Theses and Dissertations from UMD
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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item "I'm not alone in this": Co-managing stigmatized chronic health conditions(2021) Chopra, Shaan; Choe, Eun Kyoung; Library & Information Services; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)People living with chronic health conditions often have to take care of multiple medical, logistical, and everyday tasks, including monitoring symptoms, following treatments, going for appointments, as well as managing work, familial, and social obligations. Unlike shorter illnesses, chronic health conditions are lifelong, often requiring constant monitoring and management, and as such, it is challenging for the individual to manage their daily life alongside their health, all by themselves. Further, people often experience stigma around their self-image and abilities due to their chronic conditions, further making acceptance of and life with the condition challenging. In this work, I look into how people living with chronic health conditions informally share the responsibility of managing their health and affected daily life activities with people in their close circle. I conducted in-depth interviews with 16 people living with chronic health conditions who collaboratively manage (or "co-manage") at least some aspects of their health with people in their close circles. I report on their (a) current co-management practices, including their use of technology to facilitate the same, and (b) experiences with stigma and its impacts on disclosure, support-seeking, and communication around their health, in different environments. I found that people appropriated different tools and technologies to monitor, coordinate, and collaborate with their co-managers. The nature of their relationship with co-managers and the physical or virtual space within which they co-managed were also key in shaping their current practices. I further identified avenues for designing technology to support people's diverse co-management needs, such as collaborative tracking, shared-space coordination, and navigating stigma during disclosure and support-seeking, contributing to HCI literature on designing for stigmatized health topics, chronic health management, and collaborative care.Item Essays on Labor Markets and Agriculture in Developing Countries(2020) AFLAGAH, Fo Kodjo Dzinyefa; Goldberg, Jessica; Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation studies topics related to labor markets and agricultural cooperatives in developing countries. In the first chapter, I study the Employment Tax Incentive (ETI), a South African wage subsidy to firms for newly hired young workers. This chapter provides a unique contribution to the literature on the effects of wage subsidies in developing countries. The ETI is one of only a few nationally implemented wage subsidies. Additionally, South Africa has the highest youth unemployment rate in the world. I use a difference-in-difference strategy based on age-eligibility and the start date of the policy to estimate its effects on youth employment outcomes in the first year of implementation. I find that even though the take-up rate of subsidies by firms was higher than expected, youth employment did not improve. I discuss the potential structural factors responsible for the seeming failure of this policy. In the second chapter, I explore the importance of ethnic capital, a proxy for social capital, in determining labor market outcomes for South Africa’s internal migrants. While the role of social networks for the labor market outcomes of international migrants has been extensively studied, internal migrants have not received the same attention. Arguably, internal migration is an important phenomenon for developing countries. I look at how ethnic capital affects the employment probability and the occupation choice of South African internal migrants. I find that the employment probability of an internal migrant is driven by the education distribution of his ethnic group, even after accounting for local labor market conditions and unobserved ethnic group effects. I also find that occupation choice is related to the education distribution and the gender composition of the ethnic group at the destination. In the third chapter, coauthored with Angelino Viceisza and Tanguy Bernard, we study how communication can be improved to solve coordination issues within agricultural cooperatives, using both a lab-in-the-field experiment (LFE) and a randomized controlled trial (RCT). Theory and conventional lab experiments suggest that non-binding pre-play communication can enhance coordination of interdependent agents in situations of strategic uncertainty, and that coordination should be easier to achieve in smaller groups. We test for these hypotheses in the context of Senegalese agricultural cooperatives which seek, but mostly fail, to jointly sell their outputs in order to secure higher unit prices. We show that revealing farmers’ intended sales yielded enhanced coordination in larger groups where coordination is initially more difficult, and to higher income for small-scale farmers. We also show that participation in the LFE affected future behavior in the RCT.Item STOCHASTIC MODELS FOR AIRPORT FACILITY DEVELOPMENT(2016) Sun, Yanshuo; Schonfeld, Paul M.; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)An essential task of airport authorities is to plan airport facilities that meet future traffic needs in a dynamic and uncertain environment. Major technical difficulties in airport facility development stem from: (1) distinct construction and operating characteristics of different airport components; (2) nonlinear congestion effects affecting most airport facilities; and (3) complex interactions between airport user flows and facilities, which means that decisions regarding various facilities are interrelated. Potential demand fluctuations in a deregulated aviation market, combined with various other uncertainties, add further dimensions to the airport capacity planning problem. The core of airport facility development is to determine the timing and sizing of facility expansion projects. The traditional airport master planning has been criticized for its limited ability to cope with future uncertainties. Although there are several general procedures and frameworks for improving the planning flexibility or adaptability in uncertain environments, these macro analyses are considered only conceptually useful and cannot generate detailed plans for implementation. Very few relevant studies are found and all of them focus on a single component (e.g., passenger terminal) or specific facility. However, an airport