一种容延迟移动传感器网络节能MAC协议

针对容延迟移动传感器网络(DTMSN)中传感器节点高能耗、高动态等特点,提出了PC-MAC协议.在IEEE 802.11MAC协议的基础上,结合现有MAC协议的特点,将改进后的数据传输机制和传输功率控制技术引入到DTMSN的MAC协议设计中.最后,通过仿真实验证明,PC-MAC协议在容延迟移动传感器网络环境中,在不同的节点数量时,其节点的平均能耗、数据包投递率及网络吞吐量均有良好的表现.     

基于距离门限的水声网络自适应路由协议

针对水声传感器网络长时延和高能耗的问题,提出了基于距离门限的自适应路由协议ARBDT (Adaptive Routing Protocol Based on Distance Threshold)。该协议采用单路径逐跳信息传输方式,节省了路由开销;同时根据网络密集程度自适应地调整距离门限,抑制了冗余节点的回应,降低了控制包冲突的概率,使发送节点能快速获取转发节点。仿真结果表明,与SBR（Sector Based Routing）协议相比,ARBDT协议能缩短时延,降低网络能耗,从而获得更好的性能。     

基于位置预测的OLSR协议研究

针对空战环境的复杂性和无人机网络中节点的高动态运动引起网络拓扑变化快的特点,提出了一种自适应基于位置预测的优化链路状态路由(ALOLSR)协议,当GPS信息可用时,该协议将OLSR协议中的拓扑控制信息代替为本节点的位置和速度信息,通过MPR泛洪使网络中每个节点获知其他节点位置和速度,在路由选择上充分利用节点定位信息选择稳定的链路。利用NS3仿真无人机组网,结果表明,ALOLSR协议提高了网络分组交付率,降低了数据传输时延。     

一种自适应占空比的无线传感器网络MAC协议

本文提出了一种自适应占空比的无线传感器网络MAC协议(AD-MAC),它可以使节点根据网络流量负载的变化自适应地调整自己的占空比.仿真结果表明,AD-MAC协议能够有效地提高网络的生命周期,降低节点的能量消耗.     

移动Ad Hoc网络中提高路由稳定性的动态备份多径路由

为了解决移动Ad Hoc网络中备份路径过期问题,提出了一种新的动态备份多径路由(DBR)协议.该协议采用洪泛方式建立主路径,使主路径为源节点和目的节点间跳数最小的路径,并利用周期性发送的HELLO包为主路径上的链路按需构建局部备份路径.DBR协议有效地利用周期性发送的HELLO包,降低了备份路径建立过程中的控制负载.利用HELLO包所交互的当前邻居节点信息构建生存时间尽可能长的备份路径,解决了备份路径的过期问题.理论分析表明,该协议适用于节点密度较大的移动环境.仿真实验表明,该协议在移动性强的环境下具有较好的性能.     

一种带移动预测的Ad-Hoc网络路由协议

对无线Ad Hoc网络(MANET)路由协议作了简要介绍和比较·基于按需式距离矢量路由协议(AODV),提出了一种在路由发现和路由维护两个阶段都带移动预测的路由协议PAODV·该协议通过GPS系统获知移动节点的位置、速度、移动方向等信息,以链路中相邻节点在最大有效距离范围内的运动预测时间为判断指标,一方面在路由发现阶段建立相对稳定的路由,另一方面在路由维护阶段对链路断开提前进行预测,以降低包的丢失率和重新路由时间开销·仿真结果说明,PAODV比AODV有较低的控制包开销和较高的包投递率·     

移动预测的无人机自组网路由协议

在无人机自组网中,针对贪婪地理路由协议采用周期性信标交换导致邻居表不能准确反映邻居节点位置的问题,提出了一种基于移动预测和链路保持时间的路由协议MP-GPSR。该协议综合考虑节点的移动位置和链路保持时间来选择下一跳,减缓了节点高速移动带来的不利影响,同时使用两跳邻居节点的位置选择下一跳来避绕路由空洞,降低了传统边界转发的路径冗余。仿真结果表明:该协议不但提高了数据分组交付率,而且降低了平均端到端时延和控制开销。     

一种带移动预测的Ad-Hoc网络路由协议

对无线Ad—Hoc网络(MANET)路由协议作了简要介绍和比较．基于按需式距离矢量路由协议(AODV)，提出了一种在路由发现和路由维护两个阶段都带移动预测的路由协议PAODV．该协议通过GPS系统获知移动节点的位置、速度、移动方向等信息，以链路中相邻节点在最大有效距离范围内的运动预测时间为判断指标，一方面在路由发现阶段建立相对稳定的路由，另一方面在路由维护阶段对链路断开提前进行预测，以降低包的丢失率和重新路由时间开销．仿真结果说明，PAODV比AODV有较低的控制包开销和较高的包投递率．     

移动自适应的无线传感器网络MAC协议研究进展

包含运动节点的无线传感网应用得到了越来越多的关注.节点的运动对于无线传感器网络MAC（Medium Access Control）协议设计提出了很多挑战.文中研究当前节点运动处理的方法.首先介绍了节点运动的特征及其对于网络的影响.其次,指出了移动自适应的无线传感器网络MAC协议的发展脉络,对于典型协议进行比较,并指出各自的优缺点.最后,展望了这类协议的发展趋势和方向.     

一种面向移动物联网环境的动态路由新协议

针对车辆自组织网络(VANET)等移动物联网中网络拓扑变化频繁问题,我们提出了一种面向移动物联网环境的动态路由新协议.该协议将连通概率作为重要参数,其计算方法依据参数节点和它的最近节点的间距,间距的分布按照指数分布;协议中采用了贪婪机会转发(GOF)策略,GOF策略在包的递交率和平均跳数等方面有效提高了车辆网等移动物联网目标的性能.一系列的测试表明,与传统的路由协议相比,我们设计的协议在递交率、平均跳数以及端到端的延时等方面均表现出很好的效果.     

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)

正~~     

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