The dynamic characteristics of the track system can directly affect its service performance and failure process.To explore the load characteristics and dynamic response of the track system under the dynamic loads from...The dynamic characteristics of the track system can directly affect its service performance and failure process.To explore the load characteristics and dynamic response of the track system under the dynamic loads from the rack vehicle in traction conditions,a systematic test of the track subsystem was carried out on a large-slope test line.In the test,the bending stress of the rack teeth,the wheel-rail forces,and the acceleration of crucial components in the track system were measured.Subsequently,a detailed analysis was conducted on the tested signals of the rack railway track system in the time domain and the time-frequency domains.The test results indicate that the traction force significantly affects the rack tooth bending stress and the wheel-rail forces.The vibrations of the track system under the traction conditions are mainly caused by the impacts generated from the gear-rack engagement,which are then transferred to the sleepers,the rails,and the ballast beds.Furthermore,both the maximum stress on the racks and the wheel-rail forces measured on the rails remain below their allowable values.This experimental study evaluates the load characteristics and reveals the vibration characteristics of the rack railway track system under the vehicle’s ultimate load,which is very important for the load-strengthening design of the key components such as racks and the vibration and noise reduction of the track system.展开更多
This paper presents an ultralow-frequency cyclic loading creep test system for rock salt.The system comprises five subsystems:a cyclic load generation system,a triaxial pressure chamber,a pressure and deformation moni...This paper presents an ultralow-frequency cyclic loading creep test system for rock salt.The system comprises five subsystems:a cyclic load generation system,a triaxial pressure chamber,a pressure and deformation monitoring system,a signal acquisition and load control integrated system,and an automatic oil replenishment and discharge system.This test system overcomes the limitations of traditional electrohydraulic servo creep testing machines and gravity loading creep testing machines when conducting low-frequency cyclic load creep tests.This allows for long-term(1-2 years)creep tests under extremely-low-frequency cyclic loading conditions,which simulate the actual operating conditions of salt cavern gas storage.The cyclic load generation system converted constant-weight loads into a continuously variable hydraulic oil pressure and amplified the oil pressure using a pressure intensifier,which provided a stable load source for the test system.Using this test system,creep tests were performed under low-frequency cyclic loading with periods of 1 d and 7 d.The results showed that the test system performed well,as evidenced by the validation of the loading capacity,loading stability,and temperature control stability.Comparing the creep deformation of rock salt samples with the cyclic periods of 1 d and 7 d,it was observed that,within this cyclic period range,the creep deformation of the sample increased with higher loading frequencies,provided that the cyclic loading waveform and stress remained constant.展开更多
Considering the challenges posed by external disturbances on carrier-based aircraft land-ing control,higher demands are required for the precision and convergence of the carrier landingcontrol system.First,this paper ...Considering the challenges posed by external disturbances on carrier-based aircraft land-ing control,higher demands are required for the precision and convergence of the carrier landingcontrol system.First,this paper proposes an Adaptive Terminal Sliding Combined Super TwistingControl(ATS-STC)method to address the issues of low precision,slow convergence,and poor dis-turbance rejection capability resulting from external disturbances,such as carrier air-wake and deckmotion.By introducing a nonlinear term into the sliding surface and employing an integralapproach,the proposed ATS-STC method can ensure finite-time convergence and mitigate the chat-tering problem.An adaptive law is also utilized to estimate the external disturbances,therebyenhancing the anti-disturbance performance.Then,the stability and convergence time analysis ofthe designed controller are conducted.Based on the proposed method,an Automatic Carrier Land-ing System(ACLS)is developed to perform the carrier landing control task.Furthermore,a multi-dimensional validation is carried out.For the numerical simulation test,the Terminal Sliding ModeControl(TSMC)method and Proportion Integration Differentiation(PID)method are introducedas comparison,the quantitative assessment results show that the tracking error of TSMC and PIDcan reach 1.5 times and 2 times that of the proposed method.Finally,the Hardware-in-the-Loop(HIL)test and real flight test are conducted.All the experimental results demonstrate that the pro-posed control method is more effective and precise.展开更多
The pressure-preserving controller is the key component of deep in situ pressure-preserving coring(IPP-Coring).With increasing drilling depth,the environmental temperature and pressure increase accordingly.However,due...The pressure-preserving controller is the key component of deep in situ pressure-preserving coring(IPP-Coring).With increasing drilling depth,the environmental temperature and pressure increase accordingly.However,due to the strength and sealing problems of pressure-preserving controllers,the coring pressure is generally lower than 70 MPa.Establishing a high-temperature and ultrahigh-pressure test system is highly important for improving the strength and sealing performance of pressure-preserving controllers.This paper introduces a high-temperature and ultrahigh-pressure test system for deep IPP-Coring controller performance analysis.The device includes six parts:an auxiliary air source system,a pressurization system,a temperature control system,a hydraulic system,a data acquisition and electrical control system,and an ultrahigh-pressure vessel.The test system can reconstruct a 150℃ and 200 MPa in situ environment and simulate and test the movement state of the corer and the stability of the pressure-preserving action trigger of the pressure-preserving controller in the deep IPP-Coring process.To verify the performance of this test system,saddle-shaped pressure-preserving controllers made of four different materials were subjected to pressure tests under normal-temperature and high-temperature conditions.The results showed that the ultimate pressure-bearing capability of the pressure-preserving controller greatly varied between normal-temperature and high-temperature conditions.The pressure-preserving ability and sealing performance of the pressure-preserving controller decreased significantly at high temperature,and the pressure-preserving controller exhibited significantly different sealing failure characteristics due to material differences.This study is important for progressing the extraction and evaluation of deep reservoir resources.展开更多
Based on the analysis and research of the airworthiness objective of integrated modular avionics system(IMA),and the characteristics of IMA system’s comprehensive and complex cross-linking with other airborne systems...Based on the analysis and research of the airworthiness objective of integrated modular avionics system(IMA),and the characteristics of IMA system’s comprehensive and complex cross-linking with other airborne systems,the extraction strategy of IMA system’s compliance flight test subjects and the selection method of IMA system’s compliance flight test parameters are proposed.The data analysis method based on the abnormal probability matrix of the IMA system is proposed for the first time,and the abnormal state information of the IMA system can be quickly identified.The compliance flight test of the IMA system is completed with limited flight test resources,which achieves the purpose of saving flight test sorties and improving flight test efficiency.This research has been successfully applied to the airworthiness certification flight test of a certain civil transport aircraft in China,and can provide technical support for the subsequent type flight test.展开更多
