• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 163
  • 17
  • 2
  • Tagged with
  • 182
  • 155
  • 53
  • 51
  • 26
  • 25
  • 24
  • 22
  • 18
  • 15
  • 15
  • 15
  • 15
  • 14
  • 14
  • 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.
81

Měření difuzně odrazných povrchů pomocí vírové topografické mikroskopie / Measurement of diffusely reflecting surfaces using vortex topographic microscopy

Pola, Tomáš January 2020 (has links)
This thesis describes an innovative method for topographic measurement of diffuse surfaces. Tested surface is measured indirectly using nanoparticles distributed across the studied area. An image of every particle is captured by CCD camera as a double helix point spread function whose angular rotation corresponds to local surface height. Used point spread function is the result of an interference of non-diffracting vortex beams that are formed by a spiral phase mask from light originating from a nanoparticle. Diploma thesis presents an overview of current techniques for surface topography measurement. Next, working principle of proposed method is described and its experimental application is discussed. An influence of signal-to-noise ratio and image sampling on reconstruction precision is studied using numerical simulations and, as a result, optimal experimental parameters are proposed. Practical potential of the method is demonstrated by 3D reconstruction of planar and spherical surfaces in the depth range of up to 9 times the depth of focus of used microscope objective.
82

Návrh postupu kontroly vybraných součástí revolveru / Design of inspection procedure for selected revolver components

Úlehlová, Eva January 2020 (has links)
The goal of this master’s thesis was design of the inspection procedure for hammer and trigger of the specific revolver model. Thesis was developed in cooperation with the manufacturer of the revolvers. The theoretical part deals with the MSA methodology, which is used to assess acceptability of measurement systems. The practical part describes the current measurement system and performs gage repeatability and reproducibility study. It was confirmed that the current measurement system requires improvement. Subsequently coordinate systems were designed, based on functional features of the hammer and trigger. Automated optical measurements, based on the coordinate systems, were performed. The results from these measurements were again assessed by the gage R&R study. The analysis confirmed improvement of acceptability of the designed measurement systems. Based on these results, it is recommended to apply suggested procedures in practice. Results and recommendations of this master’s thesis can contribute to develop metrology in the company and improve the existing measurement system.
83

Právní aspekty boje proti počítačové trestné činnosti / Legal Aspects of Fighting Cybercrime

Dostál, Otto January 2020 (has links)
The thesis deals with the topic of computer crime. Foremost, it demonstrates on an example of the operation of a medical image information processing system some selected aspects of this issue. It shows that it is always necessary to monitor the current state of the technical knowledge at the time, but also the need of addressing the issue within the corresponding legal limits. The thesis presents criminal law reality as a complex system. The links between different parts of the system are examined, and possible shortcomings are considered. The legal instruments and legal limits of the procedures that can be used against cybercrime are evaluated. The thesis focuses especially on the issue of obtaining evidence under the Czech Criminal Procedure Code. It presents a proposal on how to understand individual procedural legal institutes and for what purposes and how to use them. Consequently it suggests legal procedures for specific selected practical situations.
84

Posouzení spolehlivosti procesu balení optických kabelů / Reliability assessing of the fiber optic packaging process

Plodková, Zuzana January 2021 (has links)
The diploma thesis deals with the assessment of the reliability of processes at the packaging center in the company CommScope Czech Republic s.r.o. The first part of the work is research about options for quality management using ISO 9000 standards, but also TQM approaches. At the same time, methods and analytical techniques are discussed, which will be further used in the practical part of this thesis. The following section introduces CommScope Inc. and its main product - optical fiber. The practical part contains an introduction to the packaging center and its processes, it also describes the analysis of the reliability of the original state and proposals for corrective measures that were designed within the Kaizen event. The rest of the work is then devoted to the implementation of the proposed changes and their economic assessment. Finally, an evaluation of the methods used, the results achieved and other recommendations are given.
85

Stanovení nejistoty měření optického měřicí stroje pomocí laserinterferometru / Determination of measurement uncertainty of the optical measuring machine using a laser interferometer

Fulová, Silvia January 2021 (has links)
This final thesis is dealing with stating uncertainty of optical measuring device Micro-Vu Sol 311, which is located at Faculty of mechanical engineering in Brno. Overview of coordinate measuring machines (CMM for short) and analyzed present status of optical CMM is in summation. This part also includes basic metrology concepts and methodology of determination of uncertainty of measuring instrument. Content of following parts of thesis is detailed description of Micro-Vu SOL 311 machine and etalons that were used in determination of enhanced uncertainty of measurement such as gage blocks, laser interferometer and glass scale. Last part of this thesis includes summary of achieved results and recommendations for practice.
86

