8,836 research outputs found
Flow-based Intrinsic Curiosity Module
In this paper, we focus on a prediction-based novelty estimation strategy
upon the deep reinforcement learning (DRL) framework, and present a flow-based
intrinsic curiosity module (FICM) to exploit the prediction errors from optical
flow estimation as exploration bonuses. We propose the concept of leveraging
motion features captured between consecutive observations to evaluate the
novelty of observations in an environment. FICM encourages a DRL agent to
explore observations with unfamiliar motion features, and requires only two
consecutive frames to obtain sufficient information when estimating the
novelty. We evaluate our method and compare it with a number of existing
methods on multiple benchmark environments, including Atari games, Super Mario
Bros., and ViZDoom. We demonstrate that FICM is favorable to tasks or
environments featuring moving objects, which allow FICM to utilize the motion
features between consecutive observations. We further ablatively analyze the
encoding efficiency of FICM, and discuss its applicable domains
comprehensively.Comment: The SOLE copyright holder is IJCAI (International Joint Conferences
on Artificial Intelligence), all rights reserved. The link is provided as
follows: https://www.ijcai.org/Proceedings/2020/28
Tubular Organization of SnO2 Nanocrystallites for Improved Lithium Ion Battery Anode Performace
Porous tin oxide nanotubes were obtained by vacuum infiltration of tin oxide nanoparticles into porous aluminum oxide membranes, followed by calcination. The porous tin oxide nanotube arrays so prepared were characterized by FE-SEM, TEM, HRTEM, and XRD. The nanotubes are open-ended, highly ordered with uniform cross-sections, diameters and wall thickness. The tin oxide nanotubes were evaluated as a substitute anode material for the lithium ion batteries. The tin oxide nanotube anode could be charged and discharged repeatedly, retaining a specific capacity of 525 mAh/g after 80 cycles. This capacity is significantly higher than the theoretical capacity of commercial graphite anode (372 mAh/g) and the cyclability is outstanding for a tin based electrode. The cyclability and capacities of the tin oxide nanotubes were also higher than their building blocks of solid tin oxide nanoparticles. A few factors accounting for the good cycling performance and high capacity of tin oxide nanotubes are suggested.Singapore-MIT Alliance (SMA
Template Synthesis of Tubular Sn-Based Nanostructures for Lithium Ion Storage
We report herewith the preparation of SnOâ‚‚ nanotubes with very good shape and size control, and with and without a carbon nanotube overlayer, The SnOâ‚‚-core/carbon-shell nanotubes are excellent reversible Li ion storage compounds combining the best features of carbon (cyclability) and SnOâ‚‚ (capacity) to deliver a high specific capacity (~540-600 mAh/g) simultaneous with good cyclability (0.0375% capacity loss per cycle).Singapore-MIT Alliance (SMA
The strangeness form factors of the proton within nonrelativistic constituent quark model revisited
We reexamine, within the nonrelativistic constituent quark model (NRCQM), a
recent claim that the current data on the strangeness form factors indicates
that the uuds\bar{s} component in the proton is such that the uuds subsystem
has the mixed spatial symmetry [31]_X and flavor spin symmetry
[4]_{FS}[22]_F[22]_S, with \bar{s} in S state (configuration I). We find this
claim to be invalid if corrected expressions for the contributions of the
transition current to G_A^s and G_E^s are used. We show that, instead, it is
the lowest-lying uuds\bar{s} configuration with uuds subsystem of completely
symmetric spatial symmetry [4]_X and flavor spin symmetry [4]_{FS}[22]_F[22]_S,
with \bar{s} in P state (configuration II), which could account for the
empirical signs of all form factors G_E^s, G_M^s, and G_A^s. Further, we find
that removing the center-of-mass motion of the clusters will considerably
enhance the contributions of the transition current. We also demonstrate that
it is possible to give a reasonable description of the existing form factors
data with a tiny probability P_{s\bar{s}}=0.025% for the uuds\bar{s} component.
We further see that with a small admixture of configuration I, the agreement of
our prediction with data for G_A^s at low-q^2 region can be markedly improved.
We find that without removing CM motion, P_{s\bar{s}} would be overestimated by
about a factor of four in the case when transition current dominates. We also
explore the consequence of a recent estimate reached from analyzing existing
data on \bar{d} -\bar{u}, s +\bar{s}, and \bar{u} + \bar{d} - s -\bar{s}, that
P_{s\bar{s}} lies between 2.4-2.9%. It would lead to a large size for the
five-quark system and a small bump in both G_E^s+\eta G_M^s and G_E^s in the
region of q^2<=0.1 GeV^2 within the considered model.Comment: 6 pages, 2 figure
Phase sensitivity at the Heisenberg limit in an SU(1,1) interferometer via parity detection
We theoretically investigate the phase sensitivity with parity detection on
an SU(1,1) interferometer with a coherent state combined with a squeezed vacuum
state. This interferometer is formed with two parametric amplifiers for beam
splitting and recombination instead of beam splitters. We show that the
sensitivity of estimation phase approaches Heisenberg limit and give the
corresponding optimal condition. Moreover, we derive the quantum Cram\'er-Rao
bound of the SU(1,1) interferometer.Comment: 9 pages, 2 figures, 3 table
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