AIM:To measure the optimal anterior chamber pressure(ACP)for safe phacoemulsification using a new tube chamber system with internal pressure measurement function in the porcine eye.METHODS:The 20-gauge and 21-gauge st...AIM:To measure the optimal anterior chamber pressure(ACP)for safe phacoemulsification using a new tube chamber system with internal pressure measurement function in the porcine eye.METHODS:The 20-gauge and 21-gauge straight tips with yellow and orange sleeves,respectively,were covered by a test chamber combined with a pressure sensor for measuring ACP.This was measured for 20s from 10s after starting aspiration in the linear mode using vacuum levels of 200 and 150 mm Hg with a 20-gauge tip,and 300 and 250 mm Hg with a 21-gauge tip.Using a porcine eye,a pressure sensor fixed with a 0.9 mm corneal incision measured ACP.For the posterior capsule contact assay,porcine eyes were treated as described above,and the ultrasonic needle tip was held at the height of the iris and aspirated for 30s in linear mode at a vacuum of 200 and 150 mm Hg for the 20-gauge tip,and 300 and 250 mm Hg for the 21-gauge tip.The bottle height at which the posterior capsule accidentally contacted the ultrasonic tip was recorded,and the estimated ACP was calculated.RESULTS:The internal pressure of the new tube chamber system and ACP from the porcine eye closely matched proportional changes at vacuum levels of 200 and 150 mm Hg with 20-gauge tips.Similarly,proportional changes at vacuum levels of 300 and 250 mm Hg with the 21-gauge tip were nearly equal.The bottle height at which the posterior capsule contacted with the tip and estimated ACP were 57.5±12.6 cm(20.2±7.9 mm Hg)at 200 mm Hg with a 20-gauge tip,35.0±10.0 cm(16.6±6.3 mm Hg)at 150 mm Hg with a 20-gauge tip,47.5±12.6 cm(18.7±8.7 mm Hg)at 300 mm Hg with a 21-gauge tip,and 32.5±5.0 cm(15.7±3.5 mm Hg)at 250 mm Hg with a 21-gauge tip.CONCLUSION:A comprehensive understanding of this chamber system’s characteristics and usage can resolve anterior chamber instability caused by changing preoperative settings on the phaco machine.展开更多
Published proof test coverage(PTC)estimates for emergency shutdown valves(ESDVs)show only moderate agreement and are predominantly opinion-based.A Failure Modes,Effects,and Diagnostics Analysis(FMEDA)was undertaken us...Published proof test coverage(PTC)estimates for emergency shutdown valves(ESDVs)show only moderate agreement and are predominantly opinion-based.A Failure Modes,Effects,and Diagnostics Analysis(FMEDA)was undertaken using component failure rate data to predict PTC for a full stroke test and a partial stroke test.Given the subjective and uncertain aspects of the FMEDA approach,specifically the selection of component failure rates and the determination of the probability of detecting failure modes,a Fuzzy Inference System(FIS)was proposed to manage the data,addressing the inherent uncertainties.Fuzzy inference systems have been used previously for various FMEA type assessments,but this is the first time an FIS has been employed for use with FMEDA.ESDV PTC values were generated from both the standard FMEDA and the fuzzy-FMEDA approaches using data provided by FMEDA experts.This work demonstrates that fuzzy inference systems can address the subjectivity inherent in FMEDA data,enabling reliable estimates of ESDV proof test coverage for both full and partial stroke tests.This facilitates optimized maintenance planning while ensuring safety is not compromised.展开更多
To obtain the certificate of airworthiness,it is essential to conduct a full-scale aircraft static test.During such test,accurate and comprehensive wing deformation measurement is crucial for assessing its strength,st...To obtain the certificate of airworthiness,it is essential to conduct a full-scale aircraft static test.During such test,accurate and comprehensive wing deformation measurement is crucial for assessing its strength,stiffness,and bearing capability.This paper proposes a novel and cost-effective videogrammetric method using multi-camera system to achieve the non-contact,highprecision,and 3D measurement of overall static deformation for the large-scale wing structure.To overcome the difficulties of making,carrying,and employing the large 2D or 3D target for calibrating the cameras with large field of view,a flexible stereo cameras calibration method combining 1D target and epipolar geometry is proposed.The global calibration method,aided by a total station,is employed to unify the 3D data obtained from various binocular subsystems.A series of static load tests using a 10-meter-long large-scale wing have been conducted to validate the proposed system and methods.Furthermore,the proposed method was applied to the practical wing deformation measurement of both wings with a wingspan of 33.6 m in the full-size civil aircraft static test.The overall 3D profile and displacement data of the tested wing under various loads can be accurately obtained.The maximum error of distance and displacement measurement is less than 4.5 mm within the measurement range of 35 m in all load cases.These results demonstrate that the proposed method achieves effective,high-accuracy,on-site,and visualized wing deformation measurement,making it a promising approach for full-scale aircraft wing static test.展开更多
Aeropropulsion System Test Facility (ASTF) is required to accurately control the pressure and temperature of the airflow to test the performance of the aero-engine. However, the control accuracy of ASTF is significant...Aeropropulsion System Test Facility (ASTF) is required to accurately control the pressure and temperature of the airflow to test the performance of the aero-engine. However, the control accuracy of ASTF is significantly affected by the flow disturbance caused by aero-engine acceleration and deceleration. This would reduce the credibility of ASTF’s test results for the aero-engine. Therefore, first, this paper proposes a feedforward compensation-based L1 adaptive control method for ASTF to address this problem. The baseline controller is first designed based on ideal uncoupled closed-loop dynamics to achieve dynamic decoupling. Then, L1 adaptive control is adopted to deal with various uncertainties and ensure good control performance. To further enhance the anti-disturbance performance, a feedforward strategy based on disturbance prediction is designed in the L1 adaptive control framework to compensate for the unmatched flow disturbance, which cannot be measured directly. In addition, this strategy takes into account the effects of actuator dynamics. With this method, the feedforward term can be determined from the nominal model parameters despite uncertainties. Finally, to demonstrate the effectiveness of the proposed method, various comparative experiments are performed on a hardware-in-the-loop system of ASTF. The experimental results show that the proposed method possesses excellent tracking performance, anti-disturbance performance and robustness.展开更多
