In recent years, the bridge safety monitoring has been paid more attention in engineering field. How- ever, the financial and material resources as well as human resources were costly for the traditional monitoring me...In recent years, the bridge safety monitoring has been paid more attention in engineering field. How- ever, the financial and material resources as well as human resources were costly for the traditional monitoring means. Besides, the traditional means of monitoring were low in accuracy. From an engineering example, based on neural network method and historical data of the bridge monitoring to construct the BP neural network model with dual hidden layer strueture, the bridge temperature field and its effect on the behavior of bridge deflection are forecasted. The fact indicates that the predicted biggest error is 3.06% of the bridge temperature field and the bridge deflection behavior under temperature field affected is 2. 17% by the method of the BP neural net-work, which fully meet the precision requirements of the construction with practical value.展开更多
With the rapid development of the economy in China, the seismic network has been changing rapidly, in that the capability of instruments, technological systems and network density are approaching those of developed co...With the rapid development of the economy in China, the seismic network has been changing rapidly, in that the capability of instruments, technological systems and network density are approaching those of developed countries and a large quantity of observation data has been accumulated. How to apply these resources to economic construction and public safety has become an important issue worth studying. In order to improve earthquake prediction and earthquake emergency response, it is suggested in this paper that extracting valuable precursor information, improving earthquake rapid reporting ability and extending rapid intensity reporting function are key issues. Integrating network resources, building unified standards and a multifunction seismic monitoring network are preconditions of establishing a public safety service platform and earthquake observation resources will contribute significantly to the fields of engineering, ocean, meteorology, and environmental protection. Thus, the future directions of the development of the seismic network are exploring monitoring resources, enhancing independent innovation, constructing a technological platform and enlarging the service field.展开更多
Recently,virtualization technologies have been widely used in industry.In order to monitor the security of target systems in virtualization environments,conventional methods usually put the security monitoring mechani...Recently,virtualization technologies have been widely used in industry.In order to monitor the security of target systems in virtualization environments,conventional methods usually put the security monitoring mechanism into the normal functionality of the target systems.However,these methods are either prone to be tempered by attackers or introduce considerable performance overhead for target systems.To address these problems,in this paper,we present a concurrent security monitoring method which decouples traditional serial mechanisms,including security event collector and analyzer,into two concurrent components.On one hand,we utilize the SIM framework to deploy the event collector into the target virtual machine.On the other hand,we combine the virtualization technology and multi-core technology to put the event analyzer into a trusted execution environment.To address the synchronization problem between these two concurrent components,we make use of Lamport's ring buffer algorithm.Based on the Xen hypervisor,we have implemented a prototype system named COMO.The experimental results show that COMO can monitor the security of the target virtual machine concurrently within a little performance overhead.展开更多
Analyzed the monitor results under current systems concerning game and then pointed out that a way-out to improve chinese coal mine production safety control is to implement system innovation and punish the monitor's...Analyzed the monitor results under current systems concerning game and then pointed out that a way-out to improve chinese coal mine production safety control is to implement system innovation and punish the monitor's lazy behaviors strictly.展开更多
Based on the principal component analysis, principal components that have major influence on data variance are determined by the energy percentage method according to the correlation between monitoring effects. Then p...Based on the principal component analysis, principal components that have major influence on data variance are determined by the energy percentage method according to the correlation between monitoring effects. Then principal components are extracted through reconstructing multi effects. Moreover, combining with the optimal estimation theory, the method of singular value diagnosis in dam safety monitoring effect values is proposed. After dam monitoring information matrix is obtained, single effect state estimation matrix and multi effect fusion estimation matrix are constructed to make diagnosis on singular values to reduce false alarm rate. And the diagnosis index is calculated by PCA. These methods have already been applied to an actual project and the result shows the ability of the monitoring effect reflecting dam evolution behavior is improved as dam safety monitoring effect fusion estimation can take accurate identification on singular values and achieve data reduction, filter out noise and lower false alarm rate effectively.展开更多
