Previous research suggests learning of children with autism often fails to successfully generalize across changes in settings and stimuli. Much of this research has assessed generalization by first teaching a behavior in one context and then measuring the transfer of the behavior to extra-treatment stimuli and settings. The present study measured generalization of learned behavior by systematically varying the tone of an auditory stimulus present during training to obtain generalization gradients. Generalization gradients are graphical representations of the strength of a response produced by stimuli that vary from the training stimulus along some stimulus dimension. By obtaining generalization gradients, this research may offer a more precise means of characterizing the extent of generalization and the basic processes underlying it. The study also went beyond previous research with children with autism by examining the effects of two different training procedures upon the resulting generalization gradients. Participants were first taught to discriminate between the presence and absence of a specific stimulus, and later, to discriminate between two stimuli varied along the same dimension. Gradients were measured following both trainings. In the first training procedure, three children with autism were taught to engage in a simple communicative request in the presence of a specific tone and to withhold the request when there was no tone. The researchers then measured the extent to which these children continued to engage in the request as the tone was changed in frequency. They graphed the resulting data in the form of a generalization gradient. Although the shape of resulting generalization gradients differed between participants, all three participants in the present study showed a pattern of responding consistent with generalization. Gradients for two of three participants were orderly and decremental. In the second training procedure participants were taught to discriminate between two tones of different frequencies. Generalization gradients were again obtained. Predictable changes in the shape of gradients, consistent with basic research on generalization gradients, were noted for two of three participants. Results are discussed with regard to stimulus control, the behavioral processes of reinforcement and extinction, and what has been called the "peak shift" effect.

Decades of research have fostered a greater understanding of the environmental controls that drive tropical cyclone (TC) intensity change, yet the community has achieved only small improvements in intensity forecasting. Numerous environmental factors impact TC intensity, such as vertical wind shear and sea surface temperatures (SSTs), but little research has focused on establishing if SST change under the TC, or SST gradients, influence these intensity changes. This study investigated three methods to compute SST gradients. The first method calculated the SST change within fixed distances along the track. In the second and third methods, the SST was calculated over the distance traversed by the TC in two separate six-hour periods. By examining 455 24-hour weakening episodes in the eastern North Pacific, this study revealed that the first SST gradient method explained the highest 24-hour weakening variance for TCs located within SSTs at or lower than 26.5 degrees C.

Strawberry is an important cash crop in California, and its supply accounts for 80% of the US market [2]. However, in current practice, strawberries are picked manually, which is very labor-intensive and time-consuming. In addition, the farmers need to hire an appropriate number of laborers to harvest the berries based on the estimated volume. When overestimating the yield, it will cause a waste of human resources, while underestimating the yield will cause the loss of the strawberry harvest [3]. Therefore, accurately estimating harvest volume in the field is important to farmers. This paper focuses on an image-based solution to detect strawberries in the field by using the traditional computer vision technique and deep learning method. When strawberries are in different growth stages, there are considerable differences in their color. Therefore, various color spaces are first studied in this work, and the most effective color components are used in detecting strawberries and differentiating mature and immature strawberries. In some color channels such as the R color channel from the RGB color model, Hue color channel from the HSV color model, 'a' color channel from the Lab color model, the pixels belonging to ripe strawberries are clearly distinguished from the background pixels. Thus, the color-based K-mean cluster algorithm to detect red strawberries will be exploited. Finally, it achieves a 90.5% truth-positive rate for detecting red strawberries. For detecting the unripe strawberry, this thesis first trained the Support Vector Machine classifier based on the HOG feature. After optimizing the classifier through hard negative mining, the truth-positive rate reached 81.11%. Finally, when exploring the deep learning model, two detectors based on different pre-trained models were trained using TensorFlow Object Detection API with the acceleration of Amazon Web Services' GPU instance. When detecting in a single strawberry plant image, they have achieved truth-positive rates of 89.2% and 92.3%, respectively; while in the strawberry field image with multiple plants, they have reached 85.5% and 86.3%.

