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Considering the limitations of latency and power consumption in conventional machine vision systems, this thesis investigates a new visual information process scheme with an emerging visual sensor: the Pixel Processor Array (PPA) by directly processing signals where they are collected, hence avoiding the aforementioned issues with conventional machine vision systems. In particular, this thesis establishes mobile robotic control systems with on-sensor computed results for multiple navigation research. Then, our work investigates novel parallel visual inference approaches, with a particular emphasis on parallel machine vision algorithms and cutting-edge machine learning-based algorithms. Specifically, we are motivated to perform neural networks to extract higher-level helpful information from the analogue signals. An edge computing platform can be established based on our neural network with the PPA, where only a small quantity of extracted information is obtained, allowing for more efficient data transmission with less bandwidth. Hence, this thesis presents a lightweight and high-speed binary convolutional neural network on the sensor to categorise a range of objects. With the proposed methods to implement networks, all floating-point time-consuming multiplication operations can be replaced by efficient addition/subtraction and bit shifting operations. The focal-plane visual inference is difficult due to hardware resource constraints, such as limited registers and analogue noises. Hence, this work further proposes the purely binarised convolutional neural networks with both binary weights and activations. This thesis trains and implements neural networks with batch normalisation and adaptive threshold to binarise activations. The binary activations on the sensor benefit the neural network performance by alleviating the noises introduced by using analogue signals.

Hydraulic fracturing has attracted a tremendous amount of attention due to its abundant applications, such as magma-driven dykes, fracturing of oil and gas reservoirs, heat production from geothermal reservoirs, ice melt, and fault reactivation in mining. Therefore, the development of fracture propagation models is of great significance to provide more effective technical tools for the dynamic simulation of fracture formation and propagation. Hydraulic fracturing involves a complex process due to the strong coupling between the fluid and solid rock. The finite element method (FEM) is a traditional method for solving the fracture propagation problem. FEM has the advantage of being robust and flexible. However, special treatment is required when dealing with complex fracture problems such as fracture intersection and branching because of discontinuities across fracture surfaces. Instead of seeking to approximate partial differential equations in a conventional framework, the peridynamic approach (PD) uses spatial integral equations that overcome the limitations of defining partial derivatives at discontinuities, which makes it quite suitable for solving complex fracture problems. Therefore, it is of great importance to combine the advantages of both FEM and PD to develop a more robust and flexible fracture propagation model. The main contribution of the thesis is to study fracture propagation problems in fully saturated porous media based on both FEM and PD. Three fracture models based on FEM, PD, hybrid FEM and PD are developed to simulate and explore more "realistic" fracture propagation processes. The main research work of the thesis contains the following four parts. First, comprehensive reviews of the fracture propagation literature, crack branching and PD theory are given. The fracture propagation review includes a review of the fracture propagation process, fracture models and various numerical methods for predicting fracture propagation. The review of crack branching provides a state-of-the-art review of crack branching, including experimental observations, physics, fracture models and associated numerical methods. The latest advances and existing issues of crack branching are discussed. The review of PD theory provides a review of theoretical aspects of PD and related applica-tions of PD in different fields, especially in the field of fracture mechanics. The challenges and new prospects for the development of PD are discussed. Then, a fully implicit, FEM-based fracture model using zero thickness cohesive interface elements is developed. The rock formation is considered as a fully saturated porous medium. The fracture surface is deemed to be permeable, the fracturing fluid is treated as an impressible Newtonian fluid, and the cohesive zone model is employed for the fracture propagation criterion. After verifying the model, the stepwise phenomenon, which has been observed in the field and experiments and reported recently in the numerical modelling literature, is investigated with the model. Then, an explicit PD approach for simulating fracture propagation in saturated porous media is developed. A staggered method is adopted to solve the coupled system. The solid deformation equation is solved for the displacement field, and the fluid flow equation is solved for the pressure field with PD. After verification via benchmark examples, including a 1D consolidation problem and a 2D fluid-filled crack propagation problem, a series of tests are conducted to study the fracture propagation phenomena in porous media, including the crack branching phenomenon and the stepwise phenomenon. Effects of pore pressure in fracture propagation branching are investigated, and the stepwise phenomenon is successfully reproduced. All the examples presented demonstrate the capability of the approach in solving fracture propagation problems in saturated porous media. Finally, a fully coupled hybrid FEM-PD approach for simulating fracture propagation in saturated porous media is presented. Considering the ability of PD in solving discontinuous problems, the area where cracks can potentially occur is discretised by PD and the crack-free area is discretised by FEM. The solid deformation and fracture propagation are captured by PD and FEM, while the fluid flow in both the reservoir and fracture is simulated with FEM. The whole process is solved in a monolithic way with an implicit scheme. The approach demonstrates the capability of modelling complex dynamic crack propagation via benchmark examples. The branching phenomenon is then investigated with the proposed approach. In conclusion, complex crack patterns are prone to form with faster loading rate, more brittle and impermeable media, and with lower energy release rate.

This thesis is motivated by the need to reduce train aerodynamic noise, especially the noise from pantographs and bogies which are comprised of bluff bodies including cuboids. The underlying physics of the flow over cuboids with different cross-sections and the emitted noise are studied. The effects of wall proximity and corner radii on the flow field and noise of a cube as well as the effect of the aspect ratio of cuboids are the main focus. The Delayed Detached Eddy Simulation method is adopted to investigate the flow features and obtain the noise source information. The far-field noise is then predicted using the Ffowcs Williams-Hawkings acoustic analogy. Benchmark comparisons on the flow over a wall-mounted cube and a sphere are conducted to validate the feasibility of the adopted methodology for describing the flow field; a separate simulation on a square cylinder is also implemented to gain confidence in predicting surface pressure fluctuations and the far-field noise. Good agreement has been achieved between results from the benchmark cases and those from the literature. It is found that the wall proximity mainly affects the behaviour of the separated flow from the lower leading edge of the cube and also the flow separation along the ground. Large pressure fluctuations are observed close to the trailing edge and locations of the flow reattachment on the bottom of the cube. With the increase of the elevation height, the sound from the cube increases rapidly in the vertical direction and the maximum sound is observed when the cube is elevated by one quarter of the edge length above the ground. For rounded cubes, the flow separation is delayed with the increase of the corner radius; the shear layer moves towards the lateral surfaces and the recirculation length in the wake reduces. Flow features of the rounded cube vary with the Reynolds number, although no systematic dependence is observed. Large pressure fluctuations are found in the recirculating region on the lateral surface and near the trailing edge due to reduced recirculation length in the wake. Rounding the cube with a suitable radius can be an effective way to reduce the emitted noise. The minimum noise is found for a radius one third of the edge length. Cuboids with different aspect ratios are studied, where the aspect ratio is defined as the ratio of the width in the spanwise direction to the length in the streamwise direction. The flow separated from the upper leading edge only reattaches to the top surface for aspect ratios smaller than 1 whereas the vortex shedding in the wake tends to be more evident as the aspect ratio is increased. The Reynolds number has negligible effect on the mean flow behaviours of the cuboid. Large pressure fluctuations happen with the flow reattachment and the formation of the secondary vortex near the trailing edge. The emitted noise from the cuboid is always higher in the cross-flow direction than that in the streamwise and spanwise directions. The maximum sound is found for the aspect ratio of 6.

