Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2009. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 145-159). / Satellites have become a critical component of nearly every aspect of modern life. In addition to well-known civilian applications, military applications of space-based platforms include supporting mission operations through communications; intelligence, surveillance and reconnaissance (ISR); and position, navigation and timing (PN&T). While satellite applications are numerous and increasing technical achievements make satellites more capable, they do have several drawbacks. Satellites are expensive, they require long development times and they are difficult to replace. Since the successful Chinese anti-satellite (ASAT) missile test on January 11, 2006, U.S. military leaders have become increasingly concerned over this new vulnerability to critical space assets. In addition to efforts designed to improve operationally responsive space capabilities, military leaders have begun researching alternatives to space-based platforms. In November, 2006, the U.S. Army released the Army Space Master Plan (ASMP). In the unclassified extract of that plan, the Army identifies a list of eight topics for further investigation including the question, "Where should the Army invest in near-space and high-altitude, long-endurance [HALE] platforms as a lower cost, more responsive alternative to space platforms if they prove technically feasible?" This thesis discusses technical challenges associated with making HALE platforms feasible and explores the potential benefits of using these platforms to augment or enhance the three primary military applications of communications, ISR and PN&T including a detailed examination of current satellite-based military payload capabilities and limitations. / (cont.) Finally, this thesis discusses potential methods to integrate HALE capabilities into the current U.S. Army Space Operations doctrine and provides some suggestions for the potential role of Army Space Operations in the design, development, implementation and use of HALE systems. By demonstrating how the Army can use HALE platforms to reduce the capability gap and fulfill more of the users' requirements, this research will answer the question posed in the Army Space Master Plan. / by William Everette Symolon. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 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. 67-72). / This study estimates the impacts of commercial aviation noise at 181 airports around the world. These airports are located in 38 countries plus Taiwan, with 95 of the airports located in the United States. They are part of the 190 Shell 1 airports in the FAA's Model for Assessing Global Exposure to the Noise of Transport Aircraft (MAGENTA), which comprise an estimated 91% of total global aviation noise exposure [FAA 2008]. The model calculates both physical and monetary impacts of aviation noise. The physical metrics are the number of people exposed to 55 dB or more noise, and the number of people highly annoyed. The model uses a noise depreciation index developed from hedonic pricing studies of housing transactions to monetize the effects on property owners in terms of housing value loss and rent changes. Due to data collection difficulties the impacts are only approximately consistent chronologically. Population data are from the years 2000 and 2001 depending on the country, while house prices and rents are 2006 estimates, and noise levels are for the year 2005. Based on there data, we calculated that around the 181 airports more than 14 million people are exposed to at least 55 dB of commercial aviation noise. Of these individuals, approximately 2.3 million are highly annoyed. We found that the noise resulted in a total of $21 billion of housing value depreciation, which is equivalent to about $1.1 billion per year using a 30-year life of the house and a 3% discount rate, and an additional $800 million of lost rent each year. The impacts are spread over all parts of the world. Although most of the airports included in this study are located in the US and Europe, each continent with an airport in the study had airports with greater than $100 million in housing value loss and greater than 200,000 exposed people. / (cont.) Furthermore, North America, Europe, and Asia each had examples of airports with an estimated $80 million in annualized housing value loss ($1 billion total), 400,000 people exposed to 55 dB, and $25 million in yearly lost rent. We also examined potential changes to these impacts in the future for a scenario with no technological or operational advances to reduce noise (with the exception of retirement of older aircraft in the fleet). Based on an assumption of 2-3% annual growth rates in operations at these airports between 2005 and 2035 with no noise-technology improvements, we found that the undiscounted housing value and rent loss could approximately double by 2035 while the population exposed to 55 dB and highly annoyed could increase by about 70%. These results demonstrate the potential gains from further advances in aircraft technology and operations to mitigate community noise. / by Christopher KIsh. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2001. / Includes bibliographical references (p. 79-80). / by David L. Ferris. / S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1987. / Bibliography: leaves 217-229. / by John S. Langford, III. / Ph.D.

Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2018. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Cataloged from student-submitted PDF version of thesis. / Includes bibliographical references (pages 57-63). / Asia-Pacific anthropogenic emissions have changed rapidly in recent years due to industrialization, increasing mobility, and emissions controls. Although these changes have altered the region's burden of premature mortalities due to ambient fine particulate matter (PM₂.₅), the contribution of each sector and effectiveness of different policy measures has not yet been quantified. Such data would inform future decision-making on both policy effectiveness and the relative importance of controlling emissions from different sectors. This study estimates changes in regional anthropogenic emissions by industrial sector between 2010 and 2015, based on sector-level activity indicators and enacted emission controls. These factors are applied to an existing high-resolution emissions inventory for 2010 to estimate emissions up to 2015. Using a chemical transport model, the effects of changes in each sector's contribution to total PM₂.₅-driven premature mortalities are calculated for 2010 - 2015, in addition to the total contribution of each sector to premature mortality in 2015. 2,000,000 (95% CI: 1,740,000-2,260,000) annual global PM₂.₅-driven premature mortalities are attributed to Asia-Pacific anthropogenic sectoral emissions in 2015. The agricultural, industrial, and residential sectors constitute the top three sources of these total impacts. Between 2010 and 2015, sustained economic and activity growth, particularly in South and Southeast Asia, have led to 129,000 (95% CI: 106,000-166,000) additional annual premature mortalities, primarily across India, Indonesia, and Bangladesh. The energy and industrial sectors, in particular, cause 38,000 and 45,000 additional annual premature mortalities across these three countries respectively. Simultaneously, falling activity rates in other countries due to structural changes such as electrification of railroads, as well as newly introduced abatement measures over this period, including China's Action Plan on the Prevention and Control of Air Pollution as well as region-wide adoption of Euro IV/V/VI-compliant road vehicle emission and fuel quality standards have led to a total reduction of 95,000 (95% CI: 76,000-129,000) annual premature mortalities, primarily across East Asia, including China and Japan. These opposing drivers result in a net change of an additional 34,000 (95% CI: 23,000-47,000) PM2.5-driven annual premature mortalities between 2010 and 2015 due to Asia-Pacific anthropogenic emissions. / by Kingshuk Dasadhikari. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1989. / GRSN 406710 / Includes bibliographical references (leaves 146-147). / by Robert J. Polutchko. / M.S.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2014. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 175-184). / This thesis presents new insights and techniques for the analysis and design of autonomous or technology-assisted ("intelligent") transportation systems. The focus is on cooperative, on-line planning and control, of a fleet of transport vehicles with limited carrying capacity, where new transportation demands enter the system in real time. The study extends an existing probabilistic framework which has provided numerous insights about vehicle scheduling and routing problems since its inception. Additionally, the thesis provides algorithms and new probabilistic cost bounds, for optimal bipartite matchings between large sets of random points and optimal stacker crane tours through large sets of random demands. A recurrent theme of the thesis is that capacity-constrained vehicles must drive passenger-less, inescapably, for some positive fraction of time (in almost any practical setting). Moreover, under probabilistic modelling for the uncertainty of demand, one can predict the aforementioned fraction precisely, using strong Laws of Large Numbers arguments; it relates to a quantity known as the Earth Mover's distance (EMD), described by a fundamental problem in transportation theory. Since the existence of an unavoidable extra cost term has significant implications, e.g., for operational budgets of shared-vehicle systems, the results illuminate a phenomenon whose neglect could prove an unfortunate oversight. To the author's knowledge, this connection of the EMD to on-line vehicle routing is novel. The thesis also provides a new study of the practical considerations imposed by the "street rules" ubiquitous among ground-based transport problems. A new efficient algorithm for the Bipartite Matching problem for points on a roadmap is given. Also given is a new explicit formulation of the EMD on road networks; very few explicit formulas for EMDs have been known previously. / by Kyle Treleaven. / Ph. D.

Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 131-133). / The Hybrid Shell Model (HSM) is presented as an intermediate-fidelity structural model well suited for conceptual design of aerospace vehicles. Although significantly simpler and more economical than full 3D elasticity models, it can still capture full 3D geometries, large deformations, and anisotropic materials. HSM is formulated from the full 3D equilibrium and compatibility equations all projected onto local bases defined on the 2D shell manifold. General anisotropic constitutive equations are also formulated in the local 2D shell manifold bases. The resulting continuous HSM formulation is discretized in weak form with a Galerkin finite element method (FEM), with spherical interpolation used for the local basis vectors. Displacements, basis rotations, and stress resultants are the primary unknowns. A fully adjoint-consistent plane-stress HSM version (HSM2D) is developed for the purpose of model verification and demonstration of order-of-accuracy convergence. The Method of Exact Solutions (MES) is applied to the case of a uniform plate hanging under its own weight. The effectiveness of the adjoint model for structural optimization is also demonstrated for a simplified rotor blade in a centrifugal force field, featuring non-uniform forcing, non-zero Poisson ratio, large deflection, and optimization of multiple parameters. The suitability of HSM as an intermediate fidelity conceptual aircraft design tool is thus demonstrated. / by William Cooper Thalheimer. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1994. / Title as it appears in the June 1994 MIT Graduate List: Rotational effects of turbine cooling. / Includes bibliographical references (leaves 102-103). / by Pamela S. Barry. / M.S.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2004. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / "September 2004." / Includes bibliographical references (p. 73-75). / (cont.) The last experiment showed that individual subjects PER values changed over time intervals as short as ten minutes, and revealed the importance of the subject's prior experience in PER experiments. This suggests that limitations of working memory may effect the repeatability of the PER measure. The definition and measure of PER for each subject may also provide a means for quantifying the magnitude of a clinical condition known as oscillopsia, where we perceive the world as non-stationary, such as moving independently of our head motions. These findings are important for a perceptually sensitive environment, such as virtual reality. Designers of virtual environments that utilize self-motion perception should consider calibrating PERs within a session for each individual user and be aware that that the subject's calibration may change over time. / If we walk on a treadmill and are looking in the direction of motion of a moving virtual environment, the perceptions from our various senses are harmonious only if the visual scene is moving in a narrow range of speeds that are, typically, greater than our walking speed. This observation has been reported when we project a virtual environment through a display with a restricted field-of-view, such as a head-mounted display (HMD). When the subject feels that the scene-motion is natural for their walking speed, the ratio of the speed of his visual surround to that of the treadmill walking speed is defined as his perceptual equivalence ratio (PER) in that setting. Four experiments explored a set of conditions under which the PER measured on a treadmill is constant. The experiments, motivated by several hypotheses, investigated the relationship between PER and display type (HMD vs. either desktop monitor or on-screen projection), sense of presence in the virtual environment, and the magnitude of illusory self-motion (vection). We also investigated differences among subjects, and the stability of PER over time due to the limitations of working memory. Most experiments considered more than one hypothesis. The first two experiments found that PER was affected by the type of display used, but found no correlation of PER with the sense of presence reported by the subject. A third experiment showed that PER was nearly the same whether we manipulated visual or treadmill speed (and asked the subject to match the other.) While PER values were often constant versus treadmill speed for any individual subject, they were very different from subject to subject. PER appears to be relatively stable over a short test session, but may be highly variable over extended periods of time. / by Kevin R. Duda. / S.M.