No Brasil, atualmente só há um laboratório de calibração de monitores de radiação de nêutrons, sendo responsável pela guarda e manutenção do padrão brasileiro da fluência de nêutrons, localizado no Laboratório Nacional de Metrologia das Radiações Ionizantes (LNMRI), Rio de Janeiro, no Instituto de Radioproteção e Dosimetria, Comissão Nacional de Energia Nuclear, Rio de Janeiro, com uma demanda grande de serviços com esse tipo de radiação. Com o intuito de descentralizar a oferta de serviços de calibração, surgiu a necessidade da montagem de um segundo Laboratório de Calibração com Nêutrons (LCN), no IPEN. Nas situações práticas envolvendo a calibração de monitores de radiação de nêutrons, um dos problemas principais está relacionado à radiação espalhada, que pode variar dependendo das dimensões do laboratório usado nos procedimentos de calibração. No processo de caracterização do campo de radiação de nêutrons da fonte de 241AmBe, onde foi realizada a avaliação dos espectros, das energias, das taxas de fluência, das taxas de equivalente de dose ambiente [H*(10)] e do coeficiente de conversão de fluência em dose [h*φ(10)] em diferentes posições do LCN, utilizando o feixe completo. A influência da radiação espalhada foi determinada por meio de três técnicas: Métodos de Monte Carlo, de Ajuste Reduzido e do Cone de Sombra. Dos resultados obtidos por meio de simulação e experimentalmente foi possível obter a fração de espalhamento em diferentes distâncias fonte-detector. / In Brazil, there is currently only one calibration laboratory for neutron radiation monitors. It is responsible for the custody and maintenance of the Brazilian neutron fluence standard, located at the Laboratório Nacional de Metrologia das Radiações Ionizantes-LNMRI, Rio de Janeiro, at the Instituto de Radioproteção e Dosimetria, Comissão Nacional de Energia Nuclear, with a great demand of services with this type of radiation. In order to decentralize the calibration service offer, it was necessary to set up a second Neutron Calibration Laboratory (LCN), at IPEN. In practical situations involving the calibration of neutron radiation monitors, one of the main problems is related to scattered radiation, which may vary depending on the size of the laboratory used for the calibration procedures. In the process of characterization of the neutron radiation field of the 241AmBe source, the spectra, the energies, the fluence rate, the ambient dose equivalent rate and the conversion coefficient of fluence in dose at different positions of the LCN, were evaluated using the complete beam. The influence of the scattered radiation was determined by three techniques: Monte Carlo Method, the Reduced Adjustment Method and the Shade Cone Method. From the results obtained through simulation and experimentally, it was possible to obtain the scattering fraction at different source-detector distances.

The global retail business is extremely dynamic and this brings new issues in front of us and deserves responsibilities to address those issues. The Textile Retail Business is also experiencing this change as the whole retail textile supply chain has already become globalized with the time especially in terms of sourcing of raw materials and production as well. This phenomenon has raised the questions of threats regarding sustainability and resiliency of the supply chain. Today‘s retailers are working closely with these topics in a competition basis to achieve competitive advantages in their supply chain. This dissertation aims to sketch out the possible latent challenges for which the companies prefer to work with a scattered supply chain in terms of different geographical location as it involves lot of time, transportation and risks too and it additionally disputes the total environmental and resilient approach of the supply chain and moreover to validate the inter-relation between ecological sustainability and resiliency of the supply chain. Based on the case study on two companies having different sizes but similar values towards environment which are also located in different geographical region, we have tried to find out the answers. Companies build up supply chain firstly evaluating flexibility and resiliency of their own supply chain only by considering the technology availability, quality and pricing involved with the product and then they want to be sustainable and resilient by addressing other issues. The main challenges for the companies to alter their position are the product specific characteristics, availability of know-how and the suitable process cost involved with product. It has proposed for the companies who are working with numerous supply chains located in different geographical location to do some adjustments among their nearby suppliers for a typical product on experimental basis especially providing technological and logistics support to their suppliers to attain more concrete approach towards their values that they believe. / Program: Magisterutbildning i Applied Textile Management