Transmission tower-line systems(TTLSs)play a crucial role in the long-distance transmission of electrical energy,often necessitating their crossing through active fault areas.However,previous studies have given limite...Transmission tower-line systems(TTLSs)play a crucial role in the long-distance transmission of electrical energy,often necessitating their crossing through active fault areas.However,previous studies have given limited attention to the seismic performance of fault-crossing transmission TTLSs,particularly in terms of considering the impact of permanent ground motion displacements(PGMDs).This study attempts to address this concern by evaluating the seismic performance of TTLSs exposed to fault earthquakes.Three strike-slip ground motions are carefully selected,and the corresponding PGMDs are accurately replicated through baseline adjustment.A meticulously designed and fabricated reduced-scale experimental model of a TTLS is then employed to investigate the influence of the fault crossing location(FCL)on its seismic performance.The shake table tests conducted unequivocally demonstrate that PGMDs significantly amplify the seismic responses of the TTLS and identify the most unfavorable FCL.Furthermore,a finite element model(FEM)is developed and its accuracy is validated by comparing it with the experimental results.Parametric analyses are conducted to explore the effects of fault crossing angles(FCAs)and PGMD amplitudes on the seismic performances of TTLSs.This study is expected to contribute valuable insights for the seismic design and performance analysis of TTLSs crossing fault areas.展开更多
This paper introduces a kind of substitute bench testing method for vehicle application development and testing method of the test requirements,including battery fast conversion cycle test equipment,enter type incubat...This paper introduces a kind of substitute bench testing method for vehicle application development and testing method of the test requirements,including battery fast conversion cycle test equipment,enter type incubator,liquid-cooled machine and ancillary equipment composed of a set of test system,through the walk-in constant temperature box to simulate the new energy vehicles under different environmental conditions of the test requirements,Liquid-cooled machine and auxiliary parts to complete the battery thermal management system need cooling fluid conditions,the battery conversion cycle test equipment to simulate the dc fast charging way of filling pile,complete battery thermal management system test,shorten the filling fast charging time and improve battery fast charge security,for troubleshooting and data collection and analysis,Improve work efficiency,save costs,and eliminate customer anxiety about battery life and charging time.展开更多
As the commercialization of the fifth gen-eration communication(5G)is sped up,its system testing scheme is vital for the successful deployment of 5G.Especially,5G relies on the scale-increased multiple-input-multiple ...As the commercialization of the fifth gen-eration communication(5G)is sped up,its system testing scheme is vital for the successful deployment of 5G.Especially,5G relies on the scale-increased multiple-input-multiple output(MIMO)technique to improve its capacity and coverage.Thus,testing new functions of the 5G MIMO system accurately and ef-ficiently,including beamforming(beam-tracking with movement)and multiple-user(MU)multiplexing,is a challenging task.This paper tries to construct a lab-oratorial hardware and conduct equipment-controlled field testing.Firstly,the testing scheme is presented,which is composed of the framework,the channel models and the validation methods.Then,the channel model principles are explained in detail due to its di-rect influence on the testing accuracy.Specifically,we utilize the spatial consistency and the multi-link cor-relation properties to emulate the high-speed dynamic time-varying(HDT)and the multiple-cell(MC)-MU-MIMO channels.Finally,the above testing scheme is verified in a Shanghai 5G field experiment with the practical commercial equipment and the channel em-ulator.The results show that the 5G new functions are tested accurately and efficiently by switching the channel emulation configurations.展开更多
Test case prioritization and ranking play a crucial role in software testing by improving fault detection efficiency and ensuring software reliability.While prioritization selects the most relevant test cases for opti...Test case prioritization and ranking play a crucial role in software testing by improving fault detection efficiency and ensuring software reliability.While prioritization selects the most relevant test cases for optimal coverage,ranking further refines their execution order to detect critical faults earlier.This study investigates machine learning techniques to enhance both prioritization and ranking,contributing to more effective and efficient testing processes.We first employ advanced feature engineering alongside ensemble models,including Gradient Boosted,Support Vector Machines,Random Forests,and Naive Bayes classifiers to optimize test case prioritization,achieving an accuracy score of 0.98847 and significantly improving the Average Percentage of Fault Detection(APFD).Subsequently,we introduce a deep Q-learning framework combined with a Genetic Algorithm(GA)to refine test case ranking within priority levels.This approach achieves a rank accuracy of 0.9172,demonstrating robust performance despite the increasing computational demands of specialized variation operators.Our findings highlight the effectiveness of stacked ensemble learning and reinforcement learning in optimizing test case prioritization and ranking.This integrated approach improves testing efficiency,reduces late-stage defects,and improves overall software stability.The study provides valuable information for AI-driven testing frameworks,paving the way for more intelligent and adaptive software quality assurance methodologies.展开更多
Members of the British Textile Machinery Association(BTMA)can look back on 2025 as a year marked by notable technological advances and continued progress in global trade,despite an uncertain and volatile market.“Our ...Members of the British Textile Machinery Association(BTMA)can look back on 2025 as a year marked by notable technological advances and continued progress in global trade,despite an uncertain and volatile market.“Our members have been very active over the past 12 months and this has resulted in new technologies for the production of technical fibres and fabrics,the introduction of AI and machine learning into process control systems and significant advances in materials testing,”says BTMA CEO Jason Kent.“There’s real excitement about what can be achieved in 2026 as we look ahead to upcoming exhibitions such as JEC Composites in Paris in March and Techtextil in Frankfurt in April.”展开更多
With the rapid development of artificial intelligence,the intelligence level of software is increasingly improving.Intelligent software,which is widely applied in crucial fields such as autonomous driving,intelligent ...With the rapid development of artificial intelligence,the intelligence level of software is increasingly improving.Intelligent software,which is widely applied in crucial fields such as autonomous driving,intelligent customer service,and medical diagnosis,is constructed based on complex technologies like machine learning and deep learning.Its uncertain behavior and data dependence pose unprecedented challenges to software testing.However,existing software testing courses mainly focus on conventional contents and are unable to meet the requirements of intelligent software testing.Therefore,this work deeply analyzed the relevant technologies of intelligent software testing,including reliability evaluation indicator system,neuron coverage,and test case generation.It also systematically designed an intelligent software testing course,covering teaching objectives,teaching content,teaching methods,and a teaching case.Verified by the practical teaching in four classes,this course has achieved remarkable results,providing practical experience for the reform of software testing courses.展开更多
