For the next generation optical switching networks, the intelligent control plane is a key enabling technique. In this paper, we review our recent research activities related to Generalized Multi-Protocol Label Switch...For the next generation optical switching networks, the intelligent control plane is a key enabling technique. In this paper, we review our recent research activities related to Generalized Multi-Protocol Label Switching (GMPLS) and Open Flow-based control planes for both Wave length Switched Optical Networks (WSON) and Elastic Optical Networks (EON).展开更多
Ethernet Ring Protection (ERP) introduced by ITU-T G.8032 Recommendation is a new type of packet-switched network protection technology, which can provide ring automatic protection switch. However, the Filtering Datab...Ethernet Ring Protection (ERP) introduced by ITU-T G.8032 Recommendation is a new type of packet-switched network protection technology, which can provide ring automatic protection switch. However, the Filtering Database (FDB) flush method adopted in the current ERP standard has the drawback of introducing a large amount of transient traffic overshoot caused by flooded Ethernet frames right after protection switching. In this article, we propose a G.8032 ERP scheme that uses FDB flush based on area to resolve this issue and investigate how the proposed scheme deals with the traffic flooding problem. The theoretical analysis and simulation show that the proposed scheme can effectively improve the performance of the Ethernet ring by decreasing the unnecessary FDB flush in comparison with the existing approaches.展开更多
Conventional optical burst switching(OBS)technique adopts purely statistical multiplex mechanismso that the bursts collide with each other very easily.To address this problem,a novel proactive con-tention avoidance sc...Conventional optical burst switching(OBS)technique adopts purely statistical multiplex mechanismso that the bursts collide with each other very easily.To address this problem,a novel proactive con-tention avoidance scheme is proposed,which assigns dedicated wavelengths to each ingress node,then st-numbering algorithm is used to construct the traffic load balanced spanning trees .In this way,contentioncan be eliminated at ingress nodes,and the amount of bursts that could be accommodated by ingressnodes will be maximized.Further,those unused wavelengths left by traffic load balanced spanning treeare also organized as partial trees to carry bursts,thus the link utilization can be improved effectively.Simulation result shows that our scheme can improve the burst loss performance significantly without thewavelength converters or optical buffers comparing to other popular routing and wavelength assignment(RWA)algorithms.展开更多
A new superstructure model of heat exchanger networks (HEN) with streamsplits based on rangers of streams supply temperatures and heat capacity flow rates is presented.The simultaneous optimal mathematical model of fl...A new superstructure model of heat exchanger networks (HEN) with streamsplits based on rangers of streams supply temperatures and heat capacity flow rates is presented.The simultaneous optimal mathematical model of flexible HEN synthesis is established too. Firstly,the streams with rangers of supply temperatures and/or the streams with the rangers of heat capacityflow rates are pretreated; Secondly, several rules are proposed to establish the superstructuremodel of HEN with splits and the simultaneous optimal mathematical model of flexible HEN; Thirdly,the improving genetic algorithm is applied to solve the mathematical model established at the secondstep effectively, and the original optimal structure of HEN based on the maximum operation limitingcondition can be obtained easily; Finally, the rules of heat exchange unit merged and the heat loadof heat exchanger relaxed are presented, the flexible configuration of HEN satisfied the operationcondition between the upper and down bounds of supply temperature and heat capacity flow rates canbe obtained based on the original optimal structure of HEN by means of these rules. A case studydemonstrates the method presented in this paper is effective展开更多
Differential modulation was widely used for wireless networks in which channel estimation was diffi-cult.Based on orthogonal design,a novel distributed differential space-time coding/decoding scheme forM-PSK modulatio...Differential modulation was widely used for wireless networks in which channel estimation was diffi-cult.Based on orthogonal design,a novel distributed differential space-time coding/decoding scheme forM-PSK modulations was proposed,which had a high code rate of 2/3 and second-order diversity for thetwo-user cooperative networks.The performance of decode-and-forward (DF) protocols was evaluated.Simulations show that the differential space-time modulation scheme in this paper has better bit error rate(BER) performance or higher code rate than the schemes proposed by Tarasak and Wang when interuserchannel states are good enough.The impacts of transmission error between two users for the whole systemBER performance were also investigated.展开更多
Increasing time-spent online has amplified users' exposure to tile tilreat oI miormanon leakage. Although existing security systems (such as firewalls and intrusion detection systems) can satisfy most of the securi...Increasing time-spent online has amplified users' exposure to tile tilreat oI miormanon leakage. Although existing security systems (such as firewalls and intrusion detection systems) can satisfy most of the security requirements of network administrators, they are not suitable for detecting the activities of applying the HTTP-tunnel technique to steal users' private information. This paper focuses on a network behavior-based method to address the limitations of the existing protection systems. At first, it analyzes the normal network behavior pattern over HTI'P traffic and select four features. Then, it pres- ents an anomaly-based detection model that applies a hierarchical clustering technique and a scoring mechanism. It also uses real-world data to validate that the selected features are useful. The experiments have demonstrated that the model could achieve over 93% hit-rate with only about 3% false- positive rate. It is regarded confidently that the approach is a complementary technique to the existing security systems.展开更多
