检索结果-内蒙古大学图书馆

SSRN 2024年

作者： Xu, Biao Rang, Gejie Li, Wenji Gong, Dunwei Fan, Zhun Yang, Shengxiang He, Jie College of Engineering Shantou University Shantou515063 China College of Automation and Electronic Engineering Qingdao University of Science and Technology Qingdao266100 China Guangxi Key Laboratory of Machine Vision and Intelligent Control Wuzhou University Wuzhou543002 China Shenzhen institute for Advanced Study UESTC Shenzhen518110 China School of Computer Science and Informatics De Montfort University LeicesterLE1 9BH United Kingdom Minjiang University China

Dynamic multiobjective optimization problems (DMOPs) present significant challenges to conventional evolutionary optimization methods because of the continuous changes in their Pareto-optimal sets (PSs) and fronts (PFs). Prediction-driven approaches have demonstrated potential in rapidly adapting to these changes. However, many existing methods depend on linear models to forecast the evolving PSs, which may be restrictive. To counteract this limitation, this research presents a novel dynamic multiobjective evolutionary optimization algorithm that incorporates predictions from long short-term memory (LSTM) networks. Initially, in our methodology, the PS for each problem is segmented into multiple clusters, and the centroid of each cluster is identified. These cluster centroids, representing the PSs across various environmental conditions, are then transformed into a series of time series data. The LSTM network models are subsequently trained on this time series data as input samples. Utilizing these refined models, the centroids of the evolving PSs are predicted with improved precision. Moreover, to enhance the performance of the algorithm, an innovative population-generation strategy is also introduced that guarantees a well-converged and diverse starting population. Our proposed algorithm undergoes rigorous testing using benchmark functions, and the outcomes validate its proficiency in tackling DMOPs, showing superior performance compared to existing state-of-the-art algorithms. © 2024, The Authors. All rights reserved.

关键词： Forecasting

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Phase-change metasurfaces for dynamic image display and information encryption

arXiv

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arXiv 2022年

作者： Liu, Tingting Han, Zhou Duan, Junyi Xiao, Shuyuan Institute of Photonic Chips University of Shanghai for Science and Technology Shanghai200093 China Centre for Artificial-Intelligence Nanophotonics School of Optical-Electrical and Computer Engineering University of Shanghai for Science and Technology Shanghai200093 China Institute for Advanced Study Nanchang University Nanchang330031 China Jiangxi Key Laboratory for Microscale Interdisciplinary Study Nanchang University Nanchang330031 China

Optical metasurfaces enable to engineer the electromagnetic space and control light propagation at an unprecedented level, offering a powerful tool to achieve modulation of light over multiple physical dimensions. Here, we demonstrate a Sb2S3 phase-change metasurface platform that allows active manipulation of both amplitude and phase. In particular, we implement dynamic nanoprinting and holographic image display through tuning crystallization levels of this phase-change material. The Sb2S3 nanobricks tailored to function the amplitude, geometric and propagation phase modulation constitute the dynamic meta-atoms in the multiplexed metasurfaces. Using the incident polarizations as decoding keys, the encoded information can be reproduced into a naonprinting grayscale image in the near field and two holographic images in the far field. These images can be switched on and off by taking advantages of the reversible tunability of Sb2S3 nanostructure between amorphous and crystalline states. The proposed phase-change metasurfaces featuring manifold information and multifold encryption promise ultracompact data storage with high capacity and high security, which suggests an exciting direction for modern cryptography and security applications. Copyright © 2022, The Authors. All rights reserved.

关键词： Cryptography

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Improving EFL Students' Reading Skills Using Graph Attention Networks and Intelligence-Based Tasks

Improving EFL Students' Reading Skills Using Graph Attention...

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Integrated Circuits and Communication Systems (ICICACS), IEEE International Conference on

作者： Radha Ranjan Arpita Goswami Benzigar M Julius Irudayasamy K. Lokeswar Reddy M V Rathnamma Department of Law Amity Law School Amity University Patna India Department of Humanities School of Liberal Study Kalinga Institute of Industrial Technology (KIIT) Deemed to be University Bhubaneswar India Department of Arts and Humanities Christ Academy Institute for Advanced Studies Bangalore India Department of English Language and Literature CAAS Dhofar University Salalah Oman Department of Artificial Intelligence and Machine Learning Annamacharya University Rajampet India Department of Computer Science and Engineering KLM College of Engineering for Women Kadapa India

