SSC的共享天堂

随着企业不断的发展和分支机构不断的增加,众多重复设置的职能机构所带来的成本压力是企业寻找新的管理模式的主要动力,而共享服务应是一个可行的选择。共享服务中心源于上世纪80年代的西方发达国家．90年代开始推广21世纪初加快了推广步伐。福特公司是世界公认的第一个设立SSC（Shared Services Center）的企业。上世纪80年代初,它在欧洲第一个设立财务共享服务中心。     

The center and the distance center of a ptolemaic graph

The points of a distance center in a Ptolemaic graph G induce a complete subgraph of G, and the points of a center in a chordal graph constitute a convex.     

Analytic center of spherical shells and its application to analytic center machine

The two-case pattern recognition problem aims to find the best way of linearly separate two different classes of data points with a good generalization performance. In the context of learning machines proposed to solve the pattern recognition problem, the analytic center machine (ACM) uses the analytic center cutting plane method restricted to spherical shells. In this work we prove existence and uniqueness of the analytic center of a spherical surface, which guarantees the well definedness of ACM problem. We also propose and analyze new primal, dual and primal-dual formulations based on interior point methods for the analytic center machine. Further, we provide a complexity bound on the number of iterations for the primal approach. F.M.P. Raupp was partially supported by CNPq Grant 475647/2006-8 and FAPERJ/CNPq through PRONEX-Computational Modeling. B.F. Svaiter was partially supported by CNPq Grants 300755/2005-8, 475647/2006-8 and by FAPERJ/CNPq through PRONEX-Optimization.     

Distribution center consolidation games

We study a location-inventory model to analyze the impact of consolidation of distribution centers on facility and inventory costs. We introduce a cooperative game and show that when demand processes are i.i.d. the core is non-empty, i.e., consolidation allows for a stable division of the minimal costs.     

The nonautonomous function-theoretic center problem

We study the linearizability and stability of a nonautonomous dynamical system in the neighborhood of a neutral fixed point. Our results generalize the classical results of Schröder and Siegel in the case when the linear part of the mapping is an irrational rotation, well known results in the rational case and the fundamental result on the representation of the system as a translation in the neighborhood of a fixed point at infinity.     

Associative rings with large center

A ring R is called a ring with large center if any nonzero ideal of R has nonzero intersection with the center of R. We give some conditions for an ideal of a ring with large center to be itself a ring with large center, and also we provide an example of a ring with large center R and its ideal I ? R such that I is not a ring with large center.     

小波变换与矩心

利用多分辨分析的思想，研究了信号经波波变换后矩心的计算问题。     

Location of rectilinear center trajectories

A rectilinear center trajectory is a polygonal line consisting only of horizontal and vertical segments which minimizes the maximum distance tom given points in the plane. In this paper a polynomial time geometric procedure, to find a center trajectory subject to the number of bends, is presented. When the polygonal is constrained on the extreme segments a modified algorithm is designed.     

The ?-positive center figure

Based on Gage's notion of a “positive center” of a planar convex set, an ε-positive center figure is defined, constructed, and illustrated through example. The existence of an ε-positive center point, and the convexity of the ε-positive center figure, is conjectured.     

The biobjective absolute center problem

This paper deals with the problem of determining the absolute center of a network, taking into account two objective functions. These functions consist of minimizing the maximum of the distances from any point on the network to the vertices, using two independent lengths on each edge. We propose an algorithm in polynomial time to obtain the non-dominated location points on the network, using the Kariv and Hakimi method (1979). This work was partially supported by project number 93/108 from the Dirección General de Universidades e Investigación del Gobierno de Canarias.     

Scheduling of a machining center

A machining center is an advanced NC (Numerical Control) machine that has the capability to perform a variety of operations on a part by automatically changing the cutting tools. Because of its versatile processing capabilities, a machining center is often a production bottleneck, and effective scheduling can result in significant improvement of system performance. The problem, however, is very difficult since many factors such as machine setups, pallets, tool magazine, and possible tool overlapping among different part types, etc., have to be considered. This paper presents an optimization-based approach for the scheduling of a machining center with two pallets. A novel “separable” problem formulation that considers the above mentioned factors is presented. Lagrangian relaxation is applied to decompose the problem into simple subproblems, which are efficiently solved without encountering complexity difficulties. The subgradient method is then used to update the multipliers. Testing results indicate that the approach is effective, and the algorithm provides a valuable tool for solving stand-alone machining center problems. The approach also points out a direction on how to consider machining centers within a job shop environment.     

Chebyshev center based column generation

The classical column generation approach often shows a very slow convergence. Many different acceleration techniques have been proposed recently to improve the convergence. Here, we briefly survey these methods and propose a novel algorithm based on the Chebyshev center of the dual polyhedron. The Chebyshev center can be obtained by solving a linear program; consequently, the proposed method can be applied with small modifications on the classical column generation procedure. We also show that the performance of our algorithm can be enhanced by introducing proximity parameters which enable the position of the Chebyshev center to be adjusted. Numerical experiments are conducted on the binpacking, vehicle routing problem with time windows, and the generalized assignment problem. The computational results of these experiments demonstrate the effectiveness of our proposed method.     

Cancellative semigroups with non-empty center

Cancellative, idempotent-free semigroups having non-empty center are characterized in terms of a Schreier extension. Cancellative pivoted semigroups with non-empty center are characterized as a group or in terms of a triple (G,H,I), where G is a group, H is either empty or a subgroup of G and I is a function mapping GxG into the non negative integers.     

Sources of the center of dilatation and center of compression types in the Biot model

For a homogeneous isotropic model of porous Biot media, wave fields of spherically symmetric point sources are determined. The conditions under which a point source of the center of compression type can be replaced by two sources, one of which is a pair of oppositely directed forces and the other is a center of radially directed tangential forces, are obtained. Bibliography: 9 titles. Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 230, 1995, pp. 196–213. Translated by L. A. Molotkov.     

The center problem via averaging method

The averaging method has been used to study the problem of the determination of the number of hyperbolic limit cycles that can bifurcate from the period annulus of a center. In this paper we use the averaging method up to any order in the perturbation parameter to determine the center conditions of monodromic singular points of analytic planar vector fields.