With the rapid expansion of e-commerce,its security and risk management problems become increasingly prominent.In the current business environment,the ability to understand and apply e-commerce security and risk manag...With the rapid expansion of e-commerce,its security and risk management problems become increasingly prominent.In the current business environment,the ability to understand and apply e-commerce security and risk management has become an important criterion to measure a good person.Therefore,the importance of e-commerce security and risk management courses in college education is self-evident.This course can not only help students master the basic knowledge of e-commerce,but also enable them to understand how to deal with various risks in practical work and ensure the safe operation of e-commerce.At the same time,through the study of e-commerce security and risk management,students can better understand the operation mode and law of e-commerce,and lay a solid foundation for their future career.In general,e-commerce security and risk management occupy an important position in the curriculum of colleges and universities,and play a crucial role in cultivating e-commerce professionals with practical operation ability and innovative thinking.展开更多
In the 21st century,which is known as the age of information,the integration of electronic technology and e-commerce has become an irreversible trend in the field of business.This trend not only promotes the innovativ...In the 21st century,which is known as the age of information,the integration of electronic technology and e-commerce has become an irreversible trend in the field of business.This trend not only promotes the innovative development of e-commerce,but also brings unprecedented opportunities and challenges for enterprises.With the continuous development and popularization of Internet technology,more and more people choose to carry out shopping,payment and other consumption activities through e-commerce platforms,which also provides merchants with a broader market space and more sales channels.At the same time,e-commerce also brings more convenience and choice to consumers,making it easier for consumers to obtain the goods and services they need.However,the development of e-commerce has also brought some new challenges,such as how to ensure the quality of goods,how to protect consumer privacy and so on.Therefore,enterprises and government departments need to strengthen the supervision and management of e-commerce to ensure its healthy and orderly development.In general,the integration of electronic technology and e-commerce has become an important trend in today’s business field,which brings both opportunities and challenges to enterprises.展开更多
Limit equilibrium method (LEM) and strength reduction method (SRM) are the most widely used methods for slope stability analysis. However, it can be noted that they both have some limitations in practical applicat...Limit equilibrium method (LEM) and strength reduction method (SRM) are the most widely used methods for slope stability analysis. However, it can be noted that they both have some limitations in practical application. In the LEM, the constitutive model cannot be considered and many assumptions are needed between slices of soil/rock. The SRM requires iterative calculations and does not give the slip surface directly. A method for slope stability analysis based on the graph theory is recently developed to directly calculate the minimum safety factor and potential critical slip surface according to the stress results of numerical simulation. The method is based on current stress state and can overcome the disadvantages mentioned above in the two traditional methods. The influences of edge generation and mesh geometry on the position of slip surface and the safety factor of slope are studied, in which a new method for edge generation is proposed, and reasonable mesh size is suggested. The results of benchmark examples and a rock slope show good accuracy and efficiency of the presented method.展开更多
In the framework of finite element meshes,a novel continuous/discontinuous deformation analysis(CDDA)method is proposed in this paper for modeling of crack problems.In the present CDDA,simple polynomial interpolations...In the framework of finite element meshes,a novel continuous/discontinuous deformation analysis(CDDA)method is proposed in this paper for modeling of crack problems.In the present CDDA,simple polynomial interpolations are defined at the deformable block elements,and a link element is employed to connect the adjacent block elements.The CDDA is particularly suitable for modeling the fracture propagation because the switch from continuous deformation analysis to discontinuous deformation analysis is natural and convenient without additional procedures.The SIFs(stress intensity factors)for various types of cracks,such as kinked cracks or curved cracks,can be easily computed in the CDDA by using the virtual crack extension technique(VCET).Both the formulation and implementation of the VCET in CDDA are simple and straightforward.Numerical examples indicate that the present CDDA can obtain high accuracy in SIF results with simple polynomial interpolations and insensitive to mesh sizes,and can automatically simulate the crack propagation without degrading accuracy.展开更多
The evaluation of the seismic stability of high rock slopes is of vital importance to ensure the safe operation of the hydropower stations.In this paper,an equivalent pseudo-static force analysis based on the finite e...The evaluation of the seismic stability of high rock slopes is of vital importance to ensure the safe operation of the hydropower stations.In this paper,an equivalent pseudo-static force analysis based on the finite element method is developed to evaluate the seismic stability of reinforced rock slopes where the prestressed cables are modeled by the bar elements applied with nodal forces and bounded only at the anchored parts.The method is applied to analyze a high rock slope in south-west China and the optimization of cables.The stabilization effects of prestressed cables on the seismic stability of the slope are studied,the simulations of the concrete heading are discussed and the potential failure modes of the shear concrete plug are compared.Based on this,the optimization of cables is studied including the anchor spacing and inclined angles.展开更多
文摘With the rapid expansion of e-commerce,its security and risk management problems become increasingly prominent.In the current business environment,the ability to understand and apply e-commerce security and risk management has become an important criterion to measure a good person.Therefore,the importance of e-commerce security and risk management courses in college education is self-evident.This course can not only help students master the basic knowledge of e-commerce,but also enable them to understand how to deal with various risks in practical work and ensure the safe operation of e-commerce.At the same time,through the study of e-commerce security and risk management,students can better understand the operation mode and law of e-commerce,and lay a solid foundation for their future career.In general,e-commerce security and risk management occupy an important position in the curriculum of colleges and universities,and play a crucial role in cultivating e-commerce professionals with practical operation ability and innovative thinking.
