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Precision flatness measurement based on orbital angular momentum

Chinese Physics B 2025年第05期 418-426页

作者：韩菲菲王志琬王乐赵生妹 Institute of Signal Processing and Transmission Nanjing University of Posts and Telecommunications Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of Education National Laboratory of Solid State Microstructures Nanjing University

We propose a method to measure the flatness of an object with a petal-like pattern generated by the interference of the measured orbital angular momentum（OAM） beam and the reference OAM beam which carries the opposite OAM *** calculating the difference between the petal rotation angle without/with the object,the thickness information of the object,and then the flatness information,can be ***,the direction of the object's flatness can be determined by the petal's clockwise/counterclockwise *** theoretically analyze the relationship between the object's thickness and petal rotation angle,and verify the proposed method by *** experimental results show that the proposed method is a high precision flatness measurement and can obtain the convex/concave property of the *** the 1.02 mm glass sample,the mean deviation of the flatness is 1.357×10-8and the variance is 0.242×*** the 0.50 mm glass sample,the mean deviation of the flatness is 1.931 ×10-8and the variance is 2.405×*** different topological charges are adopted for the 2.00 mm glass sample,and their flatness deviations are 0.239 ×10-8（■=1）and 0.246×10-8（■=2）,where their variances are 0.799×10-18（■=1） and 0.775×10-18（■=2）,*** is shown that the flatness measured by the proposed method is the same for the same sample when different topological charges are *** results indicate that the proposed method may provide a high flatness measurement,and will be a promising way to measure the flatness.

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One-decoy state reference-frame-independent quantum key distribution

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Chinese Physics B 2020年第7期29卷 246-250页

作者： Xiang Li Hua-Wei Yuan Chun-Mei Zhang Qin Wang Institute of Quantum Information and Technology Nanjing University of Posts and TelecommunicationsNanjing 210003China Broadband Wireless Communication and Sensor Network Technology Key Laboratory of Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing 210003China

Reference-frame-independent quantum key distribution(RFI-QKD)has been proven to be very useful and practical under realistic ***,we present a scheme for one-decoy state RFI-QKD based on the work of Rusca et al.[***.112,171104(2018)],and carry out investigation on its performance under realistic experimental *** simulation results show that the one-decoy state RFI-QKD can achieve comparable performance in terms of secret key rate and transmission distance as the two-decoy state correspondence under practical experimental *** contrast,it does not need to prepare the vacuum state in the former case,substantially reducing the experimental complexity and random number ***,our present proposal seems very promising in practical implementations of RFI-QKD.

关键词： quantum key distribution RFI-QKD one decoy state

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Heart Rate Detection with the Off-the-Shelf Camera: Static to Non-Static 5

Heart Rate Detection with the Off-the-Shelf Camera: Static t...

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5th IEEE International Conference on Signal and Image Processing, ICSIP 2020

作者： Chen, Rui Chen, Jianxin Cheng, LiMing Huang, XiangJun Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Nanjing China

ISBN: (纸本)9781728168968

Imaging photo-plethysmography (IPPG) technique has been proven to detect heart rate (HR) with a camera. Currently it might be used in a rigid scenario, such as the static subject, the short measurement distance and good illumination. In this paper, we try to relax these constraints by extending the measurement distance and applying it to the non-static subject with IPPG technique using the off-the-shelf camera. To achieve it, the landmark detection method is used to locate the facial region of interest (ROI) for the subject during movements. On this ROI, R/G/B channel signals are extracted with the spatial average of pixels. Then we use a skin appearance model (CHROME) to remove the noise, and HR is estimated from the output of the CHROME through the power spectrum. Experimental results showed that our method works effectively in both static and non-static scenarios. In static scenario, the measurement distance can extend to 4 meters, while the accuracy can reach 86% compared with the results from a finger detection equipment. In non-static scenario, our method achieve better results than previous studies. © 2020 IEEE.

关键词： Cameras

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Research on Functional Test of Mobile APP Based on Robot 5

Research on Functional Test of Mobile APP Based on Robot

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5th IEEE International Conference on Signal and Image Processing, ICSIP 2020

作者： Pan, Zhaolai Chen, Jianxin Yao, Ling Chen, ZhuAn Nanjing University of Posts and Telecommunications Ministry of Education Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing China

ISBN: (纸本)9781728168968

With the rapid popularization of smartphones, various applications (Application: APP) have come into being. Therefore, automated testing of mobile applications is particularly important. At present, the automated testing on the market is often completed through test frameworks. However, when using the test framework we need to consider the compatibility of the mobile platform system. What's worse, accessing multiple apps at the same time has a bad impact on accuracy. In view of these problems, a robot-based automated test system for mobile applications is proposed. Firstly, a wireless projection technology is utilized to project the screen of a mobile device onto a computer screen. Then, the optical character recognition (OCR) algorithm and the normalized correlation matching algorithm are used to position the coordinates of the elements. Finally, the robot performs a click operation under control. The experimental results show that the system can achieve cross-platform testing, including automatically testing Chinese software or English software on Android and iOS platforms, and also has high accuracy and robustness. © 2020 IEEE.

