Optimal timing of investments in advanced manufacturing systems under competition

Large initial investment in advanced manufacturing systems (AMS) makes it imperative to develop economic justification methods. Once the new system has been properly justified, a critical issue facing the firm is the optimal timing of the installation in an industry. In this paper we use a game-theoretic model by which the optimal timing of the investments in AMSs is analysed. The existence of timing equilibria is demonstrated and simple decision rules of optimal strategy are provided. Economic interpretations of the decision rules are subsequently made clear. Finally, illustrative examples are used to demonstrate the correctness and usefulness of the analysis.     

董事会里的"战争"——序贯与惩罚机制下董事会决策行为的实验分析

本文利用实验研究方法首次在独立董事人数占优的董事会中引入序贯和惩罚机制,探讨了董事会科学决策的促成因素及制度环境.实验结果发现,序贯与惩罚机制引入后,董事决策正确率较静态实验分别提高了39.09%和34.26%,但两者的作用原理不同:序贯机制着力于改善董事会的私人信息结构,通过将独立董事"知情化",从而使决策行为独立于董事类型;惩罚机制则是利用独立董事的社会偏好进行治理,使决策行为与项目类型无关.与Gillette等人的研究结果不同,好项目的通过率并不是100%,原因可能与序贯时的针锋相对策略、惩罚时的社会偏好存在有关.     

Information Independence and Common Knowledge

In Bayesian environments with private information, as described by the types of Harsanyi, how can types of agents be (statistically) disassociated from each other and how are such disassociations reflected in the agents' knowledge structure? Conditions studied are (i) subjective independence (the opponents' types are independent conditional on one's own) and (ii) type disassociation under common knowledge (the agents' types are independent, conditional on some common‐knowledge variable). Subjective independence is motivated by its implications in Bayesian games and in studies of equilibrium concepts. We find that a variable that disassociates types is more informative than any common‐knowledge variable. With three or more agents, conditions (i) and (ii) are equivalent. They also imply that any variable which is common knowledge to two agents is common knowledge to all, and imply the existence of a unique common‐knowledge variable that disassociates types, which is the one defined by Aumann.     

On the Existence of Monotone Pure‐Strategy Equilibria in Bayesian Games

We generalize Athey's (2001) and McAdams' (2003) results on the existence of monotone pure‐strategy equilibria in Bayesian games. We allow action spaces to be compact locally complete metric semilattices and type spaces to be partially ordered probability spaces. Our proof is based on contractibility rather than convexity of best‐reply sets. Several examples illustrate the scope of the result, including new applications to multi‐unit auctions with risk‐averse bidders.     

Adaptive interval estimation in one-way random effects models

Two-stage procedures are introduced to control the width and coverage (validity) of confidence intervals for the estimation of the mean, the between groups variance component and certain ratios of the variance components in one-way random effects models. The procedures use the pilot sample data to estimate an “optimal” group size and then proceed to determine the number of groups by a stopping rule. Such sampling plans give rise to unbalanced data, which are consequently analyzed by the harmonic mean method. Several asymptotic results concerning the proposed procedures are given along with simulation results to assess their performance in moderate sample size situations. The proposed procedures were found to effectively control the width and probability of coverage of the resulting confidence intervals in all cases and were also found to be robust in the presence of missing observations. From a practical point of view, the procedures are illustrated using a real data set and it is shown that the resulting unbalanced designs tend to require smaller sample sizes than is needed in a corresponding balanced design where the group size is arbitrarily pre-specified.     

Bayesian monitoring of local residual autocorrelations taking into account the run-length

This paper proposes new two-sided monitoring algorithms for detecting the presence of first order residual autocorrelations in Dynamic Normal Models. The methodology uses a Bayesian decision approach with loss function which takes into account the run-length of the process. The power and mean run-length of the proposed algorithms are analysed by Monte Carlo methods. The results obtained improve those corresponding to the monitoring algorithm for residual autocorrelations proposed in Gargallo and Salvador [2003. Monitoring residual autocorrelations in dynamic linear models. Comm. Statist. Simulation Comput. 32(4), 1079–1104.] with respect to the run-length, and also exhibit more homogeneous behaviour.     

A group sequential test for the inverse Gaussian mean

The present paper deals with the development of a group sequential test when response variable has an inverse Gaussian distribution with known scale parameter.     

游戏与口语习得

口语交际能力居于听、说、读、写“四会”之首,是最重要的语言技能,应当率先得到发展。本文以认知的观点对课堂环境下的口语习得进行了探讨,提出：只有更人性化的教学方法才是培养学生口语交际能力的最佳途径,这就是游戏的方法。     

WORK AND THE CITY IN THE e-SOCIETY A critical investigation of the sociospatially situated character of economic production in the digital content industries in the UK

The aim of this paper is to ground debates about the 'new economy' or 'e-society' in the practice of individuals and companies producing 'new media'. The uncontroversial starting point is to question the generalization in much theorizing, and the tendency to technological reductive accounts of social and economic change. The focus here is to point to the intellectual sources of much policy in this field. The authors present case study material of three very specific parts of the new media/digital content industries (film special effects, computer games and web design). The paper concludes that both technological reductive and agentic accounts have underplayed the continuing importance of the social and economic embeddedness of production, and of the situated co-constitution of technologies, people and places. The differences between industries associated with labour processes, labour markets, users and markets for goods are highlighted. These particularities begin to offer more robust accounts of location and organization.     

测字也是迷信

相信测字可以预知未来,就是迷信。但古代学人非职业性的测字,只是趣味性文字游戏。测字的手段拆字不是迷信,与抽签算卦等不完全相同,有一定的客观性、知识性。古书测字名例,都是文人编造的,不是真实的。迷信的测字,实际是以迷信的"心法"为据,用"字法"来附会。