To improve data distribution efficiency a load-balancing data distribution LBDD method is proposed in publish/subscribe mode.In the LBDD method subscribers are involved in distribution tasks and data transfers while r...To improve data distribution efficiency a load-balancing data distribution LBDD method is proposed in publish/subscribe mode.In the LBDD method subscribers are involved in distribution tasks and data transfers while receiving data themselves.A dissemination tree is constructed among the subscribers based on MD5 where the publisher acts as the root. The proposed method provides bucket construction target selection and path updates furthermore the property of one-way dissemination is proven.That the average out-going degree of a node is 2 is guaranteed with the proposed LBDD.The experiments on data distribution delay data distribution rate and load distribution are conducted. Experimental results show that the LBDD method aids in shaping the task load between the publisher and subscribers and outperforms the point-to-point approach.展开更多
Publish/subscribe paradigm paves a way to integrate and serve many scalable, inter-operable Internet of Things(IoT) applications. The increasing IoT applications require new properties of publish/subscribe communicati...Publish/subscribe paradigm paves a way to integrate and serve many scalable, inter-operable Internet of Things(IoT) applications. The increasing IoT applications require new properties of publish/subscribe communication model, for example, strict quality of service(Qo S) guarantees, supporting a large number of widely distributed devices, etc. Software Defined Networking(SDN) enables personalized programming and individualized QoS supports for different applications. The combination of the two will have a good prospect. In this paper, we present an IoT-oriented communication platform which combines the publish/subscribe paradigm with SDN, aiming at establishing an IoT ecosystem to facilitate IoT services/applications accessing internet. We design the interaction logic of topic-based publish/subscribe middleware, and describe the setup and maintenance of topology information as well as event routing in detail, considering the characteristics of SDN. Finally, we exemplify its practicability with a deployed District Heating Control and Information Service System(DHCISS) and validity the effectiveness with some experiments.展开更多
Publish/subscribe paradigm is often adopted to create the communication infrastructure of the Internet of Things(IoT)for many clients to access enormous real-time sensor data.However,most current publish/subscribe mid...Publish/subscribe paradigm is often adopted to create the communication infrastructure of the Internet of Things(IoT)for many clients to access enormous real-time sensor data.However,most current publish/subscribe middlewares are based on traditional ossified IP networks,which are difficult to enable Quality of Service(QoS).How to design the next generation publish/subscribe middleware has become an urgent problem.The emerging Software Defined Networking(SDN)provides new opportunities to improve the QoS of publish/subscribe facilities for delivering events in IoT owing to its customized programmability and centralized control.We can encode event topics,priorities and security policies into flow entries of SDN-enabled switches to satisfy personalized QoS needs.In this paper,we propose a cross-layer QoS enabled SDN-like publish/subscribe communication infrastructure,aiming at building an IoT platform to seamlessly connect IoT services with SDN networks and improving the QoS of delivering events.We first present an SDN-like topic-oriented publish/subscribe middleware architecture with a cross-layer QoS control framework.Then we discuss prototype implementation,including topic management,topology maintenance,event routing and policy management.In the end,we use differentiated services and cross-layer access control as cross-layer QoS scenarios to verify the prototype.Experimental results show that our middleware is effective.展开更多
The margin maximization problem in digital subscriber line（DSL） systems is investigated.The particle swarm optimization（PSO） theory is applied to the nonconvex margin optimization problem with the target power and...The margin maximization problem in digital subscriber line（DSL） systems is investigated.The particle swarm optimization（PSO） theory is applied to the nonconvex margin optimization problem with the target power and rate constraints.PSO is a new evolution algorithm based on the social behavior of swarms, which can solve discontinuous, nonconvex and nonlinear problems efficiently.The proposed algorithm can converge to the global optimal solution, and numerical example demonstrates that the proposed algorithm can guarantee the fast convergence within a few iterations.展开更多
