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Longitudinal Performance Assessment of Traffic Signal System Impacted by Long-Term Interstate Construction Diversion Using Connected Vehicle Data 被引量:6
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作者 Enrique D. Saldivar-Carranza Margaret Hunter +2 位作者 Howell Li Jijo Mathew Darcy M. Bullock 《Journal of Transportation Technologies》 2021年第4期644-659,共16页
Local arterials can be significantly impacted by diversions from adjacent work zones. These diversions often occur on unofficial detour routes due to guidance received on personal navigation devices. Often, these rout... Local arterials can be significantly impacted by diversions from adjacent work zones. These diversions often occur on unofficial detour routes due to guidance received on personal navigation devices. Often, these routes do not have sufficien<span style="font-family:Verdana;">t sensing or communication equipment to obtain infrastructure-based tra</span><span style="font-family:Verdana;">ffic signal performance measures, so other data sources are required to identify locations being significantly affected by diversions. This paper examines the network impact caused by the start of an 18-month closure of the I-65/70 interchange (North Split), which usually serves approximately 214,000 vehicles per day in Indianapolis, IN. In anticipation of some proportion of the public diverting from official detour routes to local streets, a connected vehicle monitoring program was established to provide daily performances measures for over 100 intersections in the area without the need for vehicle sensing equipment. This study reports on 13 of the most impacted signals on an alternative arterial to identify locations and time of day where operations are most degraded, so that decision makers have quantitative information to make informed adjustments to the system. Individual vehicle movements at the studied locations are analyzed to estimate changes in volume, split failures, downstream blockage, arrivals on green, and travel times. Over 130,000 trajectories were analyzed in an 11-week period. Weekly afternoon peak period volumes increased by approximately 455%, split failures increased 3%, downstream blockage increased 10%, arrivals on green decreased 16%, and travel time increase 74%. The analysis performed in this paper will serve as a framework for any agency that wants to assess traffic signal performance at hundreds of locations with little or no existing sensing or communication infrastructure to prioritize tactical retiming and/or longer-term infrastructure investments.</span> 展开更多
关键词 Traffic signal Performance Measures Connected Vehicle Longitudinal Study Big Data
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Nickel Sulfide/Graphene/Carbon Nanotube Composites as Electrode Material for the Supercapacitor Application in the Sea Flashing Signal System
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作者 Hailong Chen Ji Li +4 位作者 Conglai Long Tong Wei Guoqing Ning Jun Yan Zhuangjun Fan 《Journal of Marine Science and Application》 2014年第4期462-466,共5页
这个工作介绍 NiS/graphene/carbon nanotube (NiS/GNS/CNT ) 是的 composites 为在海闪光的 supercapacitor 应用程序的电极材料信号系统。NiS nanosheets 仔细在传导性的 GNS-CNT 网络上被抛锚。作为结果, NiS/GNS/CNT 电极显示出 2 ... 这个工作介绍 NiS/graphene/carbon nanotube (NiS/GNS/CNT ) 是的 composites 为在海闪光的 supercapacitor 应用程序的电极材料信号系统。NiS nanosheets 仔细在传导性的 GNS-CNT 网络上被抛锚。作为结果, NiS/GNS/CNT 电极显示出 2 377 F 的一个高特定的电容 ? 獵湩 ? 剘? 湡 ? 桴 ? 楰瑴湩 ? 湯愠畬業楮浵愠 ?? 敲?瑬漠 ? 慧癬湡捩挠牯潲楳湯眠獡栠杩汨杩?摥椠 ? 整浲 ? 景瀠瑩搠灥桴 ? 楳敺愠摮搠湥楳祴漠 ? 楰? 甠楳杮愠栠杩 ?敲潳畬楴湯洠捩潲 ' 展开更多
关键词 碳纳米管复合材料 超级电容器 信号系统 电极材料 硫化镍 应用 闪烁 石墨
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Integrated Performance Measures for Bus Rapid Transit System and Traffic Signal Systems Using Trajectory Data
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作者 Jijo Kulathintekizhakethil Mathew Howell Li +2 位作者 Enrique Saldivar-Carrranza Matthew Duffy Darcy Michael Bullock 《Journal of Transportation Technologies》 2022年第4期833-860,共28页
Bus rapid transit (BRT) systems have been implemented in many cities over the past two decades. Widespread adoption of General Transit Feed Specification (GTFS), the deployment of high-fidelity bus GPS data tracking, ... Bus rapid transit (BRT) systems have been implemented in many cities over the past two decades. Widespread adoption of General Transit Feed Specification (GTFS), the deployment of high-fidelity bus GPS data tracking, and anonymized high-fidelity connected vehicle data from private vehicles have provided new opportunities for performance measures that can be used by both transit agencies and traffic signal system operators. This paper describes the use of trajectory-based data to develop performance measures for a BRT system in Indianapolis, Indiana. Over 3 million data records during the 3-month period between March and May 2022 are analyzed to develop visualizations and performance metrics. A methodology to estimate the average delay and schedule adherence is presented along a route comprised of 74 signals and 28 bus stations. Additionally, this research demonstrates how these performance measures can be used to evaluate dedicated and non-dedicated bus lanes with general traffic. Travel times and reliability of buses are compared with nearly 30 million private vehicle trips. Results show that median travel time for buses on dedicated bi-directional lanes is within one minute of general traffic and during peak periods the buses are often faster. Schedule adherence was observed to be more challenging, with approximately 3% of buses arriving within 1 minute on average during the 5AM hour and 5% of buses arriving 6 - 9 minutes late during the 5PM hour. The framework and performance measures presented in this research provide agencies and transportation professionals with tools to identify opportunities for adjustments and to justify investment decisions. 展开更多
