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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.
1

Investigation of finite-difference frequency-domain method in a mixed coordinate system and its applications

Shih, Chien-Hua 15 July 2008 (has links)
none
2

Analysis of the Out-of-Control Falling Leaf Motion using a Rotational Axis Coordinate System

Lluch, Daniel Cutuli 08 October 1998 (has links)
The realm of aircraft flight dynamics analysis reaches from local static stability to global dynamic behavior. It includes aircraft performance issues as well as structural concerns. In the particular aspect of dynamic motions of an aircraft and how we understand them, an alternate coordinate system will be introduced that will lend insight and simplification into the understanding of these dynamic motions. The main contribution of this coordinate system is that one can easily visualize how the instantaneous velocity vector relates to the instantaneous rotation vector, the angular rate vector of the aircraft. The out-of-control motion known as the Falling Leaf will be considered under the light of this new coordinate system. This motion is not well understood and can lead to loss of the aircraft and crew. Design guidelines will be presented to predict amplitude and frequency of the Falling Leaf. NOTE: (12/2009) An updated copy of this ETD was added after there were patron reports of problems with the file. / Master of Science
3

System for Tracking of Surgical Tools and Assessment of Surgical Skills Using Continuously Adaptive Mean Shift Methodology

Manat, Namith N. 01 January 2005 (has links)
A tracking system that serves as a tool for tracking the movement of surgical instruments has been developed. The system tracks color markers on the surgical instruments. The Continuously Adaptive Mean Shift (CAMSHIFT) methodology was employed for tool tracking and a total distance traversed by the surgical instrument of interest was calculated. Two cameras were used to record the motion of the tool and the software developed was used to track the movement of markers on the tools over subsequent frames. The information thus derived from the two views of cameras was used to calculate the three dimensional coordinates of the location of the marker on the instrument and subsequently the distance traversed. MATLAB, which is a commercial software package, was used to implement the tool tracking algorithm and for developing the GUI (Graphic User Interface). Data was collected using Commercial off the shelf (COTS) camera hardware and processing was done on a 2.2 GHz, 512 MB RAM Intel Pentium 4 computer.
4

Localization of Human Pelvis Anatomical Coordinate System Using Ultrasound Registration to Statistical Shape Model

GHANAVATI, SAHAR 24 August 2010 (has links)
Total Hip Replacement (THR) has become a common surgical procedure in recent years, due to the increase in the aging population with hip osteoarthritis. Identifying the proper orientation of the pelvis is a critical step in accurate placement of the femur prosthesis in the acetabulum in THR. The general approach to localize the orientation of the pelvic anatomical coordinate system (PaCS) is to use intra-operative X-ray fluoroscopy in a specialized interventional radiology facility to guide the procedure. Employing intra-operative ultrasound (US) imaging fused with pre-operative CT scan or fluoroscopy imaging was proposed to eliminate the ionizing radiation of intra-operative X-ray to the patient and the need for radiology facilities in the OR. However, the use of pre-operative imaging exposes patients to accumulative ionizing radiation which is desirable to be eliminated. In this thesis, I propose to replace pre-operative imaging with a statistical shape model (SSM) of the pelvis which is constructed from CT images of patients. An automatic deformable registration of a pelvis anatomical shape model to a sparse set of 2D ultrasound images of the pelvis is presented in order to localize the PaCS. In this registration technique, a set of 2D slices are extracted from the pelvic shape model, based on the approximate location and orientation of a corresponding 2D ultrasound image. The comparison of the shape model slices and ultrasound images is made possible by using an ultrasound simulation technique and a correlation-based similarity metric. During the registration, an instance of the shape model is generated that best matches the ultrasound data. I demonstrate the feasibility of our proposed approach in localizing the PaCS on four patient phantoms and on data from two male human cadavers. None of the test data sets were included in the SSM generation. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2010-08-23 17:57:24.708
5

