A complete geometric nonlinear formulation for rigid-flexible coupling dynamics of a flexible beam undergoing large overall motion was proposed based on virtual work principle, in which all the high-order terms relate...A complete geometric nonlinear formulation for rigid-flexible coupling dynamics of a flexible beam undergoing large overall motion was proposed based on virtual work principle, in which all the high-order terms related to coupling deformation were included in dynamic equations. Simulation examples of the flexible beam with prescribed rotation and free rotation were investigated. Numerical results show that the use of the first-order approximation coupling (FOAC) model may lead to a significant error when the flexible beam experiences large deformation or large deformation velocity. However, the correct solutions can always be obtained by using the present complete model. The difference in essence between this model and the FOAC model is revealed. These coupling high-order terms, which are ignored in FOAC model, have a remarkable effect on the dynamic behavior of the flexible body. Therefore, these terms should be included for the rigid-flexible dynamic modeling and analysis of flexible body undergoing motions with high speed.展开更多
Linux has a special feature of automount in the Linux kernel. Filesystem can be mounted and unmounted automatically. Its performance is similar to MS Windows. It works well under demands of more saving resources and a...Linux has a special feature of automount in the Linux kernel. Filesystem can be mounted and unmounted automatically. Its performance is similar to MS Windows. It works well under demands of more saving resources and automatization, like memory of system. An approach to install/update software automatically on embedded platform was proposed. This approach derives from above feature based on embedded environment with Linux OS. Configurations of files related to this feature were introduced. An example in practice was given to realize this approach from universal serial bus (USB) memory disk when USB disk is available.展开更多
The depth from extreme points(DEXP)method can be used for estimating source depths and providing a rough image as a starting model for inversion.However,the application of the DEXP method is limited by the lack of pri...The depth from extreme points(DEXP)method can be used for estimating source depths and providing a rough image as a starting model for inversion.However,the application of the DEXP method is limited by the lack of prior information regarding the structural index.Herein,we describe an automatic DEXP method derived from Euler’s Homogeneity equation,and we call it the Euler–DEXP method.We prove that its scaling field is independent of structural indices,and the scaling exponent is a constant for any potential field or its derivative.Therefore,we can simultaneously estimate source depths with diff erent geometries in one DEXP image.The implementation of the Euler–DEXP method is fully automatic.The structural index can be subsequently determined by utilizing the estimated depth.This method has been tested using synthetic cases with single and multiple sources.All estimated solutions are in accordance with theoretical source parameters.We demonstrate the practicability of the Euler–DEXP method with the gravity field data of the Hastings Salt Dome.The results ultimately represent a better understanding of the geometry and depth of the salt dome.展开更多
Based on electromagnetics and mechanics, electromechanical coupled dynamic equations for the drive were developed. Using method of perturbation, free vibrations of the mechanical system under electric disturbance were...Based on electromagnetics and mechanics, electromechanical coupled dynamic equations for the drive were developed. Using method of perturbation, free vibrations of the mechanical system under electric disturbance were investigated. The forced responses of the mechanical system to mechanical excitation under electric disturbance were also presented. It is known that for the system with electric disturbance, as time grows, beat occurs. When electric disturbing frequency is near to the natural frequencies of the mechanical system or their integer multiple, resonance vibrations occur. The forced responses of the mechanical system to mechanical excitation under electric disturbance are compound vibrations decided by mechanical excitation, electric disturbance and parameters of the system. The coupled resonance vibration caused by electric disturbance and mechanical excitation was discussed as well. The conditions under which above coupled resonance occurs were presented. The results show that when the difference of the excitation frequency and the perturbation frequency is equal to some order of natural frequency, coupled resonance vibrations occur.展开更多
Academic research into service industries has explored the characteristics of interpersonal interactions between employees and customers, but there are few studies addressing the issues of consumer interaction with te...Academic research into service industries has explored the characteristics of interpersonal interactions between employees and customers, but there are few studies addressing the issues of consumer interaction with technology and its influence on the objectives and results of the operations subsystem. This study examines the elements of the service encounter, and the changes automation originates in them and their relationships. The paper also examines changes in the elements and results of the operations subsystem, as a result of automation. We propose that the customer's relationship with employees and/or technology and automated systems for the service impact the objectives and results of the operations subsystem, all of which could have an effect on the company's competitive position. The empirical study is focused on four industries, namely, toll motorways, car parks, carwash and video/DVD rental companies, in an attempt to identify objectives that lead companies to implement automated processes affecting the customer's relationship with the company. The hypotheses generated are contrasted with a structural equation modelling. The results confirm that the customer's relationship with employees and automated systems for the service impacts the objectives and results of the operations subsystem. Also, the results show how automation can enable firms simultaneously to achieve acceptable levels of flexibility and productivity, two dimensions that have traditionally been considered opposites.展开更多