No Brasil, atualmente só há um laboratório de calibração de monitores de radiação de nêutrons, sendo responsável pela guarda e manutenção do padrão brasileiro da fluência de nêutrons, localizado no Laboratório Nacional de Metrologia das Radiações Ionizantes (LNMRI), Rio de Janeiro, no Instituto de Radioproteção e Dosimetria, Comissão Nacional de Energia Nuclear, Rio de Janeiro, com uma demanda grande de serviços com esse tipo de radiação. Com o intuito de descentralizar a oferta de serviços de calibração, surgiu a necessidade da montagem de um segundo Laboratório de Calibração com Nêutrons (LCN), no IPEN. Nas situações práticas envolvendo a calibração de monitores de radiação de nêutrons, um dos problemas principais está relacionado à radiação espalhada, que pode variar dependendo das dimensões do laboratório usado nos procedimentos de calibração. No processo de caracterização do campo de radiação de nêutrons da fonte de 241AmBe, onde foi realizada a avaliação dos espectros, das energias, das taxas de fluência, das taxas de equivalente de dose ambiente [H*(10)] e do coeficiente de conversão de fluência em dose [h*φ(10)] em diferentes posições do LCN, utilizando o feixe completo. A influência da radiação espalhada foi determinada por meio de três técnicas: Métodos de Monte Carlo, de Ajuste Reduzido e do Cone de Sombra. Dos resultados obtidos por meio de simulação e experimentalmente foi possível obter a fração de espalhamento em diferentes distâncias fonte-detector. / In Brazil, there is currently only one calibration laboratory for neutron radiation monitors. It is responsible for the custody and maintenance of the Brazilian neutron fluence standard, located at the Laboratório Nacional de Metrologia das Radiações Ionizantes-LNMRI, Rio de Janeiro, at the Instituto de Radioproteção e Dosimetria, Comissão Nacional de Energia Nuclear, with a great demand of services with this type of radiation. In order to decentralize the calibration service offer, it was necessary to set up a second Neutron Calibration Laboratory (LCN), at IPEN. In practical situations involving the calibration of neutron radiation monitors, one of the main problems is related to scattered radiation, which may vary depending on the size of the laboratory used for the calibration procedures. In the process of characterization of the neutron radiation field of the 241AmBe source, the spectra, the energies, the fluence rate, the ambient dose equivalent rate and the conversion coefficient of fluence in dose at different positions of the LCN, were evaluated using the complete beam. The influence of the scattered radiation was determined by three techniques: Monte Carlo Method, the Reduced Adjustment Method and the Shade Cone Method. From the results obtained through simulation and experimentally, it was possible to obtain the scattering fraction at different source-detector distances.

Os centros operacionais e de pesquisa em previsão numérica do tempo geralmente trabalham com uma grande quantidade de dados complexos multivariados, tendo que interpretá-los num curto espaço de tempo. Técnicas de visualização científica podem ser utilizadas para ajudar a entender o comportamento atmosférico. Este trabalho descreve a arquitetura e as facilidades apresentadas pelo sistema VisualMet, que foi implementado com base em um estudo das tarefas desenvolvidas pelos meteorologistas responsáveis pelo 8º Distrito de Meteorologia, em Porto Alegre. Este centro coleta dados meteorológicos três vezes ao dia, de 32 estações locais, e recebe dados similares do Instituto Nacional de Meteorologia, localizado em Brasília, e do National Meteorological Center, localizado nos Estados Unidos. Tais dados são resultados de observações de variáveis tais como temperatura, pressão, velocidade do vento e tipos de nuvens. As tarefas dos meteorologistas e as classes de dados foram observadas e analisadas para definir as características do sistema. A arquitetura e a implementação do VisualMet seguem, respectivamente, uma abordagem orientada a ferramentas e o paradigma de programação orientada a objetos. Dados obtidos das estações meteorológicas são instancias de uma classe chamada "Entidade". Três outras classes de objetos representando ferramentas que suportam as tarefas dos meteorologistas foram modeladas. Os objetos no sistema são apresentados ao usuário através de duas janelas, "Base de Entidades" e " Base de Ferramentas". A implementação da "Base de Ferramentas" inclui ferramentas de mapeamento (para produzir mapas de contorno, mapas de ícones e gráficos), ferramentas de armazenamento (para guardar e recuperar imagens geradas pelo sistema) e uma ferramenta de consulta (para ler valores de variáveis de estações selecionadas). E dada especial atenção a ferramenta de mapa de contorno, onde foi utilizado o método Multiquádrico para interpolação de dados. O trabalho apresenta ainda um estudo sobre métodos de interpolação de dados esparsos, antes de descrever detalhadamente os resultados obtidos com a ferramenta de mapa de contorno. Estes resultados (imagens) são discutidos e comparados com mapas gerados manualmente por meteorologistas do 8º Distrito de Meteorologia. Possíveis extensões do presente trabalho são também abordadas. / The weather forecast centers deal with a great volume of complex multivariate data, which usually have to be understood within short time. Scientific visualization techniques can be used to support both daily forecasting and meteorological research. This work reports the architecture and facilities of a system, named VisualMet, that was implemented based on a case study of the tasks accomplished by the meteorologists responsible for the 8th Meteorological District, in the South of Brazil. This center collects meteorological data three times a day from 32 local stations and receives similar data from both the National Institute of Meteorology, located in Brasilia, and National Meteorological Center, located in the United States of America. Such data result from observation of variables like temperature, pressure, wind velocity, and type of clouds. The tasks of meteorologists and the classes of application data were observed to define system requirements. The architecture and implementation of Visual- Met follow the tool-oriented approach and object-oriented paradigm, respectively. Data taken from meteorological stations are instances of a class named Entity. Three other classes of tools which support the meteorologists' tasks are modeled. Objects in the system are presented to the user through two windows, "Entities Base" and "Tools Base". Current implementation of the "Tools Base" contains mapping tools (to produce contour maps, icons maps and graphs), recording tools (to save and load images generated by the system) and a query tool (to read variables values of selected stations). The results of applying the multiquadric method to interpolate data for the construction of contour maps are also discussed. Before describing the results obtained with the multiquadric method, this work also presents a study on interpolation methods for scattered data. The results (images) obtained with the contour map tool are discussed and compared with the maps drawn by the meteorologists of the 8th Meteorological District. Possible extensions to this work are also presented.

