Sample size determination for testing equality in frequency data under an incomplete block crossover design

When there are more than two treatments under comparison, we may consider the use of the incomplete block crossover design (IBCD) to save the number of patients needed for a parallel groups design and reduce the duration of a crossover trial. We develop an asymptotic procedure for simultaneously testing equality of two treatments versus a control treatment (or placebo) in frequency data under the IBCD with two periods. We derive a sample size calculation procedure for the desired power of detecting the given treatment effects at a nominal-level and suggest a simple ad hoc adjustment procedure to improve the accuracy of the sample size determination when the resulting minimum required number of patients is not large. We employ Monte Carlo simulation to evaluate the finite-sample performance of the proposed test, the accuracy of the sample size calculation procedure, and that with the simple ad hoc adjustment suggested here. We use the data taken as a part of a crossover trial comparing the number of exacerbations between using salbutamol or salmeterol and a placebo in asthma patients to illustrate the sample size calculation procedure.     

需求不确定条件下的制造商订单分配模型

制造商的订单分配作为供应链模型微观层面的重要组成部分,对提升整个供应链效率有很大影响,但需求层面的不确定因素加大了订单分配的难度。以按比例分配为原则,讨论在需求不确定条件下完全信息与不完全信息两类多供应商-单制造商的订单分配模型。重点研究完全信息条件下各方的分散决策和集中决策,由于后者能避免各参与方对其他决策方的边际影响,所以能够实现供应链总利润的最大化;其次又将不完全信息引入模型,讨论制造商如何通过折算因子结合已有信息对供应商的私人信息进行估计,进而做出决策。最后以需求服从正态分布为例对两类模型进行验证。     

Parametric Inference in Stationary Time Series Models with Dependent Errors

This article is concerned with inference for the parameter vector in stationary time series models based on the frequency domain maximum likelihood estimator. The traditional method consistently estimates the asymptotic covariance matrix of the parameter estimator and usually assumes the independence of the innovation process. For dependent innovations, the asymptotic covariance matrix of the estimator depends on the fourth‐order cumulants of the unobserved innovation process, a consistent estimation of which is a difficult task. In this article, we propose a novel self‐normalization‐based approach to constructing a confidence region for the parameter vector in such models. The proposed procedure involves no smoothing parameter, and is widely applicable to a large class of long/short memory time series models with weakly dependent innovations. In simulation studies, we demonstrate favourable finite sample performance of our method in comparison with the traditional method and a residual block bootstrap approach.     

Community Based Rural Health Care in India

SUMMARY

India is a large country, geographically as well as popula-tionwise. The majority of its population lives in rural areas, i.e., villages. Again, most of the villages are in remote areas. The State has been making sincere efforts to make the basic social services accessible to all in the rural area. Health being one of the vital services, it has been a challenging task before the State to extend it to the remote rural areas, many of which are not yet connected by motorable roads. As a result of various experiments carried out over the last five decades, the State has developed a fairly well-designed primary health care service, and it is in operation in rural areas. However, there appears to be a striking gap between the delivery of health services in rural areas and utilization of the services by the people. Attempts have been made in this article to apprise the readers of the health service system in India, and it discusses the issue of health service delivery at the village level. The discussion is based on a small study carried out in a rural area in the State of West Bengal (India) where students of social work of the University to which the author belongs are placed for field work. Following the inputs received through supervision of the students' work, the study was initiated and conducted.

This article based on the study seeks to focus on peoples' perception of the health services as provided by the State in rural areas, which in turn gets reflected in the extent to which they utilize the services. Social workers being an integral part of the health set up, their role bears special significance. Discussion, therefore, centres on scope for social work intervention at the community level as well as in institutional level of the health service delivery system to make the services meaningful and effective in rural areas. In fact, it has to take the leadership role in reforming the service delivery system when required.     