ISBN: (数字)9798331508456

ISBN: (纸本)9798331508463

Reading is an engaging practice that helps language learners understand texts. Develop and prioritize basic skills like reading strategies to improve performance and learn new languages. Reading and reading methods will be defined, distinct reading techniques reviewed, successful reading models established, and essential reading principles investigated. The suggested approach involves preprocessing, feature extraction, and model training. PREP techniques such stop word reduction and Porter stemming address data sparsity. Latent Dirichlet Allocation (LDA) selects features, and Hierarchical Generative Adversarial Network trains models. When compared to BERT and GAN, the recommended model wins. The model's 95.39% accuracy is impressive. This proposed shows that the suggested technique improves reading comprehension and text processing precision. Superior preprocessing, feature selection, and hierarchical GAN-based training make it superior to state-of-the-art methods.

关键词： Training Accuracy Inspection Generative adversarial networks Feature extraction Resource management Proposals Integrated circuit modeling Pupils Text processing

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Three-stage dynamics of nonlinear pulse amplification in an ultrafast mid-infrared fiber amplifier with anomalous dispersion

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Optics Express 2025年第13期33卷 26948-26961页

作者： Weiyi Sun Jiapeng Huang Liming Chen Zhuozhao Luo Wei Lin Zeqing Li Cong Jiang Zhiyuan Huang Xin Jiang Pengfei Wang Yuxin Leng Meng Pang Russell Centre for Advanced Lightwave Science Hangzhou Institute of Optics and Fine Mechanics and Shanghai Institute of Optics and Fine Mechanics Hangzhou 311421 China State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in UltraIntense Laser Science Shanghai Institute of Optics and Fine Mechanics (SIOM) Chinese Academy of Sciences (CAS) Shanghai 201800 China School of Physical Science and Technology Shanghai Tech University Shanghai 200031 China jiapenghuang@*** School of Physics and Optoelectronic Engineering Hangzhou Institute for Advanced Study University of Chinese Academy of Sciences Hangzhou 310024 China Center for Advanced Optoelectronic Functional Material Research Northeast Normal University Changchun 130024 China pengfei.wang@tudublin.ie

Nonlinear pulse amplification in optical fiber, with the capability of breaking the gain-bandwidth limitation, is a key technique for high-energy, ultrafast pulse generation. In the longer wavelength region (including 1.55 μm, 2 μm and 2.8 μm) where the gain fiber has normally strong anomalous dispersion, the nonlinear amplification process over fiber exhibits more complicated dynamics than that of its 1-μm counterpart, and the underlying mechanism of the nonlinear pulse propagation process in high-gain anomalous fiber is still elusive so far. Here, we demonstrate an in-depth study on the nonlinear amplification process in high-gain ultrafast mid-infrared fiber, providing a clear physical understanding on the debate of adiabatic soliton compression. We unveil that under the high-gain condition, the ultrafast pulse launched into the anomalous gain fiber experiences successively three distinct stages, named as the balance between linear and nonlinear chirp, high-order-soliton-like pulse compression and soliton fission due to high-order effects. While a relatively clean ultrafast pulse can be obtained immediately after the high-order-soliton-like compression stage, excessive gain fiber length could hardly enhance further the pulse peak power due to soliton fission. Our findings can provide several critical guidelines for designing high-power ultrafast fiber amplifiers at near- and mid-infrared wavelengths.

关键词： Femtosecond lasers Nonlinear optical fibers Optical amplifiers Optical fibers Pulse compression Ultrafast lasers

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Multi-level Feature Learning for Contrastive Multi-view Clustering

arXiv

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arXiv 2021年

作者： Xu, Jie Tang, Huayi Ren, Yazhou Peng, Liang Zhu, Xiaofeng He, Lifang School of Computer Science and Engineering University of Electronic Science and Technology of China Chengdu611731 China Shenzhen Institute for Advanced Study University of Electronic Science and Technology of China Shenzhen518000 China Department of Computer Science and Engineering Lehigh University PA18015 United States

Multi-view clustering can explore common semantics from multiple views and has attracted increasing attention. However, existing works punish multiple objectives in the same feature space, where they ignore the conflict between learning consistent common semantics and reconstructing inconsistent view-private information. In this paper, we propose a new framework of multi-level feature learning for contrastive multi-view clustering to address the aforementioned issue. Our method learns different levels of features from the raw features, including low-level features, high-level features, and semantic labels/features in a fusion-free manner, so that it can effectively achieve the reconstruction objective and the consistency objectives in different feature spaces. Specifically, the reconstruction objective is conducted on the low-level features. Two consistency objectives based on contrastive learning are conducted on the high-level features and the semantic labels, respectively. They make the high-level features effectively explore the common semantics and the semantic labels achieve the multi-view clustering. As a result, the proposed framework can reduce the adverse influence of view-private information. Extensive experiments on public datasets demonstrate that our method achieves state-of-the-art clustering effectiveness. Copyright © 2021, The Authors. All rights reserved.

