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Analysis and Application of the Synthetic Relative Measuring Method in On-Line Monitoring for Capacitive Equipment in Power Systems
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作者 Qing Guo Li-Jun Qin Hua-Wei Jin 《Journal of Electronic Science and Technology》 CAS 2011年第3期270-277,共8页
On-line measurement for dielectric loss angle can effectively monitor the insulation condition of capacitive equipment in power systems. Synthetic relative measuring methods not only markedly overcome the shortcomings... On-line measurement for dielectric loss angle can effectively monitor the insulation condition of capacitive equipment in power systems. Synthetic relative measuring methods not only markedly overcome the shortcomings of traditional absolute measuring methods but also greatly improve the accuracy of dielectric loss angle measurement. However, synthetic relative measuring methods based on two or three pieces of capacitive equipment do not have the characteristic of generality. In this paper, a principle of synthetic relative measuring method is presented. The example of application for synthetic relative methods based on three and four pieces of capacitive equipment running in the same phase is taken to present the failure judgment matrices for N pieces of equipment. According to these matrices, the fault condition of N pieces of capacitive equipment can be watched, which is more general. Then some problems needing to be concerned along with two diagnostic methods used in diagnostic system are introduced. Finally, two programmable flow charts for the two methods are given and corresponding examples demonstrate their feasibility in practice. 展开更多
关键词 Index Terms-Capacitive equipment dielectric loss angle on-line monitoring synthetic relative measuring method failure judgment matrix.
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Infrastructure of Synchrotronic Biosensor Based on Semiconductor Device Fabrication for Tracking, Monitoring, Imaging, Measuring, Diagnosing and Detecting Cancer Cells
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作者 Alireza Heidari 《Semiconductor Science and Information Devices》 2019年第2期29-57,共29页
Copper Zinc Antimony Sulfide(CZAS)is derived from Copper Antimony Sulfide(CAS),a famatinite class of compound.In the current paper,the first step for using Copper,Zinc,Antimony and Sulfide as materials in manufacturin... Copper Zinc Antimony Sulfide(CZAS)is derived from Copper Antimony Sulfide(CAS),a famatinite class of compound.In the current paper,the first step for using Copper,Zinc,Antimony and Sulfide as materials in manufacturing synchrotronic biosensor-namely increasing the sensitivity of biosensor through creating Copper Zinc Antimony Sulfide,CZAS(Cu1.18Zn0.40Sb1.90S7.2)semiconductor and using it instead of Copper Tin Sulfide,CTS(Cu2SnS3)for tracking,monitoring,imaging,measuring,diagnosing and detecting cancer cells,is evaluated.Further,optimization of tris(2,2'-bipyridyl)ruthenium(II)(Ru(bpy)32+)concentrations and Copper Zinc Antimony Sulfide,CZAS(Cu1.18Zn0.40Sb1.90S7.2)semiconductor as two main and effective materials in the intensity of synchrotron for tracking,monitoring,imaging,measuring,diagnosing and detecting cancer cells are considered so that the highest sensitivity obtains.In this regard,various concentrations of two materials were prepared and photon emission was investigated in the absence of cancer cells.On the other hand,ccancer diagnosis requires the analysis of images and attributes as well as collecting many clinical and mammography variables.In diagnosis of cancer,it is important to determine whether a tumor is benign or malignant.The information about cancer risk prediction along with the type of tumor are crucial for patients and effective medical decision making.An ideal diagnostic system could effectively distinguish between benign and malignant cells;however,such a system has not been created yet.In this study,a model is developed to improve the prediction probability of cancer.It is necessary to have such a prediction model as the survival probability of cancer is high when patients are diagnosed at early stages. 展开更多
关键词 Synchrotronic Biosensor Copper Zinc Antimony Sulfide CZAS(Cu1.18Zn0.40Sb1.90S7.2)Semiconductor Photomultiplier Semiconductor Device TRACKING monitoring IMAGING measuring Diagnosing Detecting Cancer Cells Tris(2 2'-bipyridyl)ruthenium(II)(Ru(bpy)32+)
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Modeling and monitoring of nonlinear multi-mode processes based on similarity measure-KPCA 被引量:10
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作者 WANG Xiao-gang HUANG Li-wei ZHANG Ying-wei 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第3期665-674,共10页
