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6th International Conference on Optoelectronic Science and Materials, ICOSM 2024

作者： Zhang, Zhiyuan Li, Chongguang Lou, Yuli Liu, Siqi Liang, Xiyuan Song, Qinghe Gui, Jinbin Key Laboratory of Laser Information Processing Technology and Application College of Science Kunming University of Science and Technology Yunnan Kunming650500 China

ISBN: (数字)9781510686823

ISBN: (纸本)9781510686816

In the study of optical systems, accurately calculating Fresnel diffraction patterns is crucial for understanding and designing various applications, from imaging systems to laser technologies. However, existing commonly used calculation methods each have their limitations. This paper proposes an approximate algorithm for calculating Fresnel diffraction to address these shortcomings. The algorithm is based on the oscillatory characteristics of the quadratic phase exponential function in the Fresnel diffraction integral. By convolving this quadratic phase exponential function with another slowly varying function, it is found that the rapidly oscillating parts cancel each other out, having little impact on the final calculation result. Therefore, only the areas that primarily contribute to the diffraction need to be computed. The study shows that this algorithm significantly reduces the computational load while maintaining a certain level of accuracy. Compared to the direct integration method, it shows a notable improvement in calculation speed. It also maintains high accuracy compared to both the direct integration method and the Fast Fourier Transform (FFT) algorithm. Additionally, since it does not involve the frequency domain transformation used in FFT, it avoids under-sampling issues. This algorithm offers a feasible method for calculating diffraction patterns while ensuring a balance between accuracy and computational efficiency. © 2024 SPIE.

关键词： Exponential functions

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Experiment on protection performance of plasma array to 6GHz high-power microwave

Experiment on protection performance of plasma array to 6GHz...

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2023 Advanced Fiber laser Conference, AFL 2023

作者： Liu, Yang Lv, Shouye Li, Jinzhou Meng, Gang Liao, Shuai Shi, Jiaming Satellite Information Intelligent Processing and Application Research Laboratory Beijing Institute of Remote Sensing Information Beijing100192 China State Key Laboratory of Pulsed Power Laser Technology National University of Defense Technology Hefei230037 China

ISBN: (纸本)9781510677661

For purpose of the electromagnetic pulse (EMP) protection research, a double-layer barrier of cylindrical plasma array was designed, and its protective performance to 6GHz high-power microwave (HPM) was conducted experimentally. Combining the distribution of the discharge plasma array, the shielding effectiveness of the double-layer plasma on 6GHz HPM pulse was studied. The main research contents and conclusions are as follows: The transmission energy of HPM decreased as the increase of plasma electron density, indicating an improved protection effect, with both double-layer and single-layer plasma array. Besides, the results showed that the transmission attenuation of HPM in double-layer structure was greater than that in single-layer structure because of the interlayer reflection. In addition, an interesting phenomenon was discovered during the experiment, which was that the boundary plasma units had a significant impact on the HPM transmission. The shielding effect of HPM was better with opening seven plasma units than that with opening whole plasma array. Finally, the spectral characteristics and transmission coefficients of the HPM were presented by Fourier transform, and the results of the protective performance were consistent with the above-mentioned time-domain analysis. The experiment results in this paper are of great significance in protecting against HPM based on plasma. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

关键词： Carrier concentration

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Terahertz Frequency Reconfigurable Slot Antenna Based on Graphene 4

Terahertz Frequency Reconfigurable Slot Antenna Based on Gra...

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4th International Conference on Electronics, Circuits and information Engineering, ECIE 2024

作者： Wu, Qinglin Cao, Weiping Wang, Qingyong Luo, Yumei Guilin University of Electronic Science and Technology School of Information and Communications Gui Lin China Guilin University of Electronic Science and Technology Guangxi Key Lab of Wireless Wideband Communication and Signal Processing School of Information and Communications Gui Lin China Guilin University of Electronic Technology Guangxi Key Laboratory of Precision Navigation Technology and Application Gui Lin China

ISBN: (纸本)9798350388312

Toaddress the demands of high data rate transmission, multifunctionality, and miniaturization in modern communication devices, a novel design for a frequency-reconfigurable terahertz patch antenna is proposed using graphene. The antenna employs a coplanar waveguide feeding structure, which facilitates impedance matching. Three graphene patches are strategically placed and serve as tuning switches within the antenna gap. By controlling the conductivity of graphene, the effective length of the antenna is influenced, enabling frequency switching. The antenna achieves frequency reconfigurable within the 2.705- 3.569 THz frequency range, exhibits good impedance matching, with reflection coefficients all below -17 dB, and maintains a stable maximum radiation gain within 2.9-3.1 dBi. © 2024 IEEE.

