Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 78-80). Also available in electronic version.

Thesis (M.Ed.)--Regis University, Denver, Colo., 2009. / Title from PDF title page (viewed on Jul. 28, 2010). Includes bibliographical references.

The guided wave technique is an ultrasonic technique which is used to monitor large structures in a variety of industry sectors to safeguard against catastrophic failure. The guided wave technique for pipeline inspection has been commercially used since the early 2000s and this facilitates rapid inspection where from a single location over 100 metres of pipeline can be inspected. This technique is currently being used in pipeline infrastructure across the globe. For the technique to be successful it is highly dependent on a numerous of factors including, frequency selection, array designs and pipeline geometries. The transducers used on pipeline are dry coupled and the magnitude of the signal transmitted is dependent on the normal force applied to it. If this force is not controlled the signal being transmitted can degrade and lead to the difficult analysis of a complex signal. In this thesis studies have been undertaken to understand the relationship between dry force coupling of the transducer and the signal received, aligning this connection to classical contact theory. This is then further to extended to the influence surface contact conditions have on the transmission of signal from the transducer. Analysis of the results detected a peak in the operational frequency response which in turn initiated electrical impedance and structural resonance measurements to identify the presence of resonances which are induced by dry coupling. This behaviour was then modelled in FEA software and the validity of the FEA approach was tested against several prototype transducers. This thesis has been funded in joint collaboration between the Engineering Physics and Science Research Council and TWI ltd.

Guided imagery, a therapeutic technique in which a healer directs an individual to visualize a scene or sensations, has existed for millennia and is often used within healthcare settings today. A small, though growing number of studies among clinical samples demonstrate that guided imagery produces positive effects such as decreased pain and anxiety. Few studies have dismantled this intervention in order to isolate its active ingredients, and even fewer studies have determined for whom this intervention works. The current study sought to address these gaps in the literature by examining the effects of guided imagery on mood and anxiety among a college sample. The effects of a single session of non-directive guided imagery were examined through a repeated measures, pre-test post-test design with three experimental conditions. Multivariate analysis of data from 107 adults showed that following a distress induction, guided imagery significantly decreased anxiety and negative affect. However, guided imagery did not produce significantly greater changes in mood and anxiety than quiet rest or attention control conditions as hypothesized. Individual difference variables hypothesized as moderators (trait absorption, imagery vividness, imagery control) did not predict outcome; however, self-reported engagement in the experimental conditions predicted magnitude of change in outcome. The discussion outlines potential reasons for these unique findings as well as clinical implications and future directions for research.

