期刊文献+
共找到311篇文章
< 1 2 16 >
每页显示 20 50 100
The Research about A Regional Drought Identifying System Based on Dynamic Drought Index 被引量:1
1
作者 王俊 胡继超 +1 位作者 袁学所 吴有华 《Meteorological and Environmental Research》 CAS 2010年第9期94-96,共3页
With the data of daily precipitation and daily evaporation,dynamic drought index was calculated and compared with the identification standard of drought grade to qualify the severity of drought.According to the dynami... With the data of daily precipitation and daily evaporation,dynamic drought index was calculated and compared with the identification standard of drought grade to qualify the severity of drought.According to the dynamic drought index,a regional drought identifying system was developed for the watershed between the reach of the Yangtze River and Huaihe River in Anhui Province by using VC++ working platform and Access database.This drought identifying system would be very useful to forecast and early warn the happening of drought in this area. 展开更多
关键词 Drought Index Drought identifying system Daily precipitation China
下载PDF
Re-identifying beef cattle using improved AlignedReID++
2
作者 YING Xiaoyi ZHAO Jizheng +7 位作者 YANG Lingling ZHOU Xinyi WANG Lei GAO Yannian ZAN Linsen YANG Wucai LIU Han SONG Huaibo 《农业工程学报》 EI CAS CSCD 北大核心 2024年第18期132-146,共15页
Accurate and continuous identification of individual cattle is crucial to precision farming in recent years.It is also the prerequisite to monitor the individual feed intake and feeding time of beef cattle at medium t... Accurate and continuous identification of individual cattle is crucial to precision farming in recent years.It is also the prerequisite to monitor the individual feed intake and feeding time of beef cattle at medium to long distances over different cameras.However,beef cattle can tend to frequently move and change their feeding position during feeding.Furthermore,the great variations in their head direction and complex environments(light,occlusion,and background)can also lead to some difficulties in the recognition,particularly for the bio-similarities among individual cattle.Among them,AlignedReID++model is characterized by both global and local information for image matching.In particular,the dynamically matching local information(DMLI)algorithm has been introduced into the local branch to automatically align the horizontal local information.In this research,the AlignedReID++model was utilized and improved to achieve the better performance in cattle re-identification(ReID).Initially,triplet attention(TA)modules were integrated into the BottleNecks of ResNet50 Backbone.The feature extraction was then enhanced through cross-dimensional interactions with the minimal computational overhead.Since the TA modules in AlignedReID++baseline model increased the model size and floating point operations(FLOPs)by 0.005 M and 0.05 G,the rank-1 accuracy and mean average precision(mAP)were improved by 1.0 percentage points and 2.94 percentage points,respectively.Specifically,the rank-1 accuracies were outperformed by 0.86 percentage points and 0.12 percentage points,respectively,compared with the convolution block attention module(CBAM)and efficient channel attention(ECA)modules,although 0.94 percentage points were lower than that of squeeze-and-excitation(SE)modules.The mAP metric values were exceeded by 0.22,0.86 and 0.12 percentage points,respectively,compared with the SE,CBAM,and ECA modules.Additionally,the Cross-Entropy Loss function was replaced with the CosFace Loss function in the global branch of baseline model.CosFace Loss and Hard Triplet Loss were jointly employed to train the baseline model for the better identification on the similar individuals.AlignedReID++with CosFace Loss was outperformed the baseline model by 0.24 and 0.92 percentage points in the rank-1 accuracy and mAP,respectively,whereas,AlignedReID++with ArcFace Loss was exceeded by 0.36 and 0.56 percentage points,respectively.The improved model with the TA modules and CosFace Loss was achieved in a rank-1 accuracy of 94.42%,rank-5 accuracy of 98.78%,rank-10 accuracy of 99.34%,mAP of 63.90%,FLOPs of 5.45 G,frames per second(FPS)of 5.64,and model size of 23.78 M.The rank-1 accuracies were exceeded by 1.84,4.72,0.76 and 5.36 percentage points,respectively,compared with the baseline