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We present results studying the distribution and properties of the diffuse dust in the Milky Way Galaxy using large optical surveys—specifically, the Sloan Digital Sky Survey (SDSS) and the Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS1). This work has resulted in accurate measurements of dust reddening in regions of low extinction over large regions of sky. We present maps of reddening from dust covering the footprint of the SDSS, which covers one quarter of the sky. We present preliminary maps of dust covering the Pan-STARRS1 footprint, which covers three-quarters of the sky, including most of the plane of our Galaxy. We use these maps of dust to decisively exclude some simple parameterizations of dust extinction (Cardelli et al., 1989) in favor of others (Fitzpatrick, 1999). We show that the extinction predicted by the widely-used far-infrared dust map of Schlegel et al. (1998) is overestimated by 18%, and recalibrate that map using our extinction measurements. We further map variation in the properties of the dust, as indicated by variation in the amount of extinction relative to the amout of far-infrared dust extinction, and by variation in the ratio of dust extinction at different frequencies. We confirm these results by measuring reddening using two independent techniques and data sets, the SDSS photometry and spectroscopy. We further present the photometric calibration of the Pan-STARRS1 data—a necessary step to studying the dust with that ongoing survey. We achieve photometric precision unprecedented in a large optical survey, accurate to better than 1%. We additionally show the suitability of the calibrated photometry for studying the distribution of dust. Finally, we present preliminary three-dimensional maps of the dust in the Galaxy using our calibrated data from Pan-STARRS1. These maps will provide by far the most extensive information yet achieved about the three-dimensional distribution of extinction in the Galaxy. / Physics

Water distribution system modeling can be used as a basis of planning and operation decisions. However, model accuracy and uncertainty will impact the model based decisions. Model prediction uncertainty results from uncertainty in model parameters that are determined through calibration or are based upon modeler judgment. The focus of this dissertation is the effect of uncertainties on water quality model estimates and calibration. The dissertation is centered around three journal articles and a technical note.In the first paper, the effect of parameter uncertainty on water quality in a distribution system under steady and unsteady conditions was analyzed by Monte Carlo simulation (MCS). Sources of uncertainties for water quality include decay coefficients, pipe diameter and roughness, and nodal spatial and temporal demands. The effect of individual parameter is discussed, as well as the combined effect of the parameters. It also describes the effect of flow patterns.A general calibration model is developed in the second paper for identifying wall decay coefficients. The problem is solved using the SFLA optimization algorithm that is coupled with hydraulic and water quality simulation models using the EPANET toolkit. The methodology is applied on two application networks. The study presents the effect of different field conditions such as the network with or without tanks, altering disinfectant injection policies, changing measurement locations, and varying the number of global wall decay coefficient on the estimated parameters. The numerical study also discusses whether the complexity of the system can be captured with fewer than the actual number of field parameters and if the number of the measurement locations is sufficient.The third paper conducts a study that considers a full calibration assessment for a water quality model in the distribution systems. The calibration process begins with estimating the the best fit wall decay coefficients. Next, the uncertainties involved with estimated parameters are calculated. Finally, the study assesses the model prediction uncertainties for critical demand conditions due to the parameter uncertainties. Various conditions are evaluated including the effects of different measurement errors and different measurement conditions on the uncertainty levels of estimated parameters as well as on the model predictions.Fourth paper presents study in which a booster disinfectant is introduced within a distribution system to maintain disinfectant residuals and avoid high dosages at water sources. Assuming that first order reaction kinetics apply to chlorine decay, an integer linear programming optimization problem is posed to booster locations and their injection rates. The formulation avoids long water quality simulations by adding constraints requiring the concentrations at the beginning and end of the design period to be the same. The optimization problem is divided into two levels. The upper level selects the booster locations using a genetic algorithm, if more than a few boosters are included, or enumeration, if the number of boosters and/or potential locations is relatively small. Given a set of boosters from the upper level, the lower level minimizes the chlorine mass to be injected to maintain required residuals. The approach is applied to the Brushy Plains system for alternative numbers of allowable boosters.

