scholarly journals Intensity Evolution of Cosine-Gaussian-Correlated Schell-Model Pulse Scattered by a Medium

2020 ◽  
Vol 10 (5) ◽  
pp. 1825
Author(s):  
Haixia Wang ◽  
Xumin Yan ◽  
Xiaotong Feng ◽  
Zhiguo Zhao ◽  
Liuzhan Pan
Keyword(s):  
Born Approximation ◽  
Angular Width ◽  
First Order ◽  
Partially Coherent ◽  
Beam Scattering ◽  
Potential Applications ◽  
Coherent Pulse ◽  
Analytic Expression ◽  
Similarities And Differences ◽  
Intensity Evolution

According to first-order Born approximation, the scattering of a partially coherent pulse with cosine-Gaussian correlation by a medium was studied. On the basis of analytic expression, the changes in intensity evolution of the scattered pulse are discussed. The influences of pulse and medium characteristics on the intensity of the scattered pulse were investigated. The intensities of a Gaussian Schell-model (GSM) pulse and a cosine-Gaussian-correlated Schell-model (CGSM) pulse, both scattered by the same medium, are compared, and their similarities and differences are examined in detail. The effective angular width of the scattered pulse could be modulated by the parameters of the pulse and medium. The obtained results could find potential applications in pulsed beam scattering.

scholarly journals Efficient Graph Collaborative Filtering via Contrastive Learning

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4666
Author(s):  
Zhiqiang Pan ◽  
Honghui Chen
Keyword(s):  
Collaborative Filtering ◽  
State Of The Art ◽  
Representation Learning ◽  
First Order ◽  
Satisfactory Performance ◽  
Potential Applications ◽  
Benchmark Datasets ◽  
Bayesian Personalized Ranking ◽  
Graph Neural Networks ◽  
Training Efficiency

Collaborative filtering (CF) aims to make recommendations for users by detecting user’s preference from the historical user–item interactions. Existing graph neural networks (GNN) based methods achieve satisfactory performance by exploiting the high-order connectivity between users and items, however they suffer from the poor training efficiency problem and easily introduce bias for information propagation. Moreover, the widely applied Bayesian personalized ranking (BPR) loss is insufficient to provide supervision signals for training due to the extremely sparse observed interactions. To deal with the above issues, we propose the Efficient Graph Collaborative Filtering (EGCF) method. Specifically, EGCF adopts merely one-layer graph convolution to model the collaborative signal for users and items from the first-order neighbors in the user–item interactions. Moreover, we introduce contrastive learning to enhance the representation learning of users and items by deriving the self-supervisions, which is jointly trained with the supervised learning. Extensive experiments are conducted on two benchmark datasets, i.e., Yelp2018 and Amazon-book, and the experimental results demonstrate that EGCF can achieve the state-of-the-art performance in terms of Recall and normalized discounted cumulative gain (NDCG), especially on ranking the target items at right positions. In addition, EGCF shows obvious advantages in the training efficiency compared with the competitive baselines, making it practicable for potential applications.

Spectra and Coherence Properties of Partially Coherent Pulse Scattered by Anisotropic Media

2013 ◽  
Vol 33 (7) ◽  
pp. 0729001
Author(s):  
丁超亮 Ding Chaoliang ◽  
张永涛 Zhang Yongtao ◽  
王海霞 Wang Haixia ◽  
赵志国 Zhao Zhiguo ◽  
潘留占 Pan Liuzhan
Keyword(s):  
Anisotropic Media ◽  
Partially Coherent ◽  
Coherent Pulse

Interpreting and minority language planning and policy

2013 ◽  
Vol 37 (3) ◽  
pp. 227-248 ◽  
Author(s):  
Robert Neal Baxter
Keyword(s):  
Language Planning ◽  
Minority Language ◽  
Minority Languages ◽  
Language Planning And Policy ◽  
Linguistic Rights ◽  
Oral Interpretation ◽  
Potential Applications ◽  
Similarities And Differences

With potential applications for other minority languages, this paper discusses the implications of interpreting to and from Galician, starting with an overview of the current sociolinguistic situation, and the interpreting and translation market in Galicia in the light of political changes. After highlighting the similarities and differences between written translation and oral interpretation, the article examines the role played specifically by interpretation as a prestige-raising activity within the framework of language planning. Finally, the paper also discusses interpreting using minority languages as a tool enabling citizens to exercise their linguistic rights to the full.