With the rapid development of wireless local area network （WLAN） technology, an important target of indoor positioning systems is to improve the positioning accuracy while reducing the online calibration effort to o...With the rapid development of wireless local area network （WLAN） technology, an important target of indoor positioning systems is to improve the positioning accuracy while reducing the online calibration effort to overcome signal time-varying. A novel fingerprint positioning algorithm, known as the adaptive radio map with updated method based on hidden Markov model （HMM）, is proposed. It is shown that by using a collection of user traces that can be cheaply obtained, the proposed algorithm can take advantage of these data to update the labeled calibration data to further improve the position estimation accuracy. This algorithm is a combination of machine learning, information gain theory and fingerprinting. By collecting data and testing the algorithm in a realistic indoor WLAN environment, the experiment results indicate that, compared with the widely used K nearest neighbor algorithm, the proposed algorithm can improve the positioning accuracy while greatly reduce the calibration effort.展开更多
Cooperation allows wireless network users to benefit from various gains such as an in- crease in the achieved rate or an improvement in the bit error rate. In the paper, we propose a distributed Hierarchical Game （HG...Cooperation allows wireless network users to benefit from various gains such as an in- crease in the achieved rate or an improvement in the bit error rate. In the paper, we propose a distributed Hierarchical Game （HG） theoretic framework over multi-user cooperative communication networks to stimulate cooperation and improve the network performance. First, we study a two- user decision making game in the OFDMA based subscriber cooperative relaying network, in which subscribers transmit their own data in the first phase, while helping to retransmit their partner＇s or choosing to freeride in the second phase. Instead of consulting to a global optimal solution, we decouple the cooperation resource allocation into two level subproblems： a user level Nash game for distributed cooperation decision and a Base Station （BS） level coalition game for centralized resource allocation. In the proposed HG algorithm, where mutual cooperation is preferred and total payoff is transferable, we prove it converges to a unique optimal equilibrium and resolve the subcarrier as-signment and power allocation among the couples. Besides, we discuss the existence of the publishing and rewarding coefficients in order to encourage cooperation. Then, we extend the HG to multi-user cases by coupling among subscribers according to the location information. The simulation results show that the proposed scheme with the distributed HG game achieves a well tradeoff between fairness and efficiency by improving the transmission efficiency of adverse users and outperforms those employing centralized schemes.展开更多
柑橘作为世界上重要经济作物之一,随着生产规模的扩大,病虫害日益成为制约其发展的瓶颈。在为害柑橘的众多害虫中,柑橘木虱Diaphorina citri Kuwayama为害最为严重,其成虫和若虫不仅能直接刺吸为害柑橘、柠檬等芸香科植物,还是传播柑橘...柑橘作为世界上重要经济作物之一,随着生产规模的扩大,病虫害日益成为制约其发展的瓶颈。在为害柑橘的众多害虫中,柑橘木虱Diaphorina citri Kuwayama为害最为严重,其成虫和若虫不仅能直接刺吸为害柑橘、柠檬等芸香科植物,还是传播柑橘黄龙病(Huanglongbing,HLB)的重要媒介。“Push-Pull”策略作为害虫生态调控(Ecological regulation and management of pests,ERMP)中的一项重要技术,具有“经济、简便、有效、绿色”等优点。通过推广普及“Push-Pull”技术,将有助于控制柑橘木虱的为害,推动我国柑橘产业绿色发展。本文以综述“Push-Pull”策略为例,分别介绍了“Push”和“Pull”两个组分的研究进展,展望“Push-Pull”策略在防治柑橘木虱的发展应用,希望能为柑橘生产过程中经济、简便、有效地治理柑橘木虱提供理论参考和技术支撑,推动我国柑橘产业健康可持续发展。展开更多
Providing end-to-end delay guarantees in traditional Internet is a complex task due to the distributed nature of TCP/IP protocols. Software Defined Networking(SDN) gives a new dimension to improve QoS(Quality of Servi...Providing end-to-end delay guarantees in traditional Internet is a complex task due to the distributed nature of TCP/IP protocols. Software Defined Networking(SDN) gives a new dimension to improve QoS(Quality of Service) as it can benefit from its flexibility, programmability and centralized view. In this paper, we provide delay-guaranteed data transmission service instead of "best efforts" service for a topic-based publish/subscribe system by means of exploring these specific features of SDN. We attribute this routing problem in such conditions to Delay-Constraint Lowest Cost Steiner Tree(DCLCST) problem. To solve it, we compute the shortest delay paths from source node to every subscribe node and the shortest cost paths from every subscribe node to any other node using dijkstra algorithm. Then we construct a delay-constraint least cost steiner tree for per-topic based on these paths as multicast tree. We also present experimental results to demonstrate the effectiveness of the algorithms and methods we proposed.展开更多
