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China's cities continue to expand rapidly and under severe challenge of sustainable urban development. The Chinese Government has decided to bring agriculture back into the city in a state-controlled way and to re-educate urban residents to enjoy agriculture activities in urban areas. This research explores the Chinese Government's approach to new urban agriculture in China. It seeks to better understand and evaluate the impacts of multifunctional urban agriculture on sustainable urban development. The work is set within the context of China's extremely rapid urbanization and concerns about pollution, poor lifestyles and an over-emphasis on manufacturing as the economic driver of growth. This thesis has presented a first attempt to redefine the term 'urban' in relation to urban agriculture, extending it to the urban core areas, desakota areas and exurban areas. In this way it suggests a new typology of urban agriculture in China, with a potentially broader range of objectives and possibilities that might normally be associated with the subject or practice. Taking Beijing as the case study city, this study selects 3 of its 16 districts: Chaoyang, Changping and Miyun representing core, desakota and exurban areas. The specific projects in these three districts are totally different, and together they represent the three levels in the model of Chinese new urban agriculture. Each level of model is informed and supported by case study of practical projects. These are: Government fully-owned large projects, Government-supported privately run projects and Folk Custom Villages. Data was collected from direct observation, documentation, archive, physical survey, interviews and questionnaires. This thesis found that the "Chinese" urban agriculture model, through three different types of projects, aims to make people rethink the role of agriculture and see it not simply as something undertaken by others in a rural area, nor as something simply to provide food. Rather, it can be something which enhances the urban experience, improves the urban environment, offers leisure facilities, engages people in traditional culture and provides a diverse range of employment and livelihood activities. A well planned modern agricultural production is required to create an agricultural environment with reasonable spatial layout to reduce pollution and to create aesthetically pleasing and sustainable landscapes. It can help urban agriculture ii integrate into the city system in a more sustainable way by reconnecting urban life and rural culture. This model, therefore, sets urban agriculture in a central role within planned urbanization. In summary, this thesis suggests that this model could become an important strategy for land use planning, urbanization and the sustainable development of Chinese cities, indeed, all cities, in the future. This study will be of interest to those scholars who are seeking to explore the Chinese urban agriculture as an effective method for land use in sustainable urban development.

5G-and-beyond communication systems are expected to be in a heterogeneous form of multiple-antenna cellular base stations (BSs) overlaid with small cells. The fully-digital BS structures can incur significant power consumption and hardware complexity. Moreover, the wireless BSs for small cells usually have strict size constraints, which incur additional hardware effects such as mutual coupling (MC). Consequently, the transmission techniques designed for future wireless communication systems should respect the hardware structures at the BSs. For this reason, in this thesis we extend generic downlink precoding to more advanced hardware-informed transmission techniques for a variety of BS structures. This thesis firstly extends the vector perturbation (VP) precoding to multiple-modulation scenarios, where existing VP-based techniques are sub-optimal. Subsequently, this thesis focuses on the downlink transmission designs for hardware effects in the form of MC, limited number of radio frequency (RF) chains, and low-precision digital-to-analog converters (DACs). For these scenarios, existing precoding techniques are either sub-optimal or not directly applicable due to the specific hardware constraints. In this context, this thesis first proposes analog-digital (AD) precoding methods for MC exploitation in compact single-user multiple-antenna systems with the concept of constructive interference, and further extends the idea of MC exploitation to multi-user scenarios with a joint optimisation on the precoding matrix and the mutual coupling effect. We further consider precoding for wireless BSs with a limited number of RF chains, in the form of compact parasitic antenna array as well as hybrid analog-digital structures designed for large-scale multiple-antenna systems. In addition, with a reformulation of the constructive interference, this thesis also considers the low-complexity precoding design for the use of low-resolution DACs for a massive-antenna array at the BSs. Analytical and numerical results reveal an improved performance of the proposed techniques compared to the state-of-the-art approaches, which validates the effectiveness of the introduced methods.

