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Pulse Doppler Radar with Antenna Arrays Estimating Angular Velocity

IEICE Transactions on Communications 2025年第5期E108.B卷 693-700页

作者： Yamaoka, Tomoya Oshima, Tadashi Information Technology Research and Development Center Mitsubishi Electric Corporation Kamakura-shi247-8501 Japan

Radar provides information on target distance, direction, and velocity, but not directly on angular velocity. We study signal processing for estimating angular velocity directly by radar. First, we describe the signal model. In addition, the Cramer-Rao lower bound (CRLB) is derived to show the feasibility of angular velocity estimation. Furthermore, a method for estimating angular velocity is proposed in which the angular velocity is obtained by capturing the variations in the angular spectrum after noise reduction for signals represented in two dimensions: array and slow time. Specifically, we focus the signal with a frequency transform in the slow-time direction, insert zeros outside the focused target, and perform an inverse frequency transformation to obtain the signal with less noise. In the array direction, zeros are inserted on both sides, frequency transform is carried out, and interpolation is performed to capture the time variation to the azimuth angle. The angular velocity is obtained by evaluating the captured angular change using the least-squares method. Evaluation results show that angular velocity estimation performance improves with more antennas and higher signal-to-noise power ratio. When inserting zeroes, the appropriate length of target extraction can mitigate the adverse effects of noise and the Gibbs phenomenon. However, the angular velocity estimation performance of the proposed method deviates from that of the CRLB and requires improvement. Copyright © 2025 The Institute of electronics, information and Communication Engineers.

关键词： Least squares approximations

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Evaluating Semantic Segmentation of Tuberculosis Bacilli in Bright Field Microscopy Using Different Color Spaces Components and Mosaic Images 9th

Evaluating Semantic Segmentation of Tuberculosis Bacilli in ...

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9th Latin American Congress on Biomedical Engineering, CLAIB 2022 and 28th Brazilian Congress on Biomedical Engineering, CBEB 2022

作者： Serrão, M.K. Saldanha, I.M. Costa, M.G.F. Costa Filho, C.F.F. Federal University of Amazonas/ Center for Research and Development in Electronic and Information Technology – CETELI Manaus Brazil

ISBN: (纸本)9783031494031

Tuberculosis is one of the infectious diseases that causes the most victims in the world. The early diagnosis of the disease is fundamental for the treatment to be carried out quickly, saving lives and decreasing the number of infected people. The tuberculosis diagnosis is a time-consuming process that involves the analysis of up to 100 fields of conventional microscopy, which causes fatigue for the technician involved in the process. In order to assist the technician in counting bacilli in tuberculosis bright field microscopy examinations, automatic methods using deep neural networks are proposed. In this work, we evaluate the use of a semantic segmentation network for bacilli detection, using as input several color components from the RGB, HSV, YCbCr, and Lab spaces. The model that presented the best performance uses only the components of RGB color space as input to the network, with values of accuracy, precision, sensitivity, specificity, and f1-score above 99%. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

关键词： Semantic Segmentation

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Near-field wideband channel estimation for extremely large-scale MIMO

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Science China(information Sciences) 2023年第7期66卷 283-296页

作者： Mingyao CUI Linglong DAI Department of Electronic Engineering Tsinghua University Beijing National Research Center for Information Science and Technology(BNRist)

Extremely large-scale multiple-input-multiple-output(XL-MIMO) at millimeter-wave(mm Wave)and terahertz(THz) bands plays an important role in supporting extreme high beamforming gain as well as ultra-wideband spectrum resources. Unfortunately, accurate wideband XL-MIMO channel estimation suffers from a new challenge called the near-field beam split effect. Prior studies either neglect the accurate nearfield channel model or fail to exploit the beam split effect, resulting in poor channel estimation accuracy for wideband XL-MIMO. To tackle this problem, this paper proposes a bilinear pattern detection(BPD)-based approach to accurately recover the wideband XL-MIMO channel. Specifically, by analyzing the characteristics of near-field wideband channels, we first reveal the bilinear pattern of the near-field beam split effect, which implies that the sparse support set of near-field channels in both the angle and the distance domains can be regarded as a linear function against frequency. Then, inspired by the classical simultaneously orthogonal matching pursuit technique, we use the bilinear pattern to estimate the angle-of-arrival(Ao A) and distance parameters of each near-field path component at all frequencies. In this way, the entire wideband XL-MIMO channel can be recovered by compressed sensing algorithms. Moreover, we provide the computational complexity of the proposed algorithm compared with existing algorithms. Finally, simulation results demonstrate that our scheme can achieve the accurate estimation of the near-field wideband XL-MIMO channel in the presence of near-field beam split effect.

