Página 1 dos resultados de 1423 itens digitais encontrados em 0.064 segundos

‣ Quantifying technology infusion and policy impact on low earth orbit communication satellite constellations

Chang, Darren Datong, 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 204 p.; 10443811 bytes; 10468706 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
158.63985%
Technology infusion and policy implementation bring impacts to the trade space of complex engineering systems. This work describes in detail the frameworks for quantitative analyses on these impacts, demonstrates their use on the sample system, and presents the analysis results. The low earth orbit (LEO) communication satellite constellation system serves as the platform for carrying out the system trade space analysis. The system is reproduced in computer environment in the form of a multiple-input-output MATLAB model. The model contains multiple modules that incorporate the physics, economy, and policies of the real-world system. The inputs to the model are system design variables and the outputs are system performance, capacity, and cost. The Pareto optimal solution set of the baseline trade space is generated by the model using a full-factorial run that covers the entire design space. To simulate technology infusion, technical and cost attributes of four new technologies are quantified and infused into the system model. The infusion of technologies and combinations of technologies into the system is simulated. Policy implementation is simulated by changing the policy constraints in the model. The technology-infused trade space and policy-implemented trade space have new sets of Pareto optimal solutions. By comparing these solution sets with the baseline optimal solution set in the objective space...

‣ Aircraft emissions reductions through improved operational performance : challenges, opportunities and policy implications

Miller, Bruno, 1974-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 125 p.; 8269117 bytes; 8268874 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
158.30432%
by Bruno Miller.; Thesis (S.M.)--Massachusetts Institute of Technology, Technology and Policy Program, 2001.; "June 2001."; Includes bibliographical references (p. 119-125).

‣ Economic and policy implications of urban air pollution in the United States, 1970 to 2000

Yang, Trent, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 85 leaves; 4939452 bytes; 4948678 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
158.38612%
(cont.) over time as pollution levels change. Using these new models, we valued the economic benefit of reduced air pollution due to the Clean Air Act regulations to be over $7 trillion from 1970 to 2000, or 2.1% of aggregate US economic welfare over the period. This does not include the benefits into the future (after 2000) from reduction in mortality due chronic exposure during these years. The economic benefit of those saved mortalities is another $7 trillion using a 3% discount rate. Another calculation is the remaining economic burden of unmitigated pollution levels (actual historical pollution). We estimate this to be approximately $9 trillion over the same period. The $9 trillion burden includes the early mortalities due to chronic exposure to PM before and during this period. While these economic benefits of air pollution regulation are large ($7 trillion), they are considerably less than the $27.6 trillion estimated in EPAs own analysis of the benefits of air pollution regulation. The main difference for our lower estimate is the stock-flow accounting of mortality due to chronic exposure. There are considerable uncertainties in these estimates both because of uncertainties in the relationship between air pollution exposure and the health effects...

‣ Commercial and informal atmospheric emissions in the Mexico City Metropolitan Area : scenario analysis and policy proposals

Flores Montalvo, Andres, 1967-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 142 leaves; 6338883 bytes; 6338689 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
158.31049%
by Andres Flores Montalvo.; Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2003.; Includes bibliographical references (leaves 109-112).

‣ Grid computing : business and policy implications

Ong, Sze Hwei, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 86 leaves; 3303128 bytes; 3302936 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
158.30432%
by Sze Hwei Ong.; Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2003.; Includes bibliographical references (leaves 84-86).

‣ Political economy insights into the defense acquisition process : lessons from the Joint Strike Fighter Program

Hitchings, Sean, 1975-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 107 leaves; 7222086 bytes; 7221895 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
148.6099%
The military aircraft industry is a cornerstone of national security and of the economic health of the United States. The Joint Strike Fighter (JSF) program was sold as a solution to a host of needs, from advancing the capabilities of each Service, modernizing an aging fleet, countering sophisticated threats, enhancing inter-service cooperation, and implementing acquisition reform, all in a revolutionarily cost-effective way. Because of this tantalizing promise, the early JSF program was able to navigate through budgetary pressures while other aircraft programs were cancelled. This thesis argues that the JSF program is a manifestation of a collective action problem, wherein stakeholders, who should be providing a check on each other, are cooperating, even as the stakeholder who should be participating, remains uninvolved. Consequently, the acquisition policies brought in with the JSF program are not improving acquisition policy, but are exacerbating the inefficiencies to which the U.S military acquisition system has historically been prone. This analysis provides insight into how to improve the technology policies governing military aircraft acquisition, and the supply of aircraft to other nations. This analysis is geared for senior policy makers in both government and industry...

