Recent developments in the aerospace industry have led to a dramatic reduction in the manufacturing and launch costs of low Earth orbit satellites.The new trend enables the paradigm shift of satelliteterrestrial integ...Recent developments in the aerospace industry have led to a dramatic reduction in the manufacturing and launch costs of low Earth orbit satellites.The new trend enables the paradigm shift of satelliteterrestrial integrated networks with global coverage.In particular,the integration of 5G communication systems and satellites has the potential to restructure nextgeneration mobile networks.By leveraging the network function virtualization and network slicing,the satellite 5G core networks will facilitate the coordination and management of network functions in satellite-terrestrial integrated networks.We are the first to deploy a 5G core network on a real-world satellite to investigate its feasibility.We conducted experiments to validate the satellite 5G core network functions.The validated procedures include registration and session setup procedures.The results show that the satellite 5G core network can function normally and generate correct signaling.展开更多
To effectively mitigate the short-term fatigue effects of driving in extra-long tunnels,this study conducted natural driving experiments in five extra-long tunnels of varying lengths and tunnel group sections.Utilizin...To effectively mitigate the short-term fatigue effects of driving in extra-long tunnels,this study conducted natural driving experiments in five extra-long tunnels of varying lengths and tunnel group sections.Utilizing data obtained from natural driving fatigue experiments,this study identified perclos P80,variable coefficient of pupil diameter,and acceleration as fatigue sensitivity indicators,determined through significance tests of difference and correlation analysis.This study employed an ordered multi-class Logistic model to investigate the factors that influence driving fatigue in extra-long tunnels.The most significant variable in the model was perclos P80,which served as an indicator for classifying and identifying fatigue levels in extra-long tunnels.Following this,a dimensionless quantitative metric,the Fatigue Driving Degree,was formulated,and the Threshold of Driving Fatigue was established.Using the quantitative framework for driving fatigue,this paper standardized the definition of the fatigue arousal zone in extra-long tunnels.The study analyzed the operational principles and validated the key parameters of the fatigue arousal zone in extra-long tunnels.These parameters encompass the placement location,length,form,and traffic induction design of the fatigue arousal zone.The research findings can serve as a theoretical reference for the development of fatigue arousal technology in extra-long highway tunnels in China.展开更多
Cloud computing is becoming an important solution for providing scalable computing resources via Internet. Because there are tens of thousands of nodes in data center, the probability of server failures is nontrivial....Cloud computing is becoming an important solution for providing scalable computing resources via Internet. Because there are tens of thousands of nodes in data center, the probability of server failures is nontrivial. Therefore, it is a critical challenge to guarantee the service reliability. Fault-tolerance strategies, such as checkpoint, are commonly employed. Because of the failure of the edge switches, the checkpoint image may become inaccessible. Therefore, current checkpoint-based fault tolerance method cannot achieve the best effect. In this paper, we propose an optimal checkpoint method with edge switch failure-aware. The edge switch failure-aware checkpoint method includes two algorithms. The first algorithm employs the data center topology and communication characteristic for checkpoint image storage server selection. The second algorithm employs the checkpoint image storage characteristic as well as the data center topology to select the recovery server. Simulation experiments are performed to demonstrate the effectiveness of the proposed method.展开更多
Nowadays scalable Io T management is a bottleneck of Io T development due to the geographically dispersed distribution, fragmented ownerships, and ever-growing population of Io T devices. To intelligently manage massi...Nowadays scalable Io T management is a bottleneck of Io T development due to the geographically dispersed distribution, fragmented ownerships, and ever-growing population of Io T devices. To intelligently manage massive decentralized applications(d Apps) in Io T usecases, Edgence(EDGe + intellig ENCE) is proposed to use edge clouds to access Io T devices and users, and then use its in-built blockchain to realize self-governing and self-supervision of the edge clouds. Edgence proposes to use masternode technology to introduce Io T devices and users into a closed blockchain system, which can extend the range of blockchain to Io T-based d Apps. Further, masternodes do good to scalability by raising the TPS(transactions per second) of the blockchain network. To support various d Apps, a three-tier validation is proposed, namely script validation, smartcontract validation, and masternode validation. To avoid energy consumption resulted by blockchain consensus, Edgence proposes a random but verifiable way to elect a masternode to generate each new block. The potential of the tailored Edgence is shown by examples of decentralized crowdsourcing and AI training.展开更多