Spatially and spectrally resolved ultra-narrowband TE-polarization absorber based on the guide-mode resonance

2017 ◽  
Vol 31 (24) ◽  
pp. 1750223
Author(s):  
Yan-Lin Liao ◽  
Yan Zhao ◽  
Xingfang Zhang ◽  
Wen Zhang ◽  
Zhongzhu Wang
Keyword(s):  
Normal Incidence ◽  
Optical Filters ◽  
Grating Period ◽  
Angle Measurement ◽  
Angular Width ◽  
Dielectric Grating ◽  
Guide Mode ◽  
Potential Applications ◽  
Polarization Electric Field ◽  
Spectrally Resolved

A spatially and spectrally resolved ultra-narrowband absorber with a dielectric grating and metal substrate has been reported. The absorber shows that the absorption rate is more than 0.99 with the absorption bandwidth less than 1.5 nm at normal incidence for TE polarization (electric field is parallel to grating grooves). The angular width of the absorption is about 0.27[Formula: see text]. The wavelength-angle sensitivity and absorption-angle sensitivity are 13.4 nm per degree and 296.3% per degree, respectively. The simulation results also show the spatially and spectrally resolved ultra-narrowband absorption is originated from the guide-mode resonance. In addition, the wavelength-angle sensitivity can be improved by enlarging the grating period according to the guide-mode resonance mechanism. The proposed absorber has potential applications in optical filters, angle measurement and thermal emitters.

Analysis without actual infinity

1981 ◽  
Vol 46 (3) ◽  
pp. 625-633 ◽  
Author(s):  
Jan Mycielski
Keyword(s):  
Natural Science ◽  
Order Theory ◽  
Finite Part ◽  
Consistency Proof ◽  
Actual Infinity ◽  
First Order ◽  
Finite Models ◽  
First Order Theory ◽  
Potential Applications

AbstractWe define a first-order theory FIN which has a recursive axiomatization and has the following two properties. Each finite part of FIN has finite models. FIN is strong enough to develop that part of mathematics which is used or has potential applications in natural science. This work can also be regarded as a consistency proof of this hitherto informal part of mathematics. In FIN one can count every set; this permits one to prove some new probabilistic theorems.

Born non-scattering electromagnetic media

2017 ◽  
Vol 25 (4) ◽  
Author(s):  
Tilo Arens ◽  
John Sylvester
Keyword(s):  
Born Approximation ◽  
Electromagnetic Waves ◽  
Variational Equation ◽  
Plane Waves ◽  
Transformation Optics ◽  
Local Perturbation ◽  
Detectable Change ◽  
Scattering Media ◽  
First Order

AbstractWe consider the propagation of electromagnetic waves in an anisotropic medium. A local perturbation of the vacuum media that does not produce a detectable change in the far field is called non-scattering. Through testing by plane waves, we derive a variational equation characterizing non-scattering perturbations of permittivities and permeabilities to first order, i.e. in the Born approximation. We show that these perturbations can be characterized exactly by four functions. Three of these functions correspond to linearizations of known non-scattering media constructed by diffeomorphisms in transformation optics. The role of the fourth function is not yet understood, although some analytic properties can be derived.

scholarly journals Moving breathers and breather-to-soliton conversions for the Hirota equation

2015 ◽  
Vol 471 (2180) ◽  
pp. 20150130 ◽  
Author(s):  
A. Chowdury ◽  
A. Ankiewicz ◽  
N. Akhmediev
Keyword(s):  
Schrodinger Equation ◽  
Higher Order ◽  
Nonlinear Schrodinger Equation ◽  
Second Order ◽  
Periodic Oscillations ◽  
Hirota Equation ◽  
First Order ◽  
Special Values ◽  
Analytic Expression ◽  
Free Parameters

We find that the Hirota equation admits breather-to-soliton conversion at special values of the solution eigenvalues. This occurs for the first-order, as well as higher orders, of breather solutions. An analytic expression for the condition of the transformation is given and several examples of transformations are presented. The values of these special eigenvalues depend on two free parameters that are present in the Hirota equation. We also find that higher order breathers generally have complicated quasi-periodic oscillations along the direction of propagation. Various breather solutions are considered, including the particular case of second-order breathers of the nonlinear Schrödinger equation.

scholarly journals Improved and isotropic resolution in tomographic diffractive microscopy combining sample and illumination rotation

Open Physics ◽  
2011 ◽  
Vol 9 (4) ◽  
Author(s):  
Stanislas Vertu ◽  
Jens Flügge ◽  
Jean-Jacques Delaunay ◽  
Olivier Haeberlé
Keyword(s):  
Frequency Domain ◽  
Born Approximation ◽  
Three Dimensions ◽  
Maximal Extension ◽  
Isotropic Resolution ◽  
First Order ◽  
Illumination Method

AbstractTomographic Diffractive Microscopy is a technique, which permits to image transparent living specimens in three dimensions without staining. It is commonly implemented in two configurations, by either rotating the sample illumination keeping the specimen fixed, or by rotating the sample using a fixed illumination. Under the first-order Born approximation, the volume of the frequency domain that can be mapped with the rotating illumination method has the shape of a “doughnut”, which exhibits a so-called “missing cone” of non-captured frequencies, responsible for the strong resolution anisotropy characteristic of transmission microscopes. When rotating the sample, the resolution is almost isotropic, but the set of captured frequencies still exhibits a missing part, the shape of which resembles that of an apple core. Furthermore, its maximal extension is reduced compared to tomography with rotating illumination. We propose various configurations for tomographic diffractive microscopy, which combine both approaches, and aim at obtaining a high and isotropic resolution. We illustrate with simulations the expected imaging performances of these configurations.

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