Página 27 dos resultados de 2122 itens digitais encontrados em 0.030 segundos

‣ Modeling carbon dioxide particle releases in the deep ocean; Modeling CO₂ particle releases in the deep ocean

Wannamaker, Eric J. (Eric Joseph), 1975-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 97 p.; 767216 bytes; 766935 bytes; application/pdf; application/pdf
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by Eric J. Wannamaker.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2002.; Includes bibliographical references (p. 93-97).; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.

‣ Modeling airline passenger choice : passenger preference for schedule in the passenger origin-destination simulator (PODS)

Carrier, Emmanuel, 1973-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 136 leaves; 1734269 bytes; 1734117 bytes; application/pdf; application/pdf
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by Emmanuel Carrier.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.; Includes bibliographical references (leaves 135-136).; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.

‣ Localization of nonlinear water waves over a random bottom

Grataloup, Géraldine Léonie, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 90 p.; 4617201 bytes; 4616953 bytes; application/pdf; application/pdf
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by Géraldine Léonie Grataloup.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.; Includes bibliographical references (p. 87-90).; This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.

‣ Managing the development of the real estate portfolios of state transportation authorities in the Boston area

Tsipis, Yanni Kosta, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 111 leaves; 7800950 bytes; 7800758 bytes; application/pdf; application/pdf
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by Yanni Kosta Tsipis.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2002.; Includes bibliographical references.

‣ Calibration of a microscopic traffic simulator

Kurian, Mathew, 1976-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 90 leaves; 6360267 bytes; 6360025 bytes; application/pdf; application/pdf
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by Matthew Kurian.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.; Includes bibliographical references (leaves 88-90).

‣ Outlining a future of suply chain management-coordinated supply networks

Hoppe, Richard M. (Richard Martin), 1976-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 157 p.; 13988825 bytes; 13988582 bytes; application/pdf; application/pdf
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by Richard M. Hoppe.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001.; Includes bibliographical references (p. 149-157).

‣ Development of a dynamic traffic assignment system for short-term planning applications

Sundaram, Srinivasan, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 147 p.; 9967094 bytes; 9966849 bytes; application/pdf; application/pdf
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by Srinivasan Sundaram.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2002.; Includes bibliographical references (p. 141-147).

‣ Simulation tools for microelectromechanical systems; Simulation tools for MEMS

Ramaswamy, Deepak, 1974-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 104 leaves; 5760284 bytes; 5760038 bytes; application/pdf; application/pdf
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by Deepak Ramaswamy.; Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001.; Includes bibliographical references (p. 101-104).

‣ The effects of carpet dye on the Bagmati River

Green, Hillary Monette, 1981-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 69 leaves; 7319297 bytes; 7319057 bytes; application/pdf; application/pdf
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by Hillary Monette Green.; Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2003.; Includes bibliographical references (leaves 67-69).

‣ Observability of Origin-Destination matrices for Dynamic Traffic Assignment; Observability of O-D matrices for DTA

Gupta, Ashish, S.M. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 148 p.; 7178313 bytes; 7184499 bytes; application/pdf; application/pdf
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The estimation of dynamic Origin-Destination (O-D) matrices from aggregated sensor counts is one of the most important and well-researched problems in Dynamic Traffic Assignment (DTA) systems. In practice, more often than not, number of sensors are far less than the number of potential O-D pairs, and hence this problem is modeled in an optimization framework as function of historical estimates of O-D flows. However, in the absence of reliable historical O-D flows, it is critical that O-D estimation module is observable. Observability is defined as a property of the system by which it is possible to uniquely determine the (initial) state (O-D flows) of the system eventually by making regular indirect measurements of the state. In DTA systems, observability implies that given enough sensor data, it is possible to uniquely determine O-D flows without any prior information about them. This thesis develops a methodology to verify the observability property of the O-D estimation model given limited sensor coverage on the network. A case study involving a large-scale network from Los Angeles, California is used to demonstrate the feasibility of the proposed approach.; (cont.) A comprehensive off-line calibration exercise for the same network is then used to verify the validity of the conclusion.; by Ashish Gupta.; Thesis (S.M.)--Massachusetts Institute of Technology...