A new modeling and monitoring approach for multi-mode processes is proposed.The method of similarity measure(SM) and kernel principal component analysis(KPCA) are integrated to construct SM-KPCA monitoring scheme,wher... A new modeling and monitoring approach for multi-mode processes is proposed.The method of similarity measure(SM) and kernel principal component analysis(KPCA) are integrated to construct SM-KPCA monitoring scheme,where SM method serves as the separation of common subspace and specific subspace.Compared with the traditional methods,the main contributions of this work are:1) SM consisted of two measures of distance and angle to accommodate process characters.The different monitoring effect involves putting on the different weight,which would simplify the monitoring model structure and enhance its reliability and robustness.2) The proposed method can be used to find faults by the common space and judge which mode the fault belongs to by the specific subspace.Results of algorithm analysis and fault detection experiments indicate the validity and practicability of the presented method. 展开更多
关键词 process monitoring kernel principal component analysis (KPCA) similarity measure subspace separation
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Local measurement for structural health monitoring 被引量:1
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作者 祁贵仲 郭迅 +2 位作者 齐霄斋 董伟民 P.Chang 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2005年第1期165-172,共8页
Localized nature of damage in structures requires local measurements for structural health monitoring. The local measurement means to measure the local, usually higher modes of the vibration in a structure. Three fund... Localized nature of damage in structures requires local measurements for structural health monitoring. The local measurement means to measure the local, usually higher modes of the vibration in a structure. Three fundamental issues about the local measurement for structural health monitoring including (1) the necessity of making local measurement, (2) the difficulty of making local measurement and (3) how to make local measurement are addressed in this paper. The results from both the analysis and the tests show that the local measurement can successfully monitor the structural health status as long as the local modes are excited. Unfortunately, the results also illustrate that it is difficult to excite local modes in a structure. Therefore, in order to carry structural health monitoring into effect, we must (1) ensure that the local modes are excited, and (2) deploy enough sensors in a structure so that the local modes can be monitored. 展开更多
关键词 structure health monitoring local measurement local modes higher modes local modes EXCITATION SENSORS structural vibration
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Structural Health Monitoring by Accelerometric Data of a Continuously Monitored Structure with Induced Damages
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作者 Giada Faraco Andrea Vincenzo De Nunzio +1 位作者 Nicola Ivan Giannoccaro Arcangelo Messina 《Structural Durability & Health Monitoring》 EI 2024年第6期739-762,共24页
The possibility of determining the integrity of a real structure subjected to non-invasive and non-destructive monitoring,such as that carried out by a series of accelerometers placed on the structure,is certainly a g... The possibility of determining the integrity of a real structure subjected to non-invasive and non-destructive monitoring,such as that carried out by a series of accelerometers placed on the structure,is certainly a goal of extreme and current interest.In the present work,the results obtained from the processing of experimental data of a real structure are shown.The analyzed structure is a lattice structure approximately 9 m high,monitored with 18 uniaxial accelerometers positioned in pairs on 9 different levels.The data used refer to continuous monitoring that lasted for a total of 1 year,during which minor damage was caused to the structure by alternatively removing some bracings and repositioning them in the structure.Two methodologies detecting damage based on decomposition techniques of the acquired data were used and tested,as well as a methodology combining the two techniques.The results obtained are extremely interesting,as all the minor damage caused to the structure was identified by the processing methods used,based solely on the monitored data and without any knowledge of the real structure being analyzed.The results use 15 acquisitions in environmental conditions lasting 10 min each,a reasonable amount of time to get immediate feedback on possible damage to the structure. 展开更多
关键词 Structural health monitoring damage detection vibration measurements stochastic subspace identification
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Instantaneous frequency measurement using two parallel I/Q modulators based on optical power monitoring 被引量:1
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作者 Chuangye Wang Tigang Ning +3 位作者 Jing Li Li Pei Jingjing Zheng Jingchuan Zhang 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第1期215-220,共6页
