Дисертації з теми "Absorption estimation"
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1
Zhang, Changjun. "Seismic absorption estimation and compensation." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2820.
Повний текст джерелаАнотація:
As seismic waves travel through the earth, the visco-elasticity of the earth's medium will cause energy dissipation and waveform distortion. This phenomenon is referred to as seismic absorption or attenuation. The absorptive property of a medium can be described by a quality factor Q, which determines the energy decay and a velocity dispersion relationship.
Four new ideas have been developed in this thesis to deal with the estimation and application of seismic absorption. By assuming that the amplitude spectrum of a seismic wavelet may be modeled by that of a Ricker wavelet, an analytical relation has been derived to estimate a quality factor from the seismic data peak frequency variation with time. This relation plays a central role in quality factor estimation problems. To estimate interval Q for reservoir description, a method called reflectivity guided seismic attenuation analysis is proposed. This method first estimates peak frequencies at a common midpoint location, then correlates the peak frequency with sparsely-distributed reflectivities, and finally calculates Q values from the peak frequencies at the reflectivity locations. The peak frequency is estimated from the prestack CMP gather using peak frequency variation with offset analysis which is similar to amplitude variation with offset analysis in implementation. The estimated Q section has the same layer boundaries of the acoustic impedance or other layer properties. Therefore, the seismic attenuation property obtained with the guide of reflectivity is easy to interpret for the purpose of reservoir description. To overcome the instability problem of conventional inverse Q filtering, Q compensation is formulated as a least-squares (LS) inverse problem based on statistical theory. The matrix of forward modeling is composed of time-variant wavelets. The LS de-absorption is solved by an iterative non-parametric approach. To compensate for absorption in migrated seismic sections, a refocusing technique is developed using non-stationary multi-dimensional deconvolution. A numerical method is introduced to calculate the blurring function in layered media, and a least squares inverse scheme is used to remove the blurring effect in order to refocus the migrated image. This refocusing process can be used as an alternative to regular migration with absorption compensation.
2
Karlsson, Hanna, Ingemar Fredriksson, Marcus Larsson, and Tomas Strömberg. "Inverse Monte Carlo for estimation of scattering and absorption in liquid optical phantoms." Linköpings universitet, Biomedicinsk instrumentteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-78815.
Повний текст джерелаАнотація:
A spectroscopic probe with multiple detecting fibers was used for quantifying absorption and scattering in liquid optical phantoms. The phantoms were mixtures of Intralipid and red and blue food dyes. Intensity calibration for the detecting fibers was undertaken using either a microsphere suspension (absolute calibration) or a uniform detector illumination (relative calibration between detectors). Two different scattering phase functions were used in an inverse Monte Carlo algorithm. Data were evaluated for residual spectra (systematic deviations and magnitude) and accuracy in estimation of scattering and absorption. Spectral fitting was improved by allowing for a 10% intensity relaxation in the optimization algorithm. For a multi-detector setup, non-systematic residual spectrum was only found using the more complex Gegenbauer-kernel phase function. However, the choice of phase function did not influence the accuracy in the estimation of absorption and scattering. Similar estimation accuracy as in the multi-detector setup was also obtained using either two relative calibrated detectors or one absolute calibrated detector at a fiber separation of 0.46 mm.Funding Agencies|VINNOVA||Perimed AB|2008-00149|ResearchGrow program|2011-03074|European Union||Linkoping University through the Center for Excellence NIMED-CBDP (Center for Biomedical Data Processing)||
3
Layfield, Andrew. "An evaluation of selected estimation methods for the processing of differential absorption lidar data." Thesis, University of Hull, 1987. http://hydra.hull.ac.uk/resources/hull:16436.
Повний текст джерелаАнотація:
This work examines the application of selected estimation methods to path integrated direct detection CO2 lidar data, with the objective of improving the precision in the estimates of the log power, and log power ratios. Particular emphasis is given to the optimal estimation techniques of Kalman filtering theory, and to the consequent requirements for system and measurement model identification. A dual wavelength system was designed and constructed, employing two hybridised TEA lasers, a co-axial transceiver, and direct detection. Over a period of several months, a database of differential absorption measurements was accumulated, each consisting of 10,000 dual wavelength lidar returns. Various wavelength pairs were used, including those recommended for the monitoring of H2O, CO2, NH3 and C2H4. A subset of this database is used to evaluate the above mentioned estimation methods. The results are compared with simulated data files in which it was possible to control precisely process models which are believed to form an approximation to the real processes latent in the actual lidar data.
4
Fox-Neff, Kristen. "Inverse Methods in Parameter Estimation for High Intensity Focused Ultrasound (HIFU)." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1459155373.
Повний текст джерела
5
Martínez, Maradiaga David Estéfano. "Modelling and data validation for the energy analysis of absorption refrigeration systems." Doctoral thesis, Universitat Rovira i Virgili, 2013. http://hdl.handle.net/10803/128508.