印尼J区块层序地层与沉积相特征研究

利用层序地层学理论,对印尼J区块古近系—新近系的层序地层和沉积相特征进行了研究。古近系—新近系可以分为7个中期基准面旋回（SQ1SQ7）和17个短期基准面旋回。SQ1SQ7沉积时期,沉积环境从陆相河流环境逐渐过渡到三角洲环境和浅海环境,再到河流环境,为一完整的水进-水退旋回。中下部层序上升旋回占主体,属海进式沉积组合序列;上部层序下降旋回占主体,多为海退式沉积组合序列。结合层序特征,指出区块西部凸起带SQ5旋回的浊积砂体、基底风化壳、碳酸盐岩台地和东部斜坡带的下切谷为区块的有利勘探区带。研究结果对该盆地的石油勘探具有指导意义。     

Competition in Financial Innovation

This paper examines the incentives offered by frictionless markets to innovate asset‐backed securities by owners who maximize the assets' values. Assuming identical preferences across investors with heterogeneous risk‐sharing needs, we characterize economies in which competition provides insufficient incentives to innovate so that, in equilibrium, financial markets are incomplete in all (pure strategy) equilibria, even when innovation is essentially costless. Thus, value maximization does not generally result in complete markets.     

Experimental Games on Networks: Underpinnings of Behavior and Equilibrium Selection

In this paper, we describe a series of laboratory experiments that implement specific examples of a general network structure. Specifically, actions are either strategic substitutes or strategic complements, and participants have either complete or incomplete information about the structure of a random network. Since economic environments typically have a considerable degree of complementarity or substitutability, this framework applies to a wide variety of settings. We examine behavior and equilibrium selection. The degree of equilibrium play is striking, in particular with incomplete information. Behavior closely resembles the theoretical equilibrium whenever this is unique; when there are multiple equilibria, general features of networks, such as connectivity, clustering, and the degree of the players, help to predict informed behavior in the lab. People appear to be strongly attracted to maximizing aggregate payoffs (social efficiency), but there are forces that moderate this attraction: (1) people seem content with (in the aggregate) capturing only the lion's share of the efficient profits in exchange for reduced exposure to loss, and (2) uncertainty about the network structure makes it considerably more difficult to coordinate on a demanding, but efficient, equilibrium that is typically implemented with complete information.     

上市公司信息披露的一个经济博弈分析

运用博弈论的基本原理,建立监管者、管理者和投资者的上市公司信息披露三方博弈模型,以管理者的决策策略为切入点,从不完全信息静态博弈、动态博弈两个角度,对上市公司信息披露问题进行了研究。通过分析揭示了三方博弈模型的博弈均衡结果,说明应提高上市公司的信息披露条件,指出单纯加大事前监管和事后检查都不能够提高上市公司信息披露质量,监管者要采取“两手都要抓,两手都要硬”的策略;同时,在给定监管环境下,加大惩罚力度,提高资本市场的有效性都有助于提高上市公司信息披露质量。     

从集合论看商品的市场赋价——调研宣传以及生产的逻辑

经济不断为数学“立法”的同时,数学也不断为经济提供非直觉现象的研究工具。在数学和经济不断渗透的背景下,跳过传统商品赋价理论,从集合角度重新审视了商品的赋价问题,得出商品的价格包括在消费者正确识别的商品功能集合中被赋的价格,在识别错位的功能集合中被赋的价格以及在扩充的功能集合中被消费者赋的价格三部分;同时顺便考察了厂商的宣传调研以及生产的逻辑,给出为什么商品的生产价格并不总是和市场价格相切合的解释。     

不完全契约、非对称信息与合作社经营者激励——农民专业合作社“委托—代理”理论模型的构建及其应用

我国农民专业合作社内部的委托—代理关系有其自身的特点,通过对符合我国农民专业合作社运行实践的委托—代理理论模型的构建及理论分析可知,合作社代理人努力行为的激励与其自身经营农产品占合作社经营农产品总量的比重、对互惠关注的敏感性程度和占有合作社盈余分配的比例等因素存在正相关关系。合作社内部产生委托—代理问题的根源在于合作社内部的不完全契约和非对称信息,为避免合作社经营者可能采取的隐藏信息和隐藏行动的机会主义行为,建议从信号传递和信号甄别的角度对合作社内部的相关契约加以改进。