关键词 Connected Vehicle Trajectory Bus Rapid Transit Performance Traffic signal Retiming Schedules
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The Study of Fuzzy Line Control for Intelligent Transportation Signal System
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作者 Mingqing Jiang Zhong Gui Xixia Fang 《通讯和计算机(中英文版)》 2005年第9期9-11,21,共4页
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Digital signal acquisition system for complex nuclear reaction experiments
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作者 Wei-Liang Pu Yan-Lin Ye +1 位作者 Jian-Ling Lou Jia-Hao Chen 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第1期124-133,共10页
A digital data-acquisition system based on XIA LLC products was used in a complex nuclear reaction experiment using radioactive ion beams.A flexible trigger system based on a field-programmable gate array(FPGA)paramet... A digital data-acquisition system based on XIA LLC products was used in a complex nuclear reaction experiment using radioactive ion beams.A flexible trigger system based on a field-programmable gate array(FPGA)parametrization was developed to adapt to different experimental sizes.A user-friendly interface was implemented,which allows converting script language expressions into FPGA internal control parameters.The proposed digital system can be combined with a conventional analog data acquisition system to provide more flexibility.The performance of the combined system was veri-fied using experimental data. 展开更多
关键词 Digital signal acquisition system TRIGGER Programmable logic TIMESTAMP
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Deep Learning Based Signal Detector for OFDM Systems 被引量:1
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作者 Guangliang Pan Wei Wang Minglei Li 《China Communications》 SCIE CSCD 2023年第12期66-77,共12页
In this paper,we propose a novel deep learning(DL)-based receiver design for orthogonal frequency division multiplexing(OFDM)systems.The entire process of channel estimation,equalization,and signal detection is replac... In this paper,we propose a novel deep learning(DL)-based receiver design for orthogonal frequency division multiplexing(OFDM)systems.The entire process of channel estimation,equalization,and signal detection is replaced by a neural network(NN),and hence,the detector is called a NN detector(N^(2)D).First,an OFDM signal model is established.We analyze both temporal and spectral characteristics of OFDM signals,which are the motivation for DL.Then,the generated data based on the simulation of channel statistics is used for offline training of bi-directional long short-term memory(Bi-LSTM)NN.Especially,a discriminator(F)is added to the input of Bi-LSTM NN to look for subcarrier transmission data with optimal channel gain(OCG),which can greatly improve the performance of the detector.Finally,the trained N^(2)D is used for online recovery of OFDM symbols.The performance of the proposed N^(2)D is analyzed theoretically in terms of bit error rate(BER)by Monte Carlo simulation under different parameter scenarios.The simulation results demonstrate that the BER of N^(2)D is obviously lower than other algorithms,especially at high signal-to-noise ratios(SNRs).Meanwhile,the proposed N^(2)D is robust to the fluctuation of parameter values. 展开更多
关键词 channel estimation deep learning OFDM optimal channel gain signal detection
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Purinergic signaling systems across comparative models of spinal cord injury
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作者 Eva E.Stefanova Angela L.Scott 《Neural Regeneration Research》 SCIE CAS CSCD 2023年第3期689-696,共8页
