Dissertations / Theses on the topic 'Manipulation of ground'

Les dernières années ont vu le développement de recherches portant sur l'interaction physique entre les robots aériens et leur environnement, accompagné de l'apparition de nombreux nouveaux systèmes mécaniques et approches de régulation. La communauté centrée autour de la robotique aérienne observe actuellement un déplacement de paradigmes des approches classiques de guidage, de navigation et de régulation vers des tâches moins triviales, telle le développement de l'interaction physique entre robots aériens et leur environnement. Ceci correspond à une extension des tâches dites de manipulation, du sol vers les airs. Cette thèse contribue au domaine de la manipulation aérienne en proposant un nouveau concept appelé MAGMaS, pour " Multiple Aerial Ground Manipulator System ". Les motivations qui ont conduites à l'association de manipulateurs terrestres et aériens pour effectuer des tâches de manipulation coopérative, résident dans une volonté d'exploiter leurs particularités respectives. Les manipulateurs terrestres apportant leur importante force et les manipulateurs aériens apportant leur vaste espace de travail. La première contribution de cette thèse présente une modélisation rigoureuse des MAGMaS. Les propriétés du système ainsi que ses possibles extensions sont discutées. Les méthodes de planning, d'estimation et de régulation nécessaire à l'exploitation des MAGMaS pour des tâches de manipulation collaborative sont dérivées. Ce travail propose d'exploiter les redondances des MAGMaS grâce à un algorithme optimal d'allocation de forces entre les manipulateurs. De plus, une méthode générale d'estimation de forces pour robots aériens est introduite. Toutes les techniques et les algorithmes présentés dans cette thèse sont intégrés dans une architecture globale, utilisée à la fois pour la simulation et la validation expérimentale. Cette architecture est en outre augmentée par l'addition d'une structure de télé-présence, afin de permettre l'opération à distances des MAGMaS. L'architecture générale est validée par une démonstration de levage de barre, qui est une application représentative des potentiels usages des MAGMaS. Une autre contribution relative au développement des MAGMaS consiste en une étude exploratoire de la flexibilité dans les objets manipulés par un MAGMaS. Un modèle du phénomène vibratoire est dérivé afin de mettre en exergue ses propriétés en termes de contrôle. La dernière contribution de cette thèse consiste en une étude exploratoire sur l'usage des actionneurs à raideur variable dans les robots aériens, dotant ces systèmes d'une compliance mécanique intrinsèque et de capacité de stockage d'énergie. Les fondements théoriques sont associés à la synthèse d'un contrôleur non-linéaire. L'approche proposée est validée par le biais d'expériences reposant sur l'intégration d'un actionneur à raideur variable léger sur un robot aérien
In recent years, the subject of physical interaction for aerial robots has been a popular research area with many new mechanical designs and control approaches being proposed. The aerial robotics community is currently observing a paradigm shift from classic guidance, navigation, and control tasks towards more unusual tasks, for example requesting aerial robots to physically interact with the environment, thus extending the manipulation task from the ground into the air. This thesis contributes to the field of aerial manipulation by proposing a novel concept known has Multiple Aerial-Ground Manipulator System or MAGMaS, including what appears to be the first experimental demonstration of a MAGMaS and opening a new route of research. The motivation behind associating ground and aerial robots for cooperative manipulation is to leverage their respective particularities, ground robots bring strength while aerial robots widen the workspace of the system. The first contribution of this work introduces a meticulous system model for MAGMaS. The system model's properties and potential extensions are discussed in this work. The planning, estimation and control methods which are necessary to exploit MAGMaS in a cooperative manipulation tasks are derived. This works proposes an optimal control allocation scheme to exploit the MAGMaS redundancies and a general model-based force estimation method is presented. All of the proposed techniques reported in this thesis are integrated in a global architecture used for simulations and experimental validation. This architecture is extended by the addition of a tele-presence framework to allow remote operations of MAGMaS. The global architecture is validated by robust demonstrations of bar lifting, an application that gives an outlook of the prospective use of the proposed concept of MAGMaS. Another contribution in the development of MAGMaS consists of an exploratory study on the flexibility of manipulated loads. A vibration model is derived and exploited to showcase vibration properties in terms of control. The last contribution of this thesis consists of an exploratory study on the use of elastic joints in aerial robots, endowing these systems with mechanical compliance and energy storage capabilities. Theoretical groundings are associated with a nonlinear controller synthesis. The proposed approach is validated by experimental work which relies on the integration of a lightweight variable stiffness actuator on an aerial robot

Introduction Many chiropractic articles and textbooks discuss gait, but there actually has been little research into the effects of chiropractic adjustment on gait. This pilot study used a quantitative method of gait evaluation before and after a series of chiropractic visits. Hypotheses: (1) adults with chronic low back pain (CLBP) would show increased variability in vertical ground reaction forces (VGRF) while walking, as compared to healthy control subjects, and (2) that, following chiropractic care, will show decreased variability. Methods VGRF data were collected for 6 controls and compared to 9 CLBP participants, who were also evaluated before and after the first visit of care and over 7 visits. Data were analyzed by Mean Standard Deviation (MSD), Mean Coefficient of Variation (MCV), and the Coefficient of Variation of loading rate. Chiropractic care consisted of “high velocity low amplitude” thrust type procedures, flexion-distraction, pelvic wedges, light mobilization, and stretching. Results CLBP participants had somewhat greater variability and became slightly less variable post-care; differences were not significant. Limitations: Some participants had no impairment of walking at baseline; MSD is an uncommon measure, and more research is needed; these results (small group seen by a single doctor) may not be generalizable. Conclusions Participants with CLBP had slightly more variability and had slight decreases in variability following chiropractic care. Differences were not statistically significant. With this small pilot study as a guide, more research should be done with larger groups and improved participant selection.

Environmental restoration is emerging as a major driver in the repair and reversal of some of the world’s most severely degraded landscape systems, with growing interest in the status and composition of restoration efforts. Although much has already been written about the theory and practice of environmental restoration, both positive and negative, hitherto the literature has tended to overlook the complexity bound up in defining restoration discourses, and perhaps more importantly, the physical, material consequences instilled through such human choice. The mutability of discourses of environmental restoration means that it can be moulded and (re-)shaped by different actors and contexts, with different values and meanings attached to ‘nature’. There exist multiple and contested natures of environmental restoration - nature(s) both in the sense o f the properties of restoration, and also that which is restored to a site. In this doctoral thesis, I demonstrate how discourses of environmental restoration are defined and interpreted, which discourses (if any) appear to dominate, and how these are mobilised to produce ‘restored nature’. Attention is also awarded to the environmental implications incurred when such discourses are played out on the ground. The research is grounded empirically through reference to the case studies o f the Eden Project (Cornwall, UK), the National Forest Company (Derbyshire, UK), and the Walden Woods Project (Lincoln, MA) and their adoption of restoration practices. Analysing the processes and practices of environmental restoration within a framework of social nature and cultural landscapes serves to destabilise the dualism distancing nature from society - a preserve of environmental ethics and philosophy - for such synergy not only highlights how ideas of (restored) nature are socially constructed, but also addresses the material production of nature, reinforcing the interactions between natural and societal actors.