Marine hydrates, which lock-up vast quantities of methane, are considered to be a prospective alternative energy source, a slow tipping point in the global carbon cycle and a probable trigger for submarine failures. In this thesis marine hydrate systems offshore of Mauritania and associated structural and sedimentary features are investigated by utilising two surveys of high-quality three-dimensional (3-D) seismic data. Interpreting them provides new insights into marine hydrate systems and how they respond to changes in ambient conditions. In one region of one of the 3-D seismic surveys, a shear zone covering 50 km2 is identified immediately above the hydrate bottom simulating reflector (BSR). It is considered to be the initial stages of a failure that did not result in widescale downslope transport of the succession. Due to this failure not going to completion, some free gas remains trapped at the level of the BSR. At this level the presence of free gases is supported by the continuous high-amplitude reflections. It is proposed that buoyancy built up by the inter-connected gas accumulation increases the pore pressure of the overlying hydrate-bearing to the level such that its base was critically stressed. In this research there is no seismic evidence for failures triggered by hydrate dissociation but the role of free gas in priming submarine failures is examined. Whether marine hydrates can release significant amounts of methane into the atmosphere is inconclusive. In this research a proposed model indicates that methane was re-captured in the hydrate stability zone after being liberated. Ocean warming since the last glacial maximum (LGM) gave rise to the shoaling of the base of the hydrate stability zone (HSZ). Gases released from hydrate accumulating at the base entered the HSZ, driven by buoyancy built up in the gas accumulation. The hydrate seal was breached and this is manifested by 15 gas chimneys in seismic data. Hydrates then re-formed at a specific level within the HSZ. This study implies that not all of methane would enter the ocean after released from hydrates and therefore the contribution of marine hydrates to the atmospheric methane budget may be not that much as it was predicted before. Gas venting is an effective way to transport methane at depth vertically to the ocean and an example of it is found in the feather edge of marine hydrate. This venting was possible due to the presence of faults above a salt diapir and is manifested by a series of pockmarks and mounds at the seabed. The BSR at this site is convex upwards and hence formed a trapping geometry for underlying free gases. Numerical model shows that this up-convex geometry is caused by the salt diapir having a higher thermal conductivity. Permeable migration conduits along the faults and excess pore pressure at the top of the trap allow for the happening of the venting. Compared with the neighbouring area where the BSR can be well observed, the region affected by diapirism has a limited scale of the observable BSR. This absence is proposed to result from the formed trap intercepting methane-rich pore fluid that would migrate landwards along the level of the base of the HSZ.

The rational operator-based approach to depth from defocus (DfD) using pill-box point spread function (PSF) enables texture-invariant 3-dimensional (3D) surface reconstructions. However, pill-box PSF produces errors when the amount of lens diffraction and aberrations varies. This thesis proposes two DfD methods, one using the Gaussian PSF that addresses the situation when diffraction and aberrations are dominant, and the second based on the generalised Gaussian PSF that deals with any levels of the problem. The accuracy of DfD can be severely reduced by elliptical lens distortion. This thesis also presents two correction methods, correction by distortion cancellation and correction by least squares fit. Each method is followed by a smoothing algorithm to address the low-texture problem of DfD. Most existing human activity recognition systems pay little attention to an effective way to obtain training silhouettes. This thesis presents an algorithm to obtain silhouettes from any view using 3D data produced by Vicon Nexus. Existing background subtraction algorithms produce moving shadow that has a significant impact on silhouette-based recognition system. Shadow removal methods based on colour and texture fail when the surrounding background has similar colour or texture. This thesis proposes an algorithm based on known position of the sun to remove shadow in outdoor environment, which is able to remove essential part of the shadow to suffice recognition purpose. Unlike most recognition systems that are either speed-variant, temporal-order-variant, inefficient or computational expensive, this thesis presents a near real-time system based on embedded silhouettes. Silhouettes are first embedded with isometric feature mapping, and the transformation is learned by radial basis function. Complex human activities are then learnt with spatial objects created from the patterns of embedded silhouettes.