Experimental investigations were conducted with and without the presence of the surface-mounted obstacle to quantify its effects on the far wake. The obstacle chosen for this study was a 3:2 elliptical nose NACA 0020 tail wing-body (Rood body), approximately of height equal to the boundary layer thickness at one of the measurement locations of the flow. The experiments were performed by varying the Reynolds number of the flow and manipulating the pressure gradient distributions using a NACA 0012 airfoil placed within the wind tunnel test section. The measurements were acquired utilizing a spanwise traversing boundary layer rake and a point pressure sensing microphone array. The findings reveal that the presence of the obstacle introduces disruptions in the flow, such as vortex and jet regions in the wake. However, the overall flow behavior remains consistent with that of an undisturbed turbulent boundary layer, for varying Reynolds numbers and pressure gradients. Notably, an adverse pressure gradient and lower Reynolds number both accentuate the prominence of the jet and vortex region within the wake, with the trend reversing towards the other end of the spectrum. This behavior is akin to the larger turbulent boundary layer under adverse pressure gradients and lower Reynolds numbers. Furthermore, the presence of obstacles induces an increase in the overall level of the wall pressure spectrum by approximately 2 dB, regardless of the flow condition. Additionally, it leads to a deviation in the slope of the mid-frequency range of the autospectra compared to the smooth wall case. Specifically, the mid-slope frequency of an undisturbed turbulent boundary layer is steeper than that observed in the disturbed wake flow caused by the obstacle. / Master of Science / The interaction between turbulence and aerodynamic surfaces gives rise to wall-pressure fluctuations, which in turn induce structural vibrations and acoustic noise. On surfaces turbulent flows meet, antennae, flaps, and other frequently mounted measuring devices. The flow in their wake is impacted by the coherence of a turbulent boundary layer being disrupted by these impediments mounted on aerodynamic surfaces. They also alter the nature of the pressure fluctuations that are generated on the surface of interest. The far wake of a Rood Body obstacle was studied using a point pressure sensing microphone array and a spanwise traversing boundary layer rake. Experimental measurements were taken for a range of Reynolds numbers and pressure gradient environments at the Virginia Tech Stability Wind Tunnel. Results show that the boundary layer rake measurements resolve the presence of the obstacle wake successfully, by characterizing the wake structures and confirming the presence of jet and vortex regions in the wake of the obstacle. Surface pressure measurements reveal that the presence of the obstacle causes the low-frequency content of the wall pressure to be less dominant than the no obstacle case, while the high-frequency content becomes more dominant in the presence of the obstacle. The presence of obstacles also increases the overall levels of the wall pressure spectrum by approximately 2 dB.

During lithium-ion battery electrode fabrication, slurry drying conditions influence the resulting microstructure of electrodes. It has been found that the drying conditions can result in non-uniform cathode microstructures and material distributions. Accelerated drying, for example, is widely assumed to cause the binder in an electrode to migrate within the slurry, which can contribute to adhesion failure, and ultimately capacity fade and reduced battery life. While there are some conflicting studies regarding the aspects of accelerated drying that cause binder migration, there is not a widely used standard metric for measuring the gradient of binder across the thickness of an electrode. In this work, the vertical heterogeneity of electrodes, as measured using energy-dispersive X-ray spectroscopy (EDX), is correlated with different drying methods and rates. An improved metric for measuring the binder gradient in electrodes is proposed. For the electrodes in this study, binder migration is minimally affected by the drying method and the normalized binder gradient does not increase with increased drying rate. The results are compared to a drying physics model, and it is shown that further development of current models that predict binder gradient as a function of drying rate will need to be modified to more fully capture the physics of slurry drying.

No / The study is based on a previously proposed methodology for multiaxial fatigue life assessment of injection-molded components (called ‘Through Process Modeling’ (TPM)). The present contribution focuses on stress concentration effects induced in notched samples. Purely macroscopic approaches are unable to capture the different mechanical responses of variably injected parts with the same shape. A high interest of the present method is to take into account the difference of fiber orientation resulting from the process. After briefly reminding the TPM method, it will be shown that good lifetime estimations are obtained for laterally injected samples, from a fatigue criterion identification based on longitudinally injected ones.

