Traditional modal parameter identifi cation methods have many disadvantages,especially when used for processing nonlinear and non-stationary signals.In addition,they are usually not able to accurately identify the dam...Traditional modal parameter identifi cation methods have many disadvantages,especially when used for processing nonlinear and non-stationary signals.In addition,they are usually not able to accurately identify the damping ratio and damage.In this study,methods based on the Hilbert-Huang transform(HHT) are investigated for structural modal parameter identifi cation and damage diagnosis.First,mirror extension and prediction via a radial basis function(RBF) neural network are used to restrain the troublesome end-effect issue in empirical mode decomposition(EMD),which is a crucial part of HHT.Then,the approaches based on HHT combined with other techniques,such as the random decrement technique(RDT),natural excitation technique(NExT) and stochastic subspace identifi cation(SSI),are proposed to identify modal parameters of structures.Furthermore,a damage diagnosis method based on the HHT is also proposed.Time-varying instantaneous frequency and instantaneous energy are used to identify the damage evolution of the structure.The relative amplitude of the Hilbert marginal spectrum is used to identify the damage location of the structure.Finally,acceleration records at gauge points from shaking table testing of a 12-story reinforced concrete frame model are taken to validate the proposed approaches.The results show that the proposed approaches based on HHT for modal parameter identifi cation and damage diagnosis are reliable and practical.展开更多
In this paper,the author defined the interpretation system of geoparks,studied the designing princeples and methods of the interpretation identification system,including the information,content and appearance. Further...In this paper,the author defined the interpretation system of geoparks,studied the designing princeples and methods of the interpretation identification system,including the information,content and appearance. Furthermore,the designing of the interpretation identification system designing of the Hanas National Geopark was conducted as an empirical study,展开更多
Introduction Cationic starches are a series of products of which various sorts with different properties and usages can all be produced via cationic reactions by using different types of etherification agents under di...Introduction Cationic starches are a series of products of which various sorts with different properties and usages can all be produced via cationic reactions by using different types of etherification agents under different conditions. As an additive and strengthening agent,展开更多
Emergency physicians are often the first providersto encounter patients with complications in earlypregnancy. Point-of-care （POC） pelvic ultrasound isbeing increasingly used in the evaluation of emergencydepartment ...Emergency physicians are often the first providersto encounter patients with complications in earlypregnancy. Point-of-care （POC） pelvic ultrasound isbeing increasingly used in the evaluation of emergencydepartment （ED） patients with first trimester symptoms.[1]While the initial aim of POC ultrasound in this settingis to confirm an intrauterine pregnancy, a secondarygoal is to differentiate between a normal and abnormalpregnancy. There exist a number of sonographic featuresto suggest a pregnancy is non-viable.展开更多
The purpose of this review is to apply geometric frameworks in identification problems. In contrast to the qualitative theory of dynamical systems (DSQT), the chaos and catastrophes, researches on the application of g...The purpose of this review is to apply geometric frameworks in identification problems. In contrast to the qualitative theory of dynamical systems (DSQT), the chaos and catastrophes, researches on the application of geometric frameworks have not </span><span style="font-family:Verdana;">been </span><span style="font-family:Verdana;">performed in identification problems. The direct transfer of DSQT ideas is inefficient through the peculiarities of identification systems. In this paper, the attempt </span><span style="font-family:Verdana;">is </span><span style="font-family:Verdana;">made based on the latest researches in this field. A methodology for the synthesis of geometric frameworks (GF) </span><span style="font-family:Verdana;">is </span><span style="font-family:Verdana;">propose</span><span style="font-family:Verdana;">d</span><span style="font-family:Verdana;">, which reflects features of nonlinear systems. Methods based on GF analysis </span><span style="font-family:Verdana;">are </span><span style="font-family:Verdana;">developed for the decision-making on properties and structure of nonlinear systems. The problem solution of structural identifiability </span><span style="font-family:Verdana;">is </span><span style="font-family:Verdana;">obtain</span><span style="font-family:Verdana;">ed</span><span style="font-family:Verdana;"> for nonlinear systems under uncertainty.展开更多
This paper deals with the preparation of cationic starch with high degree of substitute by dry-process. The corn starch and the alkali catalyst are mixed in the mixer, then added the cationic etherifying agent (3-chlo...This paper deals with the preparation of cationic starch with high degree of substitute by dry-process. The corn starch and the alkali catalyst are mixed in the mixer, then added the cationic etherifying agent (3-chloro-2-hydroxypropyltrimethylammonium chloride). The reacting time is for 5 hours at the temperature of 70℃. The cationic starch with high degree of substitution is used as anionic charge neutralizing agents to improve filler retention in wet-end section of papermaking machine.展开更多
