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Electrical Engineering and Computer Sciences - Master's degree

Mostrando recursos 1 - 20 de 6.104

  1. Interactive design process based on augmented intelligence : a framework and toolkit for designers to interact and collaborate with AI algorithms

    Cheng, Chin-Yi
    Designers can use artificial intelligence, such as Genetic Algorithms, to deal with the design problems which seem impossible to be quickly resolved by the human mind. However, none of the current Al algorithms interact with the designers while executing the assigned tasks. Therefore, when the designers use Al to generate design solutions, they can only pick from the results and often feel that their creativity is deprived. Also, it is often the case that designers are not satisfied with the generated results because the algorithms cannot optimize goals which have not been represented as numerical values, such as aesthetic. Moreover,...

  2. Analysis of Mo sidewall ohmic contacts to InGaAs fins

    Choi, Dongsung
    As transistor size is scaled down, the performance is degraded and many problems, so called shortchannel effects, arise. To address this problem, a vertical transistor structure such as vertical nanowire is suggested. In a vertical nanowire field-effect-transistor, the Ohmic contact at the top of the nanowire not only covers the top surface, but also wraps around the sidewall. Because the sidewall is considered to be different from the top surface, it is necessary to study the sidewall Ohmic contact properties such as the contact resistivity. In this thesis, to explore sidewall contact resistivity, a theoretical model for sidewall contacts is...

  3. Verifying an I/O-concurrent file system

    Chajed, Tej
    Systems software is a good target for verification due to its prevalent usage and its complexity, which can lead to tricky bugs that are hard to test for. One source of complexity in systems software is concurrency, but thus far verification techniques have struggled to enable large-scale verification of concurrent systems. This thesis contributes a verified file system, CIO-FSCQ, with I/O concurrency: if a file system call experiences a miss in the buffer cache and starts a disk I/O, the file system overlaps the I/O with the execution of another file system call. CIO-FSCQ re-uses the implementation, specifications, and proofs...

  4. Photonic crystal cavity with self-similar structure and single-photon Kerr nonlinearities

    Choi, Hyeongrak
    We propose a design of photonic crystal cavity with self-similar electromagnetic boundary conditions, that achieve ultrasmall mode volume (Vff). The electric energy density of a cavity mode can be maximized in the air or dielectric region, depending on the choice of boundary conditions. We illustrate the design concept with a silicon-air ID photon crystal cavity that reaches an ultrasmall mode volume of Vff ~ 7.01 x 10- 5 [lambda]3 at [lambda] ~ 1550 nm. We show that the extreme light concentration in our design can enable ultra-strong Kerr nonlinearities, even at the single photon level. These features open new directions...

  5. Beating the world's best at Super Smash Bros. with deep reinforcement learning

    Firoiu, Vlad
    There has been a recent explosion in the capabilities of game-playing artificial intelligence. Many classes of RL tasks, from Atari games to motor control to board games, are now solvable by fairly generic algorithms, based on deep learning, that learn to play from experience with often minimal knowledge of the specific domain of interest. In this work, we will investigate the performance of these methods on Super Smash Bros. Melee (SSBM), a popular multiplayer fighting game. The SSBM environment has complex dynamics and partial observability, making it challenging for man and machine alike. The multiplayer aspect poses an additional challenge,...

  6. Design and fabrication of an open-architecture selective laser melting system

    Baker, Stuart Polak
    Additive manufacturing (AM) is a rapidly advancing manufacturing paradigm that involves selective placement of material, layer-by-layer, as determined by a three-dimensional digital model. AM allows for freeform geometries and optimized structures that are impractical or impossible to create with traditional manufacturing practices. Among several mainstream AM methods, powder bed fusion is compatible with both plastics and metals, and thereby allows construction of a wide spectrum of end-use parts. A significant challenge in exploring this process from a research perspective is the predominance of commercial systems which are costly and offer limited flexibility to the user. To address this challenging lack...