文摘In the 21st century,which is known as the age of information,the integration of electronic technology and e-commerce has become an irreversible trend in the field of business.This trend not only promotes the innovative development of e-commerce,but also brings unprecedented opportunities and challenges for enterprises.With the continuous development and popularization of Internet technology,more and more people choose to carry out shopping,payment and other consumption activities through e-commerce platforms,which also provides merchants with a broader market space and more sales channels.At the same time,e-commerce also brings more convenience and choice to consumers,making it easier for consumers to obtain the goods and services they need.However,the development of e-commerce has also brought some new challenges,such as how to ensure the quality of goods,how to protect consumer privacy and so on.Therefore,enterprises and government departments need to strengthen the supervision and management of e-commerce to ensure its healthy and orderly development.In general,the integration of electronic technology and e-commerce has become an important trend in today’s business field,which brings both opportunities and challenges to enterprises.
基金support of the National Natural Science Foundation of China (Grant No. 41130751)China Scholarship Council, Research Program for Western China Communication (Grant No. 2011ZB04)China Central University Funding
文摘Limit equilibrium method (LEM) and strength reduction method (SRM) are the most widely used methods for slope stability analysis. However, it can be noted that they both have some limitations in practical application. In the LEM, the constitutive model cannot be considered and many assumptions are needed between slices of soil/rock. The SRM requires iterative calculations and does not give the slip surface directly. A method for slope stability analysis based on the graph theory is recently developed to directly calculate the minimum safety factor and potential critical slip surface according to the stress results of numerical simulation. The method is based on current stress state and can overcome the disadvantages mentioned above in the two traditional methods. The influences of edge generation and mesh geometry on the position of slip surface and the safety factor of slope are studied, in which a new method for edge generation is proposed, and reasonable mesh size is suggested. The results of benchmark examples and a rock slope show good accuracy and efficiency of the presented method.
基金The authors gratefully acknowledge the support of Nature Science Foundation of China(Grant No.41130751)National Basic Research Program of China(Grant No.2011CB013800)New Century Excellent Talents Project in China(NCET-12-0415).
文摘In the framework of finite element meshes,a novel continuous/discontinuous deformation analysis(CDDA)method is proposed in this paper for modeling of crack problems.In the present CDDA,simple polynomial interpolations are defined at the deformable block elements,and a link element is employed to connect the adjacent block elements.The CDDA is particularly suitable for modeling the fracture propagation because the switch from continuous deformation analysis to discontinuous deformation analysis is natural and convenient without additional procedures.The SIFs(stress intensity factors)for various types of cracks,such as kinked cracks or curved cracks,can be easily computed in the CDDA by using the virtual crack extension technique(VCET).Both the formulation and implementation of the VCET in CDDA are simple and straightforward.Numerical examples indicate that the present CDDA can obtain high accuracy in SIF results with simple polynomial interpolations and insensitive to mesh sizes,and can automatically simulate the crack propagation without degrading accuracy.
基金The authors gratefully acknowledge the supports from National Natural Science Foundation of China(Grant No.51109162)China National Twelfth Five-Year Science and Technology Supporting Programme(2011BAB08B01)Research Programme for Western China Communication(2011ZB04)and the Fundamental Research Funds for the Central Universities.
文摘The evaluation of the seismic stability of high rock slopes is of vital importance to ensure the safe operation of the hydropower stations.In this paper,an equivalent pseudo-static force analysis based on the finite element method is developed to evaluate the seismic stability of reinforced rock slopes where the prestressed cables are modeled by the bar elements applied with nodal forces and bounded only at the anchored parts.The method is applied to analyze a high rock slope in south-west China and the optimization of cables.The stabilization effects of prestressed cables on the seismic stability of the slope are studied,the simulations of the concrete heading are discussed and the potential failure modes of the shear concrete plug are compared.Based on this,the optimization of cables is studied including the anchor spacing and inclined angles.