期刊文献+
共找到22篇文章
< 1 2 >
每页显示 20 50 100
一种状态可编程交换机的流量控制方案
1
作者 曹绚丽 陈晓 宋磊 《电子设计工程》 2024年第2期147-151,共5页
随着网络应用的功能和服务需求的多样化,网络流量的类别也逐渐丰富,如何为不同类别的流量提供区分的QoS服务成为亟需解决的问题。该文为基于SDN网络的交换机增加了一种可编程的流量控制机制,控制面通过开放的编程接口配置交换机,使其为... 随着网络应用的功能和服务需求的多样化,网络流量的类别也逐渐丰富,如何为不同类别的流量提供区分的QoS服务成为亟需解决的问题。该文为基于SDN网络的交换机增加了一种可编程的流量控制机制,控制面通过开放的编程接口配置交换机,使其为不同数据流提供带宽保障。提出并实现了一种针对优先级队列的调度算法,为流量构建其所需容量的数据传输通道,保障了网络资源的高效利用。实验结果显示,各类流量可以按照指定的带宽执行转发,其他流量发生变化时,给定流量的带宽波动不超过2%;且在长度为78 Bytes的小包情况下,高优先级的流量丢包率控制在1%以下。 展开更多
关键词 SDN网络 状态可编程交换 队列调度 带宽保障
下载PDF
基于Bloom过滤的多协议无状态交换架构研究
2
作者 彭耘 《深圳职业技术学院学报》 CAS 2014年第1期20-23,28,共5页
结合Bloom过滤和多协议标记交换(Multi Protocol Label Switching,MPLS)技术,提出一种替代MPLS的多协议无状态分组交换框架.将该交换框架应用到组播VPN业务应用中,可以使运营商的核心路由器的分组转发不依赖于组播树的数量,节省了标签资... 结合Bloom过滤和多协议标记交换(Multi Protocol Label Switching,MPLS)技术,提出一种替代MPLS的多协议无状态分组交换框架.将该交换框架应用到组播VPN业务应用中,可以使运营商的核心路由器的分组转发不依赖于组播树的数量,节省了标签资源.同时通过将路由决策策略推向用户路由器,进而减轻了运营商边缘路由器的处理负荷.该方法即具有MPLS的灵活性,又能适应组播通信中组播路径状态管理的需要. 展开更多
关键词 多协议标记交换 Bloom过滤编码 多协议无状态交换
下载PDF
一种基于状态机的SDN控制器中交换机状态管理方法
3
作者 许延伟 黄志林 +1 位作者 徐晔 刘永红 《电脑知识与技术》 2018年第6X期35-37,共3页
作为SDN网络的核心,SDN控制器的鲁棒性是影响SDN网络的关键因素之一。由于SDN网络中管理通道的不可靠性所带来的交换机连接状态的变化是影响SDN控制器工作稳定性的主要原因。该文通过引入多个交换机的新型状态,并基于状态机(FSM)对交换... 作为SDN网络的核心,SDN控制器的鲁棒性是影响SDN网络的关键因素之一。由于SDN网络中管理通道的不可靠性所带来的交换机连接状态的变化是影响SDN控制器工作稳定性的主要原因。该文通过引入多个交换机的新型状态,并基于状态机(FSM)对交换机状态之间的变化进行精细化管理,使得其可以应对交换机的短暂性掉线等情形,从而可以大大提高SDN控制器的鲁棒性。 展开更多
关键词 软件定义网络 OpenFlow SDN控制器 交换状态 状态
下载PDF
交换机监测与ARP欺骗主动防御系统的设计和实现 被引量:1
4
作者 肖川豫 陈孟 +1 位作者 刘晟 汪磊 《计算机时代》 2011年第1期20-22,共3页
ARP病毒具有极大的破坏性,针对它的原理,提出了基于SNMP的主动防御ARP欺骗的解决方案,创新性地利用SNMP协议将交换机状态监测和管理引入ARP防御体系中,以尽早发现和维护出现故障的交换机,确保整个计算机网络的稳定性。该方案特别适合在... ARP病毒具有极大的破坏性,针对它的原理,提出了基于SNMP的主动防御ARP欺骗的解决方案,创新性地利用SNMP协议将交换机状态监测和管理引入ARP防御体系中,以尽早发现和维护出现故障的交换机,确保整个计算机网络的稳定性。该方案特别适合在较大规模的网络中部署,其代价小,效率高。 展开更多
关键词 SNMP 交换状态监测 ARP主动防御 网络稳定性
下载PDF
多模态网络可编程交换机的可配置限速机制研究
5
作者 曹绚丽 陈晓 宋磊 《网络新媒体技术》 2023年第6期44-50,共7页
为满足多模态网络环境的底座设备对不同网络模态的业务处理需求,网络管理人员需要为不同网络模态的流量分配其所需的数据传输通道。本文基于软件定义网络(SDN)架构对新型网络模态的支持,为多模态网络环境底座设备的软件交换机提供可动... 为满足多模态网络环境的底座设备对不同网络模态的业务处理需求,网络管理人员需要为不同网络模态的流量分配其所需的数据传输通道。本文基于软件定义网络(SDN)架构对新型网络模态的支持,为多模态网络环境底座设备的软件交换机提供可动态配置的流量控制模块,控制面扩展了南向协议(POF)中端口状态更新消息用于数据面上报实时流量状态信息,控制器根据网络拓扑状态下发指令更新消息配置各种流量的最大转发速率;同时在数据面交换机的输出侧设计并实现了一种基于信用量的流量整形器,对端口队列进行统一调度,确保流量以不超过指定阈值的速率输出,保障了网络带宽资源的高效利用。针对多个线程读写队列引发的读写一致性问题,本文引入了无锁化方案,使用DPDK的原子保证操作和无锁环形队列,避免了读写过程中频繁的加锁和解锁。实验结果显示,与朴素的基于共享内存和互斥锁的限速方案相比,本方案可以有效降低上限带宽传输时的速率抖动,当限速阈值为3 Gbit/s时,可降低限速抖动约54%。 展开更多
关键词 软件定义网络 状态可编程交换 动态配置 流量整形 队列调度
下载PDF
赤泥对重金属污染土壤的修复效果 被引量:3
6
作者 李怡帆 罗亚红 孙剑辉 《吉林农业(学术版)》 2010年第6期142-142,共1页
采用土壤培养实验,研究添加赤泥对土壤中Pb和Zn生物有效性的影响。同时,对于添加赤泥后,长喙田菁的生长情况作出对照分析。结果表明,添加赤泥到重金属污染的土壤,可以有效降低土壤中的交换态Pb和Zn以及生物有效性Pb和Zn德含量。与对照相... 采用土壤培养实验,研究添加赤泥对土壤中Pb和Zn生物有效性的影响。同时,对于添加赤泥后,长喙田菁的生长情况作出对照分析。结果表明,添加赤泥到重金属污染的土壤,可以有效降低土壤中的交换态Pb和Zn以及生物有效性Pb和Zn德含量。与对照相比,培养了1-6个月后,3%的赤泥添加和5%的赤泥添加导致土壤交换态Pb含量降低了44%和53%;土壤交换态Zn含量降低51%和56%。同时长喙田菁的生物产量也相应提高了53%和61%。 展开更多
关键词 赤泥 重金属吸收 交换状态
下载PDF
沙美特罗替卡松气雾剂在慢阻肺呼吸衰竭患者中的应用效果 被引量:3
7
作者 苏新根 蓝慧平 戴千金 《中外医学研究》 2022年第32期111-114,共4页
