改进的优势区分矩阵及其求核方法

研究了优势关系下不协调决策表的优势区分矩阵及其求核方法。用反例指出利用文献[6]中的优势区分矩阵来求核的方法是错误的,给出一个改进的优势区分矩阵的定义和求核方法,其空间和时间复杂度都优于现有的算法。     

基于优势区分矩阵的求核方法

在提出基于优势关系粗糙集方法下的类区分矩阵概念后,为解决不一致数据问题,新的优势区分矩阵定义及其求核方法被提出,但是该方法计算代价高。为了能够快速求出存在不一致数据的信息系统的核,该文给出改进的优势区分矩阵定义和求核算法,其空间和时间复杂度都优于现有的算法。实验证明,该算法适用于处理大数据集。     

对新简化差别矩阵的研究

通过反例证明当决策表含不一致对象时,无法通过简化差别矩阵得到正确的核和约简.产生该问题的原因在于简化差别矩阵和简化决策表对不一致对象的处理均存在欠缺.提出新简化差别矩阵(NSDM)定义,通过利用新简化决策表把一致对象和不一致对象分开存放的特点修正了这两处缺陷.NSDM能够处理含多种不一致对象的决策表,并且能够得到正确的核和约简.利用前人的基于差别矩阵的求核和求约简算法分别以NSDM和简化差别矩阵为基础求核和约简,然后再利用核和约简的定义求核和约简,通过比较证明以NSDM为基础得到的核和约简是正确的.这说明NSDM可以有效地处理不一致对象并且通过NSDM能够得到正确的核和约简.这个实验同时验证了原有的以差别矩阵为基础的求核和求约简的算法不加改动就可以在新差别矩阵上使用.     

广义约简、核与分辨矩阵

针对粗糙集理论中计算决策表核属性时出现的若干问题,讨论并分析了这些问题产生的原因.在此基础上,给出了不同目标下的广义约简定义,提出了必要区分关系和非必要区分关系等概念,由此给出了一般意义下的分辨矩阵定义.根据广义约简的定义,将已有的改进差别矩阵求核方法与早期Skowron等人提出的经典分辨矩阵求核方法作了对比,证明了两种方法完全相I司.     

基于粗糙集和信息熵的属性约简算法

粗糙集具有很强的定性分析能力，通过不可分辨关系找出内在规律性，很适合做属性的约简。可辩识矩阵为属性约简提供了一个浓缩了的属性区分信息，可以方便求到核属性，但对于矩阵中除核属性之外的其他属性组合的研究却不容易。熵是概率统计方法中一个概念，概率性的知识提供了一种度量。本文就是基于粗糙集的理论，运用可辨识矩阵，结合信息熵思想，提出一种属性约简算法，保证约简效果与速度。     

基于程度不可区分关系的粗糙集模型

不可区分关系是粗糙集理论的基础。针对信息系统,提出了程度不可区分关系的概念来刻画信息系统中对象的可区分性程度的差异。提出了基于程度不可区分关系的粗糙集模型,并讨论了模型的基本性质,最后研究了基于程度不可区分关系的粗糙近似算子与Pawlak近似算子的关系。     

基于分明矩阵方法的属性约简方法

属性约简和核是粗糙集理论研究的核心内容,进过约简后的数据更有价值.文中详细介绍了A.Skowron基于分明矩阵的属性约简算法,并对此方法进行了简化,以及利用生成的分明矩阵的方法如何求核集和约简的一种方法.     

一种不完备决策表的差别矩阵求核算法

计算不完备决策表的核属性是粗糙集理论的重要内容之一。目前关于不完备决策表的求核算法的研究相对较少,而且在一般的求核算法中,其时间复杂度为[O(|C||U|2)]。为了有效地降低算法的时间复杂度,给出了一个不完备决策表的差别矩阵定义和基于差别矩阵的核定义,并证明了该定义与基于不完备决策表的核定义是等价的。在此基础上,利用差别矩阵方法来设计一种计算不完备决策表的求核算法,其时间复杂度降为[O(|C||Upos||U|)]。最后用仿真实例说明了新算法的有效性。     

基于邻域辨识矩阵的属性约简增量式算法

邻域粗糙集模型可以直接处理连续型数据.属性约简是邻域粗糙集模型的重要研究内容之一.目前已有的增量式粗糙集约简算法主要考虑经典的粗糙集模型的情况,不适用于邻域粗糙集模型.为此,提出一种基于邻域辨识矩阵的属性约简增量式算法,主要考虑连续型数据对象动态增加的情况下的属性约简问题.为了解决该问题,提出了一种邻域决策系统的辩识矩阵,通过辨识矩阵的动态更新实现动态求核,并在此基础上,利用原有的属性约简进行属性约简的更新.     