極座標による心筋Tl-201Bull's-eye表示の試み

MIYABO, Susumu, NAKAMURA, Toru, ISHII, Yasushi, MISAWA, Toshihiro, LEE, Joan Dae, MAEDA, Hisatoshi, 宮保, 進, 中村, 徹, 石井, 靖, 三沢, 利博, 李, 鐘大, 前田, 尚利 08 1900 (has links)
No description available.
6

In Vitro Biomechanical Characterization of Tibiofemoral Rotations and Translations Following Distal Bony Realignment

Mani, Saandeep 18 August 2010 (has links)
No description available.
7

A Numerical Model for Oil/water Separation from an Accelerating Oil-coated Solid Particle

Abbas-Pour, Nima 20 November 2013 (has links)
A computational fluid dynamics model has been developed to examine the separation of an oil film from a spherical oil-coated particle falling through quiescent water due to gravity. Using this model, the separation process was studied as a function of the viscosity ratio of oil to water, R, and the ratio of viscous forces to surface tension, represented by the Capillary number Ca. The governing equations of this flow-induced motion are derived in a non-inertial spherical coordinate system, and discretized using a finite volume approach. The Volume-of-Fluid method is used to capture the oil/water interface. The model predicts two mechanisms for oil separation: at R less than 1, the shear difference between the particle/oil interface and the oil/water interface is not significant and Ca determines whether separation occurs or not; at R larger than 1, the shear difference is considerable, and the Ca effect becomes less dominant.
8

A Numerical Model for Oil/water Separation from an Accelerating Oil-coated Solid Particle

Abbas-Pour, Nima 20 November 2013 (has links)
A computational fluid dynamics model has been developed to examine the separation of an oil film from a spherical oil-coated particle falling through quiescent water due to gravity. Using this model, the separation process was studied as a function of the viscosity ratio of oil to water, R, and the ratio of viscous forces to surface tension, represented by the Capillary number Ca. The governing equations of this flow-induced motion are derived in a non-inertial spherical coordinate system, and discretized using a finite volume approach. The Volume-of-Fluid method is used to capture the oil/water interface. The model predicts two mechanisms for oil separation: at R less than 1, the shear difference between the particle/oil interface and the oil/water interface is not significant and Ca determines whether separation occurs or not; at R larger than 1, the shear difference is considerable, and the Ca effect becomes less dominant.
9

Coordinate Systems For A Naval Virtual Environment

Asli, Kilic 01 September 2005 (has links) (PDF)
The purpose of this thesis is implementing World Geodetic System (WGS) for Naval Surface Tactical Maneuvering Simulation System (NSTMSS), a High Level Architecture (HLA) based naval simulation, and also implementing body coordinate system for the ships of NSTMSS and its combination with WGS so that NSTMSS can be more accurate, and new ship dynamics models can be integrated to the NSTMSS environment more easily. To improve the coordinate system of NSTMSS these methods were used / World Geodetic System - 1984 (WGS 84) was chosen as the reference system of new coordinate system of NSTMSS and coordinates were transformed to Universal Transverse Mercator (UTM) Coordinate System. Also, the terrains which NSTMSS uses created in OpenFlight (FLT) format with UTM map projection method. In addition to this, Ship Body Coordinate System was implemented as a Cartesian coordinate system. This thesis has achieved improved coordinate systems for the NSTMSS environment to increase the realism of the simulation.
10

Mapeamento e documentação de feições visuais diagnósticas para interpretação em sistema baseado em conhecimento no domínio da petrografia / The diagnostic visual feature mapping and documentation in a knowledge-base system for interpretation in the Petrographic domain