关键词： Coplanar waveguides

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Large Language Models are Good Attackers: Efficient and Stealthy Textual Backdoor Attacks

arXiv

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arXiv 2024年

作者： Li, Ziqiang Zeng, Yueqi Xia, Pengfei Liu, Lei Fu, Zhangjie Li, Bin Nanjing University of Information Science and Technology China Big Data and Decision Lab University of Science and Technology of China China CAS Key Laboratory of Technology in Geo-spatial Information Processing and Application System China

With the burgeoning advancements in the field of natural language processing (NLP), the demand for training data has increased significantly. To save costs, it has become common for users and businesses to outsource the labor-intensive task of data collection to third-party entities. Unfortunately, recent research has unveiled the inherent risk associated with this practice, particularly in exposing NLP systems to potential backdoor attacks. Specifically, these attacks enable malicious control over the behavior of a trained model by poisoning a small portion of the training data. Unlike backdoor attacks in computer vision, textual backdoor attacks impose stringent requirements for attack stealthiness. However, existing attack methods meet significant trade-off between effectiveness and stealthiness, largely due to the high information entropy inherent in textual data. In this paper, we introduce the Efficient and Stealthy Textual backdoor attack method, EST-Bad, leveraging Large Language Models (LLMs). Our EST-Bad encompasses three core strategies: optimizing the inherent flaw of models as the trigger, stealthily injecting triggers with LLMs, and meticulously selecting the most impactful samples for backdoor injection. Through the integration of these techniques, EST-Bad demonstrates an efficient achievement of competitive attack performance while maintaining superior stealthiness compared to prior methods across various text classifier datasets. © 2024, CC BY.

关键词： Deep neural networks

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Rich-text document styling restoration via reinforcement learning

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Frontiers of Computer Science 2021年第4期15卷 93-103页

作者： Hongwei LI Yingpeng HU Yixuan CAO Ganbin ZHOU Ping LUO Key Lab of Intelligent Information Processing of Chinese Academy of Sciences(CAS) Institute of Computing TechnologyCASBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Search Product Center WeChat Search Application DepartmentTencentBeijing 100080China

Richly formatted documents,such as financial disclosures,scientific articles,government regulations,widely exist on ***,since most of these documents are only for public reading,the styling information inside them is usually missing,making them improper or even burdensome to be displayed and edited in different formats and *** this study we formulate the task of document styling restoration as an optimization problem,which aims to identify the styling settings on the document elements,e.g.,lines,table cells,text,so that rendering with the output styling settings results in a document,where each element inside it holds the(closely)exact position with the one in the original *** that each styling setting is a decision,this problem can be transformed as a multi-step decision-making task over all the document elements,and then be solved by reinforcement ***,Monte-Carlo Tree Search(MCTS)is leveraged to explore the different styling settings,and the policy function is learnt under the supervision of the delayed *** a case study,we restore the styling information inside tables,where structural and functional data in the documents are usually *** shows that,our best reinforcement method successfully restores the stylings in 87.65%of the tables,with 25.75%absolute improvement over the *** also discuss the tradeoff between the inference time and restoration success rate,and argue that although the reinforcement methods cannot be used in real-time scenarios,it is suitable for the offline tasks with high-quality ***,this model has been applied in a PDF parser to support cross-format display.

