The existing active queue management （AQM） algorithm acts on subscribers and edge routers only, it does not support differentiate-serve （Diffserv） quality of service （QoS）, while the existing diffserv QoS has no...The existing active queue management （AQM） algorithm acts on subscribers and edge routers only, it does not support differentiate-serve （Diffserv） quality of service （QoS）, while the existing diffserv QoS has not considered the link capacities between edge routers and connected core routers. When a core router in a two layers’ network experiences congestion, the connected edge routers have no ability to adjust their access data rates. Thus, it is difficult to achieve the congestion control for the large scale network with many edge routers and core routers. To solve these problems, two difffserve AQM algorithms are proposed for the congestion control of multilayer network. One diffserv AQM algorithm implements fair link capacities of edge routers, and the other one implements unequal link capacities of edge routers, but it requires the core routers to have multi-queues buffers and Diffserv AQM to support. The proposed algorithms achieve the network congestion control by operating AQM parameters on the conditions of proposed three theorems for core and edge routers. The dynamic simulation results demonstrate the proposed control algorithms for core and edge routers to be valid.展开更多
A Single-Buffered （SB） router is a router where only one stage of shared buffering is sandwiched between two interconnects in comparison of a Combined Input and Output Queued （CIOQ） router where a central switch f...A Single-Buffered （SB） router is a router where only one stage of shared buffering is sandwiched between two interconnects in comparison of a Combined Input and Output Queued （CIOQ） router where a central switch fabric is sandwiched between two stages of buffering. The notion of SB routers was firstly proposed by the High-Performance Networking Group （HPNG） of Stanford University, along with two promising designs of SB routers： one of which was Parallel Shared Memory （PSM） router and the other was Distributed Shared Memory （DSM） router. Admittedly, the work of HPNG deserved full credit, but all results presented by them appeared to relay on a Centralized Memory Management Algorithm （CMMA） which was essentially impractical because of the high processing and communication complexity. This paper attempts to make a scalable high-speed SB router completely practical by introducing a fully distributed architecture for managing the shared memory of SB routers. The resulting SB router is called as a Virtual Output and Input Queued （VOIQ） router. Furthermore, the scheme of VOIQ routers can not only eliminate the need for the CMMA scheduler, thus allowing a fully distributed implementation with low processing and commu- nication complexity, but also provide QoS guarantees and efficiently support variable-length packets in this paper. In particular, the results of performance testing and the hardware implementation of our VOIQ-based router （NDSC~ SR1880-TTM series） are illustrated at the end of this paper. The proposal of this paper is the first distributed scheme of how to design and implement SB routers publicized till now.展开更多
Compared with the traditional and inter-chip networks, on-chip networks （NoCs） have enormous wire resources which can be traded for improving other performance requirements. This means that much wider data links can...Compared with the traditional and inter-chip networks, on-chip networks （NoCs） have enormous wire resources which can be traded for improving other performance requirements. This means that much wider data links can be used for NoCs. This paper focuses on the area costs for on-chip routers under four different data-link widths： 8 bits, 16 bits, 128 bits, and 256bits. Firstly, a virtual-channel based on-chip router is introduced. Secondly, the components of the router are implemented by Verilog HDL models and synthesized by Quartus II 4.0 in a FPGA device. Finally, the area costs are analyzed. It can be seen from the results that data-link width has great influence on area costs of buffers and crossbar while has no influence on area costs of arbiter.展开更多
Multiport magnetic network energy routers(MNERs)are a key technology in the energy internet that can improve the consumption level of renewable energy,realize the integration of source-grid-load-storage,and ensure the...Multiport magnetic network energy routers(MNERs)are a key technology in the energy internet that can improve the consumption level of renewable energy,realize the integration of source-grid-load-storage,and ensure the stable operation of power systems.However,the power grid may break down,causing the grid currents to exceed the safe threshold and the DC bus voltages to fluctuate,thereby threatening the stability of the power system.A coordinated low-voltage ride-through(LVRT)control strategy for an MNER-based grid connection system is proposed.The proposed control strategy can provide significant LVRT capability for an MNER-based grid-connection system and maintain the DC bus voltage of each port at the rated value.A simulation is conducted using the PLECS platform,and the results validate the effectiveness of the proposed coordinated LVRT control strategy.展开更多
