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Toward Constraintless Time-Correlated Single-Photon Counting Measurements: A New Method to Remove Pile-Up Distortion

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IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 2024年第1期30卷 1-12页

作者： Rech, Ivan Bovolenta, Angela Cominelli, Alessandro Acconcia, Giulia Politecn Milan Dept Elect Informat & Bioengn I-20133 Milan Italy Tecnosens SPA I-25125 Brescia Italy

Time-Correlated Single-Photon Counting (TCSPC) is a well-renowned technique allowing to reconstruct light signals with high sensitivity and resolution. Nevertheless, to this day, its use in applications requiring a fast analysis of the sample is limited due to its long acquisition time. The reason is twofold: on one hand, it is based on a statistical method thus requiring the collection of a large number of events to properly reconstruct the signal waveform;on the other hand, the average number of photons impinging on the sensor has to be kept particularly low to avoid artifacts. Indeed, the existence of dead time of both single-photon detectors and electronics can lead to distortion in the reconstructed waveform, which can be mitigated only if the count rate is kept below few percent of the excitation frequency. Recently, it has been demonstrated that an appropriate tuning of detector dead time allows to remove such power restriction, but, unfortunately, this constraint also sets a limit to the maximum count rate of the detector. In this paper, we present a novel method for TCSPC measurements, which ensures negligible distortion at unprecedented rates without requiring any constraint on either illumination power or detector dead time. We will show that this is possible thanks to the acquisition of additional information on the status of TCSPC system. The theoretical analysis reported in this paper is supported by analytical computation and numerical simulation, taking into account also potential non idealities of a real implementation.

关键词： Time-correlated single-photoncounting (TCSPC) pile-up speed enhancement correction algorithm

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New method of monitoring the transmission range of coal seam water injection and correcting the monitoring results

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MEASUREMENT 2021年 177卷

作者： Chen, Jian Cheng, Weimin Wang, Gang Li, Haomiao Li, Yanyan Shandong Univ Sci & Technol Mine Disaster Prevent & Control Minist State Key Lab Breeding Base Qingdao 266590 Peoples R China Univ Regina Fac Engn & Appl Sci 3737 Wascana Pkwy Regina SK Canada Huazhong Agr Univ Coll Engn Wuhan Hubei Peoples R China Chinese Acad Geol Sci Beijing 100037 Peoples R China

This study proposes a new experimental method of monitoring the transmission range of coal seam water injection on the basis of acoustic emission array monitoring technology. Through theoretical analysis and experimental verification, data on the characteristic signs that can confirm the water transmission to the monitoring path were found. In accordance with these data, the water transmission contour was enveloped. Subsequently, the water transmission's calculated distance, and fracture space parameters which were reconstructed by computed tomography (CT) scanning, were used to modify the control points of the water transmission contour. Results were compared with experimental slices to confirm the feasibility and correctness of the proposed monitoring technology. Furthermore, the threshold range of the wave parameter change when the water touches the monitoring path was determined in accordance with the range of the wave parameter change monitored in the effective monitoring path.

关键词： Acoustic emission array monitoring technology CT scan reconstruction Fracture P-wave Water transmission range monitoring correction algorithm

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Improving aerosol optical depth retrievals from Himawari-8 with ensemble learning enhancement: Validation over Asia

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ATMOSPHERIC RESEARCH 2023年 284卷

作者： Fu, Disong Gueymard, Christian A. Yang, Dazhi Zheng, Yu Xia, Xiangao Bian, Jianchun Chinese Acad Sci Inst Atmospher Phys Key Lab Middle Atmosphere & Global Environm Observ Beijing Peoples R China Univ Chinese Acad Sci Beijing Peoples R China Solar Consulting Serv Colebrook NH USA Harbin Inst Technol Sch Elect Engn & Automat Harbin Heilongjiang Peoples R China Chinese Acad Meteorol Sci State Key Lab Severe Weather LASW CMA Beijing Peoples R China Chinese Acad Meteorol Sci Key Lab Atmospher Chem LAC CMA Beijing Peoples R China