In most regions of the world, and particularly in developing countries, the possibility and reliability of hydrologic predictions is severely limited, because conventional measurement networks (e.g. rain and stream gauges) are either nonexistent or sparsely located. This study, therefore, investigates various systems methods and newly available data acquisition techniques to evaluate their potential for improving hydrologic predictions in poorly gaged and ungaged watersheds.Part One of this study explores the utility of satellite-remote-sensing-based rainfall estimates for watershed-scale hydrologic modeling at watersheds in the Southeastern U.S. The results indicate that satellite-based rainfall estimates may contain significant bias which varies with watershed size and location. This bias, of course, then propagates into the hydrologic model simulations. However, model performance in large basins can be significantly improved if short-term streamflow observations are available for model calibration.Part Two of this study deals with the fact that hydrologic predictions in poorly gauged/ungauged watersheds rely strongly on a priori estimates of the model parameters derived from observable watershed characteristics. Two different investigations of the reliability of a priori parameter estimates for the distributed HL-DHMS model were conducted. First, a multi-criteria penalty function framework was formulated to assess the degree of agreement between the information content (about model parameters) contained in the precipitation-streamflow observational data set and that given by the a priori parameter estimates. The calibration includes a novel approach to handling spatially distributed parameters and streamflow measurement errors. The results indicated the existence of a significant trade-off between the ability to maintain reasonable model performance while maintaining the parameters close to their a priori values. The analysis indicates those parameters responsible for this discrepancy so that corrective measures can be devised. Second, a diagnostic approach to model performance assessment was developed based on a hierarchical conceptualization of the major functions of any watershed system. "Signature measures" are proposed that effectively extract the information about various watershed functions contained in the streamflow observations. Manual and automated approaches to the diagnostic model evaluation were explored and were found to be valuable in constraining the range of parameter sets while maintaining conceptual consistency of the model.

The rapid growth of the market for short-range wireless devices, with standards such as Bluetooth and Wireless LAN (IEEE 802.11) being the most important, has created a need for highly integrated transceivers that target drastic power and area reduction while providing a high level of integration. The radio section of the devices designed to establish communications using these standards is the limiting factor for the power reduction efforts. A key building block in a transceiver is the frequency synthesizer, since it operates at the highest frequency of the system and consumes a very large portion of the total power in the radio. This dissertation presents the basic theory and a design methodology of frequency synthesizers targeted for short-range wireless applications. Three different examples of synthesizers are presented. First a frequency synthesizer integrated in a Bluetooth receiver fabricated in 0.35μm CMOS technology. The receiver uses a low-IF architecture to downconvert the incoming Bluetooth signal to 2MHz. The second synthesizer is integrated within a dual-mode receiver capable of processing signals of the Bluetooth and Wireless LAN (IEEE 802.11b) standards. It is implemented in BiCMOS technology and operates the voltage controlled oscillator at twice the required frequency to generate quadrature signals through a divide-by-two circuit. A phase switching prescaler is featured in the synthesizer. A large capacitance is integrated on-chip using a capacitance multiplier circuit that provides a drastic area reduction while adding a negligible phase noise contribution. The third synthesizer is an extension of the second example. The operation range of the VCO is extended to cover a frequency band from 4.8GHz to 5.85GHz. By doing this, the synthesizer is capable of generating LO signals for Bluetooth and IEEE 802.11a, b and g standards. The quadrature output of the 5 - 6 GHz signal is generated through a first order RC - CR network with an automatic calibration loop. The loop uses a high frequency phase detector to measure the deviation from the 90° separation between the I and Q branches and implements an algorithm to minimize the phase errors between the I and Q branches and their differential counterparts.

This literature study concerned the use and function of the radioactive isotope carbon-14, as a dating method of organic material, within the scientific field of physical geography. In this report it is presented the need of atmospheric calibration curves and the development of these as a necessity to translate carbon-14 years to calibrated calendar years. A number of common age-depth models that is used to give an approximation of an accumulation sequence and its related dates over the actual time period in different natural archives is presented and discussed. Different problems that commonly occur when age-depth models are utilized as for instance reservoir effects, contaminations or other age deviations are addressed and analyzed. The software CLAM in presented and discussed and was also used to produce age-depth models. In order to test the impact of different age-depth models used to date the immigration of Picea Abies in the Swedish landscape during Holocene, five lake sediment cores and their pollen profiles was remodeled using CLAM. The outcome of the remodeling suggest that the impact of choosing “wrong” age-depth model was of little importance for these chosen lakes, as the deviating ages between the statistically best and the statistically worst model, was just 2% on average. Calendar years derived from carbon-14 dating should not be considered an absolute truth as it is always an uncertainty involved, and the choice of age-depth model for dating a sequence should be based on scientific knowledge of the actual area.

