http://hdl.handle.net/1721.1/7612 2013-05-19T20:42:37Z http://hdl.handle.net/1721.1/78541 Incorporating uncertainty in the Life Cycle Cost Analysis of pavements Swei, Omar Abdullah Life Cycle Cost Analysis (LCCA) is an important tool to evaluate the economic performance of alternative investments for a given project. It considers the total cost to construct, maintain, and operate a pavement over its expected life-time. Inevitably, input parameters in an LCCA are subject to a high level of uncertainty, both in the short-term and long-term. Under its current implementation in the field, however, LCCA inputs are treated as static, deterministic values. Conducting such an analysis, although computationally simpler, hides the underlying uncertainty of the inputs by only considering a few possible permutations. This suggests that although computationally simpler, the answer from the analysis may not necessarily be the correct one. One methodology to account for uncertainty is to treat input parameters as probabilistic values, allowing the analysis to consider a range of possible outcomes. There are two major reasons as to why probabilistic LCCAs, although recommended, have not been streamlined into practice. First, the LCCA of construction projects is a large-scale problem with many input parameters with a high-level of uncertainty. Second, there is a significant gap in research that statistically quantifies uncertainty for input values. This research addresses the latter point by statistically quantifying four types of uncertainty: the unit cost of construction, quantity of material inputs, occurrence of maintenance activities, and a particular emphasis is placed upon characterizing the evolution of material prices over time. Having statistically characterized uncertainty in the LCCA analysis, the application of the probabilistically derived inputs is illustrated in three scenarios. Pavement alternative designs are derived for a set of traffic conditions in a given location. The results of the analysis indicate the integration of probabilistic input parameters in the LCCA process allows for more robust conclusions when evaluating alternative pavement designs. Additionally, the case study shows treating input parameters probabilistically could potentially alter the pavement selection, and one parameter that greatly influences this is material-specific price projections. Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (p. 81-87). 2012-01-01T05:00:00Z http://hdl.handle.net/1721.1/78540 Exploring the value proposition of integrating back-up saline storage into anthropogenic CO₂ supplied EOR operations Toukan, Ibrahim (Ibrahim Khaled) Enhanced oil recovery (EOR) through carbon dioxide (CO₂) sequestration from anthropogenic sources has been gaining attention in policy circles. In particular, it is viewed as a potential way to help accelerate the deployment of carbon capture and sequestration (CCS) technologies. The interest in the EOR-CCS model stems from the economic, geologic and regulatory benefits this model offers when compared to the waste-driven CCS model that utilizes saline aquifers for CO₂ storage. However, there are still some major challenges impeding the deployment of the EOR-CCS model; chief among these challenges is the mismatch between CO₂ supplies from anthropogenic sources and CO₂ demand from EOR operations. One potential way to address this challenge is through a CO₂ stacked storage system. A CO₂ stacked storage system utilizes brine formations adjacent to EOR oilfields for the purpose of storing any additional quantities of CO₂ the EOR operation cannot handle. The concept of a stacked storage system with focus on CO₂ supplies from coal-fired power plants was analyzed using a case study. A U.S. coal-fired power plant and a U.S. EOR oilfield were used to model a stacked storage system in order to determine the economic and technical viability of such a model. More specifically, this thesis has three main objectives. The first is to determine the overall cost of implementing the stacked storage system. The overall cost of the system came to approximately $90 per ton of CO₂ avoided. Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (p. 83-85). 2012-01-01T05:00:00Z http://hdl.handle.net/1721.1/78515 The MQ-9 Reaper remotely piloted aircraft : humans and machines in action Cullen, Timothy M Remotely piloted aircraft and the people that control them are changing how the US military operates aircraft and those who fly, yet few know what "drone" operators actually do, why they do what they do, or how they shape and reflect remote air warfare and human-machine relationships. What do the remote operators and intelligence personnel know during missions to "protect and avenge" coalition forces in Iraq and Afghanistan and how do they go about knowing what they know? In an ethnographic and historical analysis of the Air Force's preeminent weapon system for the counterinsurgencies in the two countries, this study describes how social, technical, and cognitive factors mutually constitute remote air operations in war. Armed with perspectives and methods developed in the fields of the history of technology, sociology of technology, and cognitive anthropology, the author, an Air Force fighter pilot, describes how distributed crews represent, transform, and propagate information to find and kill targets and traces the observed human and machine interactions to policy assumptions, professional identities, employment concepts, and technical tools. In doing so, he shows how the people, practices, and machines associated with remotely piloted aircraft have been oriented to and conditioned by trust in automation, experience, skill, and social interactions and how they have influenced and reflected the evolving operational environment, encompassing organizations, and communities of practice. Thesis (Ph. D. in Technology, Management, and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology, Management, and Policy Program, 2011.; Cataloged from PDF version of thesis.; Includes bibliographical references (p. 290-298). 2011-01-01T05:00:00Z http://hdl.handle.net/1721.1/78504 The diffusion of innovations in the presence of geography and media Toole, Jameson Lawrence Increasingly, the world we live in is digital, mobile, and online. As a consequence, many of your seemingly mundane actions are recorded, archived, and for the first time widely accessible to both the generators and curators of this information. From this fire hose of digital breadcrumbs, we can learn an enormous amount about ourselves as individuals and societies. Simple questions such as where we go, who we are meeting, and how we interact when we get there can be explored with incredibly high resolution and richness. Through new emiprical and analytic tools, we can leverage information generated from rapidly expanding online social networks, revealing the beautiful and often surprising complexity of everyday human behavior. We are able to harness data from millions of cell phone users to better understand how people move through cities, use roads, and interact with their neighbors. This thesis deals with quantifying, analyzing, and ultimately modeling sociotechnical systems. More specifically, it focuses on modeling the diffusion of innovations in time and space. While there has been much work examining the affects of social network structure on innovation adoption, models to date have lacked important features such as meta-populations reflecting real geography or influence from mass media forces. This thesis shows that these are features crucial to producing more accurate predictions of a social contagion and technology adoption at the city level. Using data from the adoption of the popular micro-blogging platform, Twitter, a model of adoption on a network is presented. The model places friendships in real geographic space and exposes individuals to mass media influence. Results show that homophily both amongst individuals with similar propensities to adopt a technology and geographic location is critical to reproduce features of real spatiotemporal adoption. Furthermore, estimates suggest that mass media was responsible for increasing Twitter's user base two to four fold. To reflect this strength, traditional contagion models are extended to include an endogenous mass media agent that responds to those adopting an innovation as well as influencing agents to adopt themselves. The final chapter of this thesis addresses the future. The ubiquity of digital devices like mobile phones and tablets is opening rich new avenues of research. The massive amounts of data generated and stored by these devices can be used to gain a better understanding of the complex socio-technical systems they sense. The same tools, techniques, and analogies utilized in the first three chapters of this thesis can now literally be taken to the streets. With mobile phones that record when and where activities take place, a new window has been opened on urban systems. Future work will explore how people use cities dynamically to improve transportations systems and inform urban planners. New measurements will help understand what cities do well, when they fail, and why. At the core of this new domain, is an interdisciplinary approach to complex socio-technical systems that combines many fields and methods. This view forms a more holistic view of problems and potential solutions. The thesis presented stands as an example of data, theory, and simulation for diverse areas can be combined to gain novel insights into human behavior. Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (p. 101-105). 2012-01-01T05:00:00Z