Cloud services,favored by many enterprises due to their high flexibility and easy operation,are widely used for data storage and processing.However,the high latency,together with transmission overheads of the cloud ar...Cloud services,favored by many enterprises due to their high flexibility and easy operation,are widely used for data storage and processing.However,the high latency,together with transmission overheads of the cloud architecture,makes it difficult to quickly respond to the demands of IoT applications and local computation.To make up for these deficiencies in the cloud,fog computing has emerged as a critical role in the IoT applications.It decentralizes the computing power to various lower nodes close to data sources,so as to achieve the goal of low latency and distributed processing.With the data being frequently exchanged and shared between multiple nodes,it becomes a challenge to authorize data securely and efficiently while protecting user privacy.To address this challenge,proxy re-encryption(PRE)schemes provide a feasible way allowing an intermediary proxy node to re-encrypt ciphertext designated for different authorized data requesters without compromising any plaintext information.Since the proxy is viewed as a semi-trusted party,it should be taken to prevent malicious behaviors and reduce the risk of data leakage when implementing PRE schemes.This paper proposes a new fog-assisted identity-based PRE scheme supporting anonymous key generation,equality test,and user revocation to fulfill various IoT application requirements.Specifically,in a traditional identity-based public key architecture,the key escrow problem and the necessity of a secure channel are major security concerns.We utilize an anonymous key generation technique to solve these problems.The equality test functionality further enables a cloud server to inspect whether two candidate trapdoors contain an identical keyword.In particular,the proposed scheme realizes fine-grained user-level authorization while maintaining strong key confidentiality.To revoke an invalid user identity,we add a revocation list to the system flows to restrict access privileges without increasing additional computation cost.To ensure security,it is shown that our system meets the security notion of IND-PrID-CCA and OW-ID-CCA under the Decisional Bilinear Diffie-Hellman(DBDH)assumption.展开更多
Lateral flow immunoassays(LFIAs)are low-cost,rapid,and easy to use for pointof-care testing(POCT),but the majority of the available LFIA tests are indicative,rather than quantitative,and their sensitivity in antigen t...Lateral flow immunoassays(LFIAs)are low-cost,rapid,and easy to use for pointof-care testing(POCT),but the majority of the available LFIA tests are indicative,rather than quantitative,and their sensitivity in antigen tests are usually limited at the nanogram range,which is primarily due to the passive capillary fluidics through nitrocellulose membranes,often associated with non-specific bindings and high background noise.To overcome this challenge,we report a Beads-on-a-Tip design by replacing nitrocellulose membranes with a pipette tip loaded with magnetic beads.The beads are pre-conjugated with capture antibodies that support a typical sandwich immunoassay.This design enriches the low-abundant antigen proteins and allows an active washing process to significantly reduce non-specific bindings.To further improve the detection sensitivity,we employed upconversion nanoparticles(UCNPs)as luminescent reporters and SARS-CoV-2 spike(S)antigen as a model analyte to benchmark the performance of this design against our previously reported methods.We found that the key to enhance the immunocomplex formation and signal-to-noise ratio lay in optimizing incubation time and the UCNP-to-bead ratio.We therefore successfully demonstrated that the new method can achieve a very large dynamic range from 500 fg/mL to 10μg/mL,across over 7 digits,and a limit of detection of 706 fg/mL,nearly another order of magnitude lower than the best reported LFIA using UCNPs in COVID-19 spike antigen detection.Our system offers a promising solution for ultra-sensitive and quantitative POCT diagnostics.展开更多
Purpose: Normobaric hypoxia(NH) is a frequent strategy for training under hypoxic conditions that can be administered through different equipment, including face masks or hypoxic chambers/tents. Nonetheless, the versa...Purpose: Normobaric hypoxia(NH) is a frequent strategy for training under hypoxic conditions that can be administered through different equipment, including face masks or hypoxic chambers/tents. Nonetheless, the versatility of administration methods may influence the outcomes.Methods: Web of Science, Scopus, SPORTDiscus and Pub Med/MEDLINE were searched to identify studies assessing the effect of NH administered by face mask or chamber/tent equipment on maximal oxygen uptake( VO2max) after a training period. An overall meta-analysis and sub-analysis of total program session volume(low, moderate, high), participants' training level(trained, active, sedentary), and the severity of hypoxia(moderate, severe) were conducted to explore the effects of the NH-administration system.Results: Eighteen studies were included. Compared with normoxia, NH showed a moderate global improvement in VO2max(standardized mean difference [SMD] = 0.74;p = 0.06), favoring the chamber/tent(SMD = 1.30;p< 0.01) over the face mask. Sub-analysis showed a very large effect in support of the hypoxic chamber/tent among sedentary individuals and training programs with a high volume of sessions. Severe hypoxia did not yield conclusive findings in VO2max improvements, although the chamber/tent proved more effective(SMD = 1.42;p< 0.01) than the face mask under moderate hypoxia.Conclusions: Chambers/tents may slightly accentuate the benefit of NH on aerobic performance, particularly in participants with limited training experience following a high volume of sessions under moderate hypoxia.However, the variability of sub-analysis factors(session volume, participants' training level, and methodological approaches) between studies using each type of hypoxia-generating equipment may influence this result.展开更多
The authors consider the issue of hypothesis testing in varying-coefficient regression models with high-dimensional data.Utilizing kernel smoothing techniques,the authors propose a locally concerned U-statistic method...The authors consider the issue of hypothesis testing in varying-coefficient regression models with high-dimensional data.Utilizing kernel smoothing techniques,the authors propose a locally concerned U-statistic method to assess the overall significance of the coefficients.The authors establish that the proposed test is asymptotically normal under both the null hypothesis and local alternatives.Based on the locally concerned U-statistic,the authors further develop a globally concerned U-statistic to test whether the coefficient function is zero.A stochastic perturbation method is employed to approximate the distribution of the globally concerned test statistic.Monte Carlo simulations demonstrate the validity of the proposed test in finite samples.展开更多
Smartphone-based electrocardiograms(ECGs)are increasingly utilized for monitoring atrial fibrillation(AF)recurrence after catheter ablation(CA),referred to as smartphone AF burden(SMURDEN).The SMURDEN data often exhib...Smartphone-based electrocardiograms(ECGs)are increasingly utilized for monitoring atrial fibrillation(AF)recurrence after catheter ablation(CA),referred to as smartphone AF burden(SMURDEN).The SMURDEN data often exhibit complex patterns of zero AF episodes,which may arise from either true AF-free status(structural zeros)or missed AF episodes due to intermittent monitoring(random zeros).Such a mixture of AF-free and at-risk patients can lead to zero-inflation in the data.The authors propose a novel zero-inflation test for binomial regression models to identify recurrence-free AF populations.Unlike traditional approaches requiring fully specified zero-inflated models,the proposed test utilizes a weighted average of the discrepancies between observed and expected zero proportions,with weights determined by binomial sizes.A closed-form test statistic is developed,and its asymptotic distribution is derived using estimating equations.Simulations demonstrate superior performance over existing methods,and real-world AF monitoring data validate the practical utility of our proposed test.展开更多
基金supported by the National Natural Science Foundation of China(No.52388102)the Sichuan Science and Technology Program(No.2024NSFTD0011)the Fundamental Research Funds for the State Key Laboratory of Rail Transit Vehicle System of Southwest Jiaotong University(No.2023TPL-T11).
