Source: Dissertation Abstracts International, Volume: 39-03, Section: B, page: 1527. / Thesis (Ph.D.)--The Florida State University, 1978.

Thesis advisor: Julie Mortimer / This dissertation estimates the impacts of a mandatory disclosure policy (the New York City grade law) on hygiene quality choices, prices, and competition.In the first and third chapters of my dissertation, I estimate a dynamic structural model to recover the implied costs underlying quality choice decisions. Though the researcher may not observe these costs in the data, they can be recovered empirically by considering how firm decision making changes depending on the conditions in play at the firm and in the market over time. Having a structural model also enables me to conduct counterfactual experiments, which show that several key parameters, such as sunk entry costs, or the value from competing in certain types of markets, can have a meaningful impact on the policy outcomes. My first chapter examines whether the grade law leads to increased product quality provision by firms selling differentiated products. I focus on Zagat rated restaurants, which prior to the grade law have many pre-existing quality characteristics valued by consumers that can differentiate them from other firms. I estimate a dynamic model of entry, exit and investment in hygiene quality, incorporating permanent firm-level unobserved heterogeneity, and find that the grade law increased payoffs from entering with, operating with, and investing in higher quality. However, I also show that underlying costs of providing quality affect firm decision making in the absence of mandatory disclosure, and that altering these costs can shift the distribution of quality types towards higher quality. I derive a counterfactual tax policy that directly targets these costs and leads to higher percentages of high quality firms across markets than the mandatory disclosure policy. My second chapter uses the same panel of Zagat restaurants as in Chapter 1, and estimates how the grade law affects the pricing decisions of restaurants with different hygiene qualities. Since the grade law introduces a new dimension of product quality, firms may be able to charge higher prices for access to high quality. However, because firms in this setting are already selling differentiated products, it is possible that prices do not change. Furthermore, prices charged by lower quality firms may fall, because consumers would not consume at a low quality firms without being compensated with a lower price, or the prices may not change or even rise, partially because consumers are still willing to pay for the firm's other quality characteristics. Controlling for firm characteristics and market conditions, I find that the introduction of the law led to a decrease in prices charged by lower quality firms relative to those charged by high quality firms. The results suggest that as quality levels increase in the market, consumers may benefit due to the decreased ability of firms to price discriminate as they would if there were asymmetric information on quality. However, I also find evidence that, as a result of the grade law, firms pass-through some of the costs of improving quality to consumers in the form of higher prices. My third chapter presents preliminary findings suggesting how the grade law impacts the hygiene quality choices of firms with few observable quality characteristics prior to mandatory disclosure. Using the same dynamic model framework as in Chapter 1, I estimate the effects of the grade law on the hygiene quality choices of bagel shops, and show how these choices relate to market competition. While most of the model results and predictions from this chapter are sensitive and should be interpreted with caution as they likely do not fully identify the parameters of interest, I do estimate a positive relationship between competition with high quality firms and choice of high quality after the grade law; however, I also find evidence that entry costs are increasing in quality. Counterfactuals show that lowering the costs of entry with high quality both before and after the grade law could increase the proportion of firms choosing high quality. Additionally, I find that the competitive interaction between firms provides an important incentive to investing in higher quality under mandatory disclosure. I interpret this finding as evidence that the effects of mandatory disclosure are primarily transmitted through competition, and that removing these effects of competition would significantly reduce the gains from mandatory disclosure. This research contributes to a growing literature on the efficacy and importance of mandatory disclosure policies. Mandatory disclosure can be a valuable policy tool used to target an inefficiency or social harm such as a high incidence of food poisoning at restaurants. However, the effect of these policies on the choices made by firms should also be considered. Firm quality choices after mandatory disclosure will be determined by consumer demand for the new dimension of product quality, competition with market rivals, and costs. Consumer demand for hygiene quality may depend on factors such as how much they pay for a meal, meaning that demand for hygiene quality may be different for limited-service restaurants than for full-service restaurants. However, allowing consumers, who may consider multiple characteristics of quality, not just hygiene, to provide the sole incentives for firms to improve their quality, may under-incentivize quality improvement of some firms. Furthermore, market conditions such as competition can be important, and may not be addressed at all by the consumer response. Policies that use cost-based incentives to firms, or target firms operating under certain market conditions, could be used as a replacement or supplement to the workings on the demand-side. My results suggest that such alternative policies which, rather than asking consumers to enforce product quality improvement via their consumption decisions, directly target the incentives faced by firms when making product quality choices, merit consideration. / Thesis (PhD) — Boston College, 2016. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.