In context of the emerging energy internet,the energy router(ER)is one of the core components of multiport energy conversion and active energy flow regulation.In this paper,ER is classified into three categories based...In context of the emerging energy internet,the energy router(ER)is one of the core components of multiport energy conversion and active energy flow regulation.In this paper,ER is classified into three categories based on its functional characteristics:electrical ER,information ER,and multi-energy ER.Based on the differences between the categories,this paper divides the research on ER into four aspects:power conversion,which focuses on multi-port power conversion;energy routing,which is concerned with the optimization of power flow between ports;information processing and optimal control,which is characterized by an emphasis on intelligence,the coupling of information and energy flow;multi-energy,which has the comprehensive utilization of multiple energies as its main objective.Building on these four research aspects,this paper explores the topologies,control strategies,and optimization methods of ER and related techniques.It compensates for the limitation in coverage due to existing research focusing only on specific application scenarios.This paper also explores the potential of ER to promote the economic and stable operation of power grids.Finally,an outlook is provided on the prospective roles and applications of ER in next-generation energy systems.展开更多
A Prioritized Medium Access Control （P-MAC） protocol is proposed for wireless routers of mesh networks with quality-of-service provisioning. The simple yet effective design of P-MAC offers strict service differentia...A Prioritized Medium Access Control （P-MAC） protocol is proposed for wireless routers of mesh networks with quality-of-service provisioning. The simple yet effective design of P-MAC offers strict service differentiation for prioritized packets. A Markov model is developed to yield important performance matrices including the packet blocking probability due to queue overflow and the packet reneging probability due to delay bound. It is further proved that the service time of P-MAC approximates exponential distribution, and can be effectively estimated. The analytic models with preemptive and non-preemptive schemes, validated via simulations, show that P-MAC can effectively support traffic differentiation and achieve very low packet dropping （both reneging and blocking） probabilities when the traffic load is below the channel capacity. When the network is overloaded, P-MAC can still maintain extremely stable and high channel throughput. Moreover, it is demonstrated that P-MAC performs superior in multihop networks, further proving the advantages of the proposed protocol.展开更多
Virtual routers are gaining increasing attention in the research field of future networks. As the core network device to achieve network virtualization, virtual routers have multiple virtual instances coexisting on a ...Virtual routers are gaining increasing attention in the research field of future networks. As the core network device to achieve network virtualization, virtual routers have multiple virtual instances coexisting on a physical router platform, and each instance retains its own forwarding information base （FIB）. Thus, memory scalability suffers from the limited on-chip memory. In this paper, we present a splitting-after-merging approach to compress the FIBs, which not only improves the memory efficiency but also offers an ideal split position to achieve system refactoring. Moreover, we propose an improved strategy to save the time used for system rebuilding to achieve fast refactoring. Experiments with 14 real-world routing data sets show that our approach needs only a unibit trie holding 134 188 nodes, while the original number of nodes is 4 569 133. Moreover, our approach has a good performance in scalability, guaranteeing 90 000 000 prefixes and 65 600 FIBs.展开更多
In the feld of information processing,all-optical routers are signifcant for achieving high-speed,high-capacity signal processing and transmission.In this study,we developed three types of structurally simple and fexi...In the feld of information processing,all-optical routers are signifcant for achieving high-speed,high-capacity signal processing and transmission.In this study,we developed three types of structurally simple and fexible routers using the deep difractive neural network(D2 NN),capable of routing incident light based on wavelength and polarization.First,we implemented a polarization router for routing two orthogonally polarized light beams.The second type is the wavelength router that can route light with wavelengths of 1550,1300,and 1100 nm,demonstrating outstanding performance with insertion loss as low as 0.013 dB and an extinction ratio of up to 18.96 dB,while also maintaining excellent polarization preservation.The fnal router is the polarization-wavelength composite router,capable of routing six types of input light formed by pairwise combinations of three wavelengths(1550,1300,and 1100 nm)and two orthogonal linearly polarized lights,thereby enhancing the information processing capability of the device.These devices feature compact structures,maintaining high contrast while exhibiting low loss and passive characteristics,making them suitable for integration into future optical components.This study introduces new avenues and methodologies to enhance performance and broaden the applications of future optical information processing systems.展开更多
