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Set-Membership Filtering Approach to Dynamic Event-Triggered Fault Estimation for a Class of Nonlinear Time-Varying Complex Networks

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 638-648页

作者： Xiaoting Du Lei Zou Maiying Zhong the college of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266590China IEEE the college of information Science and technology Donghua UniversityShanghai 201620 the Engineering Research Center of Digitalized Textile and Fashion technology Ministry of EducationShanghai 201620China

The present study addresses the problem of fault estimation for a specific class of nonlinear time-varying complex networks,utilizing an unknown-input-observer approach within the framework of dynamic event-triggered mechanism(DETM).In order to optimize communication resource utilization,the DETM is employed to determine whether the current measurement data should be transmitted to the estimator or not.To guarantee a satisfactory estimation performance for the fault signal,an unknown-input-observer-based estimator is constructed to decouple the estimation error dynamics from the influence of fault signals.The aim of this paper is to find the suitable estimator parameters under the effects of DETM such that both the state estimates and fault estimates are confined within two sets of closed ellipsoid domains.The techniques of recursive matrix inequality are applied to derive sufficient conditions for the existence of the desired estimator,ensuring that the specified performance requirements are met under certain conditions.Then,the estimator gains are derived by minimizing the ellipsoid domain in the sense of trace and a recursive estimator parameter design algorithm is then provided.Finally,a numerical example is conducted to demonstrate the effectiveness of the designed estimator.

关键词： Dynamic event-triggered mechanism(DETM) fault estimation nonlinear time-varying complex networks set-member-ship filtering unknown input observer

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Vibronic effect study of ^(1)A_(2) state of H_(2)O and D_(2)O

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Chinese physics B 2024年第5期33卷 395-399页

作者：张倍源王礼涵朱剑辉徐卫青马子茹赵小利吴勇朱林繁 Department of Modern physics University of Science and Technology of ChinaHefei 230026China Center for Transformative Science ShanghaiTech UniversityShanghai 201210China Department of physics Yantai UniversityYantai 264005China Institute of Applied physics and Computational Mathematics Beijing 100088China School of physics and information technology Shaanxi Normal UniversityXi'an 710119China HEDPS Center for Applied Physics and TechnologyPeking UniversityBeijing 100084China

The generalized oscillator strengths of the dipole-forbidden excitations of the ^(1)A_(2) of H_(2)O and D_(2)O were calculated with the time dependent density functional theory,by taking into account the vibronic effect.It is found that the vibronic effect converts the dipole-forbidden excitation of the ^(1)A_(2) into a dipole-allowed one,which enhances the intensities of the corresponding generalized oscillator strength in the small squared momentum transfer region.The present investigation shows that the vibronic effect of H_(2)O is slightly stronger than that of D_(2)O,which exhibits a clear isotopic effect.

关键词： water heavy water generalized oscillator strength vibronic effect isotope effect

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Capturability-based Fuzzy Footstep Planner for a Biped Robot with Centroidal Compliance

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Journal of Bionic Engineering 2024年第1期21卷 84-100页

作者： Zihan Xu Qin Fang Yong Ren Chengju Liu Robot and Artificial Intelligence Lab(RAIL) College of Electronic and Information EngineeringTongji UniversityShanghai 201804China Applied technology college Soochow UniversitySuzhou 215000China

Compliance motion and footstep adjustment are active balance control strategies from learning human subconscious behaviors.The force estimation without direct end-actuator force measurement and the optimal footsteps based on complex analytical calculation are still challenging tasks for elementary and kid-size position-controlled robots.In this paper,an online compliant controller with Gravity Projection Observer(GPO),which can express the external force condition of perturbations by the estimated Projection of Gravity(PoG)with estimation covariance,is proposed for the realization of disturbance absorption,with which the robustness of the humanoid contact with environments can be maintained.The fuzzy footstep planner based on capturability analysis is proposed,and the Model Predictive Control(MPC)is applied to generate the desired steps.The fuzzification rules are well-designed and give the corresponding control output responding to complex and changeable external disturbances.To validate the presented methods,a series of experiments on a real humanoid robot are conducted.The results verify the effectiveness of the proposed balance control framework.