关键词： Semantics

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Emergence of 6-particle "hexciton" states in WS2 and MoSe2 monolayers

arXiv

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arXiv 2023年

作者： Choi, J. Li, J. Van Tuan, D. Dery, H. Crooker, Scott A. National High Magnetic Field Laboratory Los AlamosNM87545 United States Advanced Instrumentation Institute Korea Research Institute of Standards and Science Daejeon34113 Korea Republic of Wuhan National High Magnetic Field Center School of Physics Huazhong University of Science and Technology Hubei430074 China Department of Electrical and Computer Engineering University of Rochester RochesterNY14627 United States Department of Physics and Astronomy University of Rochester RochesterNY14627 United States

When doped with a high density of mobile charge carriers, monolayer transition-metal dichalcogenide (TMD) semiconductors can host new types of composite many-particle exciton states that do not exist in conventional semiconductors. Such multi-particle bound states arise when a photoexcited electron-hole pair couples to not just a single Fermi sea that is quantum-mechanically distinguishable (as for the case of conventional charged excitons or trions), but rather couples simultaneously to multiple Fermi seas, each having distinct spin and valley quantum numbers. Composite six-particle "hexciton" states were recently identified in electron-doped WSe2 monolayers, but under suitable conditions they should also form in all other members of the monolayer TMD family. Here we present spectroscopic evidence demonstrating the emergence of many-body hexcitons in charge-tunable WS2 monolayers (at the A-exciton) and MoSe2 monolayers (at the B-exciton). The roles of distinguishability and carrier screening on the stability of hexcitons are discussed. © 2023, CC BY.

关键词： Monolayers

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Robust enhancement of high-harmonic generation from all-dielectric metasurfaces enabled by polarization-insensitive bound states in the continuum

arXiv

引用

arXiv 2022年

作者： Xiao, Shuyuan Qin, Meibao Duan, Junyi Liu, Tingting Institute for Advanced Study Nanchang University Nanchang330031 China Jiangxi Key Laboratory for Microscale Interdisciplinary Study Nanchang University Nanchang330031 China School of Physics and Materials Science Nanchang University Nanchang330031 China Institute of Photonic Chips University of Shanghai for Science and Technology Shanghai200093 China Centre for Artificial-Intelligence Nanophotonics School of Optical-Electrical and Computer Engineering University of Shanghai for Science and Technology Shanghai200093 China

The emerging all-dielectric platform exhibits high-quality (Q) resonances governed by the physics of bound states in the continuum (BIC) that drives highly efficient nonlinear optical processes. Here we demonstrate the robust enhancement of third-(THG) and fifth-harmonic generation (FHG) from all-dielectric metasurfaces composed of four silicon nanodisks. Through the symmetry breaking, the genuine BIC transforms into the high-Q quasi-BIC resonance with tight field confinement for record high THG efficiency of 3.9 × 10−4 W−2 and FHG efficiency of 4.8 × 10−10 W−4 using a moderate pump intensity of 1 GW/cm2. Moreover, the quasi-BIC and the resonantly enhanced harmonics exhibit polarization-insensitive characteristics due to the special C4 arrangement of meta-atoms. Our results suggest the way for smart design of efficient and robust nonlinear nanophotonic devices. Copyright © 2022, The Authors. All rights reserved.

关键词： Harmonic generation

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High-efficiency optical frequency mixing in an all-dielectric metasurface enabled by multiple bound states in the continuum

arXiv

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arXiv 2022年

作者： Liu, Tingting Qin, Meibao Wu, Feng Xiao, Shuyuan Institute of Photonic Chips University of Shanghai for Science and Technology Shanghai200093 China Centre for Artificial-Intelligence Nanophotonics School of Optical-Electrical and Computer Engineering University of Shanghai for Science and Technology Shanghai200093 China School of Physics and Materials Science Nanchang University Nanchang330031 China School of Optoelectronic Engineering Guangdong Polytechnic Normal University Guangzhou510665 China Institute for Advanced Study Nanchang University Nanchang330031 China Jiangxi Key Laboratory for Microscale Interdisciplinary Study Nanchang University Nanchang330031 China

We present nonlinear optical four-wave mixing in a silicon nanodisk dimer metasurface. Under the oblique incident plane waves, the designed metasurface exhibits a multi-resonant feature with simultaneous excitations of three quasi-bound states in the continuum (BIC). Through employing these quasi-BICs with maximizing electric field energy at the input bump wavelengths, significant enhancement of third-order nonlinear processes including third-harmonic generation, degenerate and non-degenerate four-wave mixing are demonstrated, giving rise to ten new frequencies in the visible wavelengths. This work may lead to a new frontier of ultracompact optical mixer for applications in optical circuitry, ultrasensitive sensing, and quantum nanophotonics. Copyright © 2022, The Authors. All rights reserved.

