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Consensus and collision detectors in wireless ad hoc networks

Newport, Calvin (Calvin Charles)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 80 leaves
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In this study, we consider the fault-tolerant consensus problem in wireless ad hoc networks with crashprone nodes. Specifically, we develop lower bounds and matching upper bounds for this problem in single-hop wireless networks, where all nodes are located within broadcast range of each other. In a novel break from existing work, we introduce a highly unpredictable communication model in which each node may lose an arbitrary subset of the messages sent by its neighbors during each round. We argue that this model better matches behavior observed in empirical studies of these networks. To cope with this communication unreliability we augment nodes with receiver-side collision detectors and present a new classification of these detectors in terms of accuracy and completeness. This classification is motivated by practical realities and allows us to determine, roughly speaking, how much collision detection capability is enough to solve the consensus problem efficiently in this setting. We consider ten different combinations of completeness and accuracy properties in total, determining for each whether consensus is solvable, and, if it is, a lower bound on the number of rounds required.; (cont.) Furthermore, we distinguish anonymous and non-anonymous protocols-where "anonymous" implies that devices do not have unique identifiers-determining what effect (if any) this extra information has on the complexity of the problem. In all relevant cases...

An electromechanical valve drive incorporating a nonlinear mechanical transformer

Chang, Woo Sok, 1964-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 147 leaves
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In traditional internal combustion engines, a camshaft acts on the valve stems to open and close the valves. Valve timing is fixed relative to piston position. On the other hand, if a valve is flexibly controlled by a variable valve actuation (VVA) system, we can achieve significant improvements in fuel efficiency, engine performance, and emissions. One of the most advanced variable valve actuation systems is the VVA operated by an electromechanical actuator without a camshaft, the so-called bi-positional electromechanical valve drive (EMVD). Existing EMVDs characteristically use a spring to provide the required mechanical power for operating a valve. The use of a spring provides many benefits to the design of the system, but it also results in difficult design challenges. The large holding force against the spring at the ends of the stroke suggests the use of a normal-force electromagnetic actuator, which, from a servomechanical point of view, is considerably inferior to a shear-force actuator. Furthermore, the large holding force generates a large jerk at the beginning and the end of a stroke and makes it difficult to achieve soft valve landing. An innovative electromechanical valve drive (EMVD) design is proposed, which incorporates a nonlinear mechanical transformer and a shear-force actuator. This allows not only fast but also smooth valve motion...

New geometric techniques for linear programming and graph partitioning

Kelner, Jonathan, 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 82 leaves
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In this thesis, we advance a collection of new geometric techniques for the analysis of combinatorial algorithms. Using these techniques, we resolve several longstanding questions in the theory of linear programming, polytope theory, spectral graph theory, and graph partitioning. The thesis consists of two main parts. In the first part, which is joint work with Daniel Spielman, we present the first randomized polynomial-time simplex algorithm for linear programming, answering a question that has been open for over fifty years. Like the other known polynomial-time algorithms for linear programming, its running time depends polynomially on the number of bits used to represent its input. To do this, we begin by reducing the input linear program to a special form in which we merely need to certify boundedness of the linear program. As boundedness does not depend upon the right-hand-side vector, we run a modified version of the shadow-vertex simplex method in which we start with a random right-hand-side vector and then modify this vector during the course of the algorithm. This allows us to avoid bounding the diameter of the original polytope.; (cont.) Our analysis rests on a geometric statement of independent interest: given a polytope ... in isotropic position...