关键词： styling restoration monte-carlo tree search reinforcement learning richly formatted documents tables

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Two-Stage OD Flow Prediction for Emergency in Urban Rail Transit

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IEEE Transactions on Intelligent Transportation Systems 2024年第1期25卷 920-928页

作者： Zhu, Guangyu Ding, Jiacun Wei, Yun Yi, Yang Xu, Sendren Sheng-Dong Wu, Edmond Q. Beijing Jiaotong University Key Lab. of Transport Industry of Big Data Application Technologies for Comprehensive Transport The Beijing Research Center of Urban Traffic Information Sensing and Service Technologies Beijing100044 China Beijing Mass Transit Railway Operation Corporation Ltd. Beijing100014 China Yangzhou University College of Information Engineering Yangzhou225127 China National Taiwan University of Science and Technology Automation and Control Center The Graduate Institute of Automation and Control Taipei106335 Taiwan Shanghai Jiao Tong University Key Laboratory of System Control and Information Processing Ministry of Education of China The Shanghai Engineering Research Center of Intelligent Control and Management Department of Automation Shanghai200240 China

Urban rail transit (URT) is vulnerable to natural disasters and social emergencies including fire, storm and epidemic (such as COVID-19), and real-time origin-destination (OD) flow prediction provides URT operators with important information to ensure the safety of URT system. However, hindered by the high dimensionality of OD flow and the lack of supportive information reflecting the real-time passenger flow changes, study in this area is at the beginning stage. A novel model consisting of two stages is proposed for OD flow prediction. The first stage predicts the inflows of all stations by Long Short-Term Memory (LSTM) in real time, where the dimension is reduced compared with predicting OD flows directly. In the second stage, the notion of separation rate, namely, the proportion of inbound passengers bounding for another station, is estimated. Finally, The OD flow is predicted by multiplying the inflow and separation rate. Experiments based on Hangzhou Metro dataset show the proposed model outperforms the contrast model in weighted mean average error (WMAE) and weighted mean square error (WMSE). Results also suggest that the proposed prediction model performs better on weekdays than on weekends, and with greater accuracy on larger OD flows. © 2000-2011 IEEE.

关键词： Forecasting

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Terahertz Frequency Reconfigurable Slot Antenna Based on Graphene

Terahertz Frequency Reconfigurable Slot Antenna Based on Gra...

引用

Electronics, Circuits and information Engineering (ECIE), International Conference on

作者： Qinglin Wu Weiping Cao Qingyong Wang Yumei Luo School of Information and Communications Guilin University of Electronic Science and Technology Gui Lin China Guangxi Key Lab of Wireless Wideband Communication and Signal Processing School of Information and Communications Guilin University of Electronic Science and Technology Gui Lin China Guangxi Key Laboratory of Precision Navigation Technology and Application Guilin University of Electronic Technology Gui Lin China

ISBN: (数字)9798350388312

ISBN: (纸本)9798350388329

关键词： Slot antennas Impedance matching Graphene Resonant frequency Terahertz radiation Switches Antennas

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Evolution of defect polarization under external fields in potassium sodium niobate-based ceramics with excess bismuth

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Ceramics International 2025年

作者： Tao, Hong Wu, Wenjuan Zhao, Chunlin Zhang, Yiting Song, Xilong Feng, Jiaqing Xing, Zhipeng Wu, Chaofeng Zhao, Lin Wu, Bo Ma, Jian Xu, Ze Sichuan Prov Key Lab Informat Mat Southwest Minzu University Chengdu610041 China Sichuan Province Key Laboratory of Information Materials and Devices Application Chengdu University of Information Technology Chengdu610225 China College of Materials Science and Engineering Fuzhou University Fuzhou350108 China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing100084 China Tongxiang Tsingfeng Technology Co. Ltd Jiaxing314500 China

Piezoelectric ultrasonic motors play a pivotal role in advancing intelligent and high-tech applications, drawing significant attention to the study of defects in piezoelectric materials. Defect modulation, achieved through the incorporation of appropriate additives, stands out as a proven and effective strategy for enhancing the performance of ceramics. Herein, defect structure and the orientation behavior under external fields has been emphasized on in potassium sodium niobate ceramics with excess bismuth. Elevated defect polarization is revealed with increased A-site vacancy and decreased oxygen vacancy when bismuth is strongly excessive, along with lowered orthorhombic-tetragonal phase transition temperature. The defect polarization is oriented under a high electric field and depolarized under a strong thermal field. This is evidenced by asymmetric ferroelectric hysteresis loops and a large internal bias field in poled ceramics, while unpoled and depolarized samples display nearly symmetrical loops. Additionally, asymmetric bipolar strain curves with a notable deviation between positive and negative electric fields are observed in poled samples, whereas annealing reduces this asymmetry. Meanwhile, the domain switching becomes more difficult in the poled state compared to the virgin state due to the pinning effect induced by oriented defect polarization during pre-poling. Then, large Qm and d33 as well as decreasing and increasing tendencies respectively, are gained simultaneously with increased defect, generated by the strong promoted domain switching from elevated A-site vacancy and lowered phase transition temperature, with respect to the impeded effect from pinning effect of defect dipoles. Therefore, this study demonstrated the defect evolution under external fields and the impact on macro-performance, accelerating the material development for piezoelectric motors. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Piezoelectric motors

