一种适合长距离带状无线传感器网络的路由协议

针对长距离带状无线传感器网络的能耗不均、易出现“热区”等问题,本文提出一种适合长距离带状无线传感器网络拓扑结构的能量高效的路由协议ERPLDB。ERPLDB协议通过网络能耗模型中的能量消耗公式计算出各个簇的网络节点平均能耗, 并使各个簇内的网络节点平均能耗近似相等来进行非均匀分簇,使越靠近Sink节点的簇规模越小,从而有更多的能量转发远程簇传输过来的数据,尽量减少“热区”问题的出现。仿真结果表明,本文提出的ERPLDB协议能均衡长距离带状网络的能量消耗、有效延长网络的生命周期。     

一种节能的分簇路由算法研究

由于无线传感器网络具有能量有限等特点,如何高效的使用能源已成为人们研究的热点.结合已有的研究,提出了一种基于节能的分簇路由算法.节点分成簇间与簇内两级拓扑结构,簇内节点通过在最后一个数据包中“捎带”自身剩余能量信息参与下一轮簇头节点的选举,簇头节点之间形成网状拓扑结构,并维持一张由邻居节点梯度、距离及剩余能量值组成的权值路由表,通过尽量选择权值最小的路径进行数据的传输,实现节能、均衡能量消耗、延长网络生命周期的目的.     

无线传感器网络启发式分簇拓扑控制方法研究

传统启发式分簇拓扑控制方法通信开销大、负载均衡性差,忽略剩余节点能量,导致拓扑结构连通性和骨干网健壮性差,无线传感网络生命周期短。为此,提出一种新的无线传感器网络启发式分簇拓扑控制方法。给出无线传感网络模型。利用粒子完成分簇,对簇内负载与簇间负载进行分析,保证负载均衡性。引入一种描述节点间能耗及鲁棒性的行向量,以全面分析骨干节点通信开销与剩余能量对簇头挑选的影响。将最小生成树作为网络的基础结构,引入表示网络连接状态的列向量,以描述网络通信开销情况,获取目标函数。通过粒子群法求最优解,实现簇头选择。通过簇头组成骨干网,实现无线传感器网络拓扑控制。实验结果表明,所提方法能够保证拓扑结构的连通性与骨干网健壮性,延长网络生命周期。     

基于能耗预测的WSN单跳路由分簇算法研究

针对分簇是实现WSN拓扑控制、节能、网络寿命的延长有效方式之一,基于LEACH的协议结构和能量消耗模型,提出了一种基于能耗预测的分布式单跳路由分簇算法（FED:forecasted energy dissipation）,定义了由其能耗预测指数和剩余能量比例系数动态地确定的节点竞争簇首门限,给出了基于时间优先、能量优先和比例优先竞争策略的FED算法。节点竞争簇首的参数选择与网络规模无关,且最大时间复杂度为O(1)。对时间优先、能量优先和比例优先竞争策略的FED算法的仿真研究结果表明：与LEACH和EECS算法相比,基于能量优先和比例优先的分簇算法较大地延长了网络寿命和提高了网络能量的利用性能。     

无线传感器网络启发式分簇拓扑控制方法

传统启发式分簇拓扑控制方法通信开销大、负载均衡性差,忽略剩余节点能量,导致拓扑结构连通性和骨干网健壮性差,无线传感网络生命周期短。为此,提出一种新的无线传感器网络启发式分簇拓扑控制方法。给出无线传感网络模型。利用粒子完成分簇,对簇内负载与簇间负载进行分析,保证负载均衡性。引入一种描述节点间能耗及鲁棒性的行向量,以全面分析骨干节点通信开销与剩余能量对簇头挑选的影响。将最小生成树作为网络的基础结构,引入表示网络连接状态的列向量,以描述网络通信开销情况,获取目标函数。通过粒子群法求最优解,实现簇头选择。通过簇头组成骨干网,实现无线传感器网络拓扑控制。实验结果表明,所提方法能够保证拓扑结构的连通性与骨干网健壮性,延长网络生命周期。     

一种基于能量和距离的多级能量异构传感器网络路由算法

为了能有效地利用节点能量的异构性,降低网络能耗、延长网络稳定周期,提出了一种同时考虑节点剩余能量和节点至基站距离的多级能量异构无线传感器网络的分簇路由算法.在节点簇间综合考虑簇头剩余能量及其与基站的通信能耗,以选择合适的下一跳路由节点.仿真结果表明,该算法可以有效地均衡网络能量消耗,延长网络稳定周期.该路由算法在维持节点存活个数、降低网络能量消耗及增加网络数据传输吞吐量等指标方面优于几种常见传感器网络路由算法,表明在综合考虑能量和距离等因素后能够获得比单一考虑能量或者距离的算法更优的运行结果.     

基于双簇头无线传感器网络分簇算法的研究

针对无线传感器网络分簇协议中簇头及附近节点能量消耗不均衡的问题,提出了一种基于双簇头的无线传感器网络分簇路由算法。该算法利用双簇头的网络模型来解决节点侦测信道消耗能量的问题;构造了适应值函数和能量消耗函数用于选择和优化簇头,提高网络能量消耗的均衡性,降低网络能耗。实验结果证明了该算法的有效性。     

一种能量高效的无线传感器网络分簇路由算法

分析了无线传感器网络的分簇路由算法,针对现有算法存在的热点问题,提出一种基于分簇思想的能量高效路由算法.采用簇首轮转及局部竞争优化节点簇内通信的能量消耗,采用粒子群优化算法均优化簇首节点的簇间通信负载和能量消耗,从而延长网络的生命期.仿真结果表明,该算法能够有效提高无线传感器网络生存期以及节点与网络的能量利用率.     

基于移动Agent的无线传感网络拓扑控制策略

针对目前无线传感网络拓扑控制算法中未考虑节点能耗问题,提出基于移动Agent的无线传感网络拓扑控制策略,并采用移动Agent洪泛获取网络拓扑信息的方法.该方法由sink节点洪泛拓扑发现Agent进行拓扑发现,由拓扑汇报Agent将拓扑信息传送至sink节点,并根据节点剩余能量动态选择簇头.仿真结果表明,该方法簇头分布均匀合理,能够有效节约网络能耗.     

基于最优簇头数的环形无线传感器网络分簇算法

基于无线传感器网络中每个环能量消耗最小原则, 提出一种基于最优簇头数的环形无线传感器网络分簇算法. 首先计算出网络中每个环的最优簇头数, 然后在最优簇头数的基础上, 将网络划分为若干不同大小的簇, 最后在选择簇头时, 考虑了每个环的最优簇头数与相应环中节点数目的比值、 节点的剩余能量以及簇成员节点到簇头节点的最短距离与簇头节点到基站距离的关系. 解决了无线传感器网络簇内节点通信能量消耗过多的问题, 均衡了网络节点的能耗. 仿真结果表明, 该算法提高了网络能效和扩展性, 平衡了网络能耗, 延长了网络的生命周期.     

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-