Use of minimum risk approach in the estimation of regression models with missing observations

This article considers a linear regression model with some missing observations on the response variable and presents two estimators of regression coefficients employing the approach of minimum risk estimation. Small disturbance asymptotic properties of these estimators along with the traditional unbiased estimator are analyzed and conditions, that are easy to check in practice, for the superiority of one estimator over the other are derived. Received May 2001     

西气东输工程用感应加热弯管技术条件探讨

在对国外X70管线弯管技术条件进行调查分析与研究的基础上，对其中的几个关键技术问题包括母管成分，弯管的制造工艺和技术路线，强度与韧性要求，屈强比，Cu污染问题等进行了讨论。一些观点在西气东输感应加弯管技术条件中得到应用。     

Sunspot fluctuations in dynamics with predetermined variables

Summary. In this paper, I study the existence of Sunspot Equilibria in a general framework whose dynamics allow for the presence of predetermined variables in the system. The main motivation for this research comes from the fact that previous studies did not allow for such predetermined variables which, nevertheless, appear quite naturally in economic models. I show, for a non-negligible subset of dynamics with predetermined variables verifying usual assumptions, the existence of Stationary Sunspot Equilibria fluctuating between an arbitrary finite number of states arbitrarily close to a steady state. Received: March 1, 1995; revised version September 18, 1996     

How are China''s state-owned enterprises doing in the 1990s? Evidence from three interior provinces

Since its inception in the early 1980s, the success of China's enterprise reforms remains hotly debated. This paper introduces a new element into the analysis of state-owned enterprise performance by drawing on the recent increase in inter-regional income disparities. It is argued that as a result of less favourable structural conditions and stronger fiscal dependence on the central government, reform implementation in the interior provinces has lagged behind the progress made along the coast. This hypothesis is investigated using enterprise survey data from three interior provinces which is compared to a similar survey carried out earlier in four coastal cities. The evidence generally supports the view of larger administrative restrictions in the interior and relatively poor economic performance.     

Futures and forward price differential and the effect of marking‐to‐market: Australian evidence

The objective of this paper is to examine the effects of marking‐to‐market of futures contracts on the price differential between futures and forward contracts based on the predictions of the Cox, Ingersoll and Ross (1981) (CIR) model. Cox et al ., (1981) derive a series of propositions with respect to the relationship between futures and forward prices and a set of testable implications. These are tested empirically in this paper using Australian data from November 1991 to June 1997. The results provide evidence of the presence of significant futures and forward price differences, where the futures price is consistently below the forward price. Only partial support is found for the Cox et al ., (1981) propositions, implying that the effect of marking‐to‐market is not able to fully account for the price differential. Therefore, it is not possible to rule out the influence of other institutional factors on the futures‐forward price difference.     

Strategic alliances and internationalisation in the aircraft manufacturing industry

Based on an indicator measuring the technological level of aircraft, this paper shows that in the aircraft industry, firms are obliged to deal not only with high technological barriers, but growing financial and market barriers, too. In order to reduce these, a complex network of relationships has developed over time. This network involves both main firms belonging to the world oligopoly and firms capable of offering specialised technology and/or a potential broadening of the market. The result is a worldwide production organisation. This paper highlights the fact that the aircraft industry is undergoing a global reorganisation featuring an integration process where six groups (two in Europe and four in the United States) have come to the fore. In the future, it will be possible to imagine new forms of co-operation between the emerging European and American groups.     

When and how should infant industries be protected?

This paper develops and analyzes a welfare maximizing model of infant industry protection. The domestic infant industry is competitive and experiences dynamic learning effects that are external to firms. The competitive foreign industry is mature and produces a good that is an imperfect substitute for the domestic good. A government planner can protect the infant industry using domestic production subsidies, tariffs, or quotas in order to maximize domestic welfare over time. As protection is not always optimal (although the domestic industry experiences a learning externality), the paper shows how the decision to protect the industry should depend on the industry's learning potential, the shape of the learning curve, and the degree of substitutability between domestic and foreign goods.Assuming some reasonable restrictions on the flexibility over time of the policy instruments, the paper subsequently compares the effectiveness of the different instruments. Given such restrictions, the paper shows that quotas induce higher welfare levels than tariffs. In some cases, the dominance of the quota is so pronounced that it compensates for any amount of government revenue loss related to the administration of the quota (including the case of a voluntary export restraint, where no revenue is collected). In similar cases, the quota may even be preferred to a domestic production subsidy.     

Heterogeneity and Share Contracting in Medical Group Practices

This paper offers an empirical analysis of the relationship between income sharing rules and physician heterogeneity in medical group practices.The economies to group formation associated with risk–sharing, mutual monitoring,and internal referral are served by sharing at least a portion of group income equally. Sharing group income equally is problematic, however, when group members differ in their contribution to group income. Member contributions to group income may differ because of differences in ability, effort, or the price of services across specialty fields. The analysis below is addressed to the question of how income sharing rules in physician groups are affected by variation in member contributions. The analysis finds evidence that heterogeneity in member contributions to group income limits the use of equal income sharing rules in multispecialty groups relative to single specialty groups, and large groups relative to small groups. Nevertheless, 65% of all groups in the survey share at least a pn of group income equally, which broadly suggests that the joint surplus enhancement from risk sharing, mutual monitoring, and internal referral are sufficient to overcome the incentive problems of such rules     

基于M／N检测的高距离分辨率信号的速度补偿

本文介绍了进步频率高距离分辨率信号，分析了运动速度对该高距离分辨率信号的影响，提出了基于多散射中心联合检测（Ｍ／Ｎ检测）的速度环路补偿方案。该方案使用多距离单元的联合检测完成高距离分辨率信号的最佳速率补偿，同时进一步降低目标的虚警概率，提高了目标的发现概率。     

北京市房地产业发展的现状、问题与对策

本文在对北京市房地产业现状进行总体分析的基础上,针对其存在的主要问题提出了在新一轮宏观调控下的发展对策.