Standard based Pub/Sub middleware, such as OMG Data Distribution Service (DDS), could assume a key role in supporting computer communications requiring continuous state information updating, deterministic deadline to ...Standard based Pub/Sub middleware, such as OMG Data Distribution Service (DDS), could assume a key role in supporting computer communications requiring continuous state information updating, deterministic deadline to data delivering and real time information adjourning. This kind of capability could be well ex-ploited by Peer-To-Peer (P2P) systems, Internet-wide as long as private ones, like in Public Safety or Civil Protection Communication Systems;but Pub/Sub specifications, and DDS/RTPS (Real Time Publish Sub-scribe) as well, usually do not provide Authentication & Authorization (AA) mechanisms. In the present work two important novelties are assessed: a possible scheme to implement AA in DDS/RTPS networks and a time performance evaluation study about embedded Authentication in RTPS.展开更多
Wireless sensor network nodes have only limited resources concerning memory and battery life-time. Mem- ory can be efficiently used by sharing data, and the life-time of a battery can be extended, when the node has lo...Wireless sensor network nodes have only limited resources concerning memory and battery life-time. Mem- ory can be efficiently used by sharing data, and the life-time of a battery can be extended, when the node has long power saving sleep-phases. We propose a publish/subscribe architecture that achieves these two aims. The results of our work are of great interest for sensor application developers, giving them now the opportu- nity to use our architecture for sharing data among different applications on the node as well as the different layers of the operating system. We introduce a blackboard which is used for centrally storing published val- ues, like measured data from a monitored sensor. This makes it possible to share stored data without monitoring the sensors once again, which is advantageously concerning power consumption, memory space, and reaction time. Beside the proposed publish/subscribe method for sensor nodes with its notification possibili- ties, our architecture fulfills also real-time requirements. We show how the well-known sensor operating system MANTIS OS can be extended by a real-time enabled, blackboard-based publish/subscribe architect- ture. This architecture and first of all its implementation is of special interest for cross layer optimization of sensor applications. Cross-layer approaches benefit from our architecture because the available implementa- tion can be used as an efficient framework for central storing and managing of shared values.展开更多
WS-Notification bundle of standards, WS-BaseNotification, WS-Topics, and WS-BrokeredNotification, can be used as a general purpose publish/subscribe interface for Service Oriented Architectures. We provide an overview...WS-Notification bundle of standards, WS-BaseNotification, WS-Topics, and WS-BrokeredNotification, can be used as a general purpose publish/subscribe interface for Service Oriented Architectures. We provide an overview of the WS-Notification specification and describe a modified publish and subscribe model based on WS-Notification. The model is an adaptive policy-driven notification framework that can help enterprises to meet the flexibility and respon-siveness requirements of the enterprise. With the modified publish/subscribe model, information consumers can dy-namically and declaratively create and configure entities on their behalves to manage their distribution requirements.展开更多
Transactions of Nanjing University of Aeronautics & Astronautics (TNUAA, in English) is a comprehensive academic publication which deals mainly with the research achievements in aeronautics, civil aviation, astron...Transactions of Nanjing University of Aeronautics & Astronautics (TNUAA, in English) is a comprehensive academic publication which deals mainly with the research achievements in aeronautics, civil aviation, astronautics and their theoretical basis. It is published by Nanjing University of Aeronautics & Astronautics, and has started its publication since Oct.展开更多
