In radio receivers,complete implementation of the software defined radio(SDR) concept is mainly limited by frontend.Based on bandpass sampling(BPS) theory,a flexible digital frontend(DFE) platform for SDR receiver is ...In radio receivers,complete implementation of the software defined radio(SDR) concept is mainly limited by frontend.Based on bandpass sampling(BPS) theory,a flexible digital frontend(DFE) platform for SDR receiver is designed.In order to increase the processing speed,Gigabit Ethernet was applied in the platform at speed of 5×10~8 bit/s.By appropriate design of interpolant according to the position of input RF signals,multi-band receiving can be realized in the platform with suppression more than 35 d B without changing hardware.展开更多
Over the past few decades, the world has witnessed a rapid growth in mobile and wireless networks（MWNs） which significantly change human life. However, proliferating mobile demands lead to several intractable challe...Over the past few decades, the world has witnessed a rapid growth in mobile and wireless networks（MWNs） which significantly change human life. However, proliferating mobile demands lead to several intractable challenges that MWN has to face. Software-defined network is expected as a promising way for future network and has captured growing attention. Network virtualization is an essential feature in software-defined wireless network（SDWN）, and it brings two new entities, physical networks and virtual networks. Accordingly, efficiently assigning spectrum resource to virtual networks is one of the fundamental problems in SDWN. Directly orienting towards the spectrum resource allocation problem, firstly, the fluctuation features of virtual network requirements in SDWN are researched, and the opportunistic spectrum sharing method is introduced to SDWN. Then, the problem is proved as NP-hardness. After that, a dynamic programming and graph theory based spectrum sharing algorithm is proposed.Simulations demonstrate that the opportunistic spectrum sharing method conspicuously improves the system performance up to around 20%–30% in SDWN, and the proposed algorithm achieves more efficient performance.展开更多
Large latency of applications will bring revenue loss to cloud infrastructure providers in the cloud data center. The existing controllers of software-defined networking architecture can fetch and process traffic info...Large latency of applications will bring revenue loss to cloud infrastructure providers in the cloud data center. The existing controllers of software-defined networking architecture can fetch and process traffic information in the network. Therefore, the controllers can only optimize the network latency of applications. However, the serving latency of applications is also an important factor in delivered user-experience for arrival requests. Unintelligent request routing will cause large serving latency if arrival requests are allocated to overloaded virtual machines. To deal with the request routing problem, this paper proposes the workload-aware software-defined networking controller architecture. Then, request routing algorithms are proposed to minimize the total round trip time for every type of request by considering the congestion in the network and the workload in virtual machines（VMs）. This paper finally provides the evaluation of the proposed algorithms in a simulated prototype. The simulation results show that the proposed methodology is efficient compared with the existing approaches.展开更多
Software testing is a very important phase of the software development process. It is a very difficult job for a software manager to allocate optimally the financial budget to a software project during testing. In thi...Software testing is a very important phase of the software development process. It is a very difficult job for a software manager to allocate optimally the financial budget to a software project during testing. In this paper the problem of optimal allocation of the software testing cost is studied. There exist several models focused on the development of software costs measuring the number of software errors remaining in the software during testing. The purpose of this paper is to use these models to formulate the optimization problems of resource allocation: Minimization of the total number of software errors remaining in the system. On the assumption that a software project consists of some independent modules, the presented approach extends previous work by defining new goal functions and extending the primary assumption and precondition.展开更多