Within the last several decades,the scientific community has made substantial progress in elucidating the complex pathophysiology underlying spinal cord injury.However,despite the many advances using conventional mamm... Within the last several decades,the scientific community has made substantial progress in elucidating the complex pathophysiology underlying spinal cord injury.However,despite the many advances using conventional mammalian models,both cellular and axonal regeneration following spinal cord injury have remained out of reach.In this sense,turning to non-mammalian,regenerative species presents a unique opportunity to identify pro-regenerative cues and characterize a spinal cord microenvironment permissive to re-growth.Among the signaling pathways hypothesized to be dysregulated during spinal cord injury is the purinergic signaling system.In addition to its well-known role as energy currency in cells,ATP and its metabolites are small molecule neurotransmitters that mediate many diverse cellular processes within the central nervous system.While our understanding of the roles of the purinergic system following spinal cord injury is limited,this signaling pathway has been implicated in all injury-induced secondary processes,including cellular death,inflammation,reactive gliosis,and neural regeneration.Given that the purinergic system is also evolutionarily conserved between mammalian and non-mammalian species,comparisons of these roles may provide important insights into conditions responsible for recovery success.Here,we compare the secondary processes between key model species and the influence of purinergic signaling in each context.As our understanding of this signaling system and pro-regenerative conditions continues to evolve,so does the potential for the development of novel therapeutic interventions for spinal cord injury. 展开更多
关键词 cell death differentiation GLIA inflammation NEUROGENESIS proliferation purinergic signaling reactive gliosis regeneration spinal cord injury TELEOST
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Hypoglycemic mechanism of Tegillarca granosa polysaccharides on type 2 diabetic mice by altering gut microbiota and regulating the PI3K-akt signaling pathwaye 被引量:1
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作者 Qihong Jiang Lin Chen +5 位作者 Rui Wang Yin Chen Shanggui Deng Guoxin Shen Shulai Liu Xingwei Xiang 《Food Science and Human Wellness》 SCIE CSCD 2024年第2期842-855,共14页
Type 2 diabetes mellitus(T2DM)is a complex metabolic disease threatening human health.We investigated the effects of Tegillarca granosa polysaccharide(TGP)and determined its potential mechanisms in a mouse model of T2... Type 2 diabetes mellitus(T2DM)is a complex metabolic disease threatening human health.We investigated the effects of Tegillarca granosa polysaccharide(TGP)and determined its potential mechanisms in a mouse model of T2DM established through a high-fat diet and streptozotocin.TGP(5.1×10^(3) Da)was composed of mannose,glucosamine,rhamnose,glucuronic acid,galactosamine,glucose,galactose,xylose,and fucose.It could significantly alleviate weight loss,reduce fasting blood glucose levels,reverse dyslipidemia,reduce liver damage from oxidative stress,and improve insulin sensitivity.RT-PCR and Western blotting indicated that TGP could activate the phosphatidylinositol-3-kinase/protein kinase B signaling pathway to regulate disorders in glucolipid metabolism and improve insulin resistance.TGP increased the abundance of Allobaculum,Akkermansia,and Bifidobacterium,restored the microbiota abundance in the intestinal tracts of mice with T2DM,and promoted short-chain fatty acid production.This study provides new insights into the antidiabetic effects of TGP and highlights its potential as a natural hypoglycemic nutraceutical. 展开更多
关键词 Tegillarca granosa polysaccharide Type 2 diabetes mellitus Glycolipid metabolism PI3K/Akt signaling pathway
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Automatic depression recognition by intelligent speech signal processing:A systematic survey
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作者 Pingping Wu Ruihao Wang +3 位作者 Han Lin Fanlong Zhang Juan Tu Miao Sun 《CAAI Transactions on Intelligence Technology》 SCIE EI 2023年第3期701-711,共11页
Depression has become one of the most common mental illnesses in the world.For better prediction and diagnosis,methods of automatic depression recognition based on speech signal are constantly proposed and updated,wit... Depression has become one of the most common mental illnesses in the world.For better prediction and diagnosis,methods of automatic depression recognition based on speech signal are constantly proposed and updated,with a transition from the early traditional methods based on hand‐crafted features to the application of architectures of deep learning.This paper systematically and precisely outlines the most prominent and up‐to‐date research of automatic depression recognition by intelligent speech signal processing so far.Furthermore,methods for acoustic feature extraction,algorithms for classification and regression,as well as end to end deep models are investigated and analysed.Finally,general trends are summarised and key unresolved issues are identified to be considered in future studies of automatic speech depression recognition. 展开更多
关键词 acoustic signal processing deep learning feature extraction speech depression recognition
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Nonbinary ldpc-coded probabilistic shaping scheme for MIMO systems based on signal space diversity
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作者 Weimin Kang 《Digital Communications and Networks》 SCIE CSCD 2023年第3期779-787,共9页
