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MEASUREMENT OF ANGULAR VIBRATION AMPLITUDE BY ACTIVELY BLURRED IMAGES 被引量:1
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作者 GUAN Baiqing WANG Shigang LIU Chong LI Qian 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2007年第1期77-81,共5页
A novel motion-blur-based method for measuring the angular amplitude of a high-frequency rotational vibration is schemed. The proposed approach combines the active vision concept and the mechanism of motion-from-blur,... A novel motion-blur-based method for measuring the angular amplitude of a high-frequency rotational vibration is schemed. The proposed approach combines the active vision concept and the mechanism of motion-from-blur, generates motion blur on the image plane actively by extending exposure time, and utilizes the motion blur information in polar images to estimate the angular amplitude of a high-frequency rotational vibration. This method obtains the analytical results of the angular vibration amplitude from the geometric moments of a motion blurred polar image and an unblurred image for reference. Experimental results are provided to validate the presented scheme. 展开更多
关键词 Vibration measurement Rotational vibration active vision Motion blur Geometric moment
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Technique and experiment of active direct gas pressure measurement in coal roadway
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作者 CHEN Xue-xi MA Shang-quan QI Li-ming 《Journal of Coal Science & Engineering(China)》 2009年第2期210-214,共5页
An active measurement method and its principle was introduced consideringthe low success rate,special difficulty,and long measurement time of the direct gas pressuremeasurement currently used in coal roadways.The tech... An active measurement method and its principle was introduced consideringthe low success rate,special difficulty,and long measurement time of the direct gas pressuremeasurement currently used in coal roadways.The technology of drilling,boreholesealing depth,borehole sealing length,sealing control of the measuring process,compensatorycomputation of gas loss quantity and other key techniques were discussed.Finally,based on the latest instrument the authors developed,a series of experiments of directgas pressure measurement in the coal roadways of the Jincheng and Tongchuanmine district,were carried out.The experimental results show that active gas pressuremeasurement technique has advantages as follows:(1) the application scope of direct gaspressure measurement technique is wide and it does not have the restriction of coalhardness,coal seam fissure and other conditions;(2) the measured results are credible,which can be tested by the same gas pressure value acquired from a different borehole inthe same place;(3) the measurement process is convenient and quick,it takes about 2 to3 days to acquire the gas pressure value in a coal seam. 展开更多
关键词 coal roadway active gas pressure measurement method key techniques experimental research
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HSCP:a hardware and software combined platform to improve precision in active network measurement
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作者 王志东 Li Wenfa +1 位作者 Xu Qingjie Mao Jianbiao 《High Technology Letters》 EI CAS 2014年第2期173-178,共6页
In this paper,an active network measurement platform is proposed which is a combination of hardware and software.Its innovation lies in the high performance of hardware combined with features that the software is easy... In this paper,an active network measurement platform is proposed which is a combination of hardware and software.Its innovation lies in the high performance of hardware combined with features that the software is easy to program,which retains software flexibility at the same time.By improving the precision of packet timestamp programmable hardware equipment,it provides packet sending control more accurately and supports the microsecond packet interval.We have implemented a model on the NetMagic platform,and done some experiments to analyze the accuracy difference of the user,the kernel and hardware timestamp. 展开更多
关键词 active network measurement TIMESTAMP packet transmission control
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Leveraging Active Decremental TTL Measuring for Flexible and Efficient NAT Identification 被引量:1
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作者 Tao Yang Chengyu Wang +3 位作者 Tongqing Zhou Zhiping Cai Kui Wu Bingnan Hou 《Computers, Materials & Continua》 SCIE EI 2022年第3期5179-5198,共20页