‣ Water demand management in Kuwait

Milutinovic, Milan, M. Eng. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 91 leaves; 4121720 bytes; 4125474 bytes; application/pdf; application/pdf
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Kuwait is an arid country located in the Middle East, with limited access to water resources. Yet water demand per capita is much higher than in other countries in the world, estimated to be around 450 L/capita/day. There are several reasons for such a high demand, but one is certainly the price. Water does have its pricing schedule in Kuwait, but in reality water bills are not collected. The main objective of this thesis is to investigate the impact of water pricing as a tool for managing water demand. The original idea, to construct a water demand model for Kuwait, was modified because of the lack of data about the effect of price increases and household water consumption characteristics in Kuwait. So, water demand models described in the literature for several arid regions were adapted and recalibrated for Kuwait. Simulations describing the influence of block tariffs, constant prices, free allowances followed by various pricing schemes were conducted. A pricing schedule has been proposed that consists of a free allowance followed by a constant price. The proposal has the following logic: if water is consumed wisely, only to satisfy vital needs, it should be free.; (cont.) However, to limit over consumption, the quantity of water over the allowance should be priced. The results showed that this kind of pricing schedule would be efficient in significantly reducing demand. The models show that a price of water of $1/m3...

‣ Fracture of porous materials induced by crystallization of salt

Katzoff, Golda Y
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 44 leaves; 1860794 bytes; 1862530 bytes; application/pdf; application/pdf
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The penetration of salt into porous materials is known to have deleterious effects, often resulting in fracture. The damage process begins with a saline solution penetrating the porous network by way of capillary action. This is followed by supersaturation of the saline solution, which may result in the formation of salt crystals. In turn, these salt crystals induce pressure on the pore walls. Though the stress generated by the crystallization of salt in a single pore alone is unlikely to result in fracture, if the crystallization region is large enough, the combined effects can lead to fracture. This thesis will first provide an overview of the crystallization process and then focus on the factors leading directly to fracture. The thesis will examine various key processes proposed by researchers, identify elements that have not yet been explored, and finally propose a cohesive outline of the processes responsible for fracture.; by Golda Y. Katzoff.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2006.; Includes bibliographical references (leaf 40).

‣ A multiscale approximation algorithm for the cardinality constrained knapsack problem

Krishnan, Bharath Kumar
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 86 leaves; 2920986 bytes; 2924517 bytes; application/pdf; application/pdf
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I develop a multiscale approximation algorithm for the cardinality constrained knapsack problem. The algorithm consists of three steps: a rounding and reduction step where a hierarchical representation of the problem data ranging from coarse to fine is generated, a solution step where a coarse solution is computed, and a refinement step where the accuracy of the solution is improved by refining the problem representation. I demonstrate that the algorithm is fully polynomial with a runtime complexity that improves upon the previous best known fully polynomial approximation scheme. Through an extensive computational study, I show that the running times of the algorithm is less than or equal to that of a commercial integer programming package with little loss in solution accuracy.; by Bharath Kumar Krishnan.; Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2006.; Includes bibliographical references (leaves 83-86).

‣ Sequential investment planning for complex oil development projects

Aydın, Cevat Onur
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 90 leaves
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In this thesis, we consider sequential real investment decisions for the development of discovered oil prospects. Following a decision analysis approach, we propose a methodology to explore the upside of a dynamic drilling strategy, where there is a significant uncertainty about the reservoir complexity. We introduce the notion of information lag, whereby the decision-maker receives the information with a certain delay after each drilling is completed. In an illustrative case study, we apply our proposed methodology on a single reservoir to characterize the value of flexibility and to describe the relative impact of the information lags, in the context of an extensive drilling plan. We also provide several extensions of this case study in order to show how this methodology would be extended in a more comprehensive decision framework. Topics include choosing the optimal production capacity, valuing an initial test opportunity, and developing a field with multiple reservoirs. Our results indicate that flexible thinking may be a significant source of value to the projects. However, the incremental value might be over-rated if information lags are not appropriately included in the analysis.; by Cevat Onur Aydın.; Thesis (S.M.)--Massachusetts Institute of Technology...

‣ Optimization of outrigger structures

Lame, Ali
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 88 leaves
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Designing a high rise building has its challenges. Different structural systems have been developed to control the lateral displacement of high rise buildings. One of these systems is called the outrigger which decreases both the horizontal movement of the structure and the moment on the foundation of the structure. However the location of the outriggers has an immense influence on the efficiency of the structure. Outrigger optimization is a significant challenge. The objective of this thesis is to give a better understanding of outrigger location optimization and the efficiency of each outrigger when several outriggers are used in the structure. An optimization is also performed on a certain configuration of an outrigger to a concrete core. Finally a program has been developed that enables the user to analyze a structure with up to 10 outriggers.; by Ali Lame.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2008.; Includes bibliographical references (leaf 68).

‣ Nutrient load analysis of Lago de Yojoa, Honduras

Trate, Tia M. (Tia Marie)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 52 leaves; 9262481 bytes; 9262158 bytes; application/pdf; application/pdf
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Lake Yojoa, Honduras is an important natural resource to the people of Honduras. The lake's water quality has been a controversial subject. This thesis describes a nutrient load analysis performed to gain a better understanding of the water quality. Loads were calculated for point sources, non-point sources, and other sources. These loads were applied to a trophic model to determine the lake's trophic status. The results of this study seem to point out that much about tropical limnology is unknown. Lake Yojoa appears to be a mesotrophic lake with nitrogen as the limiting nutrient. However, further field evaluation of the limiting nutrient and nutrient loadings is recommended in order to provide information for better management of the lake.; by Tia M. Trate.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2006.; Includes bibliographical references (leaves 47-49).

