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1.
为在弹性光网络中实现最大化的备份频谱资源共享,提出了一种基于负载均衡的优先共享通路保护算法.在降低网络的阻塞率和保护开销时,综合考虑业务的传输距离、频谱资源利用率及链路状态等因素,建立整数线性规划模型确立优化目标,并提出启发式算法对路由和频谱分配联合优化选路,从而提供100%的单链路故障保护.仿真结果表明,与传统共享通路保护算法相比,所提算法在降低网络阻塞率的同时更有效地降低了保护开销,最大限度地实现备份频谱资源的共享.  相似文献   

2.
为解决WDM网状网的波带保护问题,提出一种基于多层OXC结构的动态专用波带保护(DDWP)算法.该算法以最小化可选路径对端口占用总数为第一优化目标,以路径对所经链路总数最小为第二优化目标.在不同负载动态业务下对DDWP算法进行了仿真研究.结果表明:DDWP算法有利于网络负载均衡和提高端口利用率,降低了全网阻塞率.  相似文献   

3.
针对WDM网状网中双链路失效问题,提出了一种共享链路保护算法,即SLP-2BP算法SLP-2BP 为每条业务请求计算1条最短路径作为工作通路,并为工作通路上的每条工作链路各计算2条链路分离, 且为最短的保护通路。通过计算机仿真,与现有算法即SLP-1BP算法进行了性能比较。仿真结果表明SLP-2BP算法不仅能有效地保护双链路失效1而且资源利用率和阻塞率性能都优于SLP-1BP算法。  相似文献   

4.
针对WDM网状网中双链路失效问题,提出了一种共享链路保护算法.即SLP-2BP算法。SLP-2BP为每条业务请求计算1条最短路径作为工作通路,并为工作通路上的每条工作链路各计算2条链路分离.且为最短的保护通路。通过计算机仿真,与现有算法即SLP-1BP算法进行了性能比较。仿真结果表明SLP-2BP算法不仅能有效地保护双链路失效,而且资源利用率和阻塞率性能都优于SLP-1BP算法。  相似文献   

5.
网络编码(network coding,NC)方法能够有效地提高路径保护技术的保护效率.但目前提出的基于网络编码的保护机制要求工作路径链路分离,限制了保护机制的性能和应用范围.为此提出一种基于网络编码的有共享链路的路径保护机制(shared-link network coding path protection,SNCPP).该机制将共享链路的端节点加入到保护路径源目的节点集中,采用改进的ASTAR算法建立经过节点集中所有节点的最短保护路径,并利用网络编码实现对有共享链路的路径进行保护.仿真表明所提出的机制在工作路径出现共享链路故障的情况下,能够对网络提供保护,并提高了保护效率.  相似文献   

6.
WDM疏导网络中的动态光路保护算法   总被引:1,自引:1,他引:0  
研究了WDM疏导网络的生存性问题,提出一种保护图模型来有效反映网络当前状态·基于该模型提出两种支持多粒度业务的动态专用光路保护算法:最小波长链路法(MWM)和最小收发器法(MTM)·MWM总是选用需要新占用WLE最少的路径建立连接,而MTM则尽量选择占用收发器对最少的路径建立连接·在不同负载的动态业务下对所提算法进行了仿真研究,结果表明,MTM所需仿真时间略低于MWM,而MWM具有更低的阻塞率和更高的业务通过率·  相似文献   

7.
WDM节能光网络中的抗毁保护算法研究   总被引:1,自引:1,他引:0  
针对波分复用(wavelength division multiplexing,WDM)光网络的节能需求,研究绿色网络解决方案,在光网络抗毁保护问题上提出绿色共享通路保护算法。该算法通过将工作通路和保护通路隔离在不同的光纤中,并将网络中的空闲资源和备份资源切换到睡眠模式,以实现光网络的节能。与传统共享通路保护算法的对比仿真表明,绿色共享通路保护算法能够有效提高网络功耗效率,并在低负载网络中取得网络总功耗和阻塞率性能的较好折中。  相似文献   

8.
在综合考虑光路径跳数、链路拥挤程度以及整个网络剩余资源对路由选择影响的基础上,提出了一种支持优先级的路由算法.该算法给较高优先级的链接请求安排较多的资源,从而降低高优先级的阻塞率,同时优化低优先级请求的阻塞率.计算机仿真结果表明,同传统的路由算法Fixed-Alternated Routing algorithm(FAR)相比,该算法在支持优先级路由的同时能有效降低网络各优先级的阻塞率.  相似文献   

9.
针对WDM光网络中为业务提供恢复时延保证造成网络开销过大的问题,提出一种带有时延感知的混合区分保护策略.该策略感知不同业务的时延要求从而划分业务优先级,然后充分利用P圈恢复速度快和共享通路保护资源利用率高的优点,分别对不同优先级业务进行混合区分保护,从而保证高低优先级业务不同的恢复时延要求;同时,采用遗传-整数线性规划算法选择覆盖全网的最优P圈,并通过链路代价函数均衡网络负载,从而进一步提升P圈的保护性能.仿真结果表明:所提区分保护策略具有较低的网络阻塞率,有效地提升了资源保护效率.  相似文献   

10.
为满足在网络生存性要求的同时提高网络资源的利用率,提出一种区分服务路径保护算法。在基于GMPLS(Generalized Mu lti-Protocol Label Sw itch ing)的DWDM(Dense W avelength D ivision Mu ltip lexing)网络中,当网络节点不具备波长变换能力且只配备有限对光收发器时,该算法针对网络中的高可靠性业务、中等可靠性业务及可抢占式业务对可靠性的不同要求,为其选择不同的保护方案。仿真结果表明:在3种类型业务等概率出现的情况下,可抢占式业务的平均阻塞率增加幅度最小,使带宽碎片造成的资源浪费减少了50%;高可靠性业务的共享程度比,随着连接请求的增加而降低;当网络达到动态平衡时,网络中各链路的总保护通路带宽与总工作通路带宽之比,在0.8~1之间;可抢占式业务所占带宽中属于保护通路的带宽与可抢占式业务所占带宽之比,随着网络负载的增大而增加缓慢。因此该算法在保证业务服务质量要求的同时达到了充分利用网络资源、平衡网络负载的目的。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

15.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

16.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

17.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

18.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

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