<p>This thesis covers the development of the Reverberation Chamber as a measurement tool for cell phone tests in electronic production. It also covers the development of the Scattered Field Chamber as a measurement tool for simulations of real propagation environments.</p><p>The first part is a more ”general knowledge about Reverberation Chambers”-part that covers some important phenomena like unstirred power and position dependence that might occour in a small Reverberation Chamber used for cell phone tests. Knowing how to deal with these phenomenas, give the possibility to use the chamber as a measurement tool for production tests even though it is too complex for a simple test of the antenna function.</p><p>The second part shows how to alter some important propagation parameters inside the chamber to fit some real world propagation environments. The 3D plane wave distribution, the polarization and the amplitude statistics of the plane waves are all altered with simple techniques that are implementable all together. A small, shielded anechoic box with apertures is used to control 3D plane wave distribution and polarization. Antennas that introduce unstirred power in the chamber are used to control the statistics.</p><p>Keywords: Propagation environment, Mean Effective Gain, Reverberation Chamber, Scattered Field Chamber, Channel model</p>

Mammography screening aims to reduce the number of breast cancer deaths by early detection of the disease, which is one of the leading causes of deaths for middle aged women in the western world. The risk from the x-ray radiation in mammography is relatively low but still a factor in the benefit-risk ratio of screening. The characterization and optimization of a digital mammography system is presented in this thesis. The investigated system is shown to be highly dose efficient by employing a photon counting detector in a scanning multislit geometry. A novel automatic exposure control (AEC) is proposed and validated in clinical practise. The AEC uses the leading detector edge to measure the transmission of the breast. The exposure is modulated by altering the scan velocity during the scan. A W-Al anode-filter combination is proposed. The characterization of the photon counting detector is performed using the detective quantum efficiency. The effect of the photon counting detector and the multislit geometry on the measurement method is studied in detail. It is shown that the detector has a zero-frequency DQE of over 70\% and that it is quantum limited even at very low exposures. Efficient rejection of image-degrading secondary radiation is fundamental for a dose efficient system. The efficiency of the scatter rejection techniques currently used are quantified and compared to the multislit geometry. A system performance metric with its foundation in statistical decision theory is discussed. It is argued that a photon counting multislit system can operate at approximately half the dose compared to several other digital mammography techniques. / QC 20100825

In this work the problem of calibrating Flush Air Data Sensing (FADS) has been addressed. The inverse problem of extracting freestream wind speed and angle of attack from pressure measurements has been solved. The aim of this work was to develop machine learning and statistical tools to optimize design and calibration of FADS systems. Experimental and Computational Fluid Dynamics (EFD and CFD) solve the forward problem of determining the pressure distribution given the wind velocity profile and bluff body geometry. In this work three ways are presented in which machine learning techniques can improve calibration of FADS systems. First, a scattered data approximation scheme, called Sequential Function Approximation (SFA) that successfully solved the current inverse problem was developed. The proposed scheme is a greedy and self-adaptive technique that constructs reliable and robust estimates without any user-interaction. Wind speed and direction prediction algorithms were developed for two FADS problems. One where pressure sensors are installed on a surface vessel and the other where sensors are installed on the Runway Assisted Landing Site (RALS) control tower. Second, a Tikhonov regularization based data-model fusion technique with SFA was developed to fuse low fidelity CFD solutions with noisy and sparse wind tunnel data. The purpose of this data model fusion approach was to obtain high fidelity, smooth and noiseless flow field solutions by using only a few discrete experimental measurements and a low fidelity numerical solution. This physics based regularization technique gave better flow field solutions compared to smoothness based solutions when wind tunnel data is sparse and incomplete. Third, a sequential design strategy was developed with SFA using Active Learning techniques from the machine learning theory and Optimal Design of Experiments from statistics for regression and classification problems. Uncertainty Sampling was used with SFA to demonstrate the effectiveness of active learning versus passive learning on a cavity flow classification problem. A sequential G-optimal design procedure was also developed with SFA for regression problems. The effectiveness of this approach was demonstrated on a simulated problem and the above mentioned FADS problem.