Malicious attacks can be launched by misusing the network address translation technique as a camouflage.To mitigate such threats,network address translation identification is investigated to identify network address t... Malicious attacks can be launched by misusing the network address translation technique as a camouflage.To mitigate such threats,network address translation identification is investigated to identify network address translation devices and detect abnormal behaviors.However,existingmethods in this field are mainly developed for relatively small-scale networks and work in an offline manner,which cannot adapt to the real-time inference requirements in high-speed network scenarios.In this paper,we propose a flexible and efficient network address translation identification scheme based on actively measuring the distance of a round trip to a target with decremental time-tolive values.The basic intuition is that the incoming and outgoing traffic froma network address translation device usually experiences the different number of hops,which can be discovered by probing with dedicated time-to-live values.We explore a joint effort of parallel transmission,stateless probes,and flexible measuring reuse to accommodate the efficiency of the measuring process.We further accelerate statistical countingwith a new sublinear space data structure Bi-sketch.We implement a prototype and conduct real-world deployments with 1000 volunteers in 31 Chinese provinces,which is believed to bring insight for ground truth collection in this field.Experiments onmulti-sources datasets show that our proposal can achieve as high precision and recall as 95%with a traffic handling throughput of over 106 pps. 展开更多
关键词 Network address translation NAT security NAT identification active measurement
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Measurement of mouse liver glutathione S-transferase activity by the integrated method 被引量:10
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作者 廖飞 李甲初 +2 位作者 康格非 曾昭淳 左渝萍 《Journal of Medical Colleges of PLA(China)》 CAS 2003年第5期295-300,共6页
Objective: The integrated method was investigated to measure Vm/Km of mouse liver glutathione S-transfer-ase (GST) activity on GSH and 7-Cl-4-nitrobenzofurazozan. Methods: Presetting concentration of one substrate twe... Objective: The integrated method was investigated to measure Vm/Km of mouse liver glutathione S-transfer-ase (GST) activity on GSH and 7-Cl-4-nitrobenzofurazozan. Methods: Presetting concentration of one substrate twenty-fold above the other's and taking maximum product absorbance Am as parameter while Km as constant, Vm/Km was obtained by nonlinear fitting of GST reaction curve to the integrated Michaelis-Menten equation In [Am/(Am -Ai)] + Ai/ ( ξ× Km ) = ( Vm/Km )×ti (1). Results: Vm/Km for GST showed slight dependence on initial substrate concentration and data range, but it was resistant to background absorbance, error in reaction origin and small deviation in presetting Km. Vm/Km was proportional to the amount of GST with upper limit higher than that by initial rate. There was close correlation between Vm/Km and initial rate of the same GST. Consistent results were obtained by this integrated method and classical initial rate method for the measurement of mouse liver GST. Conclusion: With the concentration of one substrate twenty-fold above the other's, this integrated method was reliable to measure the activity of enzyme on two substrates , and substrate concentration of the lower one close to its apparent Km was able to be used. 展开更多
关键词 integrated method glutathione S-transferase nonlinear fitting reaction curve predictor variable enzyme activity measurement
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Understanding pollution dynamics in large-scale peer-to-peer IPTV system 被引量:2
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作者 王海舟 陈兴蜀 +1 位作者 王文贤 郝正鸿 《Journal of Central South University》 SCIE EI CAS 2012年第8期2203-2217,共15页
With the great commercial success of several IPTV (internet protocal television) applications, PPLive has received more and more attention from both industry and academia. At present, PPLive system is one of the most ... With the great commercial success of several IPTV (internet protocal television) applications, PPLive has received more and more attention from both industry and academia. At present, PPLive system is one of the most popular instances of IPTV applications which attract a large number of users across the globe; however, the dramatic rise in popularity makes it more likely to become a vulnerable target. The main contribution of this work is twofold. Firstly, a dedicated distributed crawler system was proposed and its crawling performance was analyzed, which was used to evaluate the impact of pollution attack in P2P live streaming system. The measurement results reveal that the crawler system with distributed architecture could capture PPLive overlay snapshots with more efficient way than previous crawlers. To the best of our knowledge, our study work is the first to employ distributed architecture idea to design crawler system and discuss the crawling performance of capturing accurate overlay snapshots for P2P live streaming system. Secondly, a feasible and effective pollution architecture was proposed to deploy content pollution attack in a real-world P2P live streaming system called PPLive, and deeply evaluate the impact of pollution attack from following five aspects:dynamic evolution of participating users, user lifetime characteristics, user connectivity-performance, dynamic evolution of uploading polluted chunks and dynamic evolution of pollution ratio. Specifically, the experiment results show that a single polluter is capable of compromising all the system and its destructiveness is severe. 展开更多
