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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.
271

Autonomous lung tumor and critical structure tracking using optical flow computation and neural network prediction

Teo, Peng (Troy) January 2012 (has links)
Objectives. The goal in radiotherapy is to deliver adequate radiation to the tumor volume while limiting damage to the surrounding healthy tissue. However, this goal is challenged by respiratory-induced motion. The objective of this work was to identify whether motion in electronic portal images can be tracked with an optical flow algorithm and whether a neural network can predict tumor motion. Methods. A multi-resolution optical flow algorithm that incorporates weighting based on the differences between image frames was used to automatically sample the vectors corresponding to the motion. The global motion was obtained by computing the average weighted mean from the set of vectors. The algorithm was evaluated using tumor trajectories taken from seven lung cancer patients, a 3D printed patient tumor and a virtual dynamic multi-leaf collimator (DMLC) system. The feasibility of detecting and tracking motion at the field edge was examined with a proof-of-concept implementation that included (1) an algorithm that detected local motion, and (2) a control algorithm that adapted the virtual MLC. To compensate for system latency, a generalized neural network, using both offline (treatment planning data) and online (during treatment delivery) learning, was implemented for tumor motion prediction. Results and Conclusions. The algorithm tracked the global motion of the target with an accuracy of around 0.5 mm. While the accuracy is similar to other methods, this approach does not require manual delineation of the target and can, therefore, provide real-time autonomous motion estimation during treatment. Motion at the treatment field edge was tracked with an accuracy of -0.4 ± 0.3 mm. This proof-of-concept simulation demonstrated that it is possible to adapt MLC leaves based on the motion detected at the field edges. Unplanned intrusions of external organs-at-risk could be shielded. A generalized network with a prediction error of 0.59 mm, and a shorter initial learning period (compared to previous studies) was achieved. This network may be used as a plug-and-play predictor in which tumor position could be predicted at the start of treatment and the need for pretreatment data and optimization for individual patients may be avoided. / February 2017
272

The Application of Guided Mental Imagery as an Instructional Strategy

Burns, Frances D. 05 1900 (has links)
The primary purpose of this study was to compare regular classroom instruction which used Guided Mental Imagery (GMI) to a non-GMI teaching method. This comparison was expected to yield data which would provide insights relating to the potential of GMI as a useful and effective instructional strategy. Quasi-experimental research methods were followed. The experimental design was a modified "post-test only control group design." Two-hundred-four students in naturally occurring in tact classes formed the experimental and control groups. All groups received instruction in identical science/health content. Two parallel post-tests were administered to all students. Post-test "A" was given immediately after instruction to measure learning acquisition. Post-test "B" was given four weeks later to measure retention of learning. Means for test scores were grouped according to treatment and sub-grouped by the variables: IQ, handedness, identified learning disability, and intellectual giftedness. T_ tests for differences between independent means were conducted. Students' acquisition of basic academic content, when instructed with GMI methodology, was found to differ significantly from students' acquisition of the same content with non-GMI instruction. No statistically significant differences based on instructional methodology were found for content retention. The investigator concluded that GMI instruction may increase learning. Although measures of retention did not show significant differences between groups, a review of the mean scores revealed a minimal difference. This was interpreted to indicate equality of retention between the two methods. Recommendations for further investigation were offered. Post-testing of subjects at additional intervals, and increased training of students and teachers in GMI prior to collection of data were suggested.
273

The Effects of Imaging Ability, Guided Imagery, and Source of Themes on Interview Verbal Behavior

