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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.
211

Kalibrace geometrie vln vytvořených na matrici(lisovnici) z plechu / Sizing of the waves geometrical parameters fabricated on the sheet metal die

Stupárek, Daniel January 2010 (has links)
This thesis approaches the problem of the return of the original geometric shape of the wave which is created on die panels. Die is used as a structural feature of the fiber-cement roofing material in its shipment in the production line. Based on the study of the theory of cold formed sheet metal determine the actual status in the plant. The method of calibration was designed from the collected informations about the original manufacturer of sheet metal panels. Under this proposal and calculation of the required forming power for the recalibration wave in the factory device for the die calibration was designed and constructed. Equipment calibration was performed on two types of corrugated panels and the result fulfilled the theoretical assumptions. In conclusion is processed technological-economic evaluation and the accompanying drawings.
212

Studium plazmatu v zařízeních typu tokamak spektroskopickými metodami / Study of plasma in tokamak-type devices with spectroscopic methods

Naydenkova, Diana January 2017 (has links)
In Tokamak department of Institute of Plasma Physics, radiation of high-temperature plasma is investigated using spectroscopic methods in visible, ultraviolet and infrared regions. The radiation gives information regarding tokamak plasma parameters and their changes, which is necessary for future realization of fusion reactor. In the frame of this doctoral thesis the development of spectroscopic diagnostics for observing of plasma radiation and its temporal evolution in COMPASS tokamak was performed. The absolute calibration of developed systems in order to recalculate measured signal to units of radiation was done. The sources of imprecisions of absolute measurements in tokamak conditions are properly discussed in the first part of the dissertation. Plasma radiation in the range 257-1083 nm was measured and interpreted using NIST database and FLYCHK code. Ion density for the most significant impurities was estimated. IDL code for effective ion charge estimation as a ratio of real and hydrogen plasma Bremsstrahlung radiation near 523 nm was developed. Profiles of electron density and temperature measured by Thomson scattering system were used for hydrogen plasma Bremsstrahlung radiation calculations. The example of applying of spectroscopic data for studying of COMPASS plasma heating using neutral beam...
213

Scatterometer Cross Calibration Using Volume Scattering Models for Amazon Rainforest Canopies

Chrisney, Evan Neil 03 December 2019 (has links)
Spaceborne scatterometers have measured the normalized radar cross section (RCS) of the earth's surface for several decades. Two frequencies, C- and Ku-band, have been used in designing scatterometers, such as with the Ku-band NASA Scatterometer (NSCAT) and the C-band Advanced Scatterometer (ASCAT). The scatterometer data record between C- and Ku-band has been disjoint for several decades due to the difficulties in cross calibration of sensors that operate at different frequencies and incidence angles. A model for volume scattering over the Amazon rainforest canopy that includes both the incidence angle and frequency dependence is developed to overcome this challenge in cross calibration. Several models exist for the σ0 incidence angle dependence, however, none of them are based on backscatter physics. This thesis develops a volume scattering model from a simple EM scattering model for cultural vegetation canopies and applies it to the volume scattering of the Amazon rainforest. It is shown that this model has lower variance than previously used models for the incidence angle dependence of σ0, and also enables normalization of σ0 with respect to the incidence angle. In addition, the frequency dependence of σ0 is discovered to be quite sensitive at Ku-band due to the distribution of leaf sizes in the Amazon rainforest. This may limit the accuracy of the model of the frequency dependence of σ0. Although the proposed frequency dependence model may be limited for cross calibrating between C- and Ku-band, it provides the groundwork for future studies.
214

The `Electric' Pascal: Absolute and Dynamic Calibration Techniques

Dillon, Brandon James 29 October 2013 (has links)
This article describes a pressure generation technique that has been applied to the task of calibrating hydraulic pressure transducers. The technique combines principles given by the Lorentz Force and Faraday's Law of Induction to generate a hydrostatic pressure within a cavity. The time history of this pressure is given by the device without reliance on a reference transducer or knowledge of: the local gravity; thermodynamic properties of the working fluid; or acceleration of the cavity. In this way, the Pascal can be defined by reference only to the standards of the Amp, the Volt, the Meter, and -- in the case of time varying pressure -- the Second. Using this technique, a prototype device has been developed using commonly available tooling and can generate pressures in the range of 0.1 to 600 Pa with relative errors of 1.5%. / Master of Science
215

Camera Calibration Based on Mirror Reflections / 鏡面反射を利用したカメラキャリブレーション

Takahashi, Kosuke 26 March 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第21206号 / 情博第659号 / 新制||情||114(附属図書館) / 京都大学大学院情報学研究科知能情報学専攻 / (主査)講師 延原 章平, 教授 美濃 導彦, 教授 松田 哲也 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM
216

Calibration and Evaluation of Low-Cost Optical Dust Sensors and Monitors

Zervaki, Orthodoxia January 2018 (has links)
No description available.
217

The assessment of an SSDL calibration facility for computed tomography ionization chambers.

