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1.
为减轻节点不相交多路径路由负载和解决路径间的耦合问题,提出了一种基于定向天线的最小能量节点不相交多路径自组网路由算法(RMENDMRDA).初始时该算法应用优化波宽选择算法确定定向天线的最小扇形覆盖区域,从而节省能量消耗,在选择累计能量最小的节点不相交多路径时采用链路可靠性选择算法,以满足链路的可靠性要求.分析及模拟结果表明,该算法路由负载更小、路由发现频率更低.与源传输能量选择路由算法和节点不相交多路径路由算法相比,RMENDMRDA的数据包投递率提高了18%,路由负载降低了24%,节省能量约8%.  相似文献   

2.
针对无线传感器网络能量多路径路由算法存在的缺陷及其原因,提出一种基于动态优先级的能量多路径路由算法。该路由算法以节点距汇聚节点的路径跳数值替代路径能耗代价确定其优先级,并在数据传输过程中根据节点的能量消耗不断调整优先级,降低了算法的复杂度,避免了周期性路由维护所带来的时间与能量损失。仿真结果表明,该算法能有效降低和平衡各节点的能耗,延长整个网络的生存周期。  相似文献   

3.
Ad-Hoc网络中一种可靠的节点不相交多路径路由算法   总被引:2,自引:0,他引:2  
提出了一种可靠的节点不相交多路径路由算法(RNDMRA). 结合预测模型和能量模型,利用网格中节点的地理信息,有效减少路由发现泛洪的频率. 同时为了选择与最短路径相似的稳定多路由,RNDMRA应用相似性因子选择相似的稳定节点不相交多路径路由. 模拟结果显示,与AODV和NDMR相比,RNDMRA有更高的投递率,更小的路由延迟和路由负载.  相似文献   

4.
针对移动自组织网络的网络拥塞问题,基于能量感知技术并结合负载均衡和拥塞控制方法,提出了一种能量感知多路径负载均衡路由算法。该算法利用能量感知选择满足条件的节点作为路由节点,建立多条连接源节点和目的节点的有效路径;同时分析路径的跳数、节点缓冲区的占用情况,从有效路径中选出用于传输的最优路径;然后对最优路径上的节点和路径的负载情况进行建模分析,当节点能量、节点负载、路径负载到达设定的阀值,就将最优路径上的流量分流到其它路径。利用NS2仿真软件,在不同的场景下对该算法以及QMRB、SMORT进行仿真测试。仿真结果显示:提出的算法与其它路由算法相比将网络性能提升了近20%,起到了均衡负载的作用,能有效地解决网络拥塞问题。  相似文献   

5.
移动视频技术的广泛应用给移动自组网络的服务质量带来很大的挑战.相较于传统的单路径路由算法,基于多约束的多路径路由算法具有更强的可靠性和适用性.多约束条件路由问题是一个NP困难问题,如何高效求出优化解成为该技术的关键.针对移动自组网络在视频传输过程中存在的链路拥塞及能量损耗问题,设计一种基于鲸鱼优化算法的多路径路由发现算法,有效求解满足多约束条件的多路由路径,提高了移动自组网络的性能和服务质量.  相似文献   

6.
在能量异构传感器网络中,由于节点能量在一定范围内随机分布,平衡能量消耗和延长网络寿命成为此类算法的一个重要挑战.针对该问题,提出了一种基于蚁群算法的异构传感器网络路由算法.算法通过改善网络拓扑结构、优先使用剩余能量较大的节点、构建异构传感器网络多路径路由来实现.模拟实验表明:与传统路由算法(DADC)相比,算法能更好地平衡能量消耗,延长网络寿命.  相似文献   

7.
基于簇的路由协议是无线传感器网络的研究热点,本文针对现有的簇间路由协议没有考虑网络负载的均衡,提出一种高效节能的无线传感器网络簇间多路径路由协议。该协议基于簇头节点到汇聚节点的最小跳数生成从簇头节点到汇聚节点的多条路径,根据簇节点的剩余能量和负载将数据通信均匀分布在不同的路径上,从而达到簇头节点间的负载均衡。仿真实验结果表明,该路由协议能有效地均衡网络负载,节省簇头节点能量,从而延长网络的生存时间。  相似文献   

8.
本文针对无线传感器网络提出了一种实时的能量均衡多路径路由算法RTEB-MR(Real-Time Energy-Balancing Multi-Path Routing)。RTEB-MR是由源节点发起的路由协议,采用受限洪泛传播路由请求消息来建立路由,减少了采用普通洪泛所带来的较大的能量消耗,在保证实时传输的情况下,从多条路由路径中选择能量最大的进行路由。仿真显示,与其它算法比较,RTEB-MR算法在节能及延长网络生命周期等方面有较好的性能。  相似文献   

9.
针对无线传感器网络路由存在能量空洞的问题,提出一种分布式非均匀分簇路由算法.该算法在选择候选簇首时引入位置因子和平均能量因子来平衡全网节点的剩余能量;网络运行过程中,候选簇首通过自适应校正其竞争半径进行非均匀分簇.采用基于能量和距离的能耗函数入簇机制以均衡全网能量消耗,利用多跳动态路由以避免稳定传输阶段转发节点因能耗过大而快速死亡.通过构建网络模型,采用Matlab对文中算法和UCR算法进行仿真分析比较.仿真结果表明:文中算法簇首消耗能量的方差波动不大较稳定,相比UCR更好地均衡了簇首能量消耗,并且能够有效避免能量空洞,均衡网络负载,网络生命周期较UCR算法提高了约34%.  相似文献   

10.
基于量子遗传算法的无线传感网络路由优化   总被引:1,自引:0,他引:1  
考虑到无线传感网络(WSN)传感器节点的能量有限性,分析了WSN的网络模型和能量模型,提出一种基于改进量子遗传算法的路由优化算法.利用复杂连续函数测试,验证了算法的性能和可行性.经仿真分析,证明该算法应用于WSN路由优化问题时,能更快速和更稳定地求解最小能量代价的数据传输路径,从而减少WSN传感器节点的能量消耗,延长整个WSN网络的使用寿命.  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.
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   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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   

16.
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   

17.
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   

18.
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   

19.
20.
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   

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