Software-defined networking(SDN),a new networking paradigm decoupling the software control logic from the data forwarding hardware,promises to enable simpler management,more flexible resource usage and faster deployme...Software-defined networking(SDN),a new networking paradigm decoupling the software control logic from the data forwarding hardware,promises to enable simpler management,more flexible resource usage and faster deployment of network services.It opens network functionality,application programmability,and control-to-data communication interfaces that used to be closed in conventional network devices,offering endless opportunities but also challenges for both existing players and newcomers in the market.Through a comprehensive and comparative exploratory of SDN state-of-theart techniques,standardization activities and realistic applications,this article unveils historic and technical insights into the innovations that SDN offers toward an emerging open network eco-system.We closely examine the critical challenges and opportunities when the networking industry is reshaped by SDN.We further shed light on future development directions of SDN in broad application scenarios,ranging from cloud datacenters,network operating systems,and advanced wireless networking.展开更多
The integration of distributed generation brings in new challenges for the operation of distribution networks,including out-of-limit voltage and power flow control.Soft open points(SOP)are new power electronic devices...The integration of distributed generation brings in new challenges for the operation of distribution networks,including out-of-limit voltage and power flow control.Soft open points(SOP)are new power electronic devices that can flexibly control active and reactive power flows.With the exception of active power output,photovoltaic(PV)devices can provide reactive power compensation through an inverter.Thus,a synergetic optimization operation method for SOP and PV in a distribution network is proposed.A synergetic optimization model was developed.The voltage deviation,network loss,and ratio of photovoltaic abandonment were selected as the objective functions.The PV model was improved by considering the three reactive power output modes of the PV inverter.Both the load fluctuation and loss of the SOP were considered.Three multi-objective optimization algorithms were used,and a compromise optimal solution was calculated.Case studies were conducted using an IEEE 33-node system.The simulation results indicated that the SOP and PVs complemented each other in terms of active power transmission and reactive power compensation.Synergetic optimization improves power control capability and flexibility,providing better power quality and PV consumption rate.展开更多
There are an increasing of scenarios that require the independent bandwidth and delay demands. For instance, in a data center, the interactive message would not occupy much bandwidth, but it requires the rigorous dema...There are an increasing of scenarios that require the independent bandwidth and delay demands. For instance, in a data center, the interactive message would not occupy much bandwidth, but it requires the rigorous demands for the delay. However, the existing QoS approaches are mainly bandwidth based, which are inappropriate for these scenarios. Hence, we propose the decoupled scheme in the OpenFlow networks to provide the centralized differential bandwidth and delay control. We leverage the mature HTB to manage the bandwidth. And we design the Queue Delay Management Scheme (QDMS) for queuing delay arrangement, as well as the Comprehensive Parameters based Dijkstra Route algorithm (CPDR) for the propagation delay control. The evaluation results verify the decoupling effectiveness. And the decoupled scheme can reduce the delay for high priority flows.展开更多
In this paper, the open queueing network model is proposed for solving the problem of public transportation in cities. The vertices of the networks(i.e., the bus stops) are determined by means of the fuzzy clusteri...In this paper, the open queueing network model is proposed for solving the problem of public transportation in cities. The vertices of the networks(i.e., the bus stops) are determined by means of the fuzzy clustering method. The arcs (i.e., the paths of the public transportation) can be set up by using the shortest path model in the time sense or the 0 1 integer programming method.Applying the statistics method, we can calculate the parameters(such as the passenger flow's distribution, passenger flow's transition probability, mean waiting time for the bus etc. ) of the public transportation network. In this paper, we suggest to divide the network into two or three stages to implement the public transportation system in the form of ``frog jumping' fast transfer and ``permeation' fast dispersion.Combining the computer simulation and the evaluation of the achievement and effect of public transportation system, we modify the model so as to solve the public transportation problem better.展开更多
To improve the recognition ability of communication jamming signals,Siamese Neural Network-based Open World Recognition(SNNOWR)is proposed.The algorithm can recognize known jamming classes,detect new(unknown)jamming c...To improve the recognition ability of communication jamming signals,Siamese Neural Network-based Open World Recognition(SNNOWR)is proposed.The algorithm can recognize known jamming classes,detect new(unknown)jamming classes,and unsupervised cluseter new classes.The network of SNN-OWR is trained supervised with paired input data consisting of two samples from a known dataset.On the one hand,the network is required to have the ability to distinguish whether two samples are from the same class.On the other hand,the latent distribution of known class is forced to approach their own unique Gaussian distribution,which is prepared for the subsequent open set testing.During the test,the unknown class detection process based on Gaussian probability density function threshold is designed,and an unsupervised clustering algorithm of the unknown jamming is realized by using the prior knowledge of known classes.The simulation results show that when the jamming-to-noise ratio is more than 0d B,the accuracy of SNN-OWR algorithm for known jamming classes recognition,unknown jamming detection and unsupervised clustering of unknown jamming is about 95%.This indicates that the SNN-OWR algorithm can make the effect of the recognition of unknown jamming be almost the same as that of known jamming.展开更多