Agriculture is the foundation of the national economy. On the one hand,there is increasing demand for fresh and safe refrigerated agricultural products; on the other hand,the current cold chain logistics is relatively...Agriculture is the foundation of the national economy. On the one hand,there is increasing demand for fresh and safe refrigerated agricultural products; on the other hand,the current cold chain logistics is relatively underdeveloped and has many problems. This paper does a research on the major large-scale agricultural cold-chain logistics companies in Chongqing,and finds that cold-chain logistics in Chongqing has some problems such as incomplete industrial chain,relatively backward infrastructure,lack of talents,and high logistics costs. Some solutions to these problems are put forward: improving chain logistics infrastructure; strengthening personnel training; building information platform to create a new model of the cold-chain logistics in the Internet era; seeking government's policy and financial support.展开更多
In the current cloud-based Internet-of-Things(Io T)model,smart devices(such as sensors,smartphones)exchange information through the Internet to cooperate and provide services to users,which could be citizens,smart hom...In the current cloud-based Internet-of-Things(Io T)model,smart devices(such as sensors,smartphones)exchange information through the Internet to cooperate and provide services to users,which could be citizens,smart home systems,and industrial applications.As a result,Fog computing is a new paradigm that entitle展开更多
Chemical functionalization is an effective approach to address interfacial deterioration caused by environmental exposure in cellulose nanofiber(CNF)-epoxy nanocomposites.However,how functionalization affects interfac...Chemical functionalization is an effective approach to address interfacial deterioration caused by environmental exposure in cellulose nanofiber(CNF)-epoxy nanocomposites.However,how functionalization affects interfacial deterioration and durability of nanocomposites in erosive environment is still lacked.In this work,the global mechanical properties and local interfacial intermolecular behavior of pristine and functionalized CNF-reinforced nanocomposites are investigated through molecular dynamics simulations.The results show that functionalization can enhance the interfacial energy barrier and debonding stress by 43%and 57%,respectively.Functionalized CNF inhibits the slippage of epoxy chains,ensuring better interfacial adhesion and efficient stress transfer between fiber and matrix.Functional groups promote the formation of interfacial bridging and topological structures and weaken the hydrogen bonding ability of water molecules,leading to stronger intermolecular adsorption effect and better interfacial integrity.The epoxy molecular configuration evolution and intermolecular interactions,caused by the functionalization of CNF in the interfacial region,enhance the interfacial erosion resistance,contributing to the durability of the nanocomposites.This study reveals the in-depth interfacial deterioration mechanism of functionalized nanocomposites under erosive environment,inspiring a novel strategy for the design of durable CNF-reinforced nanocomposites.展开更多
Since service level agreement(SLA)is essentially used to maintain reliable quality of service between cloud providers and clients in cloud environment,there has been a growing effort in reducing power consumption whil...Since service level agreement(SLA)is essentially used to maintain reliable quality of service between cloud providers and clients in cloud environment,there has been a growing effort in reducing power consumption while complying with the SLA by maximizing physical machine(PM)-level utilization and load balancing techniques in infrastructure as a service.However,with the recent introduction of container as a service by cloud providers,containers are increasingly popular and will become the major deployment model in the cloud environment and specifically in platform as a service.Therefore,reducing power consumption while complying with the SLA at virtual machine(VM)-level becomes essential.In this context,we exploit a container consolidation scheme with usage prediction to achieve the above objectives.To obtain a reliable characterization of overutilized and underutilized PMs,our scheme jointly exploits the current and predicted CPU utilization based on local history of the considered PMs in the process of the container consolidation.We demonstrate our solution through simulations on real workloads.The experimental results show that the container consolidation scheme with usage prediction reduces the power consumption,number of container migrations,and average number of active VMs while complying with the SLA.展开更多
基金supported by the National Key R&D Program of China(2020YFB1805500)National Natural Science Foundation of China(61922017,62032003 and 61921003)。
文摘Recent developments in the aerospace industry have led to a dramatic reduction in the manufacturing and launch costs of low Earth orbit satellites.The new trend enables the paradigm shift of satelliteterrestrial integrated networks with global coverage.In particular,the integration of 5G communication systems and satellites has the potential to restructure nextgeneration mobile networks.By leveraging the network function virtualization and network slicing,the satellite 5G core networks will facilitate the coordination and management of network functions in satellite-terrestrial integrated networks.We are the first to deploy a 5G core network on a real-world satellite to investigate its feasibility.We conducted experiments to validate the satellite 5G core network functions.The validated procedures include registration and session setup procedures.The results show that the satellite 5G core network can function normally and generate correct signaling.
