Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2005. / Includes bibliographical references (leaves 79-80). / This thesis examines the supply chain management practices of the Boeing Commercial Airplane Company within the context of the global aerospace industry. The methodology used for this study includes a study of emerging supply chain management concepts and practices in the aerospace industry based on a review of the open literature, research performed on aerospace supply chain management issues by MIT's Lean Aerospace Initiative, and selected interviews with aerospace industry experts. The results show that there are significant changes in supply chain management practices in the aerospace industry. These changes include restructuring and closer integration of supplier networks to achieve efficiency gains, delegating greater design and production responsibility to major suppliers through strategic supplier partnerships along with having key suppliers evolve greater system and subsystem integration capabilities, emphasizing a lifecycle view supply chain design and management to reduce lifecycle cost of products and systems, and building supply chain capabilities supporting maintenance and aftermarket logistics services as a major new strategic thrust to provide improved customer satisfaction and retain long-term customer loyalty. The thesis focuses on Boeing's supply chain management practices through a case study to explore these developments in a more concrete enterprise context. / by Daglar Cizmeci. / M.Eng.in Logistics

Thesis (Ph. D.)--Massachusetts Institute of Technology, Biological Engineering Division, 2005. / Includes bibliographical references (p. 252-285). / Glycosaminoglycans (GAGs) are complex polysaccharides that exist both on the cell surface and free within the extracellular matrix. The intrinsic sequence variety stemming from the large number of building blocks that compose this biopolymer leads to substantial information density as well as to the ability to regulate a wide variety of important biological processes. With the recent and progressive emergence of biochemical and analytical tools to probe GAG structure and function, efforts can be taken to understand the role of GAGs in cell biology and in disease in the various physiological locations where GAGs can exist. As a first step to probe the functions of GAGs, the heparin/heparan sulfate-GAG (HSGAG)-fibroblast growth factor (FGF) system was examined. Understanding the role of HSGAGs in inducing FGF2 dimerization led to the development of a novel engineered protein that was found to be effective at promoting functional recovery in stroke. Subsequently, methods to isolate HSGAGs from the cell surface were optimized and the ability of HSGAGs to support FGF signaling was investigated. Cell surface HSGAGs can define the responsiveness of a given cell to FGF1 and FGF2 through multiple receptor isoforms. Stromal cell derived HSGAGs were also identified as critical regulators of tumor cell growth and metastasis, effecting not only FGF2., but also 1-integrin signaling. / (cont.) Other GAGs, including dermatan sulfates, were characterized as modulators of FGFs and vascular endothelial growth factors. Finally, FGFs and HSGAGs were found to have important roles in maintaining epithelial monolayer integrity, with syndecan-l serving as a critical factor in inflammatory bowel disease. In addition to understanding HSGAGs in their normal physiological settings, techniques to internalize them were developed. Poly(3-amino ester)s were found to condense heparin and enable its endocytosis into cells. Internalized heparin is preferentially taken up by cancer cells, which often have a faster endocytic rate than non-transformed cells, and promotes apoptotic cell death. Internalized heparin can also be used as a tool to probe cell function. In Burkitt's lymphoma, poly(3-amino ester)-heparin conjugates served to identify cell surface HSGAGs as an important modulator of cell growth that can be harnessed to inhibit growth. Finally, studies that sought to broaden the scope of GAG biology were undertaken. Cell surface HSGA(:is were identified as mediators of vascular permeability. Furthermore a novel technique to immobilize GAGs was employed. The interactions between GAG and substrate were via hydrogen bonding. Immobilization of GAGs alters their properties, such that they can affect cells in ways distinct from GAGs free in the ECM. / (cont.) Furthermore, immobilized GAGs can regulate cancer cell adhesion, growth and progression, and may offer a new way to regulate the activity of cancer cells. In addition to directly providing new potential therapeutics and drug targets, these studies represent a foundation to enable additional studies of GAG function. Future work harnessing the techniques presented may open new avenues of research and facilitate the development of novel GAG-based therapeutics. / by David Berry. / Ph.D.