The Advanced Himawari Imager (AHI) onboard the Himawari-8 spacecraft from the Japan Meteorological Agency (JMA) enables retrieval of aerosol optical depth (AOD) with high spatio-temporal resolution. This work demonstrates that the latest version of Level-3 AHI AOD product is affected by an overall underestimation against ground measurements from 98 sunphotometer sites over Asia, with site-average R2 and mean bias error (MBE) of 0.54 and -0.10, respectively. The MBE varies from-0.23 to 0.03 over land, depending on site, and averages 0.06 over water. To correct these errors, an XGBoost model has been developed based on the AHI AOD, as well as meteorological quantities and geographic information from the ERA5 ECMWF reanalysis, a digital elevation model (DEM), and ground-based AOD measurements obtained in 2018. After application of this correction al-gorithm, the testing dataset indicates that R2 and the fraction of data included within the expected error (EE) envelope (+/- 15%) are 0.86 and 74.7%, respectively, thus representing substantial improvement compared to the corresponding uncorrected results of 0.59 and 42.2%. The optimal XGBoost also demonstrates a good general-ization ability because 69.5% of the corrected AOD falls within the EE envelope when applying the model to AHI data from 2019. The model's Feature Importance analysis shows that, besides the raw AHI AOD, geographic coordinates, surface albedo, and atmospheric water vapor contribute significantly to the correction model. The AOD difference map (corrected AOD minus raw AHI AOD) reveals that the XGBoost model improves AOD values considerably for land areas by 0.14, 0.10, 0.09, and 0.11 for MAM, JJA, SON and DJF, respectively.

关键词： Himawari-8 AOD CARSNET AERONET XGBoost correction algorithm

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A model-based Bayesian framework for ECG beat segmentation

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PHYSIOLOGICAL MEASUREMENT 2009年第3期30卷 335-352页

作者： Sayadi, O. Shamsollahi, M. B. Sharif Univ Technol Sch Elect Engn Biomed Signal & Image Proc Lab BiSIPL Tehran Iran

The study of electrocardiogram (ECG) waveform amplitudes, timings and patterns has been the subject of intense research, for it provides a deep insight into the diagnostic features of the heart's functionality. In some recent works, a Bayesian filtering paradigm has been proposed for denoising and compression of ECG signals. In this paper, it is shown that this framework may be effectively used for ECG beat segmentation and extraction of fiducial points. Analytic expressions for the determination of points and intervals are derived and evaluated on various real ECG signals. Simulation results show that the method can contribute to and enhance the clinical ECG beat segmentation performance.

关键词： correction algorithm ECG dynamical model extended Kalman filter fluctuating estimates fiducial points extraction segmentation

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Numerical Integration with Constraints for Mesh less Local Petrov-Galerkin Methods

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CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES 2013年第3期95卷 205-228页

作者： Sun, L. Yang, G. Zhang, Q. Guangdong Univ Petrochem Technol Sch Sci Maoming 525000 Guangdong Peoples R China Zhongyuan Univ Technol Sch Comp Sci Zhengzhou 450007 Peoples R China Sun Yat Sen Univ Guangdong Prov Key Lab Computat Sci Guangzhou 510275 Guangdong Peoples R China Sun Yat Sen Univ Dept Sci Comp & Comp Applicat Guangzhou 510275 Guangdong Peoples R China

We propose numerical integration rules for meshless local Petrov-Galerkin methods (MLPG) employed to solve elliptic partial different equations (PDE) with Neumann boundary conditions. The integration rules are required to satisfy an integration constraint condition of Green's formula type (GIC). GIC was first developed in [Babuska, Banerjee, Osborn, and Zhang (2009)] for Galerkin meshless method, and we will show in this paper that it has better features for MLPG due to flexibility of MLPG in choosing different trial and test function spaces. A general constructive algorithm is presented to design the integration rules satisfying GIC. We also present a useful situation, where GIC holds automatically for Gaussian rules. According to this, we conclude that the conical weight is suggested to adopt in MLPG from viewpoint of reducing integration complexity. Approach to extending GIC in [Babuska, Banerjee, Osborn, and Zhang (2009)] to more general elliptic PDE, such as elasticity equation, is discussed. The 1D and 2D numerical results illuminate that GIC reduces the errors in the approximate solutions of MLPG significantly.