基于IPv6的段路由(segment routing over IPv6,SRv6)作为下一代网络架构的关键使能技术,通过引入灵活的段路由转发平面,为提升网络智能化水平、拓展业务服务能力带来革新机遇.旨在全面梳理近年来SRv6的演进趋势和研究现状.首先,系统总结...基于IPv6的段路由(segment routing over IPv6,SRv6)作为下一代网络架构的关键使能技术,通过引入灵活的段路由转发平面,为提升网络智能化水平、拓展业务服务能力带来革新机遇.旨在全面梳理近年来SRv6的演进趋势和研究现状.首先,系统总结SRv6在网络架构与性能、网络管理与运维以及新兴业务支撑等方面的应用,凸显了SRv6精细调度、灵活编程、服务融合等独特优势.与此同时,深入剖析SRv6在性能与效率、可靠性与安全性、部署与演进策略这3个方面所面临的关键挑战,并重点讨论当前主流的解决思路和发展趋势.最后,立足产业生态构建、人工智能引入、行业融合创新等视角,对SRv6未来的发展方向和挑战进行前瞻性思考和展望.研究成果将为运营商构建开放、智能、安全的新一代网络提供理论参考和实践指导.展开更多
The dual-motor controller system is one of the key components in the multi-power architecture of new energy vehicles and is crucial to the safe operation of the vehicle.From the perspective of functional safety,this a...The dual-motor controller system is one of the key components in the multi-power architecture of new energy vehicles and is crucial to the safe operation of the vehicle.From the perspective of functional safety,this article takes the torque safety goal of"avoiding unexpected acceleration of the vehicle due to unexpected acceleration torque"as an example to explore various software and hardware architecture implementation methods,and analysis the test scheme covering multiple stages such as HIL/PowerHIL testing,bench testing and vehicle testing to verify the effectiveness of the safety path.Through the verification of the safety strategy,it provides innovative ideas for the functional safety design and testing of the electric drive control system,which is expected to provide a reference for improving the overall safety of new energy vehicles.展开更多
空间飞行器的智能自主水平和在轨稳定运行能力是提升航天任务成功率的关键,而软件自适应演化技术则是实现这一目标的重要途径,并成为当前软件工程领域的研究热点.首先对空间飞行器控制软件自适应演化的研究现状和存在问题进行综述.然后...空间飞行器的智能自主水平和在轨稳定运行能力是提升航天任务成功率的关键,而软件自适应演化技术则是实现这一目标的重要途径,并成为当前软件工程领域的研究热点.首先对空间飞行器控制软件自适应演化的研究现状和存在问题进行综述.然后,针对空间飞行器在轨运行环境的开放性、宿主计算资源的有限性以及飞行任务对实时响应的高要求,提出名为MAPE-KV(monitor-analyze-plan-execute over knowledge and verification)的空间飞行器控制软件在轨自适应可信演化框架.此外,在该框架的指导下对航天器软件应用逻辑、自适应控制逻辑、可信保障逻辑以及支撑知识库进行设计.最后,通过非预期故障和业务变更两类典型案例验证所提框架的有效性,仿真结果表明该方法能够有效应对星载软件在运行过程中面临的异常事件挑战.展开更多
软件定义自组网(Software Defined Mobile Ad Hoc Network,SD-MANET)融合了软件定义网络(Software Defined Network,SDN)集中控制优势和移动自组网(Mobile Ad Hoc Network,MANET)的动态组网优势,但Mininet等现有仿真平台在动态拓扑与扩...软件定义自组网(Software Defined Mobile Ad Hoc Network,SD-MANET)融合了软件定义网络(Software Defined Network,SDN)集中控制优势和移动自组网(Mobile Ad Hoc Network,MANET)的动态组网优势,但Mininet等现有仿真平台在动态拓扑与扩展性等方面存在显著局限,严重制约了其关键算法的研究。针对这一问题,提出基于网络模拟器-3(Network Simulator-3,NS-3)的仿真平台NS3-SDMANET,具体工作包括:基于NS-3框架实现了SD-MANET网络层关键特性的仿真;基于远程过程调用对平台功能进行封装,并提供可编程接口。战术网的测试案例表明:NS3-SDMANET在SD-MANET网络层关键特性仿真方面表现优异,能够有效支撑SD-MANET网络层算法的高效验证与性能评估,为相关研究提供了高扩展性的基础仿真环境。展开更多
基金Project(2013QNA49)supported by the Fundamental Research Funds for the Central Universities,China
文摘In radio receivers,complete implementation of the software defined radio(SDR) concept is mainly limited by frontend.Based on bandpass sampling(BPS) theory,a flexible digital frontend(DFE) platform for SDR receiver is designed.In order to increase the processing speed,Gigabit Ethernet was applied in the platform at speed of 5×10~8 bit/s.By appropriate design of interpolant according to the position of input RF signals,multi-band receiving can be realized in the platform with suppression more than 35 d B without changing hardware.
基金supported by the National Natural Science Foundation of China(6102100161133015+4 种基金61171065)the National Natural Science Foundation of China(973 Program)(2013CB329001)the National High Technology ResearchDevelopment Program(863 Program)(2013AA0106052013AA013500)
文摘Over the past few decades, the world has witnessed a rapid growth in mobile and wireless networks（MWNs） which significantly change human life. However, proliferating mobile demands lead to several intractable challenges that MWN has to face. Software-defined network is expected as a promising way for future network and has captured growing attention. Network virtualization is an essential feature in software-defined wireless network（SDWN）, and it brings two new entities, physical networks and virtual networks. Accordingly, efficiently assigning spectrum resource to virtual networks is one of the fundamental problems in SDWN. Directly orienting towards the spectrum resource allocation problem, firstly, the fluctuation features of virtual network requirements in SDWN are researched, and the opportunistic spectrum sharing method is introduced to SDWN. Then, the problem is proved as NP-hardness. After that, a dynamic programming and graph theory based spectrum sharing algorithm is proposed.Simulations demonstrate that the opportunistic spectrum sharing method conspicuously improves the system performance up to around 20%–30% in SDWN, and the proposed algorithm achieves more efficient performance.