  7. Integrated perception and control at high speed

    Florence, Peter R. (Peter Raymond)
    We present a method for robust high-speed quadrotor flight through unknown cluttered environments using integrated perception and control. Motivated by experiments in which the difficulty of accurate state estimation was a primary limitation on speed, our method forgoes maintaining a map in favor of using only instantaneous depth information in the local frame. This provides robustness in the presence of significant state estimate uncertainty. We compare the method against a benchmark approach using a simulated quadrotor race through a forest at high speeds in the presence of increasing state estimate noise. We then present hardware validation experiments in both indoor...

  8. RNAi-based logic circuitry coupled to Cas9-mediated transcriptional control in human cells and applications to stem cell technology

    Palacios, Sebastian Ricardo
    This work demonstrates fundamental advancements towards the construction of an RNAi-based molecular computing core genetically encoded in the genome of human induced pluripotent stem cells (hiPSCs). This architecture can be theoretically programmed to precisely control stem cell differentiation. First, we use computational biology to analyze differential miRNA expression during human stem cell differentiation and guide biological design. We then design, build, and test proof-of-concept RNAi-based circuits in living human cells and couple them to Cas9-mediated transcriptional control. Finally, we demonstrate stable integration of an RNAi-based sensor in chromosome 19 (AAVS1 locus) of hiPSCs using landing pad technology followed by successful...

  9. Creating interactive data-driven web applications by authoring HTML

    Verou, Lea
    Many people can author static web pages with HTML and CSS but find it hard or impossible to program persistent, interactive web applications. We show that for a broad class of CRUD (Create, Read, Update, Delete) applications, this gap can be bridged. Mayo extends the declarative syntax of HTML to describe Web applications that manage, store and transform data. Using Mayo, authors with basic HTML knowledge define complex data schemes implicitly as they design their HTML layout. They need only add a few attributes and expressions to their HTML elements to transform their static design into a persistent, data-driven web...

  10. Scalable creation of spin-photon interfaces for solid-state quantum information processing

    Wan, Noel H. (Noel Heng Loon)
    The negatively charged nitrogen vacancy (NV) defect center in diamond is a promising solid-state qubit due to its exceptional spin and optical properties. In this thesis, we develop high-yield, efficient spin-photon interfaces in diamond. In particular, we demonstrate a process that produces dielectic reflectors and photonic crystal nanobeam cavities directly on the surface of bulk diamond. Our results pave the way towards a scalable network of entangled quantum registers based on spin qubits in diamond.

  11. Capturing the human figure through a wall

    Hsu, Chen-Yu, S.M. Massachusetts Institute of Technology
    We present RF-Capture, a system that captures the human figure - i.e., a coarse skeleton - through a wall. RF-Capture tracks the 3D positions of a person's limbs and body parts even when the person is fully occluded from its sensor, and does so without placing any markers on the subject's body. In designing RF-Capture, we built on recent advances in wireless research, which have shown that certain radio frequency (RF) signals can traverse walls and reflect off the human body, allowing for the detection of human motion through walls. In contrast to these past systems which abstract the entire...

  12. Embedding and latent variable models using maximal correlation

    Qui, David (David Da)
    Finding low dimensional latent variable models is a useful technique in inferring unobserved affinity between unobserved co-occurrences. We explore using maximal correlation and the alternating conditional expectation algorithm to construct embeddings one dimensional at a time to maximally preserve the linear correlation in the embedding space. Each dimension is enforced to be orthogonal to all other dimensions to not encode redundant information. Intuitively, we want to map objects that frequently co-occur to be close in the embedding space. However, often there are unobserved or under-sampled pairs that skew the result. We derive simple regularization techniques to compensate for those outliers....

  13. Improved magnetic resonance chemical shift imaging at 3 Tesla using a 32-channel integrated RF-shim coil array

    Kızıldağ, Eren C
    In vivo chemical shift imaging is an imaging modality which uses the so-called chemical-shift phenomenon to quantitate brain metabolites spatially, therefore renders the study of brain metabolism and neurodegenerative diseases possible and eases diagnosis of tumors. However, the method is highly vulnerable to local main magnetic field (Bo) inhomogeneities arising from magnetic susceptibility differences which is predominantly present in air-tissue interfaces. Such magnetic field inhomogeneities result in number of imaging artifacts including chemical shift displacement of metabolites, spectral line broadening as well as complicated water and lipid suppression; which reduce spectral quality. The main goal of this work is to...