After suffering from a grid blackout, distributed energy resources(DERs), such as local renewable energy and controllable distributed generators and energy storage can be used to restore loads enhancing the system’s ...After suffering from a grid blackout, distributed energy resources(DERs), such as local renewable energy and controllable distributed generators and energy storage can be used to restore loads enhancing the system’s resilience. In this study, a multi-source coordinated load restoration strategy was investigated for a distribution network with soft open points(SOPs). Here, the flexible regulation ability of the SOPs is fully utilized to improve the load restoration level while mitigating voltage deviations. Owing to the uncertainty, a scenario-based stochastic optimization approach was employed,and the load restoration problem was formulated as a mixed-integer nonlinear programming model. A computationally efficient solution algorithm was developed for the model using convex relaxation and linearization methods. The algorithm is organized into a two-stage structure, in which the energy storage system is dispatched in the first stage by solving a relaxed convex problem. In the second stage, an integer programming problem is calculated to acquire the outputs of both SOPs and power resources. A numerical test was conducted on both IEEE 33-bus and IEEE 123-bus systems to validate the effectiveness of the proposed strategy.展开更多
Due to 5G's stringent and uncertainty traffic requirements,open ecosystem would be one inevitable way to develop 5G.On the other hand,GPP based mobile communication becomes appealing recently attributed to its str...Due to 5G's stringent and uncertainty traffic requirements,open ecosystem would be one inevitable way to develop 5G.On the other hand,GPP based mobile communication becomes appealing recently attributed to its striking advantage in flexibility and re-configurability.In this paper,both the advantages and challenges of GPP platform are detailed analyzed.Furthermore,both GPP based software and hardware architectures for open 5G are presented and the performances of real-time signal processing and power consumption are also evaluated.The evaluation results indicate that turbo and power consumption may be another challengeable problem should be further solved to meet the requirements of realistic deployments.展开更多
The lack of current network dynamics studies that evaluate the effects of new application and protocol deployment or long-term studies that observe the effect of incremental changes on the Internet, and the change in ...The lack of current network dynamics studies that evaluate the effects of new application and protocol deployment or long-term studies that observe the effect of incremental changes on the Internet, and the change in the overall stability of the Internet under various conditions and threats has made network monitoring challenging. A good understanding of the nature and type of network traffic is the key to solving congestion problems. In this paper we describe the architecture and implementation of a scalable network traffic moni-toring and analysis system. The gigabit interface on the monitoring system was configured to capture network traffic and the Multi Router Traffic Grapher (MRTG) and Webalizer produces graphical and detailed traffic analysis. This system is in use at the Obafemi Awolowo University, IleIfe, Nigeria;we describe how this system can be replicated in another environment.展开更多
"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some pap..."Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/展开更多
"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some pap..."Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/展开更多
"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some pap..."Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chirtese and English abstract, which can be downloaded after registration.展开更多
"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some pap..."Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/展开更多
"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some pap..."Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access;展开更多
"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some pap..."Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/展开更多
"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some pap..."Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration.展开更多
"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some pap..."Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can he downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/展开更多
"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some pap..."Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/展开更多
"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some pap..."Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/展开更多
Geoscience Periodical Network of China a"is s composed of 233 Chinese geological journals,which covers all kinds of geological research fi(elds of China.All papers of this site comprise English abstract,and some ...Geoscience Periodical Network of China a"is s composed of 233 Chinese geological journals,which covers all kinds of geological research fi(elds of China.All papers of this site comprise English abstract,and some papers have figures with English description.Papers present as the展开更多
基金supported in part by agrant from the National Natural Science Foundation of China(NSFC)(Grant Nos.61370232 and 61520106005)
文摘Software-defined networking(SDN),a new networking paradigm decoupling the software control logic from the data forwarding hardware,promises to enable simpler management,more flexible resource usage and faster deployment of network services.It opens network functionality,application programmability,and control-to-data communication interfaces that used to be closed in conventional network devices,offering endless opportunities but also challenges for both existing players and newcomers in the market.Through a comprehensive and comparative exploratory of SDN state-of-theart techniques,standardization activities and realistic applications,this article unveils historic and technical insights into the innovations that SDN offers toward an emerging open network eco-system.We closely examine the critical challenges and opportunities when the networking industry is reshaped by SDN.We further shed light on future development directions of SDN in broad application scenarios,ranging from cloud datacenters,network operating systems,and advanced wireless networking.