Connected vehicles for safety and traffic efficient applications require device-to-device connections supporting one-to-many and many-to-many communication, precise absolute and relative positioning and distributed co...Connected vehicles for safety and traffic efficient applications require device-to-device connections supporting one-to-many and many-to-many communication, precise absolute and relative positioning and distributed computing. Currently, the 5.9 GHz Dedicated Short Range Communications (DSRC) and 4G-Long-Term Evolution (LTE) are available for connected vehicle services. But both have limitations in reliability or latency over large scale field operational tests and deployment. This paper proposes the device-to-device (D2D) connectivity framework based on publish-subscribe architecture, with Message Queue Telemetry Transport (MQTT) protocol. With the publish-subscribe communication paradigm, road mobile users can exchange data and information in moderate latency and high reliability manner, having the potential to support many Vehicle to Everything (V2X) applications, including vehicle to vehicle (V2V), vehicle to roadside infrastructure (V2I), and vehicle to bicycle (V2B). The D2D data exchanges also facilitate computing for absolute and relative precise real-time kinematic (RTK) posi-tioning. Vehicular experiments were conducted to evaluate the performance of the proposed publish-subscribe MQTT protocols in term of latency and reliability. The latency of data exchanges is measured by One-trip-time (OTT) and the reliability is measured by the packet loss rate (PLR). Our results show that the latency of GNSS raw data exchanges between vehicles through 4G cellular networks at the rate of 10 Hz and the data rates of 10 kbps are less than 300 ms while the reliability is over 96%. Vehicular positioning experiments have also shown that vehicles can exchange raw GNSS data and complete mov-ing-base RTK positioning with the positioning availability of 98%.展开更多
Machinery of China is an export-oriented authoritative magazine of the Ministry of Machinebuilding Industry, read by tens of thousands of directors and managers of electrical and machinery enterprises in China. It is ...Machinery of China is an export-oriented authoritative magazine of the Ministry of Machinebuilding Industry, read by tens of thousands of directors and managers of electrical and machinery enterprises in China. It is published at home and abroad. It offers introductions to national and ministry policies and regulations concernmg the industry,provides authoritative industry statistics and accurately forecasts market trends for electrical and machinery products. In addition,展开更多
Journal of Rock Mechanics and Geotechnical Engineering（JRMGE）is a new academic publication in English launched in 2009,co-sponsored by Institute of Rock and Soil Mechanics,China Academy of Sciences,Chinese Society f...Journal of Rock Mechanics and Geotechnical Engineering（JRMGE）is a new academic publication in English launched in 2009,co-sponsored by Institute of Rock and Soil Mechanics,China Academy of Sciences,Chinese Society for Rock Mechanics and Engineering and Wuhan University.展开更多
Rural revitalization was a major focus during this year’s“two sessions.”THE drive to advance China’s all-around rural revitalization comprises advances in agriculture,revitalization of rural areas,and well-being o...Rural revitalization was a major focus during this year’s“two sessions.”THE drive to advance China’s all-around rural revitalization comprises advances in agriculture,revitalization of rural areas,and well-being of rural residents–the“three rural work,”as emphasized by Premier Li Qiang in the 2025 government work report.展开更多
基金The National Key Basic Research Program of China(973 Program)
文摘To improve data distribution efficiency a load-balancing data distribution LBDD method is proposed in publish/subscribe mode.In the LBDD method subscribers are involved in distribution tasks and data transfers while receiving data themselves.A dissemination tree is constructed among the subscribers based on MD5 where the publisher acts as the root. The proposed method provides bucket construction target selection and path updates furthermore the property of one-way dissemination is proven.That the average out-going degree of a node is 2 is guaranteed with the proposed LBDD.The experiments on data distribution delay data distribution rate and load distribution are conducted. Experimental results show that the LBDD method aids in shaping the task load between the publisher and subscribers and outperforms the point-to-point approach.