‣ Conceptual design of a building with movable parts

De Antonio Crespo, Andrés
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 63 leaves
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Although we live in a Dynamic Universe filled with movement, the design methodology that has been given to Architecture is clearly static: buildings look the same all the time. As an approach to "Dynamic Architecture", the design of a building with a changing geometry is examined in an attempt to explore factors that affect the design of this type of building. The proposed building is 200 m in height and follows the shape of a "T", it has a movable structure on its top that can rotate 360 degrees. Because of the changing geometry of the building due to the rotation of the upper part, two assumptions can be made in the structural analysis: a. that the changing geometry drastically changes the dynamic behavior of the building, or b. that this changing geometry doesn't affect at all the dynamic behavior. Since the movement will be slow, the structural analysis can be quasi-static. The cantilevered structure acts as a concentrated mass on the top of the building which is an important factor to consider against seismic loads. The design of the connection of the movable structure to the building is a critical aspect so it can move but at the same time be fixed to the building. A correct assumption of the modeling of this connection is critical in the structural analysis. Due to the rotation of the upper part...

‣ An operator-customized wavelet-finite element approach for the adaptive solution of second-order partial differential equations on unstructured meshes

D'Heedene, Stefan F., 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 142 p.; 7790492 bytes; 7809006 bytes; application/pdf; application/pdf
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The Finite Element Method (FEM) is a widely popular method for the numerical solution of Partial Differential Equations (PDE), on multi-dimensional unstructured meshes. Lagrangian finite elements, which preserve C⁰ continuity with interpolating piecewise-polynomial shape functions, are a common choice for second-order PDEs. Conventional single-scale methods often have difficulty in efficiently capturing fine-scale behavior (e.g. singularities or transients), without resorting to a prohibitively large number of variables. This can be done more effectively with a multi-scale method, such as the Hierarchical Basis (HB) method. However, the HB FEM generally yields a multi-resolution stiffness matrix that is coupled across scales. We propose a powerful generalization of the Hierarchical Basis: a second-generation wavelet basis, spanning a Lagrangian finite element space of any given polynomial order.; by Stefan F. D'Heedene.; Thesis (Ph. D.)--Massachusetts Institute of Technology, Civil and Environmental Engineering, 2005.; Includes bibliographical references (p. 139-142).Unlike first-generation wavelets, second-generation wavelets can be constructed on any multi-dimensional unstructured mesh. Instead of limiting ourselves to the choice of primitive wavelets...

‣ Application of damping in high-rise buildings

O'Neill, Jeremiah C. (Jeremiah Charles)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 62 leaves; 2603669 bytes; 2606180 bytes; application/pdf; application/pdf
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The outrigger structural system has proven to be an efficient lateral stiffness system for high-rise buildings under static loadings. The purpose of this thesis is to research the incorporation of viscous dampers into the outrigger system to improve the dynamic performance. This study will be conducted on a typical high-rise structure in Boston, MA in attempt to find realistic results. This thesis will utilize two analysis models for the study: a simplified single degree of freedom model and a more sophisticated computer model constructed with the structural analysis software, SAP2000. The models will be used to assess the effect that increasing damping or changing damper locations has on the dynamic performance of the structure. Furthermore, the constructability issues of each damping configuration will be identified and discussed.; by Jeremiah C. O'Neill, Jr.; Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2006.; Includes bibliographical references (;eaf 60).

‣ Development of a wireless sensor unit for tunnel monitoring; Wireless infrastructure monitoring

Cheekiralla, Sivaram M. S. L., 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 138 p.; 4949534 bytes; 4949340 bytes; application/pdf; application/pdf
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In this thesis we describe the development of a wireless sensor module for tunnel monitoring. The tunnel in question is a part of the London Underground system. Construction of a new tunnel beneath the existing tunnel is anticipated to cause quantifiable vertical displacement. To ensure safe operation of the tunnel during the construction activity, a real-time monitoring system has been created to measure vertical displacements along the critical zone near Highbury & Islington station. A geomechanical analysis, provided by a third party, is used to establish the allowable maximum displacement. A custom wireless sensor module was developed from off-the-shelf components. This module consists of a sensor device, microcontroller, ADC and RF transmitter. The integration of these components is described in detail. Deployment details and some preliminary results are presented.; by Sivaram M.S.L. Cheekiralla.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2004.; Includes bibliographical references (p. 133-138).