最优预约信息包树形分解协议的研究

研究一点多址通信网络系统中信息包随机访问信道的树形冲突分解协议．对树形计算法做了推广，提出采用３个预约时隙和采用２个或３个动态预约时隙相结合信息包冲突分解方案；并用随机过程的分析方法对其进行了分析，得到了预约信道吞吐量和信道延迟特性．与双预约时隙比较，后两种方案延迟和系统稳定性得到明显改善．在对协议进行分析的基础上，进行了计算机模拟，证明了理论分析的正确性．     

多预约信息转发的协作信道预约多址接入协议

针对Ad Hoc网络中实时业务在背景业务繁重时信道接入效率低的问题,提出一种邻节点协作转发信道预约信息(CRI)的多址接入协议(M-CCRM).节点在发送数据分组前,选取多条CRI作为其数据开销,在控制该开销不超过预先设定门限的基础上,将这些CRI随分组一起发送;收到数据分组的邻节点提取其携带的CRI,记录下那些自己位于其预约范围内的CRI,避免在这些CRI的预约时段内接入信道.M-CCRM协议扩大了CRI的覆盖范围,解决了由于信道衰落和(或)分组冲突导致的CRI丢失问题,提高了实时业务的信道接入效率.仿真结果表明,当开销门限为0.02时,M-CCRM协议的实时业务发送失败概率比基本信道预约协议和基本协作预约协议分别降低了31％和20％.     

蜂群自组网双信道频率分集多址接入协议

提出了一种适于大规模蜂群自组网的双信道频率分集媒质接入控制(DCFD-MAC)协议。信道预约与数据分组传输分别在控制信道(CCH)与业务信道(DCH)进行,避免信道预约与数据传输碰撞,提高信道接入效率。同时,在信道预约过程中完成频道占用信息交互,网络节点自适应选择数据传输频道,实现数据频率分集并发传输,解决了网络隐藏终端与暴露终端问题,提升网络性能。最后,对该协议性能进行了仿真。仿真结果表明,该协议与传统MAC协议相比多址性能明显改善。     

无线局域网中多信道预约冲突避免接入协议研究

 为无线局域网提出了一种多通道预约冲突避免的随机多址接入协议,该协议综合了预约类协议和多通道的思想.采用平均周期分析方法对该系统进行分析,得到系统的信息分组发送成功的平均长度公式,分析了系统的吞吐量.分析表明,在使用任意确定数目的信道,在总带宽相同的情况下新协议表现出比单通道CS-MA协议更好的性能.     

短波地空IP网络中一种带预约的令牌协议

合适的信道接入技术是提升网络性能的关键.根据短波地空IP网络通信覆盖范围广、难同步、空中节点信息可能丢失的特点,设计出该网络一种新型的带预约短波令牌协议(HFTP-R),给出了区分空中节点优先级数据和常规级数据的预约算法,并利用OPNET软件进行了网络建模和不同参数配置下的仿真.仿真结果表明,该协议能提供较高的预约成功率和较好的实时性,且优先级预约比常规级预约更快接入信道,克服了短波令牌协议(HFTP)直接应用于短波地空IP网络时可能出现的通信中断,可满足网络需求.     

一种中小型无线自组网信道接入协议设计

阐述了目前主流的无线自组网信道接入协议,并针对目前工程应用环境提出了一种改进的无线自组网信道接入协议——信道预约多址接入(CAMA)协议。CAMA协议基于IEEE802.11DCF协议思想,通过对物理信道的动态划分,将控制信道与业务信道相分离,实现了业务数据在业务信道的无冲突发送,改善了网络的信道利用率和传输的可靠性。     

一种改进型低轨卫星多址接入协议研究

为了克服经典PRMA-HS协议中的双稳态问题和分组发送允许概率的静态性缺点,提出了一种基于状态响应的改进型分组预约多址接入协议。通过接收卫星基站的状态反馈信息,根据系统状态实时调整分组发送允许概率,使系统始终处在最佳状态。利用计算机对理想信道和随机误差信道条件下的协议性能进行了仿真,结果表明,采用状态响应机制能够克服经典PRMA-HS协议的双稳态问题,提高了协议的稳定性,增加了系统容量,降低了分组丢弃率。     

一种基于可靠预约ALOHA的智能车多车协作通信协议

针对典型交通场景下智能车多车协作的实时性、可靠性及分布式协作的要求,提出了基于可靠预约ALOHA的介质访问层信道接入协议,通过使用动态时分复用信道而提高车间通信的实时性,用预约时隙和广播机制而提高通信的可靠性与分布式特性,并设计了针对车队和超车的多车协作算法.同时,通过实验验证了通信协议及系统的可行性与可靠性.     

一种无线传感器网络低延时信道接入协议

针对无线传感器网络S-MAC协议中的延时问题,提出并设计了一种新型的MAC协议——LD-MAC协议。该协议采用提前预约多跳传输节点的方法,实现数据分组的快速转发,减少数据分组在网络中的延时,在一定程度上解决了节点早睡的发生。同时由于数据分组的快速转发,减少了节点的能耗。仿真实验表明:LD-MAC协议能够较好地降低能量消耗和数据传输延时。     

随机预约一点多址通信系统树形协议算法研究

本文对一点多址通信系统中的随机预约按需分配原则作了介绍，并用随过程的分析方法对树形冲突分解协议中有碰撞隔离和无碰撞隔离的算法进行了比较分析，同时还对协议进行计算机模拟，得到了信道平均吞吐率。     

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.     

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     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with