model,part-based convolutional baseline(PCB),multiple granularity network(MGN),and relation-aware global attention(RGA),while the mAP metrics were surpassed 6.42,5.86,4.30 and 7.38 percentage points,respectively.Meanwhile,the rank-1 accuracy was 0.98 percentage points lower than TransReID,but the mAP metric was exceeded by 3.90 percentage points.Moreover,the FLOPs of improved model were only 0.05 G larger than that of baseline model,while smaller than those of PCB,MGN,RGA,and TransReID by 0.68,6.51,25.4,and 16.55 G,respectively.The model size of improved model was 23.78 M,which was smaller than those of the baseline model,PCB,MGN,RGA,and TransReID by 0.03,2.33,45.06,14.53 and 62.85 M,respectively.The inference speed of improved model on a CPU was lower than those of PCB,MGN,and baseline model,but higher than TransReID and RGA.The t-SNE feature embedding visualization demonstrated that the global and local features were achieve in the better intra-class compactness and inter-class variability.Therefore,the improved model can be expected to effectively re-identify the beef cattle in natural environments of breeding farm,in order to monitor the individual feed intake and feeding time. 展开更多
关键词 method IDENTIFY beef cattle precision livestock re-identification AlignedReID++ deep learning
下载PDF
Designing a Secure and Scalable Data Sharing Mechanism Using Decentralized Identifiers(DID)
3
作者 Iuon-Chang Lin I-Ling Yeh +2 位作者 Ching-Chun Chang Jui-Chuan Liu Chin-Chen Chang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第10期809-822,共14页
Centralized storage and identity identification methods pose many risks,including hacker attacks,data misuse,and single points of failure.Additionally,existing centralized identity management methods face interoperabi... Centralized storage and identity identification methods pose many risks,including hacker attacks,data misuse,and single points of failure.Additionally,existing centralized identity management methods face interoperability issues and rely on a single identity provider,leaving users without control over their identities.Therefore,this paper proposes a mechanism for identity identification and data sharing based on decentralized identifiers.The scheme utilizes blockchain technology to store the identifiers and data hashed on the chain to ensure permanent identity recognition and data integrity.Data is stored on InterPlanetary File System(IPFS)to avoid the risk of single points of failure and to enhance data persistence and availability.At the same time,compliance with World Wide Web Consortium(W3C)standards for decentralized identifiers and verifiable credentials increases the mechanism’s scalability and interoperability. 展开更多
关键词 Self-sovereign identity decentralized identifier blockchain
下载PDF
Analysis on Genetic Diversity of 40 Flowering Cherry Cultivars and Construction of Molecular ID Based on SSR Markers
4
作者 Chaoren Nie Xiaoguo Xu +3 位作者 Xiaoqin Zhang Hongbing Sun Jingya Yu Wensheng Xia 《Agricultural Sciences》 2024年第2期256-273,共18页
Studying on the genetic diversity and genetic relationship of flowering cherry cultivars is extremely important for germplasm conservation, cultivar identification and breeding. Flowering cherry is widely cultivated a... Studying on the genetic diversity and genetic relationship of flowering cherry cultivars is extremely important for germplasm conservation, cultivar identification and breeding. Flowering cherry is widely cultivated as an important woody ornamental plant in worldwide, especially Japan, China. However, owning to the morphological similarity, many cultivars are distinguished hardly in non-flowering season. Here, we evaluated the genetic diversity and genetic relationship of 40 flowering cherry cultivars, which are mainly cultivated in China. We selected 13 polymorphicprimers to amplify to allele fragments with fluorescent-labeled capillary electrophoresis technology. The population structure analysis results show that these cultivars could be divided into 4 subpopulations. At the population level, N<sub>a</sub> and N<sub>e</sub> were 6.062, 4.326, respectively. H<sub>o</sub> and H<sub>e</sub> were 0.458 and 0.670, respectively. The Shannon’s information index (I) was 1.417. The Pop3, which originated from P. serrulata, had the highest H<sub>o</sub>, H<sub>e</sub>, and I among the 4 subpopulations. AMOVA showed that only 4% of genetic variation came from populations, the 39% variation came from individuals and 57% (p < 0.05) came from intra-individuals. 5 polymorphic SSR primers were selected to construct molecular ID code system of these cultivars. This analysis on the genetic diversity and relationship of the 40 flowering cherry cultivars will help to insight into the genetic background, relationship of these flowering cherry cultivars and promote to identify similar cultivars. 展开更多