An extended finite element method incorporated with the cohesive crack model(CCM-based XFEM) is developed in consideration of crack tip enrichment.It could improve the accuracy and is introduced into dam safety monito...An extended finite element method incorporated with the cohesive crack model(CCM-based XFEM) is developed in consideration of crack tip enrichment.It could improve the accuracy and is introduced into dam safety monitoring for the first time.Firstly,the proposed method is verified for a benchmark concrete beam by comparing the results with those of numerical investigations obtained by other researchers.Furthermore,it is adopted as an alternative method for building the deformation hybrid models of non-stable cracks in an arc dam,for the reason that classical FEMs are cumbersome in modeling the cohesive crack growth due to the need of remeshing the moving discontinuities.Case study proves that the fitted results of the mentioned deformation hybrid model,better than the classical statistical model,are well consistent with the measured data and reliable to forecast the development tendency of crack deformation.Therefore,the present CCM-based XFEM could provide a practical way to simulate and monitor the cracking process in concrete arch dam.展开更多
Ultraviolet(UV)visualization has extensive applications in military and civil fields such as security monitoring,space communication,and wearable equipment for health monitoring in the internet of things(IoT).Due to t...Ultraviolet(UV)visualization has extensive applications in military and civil fields such as security monitoring,space communication,and wearable equipment for health monitoring in the internet of things(IoT).Due to their remarkable optoelectronic features,perovskite materials are regarded as promising candidates for UV light detecting and imaging.Herein,we report for the first time the excitationdependent perovskite/polymer films with dynamically tunable fluorescence ranging from green to magenta by changing the UV excitation from 260 to 380 nm.And they still render dynamic multicolor UV light imaging with different polymer matrixes,halogen ratios,and cations of perovskite materials.The mechanism of its fluorescence change is related to the chloride vacancies in perovskite materials.A patterned multi-color ultraviolet visualization pad is also demonstrated for visible conversion of the UV region.This technique may provide a universal strategy for information securities,UV visualizations,and dynamic multi-color displays in the IoT.展开更多
文摘In recent years, the bridge safety monitoring has been paid more attention in engineering field. How- ever, the financial and material resources as well as human resources were costly for the traditional monitoring means. Besides, the traditional means of monitoring were low in accuracy. From an engineering example, based on neural network method and historical data of the bridge monitoring to construct the BP neural network model with dual hidden layer strueture, the bridge temperature field and its effect on the behavior of bridge deflection are forecasted. The fact indicates that the predicted biggest error is 3.06% of the bridge temperature field and the bridge deflection behavior under temperature field affected is 2. 17% by the method of the BP neural net-work, which fully meet the precision requirements of the construction with practical value.
基金This project was sponsored by the National Natural Science Foundation of China (50378086)
文摘With the rapid development of the economy in China, the seismic network has been changing rapidly, in that the capability of instruments, technological systems and network density are approaching those of developed countries and a large quantity of observation data has been accumulated. How to apply these resources to economic construction and public safety has become an important issue worth studying. In order to improve earthquake prediction and earthquake emergency response, it is suggested in this paper that extracting valuable precursor information, improving earthquake rapid reporting ability and extending rapid intensity reporting function are key issues. Integrating network resources, building unified standards and a multifunction seismic monitoring network are preconditions of establishing a public safety service platform and earthquake observation resources will contribute significantly to the fields of engineering, ocean, meteorology, and environmental protection. Thus, the future directions of the development of the seismic network are exploring monitoring resources, enhancing independent innovation, constructing a technological platform and enlarging the service field.
基金supported in part by National Natural Science Foundation of China(NSFC)under Grant No.61100228 and 61202479the National High-tech R&D Program of China under Grant No.2012AA013101+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No.XDA06030601 and XDA06010701Open Found of Key Laboratory of IOT Application Technology of Universities in Yunnan Province Grant No.2015IOT03
文摘Recently,virtualization technologies have been widely used in industry.In order to monitor the security of target systems in virtualization environments,conventional methods usually put the security monitoring mechanism into the normal functionality of the target systems.However,these methods are either prone to be tempered by attackers or introduce considerable performance overhead for target systems.To address these problems,in this paper,we present a concurrent security monitoring method which decouples traditional serial mechanisms,including security event collector and analyzer,into two concurrent components.On one hand,we utilize the SIM framework to deploy the event collector into the target virtual machine.On the other hand,we combine the virtualization technology and multi-core technology to put the event analyzer into a trusted execution environment.To address the synchronization problem between these two concurrent components,we make use of Lamport's ring buffer algorithm.Based on the Xen hypervisor,we have implemented a prototype system named COMO.The experimental results show that COMO can monitor the security of the target virtual machine concurrently within a little performance overhead.