关键词： XL-MIMO wideband near-field beam split channel estimation

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High-speed optoelectronic devices

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Science China(information Sciences) 2023年第5期66卷 5-27页

作者： Yi LUO Changzheng SUN Bing XIONG Jian WANG Zhibiao HAO Yanjun HAN Hongtao LI Lai WANG Beijing National Research Center for Information Science and Technology (BNRist) Department of Electronic Engineering Tsinghua University

High-speed optoelectronic devices are key components of modern fiber communication systems,and the backbone of information technology. In this paper, we present our work on high-speed devices over the past decades, including high-performance semiconductor lasers and integrated light sources, wideband electrooptic modulators, high saturation power photodetectors, and their applications in both fiber communications and microwave photonics. Gain-coupled distributed feedback(DFB) lasers were fabricated with high singlemode yield. Electroabsorption modulated lasers(EMLs) were demonstrated based on identical epitaxial layer integration scheme, including single channel 40 Gb/s EMLs, and 4 × 25 and 4 × 56 Gb/s EML arrays. Both In P and thin-film lithium niobate based low half-wave voltage electro-optic modulators with modulation bandwidth over 40 GHz were demonstrated. Back-illuminated modified uni-traveling-carrier photodetectors(MUTC-PDs) with high saturation power and bandwidth exceeding 100 GHz were developed. Applications of high-speed optoelectronic devices in fiber-optic links and sub-THz wave generation are presented.

关键词： optoelectronic devices semiconductor lasers optical modulators photodetectors integrated photonic circuits

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Focusing Ability Enhancement in Broadside Direction of Array:From UCA to UCCA

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Tsinghua Science and technology 2024年第5期29卷 1593-1603页

作者： Zidong Wu Linglong Dai Department of Electronic Engineering Tsinghua Universityand also with Beijing National Research Center for Information Science and Technology(BNRist)Beijing 100084China

To meet the ever-increasing demand for the data rates of wireless communications,extremely large-scale antenna array(ELAA)has emerged as one of the candidate technologies for future 6G *** significantly increased number of antennas in ELAA gives rise to near-field communications,necessitating tailored beamforming techniques within the near-field regions to accommodate the spherical-wave propagation *** various array geometries of ELAA,uniform circular array(UCA)has gained much attention for its distinct capability of maintaining uniform beam pattern across different azimuth ***,existing analysis of near-field UCA beamforming indicates that the near-field region severely declines in the broadside of UCA,where the system fails to benefit from near-field *** tackle this problem,the near-field beamforming technique of uniform concentric circular arrays(UCCAs)is investigated in this paper,which has the potential to enlarge the near-field region in the broadside ***,the analysis of beamforming gain in the 3D space with UCA and UCCA is ***,the distinct beamforming characteristics that set UCCA apart from UCA are delineated,revealing the superiority of UCCA in extending the near-field region in broadside at the cost of slightly reduced near-field region in the *** results are provided to verify the effectiveness of the theoretical analysis of beamforming gain with UCCA and the enhanced focusing ability of UCCA in the broadside direction.

关键词： extremely large-scale antenna array(ELAA) uniform concentric circular array(UCCA) near-field communications

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Resource Allocation for Channel Estimation in Reconfigurable Intelligent Surface-Aided Multi-Cell Networks

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Journal of Communications and information Networks 2024年第1期9卷 64-79页

作者： Yining Xu Sheng Zhou Department of Electronic Engineering Beijing National Research Center for Information Science and TechnologyTsinghua UniversityBeijing 100084China

Reconfigurable intelligent surface(RIS)is a promising solution to deal with the blockage-sensitivity of millimeter wave band and reduce the high energy consumption caused by network densification. However, deploying large scale RISs may not bring expected performance gain due to significant channel estimation overhead and non-negligible reflected *** this paper,we derive the analytical expressions of the coverage probability, area spectrum efficiency(ASE)and energy efficiency (EE)of a downlink RIS-aided multi-cell *** order to optimize the network performance, we investigate the conditions for the optimal number of training symbols of each antenna-to-antenna and antenna-to-element path (referred to as the optimal unit training overhead) in channel *** study shows that:1)RIS deployment is not“the more, the better”, only when blockage objects are dense should one deploy more RISs;2) the coverage probability is maximized when the unit training overhead is designed as large as possible;3)however,the ASE-and-EE-optimal unit training overhead exists. It is a monotonically increasing function of the frame length and a monotonically decreasing function of the average signal-to-noise-ratio (in the high signal-to-noise-ratio region). Additionally,the optimal unit training overhead is smaller when communication nodes deploy particularly few or many antennas.

关键词： reconfigurable intelligent surface multi-cell network directional transmissions channel estimation resource allocation stochastic geometry

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Dual-assisted high-precision tracking technique for wideband multiplexed signals in new generation GNSS

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Satellite Navigation 2024年第1期5卷 52-73页

作者： Yunhan Qi Zheng Yao Mingquan Lu Department of Electronic Engineering Tsinghua UniversityBeijing100084China Beijing National Research Center for Information Science and Technology Beijing100084China

With the evolution of Global Navigation Satellite System(GNSS),new generation GNSS signals have adopted the dual-frequency multiplexing modulation techniques,which jointly modulate multiple signals located on multiple sub-frequencies into a Wideband Multiplexed Signal(WMS).Although WMSs were proposed initially to reduce the complexity of satellite transmitters and improve the transmission efficiency of signals,their multi-component structures and wide root mean square bandwidths introduced by high-frequency subcarriers also provide the possibility to improve the GNSS ranging ***,this paper proposes a Dual-assisted Multi-component Tracking(DMT)technique,which can not only fully use high-frequency subcarriers in WMSs,but also effectively track carrier,subcarrier,and code by jointly utilizing all components in *** this paper,the tracking and ranging performances of DMT are comprehensively analyzed theoretically and by simulation and real *** results show that compared with existing WMS tracking methods,DMT can achieve tracking results with lower tracking jitters and ranging results with higher precision,providing a highly advantageous solution for new generation GNSS signal processing.