Adaptable optimization : theory and algorithms

Caramanis, Constantine (Constantine Michael), 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 200 p.
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Optimization under uncertainty is a central ingredient for analyzing and designing systems with incomplete information. This thesis addresses uncertainty in optimization, in a dynamic framework where information is revealed sequentially, and future decisions are adaptable, i.e., they depend functionally on the information revealed in the past. Such problems arise in applications where actions are repeated over a time horizon (e.g., portfolio management, or dynamic scheduling problems), or that have multiple planning stages (e.g., network design). The first part of the thesis focuses on the robust optimization approach to systems with uncertainty. Unlike the probability-driven stochastic programming approach, robust optimization is built on deterministic set-based formulations of uncertainty. This thesis seeks to place Robust Optimization within a dynamic framework. In particular, we introduce the notion of finite adaptability. Using geometric results, we characterize the benefits of adaptability, and use these theoretical results to design efficient algorithms for finding near-optimal protocols. Among the novel contributions of the work are the capacity to accommodate discrete variables, and the development of a hierarchy of adaptability.; (cont.) The second part of the thesis takes a data-driven view to uncertainty. The central questions are (a) how can we construct adaptability in multi-stage optimization problems given only data...

Exploiting biological pathways to infer temporal gene interaction models

Kemper, Corey Ann, 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 166 p.
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An important goal in genomic research is the reconstruction of the complete picture of temporal interactions among all genes, but this inference problem is not tractable because of the large number of genes, the small number of experimental observations for each gene, and the complexity of biological networks. We focus instead on the B cell receptor (BCR) signaling pathway, which narrows the inference problem and provides a clinical application, as B cell chronic lymphocytic leukemia (B-CLL) is believed to be related to BCR response. In this work, we infer population-dependent gene networks of temporal interaction within the BCR signaling pathway. We develop simple statistical models that capture the temporal behavior of differentially expressed genes and then estimate the parameters in an Expectation-Maximization framework, resulting in clusters with a biological interpretation for each subject population. Using the cluster labels to define a small number of modes of interaction and imposing sparsity constraints to effectively limit the number of genes influencing each target gene makes the ill-posed problem of network inference tractable.; (cont.) For both the clustering and the inference of the predictive models, we have statistical results that show that we successfully capture the temporal structure of and the interactions between the genes relevant to the BCR. signaling pathway. We have confirmatory results from a biological standpoint...

Wide-area egomotion from omnidirectional video and coarse 3D structure

Koch, Olivier (Olivier A.)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 110 p.
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This thesis describes a method for real-time vision-based localization in human-made environments. Given a coarse model of the structure (walls, floors, ceilings, doors and windows) and a video sequence, the system computes the camera pose (translation and rotation) in model coordinates with an accuracy of a few centimeters in translation and a few degrees in rotation. The system has several novel aspects: it performs 6-DOF localization; it handles visually cluttered and dynamic environments; it scales well over regions extending through several buildings; and it runs over several hours without losing lock. We demonstrate that the localization problem can be split into two distinct problems: an initialization phase and a maintenance phase. In the initialization phase, the system determines the camera pose with no other information than a search region provided by the user (building, floor, area, room). This step is computationally intensive and is run only once, at startup. We present a probabilistic method to address the initialization problem using a RANSAC framework. In the maintenance phase, the system keeps track of the camera pose from frame to frame without any user interaction.; (cont.) This phase is computationally light-weight to allow a high processing frame rate and is coupled with a feedback loop that helps reacquire "lock" when lock has been lost. We demonstrate a simple...

Apparent ridges for line drawing

Judd, Tilke (Tilke M.)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 72 p.
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Non-photorealistic line drawing depicts 3D shapes through the rendering of feature lines. A number of characterizations of relevant lines have been proposed but none of these definitions alone seem to capture all visually-relevant lines. We introduce a new definition of feature lines based on two perceptual observations. First, human perception is sensitive to the variation of shading, and since shape perception is little affected by lighting and reflectance modification, we should focus on normal variation. Second, view-dependent lines better convey the shape of smooth surfaces better than view-independent lines. From this we define view-dependent curvature as the variation of the surface normal with respect to a viewing screen plane, and apparent ridges as the locus points of the maximum of the view-dependent curvature. We derive the equation for apparent ridges and present a new algorithm to render line drawings of 3D meshes. We show that our apparent ridges encompass or enhance aspects of several other feature lines.; by Tilke Judd.; Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.; Includes bibliographical references (p. 69-72).

