8,473 research outputs found
Quantum thermodynamics in a multipartite setting: A resource theory of local Gaussian work extraction for multimode bosonic systems
Quantum thermodynamics can be cast as a resource theory by considering free
access to a heat bath, thereby viewing the Gibbs state at a fixed temperature
as a free state and hence any other state as a resource. Here, we consider a
multipartite scenario where several parties attempt at extracting work locally,
each having access to a local heat bath (possibly with a different
temperature), assisted with an energy-preserving global unitary. As a specific
model, we analyze a collection of harmonic oscillators or a multimode bosonic
system. Focusing on the Gaussian paradigm, we construct a reasonable resource
theory of local activity for a multimode bosonic system, where we identify as
free any state that is obtained from a product of thermal states (possibly at
different temperatures) acted upon by any linear-optics (passive Gaussian)
transformation. The associated free operations are then all linear-optics
transformations supplemented with tensoring and partial tracing. We show that
the local Gaussian extractable work (if each party applies a Gaussian unitary,
assisted with linear optics) is zero if and only if the covariance matrix of
the system is that of a free state. Further, we develop a resource theory of
local Gaussian extractable work, defined as the difference between the trace
and symplectic trace of the covariance matrix of the system. We prove that it
is a resource monotone that cannot increase under free operations. We also
provide examples illustrating the distillation of local activity and local
Gaussian extractable work.Comment: 22 pages, 5 figures, minor corrections to make it close to the
published version, updated list of reference
Coherent Doppler Wind Lidar Technology for Space Based Wind Measurements Including SPARCLE
It has been over 30 years since coherent lidar systems first measured wind velocity, and over 20 years since the "ultimate application" of measuring Earth's winds from space was conceived. Coherent or heterodyne optical detection involves the combination (or mixing) of the returned optical field with a local oscillator (LO) laser's optical field on the optical detector. This detection technique yields the benefits of dramatically improved signal-to-noise ratios; insensitivity to detector noise, background light and multiply scattered light; reduction of the returned signal's dynamic range; and preservation of the optical signal spectrum for electronic and computer processing. (Note that lidar systems are also referred to as optical radar, laser radar, and LADAR systems.) Many individuals, agencies, and countries have pursued the goal of space-based wind measurements through technology development, experiments, field campaigns and studies
Learning and Predicting Dynamic Behavior with Graphical Multiagent Models
Factored models of multiagent systems address the complexity of joint behavior by exploiting locality in agent interactions. History-dependent graphical multiagent models (hGMMs) further capture dynamics by conditioning behavior on history. The challenges of modeling real human behavior motivated us to extend the hGMM representation by distinguishing two types of agent interactions. This distinction opens the opportunity for learning dependence networks that are different from given graphical structures representing observed agent interactions. We propose a greedy algorithm for learning hGMMs from time-series data, inducing both graphical structure and parameters. Our empirical study employs human-subject experiment data for a dynamic consensus scenario, where agents on a network attempt to reach a unanimous vote. We show that the learned hGMMs directly expressing joint behavior outperform alternatives in predicting dynamic human voting behavior, and end-game vote results. Analysis of learned graphical structures reveals patterns of action dependence not directly reflected in the original experiment networks
Identifying First-person Camera Wearers in Third-person Videos
We consider scenarios in which we wish to perform joint scene understanding,
object tracking, activity recognition, and other tasks in environments in which
multiple people are wearing body-worn cameras while a third-person static
camera also captures the scene. To do this, we need to establish person-level
correspondences across first- and third-person videos, which is challenging
because the camera wearer is not visible from his/her own egocentric video,
preventing the use of direct feature matching. In this paper, we propose a new
semi-Siamese Convolutional Neural Network architecture to address this novel
challenge. We formulate the problem as learning a joint embedding space for
first- and third-person videos that considers both spatial- and motion-domain
cues. A new triplet loss function is designed to minimize the distance between
correct first- and third-person matches while maximizing the distance between
incorrect ones. This end-to-end approach performs significantly better than
several baselines, in part by learning the first- and third-person features
optimized for matching jointly with the distance measure itself
A starch edible surface coating delays banana fruit ripening
A rice starch edible coating blended with sucrose esters was developed for controlling the postharvest physiological activity of Cavendish banana to extend postharvest quality during ripening at 20 ± 2 °C. Coating effectiveness was assessed against changes in fruit physiochemical parameters such as weight loss, titratable acidity, total soluble solids, flesh fruit firmness, ion leakage, colour change, respiration, ethylene production, chlorophyll degradation and starch conversion were determined. The topography of coating material on the fruit surface was evaluated by scanning electron microscope (SEM). Surface morphology studies highlighted the binding compatibility of the coating matrix with the fruit peel character and formed a continuous uniform layer over the fruit surface. The results showed that the coating was effective in delaying ethylene biosynthesis and reducing respiration rate. Other factors impacting included delayed chlorophyll degradation, reduced weight loss and retention of fruit firmness for the first six days, all of which improved the commercial value of the fruit. The shelf life of coated fruit was prolonged for 12 days in comparison with the untreated control which ripened within seven days and lost marketability after Day 6. The pilot study demonstrates the effectiveness of a starch-based edible coating formulation for improving the ambient storage capacity of banana fruit
Superconductivity at 22 K in Co-doped BaFe2As2 Crystals
Here we report bulk superconductivity in BaFe1.8Co0.2As2 single crystals
below Tc = 22 K, as demonstrated by resistivity, magnetic susceptibility, and
specific heat data. Hall data indicate that the dominant carriers are
electrons, as expected from simple chemical reasoning. This is the first
example of superconductivity induced by electron doping in this family of
materials. In contrast to the cuprates, the BaFe2As2 system appears to tolerate
considerable disorder in the FeAs planes. First principles calculations for
BaFe1.8Co0.2As2 indicate the inter-band scattering due to Co is weak.Comment: 9 pages, 3 figure
Advances in Laser/Lidar Technologies for NASA's Science and Exploration Mission's Applications
NASA's Laser Risk Reduction Program, begun in 2002, has achieved many technology advances in only 3.5 years. The recent selection of several lidar proposals for Science and Exploration applications indicates that the LRRP goal of enabling future space-based missions by lowering the technology risk has already begun to be met
Enabling Laser and Lidar Technologies for NASA's Science and Exploration Mission's Applications
NASA s Laser Risk Reduction Program, begun in 2002, has achieved many technology advances in only 3.5 years. The recent selection of several lidar proposals for Science and Exploration applications indicates that the LRRP goal of enabling future space-based missions by lowering the technology risk has already begun to be met
Codes of ethics artefacts in Australia, Canada and Sweden : a longitudinal study
It would appear that corporations operating in Sweden have embraced the ethos of codes of ethics differently to their Canadian and/or Australian counterparts and that in each culture the way that companies fashion their approach to business ethics appears to be in line with their national, cultural values.<br /
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