Cell migration and invasion is a central process in embryonic development, wound healing and immune responses. Errors during this process have serious consequences, including mental retardation, vascular disease, tumor formation and metastasis. An understanding of the mechanism by which cells migrate and invade may lead to the development of novel therapeutic strategies for controlling, for example, cancer metastasis. Fascin is an actin-bundling protein involved in filopodia assembly and cancer invasion and metastasis of multiple epithelial cancer types. In this thesis, I have investigated the role of fascin in invadopodia formation, which are invasive finger-like protrusions that cancer cells use to invade into and degrade extracellular matrix. I demonstrated that fascin and its actin bundling activity are required for the assembly of the actin cytoskeleton at invadopodia as well as for the degradation of matrix. Fascin is a very stable component of invadopodia and its presence enhance the stability of actin structures at invadopodia. Furthermore, fascin is required for invasive migration into collagen I-Matrigel gels particularly in cell types that use an elongated mesenchymal type of motility in 3D. These data provide a potential molecular mechanism for how fascin increases the invasiveness of cancer cells. During embryogenesis, melanoblasts proliferate and migrate ventrally through the developing dermis and epidermis as single cells. In the second part of this thesis, I examined the importance of small Rho GTPase Rac1 on melanoblast migration during development. I demonstrate that targeted deletion of Rac1 in the melanoblasts of developing mice causes defects in migration, cell cycle progression and cytokinesis. Rac1 null cells migrate markedly less efficiently, but surprisingly global steering, crossing the dermal/epidermal junction andhoming to hair follicles are normal. Melanoblasts navigate in the epidermis using two classes of protrusion: short stubs and long pseudopods. Short stubs are driven by actin assembly, but unexpectedly are independent of Rac1, Arp2/3 complex, myosin or microtubules. Rac1 positively regulates the frequency of initiation of long pseudopods, which promote migration speed and directional flexibility. Scar/WAVE and Arp2/3 complex drive actin assembly for long pseudopod extension, which is also microtubule dependent. Myosin contractility balances the extension of long pseudopods by effecting retraction and allowing force generation for movement through the complex 3D epidermal environment. In addition, I demonstrated that expression of activated N-Ras did not affect migration and proliferation of melanoblast during embryogensis. However, Rac1 is required for constitutively active N- Ras induced dermal melanocytes survival in mice.

People have traditionally relied on mass media to seek updated information about breaking news events by turning on TV, listening to radio, or checking newspaper. Nowadays with the advantage of social technologies, there has been a significant shift in ways that people gather and communicate news, and increasingly user-generated content in social media has become an important source of news. Prior literature has studied the news reporting process in conventional mass media, and found that gatekeepers play an important role in the process. Traditionally, gatekeepers are newsrooms editors or journalists who control the information through selecting, filtering or crafting what gets published to the public, and thus they have a unique power in spreading of information and influencing audience’ perspective. In contrast, the process of how user-generated content are created by contributors in social media platforms is different in terms of who are able to contribute, and what is the collaboration process of creation. Specifically, user-generated content in social media is usually free to be created or edited by almost anyone. Moreover, many social media platforms such as Wikipedia enable collaboration among contributors, which can facilitate and allow collective determination of what content is presented to the public. At the same time, although everyone can contribute to social media, a majority of users on social media platforms only act as passive information consumers. In practice, not everyone and not every perspective is represented equally -- there are still certain users who are more powerful in determining the content that the general audience read in social media. In fact, there are social media contributors who play the role similar as gatekeepers in traditional mass media. However, there is a little knowledge about who social media gatekeepers are, how to identify them, and most importantly how do they impact news content production and dissemination. My PhD dissertation aims to answer these questions, and I intend to uncover the gatekeeping process in social media around news events across two different social media platforms: Twitter and Wikipedia. Each of these platforms represent a different degree of collaboration process, moderation process, and different community norms. I first propose an actionable definition of social media gatekeepers backed by literature on news reporting in social media and traditional mass media. I then present two case studies of identifying and understanding gatekeepers on both Twitter and Wikipedia at scale. The results of my mixed research approach highlight that, unlike the general users, social media gatekeepers are often self-determining citizen journalists who manage their media presentation strategically. The results also demonstrate that gatekeepers tend to exhibit behavior mostly in accordance with the journalism norms: they contribute to and guard the quality of the user-generated content. Moreover, the results also highlights the role of collaboration in the gatekeeping process: gatekeepers' effects in improving the quality of user-generated content rely on the collaboration among gatekeepers themselves as well as other users. My dissertation presents the first piece of research on quantitatively identifying social media gatekeepers on a relatively large scale as well as examining their impact on news sharing and production.