Although much effort has been placed into the reduction of risks associated with manual materials handling, risk of musculoskeletal disorder development remains high. This may be due to the additional muscle activity necessary for the maintenance of postural equilibrium during work tasks. This research proposes that postural control and subsequent additional muscle activity is influenced by the magnitude of the external load and the degree of body movement. The objective of this research was to identify whether performing tasks with increased external load and with a greater degree of trunk motion places additional strain on the musculoskeletal system in excess of that imposed by task demands. Twenty-four male and twenty-four female subjects performed four load manipulation tasks under three loading conditions (0.8kg, 1.6kg, and 4kg). Each task comprised of a static and dynamic condition. For the static condition, subjects maintained a stipulated posture for ten seconds. The dynamic condition required subjects to move and replace a box once every three seconds, such that a complete lift and lower cycle was performed in six seconds. Throughout task completion, muscle activity of six pairs of trunk muscles were analysed using surface electromyography. This was accompanied by data regarding ground reaction forces obtained through the use of a force platform. After the completion of each condition subjects were required to identify and rate body discomfort. Differential analysis was used to isolate the muscle activity and ground reaction forces attributed to increased external load and increased trunk movement. It was found that the heaviest loading conditions (4kg) resulted in significantly greater (p<0.05) muscle activation in the majority of muscles during all tasks investigated. The trend of muscle activity attributed to load was similar in all significantly altered muscles and activation was greatest in the heaviest loading condition. A degree of movement efficiency occurred in some muscles when manipulating loads of 0.8kg and 1.6kg. At greater loads, this did not occur suggesting that heavier loading conditions result in additional strain on the body in excess of that imposed by task demands. In manipulated data, trend of vertical ground reaction forces increased with increased load in all tasks. Sagittal movement of the centre of pressure attributed to load was significantly affected in manipulated data in the second movement phase of the “hip shoulder” task and the second movement phase of the “hip twist” task. The “hip reach” task was most affected by increased load magnitude as muscle activity attributed to load was significantly different (p<0.05) under increased loading conditions in both movement phases in all muscles. Further, a significant interactional effect (p<0.05) between condition and data point was found in all muscles with the exception of the right and left lumbar erector spinae during the second movement phase of the “hip reach” task. Muscle activity associated with increased trunk motion resulted in additional strain on the trunk muscles in the “hip shoulder” and “hip reach” tasks as muscle activity associated with the static component of each of the above tasks was greater than that of the dynamic tasks. Trend of ground reaction forces attributed to increased trunk motion generally increased under increased loading conditions. Additionally, a significant interactional effect (p<0.05) between load and muscle activity pattern was found in all muscles during all tasks, with the exception of the right rectus abdominis in the first movement phase of the “hip shoulder’ task, the left rectus abdominis in the second movement phase of the “hip knee” task and the right latissimus dorsi during the first movement phase of the “hip twist” task. This was accompanied by a significant interactional effect (p<0.05) between load and sagittal centre of pressure movement attributed to load, in both movement phases of all tasks investigated. From this research it can be proposed that guidelines may underestimate risk and subsequently under predict the strain in tasks performed with greater external loads as well as tasks which require a greater degree of trunk motion. Therefore, this study illustrates the importance of the consideration of the muscle activity necessary to maintain postural equilibrium in overall load analyses.

The main contribution of this project to the field of cold and ultracold molecules is we firstly demonstrated successful manipulation of the motion of polyatomic molecular beam in the rotational ground state, which has the lowest temperature of all possible states. Chapter 1 gives a summary of this field, including the application of cold and ultracold molecules, the methods to obtain them, and each method’s advantages and disadvantages. Once we decelerate molecular ensembles, we would like to trap the cold and ultracold molecules in electric trap, megnetic trap and megneto-optical trap. Chapter 2 starts with an introduction of the concept of supersonic beam and the basic knowledge of it, such as the specific features. The experimental setup will also be presented and explained in this chapter. The main highlight of this project is that we are manipulating molecules in the real ground state. Our molecular source is a Counter Rotating Nozzle(CRN), which can precool (or slow in alternate terminology) molecules in all states including the rotational ground state. The principle and performance of CRN will be presented and explained in Chapter 3. After obtaining a well precooled molecular beam, the microwave lens effect on various species is presented in Chapter 4. Meanwhile, the principle of AC Stark shift, AC dipole force and the microwave standing wave modes, such as TE modes and TM modes, will be explained in this chapter as well. Finally, I’ll summarize, draw conclusion of this work and describe the future expectation of this project in Chapter 5.

This thesis extends the recently reported ground state sideband cooling of the axial motion of a single ion to a broader frequency range of the axial motion, the radial motion and ion crystals. Once cold, coherent control of these different configurations is demonstrated. The experimental work in this thesis uses 40Ca+ ions that can be coherently addressed on a narrow linewidth optical transition at 729 nm. The technique of axialization that resonantly couples the two radial modes of motion is used to enhance laser Doppler cooling leading to mean phonon occupation numbers in the low hundreds for both modes. The sideband cooling technique is then used to simultaneously cool both the motional modes to within one phonon of the ground state for the first time evers. Sideband cooling is then also employed to cool the axial modes of many ion Coulomb crystals in two different configurations. For two ions in a 1D chain, motional occupation numbers of nbar_COM=0.30(4) and nbar_B=0.07(3) are achieved. For two ions in a planar 2D configuration the result for the two modes are nbar_T=nbar_COM < 0.1. This technique is scaled up to demonstrate ground state occupation of up to 10 ions in the planar configuration. The axial mode of motion of a single motion is used to characterise the coherent addressing capabilities in our system through optical and motional Ramsey spectroscopy. We observe optical coherence times of 1.78(4) ms and motional coherence times of 590(12) ms. Dynamical decoupling techniques are shown to extend these coherence times. Furthermore, basic decoherence models are validated in high-lying non-thermal motional states that are prepared by a sideband heating technique. Progress towards entangling gates is demonstrated using a bichromatic laser beam to prepare non-classical states of motion.

This thesis explores how cognitive artefacts contribute to the process of reaching common ground within collaborative groups through a study of both Clark's theory of Common Ground and of how artefacts are understood to be used, both by individuals and as seen in distributed cognition. This was accompanied by an ethno-methodologically inspired study in the natural setting of a kitchen to observe how artefacts are used when negotiationg common ground. After the study's completion, participants were interviewed in order to establish whether common ground was successfully established ant to look for consistency between obeservations from the study and how the participants motivate their actions. The study was analysed in order to find patterns, of which four distinct kinds were indentified; these categories were then related to facts established in the study of Common Ground and artefacts.

Thesis (MSc)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: An ultra-fast laser pulse can be described in the time or frequency domain. If the timebandwidth product of an ultra-fast pulse is not satisfied, then the pulse is stretched. Stretching can be described in the time or frequency domain. In the time domain, it is called a chirp and in the frequency domain, it is known as the group delay dispersion GDD. Various techniques can be used to stretch and compress laser pulses. In this project, a prism pulse compressor used for compressing stretched pulses was built. A 200nm supercontinnum generated in an all normal dispersion photonic crystal fibre (ANDi-PCF) was compressed using the prism pulse compressor from 2ps to 140fs. The experiment and physical interpretation presented in this project suggest that a shorter pulse duration less than the measured 140fs of the compressed supercontinnum can be obtained.
AFRIKAANSE OPSOMMING: 'n Ultra-vinnige laser puls kan beskryf word in tyd of frekwensie. As die tyd-bandwydte produk van ‘n ultra-vinnige puls nie bevredig is nie, dan is die puls uitgerek. Hierdie uitrekking kan beskryf word in tyd of frekwensie. In tyd word dit tjirp genoem en in frekwensie groep vertraging dispersie. Verskeie tegnieke kan gebruik word om ‘n laser puls te rek of saam te pers. In hierdie projek is ‘n prisma puls kompressor gebou om uitgerekte pulse saam te pers. ‘n 200nm bre e bandwydte puls (“supercontinuum”) is gegenereer in ‘n fotoniese kristal optiese vesel wat uitsluitlik normale dispersie toon (ANDI-PCF) en die puls is toe saamgepers met behulp van die prisma puls kompressor van‘n oorspronklike 2ps na 140fs. Die eksperiment en fisiese interpretasie wat in hierdie projek aangebied word dui daarop dat ‘n nog korter puls, minder as die gemete 140 fs, verkry kan word deur die bre e bandwydte puls verder saam te pers.