nÃo hà / O objetivo desse estudo foi avaliar membranas de colÃgeno polianiÃnico (CPA) reticuladas e impregnadas com hidroxiapatita, manufaturadas pelo Departamento de FÃsica da Universidade Federal do CearÃ. Dividiu-se o trabalho em 2 etapas, onde inicialmente avaliou-se a biocompatibilidade e a biodegradaÃÃo de 6 diferentes membranas de CPA, divididas nos seguintes grupos: trÃs com 0, 25 e 75 ciclos de impregnaÃÃo com hidroxiapatita (CPA, CPA 25, CPA 75) e mais trÃs cujas membranas foram reticuladas com glutaraldeÃdo (GA) (CPA GA, CPA 25GA, CPA 75GA) inseridas em tecido subcutÃneo de ratos. AnÃlises histopatolÃgicas do infiltrado inflamatÃrio, atividade de mieloperoxidase (MPO), dosagem de citocinas, espessura de cÃpsula fibrosa, imunohistoquÃmica para metaloproteinase e biodegradaÃÃo das membranas foram avaliadas apÃs 1, 7, 15, 30, 60 e 120 dias. Posteriormente, avaliou-se o efeito das 3 melhores membranas na regeneraÃÃo Ãssea guiada usando defeito Ãsseo crÃtico em calvÃria de ratos (DOC), onde as membranas foram posicionadas sobre o defeito. FormaÃÃo Ãssea foi avaliada com base na radiografia digital (RD), tomografia computadorizada (TC) e anÃlise histolÃgica, 24 horas, 4, 8 e 12 semanas apÃs o procedimento cirÃrgico. MPO e dosagem de citocinas foram realizadas apÃs 24 horas. No subcutÃneo, as membranas reticuladas com GA mostraram espessa cÃpsula fibrosa e menor reaÃÃo inflamatÃria permanecendo intactas apÃs 120 dias. No modelo de regeneraÃÃo Ãssea em calvÃria de ratos, apÃs 12 semanas, os grupos CPA GA e CPA 25GA apresentaram reduÃÃo significativa da Ãrea radiolÃcida quando comparadas ao grupo basal. A anÃlise histolÃgica mostrou que nos grupos CPA GA e CPA 25GA as membranas ainda estavam intactas, envolvidas por uma espessa cÃpsula fibrosa e as membranas do grupo CPA 75GA apresentaram inÃcio de reabsorÃÃo. NÃo foi encontrada diferenÃa estatÃstica entre os grupos quanto a atividade MPO e citocina IL-1β. ConcluÃmos que as membranas reticuladas mostraram-se mais biocompatÃveis e se mantiveram livre de biodegradaÃÃo no perÃodo de observaÃÃo. Essas membranas induziram o fechamento dos defeitos Ãsseos e nÃo induziram reaÃÃo inflamatÃria. A impregnaÃÃo de hidroxiapatita nÃo acelerou a cicatrizaÃÃo do defeito cirÃrgico. Nossos resultados sugerem que as membranas de CPA reticuladas poderÃo ser Ãteis nos processos em que a formaÃÃo de um novo osso depende de uma duraÃÃo mais prolongada da barreira mecÃnica. / The aim of this study was to evaluate polyanionic collagen (PAC) membranes reticulated and impregnated with hydroxyapatite, manufactured by the Physics Department, Federal University of CearÃ. This study was divided into two stages, initially it was evaluated the biocompatibility and biodegradation of six different membranes of PAC, divided into the following groups: three with 0, 25 and 75 cycles of impregnation with apatite (PAC, PAC 25, PAC 75 ) and three more whose membranes were crosslinked with glutaraldehyde (GA) (GA PAC, PAC 25GA, PAC 75GA) inserted into the subcutaneous tissue of rats. Histopathological analyzes of inflammatory infiltration, myeloperoxidase activity (MPO), cytokine, thickness of fibrous capsule, immunohistochemistry for metalloproteinase and degradation of the membranes were evaluated after 1, 7, 15, 30, 60 and 120 days. Subsequently, it was evaluated the effect of the three best membranes in guided bone regeneration using bone critical defects in rat calvaria (DOC), where the membranes were placed over the defect. Bone formation was evaluated based on digital radiography (DR), computed tomography (CT) and histological analysis, 24 hours, 4, 8 and 12 weeks after surgery. MPO and cytokine were performed after 24 hours. In the subcutaneous tissue, the membranes crosslinked with GA showed thick fibrous capsule, less inflammatory reaction and remained intact after 120 days. In the bone regeneration model in rat calvaria, after 12 weeks, PAC GA and PAC 25GA groups showed significant reduction in radiolucent area compared to the baseline group. Histological analysis showed that in PAC GA and PAC 25GA groups, membranes were still intact, surrounded by a thick fibrous capsule and in PAC 75GA group, membranes showed early resorption. There was no statistical difference between groups in MPO activity and IL-1β. We conclude that the crosslinked membranes were more biocompatible and remained free from degradation during the observation period. These membranes induced closure of bone defects and did not induce inflammatory reaction. The impregnation of hydroxyapatite did not accelerate the healing of surgical defect. Our results suggest that the crosslinked membranes CPA may be useful in cases where new bone formation is dependent on a longer duration of mechanical barrier.