A scheme for instantaneous frequency measurement(IFM)using two parallel I/Q modulators based on optical power monitoring is proposed.The amplitude comparison function(ACF)can be constructed to establish the relationsh... A scheme for instantaneous frequency measurement(IFM)using two parallel I/Q modulators based on optical power monitoring is proposed.The amplitude comparison function(ACF)can be constructed to establish the relationship between the frequency of radio frequency(RF)signal and the power ratio of two optical signals output by two I/Q modulators.The frequency of RF signal can be derived by measuring the optical power of the optical signals output by two I/Q modulators.The measurement range and measurement error can be adjusted by controlling the delay amount of the electrical delay line.The feasibility of the scheme is verified,and the corresponding measurement range and measurement error of the system under different delay amounts of the electrical delay line are given.Compared with previous IFM schemes,the structure of this scheme is simple.Polarization devices,a photodetector and an electrical power meter are not used,which reduces the impact of the environmental disturbance on the system and the cost of the system.In simulation,the measurement range can reach 0 GHz-24.5 GHz by adjusting the delay amount of the electrical delay lineτ=20 ps.The measurement error of the scheme is better at low frequency,and the measurement error of low frequency 0 GHz-9.6 GHz can reach-0.1 GHz to+0.05 GHz. 展开更多
关键词 microwave photonics instantaneous frequency measurement optical power monitoring
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Automatic Monitoring System for 3-D Deformation of Crustal Fault Based on Laser and Machine Vision
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作者 Qingshan Wang Guoying Su +3 位作者 Qingzun Ma Haiquan Yin Zhihang Liu Chuanzhen Lv 《Instrumentation》 2024年第2期44-52,共9页
An automatic monitoring method of the 3-D deformation is presented for crustal fault based on laser and machine vision. The laser source and screen are independently set up in the headwall and footwall, the collimated... An automatic monitoring method of the 3-D deformation is presented for crustal fault based on laser and machine vision. The laser source and screen are independently set up in the headwall and footwall, the collimated laser beam creates a circular spot on the screen, meanwhile, the industrial camera captures the tiny deformation of the crustal fault by monitoring the change of the spot position. This method significantly reduces the cost of equipment and labor, provides daily sampling to ensure high continuity of data. A prototype of the automatic monitoring system is developed, and a repeatability test indicates that the error of spot jitter can be minimized by consecutive samples. Meanwhile, the environmental correction model is determined to ensure that environmental changes do not disturb the system. Furthermore, the automatic monitoring system has been applied at the deformation monitoring station(KJX02) of China Beishan underground research laboratory, where continuous deformation monitoring is underway. 展开更多
关键词 deformation measurement crustal fault automatic monitoring laser spot machine vision
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Dynamic Monitoring and Control Measures of Spodoptera frugiperda(J.E.Smmith) in Low Latitude Plateau Sugarcane Areas
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作者 Xiaoyan CANG Rongyue ZHANG +5 位作者 Jiong YIN Hongli SHAN Jie LI Xiaoyan WANG Zhiming LUO Yinkun HUANG 《Agricultural Biotechnology》 CAS 2019年第5期70-72,75,共4页
Spodoptera frugiperda (J.E.Smmith) is one of the major migratory pests warned by the Food and Agriculture Organization (FAO).It has been successfully invaded sugarcane and corn in Jinggu,Longchuan,Gengma,Menghai,Yingj... Spodoptera frugiperda (J.E.Smmith) is one of the major migratory pests warned by the Food and Agriculture Organization (FAO).It has been successfully invaded sugarcane and corn in Jinggu,Longchuan,Gengma,Menghai,Yingjiang,Lancang of Yunan Province,China.In view of the great variety of hosts,wide range of habitats and strong migration ability,S.frugiperda has the potential of causing catastrophic threats to sugarcane production.In this paper,we made a systematic introduction to the morphological and biological characteristics of S.frugiperda,analyzed its occurrence situations and occurrence trends in Yunnan of China and other countries around the world,and proposed the control strategies and measures of ecological regulation and control,natural enemies protection and utilization,biological control,pesticide control and adults trapping based on the outbreak characteristics of S.frugiperda and the actual sugarcane production in low latitude plateau areas. 展开更多
关键词 Low LATITUDE PLATEAU areas SPODOPTERA frugiperda OCCURRENCE Dynamic monitoring Prevention and control measures
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Monitoring of the Corrosion on a Steel Sheet-Pile Marine Breakwater by Systematic Thickness Measurements
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作者 Luis Osmel Millan Solorzano 《Journal of Civil Engineering and Architecture》 2018年第1期39-50,共12页