Declining greater sage-grouse populations (Centrocercus urophasianus; hereafter sage-grouse) have led to increased concern regarding the long-term stability of the species. Previous research has identified factors contributing to the observed population declines. Habitat degradation and loss have been implicated as major factors in population declines. Although much is known about sage-grouse biology, more information is needed about population responses to specific management actions. This research was conducted to document sage-grouse responses to site-specific management actions. Additionally, I evaluated sage-grouse temporal and seasonal habitat-use and the comparability of techniques used by range and wildlife managers to measure vegetation responses of habitat management. Specifically, I evaluated 1) whether chemical analysis (gas chromatography) of sage-grouse fecal pellets could identify sagebrush species in sage-grouse winter diets, 2) the comparability of the line-point intercept and Daubenmire canopy cover methods for estimating canopy cover, 3) the response of sage-grouse broods to prescribed burns in a high elevation sagebrush community in northeastern Utah, and 4) the vegetation and insect characteristics of sites used by sage-grouse broods during a 24-hour period. I was able to determine wintering sage-grouse diets using gas chromatography by analyzing fecal pellets. This research also confirmed that black sagebrush (Artemisia nova) was an important component of sage-grouse winter diets in western Box Elder County and Parker Mountain populations. The line-point intercept and Daubenmire methods for estimating canopy cover are not comparable. Sage-grouse broods selected small (~ 25 ha) patchy prescribed burns in high elevation mountain big sagebrush (A. tridentata vaseyana) communities in northeastern Utah. Sage-grouse brood-site use in northwestern Utah did not differ during the diurnal hours, but nocturnal roost sites were characterized by shorter statured shrubs and more bare ground when compared to midday sites.

This dissertation details three studies dealing with the manipulation of nucleicacids. In the first investigation, each of the four natural nucleobases were analyzed for theability to serve as a universal template at the ligation junction of a T4 DNA ligasereaction. This resulted in the first instance of sequence-independent ligation catalyzed byany DNA ligase. Although all of the nucleobases display universal templatingcapabilities, thymidine and guanosine provided the most effective results. In addition,lowered MgCl2 and ATP concentrations, as well as the inclusion of DMSO, also aided inthe sequence-independent ligation reported here. In the course of these studies, currentmethods of removing urea from denaturing-gel purified nucleic acids provedcumbersome. Therefore, in the second study simple butanol extraction was examined as ameans to eliminate urea from nucleic acid solutions. Stepwise butanol extraction was themost effective approach to solving this problem and provided a much needed techniquefor nucleic acid purification. This type of extraction also does not result in significantlosses of nucleic acid sample. The third study exploits the molecular recognition andcatalytic properties inherent in an autocatalytic group I intron to develop a ribozyme thatcan replace the 5' end of an RNA substrate with a different RNA. This 5' replacementsplicing reaction can potentially repair mutations on the 5' ends of RNA transcripts thatlead to a variety of genetic mutations. The model system was a common mutation in asmall model mimic of the k-ras gene in vitro, which predisposes individuals to lungcancer. This 5' replacement splicing reaction occurred in vitro using this small modelsystem; the reaction was also enhanced by the alteration of the molecular interactionsinvolved. The results and implications of each of these studies are detailed in thisdissertation.

The kinematic mapping of a rigid open-link manipulator is a homomorphism between Lie groups. The homomorphisrn has solution groups that act on an inverse kinematic solution element. A canonical representation of solution group operators that act on a solution element of three and seven degree-of-freedom (do!) dextrous manipulators is determined by geometric analysis. Seven canonical solution groups are determined for the seven do! Robotics Research K-1207 and Hollerbach arms. The solution element of a dextrous manipulator is a collection of trivial fibre bundles with solution fibres homotopic to the Torus. If fibre solutions are parameterised by a scalar, a direct inverse funct.ion that maps the scalar and Cartesian base space coordinates to solution element fibre coordinates may be defined. A direct inverse pararneterisation of a solution element may be approximated by a local linear map generated by an inverse augmented Jacobian correction of a linear interpolation. The action of canonical solution group operators on a local linear approximation of the solution element of inverse kinematics of dextrous manipulators generates cyclical solutions. The solution representation is proposed as a model of inverse kinematic transformations in primate nervous systems. Simultaneous calibration of a composition of stereo-camera and manipulator kinematic models is under-determined by equi-output parameter groups in the composition of stereo-camera and Denavit Hartenberg (DH) rnodels. An error measure for simultaneous calibration of a composition of models is derived and parameter subsets with no equi-output groups are determined by numerical experiments to simultaneously calibrate the composition of homogeneous or pan-tilt stereo-camera with DH models. For acceleration of exact Newton second-order re-calibration of DH parameters after a sequential calibration of stereo-camera and DH parameters, an optimal numerical evaluation of DH matrix first order and second order error derivatives with respect to a re-calibration error function is derived, implemented and tested. A distributed object environment for point and click image-based tele-command of manipulators and stereo-cameras is specified and implemented that supports rapid prototyping of numerical experiments in distributed system control. The environment is validated by a hierarchical k-fold cross validated calibration to Cartesian space of a radial basis function regression correction of an affine stereo model. Basic design and performance requirements are defined for scalable virtual micro-kernels that broker inter-Java-virtual-machine remote method invocations between components of secure manageable fault-tolerant open distributed agile Total Quality Managed ISO 9000+ conformant Just in Time manufacturing systems.

This research investigates accounting practices in four Tanzanian Local Government Authorities (LGAs). It seeks to understand how accounting is practiced and the situations which sustain its undertaking. The peculiar role of local governments in the delivery of public services and the influence of accounting on the same has motivated this study (Lapsley & Mussari, 2008). It has also been driven by the inadequacy of interpretive theoretically based informed studies into public sector entities, and the limited accounting research in the emerging economies (Goddard, 2010). The study applies an interpretive approach to investigate accounting in the organisations in which it operates (Ahrens & Mollona, 2007), and executes a grounded theory method to develop a theory systematically from the raw data (Glaser & Strauss, 1967). In order to ensure the general application of the emergent theory beyond the case studies, the development of a formal grounded theory was sought. This research revealed that the operations of the Tanzanian LGAs were constrained by factors such as deficient regulatory systems, political interference, donors’ influences, and funding uncertainties. These conditions forced the technocrats to use important accounting practices, such as budgeting, auditing, financial reporting, and performance measurement to manipulate the organisational legitimacy. The process of legitimacy manipulation ensured the availability of resources for the LGAs and the attainment of the individual interests of the Councils’ officials. This study contributes to the interpretive approach in emerging economies. Also, meta-coding, intra-relationships of categories, and development of formal grounded theory, add new insights to the grounded theory analysis. It is also worth noting that the study integrates the emergent theory within the New Institutional Sociology (NIS) framework. It was not intended to test NIS, but rather, to adopt it as a theoretical lens that assisted interpretation of the research findings. In the NIS framework, the study establishes the simultaneous achievement of legitimacy and efficiency, recognises multiple sources of loose coupling, and the influence of performance management on shaping accounting practices in the public sector organisations. It also offers the micro reactions of the Councils’ officials, and recognises the different patterns of the officials’ responses across Councils and service deliveries. The study argues that in emerging economies considerations of a country’s local contexts has the potential to minimise any counter-productivity of reform programs. Moreover, this research appeals for a holistic approach to the reform programs, harmonization of laws and regulations, the institution of efficient financial management and reporting mechanisms, and the improvement of employee welfare in the Tanzanian Councils.