‣ Telecommunication technologies development in countries of the former Yugoslavia : history, needs and policy options for the future

Sulejmanpašić, Adnan, 1976-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 90 p.; 4760988 bytes; 4765538 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
158.38246%
In the first part of this thesis I give an overview of the political-economic and telecommunications sector developments in major western economies, as well as some of the advanced Eastern European countries. I use this framework to analyze the telecommunications sector development in countries of the former Yugoslavia: Bosnia and Herzegovina, Croatia, Macedonia, Serbia and Montenegro. Here I address the relevant legal and regulatory landscape development as well as the entrance of the most important business actors in the telecommunications markets of these countries. The history of the telecommunications sector development is also placed in the context of a broader set of political and economic shocks that affected this region of the world after the fall of the Iron Curtain. Throughout the thesis I build on insights learned during the research internship project that I undertook this summer: I visited capitals of all the former Yugoslavian countries and gathered data relevant to the telecommunications sector development by interviewing government and business sector officials there. This information is heavily used for the derivation of a set of policy recommendations and options that government officials should consider for advancing the development of the telecommunications technologies in the countries of the former Yugoslavia. Strategies for telecommunications sector development...

‣ Portfolio evaluation of advanced coal technology : research, development, and demonstration

Naga-Jones, Ayaka
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 134 p.; 46638943 bytes; 46638443 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
148.63434%
This paper evaluates the advanced coal technology research, development and demonstration programs at the U.S. Department of Energy since the 1970s. The evaluation is conducted from a portfolio point of view and derives implications for future program design and implementation. The evaluation framework consists of four categories of criteria that assess the portfolio from strategy, diversity, partnership, and project merit points of view. The analysis of the successes and the failures of the past programs in technical, financial and managerial respects shows that these programs are reasonably successful in (1) remarkably advancing coal technologies to enable the U.S. to use coal as its major energy resource in the electricity sector when facing more stringent environmental regulation or possibly even in a greenhouse gas constrained world; (2)accumulating effective program management experience, especially involving industry in technology development from the beginning of the process to facilitate future deployment. Among these successes, a number of important features incorporated in the CCTDP are especially worth noting. These features are: (1) The program goal was well defined, which was accelerating commercialization of ACTs;; (cont.) (2) All projects have been fully funded up front...

‣ Changes in the characteristics of new drug applications for the treatment and prevention of diabetes mellitus

Lin, Hsiao-Lan Sharon
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 183 p.
Português
Relevância na Pesquisa
148.62936%
Efforts in managing diabetes, including the medical advances in novel therapies and public health policies of disease control and prevention, have not reduced the disease prevalence since 1990s. I analyze this phenomenon from the technology and policy viewpoints underlying diabetes treatment and prevention, in order to control and manage the disease in a cost-benefit balanced manner. The innovative performance of the antidiabetic drug therapy is investigated by analyzing the fifteen New Drug Applications (NDAs) of the antidiabetics approved by the US Food and Drug Administration since the early 1990s. I examine the characteristics of the clinical trials supporting NDAs and observe how the complexity of clinical trials has changed over time. Nine out of the twenty-five selected indicators are found to exhibit an increasing trend of complexity. The trend is more pronounced in the oral antiglycemics group (seven indicators) than the subcutaneous group (two indicators). Interestingly, this trend in increasing complexity in clinical trials is generally consistent with that of the increasing R&D costs in the pharmaceutical industry, possibly account for the declining innovative performance of the industry over the time period under investigation. A system dynamics approach is applied to assess current public health policies in diabetes control and prevention.; (cont.) The benefit of system thinking is to avoid potential policy resistance by identifying the problematic characteristics of the system...