is a system of many components, which can operate in parallel or in series. In airport development, it is desirable to roughly equalize the capacities of facilities operating in-series. Therefore, the present work is distinguished by the design of global planning models which can coordinate the development of various components under several sources of uncertainties. Due to the intricacy of the airport facility development problem, this dissertation presents a series of applied decision tools sequentially. Practical considerations, such as economies of scale, future cost discounting, nonlinear congestion, and project implementation time requirement, are captured in proposed optimization models which combine the difficulty of optimizing over binary variables and handling nonlinear relations. After examining the structural properties of optimization models, some simplification techniques are proposed, such as the out-approximation and discrete-approximation linearization methods, for enhancing solution efficiency and quality. Computational experiments demonstrate the benefits of such models. For instance, the total cost could be reduced significantly (e.g., by 18.8% in one test) with the proposed stochastic model, compared with decisions based on the average conditions. The decision tools developed can augment the airport master planning process in its ability to address future uncertainties. This work also offers methodological contributions in the field of infrastructure development, such as modeling of complex facility performances and a method for coordinating the development of various types of facilities.Item INTEGRATION OF INTRA-AUDITORY MODALITIES FOR THE ENHANCEMENT OF MOTOR PERFORMANCE AND COORDINATION IN A CONSTANT FORCE PRODUCTION TASK(2015) Koh, Kyung; Shim, Jae Kun; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)One of most fundamental problems in the field of neuromechanics is to understand how the central nervous system (CNS) integrates multiple sources of sensory information and coordinates multiple effectors in human movement. Much attention has been directed to the integration of multiple modalities between sensory organs (e.g., visual and auditory, visual and tactile, or visual and proprioceptor), while little is known about the integration of multiple modalities within one sensory (i.e., intra-sensory integration), especially regarding the auditory sensory. This dissertation investigated the mechanisms of intra-auditory integration for the control of multiple fingers during constant force production tasks, specifically regarding how the CNS utilizes multiple sources in auditory feedback, how the CNS deals with uncertainty in auditory feedback, and how the CNS adapts or learns a motor task using auditory feedback. The specific aims of this dissertation included: 1) development of analytical tools for the quantification of motor performance and coordination in a hierarchical structure of motor variability; 2) investigation into the effect of intra-auditory integration on motor performance and coordination (Experiment I); 3) investigation of the role of uncertainty in auditory information on the effectiveness of intra-auditory integration in motor performance and coordination (Experiment II); and 4) investigation of the auditory-motor learning in the context of motor performance and coordination (Experiment III). Results from Experiments I & II have indicated that the CNS can integrate frequency and intensity of auditory information to enhance motor performance and coordination among fingers. Intra-auditory integration was found to be most effective when uncertainty in auditory feedback was moderate between two extreme levels of uncertainty (low and high uncertainty). Results from Experiment III indicate that practice leads to the enhancement of performance by reducing individual finger variability without changes in inter-finger coordination. Further, the enhancement of performance and coordination after practice was specific to the intra-auditory modality that was available during practice. This dissertation discusses the mechanisms responsible for the changes in motor performance and coordination with auditory feedback and directions for future research are suggested.Item Effect of Transaction Cost and Coordination Mechanisms on the Length of the Supply Chain(2005-12-05) Iyengar, Deepak; Bailey, Joseph P.; Evers, Philip T.; Decision and Information Technologies; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)A drastic reduction in the cost of transmitting information has tremendously increased the °ow and availability of information. Greater availability of information increases the ¯rm's ability to manage its supply chain and, therefore, increases its operational performance. However, current literature is ambiguous about whether increased information °ows leads to either a reduction or increase in transaction cost, which enable supply chains to migrate towards more market-based transactions or hierarchal-based transactions. This research empirically demonstrates that the governance structure of the supply chains changes towards market-based transactions due to a lowering of transaction costs after 1987. Much of the results is based on the theory of Transaction Cost Economics (TCE) and the role of asset speci¯city, uncertainty, and frequency in determin- ing whether or not industries are moving towards markets or hierarchies. Unlike previous supply chain management literature that focuses on relatively short supply chains consisting of two or three supply chain members, Input-Output tables allow for analysis of supply chains with many more members. This paper uses the 1982, 1987, 1992, and 1997 U.S. Benchmark Input-Output tables published by the Bureau of Economic Analysis to analyze supply chains. In so doing, this dissertation not only provides insight into how supply chain structures are changing but also o®ers a sample methodology for other researchers interested in using Input-Output analysis for further supply chain management research. The second part of the dissertation focuses on looking at the e®ect of di®erent coordination mechanisms on supply chain length and supply chain performance using simulation. Three di®erent heuristics that model ordering policies are used to simulate coordination mechanisms. E±ciency is measured on the basis of minimized total net stock for each heuristic used. The results are checked for robustness by using four di®erent demand distributions. The results indicate that if a supply chain has minimized its net stock, then the heuristic used by various echelons in the supply chain need not be harmonized. Also, disintermediation helps in improving the performance of the supply chain.