China is setting out on a new journey of building a modern socialist country in all respects after achieving moderate prosperity.Modern services are an important part of China’s economy,underpinning China’s developm...China is setting out on a new journey of building a modern socialist country in all respects after achieving moderate prosperity.Modern services are an important part of China’s economy,underpinning China’s development towards a great modern socialist country.Globalization,industrial development,urbanization,innovation and income growth will drive China’s service sector development.By 2035,the service sector will account for 60.98%and 59.12%of total value-added and employment,respectively,and labor productivity in the service sector will rise from 145,500 yuan/person in 2019 to 282,300 yuan/person.The Fifth Plenum of the 19th CPC Central Committee called for“basically achieving the vision of socialist modernization by 2035.”According to the CPC Central Committee’s overall arrangements for the 2035 vision,we must identify a clear strategic position and tasks for the development of modern services as a key element of the modern industrial system,enhance service sector competitiveness,and achieve service sector modernization.To achieve this strategic goal,we must promote digitalized,intelligent,platform-based,standardized,and quality-oriented service sector development.We must give play to the decisive role of the market and the macro-regulatory role of the government in spurring service innovation,industry integration and clustering,and service sector reform and openness.展开更多
Standard e-government information system(SEIS) including mobile-government applications are playing more and more important roles in the establishing of national e-government framework. It can be beneficial not only f...Standard e-government information system(SEIS) including mobile-government applications are playing more and more important roles in the establishing of national e-government framework. It can be beneficial not only for avoiding redundant e-government IS development but also for improving collaboration among government agencies. Two research questions were explored: what are the factors influencing the performance of SEIS? Will mandatory SEIS create a better performance than non-mandatory SEIS? Specifically, the use of five categories of IS aspects--information system quality, online service quality, offline service quality, diffusion modes and standard network size—is proposed to understand the performance of SEIS through applying both survey study and simulation study. The results show that information system quality and online service quality of SEIS have strong effects on users' expectation and users' satisfaction, which thereafter promotes the performance of SEIS. Government agencies' offline service quality shows a significant effect on users' satisfaction while not on users' expectation. Furthermore, the diffusion speed of SEIS in non-mandatory and mandatory modes and the standard network size also have great influence on the utility of SEIS.展开更多
In traditional framework,mandatory access control(MAC) system and malicious software are run in kernel mode. Malicious software can stop MAC systems to be started and make it do invalid. This problem cannot be solved ...In traditional framework,mandatory access control(MAC) system and malicious software are run in kernel mode. Malicious software can stop MAC systems to be started and make it do invalid. This problem cannot be solved under the traditional framework if the operating system(OS) is comprised since malwares are running in ring 0 level. In this paper,we propose a novel way to use hypervisors to protect kernel integrity and the access control system in commodity operating systems. We separate the access control system into three parts: policy management(PM),security server(SS) and policy enforcement(PE). Policy management and the security server reside in the security domain to protect them against malware and the isolation feather of the hypervisor can protect them from attacks. We add an access vector cache(AVC) between SS and PE in the guest OS,in order to speed up communication between the guest OS and the security domain. The policy enforcement module is retained in the guest OS for performance. The security of AVC and PE can be ensured by using a memory protection mechanism. The goal of protecting the OS kernel is to ensure the security of the execution path. We implementthe system by a modified Xen hypervisor. The result shows that we can secure the security of the access control system in the guest OS with no overhead compared with modules in the latter. Our system offers a centralized security policy for virtual domains in virtual machine environments.Keywords: hypervisor; virtualization; memo-展开更多
This paper suggests that a new approach should be taken for the development of China's service sector. Priorities for this include: appropriate objectives for service sector development, enhanced functionality, inte...This paper suggests that a new approach should be taken for the development of China's service sector. Priorities for this include: appropriate objectives for service sector development, enhanced functionality, integrated development between manufacturing and services, improved regional layout of the service sector, and the emergence of reputable brands and leading enterprises. Well-designed and effective industrial policies, as well as calls for major breakthroughs in institutional mechanisms, must support the development of the service sector. Additionally, excessive burdens and difficult financing channels need to be addressed. More attention should be paid to the construction of the credit system, service standardization, and service statistical accounting as element tasks.展开更多