文摘The dynamic characteristics of the track system can directly affect its service performance and failure process.To explore the load characteristics and dynamic response of the track system under the dynamic loads from the rack vehicle in traction conditions,a systematic test of the track subsystem was carried out on a large-slope test line.In the test,the bending stress of the rack teeth,the wheel-rail forces,and the acceleration of crucial components in the track system were measured.Subsequently,a detailed analysis was conducted on the tested signals of the rack railway track system in the time domain and the time-frequency domains.The test results indicate that the traction force significantly affects the rack tooth bending stress and the wheel-rail forces.The vibrations of the track system under the traction conditions are mainly caused by the impacts generated from the gear-rack engagement,which are then transferred to the sleepers,the rails,and the ballast beds.Furthermore,both the maximum stress on the racks and the wheel-rail forces measured on the rails remain below their allowable values.This experimental study evaluates the load characteristics and reveals the vibration characteristics of the rack railway track system under the vehicle’s ultimate load,which is very important for the load-strengthening design of the key components such as racks and the vibration and noise reduction of the track system.
基金funding support from the General Program of the National Natural Science Foundation of China(Grant No.52374069)the Excellent Young Scientists Fund Program of the National Natural Science Foundation of China(Grant No.52122403)the Youth Innovation Promotion Association CAS(Grant No.Y2023089).
文摘This paper presents an ultralow-frequency cyclic loading creep test system for rock salt.The system comprises five subsystems:a cyclic load generation system,a triaxial pressure chamber,a pressure and deformation monitoring system,a signal acquisition and load control integrated system,and an automatic oil replenishment and discharge system.This test system overcomes the limitations of traditional electrohydraulic servo creep testing machines and gravity loading creep testing machines when conducting low-frequency cyclic load creep tests.This allows for long-term(1-2 years)creep tests under extremely-low-frequency cyclic loading conditions,which simulate the actual operating conditions of salt cavern gas storage.The cyclic load generation system converted constant-weight loads into a continuously variable hydraulic oil pressure and amplified the oil pressure using a pressure intensifier,which provided a stable load source for the test system.Using this test system,creep tests were performed under low-frequency cyclic loading with periods of 1 d and 7 d.The results showed that the test system performed well,as evidenced by the validation of the loading capacity,loading stability,and temperature control stability.Comparing the creep deformation of rock salt samples with the cyclic periods of 1 d and 7 d,it was observed that,within this cyclic period range,the creep deformation of the sample increased with higher loading frequencies,provided that the cyclic loading waveform and stress remained constant.
基金supported by the National Natural Science Foundation of China(No.T2288101)the National Key Research and Development Project,China(No.2020YFC1512500)the Academic Excellence Foundation of Beijing University of Aeronautics and Astronautics(BUAA)。
文摘Considering the challenges posed by external disturbances on carrier-based aircraft land-ing control,higher demands are required for the precision and convergence of the carrier landingcontrol system.First,this paper proposes an Adaptive Terminal Sliding Combined Super TwistingControl(ATS-STC)method to address the issues of low precision,slow convergence,and poor dis-turbance rejection capability resulting from external disturbances,such as carrier air-wake and deckmotion.By introducing a nonlinear term into the sliding surface and employing an integralapproach,the proposed ATS-STC method can ensure finite-time convergence and mitigate the chat-tering problem.An adaptive law is also utilized to estimate the external disturbances,therebyenhancing the anti-disturbance performance.Then,the stability and convergence time analysis ofthe designed controller are conducted.Based on the proposed method,an Automatic Carrier Land-ing System(ACLS)is developed to perform the carrier landing control task.Furthermore,a multi-dimensional validation is carried out.For the numerical simulation test,the Terminal Sliding ModeControl(TSMC)method and Proportion Integration Differentiation(PID)method are introducedas comparison,the quantitative assessment results show that the tracking error of TSMC and PIDcan reach 1.5 times and 2 times that of the proposed method.Finally,the Hardware-in-the-Loop(HIL)test and real flight test are conducted.All the experimental results demonstrate that the pro-posed control method is more effective and precise.
基金funding support from National Natural Science Foundation of China(Grant Nos.52225403,51827901,and 52304146).
文摘The pressure-preserving controller is the key component of deep in situ pressure-preserving coring(IPP-Coring).With increasing drilling depth,the environmental temperature and pressure increase accordingly.However,due to the strength and sealing problems of pressure-preserving controllers,the coring pressure is generally lower than 70 MPa.Establishing a high-temperature and ultrahigh-pressure test system is highly important for improving the strength and sealing performance of pressure-preserving controllers.This paper introduces a high-temperature and ultrahigh-pressure test system for deep IPP-Coring controller performance analysis.The device includes six parts:an auxiliary air source system,a pressurization system,a temperature control system,a hydraulic system,a data acquisition and electrical control system,and an ultrahigh-pressure vessel.The test system can reconstruct a 150℃ and 200 MPa in situ environment and simulate and test the movement state of the corer and the stability of the pressure-preserving action trigger of the pressure-preserving controller in the deep IPP-Coring process.To verify the performance of this test system,saddle-shaped pressure-preserving controllers made of four different materials were subjected to pressure tests under normal-temperature and high-temperature conditions.The results showed that the ultimate pressure-bearing capability of the pressure-preserving controller greatly varied between normal-temperature and high-temperature conditions.The pressure-preserving ability and sealing performance of the pressure-preserving controller decreased significantly at high temperature,and the pressure-preserving controller exhibited significantly different sealing failure characteristics due to material differences.This study is important for progressing the extraction and evaluation of deep reservoir resources.
文摘Based on the analysis and research of the airworthiness objective of integrated modular avionics system(IMA),and the characteristics of IMA system’s comprehensive and complex cross-linking with other airborne systems,the extraction strategy of IMA system’s compliance flight test subjects and the selection method of IMA system’s compliance flight test parameters are proposed.The data analysis method based on the abnormal probability matrix of the IMA system is proposed for the first time,and the abnormal state information of the IMA system can be quickly identified.The compliance flight test of the IMA system is completed with limited flight test resources,which achieves the purpose of saving flight test sorties and improving flight test efficiency.This research has been successfully applied to the airworthiness certification flight test of a certain civil transport aircraft in China,and can provide technical support for the subsequent type flight test.
