首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
次微分意义下集值映射优化问题的最优性条件   总被引:1,自引:4,他引:1  
在实赋范空间中,研究集值向量优化问题解的最优性条件。给出了锥凸集值映射次梯度和次微分的概念,通过锥凸集值映射的上图象的条件锥定义了锥凸集值映射的条件上导数,研究了次微分的性质。在次微分意义下,获得了集值映射优化的弱极小元的最优性条件。  相似文献   

2.
研究了一类带二次等式约束的二次规划问题,利用求非凸优化问题全局最优性条件的一个新方法-L-次微分方法(与凸分析中的概念不同,一个函数在某点的L-次微分可能是一些非线性函数组成的集合),对二次函数的L-次微分进行了刻画,最后建立带二次等式约束非凸二次极小化规划问题的全局最优化的一个充分条件.  相似文献   

3.
本文考虑带有不等式约束二次规划问题.通过拉格朗日函数、L 次微分和L 正则锥相结合的方法给出了带有不等式约束二次规划问题的全局最优性充分条件. 本文的一些结果与已有文献中的一些结论是一致的,而在一定的条件下则推广了已有文献中的一些结论. 最后通过实例说明了本文给出的全局最优性充分条件的可行性、有效性和优越性.  相似文献   

4.
全局最优性条件是判断一个解是否为全局最优解的基本条件,在此前,已经有文献提出了非凸二次规划问题和非凸三次次规划问题的充分全局最优性条件,但是均未对六次规划问题进行研究.因此,本文利用L-次梯度方法,得到了带有箱子约束的非凸六次规划问题的全局最优充分性条件.此外,通过构造一类特殊的对角矩阵,以方便验证所提出问题的全局充分性条件.  相似文献   

5.
利用一些学者提出的一种研究全局最优化问题的全局最优性条件的新方法,讨论了一些带有二次约束的非凸二次规划问题的全局最优性条件.本文主要通过利用拉格朗日函数Fλ,u=1/2xTHλ,ux+bTλ,ux+∑I∈Iλici+∑j∈Jμjcj,正则锥(NL,D(x0)={l∈L:l(y)-l(x0)≤0,()y∈D})和L-次微分相结合的方法,给出了带不等式约束的混合整数二次规划最小问题的全局极小点的全局最优性充分条件,而且推广了现有文献中的一些结论.同时通过一些实值例子说明了本文给出的最优性充分条件的可行性和有效性.  相似文献   

6.
局部最优性必要条件是用来设计局部优化算法的一个主要工具。本文将介绍求解全局优化问题的一种新的方法:利用全局景优性器件(最优性必要备件[NC]和最优性充分备件[SC])来研究一类{0,1}双值混合二次规划问题的一些最优化算法。首先利用其全局最优性必要条件[NC]来研究这类双值混合二次规划问题的局部最优化算法,然后针对于这类{0,1}双值混合二次规划问题,研究一类特殊的辅助函数Fr,x(x)来克服现有的局部极小点,最后利用所碍到的辅助函数Fr,x(x)和局部优化算法LOMMQP以及全局最冼性充分条件[SC]来得到具有一定终止准则的全局最优化算法(GOM)。  相似文献   

7.
本文讨论相依上图导数形式下广义弧连通锥-凸集值优化近似解的最优性条件问题.首先,本文引入次弧连通锥-凸集值映射的概念,并举例说明次弧连通锥-凸性是弧连通锥-凸性的推广;其次,得到了次弧连通锥-凸集值映射的两个有用性质;最后,在次弧连通锥-凸性条件下,分别建立了集值优化问题强近似极小元和弱近似有效元的充分最优性条件.  相似文献   

8.
在锥序Banach向量空间引入了集值映射次微分(次梯度),在一定的条件下,证明次微分(次梯度)的存在性及它的一些性质;得到了集值优化问题严有效点集在次微分意义下的稳定性.  相似文献   

9.
利用拉格朗日函数和L-次微分的方法,研究了带有二次约束的一类特殊三次规划问题的全局最优性条件。首先刻画出该类三次规划问题的拉格朗日函数的抽象次微分,从而得到了带有二次约束的三次规划问题的全局最优性充分条件。最后举例说明如何利用本文所给出的全局最优性充分条件来判定当前可行解就是全局最优解。
  相似文献   

10.
在Hausdorff局部凸拓扑线性空间中考虑集值优化的ε-严有效性,当目标函数和约束函数构成的序偶映射是近似锥-次类凸时,在较弱的约束品性假设下,借助凸集分离定理得到了集值优化ε-严有效解的Lagrange型最优性条件.  相似文献   

11.
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   

12.
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  相似文献   

13.
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.  相似文献   

14.
15.
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.  相似文献   

16.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

17.
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。  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号