关键词： Meshless Petrov-Galerkin method (MLPG) numerical integration integration constraint Green's formula correction algorithm conical weight

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High-Precision Temperature Inversion algorithm for Correlative Microwave Radiometer

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SENSORS 2021年第16期21卷 5336页

作者： Liu, Jie Zhang, Kai Ma, Jingyan Wu, Qiang Sun, Zhenlin Wang, Hao Zhang, Youquan Beijing Univ Technol Fac Informat Technol Beijing 100124 Peoples R China

In order to achieve high precision from non-contact temperature measurement, the hardware structure of a broadband correlative microwave radiometer, calibration algorithm, and temperature inversion algorithm are innovatively designed in this paper. The correlative radiometer is much more sensitive than a full power radiometer, but its accuracy is challenging to improve due to relatively large phase error. In this study, an error correction algorithm is designed, which reduces the phase error from 69.08 degrees to 4.02 degrees. Based on integral calibration on the microwave temperature measuring system with a known radiation source, the linear relationship between the output voltage and the brightness temperature of the object is obtained. Since the metal aluminum plate, antenna, and transmission line will have a non-linear influence on the receiver system, their temperature characteristics and the brightness temperature of the object are used as the inputs of the neural network to obtain a higher accuracy of inversion temperature. The temperature prediction mean square error of a back propagation (BP) neural network is 0.629 degrees C, and its maximum error is 3.351 degrees C. This paper innovatively proposed the high-precision PSO-LM-BP temperature inversion algorithm. According to the global search ability of the particle swarm optimization (PSO) algorithm, the initial weight of the network can be determined effectively, and the Levenberg-Marquardt (LM) algorithm makes use of the second derivative information, which has higher convergence accuracy and iteration efficiency. The mean square error of the PSO-LM-BP temperature inversion algorithm is 0.002 degrees C, and its maximum error is 0.209 degrees C.

关键词： correlative radiometer correction algorithm integral calibration PSO-LM-BP inversion algorithm

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Optimization for thermal rating method of high voltage cable considering the existence of air gap

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ELECTRIC POWER SYSTEMS RESEARCH 2023年 217卷

作者： Wang, Pengyu Guangdong Polytech Normal Univ Sch Automation Guangzhou Peoples R China

To prevent the damage caused by the bending phenomenon of cable, the air gap is reserved between the buffer layer and the aluminum sheath, which results in the cable with non-centrosymmetric structure. However, in the traditional IEC method, the structure between the insulation and the aluminum sheath is simply treated as the lining layer regardless of the influence of air gap. To remedy this issue, in this paper the real temperature test and simulation analysis for cable with non-centrosymmetric structure were conducted to clarify the main error source of the traditional IEC method and the influence of air gap thickness on the error. The discussions on the radial thermal expansion phenomenon in the cable and its effect on the thermal parameters of cable were also declared. The correction algorithm for the thermal resistance of lining layer considering the dynamic shape factor was proposed. Furthermore, the optimized thermal evaluation of cable was realized combined with the correction algorithm and the traditional IEC method. The accuracy and superiority of the improved method were verified by the real cable test. The results show that the improved method shows a satisfactory performance in the thermal rating for cable with non-centrosymmetric structure.

关键词： Cable thermal rating Non-centrosymmetric structure Lining layer Air gap correction algorithm

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Smartphone Location-Independent Physical Activity Recognition Based on Transportation Natural Vibration Analysis

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SENSORS 2017年第4期17卷 931-931页

作者： Hur, Taeho Bang, Jaehun Kim, Dohyeong Banos, Oresti Lee, Sungyoung Kyung Hee Univ Dept Comp Sci & Engn Global Campus1732Deogyeong Daero Yongin 17104 Gyeonggi Do South Korea Univ Twente Telemed Cluster Biomed Signals & Syst Grp NL-7500 AE Enschede Netherlands