My thesis work consists of two main projects with some connections. In the first project we establish a v1 periodicity theorem in Ext over the complex motivic Steenrod algebra. The element h1 of Ext, which detects the homotopy class \eta in the motivic Adams spectral sequence, is non-nilpotent and therefore generates h1-towers. Our result is that, apart from these h1-towers, v1 periodicity operators give isomorphisms in a range near the top of the Adams chart. This result generalizes well-known classical behavior. In the second project we consider a nontrivial action of C2 on the type 1 spectrum Y, which is well-known for admitting a v1-selfmap. The resultant finite C2-equivariant spectrum can also be viewed as the complex points of a finite real motivic spectrum. We show that one of the $v1-selfmaps of Y can be lifted to a selfmap in the real motivic case. Further, the cofiber of the real motivic selfmap is a realization of the subalgebra AR(1) of the real motivic Steenrod algebra. The finite subalgebra AR(1), generated by Sq1 and Sq2, of the real motivic Steenrod algebra AR can be given 128 different AR-module structures. We also show that all of these AR-modules can be realized as the cohomology of a 2-local finite real motivic spectrum. The realization results are obtained using an real motivic analogue of the Toda realization theorem. We notice that each realization of AR(1) can be expressed as a cofiber of a real motivic v1-selfmap. The C2-equivariant analogue of the above results then follows because of the Betti realization functor. We identify a relationship between the RO(C2)-graded Steenrod operations on a C2-equivariant space and the classical Steenrod operations on both its underlying space and its fixed-points. The second project is joint work with Prasit Bhattacharya and Bertrand Guillou.

Cardiac muscle contraction and relaxation is controlled by changes in intracellular Ca2+, indicating that Ca2+ transport is a fundamental regulator of proper muscle function in the heart. The primary cardiac Ca2+ transporter is the sarcoendoplasmic reticulum Ca-ATPase 2a (SERCA2a), a transmembrane protein pump embedded in the sarcoplasmic reticulum (SR). SERCA2a pumps cytosolic Ca2+ into the sarcoplasmic reticulum (SR) of cardiac myocytes, enabling muscle relaxation during diastole. Abnormally high cytosolic [Ca2+] is a central factor in heart failure, suggesting that augmentation of SERCA2a Ca2+ transport activity could be a promising therapeutic approach. SERCA2a is inhibited by the protein phospholamban (PLB), and a novel transmembrane peptide, dwarf open reading frame (DWORF), is proposed to enhance SR Ca2+ uptake and myocyte contractility by displacing PLB from binding to SERCA2a. However, establishing DWORF’s precise physiological role requires further investigation. The work presented in this thesis focuses on the mechanisms and structural basis of SERCA2a regulation and primary drug screening of SERCA2a. In the first study (Chapter 4), we developed cell-based FRET biosensor systems that can report on protein-protein interactions and structural changes in SERCA2a complexes with PLB and/or DWORF. To test the hypothesis that DWORF competes with PLB to occupy the SERCA2a binding site, we transiently transfected DWORF into a stable HEK cell line expressing SERCA2a labeled with a FRET donor and PLB labeled with a FRET acceptor. We observed a significant decrease in FRET efficiency, consistent with a decrease in the fraction of SERCA2a bound to PLB. Surprisingly, we also found that DWORF also activates SERCA’s enzymatic activity directly in the absence of PLB at sub saturating calcium levels. Using site-directed mutagenesis, we generated DWORF variants that do not activate SERCA, thus identifying residues P15 and W22 as necessary for functional SERCA2a-DWORF interactions. This work advances our mechanistic understanding of the regulation of SERCA2a by small transmembrane proteins and sets the stage for future therapeutic development in heart failure research. In the second study (Chapter 5), we have developed fluorescence resonance energy transfer (FRET) biosensors with red-shifted fluorescent proteins, yielding improved characteristics for time-resolved (lifetime) fluorescence measurements. In comparison to biosensors with green and red FRET pairs (GFP/RFP), fluorescent proteins that emit at longer wavelengths (orange and maroon, OFP/MFP) increased the FRET efficiency, dynamic range, and signal-to-background of high-throughput screening (HTS). This combination promises to revolutionize high-precision FRET measurements from living-cells for the discovery of urgently needed therapeutics.