The local geometry of multiattribute tradeoff preferences

McGeachie, Michael J
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 129 p.
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Existing preference reasoning systems have been successful in simple domains. Broader success requires more natural and more expressive preference representations. This thesis develops a representation of logical preferences that combines numerical tradeoff ratios between partial outcome descriptions with qualitative preference information. We argue our system is unique among preference reasoning systems; previous work has focused on qualitative or quantitative preferences, tradeoffs, exceptions and generalizations, or utility independence, but none have combined all of these expressions under a unified methodology. We present new techniques for representing and giving meaning to quantitative tradeoff statements between different outcomes. The tradeoffs we consider can be multi-attribute tradeoffs relating more than one attribute at a time, they can refer to discrete or continuous domains, be conditional or unconditional, and quantified or qualitative. We present related methods of representing judgments of attribute importance. We then build upon a methodology for representing arbitrary qualitative ceteris paribus preference, or preferences "other things being equal," as presented in [MD04].; (cont.) Tradeoff preferences in our representation are interpreted as constraints on the partial derivatives of the utility function. For example...

Verification of d-wave pairing symmetry by microwave intermodulation distortion measurements in yttrium barium copper oxide

Park, Sang-Hoon, Ph. D. Massachusetts Institute of Technology
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 119 p.
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We report measurements of the temperature and power dependence of the microwave frequency intermodulation distortion (IMD) in high quality pulsed laser deposition (PLD) Yttrium Barium Copper Oxide (YBCO) on LaAlO3 substrate. A low-temperature (T < 30 K) increase in IMD is the observation of an upturn of the nonlinear coefficient of the quadratic field dependence of the penetration depth. This IMD upturn is limited by the nonlinear Meissner effect that has been predicted for d-wave high-T, superconductors. Various amounts of IMD increase are observed for different films with impurity (Ni, Zn and Ca) doping and other defects. The demonstration of the IMD upturn and the nonlinear Meissner effect were possible because the IMD measurement is an extremely sensitive method to detect the penetration depth change at even less than 0.01 nm. IMDs from various samples tend to merge at a single universal value at 0 K regardless of disorder, defects, and impurities due to the node singularity at 0 K. There is a similar converging trend in IMD towards the transition temperature T, due to the quasiparticle thermal excitation and depletion of superelectrons. It is most likely that IMD has both intrinsic and extrinsic contributions.; (cont.) The 1/T2 divergence at low T of the IMD was theoretically predicted and confirmed with high quality PLD YBCO on LaA103 substrate from below 30 K. We found that Ni-doped YBCO gave an IMD increase comparable to high quality PLD YBCO. This finding agrees with the evidence that Ni (magnetic impurity) does not destroy superconductivity and preserves d-wave symmetry as shown in scanning tunneling microscope experiments. The off-the-resonance excitation experiment indicates that the response time scale of nonlinearity in IMD generation is not affected by the magnitude of two-tone separation [delta]f = f2 - fl in YBCO on LaA103 substrate. But...

Advances in cryptographic voting systems

Adida, Benjamin (Benjamin Michael), 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 254 p.
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Democracy depends on the proper administration of popular elections. Voters should receive assurance that their intent was correctly captured and that all eligible votes were correctly tallied. The election system as a whole should ensure that voter coercion is unlikely, even when voters are willing to be influenced. These conflicting requirements present a significant challenge: how can voters receive enough assurance to trust the election result, but not so much that they can prove to a potential coercer how they voted? This dissertation explores cryptographic techniques for implementing verifiable, secret-ballot elections. We present the power of cryptographic voting, in particular its ability to successfully achieve both verifiability and ballot secrecy, a combination that cannot be achieved by other means. We review a large portion of the literature on cryptographic voting. We propose three novel technical ideas: 1. a simple and inexpensive paper-base cryptographic voting system with some interesting advantages over existing techniques, 2. a theoretical model of incoercibility for human voters with their inherent limited computational ability, and a new ballot casting system that fits the new definition, and 3. a new theoretical construct for shuffling encrypted votes in full view of public observers.; by Ben Adida.; Thesis (Ph. D.)--Massachusetts Institute of Technology...