Msimang, Zakithi Lungile Mpumelelo 14 November 2006 (has links)
Student Number : 8802466H - MSc research report - School of Physics - Faculty of Science / Medical ionising radiation sources give by far the largest contribution to the population dose from man-made sources. About 90% of this contribution is due to x-ray diagnostic procedures. Doses from diagnostic radiology procedures are nevertheless small and usually do not approach thresholds for deterministic effects. However, they must be accurately determined in order to maintain a reasonable balance between image quality and patient exposure. There is, thus, a need to establish quality assurance for diagnostic procedures that will provide the required clinical information in its optimal form and with minimum dose to the patient. In order to achieve this, dose measurements must be reproducible and the uncertainties associated with that measurement should be known. One of key factors for ensuring that appropriate levels of accuracy and long-term reproducibility of dose measurements are maintained is a calibration of the measuring equipment. The IEC (International Electrotechnical Commission) issued a standard IEC 61267 that deals with methods for generating radiation beams with radiation conditions which can be used under test conditions typically found in test laboratories for the determination of characteristics of medical diagnostic X-ray equipment. The document is currently being revised and publication of the new version is expected soon. Standard radiation qualities were established at a laboratory following the new IEC 61267 standard. Radiation qualities that characterize radiation beams emerging from the X-ray target (RQR qualities) were established. They were further filtered by Copper to obtain RQT beam qualities that simulate those used in Computed Tomography (CT). The spatial uniformity of a commercial CT dosimeter was then determined.
218

Towards System Agnostic Calibration of Optical See-Through Head-Mounted Displays for Augmented Reality

Moser, Kenneth R 12 August 2016 (has links)
This dissertation examines the developments and progress of spatial calibration procedures for Optical See-Through (OST) Head-Mounted Display (HMD) devices for visual Augmented Reality (AR) applications. Rapid developments in commercial AR systems have created an explosion of OST device options for not only research and industrial purposes, but also the consumer market as well. This expansion in hardware availability is equally matched by a need for intuitive standardized calibration procedures that are not only easily completed by novice users, but which are also readily applicable across the largest range of hardware options. This demand for robust uniform calibration schemes is the driving motive behind the original contributions offered within this work. A review of prior surveys and canonical description for AR and OST display developments is provided before narrowing the contextual scope to the research questions evolving within the calibration domain. Both established and state of the art calibration techniques and their general implementations are explored, along with prior user study assessments and the prevailing evaluation metrics and practices employed within. The original contributions begin with a user study evaluation comparing and contrasting the accuracy and precision of an established manual calibration method against a state of the art semi-automatic technique. This is the first formal evaluation of any non-manual approach and provides insight into the current usability limitations of present techniques and the complexities of next generation methods yet to be solved. The second study investigates the viability of a user-centric approach to OST HMD calibration through novel adaptation of manual calibration to consumer level hardware. Additional contributions describe the development of a complete demonstration application incorporating user-centric methods, a novel strategy for visualizing both calibration results and registration error from the user’s perspective, as well as a robust intuitive presentation style for binocular manual calibration. The final study provides further investigation into the accuracy differences observed between user-centric and environment-centric methodologies. The dissertation concludes with a summarization of the contribution outcomes and their impact on existing AR systems and research endeavors, as well as a short look ahead into future extensions and paths that continued calibration research should explore.
219

The calibration of a robotic workstation /

Thong, Woon Kong. January 1986 (has links)
No description available.
220

In situ calibration for load cells in bipedal 3D printed robot utilizing Computer-Aided Design model

Le, Tung Xuan 07 August 2023 (has links)
Load cells are very important components in a robot system. They help the robot to get feedback from the environment around it and generate control signals accordingly. However, like every other sensor, load cells need to be calibrated over time to maintain their accuracy and precision. In the current method, they need to be detached from the robot. Then known weights are hung below the load cells to get the raw signal from the load cells. These two types of values will then be used to generate the equations that convert the raw signal to the force values. This is a challenge as not many robots are maintenance-friendly so detaching the load cells can take a lot of time, not to mention the process can damage the load cells if not conducted carefully. This research project utilizes mechanical simulation to calculate the known force values acting on the load cells without taking them out of the robot system. Then these force values are used for the calibration process. In this thesis, the in situ calibration method will be conducted on the actuator-controlled pendulum, and a bipedal robot when it is hanging on the gantry and standing on the ground. Also, since mechanical simulation requires a lot of computational power, a geometry simplification method will also be introduced so this in situ calibration method can be used for ordinary personal computers. The results show that the new calibration method is easy to work with, the force values still meet the requirements for calibration, and the computer only needs 10-12 seconds to run each simulation. / Master of Science / A robotic system usually need the load cell to generate the correct control signal. However, the load cell needs to be calibrated over time for maintenance. The current calibration method requires the load cell to be detached from the robot so the user can apply known forces to the load cell. This thesis introduces an in situ calibration method that can calculate forces that are applied to the load cell so the user does not need to detach the load cell from the robot. An optimization method is also introduced to make the calibration process can be done on an ordinary personal computer.

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