文摘AIM:To measure the optimal anterior chamber pressure(ACP)for safe phacoemulsification using a new tube chamber system with internal pressure measurement function in the porcine eye.METHODS:The 20-gauge and 21-gauge straight tips with yellow and orange sleeves,respectively,were covered by a test chamber combined with a pressure sensor for measuring ACP.This was measured for 20s from 10s after starting aspiration in the linear mode using vacuum levels of 200 and 150 mm Hg with a 20-gauge tip,and 300 and 250 mm Hg with a 21-gauge tip.Using a porcine eye,a pressure sensor fixed with a 0.9 mm corneal incision measured ACP.For the posterior capsule contact assay,porcine eyes were treated as described above,and the ultrasonic needle tip was held at the height of the iris and aspirated for 30s in linear mode at a vacuum of 200 and 150 mm Hg for the 20-gauge tip,and 300 and 250 mm Hg for the 21-gauge tip.The bottle height at which the posterior capsule accidentally contacted the ultrasonic tip was recorded,and the estimated ACP was calculated.RESULTS:The internal pressure of the new tube chamber system and ACP from the porcine eye closely matched proportional changes at vacuum levels of 200 and 150 mm Hg with 20-gauge tips.Similarly,proportional changes at vacuum levels of 300 and 250 mm Hg with the 21-gauge tip were nearly equal.The bottle height at which the posterior capsule contacted with the tip and estimated ACP were 57.5±12.6 cm(20.2±7.9 mm Hg)at 200 mm Hg with a 20-gauge tip,35.0±10.0 cm(16.6±6.3 mm Hg)at 150 mm Hg with a 20-gauge tip,47.5±12.6 cm(18.7±8.7 mm Hg)at 300 mm Hg with a 21-gauge tip,and 32.5±5.0 cm(15.7±3.5 mm Hg)at 250 mm Hg with a 21-gauge tip.CONCLUSION:A comprehensive understanding of this chamber system’s characteristics and usage can resolve anterior chamber instability caused by changing preoperative settings on the phaco machine.
文摘Published proof test coverage(PTC)estimates for emergency shutdown valves(ESDVs)show only moderate agreement and are predominantly opinion-based.A Failure Modes,Effects,and Diagnostics Analysis(FMEDA)was undertaken using component failure rate data to predict PTC for a full stroke test and a partial stroke test.Given the subjective and uncertain aspects of the FMEDA approach,specifically the selection of component failure rates and the determination of the probability of detecting failure modes,a Fuzzy Inference System(FIS)was proposed to manage the data,addressing the inherent uncertainties.Fuzzy inference systems have been used previously for various FMEA type assessments,but this is the first time an FIS has been employed for use with FMEDA.ESDV PTC values were generated from both the standard FMEDA and the fuzzy-FMEDA approaches using data provided by FMEDA experts.This work demonstrates that fuzzy inference systems can address the subjectivity inherent in FMEDA data,enabling reliable estimates of ESDV proof test coverage for both full and partial stroke tests.This facilitates optimized maintenance planning while ensuring safety is not compromised.
文摘To obtain the certificate of airworthiness,it is essential to conduct a full-scale aircraft static test.During such test,accurate and comprehensive wing deformation measurement is crucial for assessing its strength,stiffness,and bearing capability.This paper proposes a novel and cost-effective videogrammetric method using multi-camera system to achieve the non-contact,highprecision,and 3D measurement of overall static deformation for the large-scale wing structure.To overcome the difficulties of making,carrying,and employing the large 2D or 3D target for calibrating the cameras with large field of view,a flexible stereo cameras calibration method combining 1D target and epipolar geometry is proposed.The global calibration method,aided by a total station,is employed to unify the 3D data obtained from various binocular subsystems.A series of static load tests using a 10-meter-long large-scale wing have been conducted to validate the proposed system and methods.Furthermore,the proposed method was applied to the practical wing deformation measurement of both wings with a wingspan of 33.6 m in the full-size civil aircraft static test.The overall 3D profile and displacement data of the tested wing under various loads can be accurately obtained.The maximum error of distance and displacement measurement is less than 4.5 mm within the measurement range of 35 m in all load cases.These results demonstrate that the proposed method achieves effective,high-accuracy,on-site,and visualized wing deformation measurement,making it a promising approach for full-scale aircraft wing static test.
基金supported by the“Shuimu Tsinghua Scholar”Project,China(No.2024SM223)the National Science and Technology Major Project,China(No.Y2022-V-0002-0028).
文摘Aeropropulsion System Test Facility (ASTF) is required to accurately control the pressure and temperature of the airflow to test the performance of the aero-engine. However, the control accuracy of ASTF is significantly affected by the flow disturbance caused by aero-engine acceleration and deceleration. This would reduce the credibility of ASTF’s test results for the aero-engine. Therefore, first, this paper proposes a feedforward compensation-based L1 adaptive control method for ASTF to address this problem. The baseline controller is first designed based on ideal uncoupled closed-loop dynamics to achieve dynamic decoupling. Then, L1 adaptive control is adopted to deal with various uncertainties and ensure good control performance. To further enhance the anti-disturbance performance, a feedforward strategy based on disturbance prediction is designed in the L1 adaptive control framework to compensate for the unmatched flow disturbance, which cannot be measured directly. In addition, this strategy takes into account the effects of actuator dynamics. With this method, the feedforward term can be determined from the nominal model parameters despite uncertainties. Finally, to demonstrate the effectiveness of the proposed method, various comparative experiments are performed on a hardware-in-the-loop system of ASTF. The experimental results show that the proposed method possesses excellent tracking performance, anti-disturbance performance and robustness.
