Assessing Service Level Targets in Production and Inventory Planning*

In production and stock planning, the relationship between customer service, defined as the ability to meet demand for finished goods from in-stock inventory, and expected profits or expected costs can be represented by a simple reliability curve. The shape of this curve depends upon the parameters of the demand process, specifically the expected level of demand, standard deviation and correlation structure, as well as upon the capacities and initial state of the production and inventory system. A model is presented which explicitly determines this trade-off curve for a firm. The model is intended both as an operational model to aid managers in setting revenue and service targets which are compatible with the capacities and resources of the firm, and as a tool for exploring relationships between the parameters of the demand process and the constraints of the physical production and inventory system. The results illustrate that the level of risk depends strongly on the variability of the demand process, the cost structure, the capacities and initial state of the system and, to a lesser extent, the correlation in demand between succeeding periods. Results suggest that establishing service level targets consistent with the firm's strategic orientation must be done in consideration of both the characteristics of the demand process and the capacities of the production and inventory system. The model provides a tool for estimating the premium above unit cost which must be paid to provide a designated service level.     

基于过度自信的交易量驱动因素建模研究

基于信息模型框架引入过度自信假设构建理论模型,在考虑信息结构环境的基础上建立状态依赖过度自信模型,从信息流动机制和微观机理的角度分析市场历史收益和交易量之间的关系。根据理论结果提出了私人信息冲击对交易量具有正向作用以及历史收益和交易量呈正相关的两个假说,随后基于中国证券市场的实证检验进一步验证了相关理论假说的正确性。     

价格持续期、信息传递与市场微观结构——基于非对称ACD模型的实证分析

本文建立两状态价格持续期的非对称对数自回归条件持续期模型,引入买卖价差、交易量、交易规模、指令流等信息交易间接度量变量,在刻画条件期望价格持续期对价格上升和下降两种状态的不对称依赖关系的同时,探讨价格持续期的信息传递机制并检验微观结构相关假说。实证分析表明,在选取样本中,滞后买卖价差与滞后交易量与条件期望价格持续期显著负相关;滞后买一(卖一)指令申报数量与条件期望价格持续期具有显著相关性,其符号由当期价格状态决定;大规模交易比中等规模交易对条件期望价格持续期有着更加显著的影响。即实证结果支持信息交易增加导致交易持续期减小的观点,不支持隐藏交易假说。     

银行间同业拆借利率的复杂性研究

本文运用复杂性理论对我国银行间同业拆借利率进行了实证研究.通过银行间同业拆借利率的关联积分关于相空间维数的数值计算发现,当相空间维数大于9以后,关联维数趋于平稳,从而确定银行间同业拆借利率的嵌入维数约为9,这时对应的关联维数约为3.64.通过对Kolmogorov熵的计算得出,我国7天银行间同业拆借利率的可预测时间尺度约为7天.本文将H.E.Hurst提出的R/S分析法应用于我国银行间同业拆借利率分析.测定了我国银行问同业拆借利率收益率的Hurst指数.运用消除趋势波动分析方法,计算了我国银行问同业拆借利率收益率的标度指数.结果表明:银行间同业拆借利率显示为状态反持续性.     

Hurricane Isaac: A Longitudinal Analysis of Storm Characteristics and Power Outage Risk

In August 2012, Hurricane Isaac, a Category 1 hurricane at landfall, caused extensive power outages in Louisiana. The storm brought high winds, storm surge, and flooding to Louisiana, and power outages were widespread and prolonged. Hourly power outage data for the state of Louisiana were collected during the storm and analyzed. This analysis included correlation of hourly power outage figures by zip code with storm conditions including wind, rainfall, and storm surge using a nonparametric ensemble data mining approach. Results were analyzed to understand how correlation of power outages with storm conditions differed geographically within the state. This analysis provided insight on how rainfall and storm surge, along with wind, contribute to power outages in hurricanes. By conducting a longitudinal study of outages at the zip code level, we were able to gain insight into the causal drivers of power outages during hurricanes. Our analysis showed that the statistical importance of storm characteristic covariates to power outages varies geographically. For Hurricane Isaac, wind speed, precipitation, and previous outages generally had high importance, whereas storm surge had lower importance, even in zip codes that experienced significant surge. The results of this analysis can inform the development of power outage forecasting models, which often focus strictly on wind‐related covariates. Our study of Hurricane Isaac indicates that inclusion of other covariates, particularly precipitation, may improve model accuracy and robustness across a range of storm conditions and geography.     