关键词 Flowering Cherry SSR Genetic Relationship Molecular ID identifying Cultivars
下载PDF
Analysis of the Influence of Woodcut Works of Anti-Japanese War on the National Spiritual Identity of Young People
5
作者 ZHANG Tong-yuan 《Journal of Literature and Art Studies》 2024年第10期916-920,共5页
As one of the important art forms during the Anti-Japanese War in China, woodcut is not only a tool for literary and artistic workers to express the spirit of Anti-Japanese War, but also a medium to inspire the people... As one of the important art forms during the Anti-Japanese War in China, woodcut is not only a tool for literary and artistic workers to express the spirit of Anti-Japanese War, but also a medium to inspire the people and arouse patriotic feelings. Through a systematic analysis of the historical background and artistic characteristics of woodcuts of the Anti-Japanese War and their impact on the national spiritual identity of young people, this paper aims to explore how woodcuts enlightens and inspires young people’s national consciousness through visual language and spiritual connotation, and enhances their sense of belonging to the country and the nation. 展开更多
关键词 anti-Japanese woodcut national spirit TEENAGERS identify with artistic influence
下载PDF
Ad Blockers & Online Privacy: A Comparative Analysis of Privacy Enhancing Technologies (PET)
6
作者 Siddharth M. Madikeri Vijay K. Madisetti 《Journal of Software Engineering and Applications》 2024年第5期378-395,共18页
Online tracking mechanisms employed by internet companies for user profiling and targeted advertising raise major privacy concerns. Despite efforts to defend against these mechanisms, they continue to evolve, renderin... Online tracking mechanisms employed by internet companies for user profiling and targeted advertising raise major privacy concerns. Despite efforts to defend against these mechanisms, they continue to evolve, rendering many existing defences ineffective. This study performs a large-scale measurement of online tracking mechanisms across a large pool of websites using the OpenWPM (Open Web Privacy Measurement) platform. It systematically evaluates the effectiveness of several ad blockers and underlying Privacy Enhancing Technologies (PET) that are primarily used to mitigate different tracking techniques. By quantifying the strengths and limitations of these tools against modern tracking methods, the findings highlight gaps in existing privacy protections. Actionable recommendations are provided to enhance user privacy defences, guide tool developers and inform policymakers on addressing invasive online tracking practices. 展开更多
关键词 Privacy Enhancing Technology (PET) Personally Identifiable Information (PII) OpenWPM Web Privacy
下载PDF
A circular zone counting method of identifying a Duffing oscillator state transition and determining the critical value in weak signal detection 被引量:3
7
作者 李梦平 许雪梅 +1 位作者 杨兵初 丁家峰 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第6期192-197,共6页
Identifying state transition and determining the critical value of the Duffing oscillator are crucial to indicating external signal existence and have a great influence on detection accuracy in weak signal detection. ... Identifying state transition and determining the critical value of the Duffing oscillator are crucial to indicating external signal existence and have a great influence on detection accuracy in weak signal detection. A circular zone counting (CZC) method is proposed in this paper, by combining the Duffing oscillator's phase trajectory feature and numerical calculation for quickly and accurately identifying state transition and determining the critical value, to realize a high- efficiency weak signal detection. Detailed model analysis and method construction of the CZC method are introduced. Numerical experiments into the reliability of the proposed CZC method compared with the maximum Lyapunov exponent (MLE) method are carried out. The CZC method is demonstrated to have better detecting ability than the MLE method, and furthermore it is simpler and clearer in calculation to extend to engineering application. 展开更多