Thesis (M.B.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-01

This thesis studies methods for tightening relaxations of optimization problems with convex objective values over a nonconvex domain. A class of linear inequalities obtained by lifting easily obtained valid inequalities is introduced, and it is shown that this class of inequalities is sufficient to describe the epigraph of a convex and differentiable function over a general domain. In the special case where the objective is a positive definite quadratic function, polynomial time separation procedures using the new class of lifted inequalities are developed for the cases when the domain is the complement of the interior of a polyhedron, a union of polyhedra, or the complement of the interior of an ellipsoid. Extensions for positive semidefinite and indefinite quadratic objectives are also studied. Applications and computational considerations are discussed, and the results from a series of numerical experiments are presented.

O óxido de etileno é um agente esterilizante dos mais importantes para materiais termo-sensíveis, dentre eles os artigos médico-hospitalares. Fios para sutura cirúrgica foram submetidos à exposição, em autoclave, a misturas gasosas com capacidade anti-microbiana, monitorando-se o processo através de Bacillus subtilis como indicador biológico. O objetivo deste estudo foi determinar a relação da letalidade do ciclo em função dos parâmetros de processo temperatura, tempo e pressão, expressando-a através de equações polinomiais decorrentes de modelo de ajuste pelo método da regressão linear múltipla. Os resultados analíticos e suas representações gráficas permitiram delimitar a região de letalidade, com simultânea confirmação da manutenção das características físicas farmacopeicas dos fios para sutura cirúrgica. Concluiu-se que o método estatístico empregado é adequado para a obtenção de equações de previsibilidade da atividade anti-microbiana em função dos parâmetros de processo. Além disto, a integridade física dos artigos médico-hospitalares foi preservada, assegurando-se sua utilização eficaz e segura. / Ethylene oxide is one of the most important sterilizing agents for thermo-sensitive materials, including the medical-hospital products. Strings for surgical sutures were exposed by autoclave to gaseous mixtures with anti-microbial properties, being the process monitored by Bacillus subtilis as a biological indicator. The purpose of this study was to determine the relation of cycle lethality in terms of process parameters (temperature, time and pressure) expressing them through polynomial equations decurrent of an adjustment model, by the multiple linear regression method. The analytical results and its graphic representations enabled us to delimit the lethal region having simultaneously the confirmation that the physical pharmacopeia requirements of the strings for surgical suture are maintained. It was concluded that the statistical method used is adequate to obtain equations of foreseeable anti-microbial activity in terms of process parameters. Besides, the physical integrity of the medical/hospital articles was preserved, so asserting its safe and effective use.

O óxido de etileno é um agente esterilizante dos mais importantes para materiais termo-sensíveis, dentre eles os artigos médico-hospitalares. Fios para sutura cirúrgica foram submetidos à exposição, em autoclave, a misturas gasosas com capacidade anti-microbiana, monitorando-se o processo através de Bacillus subtilis como indicador biológico. O objetivo deste estudo foi determinar a relação da letalidade do ciclo em função dos parâmetros de processo temperatura, tempo e pressão, expressando-a através de equações polinomiais decorrentes de modelo de ajuste pelo método da regressão linear múltipla. Os resultados analíticos e suas representações gráficas permitiram delimitar a região de letalidade, com simultânea confirmação da manutenção das características físicas farmacopeicas dos fios para sutura cirúrgica. Concluiu-se que o método estatístico empregado é adequado para a obtenção de equações de previsibilidade da atividade anti-microbiana em função dos parâmetros de processo. Além disto, a integridade física dos artigos médico-hospitalares foi preservada, assegurando-se sua utilização eficaz e segura. / Ethylene oxide is one of the most important sterilizing agents for thermo-sensitive materials, including the medical-hospital products. Strings for surgical sutures were exposed by autoclave to gaseous mixtures with anti-microbial properties, being the process monitored by Bacillus subtilis as a biological indicator. The purpose of this study was to determine the relation of cycle lethality in terms of process parameters (temperature, time and pressure) expressing them through polynomial equations decurrent of an adjustment model, by the multiple linear regression method. The analytical results and its graphic representations enabled us to delimit the lethal region having simultaneously the confirmation that the physical pharmacopeia requirements of the strings for surgical suture are maintained. It was concluded that the statistical method used is adequate to obtain equations of foreseeable anti-microbial activity in terms of process parameters. Besides, the physical integrity of the medical/hospital articles was preserved, so asserting its safe and effective use.