Повний текст джерелаАнотація:
Data validation and reconciliation techniques have been extensively used in the process industry to improve the data accuracy. These techniques exploit the redundancy in the measurements in order to obtain a set of adjusted measurements that satisfy the plant model. Nevertheless, not many applications deal with closed cycles with complex connectivity and recycle loops, as in absorption refrigeration cycles. This thesis proposes a methodology for the steady-state data validation of absorption refrigeration systems. This methodology includes the identification of steady-state, resolution of the data reconciliation and parameter estimation problems and the detection and elimination of gross errors. The methodology developed through this thesis will be useful for generating a set of coherent measurements and operation parameters of an absorption chiller for downstream applications: performance calculation, development of empirical models, optimisation, etc. The methodology is demonstrated using experimental data of different types of absorption refrigeration systems with different levels of redundancy.Los procedimientos de validación y reconciliación de datos se han utilizado en la industria de procesos para mejorar la precisión de los datos. Estos procedimientos aprovechan la redundancia enlas mediciones para obtener un conjunto de datos ajustados que satisfacen el modelo de la planta. Sin embargo, no hay muchas aplicaciones que traten con ciclos cerrados, y configuraciones complejas, como los ciclos de refrigeración por absorción. Esta tesis propone una metodología para la validación de datos en estado estacionario de enfriadoras de absorción. Estametodología incluye la identificación del estado estacionario, la resolución de los problemas de reconciliación de datos y estimación de parámetrosy la detección de errores sistemáticos. Esta metodología será útil para generar un conjunto de medidas coherentes para aplicaciones como: cálculo de prestaciones, desarrollo de modelos empíricos, optimización, etc. La metodología es demostrada utilizando datos experimentales de diferentes enfriadoras de absorción, con diferentes niveles de redundancia.
6
Johansson, Johannes, and Karin Wårdell. "Intracerebral quantitative chromophore estimation from reflectance spectra captured during deep brain stimulation implantation." Linköpings universitet, Biomedicinsk instrumentteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-81381.
Повний текст джерелаАнотація:
Quantification of blood fraction (fblood), blood oxygenation (S
), melanin, lipofuscin and oxidised and reduced Cytochrome aa 3 and c was done from diffuse reflectance spectra captured in cortex, white matter, globus pallidus internus (GPi) and subthalamus during stereotactic implantations of 29 deep brain stimulation (DBS) electrodes with the aim of investigating whether the chromophores can give physiological information about the targets for DBS. Double-sided Mann-Whitney U -tests showed more lipofuscin in GPi compared to white matter and subthalamus (p < 0.05). Compared to the other structures, fbloodwas significantly higher in cortex (p < 0.05) and S
lower in GPi (p < 0.05). Median values and range for fblood were 1.0 [0.2–6.0]% in the cortex, 0.3 [0.1–8.2]% in white matter, 0.2 [0.1–0.8]% in the GPi and 0.2 [0.1–11.7]% in the subthalamus. Corresponding values for S
was 20 [0–81]% in the cortex, 29 [0–78]% in white matter, 0 [0–0]% in the GPi and 0 [0–92]% in the subthalamus. In conclusion, the measurements indicate very low oxygenation and blood volume for DBS patients, especially in the GPi. It would be of great interest to investigate whether this is due to the disease, the normal situation or an artefact of doing invasive measurements.
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Braddy, April C. "Increased-throughput screening of potential drug candidates for permeation across membranes and estimation of central nervous system bioavailability." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0008420.
Повний текст джерелаАнотація:
Thesis (Ph.D.)--University of Florida, 2004.Typescript. Title from title page of source document. Document formatted into pages; contains 167 pages. Includes Vita. Includes bibliographical references.
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Zhang, Yunjiang. "Estimation multi-annuelle des sources d’aérosols organiques et de leurs propriétés d’absorption de la lumière en région Parisienne." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLV013.
