Cloud computing is very attractive for schools, research institutions and enterpri- ses which need reducing IT costs, improving computing platform sharing and meeting lice- nse constraints. Sharing, management and on-...Cloud computing is very attractive for schools, research institutions and enterpri- ses which need reducing IT costs, improving computing platform sharing and meeting lice- nse constraints. Sharing, management and on- demand allocation of network resources are particularly important in Cloud computing. Ho- wever, nearly all-current available cloud com- puting platforms are either proprietary or their software infrastructure is invisible to the rese- arch community except for a few open-source platforms. For universities and research insti- tutes, more open and testable experimental plat- forms are needed in a lab-level with PCs. In this paper, a platform of infrastructure resou- rce sharing system （Platform as a Service （PaaS）） is developed in virtual Cloud comput- hug environment. Its architecture, core modules, main functions, design and operational envir- onment and applications are introduced in de- tail. It has good expandability and can impr- ove resource sharing and utilization and is app- lied to regular computer science teaching and research process.展开更多
The explosive increase in data traffic requires networks to provide higher capacity and long-haul transmission capabilities.This paper introduces new results on high-order modulation and efficient Digital Signal Proce...The explosive increase in data traffic requires networks to provide higher capacity and long-haul transmission capabilities.This paper introduces new results on high-order modulation and efficient Digital Signal Processing algorithms to reduce various transmission limitations in coherent receiving systems.Polarization Division Multiplexed Quadrature Phase Shift Keying(PDM-QPSK)is deployed to reach high bit rates,provides modified digital clock recovery,and allows BER-Aided Constant Modulus Algorithm(BA-CMA)equalising.A Soft Decision-Forward Error Correction(SD-FEC)algorithm and a joint scheme with timing recovery and adaptive equaliser are used to achieve better performance.A compact coherent transceiver is also developed.These techniques have been applied in the largest 100 G Optical Transport Network(OTN)deployment in the world,the backbone expansion project for Phase 3 of the China Education and Research Network(CERNET),with a total transmission length of 10 000 km.展开更多
Multimedia teaching managemem system based on SIP ＆ P2P is proposed on account of the existing deficiency on video teaching of distance education. The designed P2P-SIP system applies SIP protocol to realize the under...Multimedia teaching managemem system based on SIP ＆ P2P is proposed on account of the existing deficiency on video teaching of distance education. The designed P2P-SIP system applies SIP protocol to realize the underlying DHT, which guarantees zero-configuration, robustness and adaptability in P2P system. And maximum improvement in performance of the networks for multimedia system can be implemented by rapid networking and information sharing technology of the underlying P2P networks as well as fast call and location technology of SIP system. Experiments indicates that multimedia teaching management system based on SIP ＆ P2P could meet the requirement of system design on data latency and calling location.展开更多
基金supported by the Coalition for National Science Fundingunder Grant No.61150110486the Central University Funding under Grant No.ZYGX2013J073
文摘Cloud computing is very attractive for schools, research institutions and enterpri- ses which need reducing IT costs, improving computing platform sharing and meeting lice- nse constraints. Sharing, management and on- demand allocation of network resources are particularly important in Cloud computing. Ho- wever, nearly all-current available cloud com- puting platforms are either proprietary or their software infrastructure is invisible to the rese- arch community except for a few open-source platforms. For universities and research insti- tutes, more open and testable experimental plat- forms are needed in a lab-level with PCs. In this paper, a platform of infrastructure resou- rce sharing system （Platform as a Service （PaaS）） is developed in virtual Cloud comput- hug environment. Its architecture, core modules, main functions, design and operational envir- onment and applications are introduced in de- tail. It has good expandability and can impr- ove resource sharing and utilization and is app- lied to regular computer science teaching and research process.
基金supported by the National Natural Science Foundation of China under Grant No. 60932004the National High Technical Research and Development Program of China (863 Program) under Grants No. 2012AA011301,No. 2012AA011303
文摘The explosive increase in data traffic requires networks to provide higher capacity and long-haul transmission capabilities.This paper introduces new results on high-order modulation and efficient Digital Signal Processing algorithms to reduce various transmission limitations in coherent receiving systems.Polarization Division Multiplexed Quadrature Phase Shift Keying(PDM-QPSK)is deployed to reach high bit rates,provides modified digital clock recovery,and allows BER-Aided Constant Modulus Algorithm(BA-CMA)equalising.A Soft Decision-Forward Error Correction(SD-FEC)algorithm and a joint scheme with timing recovery and adaptive equaliser are used to achieve better performance.A compact coherent transceiver is also developed.These techniques have been applied in the largest 100 G Optical Transport Network(OTN)deployment in the world,the backbone expansion project for Phase 3 of the China Education and Research Network(CERNET),with a total transmission length of 10 000 km.
文摘Multimedia teaching managemem system based on SIP ＆ P2P is proposed on account of the existing deficiency on video teaching of distance education. The designed P2P-SIP system applies SIP protocol to realize the underlying DHT, which guarantees zero-configuration, robustness and adaptability in P2P system. And maximum improvement in performance of the networks for multimedia system can be implemented by rapid networking and information sharing technology of the underlying P2P networks as well as fast call and location technology of SIP system. Experiments indicates that multimedia teaching management system based on SIP ＆ P2P could meet the requirement of system design on data latency and calling location.