Many drugs have poor aqueous solubility which causes problems for their formulation as effective medicines. One way of solving this problem involves solubilizing drugs using aqueous dispersions of self-assembled surfactant micelles. It is well-established that surfactant micelles can solubilize drug, but where the drug will locate within the micelles and the factors that affect this are not fully understood. It is the locus of drug solubilization, however, that is thought to be important in determining the loading-capacity of the micelles, and it is this too that affects the drug's stability and its rate of release inside the body and so it also impacts the drug's therapeutic activity. In order to gain a better understanding of the location of drug in surfactant micelles, a series of systematic studies have been performed to determine the extent and locus of solubilization of two poorly water-soluble steroids, 4-cholesten-3-one (4-CHOL) and adrenosterone (ADRENO) compounds in a range of C12-chain surfactant of varying head group. The solubilisation capacities of steroids in the various surfactant micelle, as well as the interfacial and solvation behaviour of the various surfactant systems were explored. In order to estimate the preferred site(s) of solubilization of the steroids within the micelles, neutron techniques (both small-angle neutron scattering (SANS) and specular neutron reflectivity (SNR)) in combination with isotopic (H/D) contrast variation were used. The NR study revealed that regardless of the nature of the head groups, steroids were solubilised within the hydrophobic chain of surfactant at the air-water interface. The SANS studies were in good agreement with the NR study, and also suggested in some cases the presence of steroids could change the shape of the micelle. The information gained in these studies has provided for a more complete understanding of the relationship between the structure of a surfactant and the structure of the micelles likely to be formed when loaded with steroid drugs, allowing predictions to be made to guide the design of new surfactants to optimize steroid drug loading.

This dissertation aims to investigate the effect size measures of differential item functioning (DIF) detection in the context of cognitive diagnostic models (CDMs). A variety of DIF detection techniques have been developed in the context of CDMs. However, most of the DIF detection procedures focus on the null hypothesis significance test. Few studies investigated the practical significance of DIF items. The probability-based effect size indices (signed and unsigned probability difference: SPD and UPD) were proposed in this study. The estimation accuracy of SPD and UPD, as well as the classification of DIF items, were examined under various conditions. The accuracy of the SPD and UPD estimates was largely satisfactory in the studied conditions. The SPD and UPD indices were used together with the Wald test in detecting DIF in the CDM context. The performance of three DIF detection procedures were compared: the Wald method, the Mantel-Haenszel method matched on the total score (MH-T), and the Mantel-Haenszel method matched on the attribute mastery profiles (MH-P). This study also examined the impact of including effect size measures on the Type I error and power rates of DIF detection. The results showed that the Wald method outperformed the two MH procedures in most conditions. The two MH procedures yielded inflated Type I error when group distributions were unequal, and the power rates were also impaired. Including the effect size measures could substantially reduce the Type I error rates of all three methods. In the meantime, including effect size measures also led to a reduction in power for detecting smaller DIF, while the power rates of large DIF were not affected. Moreover, the Trends of International Mathematics and Science Study (TIMSS) 2007 fourth grade mathematics assessment was used to illustrate how the effect size measures and the significance test are combined in detecting DIF. Implications and recommendations for detecting DIF in the CDM context are provided. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]

This thesis aims to explain the financial behavior of households and individuals in China, with a focus on the effects of the old-age dependency, household composition and healthcare systems. First, we investigate the association between old-age dependency ratio and household savings with 1995-2015 provincial-level panel data in China. The results show a negative association between the old-age dependency and the savings ratio, which is weaker in areas with higher level of government medical expenditure, financial development and insurance density. Second, we examine household composition and consumption with the 2011 and 2013 waves of China Health and Retirement Longitudinal Study (CHARLS). We provide evidence that the reallocation of resources freed up when an offspring moves out depends on the lever’s age. Finally, using the 2011, 2013 and 2015 waves of CHARLS, we evaluate and compare the Urban Employee Basic Medical Insurance (UEBMI) and resident health insurance (RHI) schemes. Estimations show that UEBMI is associated with a higher level of household consumption, the utilization of healthcare services, and medical expenditure (compared to RHI). Additionally, RHI fails to help poor people in purchasing sufficient healthcare, whilst UEBMI encourages rich people to overuse healthcare services.

The geopolitical conditions which led to the creation of NATO in 1949 rapidly disappeared following the fall of the Berlin Wall in 1989. The possibility of the termination of institutionalised US support for European security was seriously raised in this period, as was the possibility of NATO ceasing to exist. However, after progressive transformation, NATO expanded rather than disbanded. It went on to participate in ‘out of area’ actions. All these commitments were accompanied by debates about the purpose of NATO. Relevant debates included continuing tensions between Washington and European capitals over defence spending levels; accusations that the US was using NATO as an instrument of extra-United Nations unilateral power; the preference of Washington immediately after 9/11 for working through ad hoc rather than institutionalised alliance structures; and the developing relationship between NATO and Russia. This research seeks to explain the continuing US commitment to NATO in the post-Cold War era. The initial focus is on the recommitment decisions of the Clinton administration. It also researches in some depth the operations in Kosovo and, in particular, Libya. The case study on Libya is especially important in exploring the Obama administration’s understanding of the purpose of NATO in the context of current economic pressures, domestic US debates about post-War on Terror interventions, and of increasing American preoccupation with Pacific rather than European security. In the light of NATO operations in the post-Cold War era and the recent Syrian and Ukrainian crises, the study argues that the US has always been committed to NATO due to the unique value of NATO; the US overall foreign policy preference for NATO; and internal bureaucratic compromise on NATO. But the US may suspend its support to the Alliance in the future if the inherent problem of burden-sharing is not seriously treated by the European members.