A thermally efficient micro-reactor for thermophotovoltaic power generation; Thermally efficient MR for TPV power generation

Nielsen, Ole Mattis, 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 150 p.
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Hydrocarbon fuels exhibit very high energy densities, and micro-generators converting the stored chemical energy into electrical power are interesting alternatives to batteries in certain applications. The increasing demands in power and total energy delivered to portable consumer electronics such as laptops, and to military equipment that most soldiers carry with them today, open up opportunities for the miniaturization of different energy conversion technologies. A thermally efficient MEMS (micro electro mechanical systems) suspended micro-reactor (SpRE) for thermophotovoltaic (TPV) power generation has been designed and fabricated. In TPV systems, photocells convert radiation from a combustion-heated emitter, into electrical power. TPV is an indirect conversion scheme that goes through the thermal domain and therefore does not exhibit very high efficiencies. However. because of its simple structure and because the combustor and photocell fabrication processes do not need to be integrated, the system is simpler to micro-fabricate than other generator types, such as thermoelectric systems and fuel cells. It is also a mechanically passive device that is virtually noiseless and less subject to wear than engines and turbines.; (cont.) The SptRE serves as a catalytic combustor-emitter...

Electromagnetically Induced Transparency and electron spin dynamics using superconducting quantum circuits; EIT and electron spin dynamics using SQC

Murali, Kota, 1980-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 156 p.
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This thesis is an exploration on superconducting devices, quantum optics, and magnetic resonance. Superconductive quantum circuits (SQC) comprising mesoscopic Josephson junctions can exhibit quantum coherence amongst their macroscopically large degrees of freedom. They feature quantized flux and/or charge states depending on their fabrication parameters, and the resultant quantized energy levels are analogous to the quantized internal levels of an atom. This thesis builds on the SQC-atom analogy to quantum optical effect associated with atoms, known as Electromagnetically Induced Transparency (EIT). An EIT (denoted as S-EIT) based technique has been proposed to demonstrate microwave transparency using a superconductive quantum circuit exhibiting two metastable states (e.g., a qubit) and a third, shorter-lived state (e.g., the readout state). This technique is shown to be a sensitive probe of decoherence, besides leading to the prospects of observing other interesting quantum optical effects like AC-stark effect in SQCs.; (cont.) The second part of this thesis concerns a novel technique for sensitive detection of magnetic resonance using SQC-based resonance circuits. Superconducting quantum circuits are also known to sensitive detectors of magnetic fields. In particular...

Distributed detection and coding in information networks

Ho, Shan-Yuan
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 136 p.
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This thesis investigates the distributed information and detection of a binary source through a parallel system of relays. Each relay observes the source output through a noisy channel, and the channel outputs are independent conditional on the source input. The relays forward limited information through a noiseless link to the final destination which makes an optimal decision. The essence of the problem lies in the loss of information at the relays. To solve this problem, the characteristics of the error curve are established and developed as a tool to build a fundamental framework for analysis. For understanding, the simplest non-trivial case of two relays, each forwarding only a single binary digit to the final destination is first studied. If the binary output constraint is removed and the output alphabet size for one relay is M, then no more than M + 1 alphabet symbols are required from the other relay for optimal operation. For arbitrary channels, a number of insights are developed about the structure of the optimal strategies for the relay and final destination. These lead to a characterization of the optimal solution. Furthermore, the complete solution to the Additive Gaussian Noise channel is also provided.; by Shan-Yuan Ho.; Thesis (Ph. D.)--Massachusetts Institute of Technology...