High-resolution seismic images of lithospheric structures allow us to infer the tectonics that modified the lithosphere. We apply such methods to understand Cenozoic modification of the lithosphere by tectonic and magmatic processes in the tectonically active western United States. Using USArray Transportable and Flexible Array data, we present high-resolution images for three regions in this thesis. (1) In the Mendocino triple junction, we use a joint inversion of Rayleigh-wave dispersion data and receiver functions to obtain a new crust and upper Vs model to ~150km depth. The model shows four distinct, young lithosphere-asthenosphere boundary systems. A low-Vs anomaly beneath the Great Valley-Sierra Nevada reconciles existing slab window models with the mantle-wedge geochemical signatures in Coast Range volcanics, and explains the ~3 Myr delay of the onset of volcanism after slab removal. Uppermost mantle low velocities provide evidence for forearc mantle serpentinization extending along the Cascadia margin. (2) In the Colorado Plateau, a Rayleigh wave tomography model sheds light on the volcanism along the margins and plateau uplift. Strong upper mantle heterogeneity across the plateau edge results from the combined effect of a ~200-400 K temperature difference and ~1% partial melt. A ring of low velocities under the plateau periphery suggests that the rehydrated Proterozoic lithosphere is progressively removed by convective processes. Particularly, a high-Vs anomaly imaged beneath the western plateau adds evidence for a downwelling/delamination hypothesis [Levander et al., 2011]. Thermo-chemical edge-driven convection causing localized lithospheric downwelling provides uplift along the margins and magmatic encroachment into the plateau center. (3) In the final study, we developed a 3-D teleseismic scattering wave imaging technique based on the Kirchhoff approximation and 3-D inverse Generalized Radon Transform. Synthetic tests demonstrate higher resolution imaging for continuous, irregular interfaces or localized scatterers, in comparison to conventional methods. Applied to the High Lava Plains dataset, the transmission coefficient structure shows a deepening Moho near 117.6°W and three negative events that correlate well with the Rayleigh wave low-Vs zones. Images made with the Mendocino data clearly show rapidly decreasing lithosphere-asthenosphere boundary depths from the subduction to transform regime.

The finite-difference time domain(FDTD) method is formulated by discretizing Maxwell¡¦s equation over a finite volume and approximating the derivatives with centered difference approximation. The total-field/scattered-field formulation use for simulating the uniform plane wave and the added -source formulation use for simulating the plane wave,compare the result of the electric field within metallic enclosures through aperture excited by uniform plane wave with plane wave,The larger of the exciting plane of the plane wave the more approximate to the result of the uniform plane wave .It must be very large for the induced electrical field within enclosure with a slot which vertical to interference source polarization . Generally speaking, the aperture on the enclosures not the slot but small holes on the condition of don¡¦t know interference source polarization.

Positron emission tomography (PET) is a powerful metabolic imaging modality, which is designed to detect two anti-parallel 511 keV photons origniating from a positron-electron annihilation. However, it is possible that one or both of the annihilation photons undergo a Compton scattering in the object. This is more serious for a scanner operated in 3D mode or with large patients, where the scatter fraction can be as high as 40-60%. When one or both photons are scattered, the line of response (LOR) defined by connecting the two relevant detectors no longer passes through the annihilation position. Thus, scattered coincidences degrade image contrast and compromise quantitative accuracy. Various scatter correction methods have been proposed but most of them are based on estimating and subtracting the scatter from the measured data or incorporating it into an iterative reconstruction algorithm. By accurately measuring the scattered photon energy and taking advantage of the kinematics of Compton scattering, two circular arcs (TCA) in 2D can be identified, which describe the locus of all the possible scattering positions and encompass the point of annihilation. In the limiting case where the scattering angle approaches zero, the TCA approach the LOR for true coincidences. Based on this knowledge, a Generalized Scatter (GS) reconstruction algorithm has been developed in this thesis, which can use both true and scattered coincidences to extract the activity distribution in a consistent way. The annihilation position within the TCA can be further confined by adding a patient outline as a constraint into the GS algorithm. An attenuation correction method for the scattered coincidences was also developed in order to remove the imaging artifacts. A geometrical model that characterizes the different probabilities of the annihilation positions within the TCA was also proposed. This can speed up image convergence and improve reconstructed image quality. Finally, the GS algorithm has been adapted to deal with non-ideal energy resolutions. In summary, an algorithm that implicitly incorporates scattered coincidences into the image reconstruction has been developed. Our results demonstrate that this eliminates the need for scatter correction and can improve system sensitivity and image quality. / February 2016