The present understanding of the structure and dynamics of turbulent boundary layers on aerodynamically smooth walls has been clarified over the last decade or so. However, the dynamics of turbulent boundary layers over rough surfaces is much less well known. Nevertheless, there are many industrial and environmental flow applications that require understanding of the mean velocity and turbulence in the immediate vicinity of the roughness elements.</p> <p>This thesis reports the effects of surface roughness on the flow characteristics in a turbulent boundary layer. Both experimental and numerical investigations are used in the present study. For the experimental study, comprehensive data sets are obtained for two-dimensional zero pressure-gradient turbulent boundary layers on a smooth surface and ten different rough surfaces created from sand paper, perforated sheet, and woven wire mesh. The physical size and geometry of the roughness elements and freestream velocity were chosen to encompass both transitionally rough and fully rough flow regimes. Three different probes, namely, Pitot probe, single hot-wire, and cross hot-film, were used to measure the velocity fields in the turbulent boundary layer. A Pitot probe was used to measure the streamwise mean velocity, while the single hot-wire and cross hot-film probes were used to measure the fluctuating velocity components across the boundary layer. The flow Reynolds number based on momentum thickness, , ranged from 3730 to 13,550. The data reported include mean velocity, streamwise and wall-normal turbulence intensities, Reynolds shear stress, triple correlations, as well as skewness and flatness factors. Different scaling parameters were used to interpret and assess both the smooth- and rough-wall data at different Reynolds numbers, for approximately the same freestream velocity. The appropriateness of the logarithmic law and power law proposed by George and Castillo (1997) to describe the mean velocity in the overlap region was also investigated. The present results were interpreted within the context of the Townsends wall similarity hypothesis. </p> <p>Based on the mean velocity data, a novel correlation that relates the skin friction to the ratio of the displacement and boundary layer thicknesses, which is valid for both smooth- and rough-wall flows, was proposed. In addition, it was also found that the application of a mixed outer scale caused the velocity profile in the outer region to collapse onto the same curve, irrespective of Reynolds numbers and roughness conditions. The present results showed that there is a common region within the overlap region of the mean velocity profile where both the log law and power law are indistinguishable, irrespective of the surface conditions. For the power law formulation, functional relationships between the roughness shift, and the power law coefficient and exponent were developed for the transitionally rough flows. The present results also suggested that the effect of surface roughness on the turbulence field depends to some degree on the specific characteristics of the roughness elements and also the component of the Reynolds stress tensor being considered. </p> <p>In the case of the numerical study, a new wall function formulation based on a power law was proposed for smooth and fully rough wall turbulent pipe flow. The new formulation correctly predicted the friction factors for smooth and fully rough wall turbulent pipe flow. The existing two-layer model realistically predicted the velocity shift on a log-law plot for the fully rough turbulent boundary layer. The two-layer model results also showed the effect of roughness is to enhance the level of turbulence kinetic energy and Reynolds shear stress compared to that on a smooth wall. This enhanced level extends into the outer region of the flow, which appears to be consistent with present and recent experimental results for the boundary layer.

Bidirectional reflectance is a fundamental radiative property of rough surfaces. Knowledge of the bidirectional reflectance is crucial to the emissivity modeling and heat transfer analysis. This thesis concentrates on the modeling and measurements of the bidirectional reflectance for microrough silicon surfaces and on the validity of a hybrid method in the modeling of the bidirectional reflectance for thin-film coated rough surfaces. The surface topography and the bidirectional reflectance distribution function (BRDF) of the rough side of several silicon wafers have been extensively characterized using an atomic force microscope and a laser scatterometer, respectively. The slope distribution calculated from the surface topographic data deviates from the Gaussian distribution. Both nearly isotropic and strongly anisotropic features are observed in the two-dimensional (2-D) slope distributions and in the measured BRDF for more than one sample. The 2-D slope distribution is used in a geometric-optics based model to predict the BRDF, which agrees reasonably well with the measured values. The side peaks in the slope distribution and the subsidiary peaks in the BRDF for two anisotropic samples are attributed to the formation of {311} planes during chemical etching. The correlation between the 2-D slope distribution and the BRDF has been developed. A boundary integral method is applied to simulate the bidirectional reflectance of thin-film coatings on rough substrates. The roughness of the substrate is one dimensional for simplification. The result is compared to that from a hybrid method which uses the geometric optics approximation to model the roughness effect and the thin-film optics to consider the interference due to the coating. The effects of the film thickness and the substrate roughness on the validity of the hybrid method have been investigated. The validity regime of the hybrid method is established for silicon dioxide films on silicon substrates in the visible wavelength range. The proposed method to characterize the microfacet orientation and to predict the BRDF may be applied to other anisotropic or non-Gaussian rough surfaces. The measured BRDF may be used to model the apparent emissivity of silicon wafers to improve the temperature measurement accuracy in semiconductor manufacturing processes. The developed validity regime for the hybrid method can be beneficial to future research related to the modeling for thin-film coated rough surfaces.