Engineers have been exploiting many technologies and advanced materials to reduce the weight of automobile body structures without sacrificing crash safety when designing automobile frames. One of the most critical automotive body components is the frame that supports a hood as it protects occupants and pedestrians in various ways. Hoods are designed to withstand many static, dynamic and local impact loads. This thesis considers the design of hoods under static loads while minimizing weight and maximizing stiffness. This thesis continues previous work in which automated methods were developed to generate a large variety of hood frame designs (CAD models). Ten hood skins were combined with 11 frame feature patterns to get 110 shape variants. Each hood shape variant was then given 100 size variants, resulting in a geometry data set of around 11000 data points in total. Static Finite Element Analysis (FEA) was done on all these shape and size hood models. Using this data set, the goal of this thesis was to investigate alternative methods for optimizing hood frames with the objective of maximizing stiffness. After the parametric sensitivity study, input size parameters were reduced to five for each hood model. With these reduced parameter sets, three methods were considered. The first method is Skin-by-Skin Analysis (Method 1), in which the FE results (max deflection) were partitioned by the skin. Thus, each subset had 10 frame shapes combined with 100 size variants. An ordered Table was constructed to determine the most dominant feature pattern for each skin, regardless of size parameters. This method showed that five out of ten skins have the so-called PTRN 6 as the best. The second method is General Feature Patterns Analysis (Method 2). This method was to find a pocket pattern that has the most dominant performance across all skins. Because skins are different in area, a normalized deflection value was used as a Measure of Goodness. The result of this method shows that the PTRN 6 is the optimal result regardless of skin. In some ways, we could say that these two methods are somewhat consistent. The third method is Non-uniform parameters Analysis (Method 3). Each skin and pocket pattern were characterized by a common parameter set, which was considered as input factors in DOE, while a normalized stiffness was used as the output variable. To reduce the complexity, the parametric sensitivity study was done again, and to improve the accuracy, the Response Surface Method (RSM) and the optimization that is based on the result of RSM were used. The result of the third method is that the PTRN 4 pocket pattern is the optimal result. It is acceptable that the results of Method 3 are different from the result in Method 1 and 2 because the input parameters are different, which means that these methods are different from conventional DOE which only operates on uniform variable sets. But different hood frames cannot be described entirely by size variants of the same topology. The original contribution of this thesis is the development of optimization methods for a mix of different topologies combined with size variants. Also, this study does comparisons of all three methods.

The unit selection problem aims to identify a set of individuals who are most likely to exhibit a desired mode of behavior, which is defined in counterfactual terms. A typical example is that of selecting individuals who would respond one way if encouraged and a different way if not encouraged. Unlike previous works on this problem, which rely on ad-hoc heuristics, we approach this problem formally, using counterfactual logic, to properly capture the nature of the desired behavior. This formalism enables us to derive an informative selection criterion which integrates experimental and observational data. We show that a more accurate selection criterion can be achieved when structural information is available in the form of a causal diagram. We further discuss data availability issue regarding the derivation of the selection criterion without the observational or experimental data. We demonstrate the superiority of this criterion over A/B-test-based approaches.

The dissertation consists of three chapters spanning two areas of finance: corporate finance and institutional investors. In the first chapter, “Board Gender Diversity, Firm Culture, and Female Inventors”, I study how employee's Research and Development (R&D) activity is affected by firm culture. Using board gender diversity as a proxy for female-friendly culture, I find that a greater representation of women in the boardroom is associated with increased productivity and innovation output by female inventors relative to male inventors. Female inventors file more highly cited patents and less uncited patents. The effect is driven by female directors with R&D or high-tech expertise. The results support the notion that women in leadership positions cultivate a more female-friendly firm culture. In the second chapter, “Mutual Fund Preference for Pure-Play Firms” coauthored with Bradford Jordan and Mark Liu, we examine how a firm’s organization form affects mutual fund investments. We show that actively managed mutual funds avoid diluting their industry expertise by holding more pure-play firms. Specifically, mutual funds prefer firms that operate in fewer industries and firms with higher industry beta; this preference is stronger among mutual funds with greater industry expertise. We propose a measure, Pureplayness, as the fraction of a fund's equity invested in pure-play firms. Our results suggest that funds with higher Pureplayness have better risk-adjusted performance. In the third chapter, “Can Mergers and Acquisitions Internalize Positive Externalities in Funding Innovation” coauthored with Thomas Chemmanur and Mark Liu, we find that mergers and acquisitions between innovation users and innovation producers enhance innovation output. The combined firm can share the upfront costs and better appropriate the benefits associated with the innovation.

