Geodynamic drivers for the supercontinent cycle are generally attributed to either top-down(subduction-related)or bottom-up(mantle-related)processes.Compiled geochemical data and U-Pb ages and Hf isotopic signatures f...Geodynamic drivers for the supercontinent cycle are generally attributed to either top-down(subduction-related)or bottom-up(mantle-related)processes.Compiled geochemical data and U-Pb ages and Hf isotopic signatures for magmatic and detrital zircons from the Tarim Craton reveal a distinct change in subduction style during the Neoproterozoic.The subduction cycle is recorded in increasing and decreasing intensity of subduction-related magmatic rocks and time-equivalent sedimentary successions,and converse trends ofεHf(t)values and corresponding changes in crustal incubation time.These trends are consistent with a switch from advancing to retreating subduction.The switch likely occurred at ca.760 Ma when zirconεHf(t)values increase and crustal incubation times decrease following a transitional shift between 800 Ma and 760 Ma.A switch at this time is consistent with Rodinia breakup and may have resulted in the late Neoproterozoic Tarim rift basin.The long-lived(ca.500 Ma)subduction recorded in the Tarim Craton suggests the predominance of a top-down process for Rodinia breakup on this part of its margin.展开更多
The issue of privacy protection for mobile social networks is a frontier topic in the field of social network applications.The existing researches on user privacy protection in mobile social network mainly focus on pr...The issue of privacy protection for mobile social networks is a frontier topic in the field of social network applications.The existing researches on user privacy protection in mobile social network mainly focus on privacy preserving data publishing and access control.There is little research on the association of user privacy information,so it is not easy to design personalized privacy protection strategy,but also increase the complexity of user privacy settings.Therefore,this paper concentrates on the association of user privacy information taking big data analysis tools,so as to provide data support for personalized privacy protection strategy design.展开更多
With the rapid development of the new generation of information technology,the analysis of mobile social network big data is getting deeper and deeper.At the same time,the risk of privacy disclosure in social network ...With the rapid development of the new generation of information technology,the analysis of mobile social network big data is getting deeper and deeper.At the same time,the risk of privacy disclosure in social network is also very obvious.In this paper,we summarize the main access control model in mobile social network,analyze their contribution and point out their disadvantages.On this basis,a practical privacy policy is defined through authorization model supporting personalized privacy preferences.Experiments have been conducted on synthetic data sets.The result shows that the proposed privacy protecting model could improve the security of the mobile social network while keeping high execution efficiency.展开更多
In recent years,with the explosive development in Internet,data storage and data processing technologies,privacy preservation has been one of the greater concerns in data mining.A number of methods and techniques have...In recent years,with the explosive development in Internet,data storage and data processing technologies,privacy preservation has been one of the greater concerns in data mining.A number of methods and techniques have been developed for privacy preserving data mining.This paper provided a wide survey of different privacy preserving data mining algorithms and analyzed the representative techniques for privacy preservation.The existing problems and directions for future research are also discussed.展开更多
The Meso-Neoproterozoic strata are wildly distributed in North China Craton(NCC),of which Changchengian strata are most widely developed.Taking Changchengian strata in south margin of NCC as the study object,and combi...The Meso-Neoproterozoic strata are wildly distributed in North China Craton(NCC),of which Changchengian strata are most widely developed.Taking Changchengian strata in south margin of NCC as the study object,and combined with comprehensive analysis of isotopic chronology and petrology,it can be concluded that the Xiong'er rift is a plume rift which responds to breakup of Columbia supercontinent.Seismic data shows that Changchengian rifts are developed in the Qinshui Basin and the southern part of Ordos Basin covered by Phanerozoic strata,respectively are large-scale graben rifts and half-graben rifts.Aero magnetic data indicates that a NE-trending rift is developed in the west of the Xiong'er rift,and the Qinshui Basin rift is the extension of the north branch of the Xiong'er rift.The filling process of Changchengian rifts can be divided into four stages:the early rifting stage developing thick andesitic volcanic rocks,the late rifting stage developing large suite of coarse clastic sedimentary rocks,the depression stage developing fine clastic rocks,and the epeiric sea stage developing carbonate rocks.The dark argillaceous rocks are developed in Cuizhuang Formation and Chenjiajian Formation during the depression stage,and the black shale in Cuizhuang Formation is the effective source rocks.The bitume is filled in fractures of dolomite in Luoyukou Formation,as well as dissolution pores and large caves in Longjiayuan Formation.The argillaceous sandstone and muddy limestone of Lower Cambrian is the effective cap rocks,which can form an potential accumulation assemblage of Changchengian strata with underlying source rocks of Cuizhuang Formation and reservoirs of Luoyu Group,and this assemblage may be still effective at present.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.91955204)National Major Science and Technology Project of China(Grant No.2016ZX05004001)。
文摘Geodynamic drivers for the supercontinent cycle are generally attributed to either top-down(subduction-related)or bottom-up(mantle-related)processes.Compiled geochemical data and U-Pb ages and Hf isotopic signatures for magmatic and detrital zircons from the Tarim Craton reveal a distinct change in subduction style during the Neoproterozoic.The subduction cycle is recorded in increasing and decreasing intensity of subduction-related magmatic rocks and time-equivalent sedimentary successions,and converse trends ofεHf(t)values and corresponding changes in crustal incubation time.These trends are consistent with a switch from advancing to retreating subduction.The switch likely occurred at ca.760 Ma when zirconεHf(t)values increase and crustal incubation times decrease following a transitional shift between 800 Ma and 760 Ma.A switch at this time is consistent with Rodinia breakup and may have resulted in the late Neoproterozoic Tarim rift basin.The long-lived(ca.500 Ma)subduction recorded in the Tarim Craton suggests the predominance of a top-down process for Rodinia breakup on this part of its margin.
