Deep Web数据源的发现和分类

为了最大限度地获取Deep Web数据源信息,并对获取到的数据源信息进行分类,方便后续的数据源集成工作以及用户的检索使用,提出了一种基于数据库的实时的Deep Web数据源搜索框架,该模型在本地服务器上设计安装"数据源发现应用程序"模块,通过各搜索网站下载安装的"客户端数据源应用程序"模块实现数据信息的对接和实时传送.为了保证检索效率,利用知网结合同义词词林对各大被检索网站进行分类.     

基于频繁结构的Deep Web 查询接口集成

随着网络规模的日益扩大,海量的信息被"深藏"于各类在线数据库中,用户只能通过查询接口才能获取其中的数据,这部分内容称之为Deep Web;因此对同一领域的Deep Web数据进行集成是非常必要的。查询接口的集成是其中一个非常关键的子问题。查询接口的集成分为模式匹配和模式集成两个步骤;重点研究集成查询接口中属性布局的确定。Deep Web中查询接口数量巨大,以及动态性与异构性的特点给该问题带来了巨大的挑战。将查询接口的结构建模成一棵树,然后通过挖掘频繁的模式子树来构建集成的查询接口树,使其最大化地满足属性间的结构约束和顺序约束。该算法具有较低的时间复杂度,并具有很好的扩展性,对八个领域的查询接口进行集成的实验结果证明了算法的有效性。     

Deep Web数据源聚类分类算法研究

在Internet技术飞速发展的今天,人们对依靠Web引擎搜索可用信息的实效性、快捷性的研究在不断的深入。然而许多Web信息已经被各种各样可搜索的在线数据库所深化,并被隐藏在Web查询接口下面。传统的搜索引擎由于技术原因不能索引这些信息——Deep Web信息。由于Deep Web数据的异构性和动态性,有效地把这些信息加以利用是一件具有挑战性的工作。因此,本文分别提出了基于Deep Web查询接口的Deep Web数据源聚类和分类算法,为Deep Web信息检索方法的研究提供了一定的理论依据。     

Deep Web站点分类研究进展

如何高效、准确地组织和检索Deep Web蕴含的高质量信息已经成为未来Web挖掘和数据库领域面临的一项崭新课题和挑战,而Deep Web分类则是Deep Web信息检索的基础.该论文综合论述了Deep Web信息集成的研究概况,重点分析了结构化Deep Web分类的主要方法和存在的主要问题,并且讨论了解决这些问题的可能方法;最后对未来工作进行展望.     

基于领域本体的Deep Web内容获取技术研究

为了用户方便快速地使用Deep Web中的信息,对在线数据库中的内容进行获取是一种行之有效的方法.本文设计了一种基于领域本体的Deep Web数据库内容获取技术,利用训练数据库训练构建领域本体,通过领域本体中的有效查询项获得查询关键字集,对数据库内容进行查询,最终获得Deep Web内容.通过实验证明,该方法能育效地获...     

Deep Web技术在科学数据共享平台中的应用

Deep Web中蕴含了海量的可供访问的信息,并且还在迅速地增长。随着互联网应用的发展,网上的在线数据库大量涌现,Deep Web数据集成成为当前信息领域的一个研究热点。为了方便用户查询数据,对Deep Web技术的应用进行了研究,提出了Deep Web技术在科学数据共享平台中的架构,并阐述了具体的实现。     

旅游目的地营销系统(DMS)中异构数据集成中间件的设计

分析了旅游目的地营销系统(DMS)的数据库现状,探讨了其数据库资源的特点和旅游者、旅游企业对数据集成的需求.通过对不同数据集成方案的比较分析,采用基于Web Ser-vice异构数据集成中间件技术,设计了DMS的异构数据集成中间件,分析该中间件的设计思路与实现流程.阐述了中间件配置管理、查询构造、查询分解、查询执行和重组等模块的设计.该异构数据集成策略,可以使DMS系统数据库与旅游企业自身数据库连接,以实现旅游信息资源的共享.     

基于启发式规则的Deep Web接口发现

为了有效地利用Deep Web资源,Deep Web数据集成成为当前研究的热点之一.能否高效地发现Deep Web站点是Deep Web数据集成的基础和关键.在此,提出了一种Deep Web接口发现方法,包括基于领域知识来确定合适的查询提交词和用启发式规则发现领域内Deep Web接口.实验结果表明,该方法达到了较高的准确率和召回率,具有良好的可行性和实用性.     

Deep Web数据集成系统中的查询效率优化

Deep Web能够提供大量高质量的信息,为了有效地利用这些信息,建立Deep Web数据集成系统是重要手段。Deep Web数据集成系统的查询效率是其应用的关键。本文采用建立本地索引数据库的方式以提高查询效率,在此基础上提出了其相应的更新策略,并给出了算法分析。     

异构信息源集成技术

异构信息源集成技术提供统一接口,使各种基于因特网的应用能迅速、准确地提取所需信息,为用户屏蔽各种信息源的异构性.这种异构信息源的集成技术从传统的结构化的异构数据库扩大到半结构化的大量Web页面信息及无结构的信息.对集成技术的方法,如数据模型、Web信息、描述语言XML、主流软件开发技术及信息智能搜索、查询重写、查询分析等进行了分析,给出了半结构化异构信息源集成的系统架构,并指出该项技术未来发展趋势.     

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.     

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.     

A computer generator for randomly layered structures

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

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。     

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     

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     

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

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.