基金supported by the Science and Technology Project of SGCC(kj2022-075).
文摘The integration of distributed generation brings in new challenges for the operation of distribution networks,including out-of-limit voltage and power flow control.Soft open points(SOP)are new power electronic devices that can flexibly control active and reactive power flows.With the exception of active power output,photovoltaic(PV)devices can provide reactive power compensation through an inverter.Thus,a synergetic optimization operation method for SOP and PV in a distribution network is proposed.A synergetic optimization model was developed.The voltage deviation,network loss,and ratio of photovoltaic abandonment were selected as the objective functions.The PV model was improved by considering the three reactive power output modes of the PV inverter.Both the load fluctuation and loss of the SOP were considered.Three multi-objective optimization algorithms were used,and a compromise optimal solution was calculated.Case studies were conducted using an IEEE 33-node system.The simulation results indicated that the SOP and PVs complemented each other in terms of active power transmission and reactive power compensation.Synergetic optimization improves power control capability and flexibility,providing better power quality and PV consumption rate.
基金supported National Natural Science Foundation of China (Project Number: 61671086)Consulting Project of Chinese Academy of Engineering (Project Number: 2016-XY-09)
文摘There are an increasing of scenarios that require the independent bandwidth and delay demands. For instance, in a data center, the interactive message would not occupy much bandwidth, but it requires the rigorous demands for the delay. However, the existing QoS approaches are mainly bandwidth based, which are inappropriate for these scenarios. Hence, we propose the decoupled scheme in the OpenFlow networks to provide the centralized differential bandwidth and delay control. We leverage the mature HTB to manage the bandwidth. And we design the Queue Delay Management Scheme (QDMS) for queuing delay arrangement, as well as the Comprehensive Parameters based Dijkstra Route algorithm (CPDR) for the propagation delay control. The evaluation results verify the decoupling effectiveness. And the decoupled scheme can reduce the delay for high priority flows.
文摘In this paper, the open queueing network model is proposed for solving the problem of public transportation in cities. The vertices of the networks(i.e., the bus stops) are determined by means of the fuzzy clustering method. The arcs (i.e., the paths of the public transportation) can be set up by using the shortest path model in the time sense or the 0 1 integer programming method.Applying the statistics method, we can calculate the parameters(such as the passenger flow's distribution, passenger flow's transition probability, mean waiting time for the bus etc. ) of the public transportation network. In this paper, we suggest to divide the network into two or three stages to implement the public transportation system in the form of ``frog jumping' fast transfer and ``permeation' fast dispersion.Combining the computer simulation and the evaluation of the achievement and effect of public transportation system, we modify the model so as to solve the public transportation problem better.
