Conditional access system (CAS) is a key technical component in digital TV broadcasting through which TV op-erators manage the appropriate rights of different subscribers in order to protect their commercial benefits....Conditional access system (CAS) is a key technical component in digital TV broadcasting through which TV op-erators manage the appropriate rights of different subscribers in order to protect their commercial benefits. The normal digital TV receiver can only receive and decode the pay TV programs scrambled by one specific CAS. In this paper, the authors proposed a smartcard conditional access interface (SCAI) scheme in order to make the digital TV receiver be a common receiving platform independent of any specific CAS employed at the broadcasting head-end. As a result, it only needs to include a common condi-tional access software package (CCAP) without any requirement of hardware modification in the receiver. Comparison between the two mentioned DVB-CI-based schemes showed that the cost of such kind receiver is greatly reduced. The main design points of the proposed scheme and its reference implementation’s architecture are presented in this paper. This scheme is also one of the candidate national standards for Chinese digital TV broadcasting industry.展开更多
With the advancement in internet technologies, the number of servers has increased remarkably to provide more services to the end users. These services are provided over the public channels, which are insecure and sus...With the advancement in internet technologies, the number of servers has increased remarkably to provide more services to the end users. These services are provided over the public channels, which are insecure and susceptible to interception, modification, and deletion. To provide security, registered entities are authenticated and then a session key is established between them to communicate securely. The conventional schemes anow a user to access services only after their independent registration with each desired server in a multiserver system. Therefore, a user must possess multiple smartcards and memorize various identities and passwords for obtaining services from multiple servers. This has led to the adoption of multiserver authentication in which a user accesses services of multiple servers after registering himself at only one central authority. Recently, Kumar and Om discussed a scheme for multiserver environment by using smartcard. Since the user-memorized passwords are of low entropy, it is possible for an attacker to guess them. This paper uses biometric information of user to enhance the security of the scheme by Kumar and Ore. Moreover, we conducted rigorous security analyses （informal and formal） in this study to prove the security of the proposed scheme against all known attacks. We also simulated our scheme by using the automated tool, ProVerif, to prove its secrecy and authentication properties. A comparative study of the proposed scheme with the existing related schemes shows its effectiveness.展开更多
In order to explore the travel characteristics and space-time distribution of different groups of bikeshare users,an online analytical processing(OLAP)tool called data cube was used for treating and displaying multi-d...In order to explore the travel characteristics and space-time distribution of different groups of bikeshare users,an online analytical processing(OLAP)tool called data cube was used for treating and displaying multi-dimensional data.We extended and modified the traditionally threedimensional data cube into four dimensions,which are space,date,time,and user,each with a user-specified hierarchy,and took transaction numbers and travel time as two quantitative measures.The results suggest that there are two obvious transaction peaks during the morning and afternoon rush hours on weekdays,while the volume at weekends has an approximate even distribution.Bad weather condition significantly restricts the bikeshare usage.Besides,seamless smartcard users generally take a longer trip than exclusive smartcard users;and non-native users ride faster than native users.These findings not only support the applicability and efficiency of data cube in the field of visualizing massive smartcard data,but also raise equity concerns among bikeshare users with different demographic backgrounds.展开更多
In the literature, several dynamic ID-based remote user mutual authentication schemes are implemented using password, smartcard and Elliptic Curve Cryptography(ECC), however, none of them provides resilience against d...In the literature, several dynamic ID-based remote user mutual authentication schemes are implemented using password, smartcard and Elliptic Curve Cryptography(ECC), however, none of them provides resilience against different attacks. Therefore, there is a great need to design an efficient scheme for practical applications. In this paper, we proposed such a scheme in order to provide desired security attributes and computation efficiencies. Compared with other existing techniques, our scheme is more efficient and secured. In addition, our scheme is provably secure in the random oracle model under the hardness assumption of computational Diffie-Hellman problem.展开更多
Rail transit plays a crucial role in improving urban sustainability and livability.In many Chinese cities,the planning of rail transit routes and stations is focused on facilitating new developments rather than revita...Rail transit plays a crucial role in improving urban sustainability and livability.In many Chinese cities,the planning of rail transit routes and stations is focused on facilitating new developments rather than revitalizing existing built-up areas.This approach reflects the local governments’expectations of substantial growth to reshape the urban structure.However,existing research on transit-oriented development(TOD)rarely explores the spatial interactions between individual transit stations and investigates how they can be integrated to achieve synergistic effects and balanced development.This study proposes that rail transit systems impact urban structure through two“forces”:the provision of additional and reliable carrying capacity and the reduction of travel time between locations.Metro passenger flow is used as a proxy for these forces,and community detection techniques are employed to identify the actual and optimal spatial clusters in Wuhan,China.The results reveal that the planned sub-centers align reasonably well with the optimal spatial clusters in terms of spatial configuration.However,the actual spatial clusters tend to have longer internal travel times compared to the optimal clusters.Further exploration suggests the need for equalizing land use density within planned spatial clusters served by the metro system.Additionally,promoting concentrated,differentiated,and mixed functional arrangements in metro station areas with low passenger flows within the planned clusters could be beneficial.This paper presents a new framework for investigating urban spatial clusters influenced by a metro system.展开更多
基金Project (No. 200442) supported by the Electronics DevelopmentFoundation for the Key Industrialization Project of the Ministry of0Information Industry, China
文摘Conditional access system (CAS) is a key technical component in digital TV broadcasting through which TV op-erators manage the appropriate rights of different subscribers in order to protect their commercial benefits. The normal digital TV receiver can only receive and decode the pay TV programs scrambled by one specific CAS. In this paper, the authors proposed a smartcard conditional access interface (SCAI) scheme in order to make the digital TV receiver be a common receiving platform independent of any specific CAS employed at the broadcasting head-end. As a result, it only needs to include a common condi-tional access software package (CCAP) without any requirement of hardware modification in the receiver. Comparison between the two mentioned DVB-CI-based schemes showed that the cost of such kind receiver is greatly reduced. The main design points of the proposed scheme and its reference implementation’s architecture are presented in this paper. This scheme is also one of the candidate national standards for Chinese digital TV broadcasting industry.