In this dissertation, we present a collection of manuscripts describing the development of prognostic models designed to assist clinical decision making. This work is motivated by limitations of commonly used techniques to produce accessible prognostic models with easily interpretable and clinically credible results. Such limitations hinder prognostic model widespread utilization in medical practice. Our methodology is based on Rough Set Theory (RST) as a mathematical tool for clinical data anal- ysis. We focus on developing rule-based prognostic models for end-of life care decision making in an effort to improve the hospice referral process. The development of the prognostic models is demonstrated using a retrospective data set of 9,103 terminally ill patients containing physiological characteristics, diagnostic information and neurological function values. We develop four RST-based prognostic models and compare them with commonly used classification techniques including logistic regression, support vector machines, random forest and decision trees in terms of characteristics related to clinical credibility such as accessibility and accuracy. RST based models show comparable accuracy with other methodologies while providing accessible models with a structure that facilitates clinical interpretation. They offer both more insight into the model process and more opportunity for the model to incorporate personal information of those making and being affected by the decision.

No description available.

The hydrodynamic effects of long-line mussel farms are studied through a two-pronged approach. Large-scale hydrodynamic effects are investigated through the use of field measurements, primarily at a large mussel farm in Golden Bay, New Zealand (230 long-lines, covering an area of 2.45 km by 0.65 km). The research focuses on three areas: the effect of the farm on currents, mixing and stratification, and the dissipation of wave energy. Measurements are also made of the forces on long-line anchor ropes, and a limited investigation is made of phytoplankton depletion. The second approach is the use of laboratory drag measurements and Particle Tracking Velocimetry (PTV) to study the effect of mussel dropper (vertical lengths of mussel-encrusted crop rope) roughness and spacing on flow at small scales. These experiments provide data on very rough cylinders, and on cylinder arrays. The field measurements show that the local effects of mussel farms on currents are significant, but that magnitudes of the effects depend on dropper density, mussel sizes, orientation of the long-lines to the flow, and other parameters that are necessary to characterise the complex interactions between a farm and the flow. The drag on the submerged structures reduces water velocities within the Golden Bay farm by between 47% and 67%. Mussel farms present a porous obstacle to the flow, and flow that does not pass through the farm must be directed around or beneath it. The field measurements indicate that at the study site, most of the flow is diverted around the farm despite its large horizontal dimensions. The droppers at the study site extend over most of the water column (average dropper length ~ 8 m, average water depth ~ 11 m), providing a restriction to the flow beneath the farm. The strength of the density stratification may also favour a horizontal diversion. The flow around the farm is essentially two-dimensional. This suggests that two-dimensional numerical models should be sufficient to obtain reasonable predictions of the velocity drop within, and the diversion around, mussel farms. A simple two-dimensional pipe-network model gives reasonable estimates of the velocity within the farm, demonstrating that the drag of the farm may be adequately parameterised through local increases of bed friction. A wake in the form of reduced velocities extends downstream of the farm, and a mixing layer analogy suggests that this wake spreads slowly. The downstream extent of the wake cannot be determined, although it is likely to be limited by the tidal excursion. The degree of vertical mixing caused by the flow through a mussel farm cannot be quantified, although there are clear interactions between the stratification and the farm. Two mixing mechanisms are considered. A shear layer is generated beneath the farm due to the difference in velocities between the retarded flow within the farm and the flow beneath. Shear layers beneath mussel