关键词： Biped walking Centroidal compliance Gravity projection observer Fuzzy footstep planner

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Ground state of Rydberg-dressed Bose gas confined in a toroidal trap

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Communications in Theoretical physics 2024年第1期76卷 29-35页

作者： Lin-Xue Wang Hong-Li Yang Hui Liu Si-Lin Chen Ya-Jun Wang Xiao-Fei Zhang Department of physics School of Physics and Information ScienceShaanxi University of Science and TechnologyXi'an 710021China Department of Basic Sciences Air Force Engineering UniversityXi'an 710051China

The experimental realization of Rydberg dressing technology in ultracold atomic systems provides another superior platform for studying novel states of matter and macroscopic quantum phenomena.In this work,based on the mean-field theory,we have investigated the ground-state phases of a two-component Bose–Einstein condensate with Rydberg interaction and confined in a toroidal trap.The effects of the Rydberg interaction and external potential,especially the Rydberg blockade radius,on the ground-state structure of such a system have been investigated in full parameter space.Our results show that the Rydberg blockade radius,which can be regarded as another controllable parameter,can be used to obtain a variety of ground-state phases.More interestingly,it is found that for weak Rydberg interactions,the Rydberg blockade radius breaks the spontaneous rotational symmetry of the system,leading to the formation of a discrete unit cell structure.For strongly interacting cases,it can be used to realize different orders of discrete rotational symmetry breaking.

关键词： Bose-Einstein condensate Rydberg dressing toroidal trap

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Towards understanding bogus traffic service in online social networks

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Frontiers of information technology & Electronic Engineering 2024年第3期25卷 415-431页

作者： Ping HE Xuhong ZHANG Changting LIN Ting WANG Shouling JI college of Computer Science and technology Zhejiang UniversityHangzhou 310027China Binjiang Institute of Zhejiang University Hangzhou 310027China college of information Sciences and technology Pennsylvania State UniversityUniversity Park 17057-4846USA

Critical functionality and huge infuence of the hot trend/topic page(HTP)in microblogging sites have driven the creation of a new kind of underground service called the bogus traffic service(BTS).BTS provides a kind of illegal service which hijacks the HTP by pushing the controlled topics into it for malicious customers with the goal of guiding public opinions.To hijack HTP,the agents of BTS maintain an army of black-market accounts called bogus trafic accounts(BTAs)and control BTAs to generate a burst of fake trafic by massively retweeting the tweets containing the customer desired topic(hashtag).Although this service has been extensively exploited by malicious customers,little has been done to understand it.In this paper,we conduct a systematic measurement study of the BTS.We first investigate and collect 125 BTS agents from a variety of sources and set up a honey pot account to capture BTAs from these agents.We then build a BTA detector that detects 162218 BTAs from Weibo,the largest Chinese microblogging site,with a precision of 94.5%.We further use them as a bridge to uncover 296916 topics that might be involved in bogus trafic.Finally,we uncover the operating mechanism from the perspectives of the attack cycle and the attack entity.The highlights of our findings include the temporal attack patterns and intelligent evasion tactics of the BTAs.These findings bring BTS into the spotlight.Our work will help in understanding and ultimately eliminating this threat.

关键词： Online social networks Measurement Bogus traffic Black market

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Recursive Filtering for Stochastic Systems With Filter-and-Forward Successive Relays

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1202-1212页

作者： Hailong Tan Bo Shen Qi Li Hongjian Liu School of Mathematics-physics and Finance Anhui Polytechnic UniversityWuhu 241000China Anhui Future technology Research Institute Anhui Polytechnic UniversityWuhu 241000China college of information Science and technology Donghua UniversityShanghai 201620China Engineering Research Center of Digitalized Textile and Fashion technology Ministry of EducationShanghai 201620China School of information Science and Engineering Hangzhou Normal UniversityHangzhou 311121China