基金supported by the National Postdoctoral Science Foundation of China(2014M550068)
文摘Large latency of applications will bring revenue loss to cloud infrastructure providers in the cloud data center. The existing controllers of software-defined networking architecture can fetch and process traffic information in the network. Therefore, the controllers can only optimize the network latency of applications. However, the serving latency of applications is also an important factor in delivered user-experience for arrival requests. Unintelligent request routing will cause large serving latency if arrival requests are allocated to overloaded virtual machines. To deal with the request routing problem, this paper proposes the workload-aware software-defined networking controller architecture. Then, request routing algorithms are proposed to minimize the total round trip time for every type of request by considering the congestion in the network and the workload in virtual machines（VMs）. This paper finally provides the evaluation of the proposed algorithms in a simulated prototype. The simulation results show that the proposed methodology is efficient compared with the existing approaches.
文摘Software testing is a very important phase of the software development process. It is a very difficult job for a software manager to allocate optimally the financial budget to a software project during testing. In this paper the problem of optimal allocation of the software testing cost is studied. There exist several models focused on the development of software costs measuring the number of software errors remaining in the software during testing. The purpose of this paper is to use these models to formulate the optimization problems of resource allocation: Minimization of the total number of software errors remaining in the system. On the assumption that a software project consists of some independent modules, the presented approach extends previous work by defining new goal functions and extending the primary assumption and precondition.
文摘基于IPv6的段路由(segment routing over IPv6,SRv6)作为下一代网络架构的关键使能技术,通过引入灵活的段路由转发平面,为提升网络智能化水平、拓展业务服务能力带来革新机遇.旨在全面梳理近年来SRv6的演进趋势和研究现状.首先,系统总结SRv6在网络架构与性能、网络管理与运维以及新兴业务支撑等方面的应用,凸显了SRv6精细调度、灵活编程、服务融合等独特优势.与此同时,深入剖析SRv6在性能与效率、可靠性与安全性、部署与演进策略这3个方面所面临的关键挑战,并重点讨论当前主流的解决思路和发展趋势.最后,立足产业生态构建、人工智能引入、行业融合创新等视角,对SRv6未来的发展方向和挑战进行前瞻性思考和展望.研究成果将为运营商构建开放、智能、安全的新一代网络提供理论参考和实践指导.
文摘The dual-motor controller system is one of the key components in the multi-power architecture of new energy vehicles and is crucial to the safe operation of the vehicle.From the perspective of functional safety,this article takes the torque safety goal of"avoiding unexpected acceleration of the vehicle due to unexpected acceleration torque"as an example to explore various software and hardware architecture implementation methods,and analysis the test scheme covering multiple stages such as HIL/PowerHIL testing,bench testing and vehicle testing to verify the effectiveness of the safety path.Through the verification of the safety strategy,it provides innovative ideas for the functional safety design and testing of the electric drive control system,which is expected to provide a reference for improving the overall safety of new energy vehicles.
文摘空间飞行器的智能自主水平和在轨稳定运行能力是提升航天任务成功率的关键,而软件自适应演化技术则是实现这一目标的重要途径,并成为当前软件工程领域的研究热点.首先对空间飞行器控制软件自适应演化的研究现状和存在问题进行综述.然后,针对空间飞行器在轨运行环境的开放性、宿主计算资源的有限性以及飞行任务对实时响应的高要求,提出名为MAPE-KV(monitor-analyze-plan-execute over knowledge and verification)的空间飞行器控制软件在轨自适应可信演化框架.此外,在该框架的指导下对航天器软件应用逻辑、自适应控制逻辑、可信保障逻辑以及支撑知识库进行设计.最后,通过非预期故障和业务变更两类典型案例验证所提框架的有效性,仿真结果表明该方法能够有效应对星载软件在运行过程中面临的异常事件挑战.
文摘软件定义自组网(Software Defined Mobile Ad Hoc Network,SD-MANET)融合了软件定义网络(Software Defined Network,SDN)集中控制优势和移动自组网(Mobile Ad Hoc Network,MANET)的动态组网优势,但Mininet等现有仿真平台在动态拓扑与扩展性等方面存在显著局限,严重制约了其关键算法的研究。针对这一问题,提出基于网络模拟器-3(Network Simulator-3,NS-3)的仿真平台NS3-SDMANET,具体工作包括:基于NS-3框架实现了SD-MANET网络层关键特性的仿真;基于远程过程调用对平台功能进行封装,并提供可编程接口。战术网的测试案例表明:NS3-SDMANET在SD-MANET网络层关键特性仿真方面表现优异,能够有效支撑SD-MANET网络层算法的高效验证与性能评估,为相关研究提供了高扩展性的基础仿真环境。