State Dependence,Serial Correlation and Heterogeneity in Intertemporal Labor Force Participation of Married Women

A dynamic search framework is developed to analyze the intertemporal labor force participation behavior of married women, using longitudinal data to allow for a rich dynamic structure. The sensitivity to alternative distributional assumptions is evaluated using linear probability and probit models. The dynamic probit models are estimated using maximum simulated likelihood (MSL) estimation, to overcome the computational difficulties inherent in maximum likelihood estimation of models with nontrivial error structures. The results find that participation decisions are characterized by significant state dependence, unobserved heterogeneity, and negative serial correlation in the error component. The hypothesis that fertility decisions are exogenous to women's participation decisions is rejected when dynamics are ignored; however, there is no evidence against this hypothesis in dynamic model specifications. Women's participation response is stronger to permanent than current nonlabor income, reflecting unobserved taste factors.     

The Relationship between Adult Students' Instructional Technology Competency and Self-Directed Learning Ability in an Online Course

The main purpose of this research was to examine the relationship between adult students' self-directed learning (SDL) ability and instructional technology (IT) competency in an online course. The study also investigated motivation and learning strategies that the students used to learn IT. The research involved surveying 198 continuing education professionals who took online courses at a large Midwest state university. The results indicate a statistically significant positive correlation between SDL ability and IT competency in students with above average SDL ability. The results also indicate that motivation is an important factor for learning technology in an online course regardless of the students' SDL ability. Additionally, the results show that students with higher level of SDL ability are likely to exhibit higher level of self-efficacy for learning and performance, and higher level of effort regulation.     

地方高校本科生学习状态自评量表的设计研究

目的:编制适用于本科生学习状态的测评量表,并检验其效度和信度。方法:在文献研究与理论研究的基础上,运用头脑风暴法、深度访谈法,结合多年的教学经验设计初始量表。采用分层随机整群抽样的方法对海南省某地方高校的本科生进行现场匿名调查。采用临界比率法、相关分析对量表条目的区分度进行分析;采用探索性因子分析对量表进行效度检验;采用内部一致性信度与分半信度对量表进行信度检验。结果:共发放652份问卷,回收有效问卷608份,有效问卷回收率为93.25%。经探索性因子分析,最终提取了5个因子,共包含28个条目,能解释总方差的56.99%。该量表的总Cronbach'sα系数为0.962,总分半信度为0.868。各维度的α系数均在0.8以上,分半信度均在0.74以上。结论:设计的本科生学习状态测评量表具有良好的效度和信度,能有效测量海南省某高校的本科生学习状态,也能为其他高校测量本科生学习状态提供参考依据。     

Financial Returns of Corporate Social Responsibility,and the Moral Freedom and Responsibility of Business Leaders

A number of theorists have proposed mechanisms suggesting that corporate social responsibility produces better financial results. Others subscribe to the theory that, realistically, less ethical means are necessary. This article contains an analysis of these perspectives drawing on observations from evolutionary game theory and nature. Based on these analyses, it is concluded that the financial returns of corporate social responsibility and irresponsibility (CSR and CSI) are equal on average. The explanation is that CSR and CSI aredriven to a state of equilibrium, because if one or the other were to offer higher profits, it would attract more players who would compete for the best opportunities until there was no difference in average profit. Existing empirical research generally shows a positive correlation between CSR as measured and corporate financial performance. It is argued that what is actually causing that finding is probably not CSR but management skill. More skillful managers, whether actually responsible or irresponsible, are able to obtain both higher profits and greater credit in imperfect measures of CSR. Next it is shown that this theory of equal returns implies greater moral freedom and therefore responsibility for business leaders. It is concluded that this insight can intensify the interest of decent business leaders in vigorously championing CSR.     

A Partial Folk Theorem for Games with Unknown Payoff Distributions

Repeated games with unknown payoff distributions are analogous to a single decision maker's “multi‐armed bandit” problem. Each state of the world corresponds to a different payoff matrix of a stage game. When monitoring is perfect, information about the state is public, and players are sufficiently patient, the following result holds: For any function that maps each state to a payoff vector that is feasible and individually rational in that state, there is a sequential equilibrium in which players experiment to learn the realized state and achieve a payoff close to the one specified for that state.     