Повний текст джерелаАнотація:
Les aérosols carbonés, qui incluent les aérosols organiques (AO) et le carbone suie (BC), jouent un rôle majeur sur la qualité de l’air et sur le climat. Il est donc primordial de pouvoir quantifier leurs sources, ainsi que celles de leurs précurseurs gazeux, pour la mise en œuvre de plans d’action appropriés. Les études de tendance sur la composition chimique de l’atmosphère sont également nécessaires afin d’améliorer les connaissances de l’impact des particules sur le réchauffement climatique, actuel et à venir. Ce travail de thèse a permis d’exploiter les mesures automatiques et in situ des aérosols carbonés réalisées au SIRTA (Site de Recherche par Télédétection Atmosphérique) depuis plus de 6 ans. Cet observatoire appartient au programme européen ACTRIS (infrastructure de recherche européenne sur les aérosols, nuages, et espèces gazeuses réactives). Il est situé à 25 km au sud-ouest de Paris et est représentatif de la pollution de fond en région Ile de France. Les principales sources d’AO ont été discriminées à l’aide de l’outil Positive Matrix Factorization appliqué aux données issus d’un Aerosol Chemical Speciation Monitor (ACSM). Les propriétés d’absorption de la lumière de BC et du brown carbon (BrC) ont été mesurées à l’aide d’un aethalomètre multi-longueurs d’onde. L’ensemble des résultats obtenus indiquent des cycles saisonniers, hebdomadaires et journaliers spécifiques aux différentes fractions des aérosols primaires et secondaires. Ils ont confirmé que l’AO primaire (AOP), provenant essentiellement de la combustion de biomasse et du transport routier, est prépondérant sur la période froide (de novembre à février), alors que le reste de l’année est dominé par des aérosols organiques oxygénés. Parmi ces derniers, une fraction moins oxydée, provenant probablement de façon majeure de précurseurs biogéniques, est prépondérante en été (60% de l’AO en moyenne estivale). Les études de tendance ont montré une légère diminution des concentrations (de l’ordre de 0.05-0.20 µg/m3 par an) de toutes les fractions d’AO identifiées au cours de la période étudiée, hormis pour cette fraction d’AO moins oxydée qui ne présente pas de tendance significative. Concernant les propriétés optiques, une contribution moyenne globalement équivalente à celle de BC a été observée pour le BrC dans le proche ultraviolet en hiver. Par ailleurs, il a été mis en évidence une augmentation significative des propriétés d’absorption du BC liée à des interactions avec les aérosols secondaires en mélange interne, en particulier en été (avec une valeur moyenne de 1.6 pour le paramètre Eabs). La fraction organique la plus oxydée a pu être identifiée comme principale responsable de ce phénomène, faisant des aérosols organiques secondaires l’une des fractions des particules les plus importants à considérer par les modèles climatiquesCarbonaceous aerosols, including organic aerosols (OA) and black carbon (BC), are playing important roles on air quality and climate change. Therefore, quantifying contribution of their emission sources, as well as the sources of their gaseous precursors, is needed to implement efficient mitigation measures. Investigating trends in atmospheric composition is also essential to a better knowledge of present and future impacts of airborne particles on global warming. This work aimed at investigating on-line and in situ carbonaceous aerosol measurements performed for more than 6 years at the SIRTA facility (Site Instrumental de Recherche par Télédétection Atmosphérique). This observatory platform is part of the ACTRIS (Aerosols, Clouds, Trace gases Research InfraStructure). It is located 25 km southwest of Paris city center and is representative of background air quality in the Ile de France region. The main sources of submicron OA were discriminated through Positive Matrix Factorization applied to Aerosol Chemical Speciation Monitor (ACSM) data. Light absorption properties of BC and brown carbon (BrC) were obtained from multi-wavelength Aethalometer measurements. Converging results illustrated well-marked seasonal, weekly, and diel cycles of the various primary and secondary carbonaceous aerosol fractions. Primary OA (POA), mainly from wood burning and traffic emissions, were confirmed to dominate submicron OA concentrations during the coldest months (November to February), while Oxygenated OA (OOA) were shown as the major contributors during the rest of the year. Less Oxidized OOA (LO-OOA), possibly with predominant biogenic origins, were found to contribute up to about 60% of total submicron OA on average in summer. Trend analyses indicated slight decreasing features (in the range of 0.05-0.20 µg m-3 yr-1) for every OA fractions over the 6+-year investigated period, except for this LO-OOA factor which showed no significant trend. Regarding absorption properties, BrC - with overwhelming biomass burning origin - was found to have equivalent light absorption impact than BC at near-ultraviolet wavelengths during the winter season. In summer, a mean value of 1.6 was obtained for BC absorption enhancement (Eabs) due to secondary aerosol lensing effect, supporting possible higher BC-related radiative impact than currently expected. Last but not least, More Oxidized OOA (MO-OOA) were shown as the main agent for this Eabs and then appeared as one of the most critical aerosol fraction to be considered within near-future climate models
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Hay, Timothy Deane. "MAX-DOAS measurements of bromine explosion events in McMurdo Sound, Antarctica." Thesis, University of Canterbury. Physics and Astronomy, 2010. http://hdl.handle.net/10092/5394.
Повний текст джерелаАнотація:
Reactive halogen species (RHS) are responsible for ozone depletion and oxidation of gaseous elemental mercury and dimethyl sulphide in the polar boundary layer, but the sources and mechanisms controlling their catalytic reaction cycles are still not completely understood. To further investigate these processes, ground– based Multi–Axis Differential Optical Absorption Spectroscopy (MAX-DOAS)
observations of boundary layer BrO and IO were made from a portable instrument platform in McMurdo Sound during the Antarctic spring of 2006 and 2007. Measurements of surface ozone, temperature, pressure, humidity, and wind speed and direction were also made, along with fourteen tethersonde soundings and the collection of snow samples for mercury analysis.
A spherical multiple scattering Monte Carlo radiative transfer model (RTM) was developed for the simulation of box-air-mass-factors (box-AMFs), which are used to determine the weighting functions and forward model differential slant column densities (DSCDs) required for optimal estimation. The RTM employed the backward adjoint simulation technique for the fast calculation of box-AMFs
for specific solar zenith angles (SZA) and MAX-DOAS measurement geometries. Rayleigh and Henyey-Greenstein scattering, ground topography and reflection, refraction, and molecular absorption by multiple species were included. Radiance and box-AMF simulations for MAX-DOAS measurements were compared with nine other RTMs and showed good agreement.