Abstract: Impure gas flooding can be used as an effective method for enhancing oil recovery. The minimum miscibility pressure (MMP) is a key parameter in the design of impure gas injection. It is thus of great importance to accurately determine the MMP for the impure gas injection process. This study experimentally determines the MMP between CO2-CH4 mixtures and a crude oil; slim-tube experiments have been conducted to measure the MMPs between this light oil sample and CO2-CH4 mixtures with different CH4 contents. At CH4’s molar fractions of 0 mol%, 5 mol%, 10 mol%, 20 mol% and 100 mol%, the corresponding MMPs are measured to be 17.74 MPa, 19.84 MPa, 22.79 MPa, 27.05 MPa and 58.64 MPa, respectively. The experimental results show that increasing the amount of CH4 present in the mixture can increase the MMP between injection gas and crude oil. When CH4’s molar fractions are 5 mol%, 10 mol% and 20 mol%, Dong (1999) correlation yields absolute relative deviations (ARD%) of 0.00% and 2.98%, and 0.70%, respectively, for the MMP predictions; these errors are lower than those yielded by the other correlations (Kovarik, 1985; Sebastian et al., 1985; Alston et al., 1985; Emera and Sarma, 2006; Shokir, 2007). For the crude oil examined in this study, Dong (1999) correlation provides the most accurate prediction of CO2-CH4 (with CH4 content up to 20 mol%) MMP among all the impure-CO2 MMP correlations examined.

Today, we are living in environments that are full of cameras embedded in devices such as smart phones and wearables. These mobile devices and as well as apps installed on them are designed to be extremely convenient for users to take, store and share photos. In spite of the convenience brought by ubiquitous cameras, users' privacy may be breached through photos that are taken and stored with mobile devices. For example, when users take a photo of a scenery, a building or a target person, a stranger may also be unintentionally captured in the photo. Such photos expose the location and activity of strangers, and hence may breach their privacy. In addition, photos that are stored on smartphones may contain private information (e.g., driver's license) about phone owners, which raise people’s privacy concerns over unauthorized access by installed apps. The goal of this dissertation is to protect people's privacy in photo taking and accessing. To achieve this goal, we propose several systems to address the aforementioned privacy issues. To protect stranger's privacy in photo taking, we proposed two systems called PrivacyCamera and PoliteCamera. Through cooperation between the photographer and the stranger, these systems can automatically blur the stranger’s face in the photo upon the stranger’s request when the photo is being taken. Even though PrivacyCamera and PoliteCamera can successfully protect stranger's privacy, they depend on the cooperation between the photographer and the stranger. That requires both the photographer and stranger to install the proposed systems on their mobile phones; however, this is not always possible. Therefore, we further propose a feature-based model to automatically distinguish the target from strangers in a photo, so that we can blur all strangers' faces without the cooperation. Finally, we designed PhotoSafer, a content-based and context-aware to protect private photos from unauthorized access on Android phones. In future work, we plan to design a privacy-preserving online sharing system, which has less burden of policy settings and can protect the privacy of strangers in a photo. In addition, we will also consider designing personalized systems to protect user-specific private photos.

Sepsis is a high mortality syndrome characterized by organ dysfunction due to a severe and dysregulated acute inflammatory response to infection. Research into therapies for this syndrome has historically ended in failure, which has largely been attributed to the elevated levels of subject heterogeneity. What may have been previously attributed to variability in sepsis may be due to mechanistic differences between patients. Endotypes are distinct subtypes of disease, where underlying causes such as mechanistic or pathway related differences manifest into phenotypes of disease. The lack of mechanistic understanding of immune mediator dynamics and the responses they trigger necessitates a mathematical modeling approach to analyze its complexities. A transfer function model is proposed to describe and cluster the dynamics of key inflammatory mediators. Five sepsis endotypes were discovered and revealed motifs of overwhelming inflammation, various levels of immunosuppression, sustained inflammation, and immunodeficiency. An accurate clinical tool was proposed to classify subjects into endotypes using six-hour trajectories of clinical data. A physiological ordinary differential equation model of sepsis is proposed that characterizes the interactions of inflammatory signaling molecules, neutrophils, and macrophages across the bone, blood, and tissue compartments of the body. This model used to generate individual subject fits against human sepsis data. Population-level parameter analysis implicated macrophage cell death and cytokine half- dynamics in endotype-level differences. Several proof-of-concept statistical models were introduced to demonstrate that it is possible to estimate the pre-hospital time of sepsis subjects and to quantify their sepsis-induced systemic tissue damage. A nearest-neighbor-based method was verified against animal and human data and revealed that identifying infection time-zero of sepsis patients can be quickly estimated with high accuracy using commonly measured clinical features. A logistic regression ensemble model demonstrated revealed early organ dysfunction were significant contributors to systemic damage and mortality. Knowledge of time-zero and systemic damage levels, in combination with an endotype classifier, provides clinicians with a clear depiction of where a subject is located on their sepsis trajectory. Such a decision support system enables therapy timing, early organ support, and targeted therapies to guide personalized treatment and shift patients towards better outcomes in sepsis.