Statistical dependence estimation for object interaction and matching

Tieu, Kinh H. (Kinh Han), 1976-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 103 p.
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This dissertation shows how statistical dependence estimation underlies two key problems in visual surveillance and wide-area tracking. The first problem is to detect and describe interactions between moving objects. The goal is to measure the influence objects exert on one another. The second problem is to match objects between non-overlapping cameras. There, the goal is to pair the departures in one camera with the arrivals in a different camera so that the resulting distribution of relationships best models the data. Both problems have become important for scaling up surveillance systems to larger areas and expanding the monitoring to more interesting behaviors. We show how statistical dependence estimation generalizes previous work and may have applications in other areas. The two problems represent different applications of our thesis that statistical dependence estimation underlies the learning of the structure of probabilistic models. First, we analyze the relationship between Bayesian, information-theoretic, and classical statistical methods for statistical dependence estimation. Then, we apply these ideas to formulate object interaction in terms of dependency structure model selection.; (cont.) We describe experiments on simulated and real interaction data to validate our approach. Second...

Long-range video motion estimation using point trajectories

Sand, Peter (Peter M.), 1977-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 104 leaves
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This thesis describes a new approach to video motion estimation, in which motion is represented using a set of particles. Each particle is an image point sample with a long-duration trajectory and other properties. To optimize these particles, we measure point-based matching along the particle trajectories and distortion between the particles. The resulting motion representation is useful for a variety of applications and differs from optical flow, feature tracking, and parametric or layer-based models. We demonstrate the algorithm on challenging real-world videos that include complex scene geometry, multiple types of occlusion, regions with low texture, and non-rigid deformation.; by Peter Sand.; Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.; Includes bibliographical references (leaves 97-104).

A fully microfabricated two-dimensional electrospray array with applications to space propulsion; Fully microfabricated 2D electrospray array with applications to space propulsion

Gassend, Blaise L. P. (Blaise Laurent Patrick), 1978-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 269 p.
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This thesis presents the design, fabrication and testing of a fully-integrated planar electrospray thruster array, which could lead to more efficient and precise thrusters for space propulsion applications. The same techniques could be used for making arrays to increase throughput in many other electrospray applications. Electrospray thrusters work by electrostatically extracting and accelerating ions or charged droplets from a liquid surface to produce thrust. Emission occurs from sharp emitter tips, which enhance the electric field and constrain the emission location. The electrospray process limits the thrust from a single tip, so that achieving millinewton thrust levels requires an array with tens of thousands of emitters. Silicon batch microfabrication has been used, as it is well suited for making large arrays of emitters. The thruster is made using Deep Reactive Ion Etching (DRIE) and wafer bonding techniques, in a six mask process, and comprises two components. The emitter die with up to 502 emitters in a 113 mm2 area, is formed using DRIE and SF6 etching, and is plasma treated to transport liquid to the tips in a porous black-silicon surface layer. The extractor die incorporates the extractor electrode, a Pyrex layer for insulation...

CAPRI : a common architecture for distributed probabilistic Internet fault diagnosis; Common architecture for distributed probabilistic Internet fault diagnosis

Lee, George J. (George Janbing), 1979-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 222 p.
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This thesis presents a new approach to root cause localization and fault diagnosis in the Internet based on a Common Architecture for Probabilistic Reasoning in the Internet (CAPRI) in which distributed, heterogeneous diagnostic agents efficiently conduct diagnostic tests and communicate observations, beliefs, and knowledge to probabilistically infer the cause of network failures. Unlike previous systems that can only diagnose a limited set of network component failures using a limited set of diagnostic tests, CAPRI provides a common, extensible architecture for distributed diagnosis that allows experts to improve the system by adding new diagnostic tests and new dependency knowledge. To support distributed diagnosis using new tests and knowledge, CAPRI must overcome several challenges including the extensible representation and communication of diagnostic information, the description of diagnostic agent capabilities, and efficient distributed inference. Furthermore, the architecture must scale to support diagnosis of a large number of failures using many diagnostic agents.; (cont.) To address these challenges, this thesis presents a probabilistic approach to diagnosis based on an extensible, distributed component ontology to support the definition of new classes of components and diagnostic tests; a service description language for describing new diagnostic capabilities in terms of their inputs and outputs; and a message processing procedure for dynamically incorporating new information from other agents...