A high proportion of renewable energy affects the power quality of distribution networks,and surplus energy will be sold to the upstream grid at a low price.In this paper,considering peer-to-peer energy transactions,t...A high proportion of renewable energy affects the power quality of distribution networks,and surplus energy will be sold to the upstream grid at a low price.In this paper,considering peer-to-peer energy transactions,the energy router-based multiple distribution networks are analyzed to solve the above problems and realize collaborative consumption of renewable energy.Presently,the investing cost of an energy router is high,and research on the economic operation of energy routers in distribution networks is little.Therefore,this paper establishes a planning model for energy routers considering peer-to-peer energy transactions among distribution networks,and explores the benefits of peer-to-peer energy transactions through energy router based multiple distribution networks.A structure of an energy router suitable for peer-to-peer energy transactions is selected,and a power flow calculation model based on a multilayer structure is established.The energy router’s scheduling model is established,and unique functions of the energy router and revenue of each distribution network are considered.A power flow calculation model based on peer-to-peer interconnection of multiple distribution networks through energy routers is also established.Finally,simulation results verify the effectiveness of the proposed planning model.Results show that peer-topeer energy transaction among distribution networks through energy routers can effectively reduce the comprehensive cost of distribution networks,significantly improve the power quality of the distribution networks,and reduce the impact of power fluctuation on the upstream grid incurred by the distribution network.展开更多
Railway power system is an inseparable part of the power system,therefore,the intelligent architecture of the railway power system should also be focused on.The unique power supply characteristics of the railway power...Railway power system is an inseparable part of the power system,therefore,the intelligent architecture of the railway power system should also be focused on.The unique power supply characteristics of the railway power system are analyzed and integrated railway smart grid architecture based on energy routers is proposed.Importantly,three corresponding resilient mode control methods are suggested for the proposed architecture.In the fourth section,a simulation model corresponding to the resilient control mode is built and the simulation results prove the feasibility of the proposed control mode.Equally,for the novel network-connected backbone router(NCBR),a 1000 kVA,27.5/10 kV NCBR engineering prototype is used to prove its effectiveness in practical applications.Finally,a differentiation analysis is given,followed by conclusions regarding the traditional power system and proposed system.展开更多
The exponential growth of user traffic has been driving routers to run at higher capacity. In a traditional router, the centralized switching fabric is becoming the bottleneck for its limited number of ports and compl...The exponential growth of user traffic has been driving routers to run at higher capacity. In a traditional router, the centralized switching fabric is becoming the bottleneck for its limited number of ports and complicated scheduling algorithms. Direct networks, such as 3-D Torus topology, have been successfully applied to the design of scalable routers. They show good scalability and fault tolerance. Unfortunately, its scalability is limited in practice. In this paper, we introduce another type of direct network, called H-Torus. This network shows excellent topological properties. On its basis, the designs of line card and routing algorithms are introduced. Extensive simulations show that the routing algorithm is very important in such a system and results in low latency with high throughput.展开更多
Optical network-on-chip(ONoC) systems have emerged as a promising solution to overcome limitations of traditional electronic interconnects. Efficient ONoC architectures rely on optical routers, enabling high-speed dat...Optical network-on-chip(ONoC) systems have emerged as a promising solution to overcome limitations of traditional electronic interconnects. Efficient ONoC architectures rely on optical routers, enabling high-speed data transfer, efficient routing, and scalability. This paper presents a comprehensive survey analyzing optical router designs, specifically microring resonators(MRRs), Mach-Zehnder interferometers(MZIs), and hybrid architectures. Selected comparison criteria, chosen for their critical importance, significantly impact router functionality and performance. By emphasizing these criteria, valuable insights into the strengths and limitations of different designs are gained, facilitating informed decisions and advancements in optical networking. While other factors contribute to performance and efficiency, the chosen criteria consistently address fundamental elements, enabling meaningful evaluation. This work serves as a valuable resource for beginners, providing a solid foundation in understanding ONoC and optical routers. It also offers an in-depth survey for experts, laying the groundwork for further exploration. Additionally, the importance of considering design constraints and requirements when selecting an optimal router design is highlighted. Continued research and innovation will enable the development of efficient optical router solutions that meet the evolving needs of modern computing systems. This survey underscores the significance of ongoing advancements in the field and their potential impact on future technologies.展开更多
