1,121 research outputs found
A phase-field model of relaxor ferroelectrics based on random field theory
A mechanically coupled phase-field model is proposed for the first time to
simulate the peculiar behavior of relaxor ferroelectrics. Based on the random
field theory for relaxors, local random fields are introduced to characterize
the effect of chemical disorder. This generic model is developed from a
thermodynamic framework and the microforce theory and is implemented by a
nonlinear finite element method. Simulation results show that the model can
reproduce relaxor features, such as domain miniaturization, small remnant
polarization and large piezoelectric response. In particular, the influence of
random field strength on these features are revealed. Simulation results on
domain structure and hysteresis behavior are discussed and compared with
related experimental results.Comment: 8 figure
Optimization problems for general simple population with n-impulsive harvest
AbstractIn this paper, n-impulsive harvest problems of general simple population are discussed by models with Dirac function. The optimal impulsive harvest policies to protect the renewable resource better are obtained under conditions of fixed quantity per impulsive harvest. Then, a concept of the sequence for Ϝ-optimal harvest moments for general simple population is presented which is beneficial to protect resource better and sustainable development. Finally, we apply the conclusions to some special models
Use of a Green Familiar Faces Paradigm Improves P300-Speller Brain-Computer Interface Performance
Background A recent study showed improved performance of the P300-speller when the flashing row or column was overlaid with translucent pictures of familiar faces (FF spelling paradigm). However, the performance of the P300-speller is not yet satisfactory due to its low classification accuracy and information transfer rate. Objective To investigate whether P300-speller performance is further improved when the chromatic property and the FF spelling paradigm are combined. Methods We proposed a new spelling paradigm in which the flashing row or column is overlaid with translucent green pictures of familiar faces (GFF spelling paradigm). We analyzed the ERP waveforms elicited by the FF and proposed GFF spelling paradigms and compared P300-speller performance between the two paradigms. Results Significant differences in the amplitudes of four ERP components (N170, VPP, P300, and P600f) were observed between both spelling paradigms. Compared to the FF spelling paradigm, the GFF spelling paradigm elicited ERP waveforms of higher amplitudes and resulted in improved P300-speller performance. Conclusions Combining the chromatic property (green color) and the FF spelling paradigm led to better classification accuracy and an increased information transfer rate. These findings demonstrate a promising new approach for improving the performance of the P300-speller
A Study of Taxi Service Mode Choice Based on Evolutionary Game Theory
The emergence of online car-hailing service provides an innovative approach to vehicle booking but has negatively influenced the taxi industry in China. This paper modeled taxi service mode choice based on evolutionary game theory (EGT). The modes included the dispatching and online car-hailing modes. We constructed an EGT framework, including determining the strategies and the payoff matrix. We introduced different behaviors, including taxi company management, driver operation, and passenger choice. This allowed us to model the impact of these behaviors on the evolving process of service mode choice. The results show that adjustments in taxi company, driver, and passenger behaviors impact the evolutionary path and convergence speed of our evolutionary game model. However, it also reveals that, regardless of adjustments, the stable states in the game model remain unchanged. The conclusion provides a basis for studying taxi system operation and management.
Document type: Articl
Single Stage Virtual Try-on via Deformable Attention Flows
Virtual try-on aims to generate a photo-realistic fitting result given an
in-shop garment and a reference person image. Existing methods usually build up
multi-stage frameworks to deal with clothes warping and body blending
respectively, or rely heavily on intermediate parser-based labels which may be
noisy or even inaccurate. To solve the above challenges, we propose a
single-stage try-on framework by developing a novel Deformable Attention Flow
(DAFlow), which applies the deformable attention scheme to multi-flow
estimation. With pose keypoints as the guidance only, the self- and
cross-deformable attention flows are estimated for the reference person and the
garment images, respectively. By sampling multiple flow fields, the
feature-level and pixel-level information from different semantic areas are
simultaneously extracted and merged through the attention mechanism. It enables
clothes warping and body synthesizing at the same time which leads to
photo-realistic results in an end-to-end manner. Extensive experiments on two
try-on datasets demonstrate that our proposed method achieves state-of-the-art
performance both qualitatively and quantitatively. Furthermore, additional
experiments on the other two image editing tasks illustrate the versatility of
our method for multi-view synthesis and image animation.Comment: ECCV 202
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