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1.
通过对各种网络系统及其协议体系的研究,提出了一种自定义协议的制定方法. 该方法定义了一种通用的协议结构,保证协议体系条理清晰,方便管理. 该方法的协议定义思想,使被定义协议具有可拓展性和可复用性. 通过一个示例,详细说明了该自定义协议结构的各个组成部分,以及协议中主要字段的含义和用法.  相似文献   

2.
路由协议是移动自组网领域研究的热点与难点,其中按需路由协议AODV被广泛研究与应用.本文针对AODV协议只保存单一路径的不足,提出一种改进的AODV路由协议,通过仿真实验与分析,证明改进的AODV路由协议有效地增强了移动自组网的性能.  相似文献   

3.
首先概述当今常用的协议模型技术;然后重点剖析基于FSM、Petri网和TL模型的协议形式化描述与验证技术的研究现状;最后介绍了一种最新协议描述技术-Z协议技术。此外,本文还对这四种协议形式化技术各自的特点发表了作者的观点。  相似文献   

4.
密钥交换协议JFK的分析与研究   总被引:2,自引:0,他引:2  
快速密钥交换(JFK)协议是一种新的密钥交换协议,它的安全性引起了人们的重视。文中通过使用BAN类逻辑方法针对其安全目标进行了分析与研究。首先简介了JFK协议的两种形式和报文交互的工作原理,在此基础上指出了它所达到的安全目标,然后介绍了BAN类逻辑方法的符号语义说明和逻辑规则,并通过使用它对JFK协议中一种具体形式JFKr的安全性进行了分析证明。得出了JFK协议满足密钥交换协议的基本安全需求的结论。  相似文献   

5.
在嵌入式系统中,设备多且分散,使用传统传输协议不能满足实时及可靠性的要求.本文分析研究了一种更适合嵌入式可靠传输的协议——可靠用户数据报协议RUDP,着重将该协议与传统协议在传输速率及可靠性方面进行了测试和比较.  相似文献   

6.
串空间理论自提出后成为了一种重要的协议形式化分析方法.由于理想结构的特殊性,使得关于消息代数上的理想以及诚实的概念被引入到分析协议的保密性.对理想在分析其他协议安全性方面作了进一步的研究.其研究主要集中在利用理想分析协议的认证性应用、零知识性、前向安全性以及如何抵抗猜测攻击上.  相似文献   

7.
概述了Cache的一致性问题及目前的研究情况,并在现有的Cache一致性协议的基础上,提出了一种改进的Cache一致性协议以及该协议所应用的单芯片多处理器体系结构。  相似文献   

8.
IPv4协议最终将被IPv6协议所取代,但是目前基于IPv6协议的应用程序的研究还处于初期阶段.通过研究FTP协议对IPv6协议的支持情况,提出了一种基于IPv6协议的FTP服务器实现方案,并实现之.通过对设计出来的FTP服务器进行了测试,同时利用Sniffer软件进行了抓包分析.结果显示该FTP服务器完全支持IPv6协议,并能实现用户登陆、密码验证、文件列表传送、文件下载、文件上传、文件删除等功能.  相似文献   

9.
为两段提交协议构造了Petri网模型,并在此模型的基础上运用Petri网理论的方法对两段提交协议进行了分析.为进一步研究和改进两段提交协议提供了一种新的思路.  相似文献   

10.
一种路由协议测试框架研究   总被引:9,自引:0,他引:9  
为了确保 Internet通信子网的正确性和可靠性 ,提出了一种用于路由协议测试的测试框架。由于传统的测试分类不适用于路由协议 ,所以路由协议应作为一个整体来测试。在分析了路由协议与端系统协议的异同之后 ,提出了一种适用于路由协议测试的 Dip- in抽象测试法 ,并推荐并发TTCN作为测试集描述方法。利用上述测试理论 ,设计实现了可实际应用的分布式路由协议测试系统。该文的研究是对Internet中的核心技术——路由协议测试的一种新探索 ,在我国路由器技术国产化的过程中意义重大  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 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   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
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   

15.
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   

16.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
19.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

20.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

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