The proliferation of heterogeneous networks,such as the Internet of Things(IoT),unmanned aerial vehicle(UAV)networks,and edge networks,has increased the complexity of network operation and administration,driving the e...The proliferation of heterogeneous networks,such as the Internet of Things(IoT),unmanned aerial vehicle(UAV)networks,and edge networks,has increased the complexity of network operation and administration,driving the emergence of digital twin networks(DTNs)that create digital-physical network mappings.While DTNs enable performance analysis through emulation testbeds,current research focuses on network-level systems,neglecting equipment-level emulation of critical components like core switches and routers.To address this issue,we propose v Fabric(short for virtual switch),a digital twin emulator for high-capacity core switching equipment.This solution implements virtual switching and network processor(NP)chip models through specialized processes,deployable on single or distributed servers via socket communication.The v Fabric emulator can realize the accurate emulation for the core switching equipment with 720 ports and 100 Gbit/s per port on the largest scale.To our knowledge,this represents the first digital twin emulation framework specifically designed for large-capacity core switching equipment in communication networks.展开更多
Named data networking(NDNs)is an idealized deployment of information-centric networking(ICN)that has attracted attention from scientists and scholars worldwide.A distributed in-network caching scheme can efficiently r...Named data networking(NDNs)is an idealized deployment of information-centric networking(ICN)that has attracted attention from scientists and scholars worldwide.A distributed in-network caching scheme can efficiently realize load balancing.However,such a ubiquitous caching approach may cause problems including duplicate caching and low data diversity,thus reducing the caching efficiency of NDN routers.To mitigate these caching problems and improve the NDN caching efficiency,in this paper,a hierarchical-based sequential caching(HSC)scheme is proposed.In this scheme,the NDN routers in the data transmission path are divided into various levels and data with different request frequencies are cached in distinct router levels.The aim is to cache data with high request frequencies in the router that is closest to the content requester to increase the response probability of the nearby data,improve the data caching efficiency of named data networks,shorten the response time,and reduce cache redundancy.Simulation results show that this scheme can effectively improve the cache hit rate(CHR)and reduce the average request delay(ARD)and average route hop(ARH).展开更多
The economic dispatch problem(EDP) of microgrids operating in both grid-connected and isolated modes within an energy internet framework is addressed in this paper. The multi-agent leader-following consensus algorithm...The economic dispatch problem(EDP) of microgrids operating in both grid-connected and isolated modes within an energy internet framework is addressed in this paper. The multi-agent leader-following consensus algorithm is employed to address the EDP of microgrids in grid-connected mode, while the push-pull algorithm with a fixed step size is introduced for the isolated mode. The proposed algorithm of isolated mode is proven to converge to the optimum when the interaction digraph of microgrids is strongly connected. A unified algorithmic framework is proposed to handle the two modes of operation of microgrids simultaneously, enabling our algorithm to achieve optimal power allocation and maintain the balance between power supply and demand in any mode and any mode switching. Due to the push-pull structure of the algorithm and the use of fixed step size,the proposed algorithm can better handle the case of unbalanced graphs, and the convergence speed is improved. It is documented that when the transmission topology is strongly connected and there is bi-directional communication between the energy router and its neighbors, the proposed algorithm in composite mode achieves economic dispatch even with arbitrary mode switching.Finally, we demonstrate the effectiveness and superiority of our algorithm through numerical simulations.展开更多
The medium access control (MAC) issue was discussed in mobile Ad Hoc networks (MANETs). Based on the IEEE 802.11 MAC protocol, this paper proposed two schemes, the forward-packet-first (FPF) scheme based on the adapti...The medium access control (MAC) issue was discussed in mobile Ad Hoc networks (MANETs). Based on the IEEE 802.11 MAC protocol, this paper proposed two schemes, the forward-packet-first (FPF) scheme based on the adaptive backoff contention window and multihop forward chain transmission by invitation (MFCTI) scheme. In the FPF scheme, the contention window was adjusted adaptively according to the traffic priority. Route information and the broadcast characteristic of radio were utilized in MFCTI scheme. The performance of these schemes was studied in multihop environments by simulations. The results showed that the proposed schemes could improve the network throughput, reduce the end-to-end average delay, and mitigate local congestion effectively. Another attractive feature was that the schemes could be implemented with minor modifications to the IEEE 802.11 MAC.展开更多
基金supported by the Beijing Natural Science Foundation (4102050)NSFC-KOSEF Joint Research Project of China and Korea(60811140343), and the CDSN, GIST.
