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A Rapid Adaptation Approach for Dynamic Air‑Writing Recognition Using Wearable Wristbands with Self‑Supervised Contrastive Learning

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Nano-Micro Letters 2025年第2期17卷 417-431页

作者： Yunjian Guo Kunpeng Li Wei Yue Nam‑Young Kim Yang Li Guozhen Shen Jong‑Chul Lee Department of Electronic Convergence engineering Kwangwoon UniversitySeoul 01897South Korea Radio Frequency Integrated Circuit(RFIC)Bio Centre Kwangwoon UniversitySeoul 01897South Korea Department of Electronic engineering Kwangwoon UniversitySeoul 01897South Korea School of Microelectronics Shandong UniversityJinan 250101People’s Republic of China State Key Laboratory of Integrated Chips and Systems Fudan UniversityShanghai 200433People’s Republic of China School of Integrated Circuits and electronics Beijing Institute of TechnologyBeijing 100081People’s Republic of China

Wearable wristband systems leverage deep learning to revolutionize hand gesture recognition in daily *** existing approaches that often focus on static gestures and require extensive labeled data,the proposed wearable wristband with selfsupervised contrastive learning excels at dynamic motion tracking and adapts rapidly across multiple *** features a four-channel sensing array composed of an ionic hydrogel with hierarchical microcone structures and ultrathin flexible electrodes,resulting in high-sensitivity capacitance *** wireless transmission from a Wi-Fi module,the proposed algorithm learns latent features from the unlabeled signals of random wrist ***,only few-shot labeled data are sufficient for fine-tuning the model,enabling rapid adaptation to various *** system achieves a high accuracy of 94.9%in different scenarios,including the prediction of eight-direction commands,and air-writing of all numbers and *** proposed method facilitates smooth transitions between multiple tasks without the need for modifying the structure or undergoing extensive task-specific *** utility has been further extended to enhance human–machine interaction over digital platforms,such as game controls,calculators,and three-language login systems,offering users a natural and intuitive way of communication.

关键词： Wearable wristband Self-supervised contrastive learning Dynamic gesture Air-writing Human-machine interaction

Application of uniform DFT filter bank in radar jamming system

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Journal of Systems engineering and electronics 2006年第3期17卷 527-530页

作者： Dai Le Gao Meiguo dept. of electronics engineering of the beijing institute of technology Beijing 100081 P. R. China

The principle of uniform DFT filter bank is presented. Exploiting poly-phase structure, radar jamming system samples the intercepted wideband radar signals through analysis filter bank by different channels and linearly modulates the intercepted radar signal according to the theory of signal and system, then synthesizes the jamming signal through the synthesis filter hank. The method merely requires lower sample frequency, reduces the computational complexity and the data quantity to be processed. The un-ideal filter＇s influence to the result of signals processing is analyzed by simulating the match filter in radar jamming system.

关键词： repeater jamming high resolution radar filter bank poly-phase structure FDT

Gas film performance of double-row orifices of aerostatic guideways

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Journal of Harbin institute of technology(New Series) 2012年第1期19卷 50-54页

作者：陈东菊范晋伟张飞虎 College of Mechanical engineering & Applied electronics technology Beijing University of Technology dept. of Mechanical engineering Harbin Institute of Technology

In order to analyze the performance of aerostatic guidways,the stiffness calculation equation of the aerostatic guideway with two-row orifice has been derived by gas lubrication theory. For the complex structure of the motion guideway and unloading guideway,the frequency of the whole slides in machining direction with gas thickness has been derived. Wavelet transform as a means to process the measured signal of workpiece surface, the frequency characteristics of gas fluctuation of aerostatic guideways has been extracted out from the measured signal,and the errors of the guideway system have been identified according to the power spectral density (PSD) ,and this provide a basis for the identification of machine tool error.

关键词： aerostatic guidways gas fluctuations wavelet transform PSD error identification

Intracavity optical parametric oscillator at 1.57-μm wavelength pumped by passive Q-switched Nd:GdVO_4 laser

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Chinese Optics Letters 2008年第2期6卷 127-129页

作者：高明伟高春清唐坤林志峰张秀勇 Department of Opto-electronics engineering beijing institute of technology

A high-repetition-rate eye-safe optical parametric oscillator （OPO）, using a non-critically phase-matched KTP crystal intracavity pumped by a passively Q-switched Nd：GdVO4/Cr^4＋：YAG laser, is experimentally demonstrated. The conversion efficiency for the average power is 7% from pump diode input to OPO signal output and the slope efficiency is up to 10.3%. With an incident pump power of 7,3 W, the compact intracavity OPO （IOPO） cavity, operating at 15 kHz, produces an average power of 0.57 W at 1570 nm with a pulse width as short as 6 ns. The peak power at 1570 nm is higher than 6.3 kW.