This paper first describes a binary Low-Density Parity-Check(LDPC)-coded Probabilistic Shaping(PS)scheme for Multiple-Input Multiple-Output(MIMO)systems based on Signal Space Diversity(SSD).Second,a Nonbinary(NB)LDPC-... This paper first describes a binary Low-Density Parity-Check(LDPC)-coded Probabilistic Shaping(PS)scheme for Multiple-Input Multiple-Output(MIMO)systems based on Signal Space Diversity(SSD).Second,a Nonbinary(NB)LDPC-coded PS scheme for MIMO systems based on SSD is proposed.The first scheme can be used to obtain a shaping gain,whereas the second can also realize a coding gain.The theoretical average mutual information of the optimized rotated quadrature amplitude modulation constellations is analyzed and the simulated error per-formance with 22 and 44 MIMO schemes is investigated.The theoretical average mutual information analysis and simulation results show that the proposed NB LDPC-coded PS scheme for MIMO systems based on SSD is reliable and robust,and is therefore suitable for future wireless communication systems. 展开更多
关键词 Probabilistic shaping Multiple-input multiple-output signal space diversity Average mutual information
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Signal Conducting System with Effective Optimization Using Deep Learning for Schizophrenia Classification
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作者 V.Divya S.Sendil Kumar +1 位作者 V.Gokula Krishnan Manoj Kumar 《Computer Systems Science & Engineering》 SCIE EI 2023年第5期1869-1886,共18页
Signal processing based research was adopted with Electroencephalogram(EEG)for predicting the abnormality and cerebral activities.The proposed research work is intended to provide an automatic diagnostic system to det... Signal processing based research was adopted with Electroencephalogram(EEG)for predicting the abnormality and cerebral activities.The proposed research work is intended to provide an automatic diagnostic system to determine the EEG signal in order to classify the brain function which shows whether a person is affected with schizophrenia or not.Early detection and intervention are vital for better prognosis.However,the diagnosis of schizophrenia still depends on clinical observation to date.Without reliable biomarkers,schizophrenia is difficult to detect in its early phase and hence we have proposed this idea.In this work,the EEG signal series are divided into non-linear feature mining,classification and validation,and t-test integrated feature selection process.For this work,19-channel EEG signals are utilized from schizophrenia class and normal pattern.Here,the datasets initially execute the splitting process based on raw 19-channel EEG into 6250 sample point’s sequences.With this process,1142 features of normal and schizophrenia class patterns can be obtained.In other hand,157 features from each EEG patterns are utilized based on Non-linear feature extraction process where 14 principal features can be identified in terms of considering the essential features.At last,the Deep Learning(DL)technique incorporated with an effective optimization technique is adopted for classification process called a Deep Convolutional Neural Network(DCNN)with mayfly optimization algorithm.The proposed technique is implemented into the platform of MATLAB in order to obtain better results and is analyzed based on the performance analysis framework such as accuracy,Signal to Noise Ratio(SNR),Mean Square Error,Normalized Mean Square Error(NMSE)and Loss.Through comparison,the proposed technique is proved to a better technique than other existing techniques. 展开更多
关键词 Deep learning optimization algorithm signal conducting system SCHIZOPHRENIA convolutional neural network mayfly optimization algorithm
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Analysis of Additional Damping Control Strategy and Parameter Optimization for Improving Small Signal Stability of VSC-HVDC System
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作者 Hui Fang Jingsen Zhou +3 位作者 Hanjie Liu Yanxu Wang Hongji Xiang Yechun Xin 《Energy Engineering》 EI 2023年第4期931-948,共18页
The voltage source converter based high voltage direct current(VSC-HVDC)system is based on voltage source converter,and its control system is more complex.Also affected by the fast control of power electronics,oscilla... The voltage source converter based high voltage direct current(VSC-HVDC)system is based on voltage source converter,and its control system is more complex.Also affected by the fast control of power electronics,oscillation phenomenon in wide frequency domain may occur.To address the problem of small signal stability of the VSCHVDC system,a converter control strategy is designed to improve its small signal stability,and the risk of system oscillation is reduced by attaching a damping controller and optimizing the control parameters.Based on the modeling of the VSC-HVDC system,the general architecture of the inner and outer loop control of the VSCHVDC converter is established;and the damping controllers for DC control and AC control are designed in the phase-locked loop and the inner and outer loop control parts respectively;the state-space statemodel of the control system is established to analyze its performance.And the electromagnetic transient simulation model is built on the PSCAD/EMTDC simulation platform to verify the accuracy of the small signal model.The influence of the parameters of each control part on the stability of the system is summarized.The main control parts affecting stability are optimized for the phenomenon of oscillation due to changes in operation mode occurring on the AC side due to faults and other reasons,which effectively eliminates system oscillation and improves system small signal stability,providing a certain reference for engineering design. 展开更多
