一种有效检索和更新移动对象的混合索引结构

由于无线通信技术持续不断的发展和基于定位服务的广泛应用,存储和处理移动对象数据变得尤为重要。提出了一种移动对象混合时空索引结构,即HTVKDB-tree,此索引结构在KDB-tree的基础上结合了直接存取移动对象位置的辅助索引结构。在结点中加入时间和速度参数,使其支持索引移动对象,并且索引结构能够支持未来的位置检索。此外,增加了一个指向中间结点访问表的主存结构以支持自底向上的更新算法以降低更新代价。     

基于改进R*树的移动GIS多尺度渐进传输与表示

针对传统单一尺度空间数据在低速无线网络环境中难以由移动GIS下载与表示的问题,在研究矢量数据多尺度表示与R*树空间索引的基础上,设计并实现了改进的多尺度R*树空间索引算法.该算法使得R*树中非叶子结点能够关联合适尺度的空间对象实体,保证海量的矢量数据在服务器端得到了有效的多尺度组织.在该算法的基础上,借助于移动GIS端所设计的缓冲式多尺度空间数据存储与管理,以及基于请求/应答模型的GML流式数据传输,设计并实现了面向移动GIS的矢量数据多尺度渐进传输模型,从而使得移动GIS能够以较高的效率下载和表示各种尺度的空间数据.通过真实的土地利用现状空间数据实验,验证了该方法在无线网络情况下能够有效地提高移动GIS的数据传输效率.     

基于固定网络的移动对象轨迹查询

在基于固定网络的移动对象轨迹查询方面.现有的索引模型只能管理移动对象当前和过去或将来轨迹的查询,它们都不能同时实现移动对象的现在,过去和将来轨迹查询.本文在IMORS的索引结构基础上进行改进并提出了一种新的索引结构.它能实现基于固定网络的移动对象的全时态索引.     

基于链表结构的频繁模式树构造

FP-Growth算法在关联规则挖掘中是最经典的算法,主要通过频繁模式树(FP树)避免生成候选频繁项目集.针对FP-Growth算法中耗费内存严重的问题,采用链表存储方式,给出了FP-Growth算法的实现方法,其中单个结点采用链表形式来产生,频繁模式树采用左孩子右兄弟的存储结构来组织.在此基础上利用索引表,实现了对频繁模式树中共同前缀结点的快速查找,提高了频繁模式树构造的效率,解决了FP树构造算法中数据存储的瓶颈问题.最后以天体光谱数据和城市土壤数据作为数据集分别对该算法进行测试,实验结果表明,该方法的构造效率要明显优于基于顺序结构的FP-Growth算法.     

面向移动对象范围的混合索引结构

许多时空应用(如火灾模拟等)需要高效地查询移动对象的变化范围,针对此需求提出了基于TPR-tree和GF索引方法的两种混合索引结构,以支持对移动对象当前和未来范围的预测时空查询.在代价模型分析的基础上,基于模拟数据集的实验结果表明,这种混合索引方法能够有效地支持对移动对象变化范围的预测查询.     

路网中基于RQOP树的移动对象索引技术研究

基于位置的信息服务需要高效的索引方法来管理移动对象.针对PMR QUAD树索引路网空间时不平衡、部分路段重复存储且索引结构可调整性差的问题,用RQOP树对路网空间按照路段的空间分布进行划分,使树的高度尽可能低,改进基于路网的动态组合索引结构.对照实验表明,基于RQOP树的索引结构提高了查询效率.     

一种增量倒排索引结构的设计与实现

针对主题爬行器获取网页更新速度快的特点, 提出一种用于网络搜索引擎的增量索引结构. 在建立倒排索引时, 每个词项的记录表以链接块的形式存放于倒排索引文件中, 每次新分配的块大小递增. 该索引结构解决了倒排索引连续存储所带来的难以更新问题. 实验结果表明, 与支持实时更新的传统链表式存储方式相比, 这种索引结构能提供更高效的检索, 采用以空间换时间的方法有效地提高了索引的更新效率.     

基于最小生成树的R~*-树结点分裂算法

针对R*-树应用到逆向工程领域时遇到的适用性差等问题,提出了一种新的R*-树结点分裂算法.该算法将R*-树索引结点表示为轴向包围盒,依据轴向包围盒外接球间的重叠度计算结点相似度,并将其作为权值构建结点无向连通图,用来求解结点无向连通图的最小生成树.沿最大权值边将最小生成树分裂为2棵子树,并基于结点外接球体积对R*-树结构进行优化,从而实现了R*-树结点分裂.实例表明,R*-树结点分裂算法可处理各种复杂数据的结点分裂问题,能够有效地提高R*-树的构建效率及空间数据的查询效率.     

几何对象统一表示的R~*-tree结点分裂算法

针对R*-tree应用到逆向工程领域时遇到的适用性差等问题,提出一种新的R*-tree点分裂算法.该算法将R*-tree索引结点表示为最小包围盒,依据最小包围盒外接球间的重叠度衡量结点间的相似值,结合k-means算法,随机提取两个结点作为初始分簇中心,依据结点间的相似值计算新的分簇中心并迭代分簇,直到分簇中心不再变化,实现R*-tree的结点分裂.实例表明,该算法可处理各种复杂几何对象的R*-tree结点分裂问题,并可优化R*-tree结构,显著提高结点的分裂效率.     

CF-HNLBI:一种新的闪存数据库B-树索引

提出了一种新的基于B-树的闪存数据库索引——CF-HNLBI索引.使用链表组织缓冲区中的更新信息,减少了缓冲区遍历时间,通过链表结构减少冗余信息,提高了缓冲区利用率.将缓冲区分为冷区和热区,并采用基于更新信息频度的替换算法,有效地减少了闪存写操作次数.实验结果表明,CF-HNLBI索引比其他已有索引具有更好的性能.     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

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.