基金supported by National Hightech R&D Program of China (863 Program) under Grant (No. 2013AA102301)Natural Science Foundation of China under Grant (No. U1536112)
文摘Publish/subscribe paradigm paves a way to integrate and serve many scalable, inter-operable Internet of Things(IoT) applications. The increasing IoT applications require new properties of publish/subscribe communication model, for example, strict quality of service(Qo S) guarantees, supporting a large number of widely distributed devices, etc. Software Defined Networking(SDN) enables personalized programming and individualized QoS supports for different applications. The combination of the two will have a good prospect. In this paper, we present an IoT-oriented communication platform which combines the publish/subscribe paradigm with SDN, aiming at establishing an IoT ecosystem to facilitate IoT services/applications accessing internet. We design the interaction logic of topic-based publish/subscribe middleware, and describe the setup and maintenance of topology information as well as event routing in detail, considering the characteristics of SDN. Finally, we exemplify its practicability with a deployed District Heating Control and Information Service System(DHCISS) and validity the effectiveness with some experiments.
基金the National Key Research and Development Program of China(No.2018YFB1003800).
文摘Publish/subscribe paradigm is often adopted to create the communication infrastructure of the Internet of Things(IoT)for many clients to access enormous real-time sensor data.However,most current publish/subscribe middlewares are based on traditional ossified IP networks,which are difficult to enable Quality of Service(QoS).How to design the next generation publish/subscribe middleware has become an urgent problem.The emerging Software Defined Networking(SDN)provides new opportunities to improve the QoS of publish/subscribe facilities for delivering events in IoT owing to its customized programmability and centralized control.We can encode event topics,priorities and security policies into flow entries of SDN-enabled switches to satisfy personalized QoS needs.In this paper,we propose a cross-layer QoS enabled SDN-like publish/subscribe communication infrastructure,aiming at building an IoT platform to seamlessly connect IoT services with SDN networks and improving the QoS of delivering events.We first present an SDN-like topic-oriented publish/subscribe middleware architecture with a cross-layer QoS control framework.Then we discuss prototype implementation,including topic management,topology maintenance,event routing and policy management.In the end,we use differentiated services and cross-layer access control as cross-layer QoS scenarios to verify the prototype.Experimental results show that our middleware is effective.
基金supported by the National Natural Science Foundation of China for Distinguished Young Scholars (60525303)the National Natural Science Foundation of China (60904048+2 种基金 60404022 60604012)the Natural Science Foundation of Hebei province (F2005000390)
文摘The margin maximization problem in digital subscriber line（DSL） systems is investigated.The particle swarm optimization（PSO） theory is applied to the nonconvex margin optimization problem with the target power and rate constraints.PSO is a new evolution algorithm based on the social behavior of swarms, which can solve discontinuous, nonconvex and nonlinear problems efficiently.The proposed algorithm can converge to the global optimal solution, and numerical example demonstrates that the proposed algorithm can guarantee the fast convergence within a few iterations.
基金supported by the National Natural Science Foundation of China(61571162)the Major National Science and Technology Project(2014ZX03004003-005)
文摘With the rapid development of wireless local area network （WLAN） technology, an important target of indoor positioning systems is to improve the positioning accuracy while reducing the online calibration effort to overcome signal time-varying. A novel fingerprint positioning algorithm, known as the adaptive radio map with updated method based on hidden Markov model （HMM）, is proposed. It is shown that by using a collection of user traces that can be cheaply obtained, the proposed algorithm can take advantage of these data to update the labeled calibration data to further improve the position estimation accuracy. This algorithm is a combination of machine learning, information gain theory and fingerprinting. By collecting data and testing the algorithm in a realistic indoor WLAN environment, the experiment results indicate that, compared with the widely used K nearest neighbor algorithm, the proposed algorithm can improve the positioning accuracy while greatly reduce the calibration effort.
基金Acknowledgements This work is supported by the National Natural Science Foundation of China under Grant No. 60971083, National High-Tech Research and Development Plan of China under Grant No. 2009AA01Z206 and National International Science and Technology Cooperation Project under Granted NO.2008DFA12090.
