A near-equiatomic NiTi shape memory alloy was fabricated by rapid solidification process through vacuum arc melting followed by vacuum suction casting in water-cooled thick copper mold. The rapidly solidified （or suc...A near-equiatomic NiTi shape memory alloy was fabricated by rapid solidification process through vacuum arc melting followed by vacuum suction casting in water-cooled thick copper mold. The rapidly solidified （or suction cast） NiTi alloy shows much finer grains and homogenous microstructure, in particular a uniform distribution of various fine precipitates, compared to the conventional cast one. The resultant alloy also exhibits the homogenous Ni distribution in the matrix of the alloy, allowing the martensitic transformation to take place throughout the NiTi alloy matrix simultaneously and resulting in sharper transformation peaks compared to the conventional cast alloy. Moreover, the suction cast NiTJ alloy shows a significant improvement over the conventional cast one, in terms of possessing higher deformation recovery rates and displaying the increased compressive strength and damping capacity by 4% and 20%, respectively.展开更多
In an ever-changing environment,Software as a Service(SaaS)can rarely protect users'privacy.Being able to manage and control the privacy is therefore an important goal for SaaS.Once the participant of composite se...In an ever-changing environment,Software as a Service(SaaS)can rarely protect users'privacy.Being able to manage and control the privacy is therefore an important goal for SaaS.Once the participant of composite service is substituted,it is unclear whether the composite service satisfy user privacy requirement or not.In this paper,we propose a privacy policies automatic update method to enhance user privacy when a service participant change in the composite service.Firstly,we model the privacy policies and service variation rules.Secondly,according to the service variation rules,the privacy policies are automatically generated through the negotiation between user and service composer.Thirdly,we prove the feasibility and applicability of our method with the experiments.When the service quantity is 50,ratio that the services variations are successfully checked by monitor is 81%.Moreover,ratio that the privacy policies are correctly updated is 93.6%.展开更多
Cyber-physical space is a spatial environment that integrates the cyber world and the physical world,aiming to provide an intelligent environment for users to conduct their day-to-day activities.The interplay between ...Cyber-physical space is a spatial environment that integrates the cyber world and the physical world,aiming to provide an intelligent environment for users to conduct their day-to-day activities.The interplay between the cyber space and physical space proposes specific security requirements that are not captured by traditional access control frameworks.On one hand,the security of the physical space and the cyber space should be both concerned in the cyber-physical space.On the other hand,the bad results caused by failure in providing secure policy enforcement may directly affect the controlled physical world.In this paper,we propose an effective access control framework for the cyber-physical space.Firstly,a topology-aware access control(TAAC)model is proposed.It can express the cyber access control,the physical access control,and the interaction access control simultaneously.Secondly,a risk assessment approach is proposed for the policy enforcement phase.It is used to evaluate the user behavior and ensures that the suspicious behaviors executed by authorized users can be handled correctly.Thirdly,we propose a role activation algorithm to ensure that the objects are accessed only by legal and honest users.Finally,we evaluate our approach by using an illustrative example and the performance analysis.The results demonstrate the feasibility of our approach.展开更多
基金supported by the National Natural Science Foundation of China under grant Nos. 50871039 and 51205135Guangdong Provincial Natural Science Foundation under grant Nos. 10151064101000017 and S2011040001436the Fundamental Research Funds for Central Universities (SCUT2011ZM0001)
文摘A near-equiatomic NiTi shape memory alloy was fabricated by rapid solidification process through vacuum arc melting followed by vacuum suction casting in water-cooled thick copper mold. The rapidly solidified （or suction cast） NiTi alloy shows much finer grains and homogenous microstructure, in particular a uniform distribution of various fine precipitates, compared to the conventional cast one. The resultant alloy also exhibits the homogenous Ni distribution in the matrix of the alloy, allowing the martensitic transformation to take place throughout the NiTi alloy matrix simultaneously and resulting in sharper transformation peaks compared to the conventional cast alloy. Moreover, the suction cast NiTJ alloy shows a significant improvement over the conventional cast one, in terms of possessing higher deformation recovery rates and displaying the increased compressive strength and damping capacity by 4% and 20%, respectively.
基金supported by the Nature Science Foundation of Jiangsu for Distinguished Young Scientist(BK20170039)Guangxi Natural Science Foundation(2018GXNSFAA050046)Fund for Talents for Scientific Research at Jinling Institute of Technology,and Science Foundations of Nanjing Institute of Technology(CKJB201906).
文摘In an ever-changing environment,Software as a Service(SaaS)can rarely protect users'privacy.Being able to manage and control the privacy is therefore an important goal for SaaS.Once the participant of composite service is substituted,it is unclear whether the composite service satisfy user privacy requirement or not.In this paper,we propose a privacy policies automatic update method to enhance user privacy when a service participant change in the composite service.Firstly,we model the privacy policies and service variation rules.Secondly,according to the service variation rules,the privacy policies are automatically generated through the negotiation between user and service composer.Thirdly,we prove the feasibility and applicability of our method with the experiments.When the service quantity is 50,ratio that the services variations are successfully checked by monitor is 81%.Moreover,ratio that the privacy policies are correctly updated is 93.6%.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.61772270,61602262 and 61602237)Jiangsu Natural Science Foundation of China(BK20170809)National High Technology Research and Development Program of China(2015AA015303).
文摘Cyber-physical space is a spatial environment that integrates the cyber world and the physical world,aiming to provide an intelligent environment for users to conduct their day-to-day activities.The interplay between the cyber space and physical space proposes specific security requirements that are not captured by traditional access control frameworks.On one hand,the security of the physical space and the cyber space should be both concerned in the cyber-physical space.On the other hand,the bad results caused by failure in providing secure policy enforcement may directly affect the controlled physical world.In this paper,we propose an effective access control framework for the cyber-physical space.Firstly,a topology-aware access control(TAAC)model is proposed.It can express the cyber access control,the physical access control,and the interaction access control simultaneously.Secondly,a risk assessment approach is proposed for the policy enforcement phase.It is used to evaluate the user behavior and ensures that the suspicious behaviors executed by authorized users can be handled correctly.Thirdly,we propose a role activation algorithm to ensure that the objects are accessed only by legal and honest users.Finally,we evaluate our approach by using an illustrative example and the performance analysis.The results demonstrate the feasibility of our approach.