基金Shandong Provincial Natural Science Foundation for Distinguished Young Scholars under Grant No.ZR2022JQ27the Taishan Scholars Program
文摘Transmission tower-line systems(TTLSs)play a crucial role in the long-distance transmission of electrical energy,often necessitating their crossing through active fault areas.However,previous studies have given limited attention to the seismic performance of fault-crossing transmission TTLSs,particularly in terms of considering the impact of permanent ground motion displacements(PGMDs).This study attempts to address this concern by evaluating the seismic performance of TTLSs exposed to fault earthquakes.Three strike-slip ground motions are carefully selected,and the corresponding PGMDs are accurately replicated through baseline adjustment.A meticulously designed and fabricated reduced-scale experimental model of a TTLS is then employed to investigate the influence of the fault crossing location(FCL)on its seismic performance.The shake table tests conducted unequivocally demonstrate that PGMDs significantly amplify the seismic responses of the TTLS and identify the most unfavorable FCL.Furthermore,a finite element model(FEM)is developed and its accuracy is validated by comparing it with the experimental results.Parametric analyses are conducted to explore the effects of fault crossing angles(FCAs)and PGMD amplitudes on the seismic performances of TTLSs.This study is expected to contribute valuable insights for the seismic design and performance analysis of TTLSs crossing fault areas.
文摘This paper introduces a kind of substitute bench testing method for vehicle application development and testing method of the test requirements,including battery fast conversion cycle test equipment,enter type incubator,liquid-cooled machine and ancillary equipment composed of a set of test system,through the walk-in constant temperature box to simulate the new energy vehicles under different environmental conditions of the test requirements,Liquid-cooled machine and auxiliary parts to complete the battery thermal management system need cooling fluid conditions,the battery conversion cycle test equipment to simulate the dc fast charging way of filling pile,complete battery thermal management system test,shorten the filling fast charging time and improve battery fast charge security,for troubleshooting and data collection and analysis,Improve work efficiency,save costs,and eliminate customer anxiety about battery life and charging time.
基金supported in part by National Natural Science Foundation of China under Grant 62201087,Grant 62525101,in part by the National Key R&D Program of China under Grant 2023YFB2904803in part by the Guangdong Major Project of Basic and Applied Basic Research under Grant 2023B0303000001+1 种基金in part by the Natural Science Foundation of Beijing-Xiaomi Innovation Joint Foundation under Grant L243002in part by the Beijing University of Posts and Telecommunications-China Mobile Research Institute Joint Institute.
文摘As the commercialization of the fifth gen-eration communication(5G)is sped up,its system testing scheme is vital for the successful deployment of 5G.Especially,5G relies on the scale-increased multiple-input-multiple output(MIMO)technique to improve its capacity and coverage.Thus,testing new functions of the 5G MIMO system accurately and ef-ficiently,including beamforming(beam-tracking with movement)and multiple-user(MU)multiplexing,is a challenging task.This paper tries to construct a lab-oratorial hardware and conduct equipment-controlled field testing.Firstly,the testing scheme is presented,which is composed of the framework,the channel models and the validation methods.Then,the channel model principles are explained in detail due to its di-rect influence on the testing accuracy.Specifically,we utilize the spatial consistency and the multi-link cor-relation properties to emulate the high-speed dynamic time-varying(HDT)and the multiple-cell(MC)-MU-MIMO channels.Finally,the above testing scheme is verified in a Shanghai 5G field experiment with the practical commercial equipment and the channel em-ulator.The results show that the 5G new functions are tested accurately and efficiently by switching the channel emulation configurations.
文摘Test case prioritization and ranking play a crucial role in software testing by improving fault detection efficiency and ensuring software reliability.While prioritization selects the most relevant test cases for optimal coverage,ranking further refines their execution order to detect critical faults earlier.This study investigates machine learning techniques to enhance both prioritization and ranking,contributing to more effective and efficient testing processes.We first employ advanced feature engineering alongside ensemble models,including Gradient Boosted,Support Vector Machines,Random Forests,and Naive Bayes classifiers to optimize test case prioritization,achieving an accuracy score of 0.98847 and significantly improving the Average Percentage of Fault Detection(APFD).Subsequently,we introduce a deep Q-learning framework combined with a Genetic Algorithm(GA)to refine test case ranking within priority levels.This approach achieves a rank accuracy of 0.9172,demonstrating robust performance despite the increasing computational demands of specialized variation operators.Our findings highlight the effectiveness of stacked ensemble learning and reinforcement learning in optimizing test case prioritization and ranking.This integrated approach improves testing efficiency,reduces late-stage defects,and improves overall software stability.The study provides valuable information for AI-driven testing frameworks,paving the way for more intelligent and adaptive software quality assurance methodologies.
文摘Members of the British Textile Machinery Association(BTMA)can look back on 2025 as a year marked by notable technological advances and continued progress in global trade,despite an uncertain and volatile market.“Our members have been very active over the past 12 months and this has resulted in new technologies for the production of technical fibres and fabrics,the introduction of AI and machine learning into process control systems and significant advances in materials testing,”says BTMA CEO Jason Kent.“There’s real excitement about what can be achieved in 2026 as we look ahead to upcoming exhibitions such as JEC Composites in Paris in March and Techtextil in Frankfurt in April.”
基金Computer Basic Education Teaching Research Project of Association of Fundamental Computing Education in Chinese Universities(Nos.2025-AFCEC-527 and 2024-AFCEC-088)Research on the Reform of Public Course Teaching at Nantong College of Science and Technology(No.2024JGG015).
文摘With the rapid development of artificial intelligence,the intelligence level of software is increasingly improving.Intelligent software,which is widely applied in crucial fields such as autonomous driving,intelligent customer service,and medical diagnosis,is constructed based on complex technologies like machine learning and deep learning.Its uncertain behavior and data dependence pose unprecedented challenges to software testing.However,existing software testing courses mainly focus on conventional contents and are unable to meet the requirements of intelligent software testing.Therefore,this work deeply analyzed the relevant technologies of intelligent software testing,including reliability evaluation indicator system,neuron coverage,and test case generation.It also systematically designed an intelligent software testing course,covering teaching objectives,teaching content,teaching methods,and a teaching case.Verified by the practical teaching in four classes,this course has achieved remarkable results,providing practical experience for the reform of software testing courses.
基金supported in part by the National Science and Technology Council of Taiwan under the contract numbers NSTC 114-2221-E-019-055-MY2 and NSTC 114-2221-E-019-069.