A maximum a posteriori (MAP) optimal estimation algorithm was developed to retrieve trace gas concentration profiles from the DSCDs derived from the DOAS analysis of the measured absorption spectra. The retrieval algorithm was validated by performing an inversion of artificial DSCDs, simulated from known NO2 profiles. Profiles with a maximum concentration near the ground were generally well reproduced, but the retrieval of elevated layers was less accurate. Retrieved partial vertical column densities (VCDs) were similar to the known values, and investigation of the averaging kernels indicated that these were the most reliable retrieval product. NO₂ profiles were also retrieved from measurements made at an NO₂ measurement and profiling intercomparison campaign in Cabauw, Netherlands in July 2009.
Boundary layer BrO was observed on several days throughout both measurement periods in McMurdo Sound, with a maximum retrieved surface mixing ratio of 14.4±0.3 ppt. The median partial VCDs up to 3km were 9.7±0.07 x 10¹² molec cm ⁻ in 2007, with a maximum of 2.3±0.07 x 10¹³ molec cm⁻², and 7.4±0.06 x 10¹² molec cm⁻² in 2006, with a maximum of 1.05 ± 0.07 x 1013 molec cm⁻². The median mixing ratio of 7.5±0.5 ppt for 2007 was significantly higher than
the median of 5.2±0.5 ppt observed in 2006, which may be related to the more extensive first year sea ice in 2007. These values are consistent with, though lower than estimated boundary layer BrO concentrations at other polar coastal sites. Four out of five observed partial ozone depletion events (ODEs) occurred during strong winds and blowing snow, while BrO was present in the boundary layer in
both stormy and calm conditions, consistent with the activation of RHS in these two weather extremes. Air mass back trajectories, modelled using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, indicated that the events were locally produced rather than transported from other sea ice zones. Boundary layer IO mixing ratios of 0.5–2.5±0.2 ppt were observed on several days. These values are low compared to measurements at Halley and Neumayer Stations, as well as mid-latitudes. Significantly higher total mercury concentrations observed in 2007 may be related to the higher boundary layer BrO
concentrations, but further measurements are required to verify this.
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Morettini, Micaela. "Mathematical model of standard oral glucose tolerance test for characterization of insulin potentiation in health." Doctoral thesis, Università Politecnica delle Marche, 2012. http://hdl.handle.net/11566/241987.
Повний текст джерелаАнотація:
In questo lavoro di tesi vengono proposte due diverse formulazioni (INT_M1 e INT_M2) di un nuovo modello integrato per la descrizione delle risposte del sistema di regolazione glucosio-insulina alla somministrazione orale di glucosio (oral glucose tolerance test, OGTT).
INT_M1 e INT_M2 si differenziano per la descrizione dell’assorbimento gastrointestinale adottata: un modello ad un compartimento ed una funzione empirica per il primo ed un modello a tre compartimenti non lineare per il secondo.
L’implementazione del modello in ambiente Matlab, all’interno di una nuova procedura di stima parametrica a due passi, ha permesso l’ottimizzazione di parametri caratteristici dell’assorbimento gastro-intestinale e della cinetica del glucosio, dell’insulina e dell’incretina. Il comportamento del modello è stato testato mediante best-fit di dati medi, presi dalla letteratura, delle concentrazioni plasmatiche di glucosio, insulina, di GIP (glucose-dependent insulinotropic polipeptide) e GLP-1 (glucagon-like peptide 1) misurati in due gruppi di soggetti sani (HC-1 e HC-2) sottoposti ad un protocollo OGTT standard e, successivamente, ad un protocollo endovenoso caratterizzato dalla somministrazione di un eguale andamento temporale del glucosio (isoglycemic intravenous glucose, I-IVG, infusion). I due modelli sono stati confrontati per quanto riguarda la capacità di riprodurre il potenziamento dell’insulina indotto dall’incretina ovvero l’aumentata risposta insulinica che si osserva a seguito di un OGTT paragonata a quella dell’I-IVG.
Nell’ipotesi di un’azione additiva del GIP e del GLP-1 sul potenziamento dell’insulina, i risultati hanno mostrato una sostanziale equivalenza dei due modelli nel riprodurre i dati. Inoltre, i parametri stimati sembrano essere buoni indicatori delle differenze osservate nei due gruppi di soggetti sani. Infine la procedura di stima messa a punto apre la strada a future applicazioni mirate all’individualizzazione dell’effetto incretina.Two new formulations, respectively denominated INT_M1 and INT_M2, of an integrated mathematical model to describe the glycemic and insulinemic responses to a 75 g oral glucose tolerance test (OGTT) are proposed and compared. The INT_M1 assumes a single compartment for the intestine and the derivative of a power exponential function for monophasic representation of gastric emptying rate profile. In the INT_M2, a nonlinear three-compartment system model is adopted to produce a more realistic, multiphase gastric emptying rate. Both models were implemented in a Matlab-based, two-step procedure for estimation of seven adjustable coefficients characterizing the gastric emptying rate and the incretin, insulin and glucose kinetics. Model behaviour was tested vs. data of mean plasma glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), glucose and insulin concentrations provided by two different laboratories, where glycemic profiles observed during a 75 g OGTT were matched in healthy subjects (HC1- and HC2-group, respectively) by means of an isoglycemic intravenous glucose (I-IVG) infusion. Under the hypothesis of an additive effect of GLP-1 and GIP on insulin potentiation, our results demonstrated a substantial equivalence of the two models in matching the data. Model parameter estimates showed to be suitable markers of differences observed in the OGTT and matched I-IVG responses from the HC1-group compared to the HC2-group. Model implementation in our two-step parameter estimation procedure enhances the possibility of a prospective application for individualization of the incretin effect in a single subject, when his/her data are plugged in.