关键词 VSC-HVDC system small signal modeling eigenvalue analysis parameter optimization
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Design and Simulation of an Audio Signal Alerting and Automatic Control System
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作者 Winfred Adjardjah John Awuah Addor +1 位作者 Wisdom Opare Isaac Mensah Ayipeh 《Communications and Network》 2023年第4期98-119,共22页
A large part of our daily lives is spent with audio information. Massive obstacles are frequently presented by the colossal amounts of acoustic information and the incredibly quick processing times. This results in th... A large part of our daily lives is spent with audio information. Massive obstacles are frequently presented by the colossal amounts of acoustic information and the incredibly quick processing times. This results in the need for applications and methodologies that are capable of automatically analyzing these contents. These technologies can be applied in automatic contentanalysis and emergency response systems. Breaks in manual communication usually occur in emergencies leading to accidents and equipment damage. The audio signal does a good job by sending a signal underground, which warrants action from an emergency management team at the surface. This paper, therefore, seeks to design and simulate an audio signal alerting and automatic control system using Unity Pro XL to substitute manual communication of emergencies and manual control of equipment. Sound data were trained using the neural network technique of machine learning. The metrics used are Fast Fourier transform magnitude, zero crossing rate, root mean square, and percentage error. Sounds were detected with an error of approximately 17%;thus, the system can detect sounds with an accuracy of 83%. With more data training, the system can detect sounds with minimal or no error. The paper, therefore, has critical policy implications about communication, safety, and health for underground mine. 展开更多
关键词 Emergency Response Emergency Management Team Audio signal Alerting Automatic Control system Uni Pro XL Manual Communication Fast Fourier Transform Magnitude Zero Crossing Rate Root Means Square
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A feedback control method for phase signal demodulation in fber-optic hydrophones
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作者 Zhiqiang LIU Lei XIA +3 位作者 Qiangfeng LYU Bin WU Ronghua HUAN Zhilong HUANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第3期515-528,共14页
In the realm of acoustic signal detection,the identification of weak signals,particularly in the presence of negative signal-to-noise ratios,poses a significant challenge.This challenge is further heightened when sign... In the realm of acoustic signal detection,the identification of weak signals,particularly in the presence of negative signal-to-noise ratios,poses a significant challenge.This challenge is further heightened when signals are acquired through fiber-optic hydrophones,as these signals often lack physical significance and resist clear systematic modeling.Conventional processing methods,e.g.,low-pass filter(LPF),require a thorough understanding of the effective signal bandwidth for noise reduction,and may introduce undesirable time lags.This paper introduces an innovative feedback control method with dual Kalman filters for the demodulation of phase signals with noises in fiber-optic hydrophones.A mathematical model of the closed-loop system is established to guide the design of the feedback control,aiming to achieve a balance with the input phase signal.The dual Kalman filters are instrumental in mitigating the effects of signal noise,observation noise,and control execution noise,thereby enabling precise estimation for the input phase signals.The effectiveness of this feedback control method is demonstrated through examples,showcasing the restoration of low-noise signals,negative signal-to-noise ratio signals,and multi-frequency signals.This research contributes to the technical advancement of high-performance devices,including fiber-optic hydrophones and phase-locked amplifiers. 展开更多
关键词 feedback control method fiber-optic hydrophone acoustic signal detection phase signal
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2D DOA Estimation of Coherent Signals with a Separated Linear Acoustic Vector-Sensor Array
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作者 Sheng Liu Jing Zhao +2 位作者 Decheng Wu Yiwang Huang Kaiwu Luo 《China Communications》 SCIE CSCD 2024年第2期155-165,共11页