关键词 identifying state transition determining critical value Duffing oscillator circular zone countingmethod maximum Lyapunov exponent method
下载PDF
THE QUASI-BOUNDARY VALUE METHOD FOR IDENTIFYING THE INITIAL VALUE OF THE SPACE-TIME FRACTIONAL DIFFUSION EQUATION 被引量:3
8
作者 Fan YANG Yan ZHANG +1 位作者 Xiao LIU Xiaoxiao LI 《Acta Mathematica Scientia》 SCIE CSCD 2020年第3期641-658,共18页
In this article,we consider to solve the inverse initial value problem for an inhomogeneous space-time fractional diffusion equation.This problem is ill-posed and the quasi-boundary value method is proposed to deal wi... In this article,we consider to solve the inverse initial value problem for an inhomogeneous space-time fractional diffusion equation.This problem is ill-posed and the quasi-boundary value method is proposed to deal with this inverse problem and obtain the series expression of the regularized solution for the inverse initial value problem.We prove the error estimates between the regularization solution and the exact solution by using an a priori regularization parameter and an a posteriori regularization parameter choice rule.Some numerical results in one-dimensional case and two-dimensional case show that our method is efficient and stable. 展开更多
关键词 Space-time fractional diffusion equation Ill-posed problem quasi-boundary value method identifying the initial value
下载PDF
Identification of variable coefficients for vibrating systems by boundary control and observation 被引量:2
9
作者 Jinde CHANG 《控制理论与应用(英文版)》 EI 2008年第2期127-132,共6页
We consider the identification problem of coefficients for vibrating systems described by a Euler-Bernoulli beam eq~. ation Or a string equation, with one end clamped and with an input exerted on the other end. For th... We consider the identification problem of coefficients for vibrating systems described by a Euler-Bernoulli beam eq~. ation Or a string equation, with one end clamped and with an input exerted on the other end. For the beam equation, the observations are the velocity and the angle velocity at the free end, while for the string equation, the observation is the velocity at the free end. In the framework of well-posed linear system theory, we show that both the density and the flexural rigidity of the beam, and the tension of the string, can be uniquely determined by the observations for all positive times. Moreover, a general constructive method is developed to show that the mass density and the elastic modulus of the string are not determined by the observation. 展开更多
关键词 Beam equation IDENTIFIABILITY WELL-POSEDNESS Variable coefficients Inverse problem
下载PDF
Sliding mode identifier for parameter uncertain nonlinear dynamic systems with nonlinear input 被引量:2
10
作者 张克勤 庄开宇 +2 位作者 苏宏业 褚健 高红 《Journal of Zhejiang University Science》 CSCD 2002年第4期426-430,共5页
This paper presents a sliding mode (SM) based identifier to deal with the parameter identification problem for a class of parameter uncertain nonlinear dynamic systems with input nonlinearity. A sliding mode controlle... This paper presents a sliding mode (SM) based identifier to deal with the parameter identification problem for a class of parameter uncertain nonlinear dynamic systems with input nonlinearity. A sliding mode controller (SMC) is used to ensure the global reaching condition of the sliding mode for the nonlinear system; an identifier is designed to identify the uncertain parameter of the nonlinear system. A numerical example is studied to show the feasibility of the SM controller and the asymptotical convergence of the identifier. 展开更多
关键词 Nonlinear system Sliding mode IDENTIFIER Input nonlinearity
下载PDF
Anterior segment optical coherence tomography for identifying muscle status in strabismus surgery 被引量:2
11
作者 Brijesh Takkar Pradeep Sharma +1 位作者 Ashutosh Kummar Singh Pranita Sahay 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2016年第6期933-934,共2页