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O'Neill, Brendan Commander(Brendan William). "Signal absorption-based range estimator for undersea swarms." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/129031.
Повний текст джерелаАнотація:
Thesis: S.M., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Mechanical Engineering; and the Woods Hole Oceanographic Institution), September, 2020Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 97-102).
Robotic swarms are becoming increasingly complex on the surface and in air due to highspeed and reliable communication links, Global Positioning Satellites (GPS), and visual support to relative navigation. However, the limited propagation of these signals in the ocean has impacted similar advances in undersea robotics. Autonomous underwater vehicles (AUVs) often rely on acoustics to inform navigation solutions; however, this approach presents challenges for scalable robotic swarms. Acoustic navigation is a means to inform range and bearing to a target. Many methods for range and bearing estimation, including current low-cost solutions, rely on precision time synchronization or two-way communication to compute ranges as part of a full navigation solution. The high cost of reliable Chip-scale atomic clocks (CSACs) and acoustic modems relative to other vehicle components limits large-scale swarms due to the associated cost-per-vehicle and communications infrastructure.
We propose a single, high-cost vehicle with a reliable navigation solution as a "leader" for a scalable swarm of lower-cost vehicles that receive acoustic signals from a source onboard the lead vehicle using a single hydrophone. These lower-cost "followers" navigate relative to the leader according to the preferred behavioral pattern, but for simplicity, we will refer to a simple following behavior in this work. This thesis outlines a method to obtain range estimates to sound sources in which the signal content, including frequency and power at its origin, can be reasonably approximated. Total transmission loss is calculated based on empirical equations for the absorption of sound in seawater and combined with geometric spreading loss from environmental models to estimate range to a source based on the loss at differential frequencies. We refer to this calculation as the signal absorption-based range estimator (SABRE).
This method for obtaining range combines with Doppler-shift methods for target bearing based on the maximum frequency detected within a banded limit around a known source frequency. A primary objective for SABRE is to address techniques that support low-cost options for undersea swarming. This thesis's contributions include a novel method for range estimation onboard underwater autonomous vehicles that supports navigation relative to a known source when combined with Doppler-shift methods for target bearing. This thesis seeks to develop the theory, algorithms, and analytical tools required and apply those tools to real-world data sets to investigate the feasibility, sources of error, and accuracy of this new approach to range estimation for underwater swarms.
by Brendan O'Neill.
S.M.
S.M. Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Mechanical Engineering; and the Woods Hole Oceanographic Institution)
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Jawad, Ourouk. "Etude de l'exposition des personnes aux ondes électromagnétiques en environnement complexe." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066292/document.
Повний текст джерелаАнотація:
Les recherches en dosimétrie numérique non-ionisante ont connu des avancées considérables notamment grâce à la capacité de calcul croissante des ordinateurs. Ces dernières années, la prise en compte de la variabilité dans la dosimétrie est devenue un enjeu majeur. Les sources de variabilité sont nombreuses, parmi elles, les conditions d'exposition au rayonnement électromagnétique peuvent induire des doses absorbées très différentes. La modélisation de canal de propagation en environnement intérieur a permis d'avoir une connaissance précise des conditions d'exposition d'un corps humain plongé dans cet environnement. Cette thèse a pour but de développer une méthode statistique du calcul de la dose absorbée par le corps et d'adapter le modèle de canal stochastique à la dosimétrie. L'étude statistique de l'exposition a révélé la nécessité d'obtenir les valeurs de Débit d'Absorption Spécifique corps entier dans le cas d'expositions à une onde plane pour tous les angles d'incidence possibles. Compte tenu des temps de calcul particulièrement long en dosimétrie, une méthode d'interpolation efficace, le krigeage, des valeurs de Débit d'Absorption Spécifique a été mise en oeuvre. L'analyse de sensibilité aux paramètres du canal des moments du Débit d'Absorption Spécifique a permis de connaître l'impact de chacun de ces paramètres. Le modèle de canal a pu être simplifié et donc adapté à la dosimétrie tout en quantifiant l'erreur d'approximation qu'implique cette simplification. Cette thèse répond à l'enjeu de la prise en compte de la variabilité en dosimétrie dans un environnement complexeResearch in non-ionizing numerical dosimetry has been improved thanks to high calculation capacity of computers. These years, integrating variability in the field of dosimetry has become a major issue. Sources of variability are numerous; among them, there are the exposure conditions to electromagnetic radiation which can lead to very different absorbed doses. Indoor channel modeling enables to have a deep knowledge of the exposure conditions of a human body located inside this indoor environment. The aim of this thesis is to develop a statistical method of calculation of the absorbed dose by the human body and to adapt the stochastic channel model to dosimetry. The statistical study of exposure reveals the need to obtain Specific Absorption Rate values for a plane wave exposure for all possible angles of incidence. Taking into account that computation in dosimetry is time consuming, an efficient interpolation method, kriging method, is implemented in order to get whole body Specific Absorption Rate values. Kriging method enables to obtain Specific Absorption Rate for all possible angles of incidence and then to calculate expectation and variance of Specific Absorption Rate. Sensitivity Analysis of expectation and variance to the statistical channel parameters reveals the impact of each parameter. The channel model has been simplified and then adapted to dosimetry by estimating the approximation error induced by this reduction. This thesis answers to the issue of integrating variability in dosimetry in a complex environment and develop the tools that open a new path in studying exposure in any complex environment
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Ovigneur, Bertrand. "Description des propriétés macrophysiques et microphysiques des nuages par télédétection active et passive : application à la campagne aéroportée FRENCH/DIRAC." Lille 1, 2005. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2005/50376-2005-Ovigneur.pdf.