The camp experience has been an important part of children's lives for over 150 years. Unfortunately, insight from parents about opportunities for youth growth and development has not been systematically documented. Rather, more research exists concerning the value and benefits of camp experience from the perspective of camp staff and camper. PEAK (Playful Education & Adventure for Kids) Camp is accredited by American Camp Association, and it was in its 14th years in 2014. There has been no documented research about a PEAK Camp outcome study. The purpose of this study is to examine parents' perception of their children's summer camp experience in relation to attributes of youth development. This study utilized an online pre-test and post-test questionnaire to survey the PEAK Summer Camp 2014 parents' perception to measure outcomes in six areas: Friendship Skills, Independence, Teamwork, Perceived Competence, Responsibility, and Problem-Solving Confidence.

This paper illustrates how to use the comprehensive legible cityscape plan to revitalize a small city. The study is in Wilmington, Ohio. In the past two decades, especially in United States, lots of small cities are facing challenges, such as absorption by metropolitan cities, declining population, loss of working lands, lack of job opportunities and inactive commercial. How to solve these problems becomes one of the most important challenges for our society. By the methods of site research and analysis mapping, a comprehensive legible cityscape plan is developed. The comprehensive legible cityscape plan in this project consists of: retail store sign design, creating sense of entrance, wayfinding signs, creating or redesigning open space, main intersection redesign, bike lane and detail design, factory redesign and wall printing. The comprehensive legible cityscape plan will make the city of Wilmington more walkable, livable and legible. Moreover, it will bring back more residents, attract more visitors and create more job opportunities. As a conclusion, the comprehensive plan makes the city more legible, and revitalizing a small city reduces pressure on large cities and makes a better livable place for local residents.

This work presents various engineering efforts in improving the performance of Cr:Znse (Chromium-doped Zinc Selenide) solid-state lasers. Prior study has shown that this laser material (Cr:ZnSe) is promising for demonstrating selfsimilar pulses due to its high gain and nonlinearity. However, it suffers from strong thermal lensing effect, which is the main obstacle for power scaling. In Chapter 2, production process of Cr:ZnSe including thermal diffusion doping, dicing and polishing is covered with detail. Numerical simulation is presented in Chapter 3 to describe the physical nature of the thermal lensing. A costeffective scheme of anti-reflective coating of the ZnSe is detailed in Chapter 4. And lastly, the performance of our Cr:ZnSe laser with the developed antireflective coating is evaluated and the experimental observations are discussed.

This dissertation proposes a closed-loop control system model to facilitate mathematical analysis and promote operational efficiency of the dynamic bidding process. Electricity market deregulation has brought an innovation of the market structure and changed the electric power production from the old monopolistic way to a competitive market environment. Electricity is treated as a commodity and being traded among the market participants. The analysis of electricity market behavior becomes increasingly important and challenging. This dissertation develops a control-theoretic model to analyze and predict electricity market behavior. The model is based on the perspective of the power generation side (GENCOS) and ISO. The purpose is to achieve a rational profit maximizing behavior for GENCOS during the day-ahead bidding process and to improve the wholesale market efficiency. The control-theoretic model uses the game theory embedded with the learning ability as the major bidding strategy, which allows GENCOS to adjust their next-day bidding in the form of supply function equilibrium (SFE) through market observations. Recursive least square (RLS) method based on two ARMA models is introduced for demand and price forecasting in order to maximize the GENCO’s profit. This method is implemented into the bidding strategy of SFE with learning process. In order to better capture the demand and price dynamics beforehand, this dissertation also introduces an adaptive multiresolution prediction algorithm. This algorithm establishes a systematic structure to hierarchically decompose the original demand and price data into subtasks with different time frames, within which the data are able to be trained separately and efficiently. The real market data from New York Independent System Operator and PJM interconnection are used to demonstrate the effectiveness of the proposed model and training algorithm.

