基于关联规则的中文文本分类算法的改进

随着中文电子刊物和Web文档数量的飞速增加,中文文本自动分类工作变得日益重要.将文档视为事务,将关键词视为项,文本预处理时提出特征权重阈值,用构造的分类器对未知文档分类时,采用了CDD(Class Differen-tiate Degree)改进算法,对基于关联规则挖掘的中文文本自动分类方法进行了改进.实验结果表明,该算法能较快地获得可理解的规则并且具有较好的宏平均和微平均值.     

基于位置的特征项权重算法

Web文本分类是Web文本挖掘的主要内容,而特征项权重的计算是web文本分类中一个非常重要的步骤。Web文本一般由标题、描述和正文三部分组成。根据Web文本的这一特点,本文提出了一种基于位置的特征项权重算法,并使用此算法对Web文本进行了分类实验。实验结果表明该算法有效提高了Web文本分类系统的分类性能。     

一种基于VSM文本分类系统的设计与实现

阐述了一个基于改进向量空间模型的中文文本分类系统的设计与实现 ,包括对该系统的结构、预处理、特征提取、训练算法 ,分类算法等关键技术的介绍 .通过引入结构层次权重系数来改进文本特征项权重 ,同时提出一种新的训练算法和文本相似度域值计算方法 .实验结果证明 :该分类系统能有效地提高文本分类效果 ,开放性测试的平均准确率在 80 %以上 ,且平均查全率达到了 86 % .     

基于语义理解的Bayesian-Boosting情感分类

提出将语义理解与统计学方法相结合的机器学习算法来进行文本情感分类。首先提取文本中的情感词汇作为特征,利用统计学方法得到特征的初始权重,然后通过分析文本语义结构修改特征权重,最后利用Bayesian算法和以Bayesian作为基本分类算法的Boosting算法进行分类。实验表明,基于语义理解的Bayesian分类算法的分类准确率高于仅基于统计学的Bayesian分类算法,基于语义理解的Bayesian-Boosting算法的分类准确率最高,达到了90%。     

iRIPPER——一种改进的基于规则学习的文本分类算法

基于规则学习的文本分类算法RIPPER具有易理解、易优化、高效率等特点，但是当规则所涉及的特征项很多的时候，上述优点不复存在。基于层次的规则学习算法hRIPPER采用了层次架构对RIPPER进行了改进，但其对特征项的过滤仍然有限。针对RIPPER,hRIPPER在规则学习过程中出现的问题，对规则学习的分类算法进行改进，提出了一种改进的基于规则学习的文本分类算法iRIPPER，在规则学习的同时进一步过滤噪音特征项。实验证明，该方法不但有效地提取了特征项，生成较少的规则，提高了算法的准确率和召回率，而且缩短了生成规则的时间，从而改进了规则学习分类算法的性能。     

一种基于粗糙集的文本分类规则抽取方法

随着文本数据库的日益增大，寻找新的文本数据处理方法变得十分紧迫。本文将粗糙集理论应用于文本自动分类的规则提取，提出了基于粗糙集理论的文本分类方法。把文本特征项的权值进行离散化处理后，作为规则的条件属性，文本所属的类别用作决策属性，构造决策表，然后通过决策表的知识约简算法提取出文本的分类规则。实验结果表明，该方法提取规则的分类正确率较高，分类速度较快。     

基于VSM的中文文本分类系统的设计与实现

文本分类是指在给定分类体系下,根据文本的内容自动确定文本类别的过程。该文阐述了一个基于向量空间模型的中文文本分类系统的设计和实现。对文本分类系统的系统结构、预处理、特征提取、训练算法、分类算法等进行了详细介绍。引入标题权重系数改进词语权重,并提出了一种新的分类算法。实验测试结果表明查全率和准确率均达到90%左右,而且标题权重的引入和新分类算法的实施有效地改善了分类性能。     

大数据环境下朴素贝叶斯分类算法的改进与实现

朴素贝叶斯分类算法是一种简单并且高效的分类算法,但条件独立性假设在现实中很难满足,导致其性能有所下降.为了解决该问题,本文在关联规则和置信度的基础上对该分类算法进行了改进.通过挖掘出来的关联规则和该规则的置信度,对不同的属性赋予不同的权重,同时实现了该分类算法的MapReduce化,从而在保持简单性的基础上有效地提高了朴素贝叶斯分类算法的分类性能.动车组运维实验表明:该算法提高了分类的准确率和效率.     

中文文本分类技术比较研究

文本分类中特征选择、权重计算及分类算法三个阶段中都存在一些经典方法,在实际的中文文本分类任务中,如何从各阶段不同方法的组合中找到一个好的组合成为值得研究的问题。比较研究中文文本分类中各阶段经典方法的不同组合对分类效果的影响结果表明:采用CHI特征选择方法、TFIDF权重计算方法及SVM分类方法的组合为最佳组合。     

基于关联的自适应分类规则挖掘方法

讨论了对分类规则的挖掘采用基于关联的分类方法.关联分类规则挖掘方法主要包括两大处理步骤:第一步利用分类关联规则挖掘算法挖掘出有关的分类关联规则;第二步就是基于所挖掘出的分类关联规则构造一个分类器.详细介绍了该方法的实现算法和部分数据结构.     

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…     

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.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.