Tidigare forskning pekar på att psykologiska faktorer påverkar hur individen rekryteras till en sekt. Förförståelsen inför denna intervjustudie var att det skulle kunna finnas ett behov av ett rehabiliteringscentrum i Sverige, och frågeställningen gällde vilka behov som föreligger hos en individ som lämnar en destruktiv sekt sett utifrån professionella hjälpares perspektiv. 14 personer deltog, psykiatriker, präster, politiker, terapeuter och psykologer. Resultatet visade att det finns olika anledningar till att individer rekryteras in i en sekt liksom till att de lämnar den. Resultatet visade också att det föreligger ett hjälpbehov hos individer som lämnar sekter och gemensamma svar för alla respondenter var att det behövs: (1) samtal, (2) gemenskap, (3) någon som lyssnar.

My research provided new information concerning the management, ecology, and conservation of greater sage-grouse (Centrocercus urophasianus). I report the results of an experiment using strategic intensive sheep grazing to enhance the quality of greater sage-grouse brood-rearing habitat. Although forb cover, an important component of brood-rearing habitat, responded positively to the grazing treatment, the response of other habitat variables was suppressed because the plots were not protected from domestic and wild herbivores during the years following the treatments. Measurements taken in grazing exclosures confirmed that herbivory by both large and small animals had significant impacts on vegetation. However, despite the suppressed habitat response, sage-grouse preferred the treated plots over the controls. In another chapter, I modeled survival rates of sage-grouse chicks to 42-days of age. Average chick survival across my study was high (39%). Survival varied across years and was affected by demographic, behavioral, and habitat factors. The top habitat model indicated that chick survival was positively related to grass cover and was higher in areas dominated by black sagebrush (Artemisia nova) than in big sagebrush (A. tridentata). The top model with demographic/behavioral factors indicated that survival was affected by interactions between hen age and brood mixing as well as between hatch date and brood mixing. In my last chapter I report on a survey of Utah sage-grouse hunter motivations and satisfaction. In 2008 and 2009 I surveyed over 600 sage-grouse hunters in Utah to determine why they chose to apply for sage-grouse hunting permits and what factors contributed to a satisfactory hunting experience. Originally, I had hypothesized that the impending Endangered Species Act listing petition for greater sage-grouse motivated hunters to pursue the species before they lost the opportunity. This hypothesis was not supported by the data. The majority of hunters indicated that they chose to hunt sage-grouse because it was a tradition or because it provided an opportunity to spend time outdoors with family. Additionally, Utah sage-grouse hunter satisfaction was influenced by whether or not the hunter was successful in harvesting at least one bird.

À l'échelle nanométrique, les particules métalliques présentent de nouvelles propriétés optiques liées au phénomène de résonance plasmon de surface. Une résonance plasmon est une oscillation collective et cohérente des électrons de conduction à la surface d'une nanoparticule métallique sous l'influence d'un champ électromagnétique extérieur. La longueur d'onde de cette résonance ainsi que la distribution spatiale du champ électromagnétique associé dépendent des caractéristiques de la nanoparticule (taille, forme et nature chimique), du milieu diélectrique hôte et de la géométrie d'illumination. L’excitation de plasmons de surface génère des champs électromagnétiques locaux de fortes intensités, localisés en des points spécifiques de la nanoparticule, appelés «points chauds». La lumière est ainsi miniaturisée et confinée dans des espaces de taille sub-longueur d’onde (<20nm). La possibilité de produire et de contrôler ces points chauds augure d'importantes réalisations dans un large éventail de domaines d'applications allant des technologies de l'information aux énergies renouvelables, tout en passant par la biomédecine. Ce travail de thèse met en évidence la possibilité de générer et de manipuler des points chauds au niveau de structures de taille nanométrique par effet de la géométrie de la nanostructure métallique ou bien de la configuration et de la longueur d’onde de la lumière excitatrice. L’objectif est de manipuler la lumière à petite échelle afin de contribuer au développement de nouvelles technologies d’origine plasmonique. A cet égard, les réponses optiques de nano-objets métalliques de différentes géométries et tailles, pris individuellement : cube, prisme… ou en groupes: dimère, chaîne… sont étudiées par microscopie de photoémission d'électrons PEEM (PhotoEmission Electron Microscopy), une technique de cartographie haute résolution (20 nm), non intrusive, permettant un adressage sélectif des modes plasmons.Par ailleurs et également dans le cadre de ce travail, une méthode analytique de description du champ proche optique, basée sur la théorie des groupes, a été développée. Cette méthode permet de prédire et d’interpréter en quelques minutes le comportement plasmonique d’une particule à 2D ou 3D, de symétrie finie ou non, seules ou en dimères, à partir des symétries de l’objet et du champ excitateur. En complément, des simulations numériques par la méthode des éléments frontières BEM (Boundary Element Method) ont été effectuées
At nanometer scale, the metallic particles exhibit new optical properties related to the surface plasmon resonance phenomenon. A plasmon resonance is a collective and coherent oscillation of the conduction electrons at a metallic nanoparticle surface under an external electromagnetic field. The resonance wavelength and the spatial distribution of the associated electromagnetic field depend on the nanoparticle characteristics (size, shape and chemical nature), the surrounding dielectric medium and the illumination geometry.The excitation of surface plasmons generates local electromagnetic fields of high intensity located at specific points of the nanoparticle called "hot spots". The light is miniaturized and confined in sub-wavelength areas (<20 nm). The ability to produce and control hot spots holds great promise for a large range of applications from information technology to renewable energies and biomedicine. This thesis highlights the possibility of generating and manipulating hot spots in nanostructures throughout the particle geometry or/and the configuration and wavelength of the exciting light. To do this, the optical response of various metallic nano-objects of different geometries and sizes, taken individually: cube, prism ... or in groups: dimer, chain ... are studied by PhotoEmission Electron Microscopy (PEEM), a non-intrusive and high resolution (20 nm) mapping technique allowing a selective addressing of plasmons modes. In addition to this experimental investigation, the search for a specific optical near-field distribution is also carried out using group theory. We developed an original theoretical method allowing to predict in a few minutes the plasmonic response of a 2D or 3D particle, of finite or infinite symmetry, alone or in dimer, from the object and exciting field symmetries. In parallel, numerical simulations using the Boundary Element Method (BEM) have been carried out