Landscape-scale pattern could affect ecosystem service such as biocontrol of agricultural pests. Additionally, pest outbreak has been shown to be interwoven with land-use intensity. In the present research, we collect...Landscape-scale pattern could affect ecosystem service such as biocontrol of agricultural pests. Additionally, pest outbreak has been shown to be interwoven with land-use intensity. In the present research, we collected and analysed the 60-year data of cereal aphids and wheat area during 1951–2010 in China. Regression model was applied to analyse the relationship between pest damage and cropland expansion. Results showed that the percentage of cereal aphid outbreak area in wheat area increased rapidly during 1951–2010. It was 9 % during 1951–1960, while it was above 60 % during 2001–2010. In addition, effect of cropland expansion on damage of cereal aphids was significantly positive, which indicated that cropland expansion in agricultural landscape may enhance pest damage greatly.Finally, we concluded that cropland expansion was one of the most important drivers of increasing pest outbreak,which should be considered in sustainable management of cereal aphids combined with other factor(e.g. climate changes and resistant variety) at large spatiotemporal scale.展开更多
IPv6 has been an inevitable trend with the depletion of the global IPv4 address space. However, new IPv6 users still need public IPv4 addresses to access global IPv4 users/resources, making it important for providers ...IPv6 has been an inevitable trend with the depletion of the global IPv4 address space. However, new IPv6 users still need public IPv4 addresses to access global IPv4 users/resources, making it important for providers to share scarce global IPv4 addresses effectively. There are two categories of solutions to the problem, carrier-grade NAT (CGN) and 'A+P' (each customer shaving the same IPv4 address is assigned an excluded port range). However, both of them have limitations. Specifically, CGN solutions are not scalable and can bring much complexity in managing customers in large-scale deployments, while A+P solutions are not flexible enough to meet dynamic port requirements. In this paper, we propose a hybrid mechanism to improve current solutions and have deployed it in the Tsinghua University Campus Network. The real traffic data shows that our mechanism can utilize limited IPv4 addresses efficiently without degrading the performance of applications on end hosts. Based on the enhanced mechanism, we propose a method to help service providers make address plans based on their own traffic patterns and actual requirements.展开更多
文摘China is setting out on a new journey of building a modern socialist country in all respects after achieving moderate prosperity.Modern services are an important part of China’s economy,underpinning China’s development towards a great modern socialist country.Globalization,industrial development,urbanization,innovation and income growth will drive China’s service sector development.By 2035,the service sector will account for 60.98%and 59.12%of total value-added and employment,respectively,and labor productivity in the service sector will rise from 145,500 yuan/person in 2019 to 282,300 yuan/person.The Fifth Plenum of the 19th CPC Central Committee called for“basically achieving the vision of socialist modernization by 2035.”According to the CPC Central Committee’s overall arrangements for the 2035 vision,we must identify a clear strategic position and tasks for the development of modern services as a key element of the modern industrial system,enhance service sector competitiveness,and achieve service sector modernization.To achieve this strategic goal,we must promote digitalized,intelligent,platform-based,standardized,and quality-oriented service sector development.We must give play to the decisive role of the market and the macro-regulatory role of the government in spurring service innovation,industry integration and clustering,and service sector reform and openness.
基金supported by the Natural Science Foundation of China (71103021, 71573022, 71372193, 71301106)Beijing Philosophy and Social Science Planning Foundation (13JGC085)+1 种基金Beijing Higher Education Yong Elite Teacher Foundation (YETP0852)Humanities and Social Sciences Foundation of the Ministry of Education(13YJC630034, 13YJA790023)
文摘Standard e-government information system(SEIS) including mobile-government applications are playing more and more important roles in the establishing of national e-government framework. It can be beneficial not only for avoiding redundant e-government IS development but also for improving collaboration among government agencies. Two research questions were explored: what are the factors influencing the performance of SEIS? Will mandatory SEIS create a better performance than non-mandatory SEIS? Specifically, the use of five categories of IS aspects--information system quality, online service quality, offline service quality, diffusion modes and standard network size—is proposed to understand the performance of SEIS through applying both survey study and simulation study. The results show that information system quality and online service quality of SEIS have strong effects on users' expectation and users' satisfaction, which thereafter promotes the performance of SEIS. Government agencies' offline service quality shows a significant effect on users' satisfaction while not on users' expectation. Furthermore, the diffusion speed of SEIS in non-mandatory and mandatory modes and the standard network size also have great influence on the utility of SEIS.