In this paper,the recursive filtering problem is considered for stochastic systems over filter-and-forward successive relay(FFSR)networks.An FFSR is located between the sensor and the remote filter to forward the measurement.In the successive relay,two cooperative relay nodes are adopted to forward the signals alternatively,thereby existing switching characteristics and inter-relay interferences(IRI).Since the filter-and-forward scheme is employed,the signal received by the relay is retransmitted after it passes through a linear filter.The objective of the paper is to concurrently design optimal recursive filters for FFSR and stochastic systems against switching characteristics and IRI of relays.First,a uniform measurement model is proposed by analyzing the transmission mechanism of FFSR.Then,novel filter structures with switching parameters are constructed for both FFSR and stochastic systems.With the help of the inductive method,filtering error covariances are presented in the form of coupled difference equations.Next,the desired filter gain matrices are further obtained by minimizing the trace of filtering error covariances.Moreover,the stability performance of the filtering algorithm is analyzed where the uniform bound is guaranteed on the filtering error covariance.Finally,the effectiveness of the proposed filtering method over FFSR is verified by a three-order resistance-inductance-capacitance circuit system.

关键词： filtering successive stochastic

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Random Raman Fiber Laser as a Liquid Refractive Index Sensor

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Photonic Sensors 2024年第1期14卷 13-22页

作者： Bing HAN Yuxi MA Han WU Yong ZHAO college of information Science and Engineering Northeastern UniversityShenyang 110819China Hebei Key Laboratory of Micro-Nano Precision Optical Sensing and Measurement technology Qinhuangdao 066004China college of Electronics and information Engineering Sichuan UniversityChengdu 610064China

In this paper,a new concept of forward-pumped random Raman fiber laser(RRFL)-based liquid refractive index sensing is proposed for the first time.For liquid refractive index sensing,the flat fiber end immersed in the liquid can act as the point reflector for generating random fiber lasing and also as the sensing head.Due to the high sensitivity of the output power of the RRFL to the reflectivity provided by the point reflector in the ultralow reflectivity regime,the proposed RRFL is capable of achieving liquid refractive index sensing by measuring the random lasing output power.We theoretically investigate the effects of the operating pump power and fiber length on the refractive index sensitivity for the proposed RRFL.As a proof-of-concept demonstration,we experimentally realize high-sensitivity half-open short-cavity RRFL-based liquid refractive index sensing with the maximum sensitivity and the sensing resolution of-39.88W/RIU and 2.5075×10^(-5) RIU,respectively.We also experimentally verify that the refractive index sensitivity can be enhanced with the shorter fiber length of the RRFL.This work extends the application of the random fiber laser as a new platform for highly-sensitive refractive index sensing in chemical,biomedical,and environmental monitoring applications,etc.

关键词： Fiber optic sensors refractive index measurements fiber lasers Rayleigh scattering stimulated Raman scattering

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Algorithms and statistical analysis for linear structured weighted total least squares problem

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Geodesy and Geodynamics 2024年第2期15卷 177-188页

作者： Jian Xie Tianwei Qiu Cui Zhou Dongfang Lin Sichun Long School of Earth Science and Spatial information Engineering Hunan University of Science and TechnologyXiangtan 411201China college of Science Central South University of Forestry and TechnologyChangsha 410018China National-Local Joint Engineering Laboratory of Geo-spatial information technology Hunan University of Science and TechnologyXiangtan 411201China

Weighted total least squares(WTLS)have been regarded as the standard tool for the errors-in-variables(EIV)model in which all the elements in the observation vector and the coefficient matrix are contaminated with random errors.However,in many geodetic applications,some elements are error-free and some random observations appear repeatedly in different positions in the augmented coefficient matrix.It is called the linear structured EIV(LSEIV)model.Two kinds of methods are proposed for the LSEIV model from functional and stochastic modifications.On the one hand,the functional part of the LSEIV model is modified into the errors-in-observations(EIO)model.On the other hand,the stochastic model is modified by applying the Moore-Penrose inverse of the cofactor matrix.The algorithms are derived through the Lagrange multipliers method and linear approximation.The estimation principles and iterative formula of the parameters are proven to be consistent.The first-order approximate variance-covariance matrix(VCM)of the parameters is also derived.A numerical example is given to compare the performances of our proposed three algorithms with the STLS approach.Afterwards,the least squares(LS),total least squares(TLS)and linear structured weighted total least squares(LSWTLS)solutions are compared and the accuracy evaluation formula is proven to be feasible and effective.Finally,the LSWTLS is applied to the field of deformation analysis,which yields a better result than the traditional LS and TLS estimations.