To handle the handover challenge in Express Train Access Networks(ETAN).mobility fading effects in high speed railway environments should be addressed first.Based on the investigation of fading effects in this paper,w...To handle the handover challenge in Express Train Access Networks(ETAN).mobility fading effects in high speed railway environments should be addressed first.Based on the investigation of fading effects in this paper,we obtain two theoretical bounds:HOTiming upper bound and HO-Margin lower bound,which are helpful guidelines to study the handover challenge today and in the future.Then,we apply them to analyze performance of conventional handover technologies and our proposal in ETAN.This follow-up theory analyses and simulation experiment results demonstrate that the proposed handover solution can minimize handover time up to 4ms(which is the fastest one so far),and reduce HO-Margin to 0.16 dB at a train speed of 350km/h.展开更多
Driven by an ever-increasing num- ber of new services and applications, transport networks have been undergoing significant changes. In this paper, we describe several ex- citing technology directions associated with ...Driven by an ever-increasing num- ber of new services and applications, transport networks have been undergoing significant changes. In this paper, we describe several ex- citing technology directions associated with future optical transport networks. We review the status of 100G, which is now commercially available and entering volume deployments, and its applications in China. Beyond 100G is considered as the primary technology for the expansion of both channel and fiber capacity in tile near term, and several enabling techniques are introduced. Then, key technologies, prod- ucts, and future evolutionary options of Optical Transport Networks (OTNs) are extensively discussed. Compared to fixed bandwidth and coarse granularity of current WDM network, a flexible grid architecture is a desirable evolu- tion trend, and key technologies and challenges are described. Finally, we illustrate the multi-dimension convergences in terms of IP and optical, Packet OTN (P-OTN), as well as Electronic Integrated Circuits (EICs) and Photonic Integrated Cimuits (PICs). Transport networks are therefore in the process of be- coming more broadband, robust, flexible, cost-effective and lower-power-consumptive.展开更多
With the development of network economy, e-commerce platform has increasingly become a worldwide trading places of various kinds of products and services. Therefore some scholars consider, intermediaries, under the ra...With the development of network economy, e-commerce platform has increasingly become a worldwide trading places of various kinds of products and services. Therefore some scholars consider, intermediaries, under the rapid development of information technology, will gradually withdrew from the historical stage. This article carried on the thorough analysis for the reasons of the existence of electronic intermediaries, and discusses the new development space and prospect of new middlemen, from the perspective of information asymmetry of the network environment.展开更多
In this paper, architecture of softswitch-based Next Generation Network (NGN) system and Session Initiation Protocol (SIP) are studied briefly, and the problems on the openness and extensibility of normal remote video...In this paper, architecture of softswitch-based Next Generation Network (NGN) system and Session Initiation Protocol (SIP) are studied briefly, and the problems on the openness and extensibility of normal remote video-monitoring system (RVMS) are analyzed. Then a RVMS framework model based on softswitch is given. Furthermore, designation and realization of the system based on T 6000 Softswitch Platform is provided. The innovation is considering the RVMS as a part of softswitch system. It is a feasible scheme for implementing next generation video-monitoring system based on broadband IP technique.展开更多
with the development of science and technology, smart home systems require better, faster to meet the needs of human. In order to achieve this goal, the human-machine-items all need to interact each other with underst...with the development of science and technology, smart home systems require better, faster to meet the needs of human. In order to achieve this goal, the human-machine-items all need to interact each other with understand, efficient and speedy. Cps could unify combination with the human-machine-items; realize the interaction between the physical nformation and the cyber world. However, information interaction and the control task needs to be completed in a valid time. Therefore, the transform delay control strategy becomes more and more important. This paper analysis Markov delay control strategy for smart home systems, which might help the system decrease the transmission delay.展开更多
With the development of information technology in the past 10 years, computers have been widely used in the field of English teaching. This paper, based on a computer-mediated communication (CMC) program carried out i...With the development of information technology in the past 10 years, computers have been widely used in the field of English teaching. This paper, based on a computer-mediated communication (CMC) program carried out in Civil Aviation Flight University of China, aims to investigate the effectiveness of the use of online chat in college English teaching practice.展开更多
文摘For the next generation optical switching networks, the intelligent control plane is a key enabling technique. In this paper, we review our recent research activities related to Generalized Multi-Protocol Label Switching (GMPLS) and Open Flow-based control planes for both Wave length Switched Optical Networks (WSON) and Elastic Optical Networks (EON).