文摘The existing active queue management （AQM） algorithm acts on subscribers and edge routers only, it does not support differentiate-serve （Diffserv） quality of service （QoS）, while the existing diffserv QoS has not considered the link capacities between edge routers and connected core routers. When a core router in a two layers’ network experiences congestion, the connected edge routers have no ability to adjust their access data rates. Thus, it is difficult to achieve the congestion control for the large scale network with many edge routers and core routers. To solve these problems, two difffserve AQM algorithms are proposed for the congestion control of multilayer network. One diffserv AQM algorithm implements fair link capacities of edge routers, and the other one implements unequal link capacities of edge routers, but it requires the core routers to have multi-queues buffers and Diffserv AQM to support. The proposed algorithms achieve the network congestion control by operating AQM parameters on the conditions of proposed three theorems for core and edge routers. The dynamic simulation results demonstrate the proposed control algorithms for core and edge routers to be valid.
基金the National High-Tech Research and De-velopment Program of China (863 Program) (2003AA103510, 2004AA103130, 2005AA121210).
文摘A Single-Buffered （SB） router is a router where only one stage of shared buffering is sandwiched between two interconnects in comparison of a Combined Input and Output Queued （CIOQ） router where a central switch fabric is sandwiched between two stages of buffering. The notion of SB routers was firstly proposed by the High-Performance Networking Group （HPNG） of Stanford University, along with two promising designs of SB routers： one of which was Parallel Shared Memory （PSM） router and the other was Distributed Shared Memory （DSM） router. Admittedly, the work of HPNG deserved full credit, but all results presented by them appeared to relay on a Centralized Memory Management Algorithm （CMMA） which was essentially impractical because of the high processing and communication complexity. This paper attempts to make a scalable high-speed SB router completely practical by introducing a fully distributed architecture for managing the shared memory of SB routers. The resulting SB router is called as a Virtual Output and Input Queued （VOIQ） router. Furthermore, the scheme of VOIQ routers can not only eliminate the need for the CMMA scheduler, thus allowing a fully distributed implementation with low processing and commu- nication complexity, but also provide QoS guarantees and efficiently support variable-length packets in this paper. In particular, the results of performance testing and the hardware implementation of our VOIQ-based router （NDSC~ SR1880-TTM series） are illustrated at the end of this paper. The proposal of this paper is the first distributed scheme of how to design and implement SB routers publicized till now.
文摘Compared with the traditional and inter-chip networks, on-chip networks （NoCs） have enormous wire resources which can be traded for improving other performance requirements. This means that much wider data links can be used for NoCs. This paper focuses on the area costs for on-chip routers under four different data-link widths： 8 bits, 16 bits, 128 bits, and 256bits. Firstly, a virtual-channel based on-chip router is introduced. Secondly, the components of the router are implemented by Verilog HDL models and synthesized by Quartus II 4.0 in a FPGA device. Finally, the area costs are analyzed. It can be seen from the results that data-link width has great influence on area costs of buffers and crossbar while has no influence on area costs of arbiter.
基金Supported by the National Key Research and Development Program of China(2022YFE0196300)Science,Technology&Innovation Funding Authority(STDF)(46505).
文摘Multiport magnetic network energy routers(MNERs)are a key technology in the energy internet that can improve the consumption level of renewable energy,realize the integration of source-grid-load-storage,and ensure the stable operation of power systems.However,the power grid may break down,causing the grid currents to exceed the safe threshold and the DC bus voltages to fluctuate,thereby threatening the stability of the power system.A coordinated low-voltage ride-through(LVRT)control strategy for an MNER-based grid connection system is proposed.The proposed control strategy can provide significant LVRT capability for an MNER-based grid-connection system and maintain the DC bus voltage of each port at the rated value.A simulation is conducted using the PLECS platform,and the results validate the effectiveness of the proposed coordinated LVRT control strategy.
基金supported by Key Project of National Natural Science Foundation of China under Grant 62433013.