In order to solve the problem of vibration bounce caused by the contact between moving and stationary contacts in the process of switching on,two-degree-of-freedom motion differential equation of the contact system is...In order to solve the problem of vibration bounce caused by the contact between moving and stationary contacts in the process of switching on,two-degree-of-freedom motion differential equation of the contact system is established.Genetic algorithm is used to optimize the pull in process of AC contactor.The whole process of contact bounce was observed and analyzed by high-speed photography experiment.The theory and experimental results were very similar.The iron core has collided before the contact is separated,which further aggravates the contact bounce.When the iron core bounces collided again,the bounce of the contact was not affected.During the operation of the contactor,the movement of the moving iron core will cause slight vibration of the system.The contact bounce time and the maximum amplitude are reduced.The research results provide a theoretical basis for further control and reduction of contact bounce.展开更多
Checking whether a given formula is an invariant at a given program location(especially,inside a loop) can be quite nontrivial even for simple loop programs,given that it is in general an undecidable property.This is ...Checking whether a given formula is an invariant at a given program location(especially,inside a loop) can be quite nontrivial even for simple loop programs,given that it is in general an undecidable property.This is especially the case if the given formula is not an inductive loop invariant,as most automated techniques can only check or generate inductive loop invariants.In this paper,conditions are identified on simple loops and formulas when this check can be performed automatically.A general theorem is proved which gives a necessary and sufficient condition for a formula to be an invariant under certain restrictions on a loop.As a byproduct of this analysis,a new kind of loop invariant inside the loop body,called inside-loop invariant,is proposed.Such an invariant is more general than an inductive loop invariant typically used in the Floyd-Hoare axiomatic approach to program verification.The use of such invariants for program debugging is explored;it is shown that such invariants can be more useful than traditional inductive loop invariants especially when one is interested in checking extreme/side conditions such as underflow,accessing array/collection data structures outside the range,divide by zero,etc.展开更多
This paper describes a non-linear information dynamics model for integrated risk assessment of complex disaster system from an evolution perspective. According to the occurrence and evolution of natural disaster syste...This paper describes a non-linear information dynamics model for integrated risk assessment of complex disaster system from an evolution perspective. According to the occurrence and evolution of natural disaster system with complicated and nonlinear characteristics, a non-linear information dynamics mode is introduced based on the maximum flux principle during modeling process to study the integrated risk assessment of complex disaster system. Based on the non-equilibrium statistical mechanics method, a stochastic evolution equation of this system is established. The integrated risk assessment of complex disaster system can be achieved by giving reasonable weights of each evaluation index to stabilize the system. The new model reveals the formation pattern of risk grade and the dynamics law of evolution. Meanwhile, a method is developed to solve the dynamics evolution equations of complex system through the self-organization feature map algorithm. The proposed method has been used in complex disaster integrated risk assessment for 31 provinces, cities and autonomous regions in China mainland. The results have indicated that the model is objective and effective.展开更多
基金Project(10772113) supported by the National Natural Science Foundation of China
文摘A complete geometric nonlinear formulation for rigid-flexible coupling dynamics of a flexible beam undergoing large overall motion was proposed based on virtual work principle, in which all the high-order terms related to coupling deformation were included in dynamic equations. Simulation examples of the flexible beam with prescribed rotation and free rotation were investigated. Numerical results show that the use of the first-order approximation coupling (FOAC) model may lead to a significant error when the flexible beam experiences large deformation or large deformation velocity. However, the correct solutions can always be obtained by using the present complete model. The difference in essence between this model and the FOAC model is revealed. These coupling high-order terms, which are ignored in FOAC model, have a remarkable effect on the dynamic behavior of the flexible body. Therefore, these terms should be included for the rigid-flexible dynamic modeling and analysis of flexible body undergoing motions with high speed.
文摘Linux has a special feature of automount in the Linux kernel. Filesystem can be mounted and unmounted automatically. Its performance is similar to MS Windows. It works well under demands of more saving resources and automatization, like memory of system. An approach to install/update software automatically on embedded platform was proposed. This approach derives from above feature based on embedded environment with Linux OS. Configurations of files related to this feature were introduced. An example in practice was given to realize this approach from universal serial bus (USB) memory disk when USB disk is available.
基金supported by the National Natural Science Foundation of China (Grant No.42176186).
文摘The depth from extreme points(DEXP)method can be used for estimating source depths and providing a rough image as a starting model for inversion.However,the application of the DEXP method is limited by the lack of prior information regarding the structural index.Herein,we describe an automatic DEXP method derived from Euler’s Homogeneity equation,and we call it the Euler–DEXP method.We prove that its scaling field is independent of structural indices,and the scaling exponent is a constant for any potential field or its derivative.Therefore,we can simultaneously estimate source depths with diff erent geometries in one DEXP image.The implementation of the Euler–DEXP method is fully automatic.The structural index can be subsequently determined by utilizing the estimated depth.This method has been tested using synthetic cases with single and multiple sources.All estimated solutions are in accordance with theoretical source parameters.We demonstrate the practicability of the Euler–DEXP method with the gravity field data of the Hastings Salt Dome.The results ultimately represent a better understanding of the geometry and depth of the salt dome.