网络流量识别是网络管理和安全服务的基础.随着互联网的不断扩展及其复杂性的增加,传统基于规则的识别方法或流行为特征的方法正在面临着巨大挑战.受自然语言处理(Nature Language Processing, NLP)启发,本文提出了一种多特征融合的加...网络流量识别是网络管理和安全服务的基础.随着互联网的不断扩展及其复杂性的增加,传统基于规则的识别方法或流行为特征的方法正在面临着巨大挑战.受自然语言处理(Nature Language Processing, NLP)启发,本文提出了一种多特征融合的加密流量快速分类方法 .该方法通过融合数据包和字节序列特征来完成网络流的特征表示,采用双元字节编码将所选特征扩展为双字节序列,增加了字节的上下文语义特征;通过与数据包特征处理相适应的池化方法来最大限度保留数据包的特征信息,从而使所提模型具有更强的抗噪能力和更精确的分类能力.本文方法分别在ISCX-2016和一个包含66个热门应用程序的私有数据集(ETD66)上进行验证,并与其他模型展开比较.结果表明:本文所提方法在ISCX-2016及ETD66上的测试精度和性能都明显优于其他流量分类模型,分别取得了98.2%和98.6%的识别准确率,从而证明了所提方法的特征提取能力和强泛化能力.展开更多
基金Gansu Science and Technology Key Project under Grant No.2GS057-A52-008
文摘Traditional modal parameter identifi cation methods have many disadvantages,especially when used for processing nonlinear and non-stationary signals.In addition,they are usually not able to accurately identify the damping ratio and damage.In this study,methods based on the Hilbert-Huang transform(HHT) are investigated for structural modal parameter identifi cation and damage diagnosis.First,mirror extension and prediction via a radial basis function(RBF) neural network are used to restrain the troublesome end-effect issue in empirical mode decomposition(EMD),which is a crucial part of HHT.Then,the approaches based on HHT combined with other techniques,such as the random decrement technique(RDT),natural excitation technique(NExT) and stochastic subspace identifi cation(SSI),are proposed to identify modal parameters of structures.Furthermore,a damage diagnosis method based on the HHT is also proposed.Time-varying instantaneous frequency and instantaneous energy are used to identify the damage evolution of the structure.The relative amplitude of the Hilbert marginal spectrum is used to identify the damage location of the structure.Finally,acceleration records at gauge points from shaking table testing of a 12-story reinforced concrete frame model are taken to validate the proposed approaches.The results show that the proposed approaches based on HHT for modal parameter identifi cation and damage diagnosis are reliable and practical.
文摘In this paper,the author defined the interpretation system of geoparks,studied the designing princeples and methods of the interpretation identification system,including the information,content and appearance. Furthermore,the designing of the interpretation identification system designing of the Hanas National Geopark was conducted as an empirical study,
文摘Introduction Cationic starches are a series of products of which various sorts with different properties and usages can all be produced via cationic reactions by using different types of etherification agents under different conditions. As an additive and strengthening agent,
文摘Emergency physicians are often the first providersto encounter patients with complications in earlypregnancy. Point-of-care （POC） pelvic ultrasound isbeing increasingly used in the evaluation of emergencydepartment （ED） patients with first trimester symptoms.[1]While the initial aim of POC ultrasound in this settingis to confirm an intrauterine pregnancy, a secondarygoal is to differentiate between a normal and abnormalpregnancy. There exist a number of sonographic featuresto suggest a pregnancy is non-viable.
文摘The purpose of this review is to apply geometric frameworks in identification problems. In contrast to the qualitative theory of dynamical systems (DSQT), the chaos and catastrophes, researches on the application of geometric frameworks have not </span><span style="font-family:Verdana;">been </span><span style="font-family:Verdana;">performed in identification problems. The direct transfer of DSQT ideas is inefficient through the peculiarities of identification systems. In this paper, the attempt </span><span style="font-family:Verdana;">is </span><span style="font-family:Verdana;">made based on the latest researches in this field. A methodology for the synthesis of geometric frameworks (GF) </span><span style="font-family:Verdana;">is </span><span style="font-family:Verdana;">propose</span><span style="font-family:Verdana;">d</span><span style="font-family:Verdana;">, which reflects features of nonlinear systems. Methods based on GF analysis </span><span style="font-family:Verdana;">are </span><span style="font-family:Verdana;">developed for the decision-making on properties and structure of nonlinear systems. The problem solution of structural identifiability </span><span style="font-family:Verdana;">is </span><span style="font-family:Verdana;">obtain</span><span style="font-family:Verdana;">ed</span><span style="font-family:Verdana;"> for nonlinear systems under uncertainty.
文摘This paper deals with the preparation of cationic starch with high degree of substitute by dry-process. The corn starch and the alkali catalyst are mixed in the mixer, then added the cationic etherifying agent (3-chloro-2-hydroxypropyltrimethylammonium chloride). The reacting time is for 5 hours at the temperature of 70℃. The cationic starch with high degree of substitution is used as anionic charge neutralizing agents to improve filler retention in wet-end section of papermaking machine.
文摘网络流量识别是网络管理和安全服务的基础.随着互联网的不断扩展及其复杂性的增加,传统基于规则的识别方法或流行为特征的方法正在面临着巨大挑战.受自然语言处理(Nature Language Processing, NLP)启发,本文提出了一种多特征融合的加密流量快速分类方法 .该方法通过融合数据包和字节序列特征来完成网络流的特征表示,采用双元字节编码将所选特征扩展为双字节序列,增加了字节的上下文语义特征;通过与数据包特征处理相适应的池化方法来最大限度保留数据包的特征信息,从而使所提模型具有更强的抗噪能力和更精确的分类能力.本文方法分别在ISCX-2016和一个包含66个热门应用程序的私有数据集(ETD66)上进行验证,并与其他模型展开比较.结果表明:本文所提方法在ISCX-2016及ETD66上的测试精度和性能都明显优于其他流量分类模型,分别取得了98.2%和98.6%的识别准确率,从而证明了所提方法的特征提取能力和强泛化能力.