文摘In context of the emerging energy internet,the energy router(ER)is one of the core components of multiport energy conversion and active energy flow regulation.In this paper,ER is classified into three categories based on its functional characteristics:electrical ER,information ER,and multi-energy ER.Based on the differences between the categories,this paper divides the research on ER into four aspects:power conversion,which focuses on multi-port power conversion;energy routing,which is concerned with the optimization of power flow between ports;information processing and optimal control,which is characterized by an emphasis on intelligence,the coupling of information and energy flow;multi-energy,which has the comprehensive utilization of multiple energies as its main objective.Building on these four research aspects,this paper explores the topologies,control strategies,and optimization methods of ER and related techniques.It compensates for the limitation in coverage due to existing research focusing only on specific application scenarios.This paper also explores the potential of ER to promote the economic and stable operation of power grids.Finally,an outlook is provided on the prospective roles and applications of ER in next-generation energy systems.
基金Supported in part by the National Science Foundation CAREER Award (No. CNS-0347686)US Department of Energy (DoE) (No. DE-FG02-04ER46136)
文摘A Prioritized Medium Access Control （P-MAC） protocol is proposed for wireless routers of mesh networks with quality-of-service provisioning. The simple yet effective design of P-MAC offers strict service differentiation for prioritized packets. A Markov model is developed to yield important performance matrices including the packet blocking probability due to queue overflow and the packet reneging probability due to delay bound. It is further proved that the service time of P-MAC approximates exponential distribution, and can be effectively estimated. The analytic models with preemptive and non-preemptive schemes, validated via simulations, show that P-MAC can effectively support traffic differentiation and achieve very low packet dropping （both reneging and blocking） probabilities when the traffic load is below the channel capacity. When the network is overloaded, P-MAC can still maintain extremely stable and high channel throughput. Moreover, it is demonstrated that P-MAC performs superior in multihop networks, further proving the advantages of the proposed protocol.
基金Project supported by the National Basic Research Program （973） of China （No. 2012CB315805）, the National Natural Science Foundation of China （Nos. 61173167 and 61472130）, the Prospective Research Project on Future Networks of Jiangsu Future Networks Innovation Institute, China （No. 2013095-1-05）, the Hunan Provincial Innovation Foundation for Postgraduate, China （No. CX2014B150）, and the State Scholarship Fund of China （No. 201406130048）
文摘Virtual routers are gaining increasing attention in the research field of future networks. As the core network device to achieve network virtualization, virtual routers have multiple virtual instances coexisting on a physical router platform, and each instance retains its own forwarding information base （FIB）. Thus, memory scalability suffers from the limited on-chip memory. In this paper, we present a splitting-after-merging approach to compress the FIBs, which not only improves the memory efficiency but also offers an ideal split position to achieve system refactoring. Moreover, we propose an improved strategy to save the time used for system rebuilding to achieve fast refactoring. Experiments with 14 real-world routing data sets show that our approach needs only a unibit trie holding 134 188 nodes, while the original number of nodes is 4 569 133. Moreover, our approach has a good performance in scalability, guaranteeing 90 000 000 prefixes and 65 600 FIBs.
基金supported by the National Natural Science Foundation of China(Grant Nos.11734001,11704017,91950204,92150302,12274478,and 61775244)the National Key Research and Development Program of China(Nos.2018YFB2200403,2021YFB2800604,and 2021YFB2800302)the Natural Science Foundation of Beijing Municipality(No.Z180015).
文摘In the feld of information processing,all-optical routers are signifcant for achieving high-speed,high-capacity signal processing and transmission.In this study,we developed three types of structurally simple and fexible routers using the deep difractive neural network(D2 NN),capable of routing incident light based on wavelength and polarization.First,we implemented a polarization router for routing two orthogonally polarized light beams.The second type is the wavelength router that can route light with wavelengths of 1550,1300,and 1100 nm,demonstrating outstanding performance with insertion loss as low as 0.013 dB and an extinction ratio of up to 18.96 dB,while also maintaining excellent polarization preservation.The fnal router is the polarization-wavelength composite router,capable of routing six types of input light formed by pairwise combinations of three wavelengths(1550,1300,and 1100 nm)and two orthogonal linearly polarized lights,thereby enhancing the information processing capability of the device.These devices feature compact structures,maintaining high contrast while exhibiting low loss and passive characteristics,making them suitable for integration into future optical components.This study introduces new avenues and methodologies to enhance performance and broaden the applications of future optical information processing systems.