Wixson, Sandra Werre 12 1900 (has links)
Eighty four female undergraduate students participated in a psychotherapy analog study to determine the effects of imagery ability, guided imagery therapy treatments, and personal versus supplied constructs upon self-disclosure variables in a 2 x 3 x 2 Anova design, with repeated measures on the final factor. Dependent variables were measured by reaction time, total talk time, speech duration, silence quotient, and Doster's (1971) Self-Disclosure Rating Scale. Subjects were divided into two imagery ability levels on the basis of local mean scores on Sheehan's (1967) modification of Betts' (1909) Questionnaire upon Mental Imagery. Three treatment procedures were employed: a guided focal imagery treatment, which encouraged imagery involving the interpersonal topics to be discussed, a guided relaxation imagery treatment which used standard sensory relaxation scenes, and a treatment which imparted ambiguous instructions. The final factor was repeated measures of the eight negative topics the subjects were asked to discuss. Four were chosen from the subjects' Role Construct Repertory Test grid (Kelly, 1955; Landfield, 1971), and four were selected from the Semantic Differential (Snider & Osgood, 1969).
274

Administrator Perceptions of the Individually Guided Education Staff Development Process

Reid, George W. 05 1900 (has links)
The problem with which this investigation is concerned is that of analyzing elementary school principals' perceptions of the Individually Guided Education process of staff development. A survey is made of 100 randomly selected principals from 18 states of the United States with regard to the problems of implementing the process in their schools.
275

Signal processing methods for defect detection in multi-wire helical waveguides using ultrasonic guided waves

Yucel, Mehmet Kerim January 2015 (has links)
Non-Destructive Testing of industrial components carries vital importance, both financially and safety-wise. Among all Non-Destructive techniques, Long Range Ultrasonic Testing utilizing the guided wave phenomena is a young technology proven to be commercially valid. Owing to its well-documented analytical models, Ultrasonic Guided Waves has been successfully applied to cylindrical and plate-like structures. Its applications to complex structures such as multi-wire cables are fairly immature, mainly due to the high complexity of wave propagation. Research performed by the author approaches the long range inspection of overhead transmission line cables using ultrasonic guided waves. Existing studies focusing on guided wave application on power cables are extremely limited in inspection range, which dramatically degrades its chances of commercialization. This thesis consists of three main chapters, all of which approaches different problems associated with the inspection of power cables. In the first chapter, a thorough analysis of wave propagation in ACSR (most widely used power cable) cables is conducted. It is shown that high frequency guided waves, by concentrating the energy on the surface layers, can travel much further in the form of fundamental longitudinal wave mode, than previous studies have shown. Defect detection studies proved the system’s capability of detecting defects which introduce either increase or decrease in cross sectional area of the cable. Results of the chapter indicate the detectability of defects as small as 4.5% of the cross sectional area through a 26.5 meter long cable without any post-processing. In the second chapter, several algorithms are proposed to increase the inspection range and signal quality. Well-documented wavelet-denoising algorithm is optimized for power cables and up to 24% signal-to-noise ratio improvement is achieved. By introducing an attenuation correction framework, a theoretical inspection range of 75 meters is presented. A new framework combining dispersion compensation and attenuation correction is proposed and verified, which shows an inspection range of 130 meters and SNR improvement up to 8 dBs. Last chapter addresses the accurate localization of structural defects. Having proven the optimum excitation and related wave propagation in ACSR cables, a system having a more complex wave propagation characteristics is studied. A new algorithm combining pulse compression using Maximal Length Sequences and dispersion compensation is applied to multi-modal signals obtained from a solid aluminum rod. The algorithm proved to be able to improve signal quality and extract an accurate location for defects. Maximal Length Sequences are compared to chirp signals in terms of SNR improvement and localization, which produced favourable results for MLS in terms of localization and for chirp in terms of SNR improvement.
276

Conception d’un dispositif de contrôle non-destructif par ultrasons de structure collée exploitant une cavité réverbérante à retournement temporel / Development of a non-destructive ultrasonic inspection device of a bonded structure using a reverberant cavity with time reversal process