关键词： Wideband multiplexed signal Dual-assisted Multi-component High precision tracking

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Subcarrier modulated navigation signal processing in GNSS:a review

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Satellite Navigation 2024年第3期5卷 1-18页

作者： Zheng Yao Yunhan Qi Mingquan Lu Department of Electronic Engineering Tsinghua UniversityBeijing100084China Beijing National Research Center for Information Science and Technology Beijing100084China

Subcarrier modulated signals are widely used in the new generation of Global Navigation Satellite Systems(GNSS)to improve spectral compatibility and ranging *** unique structure of subcarrier modulated signals poses an ambiguity threat to acquisition and tracking,rendering traditional GNSS signal processing algorithms *** unambiguous acquisition and tracking as well as observation extraction techniques for subcarrier modulated signals that can realize the high ranging accuracy potential while avoiding the ambiguity threat is a topic of common interest in both academia and *** studies have addressed the ambiguity elimination problem of subcarrier modulated ***,to the best of our knowledge,no updated reviews on this topic reflecting recent advances in the field have been presented in the past few *** the one hand,the unique composite subcarrier modulated signal structure in the B1 and B2 bands of the BeiDou Navigation Satellite System(BDS)and the E5 band of the Galileo satellite navigation system(Galileo)has been gradually emphasized by *** the other hand,unambiguous processing methods for subcarrier modulated signals based on multidimensional tracking loops have flourished,which provides a new way to solve the ambiguity *** overview of the most representative subcarrier modulated signal processing techniques,focusing on the achievements made in the last decade,is presented in this article,which can be a starting point for the researchers who start their study in this ***,we aim to present a complete review on the recent breakthroughs that have taken place within this research area,providing links to the most interesting and successful advances in this research *** challenges with prospects are also given.

关键词： Subcarrier modulated signals Binary offset carrier(BOC) Multiplexed binary offset carrier(MBOC) BeiDou Navigation Satellite System(BDS) Unambiguous processing

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Integrated diffractive optical neural network with space-time interleaving

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Chinese Optics Letters 2023年第9期21卷 84-90页

作者：符庭钊黄禹尧孙润黄泓皓刘文灿杨四刚陈宏伟 Beijing National Research Center for Information Science and Technology Department of Electronic EngineeringTsinghua UniversityBeijing 100084China

Integrated diffractive optical neural networks(DONNs)have significant potential for complex machine learning tasks with high speed and ultralow energy ***,the on-chip implementation of a high-performance optical neural network is limited by input *** contrast to existing photonic neural networks,a space-time interleaving technology based on arrayed waveguides is designed to realize an on-chip DONN with high-speed,high-dimensional,and all-optical input signal *** demonstrate the performance of the on-chip DONN with high-speed space-time interleaving modulation,an on-chip DONN with a designed footprint of 0.0945 mm~2is proposed to resolve the vowel recognition task,reaching a computation speed of about 1.4×10^(13)operations per second and yielding an accuracy of 98.3%in numerical *** addition,the function of the specially designed arrayed waveguides for realizing parallel signal inputs using space-time conversion has been verified *** method can realize the on-chip DONN with higher input dimension and lower energy consumption.

关键词： integrated diffractive optical neural networks machine learning arrayed waveguides

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NDN in tactical networks: An Adaptive Interface Status-Aware Forwarding Strategy 4

NDN in tactical networks: An Adaptive Interface Status-Aware...

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4th International Conference on Advanced Manufacturing technology and electronic information, AMTEI 2024

作者： Sun, Tianxiang Li, Ning Liu, Peng Zhou, Zeyu Information and Electronic Technology Department China Ship Research and Development Academy Beijing China

ISBN: (数字)9781510688247

ISBN: (纸本)9781510688230

Tactical networks, as a crucial component of the informationized battlefield, profoundly influence the speed of the OODA loop during warfare, playing a significant role in enhancing combat efficiency. Characterized by intermittent connectivity and the demand for lightweight protocols, tactical networks often experience suboptimal end-to-end transmission with traditional stateless routing protocols. To address this issue, this paper proposes an NDN-based adaptive interface status-aware forwarding strategy. By integrating the entropy weight method with the TOPSIS approach and considering static network conditions to calculate interface status scores, the strategy effectively identifies the most suitable output interface for interest packets. Additionally, a tournament algorithm is incorporated to prevent rapid degradation of interface performance. Simulation results demonstrate that, compared to other typical forwarding strategies, the proposed strategy performs better in terms of throughput, latency, and packet loss rate. © 2025 SPIE.

关键词： Packet loss

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