In this paper, a two-dimensional(2D) DOA estimation algorithm of coherent signals with a separated linear acoustic vector-sensor(AVS) array consisting of two sparse AVS arrays is proposed. Firstly,the partitioned spat... In this paper, a two-dimensional(2D) DOA estimation algorithm of coherent signals with a separated linear acoustic vector-sensor(AVS) array consisting of two sparse AVS arrays is proposed. Firstly,the partitioned spatial smoothing(PSS) technique is used to construct a block covariance matrix, so as to decorrelate the coherency of signals. Then a signal subspace can be obtained by singular value decomposition(SVD) of the covariance matrix. Using the signal subspace, two extended signal subspaces are constructed to compensate aperture loss caused by PSS.The elevation angles can be estimated by estimation of signal parameter via rotational invariance techniques(ESPRIT) algorithm. At last, the estimated elevation angles can be used to estimate automatically paired azimuth angles. Compared with some other ESPRIT algorithms, the proposed algorithm shows higher estimation accuracy, which can be proved through the simulation results. 展开更多
关键词 acoustic vector-sensor coherent signals extended signal subspace sparse array
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Adaptive Bistable Stochastic Resonance Based Weak Signal Reception in Additive Laplacian Noise
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作者 Jin Liu Zan Li +1 位作者 Qiguang Miao Li Yang 《China Communications》 SCIE CSCD 2024年第1期228-241,共14页
Weak signal reception is a very important and challenging problem for communication systems especially in the presence of non-Gaussian noise,and in which case the performance of optimal linear correlated receiver degr... Weak signal reception is a very important and challenging problem for communication systems especially in the presence of non-Gaussian noise,and in which case the performance of optimal linear correlated receiver degrades dramatically.Aiming at this,a novel uncorrelated reception scheme based on adaptive bistable stochastic resonance(ABSR)for a weak signal in additive Laplacian noise is investigated.By analyzing the key issue that the quantitative cooperative resonance matching relationship between the characteristics of the noisy signal and the nonlinear bistable system,an analytical expression of the bistable system parameters is derived.On this basis,by means of bistable system parameters self-adaptive adjustment,the counterintuitive stochastic resonance(SR)phenomenon can be easily generated at which the random noise is changed into a benefit to assist signal transmission.Finally,it is demonstrated that approximately 8dB bit error ratio(BER)performance improvement for the ABSR-based uncorrelated receiver when compared with the traditional uncorrelated receiver at low signal to noise ratio(SNR)conditions varying from-30dB to-5dB. 展开更多
关键词 adaptive bistable stochastic resonance additive Laplacian noise low signal to noise ratio uncorrelated reception scheme weak signal reception
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Machine Learning for Signal Demodulation in Underwater Wireless Optical Communications
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作者 Ma Shuai Yang Lei +6 位作者 Ding Wanying Li Hang Zhang Zhongdan Xu Jing Li Zongyan Xu Gang Li Shiyin 《China Communications》 SCIE CSCD 2024年第5期297-313,共17页
The underwater wireless optical communication(UWOC)system has gradually become essential to underwater wireless communication technology.Unlike other existing works on UWOC systems,this paper evaluates the proposed ma... The underwater wireless optical communication(UWOC)system has gradually become essential to underwater wireless communication technology.Unlike other existing works on UWOC systems,this paper evaluates the proposed machine learningbased signal demodulation methods through the selfbuilt experimental platform.Based on such a platform,we first construct a real signal dataset with ten modulation methods.Then,we propose a deep belief network(DBN)-based demodulator for feature extraction and multi-class feature classification.We also design an adaptive boosting(Ada Boost)demodulator as an alternative scheme without feature filtering for multiple modulated signals.Finally,it is demonstrated by extensive experimental results that the Ada Boost demodulator significantly outperforms the other algorithms.It also reveals that the demodulator accuracy decreases as the modulation order increases for a fixed received optical power.A higher-order modulation may achieve a higher effective transmission rate when the signal-to-noise ratio(SNR)is higher. 展开更多
关键词 ADABOOST DBN machine learning signal demodulation
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Effect of preload forces on multidimensional signal dynamic behaviours for battery early safety warning
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作者 Kuijie Li Jiahua Li +10 位作者 Xinlei Gao Yao Lu Depeng Wang Weixin Zhang Weixiong Wu Xuebing Han Yuan-cheng Cao Languang Lu Jinyu Wen Shijie Cheng Minggao Ouyang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第5期484-498,共15页
