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1.
分析了并行序列自身特色,提出了一种并行序列的挖掘算法PSMA,PSMA在hash树的基础上对并行序列事件反复挖掘,产生频繁有效序列模式,它是对传统序列模式挖掘算法的改进.PSMA算法针对并行序列,能更有效地发现所有频繁并行序列模式.  相似文献   

2.
卢海涛 《科技资讯》2014,12(17):204-204
论文阐述了基于时间序列的模式挖掘的基本概念,对基于时间序列的模式挖掘经典算法和增量挖掘、时间序列分段线性表示及相似性算法进行了相对全面的介绍,对算法的特征做了详细的论述。  相似文献   

3.
基于数据挖掘的金融时序频繁模式的快速发现   总被引:2,自引:0,他引:2  
针对金融时间序列分析中注重快速作出趋势判断的特点,利用数据挖掘的思想和工具,提出一种金融时间序列模式快速发现算法.与传统的预测算法相比较,该算法对数据的分布和平稳性等方面的要求不高,不基于任何假设,能够非常快速地发现时间序列中的频繁模式,经过模式匹配后,可以用于金融时间序列的分析与预测.以实际汇率数据为例,证明了该算法的有效性.  相似文献   

4.
为了实现对数据流的序列模式挖掘,提出了基于数据流的序列模式挖掘算法MFSDS-1和MFSDS-2,它们均通过调整入选度的大小来调整保存信息的粒度.算法MFSDS-2利用分层存储结构,不仅能更好地保存序列信息,而且可以通过与全局序列模式的对比得到当前活动的一些异常序列模式.实验结果表明,基于分层存储的算法MFSDS-2的效率比算法MSFDS-1高.  相似文献   

5.
全排列问题的递归算法结构清晰,可读性强.为了提高排列的效率,给出了全排列递归算法在MIMP-CREW模型和单指令多数据流的EREW模型上的并行化算法及实例分析.给出的算法成本是最低的.  相似文献   

6.
序列模式挖掘是在多个有序事件序列中查找出现频率大于某个阈值的序列模式的数据挖掘方法,自从1995年序列模式挖掘的概念被提出以来,人们不断地对序列模式挖掘算法进行研究和改进,本文介绍了一种新的序列模式挖掘方法-CSE算法及其具体实现方法,并对该算法性能做了初步的评价。  相似文献   

7.
一种序列模式的概念及挖掘算法   总被引:1,自引:1,他引:0  
介绍了一种时间序列模式的形式和概念,讨论了其相关的挖掘算法.将时间序列模式既用于具有时间关系的购买行为的分析,以揭示购买行为后面一种序列关系信息,又用于其他有时间关联的事件分析.挖掘算法由以下几部分构成建立频繁物品集,进行数据处理和转换,并生成候选子序列,通过验证后,得到长度为2,3,…的序列集合,从中选出独立最大序列即为所求.通过实例指出了该算法和传统的Aprioriall算法的不同之处.结果表明,这种序列模式在网络通信、气象分析等领域具有广阔的应用前景.  相似文献   

8.
SAX是一种典型的符号化特征表示方法.该方法在时间序列特征表示中不仅可以有效地降维、降噪,而且具有简单、直观等特点.时间序列长度不一、特征表示过程中信息损失等问题的存在,使得常规的分类算法难以很好地完成分类任务.在对时间序列数据进行基于SAX符号化的BOP表示方法的基础上,提出了结合集成学习中AdaBoost算法进行分类的新方法,实验结果表明,该方法不仅能很好地处理SAX符号化表示中的信息损失问题,而且与已有方法相比,在分类准确度方面也有了显著的提高.  相似文献   

9.
序列模式挖掘是数据挖掘中最重要的研究课题之一。基于记录频繁集各元素的Ctid表的基础上,有研究者提出一种渐进式序列模式挖掘算法IMSP,目的是支持度保持不变,而数据库变化不大时,如何利用前次的结果和中间结果,以加速本次挖掘过程。笔者深入分析了算法IMSP结构,指出该算法在时间复杂度,挖掘规则的完备性上的不足,同时也指出利用该算法所可能得到的错误结果。  相似文献   

10.
从事务数据、时间序列数据等数据库中挖掘频繁模式已在数据挖掘领域中得到了广泛地研究.针对目前已有的Apriori算法和频繁模式增长算法在时间和空间等方面的复杂性和低效性,提出了一种新的数据结构——事务模式树,用来存放待挖掘的事务信息,同时给出一种基于该数据结构的挖掘算法——事务模式树分层挖掘算法.最后,把该算法应用于保险业务.结果表明,该算法简单高效,值得推广.  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
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。  相似文献   

15.
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  相似文献   

16.
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  相似文献   

17.
18.
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.  相似文献   

19.
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).  相似文献   

20.
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.  相似文献   

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