基于核的模糊c均值聚类算法的收敛性定理

利用Zangwill收敛性定理, 证明了基于核的模糊c均值聚类算法(KFCM)的收敛性. 结果表明, 当核函数在给定数据集上诱导的距离矩阵满足一定条件时, KFCM算法产生的迭代序列收敛或至少存在一个子序列收敛于KFCM聚类模型目标函数的局部极小值点或鞍点.     

多视角核K-means聚类算法的收敛性证明

用Zangwill收敛性定理对多视角核K-means(MVKKM)的收敛性进行了分析.结果表明,当满足一定的条件时,MVKKM生成的迭代序列收敛或至少存在一个子序列收敛于算法目标函数的局部极小值或鞍点,并在Matlab环境下,通过实验验证了算法在不同视角和不同的权重指数下的收敛性.     

基于免疫粒子群的K均值聚类算法

粒子群算法是一类高效求解连续函数优化的随机搜索算法,在K均值聚类算法中得到广泛应用,但是在群体进化后期容易陷入局部极值,针对算法缺点,提出了一个新的聚类算法--基于免疫过程的粒子群K均值聚类算法,并将此算法与K均值聚类算法和粒子群K均值聚类算法进行比较.理论分析和数据实验证明,该算法有较好的全局收敛性,不仅能有效的克服传统的K均值聚类陷入局部极小值的缺点,而且全局收敛能力优于基于粒子群的K均值聚类算法.     

基于粒子群优化聚类算法的点模型简化

为了有效地简化稠密采样点模型,提出了一种基于粒子群优化聚类算法的点模型简化方法.引入了具有强大全局寻优能力的粒子群优化算法,对传统的k-均值聚类算法进行改进,基于改进的聚类算法对点模型进行简化,选取具有最优个体适应度函数的粒子作为原始采样点集的最终简化模型.算法聚类依据采样点的空间位置、法向和曲率的邻近性,实现了点模型表面区域几何特征保持的简化.同时在聚类区域的划分中考虑了曲率阈值和区域半径,使得算法在有效地保持特征边界和曲面细节的同时,能够生成高质量的简化曲面.实验结果表明,粒子群优化的k-均值聚类算法克服了传统聚类算法容易陷入局部极小的缺点,具有更好的全局收敛性和较快的收敛速度.该简化方法在有效简化点模型的同时,很好地保持了原始模型的几何形状,且在相同简化效率下能够生成更高质量的简化曲面.     

基于泛函序列的模糊C均值算法

在模糊C均值算法的基础上,通过对原有算法进行改进,以达到加快聚类速度的目的。提出了一种使用最速下降法来优化模糊C均值算法的方法。从传统的模糊C均值算法中推导出关于聚类中心的泛函迭代序列,并证明了该序列的收敛性,以及该序列收敛到的不动点是目标函数达到的极值点。而后,使用最速下降法加快该序列收敛速度。最终通过实验结果来验证了理论的可行性。在其迭代过程中,对于越偏离理论聚类中心的点,下降趋势比传统模糊C聚类算法就越明显。     

一种新的混合蚁群聚类算法

针对蚁群聚类算法存在收敛速度慢、易陷入局部最优等缺陷,通过在蚁群聚类算法的每次迭代过程中引入遗传算法,提出一种混合蚁群聚类算法.它利用遗传算法全局快速收敛的特性,提升了蚁群聚类算法的收敛速度,同时,遗传算法中的交叉、变异操作扩大了解空间的搜索,帮助蚁群算法跳出局部最优.仿真试验验证了算法的性能.     

基于二阶段微粒群优化模糊C-均值算法的模糊聚类分析研究

针对常规动态聚类方法对初始聚类中心的敏感性和容易陷入局部最优的缺点等问题,提出了基于二阶段微粒群优化模糊C-均值算法(TPSOFCM),并将此算法与现有的模糊C-均值聚类算法和基于多阶段的模糊C-均值算法进行比较。该算法对Iris数据进行聚类,计算结果表明:该算法有较好的全局收敛性,不仅能有效地克服传统的模糊C-均值算法易陷入局部最优解的缺点,而且全局收敛能力优于模糊C-均值聚类算法和基于多阶段的模糊C-均值算法。     

基于K中心点的文档聚类算法

K中心点算法是一个常用的聚类算法,它的主要缺陷是容易陷入局部极值,计算代价太高.本文先构造一个运用余弦相似度的K中心点文档聚类算法,然后提出一个改进算法,该算法不增加计算的复杂性,显著改进文档的聚类结果.最后,将该改进算法作为局部搜索过程嵌入到迭代局部搜索结构中,构造一个基于K中心点的迭代局部搜索文档聚类算法,进一步改进了文档聚类结果.试验结果表明该算法显著改进了文档聚类结果.     

可能性熵聚类

研究了基于可能性熵理论的聚类问题．首先定义并讨论了可能性熵,继而将可能性熵引入聚类分析,提出了可能性熵聚类算法．它考虑到熵聚类的全局和局部效应,具有清晰的物理意义和数学特征．该算法还能在聚类过程中自动地确定分辨率参数,克服了对于噪声和外围点的敏感性．仿真实验证明,即使各类大小不一,数据集被强噪声所污染时,该算法仍能有效地估计各类中心．     

一种改进的K均值算法

K均值算法是以随机的方式选择初始聚类中心,这使得K均值算法容易陷入局部最优,收敛性能不稳定。针对这一缺陷,该文对K均值算法进行改进,提出一种逐步选择距离差异极大的个体作为初始聚类中心的算法。实验结果表明,改进后的算法收敛性能确实比K均值算法优越。     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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