Cutting plane algorithms for variational inference in graphical models

Sontag, David Alexander
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 66 leaves
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In this thesis, we give a new class of outer bounds on the marginal polytope, and propose a cutting-plane algorithm for efficiently optimizing over these constraints. When combined with a concave upper bound on the entropy, this gives a new variational inference algorithm for probabilistic inference in discrete Markov Random Fields (MRFs). Valid constraints are derived for the marginal polytope through a series of projections onto the cut polytope. Projecting onto a larger model gives an efficient separation algorithm for a large class of valid inequalities arising from each of the original projections. As a result, we obtain tighter upper bounds on the logpartition function than possible with previous variational inference algorithms. We also show empirically that our approximations of the marginals are significantly more accurate. This algorithm can also be applied to the problem of finding the Maximum a Posteriori assignment in a MRF, which corresponds to a linear program over the marginal polytope. One of the main contributions of the thesis is to bring together two seemingly different fields, polyhedral combinatorics and probabilistic inference, showing how certain results in either field can carry over to the other.; by David Alexander Sontag.; Thesis (S.M.)--Massachusetts Institute of Technology...

An asynchronous,low-power architecture for interleaved neural stimulation, using envelope and phase information

Sit, Ji-Jon, 1975-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 124 p.
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This thesis describes a low-power cochlear-implant processor chip and a charge-balanced stimulation chip that together form a complete processing-and-stimulation cochlear-implant system. The processor chip uses a novel Asynchronous Interleaved Stimulation (AIS) algorithm that preserves phase and amplitude cues in its spectral input while simultaneously minimizing electrode interactions and lowering average stimulation power per electrode. The stimulator chip obviates the need for large D.C. blocking capacitors in neural implants to achieve highly precise charge-balanced stimulation, thus lowering the size and cost of the implant. Thus, this thesis suggests that significant performance, power and cost improvements in the current generation of cochlear implants may be simultaneously possible. The 16-channel ~90 square mm AIS processor chip was built in a 1.5[mu]m VLSI process and consumed 107[mu]W of power over and above that of its analog spectral processing front end, which consumed 250gtW and which has been previously described. The AIS processor was found to faithfully mimic MATLAB implementations of the AIS algorithm. Two perceptual tests of the AIS algorithm with normal-hearing listeners verified that AIS signal reconstructions enabled better melody and speech recognition in noise than traditional envelope-only vocoder simulations of cochlear-implant processing. The average firing rate of the AIS processor was found to be significantly lower than in traditional synchronous stimulators...

An energy efficient CMOS interface to carbon nanotube sensor arrays; energy efficient complementary metal oxide semiconductors interface to CNT sensor arrays

Cho, Taeg Sang
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 98 p.
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A carbon nanotube is considered as a candidate for a next-generation chemical sensor. CNT sensors are attractive as they allow room-temperature sensing of chemicals. From the system perspective, this signifies that the sensor system does not require any micro hotplates, which are one of the major sources of power dissipation in other types of sensor systems. Nevertheless, a poor control of the CNT resistance poses a constraint on the attainable energy efficiency of the sensor platform. An investigation on the CNT sensors shows that the dynamic range of the interface should be 17 bits, while the resolution at each base resistance should be 7 bits. The proposed CMOS interface extends upon the previously published work to optimize the energy performance through both the architecture and circuit level innovations. The 17-bit dynamic range is attained by distributing the requirement into a 10-bit Analog-to-Digital Converter (ADC) and a 8-bit Digital-to-Analog Converter (DAC). An extra 1-bit leaves room for any unaccounted subblock performance error. Several system-level all-digital calibration schemes are proposed to account for DAC nonlinearity, ADC offset voltage, and a large variation in CNT base resistance. Circuit level techniques are employed to decrease the leakage current in the sensitive frontend node...