518 research outputs found
Ultrafast Collective Dynamics in the Charge-Density-Wave Conductor KMoO
Low-energy coherent charge-density wave excitations are investigated in blue
bronze (KMoO) and red bronze (KMoO) by femtosecond
pump-probe spectroscopy. A linear gapless, acoustic-like dispersion relation is
observed for the transverse phasons with a pronounced anisotropy in
KMoO. The amplitude mode exhibits a weak (optic-like) dispersion
relation with a frequency of 1.67 THz at 30 K. Our results show for the first
time that the time-resolved optical technique provides momentum resolution of
collective excitations in strongly correlated electron systems.Low-energy
coherent charge-density wave excitations are investigated in blue bronze
(KMoO) and red bronze (KMoO) by femtosecond
pump-probe spectroscopy. A linear gapless, acoustic-like dispersion relation is
observed for the transverse phasons with a pronounced anisotropy in
KMoO. The amplitude mode exhibits a weak (optic-like) dispersion
relation with a frequency of 1.67 THz at 30 K. Our results show for the first
time that the time-resolved optical technique provides momentum resolution of
collective excitations in strongly correlated electron systems.Comment: 10 pages, 4 figure
Mega-Reward: Achieving Human-Level Play without Extrinsic Rewards
Intrinsic rewards were introduced to simulate how human intelligence works;
they are usually evaluated by intrinsically-motivated play, i.e., playing games
without extrinsic rewards but evaluated with extrinsic rewards. However, none
of the existing intrinsic reward approaches can achieve human-level performance
under this very challenging setting of intrinsically-motivated play. In this
work, we propose a novel megalomania-driven intrinsic reward (called
mega-reward), which, to our knowledge, is the first approach that achieves
human-level performance in intrinsically-motivated play. Intuitively,
mega-reward comes from the observation that infants' intelligence develops when
they try to gain more control on entities in an environment; therefore,
mega-reward aims to maximize the control capabilities of agents on given
entities in a given environment. To formalize mega-reward, a relational
transition model is proposed to bridge the gaps between direct and latent
control. Experimental studies show that mega-reward (i) can greatly outperform
all state-of-the-art intrinsic reward approaches, (ii) generally achieves the
same level of performance as Ex-PPO and professional human-level scores, and
(iii) has also a superior performance when it is incorporated with extrinsic
rewards
Granular computing and optimization model-based method for large-scale group decision-making and its application
In large-scale group decision-making process, some decision makers hesitate among several linguistic terms and cannot compare
some alternatives, so they often express evaluation information
with incomplete hesitant fuzzy linguistic preference relations.
How to obtain suitable large-scale group decision-making results
from incomplete preference information is an important and
interesting issue to concern about. After analyzing the existing
researches, we find that: i) the premise that complete preference
relation is perfectly consistent is too strict, ii) deleting all incomplete linguistic preference relations that cannot be fully completed will lose valid assessment information, iii) semantics given
by decision makers are greatly possible to be changed during the
consistency improving process. In order to solve these issues, this
work proposes a novel method based on Granular computing
and optimization model for large-scale group decision-making,
considering the original consistency of incomplete hesitant fuzzy
linguistic preference relation and improving its consistency without changing semantics during the completion process. An illustrative example and simulation experiments demonstrate the
rationality and advantages of the proposed method: i) semantics
are not changed during the consistency improving process, ii)
completion process does not significantly alter the inherent quality of information, iii) complete preference relations are globally
consistent, iv) final large-scale group decision-making result is
acquired by fusing complete preference relations with different weights
Towards Visual Saliency Explanations of Face Recognition
Deep convolutional neural networks have been pushing the frontier of face
recognition (FR) techniques in the past years. Despite the high accuracy, they
are often criticized for lacking explainability. There has been an increasing
demand for understanding the decision-making process of deep face recognition
systems. Recent studies have investigated using visual saliency maps as an
explanation, but they often lack a discussion and analysis in the context of
face recognition. This paper conceives a new explanation framework for face
recognition. It starts by providing a new definition of the saliency-based
explanation method, which focuses on the decisions made by the deep FR model.
Then, a novel correlation-based RISE algorithm (CorrRISE) is proposed to
produce saliency maps, which reveal both the similar and dissimilar regions of
any given pair of face images. Besides, two evaluation metrics are designed to
measure the performance of general visual saliency explanation methods in face
recognition. Consequently, substantial visual and quantitative results have
shown that the proposed method consistently outperforms other explainable face
recognition approaches
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