Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, 2007. / MIT Barker Engineering Library copy: printed in pages. / Also issued printed in pages. / Includes bibliographical references (leaves 141-146). / This thesis presents a new modeling framework and research methodology for the study of engineering systems. The thesis begins with a formal conceptualization of Engineering Systems based upon a synthesis of various literatures. Using this conceptualization, a new modeling framework is presented called the Engineering Systems Matrix (ESM). The ESM is an improvement to existing system-level modeling frameworks, such as the Design Structure Matrix (DSM), by providing a dynamic, end-to-end representation of an engineering system. In support of this contribution, a new research methodology is presented called Qualitative Knowledge Construction (QKC). QKC can be thought of as a Bayesian-type approach to grounded theory. The methodology integrates qualitative social science with quantitative methods by developing a procedure for translating textual reports of observations, interview transcripts, system documentation, and figures into coded data represented in the ESM. The thesis develops the ESM framework and the QKC methodology in the context of a real world engineering system, a US Air Force miniature uninhabited air vehicle (MAV) product development system. / by Jason E. Bartolomei. / Ph.D.

Thesis (S.M. in Technology & Policy)--Massachusetts Institute of Technology, Engineering Systems Division, 2013. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 103-112). / Greenhouse gases are being emitted at an increasing rate, which may cause irreversible damage to the earth's climate. Considering the magnitude of CO₂ emissions from industrial facilities and power plants, carbon capture and storage (CCS) is expected to play an important role in mitigating climate change. The estimated contribution of CCS to a given emissions reduction target depends on assumptions made about various factors such as the availability of the technology, the availability of substitutes such as nuclear technology, and the stringency of emissions reduction targets. Given that the global energy economy has largely been operating in "business as usual" mode, the effective implementation of a carbon policy is likely to be delayed. In addition, other trends in the energy sector such as the availability of inexpensive gas-based generation and the uncertainty related to nuclear capacity expansion may also have an impact on the role of CCS. Part A of this thesis analyzes the importance of CCS as a mitigation technology under different future policy responses and incorporating these current trends. Using the Emissions Prediction & Policy Analysis (EPPA) model developed by the Joint Program on the Science & Policy of Global Change at the Massachusetts Institute of Technology (MIT), the study finds that the more stringent the emission caps, the more important the role of CCS becomes. In addition, the role of natural gas based generation is found to be transitional in its contribution to emissions reduction. Consequently, the availability of inexpensive gas-based generation does not eliminate the need for CCS towards the end of the century. Furthermore, advanced nuclear technology and CCS are found to be close substitutes for technologies that serve the needs of a low-carbon economy in the latter half of the century. The role of one technology, therefore, is in part determined by how technological development and cost reduction occurs in the other. Part B of this thesis focuses on challenges experienced in the current demonstration phase of CCS technology development. Most demonstration projects are typically supported by a combination of policy incentives such as grants, investment tax credits, production tax credits, loan guarantees, or additional sources of revenue. Regardless, many of these demonstration projects have been cancelled in the recent past primarily due to poor project economics. A financial model was developed and used to analyze the impact of each of these policy incentives on project economics. In addition, case studies have been conducted on two major demonstration projects: ZeroGen (Australia) and the Kemper Country (USA). The study finds that even with the combined impact of all incentives, first-of-a-kind CCS plants are not economical when compared to supercritical pulverized coal plants. CCS and similar low carbon technologies are also facing increasing economic pressure from cheaper natural gas-based electricity. These factors, in addition to endogenous risks associated with first-of-a-kind plants, are likely to deter potential developers. Therefore, CCS demonstration plants may require other policy mechanisms such as a rate-based pay that allow costs to be passed on to consumers. Policymakers may need to consider the distributional impacts of such a mechanism because costs are borne by consumers within a particular jurisdiction whereas the benefits of commercializing CCS accrue to a larger group of consumers. Regardless, incurring costs in the short-term may be inevitable to ensure the availability of CCS as a competitive, longer-term low carbon technology option. / by Sadia P. Raveendran. / S.M.in Technology & Policy