At the outset of my PhD, my aim was to investigate the mechanisms responsible for the directed migration of primitive myeloid cells (PMCs) to wounds in Xenopus embryos. PMCs are the first blood cells to differentiate and become functional in Xenopus embryos, and have a notable migratory ability to be recruited by embryonic wounds before a functional vasculature is established. To find the mechanism underlying PMCs migration toward embryonic wounds, I first performed a screen to identify candidate cytoskeleton related genes, which might be responsible for facilitating the inflammatory response to injury in embryos. In situ hybridization and RT-PCR showed that coronin1a and l-plastin were specifically expressed in PMCs. I carried out loss-of-function experiments for coronin 1a and l-plastin in Xenopus embryos. Unfortunately neither knockdown affected the ability for PMCs to migrate during embryonic development or during the wound healing process. Loss-of-function experiments on coronin 1a and l-plastin also did not affect epidermal wound closure speed. Thus, although coronin 1a and l- plastin are expressed specifically in PMCs, they do not appear to be necessary for the migration of PMCs during development and during wound healing in Xenopuos embryos. Since my initial aim failed to provide insight into the mechanisms that mediate 9the inflammatory response to embryonic wounds, I decided to investigate the function of a previously identified monomeric actin protein during embryonic wound healing and appendage regeneration: namely Thymosin beta4 (Tβ4). In situ hybridization experiments showed that Tβ4 is expressed exclusively in the epidermis of developing frog embryos. Tβ4 knockdown embryos resulted in a significantly delay in the speed of wound closure during the early phase of wound healing. This delay correlated with a decrease in the actin contractile ring at the wound margin. Furthermore I found that the cell shapes of epidermal cells in the Tβ4 knockdown embryos were different from epidermal cells in control embryos. I hypothesize that this reduction caused the actin filaments changes in the epidermal cells, and were responsible for the failure of the cells to form an actin contractile ring, thus delaying the initial speed of wound closure. I tried to confirm that most of these defects specific to Tβ4, by performing rescue experiments with Tβ4 mRNA injections. Furthermore, I discovered that Tβ4 knockdown embryos displayed defects in tail development, including the absence of blood vessel branching within the fin of the tail. Finally, I found that the tails in Tβ4 knocked-down tadpoles failed to regenerate, while tails in control embryos regenerated completely following amputation. Both in situ hybridization and real-time PCR showed that Tβ4 was up regulated in the regenerated part of the tail in Xenopus tadpoles. Together with the tail amputation results, Tβ4 might be important for tail development and regeneration. These findings suggest that Tβ4 might play an important roles in the modulation of the actin cytoskeleton, which are essential for the proper behavior of epidermal cells during wound healing and appendage regeneration.

Environmental genotoxicants/carcinogens in the aquatic environment induce complex detrimental impacts on aquatic organisms. Integrated approach is required to comprehensively assess such impacts in terms of animal and environmental health. Biomarkers at different levels of biological organisations, including clearance rates (at individual level), histopathological alterations (at tissue level), DNA strand breaks using comet assay (at cellular level) and transcriptional alterations of key genes determined by real-time quantitative PCR (at molecular level), were designed and applied to analyse the impacts in marine bivalve: Mytilus sp., a classic bio-indicator species for environmental health monitoring, following exposure to selected environmental contaminants (i.e. Benzo(α)Pyrene (B(α)P), C60 fullerene, and tritium). The performance of biomarkers changed in response to exposures with higher sensitivity for DNA strand breaks and transcriptional alterations of selected genes. In particular, genes representing 7 gene groups (tumour suppressor gene - p53, proto-oncogene - ras, cytochrome P450 family - cyp4y1, MAPKs family - jnk, Bcl-2 family - bax, MDM2 - mdm2 and RAD family - rad51) showed tissue- and chemical-specific expression profiles under selected experimental conditions. A comparison revealed similarity of interplay among these highly conserved genes with mammalian models, suggesting Mytilus sp. could be an ideal model for signalling research in the carcinogenesis process. To my knowledge, this is the first research to detect tissue specific transcriptional alteration of p53 and ras genes in the organism for the analysis of detrimental impacts induced by different environmental genotoxicant/carcinogen exposures. Furthermore, the study is also the first one to include genes which can interplay with each other to function in the regulation of DNA repair, apoptosis and cell cycle arrest in marine organisms. The results suggested that the applied integrated biomarker approach is a comprehensive and sensitive method to monitor environmental health and, marine bivalve Mytilus sp. is an ideal model organism for research on genotoxicant induced carcinogenesis and will shed light on the mechanisms of this complex process in higher organisms, including humans.

This research investigates the relationship between political institutions and economic development and highlights the impact of political institutions on the economic development in China from 1992 to 2004 by discussing the reasons why the present political institutions in China require change. It is argued that political institutions could influence economic progress if the effect and role of political institutions - both positive and negative – is recognised. Two case studies are employed as examples of how the absence of appropriate political institutions affects the positive performance of the economy and how this is associated with China‘s history and the way in which economic reforms have been conducted. It is concluded that under the political monopoly of the single party, economic progress and development will be blocked and hijacked by the authorities and interest groups in China. Since its reform and opening up to the outside world, China‘s economy has so far seen an enormous growth, but these achievements are impressive merely in the short-term, and give a false impression of the economy‘s development. The free market economy system requires political reform but the Chinese Communist Party monopolizes all social resources and engages only in economic reform without political reform. This is what could be termed the “curse of the latecomer”: the long-term interests of the nation have been sacrificed and this may result in many hidden risks or even the failure of long-term development. This research identifies the major factors affecting the development of a country‘s society and economy. Political science theories about property rights and the State, and Institutional Change of New Institutional Economics are used to explain and support the standpoint of this thesis. Two case studies will be used in order to show how these theories are occurring in practice, which are the incidents concerning Yang Rong and Sun Dawu. The former will prove that it is necessary for property rights to be specified and enforced, and it is harmful to economic development when the government uses its political power to intervene in the economy. The latter case study will illustrate that the unfair monopoly and interventionist behaviour of government and a relatively defective legal system are not apt in facilitating the performance of China‘s economy. The conclusions of this study stress that institutions are the determinant of economic performance and that institutional changes are likely to occur when the existing institutions fail to satisfy people‘s demands. Such a development appears essential for China to progress further.

Pregnancy is a fascinating biological process in which the best theory and evidence suggest that the mother and newborn form two divergent processes which are themselves integrated into the surrounding environment. Thus, the early life health profile of a newborn depends closely on that of their mother as well as environmental factors during pregnancy. While many previous studies have provided evidence for such associations, they either tend to have small sample sizes and hence limited statistical power, or only have studied a few of the factors in isolation. In this study, we systematically probed the associations by means of principled Bayesian data analysis on a very large commercial insurance claims dataset based in the United States. After a brief exposition of the prerequisite of the statistical models employed in our study, we first identified newborns in the dataset with potential mothers using appropriate diagnostic codes, which served as the foundation of our subsequent work. Using this matched newborn--mother cohort, we first re-examined more than a hundred previously reported associations between the sex ratio at birth, also known as the secondary sex ratio, with environmental, socioeconomic and other stress factors. By showing that these association did not form discernible patterns that popular adaptive theories of sexual selection predict, we provided further evidence against these theories and call for a reformulation of this particular area of evolutionary theory for humans. To demonstrate further use of the matched cohort, we performed a large cohort study on the associations between early-life neurodevelopmental disorders and maternal immune activation, use of anti-infective prescription and various adverse birth conditions. Echoing recent results suggesting a common aetiology of early life immune system diseases and neurodevelopmental disorders as disruptions to modules of the microbiota--gut--brain axis, our results demonstrated that many risk factors that may be effects of dysbiosis were indeed associated with elevated risks of neurodevelopmental disorders. Finally, we included a preliminary study on using Morgan fingerprints as an efficient method of attaining state-of-the-art predictive performance on a commonly used drug--drug interactions dataset.