M.Sc. (Mathematical Statistics) / This dissertation deals with the computation of nonlinear control strategies for an autonomous vehicle. The vehicle consists of two wheels attached to an axle. It is assumed that both wheels roll without slipping leading to nonholonomic constraints. A third order nonlinear kinematic model of the vehicle is derived from these constraints. It is further assumed that the vehicle has builtin feedback controllers independently regulating the rotational velocities of the wheels (using electric motors as actuators). Thus, the vehicle is maneuvered by applying a separate rotational velocity reference command to the feedback controller of each wheel. The closed loop system dynamics from the reference command to the wheel rotational velocity is approximately modelled by a first order system. This leads to a fifth order nonlinear state-space model for the vehicle. The above-mentioned reference commands constitute the control input variables of the vehicle model and are subject to amplitude constraints. Firstly, a methodology is developed for computing reference command strategies to drive the autonomous vehicle from a specified initial state to a desired final state in a given time and such that a circular obstacle is avoided. The vehicle performs the required maneuver whilst satisfying all the specifications and constraints. Secondly, feedback reference command laws are developed such that a specified point just ahead of the vehicle asymptotically tracks a given reference trajectory in the horizontal plane. The feedback control law steers the vehicle onto the reference path from any initial position and keeps it moving on the path. Thirdly, the stochastic system performance is evaluated when the above-mentioned tracking control strategy is applied and the initial state of the vehicle is a random vector.

The main aim of the study is to document the development of US Fleet Ballistic Missile technology from its mid-1950s beginnings through to Trident II D5. This historical documentation is framed by a perspective which seeks to understand how technology evolves and what the relationship is between, to put it simply, technology and strategy, or technology and politics. Of particular interest in this case study is the relationship between technology and nuclear strategy. It is a commonplace assertion that technology is a dominant, determining factor in the arms race, that indeed there is a technological imperative. In particular there are many who argue that improvements in missile accuracies have driven changes in nuclear strategy away from counter-city retaliatory deterrence to war-fighting counter-force postures. Tracing the history of FBM development from Polaris, considered by many the archetypal counter-city deterrent, to Trident II, with hard-target kill capability comparable to MX, helps our understanding of this issue. In considering this central theme, the development of FBM technology is analysed in the social constructionist terms of the 'new' sociology of technology. This approach argues that technical change must be explained impartially and symmetrically, and that the success of a particular technology is not sufficient explanation in itself, but is rather exactly what needs to be explained. Technology is considered to be underdetermined by the physical world, and thus to be fundamentally shaped by the social world. The extreme characterizations of the relationship between technology and politics - either that technology is simply the tool of political will or that technology is out-of-control (as in the view that accuracy improvements have driven strategy) - are found to be inadequate in this study. Instead it is found that the 'bureaucratic politics' approach captures much of the rich complexity of the process of technological change. Yet even this approach fails fully to capture the complex inter-relatedness of 'technology' and 'politics', nor does it take into account the importance of the physical production of technology.

Abstract Interactive image-guided neurosurgery for the resection of brain tumors was developed within the last 10 years at different neurosurgical centers around the world to improve the safety of the surgery and the functional outcome of the patients. Since 1987, the Oulu Neuronavigator System, consisting mainly of a mechanical arm, visualization software, an ultrasound transducer and a computer, was developed at the Neurosurgical Research Unit, University of Oulu, Finland. It was the first system to incorporate the principle of the common surgical axis for visualization, including intraoperative ultrasonography. A precommercial version of the device was jointly developed with Elekta Ab, Stockholm, Sweden, as a public project under EUREKA and introduced into a clinical beta-phase trial in 1994 as the Leksell Index System™. A total of 19 operations were performed at the Oulu University Hospital between September 1994 and September 1996 for patients harboring different kinds of intracranial tumors, especially cerebral gliomas. This thesis gives a comprehensive review of the literature from the roots of stereotaxy to the latest developments in interactive image-guided neurosurgery and discusses the advantages and disadvantages of the Leksell Index System™ with special reference to the clinical series that was performed at our institution. Future therapy strategies for the treatment of patients with cerebral gliomas, especially glioblastoma multiforme are envisioned, focusing on the further improvement of surgical interventions. The clinical trial proved that the employed neuronavigator system is versatile and safe and that there are no adverse effects, complications or surgical mortality due to the device. It enabled the surgeon to plan smaller sized and better centered skin incisions and craniotomies and to approach the target lesion with less dissection of intact brain tissue. Despite more radical removal of lesions the overall invasiveness of the operation was decreased in 63.2% of the cases, the duration of the procedure was decreased in 78.9%, and the surgeon's feeling of safety could be improved in 89.5% of the operations. Due to the use of intraoperative imaging (with ultrasound) the experience provides a unique basis for next generation neuronavigators and also for interventional MRI.

