Evolving densities in continuous strategy games through particle simulations

Many cases of strategic interaction between agents involve a continuous set of choices. It is natural to model these problems as continuous space games. Consequently, the population of agents playing the game will be represented with a density function defined over the continuous set of strategy choices. Simulating evolutionary dynamics on continuous strategy spaces is a challenging problem. The classic approach of discretizing the strategy space is ineffective for multidimensional strategy spaces. We present a principled approach to simulation of adaptive dynamics in continuous space games using sequential Monte Carlo methods. Sequential Monte Carlo methods use a set of weighted random samples, also named particles to represent density functions over multidimensional spaces. Sequential Monte Carlo methods provide computationally efficient ways of computing the evolution of probability density functions. We employ resampling and smoothing steps to prevent particle degeneration problem associated with particle estimates. The resulting algorithm can be interpreted as an agent based simulation with elements of natural selection, regression to mean and mutation. We illustrate the performance of the proposed simulation technique using two examples: continuous version of the repeated prisoner dilemma game and evolution of bidding functions in first-price closed-bid auctions.     

稠油降粘剂降粘效果测定标准的探讨

叙述了降粘剂的作用机理以及目前测定降粘效果的方法的现状;讨论了对测定降粘效果的温度控制、原油取样控制、加药浓度控制等条件的原由;分析了测定用粘度计的选择及降粘效果的表示与确定.认为,应统一降粘剂效果测定标准,按照SY/T0520-93%测定稠油降粘剂粘度.     

权力平等分配是否有利于家族代理效率提升——家族控制、内部股权集中度与代理效率研究

家族企业的两类代理问题是家族企业区别于其他类型企业的特色之一。文章以深市上市家族企业为研究对象,对家族控制权与代理效率之间的关系,以及股权在家族成员之间的配置中的调节作用进行了实证研究。结果表明,控制性家族对企业控制权的增强有助于提高代理效率。内部股权集中度对家族控制权与代理效率之间的关系起到了显著正向调节作用,这表明家族控制权在内部权力分配集中的阶段对代理效率的贡献更强;另一方面也说明家族内部权力分配的不平等性并不一定会损害家族企业的治理效率,对于家族控制权更高的企业,适度的权力集中分配会对家族企业的发展提供有效的支持。     

基于Agent-人元模型的铁路货运站布局调整方法

为了解决我国铁路货运站数量过多、布局过密、难以产生规模效应等问题,借鉴经典的糖域(Sugarscape)模型,将Agent的智能性和人元模型中主客观属性综合考虑的特性相结合,建立了基于Agent-人元模型的铁路货运站布局模型。该模型将货主视为自主Agent,将货运站作为资源,Agent在寻求资源的过程中能量会发生变化,并根据自己的能量多少来引起货运站价值的变化。按照模型中设定的规则,对该模型进行了仿真分析,得到了一定范围内的货运站布局方案。从仿真结果可以看出,该模型将所研究的车站划分成保留站、待定站和取消站三类,这对于货运站布局优化以及战略装车点的设置具有指导性意义。     

企业自主创新中个人知识利用策略研究

自主创新需要多个领域专家的参与,充分利用参与者所掌握的知识是自主创新取得成功的保障。使用委托代理模型分析了个人参与自主创新贡献其知识的努力水平、自主创新岗位工资、企业对监督的投入、个人工作时间之间的相互关系。在此基础上,提出了企业自主创新中的个人知识利用策略。     

国企锦标赛激励效应与制约因素研究

本文尝试从锦标赛的角度为国企竞争理论提供信息经济学模型解释和实证支持。为了达到这一目的,本文从政府干预和共同代理的角度对经典的锦标赛模型进行细化和拓展,以揭示出国企锦标赛激励效应与制约因素,并收集2451家地方国有上市公司披露的薪酬差距数据对理论模型进行实证检验。理论模型表明,薪酬差距的扩大和国企经营者赢得经济锦标赛激励的强化会增加国企经营者的努力水平,因而有利于公司绩效的提升。不过,国企经营者赢得经济锦标赛的激励却受到政府行政干预和共同代理问题的制约。实证结果表明,我国地方国有上市公司薪酬差距与公司绩效显著正相关,而与地方政府行政干预和共同代理问题的严重程度显著负相关,从而支持了理论模型。     

Cycles,determinism and persistence in agent-based games and financial time-series: part II

The present article constitutes part II of a series of two reports in which we study the decomposition of synthetic and real financial time-series into a superposition of weighted Hamiltonian cycles on graphs. Part II further analyses the cycle-decomposition method introduced in part I for the Minority Game (MG), the Majority Game (MAJG) and the Dollar Game ($G), in order to gain insight into the ‘illusion of control’ that certain of these games demonstrate, i.e. the fact that the strategies outperform the agents that deploy them. We also illustrate both numerical and analytical methods for extracting cycles from a given time-series and apply the method to a number of different real-world data sets, in conjunction with an analysis of persistence.     

Econophysics review: II. Agent-based models

This article is the second part of a review of recent empirical and theoretical developments usually grouped under the heading Econophysics. In the first part, we reviewed the statistical properties of financial time series, the statistics exhibited in order books and discussed some studies of correlations of asset prices and returns. This second part deals with models in Econophysics from the point of view of agent-based modeling. Of the large number of multi-agent-based models, we have identified three representative areas. First, using previous work originally presented in the fields of behavioral finance and market microstructure theory, econophysicists have developed agent-based models of order-driven markets that we discuss extensively here. Second, kinetic theory models designed to explain certain empirical facts concerning wealth distribution are reviewed. Third, we briefly summarize game theory models by reviewing the now classic minority game and related problems.     

Disentangling and quantifying market participant volatility contributions

Thanks to the access to labeled orders on the CAC 40 index future provided by Euronext, we are able to quantify market participants contributions to the volatility in the diffusive limit. To achieve this result, we leverage the branching properties of Hawkes point processes. We find that fast intermediaries (e.g. market maker type agents) have a smaller footprint on the volatility than slower, directional agents. The branching structure of Hawkes processes allows us to examine also the degree of endogeneity of each agent behavior, and we find that high-frequency traders are more endogenously driven than other types of agents.     

An agent-based nurse rostering system under minimal staffing conditions

Nurse rostering is a complex problem. We propose a new heuristic using a competitive agent-based negotiation that focuses on nurse preferences called competitive nurse rostering (CNR). Unlike the existing literature, CNR models each nurse's preference functions separately and separates the cost minimization and preference maximization problems. CNR produces quality nurse rosters even though it cannot leverage extra staffing. As an agent system, CNR can distribute computational requirements over several computer systems, include other solution methods at various points in of the rostering problem, and act as a real-time scheduling system. These benefits are not naturally inherent in centralized heuristic solutions.