Over the past decades, the Kingdom of Saudi Arabia (KSA) has experienced significant growth in fish consumption, leading to an increased importation from various countries to satisfy high domestic demand. Recognizing this trend and aiming at reducing its reliance on global food imports while improving food security, the Saudi government have invested billions of US dollars in developing domestic aquaculture. Rainbow Trout was identified as one high-value fish species that could be produced domestically. The success of the Rainbow Trout depends on Saudi consumers' preferences and their willingness to buy and pay for the domestically produced fish. However, there has been a lack of research on consumer preferences for fish products in KSA. To fill this gap, this study investigates consumer preferences and their willingness to pay (WTP) for domestically produced Rainbow Trout, to support aquaculture expansion in the country. A field experiment was carried out in Riyadh, the capital city, and Jeddah, a coastal city, recruiting 333 consumers in shopping malls and supermarkets. The field experiment is comprised of three stages: i) a blind tasting sensory evaluation of Rainbow Trout and Salmon (benchmark product, which is a well-established type of fish in the KSA); ii) a discrete choice experiments (DCE) focusing on five attributes of Rainbow Trout (price, color, processing form, product form, and origin and quality certification); and iii) a questionnaire on purchasing, consumption habits, and sociodemographic characteristics. The sensory evaluation results indicate that consumers perceive no difference in odor, texture, and the overall taste between Salmon and Rainbow Trout. The DCE results indicate that consumers prefer an orange, fresh, cut in fillet, that contains the SAMAQ-quality KSA certification Rainbow Trout than a white, frozen whole Trout that is imported. Specifically, consumers are willing to pay 39.27 SAR/0.35kg more for an orange Rainbow Trout relative to a white Rainbow Trout. They are willing to pay an additional 29.79 SAR/0.35kg for a fresh Rainbow Trout compared to a smoked Rainbow Trout. Additionally, they are willing to pay 26.70 SAR/0.35kg more for a skinless and boneless fillet thank for a whole fish of the same size, and 17.78 SAR/0.35kg more for a skin-on boneless fillet compared to a whole fish of the same size. A Rainbow Trout produced domestically and SAMAQ certified receives a premium of 23.31 SAR/0.35kg over an imported not-certified Rainbow Trout. These findings provide crucial insights for policymakers in the KSA to assess the viability of the domestic Rainbow Trout aquaculture sector. The findings also provide valuable information for aquaculture businesses as to customize production, pricing, and marketing strategies by producing Rainbow Trout with the most appealing attributes to Saudi consumers. This study is the first of its kind to investigate the preferences of Saudi Arabian consumers regarding domestically produced finfish, making it a groundbreaking contribution to the understanding of local food preferences and purchasing behavior in the KSA.

Crystallization of semicrystalline polymers under flow affects the properties of the final products made from these materials. The growth of polymer crystals occurs through “secondary nucleation,” which is the nucleation of new crystalline layers onto a surface of crystallized polymer chains arising from primary nucleation from the melt. Despite of years of efforts, even for homopolymers, there are still major unresolved issues, including 1) the mechanisms of deposition of the crystalline atoms onto a crystalline surface and what controls its rate, 2) understanding the effect of short-chain branches on crystallization, and 3) developing a method for predicting orientation of commercial polymers under flow, and how this orientation affects crystallization. To address, the first point, namely the mechanisms of secondary nucleation of homopolymers, we simulated alkane (C50 and C100) oligomers near the (100) surface of a hexagonal-packed PE crystal slab of periodic PE chains and our results show that the oligomers rapidly form a nematic interface, which thickens from around two to three layers thick, and crystalline order nucleates from this nematic layer onto the crystal-slab surface, and spreads as a two-dimensional patch. These findings, along with those of Bourque (Macromolecules 2016, 49, 3956–3964) contrast sharply with the stem-by-stem growth assumed in the Hoffman-Lauritzen theory (Polymer 1997, 38, 3151–3212) of secondary nucleation, with the work reported here indicating the importance of the nematic interfacial layer in the propagation of the crystalline front. To address the second point, we presented a method to track within atomistic molecular dynamics simulations the crystal-inclusion of short-chain branches in copolymers, and from this to estimate the corresponding crystal-inclusion energy. We applied the method to ethylene-alpha-olefin random copolymers with short chain branches ranging from methyl to hexyl groups. Snapshots show that, if included into the crystal, side groups larger than methyl need to be accommodated by defects including crystal distortion, chain folding, or chain ends, indicating a dependence on molecular weight of the crystal-inclusion energy. To address the third point, namely, to apply simulations of polymer flow to industrial polymers we developed a method for efficient prediction of the rheology of polydisperse polymers by judicious selection of a small number (around 6-12) of “representative” polymer molecules from the large ensemble of chains comprising the molecular weight and branching distributions. The representative ensemble is selected such that it minimally suffices to predict the linear viscoelasticity that is either measured experimentally or predicted by models that include a much more complete ensemble of chains. The method is tested for several model polymer systems, which has molecular weight ranging from 122 kg/mol to 307 kg/mol and polydispersity ranging from 2.06 to 13.00, including two polydisperse linear polystyrene (PS) samples described in Shivokhin et al. (Polym. Eng. Sci. 2016 56, 1012–1020) and Münstedt (J. Rheol. 1980, 24, 847–867), a commercial linear low-density polyethylene (LLDPE), and a low-density polyethylene (LDPE) whose rheological properties are measured in the current study. The reduction in the number of representative polymer species offers new opportunities for faster simulations of flowing polymers, as well as for the prediction of segmental orientation to be used in the modeling of flow-induced crystallization.

Writing tasks are essential in students’ academic literacy learning experience. An important factor for success with academic writing tasks is task representation, which refers to how students understand the assigned writing tasks. Second language (L2) writing research has taken interest in this topic. However, most research has focused on the issue of task representation among students in higher education, despite the growing presence of multilingual learners in U.S. high schools and the emphasis on writing in high school classrooms.To address this gap, this study explored the issue of task representation among two Chinese “parachute kids” and their writing experiences during their sophomore year in an American high school. The study focused in particular on how the participants constructed and applied task representations for research paper assignments in their English Language Arts (ELA) and U.S. History courses.The data for this research were collected from multiple sources, including semi-structured interviews with the students and their teachers, analysis of the written texts that the students produced, and field notes from classroom observations. Guided by the framework of a social cognitive theory of writing (Flower, 1994), this study examined the students’ engagement with task representation from a cognitive perspective by examining their private composing processes. It also considered the social and cultural factors that contributed to their understanding of and approaches to the assigned writing tasks.The findings revealed that the two “parachute kids” had considerable difficulty in understanding, and thus responding meaningfully to, the assigned writing tasks. They did not construct task representations that aligned with their teachers’ expectations. Their ideas about research paper writing were rooted in notions of informational or descriptive writing, not writing that is analytical or argumentative in nature. That is, they believed their responsibility was to display information, not transform it for some larger purpose. This limited understanding had a significant impact on the writing they produced.Additionally, the findings showed that the two “parachute kid” participants’ encounters with task representation were complex, multi-faceted experiences in which four major factors stood out: teacher influence, their native language (L1) writing experience, their freshman year writing experience in the high school, and their level of task engagement. There were both similarities and differences in how the participants experienced those factors.The study’s findings draw attention to the situated nature of task representation and to the need to account for a host of variables in accounting for the relationship between task representation in L2 academic writing and how Chinese “parachute kids,” as novice L2 writers, approach such writing, especially as related to composing research papers.