Повний текст джерелаАнотація:
Les nuages sont l'une des principales sources d'incertitudes de la prévision du climat futur de la Terre. L'étude présentée vise à développer des méthodes affinant la description tant macrophysique que microphysique des nuages à partir de mesures aéroportées. Ces méthodes peuvent être à terme appliquées à des mesures spatiales du type de celles du train de l'espace, l'A -train. A cet effet, les mesures de deux radiomètres (POLDER et MiniMIR) et d'un lidar (LEANDRE) acquises pendant la campagne aéroportée FRENCH/DIRAC sont exploitées. Une méthode d'absorption différentielle est développée et utilisée pour corriger les mesures des deux radiomètres POLDER et MiniMIR de l'absorption par les gaz atmosphériques. POLDER, avec son large champ de vue, effectue une mesure radiométrique multidirectionnelle. La luminance multidirectionnelle d'une scène nuageuse est obtenue en la suivant sur plusieurs acquisitions successives de l'instrument. POLDER et LEANDRE permettent une évaluation de l'altitude des nuages. Le lidar fournit l'information la plus précise et peut permettre de discriminer les sommets et les bases de plusieurs couches nuageusesPar des méthodes stéréoscopiques ou basées sur l'absorption par le dioxygène, POLDER fournit une information sur l'altitude des nuages. Celle-ci est moins précise mais présente l'avantage de rendre compte du large champ spatial couvert par l'instrument. Les mesures polarisées de POLDER ou de LEANDRE permettent une estimation de la phase thermodynamique des nuages, mais par commodité, une méthode simple basée sur le rapport des luminances mesurées dans le visible et le moyen infrarouge par MiniMIR est développée et privilégiée dans cette étude. Finalement, une méthode d'estimation optimale est développée et mise en œuvre pour déterminer l'épaisseur optique des nuages et la dimension des particules qui les constituent à partir de mesures passives dans le visible et dans le moyen infrarouge. Comparée aux méthodes précédemment développées au laboratoire, cette méthode permet d'obtenir des précisions similaires sur les paramètres nuageux déterminés. Toutefois, elle offre l'avantage d'exploiter naturellement les mesures multidirectionnelles de POLDER ainsi que d'autres informations ou données auxiliaires. De part sa modularité, cette méthode pourrait permettre d'exploiter en synergie les mesures de l'A-train
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Gorman, Ng Melanie. "Development of a predictive tool for estimating occupational inadvertent ingestion exposure." Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=211182.
Повний текст джерелаАнотація:
There are three primary routes by which occupational exposure to hazardous substances occurs: inhalation, dermal absorption, and ingestion. Of these, ingestion has been the least studied. Ingestion exposure is typically controlled in workplaces by the provision of clean eating areas that are separated from the work areas, and by encouraging hand-washing prior to eating. However, this control strategy does not affect ingestion exposure that can occur when contaminated hands or objects contact the mouth; these sorts of exposures can occur during work tasks in the general work area. For example, these sorts of contacts can occur when workers wipe their mouths or noses, chew pens or glasses, or bite their nails. Exposure by this pathway is called inadvertent ingestion exposure. In addition to the insertion of contaminated hands and objects directly into the oral cavity, contact can occur with the perioral area (the area surrounding the mouth) and transferred substances can subsequently transfer to the mouth. The aim of this thesis was to study inadvertent ingestion exposure in order to develop a generic predictive screening model to allow occupational hygienists and risk assessors to estimate exposure by inadvertent ingestion for a range of exposure scenarios. The thesis project was carried out in a series of steps, all of which are described below. The steps were carried out in the order presented and the findings from the work on earlier steps influenced the work carried out in later steps.