  14. Superconducting nanowire single-photon detectors on aluminum nitride photonic integrated circuits

    Zhu, Di, S.M. Massachusetts Institute of Technology
    With recent advances in integrated single-photon sources and quantum memories, onchip integration of high-performance single-photon detectors becomes increasingly important. The superconducting nanowire single-photon detector (SNSPD) is the leading single-photon counting technology for quantum information processing. Among various waveguide materials, aluminum nitride (AlN) is a promising candidate because of its exceptionally wide bandgap, and intrinsic piezoelectric and electro-optic properties. In this Master's thesis, we developed a complete fabrication process for making high-performance niobium nitride SNSPDs on AlN, and demonstrated their integration with AlN photonic waveguides. The detectors fabricated on this new substrate material have demonstrated saturated detection efficiency from visible to...

  15. Contraction maps and applications to the analysis of iterative algorithms

    Zampetakis, Emmanouil
    The increasing interest of the scientific community, and especially machine learning, on non-convex problems, has made non-convex optimization one of the most important and challenging areas of our days. Despite of this increasing interest too little is known from a theoretical point of view. The main reason for this is that the existing and well understood techniques used for the analysis of convex optimization problem are not applicable or meaningful in the non-convex case. The purpose of this thesis is to make a step in the direction of investigating a rich enough toolbox, to be able to analyze non-convex optimization....

  16. Artificial intelligence and protein engineering : information theoretical approaches to modeling enzymatic catalysis

    Weis, James W. (James Woodward)
    The importance of dynamics in enzymatic function has been extensively recognized in the literature. Despite this, the vast majority of enzyme engineering approaches are based on the energetic optimization of static molecular structures. Using computational sampling techniques, especially rare-event sampling methods like Transition Path Sampling, we can now generate large datasets of reactive and non-reactive enzyme trajectories. However, due to the high dimensionality of phase space, as well as the highly correlated nature of proteins, using these simulations to understand the drivers of reactivity, or as a starting point for enzyme engineering, is difficult. In this work, we apply information...

  17. Optimal sizing of solar and battery assets in decentralized micro-grids with demand-side management

    Mehra, Varun, S.M. Massachusetts Institute of Technology
    Solar-based community micro-grids and individual home systems have been recognized as key enablers of electricity provision to the over one billion people living without energy access to-date. Despite significant cost reductions in solar panels, these options can still be cost-prohibitive mainly due over-sizing of generation assets corresponding with a lack of ability to actively manage electricity demand. The main contribution shared is the methodology and optimization approach of least-cost combinations of generation asset sizes, in solar panels and batteries, subject to meeting reliability constraints; these results are based on a techno-economic modeling approach constructed for assessing decentralized micro-grids with demand-side...

  18. Electricity market integration of stochastic renewable resources : efficiency and risk tradeoffs

    Schneider, Ian Michael
    Electricity generation from renewable sources is growing rapidly, but the variability and uncertainty of renewable resources like wind and solar energy can increase the costs of supplying reliable electricity. Competitive markets for wholesale electricity are widely used in the United States, but the regulatory details that govern their treatment of stochastic resources can have significant effects on efficiency and risk. This research analyzes how producers respond to market mechanisms intended to improve forecasting and long-term siting decisions. This thesis characterizes producer equilibrium strategies in competitive short term energy markets by examining the bidding behavior of energy market participants when energy...

  19. Design and validation of mobile kit and machine learning algorithms for pulmonary disease screening and diagnosis

    Chamberlain, Daniel
    Pulmonary diseases are responsible for more than 15% of deaths worldwide. Much of this burden is concentrated in the developing world, where these diseases cause 19% of deaths. In much of the developing world, pulmonary diseases are under-diagnosed and misdiagnosed because the correct equipment is not available or health care is provided by workers with insufficient training. To help improve the diagnosis of pulmonary disease, we built a pulmonary diagnostic kit that consists of an electronic stethoscope, an augmented reality peak flow meter, and an electronic questionnaire. Using this kit, we collected data from patients who visited the Chest Research...

  20. Visual memory

    Kollogg, Christopher James
    by Christopher James Kellogg.

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