In Quepos, Pacific of Costa Rica, it was finished on 2010 the first phase of a marina, including two mix breakwaters, with rubble mound (rocks and concrete units), and 25 circular steel sheet piles cofferdam cells, ... In Quepos, Pacific of Costa Rica, it was finished on 2010 the first phase of a marina, including two mix breakwaters, with rubble mound (rocks and concrete units), and 25 circular steel sheet piles cofferdam cells, filled with sand and gravel. The maintenance plan, considers tracking sheet pile corrosion, comparing "actual" against expected rates, checking structural limits, and programming countermeasures if accelerated corrosion is identified. Specific control sections, along the breakwaters, both inside and outside the basin, were established. In each section, thicknesses were measured every meter from the top of the steel cell to seabed using an ultrasonic equipment, and an underwater transducer. Both land crew, and divers for submerged portions, were used. The measurements campaigns are for several years from 2011 to 2016. Sectors of the breakwater with varied corrosion attack levels could be differentiated. Also, corrosion rates and lifespans were estimated, both general for the structures, and specific for each section and level. In turn, this allowed to identify maintenance priorities, defining sites where measures of corrosion protection should initiate, as well, to have confidence in the structural capacity and safety of the breakwaters. 展开更多
关键词 monitoring of structures maritime works sheet piling CORROSION ultrasonic thickness measurements.
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Study on Factors Influencing the Quality of Automatic Monitoring Data of Pollution Sources and Technical Assurance Measures
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作者 Hanju BAO Yun WU Chengxin PAN 《Meteorological and Environmental Research》 CAS 2021年第6期53-58,共6页
Automatic monitoring data of pollution sources is an important basis for environmental supervision and management.At present,it is difficult to guarantee the quality of automatic monitoring data of pollution sources,a... Automatic monitoring data of pollution sources is an important basis for environmental supervision and management.At present,it is difficult to guarantee the quality of automatic monitoring data of pollution sources,and it is difficult to play the role of the monitoring data.In response to this problem,the factors influencing the quality of automatic monitoring data of pollution sources were analyzed in detail,and technical assurance measures for the quality of automatic monitoring data of pollution sources in Shandong Province were studied.Besides,the dynamic management and control idea of automatic monitoring of pollution sources was proposed,and specific technical measures were analyzed from five aspects of standardizing automatic monitoring equipment of pollution sources,improving the data collection and transmission system,establishing a mechanism for reporting operating status information of monitoring equipment,setting alarm rules and alarm processing procedures,and statistically analyzing the operating status of the equipment.Practice has proved that the dynamic management and control system can effectively ensure the quality of automatic monitoring data of pollution sources. 展开更多
关键词 Automatic monitoring Quality assurance Technical measures Dynamic management and control
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Monitoring of the Corrosion on a Steel Sheet-pile Marine Breakwater by Systematic Thickness Measurements
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作者 Millan Solorzano Luis Osmel Luis Osmel 《Journal of Civil Engineering and Architecture》 2022年第10期519-530,共12页
In Quepos,Pacific of Costa Rica,it was finished on 2010 the first phase of a marina,including two mix breakwaters,with rubble mound(rocks and concrete units),and 25 circular steel sheet piles cofferdam cells,filled wi... In Quepos,Pacific of Costa Rica,it was finished on 2010 the first phase of a marina,including two mix breakwaters,with rubble mound(rocks and concrete units),and 25 circular steel sheet piles cofferdam cells,filled with sand and gravel.The maintenance plan,considers tracking sheet pile corrosion,comparing'actual'against expected rates,checking structural limits,and programming countermeasures if accelerated corrosion is identified.Specific control sections,along the breakwaters,both inside and outside the basin,were established.In each section,thicknesses were measured every meter from the top of the steel cell to seabed using an ultrasonic equipment,and an underwater transducer.Both land crew,and divers for submerged portions,were used.The measurements campaigns are for several years from 2011 to 2016.Sectors of the breakwater with varied corrosion attack levels could be differentiated.Also,corrosion rates and lifespans were estimated,both general for the structures,and specific for each section and level.In turn,this allowed to identify maintenance priorities,defining sites where measures of corrosion protection should initiate,as well,to have confidence in the structural capacity and safety of the breakwaters. 展开更多
关键词 monitoring of structures maritime works sheet piling CORROSION ultrasonic thickness measurements
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Construction Technology and Safety Monitoring Measures of Road and Bridge Engineering
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作者 Wei Wang 《Journal of Architectural Research and Development》 2021年第5期31-34,共4页