文摘Analyzed the monitor results under current systems concerning game and then pointed out that a way-out to improve chinese coal mine production safety control is to implement system innovation and punish the monitor's lazy behaviors strictly.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51079046, 50909041, 50809025, and 50879024)the National Science and Technology Support Plan (Grant Nos. 2008BAB29B03and 2008BAB29B06)+6 种基金the Special Fund of State Key Laboratory of China (Grant Nos. 2009586012, 2009586912, and 2010585212)the Fundamental Research Funds for the Central Universities (Grant Nos. 2009B08514, 2010B20414, 2010B01414, and 2010B14114)the China Hydropower Engineering Consulting Group Co. Science and Technology Support Pro-ject (Grant No. CHC-KJ-2007-02)Jiangsu Province "333 High-Level Personnel Training Project" (Grant No. 2017-B08037)Graduate Innovation Program of Universities in Jiangsu Province (Grant No. CX09B_ 163Z)Dominant Discipline Construction Program Funded Projects of University in Jiangsu ProvineScience Foundation for the Excellent Youth Scholars of Ministry of Education of China (Grant No. 20070294023)
文摘Based on the principal component analysis, principal components that have major influence on data variance are determined by the energy percentage method according to the correlation between monitoring effects. Then principal components are extracted through reconstructing multi effects. Moreover, combining with the optimal estimation theory, the method of singular value diagnosis in dam safety monitoring effect values is proposed. After dam monitoring information matrix is obtained, single effect state estimation matrix and multi effect fusion estimation matrix are constructed to make diagnosis on singular values to reduce false alarm rate. And the diagnosis index is calculated by PCA. These methods have already been applied to an actual project and the result shows the ability of the monitoring effect reflecting dam evolution behavior is improved as dam safety monitoring effect fusion estimation can take accurate identification on singular values and achieve data reduction, filter out noise and lower false alarm rate effectively.
基金supported by the National Natural Science Foundation of China (Grant Nos. 50879024,50909041)Special Fund of State Key Laboratory of China (Grant Nos. 2009586012,2010585212) the Fun-damental Research Funds for the Central Universities (Grant Nos. 2009B08514,2010B20414)
文摘An extended finite element method incorporated with the cohesive crack model(CCM-based XFEM) is developed in consideration of crack tip enrichment.It could improve the accuracy and is introduced into dam safety monitoring for the first time.Firstly,the proposed method is verified for a benchmark concrete beam by comparing the results with those of numerical investigations obtained by other researchers.Furthermore,it is adopted as an alternative method for building the deformation hybrid models of non-stable cracks in an arc dam,for the reason that classical FEMs are cumbersome in modeling the cohesive crack growth due to the need of remeshing the moving discontinuities.Case study proves that the fitted results of the mentioned deformation hybrid model,better than the classical statistical model,are well consistent with the measured data and reliable to forecast the development tendency of crack deformation.Therefore,the present CCM-based XFEM could provide a practical way to simulate and monitor the cracking process in concrete arch dam.
基金supported by the National Natural Science Foundation of China(52125205,11974317,11674290,U20A20166,U1704138,52192614,61805015,and 61804011)the National Key R&D Program of China(2021YFB3200302 and 2021YFB3200304)+5 种基金Natural Science Foundation of Beijing Municipality(Z180011 and 2222088)Shenzhen Science and Technology Program(KQTD20170810105439418)the Fundamental Research Funds for the Central UniversitiesHenan Science Fund for Distinguished Young Scholars(212300410020)Key Project of Henan Higher Education(21A140001)the Zhengzhou University Physics Discipline Improvement Program。
文摘Ultraviolet(UV)visualization has extensive applications in military and civil fields such as security monitoring,space communication,and wearable equipment for health monitoring in the internet of things(IoT).Due to their remarkable optoelectronic features,perovskite materials are regarded as promising candidates for UV light detecting and imaging.Herein,we report for the first time the excitationdependent perovskite/polymer films with dynamically tunable fluorescence ranging from green to magenta by changing the UV excitation from 260 to 380 nm.And they still render dynamic multicolor UV light imaging with different polymer matrixes,halogen ratios,and cations of perovskite materials.The mechanism of its fluorescence change is related to the chloride vacancies in perovskite materials.A patterned multi-color ultraviolet visualization pad is also demonstrated for visible conversion of the UV region.This technique may provide a universal strategy for information securities,UV visualizations,and dynamic multi-color displays in the IoT.