基金supported by the National Natural Science Foundation of China(U19B2016)Zhejiang Provincial Key Lab of Data Storage and Transmission Technology,Hangzhou Dianzi University。
文摘To improve the recognition ability of communication jamming signals,Siamese Neural Network-based Open World Recognition(SNNOWR)is proposed.The algorithm can recognize known jamming classes,detect new(unknown)jamming classes,and unsupervised cluseter new classes.The network of SNN-OWR is trained supervised with paired input data consisting of two samples from a known dataset.On the one hand,the network is required to have the ability to distinguish whether two samples are from the same class.On the other hand,the latent distribution of known class is forced to approach their own unique Gaussian distribution,which is prepared for the subsequent open set testing.During the test,the unknown class detection process based on Gaussian probability density function threshold is designed,and an unsupervised clustering algorithm of the unknown jamming is realized by using the prior knowledge of known classes.The simulation results show that when the jamming-to-noise ratio is more than 0d B,the accuracy of SNN-OWR algorithm for known jamming classes recognition,unknown jamming detection and unsupervised clustering of unknown jamming is about 95%.This indicates that the SNN-OWR algorithm can make the effect of the recognition of unknown jamming be almost the same as that of known jamming.
基金supported by the State Grid Tianjin Electric Power Company Science and Technology Project (Grant No. KJ22-1-45)。
文摘After suffering from a grid blackout, distributed energy resources(DERs), such as local renewable energy and controllable distributed generators and energy storage can be used to restore loads enhancing the system’s resilience. In this study, a multi-source coordinated load restoration strategy was investigated for a distribution network with soft open points(SOPs). Here, the flexible regulation ability of the SOPs is fully utilized to improve the load restoration level while mitigating voltage deviations. Owing to the uncertainty, a scenario-based stochastic optimization approach was employed,and the load restoration problem was formulated as a mixed-integer nonlinear programming model. A computationally efficient solution algorithm was developed for the model using convex relaxation and linearization methods. The algorithm is organized into a two-stage structure, in which the energy storage system is dispatched in the first stage by solving a relaxed convex problem. In the second stage, an integer programming problem is calculated to acquire the outputs of both SOPs and power resources. A numerical test was conducted on both IEEE 33-bus and IEEE 123-bus systems to validate the effectiveness of the proposed strategy.
基金funded in part by National Natural Science Foundation of China(grant NO.61471347)National S&T Mayor Project of the Ministry of S&T of China(grant NO.2016ZX03001020-003)+1 种基金key program for international S&T Cooperation Program of China(grant NO.2014DFA11640)Shanghai Natural Science Foundation(grant NO.16ZR1435100)
文摘Due to 5G's stringent and uncertainty traffic requirements,open ecosystem would be one inevitable way to develop 5G.On the other hand,GPP based mobile communication becomes appealing recently attributed to its striking advantage in flexibility and re-configurability.In this paper,both the advantages and challenges of GPP platform are detailed analyzed.Furthermore,both GPP based software and hardware architectures for open 5G are presented and the performances of real-time signal processing and power consumption are also evaluated.The evaluation results indicate that turbo and power consumption may be another challengeable problem should be further solved to meet the requirements of realistic deployments.
文摘The lack of current network dynamics studies that evaluate the effects of new application and protocol deployment or long-term studies that observe the effect of incremental changes on the Internet, and the change in the overall stability of the Internet under various conditions and threats has made network monitoring challenging. A good understanding of the nature and type of network traffic is the key to solving congestion problems. In this paper we describe the architecture and implementation of a scalable network traffic moni-toring and analysis system. The gigabit interface on the monitoring system was configured to capture network traffic and the Multi Router Traffic Grapher (MRTG) and Webalizer produces graphical and detailed traffic analysis. This system is in use at the Obafemi Awolowo University, IleIfe, Nigeria;we describe how this system can be replicated in another environment.
文摘"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/
文摘"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/
文摘"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chirtese and English abstract, which can be downloaded after registration.
文摘"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/
文摘"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access;
文摘"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/
文摘"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration.
文摘"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can he downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/
文摘"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/
文摘"Geoscience Periodical Network of China" is composed of 233 Chinese geological journals, which covers all kinds of geological research fields of China. All papers of this site comprise English abstract, and some papers have figures with English description. Papers present as the PDF format with two types: (1) papers can be downloaded for opening access; and (2) the others provide both Chinese and English abstract, which can be downloaded after registration. Welcome to visit our website: http://www.geojournals.cn/
文摘Geoscience Periodical Network of China a"is s composed of 233 Chinese geological journals,which covers all kinds of geological research fi(elds of China.All papers of this site comprise English abstract,and some papers have figures with English description.Papers present as the