基金supported in part by the Fundamental Research Funds for the Central Universities under Grant 2018JBZ004.
文摘A high proportion of renewable energy affects the power quality of distribution networks,and surplus energy will be sold to the upstream grid at a low price.In this paper,considering peer-to-peer energy transactions,the energy router-based multiple distribution networks are analyzed to solve the above problems and realize collaborative consumption of renewable energy.Presently,the investing cost of an energy router is high,and research on the economic operation of energy routers in distribution networks is little.Therefore,this paper establishes a planning model for energy routers considering peer-to-peer energy transactions among distribution networks,and explores the benefits of peer-to-peer energy transactions through energy router based multiple distribution networks.A structure of an energy router suitable for peer-to-peer energy transactions is selected,and a power flow calculation model based on a multilayer structure is established.The energy router’s scheduling model is established,and unique functions of the energy router and revenue of each distribution network are considered.A power flow calculation model based on peer-to-peer interconnection of multiple distribution networks through energy routers is also established.Finally,simulation results verify the effectiveness of the proposed planning model.Results show that peer-topeer energy transaction among distribution networks through energy routers can effectively reduce the comprehensive cost of distribution networks,significantly improve the power quality of the distribution networks,and reduce the impact of power fluctuation on the upstream grid incurred by the distribution network.
基金Supported by the Zhuhai City Industry-University-Research Project(ZH22017001200019PWC).
文摘Railway power system is an inseparable part of the power system,therefore,the intelligent architecture of the railway power system should also be focused on.The unique power supply characteristics of the railway power system are analyzed and integrated railway smart grid architecture based on energy routers is proposed.Importantly,three corresponding resilient mode control methods are suggested for the proposed architecture.In the fourth section,a simulation model corresponding to the resilient control mode is built and the simulation results prove the feasibility of the proposed control mode.Equally,for the novel network-connected backbone router(NCBR),a 1000 kVA,27.5/10 kV NCBR engineering prototype is used to prove its effectiveness in practical applications.Finally,a differentiation analysis is given,followed by conclusions regarding the traditional power system and proposed system.
基金the National Natural Science Foundation of China under Grant Nos,90604029 and 60773150the National Grand Fundamental Research 973 Program of China under Grant No.2003CB314801.
文摘The exponential growth of user traffic has been driving routers to run at higher capacity. In a traditional router, the centralized switching fabric is becoming the bottleneck for its limited number of ports and complicated scheduling algorithms. Direct networks, such as 3-D Torus topology, have been successfully applied to the design of scalable routers. They show good scalability and fault tolerance. Unfortunately, its scalability is limited in practice. In this paper, we introduce another type of direct network, called H-Torus. This network shows excellent topological properties. On its basis, the designs of line card and routing algorithms are introduced. Extensive simulations show that the routing algorithm is very important in such a system and results in low latency with high throughput.
文摘Optical network-on-chip(ONoC) systems have emerged as a promising solution to overcome limitations of traditional electronic interconnects. Efficient ONoC architectures rely on optical routers, enabling high-speed data transfer, efficient routing, and scalability. This paper presents a comprehensive survey analyzing optical router designs, specifically microring resonators(MRRs), Mach-Zehnder interferometers(MZIs), and hybrid architectures. Selected comparison criteria, chosen for their critical importance, significantly impact router functionality and performance. By emphasizing these criteria, valuable insights into the strengths and limitations of different designs are gained, facilitating informed decisions and advancements in optical networking. While other factors contribute to performance and efficiency, the chosen criteria consistently address fundamental elements, enabling meaningful evaluation. This work serves as a valuable resource for beginners, providing a solid foundation in understanding ONoC and optical routers. It also offers an in-depth survey for experts, laying the groundwork for further exploration. Additionally, the importance of considering design constraints and requirements when selecting an optimal router design is highlighted. Continued research and innovation will enable the development of efficient optical router solutions that meet the evolving needs of modern computing systems. This survey underscores the significance of ongoing advancements in the field and their potential impact on future technologies.