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Wetter, Erik. "Patterns of performance in new firms : estimating the effects of absorptive capacity." Doctoral thesis, Stockholm : Economic Research Institute, Stockholm School of Economics (EFI), 2009. http://www2.hhs.se/efi/summary/783.htm.
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Mukherjee, Moumita. "Instrumented permeable blankets for estimating subsurface hydraulic conductivity and confirming numerical models used for subsurface liquid injection." Diss., Connect to online resource - MSU authorized users, 2008.
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Träber, Stephan Christian [Verfasser], and Werner [Akademischer Betreuer] Rühm. "Estimating the absorption of ingested soil-derived uranium and the resulting internal dose to humans : development and application of a new method / Stephan Christian Träber ; Betreuer: Werner Rühm." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2021. http://d-nb.info/1236502175/34.
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AVEGLIANO, ROSEANE P. "Estudo de dieta total no estado de Sao Paulo: estimativa de ingestao dietetica de elementos toxicos (arsenico e cadmio) e essenciais (calcio, cromo, ferro, selenio, sodio, potassio e zinco)." reponame:Repositório Institucional do IPEN, 2009. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11523.
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Made available in DSpace on 2014-10-09T12:52:50Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:02:47Z (GMT). No. of bitstreams: 0
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Liao, Shaojuan. "Three Essays on Economic Growth and Technology Development: Considering the Spillover Effects." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/37808.
Повний текст джерелаАнотація:
This dissertation consists of three essays on the empirical analysis of economic growth and technology development. In particular, I
consider spillover effects in different frameworks. The first chapter outlines the three topics involved and briefly discusses the
motivations, methods as well as some conclusions in each of the following chapters.
The second chapter considers the spillovers in economic growth and convergence. Spillovers are prevalent in nowadays' economy. I formally model the spillover effects as the interdependence of total factor productivity (TFP), and develop a model in which spillover effects of R&D through the channel of international trade make the
TFPs correlated among countries. In this sense, I apply the thoughts of international trade to the economic growth framework. Empirically, I develop a three-stage generalized method of moment(GMM) to estimate the dynamic panel spatial error autoregressive model. Simulation results show that my estimator is consistent and efficient. Through counterfactual analysis, I find that there are positive spillovers through both geographic connection and trade connection. Such a positive spillover effect, however, slows down
the convergence speed. Moreover, there were little spillovers in the early 1960s. Spillover effects become stronger overtime.
The third chapter is about the determinants of technology development in China. What makes my paper different from others is that I take a full consideration of the spillover effects: provincial spillovers in Science and Technology (S&T) capital as well as S&T personnel, and international spillovers through trade and FDI. The most interesting point in my paper is that I consider the indirect effects of institutions on technology development. Marketization, measured by the share of state-owned enterprises (SOEs) in the economy, affects the production of technology through different channels at different stages. I use a semiparametric varying-coefficient model to account for the effects. In this paper, I find that provincial spillovers are mainly through the
externalities of S&T capital stock while international spillovers occur through trade. Marketization affects the technology development through S&T capital, S&T capital spillovers and trade. Although a certain share of SOEs is necessary for technology production, the marketization process will promote the development
of technology in China in the long run.
The fourth chapter looks into the provincial technology spillovers from another aspect. Instead of the S&T endowment spillovers from
the nearby provinces, I consider the technology transfer from the frontier province to the targeted province as well as the absorptive
capacity of the targeted province itself. Two forms of technology transfer are analyzed: the technology distance due to the structural
discrepancy in the patent portfolio and the technology gap because of the difference in the patent level. Through the empirical analysis, several factors contributing to patent growth, such as S&T investment, road density, international spillovers from imports and FDI, are identified. Moreover, I find that technology transfer due to the technology distance can stimulate patent growth. However, I fail to find robust evidence of technology transfer due to the
technology gap, which implies that the provincial technology convergence may not exist in China.Ph. D.
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王, 勝強, and Shengqiang WANG. "Remote Estimation of Phytoplankton Size Structure Using Light Absorption Spectra." Thesis, 2014. http://hdl.handle.net/2237/20720.