Thesis: Ph. D., Massachusetts Institute of Technology, Engineering Systems Division, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 219-227). / The combination of air traffic growth and airport capacity limitations has resulted in significant congestion throughout the US National Airspace System, which imposes large costs on the airlines, passengers and society. Absent opportunities for capacity expansion, the mitigation of air traffic congestion requires improvements in (i) the utilization of airport capacity to enhance operating efficiency at the tactical level (i.e., over each day of operations), and/or (ii) the allocation of airport capacity to the airlines to limit over-capacity scheduling at the strategic level (i.e., months in advance of the day of operations). This thesis develops an integrated approach to airport congestion mitigation that jointly optimizes the utilization of airport capacity and the design of airport capacity allocation mechanisms. First, we focus on airport capacity utilization. We formulate an original Dynamic Programming model that optimizes, at the tactical level, the selection of runway configurations and the balancing of arrival and departure service rates to minimize congestion costs, for any given schedule of flights. The model integrates the stochasticity of airport operations into a dynamic decision-making framework. We implement exact and approximate Dynamic Programming algorithms that, in combination, enable the real-time implementation of the model. Results show that optimal policies are path-dependent, i.e., depend on prior decisions and on the stochastic evolution of the system, and that the model can reduce congestion costs, compared to advanced heuristics aimed to replicate typical decisions made in practice and to existing approaches based on deterministic queue dynamics. Second, we integrate the model of airport capacity utilization into a macroscopic queuing model of airport congestion. The resulting model quantifies the relationships between flight schedules, airport capacity and flight delays at the strategic level, while accounting for the way airport capacity utilization procedures can vary tactically to maximize operating efficiency. Results suggest that the model estimates the average departure queue lengths, the variability of departure queue lengths and the average arrival and departure delays at the three major airports in the New York Metroplex relatively well. The application of the model shows that the strong nonlinearities between flight schedules and flight delays observed in practice are captured by the model. Third, we develop an Integrated Capacity Utilization and Scheduling Model (ICUSM) that jointly optimizes scheduling interventions for airport capacity allocation at the strategic level and airport capacity utilization at the tactical level. Scheduling interventions start with a schedule of flights provided by the airlines, and reschedule a selected set of flights to reduce imbalances between demand and capacity, while minimizing interference with airline competitive scheduling. The ICUSM optimizes such interventions, while accounting for the impact of changes in flight schedules on airport operations. It relies on an original modeling architecture that integrates a Stochastic Queuing Model of airport congestion, our Dynamic Programming model of capacity utilization, and an Integer Programming model of scheduling interventions. We develop an iterative solution algorithm that converges in reasonable computational times. Results suggest that substantial delay reductions can be achieved at busy airports through limited changes in airline schedules. It is also shown that the proposed integrated approach to airport congestion mitigation performs significantly better than a typical sequential approach where scheduling and operating decisions are made separately. Last, we build upon the ICUSM to design, optimize and assess non-monetary mechanisms for scheduling interventions that ensure inter-airline equity and enable airline collaboration. Under the proposed mechanism, the airlines would provide their preferred schedules of flights, their network connections, and the relative scheduling flexibility of their flights to a central decision-maker, who may then consider scheduling adjustments to reduce anticipated delays. We develop a lexicographic architecture that optimizes such interventions based on efficiency (i.e., meeting airline scheduling preferences), equity (i.e., balancing scheduling adjustments fairly among the airlines), and on-time performance (i.e., mitigating airport congestion) objectives. Theoretical and computational results suggest that inter-airline equity can be achieved at no, or small, losses in efficiency, and that accounting for airline scheduling preferences can significantly improve the outcome of scheduling interventions. / by Alexandre Jacquillat. / Ph. D.

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 53-54). / Agriculture is an industry where historical and current data abound. This paper investigates the numerous data sources available in the agricultural field and analyzes them for usage in supply chain improvement. We identified certain applicable data and investigated methods of using this data to make better supply chain decisions within the agricultural chemical distribution chain. We identified a specific product, AgChem, for this study. AgChem, like many agricultural chemicals, is forecasted and produced months in advance of a very short sales window. With improved demand forecasting based on abundantly-available data, Dow AgroSciences, the manufacturer of AgChem, can make better production and distribution decisions. We analyzed various data to identify factors that influence AgChem sales. Many of these factors relate to corn production since AgChem is generally used with corn crops. Using regression models, we identified leading indicators that assist to forecast future demand of the product. We developed three regressions models to forecast demand on various horizons. The first model identified that the price of corn and price of fertilizer affect the annual, nation-wide demand for the product. The second model explains expected geographic distribution of this annual demand. It shows that the number of retailers in an area is correlated to the total annual demand in that area. The model also quantifies the relationship between the sales in the first few weeks of the season, and the total sales for the season. And the third model serves as a short-term, demand-sensing tool to predict the timing of the demand within certain geographies. We found that weather conditions and the timing of harvest affect when AgChem sales occur. With these models, Dow AgroSciences has a better understanding of how external factors influence the sale of AgChem. With this new understanding, they can make better decisions about the distribution of the product and position inventory in a timely manner at the source of demand. / by Derik Lafayette Smith and Satya Prakash Dhavala. / M.Eng.in Logistics