No description available.

A testing framework was developed to address system spatial and temporal performance characteristics in a two-dimensional (2D) human motion analysis system using commercially available digital video capture. The first testing protocol involved developing a method to evaluate system spatial performance characteristics with respect to accuracy, precision, and resolution. A physical model comprising a calibration frame was constructed with phantom postures selected to represent joint angles and off-plane movement typical of the activities of interest. This provided reference angles to which angles measured from digitally captured images were compared using the Bland and Altman method. Validation experiments confirmed that the principal sources of error were due to off-plane motion and pixel resolution in the video capture and analysis systems. In these analyses, it was verified that simulated experimental conditions could be corrected using the direct linear transform (DLT); however, the removal of parallax still resulted in 2 degrees of error in measured joint angles. The main source of error was resolution of the data acquisition system verified through Monte Carlo simulations. The second testing protocol involved developing a simple method to determine the temporal accuracy of motion analysis systems incorporating digital video cameras and a pendulum. A planar column pendulum with a natural frequency of 0.872 Hz was used to analyse five systems incorporating commercially available cameras and a single codec. The frame rate for each camera was measured to be within 3% of the US National Television Systems Committee (NTSC) broadcasting digital video standard of 29.97 fps.; however some cameras produced a frame duplication artefact. Least squares curve-fitting using a sinusoidal function revealed RMS differences between 3-5% for angular position and 5-15% for angular speed compared to the captured motion data. It was shown that some digital-video cameras and computer playback software contain data compression technology that may produce substantial temporal frame inaccuracies in recovered video sequences and that temporal accuracy should be evaluated in digital-based human motion analysis systems prior to their use in experimentation. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2009-08-14 10:54:58.685

No description available.

