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Electrical Engineering and Computer Sciences - Master's degree

Mostrando recursos 1 - 20 de 6.601

  1. A receiver-compatible noise reduction system

    Bace, Matthew M. (Matthew Mark)
    by Matthew M. Bace.

  2. The effect of coupling in automotive active suspensions

    Malek, Kamal Moussa
    by Kamal Moussa Malek.

  3. Leto : verifying application-specific fault tolerance via first-class execution models

    Boston, Brett (Brett Cyrus)
    Due to the aggressive scaling of technology sizes in modern computer processor fabrication, modern processors have become less reliable and more prone to exposing hardware errors to software. In response, researchers have recently designed a number of application-specific fault tolerance mechanisms that enable applications to either be naturally resilient to errors or include additional detection and correction steps that can bring the overall execution of an application back into an envelope for which an acceptable execution is eventually guaranteed. A major challenge to building an application that leverages these mechanisms, however, is to verify that the implementation satisfies the basic...

  4. Measuring time to interactivity for modern Web pages

    Nathan, Vikram
    Web pages continually strive for faster loading times to improve user experience. However, a good metric for "page load time" is elusive. In particular, we contend that modern web pages should be evaluated with respect to interactivity: a page should be considered loaded when the user can fully interact with all visible content. However, existing metrics fail to accurately measure interactivity. On one hand, "page load time", the most widely used metric, overestimates the time to full interactivity by requiring that all content on a page has been both fetched and evaluated, including content below-the-fold that is not immediately visible...

  5. The value of data

    Jones, Dalton James
    Data and information are integral to the modern economic system. Advances in technology have allowed companies to both collect and utilize vast amounts of data. At times this data can be very private and collected surreptitiously. Smartphones and other devices that keep us in constant contact with the internet provide companies like Google and Facebook with a wealth of information to sell. Despite all this, there currently does not exist a systematic way to value data. In the absence of such valuations, gross economic inefficiencies are inevitable. In this thesis, we seek to model ways in which data can be...

  6. Hybrid power-system architecture for micro-grid

    Ibrahim, Shibal
    Load-independent, fixed-speed operation of prime-movers, such as gas turbines and diesel engines, leads to degraded efficiency at part-loaded conditions. This thesis looks at a hybrid power-system architecture that can boost fuel economy through coordinated variable-speed operation of both prime-movers and drive loads. The propulsion plant of an electric ship serves as an example of a micro-grid with a focus on efficiency and dynamic performance. The proposed power distribution system employs doubly-fed machines for generation and for variable speed loads, and can be used where variable-speed operation improves prime-mover efficiency while minimizing required power electronics ratings. The hybrid power-system architecture achieves...

  7. Robust synthetic control

    Shen, Dennis, S.M. Massachusetts Institute of Technology
    In this thesis, we present a robust generalization of the synthetic control method. A distinguishing feature of our algorithm is that of de-noising the data matrix via singular value thresholding, which renders our approach robust in multiple facets: it automatically identifies a good subset of donors, functions without extraneous covariates (vital to existing methods), and overcomes missing data (never been addressed in prior works). To our knowledge, we provide the first theoretical finite sample analysis for a broader class of models than previously considered in literature. Additionally, we relate the inference quality of our estimator to the amount of training...

  8. Localizing external contact using proprioceptive sensors : the contact particle filter

    Manuelli, Lucas
    In order for robots to interact safely and intelligently with their environment they must be able to reliably estimate and localize external contacts. This paper introduces the CPF, the Contact Particle Filter, which is a general algorithm for detecting and localizing external contacts on rigid body robots without the need for external sensing. The CPF finds external contact points that best explain the observed external joint torque, and returns sensible estimates even when the external torque measurement is corrupted with noise. We demonstrate the capability of the CPF in multiple scenarios. We show how it can track multiple external contacts...

  9. High speed swept source optical coherence tomography handheld instrument at 1310nm for point-of-care imaging

    Yiu, Patrick (Patrick Wai-Kit)
    Optical coherence tomography (OCT) is a novel biomedical imaging technique that functions as a type of "optical biopsy" by using low coherence interferometry to non-invasively generate high resolution cross-sectional images of tissue in real time. OCT has become a standard diagnostic tool in ophthalmology and investigators have demonstrated OCT in a variety of biomedical applications including cardiology, gastroenterology, dermatology, and urology. Recent research advances in swept source lasers have enabled swept source OCT (SS-OCT) to achieve imaging speeds 5-50x faster than commercially available spectral domain OCT (SD-OCT) systems. This thesis describes the design of a handheld SS-OCT instrument for portable-real-time...

  10. A unified compiler backend for distributed, cooperative heterogeneous execution

    Ray, Jessica Morgan
    In many of today's applications, achieving high-performance is critical. Numerous architectures, such as shared memory systems, distributed memory systems, and heterogeneous systems, are all used in high-performance computing. However, all of these have different optimizations and programming models. Additionally, performance is not always portable across architectures-one optimization that provides significant improvement in one system may have little to no effect in another system. Writing high-performance code is a notoriously difficult task that requires significant trial-and-error. Writing high-performance code for multiple architectures is even harder, particularly when these architectural components are all together in a single heterogeneous system and the programmer...