基金supported by the National 973 Basic Research Program of China under grant No.2014CB340600the National Natural Science Foundation of China under grant No.61370230 and No.61662022+1 种基金Program for New Century Excellent Talents in University Under grant NCET-13-0241Natural Science Foundation of Huhei Province under Grant No.2016CFB371
文摘In traditional framework,mandatory access control(MAC) system and malicious software are run in kernel mode. Malicious software can stop MAC systems to be started and make it do invalid. This problem cannot be solved under the traditional framework if the operating system(OS) is comprised since malwares are running in ring 0 level. In this paper,we propose a novel way to use hypervisors to protect kernel integrity and the access control system in commodity operating systems. We separate the access control system into three parts: policy management(PM),security server(SS) and policy enforcement(PE). Policy management and the security server reside in the security domain to protect them against malware and the isolation feather of the hypervisor can protect them from attacks. We add an access vector cache(AVC) between SS and PE in the guest OS,in order to speed up communication between the guest OS and the security domain. The policy enforcement module is retained in the guest OS for performance. The security of AVC and PE can be ensured by using a memory protection mechanism. The goal of protecting the OS kernel is to ensure the security of the execution path. We implementthe system by a modified Xen hypervisor. The result shows that we can secure the security of the access control system in the guest OS with no overhead compared with modules in the latter. Our system offers a centralized security policy for virtual domains in virtual machine environments.Keywords: hypervisor; virtualization; memo-
文摘This paper suggests that a new approach should be taken for the development of China's service sector. Priorities for this include: appropriate objectives for service sector development, enhanced functionality, integrated development between manufacturing and services, improved regional layout of the service sector, and the emergence of reputable brands and leading enterprises. Well-designed and effective industrial policies, as well as calls for major breakthroughs in institutional mechanisms, must support the development of the service sector. Additionally, excessive burdens and difficult financing channels need to be addressed. More attention should be paid to the construction of the credit system, service standardization, and service statistical accounting as element tasks.
基金supported by the State Key Laboratory of Integrated Management of Pest Insects and Rodents(IPM1513)the National Natural Science of Foundation China(31400349)the National High Technology Research and Development Program of China(2012BAD19B05)
文摘Landscape-scale pattern could affect ecosystem service such as biocontrol of agricultural pests. Additionally, pest outbreak has been shown to be interwoven with land-use intensity. In the present research, we collected and analysed the 60-year data of cereal aphids and wheat area during 1951–2010 in China. Regression model was applied to analyse the relationship between pest damage and cropland expansion. Results showed that the percentage of cereal aphid outbreak area in wheat area increased rapidly during 1951–2010. It was 9 % during 1951–1960, while it was above 60 % during 2001–2010. In addition, effect of cropland expansion on damage of cereal aphids was significantly positive, which indicated that cropland expansion in agricultural landscape may enhance pest damage greatly.Finally, we concluded that cropland expansion was one of the most important drivers of increasing pest outbreak,which should be considered in sustainable management of cereal aphids combined with other factor(e.g. climate changes and resistant variety) at large spatiotemporal scale.
文摘IPv6 has been an inevitable trend with the depletion of the global IPv4 address space. However, new IPv6 users still need public IPv4 addresses to access global IPv4 users/resources, making it important for providers to share scarce global IPv4 addresses effectively. There are two categories of solutions to the problem, carrier-grade NAT (CGN) and 'A+P' (each customer shaving the same IPv4 address is assigned an excluded port range). However, both of them have limitations. Specifically, CGN solutions are not scalable and can bring much complexity in managing customers in large-scale deployments, while A+P solutions are not flexible enough to meet dynamic port requirements. In this paper, we propose a hybrid mechanism to improve current solutions and have deployed it in the Tsinghua University Campus Network. The real traffic data shows that our mechanism can utilize limited IPv4 addresses efficiently without degrading the performance of applications on end hosts. Based on the enhanced mechanism, we propose a method to help service providers make address plans based on their own traffic patterns and actual requirements.