Activity recognition through smartphones has been proposed for a variety of applications. The orientation of the smartphone has a significant effect on the recognition accuracy;thus, researchers generally propose using features invariant to orientation or displacement to achieve this goal. However, those features reduce the capability of the recognition system to differentiate among some specific commuting activities (e.g., bus and subway) that normally involve similar postures. In this work, we recognize those activities by analyzing the vibrations of the vehicle in which the user is traveling. We extract natural vibration features of buses and subways to distinguish between them and address the confusion that can arise because the activities are both static in terms of user movement. We use the gyroscope to fix the accelerometer to the direction of gravity to achieve an orientation-free use of the sensor. We also propose a correction algorithm to increase the accuracy when used in free living conditions and a battery saving algorithm to consume less power without reducing performance. Our experimental results show that the proposed system can adequately recognize each activity, yielding better accuracy in the detection of bus and subway activities than existing methods.

关键词： movement activity recognition vehicle natural vibration natural vibration feature extraction correction algorithm smartphone

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Design and Implementation of a Novel Interferometric Microwave Radiometer for Human Body Temperature Measurement

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SENSORS 2021年第5期21卷 1619页

作者： Sun, Guangmin Ma, Pan Liu, Jie Shi, Chong Ma, Jingyan Peng, Li Beijing Univ Technol Fac Informat Technol Beijing 100124 Peoples R China

In this paper, the key technology of interferometric microwave thermometer is studied, the research can be applied to the temperature measurement of human body and subcutaneous tissue. This paper proposes a hardware architecture of interferometric microwave thermometer with 2 GHz bandwidth, in which the phase shifter is used to correct phase error and the quadrature demodulator is used to realize autocorrelation detection function. The results show that when input power is 7 dBm, the detection sensitivity can reach 176.54 mV/dBm and the temperature resolution of the microwave radiometer can reach 0.4 K. correction algorithm is designed to improve the accuracy of temperature measurement. After correction, the phase error is reduced from 40 degrees to 1.4 degrees and when temperature changes 0.1 degrees C, the voltage value changes obviously. Step-by-step calibration and overall calibration are used to calibrate the device. Inversion algorithm can determine the relationship between physical temperature and output voltage. The mean square error of water temperature inversion by multiple linear regression algorithm is 0.607 and that of BP neural network algorithm is 0.334. The inversion accuracy can be improved by reducing the temperature range. Our work provides a promising realization of accurate, rapid and non-contact detection device of human body temperature.

关键词： interferometric microwave radiometer correction algorithm calibration inversion algorithm neural network

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Variation Tendency of Coastline under Natural and Anthropogenic Disturbance around the Abandoned Yellow River Delta in 1984-2019

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REMOTE SENSING 2021年第17期13卷

作者： Sun, Zhipeng Niu, Xiaojing Tsinghua Univ Dept Hydraul Engn State Key Lab Hydrosci & Engn Beijing 100084 Peoples R China

The coast around the Abandoned Yellow River Delta underwent significant changes under anthropogenic disturbance. This study aims to reveal the variation of the coastline, tidal flat area, and intertidal zone slope before, during, and after extensive reclamation during the period of 1984-2019 using satellite remote sensing images. In order to eliminate the influence of the varying water level, a new coastline correction algorithm had been proposed under the condition of insufficient accurate slope and water level data. The influence of seawalls on slope estimation were considered in it. The spatiotemporal evolution of coast had been analyzed and confirmed to be reasonable by comparing with the observed data. The results show that the coast can be roughly divided into a north erosion part and a south deposition part. Affected by reclamation, their tidal flat area in 2019 is reduced to only 43 and 27% of original area in 1984, respectively, which results in a continuous decrease in the tidal flat width. The adjustment of the tidal flat profile makes the slopes steeper in the erosion part, while the slopes in the deposition part remain stable. The reclamation has stimulated a cumulative effect as the disappearance of the intertidal zone, which may lead to the destruction of biological habitats.

关键词： Abandoned Yellow River Delta remote sensing images spatiotemporal changes correction algorithm coastline tidal flat

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