The greater sage-grouse (Centrocercus urophasianus; sage-grouse) has been a species of conservation concern since the early 20th century due to range-wide population declines. To contribute to knowledge of the ecology of sage-grouse populations that inhabit the Box Elder Sage Grouse Management Area (SGMA) in northwestern Utah and quantify their responses to landscape scale habitat manipulations, I monitored vital rates and habitat selection of 45 female sage-grouse from 2014 to 2015. Using telemetry locations of female sage-grouse with known nest and brood fates, I created Generalized Linear Mixed Models to estimate the influence of proximity to pinyon (Pinus spp.) and juniper (Juniperus spp.; conifer) encroachment, and removal projects may have on sagegrouse reproductive fitness in the Box Elder SGMA. The best fit model suggested that for every 1 km a nest was located away from a conifer removal area, probability of nest success was reduced by 9.1% (β = -0.096, P < 0.05). Similarly, for every 1 unit increase in the log-odds of selection for distance to treatment, probability of brood success declined by 52.6% (P = 0.09). The probability of brood success declined by 77.2% (P < 0.05) as selection for conifer canopy cover increased. To evaluate sage-grouse habitat use, I used fecal pellet surveys to estimate relative pellet density in conifer encroachment, removal, and undisturbed sagebrush areas. Sage-grouse pellet densities were estimated at 4.6 pellets/ha (95% CI = 1.2, 10.9), 8.6 pellets/ha (95% CI = 3.8, 15.2), and 50.6 pellets/ha (95% CI = 36.8, 69.6), in conifer encroachment, removal, and undisturbed sagebrush areas respectively. Density estimates did not statistically differ between conifer encroachment and removal areas. To determine if vegetation micro-site characteristics at sage-grouse use sites influenced nest or brood fate, I recorded standard vegetation measurements for all radio-marked sage-grouse nests and a stratified random sample of brood-use sites from 2014- 2015 and compared them to random sites. Micro-site vegetation characteristics measured did not differ for successful and unsuccessful nests. Many characteristics differed between micro-sites used by successful broods and those used by unsuccessful broods. Sites used by successful broods also differed from random sites.

This exploratory qualitative study used grounded theory to investigate the anatomy of educational apps that contain virtual manipulatives. For this study 100 virtual manipulatives within educational apps designed for the iPad were observed by the researcher in order to expand the explanations of and build theory about virtual manipulatives within apps. Affordance theory was used to frame all six phases of the study in which the researcher identified virtual manipulatives situated within educational apps, conducted observer-as-participant structured and unstructured observations, analyzed component data including field notes and memos using open and axial coding, created a conceptual framework, developed an evaluation tool prototype to evaluate virtual manipulatives within educational apps, and used the evaluation tool prototype to evaluate additional virtual manipulatives within educational apps. The constant comparative method of open and axial coding was used to analyze the observation data that included field notes, memos, and video recordings. This indepth qualitative analysis led to the emergence of six study results concerning the components and relationships within educational apps that contain virtual manipulatives. The results revealed that: (1) virtual manipulatives within apps are comprised of two components: dynamic mathematical objects and features; (2) there are three distinct types of dynamic mathematical objects; (3) there are eight categories of features; (4) within one virtual manipulative there can be one or multiple objects; (5) varying relationships can exist among the dynamic object and the features within a virtual manipulative; and (6) varying relationships can exist among the virtual manipulatives within an education app in terms of the number, type, and ways the user proceeds. A conceptual framework was also developed during the study to illustrate the components and relationships that emerged from the analysis and to serve as the basis for the development of an evaluation tool prototype to evaluate educational apps that contain virtual manipulatives. The components, relationships, framework, and evaluation tool prototype developed during this study advance the literature on virtual manipulatives and provide researchers with a common language to evaluate these apps.

The purpose of this thesis is to study the personal problems that can occur when defecting from a destructive cult, and what kind of support you may need from social authorities. The aim is to develop guidelines for social workers who are in contact with sect defectors. It’s a qualitative study based on interviews with six defectors from Jehovah’s witnesses. The results shows that all the defectors that have been interviewed have had anxiety problems, lost contact with friends and relatives, low level of education, and low self esteem when defecting or after. Most respondents have reported that they have had thoughts of suicide. It also occurs that respondents have had eating disorders, psychosomatic problems, drug abuse, lack of knowledge about society and have felt threatened and harassed in connection with the defection. These psychosocial problems that have been ascertained to constitute areas where social authorities should aid sect defectors. In accordance with the purpose of this thesis, guidelines are formed for social workers.

Syftet med undersökningen är att undersöka den personliga problematik som kan uppstå vid avhopp från en destruktiv sekt och de behov av stöd och hjälp man kan behöva ha från sociala myndigheter. Avsikten med studien är att försöka utveckla vägledande anvisningar för socialarbetare som kommer i kontakt med avhoppare. Det är en kvalitativ studie baserad på intervjuer med sex avhoppare från Jehovas vittnen. Resultatet visar att alla de avhoppare som intervjuats hade haft ångestproblematik, förlorat kontakt med vänner och familj, låg utbildningsnivå samt svag självkänsla i samband med avhoppet eller där efter. De flesta respondenterna sagt sig ha haft självmordstankar. Det förekommer även att respondenter säger sig ha haft ätstörningar, psykosomatisk problematik, narkotikamissbruk, bristande kunskap om samhället samt känt sig hotade och trakasserade i samband med avhoppet. De psykosociala problem som intervjupersonerna berättar om liknar det som tidigare studier funnit och som utgör områden där sociala myndigheter bör bistå sektavhoppare. I enlighet med syftet är slutligen vägledande anvisningar utformade för socialarbetare.

付記する学位プログラム名: デザイン学大学院連携プログラム
Kyoto University (京都大学)
0048
新制・課程博士
博士(工学)
甲第21759号
工博第4576号
新制||工||1713(附属図書館)
京都大学大学院工学研究科機械理工学専攻
(主査)教授 松野 文俊, 教授 椹木 哲夫, 教授 小森 雅晴
学位規則第4条第1項該当

Syftet med studien var att se om psykiskt välbefinnande hos avhoppare från sekter är relaterat till förekomsten av psykiska övergrepp i den rörelse som lämnats samt att undersöka hur avhoppares psykiska välbefinnande ser ut. Deltagare var 57 avhoppare från åtta olika religiösa rörelser i Sverige. De rekryterades huvudsakligen genom hjälporganisationer för avhoppare och deltog genom att svara på frågor via ett nätformulär. Resultaten visade att högre förekomst av psykiska övergrepp, mätt med GPA-skalan, var relaterat till sämre psykiskt välbefinnande, mätt med CORE-OM, vilket var enligt hypotesen. Det fanns däremot inte något samband mellan psykiskt välbefinnande och antalet år i rörelsen eller antalet år sedan avhoppet. Vidare framkom att avhoppare har sämre psykiskt välbefinnande än normalbefolkningen, vilket var enligt hypotesen, där högt riskbeteende var utmärkande. Ett förslag till slutsats är att sämre psykiskt välbefinnande hos avhoppare till stor del orsakas av psykiska övergrepp som förekommit i rörelsen. Vidare indikerar resultaten att vården bör vara observant på riskbeteende hos denna patientgrupp samt att avhoppare skulle vara hjälpta av större kunskap hos vårdpersonal om sektmiljöer.
The aim of this study was to examine if psychological well-being among ex-cult members is related to the extent of psychological abuse in the group, and to investigate the level and characteristics of their psychological well-being. Participants were 57 ex-cult members from eight different Swedish religious groups, who were primarily recruited from organizations for ex-cult members. They participated by answering an internet questionnaire. The results showed that higher levels of psychological abuse, measured with the GPA-scale, was related to lower levels of psychological well-being, measured with the CORE-OM, which supported the hypothesis. On the other hand, no relation was found between psychological well-being and the number of years in the group or the number of years since leaving the group. Furthermore it was found that ex-cult members have a lower level of psychological well-being than the normal population, which was in accordance with the hypothesis, in particular showing an elevated risk behaviour. The suggested conclusion is that low psychological well-being among ex-cult members is to a great extent caused by psychological abuse in the group. The results also indicate that personnel in health care should be aware of risk behaviour among these patients and that ex-cult members would benefit from better insight in cult environments by personnel in health care.