  11. Typesafety for explicitly-coded probabilistic inference procedures

    Atkinson, Eric Hamilton
    Researchers have recently proposed several systems that ease the process of developing Bayesian probabilistic inference algorithms. These include systems for automatic inference algorithm synthesis as well as stronger abstractions for manual algorithm development. However, existing systems whose performance relies on the developer manually constructing a part of the inference algorithm have limited support for reasoning about the correctness of the resulting algorithm. In this thesis, I present Shuffle, a programming language for developing manual inference algorithms that enforces 1) the basic rules of probability theory and 2) statistical dependencies of the algorithm's corresponding probabilistic model. We have used Shuffle to...

  12. Towards optimal capacity-achieving transceivers with photonic integrated circuits

    Prabhu, Mihika
    Optical communication systems have many advantages over communication systems that operate in the radio-frequency range, including decreased size, weight, and power consumption and increased bandwidth. As a result, optical communication systems are emerging as the ideal choice in many resource-constrained links such as those deployed on spacecraft. This thesis presents progress on development of a programmable nanophotonic processor (PNP) for implementing a high-fidelity reconfigurable optical transceiver at the telecommunications wavelength. By encoding information in multiple spatial modes and detecting jointly over the modes using a unitary transform prior to detection, one can in principle attain Holevo-limited channel capacity in the...

  13. Digital scaling of binary images

    Ulichney, Robert
    by Robert A. Ulichney.

  14. Observing the observers : a new experimental paradigm for the study of seeing and drawing

    Ozgirin, Ege
    One way to study how people design is to understand how others observe them designing. I take a step towards this understanding by examining how people segment visual design events temporally, in other words, how they divide these events into smaller pieces. I developed a methodology to comparatively study how multiple observers segment design events. In order to test my methodology, I conducted an experiment. In this experiment, I compared different attributes of a design event to see if some attributes communicate more meaning than others. From the results of the experiment, I observed that the segmentation of the design...

  15. Ludus ex machina : toward computational play

    Penman, Scott (Scott David)
    The day is not far off when autonomous, artificially intelligent computational subjects will be employed in creative industries such as architecture and design. Artificial intelligence is rapidly becoming ubiquitous, and it has absorbed many capabilities once thought beyond its reach. As such, it is critical that we reflect on AI's ability to design, and on whether we are affording our creative computational counterparts the full range of tools and freedoms utilized by designers. Design is often tasked with pushing the envelope in the quest for novel meaning and experience. Designers can't always rely upon existing models to judge their work....

  16. Diffractive electron mirror for use in quantum electron microscopy

    Abedzadeh, Navid
    Periodic atomic structures in thin crystals and artificially fabricated periodic structures in transmission gratings have long been used to coherently split electrons by means of electron diffraction for applications such as interferometry, holography and imaging. Due to their reliance on transmission through matter, however, these methods are prone to electron scattering and absorption and are therefore lossy to some extent. This loss becomes a major issue for quantum electron microscopy (QEM), an interaction-free measurement scheme with electrons as probe particles. QEM relies on single electrons completing many round trips inside an electron resonant cavity, splitting and re-coupling during each round...

  17. Unfield sparse formats for tensor algebra compilers

    Chou, Stephen, S.M. Massachusetts Institute of Technology
    Tensor algebra is a powerful tool for computing on multidimensional data and has applications in many fields. Practical applications often deal with tensors that are sparse, and there exists a wide variety of formats for storing such tensors, each suited to specific types of applications and data. Examples of sparse tensor storage formats include COO, CSR, CSC, DCSR, BCSR, CSF, CSB, ELL, DIA, and hash maps. In this thesis, we propose a levelized hierarchical abstraction that represents these seemingly disparate formats and countless others, and that hides the details of each format behind a common interface. We show that this...

  18. Super-resolution localization and readout of individual solid-state qubits

    Bersin, Eric (Eric A.)
    A central goal in quantum information science is to establish entanglement across multiple quantum memories in a manner that allows individual control and readout of each constituent qubit. In the area of solid state quantum optics, a leading system is the negatively charged nitrogen vacancy center in diamond, which allows access to a spin center that can be entangled to multiple nuclear spins. Scaling these systems will require the entanglement of multiple NV centers, together with their nuclear spins, in a manner that allows for individual control and readout. Here we demonstrate a technique that allows us to prepare and...

  19. Reconfigurable neural probe for chronic recording

    Meng, Boying
    To facilitate the usage of neural prosthesis, a sustainable recording method of cleaner neural signals is desired. While invasive neural electrodes can record neural activities with less noise than non-invasive methods and provide the ideal spatial-temporal resolution of the recorded signal, one major challenge of this invasive method is the potential tissue responses. The scar tissue that forms around the penetrating tip of the electrode may significantly degrade the signal quality in time, which causes the reading to be unreliable in the long-term. Solving this problem is key to enabling chronic usage of neural prosthetic systems. To tackle this challenge,...

  20. Policy regularized model predictive control framework for robust legged locomotion

    Bledt, Gerardo
    A novel Policy Regularized Model Predictive Control (PR-MPC) framework is developed to allow general robust legged locomotion with the MIT Cheetah quadruped robot. The full system is approximated by a simple control model that retains the key nonlinearities characteristic to legged contact dynamics while reducing the complexity of the continuous dynamics. Nominal footstep locations and feedforward forces for controlling the robot's center of mass are designed from simple physics-based heuristics for steady state legged movement. By regularizing the predictive optimization with these policies, we can exploit the known dynamics of the system to bias the controller towards the steady state...

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