This thesis investigates several problems raised in quantum feedback control field, which includes measurement-based feedback control and coherent feedback control. In the field of measurement-based feedback control, the quantum systems with measurement are described by stochastic equations. We consider the stabilization of a target state or space, which includes the Bell states in two-qubit systems and GHZ entangled states for multi-qubit systems. The symmetry of state space and the time delay in feedback loop are two main obstacles in designing measurement-based feedback control. In two-qubit quantum systems, a Bang-Bang controller based on the delayed system state is designed to achieve the preparation of a given Bell state. The control scheme is then extended to multi-qubit systems, where a Bang-Bang controller and a switching Lyapunov controller are designed to stabilise any given GHZ entangled state. Quantum systems are inevitably affected by open environments. This will result in quantum information leakage, which can be represented by a dissipation term in stochastic equations. For open quantum systems, we first investigate the conditions of invariant and attractive subspaces based on the division of the Hilbert space. A Bang-Bang-like controller is then designed to stabilise any given eigenstate of an angular momentum operator for a class of Markovian open quantum systems with time delay in the feedback loop. To avoid the problems of time delay and hardware mismatch caused by quantum measurement, the coherent feedback control strategies have been proposed in quantum control. For a class of linear quantum systems suffering from Markovian faults, we design a coherent feedback controller to achieve the required H^∞ disturbance attenuation performance. The controller is designed by solving a set of linear matrix inequalities (LMIs), and the physical realisability of which is guaranteed theoretically. Furthermore, we apply the developed fault-tolerant control strategy to a quantum Optical Parametric Oscillator (OPO), where the amplitude of the pumping field randomly jumps among different values. A quantum H^∞ controller is then designed, the implementation of which is proposed in quantum optical platforms. When the phase and/or amplitude of the pumping _eld in an OPO have some fluctuations due to a fault signal, a time-varying uncertainty will be introduced in system parameters. We consider to design a fault-tolerant controller for an OPO with a disturbance input and time-varying uncertainties. A passive controller with a simple form and an active controller with a better performance are designed to achieve the required H^∞ performance. The control performance of the controllers is compared in a numerical example, and both these two controllers are implemented in quantum optical systems.

In Neurofibromatosis type 1, NF1 gene mutations in Schwann cells (SC) drive benign plexiform neurofibroma (PNF), and no additional SC changes explain patient-to-patient variability in tumor number. Evidence from twin studies suggests that variable expressivity might be caused by unidentified modifier genes. Whole exome sequencing of SC and fibroblast DNA from the same resected PNFs confirmed biallelic SC NF1 mutations; non-NF1 somatic SC variants were variable and present at low read number. We identified frequent germline variants as possible neurofibroma modifier genes. Genes harboring variants were validated in two additional cohorts of NF1 patients and by variant burden test. Genes including CUBN, CELSR2, COL14A1, ATR and ATM also showed decreased gene expression in some neurofibromas. ATM-relevant DNA repair defects were also present in a subset of neurofibromas with ATM variants, and in some neurofibroma SC. Heterozygous ATM G2023R or homozygous S707P variants reduced ATM protein expression in heterologous cells. In mice, genetic Atm heterozygosity promoted Schwann cell precursor self-renewal and increased tumor formation in vivo, suggesting that ATM variants contribute to neurofibroma initiation. We identify germline variants, rare in the general population, overrepresented in NF1 patients with neurofibromas. ATM and other identified genes are candidate modifiers of PNF pathogenesis.

The sharing of last-level cache (LLC) among different physical cores makes cache vulnerable to side channel attacks. An attacker can get private information about co-running applications (victims) by monitoring their accesses. Cache side channel attacks can be mitigated by partitioning cache between the victim and attacker. However, previous partition works make the incorrect assumption that only the victim's cache misses are visible to attackers. In this work, we provide the key insight that both cache hits and cache misses from the victim are vulnerable. For a cache hit, although it does not affect the existence state, it can still change the replacement state and coherence state, which can also leak information to attackers. Based on this, we propose Invisible-Victim cache (IVcache), a new cache design that can mitigate both traditional LLC attacks and the new variants. IVcache classifies all processes as protected and unprotected. For accesses from protected processes, IVcache handles state changes in a slightly different way to make those accesses absolutely invisible to any other processes. We evaluate the defense effectiveness and performance of IVcache in the gem5 simulator. We show that IVcache can defend against real-world attacks, and that it introduces negligible performance effect to both protected and unprotected processes.

This study investigates predictability of daily streamflow and soil moisture in the Alabama-Coosa-Tallapoosa (ACT) river basin in southeastern United States. The study employs the state-of-the-art National Water Model (NWM), and compares and contrasts effects of initial soil moisture condition with that of seasonal climate forecast on streamflow and the soil moisture forecasts skill. We had designed and implemented seasonal streamflow forecast ensemble experiments following the methodology suggested by Dirmeyer et al. (2013). The study also compares the soil moisture variability in the NWM with the in-situ observations and remote sensing data from the Soil Moisture Active and Passive (SMAP) satellite. The NWM skillfully simulates the observed streamflow in the ACT basin from 1990 to 2018. The soil moisture variability is 46% smaller in the NWM compared with the SMAP data, mainly due to a weaker amplitude of seasonal cycle in the NWM. This study finds that initial soil moisture condition is a major source of predictability for the seasonal streamflow forecast. Contribution of the initial soil moisture condition is comparable or even higher than that of seasonal climate anomalies effects in the dry seasons. Specifically, in the boreal summer season, the initial soil moisture condition contributes to 65%, and 48% improvements in the seasonal streamflow, and soil moisture forecast skill, respectively. This study attributes a higher improvement in the streamflow forecast skill to the lag effects between the soil moisture and streamflow anomalies. Results of this study can inform development and improvement of the operational streamflow forecasting system.