With the acceleration of urbanization and the continuous improvement of urban infrastructure construction,roads and bridges,as an important infrastructure content in China,directly affect people's daily travel.The... With the acceleration of urbanization and the continuous improvement of urban infrastructure construction,roads and bridges,as an important infrastructure content in China,directly affect people's daily travel.Therefore,the construction and management of roads and bridges must be improved to ensure the quality and safety of roads and bridges and effectively prevent safety accidents.Strengthen the management of road and bridge construction through safety monitoring,improve the safety factor of the project and ensure people's travel safety.This paper mainly analyzes the common diseases and construction technology of road and bridge engineering construction,and puts forward safety monitoring measures. 展开更多
关键词 Road and bridge works Construction technology Safety monitoring measures
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Research on geo-electrical resistivity observation system specially used for earthquake monitoring in China 被引量:7
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作者 Jialiu Zhao Lanwei Wang Jiadong Qian 《Earthquake Science》 CSCD 2011年第6期497-511,共15页
This paper deals with the design and development of the observational system of geo-electrical resistivity on the basis of the demands for exploring the temporal variations of electrical properties of Earth media in t... This paper deals with the design and development of the observational system of geo-electrical resistivity on the basis of the demands for exploring the temporal variations of electrical properties of Earth media in the fixed points of the networks, which would be associated with the earthquake preparation. The observation system is characterized by the high accuracy in measurement, long term stability in operation and high level of rejection to the environmental interference. It consists of three main parts, configuration system measurement system, the calibration and inspection system. 展开更多
关键词 geo-electrical resistivity observation system earthquake monitoring configuration system measurement system calibration and inspection system
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Optical fiber FBG linear sensing systems for the on-line monitoring of airborne high temperature air duct leakage 被引量:2
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作者 Qinyu Wang Xinglin Tong +3 位作者 Cui Zhang Chengwei Deng Siyu Xu Jingchuang Wei 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第8期410-417,共8页
Electrical sensing systems, such as those involving eutectic salt, are mostly used in connection to leakage from existing airborne high-temperature air-conducting pipelines. Such complex structured systems are suscept... Electrical sensing systems, such as those involving eutectic salt, are mostly used in connection to leakage from existing airborne high-temperature air-conducting pipelines. Such complex structured systems are susceptible to external interferences and, thus, cannot meet the increasingly strict monitoring needs of a complex air-conducting pipeline system of an aircraft. In view of this point, this paper studies an alternative sensor system based on a dense array fiber grating. To obtain a compact and light-weight airborne signal processing system, a field programmable gate array is used as the main control core that controls the output of the light source. The functions of pulse modulation, analog-to-digital conversion,data buffering and transmission are integrated into a single system, while the linear sensing monitoring is obtained by detecting the time-division and wavelength-division wavelength drift signals of the fiber Bragg grating array. Our experiments show that the spatial resolution of the linear sensing system approaches 5 cm, the temperature measurement accuracy reaches 2 ℃, the temperature measurement range is between 0–250 ℃, and the response time is within 4 s. Compared with the existing electrical monitoring systems, various monitoring indicators have been greatly improved and have broad application prospects. 展开更多
关键词 gating array quasi-distributed measurement temperature monitoring prague grating MINIATURIZATION
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Ground control monitoring of retreat room–and–pillar mine in Central Appalachia 被引量:2
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作者 Erik C.Westman Ryan J.Molka William J.Conrad 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2017年第1期65-69,共5页
In order to study pillar and overburden response to retreat mining, a ground control program was conducted at a Central Appalachian Mine. The program consisted of several monitoring methods including a seismic monitor... In order to study pillar and overburden response to retreat mining, a ground control program was conducted at a Central Appalachian Mine. The program consisted of several monitoring methods including a seismic monitoring system, borehole pressure cells in the pillars, and time-lapse photogrammetry of the pillar ribs. Two parallel geophone arrays were installed, one on each side of the panel with the sensors mounted 3 m into the roof. A total of fourteen geophones recorded more than 5000 events during the panel retreat. A MIDAS datalogger was used to record pressure from borehole pressure cells(BPCs)located in two adjacent pillars that were not mined during retreat. A series of photographs were taken of the