目的:探究及分析沙美特罗替卡松气雾剂在慢阻肺(COPD)呼吸衰竭患者中的应用效果。方法:将2019年7月-2022年1月龙岩市第二医院收治的94例慢阻肺呼吸衰竭患者根据随机数字表法分为对照组和观察组,各47例。对照组进行常规慢阻肺呼吸衰竭治... 目的:探究及分析沙美特罗替卡松气雾剂在慢阻肺(COPD)呼吸衰竭患者中的应用效果。方法:将2019年7月-2022年1月龙岩市第二医院收治的94例慢阻肺呼吸衰竭患者根据随机数字表法分为对照组和观察组,各47例。对照组进行常规慢阻肺呼吸衰竭治疗,观察组则在对照组的基础上加用沙美特罗替卡松气雾剂。比较两组的总有效率、不良反应发生率、治疗前后的血气分析指标[动脉血氧分压(PaO_(2))、动脉血二氧化碳分压(PaCO_(2))及pH值]及气体交换指标[肺换气指标最大吸气压(PImax)及最大呼气压(PEmax)、呼吸系统顺应性(Cst)及气道阻力(Raw)]。结果:观察组的治疗总有效率显著高于对照组,差异有统计学意义(P<0.05);两组的不良反应发生率比较,差异无统计学意义(P>0.05);治疗前两组的血气分析指标、肺换气指标、Cst及Raw比较,差异无统计学意义(P>0.05),治疗2、7 d后两组的血气分析指标、肺换气指标、Cst及Raw均显著改善,且观察组均显著优于对照组,差异有统计学意义(P<0.05)。结论:沙美特罗替卡松气雾剂在慢阻肺呼吸衰竭患者中的应用效果较好,且可显著改善患者的气体交换状态,应用价值相对较高。 展开更多
关键词 沙美特罗替卡松气雾剂 慢阻肺 呼吸衰竭 应用效果 气体交换状态
下载PDF
宽带智能网中IN-SSM模型的研究
8
作者 李炜 龙元香 +1 位作者 廖建新 陈俊亮 《高技术通讯》 EI CAS CSCD 2000年第1期32-35,共4页
提出了一种新的INSSM模型。它基于IN与BISDN综合方案,能有效地表示呼叫所使用的网络资源,同时也给BSCF提供一种视图,便于IN实现多方和多媒体业务。
关键词 宽带智能网 通信网 交换状态模型 IN-SSM模型
下载PDF
被切尔诺贝利核电站泄露污染的土壤中S_r^(90)的行为特征
9
作者 刘云成 《环境科学与管理》 CAS 1994年第2期20-21,共2页
众所周知,降落在土壤中的S<sub>r</sub><sup>90</sup>其可溶性化合物组份的移动性随着时间的推移而降低。(巴夫洛兹卡亚,1974;波果金,1971)。这个规律的产生有两个原因,一是核素向非交换状态转移;二是被吸附... 众所周知,降落在土壤中的S<sub>r</sub><sup>90</sup>其可溶性化合物组份的移动性随着时间的推移而降低。(巴夫洛兹卡亚,1974;波果金,1971)。这个规律的产生有两个原因,一是核素向非交换状态转移;二是被吸附的放射元素S<sub>r</sub><sup>90</sup>的健能的增加。 展开更多
关键词 切尔诺贝利核电站 污染的土壤 行为特征 移程 远区 近区 浸析 交换状态 液体介质 核素
下载PDF
Two-state energy model and experimental study of coal adsorb methane 被引量:2
10
作者 Zeng-Chao FENG Dong ZHAO Zhi-Xiang LIU Yan-Qi WANG Hong-Qiang GOU 《Journal of Coal Science & Engineering(China)》 2013年第4期488-492,共5页
There are two states of methane existing in coal, free methane and adsorptive methane. The two states of methane exchanged with each other which need the energy exchange with outside. It is released heat when methane ... There are two states of methane existing in coal, free methane and adsorptive methane. The two states of methane exchanged with each other which need the energy exchange with outside. It is released heat when methane adsorption on coal, instead of absorbed heat. According to the gas molecules Boltzmann energy distribution, is obtained the equilibrium equations of the two states of methane in coal, as well as the heat of adsorption equation when exchanged into each other. At the same time, high temperature experiments of methane adsorption on coal have been certificated to the theoretical model. At last the experimental results presented that: the two-state energy model could be accurately described the distribution of the two states of methane in the coal; the adsorption heat is related to the initial equilibrium state of methane adsorption; the adsorption heats are different with different coal ranks. 展开更多
关键词 two-state energy model adsorption heat chemical potential experimental study
下载PDF
Controlled Entanglement Swapping for Continuous Variables
11
作者 WU Dao-Hua DONG Ping +1 位作者 YANG Ming CAO Zhuo-Liang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第4期877-880,共4页