关键词 peer-to-peer technology internet protocol television active measurement distributed crawler pollution attack PPLIVE
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An Overview of Passive and Active Dust Detection Methods Using Satellite Measurements 被引量:4
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作者 陈斌 张鹏 +4 位作者 张北斗 贾瑞 张芝娟 王天河 周天 《Journal of Meteorological Research》 SCIE 2014年第6期1029-1040,共12页
In this paper,the methods to detect dust based on passive and active measurements from satellites have been summarized.These include the visible and infrared(VIR) method,thermal infrared(TIR) method,microwave pola... In this paper,the methods to detect dust based on passive and active measurements from satellites have been summarized.These include the visible and infrared(VIR) method,thermal infrared(TIR) method,microwave polarized index(MPI) method,active lidar-based method,and combined lidar and infrared measurement(CLIM) method.The VIR method can identify dust during daytime.Using measurements at wavelengths of 8.5,11.0,and 12.0 fan,the TIR method can distinguish dust from other types of aerosols and cloud,and identify the occurrence of dust over bright surfaces and during night.Since neither the VIR nor the TIR method can penetrate ice clouds,they cannot detect dust beneath ice clouds.The MPI method,however,can identify about 85%of the dust beneath ice clouds.Meanwhile,the active lidar-based method,which uses the Cloud-Aerosol Lidar with Orthogonal Polarization(CALIOP) data and five-dimensional probability distribution functions,can provide very high-resolution vertical profiles of dust aerosols.Nonetheless,as the signals from dense dust and thin clouds are similar in the CALIOP measurements,the lidar-based method may fail to distinguish between them,especially over dust source regions.To address this issue,the CLIM method was developed,which takes the advantages of both TIR measurements(to discriminate between ice cloud and dense dust layers) and lidar measurements(to detect thin dust and water cloud layers).The results obtained by using the new CLIM method show that the ratio of dust misclassification has been significantly reduced.Finally,a concept module for an integrated multi-satellites dust detection system was proposed to overcome some of the weaknesses inherent in the single-sensor dust detection. 展开更多
关键词 dust detection integrated multi-sensors passive and active measurements
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Lessons from construction and health condition evaluation of high-grade highway in permafrost regions
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作者 JianHong Fang QingZhi Wang KeJin Wang 《Research in Cold and Arid Regions》 CSCD 2021年第5期372-378,共7页
Located in the eastern margin of the Tibetan Plateau,the Gonghe-Yushu high-grade highway was the first of its kind in plateau permafrost regions.Most of the road sections along the high-grade highway are unstable or e... Located in the eastern margin of the Tibetan Plateau,the Gonghe-Yushu high-grade highway was the first of its kind in plateau permafrost regions.Most of the road sections along the high-grade highway are unstable or extremely unstable warm permafrost with an average annual ground temperature above −1℃,which is vulnerable to global warming and human engineering activities.This paper describes permafrost characteristics,roadbed design,and operation of the Gonghe-Yushu high-grade highway in detail.It is found that thaw settlement of warm and ice-rich permafrost is the main cause of subgrade subsidence in permafrost sections of this highway due to insufficient permafrost survey and drainage design.It is recommended that the interception and drainage system's design be optimized,and the permafrost upper limit and the variation of ground temperature be further investigated to provide essential data for the treatment of highway distress.It should be emphasized that protecting permafrost soil environment and optimized engineering design are crucial to successful high-grade highway engineering in permafrost regions. 展开更多
关键词 PERMAFROST high-grade highway active cooling measure DISTRESS
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Variations of the Earth's rotation rate and cyclic processes in geodynamics 被引量:1
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作者 B.W. Levin E.V. Sasorova +3 位作者 G.M. Steblov A.V. Domanski A.S. Prytkov E.N. Tsyba 《Geodesy and Geodynamics》 2017年第3期206-212,共7页