Victoreti, Felipe Ingletto January 2007 (has links)
Nos domínios visuais, interpretações são iniciadas pela identificação de feições em imagens que irão, posteriormente, dar suporte aos processos mais abstratos de inferência. Para desenvolver sistemas de conhecimento neste tipo de domínio é necessário buscar a melhor representação do conhecimento visual para ser utilizado pelos métodos de inferência. A representação em formato simbólico deste conhecimento auxilia na captura do conhecimento implícito presente em imagens, permitindo seu uso nos processos de raciocínio, mesmo aceitando que parte desse conhecimento não é externalizado e, em conseqüência, não poderá ser representado adequadamente. Estudos recentes têm utilizado anotação de imagens como uma maneira capaz de auxiliar na explicitação do conhecimento, ampliando a expressividade dos formalismos de representação e permitindo o registro das informações associadas às imagens. Embora anotações de imagens flexibilizem a captura do conhecimento, ontologias são associadas às anotações para garantir a formalização do conhecimento nas imagens, suprindo os termos de domínio que podem ser usados para anotar e auxiliar a uniformização da linguagem nas consultas. O objetivo desse trabalho é capturar e documentar o conhecimento visual que dá suporte à inferência nas tarefas de interpretações. Nesse trabalho é elaborada uma maneira de identificar objetos em imagens que contenham feições diagnósticas através da utilização de uma ontologia de domínio pré-existente. Essa identificação de objetos é explorada para permitir a localização física de uma determinada feição em um objeto real. O resultado disso é a identificação de feições em uma imagem tendo-se um referencial de posição segundo um sistema de coordenadas espacial, possibilitando o seu re-posicionamento. O trabalho ainda explora recursos para a melhor utilização de informações relacionadas a uma imagem. Dessa forma, serve de documentação auxiliar para prover diferencial em interpretações. O domínio de aplicação deste trabalho é a Petrografia Sedimentar que tem como uma das tarefas a descrição quantitativa e qualitativa dos minerais que compõem uma amostra de rocha, visando a análise do potencial de um reservatório de petróleo. As informações são visualizadas em uma amostra de rocha e, assim, um especialista toma decisões quanto à viabilidade de exploração do reservatório. Esse modelo foi validado através da implementação de um módulo de anotação de imagem e de referenciamento de objetos, juntamente com um hardware. O processo de descrição de amostra de rocha é detalhado para se explorar o conhecimento em imagens com a precisão da localização dos objetos nela identificados. Essa abordagem complementa os modelos de representação simbólica, que normalmente são insuficientes para capturar a semântica das feições que dão suporte a inferência em domínios visuais. / Problem solvers in visual domains apply image interpretation to extract evidences to support the reasoning process in the search of solution. In order to develop knowledge systems in this kind of domain, it is necessary to represent the knowledge that is extracted from the scenes in the domain in such way that can be used by the inference methods. The symbolic representation formalisms help in shading light on the implicit knowledge embodied in images, allowing its use in reasoning processes, even accepting that part of this knowledge can not be properly expressed by the experts and, in consequence, it is never going to be adequately represented in knowledge models. Some studies use image annotation to extend the semantic capture of the visual knowledge beyond the expressiveness of representation formalisms, allowing that additional content could be described and stored with the images. Although the annotation is a more flexible way of capturing knowledge, ontologies are used along with it to guarantee the formalization of the knowledge annotated in the images, supplying the domain terms that can be used in the annotation process and helping the uniformization of the language and further consultation. The goal of this work is capturing and documenting the visual knowledge that supports inference on interpretation tasks. The work offer a way of identifying objects in images that correspond to diagnostic features and describing them with the support of a pre-existent domain ontology. The object identification is associated to the physical location of the feature in the real object, with the help of a hardware appliance. The result is the feature identification in the image with the reference of its position in a system of spatial coordinates. The work also explores multimedia resources for the best use of information associated to the image, providing an extra-support for knowledge documentation for interpretation tasks. The application domain of this work is the sedimentary petrography, the formal description of rocks in the scope of Petrological studies. The task in focus is the compositional description of minerals in a rock sample, both in qualitative and quantitative way, in order to evaluate the potential of a petroleum reservoir. Several aspects of the rock are studied by the geologist to suggest better techniques for exploration and production of oil fields. The approach defined in this project was validated through the implementation of an image annotation and referencing modules associated to microscope stage appliance that allows the computer to control the movement of the stage during the description process. The whole process of rock sample analysis using the software and the hardware is detailed in order to expose the visual knowledge and its physical position in the rock sample. This approach complements the symbolic representation models that are usually insufficient to capture the semantic of diagnostic features that support reasoning in visual domains.

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