‣ Revenue Management in the railway industry in Japan and Portugal : a stakeholder approach; RM in the railway industry in Japan and Portugal : a stakeholder approach

Abe, Itaru, S.M. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 133 leaves
Português
Relevância na Pesquisa
158.44975%
Revenue Management (RM) is the process of managing the sales of perishable assets by controlling price and inventory so as to maximize profit. It was developed in the late 1970s after the deregulation of the US airline industry, and has enabled the US airline industry to increase its revenue by offering dynamic prices associated with demand. Many academic articles have understandably focused on applications to the airline industry. This thesis deals with the application of RM to the railway industry. The railway is considered the most energy-efficient mode of transportation, and its role has become increasingly important around the world with ever growing concerns about the global energy crisis and climate change. Implementing an RM strategy for railways is expected to contribute to a significant lessening of this environmental burden by making better use of the existing railway infrastructure. Furthermore, it is not only advantageous for the railway operators, but also for the passengers who can benefit from discounted tickets. In fact, several countries have already introduced RM to their railway systems. However, the results have not always turned out as desired and the goals set out by the policy makers have not always been achieved.; (cont.) Most research looking at the issue of how RM should be applied to the railway industry has employed a quantitative approach. While the development of mathematical models is clearly valuable...

‣ Analysis and calibration of social factors in a consumer acceptance and adoption model for diffusion of diesel vehicle in Europe

Zhang, Qi, S.M. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 63 p.
Português
Relevância na Pesquisa
158.26547%
While large scale diffusion of alternative fuel vehicles (AFVs) is widely anticipated, the mechanisms that determine their success or failure are ill understood. Analysis of an AFV transition model developed at MIT has revealed that AFV diffusion dynamics are particularly sensitive to consumer consideration as influenced by social exposure to AFVs. While some empirical research in this area exists, uncertainty regarding these social exposure parameters remains high. Following principles of partial model testing, this research examines social exposure parameters, with a focus on empirical accounts of diffusion involving diesel passenger vehicles in Europe. The research uses the historical data of diesel sales in six European countries. To complete diffusion datasets the research generates synthetic data in early stages of diffusion. The results from the calibrations yield parameters that are in line with other marketing studies. These findings help reduce uncertainty regarding social exposure parameters in the automotive industry. Further, bootstrapping confidence intervals are conducted to test the reliability of the parameter estimate. Challenges and avenues about building confidence in parameter estimate and data analysis are discussed.; by Qi Zhang.; Thesis (S.M.)--Massachusetts Institute of Technology...

‣ Building a national technology and innovation infrastructure for an aging society

Lau, Jasmin
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 192 p.
Português
Relevância na Pesquisa
158.5559%
This thesis focuses on the potential of strategic technology innovation and implementation in sustaining an aging society, and examines the need for a comprehensive national technology and innovation infrastructure in the U.S., capable of supporting the development and use of technologies by the aging population and their caregivers. The pervasiveness of population aging makes it a primary concern for nations around the world today. As the inadequacies of existing resources become apparent, policy makers .are now turning to technology and innovation to cope with the changing demographics. 'Technological innovations to accommodate the elderly have existed since centuries ago, and they been useful in extending the human capability beyond perceived limitations of aging. However, new technologies developed with the same objectives are not widely adopted and accepted by the aging population today. The thesis is divided into two complementary sections.; (cont.) The first examines three hypotheses for the slow penetration rates of new technologies for aging: 1) Useful, affordable and usable technologies are unavailable, 2) Professional carers that can play a catalytic role between technological innovation and implementation are not technologically educated and prepared to incorporate the technologies into elderly care...

‣ Integrating automobile multiple intelligent warning systems : performance and policy implications

Ho, Angela Wei Ling
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 167 p.
Português
Relevância na Pesquisa
158.33404%
Intelligent driver warning systems can be found in many high-end vehicles on the road today, which will likely rapidly increase as they become standard equipment. However, introducing multiple warning systems into vehicles could potentially add to the complexity of the driving task, and there are many critical human factors issues that should be considered, such as how the interaction between alarm alerting schemes, system reliabilities, and distractions combine to affect driving performance and situation awareness. In addition, there are also questions with respect to whether there should be any minimum safety standards set to ensure both functional and usage safety of these systems, and what these standards should be. An experiment was conducted to study how a single master alert versus multiple individual alerts of different reliabilities affected drivers' responses to different imminent collision situations while distracted. A master alert may have advantages since it reduces the total number of alerts, which could be advantageous especially with the proliferation of intelligent warning systems. However, a master alert may also confuse drivers, since it does not warn of a specific hazard, unlike a specific alert for each warning systems.; (cont.) Auditory alerts were used to warn of imminent frontal and rear collisions...