一种基于不完备决策表的求核方法

求核是粗糙集理论的重要研究内容之一,现有的求核算法大部分都是基于完备决策表的,对基于不完备决策表的求核研究很少。提出了不完备决策表二进制差别矩阵的构造方法,在此基础上,利用二进制差别矩阵设计了一种不完备决策表的求核算法。从理论上证明了基于二进制差别矩阵的求核与基于正区域的求核是相等的。新算法的时间复杂度是[O(|C||U|2)],用实例分析说明了新算法的正确性。     

Three-Link Mechanism as a Model of a Person on a Swing

Journal of Computer and Systems Sciences International - We model movements of a person swinging on a swing. We consider a flat three-link hinged mechanism as the main mechanical model of the...     

On a nonlinear problem of a sequential control with a parameter

The problem of evasion of a group of moving points from a nonlinear controlled object, whose goal is consecutively approach these points in a prescribed order, is analyzed. The movement of each point is defined uniquely by a scalar parameter chosen at the initial time instant. The controlled object minimizes a certain cost function, and the group of the points, acting cooperatively, maximize this cost function by choosing the parameters. Necessary optimality conditions for parameters are obtained. A model problem of an evasion of moving points from a vehicle is solved.     

Splitting a configuration in a simplex

This paper presents a new method of partition, named-splitting, of a point set ind-dimensional space. Given a pointG in ad-dimensional simplexT, T(G;i) is the subsimplex spanned by G and the ith facet ofT. LetS be a set ofn points inT, and let be a sequence of nonnegative integers ₁, ..., n_d+1 satisfying _i=1 ^d+1 ₁=n The-splitter of (T, S) is a pointG inT such thatT(G;i) contains at least _i points ofS in its closure for everyi=1, 2, ...,d + 1. The associated dissection is the re-splitting.The existence of a-splitting is shown for any (T, S) and, and two efficient algorithms for finding such a splitting are given. One runs inO(d²n logn + d³n) time, and the other runs inO(n) time if the dimensiond can be considered as a constant. Applications of re-splitting to mesh generation, polygonal-tour generation, and a combinatorial assignment problem are given.     

Combining a monad and a comonad

We give a systematic treatment of distributivity for a monad and a comonad as arises in giving category theoretic accounts of operational and denotational semantics, and in giving an intensional denotational semantics. We do this axiomatically, in terms of a monad and a comonad in a 2-category, giving accounts of the Eilenberg–Moore and Kleisli constructions. We analyse the eight possible relationships, deducing that two pairs are isomorphic, but that the other pairs are all distinct. We develop those 2-categorical definitions necessary to support this analysis.     

Not a castaway but a stowaway

A portable keyboard that's no larger than my phone, that's theiGo Stowaway.     

Building a sonar map in a specular environment using a singlemobile sensor

The physical properties of acoustic sensors are exploited to obtain information about the environment for sonar map building. A theoretical formulation for interpreting the sensor databases on the physical principles of acoustic propagation and reflection is presented. A characterization of the sonar scan that allows the differentiation of planes, corners, and edges in a specular environment is described. A single sensor mounted on an autonomous vehicle in a laboratory verifies the technique. The implications for sonar map building and the limitations of differentiating elements with one sensor are discussed     

Motion control of a rotor with a cavity with a viscous fluid

A formulation and solution procedure of optimal control problems for perturbed relative uniform motion of a body with a cavity filled with a viscous incompressible fluid are proposed. In this paper, the case with a cylinder is considered; however, this approach is basically true for the a cavity of an arbitrary form. The formula for the angular velocity of perturbed motion depending on an external perturbing element is devised. After that, we have a possibility to set different optimal control problems and apply the formalism elaborated in the optimal control theory. Two illustrated problems are given.