologias de cálculo de corrente de referência são apresentadas, analisadas e comparadas com o método implementado. Uma revisão de vetores espaciais nos sistemas abc e 0 é feita para auxílio da explicação do método de extração de componentes simétricas. O método é inicialmente apresentado de forma generalista, de modo que é realizado o cálculo de componentes de sequência positiva, negativa e zero para um harmônico de ordem h. A autora apresenta algoritmos de exemplos práticos para uso em cálculo de corrente de referência incluindo as compensações de reativos da corrente fundamental, de harmônicos pré-selecionados e de desequilíbrios de carga. O método é analisado e validado por meio de simulações e resultados experimentais. / This work applies, for a disturbance compensator, a method for the calculation of the symmetrical components based on space vectors\' dot product. Other methods are presented, analyzed and compared with the proposed method. The symmetrical components calculation method is explained using a geometrical approach in abc and 0 basis. Initially, it is presented a general method that calculates the hth order positive, negative and zero sequence components of a current or voltage signal. Then, practical examples are presented for current compensation, which includes: fundamental reactive current compensation, fundamental negative sequence compensation and pre-selected order harmonics compensation. The method is analyzed and validated by simulation and experimental results.
242

Kalibrace optických souřadnicových měřicích strojů GOM ATOS / Calibration of GOM ATOS optical coordinate measuring machines

Košťák, Ondřej January 2017 (has links)
This master’s thesis contains the basic division of 3D methods which are used for reconstruction of measured objects. Furthermore the types of structured light patterns used for 3D triangulation. It also contains a description of the construction and functions of GOM ATOS and TRITOP machines. Primarily the thesis deals with the calibration of these machines, the design of suitable materials standard of size and the internal calibration methodology used by ŠKODA AUTO a.s. The text also includes verification of the proposed calibration procedure in practice, proposal for determination of calibration uncertainties and recommendations for practice.
243

Využití souřadnicového měřicího stroje pro hodnocení kvality povrchu / Use of a coordiante measuring machine for surface quality evaluation

Vančurová, Martina January 2018 (has links)
This master’s thesis deals with the use of a coordinate measuring machine probe for surface texture evaluation. The thesis’ goals were to describe the Renishaw’s SFP2 probe, to analyze the measurement system of the probe and a common stylus instrument, to carry out a demonstrative measurement, to analyze measurement results and to give practical recommendations. The measurement system analysis of the SFP2 consists in the evaluation of minimal specification limits of selected roughness parameters, for which gauge capability can be proven. The analysis results are compared with the results of the measurement system analysis of the Surtronic 25 profilometer. The differences in the measuring processes of mentioned devices are demonstrated by surface texture inspection of torque converter body. For the measurement result analysis, uncertainties in the selected surface texture parameters are calculated in two ways. Finally, recommendations for the producer of the probe and for its users are worked out. The results of this thesis may contribute to a wider use of a coordinate measuring machines for surface quality evaluation.
244

Měřicí stanice v automatické obráběcí lince / Measuring stations in an automatic machining line

Fúsek, Jakub January 2018 (has links)
This master thesis deals with the use of measuring stations in an automatic machining lines. An overview of the methods of measuring engineering products in engineering practice with a focus on automation of measurement is described. The basic principles of function of these machines, their construction and materials are described. The largest part describes coordinate measuring machines, which continue to evolve and offer more and more possibilities for automatic measurement. The practical part is aimed at documenting the sample situation of measurements on this type of equipment and evaluating the possibility of its integration into the automatic machining line.
245

Ověření kvality katastrální mapy v katastrálním území Heroltice u Tišnova / Verification of quality of the cadastral map in cadastral unit Heroltice u Tišnova

Mrázková, Veronika January 2017 (has links)
This diploma thesis deals with verification of quality of the valid cadastral map in cadastral unit Heroltice u Tišnova. In pursuance of the thesis were surveyed primarily perceptible boundaries of the estates and perimeters of the buildings, and ascertained situation of the surveyed borders and the perimeters of the buildings was compared with situation of these depicted in the cadastral map pursuant to paragraph 13 and 15 of Annexe of the regulation no. 357/2013. Detected discrepancies are commented in the thesis and for specific cases are suggested specific solutions in order to achieve a proper condition of the situations. Outcome of the thesis may be used by relevant authority as a material for decision about implementation of the renewal of cadastral documentation using new mapping, or as a tool for owners of the estates for finding out what kind of discrepancies were detected on their estates and how they can rectify them.
246

Návrh interní metodiky pro měření výrobků a dílů na přístroji CMM UPMC Zeiss na pracovišti ČMI Brno / Proposal of internal methodology for measurement of products and parts on CMM UPMC Zeiss at CMI Brno

Hájková, Alena January 2020 (has links)
This diploma thesis deals with the proposal of internal methodology for measurement of products and parts on CMM UPMC Zeiss at CMI Brno. The first part of this work analyzes the current state of knowledge in the field of accurate measurement on coordinate measuring machines (CMM), which includes the definition of basic metrological concepts, methodology for determining and expressing uncertainties of measurement and a general description of CMM. The diploma thesis also contains a detailed description of the UPMC 850 CARAT S-ACC device from the company Zeiss and summarizes the requirements for the testing laboratory in accordance with the standard ČSN EN 17 025: 2018. The next part of the work is focused on defining and determining the measurement uncertainties for this CMM and on developing a testing procedure for measurements on this machine. The final part of this thesis summarizes the achieved results and recommendations for practice.
247

Kontrola kvality vstřikovaných plastů pomocí rentgenové počítačové tomografie / Quality control of injection molded plastics using X-ray computer tomography

Figar, Erik January 2020 (has links)
This Master‘s thesis deals with an aplication of computed tomography as the technology for quality control check of the plastic parts made by the injection molding process. The analyses were performed on two different types of plastic parts. These parts were delivered by two companies and they included the drawing documentation and CAD models. These plastic parts were analyzed according to their qualitative requirements. The analyses included evaluation of the geometric tolerances and porosity analysis with numerical and graphical evaluation. The new module for tool correction ,which is part of VGStudio Max, was tested on parts that were not in accordance with the required tolerances. Afterwards the new corrected geometries were exported. At the end of this Master’s thesis the porosity comparison was assessed between two different voxel resolution CT data. This comparison shows the complexity of this phenomenon and the importance of voxel resolution settings.
248

Metrologické charakteristiky měřícího ramene Hexagon Absolute Arm 83 / Metrological characteristics of the Hexagon´s Absolute Arm 83

Polášek, Ondřej January 2021 (has links)
This study analyzes current trends in metrology in the field of portable coordinate measuring machines and describes current methods for measurement system and process evaluation. Obtained knowledge is applied, in order to evaluate the capability of measurement system, which consists of articulated measurement arm and measurement standard.
249

Stanovení přesnosti měření souřadnicového měřicího stroje Zeiss UPMC Carat / Determining the measurement accuracy of a coordinate measuring machine Zeiss UPMC Carat

Kiška, Roman January 2021 (has links)
The aim of this diploma thesis is to create a comprehensive study of measurement accuracy of coordinate measuring machine (hereinafter CMM) Zeiss UPMC 850 Carat S-ACC (hereinafter Zeiss Carat) for the needs of the national metrological institute in Brno in accordance with ČSN EN ISO / IEC 17025 and the follow-up system standards of the ČSN EN ISO 10360 series. Additionally, it includes the creation of instructions for the calculation of measurement uncertainty, which will be put into effect in an accredited calibration laboratory. The first part of the work focuses on the description of the current state of knowledge and the definition of basic concepts in the field of metrology and accurate measurements on CMM. The second part describes the Zeiss Carat measuring machine, identifies the individual contributors to the resulting measurement uncertainty and defines the methodology for their quantification. The last part deals with the evaluation of calibration data and the calculation of the expanded measurement uncertainty of the Zeiss Carat instrument, which is used to quantify its accuracy.
250

Lokalizace stanic v síti Internet pomocí umělých souřadnicových systémů / Node localization on the Internet using artificial coordinate systems

Škvor, Martin January 2010 (has links)
This thesis is focused on methods for nodes localization in Internet using latency prediction in synthetic coordinates systems. Thesis also deal with methods, which latency prediction between nodes is based on other systems. Among such a methods particularly belongs King, which uses DNS (domain name service). Furthermore, thesis deal with relevance of overlay networks in latency prediction and their use for different services. Practical part of this thesis concentrates on method for latency prediction in synthetic coordinate system Global Network positioning. There were made two programs for counting coordinates of landmarks and hosts in this system. Measurements and calculations made in this thesis, are focused to determine accuracy of latency prediction of this method and their evaluation is made at the end of thesis.

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