Browsing MIT Open Access Articles by Title
Now showing items 780-799 of 55836
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Active negative-index metamaterial powered by an electron beam
(American Physical Society, 2012-08)An active negative index metamaterial that derives its gain from an electron beam is introduced. The metamaterial consists of a stack of equidistant parallel metal plates perforated by a periodic array of holes shaped as ... -
Active noise cancellation in a suspended interferometer
(American Institute of Physics (AIP), 2012-02)We demonstrate feed-forward vibration isolation on a suspended Fabry-Perot interferometer using Wiener filtering and a variant of the common least mean square adaptive filter algorithm. We compare the experimental results ... -
Active Nonlinear Acoustic Sensing of an Object with Sum or Difference Frequency Fields
(MDPI AG, 2017-09)A number of nonlinear acoustic sensing methods exist or are being developed for diverse areas ranging from oceanic sensing of ecosystems, gas bubbles, and submerged objects to medical sensing of the human body. Our approach ... -
Active Particles with Soft and Curved Walls: Equation of State, Ratchets, and Instabilities
(American Physical Society, 2016-08)We study, from first principles, the pressure exerted by an active fluid of spherical particles on general boundaries in two dimensions. We show that, despite the nonuniform pressure along curved walls, an equation of state ... -
Active perception in adversarial scenarios using maximum entropy deep reinforcement learning
(IEEE, 2019-09)© 2019 IEEE. We pose an active perception problem where an autonomous agent actively interacts with a second agent with potentially adversarial behaviors. Given the uncertainty in the intent of the other agent, the objective ... -
Active perception in adversarial scenarios using maximum entropy deep reinforcement learning
(IEEE, 2019-09)© 2019 IEEE. We pose an active perception problem where an autonomous agent actively interacts with a second agent with potentially adversarial behaviors. Given the uncertainty in the intent of the other agent, the objective ... -
Active planning for underwater inspection and the benefit of adaptivity
(2012-11)We discuss the problem of inspecting an underwater structure, such as a submerged ship hull, with an autonomous underwater vehicle (AUV). Unlike a large body of prior work, we focus on planning the views of the AUV to ... -
Active Polarimetric Measurements for Identification and Characterization of Space Debris
(Institute of Electrical and Electronics Engineers (IEEE), 2017)© 1965-2011 IEEE. A bench-top polarimeter (λ = 1064 nm) is used to measure the polarimetric bidirectional reflectance distribution function of several common spacecraft materials in both bistatic and monostatic geometries. ... -
Active Printed Materials for Complex Self-Evolving Deformations
(Nature Publishing Group, 2014-12)We propose a new design of complex self-evolving structures that vary over time due to environmental interaction. In conventional 3D printing systems, materials are meant to be stable rather than active and fabricated ... -
Active Radiative Thermal Switching with Graphene Plasmon Resonators
(American Chemical Society (ACS), 2018-03)We theoretically demonstrate a near-field radiative thermal switch based on thermally excited surface plasmons in graphene resonators. The high tunability of graphene enables substantial modulation of near-field radiative ... -
Active real-time imaging system employed with a CW 460-GHz gyrotron and a pyroelectric array camera
(Institute of Electrical and Electronics Engineers, 2009-11)We report experimental testing of an active real-time imaging system useful for many practical applications, such as fast security check, food safety inspection, etc. The system consists of a 460-GHz gyrotron capable of ... -
Active regeneration unites high- and low-temperature features in cooperative self-assembly
(American Physical Society, 2018-08)Cytoskeletal filaments are capable of self-assembly in the absence of externally supplied chemical energy, but the rapid turnover rates essential for their biological function require a constant flux of adenosine triphosphate ... -
Active Reward Learning for Co-Robotic Vision Based Exploration in Bandwidth Limited Environments
(IEEE, 2020)© 2020 IEEE. We present a novel POMDP problem formulation for a robot that must autonomously decide where to go to collect new and scientifically relevant images given a limited ability to communicate with its human operator. ... -
Active Reward Learning for Co-Robotic Vision Based Exploration in Bandwidth Limited Environments
(IEEE, 2020-05)© 2020 IEEE. We present a novel POMDP problem formulation for a robot that must autonomously decide where to go to collect new and scientifically relevant images given a limited ability to communicate with its human operator. ... -
An Active Ripple Filtering Technique for Improving Common-Mode Inductor Performance
(Institute of Electrical and Electronics Engineers (IEEE), 2004-06)Active ripple filtering is the replacement of large passive components in power filter circuits with smaller passive components and active control circuitry. This letter focuses on common-mode filters, where a large ... -
Active Sampling-Based Binary Verification of Dynamical Systems
(American Institute of Aeronautics and Astronautics, 2018-01-07)© 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. Nonlinear, adaptive, or otherwise complex control techniques are increasingly relied upon to ensure the safety of systems operating ... -
Active scaffolds for on-demand drug and cell delivery
(National Academy of Sciences (U.S.), 2011-01)Porous biomaterials have been widely used as scaffolds in tissue engineering and cell-based therapies. The release of biological agents from conventional porous scaffolds is typically governed by molecular diffusion, ... -
Active Site Threonine Facilitates Proton Transfer during Dioxygen Activation at the Diiron Center of Toluene/o-Xylene Monooxygenase Hydroxylase
(American Chemical Society, 2010-10)Toluene/o-xylene monooxygenase hydroxylase (ToMOH), a diiron-containing enzyme, can activate dioxygen to oxidize aromatic substrates. To elucidate the role of a strictly conserved T201 residue during dioxygen activation ... -
Active Social Media Management: The Case of Health Care
(Institute for Operations Research and the Management Sciences (INFORMS), 2013-03)Given the demand for authentic personal interactions over social media, it is unclear how much firms should actively manage their social media presence. We study this question empirically in a health care setting. We show ... -
Active Spanning Trees with Bending Energy on Planar Maps and SLE-Decorated Liouville Quantum Gravity for 𝜅 > 8
(Springer Science and Business Media LLC, 2018-02)We introduce a two-parameter family of probability measures on spanning trees of a planar map. One of the parameters controls the activity of the spanning tree and the other is a measure of its bending energy. When the ...