Ce mémoire rend compte de l'expertise développée par l'auteur au Centre de recherchede l'Institut universitaire en santé mentale de Québec (CRIUSMQ) en endoscopie fibrée. Il décrit la construction d'un nouveau type de microscope optique, le MicroscopeInterstitiel Panoramique (PIM). Par la juxtaposition d'un court morceau de fibre à gradientd'indice et d'un prisme à l'extrémité d'une fibre monomode, la lumière laser estfocalisée sur le côté de la sonde. Pour former une image, cette dernière est rapidementtournée autour de son axe pendant qu'elle est tirée verticalement par un actuateurpiézo-électrique. Ce design de système rotatif d'imagerie interstitielle peu invasif est uneffort pour limiter les dégâts causés par la sonde tout en imageant la plus grande régionpossible en imagerie optique cérébrale profonde. / This thesis documents the expertise developed by the author at the Centre de recherchede l'Institut universitaire en santé mentale de Québec (CRIUSMQ) in fibered endoscopy, particularly the design and construction of a new kind of optical microscope: ThePanoramic Interstitial Microscope (PIM). Through the juxtaposition of a short piece ofGraded-Index fibre and a prism at the end of a single-mode fibre, laser light is focussedon the side of the probe. To form an image, the latter is quickly spun around its axiswhile it is being pulled vertically by a piezoelectric actuator. This minimally invasivefluorescence rotary interstitial imaging system is an endeavor to limit the damage causedby the probe while imaging enough tissue to provide good context to the user in deep brain optical imaging.

Gradients of morphogens, secreted signaling molecules, are crucial for providing cells with positional information during animal development. While the processes of forma- tion and interpretation of these gradients have been extensively studied, the impact of morphogenetic events on patterning through morphogen gradients remains largely unex- plored. This thesis aims to understand the interplay and feedback mechanisms between tissue shape and morphogen gradients formation. To address this, we developed an analysis pipeline using MATLAB to accurately measure morphogen gradients in curved epithelia. By computationally deforming confocal images of curved tissues, we quantified the levels of a protein of interest at a specified distance from a reference point along the apico-basal axis. Applying our pipeline to the Hedgehog morphogen gradient in the Drosophila eye and wing imaginal discs, which serve as model systems for folded and flat epithelial tissues, respectively, we made an intriguing discovery. Despite the distinct morphologies of these tissues, the decay rate of the Hedgehog gradient remained com- parable. This led us to investigate the robustness of Hedgehog gradient formation by manipulating the morphology of the wing and eye discs. We induced ectopic fold forma- tion at the boundary between the source and receiver tissue of Hedgehog in the wing disc. We found that the decay rate of the Hedgehog gradient remained unchanged even in the wing disc with perturbed morphology, supporting the notion that the Hedgehog gradient is robust towards variability in tissue shapes. Additionally, we locally flattened the eye disc by introducing a mutation that inhibited depolymerization of F-actin. This resulted in the inability of cells to form the morphogenetic furrow and in an expansion of the Hedgehog range compared to the wild-type. However, according to our quantifica- tion, the expansion in the Hedgehog range is to be attributed to a shift in its source rather than a change in decay rate of the gradient. Overall, by developing quantitative methods to analyze the distribution of signaling proteins in curved tissues, we contribute to the understanding of the interplay between tissue morphology and pattern formation through morphogen gradients. Our findings highlight the robustness of the Hedgehog gradient formation towards diverse tissue morphologies. This observation leads us to hypothesize that this property of robustness could extend to other morphogens that employ transport mechanisms similar to Hedgehog.:Contents Summary . . . . . . . . . . i 1 Introduction . . . . . . . . . . 1 1.1 Basic principles of animal development: an intricated story . . . . . . . . . . 1 1.2 Epithelial folds: a fundamental building block for morphogenesis . . . . . . . . . . 3 1.3 Patterning via morphogen gradients . . . . . . . . . . 4 1.4 Hedgehog gradient in Drosophila imaginal discs as a model system. . . . . . . . . . 13 2 Aims of the Thesis . . . . . . . . . . 21 2.1 Developing an analysis pipeline to quantify morphogen gradients in curved epithelia. . . . . . . . . . 21 2.2 Assessing the robustness of the Hedgehog morphogen gradient in naturally folded and flat tissues: the eye and wing imaginal discs . . . . . . . . . . 22 2.3 Testing the robustness of the Hedgehog gradient by perturbing the morphology of the wing and eye discs . . . . . . . . . . 22 3 Materials and methods . . . . . . . . . . 25 3.1 Fly stocks. . . . . . . . . . 25 3.2 Immunohistochemistry. . . . . . . . . . 28 3.3 Imaging . . . . . . . . . . 30 3.4 Data analysis. . . . . . . . . . 30 4 Results . . . . . . . . . . 47 4.1 Analysis pipeline to computationally flatten curved epithelial tissues: limitations in applicability and comparison to other methodologies. . . . . . . . . . 47 4.2 The Hedgehog gradient is comparable between wing and eye disc in Drosophila . . . . . . . . . . 54 4.3 The extracellular basal gradient of Hedgehog has a decay rate comparable to the one of the internalized morphogen . . . . . . . . . . 62 4.4 Folds in the wing do not affect the Hedgehog gradient. . . . . . . . . . 66 4.5 Downregulation of ci leads to lower levels of the Hedgehog receptors Ptc, which in turn results in a longer Hedgehog gradient . . . . . . . . . . 71 4.6 Local flattening of the morphogenetic furrow expands the source of Hedge- hog but does not affect the decay rate of the gradient . . . . . . . . . . 74 5 Discussion . . . . . . . . . . 83 5.1 Developing quantitative methods to analyze morphogen gradients in curved epithelia opens new possibilities to study the interplay between morphogens gradients and morphogenesis . . . . . . . . . . 83 5.2 A methodological consideration: the decay rate as a relevant parameter for assessing the robustness of the Hedgehog morphogen gradient . . . . . . . . . . 85 5.3 The decay rate of the Hedgehog gradient is comparable between the wing and the eye disc . . . . . . . . . . 90 5.4 The transport mechanism underlying the formation of the Hedgehog gra- dient in the wing disc is robust towards deformations of the apical side of the tissue . . . . . . . . . . 91 5.5 The capt mutation in the eye disc affects the signaling for differentiation without affecting the decay rate of the Hedgehog gradient . . . . . . . . . . 94 5.6 Active transport and binding to heparan sulfate proteoglypicans allow the Hedgehog morphogen gradient formation to be robust towards variation in tissuemorphology . . . . . . . . . . 98 5.7 Tissue morphology: obstacle or aid to patterning via morphogens . . . . . . . . . . 99 6 Conclusion. . . . . . . . . . 103 7 Acknowledgments . . . . . . . . . . 105 8 References . . . . . . . . . . 107 9 Declaration according to §5.5 of the doctorate regulations . . . . . . . . . . 117