Abstract The purposes of the present research were to evaluate (1) the value of ultrasonographically guided fine-needle aspiration biopsy (US-FNAB) in nonpalpable suspicious breast lesions, (2) the preoperative use of methylene blue staining in nonpalpable galactographically suspicious breast lesions, (3) the determinants of positive histologic margins and residual cancer in wire-guided biopsy (WGB) of nonpalpable breast cancer and in lumpectomy for early breast cancer and the determinants of positive radiologic margins and the correlation between radiologic and histologic margins and residual disease in WGB of nonpalpable breast cancer, (4) the assessment of lumpectomy margins by touch preparation cytology in early breast cancer, and (5) the cosmetic outcome of WGB performed for benign breast lesions. The sensitivity and specificity of US-FNAB in 90 nonpalpable breast lesions were 84% and 93%, respectively. Preoperative methylene blue staining was successful in 22 out of 30 (73%) cases, making subsequent selective minimal volume microdochectomy easy to perform. Multivariate analysis of 21 prospectively evaluated variables was done after 71 WGBs of nonpalpable breast cancer followed by 54 re-excisions. Large mammographic lesions had more often positive radiologic margins. Multifocality, large pathologic size and superficial excision were related to positive histologic margins and multifocality to residual disease in re-excisions. The sensitivity and specificity of specimen radiography for predicting histologic margins were 38% and 81% and those for residual disease 27% and 79%, respectively. The corresponding figures for histologic margins in predicting residual disease were 85% and 59%, respectively. In a prospective series of 55 consecutive lumpectomies for early breast cancer, positive histologic margins were found more often in the presence of intraductal cancer and if the pathologic size of the index tumor was large. Residual disease was found in 38% of the cases with positive and in 15% of the cases with negative histologic margins. A multifocal and nonpalpable index tumor predicted residual cancer in 34 re-excision specimens. The sensitivity and specificity of touch preparation cytology in predicting histologic margins were 38% and 85%, respectively. In WGB, the overall cosmesis 6 months after surgery was satisfactory in 75 % of the 101 prospectively evaluated patients with benign proven lesions. Cosmesis was poorer after deep excisions and complications. The results indicate that US-FNAB is a useful tool in evaluating nonpalpable suspicious breast lesions. Preoperative methylene blue staining crucially facilitates selective minimal volume microdochectomy in three-quarters of cases. To obtain free margins in WGB, mammographically and pathologically large lesions should be removed with wider excisions extending down to the fascia. However, radiologic margins in WGB and histologic margins both in WGB and in lumpectomy for early breast cancer may be misleading. Re-excision of the biopsy site of multifocal tumors after WGB and lumpectomy should be considered. This is also important after superficial excision in WGB due to the considerable risk of residual disease. Touch preparation cytology cannot be recommended for the assessment of margins in lumpectomy specimens of early breast cancer. Cosmetic outcome after WGB of benign breast lesions is satisfactory in 75 % of cases. Deep excisions and complications endanger the cosmetic outcome. Preoperative biopsy and tumor localization methods have proven their utility; nevertheless, free margins are still difficult to obtain and to evaluate accurately. The surgeon may often be forced to choose between free margins and an acceptable cosmetic outcome.

Modern cell phone hardware, due to its integrated peripherals, provides a low cost intelligent controller for use in the navigation of an Automated Guided Vehicle (AGV). Most commercial AGV’s use proprietary hardware which is expensive to replace and also difficult to maintain. Using industrial hardware components combined with Android mobile platforms could provide a low-cost alternative. This would be easier to maintain, using existing in-house factory maintenance knowledge. A prototype AGV was designed and developed based on an integrated system between an industrial Programmable Logic Controller (PLC) and an Android operating system mobile platform. This system utilises the mobile platforms integrated Global Position System (GPS) or video camera as tools for navigation. Experimental tests were performed to determine whether the prototype can navigate a predefined course by making use of GPS and camera line following algorithms. The accuracy of the line following algorithm was influenced by the speed at which the research AGV moved. Mounting the Android camera higher above the ground improved the vision and therefore accuracy of the algorithm. The GPS algorithm successfully navigated to various waypoints. The accuracy of the implemented GPS unit on the Android device is its limitation. The research unit was only capable of reaching a waypoint consistently within a three-metre radius.