文摘Cooperation allows wireless network users to benefit from various gains such as an in- crease in the achieved rate or an improvement in the bit error rate. In the paper, we propose a distributed Hierarchical Game （HG） theoretic framework over multi-user cooperative communication networks to stimulate cooperation and improve the network performance. First, we study a two- user decision making game in the OFDMA based subscriber cooperative relaying network, in which subscribers transmit their own data in the first phase, while helping to retransmit their partner＇s or choosing to freeride in the second phase. Instead of consulting to a global optimal solution, we decouple the cooperation resource allocation into two level subproblems： a user level Nash game for distributed cooperation decision and a Base Station （BS） level coalition game for centralized resource allocation. In the proposed HG algorithm, where mutual cooperation is preferred and total payoff is transferable, we prove it converges to a unique optimal equilibrium and resolve the subcarrier as-signment and power allocation among the couples. Besides, we discuss the existence of the publishing and rewarding coefficients in order to encourage cooperation. Then, we extend the HG to multi-user cases by coupling among subscribers according to the location information. The simulation results show that the proposed scheme with the distributed HG game achieves a well tradeoff between fairness and efficiency by improving the transmission efficiency of adverse users and outperforms those employing centralized schemes.
文摘柑橘作为世界上重要经济作物之一,随着生产规模的扩大,病虫害日益成为制约其发展的瓶颈。在为害柑橘的众多害虫中,柑橘木虱Diaphorina citri Kuwayama为害最为严重,其成虫和若虫不仅能直接刺吸为害柑橘、柠檬等芸香科植物,还是传播柑橘黄龙病(Huanglongbing,HLB)的重要媒介。“Push-Pull”策略作为害虫生态调控(Ecological regulation and management of pests,ERMP)中的一项重要技术,具有“经济、简便、有效、绿色”等优点。通过推广普及“Push-Pull”技术,将有助于控制柑橘木虱的为害,推动我国柑橘产业绿色发展。本文以综述“Push-Pull”策略为例,分别介绍了“Push”和“Pull”两个组分的研究进展,展望“Push-Pull”策略在防治柑橘木虱的发展应用,希望能为柑橘生产过程中经济、简便、有效地治理柑橘木虱提供理论参考和技术支撑,推动我国柑橘产业健康可持续发展。
基金supported in part by the National Natural Science Foundation of China under Grants U1804164, 61902112 and U1404602in part by the Science and Technology Foundation of Henan Educational Committee under Grants 19A510015, 20A520019 and 20A520020the Doctoral Research Project of Henan Normal University under Grant 5101119170149
文摘Providing end-to-end delay guarantees in traditional Internet is a complex task due to the distributed nature of TCP/IP protocols. Software Defined Networking(SDN) gives a new dimension to improve QoS(Quality of Service) as it can benefit from its flexibility, programmability and centralized view. In this paper, we provide delay-guaranteed data transmission service instead of "best efforts" service for a topic-based publish/subscribe system by means of exploring these specific features of SDN. We attribute this routing problem in such conditions to Delay-Constraint Lowest Cost Steiner Tree(DCLCST) problem. To solve it, we compute the shortest delay paths from source node to every subscribe node and the shortest cost paths from every subscribe node to any other node using dijkstra algorithm. Then we construct a delay-constraint least cost steiner tree for per-topic based on these paths as multicast tree. We also present experimental results to demonstrate the effectiveness of the algorithms and methods we proposed.
文摘Standard based Pub/Sub middleware, such as OMG Data Distribution Service (DDS), could assume a key role in supporting computer communications requiring continuous state information updating, deterministic deadline to data delivering and real time information adjourning. This kind of capability could be well ex-ploited by Peer-To-Peer (P2P) systems, Internet-wide as long as private ones, like in Public Safety or Civil Protection Communication Systems;but Pub/Sub specifications, and DDS/RTPS (Real Time Publish Sub-scribe) as well, usually do not provide Authentication & Authorization (AA) mechanisms. In the present work two important novelties are assessed: a possible scheme to implement AA in DDS/RTPS networks and a time performance evaluation study about embedded Authentication in RTPS.