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2004. / "June 2004." / Includes bibliographical references (leaf 52). / This thesis provides a method for hi-tech companies to evaluate reverse logistic software and services. To clarify what is reverse logistics, the definition and features of reverse logistics are first introduced. The reasons to improve reverse logistics management systems are explained. Information of reverse logistics software systems and service vendors is collected, compared and analyzed. Current reverse logistics market trends are analyzed and problems in evaluating reverse logistics systems are identified. An algorithm to evaluate the software and service is established and explained. Parameters are analyzed and determined. Various vendors are selected and interviewed. Their capabilities/strengths are rated. As an example, the evaluation points for several software systems are calculated in the case of a semi-conductor company. Research limits are also provided. Conclusions are presented at the end of the thesis. / by Jinfan Li. / 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. 60). / Improving forecast accuracy has positive effects on supply chain performance. Forecast accuracy can reduce inventory levels, increase customer service levels and responsiveness, or a combination of the two. However, the further upstream in the supply chain, the more difficult it becomes to forecast accurately. Demand for consumer products might be subject to factors that are hard to identify and quantify. One way to overcome this is to observe external factors or predictors that might help explain demand. The purpose of this thesis is to explore the factors that potentially influence the demand of a fast-moving consumer product (bottled water), and build a demand signal repository for these factors to help the manufacturer generate more accurate forecasts. We identified more than 30 such factors that might affect demand, using interviews and industry research. We tested more than 200 causal models of the relationship between observed demand and the predicting factors. The resulting model explained almost 60% of demand for two out of three customers using daily buckets and over 85% using weekly buckets compared to less than 50% using time-series techniques. Using the results of this extensive analysis, we propose a new forecasting model. We also identified additional factors that could not be included this analysis due to the lack of data; adding these to the model may further improve the forecast accuracy. / by Ahmed Rashad and Santiago Spraggon. / M.Eng.in Logistics

Thesis (S.M.)--Massachusetts Institute of Technology, Biological Engineering Division, 2004. / Includes bibliographical references (leaves 35-40). / The study of stem cells is one of the most fascinating topics in biology. Adult stem cells (ASC), which play the prime role in the maintenance and restoration of tissues, are thought to hold great potential for the advancement of medicine. It has been postulated that adult stem cells are able to retain "immortal" DNA template strands over successive generations by non-random chromosome co-segregation, and in so doing, to protect the long-term genomic fidelity of whole tissue compartments. The investigation of this theory may yield insights into areas such as the development of cancer and the process of aging. In addition, it may lead to the discovery of an effective method for the unique identification of adult stem cells, the study of which has thus far suffered from the lack of unique identifiers. Thus, the goal of this research was to develop an assay for the detection of immortal DNA strand co-segregation that could be applied to the detection and analysis of adult stem cells. It is proposed that such an assay may in itself serve as a unique identification method for adult stem cells. In this thesis, the development of such an assay is described. This assay, referred to as the label release assay, has provided further evidence for the existence of immortal strand co-segregation in model cell lines, and will potentially be useful in the study of adult stem cells in tissues. / by Jennifer J. Cheng. / S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Biological Engineering Division, 2007. / Includes bibliographical references (p. 111-127). / To shed light on the cell's response to its mechanical environment, we examined cell rheology at the single cell level and quantified it with nanometer spatial and microsecond temporal resolutions over a five-decade frequency range (- 0.5 Hz to 50 kHz). To this end, we developed and optimized an instrument for fast fluorescence laser tracking microrheology (FLTM). This novel method aims at experimentally deriving cellular viscoelastic properties from the passive monitoring of fluorescent microspheres undergoing Brownian motion inside the tested sample. Further instrument enhancement even broadens the FLTM frequency span up to seven decades by modulating data acquisition speed or complementing FLTM with a two-particle microrheology modality. In living cells, FLTM accurately characterizes the solid-like vs. liquid-like cytoskeletal behavior from measurements based on endocytosed micron-sized beads, independently of probe size or surface chemistry. FLTM also demonstrates the existence of two distinct rheological regimes on the cell surface and in the cell interior: While the former surface investigations show power-law frequency variations of the complex shear modulus G*(co), the latter intracellular experiments identify multiple time and length scales affecting cell rheological features. Finally, FLTM evaluates frequency-specific stretch-induced cell mechanics and thus promises to broaden and diversify the scientific knowledge on mechanotransduction, from a molecular and cellular standpoint. / (cont.) FLTM also demonstrates the existence of two distinct rheological regimes on the cell surface and in the cell interior: While the former surface investigations show power-law frequency variations of the complex shear modulus G*(co), the latter intracellular experiments identify multiple time and length scales affecting cell rheological features. Finally, FLTM evaluates frequency-specific stretch-induced cell mechanics and thus promises to broaden and diversify the scientific knowledge on mechanotransduction, from a molecular and cellular standpoint. / by Maxine Jonas. / Ph.D.

