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1.
赵华  冯德成 《数学杂志》2002,22(2):185-190
本文引入了条件(wp),研究了其性质,建立了它与弱平坦性之间的联系,并利用其给出了某些幺半群的S-系范畴特征。  相似文献   

2.
研究了条件(Q)、条件(PT)对推出图、Rees商的传递性,证明了在推出图(1)中P满足条件(Q)当且仅当Y满足条件(Q)并且f是酉的.  相似文献   

3.
A traveling mass due to its mass inertia has significant effects on the dynamic response of the structures. According to recent developments in structural materials and constructional technologies, the structures are likely to be affected by sudden changes of masses and substructure elements, in which the inertia effect of a moving mass is not negligible. The transverse inertia effects have been a topic of interest in bridge dynamics, design of railway tracks, guide way systems and other engineering applications such as modern high-speed precision machinery process. In this study an analytical–numerical method is presented which can be used to determine the dynamic response of beams carrying a moving mass, with various boundary conditions. It has been shown that the Coriolis acceleration, associated with the moving mass as it traverses along the vibrating beam shall be considered as well. Influences regarding the speed of the moving mass on the dynamic response of beams with various boundary conditions were also investigated. Results illustrated that the speed of a moving mass has direct influence on the entire structural dynamic response, depending on its boundary conditions. Critical influential speeds in the moving mass problems were introduced and obtained in numerical examples for various BC’s.  相似文献   

4.
This article employs new data envelopment analysis/assurance region (DEA/AR) methods to evaluate the efficiency of the 35 textile factories of the Nanjing Textiles Corporation (NTC), Nanjing, China. The returns to scale (RTS) of these factories were studied without assuming that the optimal DEA solutions were unique. All DMUs are identified with pointsE (Extreme Efficient),E (Efficient but not an extreme point) andF (Frontier but not efficient). We then further identify the nonfrontier DMUs with pointsNE, NE andNF according to whether they are projected onto a point inE, E, orF en route to evaluating their performances. All of the inefficient factories were in classNF and had unique optimal primal-dual solution pairs. Consequently, the solution pairs satisfy the strong complementary slackness condition (SCSC). Application of cone-ratio (CR) ARs reduced significantly the number of factories in classE, and showed that some AR-efficient factories were more flexible in adopting the mixture of central planning and market economies that China currently is trying to use. Also, linked-cone (LC) ARs were applied to measure maximum and minimum profit ratios. The SCSC multiplier space approach was utilized to analyze the sensitivity of the efficiency results to potential errors in the data with and without ARs. The results in this article suggest that collective units had a better performance than state-owned units in the two consecutive years analyzed.This paper was written while the author was at the School of Economics and Management, Southeast University, Nanjing 210018, P.R. China.  相似文献   

5.
运用临界点理论中的极小极大方法,得到了一类次二次位势条件和半强制条件下的二阶哈密尔顿系统的周期解的存在性,改进了某些已有的结果.  相似文献   

6.
本研究采用数量化方法(Ⅰ)来确定花样游泳运动员身体条件优劣的鉴别标准使这项鉴别工作客观化、计量化。研究结果给出的“我国花样游泳运动员身体条件优劣鉴别表”形式简单明了,便于在实际工作中使用  相似文献   

7.
8.
运用极小极大方法得到一类局部非二次的Hamilton系统的次调和解的存在性定理.  相似文献   

9.
In this article, we prove some strong and weak convergence theorems for quasi-nonexpansive multivalued mappings in Banach spaces. The iterative process used is independent of Ishikawa iterative process and converges faster. Some examples are provided to validate our results. Our results extend and unify some results in the contemporary literature.  相似文献   

10.
Let R be a noncommutative prime ring, U be the left Utumi quotient ring of R, and k, m, n, r be fixed positive integers. If there exist a generalized derivation G and a derivation g (which is independent of G) of R such that [G(xm)xn + xng(xm), xr]k = 0, for all x ∈ R, then there exists a ∈ U such that G(x) = ax, for all x ∈ R. As a consequence of the result in the present article, one may obtain Theorem 1 in Demir and Argaç [10 Demir, Ç., Argaç, N. (2010). A result on generalized derivations with Engel conditions on one-sided ideals. J. Korean Math. Soc. 47(3):483494.[Crossref], [Web of Science ®] [Google Scholar]].  相似文献   

11.
In this note, the local spectral properties of unilateral operator weighted shifts arestudied.  相似文献   

12.
In this paper, the exponential stability of singularly perturbed impulsive delay differential equations (SPIDDEs) is concerned. We first establish a delay differential inequality, which is useful to deal with the stability of SPIDDEs, and then by the obtained inequality, a sufficient condition is provided to ensure that any solution of SPIDDEs is exponentially stable for sufficiently small ε>0. A numerical example and the simulation result show the effectiveness of our theoretical result.  相似文献   