Zabbal, Paul 06 December 2018 (has links)
Le collage suscite un intérêt important pour remplacer les techniques traditionnelles d’assemblage, car il permet d’alléger les structures via une meilleure répartition des contraintes, et également de limiter les contraintes liées à l’assemblage de matériaux différents. Cependant, l’absence de technique de contrôle non destructive robuste de la qualité du collage et plus particulièrement de l’adhésion freine son développement en particulier dans le domaine aéronautique. Dans ce travail une méthode d’inspection ultrasonore d’interfaces collées qui doit révéler des défauts d’adhésion est proposée. Cette technique est validée sur un système représentatif d’applications industrielles, à savoir une liaison entre substrats métalliques liés par un adhésif époxy en film de faible épaisseur. Des défauts ont été introduits au sein de l’interface adhésive (dans l’adhésif ou à l’interface adhésif/substrat) de façon à simuler des défauts rencontrés en environnement industriel. Afin d’améliorer les capacités de détection des méthodes ultrasonores linéaires usuelles, des algorithmes de reconstruction des courbes de dispersion optimisés ont été développés. Cependant, les ondes guidées ne se sont pas montrées suffisamment sensibles à des interfaces faibles dans cette configuration, pour des adhésifs de faible épaisseur et lorsqu’une incertitude des épaisseurs des matériaux est tolérée. Dès lors, des méthodes de contrôle reposant sur l’interaction non-linéaire entre une onde ultrasonore de forte amplitude et un défaut sont proposées car moins système dépendant. Pour détecter et quantifier ces nonlinéarités, des ultrasons suffisamment énergétiques doivent être générés, ce qui implique généralement l’usage de dispositifs électroniques de puissance potentiellement intrinsèquement non-linéaires. Pour contourner ces limitations technologiques, un dispositif dédié est proposé, utilisant des traducteurs alimentés sous tension faible et placés sur un objet réverbérant. L’émission de signaux complexes préalablement établis par étalonnage permet par retournement temporel de concentrer l’énergie acoustique temporellement et spatialement, pour générer des déplacements particulaires ultrasonores de fortes amplitudes à la surface de l’échantillon contrôlé. Pour valider cette approche, le dispositif est utilisé pour contrôler des interfaces collées au sein desquelles différents types de défauts de collage ont été introduits : pollutions (particules de PTFE, démoulant, trace de doigt, etc.), insert. Les échantillons sont finalement testés mécaniquement pour évaluer la sensibilité de la résistance des interfaces à la présence de ces défauts. / Bonding is of great interest to replace traditional assembly techniques, as it makes it possible to lighten structures, through a better distribution of stresses but also to limit the stresses associated with assembling different materials. However, the lack of a robust non-destructive control technique for bonding quality and more particularly adhesion slows down its development, particularly in the aeronautical field. In this work an ultrasonic inspection method of glued interfaces which should reveal defects in adhesion is proposed. This technique is validated on a system representative of industrial applications, metal substrates bonded by a thin film epoxy adhesive. Defects have been introduced into the adhesive interface (in the adhesive or at the adhesive/substrate interface) in order to simulate defects encountered in an industrial environment. In order to improve the detection capabilities of conventional linear ultrasonic guided waves methods, algorithms for reconstructing optimized dispersion curves have been developed. However, the guided waves were not sufficiently sensitive to low interfaces in this configuration, where adhesives are thin, and an uncertainty of material thickness is tolerated. Therefore, control methods based on the non-linear interaction between a high amplitude ultrasonic wave and a defect are proposed. To detect and quantify these non-linearities, sufficiently energetic ultrasound must be generated, which generally involves the use of potentially intrinsically non-linear electronic power devices. To overcome these technological limitations, a dedicated device is proposed, using transducers powered under low voltage and placed on a reverberant object. The emission of complex signals previously established by calibration makes it possible to concentrate acoustic energy temporally and spatially, to generate after time reversal ultrasonic particle movements of high amplitude on the surface of the controlled sample. To validate this approach, the device is used to control glued interfaces in which different types of gluing defects have been introduced: pollution (PTFE particles, release agent, fingerprints, etc.), insert. The samples are finally mechanically tested to assess the sensitivity of the interface resistance to the presence of these defects.
277