Anterior segment optical coherence tomography (AS-OCT) finds very few indications in the domain of strabismus surgery. Current applications remain restricted to determining limbus-muscle insertion distance and anter... Anterior segment optical coherence tomography (AS-OCT) finds very few indications in the domain of strabismus surgery. Current applications remain restricted to determining limbus-muscle insertion distance and anterior segment changes after strabismus surgery. We discuss two cases of operated strabismus surgery where AS-OCT imaging helped in identifying the operated eye and/or extra ocular muscles (EOM) and thus proved instrumental in planning and management. 展开更多
关键词 AS Anterior segment optical coherence tomography for identifying muscle status in strabismus surgery
下载PDF
Efficient Security Multimedia System on Embedded Platform 被引量:1
12
作者 WANG Lifeng MENG Qinglei +3 位作者 XIAO Chen MA Jian DU Yaogang WANG Wendong 《China Communications》 SCIE CSCD 2010年第4期120-125,共6页
Security video communication is a challenging task,especially for wireless video applications.An efficient security multimedia system on embedded platform is designed.By analyzing the hardware architecture and resourc... Security video communication is a challenging task,especially for wireless video applications.An efficient security multimedia system on embedded platform is designed.By analyzing the hardware architecture and resource,the efficient DSP-based H.264/AVC coding is studied by efficient video coding techniques and system optimizing implementation.To protect the confidentiality and integrity of media information,a novel security mechanism is presented,which includes user identify authentication and a perceptual video encryption algorithm based on exploiting the special feature of entropy coding in H.264.Experimental results show that the proposed hardware framework has high performance and achieves a better balance between security and efficiency.The proposed security mechanism can achieve high security and low complexity cost,and has a little effect on the compression ratio and transmission bandwidth.What’s more,encoding and encryption at the same time,the performance of data process can meet real-time application. 展开更多
关键词 H.264/AVC Encode Optimizing ENCRYPTION Identify Authentication
下载PDF
Heterogeneity in the regenerative abilities of central nervous system axons within species: why do some neurons regenerate better than others? 被引量:1
13
作者 William Rodemer Jianli Hu +1 位作者 Michael E.Selzer Michael I.Shifman 《Neural Regeneration Research》 SCIE CAS CSCD 2020年第6期996-1005,共10页
Some neurons,especially in mammalian peripheral nervous system or in lower vertebrate or in vertebrate central nervous system(CNS)regenerate after axotomy,while most mammalian CNS neurons fail to regenerate.There is a... Some neurons,especially in mammalian peripheral nervous system or in lower vertebrate or in vertebrate central nervous system(CNS)regenerate after axotomy,while most mammalian CNS neurons fail to regenerate.There is an emerging consensus that neurons have different intrinsic regenerative capabilities,which theoretically could be manipulated therapeutically to improve regeneration.Population-based comparisons between"good regenerating"and"bad regenerating"neurons in the CNS and peripheral nervous system of most vertebrates yield results that are inconclusive or difficult to interpret.At least in part,this reflects the great diversity of cells in the mammalian CNS.Using mammalian nervous system imposes several methodical limitations.First,the small sizes and large numbers of neurons in the CNS make it very difficult to distinguish regenerating neurons from non-regenerating ones.Second,the lack of identifiable neurons makes it impossible to correlate biochemical changes in a neuron with axonal damage of the same neuron,and therefore,to dissect the molecular mechanisms of regeneration on the level of single neurons.This review will survey the reported responses to axon injury and the determinants of axon regeneration,emphasizing non-mammalian model organisms,which are often under-utilized,but in which the data are especially easy to interpret. 展开更多
关键词 AXONAL regeneration identifiable NEURONS intrinsic factors LAMPREY Mauthner CELL Müller CELL neuronal death non-mammalian model organisms spinal cord injury zebrafish