L’athérosclérose est une maladie qui cause, par l’accumulation de plaques lipidiques, le durcissement de la paroi des artères et le rétrécissement de la lumière. Ces lésions sont généralement localisées sur les segments artériels coronariens, carotidiens, aortiques, rénaux, digestifs et périphériques. En ce qui concerne l’atteinte périphérique, celle des membres inférieurs est particulièrement fréquente. En effet, la sévérité de ces lésions artérielles est souvent évaluée par le degré d’une sténose (réduction >50 % du diamètre de la lumière) en angiographie, imagerie par résonnance magnétique (IRM), tomodensitométrie ou échographie. Cependant, pour planifier une intervention chirurgicale, une représentation géométrique artérielle 3D est notamment préférable. Les méthodes d’imagerie par coupe (IRM et tomodensitométrie) sont très performantes pour générer une imagerie tridimensionnelle de bonne qualité mais leurs utilisations sont dispendieuses et invasives pour les patients. L’échographie 3D peut constituer une avenue très prometteuse en imagerie pour la localisation et la quantification des sténoses. Cette modalité d’imagerie offre des avantages distincts tels la commodité, des coûts peu élevés pour un diagnostic non invasif (sans irradiation ni agent de contraste néphrotoxique) et aussi l’option d’analyse en Doppler pour quantifier le flux sanguin. Étant donné que les robots médicaux ont déjà été utilisés avec succès en chirurgie et en orthopédie, notre équipe a conçu un nouveau système robotique d’échographie 3D pour détecter et quantifier les sténoses des membres inférieurs. Avec cette nouvelle technologie, un radiologue fait l’apprentissage manuel au robot d’un balayage échographique du vaisseau concerné. Par la suite, le robot répète à très haute précision la trajectoire apprise, contrôle simultanément le processus d’acquisition d’images échographiques à un pas d’échantillonnage constant et conserve de façon sécuritaire la force appliquée par la sonde sur la peau du patient. Par conséquent, la reconstruction d’une géométrie artérielle 3D des membres inférieurs à partir de ce système pourrait permettre une localisation et une quantification des sténoses à très grande fiabilité. L’objectif de ce projet de recherche consistait donc à valider et optimiser ce système robotisé d’imagerie échographique 3D. La fiabilité d’une géométrie reconstruite en 3D à partir d’un système référentiel robotique dépend beaucoup de la précision du positionnement et de la procédure de calibration. De ce fait, la précision pour le positionnement du bras robotique fut évaluée à travers son espace de travail avec un fantôme spécialement conçu pour simuler la configuration des artères des membres inférieurs (article 1 - chapitre 3). De plus, un fantôme de fils croisés en forme de Z a été conçu pour assurer une calibration précise du système robotique (article 2 - chapitre 4). Ces méthodes optimales ont été utilisées pour valider le système pour l’application clinique et trouver la transformation qui convertit les coordonnées de l’image échographique 2D dans le référentiel cartésien du bras robotisé. À partir de ces résultats, tout objet balayé par le système robotique peut être caractérisé pour une reconstruction 3D adéquate. Des fantômes vasculaires compatibles avec plusieurs modalités d’imagerie ont été utilisés pour simuler différentes représentations artérielles des membres inférieurs (article 2 - chapitre 4, article 3 - chapitre 5). La validation des géométries reconstruites a été effectuée à l`aide d`analyses comparatives. La précision pour localiser et quantifier les sténoses avec ce système robotisé d’imagerie échographique 3D a aussi été déterminée. Ces évaluations ont été réalisées in vivo pour percevoir le potentiel de l’utilisation d’un tel système en clinique (article 3- chapitre 5). / Atherosclerosis is a disease caused by the accumulation of lipid deposits inducing the remodeling and hardening of the vessel wall, which leads to a progressive narrowing of arteries. These lesions are generally located on the coronary, carotid, aortic, renal, digestive and peripheral arteries. With regards to peripheral vessels, lower limb arteries are frequently affected. The severity of arterial lesions are evaluated by the stenosis degree (reduction > 50.0 % of the lumen diameter) using angiography, magnetic resonance angiography (MRA), computed tomography (CT) and ultrasound (US). However, to plan a surgical therapeutic intervention, a 3D arterial geometric representation is notably preferable. Imaging methods such as MRA and CT are very efficient to generate a three-dimensional imaging of good quality even though their use is expensive and invasive for patients. 3D-ultrasound can be perceived as a promising avenue in imaging for the location and the quantification of stenoses. This non invasive, non allergic (i.e, nephrotoxic contrast agent) and non-radioactive imaging modality offers distinct advantages in convenience, low cost and also multiple diagnostic options to quantify blood flow in Doppler. Since medical robots already have been used with success in surgery and orthopedics, our team has conceived a new medical 3D-US robotic imaging system to localize and quantify arterial stenoses in lower limb vessels. With this new technology, a clinician manually teaches the robotic arm the scanning path. Then, the robotic arm repeats with high precision the taught trajectory and controls simultaneously the ultrasound image acquisition process at even sampling and preserves safely the force applied by the US probe. Consequently, the reconstruction of a lower limb arterial geometry in 3D with this system could allow the location and quantification of stenoses with high accuracy. The objective of this research project consisted in validating and optimizing this 3D-ultrasound imaging robotic system. The reliability of a 3D reconstructed geometry obtained with 2D-US images captured with a robotic system depends considerably on the positioning accuracy and the calibration procedure. Thus, the positioning accuracy of the robotic arm was evaluated in the workspace with a lower limb-mimicking phantom design (article 1 - chapter 3). In addition, a Z-phantom was designed to assure a precise calibration of the robotic system. These optimal methods were used to validate the system for the clinical application and to find the transformation which converts image coordinates of a 2D-ultrasound image into the robotic arm referential. From these results, all objects scanned by the robotic system can be adequately reconstructed in 3D. Multimodal imaging vascular phantoms of lower limb arteries were used to evaluate the accuracy of the 3D representations (article 2 - chapter 4, article 3 - chapter 5). The validation of the reconstructed geometry with this system was performed by comparing surface points with the manufacturing vascular phantom file surface points. The accuracy to localize and quantify stenoses with the 3D-ultrasound robotic imaging system was also determined. These same evaluations were analyzed in vivo to perceive the feasibility of the study.