文摘Cloud services,favored by many enterprises due to their high flexibility and easy operation,are widely used for data storage and processing.However,the high latency,together with transmission overheads of the cloud architecture,makes it difficult to quickly respond to the demands of IoT applications and local computation.To make up for these deficiencies in the cloud,fog computing has emerged as a critical role in the IoT applications.It decentralizes the computing power to various lower nodes close to data sources,so as to achieve the goal of low latency and distributed processing.With the data being frequently exchanged and shared between multiple nodes,it becomes a challenge to authorize data securely and efficiently while protecting user privacy.To address this challenge,proxy re-encryption(PRE)schemes provide a feasible way allowing an intermediary proxy node to re-encrypt ciphertext designated for different authorized data requesters without compromising any plaintext information.Since the proxy is viewed as a semi-trusted party,it should be taken to prevent malicious behaviors and reduce the risk of data leakage when implementing PRE schemes.This paper proposes a new fog-assisted identity-based PRE scheme supporting anonymous key generation,equality test,and user revocation to fulfill various IoT application requirements.Specifically,in a traditional identity-based public key architecture,the key escrow problem and the necessity of a secure channel are major security concerns.We utilize an anonymous key generation technique to solve these problems.The equality test functionality further enables a cloud server to inspect whether two candidate trapdoors contain an identical keyword.In particular,the proposed scheme realizes fine-grained user-level authorization while maintaining strong key confidentiality.To revoke an invalid user identity,we add a revocation list to the system flows to restrict access privileges without increasing additional computation cost.To ensure security,it is shown that our system meets the security notion of IND-PrID-CCA and OW-ID-CCA under the Decisional Bilinear Diffie-Hellman(DBDH)assumption.
基金financially supported by ARC Linkage project(LP210200642)ARC Center of Excellence for Quantum Biotechnology(grant no.CE230100021)+1 种基金National Health and Medical Research Council Investigator Fellowship—(grant no.APP2017499)Chan Zuckerberg Initiative Deep Tissue Imaging Phase 2(grant no.DT12-0000000182).
文摘Lateral flow immunoassays(LFIAs)are low-cost,rapid,and easy to use for pointof-care testing(POCT),but the majority of the available LFIA tests are indicative,rather than quantitative,and their sensitivity in antigen tests are usually limited at the nanogram range,which is primarily due to the passive capillary fluidics through nitrocellulose membranes,often associated with non-specific bindings and high background noise.To overcome this challenge,we report a Beads-on-a-Tip design by replacing nitrocellulose membranes with a pipette tip loaded with magnetic beads.The beads are pre-conjugated with capture antibodies that support a typical sandwich immunoassay.This design enriches the low-abundant antigen proteins and allows an active washing process to significantly reduce non-specific bindings.To further improve the detection sensitivity,we employed upconversion nanoparticles(UCNPs)as luminescent reporters and SARS-CoV-2 spike(S)antigen as a model analyte to benchmark the performance of this design against our previously reported methods.We found that the key to enhance the immunocomplex formation and signal-to-noise ratio lay in optimizing incubation time and the UCNP-to-bead ratio.We therefore successfully demonstrated that the new method can achieve a very large dynamic range from 500 fg/mL to 10μg/mL,across over 7 digits,and a limit of detection of 706 fg/mL,nearly another order of magnitude lower than the best reported LFIA using UCNPs in COVID-19 spike antigen detection.Our system offers a promising solution for ultra-sensitive and quantitative POCT diagnostics.
基金supported by the Andalusian FEDER Operational Program [B-CTS-374-UGR20 and C-SEJ-015-UGR23]the Spanish Ministry of Science,Innovation and Universities [PGC2018-097388-BI00-MCI/AEI/FEDER,UE]。
文摘Purpose: Normobaric hypoxia(NH) is a frequent strategy for training under hypoxic conditions that can be administered through different equipment, including face masks or hypoxic chambers/tents. Nonetheless, the versatility of administration methods may influence the outcomes.Methods: Web of Science, Scopus, SPORTDiscus and Pub Med/MEDLINE were searched to identify studies assessing the effect of NH administered by face mask or chamber/tent equipment on maximal oxygen uptake( VO2max) after a training period. An overall meta-analysis and sub-analysis of total program session volume(low, moderate, high), participants' training level(trained, active, sedentary), and the severity of hypoxia(moderate, severe) were conducted to explore the effects of the NH-administration system.Results: Eighteen studies were included. Compared with normoxia, NH showed a moderate global improvement in VO2max(standardized mean difference [SMD] = 0.74;p = 0.06), favoring the chamber/tent(SMD = 1.30;p< 0.01) over the face mask. Sub-analysis showed a very large effect in support of the hypoxic chamber/tent among sedentary individuals and training programs with a high volume of sessions. Severe hypoxia did not yield conclusive findings in VO2max improvements, although the chamber/tent proved more effective(SMD = 1.42;p< 0.01) than the face mask under moderate hypoxia.Conclusions: Chambers/tents may slightly accentuate the benefit of NH on aerobic performance, particularly in participants with limited training experience following a high volume of sessions under moderate hypoxia.However, the variability of sub-analysis factors(session volume, participants' training level, and methodological approaches) between studies using each type of hypoxia-generating equipment may influence this result.
基金supported by the National Social Science Foundation of China under Grant No.23&ZD126National Science Foundation of China under Grant No.12471256+1 种基金Natural Science Foundation of Shanxi Province under Grant No.202203021221219Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi under Grant No.2023L164。
文摘The authors consider the issue of hypothesis testing in varying-coefficient regression models with high-dimensional data.Utilizing kernel smoothing techniques,the authors propose a locally concerned U-statistic method to assess the overall significance of the coefficients.The authors establish that the proposed test is asymptotically normal under both the null hypothesis and local alternatives.Based on the locally concerned U-statistic,the authors further develop a globally concerned U-statistic to test whether the coefficient function is zero.A stochastic perturbation method is employed to approximate the distribution of the globally concerned test statistic.Monte Carlo simulations demonstrate the validity of the proposed test in finite samples.
基金supported by the Fundamental Research Funds for the Central Universities in UIBE under Grant No.CXTD14-05。
文摘Smartphone-based electrocardiograms(ECGs)are increasingly utilized for monitoring atrial fibrillation(AF)recurrence after catheter ablation(CA),referred to as smartphone AF burden(SMURDEN).The SMURDEN data often exhibit complex patterns of zero AF episodes,which may arise from either true AF-free status(structural zeros)or missed AF episodes due to intermittent monitoring(random zeros).Such a mixture of AF-free and at-risk patients can lead to zero-inflation in the data.The authors propose a novel zero-inflation test for binomial regression models to identify recurrence-free AF populations.Unlike traditional approaches requiring fully specified zero-inflated models,the proposed test utilizes a weighted average of the discrepancies between observed and expected zero proportions,with weights determined by binomial sizes.A closed-form test statistic is developed,and its asymptotic distribution is derived using estimating equations.Simulations demonstrate superior performance over existing methods,and real-world AF monitoring data validate the practical utility of our proposed test.
