传感器网络基于邻居信息量化的能量平衡路由

针对地理位置路由中数据包的平均传输能耗随时间推移急剧增加的问题,设计并实现了一种基于两跳邻居信息量化的能量平衡路由协议(TNEB).节点通过Hello报文获得两跳范围内的邻居节点信息,TNEB根据两跳邻居信息确定一个贪婪转发候选节点集合.依据邻居节点的数据流拥塞度和能量平衡度,从候选节点集合中选择最佳的邻居节点完成数据包的转发.测试结果表明,在平均邻居节点数为15的网络拓扑上,TNEB算法的平均能耗比Greedy-2和GPSR算法分别降低了26.7％和48.8％,端到端延迟分别减少了19.9％和31.8％.     

基于机会转发原理改进的GPSR算法

针对现有GPSR协议中边界节点消耗大、丢包严重以及在遇到路由空洞时路由效率低下的问题,提出一种基于机会转发的改进路由:O-GPSR。它使用距离、方向和邻居节点密度三个参数来计算转发决策节点传输范围内各邻居节点的判决度量值,依据度量值选择下一跳转发节点。仿真结果表明,O-GPSR能够降低端到端时延、减少路由负载、增加投包率,有效地提高了路由效率。     

一种基于地理信息的改进GPSR算法

针对车载自组织网络（VANET）中基于地理信息的GPSR协议在转发数据包时通信链路不够稳定的问题,文章提出了一种改进的路由算法——GPSR-S算法。该算法根据任一车辆节点在不同时刻的地理坐标,分别计算出它们的运行速度和运动方向,再通过速度和方向计算节点间通信链路的维持时间,兼顾链路稳定性和距离,选出可靠的下一跳。利用网络仿真平台NS-3对GPSR、GPSR-S进行仿真,结果表明,GPSR-S算法在数据包传递率、端到端时延方面的性能得到了提升,更适合在车载自组网中应用。     

VANET场景下的GPSR-R路由算法

路由选择是实现VANET的关键技术之一,没有合适而高效的路由选择算法,VANET就无法工作。由于路由在长距离通信时多跳易断裂,通信链路只需满足通信需求即可。文章对GPSR路由协议进行了改进,提出了VANET场景下的GPSR路由算法:GPSR-R。GPSR-R根据移动节点间链路建立的网络需求进行综合考虑,充分利用不稳定但满足需求的路由完成信息的传递。分析结果表明,GPSR-R在数据包传递率、丢包率方面优于GPSR和GPSR-AD。     

城市环境下的一种车辆自组织网络机会路由协议

车辆自组织网络(vehicular ad-hoc networks,VANET)的拓扑结构具有高动态性,设计适应其高速变化的路由协议具有很大挑战性。提出采用机会转发方式的地理位置路由协议,将每次转发的单一目标节点改进为一个集合,以降低高速变化的拓扑导致的节点接收数据失败的概率。提出了一种新颖的转发集构成方案,改进了传统的由数据包携带转发集的做法,将转发集合的计算和确定分布到每个接收节点,在很大程度上减少了路由控制信息开销。提出了一种动态的转发节点选择机制,并引入了对实时交通状况的考虑,在一定程度上依据实时交通密度选择转发路径,能有效应对车辆自组织网络连接不稳定性。仿真结果表明,所提出的路由协议在包投递成功率、端到端传输时延和归一化路由开销等方面都取得了较好的路由性能。     

适用于语音业务的MANET机会路由机制

传统路由机制需要在源和目的节点之间预先建立端到端路径,当链路质量较差时,频繁地建立路径会影响业务的服务质量。为支持实时语音业务,提出一种机会路由机制,该机制并不预先建立连接,而利用多个路由请求和路由应答消息建立转发列表,表中的节点利用与其他节点的相遇机会对数据包进行转发,并根据转发节点的优先级对转发数据包的数量进行限制。仿真结果表明:机会路由机制能够减小语音业务的端到端时延,提高分组投递率,可以在不稳定的信道为语音业务提供服务质量保证。     

Ad Hoc网络中基于AODV的拥塞适应路由协议

该文提出邻居拥塞表概念,利用旁路、邻居拥塞表、hello消息和下一绿色节点请求技术,对自组网按需距离矢量(AODV)协议进行改进,提出自组网拥塞适应按需距离矢量(CA-AODV)路由协议.在CA-AODV协议中,主节点利用邻居拥塞表,能在第一时间感知网络拥塞.当拥塞发生时,拥塞节点的上一节点能按需建立绕过拥塞节点的旁路,当数据流到达已建立旁路的节点时,被按比例分流在主路由和旁路上,实现了拥塞适应功能.仿真结果显示,与AODV相比,CA-AODV协议的平均端到端延迟更短、数据包递交率更高、规格化路由开销更少.     

传感器网络汇聚数据包路由协议

针对移动目标跟踪应用对传感器网络路由协议的性能要求,提出了一种汇聚数据包路由协议,用于由目标区域到sink节点的汇聚数据包路由.协议采取基于sink节点的贪婪转发策略,通过减少通信跳数,减少了数据包从目标节点到sink节点的端到端传输时延;协议以节点能量和距离的综合函数作为转发代价,使其具有较高的能量效率;只要求节点维护自身状态信息,具有较好的可扩展性.仿真实验表明,协议能够满足目标跟踪应用对传感器网络路由协议的性能要求.     

一种两跳自适应信标航空贪婪周边无状态路由（GPSR)协议

结合民用航空环境和自由飞行应用背景,针对贪婪周边无状态路由（greedy perimeter stateless routing, GPSR)固定的信标周期无法适应高度动态的移动自组网,邻居表维护准确度和控制开销无法自适应调节的问题, 提出了一种基于两跳自适应信标交换算法的GPSR改进协议GPSR-TA( GPSR-two hops adaptive beacon)。NS2的仿真结果表明,在二维场景下,使用改进邻居发现机制的GPSR-TA能使节点自适应地感知周围邻居的分布,并在保证邻居发现精度的前提下自适应调整控制开销,较GPSR更适用于高动态民用航空环境。     

基于节点梯度的车辆网络(VANET)路由算法

由于节点的高速移动以及拓扑结构的动态性,传统路由协议不能有效地适用于车载自组织网络。为此,利用梯度理论,提出了一种基于节点梯度的路由协议(node gradient routing,NGR)。该协议充分利用节点的特性,计算节点的梯度值,并将梯度值最大的节点作为下一跳的转发节点。在计算梯度值时,考虑到转发节点与目标节点的距离、节点的移动方向、节点的负荷以及节点的周围密度等因素。仿真数据表明提出的NGR具有良好的路由性能,与典型地理路由协议GPSR和Ad Hoc路由协议AODV相比,所提出来的算法的数据包丢包率、端到端传输时延、数据吞吐量方面性能有较大的改善。     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

A computer generator for randomly layered structures

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

An Index mechanism for multi-scale view in spatial databases

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.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-