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LIN, YUAN-HUNG, and 林元弘. "Optimization of Specific Absorption Rate Based on a Fast Estimation Model for Multiple-Antenna Transmitters." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/g2v8u7.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
電子工程系
107
We use a rapid estimating model to calculate specific absorption rate (SAR) proposed by preceding studies to expand into optimized models. The SAR value is an important parameter for mobile handheld communication devices. We direct the primary beam of an antenna array toward the desired direction and minimize the maximum SAR value on an observation plane of a phantom simultaneously. In multi-antenna devices, the SAR value is affected by current amplitude distribution and excitation phases of feed currents. Mobile antennas designers will need to align the main beam of the multi-antenna while it is aiming at a target, as well as attempt to minimize the SAR value. However, it is very time-consuming to analyze the specific current amplitude distribution and phase angle caused by the SAR value through full-wave simulations. To reduce the number of simulations, Le’s research team proposed a fast estimation model to calculate the SAR value of multi-antenna transmitting devices. The key feature of this fast estimation model is that solely the pre-planned simulations for the array need to be managed and the current phase angles should satisfy the requirements of a specific matrix. Then, after calculating the SAR value caused by any phase angle, there is no need to re-analyze the phase angle through full-wave simulations, and we only need to follow the results of the array simulation to obtain a fast and accurate response. However, the rapid estimation simulation of the reference did not consider the calculation of different current amplitudes, and only the SAR value for a uniform current distribution can be obtained. Here, we expand the valid range of the cited method, allowing the model applied to the specific absorption rate values of arbitrary current amplitudes and excitation phases, and the model still demonstrates fast estimation. We used the full-wave simulation to verify the proposed method and the simulation results are in agreement with the numerical analysis. This indicates that this model uses the maximum SAR value of the surface as an objective function and uses the current amplitudes of multiple antennas as the decision variables. We use the enumeration method to solve the current distribution that minimizes the specific absorption rate. The four-antenna elements array was validated such that the primary beam of the antenna array is angled at 0˚, ±10˚, ±20˚… ±80˚, ±90˚, respectively, to minimize the maximum SAR value of these situations. The optimization results demonstrate that the method exhibits an average improvement of 19%. Finally, this thesis implements this four-antenna element array, which verified the accuracy of the method by measuring its radiation pattern.
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Chou, Hung-Yi, and 周宏奕. "In vitro estimation of percutaneous absorption of single or mixed exposure to Benzo(a)Pyrene and Di-hydroxybenzene." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/53751682720759327498.
Повний текст джерелаАнотація:
碩士中國醫藥大學
公共衛生學系碩士班
100
Benzene(a)pyrene is a kind of polycyclic aromatic hydrocarbons compounds, and it’s the group 1 carcinogen chemical classification of international cancer research organization, and many animals studies have confirm the carcinogenic potential for squamous cell carcinoma. Benzo(a)Pyrene is produced from combustion reaction, with other chemicals before the human exposure. In the past studies, benzo(a)Pyrene was only concerned about single exposure experiment, but co-exposed with other chemicals. The other kind of combustion reaction chemical, di-hydroxybenzene, has been shown to increase the possibility of skin cancer with benzo(a)pyrene. In this study we try to estimate of percutaneous absorption of single or mixed exposure to benzo(a)Pyrene and di-hydroxybenzene to calculate the kinetic parameters of skin penetration, and to discuss the possible health risks after skin exposure to benzo(a)pyrene and di-hydroxybenzene. In vitro static diffusion cell with a pig’s skin was used in our absorption experiment. Sequence tape-stripping method was used to estimate the substance distribution in stratum corneum. Then receptor fluid analysis was to know how many substances penetrate through the skin. Using the high-performance liquid chromatography with UV detector to analysis all of the samples, and used the results to estimate the kinetic parameters. The results showed the combined exposure to benzo(a)pyrene and di-hydroxybenzene would increase the amount of benzo(a)Pyrene in stratum corneum, and the diffusion coefficient and partition coefficient were also changed; for di-hydroxybenzene, the permeability coefficient of chemical substances was increased. The cancer risk increased when benzo(a)Pyrene and di-hydroxybenzene concurrent in occupational workers. In conclusions, co-exposure to benzo(a)Pyrene and di-hydroxybenzene will change the kinetic parameters in stratum corneum and the systemic absorption conditions, and it will increase the cancer risk from 1.49×10-4 to 5.55×10-4, when co-exposure to these chemical substances.
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OH, DOO-MAN. "ESTIMATING ORAL DRUG ABSORPTION IN HUMANS (DRUG ABSORPTION)." 1991. http://catalog.hathitrust.org/api/volumes/oclc/68790723.html.
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Crison, John Robert. "Estimating the dissolution and absorption of water insoluble drugs in the small intestine." 1993. http://catalog.hathitrust.org/api/volumes/oclc/68796629.html.
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Chen, Kuo-Feng, and 陳國峰. "Calculation of the Gain and Absorption Coefficient in Quantum We- ll and Estimating the Efficiency for Reducing Carriers Current by Multiple Quantum Barriers in Semiconductor Lasers." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/86514418157652798602.
Повний текст джерелаАнотація:
碩士國立交通大學
光電(科學)研究所
83
First, the optical gain and absorption without Coulomb interacti- on between electrons and holes are analyzed for quantum well las- ers. When the intraband relaxation is considered, the gain/absor- ption spectral shape becomes smooth and broad in spite of the sh- arp step-like density of state. However, the Coulomb attraction between the conduction-band electron and the valence-band hole l- eads to considerable changes in the optical properties of the qu- antum well around the absorption edge, especially below absorpti- on edge. There are intense absorption lines below the bandgap en- ergy, that is, less photon energy is required for the exciton tr- ansition compared with the bandgap transition. Finally, we have provided a clear and simple method for the optimal design of any MQB structure by calculating the carrier blocking efficiency for the first time. Our method predicted substantial improvement of the differential quantum efficiency of a SCH-SQW laser with opti- mal MQB design and agrees with experimental results.