L’évolution technologique du web durant ces dernières années a favorisé l’arrivée d’environnements virtuels collaboratifs pour la modélisation 3D à grande échelle. Alors que la collaboration réunit dans un même espace partagé des utilisateurs distants géographiquement pour un objectif de collaboration commun, les ressources matérielles qu'ils apportent (calcul, stockage, 3D ...) avec leurs connaissances sont encore trop rarement utilisées et cela constitue un défi. Il s'agit en effet de proposer un système simple, performant et transparent pour les utilisateurs afin de permettre une collaboration efficace à la fois sur le volet computationnel mais aussi, bien entendu, sur l'aspect métier lié à la modélisation 3D sur le web. Pour rendre efficace le passage à l’échelle, de nombreux systèmes utilisent une architecture réseau dite "hybride", combinant client serveur et pair-à-pair. La réplication optimiste s'adapte bien aux propriétés de ces environnements répartis : la dynamicité des utilisateurs et leur nombre, le type de donnée traitées (3D) et leur taille. Cette thèse présente un modèle pour les systèmes d’édition collaborative en 3D sur le web. L'architecture cliente (3DEvent) permet de déporter les aspects métiers de la 3D au plus près de l’utilisateur sous la forme d’évènements. Cette architecture orientée événements repose sur le constat d’un fort besoin de traçabilité et d’historique sur les données 3D lors de l’assemblage d’un modèle. Cet aspect est porté intrinsèquement par le patron de conception event-sourcing. Ce modèle est complété par la définition d’un intergiciel en pair-à-pair. Sur ce dernier point, nous proposons d'utiliser la technologie WebRTC qui présente une API familière aux développeurs de services en infonuagique. Une évaluation portant sur deux études utilisateur concernant l’acceptance du modèle proposé a été menée dans le cadre de tâches d’assemblage de modèles 3D sur plusieurs groupes d’utilisateurs
Web technologies evolutions during last decades fostered the development of collaborative virtual environments for 3D design at large scale. Despite the fact that collaborative environments gather in a same shared space geographically distant users in a common objective, the hardware ressources of their clients (calcul, storage, graphics ...) are often underused because of the challenge it represents. It is indeed a matter of offering an easy-to-use, efficient and transparent collaborative system to the user supporting both computationnal and 3D design visualisation and business logic needs in heterogeneous web environments. To scale well, numerous systems use a network architecture called "hybrid", combining both client-server and peer-to-peer. Optimistic replication is well adapted to distributed application such as 3D collaborative envionments : the dynamicity of users and their numbers, the 3D data type used and the large amount and size of it.This document presents a model for 3D web-based collaborative editing systems. This model integrates 3DEvent, an client-based architecture allowing us to bring 3D business logic closer to the user using events. Indeed, the need of traceability and history awareness is required during 3D design especially when several experts are involved during the process. This aspect is intrinsec to event-sourcing design pattern. This architecture is completed by a peer-to-peer middleware responsible for the synchronisation and the consistency of the system. To implement it, we propose to use the recent web standard API called WebRTC, close to cloud development services know by developers. To evaluate the model, two user studies were conducted on several group of users concerning its responsiveness and the acceptance by users in the frame of cooperative assembly tasks of 3D models

This thesis consists of three essays in the field of information economics. The first essay studies manipulation of information by partisan media. The recent increase in partisan media has generated interest in what drives media outlets to become more partisan. I develop a model to study the role of diffusion of information by word of mouth. In the model, a media outlet designs an information policy, which specifies the level of partisan slant in the outlet’s news reports. The news spread via a communication chain in a population of agents with heterogeneous preferences. The slant has an impact on whether the agents find the news credible and on their incentives to pass the news to others. The analysis elucidates how partisanship of media can be driven by political polarisation of the public and by the tendency of people to interact with people with similar political views. The second essay, co-authored by Jakub Redlicki, investigates falsification of scientific evidence by interest groups. We analyse a game between a biased sender (an interest group) and a decision maker (a policy maker) where the former can falsify scientific evidence at a cost. The sender observes scientific evidence and knows that it will also be observed by the decision maker unless he falsifies it. If he falsifies, then there is a chance that the decision maker observes the falsified evidence rather than the true scientific evidence. First, we investigate the decision maker’s incentives to privately acquire independent evidence, which not only provides additional information to her but can also strengthen or weaken the sender’s falsification effort. Second, we analyse the decision maker’s incentives to acquire information from the sender. The third essay analyses competition between interest groups for access to a policy maker. I study a model of lobbying in which two privately-informed experts (e.g., interest groups) with opposite goals compete for the opportunity to communicate with a policy maker. The main objective is to analyse the benefits which competition for access brings to the policy maker as opposed to hiring an expert in advance. I show that competition for access is advantageous in that it provides the policy maker with some information about the expert who did not gain access and gives the experts an incentive to invest in their communication skills. On the other hand, hiring an expert in advance allows the policy maker to use a monetary reward to incentivise the expert to invest more in his communication skills.

The maintenance of downed woody debris supplies is increasingly being recognized as an integral part of forest management. In order to better manage this resource, it is important to assess its role in supporting biodiversity. In this thesis, I investigate the responses of carabid communities to variation in woody debris availability in an experimental manipulation of woody debris volume in closed canopy forests and following a biomass harvest in a clearcut. Within closed-canopy forests, total carabid abundance and the abundances of eight species increased significantly with increasing volumes of various types of woody debris, particularly large diameter, late-decay conifer wood. Similarly, a strong affinity with woody debris was observed in the clearcut. These findings suggest that reductions in woody debris will have negative consequences for carabids and indicate the need to ensure a diverse and abundant supply of woody debris during stand development.

