一类供应链中考虑公平关切的学习效应行为实验研究

大量经济学实验研究证实了公平关切和学习效应对决策者行为的影响力。本文研究三人组供应链系统,通过区别设计个体自我学习以及社会学习的实验环境,对比考察备用供应商的公平关切程度,以及制造商和备用供应商学习曲线的特点。实验结果支持了学习效应存在的假设:随着实验期数的增加,单期决策时间逐渐减少,备用供应商的整体拒绝率逐渐降低,制造商的策略逐渐集中。进一步构建了引入公平关切的强化学习模型。通过参数估计发现在个体自我学习和社会学习实验环境下,备用供应商的横向公平关切程度均较为显著,信息共享对备用供应商的横向公平关切偏好无明显影响。     

分权竞争、协同意愿与城市群建设:考虑公平偏好的委托代理解释

互惠合作机制缺失和信息不对称影响了地方政府的区域协调投入,不利于城市群建设和经济高质量发展。在委托代理模型中引入公平偏好的基础上,重点讨论协作意愿和信息条件对努力水平的影响。发现公平偏好和信息条件都对代理人的努力水平产生影响,且代理人之间的信息分布更重要。地方政府努力水平依赖于相邻城市的协同意愿,满足公平偏好中的“互惠”行为;且信息对称情形下的努力水平均高于不对称情形。改善信息分布和引导公平偏好,有利于提高地方政府的区域协同投入而改善整体产出水平。城市群建设和区域协调发展需要健全的协调机制,以增强不同区域地方政府的互信水平和互惠机制,降低、消除区域间信息不对称情形,通过互惠性合作和投入提升区域经济效率、促进经济高质量发展。     

Locality of reference and the use of sojourn time variance for measuring queue unfairness

Sojourn time variance is widely used as an indication of queue unfairness. We demonstrate that this quantity has a disadvantage, since it is not local to the busy period in which it is measured. We show that RAQFM, a recently proposed queue fairness metric, does possess such a locality property.     

Discovering causes and effects of a given node in Bayesian networks

Causal relationships among variables can be depicted by a causal network of these variables. We propose a local structure learning approach for discovering the direct causes and the direct effects of a given target variable. In the approach, we first find the variable set of parents, children, and maybe some descendants (PCD) of the target variable, but generally we cannot distinguish the parents from the children in the PCD of the target variable. Next, to distinguish the causes from the effects of the target variable, we find the PCD of each variable in the PCD of the target variable, and we repeat the process of finding PCDs along the paths starting from the target variable. Without constructing a whole network over all variables, we find only a local structure around the target variable. Theoretically, we show the correctness of the proposed approach under the assumptions of faithfulness, causal sufficiency, and that conditional independencies are correctly checked.     

消费者公平偏好对制造商开通直销渠道的影响研究

研究了消费者公平偏好对制造商开通直销渠道的影响,并分析消费者公平偏好对制造商和零售商的最优决策、制造商开通直销渠道意愿、零售商利润、以及消费者剩余等的影响。最后通过算例分析消费者公平偏好对制造商开通直销渠道意愿的影响。研究发现:不存在消费者公平偏好时,制造商仅在直销成本较小时开通直销渠道;当直销成本较大时,制造商不应开通直销渠道。然而,消费者公平偏好会降低制造商开通直销渠道的意愿;即使无直销成本,若消费者公平偏好较大,制造商也可能不会开通直销渠道。     