Leaf and fine root litter decomposition is central to biogeochemical cycles in northern forest. I studied the nitrogen translocation to leaf litter during decomposition, and the fine root decomposition process. Nitrogen immobilization in fresh litter represents a significant N flux in forest ecosystems, yet its sources, controls, and implications are not well studied. I conducted two leaf decay experiments, using 15N-labeled sugar maple leaf litter, to quantify N transport from old litter and soil to fresh litter during early stages of decomposition, and I examined the influence of litter N concentration and soil N availability on upward N transfer in a northern hardwood forest. After one year of decay, the average N transfer from soil to fresh litter (2.63 mg N g-1 litter) was much higher than the N transfer from older litter (1 to 2 yr old) to fresh litter (0.37 mg N g-1 litter). As an indicator of N transfer efficiency from these N sources into decaying litter, we calculated the ratio of annual N transfer / excess 15N pool for these two N sources. The ratio was not significantly different between old litter and soil, suggesting that fungi utilize N in the old litter and mineral soil pools for transport to decaying fresh litter with similar effectiveness. Litter N concentration had a significant effect on upward N flux into decaying leaf litter, whereas no effect of soil N fertilization was observed. These results illustrate the mechanisms whereby continuing N deposition will affect the important process of N translocation into decaying litter. Future work characterizing the fungal taxa involved in this process and their responses to changing environments is needed. fine root decomposition. Another of my studies is on Despite its importance in global biogeochemical cycling, fine root decomposition has received limited attention, and factors that regulate this process are not well understood. Most studies on fine root decomposition have been based on litterbag experiments, but the appropriateness of this approach has been questioned. In this study, I compared fine root decay using litterbag and intact core approaches, and I evaluated the role of fungal hyphal networks, root chemistry, and soil environment in regulating root decay rates and decomposer communities. I used 454 pyrosequencing to survey and compare the fungal communities on decaying fine roots from different samples. The results show that 1) fine roots decaying in intact cores have a significantly higher rate of mass loss and N, P release than fine roots decaying in litterbags; 2) there is an obvious difference between fungal communities developed on intact core root samples and those on litterbag root samples; 3) by rotating intact cores and disrupting the formation of fungal hyphal networks, fungal decomposer communities on fine roots were altered, yet the decay rates of fine roots did not change and; 4) root chemistry, rather than soil environment, has a significant effect on fine root decomposition rate. NCBI BLAST search of the most abundant fungal operational taxonomic units in this study found ectomycorrhizal fungi orders such as Boletales, Thelephorales, and Cantharellales on roots after half year and one year of decay, suggesting that ectomycorrhizal fungi may become saprotrophic after root senescence. Further phylogenetic analysis is needed to identify the important fungal species that are involved in fine root decomposition, which will shed further light on the controls of the fine root decay process.

Linearly solvable Markov Decision Process (MDP) models are a powerful subclass of problems with a simple structure that allow the policy to be written directly in terms of the uncontrolled (passive) dynamics of the environment and the goals of the agent. However, there have been no learning algorithms for this class of models. In this research, inspired by Todorov’s way of computing optimal action, we showed how to construct passive dynamics from any transition matrix, use Bayesian updating to estimate the model parameters and apply approximate and efficient Bayesian exploration to speed learning. In addition, the computational cost of learning was reduced using intermittent Bayesian updating reducing the frequency of solving the Bellman equation (either the normal form or Todorov’s form). We also gave a polynomial theoretical time complexity bound for the convergence of the learning process of our new algorithm, and applied this directly to a linear time bound for the subclass of the reinforcement learning (RL) problem via MDP models with the property that the transition error depends only on the agent itself. Test results for our algorithm in a grid world were presented, comparing our algorithm with the BEB algorithm. The results showed that our algorithm learned more than the BEB algorithm without losing convergence speed, so that the advantage of our algorithm increased as the environment got more complex. We also showed that our algorithm’s performance is more stable after convergence.

The objective of this study is to investigate the Model predictive control (MPC) strategy, analyze and compare the control effects with Proportional-Integral-Derivative (PID) control strategy in maintaining a water level system. An advanced control method, MPC has been widely used and well received in a wide variety of applications in process control, it utilizes an explicit process model to predict the future response of a process and solve an optimal control problem with a finite horizon at each sampling instant. In this thesis, we first designed and built up a closed-loop two-tank water level system. Next, we modeled the system and linearized the model for simplification in the analysis and design. Then, we implemented the model in a simulation environment based on Matlab. We tried both MPC and PID control methods to design the controller for the two-tank system, and compared the results in terms of settling time, overshoot, and steady-state error under various operational conditions including time delays. The results showed the advantage of MPC for dealing with the system dynamic over PID and could be designed for more complex and fast system dynamics even in presence of constraints.