The systematical and scalable frameworks were provided for estimating the blocking probabilities under asynchronous traffic in optical burst switching(OBS) nodes with limited wavelength conversion capability(LWCC) . T...The systematical and scalable frameworks were provided for estimating the blocking probabilities under asynchronous traffic in optical burst switching(OBS) nodes with limited wavelength conversion capability(LWCC) . The relevant system architectures of limited range and limited number of wavelength converters(WCs) deployed by a share-per-fiber(SPF) mode were developed,and the novel theoretical analysis of node blocking probability was derived by combining the calculation of discouraged arrival rate in a birth-death process and two-dimensional Markov chain model of SPF. The simulation results on single node performance verify the accuracy and effectiveness of the analysis models. Under most scenarios,it is difficult to distinguish the plots generated by the analysis and simulation. As the conversion degree increases,the accuracy of the analysis model worsens slightly. However,the utmost error on burst loss probability is far less than one order of magnitude and hence,still allows for an accurate estimate. Some results are of actual significance to the construction of next-generation commercial OBS backbones.展开更多
The issue of burst losses imposes a constraint on the development of Optical Burst Switching （OBS） networks. Heavy burst losses strongly affect the Quality of Service （QoS） intended by end users. This article pres...The issue of burst losses imposes a constraint on the development of Optical Burst Switching （OBS） networks. Heavy burst losses strongly affect the Quality of Service （QoS） intended by end users. This article presents a QoS aware Routing and Wavelength Allocation （RWA） technique for burst switching in OBS networks. The RWA problem is modeled as a bi-objective Integer Linear Programming （ILP） problem, where objective functions are based on minimizing the number of wavelengths used and the number of hops traversed to fulfill the burst transmission requests for a given set of node pairs. The ILP model is solved using a novel approach based on a Differential Evolution （DE） algorithm. Analytical results show that the DE algorithm provides a better performance compared to shortest path routing, which is a widely accepted routing strategy for OBS networks.展开更多
目的探讨听力损失儿童短纯音听性脑干反应(tbABR)与行为测听(behavioral audiometry,BA)的相关性。方法回顾性分析91例听力损失儿童tbABR和BA测试结果,根据各频率tbABR最大刺激100 dB nHL有无反应,将91例(163耳)听力损失儿童分为有反应...目的探讨听力损失儿童短纯音听性脑干反应(tbABR)与行为测听(behavioral audiometry,BA)的相关性。方法回顾性分析91例听力损失儿童tbABR和BA测试结果,根据各频率tbABR最大刺激100 dB nHL有无反应,将91例(163耳)听力损失儿童分为有反应组(1个或以上频率有反应100耳)、无反应组(4个频率均无反应63耳),分析有反应组500、1000、2000和4000 Hz四个频率tbABR阈值和BA阈值的相关性和差异,并分析两阈值之差的可能影响因素;无反应组则统计各频率BA阈值。结果tbABR有反应耳500、1000、2000和4000 Hz四个频率的tbABR阈值与BA阈值的相关系数分别为0.85、0.90、0.93、0.88,两阈值之差分别为6.9±13.0、2.4±10.2、-0.9±9.5、4.1±12.3 dB,其中BA阈值是两阈值之差的有效影响因素,随着听力损失程度加重,阈值之差减小;四个频率tbABR均无反应的63耳,其BA结果提示均为极重度聋。结论tbABR阈值与BA阈值的相关性很好,可以用于预测BA阈值,但应考虑听力损失程度的影响。展开更多
基金Project(60632010) supported by the National Natural Science Foundation of China
文摘The systematical and scalable frameworks were provided for estimating the blocking probabilities under asynchronous traffic in optical burst switching(OBS) nodes with limited wavelength conversion capability(LWCC) . The relevant system architectures of limited range and limited number of wavelength converters(WCs) deployed by a share-per-fiber(SPF) mode were developed,and the novel theoretical analysis of node blocking probability was derived by combining the calculation of discouraged arrival rate in a birth-death process and two-dimensional Markov chain model of SPF. The simulation results on single node performance verify the accuracy and effectiveness of the analysis models. Under most scenarios,it is difficult to distinguish the plots generated by the analysis and simulation. As the conversion degree increases,the accuracy of the analysis model worsens slightly. However,the utmost error on burst loss probability is far less than one order of magnitude and hence,still allows for an accurate estimate. Some results are of actual significance to the construction of next-generation commercial OBS backbones.
文摘The issue of burst losses imposes a constraint on the development of Optical Burst Switching （OBS） networks. Heavy burst losses strongly affect the Quality of Service （QoS） intended by end users. This article presents a QoS aware Routing and Wavelength Allocation （RWA） technique for burst switching in OBS networks. The RWA problem is modeled as a bi-objective Integer Linear Programming （ILP） problem, where objective functions are based on minimizing the number of wavelengths used and the number of hops traversed to fulfill the burst transmission requests for a given set of node pairs. The ILP model is solved using a novel approach based on a Differential Evolution （DE） algorithm. Analytical results show that the DE algorithm provides a better performance compared to shortest path routing, which is a widely accepted routing strategy for OBS networks.