文摘Wireless sensor network nodes have only limited resources concerning memory and battery life-time. Mem- ory can be efficiently used by sharing data, and the life-time of a battery can be extended, when the node has long power saving sleep-phases. We propose a publish/subscribe architecture that achieves these two aims. The results of our work are of great interest for sensor application developers, giving them now the opportu- nity to use our architecture for sharing data among different applications on the node as well as the different layers of the operating system. We introduce a blackboard which is used for centrally storing published val- ues, like measured data from a monitored sensor. This makes it possible to share stored data without monitoring the sensors once again, which is advantageously concerning power consumption, memory space, and reaction time. Beside the proposed publish/subscribe method for sensor nodes with its notification possibili- ties, our architecture fulfills also real-time requirements. We show how the well-known sensor operating system MANTIS OS can be extended by a real-time enabled, blackboard-based publish/subscribe architect- ture. This architecture and first of all its implementation is of special interest for cross layer optimization of sensor applications. Cross-layer approaches benefit from our architecture because the available implementa- tion can be used as an efficient framework for central storing and managing of shared values.
文摘WS-Notification bundle of standards, WS-BaseNotification, WS-Topics, and WS-BrokeredNotification, can be used as a general purpose publish/subscribe interface for Service Oriented Architectures. We provide an overview of the WS-Notification specification and describe a modified publish and subscribe model based on WS-Notification. The model is an adaptive policy-driven notification framework that can help enterprises to meet the flexibility and respon-siveness requirements of the enterprise. With the modified publish/subscribe model, information consumers can dy-namically and declaratively create and configure entities on their behalves to manage their distribution requirements.
文摘Transactions of Nanjing University of Aeronautics & Astronautics (TNUAA, in English) is a comprehensive academic publication which deals mainly with the research achievements in aeronautics, civil aviation, astronautics and their theoretical basis. It is published by Nanjing University of Aeronautics & Astronautics, and has started its publication since Oct.
文摘Connected vehicles for safety and traffic efficient applications require device-to-device connections supporting one-to-many and many-to-many communication, precise absolute and relative positioning and distributed computing. Currently, the 5.9 GHz Dedicated Short Range Communications (DSRC) and 4G-Long-Term Evolution (LTE) are available for connected vehicle services. But both have limitations in reliability or latency over large scale field operational tests and deployment. This paper proposes the device-to-device (D2D) connectivity framework based on publish-subscribe architecture, with Message Queue Telemetry Transport (MQTT) protocol. With the publish-subscribe communication paradigm, road mobile users can exchange data and information in moderate latency and high reliability manner, having the potential to support many Vehicle to Everything (V2X) applications, including vehicle to vehicle (V2V), vehicle to roadside infrastructure (V2I), and vehicle to bicycle (V2B). The D2D data exchanges also facilitate computing for absolute and relative precise real-time kinematic (RTK) posi-tioning. Vehicular experiments were conducted to evaluate the performance of the proposed publish-subscribe MQTT protocols in term of latency and reliability. The latency of data exchanges is measured by One-trip-time (OTT) and the reliability is measured by the packet loss rate (PLR). Our results show that the latency of GNSS raw data exchanges between vehicles through 4G cellular networks at the rate of 10 Hz and the data rates of 10 kbps are less than 300 ms while the reliability is over 96%. Vehicular positioning experiments have also shown that vehicles can exchange raw GNSS data and complete mov-ing-base RTK positioning with the positioning availability of 98%.
文摘Machinery of China is an export-oriented authoritative magazine of the Ministry of Machinebuilding Industry, read by tens of thousands of directors and managers of electrical and machinery enterprises in China. It is published at home and abroad. It offers introductions to national and ministry policies and regulations concernmg the industry,provides authoritative industry statistics and accurately forecasts market trends for electrical and machinery products. In addition,
文摘Journal of Rock Mechanics and Geotechnical Engineering（JRMGE）is a new academic publication in English launched in 2009,co-sponsored by Institute of Rock and Soil Mechanics,China Academy of Sciences,Chinese Society for Rock Mechanics and Engineering and Wuhan University.
文摘Rural revitalization was a major focus during this year’s“two sessions.”THE drive to advance China’s all-around rural revitalization comprises advances in agriculture,revitalization of rural areas,and well-being of rural residents–the“three rural work,”as emphasized by Premier Li Qiang in the 2025 government work report.
