无线传感器网络多重覆盖成簇算法

在传统的无线传感器网络簇生成算法中,簇首的选择没有考虑其剩余能量,也没有分析簇首为簇内节点提供数据转发服务存在服务失败的问题,为此提出了一个新的无线传感器网络簇生成算法———多重覆盖成簇算法,该算法以待选簇首节点的剩余能量和节点初始能量的比值作为簇首服务的失败率,在此基础上算法选择的簇首通过对关键节点进行多重覆盖,以保障关键节点数据的可靠传输.最后,通过仿真实验验证了算法的有效性和正确性.     

基于能量均衡的无线传感网络路由算法

有效的簇首选择策略可提高无线传感器网络（WSN）的负载均衡和簇首均匀分布程度,延长网络生存时间.现有算法在选取簇首时未充分考虑节点剩余能量和能耗速率,导致负载不均衡,部分节点因耗能过度而提前消亡.为此,本文提出一种基于能量均衡的WSN路由算法,该算法使用节点剩余能量、能量消耗速度、与Sink节点的距离作为簇首选择参数,并通过回退机制实现节点回退等待时间的自适应调整,从而保证高能量节点有更高机率成为簇首.实验表明,该算法可有效避免“热区”的出现,延长网络寿命     

改进LEACH的传感器网络分簇路由算法

针对当前无线传感器网络分簇路由算法存在的节点能耗不平均、 节点过早死亡等缺陷, 提出一种改进低功耗自适应分簇(LEACH)的无线传感器网络路由算法. 首先针对无线传感器节点过早死亡的问题, 引入簇半径动态确定方式, 将整个无线传感器网络划分为多个不均匀的簇; 然后考虑簇首能量消耗过快的问题, 结合簇首所在位置和节点剩余能量选择每轮中的簇首; 最后改进数据传输机制保证节点能量消耗均衡, 并在MATLAB 2014平台上对无线传感器网络分簇路由算法的性能进行测试. 测试结果表明, 改进LEACH算法较好地解决了节点过早死亡的难题, 延长了无线传感器网络的寿命, 平衡了各节点能量消耗, 整个无线传感器网络的性能显著优于其他对比算法.     

考虑剩余能量和通信代价的传感器网络路由算法

路由能耗直接影响无线传感器的寿命,针对当前无线传感器网络路由算法存在的能量利用率低、严重不均衡等难题,设计了一种基于考虑剩余能量和通信代价的传感器网络路由算法。该算法首先从簇首选择问题入手,全面考虑所有传感器节点剩余能量进行簇首选择和竞争,选择最优传感器节点作为簇首,防止剩余能量最少的传感器节点成为簇首;然后选择通信代价小、剩余能量多的传感器作为通信的中继节点,均衡各节点的能耗,最后采用仿真工具NS2对路由算法的性能进行测试与分析。测试结果表明,该路由算法减少了无线传感器通信的能量消耗,延迟了传感器节点的死亡时间,改善了能量的有效性。     

无线传感器网络基于能量估计自适应算法SESP

无线传感器网络节点自身携带的能量有限,为了延长节点的使用寿命,在研究无线传感器网络节点能量消耗的基础上,提出一种基于同设备同参数能量估计的自适应算法SESP.SESP算法选择簇首时,不需发起通信以获知簇内其他节点的剩余能量,减少了簇内的通讯量,同时也简化了节点能量估计的计算复杂度,从而降低节点的能量,延长无线传感器网络的生命周期.     

基于中继节点机制的分簇数据融合算法

针对分簇的无线传感网中存在的簇首选择机制不合理以及在簇发送数据过程中因能耗不均衡而导致网络生命周期短的问题,提出基于中继节点机制的分簇数据融合算法.算法在不同分簇内根据数据信任值和能量信任值选择簇首,并在每个单独簇内选择一个中继节点,簇首收集簇成员的数据并融合,随之发送至中继节点;中继节点代替簇首与基站进行数据通信等工作,簇首在每轮的能量消耗会明显减少.对比传统的LEACH算法进行仿真实验,结果表明:采用此算法的无线传感器网络的生命周期有效延长了16%,并在一定程序上均衡了能耗.     

分布式能量高效的WSN非均匀分簇路由多跳算法

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%.     

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NS3的LEACH协议仿真与改进

LEACH协议是无线传感器网络中经典的分簇算法,但LEACH协议中簇首是随机产生的,存在簇首分布不均、网络拓扑和能量消耗不均衡的问题.基于此提出的LEACH-ER算法采用动态的簇首选举机制,将代表簇首间地理位置的RSSI信息和节点剩余能量引入选举权值,以均衡能量消耗和优化簇首分布.仿真结果表明,与LEACH算法相比,LEACH-ER算法有效地均衡了节点能耗,提高了能量利用率,从而大大地延长了网络寿命.     

无线传感器网络LEACH协议生命周期的改进

无线传感器网络跨层协议中,LEACH协议不考虑节点参数情况,采用随机概率方法选择簇首,不能保证能量较大的节点被选为簇首(CH),进而会降低网络寿命.为了有效选择簇首,提出改进的I-LEACH协议,将节点的剩余能量及节点与基站(BS)的距离作为优选条件,通过将网络划分为四个象限加以实现.实验仿真结果表明,在网络寿命、传输到基站的数据量、所用时间和能耗等性能方面,I-LEACH协议优于LEACH协议,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.     

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.     

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.     

A computer generator for randomly layered structures

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

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.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

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。     

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.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

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