下载PDF
Virtual test system for permanent-magnet DC motor 被引量:1
14
作者 崔淑梅 王悦 +3 位作者 柴凤 吴红星 刘宝廷 程树康 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2003年第2期200-204,共5页
In order to obtain the primary parameters and operating characteristics of a DC motor without directly measuring its torque and rational speed, it is proposed to use a PC and a data acquisition card to acquire both th... In order to obtain the primary parameters and operating characteristics of a DC motor without directly measuring its torque and rational speed, it is proposed to use a PC and a data acquisition card to acquire both the dynamic and static data of armature current to establish the performance of a DC permanent magnet motor. The accuracy and validity of this virtual test system proposed were verified by comparing the measurements made with the system proposed with the measurements made with conventional torque meters. It is concluded from the results of comparison that from the mathematic model established for the DC permant magnet motors, both major parameters and operating characteristics can be directly established for the DC motors without measuring their torques and rotational speed, a perfect on line measurement and test system has been established for the DC permanent magnet motors using the theory of virtual test system. The system proposed features shorter test time, higher efficiency and lower cost. 展开更多
关键词 virtual system MOTOR test parameter identify
下载PDF
ADJACENT MARTIX METHOD OF IDENTIFYING ISOMORPHISM TO PLANAR KINEMATIC CHAIN WITH MULTIPLE JOINTS AND HIGHER PAIRS 被引量:2
15
作者 SONG Li HUANG Yong CHENG Ling 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2006年第4期605-609,共5页
The adjacent matrix method for identifying isomorphism to planar kinematic chain with multiple joints and higher pairs is presented. The topological invariants of the planar kinematic chain can be calculated and compa... The adjacent matrix method for identifying isomorphism to planar kinematic chain with multiple joints and higher pairs is presented. The topological invariants of the planar kinematic chain can be calculated and compared by adjacent matrix. The quantity of calculation can be reduced effectively using the several divisions of bars and the reconfiguration of the adjacent matrix. As two structural characteristics of adjacent matrix, the number of division and division code are presented. It can be identified that two kinematic chains are isomorphic or not by comparing the structural characteristics of their adjacent matrixes using a method called matching row-to-row. This method may be applied to the planar linkage chain too. So, the methods of identifying isomorphism are unified in the planar kinematic chain that has or hasn't higher pairs with or without multiple joints. And it has some characters such as visual, simple and convenient for processing by computer, and so on. 展开更多
关键词 Planar kinematic chain Higher pair Multiple joint Adjacent matrix identifying isomorphism
下载PDF
ID-TIMS U-Pb Geochronology of the Tayatea Dyke Swarm of Australia: Identifying Tasmania's Nearest Neighbours in the Proterozoic
16
作者 Charmaine MCGREGOR Steven DENYSZYN +3 位作者 Galen HALVERSON John EVERARD Grace CUMMING Clive CALVER 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2016年第S1期38-,共1页
The Tayatea Dyke Swarm(also known as the Tayatea Dolerite)comprises well-exposed northeast-trending tholeiitic dykes that intrude the Rocky Cape Group(RCG)of northwest Tasmania,Australia.The dykes commonly
关键词 TIMS PB identifying Tasmania’s Nearest Neighbours in the Proterozoic ID-TIMS U-Pb Geochronology of the Tayatea Dyke Swarm of Australia
下载PDF
Kalman filter of the force signal of identifying weld seam in remote teaching
17
作者 刘立君 朱荣华 +2 位作者 张广军 高洪明 吴林 《China Welding》 EI CAS 2008年第2期58-62,共5页