The authors analyzed the relationship between variations of the Earth's rotation rate and the geodynamic processes within the Earth's body, including seismic activity, The rotation rate of a planet determines its un... The authors analyzed the relationship between variations of the Earth's rotation rate and the geodynamic processes within the Earth's body, including seismic activity, The rotation rate of a planet determines its uniaxial compression along the axis of rotation and the areas of various surface elements of the body. The Earth's ellipticity variations, caused naturally by the rotation rate variations, are manifested in vertical components of precise GPS measurements. Comparative analysis of these variations is considered in view of modern theoretical ideas concerning the Earth's figure. The results justify further research that is of interest for improvement of space svstems and technologiesi. 展开更多
关键词 Earth's rotation rate Earth's ellipticity Changes in the planet's figure Seismic activity Pulsations of the vertical components of GPS measurements
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User-perceived e-mail service QoS parameters and measurement
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作者 LI Yong-zhi , LIU Feng, LEI Zhen-ming, CHEN Ling School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2010年第3期85-90,共6页
A group of quality of service (QoS) parameters of electronic mail (e-mail) traffic are proposed from users' perspective. These parameters cover three fields: delay, throughput and usability. Concept and algorith... A group of quality of service (QoS) parameters of electronic mail (e-mail) traffic are proposed from users' perspective. These parameters cover three fields: delay, throughput and usability. Concept and algorithm of each parameter are presented and its effect on user perceptions is described. In order to evaluate the effectiveness of these parameters, an active measurement system is implemented. Measured results show that the group of QoS parameters we proposed can be used to get a comprehensive view of user-perceived e-mail service QoS. 展开更多
关键词 user perceptions e-mail service QOS active measurement
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Determination of the number of atoms of the long-lived nuclide ^(126)Sn by γ-ray spectrometry 被引量:1
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作者 SHEN Hong-Tao JIANG Shan +12 位作者 HE Ming DONG Ke-Jun LI Chao-Li WANG Xiang-Gao HE Guo Zhu GONG Jie LU Li-Yan LI Shi-Zhuo ZHANG Da-Wei SHI Guo-Zhu HUANG Chun-Tang WU Shao-Lei WU Shao-Yong 《Chinese Physics C》 SCIE CAS CSCD 2010年第1期143-147,共5页
By using HPGe γ-ray spectrometry, the activity of the long-lived fission product 126Sn in a SnOB2 sample was measured. The number of 126Sn atoms and the ratio of 126Sn to Sn were calculated based on the half-life val... By using HPGe γ-ray spectrometry, the activity of the long-lived fission product 126Sn in a SnOB2 sample was measured. The number of 126Sn atoms and the ratio of 126Sn to Sn were calculated based on the half-life value of 2.35×105a and the chemical stoichiometry. The result of the ratio of 126Sn to Sn, (1.033±0.037)×10-8, is consistent with the results measured by the accelerator mass spectrometry (AMS) within uncertainty limits, which confirms our procedures in the measurement of 126Sn by AMS and lays a foundation for the AMS measurement of 126Sn at much lower levels. 展开更多
关键词 126Sn activity measurement γ-ray spectrometry AMS
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Chemical synthesis of Ub-AMC via ligation of peptide hydrazides 被引量:3
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作者 LIANG Jun FANG GeMin +4 位作者 HUANG XiuLiang MEI ZiQing LI Juan TIAN ChangLin LIU Lei 《Science China Chemistry》 SCIE EI CAS 2013年第9期1301-1306,共6页
The C-terminal conjugate of ubiquitin with 7-amino-4-methylcoumarin (Ub-AMC) is an important probe for fluorescencebased analysis of deubiquitinating enzyme (DUB) activity. It is important to develop more efficien... The C-terminal conjugate of ubiquitin with 7-amino-4-methylcoumarin (Ub-AMC) is an important probe for fluorescencebased analysis of deubiquitinating enzyme (DUB) activity. It is important to develop more efficient methods for the preparation of Ub-AMC because the currently available technology is still expensive for scaled-up production. In the present work we report an efficient strategy for total chemical synthesis of Ub-AMC through ligation of peptide hydrazides. Three peptide segments are assembled via N-to-C sequential ligation and the resulting product is converted to Ub-AMC via TCEP-mediated desulfurization. The synthetic Ub-AMC is shown to have expected biological functions throug 展开更多
关键词 h the measurement of its DUB activity.ligation of peptide hydrazides peptide segment condensation deubiquitinating enzymes UBIQUITIN
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CLINICAL SIGNIFICANCE OF MEASURING SERUM IL-6 ACTIVITIES IN MULTIPLE MYELOMA AN ANALYSIS OF 81 CASES 被引量:1
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作者 候健 孔宪涛 《Chinese Medical Journal》 SCIE CAS CSCD 1994年第11期70-71,共2页
Interleukin 6(IL-6) is known as hybridoma cell growth factor,B-cell differentiating factor and so on One of its important biological functions in to induce
关键词 IL In CLINICAL SIGNIFICANCE OF MEASURING SERUM IL-6 ACTIVITIES IN MULTIPLE MYELOMA AN ANALYSIS OF 81 CASES
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