Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 69). / For fresh produce, the product freshness is a key value to end consumers. Retailers try to maximize product freshness at retail stores while maintaining high product availability. Fresh produce that is close to the end of its life cycle will either be scrapped or be sold at a much lower price. With an increasing demand volatility and complication of supply chain network, obsolescence cost from these spoilages has been increasing recently. Our research focuses on the study of multi-echelon inventory optimization for fresh produce. We investigated the impacts of an additional fulfillment center in a supply chain to justify an improvement in product freshness. We analyzed three relevant factors: transit time, inventory dwell time and safety time, which affect the time products spend in a supply chain from the suppliers to the retail stores. Our objective was to create a predictive model that could determine whether product freshness could be improved when those products are shipped through a supply chain network with an additional fulfillment center. While a fulfillment center increases the total transit time by adding more "touches" of the inventory, it can provide benefits by reducing demand variability through the risk pooling effect. When an fulfillment center aggregates demand from several grocery distribution centers, it pools the demand volatility across various locations, thus reducing the demand volatility and the safety stock. Our model demonstrated that, with a fulfillment center, six product categories (Berries, Watermelons, Cherries, Mixed melons, Stone fruit, and Strawberries) had a decrease in the safety time that is more than the increase in total transit time, resulting in the improved product freshness at retail stores. Further, we defined a term "Enhance Coefficient of Variation (ECV)" to quantify the demand volatility. Finally, we determined a set of minimum ECV ratios in order to make an fulfillment center benefits the product freshness under different replenishment frequencies. Retailers can use this ECV ratio as an indicator to make channeling decisions. / by Saran Limvorasak and Zhiheng Xu. / M.Eng.in Logistics

Thesis: M. Eng. in Logistics, Massachusetts Institute of Technology, Engineering Systems Division, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 78-79). / Non-asset backed third-party logistics companies provide shippers access to a flexible source of capacity through transportation carrier spot market. The increased volatility in the trucking spot market rates is turning the 3PL businesses more risky and complex. To maximize profitability, a better understanding of the risk and the volatility patterns across the different geographies, time periods and other factors are investigated based on three years of real spot market data from a major 3PL company in US. Throughout this research we investigate the nature of trucking spot market volatility to allow truckload service providers to reduce their risk when setting long-term contracts. Using three different measures of volatility we are able to assess the company's risk profile and arise with insights to improve truckload service providers' business. / by Sriram Kishore Chittella and Marcos Machado Teixeira. / M. Eng. in Logistics

Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, 2008. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Includes bibliographical references (p. 101-105). / With advanced autonomy, Unmanned Aerial Vehicle (UAV) operations will likely be conducted by single operators controlling multiple UAVs. As operator attention is divided across multiple supervisory tasks, there is a need to support the operator's awareness of the state of the tasks for safe and effective task management. This research explores enhancing audio cues of UAV interfaces for this futuristic control of multiple UAVs by a single operator. This thesis specifically assesses the value of continuous and discrete audio cues as indicators of course-deviations or late-arrivals to targets for UAV missions with single and multiple UAVs. In particular, this thesis addresses two questions: (1) when compared with discrete audio, does continuous audio better aid human supervision of UAV operations, and (2) is the effectiveness of the discrete or continuous audio support dependent on operator workload? An experiment was carried out on the Multiple Autonomous Unmanned Vehicle Experiment (MAUVE) test bed with 44 military participants. Specifically, two continuous audio alerts were mapped to two human supervisory tasks within MAUVE. These continuous alerts were tested against single beep discrete alerts. The results show that the use of the continuous audio alerts enhances a single operator's performance in monitoring single and multiple, semi-autonomous vehicles. The results also emphasize the necessity to properly integrate the continuous audio with other auditory alarms and visual representations in a display, as it is possible for discrete audio alerts to be masked by continuous audio, leaving operators reliant on the visual aspects of the display. / by Hudson D. Graham. / S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, 2012. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 173-179). / When making technology choice decisions, firms must consider technology costs over time. In many industries, technology costs have been shown to decrease over time due to (a) improvements in production efficiency and the accumulation of worker experience accompanying production, known as "learning-by-doing," and (b) firm investments in research and development, worker training and other process improvement activities, known as "learning-by-investing." Rapid technological progress may mean that new technologies become available while existing technologies still exhibit learning-related cost reductions. In these cases, switching to a new technology means giving up these ongoing benefits while also incurring new technology introduction costs. Additionally, In some industries, high switching costs, regulatory compliance and/or the risks associated with new technologies may require firms to continue allocating production volume and investments to an existing technology whether or not a new technology is introduced. In these cases, firms must decide how to allocate finite production volume and investment resources between technologies. Learning is driven by resource allocation. Therefore, sharing finite resources among multiple learning technologies may reduce the learning-related benefits associated with each. This may lead firms to underestimate technology costs, leading to sub-optimal technology choice and resource allocation decisions. A methodology is presented which couples technology costs over time via capacity and investment resource allocation to characterize the impacts of (1) learning in an incumbent technology, and (2) resource allocation constraints, on technology choice and resource allocation decisions. Case studies in the semiconductor and automotive industries are examined using this method in combination with process based cost modeling. We find that (1) when the existing technology is still learning, diverting resources to a new technology results in an opportunity cost in both technologies which diminishes the benefits of switching technologies; (2) this effect can persist over a wide range of learning rates and technology costs; (3) capacity allocation constraints can significantly change the conditions under which the firm should choose a new technology, and (4) cumulative production volume and investment based learning differentially impact technology costs, leading to different cost-minimizing resource allocation decisions. / by Thomas Rand-Nash. / Ph.D.