基金We thank the anonymous reviewers and editors for their very constructive comments.the National Social Science Foundation Project of China under Grant 16BTQ085.
文摘The issue of privacy protection for mobile social networks is a frontier topic in the field of social network applications.The existing researches on user privacy protection in mobile social network mainly focus on privacy preserving data publishing and access control.There is little research on the association of user privacy information,so it is not easy to design personalized privacy protection strategy,but also increase the complexity of user privacy settings.Therefore,this paper concentrates on the association of user privacy information taking big data analysis tools,so as to provide data support for personalized privacy protection strategy design.
基金We thank the anonymous reviewers and editors for their very constructive comments.This work was supported by the National Social Science Foundation Project of China under Grant 16BTQ085.
文摘With the rapid development of the new generation of information technology,the analysis of mobile social network big data is getting deeper and deeper.At the same time,the risk of privacy disclosure in social network is also very obvious.In this paper,we summarize the main access control model in mobile social network,analyze their contribution and point out their disadvantages.On this basis,a practical privacy policy is defined through authorization model supporting personalized privacy preferences.Experiments have been conducted on synthetic data sets.The result shows that the proposed privacy protecting model could improve the security of the mobile social network while keeping high execution efficiency.
基金This work was supported by the National Social Science Foundation Project of China under Grant 16BTQ085.
文摘In recent years,with the explosive development in Internet,data storage and data processing technologies,privacy preservation has been one of the greater concerns in data mining.A number of methods and techniques have been developed for privacy preserving data mining.This paper provided a wide survey of different privacy preserving data mining algorithms and analyzed the representative techniques for privacy preservation.The existing problems and directions for future research are also discussed.
基金The work was supported by the National Key Research and Development Program of China(No.2016YFC0601002)Frontier Basic Research Program of PetroChina Research Institute of Petroleum Exploration and Development(No.2015yj-09).
文摘The Meso-Neoproterozoic strata are wildly distributed in North China Craton(NCC),of which Changchengian strata are most widely developed.Taking Changchengian strata in south margin of NCC as the study object,and combined with comprehensive analysis of isotopic chronology and petrology,it can be concluded that the Xiong'er rift is a plume rift which responds to breakup of Columbia supercontinent.Seismic data shows that Changchengian rifts are developed in the Qinshui Basin and the southern part of Ordos Basin covered by Phanerozoic strata,respectively are large-scale graben rifts and half-graben rifts.Aero magnetic data indicates that a NE-trending rift is developed in the west of the Xiong'er rift,and the Qinshui Basin rift is the extension of the north branch of the Xiong'er rift.The filling process of Changchengian rifts can be divided into four stages:the early rifting stage developing thick andesitic volcanic rocks,the late rifting stage developing large suite of coarse clastic sedimentary rocks,the depression stage developing fine clastic rocks,and the epeiric sea stage developing carbonate rocks.The dark argillaceous rocks are developed in Cuizhuang Formation and Chenjiajian Formation during the depression stage,and the black shale in Cuizhuang Formation is the effective source rocks.The bitume is filled in fractures of dolomite in Luoyukou Formation,as well as dissolution pores and large caves in Longjiayuan Formation.The argillaceous sandstone and muddy limestone of Lower Cambrian is the effective cap rocks,which can form an potential accumulation assemblage of Changchengian strata with underlying source rocks of Cuizhuang Formation and reservoirs of Luoyu Group,and this assemblage may be still effective at present.