pillars that had the BPCs as the face approached so that deformation of the entire rib could be monitored using photogrammetry. Results showed that pillar stability and cave development were as expected. The BPCs showed an increase in loading when the face was 115 m inby and a clear onset of the forward abutment at 30 m. The photogrammetry results displayed pillar deformation corresponding to the increased loading. The microseismic monitoring results showed the overburden caving inby the face, again as expected. The significance of these results lies in two points,(1) we can quantify the safe manner in which this mine is conducting retreating operations, and(2) we can use volumetric technologies(photogrammetry and microseismic) to monitor entire volumes of the mine in addition to the traditional point-location geotechnical measurements(BPCs). 展开更多
关键词 Retreat mining Stress measurement Microseismic monitoring Pillar stability
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A new process monitoring method based on noisy time structure independent component analysis 被引量:2
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作者 蔡连芳 田学民 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第1期162-172,共11页
Conventional process monitoring method based on fast independent component analysis(Fast ICA) cannot take the ubiquitous measurement noises into account and may exhibit degraded monitoring performance under the advers... Conventional process monitoring method based on fast independent component analysis(Fast ICA) cannot take the ubiquitous measurement noises into account and may exhibit degraded monitoring performance under the adverse effects of the measurement noises. In this paper, a new process monitoring approach based on noisy time structure ICA(Noisy TSICA) is proposed to solve such problem. A Noisy TSICA algorithm which can consider the measurement noises explicitly is firstly developed to estimate the mixing matrix and extract the independent components(ICs). Subsequently, a monitoring statistic is built to detect process faults on the basis of the recursive kurtosis estimations of the dominant ICs. Lastly, a contribution plot for the monitoring statistic is constructed to identify the fault variables based on the sensitivity analysis. Simulation studies on the continuous stirred tank reactor system demonstrate that the proposed Noisy TSICA-based monitoring method outperforms the conventional Fast ICA-based monitoring method. 展开更多
关键词 Process monitoring Independent component analysis measurement noises KURTOSIS Mixing matrix Contribution plot Sensitivity analysis
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Research on an active and continuous monitoring system for human respiratory system 被引量:2
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作者 于莲芝 Yan Guozheng +1 位作者 Zhang Wenqiang Wang Xiangrui 《High Technology Letters》 EI CAS 2006年第1期68-71,共4页
Continuous and dynamic measurements of human respiratory parameters are very important for vital diseases of respiratory system during mechanical ventilation. This paper analyzed the structure and mechanical propertie... Continuous and dynamic measurements of human respiratory parameters are very important for vital diseases of respiratory system during mechanical ventilation. This paper analyzed the structure and mechanical properties of the human respiratory system, and designed an active intervening monitoring micro system for it. The mobile mechanism of the micro system is soft and earthworm-like movement actuated by pneumatic rubber actuator, the measurement and therapy unit of the system is an extensible mechanism with sensors in the front. The micro monitoring system can move in respiratory tract and measure the respiratory parameters in bronchium continuously. Experiments had been done in swine's respiratory tract, the results proved that the micro robot system could measure the respiratory parameters in real-time successfully and its movement was smith in swine's respiratory tract. 展开更多
关键词 respiratory system monitoring system mechanical ventilation measurEMENT
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New Monitoring Technologies for Overhead Contact Line at 400 km.h-1 被引量:2
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作者 Chul.Jin Cho Young Park 《Engineering》 SCIE EI 2016年第3期360-365,共6页
Various technologies have recently been developed for high-speed railways, in order to boost commercial speeds from 300 km.h: to 400 km.h-1. Among these technologies, this paper introduces the 400 km-h-1 class curren... Various technologies have recently been developed for high-speed railways, in order to boost commercial speeds from 300 km.h: to 400 km.h-1. Among these technologies, this paper introduces the 400 km-h-1 class current collection performance evaluation methods that have been developed and demonstrated by Korea. Specifically, this paper reports details of the video-based monitoring techniques that have been adopted to inspect the stability of overhead contact line (OCL) components at 400 km.h-1 without direct contact with any components of the power supply system. Unlike conventional OCL monitoring systems, which detect contact wire positions using either laser sensors or line cameras, the developed system measures parameters in the active state by video data. According to experimental results that were obtained at a field-test site established at a commercial line, it is claimed that the proposed mea- surement system is capable of effectively measuring OCL parameters. 展开更多