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Peer is Your Pillar: A Data-unbalanced Conditional GANs for Few-shot Image Generation

arXiv

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arXiv 2023年

作者： Li, Ziqiang Wang, Chaoyue Rui, Xue Xue, Chao Leng, Jiaxu Li, Bin Big Data and Decision Lab University of Science and Technology of China China The University of Sydney Australia JD Explore Academic China School of computer science Chongqing University of Posts and Telecommunications China CAS Key Laboratory of Technology in Geo-spatial Information Processing and Application System China

Few-shot image generation aims to train generative models using a small number of training images. When there are few images available for training (e.g. 10 images), Learning From Scratch (LFS) methods often generate images that closely resemble the training data while Transfer Learning (TL) methods try to improve performance by leveraging prior knowledge from GANs pre-trained on large-scale datasets. However, current TL methods may not allow for sufficient control over the degree of knowledge preservation from the source model, making them unsuitable for setups where the source and target domains are not closely related. To address this, we propose a novel pipeline called Peer is your Pillar (PIP), which combines a target few-shot dataset with a peer dataset to create a data-unbalanced conditional generation. Our approach includes a class embedding method that separates the class space from the latent space, and we use a direction loss based on pre-trained CLIP to improve image diversity. Experiments on various few-shot datasets demonstrate the advancement of the proposed PIP, especially reduces the training requirements of few-shot image generation. © 2023, CC BY.

关键词： Large dataset

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Study of Composition-Modulated Interband Transitions Characteristic and Charge Dynamics Response of High-Throughput FeSe1-xTex Combinatorial Film

SSRN

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SSRN 2024年

作者： Wang, Yueming Wei, Mingyang Li, Yongfu Jin, Kui Lin, Zefeng Zhou, Xiang'an Han, Yating Guan, Xiangyun Lian, Jie School of Information Science and Engineering Shandong Provincial Key Laboratory of Laser Technology and Application Shandong University Qingdao266237 China Center for Optics Research and Engineering Key Laboratory of Laser & Infrared System Ministry of Education Shandong University Qingdao266237 China National Lab for Superconductivity Institute of Physics Chinese Academy of Sciences Beijing100190 China Department of Basic Shandong Urban Construction Vocational College Jinan250100 China

FeSe is regarded as a strong correlation system of simple structure and remarkable tunability in the superconducting transition temperature (Tc). Particularly, the substitution of Se with its isoelectronic Te leads to a dome-shaped Tc evolution, positioning the FeSe1-xTex as an ideal platform for exploring the mechanism of iron-based superconductivity. In this study, we employed high-throughput combinatorial molecular beam epitaxy (CLMBE) to fabricate high-quality FeSe1-xTex film with horizontal gradient. The dielectric spectra of FeSe1-xTex were obtained by ellipsometry spectroscopy (SE). We utilized the standard critical point model and first-principles calculation to identify that the observed interband transitions are predominantly sourced from Fe-3d near the Fermi surface. The pseudogap, extracted from the transitions, shows a bowl-like trend as increased Te, which is negatively correlated with Tc, suggesting a qualitative way to predict Tc in the normal-state. The composition-dependent charge dynamics response, derived from Drude oscillators in SE, indicates that electron-electron interactions might play a more substantial role in FeSe1-xTex superconductivity, combined with the unidirectional electron-phonon coupling result in Raman. The variation of plasma frequency and photoinduced carrier dispersion under composition modulation demonstrates the effect of Te in enhancing system interactions, providing valuable support for the design of superconducting optoelectronic devices. © 2024, The Authors. All rights reserved.

关键词： Iron compounds

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