蚁群算法在物流配送路径优化问题上的应用

物流配送路径优化是现代物流配送服务的关键环节之一,需要一个快速而有效的求解算法,构建了物流配送路径优化问题的数学模型,并应用蚁群算法加以求解。在模拟试验基础上,得出了蚁群算法对物流配送路径优化问题十分有效的结论,探索出了一条高效求解物流配送路径优化问题的新途径。     

农村人力资本投资及外溢与城乡差距实证研究

文章以人力资本溢出效应城乡两区域模型为基础,采用协整检验和误差修正模型,对中国农村人力资本投资及外溢与城乡差距的关系进行实证检验。结果表明,缩小中国城乡差距,必须加大对农村的人力资本投资。同时,要加强政府对农村的基础设施投资,为农村人力资本作用的充分发挥创造条件。     

Market power in input purchase and trade

Market power in the input purchase is becoming increasingly common because of growing consolidation and mergers and also due to multinational firms establishing a stronghold in buying inputs in the developing countries. In this study, we formulate a general equilibrium model consisting of a competitive sector and an oligopsony sector which exercises market power over inputs. Our results indicate that if the oligopsony sector incurs a higher marginal factor cost for the intensive factor, basic results of the standard two-sector model continue to hold. But if the marginal factor cost is higher for the non-intensive factor, then factor intensities in the physical and value sense differ and traditional trade propositions such as the Stolper–Samuelson theorem do not hold.     

Evolutionary stability and lexicographic preferences

We explore the interaction between evolutionary stability and lexicographic preferences. To do so, we define a limit Nash equilibrium for a lexicographic game as the limit of Nash equilibria of nearby games with continuous preferences. Nash equilibria of lexicographic games are limit Nash equilibria, but not conversely. Modified evolutionarily stable strategies (Binmore and Samuelson, 1992. J. Econ. Theory 57, 278–305) are limit Nash equilibria. Modified evolutionary stability differs from “lexicographic evolutionarily stability” (defined by extending the common characterization of evolutionary stability to lexicographic preferences) in the order in which limits in the payoff space and the space of invasion barriers are taken.     

Capacity constrained firms in (labor) markets with adverse selection

Summary. We discuss a competitive (labor) market where firms face capacity constraints and individuals differ according to their productivity. Firms offer two-dimensional contracts like wage and task level. Then workers choose firms and contracts. Workers might be rationed if the number of applicants exceeds the capacity of the firm. We show that under reasonable assumptions on the distribution of capacity an equilibrium in pure strategies (by the firms) exists. This result stands in contrast to the case of unlimited capacity. The utility level is uniquely determined in equilibrium. No rationing occurs in equilibrium, but it does off the equilibrium path. Received: December 29, 1999; revised version: November 30, 2000     

Limit-pricing as Bertrand equilibrium

Summary. We consider a Bertrand duopoly model with increasing returns to scale where one of the firms have a cost advantage and prices vary over a grid. We find that typically more than one equilibria exist. However, there are only two perfect equilibria. Moreover, as the size of the grid becomes small, both these equilibria converge to the limit-pricing outcome. Received: February 25, 2000; revised version: January 9, 2001     

Determinacy with nominal assets and outside money

Summary. We build a finite horizon model with inside and outside money, in which interest rates, price levels and commodity allocations are determinate, even though asset markets are incomplete and asset deliveries are purely nominal.Received: 2 July 2003, Revised: 1 December 2004 JEL Classification Numbers: D50, E40, E50, E58.Correspondence to: J. Geanakoplos     

Market clearing and derivative pricing

Summary. We develop a method of assigning unique prices to derivative securities, including options, in the continuous-time finance model developed in Raimondo (2001). In contrast with the martingale method of valuing options, which cannot distinguish among infinitely many possible option pricing processes for a given underlying securities price process when markets are dynamically incomplete, our option prices are uniquely determined in equilibrium in closed form as a function of the underlying economic data.Received: 14 April 2003, Revised: 7 January 2004, JEL Classification Numbers: G13, D52.This paper is dedicated to Birgit Grodal, whose strength and character we greatly admire. We are very grateful to Darrell Duffie, Steve Evans, Botond Koszegi, Roger Purves, Jacob Sagi, Chris Shannon, Bill Zame and an anonymous refereee for very helpful discussions and comments. The work of both authors was supported by Grant SES-9710424, and Andersons work was supported by Grant SES-0214164, from the National Science Foundation.     

Extensive-form games and strategic complementarities

I prove the subgame-perfect equivalent of the basic result for Nash equilibria in normal-form games of strategic complements: the set of subgame-perfect equilibria is a nonempty, complete lattice—in particular, subgame-perfect Nash equilibria exist. For this purpose I introduce a device that allows the study of the set of subgame-perfect equilibria as the set of fixed points of a correspondence. My results are limited because extensive-form games of strategic complementarities turn out—surprisingly—to be a very restrictive class of games.     

新国有资产管理体系中国有控股公司的定位与运作探讨

在新的国有资产管理体系中,国有控股公司将被授权成为国有资产具体的出资人代表,成为国资委与国有参股企业之间的一个中介,尽管这并不是新的国有资产管理模式的唯一选择。显然,国有控股公司的有效运作是保证国有资产出资人到位,确保国有资产保值增值的关键环节。本文认为,国有控股公司的有效运作既需要相应的外部条件,也需要合理可行的内部组织管理体系,这包括相对单一的经营目标、相互制衡的治理结构及对参股、控股公司的有效管理方式等。