‣ Driving segments analysis for energy and environmental impacts of worsening traffic

Feng, Wen, Ph. D. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 185 p.
Português
Relevância na Pesquisa
158.33293%
During the last two decades, traffic congestion in the U.S. has increased from 30% to 67% of peak period travel. Further, current research shows that measures taken within transportation systems, such as adding capacity, improving operations and managing demand, are not enough to keep congestion from growing worse. With the worsening traffic, the vehicle's fuel consumption and pollutant emissions will inevitably increase. As such, this thesis aims to quantitatively evaluate the energy and environmental impacts of worsening traffic on individual vehicles and the U.S. light-duty vehicle fleet, as well as to design feasible measures beyond transportation systems to offset theses impacts. The fuel consumption and emissions of different vehicle types under different driving situations provide the basis for analyzing the energy and environmental impacts of worsening traffic. This thesis defines the concept of "driving segments" to represent all possible driving situations which consist of vehicle speed, operation patterns and road types. For each vehicle type, its fuel consumption and emissions in different "driving segments" can be developed into a matrix by ADVISOR 2004, the vehicle simulation tool. Combining the "driving segments" vehicle performance matrices with the model for traffic congestion...

‣ Technology and policy drivers for standardization : consequences for the optical components industry

Speerschneider, Michael James, 1975-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 145 p.; 10230428 bytes; 10248278 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
168.4504%
Optical communications promise the delivery of high bandwidth service to all types of customers. The potential for optical communications is enormous and has generated excitement and anticipation over the last decade. However, the emergence of a growing market has not materialized and the 1990s communications "bubble" has burst. One result of the bubble burst is that manufacturers of optical components have seen demand for their products plummet and are now struggling to survive. The future of the communications industry depends on its ability to provide better services and higher reliability. At some point, the upward curve of communications demand will require a strong optical components industry to support the industry. If the current stagnation continues, and the manufacturers fail, the economic pillar that is communications will suffer. The MIT Microphotonics Center has initiated a Communications Technology Roadmap study to better understand the technical, economic, and political factors that are inhibiting growth in the optical communications industry. This thesis examines the current state of the optoelectronic manufacturing industry and the causes of the decline. The primary focus is the rampant proliferation of optical transceiver designs resulting from abnormal market conditions during the "boom years" of the 1990s. The transceiver provides send/receiver capabilities and is the major component of optical networks. Convergence...

‣ Managing global software development teams : technology and policy proposals for knowledge sharing

Seshasai, Satwiksai, 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 97 leaves; 5688748 bytes; 5693778 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
168.52307%
This thesis uses an in-depth case study, with integrated data analysis, to compare and contrast globally distributed and co-located software teams within the IBM Corporation. Important differences in information sharing, collaboration and other behaviors were observed, along with a range of innovations in work operations. Technology and policy implications that draw on the benefits of each model are identified. The development of this thesis began with a seminar that was conducted at MIT to invite stakeholders in various areas of knowledge-based offshore outsourcing to discuss strategic, economic, organizational and technical issues raised in various environments. Large and small firms, various industries, and various business models were covered. The context provided by these stakeholders was used to design an in-depth case study at IBM, with the focus on a matched pair of software teams, which were studied for a period of one year. Both software teams were identical in aspects such as product scope, team size and domain; however, they differed in the key aspect that one team's members all work on the same hallway while the other team's members are geographically dispersed among multiple locations in the United States and India Quantitative technical data from the source control system of each team...

‣ Voice over Internet Protocol (VoIP) : the dynamics of technology and regulation; VoIP : the dynamics of technology and regulation

Vaishnav, Chintan
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 166 p.; 7589104 bytes; 7596073 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
158.41029%
"What Voice over Internet Protocol (VoIP) is going to do is start to weaken the foundation of the way we've done things for 100 years...Congress already should be discussing the next telecom bill," said Federal Communications Commission (FCC) Chairman Michael Powell in February 2004, before the United States Senate. The objective of this thesis is to study how VoIP challenges the incumbent US telecommunications act. The appearance of VoIP comes at a juncture when telecommunications system has already turned into a large-scale, complex system with multiple, competing infrastructures. VoIP, however, greatly augments the nested complexity by affording a technology that enables multiple architectures and business models for delivering the same voice (and often converged voice and data) service, while remaining agnostic to the underlying infrastructure. The VoIP-enabled architectures have very different capabilities and costs from one another. Many do not - or cannot - support social regulations such as emergency 911, wiretapping and disability access. Most exploit the economic arbitrage opportunities by evading access charges and universal service contributions.; (cont.) Added to this is the combination of reduced asset specificity due to VoIP's layered architecture and a global standard based ubiquitous IP technology that frees the service providers of the need to own the delivery infrastructure...