关键词 High-speed railway Overhead contact lines Condition monitoring Image processing based measurement
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3D Microdisplacement Monitoring of Large Aircraft Assembly with Automated In Situ Calibration 被引量:1
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作者 Zhenyuan Jia Bing Liang +2 位作者 Wei Liu Kun Liu Jianwei Ma 《Engineering》 SCIE EI CAS 2022年第12期105-116,共12页
Three-dimensional(3D)microdisplacement monitoring plays a crucial role in the assembly of large aircraft.This paper presents a broadly applicable high-precision online 3D microdisplacement monitoring method and system... Three-dimensional(3D)microdisplacement monitoring plays a crucial role in the assembly of large aircraft.This paper presents a broadly applicable high-precision online 3D microdisplacement monitoring method and system based on proximity sensors as well as a corresponding in situ calibration method,which can be applied under various extreme working conditions encountered in the aircraft assembly process,such as compact and obstructed spaces.A 3D monitoring model is first established to achieve 3D microdisplacement monitoring based only on the one-dimensional distances measured by proximity sensors,which concerns the extrinsic sensor parameters,such as the probe base point(PBP)and the unit displacement vector(UDV).Then,a calibration method is employed to obtain these extrinsic parameters with high precision by combining spatial transformation principles and weighted optimization.Finally,calibration and monitoring experiments performed for a tailplane assembly process are reported.The calibration precision for the PBP is better than±10 lm in the X and Y directions and±2 lm in the Z direction,and the calibration precision for the UDV is better than 0.07°.Moreover,the accuracy of the 3D microdisplacement monitoring system can reach±15 lm.In general,this paper provides new insights into the modeling and calibration of 3D microdisplacement monitoring based on proximity sensors and a precise,efficient,and low-cost technical means for performing related measurements in compact spaces during the aircraft assembly process. 展开更多
关键词 Aircraft manufacture ASSEMBLY CALIBRATION Condition monitoring Displacement measurement
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Monitoring of Real-Time Complex Deformed Shapes of Thin-Walled Channel Beam Structures Subject to the Coupling Between Bi-Axial Bending and Warping Torsion 被引量:2
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作者 Rui Lu Zhanjun Wu +1 位作者 Qi Zhou Hao Xu 《Structural Durability & Health Monitoring》 EI 2019年第3期267-287,共21页
Structural health monitoring(SHM)is a research focus involving a large category of techniques performing in-situ identification of structural damage,stress,external loads,vibration signatures,etc.Among various SHM tec... Structural health monitoring(SHM)is a research focus involving a large category of techniques performing in-situ identification of structural damage,stress,external loads,vibration signatures,etc.Among various SHM techniques,those able to monitoring structural deformed shapes are considered as an important category.A novel method of deformed shape reconstruction for thinwalled beam structures was recently proposed by Xu et al.[1],which is capable of decoupling complex beam deformations subject to the combination of different loading cases,including tension/compression,bending and warping torsion,and also able to reconstruct the full-field displacement distributions.However,this method was demonstrated only under a relatively simple loading coupling cases,involving uni-axial bending and warping torsion.The effectiveness of the method under more complex loading cases needs to be thoroughly investigated.In this study,more complex deformations under the coupling between bi-axial bending and warping torsion was decoupled using the method.The set of equations for deformation decoupling was established,and the reconstruction algorithm for bending and torsion deformation were utilized.The effectiveness and accuracy of the method was examined using a thin-walled channel beam,relying on analysis results of finite element analysis(FEA).In the analysis,the influence of the positions of the measurement of surface strain distributions on the reconstruction accuracy was discussed.Moreover,different levels of measurement noise were added to the axial strain values based on numerical method,and the noise resistance ability of the deformation reconstruction method was investigated systematically.According to the FEA results,the effectiveness and precision of the method in complex deformation decoupling and reconstruction were demonstrated.Moreover,the immunity of the method to measurement noise was proven to be considerably strong. 展开更多
关键词 Structural health monitoring deformation reconstruction finite element analysis strain measurement channel section beam
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