Thesis (S.M.)--Massachusetts Institute of Technology, Biological Engineering Division, 2006. / Includes bibliographical references (leaves 44-45). / There is a great need in the fields of biology, medicine, and pharmaceuticals to create high-throughput devices for the detection of specific cell states in a heterogeneous mixture of cells. The desire is to differentiate among diseased and healthy cells, cell age, and cell type with the minimum amount of sample pretreatment. This project addresses this need by developing microfluidic devices that exploit the adhesion differences between cell states and cell types to rapidly count cells of different types without the need for labels. There are two avenues in which to explore cell adhesion differences with these devices, the first is a net electrostatic change at the surface of the cell wall and the second is the presence of specific cell-membrane adhesion proteins. It is hypothesized that the forced interaction of the cell wall with the microfabricated microcapillary walls would result in a differential velocity based on cell type that could be detected simply using a microscope and video camera or an interferometer. The eventual integration of cell velocity detection would result in a portable all-inclusive lab-on-a-chip system that could be used in the field for detecting the presence of diseases, such as malaria and cancer as well as in a lab setting for drug discovery. / by Kristen M. Naegle. / S.M.

Thesis (Ph. D. in Molecular and Systems Bacterial Pathogenesis)--Massachusetts Institute of Technology, Biological Engineering Division, 2005. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Includes bibliographical references. / Helicobacter hepaticus infection of A/JCr mice is a model of liver cancer resulting from chronic active inflammation. We monitored hepatic global gene expression profiles and correlated them to histological liver lesions in H. hepaticus infected and control male A/JCr mice at 3 months, 6 months, and 1 year of age. We used an Affymetrix-based oligonucleotide microarray platform on the premise that a specific genetic expression signature at isolated time points would be indicative of disease status. Model based expression index comparisons generated by dChip yielded consistent profiles of differential gene expression for H. hepaticus infected male mice with progressive liver disease versus uninfected control mice within each age group. Linear discriminant analysis and principal component analysis allowed segregation of mice based on combined age and lesion status, or age alone. Up-regulated genes present throughout the 12 month study involved inflammation, tissue repair, and host immune function. Upregulation of putative tumor and proliferation markers correlated with advancing hepatocellular dysplasia. Transcriptionally down-regulated genes in mice with liver lesions included those related to peroxisome proliferator, cholesterol, and steroid metabolism pathways. Transcriptional profiling of hepatic genes documented gene expression signatures in the livers of H. hepaticus infected male A/JCr mice with chronic progressive hepatitis and preneoplastic liver lesions, complemented the histopathological diagnosis, and suggested molecular targets for the monitoring and intervention of disease progression prior to the onset of hepatocellular neoplasia. Our laboratory, in collaboration with Professors Suerbaum and Schauer, recently identified a / (cont.) 70kb genomic island in Helicobacter hepaticus strain ATCC 51488 as a putative pathogenicity island (HhPAI) (Suerbaum et al, PNAS, 2003). This region within H. hepaticus contains genes HH0233-HH0302, a differential GC content, several long tandem repeats but no flanking repeats, and three components of a type IV secretion system (T4SS). A/JCr mice were experimentally infected with three naturally occurring strains of H. hepaticus including the type strain H. hepaticus ATCC 51488 strain (Hh 3B1) isolated from A/JCr mice, MIT 96-1809 (Hh NET) isolated from mice shipped from the Netherlands, and MIT-96-284 (HhG) isolated from mice acquired from Germany.4 HhNET (missing most of the HhPAI) infected male A/JCR mice exhibited a significantly lower prevalence (p<.05) of hepatic lesions at 6 months post infection than Hh 3B1 with an intact HhPAI. Hh G also has a large segment of the genomic island deleted, but not as many genes are deleted as compared to Hh NET. Hh G also demonstrated a lower prevalence of hepatic lesions. This variable pathological effect was evident in male mice only. The severity of chronic active inflammation in the liver of the H. hepaticus infected A/JCr mice depended on H. hepaticus liver colonization levels. The in vivo results support the presence of the HhPAI as a legitimate virulence determinant and predictor of severity of liver lesions in H. hepaticus infected A/JCr male mice. To further determine the differences in virulence of the H. hepaticus strains Hh 3B1, Hh NET, Hh G and an isogenic mutant H. ... / by Samuel R. Boutin. / Ph.D.in Molecular and Systems Bacterial Pathogenesis