具有多元马氏需求的多产品多阶段库存优化模型

本文研究一类新的多产品库存控制策略,即具有多元马氏需求特征的多产品多阶段的订货点订货量(Q, R, SS)策略,该策略考虑市场需求在不同产品之间具有多元马氏转移特征,并考虑缺货因素设置安全库存。论文首先建立了多产品多阶段的多元马氏需求预测模型,并通过该模型确定了各种产品需求之间的关系。同时,在该模型的理论基础上,提出了多产品多阶段的总期望成本模型及其最优(Q, R, SS)策略,进而结合算例给出模型的最优策略的数值解。     

多层网络视角下金融机构关联性的演化特征研究

基于股票收益率间Pearson相关性、Kendall秩相关性以及Tail相关性，构建了金融机构多层网络模型，其中三种相关性分别对应多层网络中Pearson层、Kendall层和Tail层。根据2010年10月至2018年3月期间我国上市金融机构的数据，实证分析了金融机构多层网络结构演化特征。实证分析结果表明：Kendall层和Tail层中的平均权重均高于Pearson层的平均权重，Pearson层和Kendall层中的平均权重变化趋势比较相似，但前者波动幅度明显大于后者；Pearson层与Kendall层的边独特性变化趋势非常相似，而Tail层的与它们有较大的差别；任意两层的度相关性均为正相关，但随时间波动均较为剧烈；Pearson层与Kendall层的相似性整体上较高，Tail层与Pearson层和Kendall层的相似性整体上均较低；多层网络中平均权重、边独特性、度相关性和相似性等结构指标变化趋势与股票市场行情相关。     

零售服务供应链动态演化中存在“质量桥”吗？

服务质量在零售服务供应链中扮演了何种角色,是近年来学术界探讨的焦点问题。本文围绕零售服务供应链动态演化过程中是否存在“质量桥”现象展开,基于马尔可夫链模型提出了零售服务供应链的服务质量预测模型,验证了服务质量稳态分布的客观存在;并以中国HJ零售企业主导的零售服务供应链为实证样本,运用系统动力学模型对7种不同经营情形下的功能服务提供商、零售服务集成商和消费者三个质量子系统之间的交互行为和系统因果关联进行了比较,探讨了零售服务供应链动态演化过程中的“质量桥”协同机制。研究发现：零售服务供应链的质量演化是一个稳态趋同的过程,在其协同演化中存在质量稳态分布,其中不同过程投入水平对质量状态的稳定水平有着显著的正向影响;且质量稳态在零售服务供应链协同演化中起到了至关重要作用,其不仅是零售服务供应链协同的约束条件,还在整体优化中扮演了“搭桥”协同的角色,在“质量桥”搭好后,即服务质量达到某种稳态分布时,整个链条的运作效率和收益水平会呈现出“爆发式”增长的态势。最后从整体设计、资源配置、过程控制与优化改进四个方面给出了对策建议。     

集成供应链系统生产决策行为混沌特性研究

供应链集成是当前供应链管理领域研究的热点和难点问题。近年来许多学者以整个供应链系统为对象,通过优化供应链上各种资源,使供应链整体效应达到最优,降低局部生产决策对整个供应链的影响。然而,由于集成供应链系统生产过程是一个复杂的非线性系统,集成供应链系统局部生产决策的复杂性导致集成建模的复杂性。现有的研究成果还难以实现集成供应链整体协调,研究方法具有很大的局限性。本文针对局部生产决策对整个集成供应链系统的影响,基于柯布—道格拉斯函数进行集成建模,并通过相空间重构确定系统的关联维数和计算最大李雅普诺夫指数来界定集成供应链系统混沌特性,为研究供应链集成的复杂性提供理论依据。     

面向评价局部环境的群评价长效机制分析

在群组评价问题中,称评价参与者(即节点集)及参与者之间的评价关系构成群组评价局部环境,即评价群体的网络结构。将评价局部环境看作是一个有限状态、不可约且非周期性马尔可夫过程,使得群组评价问题水平维度的评价局部环境基于时间维度进行拓展,证明参与者对评价关系的调整可以改善群体网络结构的稳定性;具有评价关系的参与者状态正相关;参与者不满意效用状态持续时间的增加降低了其达到满意效用状态的概率。在此基础上,讨论以被评价对象为主要研究对象设置群组评价方法,根据三种常见的评价局部环境状态,考察评价群体的群体性行为或认知趋势性特征,在此基础上讨论评价目标的可执行性。允许有关被评价对象的新信息注入群组评价系统,在长期分析评价群体的群体性评价行为的趋势特征,据此构建面向评价局部环境的群组评价方法,分析评价目标的可执行性,以期使群组评价行为具有稳定性和可预见性。     