基金supported partially by National Science and Technology Major Project of the Ministry of Science and Technology of China under Grant No.2011ZX03005-004-03 a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions-Information and Communication Engineering,Natural Science Foundation of the Higher Education Institutions of Jiangsu Province,China under Grant No.10KJA510037+1 种基金 Open Research Fund of Key Lab of Broadband Wireless Communication and Sensor Network Technology(Nanjing University of Posts and Telecommunications),Ministry of Education under Grant No.NYKL201108 Natural Science Foundation of Nanjing University of Posts and Telecommunications under Grant No.NY209002
文摘Ethernet Ring Protection (ERP) introduced by ITU-T G.8032 Recommendation is a new type of packet-switched network protection technology, which can provide ring automatic protection switch. However, the Filtering Database (FDB) flush method adopted in the current ERP standard has the drawback of introducing a large amount of transient traffic overshoot caused by flooded Ethernet frames right after protection switching. In this article, we propose a G.8032 ERP scheme that uses FDB flush based on area to resolve this issue and investigate how the proposed scheme deals with the traffic flooding problem. The theoretical analysis and simulation show that the proposed scheme can effectively improve the performance of the Ethernet ring by decreasing the unnecessary FDB flush in comparison with the existing approaches.
基金supported by the National Natural Science Foundation of China(No.60572050)the National High Technology Research and Development Programme of China(No.2008AA01Z211)
文摘Conventional optical burst switching(OBS)technique adopts purely statistical multiplex mechanismso that the bursts collide with each other very easily.To address this problem,a novel proactive con-tention avoidance scheme is proposed,which assigns dedicated wavelengths to each ingress node,then st-numbering algorithm is used to construct the traffic load balanced spanning trees .In this way,contentioncan be eliminated at ingress nodes,and the amount of bursts that could be accommodated by ingressnodes will be maximized.Further,those unused wavelengths left by traffic load balanced spanning treeare also organized as partial trees to carry bursts,thus the link utilization can be improved effectively.Simulation result shows that our scheme can improve the burst loss performance significantly without thewavelength converters or optical buffers comparing to other popular routing and wavelength assignment(RWA)algorithms.
基金Supported by the State Major Basic Research Department Program of China (No. G20000263) and the Deutsche Forschungs- gemeinschaft(DFG)(No. RO294/9).
文摘A new superstructure model of heat exchanger networks (HEN) with streamsplits based on rangers of streams supply temperatures and heat capacity flow rates is presented.The simultaneous optimal mathematical model of flexible HEN synthesis is established too. Firstly,the streams with rangers of supply temperatures and/or the streams with the rangers of heat capacityflow rates are pretreated; Secondly, several rules are proposed to establish the superstructuremodel of HEN with splits and the simultaneous optimal mathematical model of flexible HEN; Thirdly,the improving genetic algorithm is applied to solve the mathematical model established at the secondstep effectively, and the original optimal structure of HEN based on the maximum operation limitingcondition can be obtained easily; Finally, the rules of heat exchange unit merged and the heat loadof heat exchanger relaxed are presented, the flexible configuration of HEN satisfied the operationcondition between the upper and down bounds of supply temperature and heat capacity flow rates canbe obtained based on the original optimal structure of HEN by means of these rules. A case studydemonstrates the method presented in this paper is effective
基金the National High Technology Research and Development Programme of China(No.2006AA123320)
文摘Differential modulation was widely used for wireless networks in which channel estimation was diffi-cult.Based on orthogonal design,a novel distributed differential space-time coding/decoding scheme forM-PSK modulations was proposed,which had a high code rate of 2/3 and second-order diversity for thetwo-user cooperative networks.The performance of decode-and-forward (DF) protocols was evaluated.Simulations show that the differential space-time modulation scheme in this paper has better bit error rate(BER) performance or higher code rate than the schemes proposed by Tarasak and Wang when interuserchannel states are good enough.The impacts of transmission error between two users for the whole systemBER performance were also investigated.