‣ Assessing the technical, economic and policy-centered feasibility of a proposed satellite communication system for the developing world

Samuels, Ayanna Terehas
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 217 p.; 11571112 bytes; 11585349 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
158.52203%
Satellite communication systems remain one of the most under utilized development mediums in less industrialized countries. This research proposes to establish a low cost satellite communications system tailored specifically for the developing world (+/- 30⁰ latitude). The technical, economic and policy related frontiers of the problem are integrated within a MATLAB based satellite communication constellation simulation which is used to assess the feasibility of the proposed satellite system. The analysis demonstrates that with technical advances that would allow higher capacity systems at lower costs and a renewed policy framework in line with the present state of the satellite system industry, it could be feasible to establish a low earth orbit satellite communications system for the developing world. The inputs to the satellite simulation are the proposed system's desired design variables and other relevant parameters. The outputs are system performance, capacity and cost. The Pareto optimal solution trade space is generated by the simulation model using a full-factorial run that probes the entire design space. The application of choice is short messaging services (SMS), chosen for its ability to provide proven connectivity at moderate costs. The capacity and cost of the most ideal Pareto architecture is contrasted against demand in the defined developing world region. The simulation also accounts for the necessary policy considerations and assesses the feasibility of the proposed system amidst the existing industry policy and regulatory framework. Additionally...

‣ Civilian applications and policy implications of commercial unmanned aerial vehicles

Sprague, Kara Lynn, 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 52 leaves; 902303 bytes; 1188213 bytes; application/pdf; application/pdf
Português
Relevância na Pesquisa
158.38073%
As UAV capabilities continue to improve the technology will spill out of the military sector and into commercial and civil applications. Already, UAVs have demonstrated commercial marketability in such diverse areas as scientific and environmental research, cross-seas shipping, communications relays, emergency management, border monitoring, agriculture, and aerial photography. Small-scale tactical UAVs in particular have an enormous potential to fulfill a number of roles within urban centers, transforming the way civil safety institutions carry out their jobs. A lack of established flight regulations is currently the greatest barrier to the standardized use of these vehicles. While the United States is currently the world's leader in UAV manufacturing, this position is tenuous given strong competitive threats from a variety of foreign countries who are already ahead in establishing a standardized regulatory environment for UAVs. As part of a larger research effort focused on the design, implementation, and demonstration of highly maneuverable rotorcraft UAVs, the primary objective of this work is to examine how UAVs might gain access to and function safely in civil and commercial markets. Despite the wide variety of existing UAVs in terms of size...

‣ Environmental technology and policy development in a regional system : transboundary water management and pollution prevention in southeastern Europe

Electris, Christi
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 270 p.
Português
Relevância na Pesquisa
168.64514%
In order to surmount the barriers to transboundary integration and coordination of environmental technology and regulatory policy in Southeastern Europe, the environmental capabilities and needs of the region are discussed, and a regional cooperation and coordination systems framework is developed. The thesis focuses on a case study of transboundary water resource management of the Mesta/Nestos River Basin between Bulgaria and Greece is presented in order to understand the coordination problems between a particular locality's level of integration in environmental technology development and use, and environmental regulatory policy, as well as the barriers to cooperation between two localities sharing a transboundary resource. For the case study, the physical characteristics and environmental stresses on the basin are described in detail. Next the policy governing local water resource management and environmental technology development is reviewed in terms of national laws and regulations, the bilateral diplomatic agreements, and the EU framework that drives much of the current activity in the basin today. Finally, the gaps in current policy and the barriers to coordinating water resource-related technology policy and environmental regulatory policy development are analyzed. The end result is a set of recommendations pertaining to the particular basin...