farms are likely to be weak unless the ambient currents are strong. It will be necessary for stratification to be weak or non-existent for this mechanism to generate significant mixing. The second mechanism is smaller-scale turbulence generated by the mussel droppers. Although the efficiency of this form of mixing is likely to be low, the large number of mussel droppers suggests that there will be some enhancement of vertical mixing. Frequency-dependent wave attenuation is recorded, and is predicted with some success by an analytical model. Both the model and the field data show that wave dissipation increases as the wave period decreases. Wave energy dissipation at the study site averages approximately 10%, although the measurements are made during a period of low wave heights (Hs < 0.25 m). Measurements of long-line anchor rope tension at two study sites indicate that the loadings are induced by the tide, currents, and waves. Dynamic wave loadings may be significant, and higher wave forces are measured at the offshore end of a long-line. The issue of seston or phytoplankton depletion is considered briefly through the examination of fluorescence, turbidity, and acoustic backscatter data. Although the results are consistent with a reduction of seston within the farm, differences between the inside and outside of the farm are not statistically significant. Mussel droppers resemble extremely rough circular cylinders, with the mussel shells forming the surface roughness elements. Drag measurements and PTV flow visualisation are used to investigate the importance of the large surface roughness, and the influence of dropper spacing and long-line orientation on flow. Drag measurements conducted with smooth and rough cylinders show that high surface roughness (ks/D ~ 0.092) has little effect on the drag coefficient of single cylinders in the range 4,000 < Re < 13,000, yet increases the drag coefficient of a row of cylinders normal to the flow. High surface roughness on single cylinders has the effect of shortening the near-wake region, increasing the peak turbulent kinetic energy (TKE) behind the cylinder, and decreasing the Strouhal number (St = 0.21, 0.19, 0.17 for ks/D = 0, 0.048, and 0.094 respectively). Arrays of rough cylinders (ks/D = 0.094) demonstrate similar flow characteristics to those of smooth cylinders. At cylinder spacings of S/D < 2.2, the surface roughness acts to favour the formation of a particular metastable wake pattern, whereas different metastable wake patterns are formed each run behind the smooth cylinders. The experiments show that the drag on single row arrays of cylinders are related to the cylinder spacing (increasing drag with decreasing spacing), and the drag also varies with the sine of the angle to the flow, except where the array is at low angles to the flow. The PTV measurements provide new data regarding the two-dimensional distributions of velocity, TKE, and turbulence statistics behind the cylinder arrays.

An indoor environment could be defined by a complex layout in a compact space. Since mobile robots can be used as substitute for human beings to access harmful and inaccessible locations, the research of autonomous indoor navigation has attracted much interest. In general, a mobile robot navigates in an indoor environment where acquired data are limited. Furthermore, sensor measurements may contain errors in a number of situations. Therefore, the complexity of indoor environment and ability of sensors have determined that it is an insufficient to merely compute with data. This thesis presents a new rough-fuzzy approach to perception-based computing for an indoor navigation algorithm. This approach to perceptual computing is being developed to store, analyze and summarize existing experience in given environment so that the machine is able to detect current situation and respond optimally. To improve uncertainty reasoning of fuzzy logic control, a rough set theory is integrated to regulate inputs before applying fuzzy inference rules. The behaviour extraction is evaluated and adjusted through entropy-based measures and multi-scale analysis. The rough-fuzzy based control algorithm aims to minimize overshoot and optimize transient-state period during navigation. The proposed algorithm is tested through simulations and experiments using practical common situations. The performance is evaluated with respect to desired path keeping and transient-state adaptability.