基金This research was sponsored by Natural Science Foundation of Chongqing,China(grant number CSTB2023NSCQ-MSX0742)by the MOE(Ministry of Education in China)Project of Humanities and Social Sciences(grant number 22YJCZH143)by the National Natural Science Foundation of China(General Program)(grant number 52172341).
文摘To effectively mitigate the short-term fatigue effects of driving in extra-long tunnels,this study conducted natural driving experiments in five extra-long tunnels of varying lengths and tunnel group sections.Utilizing data obtained from natural driving fatigue experiments,this study identified perclos P80,variable coefficient of pupil diameter,and acceleration as fatigue sensitivity indicators,determined through significance tests of difference and correlation analysis.This study employed an ordered multi-class Logistic model to investigate the factors that influence driving fatigue in extra-long tunnels.The most significant variable in the model was perclos P80,which served as an indicator for classifying and identifying fatigue levels in extra-long tunnels.Following this,a dimensionless quantitative metric,the Fatigue Driving Degree,was formulated,and the Threshold of Driving Fatigue was established.Using the quantitative framework for driving fatigue,this paper standardized the definition of the fatigue arousal zone in extra-long tunnels.The study analyzed the operational principles and validated the key parameters of the fatigue arousal zone in extra-long tunnels.These parameters encompass the placement location,length,form,and traffic induction design of the fatigue arousal zone.The research findings can serve as a theoretical reference for the development of fatigue arousal technology in extra-long highway tunnels in China.
基金supported by Beijing Natural Science Foundation (4174100)NSFC(61602054)the Fundamental Research Funds for the Central Universities
文摘Cloud computing is becoming an important solution for providing scalable computing resources via Internet. Because there are tens of thousands of nodes in data center, the probability of server failures is nontrivial. Therefore, it is a critical challenge to guarantee the service reliability. Fault-tolerance strategies, such as checkpoint, are commonly employed. Because of the failure of the edge switches, the checkpoint image may become inaccessible. Therefore, current checkpoint-based fault tolerance method cannot achieve the best effect. In this paper, we propose an optimal checkpoint method with edge switch failure-aware. The edge switch failure-aware checkpoint method includes two algorithms. The first algorithm employs the data center topology and communication characteristic for checkpoint image storage server selection. The second algorithm employs the checkpoint image storage characteristic as well as the data center topology to select the recovery server. Simulation experiments are performed to demonstrate the effectiveness of the proposed method.
基金supported in part by the National Science Foundation of China(Grant No.61922017).
文摘Nowadays scalable Io T management is a bottleneck of Io T development due to the geographically dispersed distribution, fragmented ownerships, and ever-growing population of Io T devices. To intelligently manage massive decentralized applications(d Apps) in Io T usecases, Edgence(EDGe + intellig ENCE) is proposed to use edge clouds to access Io T devices and users, and then use its in-built blockchain to realize self-governing and self-supervision of the edge clouds. Edgence proposes to use masternode technology to introduce Io T devices and users into a closed blockchain system, which can extend the range of blockchain to Io T-based d Apps. Further, masternodes do good to scalability by raising the TPS(transactions per second) of the blockchain network. To support various d Apps, a three-tier validation is proposed, namely script validation, smartcontract validation, and masternode validation. To avoid energy consumption resulted by blockchain consensus, Edgence proposes a random but verifiable way to elect a masternode to generate each new block. The potential of the tailored Edgence is shown by examples of decentralized crowdsourcing and AI training.