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2004. / Includes bibliographical references. / Various retailers like Wal-Mart, Target, and Albertsons have announced their mandates asking their top suppliers to become RFID enabled beginning 2005. Meeting the mandate has become a sort of cost of doing business with Wal-Mart for suppliers. The objective of this thesis is to look for ways of meeting the mandate and preventing it from just becoming a cost of doing business with Wal-Mart. The thesis explores the various options available to suppliers and identifies the cost and benefit associated with each option and develops an evaluation methodology for the various options. / by Kapil Dev Singh. / M.Eng.in Logistics

Thesis (Ph. D.)--Massachusetts Institute of Technology, Biological Engineering Division, 2005. / Vita. / Includes bibliographical references (p. 108-111). / The objective of this work is to functionalize an existing polymer such that it better mimics natural tissue for tissue growth and regeneration. Numerous other processes have tried and accomplished this by non-specific protein adsorption, covalent attachment, biomolecule entanglement, and synthesis of new polymers with the desired functionality. The focus of this work is to modify the polymer's binding capability to cells while not altering the bulk properties. Through the use of both phage display of peptide libraries and yeast surface display of scFv libraries the surface of chlorine-doped polypyrrole (PPyCl) has been modified to facilitate binding of neuronal phenotype cells. The selection of peptides using phage display found a surface specific recognition peptide (T59) that was made bivalent by altering the C-terminus with an integrin binding epitope. The bivalency of the modified T59 peptide was exploited to tether phenochromocytoma (PC12) cells to the surface of PPyCl. Furthermore the tethering of the cells to PPyCl through the peptide does not decrease the cells neuronal function and maintains the bulk conductive polymers characteristics. Using the peptide as a bivalent linker, the addition of other types of cells, drugs, growth factors, and enzymes could be incorporated for various biomedical applications. / (cont.) An antibody (Y2) specific to PPyC1 was found using yeast surface display. This antibody was utilized to mediate cellular binding to PPyCl by expression of the antibody on the surface of PC12 cells. Complimenting the peptide studies of having an exterior bivalent linker the antibody recognition provides the means for any cell type to adhere to PPyCl, through expression of the antibody on the surface of the cell. This type of system could be used for various types of tissue growth supports. / by Kiley Preston-Halfmann Miller. / Ph.D.

Thesis (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 191-198). / This thesis considers ways in which humanitarian organizations can evaluate their performance internally, signal their performance to others, and what this might mean for the humanitarian relief community as a whole. Part I demonstrates an approach by which humanitarian organizations can develop key performance indicators (KPIs) to measure the performance of their logistics and supply chain activities, using a nonprofit specializing in the provision of medical relief as a case study. This thesis argues that a system of KPIs developed and analyzed by the organization can help improve operational performance, establish goals, and guide strategy. Part II then examines high-level organizational trends in the United States international relief sector, and questions whether contemporary literature on such trends find support in data from the Internal Revenue Service (IRS). This thesis argues that the humanitarian "market" today exists in a newly competitive state defined by this paper as "response-leadership." The humanitarian sector thus mirrors concentrated for-profit markets that embody the price-leadership model. This thesis finally suggests governmental and institutional policies concerning performance measurement that, given the competitive nature of the humanitarian marketplace defined in Part II, may improve market mechanisms in this sector. / by Thomas Henry Marcil. / S.M.in Technology and Policy