Finitary Topos for Locally Finite,Causal and Quantal Vacuum Einstein Gravity

The pentalogy (Mallios, A. and Raptis, I. (2001). International Journal of Theoretical Physics 40, 1885; Mallios, A. and Raptis, I. (2002). International Journal of Theoretical Physics 41, 1857; Mallios, A. and Raptis, I. (2003).International Journal of Theoretical Physics 42, 1479; Mallios, A. and Raptis, I. (2004). ‘paper-book’/research monograph); I. Raptis (2005). International Journal of Theoretical Physics (to appear)is brought to its categorical climax by organizing the curved finitary spacetime sheaves of quantumcausal sets involved therein, on which a finitary (:locally finite), singularity-free, background manifold independent and geometrically prequantized version of the gravitational vacuum Einstein field equations were seen to hold, into a topos structure . We show that the category of finitary differential triads is a finitary instance of an elementary topos proper in the original sense dueto Lawvere and Tierney. We present in the light of Abstract Differential Geometry (ADG) a Grothendieck-type of generalization of Sorkin’s finitary substitutes of continuous spacetime manifoldtopologies, the latter’s topological refinement inverse systems of locally finite coverings and their associated coarse graining sieves, the upshot being that is also a finitary example of a Grothendieck topos. In the process, we discover that the subobject classifier Ω _fcq of is a Heyting algebra type of object, thus we infer that the internal logic of our finitary topos is intuitionistic, as expected. We also introduce the new notion of ‘finitary differential geometric morphism’ which, as befits ADG, gives a differential geometric slant to Sorkin’s purely topological acts of refinement (:coarse graining). Based on finitary differential geometric morphisms regarded as natural transformations of the relevant sheaf categories, we observe that the functorial ADG-theoretic version of the principle of general covariance of GeneralRelativity is preserved under topological refinement. The paper closes with a thorough discussion of four future routes we could take in order to further develop our topos-theoretic perspective on ADG-gravity along certain categorical trends in current quantum gravity research. PACS numbers: 04.60.-m, 04.20.Gz, 04.20.-q Posted at the General Relativity and Quantum Cosmology (gr-qc) electronic archive (www.arXiv.org), as: gr-qc/0507100.     

A General Metric for the Similarity of Both Stochastic and Deterministic System Dynamics

Many problems in the study of dynamical systems—including identification of effective order, detection of nonlinearity or chaos, and change detection—can be reframed in terms of assessing the similarity between dynamical systems or between a given dynamical system and a reference. We introduce a general metric of dynamical similarity that is well posed for both stochastic and deterministic systems and is informative of the aforementioned dynamical features even when only partial information about the system is available. We describe methods for estimating this metric in a range of scenarios that differ in respect to contol over the systems under study, the deterministic or stochastic nature of the underlying dynamics, and whether or not a fully informative set of variables is available. Through numerical simulation, we demonstrate the sensitivity of the proposed metric to a range of dynamical properties, its utility in mapping the dynamical properties of parameter space for a given model, and its power for detecting structural changes through time series data.     

基于公平关切的网络零售商店内推介策略研究

研究了公平关切下网络零售商店内推介策略选择问题。首先,以无公平关切模型为基准,发现无公平关切情形下两零售商均采取推介策略。其次,考虑跟随者(零售商2)公平关切,发现在信息不对称情况下,随着零售商2公平关切程度的增大均衡推介策略依次为:都不推介、仅跟随者(零售商2)推介和都推介,由于信息的不对称公平关切能够诱导跟随者采取推介策略;在信息对称情况下,随着公平关切程度的增大均衡推介策略依次为:仅领导者(零售商1)推介和都推介,信息的透明化能够促使领导型零售商采取推介策略。最后,分析了两零售商都公平关切情形下均衡推介策略选择问题。     

中国中部规模养殖沼气工程系统顶点赋权图分析

基于系统动力学反馈分析理论,提出定性与定量紧密结合的系统顶点赋权因果关系图分析法。以萍乡地区兰坡村泰华猪场规模养殖沼气工程系统为实例,对我国中部农村生猪养殖沼气工程系统的利润、粪尿等废弃物二次生物质再生能源开发、沼肥对水稻和蔬菜种植促进的正效益以及过剩招气对大气的污染、沼液与灌溉用水混合排灌造成水稻苗发青、由于承载沼肥的农田不足和长达七个月的冬闲季节沼肥浪费引发的二次污染等问题进行定量动态反馈分析研究,得出系统蕴含的四条增长、四条制约反馈环的反馈规律。给出针对我国中部地区小流域地域特征的,有利于规模养殖系统可持续发展的沼气工程系统建设的三条对策建议。     

Simultaneous Maximum Likelihood Estimation for Piecewise Linear Instrumental Variable Models

Analysis of instrumental variables is an effective approach to dealing with endogenous variables and unmeasured confounding issue in causal inference. We propose using the piecewise linear model to fit the relationship between the continuous instrumental variable and the continuous explanatory variable, as well as the relationship between the continuous explanatory variable and the outcome variable, which generalizes the traditional linear instrumental variable models. The two-stage least square and limited information maximum likelihood methods are used for the simultaneous estimation of the regression coefficients and the threshold parameters. Furthermore, we study the limiting distribution of the estimators in the correctly specified and misspecified models and provide a robust estimation of the variance-covariance matrix. We illustrate the finite sample properties of the estimation in terms of the Monte Carlo biases, standard errors, and coverage probabilities via the simulated data. Our proposed model is applied to an education-salary data, which investigates the causal effect of children’s years of schooling on estimated hourly wage with father’s years of schooling as the instrumental variable.