13.
In this paper, we study the order of convergence of the Euler-Maruyama (EM) method for neutral stochastic functional differential equations (NSFDEs). Under the global Lipschitz condition, we show that the pth moment convergence of the EM numerical solutions for NSFDEs has order p/2 − 1/l for any p ? 2 and any integer l > 1. Moreover, we show the rate of the mean-square convergence of EM method under the local Lipschitz condition is 1 − ε/2 for any ε ∈  (0, 1), provided the local Lipschitz constants of the coefficients, valid on balls of radius j, are supposed not to grow faster than log j. This is significantly different from the case of stochastic differential equations where the order is 1/2.  相似文献   

14.
本文引入了条件(Pw),讨论了条件(Pw)与条件(P)、条件(PE)之间的关系,刻画了幺半群上S-系的平坦性.  相似文献   

15.
In the face of acute global competition, supplier management is rapidly emerging as a crucial issue to any companies striving for business success and sustainable development. To optimize competitive advantages, a company should incorporate “suppliers” as an essential part of its core competencies. Supplier evaluation, the first step in supplier management, is a complex multi-criteria decision-making (MCDM) problem, and its complexity is further aggravated if the highly important interdependence among the selection criteria is taken into consideration. The objective of this paper is to suggest a comprehensive decision method for identifying top suppliers by considering the effects of interdependence among the selection criteria, as well as to achieve optimal allocation of orders among the selected suppliers.  相似文献   

16.
We prove a common fixed point theorem of Gregus type for four mappings satisfying a generalized contractive condition in metric spaces using the concept of weak compatibility which generalizes theorems of [I. Altun, D. Turkoglu, B.E. Rhoades, Fixed points of weakly compatible mappings satisfying a general contractive condition of integral type, Fixed Point Theory Appl. 2007 (2007), article ID 17301; A. Djoudi, L. Nisse, Gregus type fixed points for weakly compatible mappings, Bull. Belg. Math. Soc. 10 (2003) 369-378; A. Djoudi, A. Aliouche, Common fixed point theorems of Gregus type for weakly compatible mappings satisfying contractive conditions of integral type, J. Math. Anal. Appl. 329 (1) (2007) 31-45; P. Vijayaraju, B.E. Rhoades, R. Mohanraj, A fixed point theorem for a pair of maps satisfying a general contractive condition of integral type, Int. J. Math. Math. Sci. 15 (2005) 2359-2364; X. Zhang, Common fixed point theorems for some new generalized contractive type mappings, J. Math. Anal. Appl. 333 (2) (2007) 780-786]. We prove also a common fixed point theorem which generalizes Theorem 3.5 of [H.K. Pathak, M.S. Khan, T. Rakesh, A common fixed point theorem and its application to nonlinear integral equations, Comput. Math. Appl. 53 (2007) 961-971] and common fixed point theorems of Gregus type using a strict generalized contractive condition, a property (E.A) and a common property (E.A).  相似文献   

17.
In the paper, we define(inco) project modules of relatively hereditary torsion theory Υ by intersection complement of module and study their properties; secondly, we define the(inco) Υ-semisimple ring by(inco) Υ-projective module and study their properties. When Υ is a trivial torsion theory on R-rood, we prove that R is a semisimple ring if and only if R is a(inco) semisimple ring and satisfies(inco) condition.  相似文献   

18.
In this paper we design high-order (non)local artificial boundaryconditions (ABCs) which are different from those proposed byHan, H. & Bao, W. (1997 Numer. Math., 77, 347–363)for incompressible materials, and present error bounds for thefinite-element approximation of the exterior Stokes equationsin two dimensions. The finite-element approximation (especiallyits corresponding stiff matrix) becomes much simpler (sparser)when it is formulated in a bounded computational domain usingthe new (non)local approximate ABCs. Our error bounds indicatehow the errors of the finite-element approximations depend onthe mesh size, terms used in the approximate ABCs and the locationof the artificial boundary. Numerical examples of the exteriorStokes equations outside a circle in the plane are presented.Numerical results demonstrate the performance of our error bounds.  相似文献   

19.
在本文中,证明了每一个正关联BCK-代数X均可嵌入于具有条件(S)的正关联BCK-代数X*,且X是X*的一个子代数.特别地,当X是关联时,那么X*也是关联的  相似文献   

20.
Supply chain design is becoming a core competency, and the enterprise resource planning (ERP) system is expected to be an integral component of supply chain management (SCM). Installing an ERP system is, however, expensive and risky. IT managers must decide how to use their limited resources and invest in the right product. Can an ERP system directly improve SCM competency? This study proposes a conceptual framework featuring the ERP benefits and SCM competencies, and examines the impacts of the former on the latter. The results confirm the operational, managerial, and strategic benefits of ERP for the SCM competencies, but not the IT infrastructure and organizational benefits as significant predictors of them. Moreover, more than 80% of respondents think it necessary to first adopt an ERP system as the backbone of company operations before deploying other enterprise systems (ES), such as the SCM system.  相似文献   

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