The thesis focuses on several key issues associated with modeling, analysis, and advanced control of a class of multi-module manipulator systems, which can vary their geometric configuration to quickly adapt to the environment and the requirements of a task. The studied manipulator system has a combination of revolute and prismatic joints, which lends itself to distinct advantages; for example, reduced dynamic coupling effects and singularities, simpler kinematics, and ease of obstacle avoidance , for a specific number of degrees of freedom. In rigorous and hazardous environments, autonomous operation is preferred. A reliable and effective control approach is essential to properly carry out a task (e.g., trajectory tracking in parts joining, inspection and material application; satellite capturing for retrieval and repair) in an autonomous manner. In the present work, several controllers have been formulated, analyzed, designed, simulated, and tested. Specifically, linear quadratic regulator (LQR), feedback linearization technique (FLT), computed torque adaptive control, and neural network adaptive control, have been studied. Most of them are model-based controllers. In view of this and for use of computer simulations related to illustration and evaluation of the techniques developed in the thesis, complete dynamic formulations of ground-based and space-based models of the robotic system are presented in the thesis. The resulting coupled and nonlinear models may be incomplete and may have uncertainties in parameters. The neural-network adaptive controller developed here is able to accommodate these shortcomings. Details of this controller are presented and the performance is evaluated using several case studies. The various control methods studied in the present research have distinct advantages and disadvantages, which make them perform satisfactorily under some conditions while deteriorating under some other conditions. As a result it is desirable to have a supervisory system to monitor the performance of the robotic system and then switch on an appropriate control scheme depending on the system behavior. When the system operates in different modes of operation or carries out several tasks, then, it would be possible to optimize its performance through controller switching. A new control scheme termed Supervisory Control Switching System (SCSS) has been developed and evaluated during the concluding stage of the present investigation. It is capable of selecting the most suitable controller for a particular task or a situation, from several separately designed controllers. The present study lays a sound foundation for further exploration of this class of novel and useful manipulators
Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate

As the size of Software development projects increase, so too do the number of people working on these projects. This increase of software groups have brought about a new focus on the sociological issues associated with Software Development. There is a growing body of work that seeks to understand how Software Engineers work together effectively as a group, and also to identify factors that enable increased productivity consistently. Social Psychology looks at the interactions between individuals in groups (group dynamics) and may provide an applicable means to address this increased need for enhanced group effectiveness in Software Engineering. The thesis of this research is that it is possible to apply Social Psychology research (in particular Normative Manipulation) to Software Engineering groups. It is possible to use Normative Manipulation effectively to increase the performance of Software Engineering groups in some types of tasks, and finally, this technique is adoptable by practising Software Engineering groups as it is non-intrusive. Normative Manipulation is a technique in which particular behaviours are made to be favoured by group members. This behaviour is then actively practised by all group members. These particular behaviours may in turn increase the effectiveness of groups on particular tasks - for instance, a group favouring the behaviour of objectivity would then be more inclined to assess provided on information its logical merits and may then in turn be more likely to uncover other related, but less obvious information. Since the success of elicitation and specification of Software Requirements is related to how complete the produced specification is, then it follows that such a group could possibly have increased performance in Software Elicitation and Specification tasks. We demonstrate the validity of the thesis claims by performing three studies. The first study attempts to replicate the results of a Social Psychology experiment on a sample of participants drawn from a Software Engineering population. The second study attempts to show that it is possible to affect the effectiveness of Requirements Elicitation by Software Engineering groups by instilling different norms. The third study applies Normative Manipulation on a practising Software Group to identify if the technique can be applied transparently as part of a normal Requirements Elicitation task. -- provided by Candidate.

Image manipulation is subverting the credibility of photographs as a whole. Currently there is no practical solution for asserting the authenticity of a photograph. People express their concern about this when asked but continue to operate in a ‘business as usual’ fashion. While a range of digital forensic technologies has been developed to address falsification of digital photographs, such technologies begin with ‘sourceless’ images and conclude with results in equivocal terms of probability, while not addressing the meaning and content contained within the image. It is interesting that there is extensive research into computer-based image forgery detection, but very little research into how we as humans perceive, or fail to perceive, these forgeries when we view them. The survey, eye-gaze tracking experiments and neural network analysis undertaken in this research contribute to this limited pool of knowledge. The research described in this thesis investigates human perceptions of images that are manipulated and, by comparison, images that are not manipulated. The data collected, and their analyses, demonstrate that humans are poor at identifying that an image has been manipulated. I consider some of the implications of digital image manipulation, explore current approaches to image credibility, and present a potential digital image authentication framework that uses technology and tools that exploit social factors such as reputation and trust to create a framework for technologically packaging/wrapping images with social assertions of authenticity, and surfaced metadata information. The thesis is organised into 6 chapters. Chapter 1: Introduction I briefly introduce the history of photography, highlighting its importance as reportage, and discuss how it has changed from its introduction in the early 19th century to today. I discuss photo manipulation and consider how it has changed along with photography. I describe the relevant literature on the subject of image authentication and the use of eye gaze tracking and neural nets in identifying the role of human vision in image manipulation detection, and I describe my area of research within this context. Chapter 2: Literature review I describe the various types of image manipulation, giving examples, and then canvas the literature to describe the landscape of image manipulation problems and extant solutions, namely: • the nature of image manipulation, • investigations of human perceptions of image manipulation, • eye gaze tracking and manipulated images, • known efforts to create solutions to the problem of preserving unadulterated photographic representations and the meanings they hold. Finally, I position my research activities within the context of the literature. Chapter 3: The research I describe the survey and experiments I undertook to investigate attitudes toward image manipulation, research human perceptions of manipulated and unmanipulated images, and to trial elements of a new wrapper-style file format that I call .msci (mobile self-contained image), designed to address image authenticity issues. Methods, results and discussion for each element are presented in both explanatory text and by presentation of papers resulting from the experiments. Chapter 4: Analysis of eye gaze data using classification neural networks I describe pattern classifying neural network analysis applied to selected data obtained from the experiments and the insights this analysis provided into the opaque realm of cognitive perception as seen through the lens of eye gaze. Chapter 5: Discussion I synthesise and discuss the outcomes of the survey and experiments. I discuss the outcomes of this research, and consider the need for a distinction between photographs and photo art. I offer a theoretical formula within which the overall authenticity of an image can be assessed. In addition I present a potential image authentication framework built around the .msci file format, designed in consideration of my investigation of the requirements of the image manipulation problem space and the experimental work undertaken in this research. Chapter 6: Conclusions and future work This thesis concludes with a summary of the outcomes of my research, and I consider the need for future experimentation to expand on the insights gained to date. I also note some ways forward to develop an image authentication framework to address the ongoing problem of image authenticity.

All-optical devices have attracted many research interests due to their ultimately low heat dissipation compared to conventional devices based on electric-optical conversion. With recent advances in nonlinear optics, it is now possible to design the optical properties of a medium via all-optical nonlinear effects in a table-top device or even on a chip.

In this thesis, I realize all-optical control of the optical group velocity using the nonlinear process of stimulated Brillouin scattering (SBS) in optical fibers. The SBS-based techniques generally require very low pump power and offer a wide transparent window and a large tunable range. Moreover, my invention of the arbitrary SBS resonance tailoring technique enables engineering of the optical properties to optimize desired function performance,

which has made the SBS techniques particularly widely adapted for

various applications.

I demonstrate theoretically and experimentally how the all-optical

control of group velocity is achieved using SBS in optical fibers.

Particularly, I demonstrate that the frequency dependence of the

wavevector experienced by the signal beam can be tailored using

multi-line and broadband pump beams in the SBS process. Based on the theoretical framework, I engineer the spectral profile

to achieve two different application goals: a uniform low group velocity (slow light) within a broadband spectrum, and a group velocity with a linear dependence on the frequency detuning (group velocity dispersion or GVD).