Enabling high-throughput sequencing data analysis with MOSAIK

Stromberg, Michael Peter January 2010 (has links)
Thesis advisor: Gabor T. Marth / During the last few years, numerous new sequencing technologies have emerged that require tools that can process large amounts of read data quickly and accurately. Regardless of the downstream methods used, reference-guided aligners are at the heart of all next-generation analysis studies. I have developed a general reference-guided aligner, MOSAIK, to support all current sequencing technologies (Roche 454, Illumina, Applied Biosystems SOLiD, Helicos, and Sanger capillary). The calibrated alignment qualities calculated by MOSAIK allow the user to fine-tune the alignment accuracy for a given study. MOSAIK is a highly configurable and easy-to-use suite of alignment tools that is used in hundreds of labs worldwide. MOSAIK is an integral part of our genetic variant discovery pipeline. From SNP and short-INDEL discovery to structural variation discovery, alignment accuracy is an essential requirement and enables our downstream analyses to provide accurate calls. In this thesis, I present three major studies that were formative during the development of MOSAIK and our analysis pipeline. In addition, I present a novel algorithm that identifies mobile element insertions (non-LTR retrotransposons) in the human genome using split-read alignments in MOSAIK. This algorithm has a low false discovery rate (4.4 %) and enabled our group to be the first to determine the number of mobile elements that differentially occur between any two individuals. / Thesis (PhD) — Boston College, 2010. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.
278

Visitas Teatralizadas em museus: novos meandros para a comunicação museológica / Visits Guided Visits with Theater in museums: new meanders for museological communication

Paes, Gustavo Nascimento 23 August 2016 (has links)
Este trabalho apresenta uma discussão sobre comunicação museológica e de que maneira as instituições trabalham a relação entre museu, público e exposição. Considera-se que a comunicação só se estabelece efetivamente quando sua forma e seu conteúdo mediam, simultaneamente, emoção e informação. Assim, a inserção de \"visitas teatralizadas\" em instituições museológicas pode oferecer o conhecimento não só pela informação em si, mas um conhecimento que, segundo Scheiner (2003), parte da informação transformada pela emoção, podendo então ser vivenciada. Do mesmo modo, o museu precisa dominar outras formas de linguagem, outros sistemas de comunicação que não sejam os habituais. A dissertação estuda e promove a compreensão sobre novas formas de estabelecer um diálogo, neste caso, via \"visitas teatralizadas\". / This paper presents a discussion on museological communication and how the institutions work the relationship among museum, public and exhibition. It is consider that communication is only established effectively when its form and its content mediates simultaneously emotion and information. Thus, the inclusion of \"guided visits with theater\" in museological institutions can provide knowledge not only for the information itself, but knowledge which, according to Scheiner (2003), part of the information transformed by the emotion and can then be experienced. Similarly, the museum must dominate other forms of language, other communication systems that are not usual. The dissertation studies and promotes the understanding of new ways to establish a dialogue, in this case via \"guided visits with theater\".
279

Estudo imaginológico da regeneração óssea guiada associada ou não à terapia de fotobiomodulação (PBMT) em ratas com osteoporose / Imaging study of guided bone regeneration associated or not with photobiomodulation therapy (PBMT) in rats with osteoporosis