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2007. / Includes bibliographical references (leaves 84-89). / Ethanol can be made from agricultural residues like wheat straw and from crops dedicated to energy use, like switchgrass. We study the logistics aspects of this transformation and determine the main characteristics of the supply chain making ethanol from cellulose. Important to the final acceptability of ethanol as a transportation fuel is both the economics as well as the environmental aspect of using ethanol. In this study we analyze the buildup of cost as biomass is transformed into fuel. We also look at all the steps involved and describe them from a supply chain perspective We have found that the main cost components in the cellulosic ethanol production are biomass production, harvesting and ethanol refining. We have also found that the main factor in reducing the overall production cost is the biomass to ethanol conversion factor. The development of new technologies to convert biomass into ethanol becomes a critical issue to achieve the cost targets imposed in order to make ethanol more competitive with other sources of energy such as fossil fuels. An increase in the current conversion factor of 42% could potentially yield to a decrease of nearly 15% in the: total production cost of cellulosic ethanol. / (cont.) Other factors such as increasing the refining plant size and biomass yield can also help to reduce the production cost but we found its impact to be lower than that of the conversion factor. Finally, we also performed a strategic analysis of the entire supply chain to determine how is this industry likely to develop and who will have more bargaining power and therefore will realize most of the value and profits in the supply chain. Our analysis shows that in such a dynamic scenario as in the alternate energy industry, the best option is to build sustained advantage by strong alliances with different partners within the supply chain. / by Anindya Banerjee [and] José Luis Noguer. / M.Eng.in Logistics

Thesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2010. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 61-63). / The Lean Enterprise Self Assessment Tool (LESAT) is a product of the Lean Advancement Initiative (LAI) and the Massachusetts Institute of Technology. This tool has been applied by many organizations to gage their progress toward lean enterprise management, however applying this tool in health care organizations has been inhibited by language and underlying assumptions from product manufacturing. An adaptation of the LESAT specifically for health care is proposed. Review of the literature and special reports on health care are used in determining the recommended changes. "Product life cycle" is reinterpreted as a health care service cycle and context specific enterprise level processes and practices are presented. Comparison to other industry measures shows the content the LESAT for health care to cover all key issues and practices for high quality health care delivery. / by Cynthia Lynn Hernandez. / S.M.in Engineering and Management

Thesis (M. Eng. in Logistics)--Massachusetts Institute of Technology, Engineering Systems Division, 2006. / Includes bibliographical references (leaves 62-63). / In this thesis we consider a manufacturing and distribution supply chain of a roll-based product whose width comes in 1-cm increments. We formulate a computer model subject to stochastic, inelastic demand to determine the relationship between width interval and finished goods inventory levels. Assuming that the supply chain operates with the same set of policies regardless of the width interval value, we illustrate that the value of risk pooling diminishes as the interval widens. Due to the presence of a counteracting effect, we also demonstrate that increasing the width interval does not always reduce the amount of inventory requirements. Lastly, we show that the supply chain can operate with lower inventory levels without compromising the service level by pushing the inventory down the chain. / by Ying-Lai (Chandler) See [and] Jin Namkoong. / M.Eng.in Logistics

Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, September 2006. / Includes bibliographical references (leaves 64-68). / This work presents a look at real-life production-floor scheduling, comparing and contrasting it to both normative OR theory and Cognitive Psychology theory. Relevant literature in OR, scheduling and psychology is reviewed, and gaps in theory are pointed out, calling for observation of real-life scheduling and for modeling of the cognitive processes underlying such activities. While normative theory and cognitive psychology theory suggest certain behaviors should be observed, a case study conducted with a large manufacturing company reveals real-life scheduling to be different from behavior expected by OR as well as by cognitive psychology. Future research is suggested, which may enable better modeling of human schedulers. / by Yishai Boasson. / S.M.