关键词： Conversion efficiency Q switched lasers Solid state lasers

Improvement of four-wave mixing-based wavelength conversion efficiency in dispersion shifted fiber by 40-GHz clock pumping

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Chinese Optics Letters 2008年第4期6卷 291-293页

作者：杨爱英孙雨南 Department of Opto-electronics engineering beijing institute of technology Beijing 100081

40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing （FWM）-based wavelength conversion in a 26.5-km dispersion shifted fiber （DSF） is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave （CW） light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm.

关键词： Conversion efficiency Four wave mixing Optical frequency conversion Optical pumping

Generation and application of the twisted beam with orbital angular momentum

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Chinese Optics Letters 2007年第2期5卷 89-92页

作者：高明伟高春清林志锋 Department of Opto-electronics engineering Beijing Institute of TechnologyBeijing 100081

The twisted Laguerre-Gaussian beam was generated by transforming of Hermite-Gaussian beams through an optical system consisting of three rotated cylindrical lenses. The intensity distribution and phase structure of the twisted hollow beam were theoretically analyzed by using Collins diffraction integral. By utilizing the method of mode decomposition, the theory of transformation was analyzed. In the experiment, micro particles were trapped and rotated by this twisted beam.

关键词： Angular momentum Optical systems Phase structure

An adaptive 3D reconstruction method for asymmetric dual-angle multispectral stereo imaging system on UAV platform

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Science China(Information Sciences) 2024年第8期67卷 285-299页

作者： Chen WANG Xian LI Yanfeng GU Zixu WANG School of electronics and Information engineering Harbin Institute of Technology beijing institute of Control and Electronic technology

A multispectral imaging system often cannot capture 3D spatial information owing to hardware limitations, which diminishes the effectiveness across various domains. To address this problem, we have developed a multispectral stereo imaging system along with an adaptive 3D reconstruction algorithm. Unlike existing unmanned aerial vehicle stereo imaging systems, our multispectral stereo imaging system uses two multispectral cameras with asymmetric spectral bands positioned at different angles. This design enables the acquisition of a higher number of bands and lateral spatial information while maintaining a lightweight structure. This system introduces challenges such as large geometric distortions and intensity differences between multiple bands. To accurately recover 3D spatial information, we propose an adaptive 3D reconstruction method. This method employs a position and orientation system-assisted projection transformation and a normalized threshold adjustment strategy. Finally, mutual information is used to reconstruct the multispectral images densely, effectively addressing nonlinear differences and generating a comprehensive multispectral point cloud. Our stereo system was used for two real data collections in different regions, and the efficacy of the proposed 3D reconstruction method was validated by comparing it with existing methods and commercial software.

关键词： multispectral images 3D reconstruction stereo imaging system unmanned aerial vehicle feature extraction

同方期刊数据库

Transformation method and wave control

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Acta Mechanica Sinica 2010年第6期26卷 889-898页

作者： Zheng Chang Jin Hu Geng-Kai Hu School of Aerospace engineering Beijing Institute of Technology 100081 BeijingChina School of Information and electronics Beijing Institute of Technology100081 BeijingChina

Transformation method provides an efficient way to control wave propagation by *** transformed relations for field and material during a transformation are essential to fulfill this *** propose a systematic method to derive the transformed relations for a general physic process,the constraint conditions are obtained by considering geometrical and physical constraint during a mapping. The proposed method is applied to Navier＇s equation for elastodynamics,Helmholtz＇s equation for acoustic wave and Maxwell＇s equation for electromagnetic wave,the corresponding transformed relations are derived,which can be used in the framework of transformation method for wave *** show that contrary to electromagnetic wave,the transformed relations are not uniquely determined for elastic wave and acoustic wave,so we have a freedom to choose them *** the obtained transformed relations,we also provide some examples for device design,a concentrator for elastic wave,devices for illusion acoustic and illusion optics are conceived and validated by numerical simulations.

关键词： Wave control Elastic wave Acoustic wave Electromagnetic wave Local affine transformation

An improved spectral performance of SPWM inverter based on the time-sequence of chaos

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Journal of Harbin institute of technology(New Series) 2007年第1期14卷 59-63页

作者：李冠林陈希有刘洪臣杨伟 dept. of Electrical engineering Harbin Institute of Technology dept. of Electrical and electronics engineering Dalian University of Technology

A novel approach for improving the spectral performance of sinusoidal Pulse Width Modulation (SPWM) inverter is presented. By varying the carrier frequency according to chaotic time-sequence, the discrete spectrum of the output voltage is transformed into the continuous spectrum, which could reduce the acoustic noise concentrated at specific tones in an inverter-driven electric machine. Fourier analysis shows that the harmonic at the fixed frequency has been restrained effectively and the distribution of the spectrum is in a wider range. Besides, a novel variable is introduced for the evaluation of the output voltage spectrum in SPWM inverter. Simulations and experiments with DSP confirm the advantages of the novel approach. Experimental results show the annoying acoustic noise has been translated into some enjoyable sound like a fall or water flowing when this novel method is applied.

关键词： inverter SPWM harmonic time-sequence chaos