Alves, Fernando Amorim Mendonça 14 September 2018 (has links)
A osteoporose é uma doença sistêmica caracterizada pela perda de conteúdo mineral do osso propiciando fraturas críticas. A regeneração óssea guiada e a terapia de fotobiomodulação (PBMT do inglês photobiomodulation therapy) favorecem a regeneração óssea. O objetivo do estudo foi avaliar o efeito da PBMT no reparação óssea guiada de lesões críticas de 36 ratas com osteoporose induzida por ooforectomia. Foram realizadas lesões ósseas estandardizadas nos ossos parietais e então tratadas de acordo com os seguintes grupos experimentais (n=12 lesões por grupo): Controle: sem tratamento adicional; Membrana - Colocação de uma membrana de colágeno suíno comercial (Bio-Gide®) dentro do leito cirúrgico; PBMT1- membrana e aplicação da PBMT1; PBMT2- membrana e aplicação da PBMT2. A PBMT foi realizada com laser de diodo infravermelho no modo contínuo, pontual e em contato (808nm, 40mW, 1,42W/cm2; PBMT1: 3s, 4J/cm2, 0,12J por ponto e PBMT2: 10s, 14J/cm2, 0,4J por ponto) imediatamente, 48 e 96 horas após a cirurgia. Quatro e oito semanas após a cirurgia os animais foram eutanasiados, a calota craniana dissecada, fixada e submetida à análise por microtomografia computadorizada. Foram coletados os seguintes dados: volume ósseo relativo (razão entre o volume ósseo e o volume total), número, espessura e separação de trabéculas, conectividade por densidade e índice de estrutura de modelo (SMI do inglês structure model index). Os dados de cada análise foram comparados pelo teste ANOVA dois critérios/Tukey ou Kruskal Wallis/Dunn e os dados de análises diferentes pelo teste de correlação de Spearman (p<0,05). Diferenças significativas foram observadas em 8 semanas. A PBMT, em especial nos parâmetros de menor energia (0,12J), acelerou o reparo ósseo resultando na obtenção de maior volume ósseo, com grande número de trabéculas, de espessura média, próximas e interconectadas e com valores baixos de SMI. Dentro das limitações deste trabalho in vivo, concluímos que a PBMT acelera a formação e maturação do tecido ósseo neoformado em lesões ósseas críticas de ratas osteoporóticas. / Osteoporosis is a systemic disease characterized by loss of bone mineral content leading to critical fractures. Guided bone regeneration and photobiomodulation therapy (PBMT) favor bone regeneration. The objective of the study was to evaluate the effect of PBMT on the guided bone repair of critical lesions of 36 rats with osteoporosis induced by oophorectomy. Standardized bone lesions were performed on the parietal bones and then treated according to the following experimental groups (n = 12 lesions per group): Control: no additional treatment; Membrane - Placement of a commercial swine collagen membrane (Bio-Gide®) within the surgical bed; PBMT1 membrane and PBMT1 application; PBMT2-membrane and PBMT2 application. PBMT was performed with continuous wave infrared diode lasers in punctual and contact mode (808nm, 40mW, 1.42W / cm2, PBMT1: 3s, 4J / cm2, 0,12J per ponit and PBMT2: 10s, 14J / cm2, 0.4J per point) immediately, 48 and 96 hours after surgery. Four and eight weeks after surgery, the animals were euthanized, the skulls dissected, fixed and submitted to the analysis by computerized microtomography. The following data were collected: bone volume, relative bone volume (ratio of bone volume to total volume), number, thickness and separation of trabeculae, density connectivity and model structure index (SMI). The data from each analysis were compared using the ANOVA two criteria / Tukey or Kruskal Wallis / Dunn test and the different analysis data by the Spearman correlation test (p <0.05). Significant differences were observed at 8 weeks. PBMT, especially in the lower energy parameters (0.12J), accelerated bone repair resulting in higher bone volume, with a large number of trabeculae, medium thickness, close to each other and interconnected, and with low SMI values. Within the limitations of this in vivo study, we concluded that PBMT accelerates the formation and maturation of neoformed bone tissue in critical bone lesions of osteoporotic rats.
280

A novel method to evaluate local control of lung cancer in stereotactic body radiation therapy (SBRT) treatment using 18f-Fdg positron emission tomography (PET)

Unknown Date (has links)
An improved method is introduced for prediction of local tumor control following lung stereotactic body radiation therapy (SBRT) for early stage non-small cell lung cancer (NSCLC) patients using 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET). A normalized background-corrected tumor maximum Standard Uptake Value (SUVcmax) is introduced using the mean uptake of adjacent aorta (SUVref), instead of the maximum uptake of lung tumor (SUVmax). This method minimizes the variations associated with SUVmax and objectively demonstrates a strong correlation between the low SUVcmax (< 2.5-3.0) and local control of post lung SBRT. The false positive rates of both SUVmax and SUVcmax increase with inclusion of early (<6 months) PET scans, therefore such inclusion is not recommended for assessing local tumor control of post lung SBRT. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2013.

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