We propose a scheme for controlled entanglement swapping of continuous variable, where an EPR pair shared by two parties (Alice and Debbie) and a GHZ entangled state shared by three parties (Alice, Bob and Claire)... We propose a scheme for controlled entanglement swapping of continuous variable, where an EPR pair shared by two parties (Alice and Debbie) and a GHZ entangled state shared by three parties (Alice, Bob and Claire) are required. One optical beams of the EPR state will be entangled with the output mode displaced by Bob with the help of Claire. It is shown that the entanglement swapping can occur controlled by the third party (Claire) 展开更多
关键词 entanglement swapping continuous variable EPR pair GHZ entangled state
下载PDF
State Space Approach to Mass Exchange Network Synthesis 被引量:1
12
作者 马蔚钧 胡山鹰 +1 位作者 李有润 沈静珠 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第3期312-317,共6页
State space approach is an effective method to mass-exchange network (MEN) synthesis. By decomposing the network into two interactive parts, a distribution network and a process operator, the synthesis problem can be ... State space approach is an effective method to mass-exchange network (MEN) synthesis. By decomposing the network into two interactive parts, a distribution network and a process operator, the synthesis problem can be formulated into a mixed integer nonlinear programming (MINLP) model. In this article, a generalized state space model based on typical MEN is established and verified in two cases. A new asymmetrical operator and cost index are also adopted to speed up the solution process. The results demonstrate the efficiency of the proposed approach. 展开更多
关键词 mass exchange network state space SYNTHESIS OPTIMIZATION
下载PDF
Cellular Automata Model for a Specific Traffic Regime and 1/f Noise
13
作者 Reuben Thieberger 《Computer Technology and Application》 2015年第1期30-36,共7页
We examine the traffic lights regime to enable the fastest overall approach to a city for a specific case. The case involves a traffic light where one continues on the main road, into which additional cars are enterin... We examine the traffic lights regime to enable the fastest overall approach to a city for a specific case. The case involves a traffic light where one continues on the main road, into which additional cars are entering at the light. At this intersection an alternative route begins, which is longer but into which no additional cars are entering. To keep the total number of vehicles constant, we subtract on the main road far from the intersection, the same number of cars as were added at the intersection. In addition to checking different densities we check also the influence of changes in the number of cars which were added. We calculate the Fourier transform of the average on each traffic light cycles of the velocity on the main road and bypass. We obtained different results for different cases. All the cases can be written as 1/fa . 展开更多
关键词 Elementary cellular automata TRAFFIC pink noise.
