Initializing K-means Batch Clustering: A Critical Evaluation of Several Techniques

K-means clustering is arguably the most popular technique for partitioning data. Unfortunately, K-means suffers from the well-known problem of locally optimal solutions. Furthermore, the final partition is dependent upon the initial configuration, making the choice of starting partitions all the more important. This paper evaluates 12 procedures proposed in the literature and provides recommendations for best practices.     

基于STR模型的CPI波动与货币供应量关系的实证分析

针对居民消费价格指数(CPI)的波动与货币供应量之间的关系,若用线性回归来研究,将会忽略这样两个问题:1)此函数关系是否一成不变;2)它们之间的影响是否存在对称性。本文以非线性STR模型技术来分析两者之间的非线性、非对称关系。研究发现,以logistic函数作为过渡函数的STR模型能很好地描述CPI波动与货币供应量的非线性动态关系。模型表明,在1993年1月到2010年12月期间,中国CPI波动与货币供应之间存在明显的非对称性,具有很强的非线性特征,两者之间存在机制转换动态特征。紧缩的货币政策机制下,CPI波动加剧;从宽的货币政策机制下,CPI波动主要由市场经济自我调控。
     

A fast pseudorandom number generator with BLAKE hash function

This paper presents a fast pseudorandom generation algorithm, which is based on the BLAKE hash function and can pass the random test of the NIST (National Institute of Standards and Technology) Statistical Test Suite. Through theoretical analysis and experimental imitation, our new algorithm is proven to be more secure and efficient than G-SHA1. Simultaneously, we introduce and discuss the BLAKE in detail. Its security shows that can be utilized to generate pseudorandom bit sequences, which the experimental results show the BLAKE hash function has excellent pseudorandomness. Therefore, we believe the BLAKE is one of the most potential candidate algorithms of SHA-3 program.     

NECESSARY AND SUFFICIENT CONDITION FOR GLOBAL CONTROLLABILITY OF A CLASS OF AFFINE NONLINEAR SYSTEMS

In this paper, we investigate the global controllability of a class of n-dimensional affine nonlinear systems with n- 1 controls and constant control matrix. A necessary and sufficient condition for its global controllability has been obtained by using the methods recently developed. Furthermore, we generalize the above result to a class of affine nonlinear systems with a block-triangular-like structure. Finally, we will give three examples to show the applications of our results.     

2,6-二羟基对苯二甲酸的合成及表征

以3,5-二羟基苯甲酸为原料,在常压、二氧化碳条件下,以Kolbe-Schmitt反应机理进行羧化制备2,6-二羟基对苯二甲酸,通过高效液相色谱、红外和核磁对产物结构和纯度进行了表征,发现产物结构正确,且纯度可达99.62%.实验结果表明,该工艺路线可行,产物纯度高,是一个简单可行的好方法.     

关于De Morgan代数的不动核

研究了Ｄｅ Ｍｏｒｇａｎ代数中的不动核的性质，特征，并且给出了Ｄｅ Ｍｏｒｇａｎ代数含有不动核的充分必要条件，同时又对不动核的个数问题做了进一步的讨论，得到了一些结果。     

On functional decomposition of multivariate polynomials with differentiation and homogenization

This paper gives a theoretical analysis for the algorithms to compute functional decomposition for multivariate polynomials based on differentiation and homogenization which were proposed by Ye,Dai,and Lam(1999) and were developed by Faugere,Perret(2006,2008,2009).The authors show that a degree proper functional decomposition for a set of randomly decomposable quartic homogenous polynomials can be computed using the algorithm with high probability.This solves a conjecture proposed by Ye,Dai,and Lam(1999).The authors also propose a conjecture which asserts that the decomposition for a set of polynomials can be computed from that of its homogenization and show that the conjecture is valid with high probability for quartic polynomials.Finally,the authors prove that the right decomposition factors for a set of polynomials can be computed from its right decomposition factor space.     

河池市土地资源可持续利用的初步探讨

该文在实地调查和广泛收集资料的基础上，分析了广西河池市土地利用现状特点和土地资源潜力，提出了实现土地资源可持续利用的对策。     

普朗克黑体谱要求钟速同步的传递性等价于第零定律

弯曲时空中的平衡热辐射，表现出用坐标量表示的普克黑体谱。以此为基础，论述了钟速同步的传递性等价于热平衡的传递性。第零定律保证全时空可以定义统一的钟速。     

MULTIPLE CRITERIA DECISION MAKING： DISCORDANT PREFERENCES AND PROBLEM DESCRIPTION

There are many practical decision problems where decision makers＇ preferences may be inconsistent and contradictory. In this paper, new methods for ordering and classifying multi-attribute objects by discordant collective preferences are suggested. These methods are based on the theory of multiset metric spaces. The proposed techniques are applied to ranking companies and a competitive selection of projects, which are estimated by several experts upon multiple qualitative criteria.