基金Supported by the National Natural Science Foundation of China(No.61070185,61003261)the Knowledge Innovation Program of the Chinese Academy of Sciences(No.XDA06030200)
文摘Increasing time-spent online has amplified users' exposure to tile tilreat oI miormanon leakage. Although existing security systems (such as firewalls and intrusion detection systems) can satisfy most of the security requirements of network administrators, they are not suitable for detecting the activities of applying the HTTP-tunnel technique to steal users' private information. This paper focuses on a network behavior-based method to address the limitations of the existing protection systems. At first, it analyzes the normal network behavior pattern over HTI'P traffic and select four features. Then, it pres- ents an anomaly-based detection model that applies a hierarchical clustering technique and a scoring mechanism. It also uses real-world data to validate that the selected features are useful. The experiments have demonstrated that the model could achieve over 93% hit-rate with only about 3% false- positive rate. It is regarded confidently that the approach is a complementary technique to the existing security systems.
基金supported by the National Basic Research Program of China (973 Program)(No.2012CB315606 and 2010CB328201)
文摘To handle the handover challenge in Express Train Access Networks(ETAN).mobility fading effects in high speed railway environments should be addressed first.Based on the investigation of fading effects in this paper,we obtain two theoretical bounds:HOTiming upper bound and HO-Margin lower bound,which are helpful guidelines to study the handover challenge today and in the future.Then,we apply them to analyze performance of conventional handover technologies and our proposal in ETAN.This follow-up theory analyses and simulation experiment results demonstrate that the proposed handover solution can minimize handover time up to 4ms(which is the fastest one so far),and reduce HO-Margin to 0.16 dB at a train speed of 350km/h.
基金supported by the National Natural Science Foundation of China under GrantNo. 61171076National 863 Project underGrant No. 2012AA011303National 973 Project under Grant No. 2010CB328200(2010CB328201)
文摘Driven by an ever-increasing num- ber of new services and applications, transport networks have been undergoing significant changes. In this paper, we describe several ex- citing technology directions associated with future optical transport networks. We review the status of 100G, which is now commercially available and entering volume deployments, and its applications in China. Beyond 100G is considered as the primary technology for the expansion of both channel and fiber capacity in tile near term, and several enabling techniques are introduced. Then, key technologies, prod- ucts, and future evolutionary options of Optical Transport Networks (OTNs) are extensively discussed. Compared to fixed bandwidth and coarse granularity of current WDM network, a flexible grid architecture is a desirable evolu- tion trend, and key technologies and challenges are described. Finally, we illustrate the multi-dimension convergences in terms of IP and optical, Packet OTN (P-OTN), as well as Electronic Integrated Circuits (EICs) and Photonic Integrated Cimuits (PICs). Transport networks are therefore in the process of be- coming more broadband, robust, flexible, cost-effective and lower-power-consumptive.
文摘With the development of network economy, e-commerce platform has increasingly become a worldwide trading places of various kinds of products and services. Therefore some scholars consider, intermediaries, under the rapid development of information technology, will gradually withdrew from the historical stage. This article carried on the thorough analysis for the reasons of the existence of electronic intermediaries, and discusses the new development space and prospect of new middlemen, from the perspective of information asymmetry of the network environment.
文摘In this paper, architecture of softswitch-based Next Generation Network (NGN) system and Session Initiation Protocol (SIP) are studied briefly, and the problems on the openness and extensibility of normal remote video-monitoring system (RVMS) are analyzed. Then a RVMS framework model based on softswitch is given. Furthermore, designation and realization of the system based on T 6000 Softswitch Platform is provided. The innovation is considering the RVMS as a part of softswitch system. It is a feasible scheme for implementing next generation video-monitoring system based on broadband IP technique.
文摘with the development of science and technology, smart home systems require better, faster to meet the needs of human. In order to achieve this goal, the human-machine-items all need to interact each other with understand, efficient and speedy. Cps could unify combination with the human-machine-items; realize the interaction between the physical nformation and the cyber world. However, information interaction and the control task needs to be completed in a valid time. Therefore, the transform delay control strategy becomes more and more important. This paper analysis Markov delay control strategy for smart home systems, which might help the system decrease the transmission delay.
文摘With the development of information technology in the past 10 years, computers have been widely used in the field of English teaching. This paper, based on a computer-mediated communication (CMC) program carried out in Civil Aviation Flight University of China, aims to investigate the effectiveness of the use of online chat in college English teaching practice.