关键词： Software testing

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Pilot Assignment Based on Graph Coloring with Sum-Rate Maximization in Cell-Free Massive MIMO

Pilot Assignment Based on Graph Coloring with Sum-Rate Maxim...

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International Conference on Computer and communications (ICCC)

作者： Rongheng Chen Hong Wang Rongfang Song Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing China

ISBN: (纸本)9781665409513

To mitigate the severe effect of pilot contamination, a novel graph coloring (NGC) based algorithm is applied to pilot assignment in cell-free massive multiple-input multiple-output (MIMO) systems. Specifically, firstly, the potential pilot contamination intensity among users is calculated by utilizing the large-scale fading between users and access points (APs). Then, the contamination threshold is set to perform the sparsification and an interference graph describing the user interference relationship is constructed. Finally, the proposed algorithm is used to implement pilot assignment in the interference graph. In addition, an iterative grid search (IGS) approach is adopted to update the threshold to ensure that the system downlink sum-rate is maximized. The numerical results reveal that the proposed NGC pilot assignment algorithm with optimized thresholds can remarkably improve the system performance compared with previous pilot assignment schemes.

关键词： Fading channels System performance Simulation Interference Massive MIMO Downlink MIMO

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Age of Information Minimization in Intelligent Reflecting Surface-Aided Covert communications

Age of Information Minimization in Intelligent Reflecting Su...

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2022 IEEE GLOBECOM Workshops, GC Wkshps 2022

作者： Wang, Chao Li, Zan Zhao, Yue Ng, Derrick Wing Kwan Al-Dhahir, Naofal Xidian University State Key Laboratory of Integrated Service Network Xi'an710071 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing210003 China Southeast University National Mobile Communications Research Laboratory Nanjing210096 China University of New South Wales School of Electrical Engineering and Telecommunications Sydney2052 Australia The University of Texas at Dallas Department of Electrical and Computer Engineering RichardsonTX75080 United States

ISBN: (纸本)9781665459754

In this work, we investigate the covert information freshness in intelligent reflecting surface (IRS)-aided multi antenna communications, where a public full-duplex user (Alice) and a private full-duplex user (Bob) exchange information in the presence of a watchful warden (Willie). Specifically, the covert transmission from Bob to Alice is shielded from Willie under the mask of Alice's undisguised signal transmission. To minimize the covert information age, we exploit the channel statistics to jointly design the active beamforming at Alice and Bob, the passive beamforming at the IRS, and the blocklength of the confidential data packet under the constraints of the maximum tolerable age of information (AoI) at Bob and communication covertness. Although the considered joint optimization problem is nonconvex, we employ the successive convex approximation to design an iterative algorithm to obtain an efficient suboptimal solution. Numerical results demonstrate the superiority of our proposed joint optimization algorithm and further show that the enhanced covert channel quality can reduce the required blocklength to improve information freshness. © 2022 IEEE.

关键词： Beamforming

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Proposal of a free-space-to-chip pipeline for transporting single atoms

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Physical Review A 2023年第3期108卷 033108-033108页

作者： Aiping Liu Jiawei Liu Zhanfei Kang Guang-Jie Chen Xin-Biao Xu Xifeng Ren Guang-Can Guo Qin Wang Chang-Ling Zou Institute of Quantum Information and Technology Nanjing University of Posts and Telecommunications Nanjing 210003 China Broadband Wireless Communication and Sensor Network Technology Key Lab of Ministry of Education Nanjing University of Posts and Telecommunications Nanjing 210003 China CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei 230026 China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei 230026 China

A free-space-to-chip pipeline is proposed for the efficient transportation of single atoms from a magneto-optical trap to an on-chip evanescent-field trap. Due to the reflection of the dipole laser on the chip surface, the conventional conveyor-belt approach can transport only atoms in close proximity to the chip surface, with a distance of about one wavelength. This limitation hinders the efficient interaction between the atom and the on-chip waveguide devices. Here, a two-layer photonic chip architecture is proposed to realize a free-space-to-chip atom pipeline. By employing a diffraction beam of the integrated grating with an incident angle of the Brewster angle, the reflection of the dipole laser is suppressed, allowing the atoms to be brought to the chip surface with a distance of only 100nm. The pipeline is verified numerically and provides a reliable atom source for a hybrid photonic-atom chip.