The interaction of light with solid state quasiparticles, such as excitons and plasmons, on the nanometer-femtosecond spatio-temporal scale illuminates ultrafast physical and chemical processes on surfaces. In this thesis, I report on the generation, control, and spatio-temporal evolution of 2D evanescent electromagnetic waves confined at the silver (Ag)/vacuum interface; such fields, known as surface plasmon polaritons (SPPs), have joint particle-wave nature. SPPs are generated by the interaction of light with the collective response of conduction band free-electrons of metals. I image and study the ultrafast dynamics of SPP fields by interferometric time-resolved multi-photon photoemission electron microscopy (ITR-mP-PEEM). First, I report on the generation and propagation of SPPs excited on epitaxially grown Ag nanocrystals. The PEEM images record an interference pattern between SPPs and vacuum light, defined by a mismatch in their propagation wave vectors. Next, I explore the light polarization as a control parameter for the SPP generation, where the in-plane and out-of-plane components of optical electric fields couple differently. For equilateral triangle Ag island samples, the SPP interference patterns strongly depend on both the linear and circular polarizations. For circularly polarized light, the SPP coupling depends on the matching between spin angular momenta (SAM) of light and SPPs. The SAM of evanescent waves like SPPs is transverse and points oppositely when the propagation wave vector is reversed; this is known as the photonic quantum spin Hall effect (QSHE). I demonstrate that QSHE affects the function of an SPP lens coupling structure through a vectorial superposition of longitudinally and transversely coupled SPP waves that are launched by TE waves (s-polarized) and TM waves (p-polarized), respectively. Finally, I combine my understanding of SPP generation and imaging in a normal-incidence PEEM measurement to explore SPP dynamics when formed by an Archimedean spiral coupling structure. The geometrically defined phase structure of such SPP fields generates plasmonic vortices, whose singularities and time evolution are imaged by PEEM. Based on simulations, I conclude that the SPPs SAM distribution at the vortex core has a stable topological texture of a Néel type Skyrmion, and experimentally locate it by imaging the SPP field singularities.

Visual question answering services can help people with visual impairments answer their visual questions by supporting them to submit an image and a question. However, people with visual impairments may not know exactly what is captured in their images, and their questions may not be explicit and specific enough to be answered accurately. In the project, we designed several algorithms to assist people by identifying when to instruct them to take a higher quality image, ask a valid question, or clarify the object of interest. This can help people to make the visual question they asked answerable with a single, unambiguous answer. The algorithms are evaluated based on accuracy and demonstrated to be effective. Finally, we designed a system to interact with users with our algorithms and will implement it for a user study in future work

Abstract: Since their first discoveries in the early 1990s in Canada, pig diseases, especially porcine reproductive respiratory syndrome (PRRS) and porcine circovirus associated disease (PCVAD), have plagued the Canadian pig industry, and the problem became more severe with the onset of porcine epidemic diarrhea (PED) in 2014. In the meantime, the industry has also seen dramatic structural change with a decrease in pig farm numbers and an increase in total pig numbers. Using the census division (CD) level data obtained from the Census of Agriculture Questionnaires, we find not every CD across the country experienced the same type of structural change. Indeed, about 69% of the CDs in Canada went through decreases in both pig farm numbers and pig numbers over the period 1981 to 2016. This research examines how pig diseases (PRRS, PCVAD, and PED) have affected structural change in the Canadian pig industry at the individual census division level while controlling for the effect of other key economic explanatory variables over the period 1981 to 2016. Farm structure in our study is defined by farm size (i.e., average number of pigs per farm), and the impacts of various economic factors including the U.S. country of origin labelling on the industry’s structural change are empirically assessed using random effects generalized least squares models. The empirical results indicate pig diseases did affect the Canadian pig industry’s structure, and they have played a more significant role in the structure of farms in eastern Canada. Given that pig diseases had played a significant role in pig farming operations in some geographical regions in Canada, we further investigate how various factors including: 1) on-farm disease status; 2) management variables; 3) farmers’ knowledge about and attitudes towards various treatment methods play a role in pig farmers’ decisions regarding the uptake of preventive measures. In general, we find : 1) farmers who experienced disease outbreaks are more likely to implement more preventive measures than those haven no experience; 2) farm and farmer characteristics such as production type and operators’ age are important determinants of adoption decisions; and 3) the better the farmers’ knowledge about a particular practice, the stronger their biosecurity behavior.

My dissertation comprises three empirical studies on development and labor economics. The first two essays are in the context of National Employment Guarantee Schemes (thereafter, NREGA) in India. In the first one, I study whether existing inequality hinders the implementations of NREGA, using district-level data on land ownership distribution and the implementations of NREGA. To address potential endogeneity issues, I leverage a historical institution in India, the land revenue collection system established by British colonial rulers during 1750-1861, to construct an instrumental variable for land inequality. Both OLS and instrumental variable results give robust evidence that the concentration of land ownership reduces public works provision. This relationship could be explained by the mechanism that public works schemes raise agricultural wages in the private labor market, thereby incentivizing big landlords to use their political power to oppose this program. This paper provides the first empirical evidence that the concentration of landownership, a proxy for political power, is a hurdle to providing public employment to the poor. In the second essay, I focus on the participants of NREGA and study the wage bargaining effect of participating in NREGA. Using a household level panel and a difference-in-differences framework, I find indirect evidence that participating in NREGA would increase the wage bargaining power for both participants themselves and for their spouses in the private labor market. The third essay focuses on a different social protection policy, minimum wage standards in China. I utilize a spatial lag methodology to study city level strategic interactions in setting and enforcing minimum wage standards during 2004-2012 in China. This analysis finds strong evidence of spatial interdependence in minimum wage standards and enforcement among main cities in China. If other cities decrease minimum wage standards by 1 RMB, the host city will decrease its standard by about 0.7-3.2 RMB. If the violation rate in other cities increases by 1 percentage point, the host city will respond by an increase of roughly 0.4-1.0 percentage points. These interactions suggest the need for policy coordination in labor regulation.

In recent decades, the unprecedented and fast growing urban development in China has brought numerous benefits to the country, but its impact on public health is complex and multifactorial. Increased population density and rural-to-urban migration have a significant impact on infectious disease transmission. As one of the re-emerging vector-borne diseases, hemorrhagic fever with renal syndrome (HFRS) remains a public concern. With the rapid urban growth, coupled with the changing climate and environmental pollution, HFRS cases have continuously emerged in recent years, and the disease endemic has expanded from rural to urban areas and disease distribution has shifted over time. The distribution of HFRS varies geographically, and annual cases exhibit evident bimodal seasonality. Previous studies have identified the spatiotemporal changes in primary and secondary clusters of HFRS and linked pathogen-carrying rodent population, climatic factors (i.e. temperature, precipitation, relative humidity), and socioeconomic variables with the HFRS occurrence. However, few studies have investigated the impact of urban development on the persistence of HFRS endemics, and the influence of large numbers of migrating population on seasonal outbreaks. In our investigations, we simulated disease transmission dynamics using the deterministic compartmental model by separating the susceptible population into urban permanent residents and migrating population, in order to better understand the contributing factors of HFRS recurrent and seasonal variations. The model output indicates that contacts with infected rodents among the susceptible migrating population have significantly contributed to the seasonal outbreaks for all four study areas. City-specific variations in the magnitude of outbreaks are observed and largely affected by different climatic conditions and demographic composition in each city. We conclude that the risk behaviors of the migrating population have primarily driven the seasonal fluctuations in HFRS cases for most endemic cities, but in order to prevent future HFRS endemic both urban permanent residents and migrants need to be targeted based on some city-specific factors. In addition, correlation analyses between climatic factors and captured rodent population were conducted for study areas to examine the influence of environmental factors on rodent population dynamics, which could directly affect HFRS transmission. Results indicate that higher relative humidity (over 50%) and lower precipitation (less than 150mm for northern cities, less than 400mm for southern cities) are preferable conditions for rodent population growth. Based on the city-specific relative humidity and precipitation, temperature that are within the favorable range for each city is positively associated with the number of captured rodents. Hence, the parametrization process of model simulation requires different information to take into consideration different environmental conditions.