Providing early safety warning for batteries in real-world applications is challenging.In this study,comprehensive thermal abuse experiments are conducted to clarify the multidimensional signal evolution of battery fa... Providing early safety warning for batteries in real-world applications is challenging.In this study,comprehensive thermal abuse experiments are conducted to clarify the multidimensional signal evolution of battery failure under various preload forces.The time-sequence relationship among expansion force,voltage,and temperature during thermal abuse under five categorised stages is revealed.Three characteristic peaks are identified for the expansion force,which correspond to venting,internal short-circuiting,and thermal runaway.In particular,an abnormal expansion force signal can be detected at temperatures as low as 42.4°C,followed by battery thermal runaway in approximately 6.5 min.Moreover,reducing the preload force can improve the effectiveness of the early-warning method via the expansion force.Specifically,reducing the preload force from 6000 to 1000 N prolongs the warning time(i.e.,227 to 398 s)before thermal runaway is triggered.Based on the results,a notable expansion force early-warning method is proposed that can successfully enable early safety warning approximately 375 s ahead of battery thermal runaway and effectively prevent failure propagation with module validation.This study provides a practical reference for the development of timely and accurate early-warning strategies as well as guidance for the design of safer battery systems. 展开更多
关键词 Lithium-ion battery Thermal runaway Preload force Expansionforce Early warning Multidimensional signal
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Periodic signal extraction of GNSS height time series based on adaptive singular spectrum analysis
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作者 Chenfeng Li Peibing Yang +1 位作者 Tengxu Zhang Jiachun Guo 《Geodesy and Geodynamics》 EI CSCD 2024年第1期50-60,共11页
Singular spectrum analysis is widely used in geodetic time series analysis.However,when extracting time-varying periodic signals from a large number of Global Navigation Satellite System(GNSS)time series,the selection... Singular spectrum analysis is widely used in geodetic time series analysis.However,when extracting time-varying periodic signals from a large number of Global Navigation Satellite System(GNSS)time series,the selection of appropriate embedding window size and principal components makes this method cumbersome and inefficient.To improve the efficiency and accuracy of singular spectrum analysis,this paper proposes an adaptive singular spectrum analysis method by combining spectrum analysis with a new trace matrix.The running time and correlation analysis indicate that the proposed method can adaptively set the embedding window size to extract the time-varying periodic signals from GNSS time series,and the extraction efficiency of a single time series is six times that of singular spectrum analysis.The method is also accurate and more suitable for time-varying periodic signal analysis of global GNSS sites. 展开更多
关键词 GNSS Time series Singular spectrum analysis Trace matrix Periodic signal
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Sounding the alarm:Functionally referential signaling in Azure-winged Magpie
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作者 Xingyi Jiang Yanyun Zhang 《Avian Research》 SCIE CSCD 2024年第1期35-41,共7页
Functionally referential signals are a complex form of communication that conveys information about the external environment.Such signals have been found in a range of mammal and bird species and have helped us unders... Functionally referential signals are a complex form of communication that conveys information about the external environment.Such signals have been found in a range of mammal and bird species and have helped us understand the complexities of animal communication.Corvids are well known for their extraordinary cognitive abilities,but relatively little attention has been paid to their vocal function.Here,we investigated the functionally referential signals of a cooperatively breeding corvid species,Azure-winged Magpie(Cyanopica cyanus).Through field observations,we suggest that Azure-winged Magpie uses referential alarm calls to distinguish two types of threats:’rasp’ calls for terrestrial threats and ’chatter’ calls for aerial threats.A playback experiment revealed that Azure-winged Magpies responded to the two call types with qualitatively different behaviors.They sought cover by flying into the bushes in response to the ’chatter’ calls,and flew to or stayed at higher positions in response to ’rasp’ calls,displaying a shorter response time to ’chatter’ calls.Significant differences in acoustic structure were found between the two types of calls.Given the extensive cognitive abilities of corvids and the fact that referential signals were once thought to be unique to primates,these findings are important for expanding our understanding of social communication and language evolution. 展开更多
关键词 Alarm call Animal communication Azure-winged Magpie Referential signal
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