For reasons of the vibration of robot, the rough surface of weld seam and electromagnetic disturbance of welding machine, the force signals of identifying weld seam become unstable. The position error of remote teachi... For reasons of the vibration of robot, the rough surface of weld seam and electromagnetic disturbance of welding machine, the force signals of identifying weld seam become unstable. The position error of remote teaching point is too big to meet teaching requirements in remote welding. The force signals of identifying weld seam can be filtered by Kalman. The force signals of identifying weld seam of next teaching point is accurately predicted according to predicting algorithms, such as the equation of the state, the equation of the observation, the gain matrix of the filter and the covariance matrix of predicting state. The experimental results show that the precision of identifying weld seam is improved by Kalman.filter. 展开更多
关键词 remote teaching Kalman filter identifying weld seam force signal
下载PDF
State-shared model for multiple-input multiple-output systems
18
作者 Zhenhua TIAN Karlene A. HOO 《控制理论与应用(英文版)》 EI 2005年第4期348-356,共9页
This work proposes a method to construct a state-shared model for multiple-input multiple-output (MIMO) systems. A state-shared model is defined as a linear time invariant state-space structure that is driven by mea... This work proposes a method to construct a state-shared model for multiple-input multiple-output (MIMO) systems. A state-shared model is defined as a linear time invariant state-space structure that is driven by measurement signals-the plant outputs and the manipulated variables, but shared by different multiple input/output models. The genesis of the state-shared model is based on a particular reduced non minimal realization. Any such realization necessarily fulfills the requirement that the output of the state-shared model is an asymptotically correct estimate of the output of the plant, if the process model is selected appropriately. The approach is demomtrated on a nonlinear MIMO system - a physiological model of calcium fluxes that controls muscle contraction and relaxation in human cardiac myocytes. 展开更多
关键词 Adaptive identifier Reduced-order model Multiple models Calcium fluxes MYOCYTES
下载PDF
Bending-Torsional Coupled Vibration Test of Large Power Gear Transmission System
19
作者 刘辉 项昌乐 +1 位作者 孙恬恬 蔡仲昌 《Journal of Beijing Institute of Technology》 EI CAS 2010年第4期411-415,共5页
In order to test the bending-torsional coupled vibration characteristics of the multi-shafts gear transmission system of large power vehicles,a torsional vibration exciter was used to apply torsional excitation on the... In order to test the bending-torsional coupled vibration characteristics of the multi-shafts gear transmission system of large power vehicles,a torsional vibration exciter was used to apply torsional excitation on the gear transmission systems and thirty-two acceleration sensors were used to measure the tangential acceleration of each shaft.Torsional vibration signals and bending vibration signals of each measuring point were obtained by calculation of the four-point-response signal.The modal parameters of gear transmission systems including nature frequency,modal shape and modal damping ratio were obtained by identifying modal parameters of the torsional vibration signal and bending vibration signal.The characteristic of the bending vibration and torsional vibration of the gear systems were studied through the analysis of the nature frequency and modal shape.The nonlinearity characteristic of the gear transmission system was investigated through single frequency excitation test,which can be the foundation for further nonlinearity research. 展开更多
关键词 bending-torsional coupled gear transmission system modal parameters identify NONLINEARITY
下载PDF
FUZZY IDENTIFIER WITH EXPONENTIAL RATE OF CONVERGENCE FOR NONLINEAR DYNAMIC SYSTEMS
20
作者 解学军 张克梅 《Acta Mathematica Scientia》 SCIE CSCD 2000年第4期542-550,共9页
In this paper, fuzzy systems are used as identifiers for unknown nonlinear dynamic systems. The fuzzy identifier can incorporate linguistic knowledge of nonlinear dynamic systems with input-output pairs directly into ... In this paper, fuzzy systems are used as identifiers for unknown nonlinear dynamic systems. The fuzzy identifier can incorporate linguistic knowledge of nonlinear dynamic systems with input-output pairs directly into the design. In the case where there is the modelling error, a new identification algorithm is proposed. It is proved that the fuzzy identifier is globally stable and the identification error converges to zero exponentially fast. 展开更多
关键词 Fuzzy identifier nonlinear systems σ-modification algorithm
下载PDF
上一页 1 2 16 下一页 到第
使用帮助 返回顶部