RESEARCH QUESTION: How can city-centre public buildings be regenerated in urbanised China? Presently, with the continuous growth of the economy in China, urbanisation has developed rapidly. The increasing urban population has put significant pressure on many of the original public building spaces in the city centres. The pressure of high levels of urbanisation in China not only has severely damaged the original relationship between architecture and the city, but also reduces the quality of life for urban residents. Public buildings and spaces are the places where the population gather together and are vital landmarks of a city. Therefore, there needs to be a harmonious relationship between public building space and the urban fabric, as they manifest the economics and vitality of the city. This project concentrates on how to regenerate the public building spaces in the city centre. It focuses specifically on redesigning Jinan Railway Station (Jinan, Shandong) and its surrounding context. This project is based on the exploration of urbanisation, urban design and public building space theories. Furthermore, it combines the advanced design concepts, some important precedent studies of contemporary railway stations from around the world and the city’s unique cultures to create the appropriate design approaches for the new Jinan Railway Station. The future design intention for the Jinan Railway Station is to entirely remove the original building and replace it with a multi-functional building complex. Traffic system services within the new design include not only trains but also extend to a subway line and space for buses, taxis and private cars. New technology such as E-ticketing and security lights will be used in a variety of public places within the design to make the architectural form and space of the complex more open, also to ensure maximum safety of passengers and commuters. Ultimately, the outcome of this project is a railway station and surrounding transit squares design that responds to the demand for rapid urbanism and promotes effective transportation of people through Jinan city centre. This design will transfer Jinan Railway Station and its surrounding space as an urban landmark station public space that supports a harmonious relationship between Jinan city’s people and the station

In this dissertation, I propose a novel framework for classifying and describing of multivariate data sets based on the number and structure of indexing variables. Using this framework, I then develop a Bayesian generalized bilinear mixed-effects model for multi-indexed multivariate data. I demonstrate this model is able to capture important features of affiliation network data.The proposed novel framework, the multi-indexed multivariate data structure, classifies data into different categories based on the number and structure of indexing variables. I focus on two special cases of this type of data: double-indexed multivariate data with multiple-membership structure (termed Type A) and triple-indexed multivariate data with cross-classified structure (termed Type B). Several illustrative examples of data of these two types are provided.Some existing multivariate statistical methods, which are appropriate for analyzing Type A or Type B data, are reviewed briefly. Methods are roughly classified into two categories according to their underlying purpose. One class of methods has the purpose of identifying patterns of dependence among the components of one variable Y via the indexing variables. This can be achieved by dimension reduction and graphical presentation. The other class of methods quantifying the linear relationship between one variable Y and other variables X, while accounting for the dependence among the components of Y. In both cases, the dependence patterns among the components of Y may be complicated and existing methods may not be suitable. I demonstrate existing methods are not able to capture fourth order dependence, which often is present in Type A and Type B data.A new statistical methodology, based on the Bayesian generalized bilinear mixed-effects model, is developed for Type A and Type B data. This model can be viewed as a tool for achieving the two desiderata for multivariate statistical methods described above: identifying and accounting for dependence. The model allows us to identify dependence patterns among the components of Y via a bilinear term, an inner product of two latent variables corresponding to two indexing variables. It is also suitable for studying the relationship between Y and X through a regression form while accounting for the dependence among the components of Y caused by repeated measures and/or unexplained fourth order dependence. A Markov chain Monte Carlo algorithm is described for Bayesian inference. Data from the 2012 summer Olympic games is analyzed to illustrate the model.The performance of the bilinear mixed-effects model-fitting algorithm is studied via the analysis of MCMC output arising from a series of simulation studies. The robustness of the methodology to model misspecification, particularly with respect to over-dispersion and the latent dimension of the bilinear random effects, are examined through these simulation studies.Affiliation networks are a particular type of Type A data, which record the relationship between a set of 'actors' and a set of 'events'. The generalized bilinear mixed-effects model considers the dependence patterns resulting from interactions between actors and events. In this setting, the model is used to explore patterns in extracurricular activity membership of students in a racially diverse high school in a Midwestern metropolitan area while controlling for differences in participation by both activity characteristics and attributes of the students. Using techniques from spatial point pattern analysis, we show how our model can provide insight into patterns of racial segregation in the voluntary extracurricular activity participation profiles of adolescents. In addition, household travel pat- terns are examined through latent variables associated with the geographic area of residence and the destination area of observed trips. In this case, the bilinear model highlights common travel behaviors of individuals residing inside the I-270 beltway of Columbus, OH.

Abstract: Chemical process engineering projects are complex and multi-disciplinary, requiring collaboration of different domains, such as business project management, chemical process, mechanical, electrical, and instrument with specific computer-aided tools. Current research on semantic interoperability is still domain specific. The lack of interoperability across domains remains a big issue in industry practice. The industrial demand for systematically managing the information generated throughout the lifecycle of engineering processes and associations across disciplines imposes a great research challenge. Rather than exchanging documents from one department to another, such as the chemical process department to the mechanical one, this research proposes an interdisciplinary engineering methodology based on a unified informatics approach to develop a systematic technology for supporting chemical process project lifecycle. Semantic characteristics of information entities and flows across chemical and mechanical engineering domains, and the implicit associations, are discussed. The similarity between the two disciplines inspires a unified engineering framework. Under this framework, two categories of new features that can be identified from commonly-observed chemical engineering processes, associative chemical process features and inter-domain functional features, are modeled. Related to those traditional product-related features in the mechanical engineering domain, the above two sets of features offer new mechanisms to support a multi-disciplinary and feature-based chemical process modeling system. Based on the proposed feature models, interdisciplinary engineering information association mechanisms are constructed. Such interdisciplinary engineering associations are explicitly expressed and systematically managed by constraint models. Hence, the feature associations are well-maintained along the project life cycle. A mechanism is then developed to dynamically construct feature parameter association map, which provides context association information among engineering entities. Based on the generated map, a well-controlled, incremental and dynamic engineering change propagation method is proposed to assist engineers with an intelligent change propagation solution. This proposed unified engineering methodology offers a solution of comprehensive and feature-based system modeling for real-world complex problems of system integration and interoperability, and hence, is capable of supporting engineering collaboration across disciplines. The insights gained by this research work also add to the growing understanding of relationships among engineering design in separate disciplines. Implementation of a prototype system based on feature definition and consistency maintenance mechanisms leads to a collaborative engineering platform for the chemical process design, which provides a feature-based modeling to explicitly represent characteristics of engineering significance as well as such associations. Thus information sharing is facilitated, while the feature models and constraints are all systematically managed. The prototype of applications of the proposed features shows the effectiveness towards consistency and efficiency improvement for chemical engineering informatics modeling. The mechanism proposed is capable of maintaining a consistent design through the life cycle of the chemical process project, and hence, the efficiency can be potentially improved by reducing the tedious revision work led by inconsistent design.