文摘With the advancement in internet technologies, the number of servers has increased remarkably to provide more services to the end users. These services are provided over the public channels, which are insecure and susceptible to interception, modification, and deletion. To provide security, registered entities are authenticated and then a session key is established between them to communicate securely. The conventional schemes anow a user to access services only after their independent registration with each desired server in a multiserver system. Therefore, a user must possess multiple smartcards and memorize various identities and passwords for obtaining services from multiple servers. This has led to the adoption of multiserver authentication in which a user accesses services of multiple servers after registering himself at only one central authority. Recently, Kumar and Om discussed a scheme for multiserver environment by using smartcard. Since the user-memorized passwords are of low entropy, it is possible for an attacker to guess them. This paper uses biometric information of user to enhance the security of the scheme by Kumar and Ore. Moreover, we conducted rigorous security analyses （informal and formal） in this study to prove the security of the proposed scheme against all known attacks. We also simulated our scheme by using the automated tool, ProVerif, to prove its secrecy and authentication properties. A comparative study of the proposed scheme with the existing related schemes shows its effectiveness.
基金Supported by Projects of International Cooperation and Exchange of the National Natural Science Foundation of China(51561135003)Key Project of National Natural Science Foundation of China(51338003)Scientific Research Foundation of Graduated School of Southeast University(YBJJ1842)
文摘In order to explore the travel characteristics and space-time distribution of different groups of bikeshare users,an online analytical processing(OLAP)tool called data cube was used for treating and displaying multi-dimensional data.We extended and modified the traditionally threedimensional data cube into four dimensions,which are space,date,time,and user,each with a user-specified hierarchy,and took transaction numbers and travel time as two quantitative measures.The results suggest that there are two obvious transaction peaks during the morning and afternoon rush hours on weekdays,while the volume at weekends has an approximate even distribution.Bad weather condition significantly restricts the bikeshare usage.Besides,seamless smartcard users generally take a longer trip than exclusive smartcard users;and non-native users ride faster than native users.These findings not only support the applicability and efficiency of data cube in the field of visualizing massive smartcard data,but also raise equity concerns among bikeshare users with different demographic backgrounds.
文摘In the literature, several dynamic ID-based remote user mutual authentication schemes are implemented using password, smartcard and Elliptic Curve Cryptography(ECC), however, none of them provides resilience against different attacks. Therefore, there is a great need to design an efficient scheme for practical applications. In this paper, we proposed such a scheme in order to provide desired security attributes and computation efficiencies. Compared with other existing techniques, our scheme is more efficient and secured. In addition, our scheme is provably secure in the random oracle model under the hardness assumption of computational Diffie-Hellman problem.
文摘Rail transit plays a crucial role in improving urban sustainability and livability.In many Chinese cities,the planning of rail transit routes and stations is focused on facilitating new developments rather than revitalizing existing built-up areas.This approach reflects the local governments’expectations of substantial growth to reshape the urban structure.However,existing research on transit-oriented development(TOD)rarely explores the spatial interactions between individual transit stations and investigates how they can be integrated to achieve synergistic effects and balanced development.This study proposes that rail transit systems impact urban structure through two“forces”:the provision of additional and reliable carrying capacity and the reduction of travel time between locations.Metro passenger flow is used as a proxy for these forces,and community detection techniques are employed to identify the actual and optimal spatial clusters in Wuhan,China.The results reveal that the planned sub-centers align reasonably well with the optimal spatial clusters in terms of spatial configuration.However,the actual spatial clusters tend to have longer internal travel times compared to the optimal clusters.Further exploration suggests the need for equalizing land use density within planned spatial clusters served by the metro system.Additionally,promoting concentrated,differentiated,and mixed functional arrangements in metro station areas with low passenger flows within the planned clusters could be beneficial.This paper presents a new framework for investigating urban spatial clusters influenced by a metro system.