基金Project(51075350)supported by the National Natural Science Foundation of China
文摘Based on electromagnetics and mechanics, electromechanical coupled dynamic equations for the drive were developed. Using method of perturbation, free vibrations of the mechanical system under electric disturbance were investigated. The forced responses of the mechanical system to mechanical excitation under electric disturbance were also presented. It is known that for the system with electric disturbance, as time grows, beat occurs. When electric disturbing frequency is near to the natural frequencies of the mechanical system or their integer multiple, resonance vibrations occur. The forced responses of the mechanical system to mechanical excitation under electric disturbance are compound vibrations decided by mechanical excitation, electric disturbance and parameters of the system. The coupled resonance vibration caused by electric disturbance and mechanical excitation was discussed as well. The conditions under which above coupled resonance occurs were presented. The results show that when the difference of the excitation frequency and the perturbation frequency is equal to some order of natural frequency, coupled resonance vibrations occur.
文摘Academic research into service industries has explored the characteristics of interpersonal interactions between employees and customers, but there are few studies addressing the issues of consumer interaction with technology and its influence on the objectives and results of the operations subsystem. This study examines the elements of the service encounter, and the changes automation originates in them and their relationships. The paper also examines changes in the elements and results of the operations subsystem, as a result of automation. We propose that the customer's relationship with employees and/or technology and automated systems for the service impact the objectives and results of the operations subsystem, all of which could have an effect on the company's competitive position. The empirical study is focused on four industries, namely, toll motorways, car parks, carwash and video/DVD rental companies, in an attempt to identify objectives that lead companies to implement automated processes affecting the customer's relationship with the company. The hypotheses generated are contrasted with a structural equation modelling. The results confirm that the customer's relationship with employees and automated systems for the service impacts the objectives and results of the operations subsystem. Also, the results show how automation can enable firms simultaneously to achieve acceptable levels of flexibility and productivity, two dimensions that have traditionally been considered opposites.
基金Natural Science Foundation of Shaanxi Province(No.2011J2009)。
文摘In order to solve the problem of vibration bounce caused by the contact between moving and stationary contacts in the process of switching on,two-degree-of-freedom motion differential equation of the contact system is established.Genetic algorithm is used to optimize the pull in process of AC contactor.The whole process of contact bounce was observed and analyzed by high-speed photography experiment.The theory and experimental results were very similar.The iron core has collided before the contact is separated,which further aggravates the contact bounce.When the iron core bounces collided again,the bounce of the contact was not affected.During the operation of the contactor,the movement of the moving iron core will cause slight vibration of the system.The contact bounce time and the maximum amplitude are reduced.The research results provide a theoretical basis for further control and reduction of contact bounce.
基金supported by NSFC-90718041NKBRPC-2005C B321902+1 种基金China Scholarship Council in Chinasupported by the National Science Foundation award CCF-0729097
文摘Checking whether a given formula is an invariant at a given program location(especially,inside a loop) can be quite nontrivial even for simple loop programs,given that it is in general an undecidable property.This is especially the case if the given formula is not an inductive loop invariant,as most automated techniques can only check or generate inductive loop invariants.In this paper,conditions are identified on simple loops and formulas when this check can be performed automatically.A general theorem is proved which gives a necessary and sufficient condition for a formula to be an invariant under certain restrictions on a loop.As a byproduct of this analysis,a new kind of loop invariant inside the loop body,called inside-loop invariant,is proposed.Such an invariant is more general than an inductive loop invariant typically used in the Floyd-Hoare axiomatic approach to program verification.The use of such invariants for program debugging is explored;it is shown that such invariants can be more useful than traditional inductive loop invariants especially when one is interested in checking extreme/side conditions such as underflow,accessing array/collection data structures outside the range,divide by zero,etc.
基金supported by the National Twelfth Five-year Technology Support Projects of China (Grant Nos. 2009BAJ28B04, 2011BAK07B01,2011BAJ08B03, and 2011BAJ08B05)the National Natural Science Foundation of China (Grant No. 51208017)+1 种基金Beijing Postdoctoral Research Foundation (Grant No. 2012ZZ-17)China Postdoctoral Science Foundation Funded Project (Grant No. 2011M500199)
文摘This paper describes a non-linear information dynamics model for integrated risk assessment of complex disaster system from an evolution perspective. According to the occurrence and evolution of natural disaster system with complicated and nonlinear characteristics, a non-linear information dynamics mode is introduced based on the maximum flux principle during modeling process to study the integrated risk assessment of complex disaster system. Based on the non-equilibrium statistical mechanics method, a stochastic evolution equation of this system is established. The integrated risk assessment of complex disaster system can be achieved by giving reasonable weights of each evaluation index to stabilize the system. The new model reveals the formation pattern of risk grade and the dynamics law of evolution. Meanwhile, a method is developed to solve the dynamics evolution equations of complex system through the self-organization feature map algorithm. The proposed method has been used in complex disaster integrated risk assessment for 31 provinces, cities and autonomous regions in China mainland. The results have indicated that the model is objective and effective.