基金Supported by Fundamental Research Funds for the Central Universities(XDJK2013C080)Humanities and Social Sciences Project of Southwest University(13SWUDJJD14)Fundamental Research Funds for the Central Universities(SWU1409141)
文摘Agriculture is the foundation of the national economy. On the one hand,there is increasing demand for fresh and safe refrigerated agricultural products; on the other hand,the current cold chain logistics is relatively underdeveloped and has many problems. This paper does a research on the major large-scale agricultural cold-chain logistics companies in Chongqing,and finds that cold-chain logistics in Chongqing has some problems such as incomplete industrial chain,relatively backward infrastructure,lack of talents,and high logistics costs. Some solutions to these problems are put forward: improving chain logistics infrastructure; strengthening personnel training; building information platform to create a new model of the cold-chain logistics in the Internet era; seeking government's policy and financial support.
文摘In the current cloud-based Internet-of-Things(Io T)model,smart devices(such as sensors,smartphones)exchange information through the Internet to cooperate and provide services to users,which could be citizens,smart home systems,and industrial applications.As a result,Fog computing is a new paradigm that entitle
基金supported by the National Key Research and Development Program of China(No.2021YFF0500802)the National Science Fund for Distinguished Young Scholars(No.52025081)+2 种基金Key Research and Development Program of Guangdong Province(No.2019B111107001)Shenzhen Science and Technology Programs(No.RCBS20200714114819352)Foundation for Distinguished Young Talents in Higher Education of Guangdong(No.2021KQNCX096).
文摘Chemical functionalization is an effective approach to address interfacial deterioration caused by environmental exposure in cellulose nanofiber(CNF)-epoxy nanocomposites.However,how functionalization affects interfacial deterioration and durability of nanocomposites in erosive environment is still lacked.In this work,the global mechanical properties and local interfacial intermolecular behavior of pristine and functionalized CNF-reinforced nanocomposites are investigated through molecular dynamics simulations.The results show that functionalization can enhance the interfacial energy barrier and debonding stress by 43%and 57%,respectively.Functionalized CNF inhibits the slippage of epoxy chains,ensuring better interfacial adhesion and efficient stress transfer between fiber and matrix.Functional groups promote the formation of interfacial bridging and topological structures and weaken the hydrogen bonding ability of water molecules,leading to stronger intermolecular adsorption effect and better interfacial integrity.The epoxy molecular configuration evolution and intermolecular interactions,caused by the functionalization of CNF in the interfacial region,enhance the interfacial erosion resistance,contributing to the durability of the nanocomposites.This study reveals the in-depth interfacial deterioration mechanism of functionalized nanocomposites under erosive environment,inspiring a novel strategy for the design of durable CNF-reinforced nanocomposites.
基金The work presented in this paper was supported by the NSFC(Grant Nos.61472047 and 61602054)Beijing Natural Science Foundation(4174100).
文摘Since service level agreement(SLA)is essentially used to maintain reliable quality of service between cloud providers and clients in cloud environment,there has been a growing effort in reducing power consumption while complying with the SLA by maximizing physical machine(PM)-level utilization and load balancing techniques in infrastructure as a service.However,with the recent introduction of container as a service by cloud providers,containers are increasingly popular and will become the major deployment model in the cloud environment and specifically in platform as a service.Therefore,reducing power consumption while complying with the SLA at virtual machine(VM)-level becomes essential.In this context,we exploit a container consolidation scheme with usage prediction to achieve the above objectives.To obtain a reliable characterization of overutilized and underutilized PMs,our scheme jointly exploits the current and predicted CPU utilization based on local history of the considered PMs in the process of the container consolidation.We demonstrate our solution through simulations on real workloads.The experimental results show that the container consolidation scheme with usage prediction reduces the power consumption,number of container migrations,and average number of active VMs while complying with the SLA.