Thesis (Ph. D.)--Massachusetts Institute of Technology, Biological Engineering Division, 2008. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Includes bibliographical references (p. 163-168). / Biological engineers have constructed a number of multi-part synthetic biological systems that conduct logical operations on input signals, produce oscillatory output signals, store memory, or produce desired products. However, very few of these genetically-encoded systems worked as originally designed. The typical process of constructing a functional system involves a period of tuning the system properties to find a functional variant. This tuning process has been optimized and applied with great success to the engineering of individual biological parts by directed evolution. For instance, researchers developing improved enzymes, transcriptional promoters, and fluorescent proteins have generated large libraries of variants and screened these libraries to find individual mutants that met desired performance specifications. In this thesis, I address some of the bottlenecks preventing the application of directed evolution to more complex devices and systems. First, I describe an input / output screening plasmid that was designed to enable screening of higher-order genetic devices based on the equilibrium response of the device. This plasmid includes two fluorescent reporters and an inducible promoter to enable screening of device libraries across a range of inputs. Second, I describe measurement kits and reference standards designed to improve the characterization of promoter and RBS parts that are used as input substrates for device evolution. By using the kits, researchers are able to report promoter and RBS activities in standard units (Standard Promoter Units, SPUs, and Standard RBS Units, SRUs) enabling the growth of a collection of well-characterized parts to draw on for assembling device variants. Finally, I describe a new microfluidic device, the Sortostat, that integrates a cell sorting chamber with a previously published microscope-mounted microfluidic chemostat. / (cont.) Researchers can use the Sortostat to apply morphological, time-varying, or other complex selective pressures to cells in continuous culture. / by Jason R. Kelly. / Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, 2012. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 273-293). / In the near term, efficiency improvements represent a key option for reducing the impacts of climate change. The growing awareness of climate change has increased the attention regarding the carbon emissions "embedded" in the products we consume. This increased attention creates a need to measure and improve the carbon efficiency of the supply chains that produce those goods. In this thesis we present a method for measuring the carbon efficiency of a supply chain that recognizes the decentralized nature of supply chains. First, drawing from concepts in supply chain performance measurement and eco-efficiency we propose a definition of supply chain carbon efficiency that is consistent with the idea of a product's carbon footprint. We present Life Cycle Assessment (LCA), a method for quantifying the environmental impact of a product or service, as the appropriate method of measuring a product's carbon footprint and demonstrate the use of LCA through a case study involving the supply chain of bananas. Next, we characterize the difficulty and uncertainty in performing an LCA of a supply chain through an analysis of our case study of bananas. We present a framework to reduce the uncertainty though the concept of a carbon label. The carbon label provides a system where firms can measure the carbon footprint of their activities and share this information with their supply chain partners. We identify the role of third parties in facilitating information sharing and define the characteristics that describe the carbon label. Finally, we demonstrate how the carbon label works in the context of the supply chain. Through an analysis of the mode and carrier assignment steps in an integrated supply chain we develop new metrics that show how sharing information can increase the accuracy of the measured carbon footprint and improve decision-making. We provide incentive for firms to share information through the development of a vertical differentiation model of product carbon labels. Our model shows how consumer demand for lower carbon products drives reductions in the carbon footprint throughout the supply chain and induces firms to voluntarily disclose their carbon footprint. / by Anthony J. Craig. / Ph.D.

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2004. / "June 2004." / Includes bibliographical references (leaves 87-88). / While companies are looking for a single solution or a set of metrics that they can apply to measure their supply chain performance, it is clear that such a single solution does not exist. An effective supply chain performance measurement system has to align with a company's own supply chain processes. This thesis, based on the research of several established performance measurement models including the Balanced Scorecard and the SCOR Model, provides a framework for companies to build their supply chain performance measurement systems in-house. This thesis recommends a roadmap consisting of eight steps for companies to follow in the design and implementation phases of establishing a supply chain measurement system. The result is a set of 21 performance metrics is proposed that can be used by a company in the grocery retail industry to measure the efficiency of its supply chain. This metric set is well balanced because it encompasses six different criteria: comprehensive, causally oriented, vertically integrated, horizontally integrated, internally comparable, and useful. In conclusion, it is critical for companies from different industries to custom-tailor their own set of performance metrics, based on a careful evaluation of their individual business processes and supply chain performance objectives, that will allow management to do a better job utilizing existing capital resources and planning for strategic change and business development. / by Chih-Fen (Amy) Chou. / M.Eng.in Logistics