The purpose of our work is to estimate arterial stiffness based on the virtual fields method and using pressure gradients and arterial wall motion. Currently, the gold standard to estimate arterial stiffness relies primarily on the pulse wave velocity, which provides a relation between arterial stiffness and the velocity of the pressure wave propagating through the arterial wall. The pulse wave velocity method has been improved over the years, but still depends on specific assumptions regarding, for example, blood pressure, arterial geometry, and linear material response. The proposed method directly links arterial wall displacements and pressure gradients to arterial stiffness and paves the way to computing arterial stiffness with higher accuracy.

Experimental data from two cold airflow turbine tests were evaluated. The two tests had different, relatively high gradient flow fields at the turbine exit. The objective of the research was to evaluate data requirements, including the averaging techniques, the number of measurements, and the types of measurements needed, for high gradient flow fields. Guidelines could then be established for future tests that could allow reduction in test time and costs. An enormous amount of data was collected for both tests. These test data were then manipulated in various ways to study the effects of the averaging techniques, the number of measurements, and the types of measurements on the turbine efficiency. The effects were evaluated relative to maintaining a specific accuracy (1%) for the turbine efficiency. Mass and area averaging were applied to each case. A detailed uncertainty analysis of each case was done to evaluate the uncertainty of the efficiency calculations. A new uncertainty analysis technique was developed to include conceptual bias estimates for the spatially averaged values required in the efficiency equations. Conceptual bias estimates were made for each test case, and these estimates can be used as guidelines for similar turbine tests in the future. The evaluations proved that mass averaging and taking measurements around the full 360 degree was crucial for obtaining accurate efficiency calculations in high gradient flow fields. In addition, circumferential averaging of wall-static pressure measurements could be used rather than measuring static pressures across the annulus of the high gradient flow field while still maintaining highly accurate efficiency calculations. These are an important finding in that considerable time and cost savings may be realized due to the decreased test time, probe measurements, and calibration requirements.