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2009. / Includes bibliographical references (leaf 52). / The focus of this research is creating a framework to accurately assess the benefits of hub capability in an international distribution network for fast moving consumer packaged goods. The traditional inventory centralization dilemma requires an evaluation of whether the reduction in holding costs outweighs the increases in transportation and handling costs. We developed a mixed integer programming model to determine the benefits of adding hub capability to Consumer Co.'s Northwest Latin American import supply chain. Consumer Co.'s NWLA division imports products from Argentina, Brazil and Mexico to eleven countries within Central and South America, each operating a distribution center. By adding hub capability in the Colon Free Trade Zone, our model determined that the lowest cost could be achieved using a "Hybrid" solution, where some channels flowed through the hub and others were shipped direct. This network design would result in a 4.4% reduction in annual relevant costs. A counter-intuitive revelation was the fact that transportation costs could actually decrease. Similar to airlines, carriers can sometimes offer lower rates for indirect shipments passing through a high volume transit point instead of shipping the product directly through a less traveled route. Hub capability in the Colon Free Trade Zone also provides Consumer Co. with the flexibility to tailor their supply chain to potential changes in the fluctuating Latin American environment. Increasing customer expectations can lead to scenarios with higher safety stocks, for which centralization can provide the highest benefits. / by Sebastian Ortiz Duran and Richard Hawks. / M.Eng.in Logistics

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2009. / Includes bibliographical references (leaf 60). / This thesis presents a framework for deciding which products to centralize in a regional distribution center and which products to store decentralized close to the customer sites, for each facility in a multi-echelon distribution network. Our research specifically focuses on developing an optimization model to determine the inventory positioning strategy that minimizes total costs. The model considers both inbound and outbound transportation costs along with inventory holding costs at all facilities in the network. The total cost and responsiveness of the optimal solution are compared with the baseline network, in which inventory is completely decentralized. Our analysis is performed using several products that have diverse characteristics, in terms of demand patterns, lead-times, product costs, service-level requirements, transportation modes, and supplier locations. A sensitivity analysis is performed to study how a variance in these parameters affects the optimal solution. The research suggests that for high volume commodity items the benefits of centralization are highly dependent upon the degree of lane consolidation. However, for low volume specialty items, centralization can provide immediate benefits with no change to the existing transportation network. / by Deepak Avari and Naman Dayal. / M.Eng.in Logistics

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2010. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 68-73). / Historically, the apparel industry has operated in an unsustainable way. Materials, energy, and other resources are used inefficiently throughout the apparel supply chain, leading to unsustainable levels of waste generation. Post-purchase use and disposal are rarely considered during the design and production of apparel products. Apparel companies are becoming more cognizant of their environmental impact and are implementing sustainability programs to counteract these issues. The field of sustainable supply chain management is a relatively new concept and companies face the challenges of choosing sustainability initiatives, measuring the success of those initiatives, and assessing their overall progress toward sustainability. This thesis addresses these three challenges. First, it compiles a comprehensive set of nearly 300 sustainability initiatives used by eight apparel companies. Second, it documents the initiatives' associated metrics, which were found to exist for only 30 percent of the initiatives. Third, it provides a system for measuring overall corporate sustainability through an initiative classification scheme. It was determined that three of the eight companies studied embody the highest level of corporate sustainability. The industry has made progress toward becoming more sustainable, but cannot be truly sustainable until systemic changes are made to the design, production, use, and disposal stages of the apparel product life cycle. / by Sophie Elise Agbonkhese. / M.Eng.in Logistics

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 172-177). / As economies develop and trade routes change, investment in port infrastructure is essential to maintain the necessary capacity for an efficiently functioning port system and to meet expected demand for all types of cargo. However, these largescale, expensive investments in long-term infrastructure assets must be made despite a variety of future uncertainties that may potentially influence a port's performance. By using a Southeast Asian multi-purpose port as a case study, this thesis paper enhances the investment decision-making process for port infrastructure through the successful application and modification of two existing methodologies and the development of both an investment tool and a framework for selecting an optimal investment strategy to address capacity constraints within a port system. Applied at the case study port, the research evaluates a modification of an existing methodology for the measurement of port capacity, developed by Lagoudis and Rice, to identify bottlenecks within the port system. The research then examines a modification of an existing methodology, developed by de Neufville and Scholtes, for the evaluation of potential investment strategies under uncertainty. A simulation screening model is developed to forecast expected profitability under uncertainty for potential investment strategies, including strategies with flexible options, and to determine the optimal strategy. The thesis concludes with the presentation of a decision-making process for port infrastructure investment and recommended refinements to the existing methodologies. / by Jason Bryan Salminen. / M.Eng.in Logistics