下载PDF
试述邮政和邮市
14
作者 马联泓 《集邮博览》 2005年第1期21-22,共2页
邮票流通领域的一级市场和二级市场,说到底无非就是国家邮政发行部门和邮票的再次流通市场,其相互关系也就是现今统称的邮政和邮市的关系,这是中国特色邮市应运而生的产物,数十年来其间的情和缘、恩和怨交织演绎使得中国邮市曲折前行,... 邮票流通领域的一级市场和二级市场,说到底无非就是国家邮政发行部门和邮票的再次流通市场,其相互关系也就是现今统称的邮政和邮市的关系,这是中国特色邮市应运而生的产物,数十年来其间的情和缘、恩和怨交织演绎使得中国邮市曲折前行,最后或能途异归同。 (一) 自从邮票问世后不久,邮市就应运而生,其从萌芽交换状态开始到现代化规模经营历经了150年的轨迹,中国的邮市从19世纪80年代起就已现雏形,到了20世纪80年代起开始有了质的飞跃。在此期间,二级市场一直是一级市场的补充,是集邮爱好者调剂余缺, 展开更多
关键词 邮市 国家邮政 二级市场 中国特色 交换状态 相互关系 规模经营 发行部门 80年代 纪特邮票
原文传递
k元M序列的两种构造方法
15
作者 朱士信 《信息安全与通信保密》 1991年第1期12-20,共9页
M序列,又称为de Bruijn序列,是一类应用最广的移位寄存器序列。构造这类序列最常用的方法是合并由一个简单的非奇移位寄存器所生成的所有圈为一个全长圈,进而产生M序列。在本文中,通过对任意非奇反馈函数f(x_1,…,x_n)的状态图G_f进行赋... M序列,又称为de Bruijn序列,是一类应用最广的移位寄存器序列。构造这类序列最常用的方法是合并由一个简单的非奇移位寄存器所生成的所有圈为一个全长圈,进而产生M序列。在本文中,通过对任意非奇反馈函数f(x_1,…,x_n)的状态图G_f进行赋值,并构造一些特殊函数去实现G_f中的并圈过程,进而通过讨论这些特殊函数的运算,而给出M序列的直接构造方法。 展开更多
关键词 反馈函数 状态 状态转移交换 赋值函数 M序列
原文传递
Entanglement Swapping in the Presence of White and Color Noise
16
作者 Ivan S. Dotsenko R. Korobka 《Communications in Theoretical Physics》 SCIE CAS CSCD 2018年第2期143-153,共11页
The influence of white and color noise on the outcome of the entanglement swapping process is investigated in a four-qubit system. Critical degree of noise in initial state, that could destroy entanglement in a result... The influence of white and color noise on the outcome of the entanglement swapping process is investigated in a four-qubit system. Critical degree of noise in initial state, that could destroy entanglement in a result state is presented. The entanglement characteristics, such as concurrence, tangle, etc. are compared. Results could be helpful for experiments regarding entanglement swapping as conditions for initial quantum entangled states, to obtain entangled result state. 展开更多
关键词 ENTANGLEMENT entanglement swapping white noise ENTANGLEMENT
原文传递
Quantum Private Comparison of Equal Information Based on Highly Entangled Six-Qubit Genuine State 被引量:4
17
作者 纪兆旭 叶天语 《Communications in Theoretical Physics》 SCIE CAS CSCD 2016年第6期711-715,共5页
Using the highly entangled six-qubit genuine state we present a quantum private comparison(QPC)protocol, which enables two users to compare the equality of two bits of their secrets in every round comparison with the ... Using the highly entangled six-qubit genuine state we present a quantum private comparison(QPC)protocol, which enables two users to compare the equality of two bits of their secrets in every round comparison with the assistance of a semi-honest third party(TP). The proposed protocol needs neither unitary operations nor quantum entanglement swapping technology, both of which may consume expensive quantum devices. Single particle measurements and Bell-basis measurements, which are easy to implement with current technologies, are employed by two users and TP in the proposed protocol, respectively. The proposed protocol can withstand all kinds of outside attacks and participant attacks. Moreover, none of information about the two users' private secrets and the comparison result is leaked out to TP. 展开更多
关键词 quantum private comparison highly entangled six-qubit genuine state security
原文传递
Effects of material damping on flag flutter
18
作者 CHEN Ming JIA LaiBing +1 位作者 WANG SiYing YIN XieZhen 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第1期117-127,共11页