abstract: With the development of computer and sensing technology, rich datasets have become available in many fields such as health care, manufacturing, transportation, just to name a few. Also, data come from multiple heterogeneous sources or modalities. This is a common phenomenon in health care systems. While multi-modality data fusion is a promising research area, there are several special challenges in health care applications. (1) The integration of biological and statistical model is a big challenge; (2) It is commonplace that data from various modalities is not available for every patient due to cost, accessibility, and other reasons. This results in a special missing data structure in which different modalities may be missed in “blocks”. Therefore, how to train a predictive model using such a dataset poses a significant challenge to statistical learning. (3) It is well known that different modality data may contain different aspects of information about the response. The current studies cannot afford to solve this problem. My dissertation includes new statistical learning model development to address each of the aforementioned challenges as well as application case studies using real health care datasets, included in three chapters (Chapter 2, 3, and 4), respectively. Collectively, it is expected that my dissertation could provide a new sets of statistical learning models, algorithms, and theory contributed to multi-modality heterogeneous data fusion driven by the unique challenges in this area. Also, application of these new methods to important medical problems using real-world datasets is expected to provide solutions to these problems, and therefore contributing to the application domains. / Dissertation/Thesis / Doctoral Dissertation Industrial Engineering 2019

abstract: The shift in focus of manufacturing systems to high-mix and low-volume production poses a challenge to both efficient scheduling of manufacturing operations and effective assessment of production capacity. This thesis considers the problem of scheduling a set of jobs that require machine and worker resources to complete their manufacturing operations. Although planners in manufacturing contexts typically focus solely on machines, schedules that only consider machining requirements may be problematic during implementation because machines need skilled workers and cannot run unsupervised. The model used in this research will be beneficial to these environments as planners would be able to determine more realistic assignments and operation sequences to minimize the total time required to complete all jobs. This thesis presents a mathematical formulation for concurrent scheduling of machines and workers that can optimally schedule a set of jobs while accounting for changeover times between operations. The mathematical formulation is based on disjunctive constraints that capture the conflict between operations when trying to schedule them to be performed by the same machine or worker. An additional formulation extends the previous one to consider how cross-training may impact the production capacity and, for a given budget, provide training recommendations for specific workers and operations to reduce the makespan. If training a worker is advantageous to increase production capacity, the model recommends the best time window to complete it such that overlaps with work assignments are avoided. It is assumed that workers can perform tasks involving the recently acquired skills as soon as training is complete. As an alternative to the mixed-integer programming formulations, this thesis provides a math-heuristic approach that fixes the order of some operations based on Largest Processing Time (LPT) and Shortest Processing Time (SPT) procedures, while allowing the exact formulation to find the optimal schedule for the remaining operations. Computational experiments include the use of the solution for the no-training problem as a starting feasible solution to the training problem. Although the models provided are general, the manufacturing of Printed Circuit Boards are used as a case study. / Dissertation/Thesis / Masters Thesis Industrial Engineering 2019

Tese de mestrado. Design Industrial. Faculdade de Engenharia. Universidade do Porto. 2005

Dissertação apresentada para obtenção do grau de Mestre em Engenharia Electrotécnica e de Computadores, na Faculdade de Engenharia da Universidade do Porto, sob a orientação da Prof. Doutora Zita Maria Almeida do Vale