This research deals with Chinoiserie architecture in Germany during the eighteenth century and the early nineteenth century. The purpose of this research is not to describe the developmental process of this style in detail but to explore two different scopes of conducting historical research for historic architecture-a micro approach and a macro approach. The former approach focuses on individual buildings and describes their history by integrating written records and archaeological evidence, particularly the wood elements in the old structure. The latter approach takes a higher perspective and looks at the formation of the style, especially demonstrating the social dynamics that supported the movement of the ideas and objects. Taking the Chinese Tower in Donaustauf as an example, the first part of this work investigates the history of the Chinoiserie building with the help of two archaeological investigation techniques- wood anatomy and dendrochronology. It investigates its technical/design details and explains its construction history. The second part of this work seeks the reasons that Chinoiserie chose these design elements by examining its social context. Several studies by previous scholars have demonstrated the important role of the nobility in the diffusion of this pseudo-Chinese fashion. Using the methods of social network analysis, three factors are examined that may have influenced the choice of paradigms among the patrons of the buildings: iii geographical adjacency, personal contact, and kinship. The statistical results of the Quadratic Assignment Procedure (QAP) indicate that patrons' usage of paradigms is considerably correlated with their kinship, which improves our understanding of the significance of the genealogical relationship in influencing the taste in design and construction and the reception of foreign cultures. iv

This thesis investigates two systems in chip-based nonlinear optical microresonators. First is the generation of broadband frequency combs through parametric four-wave mixing and the associated phenomenon of cavity soliton formation in micro-resonators. We begin by investigating the relationship between cavity soliton based modelocking and traditional saturable absorber based modelocking. We find that a saturable absorber based modelocked laser with stimulated emission gain on only one cavity mode is dynamically equivalent to a parametrically driven cavity soliton comb. We also study the phase dynamics of the cavity soliton formation process for which we derive a set of phase equations from the governing Lugiato-Lefever equation which exhibit synchronization mechanisms akin to the Kuramoto model for coupled oscillators. These equations predict that phase anti-symmetrization preceeds phase synchronization in the cavity soliton formation process and explains the origin of the pump phase offset seen in parametrically driven cavity solitons. We then extend the concept of synchronization to systems of multiple cavity soliton frequency combs. We show that cavity solitons in evanescently coupled micro-resonators can synchronize to one another, generating synchronized pulses in the time domain and frequency locked combs lines in the spectral domain. Second is the demonstration of all-optical switching using nonlinear loss in micro-resonators. We achieve this through two means. The first is through the stimulated Raman response of silicon. Here we fabricate a silicon micro-ring that is co-resonant with both a pump field and the anti-Stokes field of the silicon material. The presence of the pump field stimulates optical loss at the antiStokes field, modulating the cavity resonance across all three regimes of coupling and demonstrating a single resonance all-optical switch. Secondly we use the two-photon absorption process of highly nonlinear organic dye molecules embedded in a polymer host. We achieve nonlinear loss induced decoupling of a cavity resonance of more than 7 dB and demonstrate the on-chip nonlinear loss of 18 cm/GW of the organic polymer.

Located in Central Asia, one of the most continental regions on Earth, the Tian Shan’s glaciers contribute critical fresh water to populated areas in the lowland. These glaciers are sensitive to climate change, and knowledge of contemporary glaciers and their changes in the past is of critical importance for sustainable development in this region. Constraining glacial fluctuations in recent centuries will fill a gap in numerical constraints on glacial history and paleoclimate information, and provide important evidence on the spatio-temporal changes of the climate systems in the Tian Shan. This doctoral dissertation investigates the timing and extent of Little Ice Age (LIA) glacial advances in the eastern Tian Shan. In particular, I conducted: 1) the mapping of glacial extents during the LIA and around 2010 using Google Earth high-resolution imagery and ArcGIS; 2) statistical analyses to examine relationships between local topographic/geometric factors and glacier change parameters; and 3) cosmogenic 10Be [beryllium 10] surface exposure dating of presumed LIA moraines. The major contributions of this dissertation include: 1) a total of 1173 contemporary glaciers with their corresponding presumed LIA extents were delineated in the eastern Tian Shan; 2) glacier area and mean elevation are the two major local factors that affect glacier area changes, but topographic/geometric factors cannot well explain changes in equilibrium line altitudes; 3) three major LIA advances occurred at 730±300 yr BP, 370±100 yr BP, and 210±50 yr BP were constrained based on 10Be surface exposure ages, and the maximum LIA extent (about 700–900 m beyond glacier termini) was reached asynchronously in different sub-regions; 4) presumed LIA moraines in front of small, thin glaciers yielded widely scattered and much older ages than LIA ages. The glacial deposits in front of such glaciers might have formed prior to the LIA and have been reworked during non-erosive glacial transport in LIA. This suggests that inheritance could be a more significant problem than degradation in the exposure age scatter of young glacial event. More dating work is needed to extend our knowledge on LIA glacial advances, and to better understand the influence of climate systems on glacier changes.

As a popular co-curricular activity, forensic participation is considered as an effective educational tool in sharping students’ logic thinking abilities (Allen & Berkowitz, 1999; Bellon, 2000; Lieberman, Trumble & Smith, 2000). However, in China, compared with the growing enthusiasm in debate among the Chinese students, research in this field is relatively thin. Therefore, in order to gain an in-depth understanding of how forensic participation influence students’ critical thinking abilities, I conducted this multiple case study which was grounded in the Paul-Elder Model of Critical Thinking. My respondents are three national or regional champions from a well-known forensic team in Eastern China. My major data collection include three one-on-one interviews with the respondents, some secondary interviews with their coach and teachers, observations on their debate training, and some online data such as the official blog of the team, my e-mail correspondence with the students and information culled from their personal social networking sites. My two research questions are “How does college students’ thinking change as a result of participating in forensics?” and “What features of forensic participation support students’ development of critical thinking?” In terms of research question one, I have found that first, as a result of forensic participation, my respondents’ questioning, critical reading, analyzing and evaluating skills have improved. Second, they developed some intellectual traits that are indispensable to their critical thinking abilities. Third, forensic participation has to some extent helped them to get rid of ego-centric and socio-centric thinking, which paved the way for them to become an accomplished and responsible thinker. As to research question two, I found that both the educational and epistemic features support students’ development of critical thinking. I also found out motivation plays such an important role in students’ critical thinking development that it could be added into the framework of Paul’s Model of critical thinking. My recommendations include improving the instruction methods in debate courses and enhance both the quantity and quality of the intercollegiate and national competitions.

A two-dimensional dynamic moving mesh algorithm is implemented for simulating aerodynamic oscillating airfoils. The airfoil is inserted into a uniform unstructured background mesh by exploiting an new technique named mesh rupturing, which allows for significant geometry movement without grid regeneration or interpolation between grids. Then unsteady flow simulation results are presented and validated by several test cases. Previous methodologies for unsteady flow simulation are listed and compared, advantages and disadvantages of the new mesh technique are discussed and advice for further research as well.