企业现金持有量影响因素的实证研究——来自我国上市公司的经验证据

20世纪90年代末,国外企业出现持有大量现金与现金等价物的现象,为什么企业持有大量的现金与现金等价物,以及企业持有现金的后果等问题,逐步得到国外学者的关注而成为一个研究的热点,国外学者主要从权衡理论、信息不对称理论、公司治理机制,以及投资者的法律保护程度等方面展开现金持有量的研究.由于我国的经济与制度环境同国外有很大差别,我国证券市场的发展处于一个转型时期,内部人控制严重,资本市场还不完善,国外的实证结论直接移植到国内缺乏说服力.上市公司现金持有量的影响因素也逐步得到国内学者的关注,但我国的研究还处于起步阶段.本文在理论分析与文献梳理的基础上,以我国部分上市公司为样本,检验了我国上市公司的特质性因素和公司治理机制对公司现金持有量的影响.研究结果表明,公司现金持有量与财务杠杆、银行性债务、净营运资本负相关,与公司的投资机会正相关,权衡理论和优序融资理论得到了经验支持;国有股、董事会规模、股东保护程度与现金持有量负相关;经营者持股与现金持有量正相关;股权集中度、独立董事、以及领导权结构并没对公司现金持有量产生显著影响.本文从现金持有量的角度为我国上市公司治理的不完善性提供了证据,需要我们从股权结构、董事会特征等方面进一步完善公司治理机制,规范公司的现金持有行为.     

基于双变量EARJI-EGARCH的时变收益关联研究——来自东亚地区股市跳跃的分析

本文改进了双变量EARJI-EGARCH模型,并对东亚地区的中国上证指数,日本日经指数和韩国综合KS指数的跳跃和双边时变收益关联的影响进行了研究。结果表明,东亚地区股市的时变关联持续性非常高,东亚地区单个市场跳跃对时变关联影响较小,市场同时发生跳跃对市场时变关联的影响取决于跳跃的方向。当市场都发生正向的跳跃时,上证和日经指数的时变收益增量最多,当市场都发生负向跳跃时,上证和韩国KS指数的时变收益减少最多。表明在东亚地区股市同向跳跃发生时,中国和日本股市相互关联较大。且同时跳跃对时变关联的影响将远远超过了单个市场跳跃对时变关联的影响,当市场发生反向的跳跃时,也超过了单个市场跳跃的影响,但不及同向跳跃的影响,且上证和日经指数时变收益增加最多,而日经和KS指数时变收益减少的最多,表明在股市反向跳跃时同样是中国和日本股市比日本和韩国股市之间的相互关联大。     

面向开放式团队知识创新的动态标签关联网研究

知识创新是企业提高核心竞争力最重要的手段之一。当今世界经济一体化,全球创新方向正在向开放式创新转变。开放式创新环境下,跨组织、跨地域的开放式创新团队成为知识创新的主要载体。社会化标签能够使团队成员按照自己对知识的认知方式进行知识交互与协作,有利于促进开放式团队知识创新。但是由于标签标注的自由性,如何建立标签之间的关联关系以更有效地支持开放式环境中基于标签的知识管理与知识创新成为该领域的关键议题。本文研究并提出了面向开放式团队知识创新的动态标签关联网方法,并对该方法进行了应用研究,通过比较实验组和对照组的应用结果,可以发现面向开放式团队知识创新的动态标签关联网方法能够动态地展示标签之间的关联关系,从而支持开放式环境中的团队知识创新。     

Comparisons of Performance and Job Insecurity in Union and Nonunion Sites of a Manufacturing Company

Layoffs and employment changes caused by current economic conditions have significant effects on employee work behavior and emotions as well as organizational outcomes. We examined the relationships between measures of job insecurity, organizational commitment, turnover, absenteeism, and worker performance within a manufacturer in Chapter 11 bankruptcy. A positive relationship was found between job insecurity and intentions to turnover, and a small negative correlation was found between measures of job insecurity and organizational commitment. Unobtrusive observations of union and nonunion performance over 4 months showed that nonunion production workers were on-task more frequently, although on-task behavior was high for both. Productivity and quality measures of different factories favored nonunion locations. Although comparisons between sites were constrained by a quasi-experimental design, repeated behavioral and outcome measures within sites showed differential effects when the company announced a plant closing in another state. Job insecurity appeared to be an establishing operation that produced differential effects between union and nonunion sites as well as among individual employees within sites.     

基于共同持有资产的银行间接关联网络研究

金融市场是一个复杂系统,银行之间不仅有直接的拆借关系,还能够通过投资市场建立间接关联。本文分析了资产内生相关性、资产降价出售以及银行投资行为等因素对银行间接关联程度的影响,基于这些因素通过持有共同资产构建银行系统的间接关联,并以此为基础通过平面极大过滤图方法生成银行间接关联网络,论证了该网络中的系统重要性银行,并通过对该网络结构特征的分析,发现间接关联网络具有小世界和无标度等特征,这些特征与银行通过直接拆借形成的网络相似。本文对于银行间接关联网络的研究不仅能够更加清晰地了解银行之间的关系,也为银行系统性风险的监管提供了新的视角。