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1.
关于路由协议的一致性测试的一种形式方法   总被引:1,自引:1,他引:0  
为了一致性测试Internet网上的一个标准路信息协议(RIP协议),利用形式描述技术语言E-LOTOS对其进行了描述,然后把广西描述的E-LOTOS转换为GE-LOTOS,并在此产生了TTCN测试套。  相似文献   

2.
网络流量特征是分析和研究网络性能、规划网络建设的基础.网络流量研究中关键的问题是如何合成网络真实流量并进行分析,由于自相似模型能够更加真实地描述网络传输的特性,因此,本文通过生成自相似性的流量进行仿真研究,对自相似现象的成因进行了解释,提出将源端流量自相似性与网络传输的TCP协议相结合进行研究的方法,探讨了影响自相似流量的因素,了解了网络行为随参数变化的情况,对新一代网络的设计、控制、分析和管理具有实际意义.  相似文献   

3.
通过对多晶硅发射极晶体管(PET)的多晶硅及界面层导电特性的分析, 得到单晶发射区边界上电流密度与少子浓度之间的关系式,并以此为自洽的 边界条件,在单晶区数值求解一组描述晶体管电学特性的微分方程,得到晶 体管内部电势分布和载流子分布以及PET的端电流特性.  相似文献   

4.
赵伟 《科技信息》2014,(11):42-43
本文通过对网络流量数据用DYNATABLE算法进行冗余消除后,从重尾分布特性论证了冗余流量数据具有自相似性,用alpha稳定分布模型分析了冗余流量的重尾分布。实验结果表明,冗余流量具有自相似特性。  相似文献   

5.
以高级在轨系统(Advanced Orbit Systems,AOS)空间数据链路协议为基础,建立了CCSDS AOS协议信源模型,对比分析了自相似流量模型下先来先服务(first-come-first-served,FCFS)和时间片轮询(round-robin,RR)虚拟信道调度算法的性能.根据网络流量具有自相似性的特点,采用时间间隔服从正态分布的分形布朗运动流量模型描述AOS虚拟信道中数据流的自相似特性,并使用快速傅立叶变换方法生成了不同自相似系数的分形布朗运动流量,获取了数据包的到达时间、到达时间间隔和数量;之后通过仿真实验对比了FCFS和RR两种虚拟信道(VC)调度算法的时延和积压性能.实验结果表明,当到达数据量较小时,两种调度算法性能相当;当到达数据量较大时,RR调度算法的时延和积压性能明显优于FCFS调度算法.研究结果可为AOS虚拟信道调度算法的研究和设计提供参考.  相似文献   

6.
应用小波变换,精确地刻画网络流量的自相似特性,应用Mallat算法模拟网络流量在此基础上,分析了局域网和广域网的网络流量特性.  相似文献   

7.
自相似网络流量预测研究   总被引:2,自引:0,他引:2  
研究发现,网络流量自相似特性具有普遍性,且不随缓冲、交换、传输和延迟而改变,网络流量预测必须考虑这种自相似特性.本文从自相似网络流量的多个方面对现有研究成果进行了分析,从网络自相似的模型、参数估计、性能预测等多个方面对网络自相似流量预测研究进展进行了总结,并提出了一种基于测量的流量自相似等价带宽预测算法.分析表明:该算法能有效地减少计算量和降低实现复杂度.  相似文献   

8.
利用WKL-3型可控式消煮炉测定土壤全氮的最佳时间研究刘东强,韩志卿,张电学(河北农业技术师范学院农学系,昌黎,066600)STUDYONTHEOPTIMUMTIMEFORDETERMININGTOTALNITROGENINSOILSWITHTHE...  相似文献   

9.
分析了实现ATM网中话音通信的各项技术的特点,指出了宽带终端(B-TE)实现话音通信应具有的功能。对B-TE中适配层的选择、信元打包策略和定时信号的传输方案进行了分析与讨论,建立了B-TE话音通信功能模型。讨论了网络互通单元(IWU)的信令传输方式,交换虚通道(SVC)或永久虚通道(PVC)两种ATM网连接IWU的方案,分析建立了IWU的协议模型和功能结构模型,分析表明采用PVC可以避免在网络中设  相似文献   

10.
传统的业务模型大多基于Poisson模型或其改进形式,假定业务突发长度显负指数分布,近期真实网络流量分析表明很多信息源会产生在多时间尺度下具有自相似特性的信息流,该性质显地影响宽带网的流量控制及其排队分析,本综合地介绍了自相似的数学描述和性质,五种自相似业务流的产生方法,其中有两种给出了具体的算法,还总结了几种主要的估计Hurst参数的方法。  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.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

15.
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   

16.
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   

17.
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   

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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