In the broadband SBS slow light experiment, I develop a novel noise current modulation method that arbitrarily tailors the spectrum of a diode laser. Applying this method, I obtain a 5-GHz broadband SBS gain with optimized flat-topped profile, in comparison to the ~40 MHz natural linewidth of the SBS resonance. Based on the broadband SBS resonance, I build a 5-GHz optical buffer and use this optical buffer to delay a return-to-zero data sequence of rate 2.5 GHz (pulse width 200 ps). The fast noise modulation method significantly stabilizes the SBS gain and improves the signal fidelity. I obtain a tunable delay up to one pulse-width with a peak signal-to-noise ratio of 7. I also find that SBS slow light performance can be improved by avoiding competing nonlinear effects. A gain-bandwidth product of 344 dB.GHz is obtained in our system with a highly-nonlinear optical fiber.

Besides the slow light applications, I realize that group velocity dispersion is also optically controlled via the SBS process. In the very recent GVD experiment, I use a dual-line SBS resonance and obtain a tunable GVD parameter of 7.5 ns$^2$/m, which is 10$^9$ times larger than the value found in a single-mode fiber. The large GVD system is used to disperse an optical pulse with a pulse width of 28 ns, which is beyond the capability for current dispersion techniques working in the picosecond and sub picosecond region. The SBS-based all-optical control of GVD is also widely tunable and can

be applied to any wavelength within the transparent window of the

optical fiber. I expect many future extensions following this work

on the SBS-based all-optical GVD control using the readily developed SBS tailoring techniques.

Finally, I extend the basic theory of backwards SBS to describe the forward SBS observed in a highly nonlinear fiber, where asymmetric forward SBS resonances are observed at the gigahertz range. An especially large gain coefficient of 34.7 W$^{-1}$ is observed at the resonance frequency of 933.8 MHz. This is due to good overlap between the optical wave and the high order guided radial acoustic wave. The interplay from the competing process known as the Kerr effect is also accounted for in the theory.

Dissertation

Atualmente a natureza competitiva da prática esportiva cria demandas constantes de tecnologias e opções terapêuticas que possam influenciar o desempenho desportivo. De acordo com a literatura, observa se um crescente interesse sobre os efeitos da Terapia de Manipulação Vertebral (TMV) no desempenho desportivo. O foco é melhorar as capacidades individuais em termos de proficiência e consistência de técnicas, especialmente em relação à simetria na performance física. Este foco contribui para melhorar o conhecimento sobre as capacidades individuais, através da triagem de condições músculo-esqueléticas, nomeadamente nas assimetrias bilaterais, que podem influenciar negativamente parâmetros mecânicos e fisiológicos, afetando potencialmente o desempenho esportivo. Isso requer uma avaliação precisa e confiável de simetria em termos de testes de desempenho físico em ações estáticas, dinâmicas e explosivas. Para atingir esses objetivos na concretização desta dissertação foram realizados três estudos. No primeiro estudo, o estudo preliminar, a simetria de atletas assintomáticos foi medida através de testes de desempenho sobre plataforma de força e com instrumentos de captura de movimento, para avaliar a viabilidade do estudo em medir as mudanças imediatas da terapia de manipulação lombar na simetria, através dos testes: postura estática, agachamento e salto vertical contramovimento. O segundo estudo, estudo prospetivo teste e re-teste foi desenvolvido para estabelecer a fiabilidade intra-avaliador, intra-sessão das medidas de simetria entre a intervenção experimental lombar TMV. Através de dois índices de simetria e de cálculos estatísticos aprofundados, a fiabilidade e reprodutibilidade das medidas foram avaliados neste estudo. O estudo final, o ensaio clínico randomizado controlado, avaliou os efeitos imediatos de uma única sessão de intervenção terapêutica, na simetria de atletas assintomáticos. Os parâmetros biomecânicos cinéticos e cinemáticos foram medidos através de duas plataformas de força, instrumentos de captura de movimento e softwares de processamento e análise dos dados. Neste estudo foram aplicados dois índices de simetria para obter valores globais de simetria nos testes de desempenho, pré e pós as intervenções experimentais TMV e SHAM. Com base nos resultados obtidos desses estudos, o protocolo metodológico demonstrou ser viável e fiável em medir os efeitos da manipulação lombar na simetria cinética e cinemática, antes e depois das intervenções terapêuticas. Em 90% das variáveis do estudo, os resultados apresentaram boa e excelente confiabilidade absoluta e relativa, e uma pequena manifestação dos erros das medidas, confirmando a assim confiabilidade, reprodutibilidade e a precisão das medidas, em relação às variáveis propostas na nossa investigação. x Nossos achados sugerem que a estratégia terapêutica de correção das disfunções vertebrais lombares através da terapia de manipulação vertebral, produz efeitos imediatos na simetria estática em postura ortostática bipedal. Em relação às ações dinâmicas, a intervenção lombar TMV não apresentou efeito imediato significativo na simetria em ambos os grupos de atletas assintomáticos. Portanto, nossos resultados demonstram uma melhoria imediata somente na simetria cinética bilateral em postura estática, nomeadamente nas forças de reação ao solo bilateral. Esses achados sugerem que este protocolo metodológico apresentado nesta tese, apresenta informações relevantes e fidedignas e pode servir como uma ferramenta útil para medir, tratar e avaliar os padrões de simetria cinética no desempenho de atletas assintomáticos, podendo assim também ser significativo no contexto clínico, desportivo e de investigação científica.
The competitive nature of sports practice creates constant demands for technologies and therapeutic options that could influence sports performance. An increasing interest on this theme have been found on literature interventional between sports professionals, clinicians and athletes regarding SMT effects on sports performance. The focus is to enhance individual capabilities in terms of proficiency and consistency of techniques, especially relative to physical performance. This focus contributes to improve knowledge about individual capabilities, through screening of musculoskeletal conditions, such bilateral asymmetries, that could negatively influence a range of mechanical and physiological parameters and consequently athlete’s performance. This requires an accurate and reliable assessment of symmetry in terms of overall functional performance tests. In this stand, to achieve this goals, three studies were conducted. In the first study, the preliminary feasibility study, were measure kinetic symmetry by index with asymptomatic athletes over force platform, and motion capture instrument, to quantitatively evaluated the feasibility of the study to measure the immediate effects of lumbar SMT on symmetry in asymptomatic athletes, through use of physical performance tests: static posture, squat movement, and countermovement. The second study, prospective intra-rater, test-retest reliability study, were applied to establish the physical performance tests reliability, reproducibility of kinetic and kinematic symmetry measurements between lumbar SMT intervention through deep statistics evaluations. The final study, randomized controlled trial with two groups of asymptomatic athletes and two symmetry indexes were utilized to measure the kinematic and kinematic biomechanical parameters by force platform, and motion capture instruments, performing physical performance tests: static posture, squat movement, and countermovement. Based on the obtained results of these studies, our findings suggest that a therapeutic strategy of correcting the lumbar vertebral dysfunctions through lumbar spinal manipulation produce immediately changes of neuro-musculoskeletal system, namely in kinetic symmetry (bilateral lower limbs reaction forces) in static posture. Relative to dynamic trials, lumbar intervention not presented significant immediate effect on symmetry in both group of asymptomatic athlete’s participants. Good to excellent relative reliability were found in 90% of the variables and small manifestation of measurements errors, in all verified variables, confirming study confidence relative to the variables. Thus, our results demonstrated immediate improvement of bilateral kinetic symmetry in static posture trials, thus appear to be clinically and sportive meaningful. XII These findings suggest that this methodological protocol may be a useful tool to assess physical performance by kinetic and kinematic symmetry in a clinical and sportive context. Keywords