关键词： Four wave mixing

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Polarization-controlled dynamically switchable high-harmonic generation from all-dielectric metasurfaces governed by dual bound states in the continuum

arXiv

引用

arXiv 2022年

作者： Xiao, Shuyuan Qin, Meibao Duan, Junyi Wu, Feng Liu, Tingting Institute for Advanced Study Nanchang University Nanchang330031 China Jiangxi Key Laboratory for Microscale Interdisciplinary Study Nanchang University Nanchang330031 China School of Physics and Materials Science Nanchang University Nanchang330031 China School of Optoelectronic Engineering Guangdong Polytechnic Normal University Guangzhou510665 China Institute of Photonic Chips University of Shanghai for Science and Technology Shanghai200093 China Centre for Artificial-Intelligence Nanophotonics School of Optical-Electrical and Computer Engineering University of Shanghai for Science and Technology Shanghai200093 China

Tailoring optical nonlinear effects (e.g. harmonic generation, sum-frequency mixing, etc.) in the recently emerging all-dielectric platform is important for both the fundamental science and industrial development of high-efficiency, ultrafast, and miniaturized photonic devices. In this work, we propose a novel paradigm for dynamically switchable high-harmonic generation in Silicon nanodimer metasurfaces by exploiting polarization-controlled dual bound states in the continuum (BIC). Owing to the high-quality factor of BIC resonances, efficient harmonic signals including the third-harmonic generation and fifth-harmonic generation from a direct process as well as a cascaded process by degenerate four-wave mixing are obtained. Moreover, the BICs and their resonantly enhanced harmonics can be switched on or off with high selectivity respect to the fundamental pump polarization. Compared with previous reports, our work provide a simple but effective tuning strategy by fully exploring the structural symmetry and polarization degree of freedom rather than resorting to additional external stimuli, which would have great advantages in smart designing tunable and switchable nonlinear light source for chip-scale applications. Copyright © 2022, The Authors. All rights reserved.

关键词： Harmonic generation

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EndoFinder: Online Image Retrieval for Explainable Colorectal Polyp Diagnosis

arXiv

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arXiv 2024年

作者： Yang, Ruijie Zhu, Yan Fu, Peiyao Zhang, Yizhe Wang, Zhihua Li, Quanlin Zhou, Pinghong Yang, Xian Wang, Shuo Digital Medical Research Center School of Basic Medical Sciences Fudan University Shanghai China Shanghai Key Laboratory of MICCAI Shanghai China Shanghai Institute for Advanced Study of Zhejiang University Shanghai China Endoscopy Center Endoscopy Research Institute Zhongshan Hospital Fudan University Shanghai China Shanghai Collaborative Innovation Center of Endoscopy Shanghai China School of Computer Science and Engineering Nanjing University of Science and Technology Jiangsu Nanjing China Alliance Manchester Business School The University of Manchester Manchester United Kingdom

Determining the necessity of resecting malignant polyps during colonoscopy screen is crucial for patient outcomes, yet challenging due to the time-consuming and costly nature of histopathology examination. While deep learning-based classification models have shown promise in achieving optical biopsy with endoscopic images, they often suffer from a lack of explainability. To overcome this limitation, we introduce EndoFinder, a content-based image retrieval framework to find the'digital twin' polyp in the reference database given a newly detected polyp. The clinical semantics of the new polyp can be inferred referring to the matched ones. EndoFinder pioneers a polyp-aware image encoder that is pre-trained on a large polyp dataset in a self-supervised way, merging masked image modeling with contrastive learning. This results in a generic embedding space ready for different downstream clinical tasks based on image retrieval. We validate the framework on polyp re-identification and optical biopsy tasks, with extensive experiments demonstrating that EndoFinder not only achieves explainable diagnostics but also matches the performance of supervised classification models. EndoFinder's reliance on image retrieval has the potential to support diverse downstream decision-making tasks during real-time colonoscopy procedures. © 2024, CC BY.

关键词： Semantics

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