Complex interactions of plates with ambient fluid are common in daily lives,e.g.flags flapping in wind,aerofoils oscillating in flow.Recently,the feasibility to harvest energy using the flutter motion has been demonst... Complex interactions of plates with ambient fluid are common in daily lives,e.g.flags flapping in wind,aerofoils oscillating in flow.Recently,the feasibility to harvest energy using the flutter motion has been demonstrated.The objectives of this study are to systematically explore the effects of the material damping on flag flutter,and then to study the energy interchange between the fluid and the flag.In this study,a two-dimensional model was developed.Three dimensionless parameters govern the system,i.e.the mass ratio between the structure and the fluid,the dimensionless fluid velocity and the dimensionless material damping.Results show that the critical velocity increases with the increase of the material damping.The oscillation frequency of the flag decreases with the increase of the material damping,and the time-averaged energy dissipation rate initially increases and then decreases.The increase of the material damping causes the transition of the system from a higher frequency oscillating state to a lower frequency oscillating state,and from a chaotic state to a periodic state. 展开更多
关键词 AERODYNAMICS flow-structure interactions energy harvesting
原文传递
Feedback control for manipulating magnetization in spin-exchange optical pumping system
19
作者 Ke Zhang Jun Li +2 位作者 Min Jiang Nan Zhao XinHua Peng 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2018年第8期27-32,共6页
Control of magnetization plays an important role in the scientific and technological field of manipulating spin systems. In this work, we study the problem of manipulating nuclear magnetization in the spin-exchange op... Control of magnetization plays an important role in the scientific and technological field of manipulating spin systems. In this work, we study the problem of manipulating nuclear magnetization in the spin-exchange optical pumping system, including accelerating the recovery of nuclear polarization and fixing it on a specific desired state. A real-time feedback control strategy is exploited here. We have also done some numerical simulations, with the results clearly demonstrating the effectiveness of our method, that the nuclear magnetization is able to be driven towards the equilibrium state at a much faster speed and also can be stabilized to a target state. We expect that our feedback control method can find applications in gyro experiments. 展开更多
关键词 optical pumping feedback control nuclear magnetic resonance state stabilization
原文传递
On the validity of microscopic calculations of double-quantum-dot spin qubits based on Fock-Darwin states
20
作者 GuoXuan Chan Xin Wang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2018年第4期36-43,共8页
We consider two typical approximations that are used in the microscopic calculations of double-quantum dot spin qubits, namely,the Heitler-London(HL) and the Hund-Mulliken(HM) approximations, which use linear combinat... We consider two typical approximations that are used in the microscopic calculations of double-quantum dot spin qubits, namely,the Heitler-London(HL) and the Hund-Mulliken(HM) approximations, which use linear combinations of Fock-Darwin states to approximate the two-electron states under the double-well confinement potential. We compared these results to a case in which the solution to a one-dimensional Schr ¨odinger equation was exactly known and found that typical microscopic calculations based on Fock-Darwin states substantially underestimate the value of the exchange interaction, which is the key parameter that controls the quantum dot spin qubits. This underestimation originates from the lack of tunneling of Fock-Darwin states, which is accurate only in the case with a single potential well. Our results suggest that the accuracies of the current two-dimensional molecularorbit-theoretical calculations based on Fock-Darwin states should be revisited since underestimation could only deteriorate in dimensions that are higher than one. 展开更多
关键词 spin qubits double quantum dots exchange interaction
原文传递
上一页 1 2 下一页 到第
使用帮助 返回顶部