关键词： Linear structured weighted total least squares Errors-in-variables Errors-in-observations Functional modelmodification Stochastic model modification Accuracyevaluation

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Radiation build-up and dissipation in Raman random fiber laser

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Science China(information Sciences) 2024年第1期67卷 254-260页

作者： Shengtao LIN Zinan WANG Jiaojiao ZHANG Pan WANG Han WU Yifei QI Key Laboratory of Optical Fiber Sensing and Communications University of Electronic Science and Technology of China college of Electronics and information Engineering Sichuan University

Raman random fiber laser(RRFL) is a complex physical system that arises from the distributed Raman amplification and the intrinsic stochasticity of fiber scattering.The analysis of the underlying lightwave kinetics at steady state has been the focus of considerable interest.However,the transient state,such as the RRFL build-up and dissipation,is particularly important for revealing the lightwave interaction process.Here,we investigate for the first time the RRFL dynamics at the transient state and track the RRFL temporal and spectral evolution theoretically and experimentally.Particularly,with the contribution of random distributed feedback,RRFL build-up exhibits continuous Verhulst logistic growth curves without cavity-related features,which is significantly different from the step-like growth curve of conventional fiber lasers.Furthermore,the radiation build-up duration is inversely related to the pump power,and the spectral evolution of the RRFL undergoes two phases,i.e.,from spectral density increase to spectral broadening.From the steady state to the pump switch-off state,the RRFL output power dissipates immediately,and the remaining Stokes lightwave from the Rayleigh scattering will gradually disappear after one round trip.This work provides new insights into the transient dynamic features of the RRFL.

关键词： random fiber laser stimulated Raman scattering transient phenomenon nonlinear optics łinebreak biological growth dynamics

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Two-dimensional investigation of characteristic parameters and their gradients for the self-generated electric and magnetic fields of laser-induced zirconium plasma

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Plasma Science and technology 2024年第5期26卷 138-155页

作者： Tayyaba SAJID Shazia BASHIR Mahreen AKRAM Maira RAZZAQ Khaliq MAHMOOD Centre for Advanced Studies in physics Institute of PhysicsGovernment College University LahoreLahore 54000Pakistan Department of physics Institute of PhysicsGovernment College University LahoreLahore 54000Pakistan

Two-dimensional diagnosis of laser-induced zirconium(Zr)plasma has been experimentally performed using the time-of-flight method by employing Faraday cups in addition to electric and magnetic probes.The characteristic parameters of laser-induced Zr plasma have been evaluated as a function of different laser irradiances ranging from 4.5 to 11.7 GW cm-2 at different axial positions of 1–4 cm with a fixed radial distance of 2 cm.A well-supporting correlation between the plume parameters and the laser-plasma-produced spontaneous electric and magnetic(E and B)fields was established.The measurements of the characteristic parameters and spontaneously induced fields were observed to have an increasing trend with the increasing laser irradiance.However,when increasing the spatial distance in both the axial and radial directions,the plasma parameters(electron/ion number density,temperature and kinetic energy)did not show either continuously increasing or decreasing trends due to various kinetic and dynamic processes during the spatial evolution of the plume.However,the E and B fields were observed to be always diffusing away from the target.The radial component of electron number densities remained higher than the axial number density component,whereas the axial ion number density at all laser irradiances and axial distances remained higher than the radial ion number density.The higher axial self-generated electric field(SGEF)values than radial SGEF values are correlated with the effective charge-separation mechanism of electrons and ions.The generation of a self-generated magnetic field is observed dominantly in the radial direction at increasing laser irradiance as compared to the axial one due to the deflection of fast-moving electrons and the persistence of two-electron temperature on the radial axis.

关键词： Faraday cup axial and radial expansion space-charge effect laser-induced zirconium plasma two-electron temperature distribution self-generated electric and magnetic fields

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