Pracoviště pro optickou interferometrii / Workstation for optical interferometry

Blecha, Martin January 2008 (has links)
This thesis is specialized on composition of workplace for experiments flowing from optical interferometry. Here are described laboratory exercise servant for demonstration basic principles of interferometry. In more details is described method measurement of height profile objects with method white light interferometry.
87

Vliv kvality optických konektorů na přenos / Effect of optical connectors quality on transmission

Bernkopf, Miroslav January 2008 (has links)
This diploma thesis deals with optic fiber connectors and their influence on transmissions realized via fiber optics. Optical fibers and lightguides play the key role in telecommunications because of constant demands of higher bandwidth and data rates. Original metalic wires do not meet market requirements and so the fiber optics are more and more being used. There are various types of fibers and there are also many ways of connections. This work deals with demountable way of connection – optical connectors, which have the biggest influence on a total attenuation and route length. Connector has to meet various requirements such as cleannes, quality, mechanical construction and ferrule polishing.
88

3D triangulační technika rekonstrukce objektů / 3D triangulation technique for object reconstruction

Pospíšil, Petr January 2009 (has links)
My paper work deals with the 3D active triangular method of building reconstruction. First, there was a measuring triangular system created. Then the way of its automatic calibration was proposed and consequently also performed. Also algorithms for the automatic detection of the sample projected were proposed. Algoriths were presented with several sample buildings. The result of these algorithms are 3D models of individual buildings. In the end achieved results nd restrictions of the system proposed were assessed.
89

Vliv kvality mechanických prací na optický přenos / Effects of mechanical doings on optical data transport

Tihlařík, Tomáš January 2009 (has links)
This master´s thesis deals with of human factor impact on optical fibers manipulation. It describes types and methods used for splicing and placing optical fibers and optical cables. These methods are specified in the chapters; their application in different environments and conditions is accentuated. This paper presents splicing optical fibers. It emphasizes problems which can occur if proper procedures aren´t kept or if improper device is used. In the thesis there is the chapter dealing with problems which can arise during splicing optical fibers - these negative influences are evaluated with educational equipments EF-970-01 PLASTIC by the company MIKROKOM, s.r.o. Another aim of the work is to describe mechanical optical fiber splice 3MTM FibrlokTM. This kind of device was lent for testing optical fibers multiple splicing. It was tested under extreme conditions. Statistically processed values of insertion loss and splice reflectance, measured by OTDR are the results of the test. Comparing measured values, technical report ones, regarding for usage in practice, there is a possibility of 75 multiple reusing of the mechanical optical fiber splice. The prediction of magnitude insertion loss, calculated for thousands splice cycles follows. The next part of the work deals with fusion splices and contains comparison of splices made with two cleavers: CORNING LWL-TRENNGERAT S46999-M9-D12 and the later model - Fitel S325A cleaver. The result is that older S46999-M9-D12 model gained lower attenuation. The results of both previous measurements are influenced by human factor. It appears at mechanical optical fiber splices as growing fluctuate of insertion losses and as the unequal attenuation fusion splices at tested cleavers.
90

PMD - polarizační vidová disperze a vliv na přenos / PMD - polarization mode dispersion and its effects on data transport

Trávníček, Pavel January 2009 (has links)
My graduation thesis is concerned with the effect of polarization mode dispersion on transmitted signal by optical line. It describes external and internal causes of origination of polarization mode dispersion. On the basis of these effects there is a differential group delay (DGD). It is the time delay in meantime within individual modes. DGD results in a time extension of impulsion and limitation of maximum bit rate. This thesis contains localization methods of part of gossamer filament with increased value of PMD by POTDR method. This method is based on the principium of back dispersion and its modifications SOP a DOP. Very important chapter of this thesis is the measurement of the polarization mode dispersion. There are described methods of PMD measurement. It is the interferometric and polarimetric method and the method of state of polarization. The major part of this thesis is about the reduction of polarization mode dispersion effect. This part is divided into two parts. First part is about the methods of PMD effect reduction and the second one is about the PMD compensation. The discrepancy between these two parts is the reduction way of PMD effect on transmitted channel. The compensation use the compensation components inserted into the transmission path. By PMD reduction methods we can solve the problems from the view of changing of fibre or all cable. For better understanding of polarization mode dispersion effect there are simulated 4 optical lanes of various parameters. The simulation output is the eye diagram which provides the view at results of transmission lane. In the final part there is the evaluation of measured parameters of optical lanes simulated in a laboratory.

Page generated in 0.3854 seconds