基金supported in part by the National Natural Science Foundation of China(NSFC)under Grant Nos.62171085,62272428,62001087,U20A20156,and 61871097the ZTE Industry-University-Institute Cooperation Funds under Grant No.HC-CN-20220722010。
文摘The proliferation of heterogeneous networks,such as the Internet of Things(IoT),unmanned aerial vehicle(UAV)networks,and edge networks,has increased the complexity of network operation and administration,driving the emergence of digital twin networks(DTNs)that create digital-physical network mappings.While DTNs enable performance analysis through emulation testbeds,current research focuses on network-level systems,neglecting equipment-level emulation of critical components like core switches and routers.To address this issue,we propose v Fabric(short for virtual switch),a digital twin emulator for high-capacity core switching equipment.This solution implements virtual switching and network processor(NP)chip models through specialized processes,deployable on single or distributed servers via socket communication.The v Fabric emulator can realize the accurate emulation for the core switching equipment with 720 ports and 100 Gbit/s per port on the largest scale.To our knowledge,this represents the first digital twin emulation framework specifically designed for large-capacity core switching equipment in communication networks.
基金supported in part by the National Natural Science Foundation of China under Grant 61972424 and 62372479in part by the High Value Intellectual Property Cultivation Project of Hubei Province,China,under grant D2021002094+1 种基金in part by JSPS KAKENHI under Grants JP16K00117 and JP19K20250in part by the Leading Initiative for Excellent Young Researchers(LEADER),MEXT,Japan,and KDDI Foundation.
文摘Named data networking(NDNs)is an idealized deployment of information-centric networking(ICN)that has attracted attention from scientists and scholars worldwide.A distributed in-network caching scheme can efficiently realize load balancing.However,such a ubiquitous caching approach may cause problems including duplicate caching and low data diversity,thus reducing the caching efficiency of NDN routers.To mitigate these caching problems and improve the NDN caching efficiency,in this paper,a hierarchical-based sequential caching(HSC)scheme is proposed.In this scheme,the NDN routers in the data transmission path are divided into various levels and data with different request frequencies are cached in distinct router levels.The aim is to cache data with high request frequencies in the router that is closest to the content requester to increase the response probability of the nearby data,improve the data caching efficiency of named data networks,shorten the response time,and reduce cache redundancy.Simulation results show that this scheme can effectively improve the cache hit rate(CHR)and reduce the average request delay(ARD)and average route hop(ARH).
基金supported by the National Natural Science Foundation of China(62103203)
文摘The economic dispatch problem(EDP) of microgrids operating in both grid-connected and isolated modes within an energy internet framework is addressed in this paper. The multi-agent leader-following consensus algorithm is employed to address the EDP of microgrids in grid-connected mode, while the push-pull algorithm with a fixed step size is introduced for the isolated mode. The proposed algorithm of isolated mode is proven to converge to the optimum when the interaction digraph of microgrids is strongly connected. A unified algorithmic framework is proposed to handle the two modes of operation of microgrids simultaneously, enabling our algorithm to achieve optimal power allocation and maintain the balance between power supply and demand in any mode and any mode switching. Due to the push-pull structure of the algorithm and the use of fixed step size,the proposed algorithm can better handle the case of unbalanced graphs, and the convergence speed is improved. It is documented that when the transmission topology is strongly connected and there is bi-directional communication between the energy router and its neighbors, the proposed algorithm in composite mode achieves economic dispatch even with arbitrary mode switching.Finally, we demonstrate the effectiveness and superiority of our algorithm through numerical simulations.
文摘The medium access control (MAC) issue was discussed in mobile Ad Hoc networks (MANETs). Based on the IEEE 802.11 MAC protocol, this paper proposed two schemes, the forward-packet-first (FPF) scheme based on the adaptive backoff contention window and multihop forward chain transmission by invitation (MFCTI) scheme. In the FPF scheme, the contention window was adjusted adaptively according to the traffic priority. Route information and the broadcast characteristic of radio were utilized in MFCTI scheme. The performance of these schemes was studied in multihop environments by simulations. The results showed that the proposed schemes could improve the network throughput, reduce the end-to-end average delay, and mitigate local congestion effectively. Another attractive feature was that the schemes could be implemented with minor modifications to the IEEE 802.11 MAC.