In this work, it was studied theoretically and experimentally biospeckle technique for analysis of rough surface with application to the investigation of biological activity. The theoretical study was conducted using light scattering theory, in particular a first order perturbation method, seeking to obtain the scattering cross-section per unit area of rough surface. Once given the cross-section, it was possible to obtain the distribution of intensities in a certain region of space as a function of time, allowing the comparison of different light distributions in different instants. The experimental investigation was made from the comparison of speckle patterns recorded (by a CCD camera) at different time instants produced from scattering of coherent light at 635 nm from a freshly harvested plant leaf. The parameter of comparison used was the Pearson correlation coefficient. The experimental result obtained from the correlation coefficient versus time showed a temporal evolution type exponential decay, indicating a degradation behavior of the leaf chemically active and regulated by equations rate. The theoretical result of the correlation function of time, obtained by simulation, also showed a behavior type exponential decay indicating a good agreement with experimental results. / Nesta dissertação, foi estudada teórica e experimentalmente a técnica de biospeckle para análise de superfície rugosa com aplicação na investigação de atividade biológica. O estudo teórico foi feito usando teoria de espalhamento da luz, em particular usando método perturbativo de primeira ordem, buscando obter a seção de choque de radiação espalhada por unidade de área da superfície rugosa. Uma vez determinada a seção de choque, foi possível obter a distribuição de intensidades numa certa região do espaço, em função do tempo, permitindo a comparação das diferentes distribuições de luz em instantes distintos. A investigação experimental foi feita a partir da comparação de padrões de speckles gravados (por uma câmera CCD) em diferentes instantes de tempo originados do espalhamento de luz coerente em 635 nm, a partir de uma folha vegetal recém colhida. O parâmetro de comparação usado foi o coeficiente de correlação de Pearson. O resultado experimental obtido do coeficiente de correlação em função do tempo mostrou uma evolução temporal do tipo exponencial decrescente, indicando um comportamento de degradação da folha quimicamente ativo e regido por equações de taxas. O resultado teórico do coeficiente de correlação em função do tempo, obtido por meio de simulação, também evidenciou o comportamento exponencial decrescente indicando uma boa concordância com o resultado experimental.

Dans cette thèse nous nous proposons de donner certaines applications et généralisations de la théorie des chemins rugueux contrôlé, qu’on peut résumer en trois thèmes : - Obtention d’une « bonne » notions de draps rugueux ce qui permet la construction d’une intégrale plane diriger par des bruit très irrégulier et obtenir une formule de changement de variable pour un drap Brownien fractionnaire ou plus généralement un drap Gaussien.- Construction de solution local et global pour une large classe d’équations aux dérivée partielle dispersive présentant des modulation irrégulière en utilisant l’intégrale de Young non linéaire et la notion de chemin contrôlé. - Interprétation rigoureuse de l’équation de quantisation stochastique en dimension 3 et la construction d’une solution local pour cette dernière en utilisant le notion de distribution contrôlé. / In this thesis we propose to give some applications and generalizations of the theory of controlled rough paths, which can be summarized under three headings :- Getting a "good" notions of rough sheet which allows the construction of two dimensional integral driven by an irregular noise andobtain a change of variable formula for the fractional Brownian sheet or more generally a Gaussian sheet.- Construction of local and global solution for a large class of dispersive equations with an irregular modulation in the dispersion term using the nonlinear Young integral and the notion of controlled path.- Rigourous Interpretation of the stochastic quantization equation in the 3 dimensional torus and the construction of a local solution for this equation using the notion of controlled distribution.

abstract: A domain decomposition method for analyzing very large FDTD domains, hundreds of thousands of wavelengths long, is demonstrated by application to the problem of radar scattering in the maritime environment. Success depends on the elimination of artificial scattering from the “sky” boundary and is ensured by an ultra-high-performance absorbing termination which eliminates this reflection at angles of incidence as shallow as 0.03 degrees off grazing. The two-dimensional (2D) problem is used to detail the features of the method. The results are cross-validated by comparison to a parabolic equation (PE) method and surface integral equation method on a 1.7km sea surface problem, and to a PE method on propagation through an inhomogeneous atmosphere in a 4km-long space, both at X-band. Additional comparisons are made against boundary integral equation and PE methods from the literature in a 3.6km space containing an inhomogeneous atmosphere above a flat sea at S-band. The applicability of the method to the three-dimensional (3D) problem is shown via comparison of a 2D solution to the 3D solution of a corridor of sea. As a technical proof of the scalability of the problem with computational power, a 5m-wide, 2m-tall, 1050m-long 3D corridor containing 321.8 billion FDTD cells has been simulated at X-band. A plane wave spectrum analysis of the (X-band) scattered fields produced by a 5m-wide, 225m-long realistic 3D sea surface, and the 2D analog surface obtained by extruding a 2D sea along the width of the corridor, reveals the existence of out-of-plane 3D phenomena missed by the traditional 2D analysis. The realistic sea introduces random strong flashes and nulls in addition to a significant amount of cross-polarized field. Spatial integration using a dispersion-corrected Green function is used to reconstruct the scattered fields outside of the computational FDTD space which would impinge on a 3D target at the end of the corridor. The proposed final approach is a hybrid method where 2D FDTD carries the signal for the first tens of kilometers and the last kilometer is analyzed in 3D. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2018

Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-09-03T15:49:55Z No. of bitstreams: 1 robertomalheirosmoreirafilho.pdf: 1784153 bytes, checksum: 65d1abd13eb713e62923e5d3c4d69acf (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-09-03T15:53:44Z (GMT) No. of bitstreams: 1 robertomalheirosmoreirafilho.pdf: 1784153 bytes, checksum: 65d1abd13eb713e62923e5d3c4d69acf (MD5) / Made available in DSpace on 2018-09-03T15:53:44Z (GMT). No. of bitstreams: 1 robertomalheirosmoreirafilho.pdf: 1784153 bytes, checksum: 65d1abd13eb713e62923e5d3c4d69acf (MD5) Previous issue date: 2012-07-30 / PROQUALI (UFJF) / A criação de regras de apoio à decisão com base em sistemas de informação é o objeto central da Teoria dos Conjuntos Aproximativos - TCA (Rough Sets Theory). Um trabalho apresentado por Pawlak em 1982 deu início a diversos estudos com o objetivo de criar regras de decisão baseadas em sistemas de informações com múltiplos atributos condicionantes e um ou mais atributos de decisão. Ao longo do tempo, os atributos com relação de dominância, onde há uma escala de valores, vêm recebendo destaque. Para lidar com este tipo de dados foi desenvolvido a DRSA (Dominance-based Rough Sets Approach). O excessivo rigor exigido para a criação de regras pela proposta básica do DRSA fez com que novas propostas surgissem. Além das regras determinísticas, com 100% de certeza, surgiram regras probabilísticas, com algum percentual controlado de incerteza. Existem algumas vertentes de estudo de aplicações de DRSA e a abordagem aqui proposta explora a possibilidade de aumento na qualidade da aproximação e, consequentemente, na qualidade das regras geradas, considerando a possibilidade de união de algumas classes do atributo de decisão com princípio de dominância. Com isto, são preservados os princípios do uso de DRSA. De acordo com a necessidade do pesquisador, a redução de classes pode ser utilizada em conjunto com as outras alternativas de DRSA apresentadas até o momento. Duas novas propostas de união de classes do atributo do critério de decisão são apresentadas, comentadas e criticadas nesta tese, uma baseada em função densidade de probabilidades e outra baseada em transformações probabilísticas. / Creating rules for the support of the decision process is the main subject of Rough Sets Theory. The study first published by Pawlak in 1982 was a catalyst of several studies focusing on creating rules for the support of the decision making process based on multiple attributes conditioning one or more decision attributes. As the studies evolved, attributes with the feature of dominance – attributes measured in some scale – have caught attention. This gave rise to DRSA (Dominance-based Rough Sets Approach). The excessively strict guidelines of DRSA original studies led to the creation of new guidelines that consider not only deterministic rules – 100% certainty – but also probabilistic rules, which account for a certain degree of uncertainty. There are other developments of DRSA and the approach here taken evaluates alternatives for enhancing the quality of the approximation evaluation, therefore enhancing the quality of the rules, by clustering classes of values of decision attributes without compromising the guiding principles of DRSA. According to the need of researcher, the reduction of classes can be used in conjunction with other alternatives of development of DRSA. Two different proposals for the clustering of attributes are presented and evaluated in this study, one based on density functions and the other based on probabilistic transformations.