关键词： Atom & ion trapping & guiding Integrated optics Interference & diffraction of light Light propagation, transmission & absorption Nanophotonics Polarization of light Atoms Trapped atoms Two-level models

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A Virtual and Non-contact Bounce System Based on Ultrasonic Haptic technology

A Virtual and Non-contact Bounce System Based on Ultrasonic ...

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International wireless communications and Mobile Computing Conference, IWCMC

作者： Yanan Chen Gaolong Jiang Jianxin Chen Shouxiang Ni Mingkai Chen Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications

Haptics has become an important research direction at the present stage. It is an inevitable trend to integrate haptic feedback into human-computer interaction technology in the future. However, traditional contact haptic feedback technology has disadvantages such as fixed equipment and limited space. In order to overcome this difficulty, this paper mainly studies the non-contact haptic feedback, and proposes a virtual bounce system based on ultrasonic haptic. First of all, we analyze the principle of the main modules of the system to provide a theoretical basis for the system design. Secondly, in the design, we combine tactile stimuli with visual stimuli to enhance the visualization and comfort of users during operation. Then, we analyze the performance of the system through experiment. The results show that the virtual bounce system proposed in this paper can free users from the shackles of devices, improve the interaction comfort and immersive experience of users.

关键词： wireless communication Performance evaluation Visualization Immersive experience Market research Acoustics User experience

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Multi-Access Edge Computing using Mode Division Multiple Access

Multi-Access Edge Computing using Mode Division Multiple Acc...

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International Conference on wireless communications and Signal Processing (WCSP)

作者： Lei Wang Haizhou Wang Xue Jiang Jingwu Cui Baoyu Zheng Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Ministry of Education Nanjing China School of Internet of Things Nanjing University of Posts and Telecommunications Nanjing China

ISBN: (纸本)9781665450867

In order to meet the demand for bigger data and lower time of processing data in future industry and daily life, the paper proposes a scheme combining multi-access edge computing (MEC) and mode division multiple access (MDMA). To greatly reduce the MEC system transmission and data processing time of a scenario where multiple devices offload the large amount of data onto the MEC server within the coverage area of base station, modes are used as new communication resources with frequency to form resources blocks which will be allocated. Because the model of MEC system using MDMA contains continuous and boolean variables and the exclusive constraints about using resources blocks, the paper proposes an algorithm combining modified differential evolution (DE), tournament selection (TS) and logical operation, which has a great performance.

关键词： wireless communication Performance evaluation Time-frequency analysis Multi-access edge computing Simulation Signal processing algorithms Signal processing

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Di-defects synergy boost electrocatalysis hydrogen evolution over two-dimensional heterojunctions

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Nano Research 2022年第1期15卷 677-684页

作者： Yan Cui Xiaoyu Guo Jian Zhang Xing’ao Li Xinbao Zhu Wei Huang Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing 210003China New Energy Technology Engineering Lab of Jiangsu Province School of ScienceNanjing University of Posts&Telecommunications(NUPT)Nanjing 210023China Key Laboratory for Organic Electronics and Information Displays&Institute of Advanced Materials(LAM) Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)Nanjing University of Posts&Telecommunications(NUPT)Nanjing 210023China College of Chemical Engineering Nanjing Forestry UniversityNanjing 210037China Shaanxi Institute of Flexible Electronics(SIFE) Northwestern Polytechnical University(NPU)}127 West Youyi RoadXian 710072China

Electronic modulation on the inert basal plane of transition-metal dichalcogenides(TMDs)through vacancy defect excitation,although extremely challenging,is urgent for understanding the factors that impact the hydrogen evolution reaction(HER)catalytic ***,ultrathin WS2 nanosheets with precise quantitative single atomic S-vacancy on the inert basal plane were flexible prepared through hydrogen peroxide etching *** as-synthesized single atomic S-vacancy defect WS2(SVD-WS2)nanoflake with the activated basal plane exhibited an impressive overpotential of 137 mV at a current density of 10 mA·cm^(-2) and a Tafel slope of 53.9 mV dec^(-1).Furthermore,anchoring on the defect graphene matrix,the assembled two-dimensional(2D)stacking heterojunction exhibits further enhanced HER catalytic activity(an overpotential of 108 mV vs.10 mA·cm^(-2) and a Tafel slope of 48.3 mV·dec^(-1))and stability(〜10%decline after 9,000 cycles),which attributed to the electronic structure modulation from the synergetic interactions between SVD-WS_(2) and defect *** finding provides a smart defects introduce strategy to trigger high-efficiency hydrogen evolution over WS_(2) nanosheets and a general 2D heterojunctions fabricated inspiration based on strong interaction interface.

关键词： S-vacancies defect graphene hydrogen evolution reaction heterojunctions

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