关于非单位步长的紧优双环网络G(N;r,s)

双环网络是计算机互连网络或通讯系统的一类重要拓扑结构,其图论模型是指一个有向图G(N;r,s):每个顶点记为0,1,2,…,N-1,并从每个顶点I发出两条有向边I→I r(mod N)和I→I s(mod N),其中r和s是自然数,且1≤r≠s＜N.若G(N;r,s)存在k紧优双环网络,G(N;1,s)存在k1紧优双环网络,且满足k1＞k,称G(N;r,s)为非单位步长双环网络.在L形瓦理论的基础上,给出一个求非单位步长双环网络的方法,求得两个关于模型G(N;r,s)的紧优双环网络无限族;结合中国余数定理和数论中的素数理论,给出一个求非单位步长双环网络无限族(k1-k≥1且k＞0)的方法;作为具体应用,求得两个非单位步长双环网络无限族(k1-k≥2且k＞0).     

两类特殊的双环网络无限族

双环网络是计算机互连网络或通讯系统的一类重要拓扑结构。文中推广了徐俊明等人的主要结论，给出两类特殊的双环网络无限族构造方法，解决了陈宝兴等人提出的两个关于紧优双环网络无限族的问题，从而得到若干类3紧优双环网络无限族。最后给出一类非单位步长双环网络无限族（k1-k≥5）和一个非单位步长5紧优双环网络无限族（k1-k=5）。     

奇异k-紧整数无限族

设n，s1，s2是3个正整数，使得s1〈s2〈n，gcd（n，s1，s2）=1．双环网G（n；s1，s2）是个有向图，其结点集为V={0，1，2，…，n-1}，其弧集为A={i→i＋s1 （mod n），i→i＋s2（mod n）｜i∈V}，s1和s2称为步长．设d（n；s1，s2）为双环网G（n；s1，s2）的直径．令 d（n）=min{d（n；s1，s2）｜s1〈s2〈n}，d1（n）=min{d（n；1，s）｜1〈s〈n）． 已知d1（n）≥d（n）≥｜√3n｜-2=lb（n）．若d（n；s1，s2）=d（n）=lb（n）＋k（k≥0），则称G（n：s1，s2）是个k-紧优的双环网．虽然等式d1（n）=d（n）对于无限多个整数n成立，但也存在无限多个整数n使得d1（n）〉d（n），这样的n称为奇异整数．若d1（n）〉d（n）=lb（n）十k，k≥0，则这样的n称为奇异k-紧整数． 本文给出构造奇异k-紧整数无限族的方法，并对于k=1,2．…．20，构造出这样的无限族．     

双环网络的多项式无限族

给出一些紧优的G（N；±1，±s）无限族，其中s均为一元二次多项式，还给出求一般双环网络多项式无限族的方法及若干具体应用。     

关于有向双环网络L-形瓦的四个参数

对于有向双环网络G（n；s1，s2），四个参数k1，k2，j1,j2定义如下： （1）k1=min（k1ks2=js1（mod n）且k≥j≥0,k=1,2,…,n-1）； （2）j1=min（j1k1s2=js1（mod n）,j≥0）; （3） j2=min（j1 ks2=js1（mod n）且j〉k≥0,j=1,2,…,n=1）; （4）k2=min（k1 ks2=j2s1（mod n）,k≥0） 则k1，k2，j1,j2恰好是由G（n；s1，s2）决定的L-形瓦的四个参数，并且（j2-j1，k1-k2）是同余方程xs1＋ys2=0（mod n）的最小正解．     

关于k紧优双环网络

给出了判断N个节点存在k(k≥0)紧优双环网络的一个算法,得到该算法的复杂性为O(N1/4).作为具体应用,给出一个7紧优双环网络的无限族.首次给出了一个7紧优双环网络G(81 190 689;16 035),其直径为15 612.     

奇异k紧优双环网络无限族的构造

提出构造任意奇异k紧优双环网络无限族的一种方法.对于整数k>1/2m+(3+(2i-1)2)/24,m≥(i-i2-1)/3,设N(t)=3t2+(2i-1)t+B,其中B=k2+k-m,1≤i≤3且N(t)∈Ii(t),证明了对于若干组i和m,可以构造奇异k紧优双环网络无限族.     

一种新的紧优双环网络无限族构造方法

提出一种新的紧优双环网络无限族的构造方法.该方法从一个具体的不含k(0≤k≤m)紧优双环网络的N0出发,通过求一个同余方程方程组的所有解,构造不含k(0≤k≤m)紧优双环网络的无限族.从一个具体的可实现L形瓦出发,利用其h和y互素条件,构造可实现L形瓦的无限族.作为应用,给出若干7紧优和8紧优双环网络无限族;解决了几个关于紧优双环网络无限族的公开问题.     

基于圈的紧优双环网络G(N;1,s)求解算法

提出基于圈的紧优双环网络G(N；1，s)求解算法，利用VB6．0作为编程语言、SQL Server 2000作为数据库来实现这一算法，对任意给定N，而2≤s≤N-1的这样一族双环网络中的所有紧优双环网络都可以计算出来，结果存入数据库．算出N≤200的所有紧优双环网络。     

无向双环网络G(N;±r,±s)直径求解方法

提出新的无向双环网络G(N;±r,±s)的直径求解法———分步法;并得到一种新的直观图———螺旋环,研究了螺旋环的性质;给出了无向双环网络的直径d(N;±r,±s)的显式公式;给出了N,s都固定的直径算法;在N固定,且2≤r相似文献   

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.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

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.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme