Two state capital accumulation with heterogenous products: Disruptive vs. non-disruptive goods

The paper considers the problem of a firm that, while producing a standard product, has the option to introduce an innovative product. The innovative product competes with the standard product and will therefore reduce revenues of the standard product. A distinction is made between innovative products that do or do not become even more relatively appealing as their market share grows (e.g., because of network externalities). It is shown that in the former case, which we call a “disruptive” good, history dependent long run equilibria can occur, which are in line with recent real life economic examples.     

EKC-type transitions and environmental policy under pollutant uncertainty and cost irreversibility

Previous studies have suggested that some pollutant levels first increases due to the economic growth and then start decreasing, the pattern being called the “environmental Kuznets curve” (EKC). We examine EKC-type transitions of pollutant levels not with respect to economic growth but more generally in time. Assuming that each policy maker optimally executes the two switching options of regulation and unregulation for pollution, the switching dynamics of environmental policy can be described by an alternating renewal process. It is shown that the double Laplace transform of transition density of a pollutant level can be obtained by a novel application of renewal theory. The expected level of overall pollutants is then calculated numerically and found to exhibit either a Λ‐shaped or an N-shaped pattern in time. Our results present a simple explanation for the EKC-type transitions of pollutant levels within a real options framework.     

流通业增加值占GDP比重变化规律研究——基于我国省级面板数据的实证分析及理论解释

在经济发展过程中,流通业增加值占GDP比重的变化规律很少受到关注。2001年,Anderson和Betancourt指出流通业增加值占GDP的比重和经济增长的长期关系呈倒U型,并运用跨国面板数据进行了实证分析,但没有给出理论解释。选取我国各省1993-2008年的数据,建立静态面板数据模型,对流通业比重和经济发展水平的关系进行了实证分析,结果表明我国流通业比重存在先升后降的倒U型规律。将流通服务看作流通部门的产出,构建流通部门的CES生产函数,对这一规律进行了理论解释。研究启示是:流通业比重变化存在客观规律,不能因流通业属于传统服务业而忽视甚至试图降低其在GDP中的比重,需要遵循这一规律,为服务业结构优化和升级提供相应的政策支持。     

中国物质消耗—收入关系的理论与实际分析

本文先提出了一个物质消耗与收入关系的理论模型。然后,对我国及我国经济较为发达的广东省和上海市的物质消耗与国内生产总值进行实证分析。本文的结论是,目前即使是经济发达的地区,物资消耗与GDP的关系没有表现出强去物质化,而是呈正相关,但相关曲线的斜率逐渐递减。所以,我国未来的一段时间里,经济发展需要更多的物质投入,但对物质投入的依赖性将下降。     

Is there a Laffer curve between aggregate output and public sector employment?

This paper develops a model of the relationship between public sector employment, total output and aggregate real demand in market prices, where public employment has a positive productivity effect on private output. Public employment crowds out private employment and output because its increase induces higher wages and taxes. The valuation of government output is also taken into account. While public employment affects total output and aggregate real demand in an a priori ambiguous way, numerical simulations suggest that the relationship may be nonlinear; positive, when public sector is “small” and negative, when it is “large”. Using the annual data from 22 OECD countries over the period 1960–1996 and estimating and testing for threshold models and more commonly used specifications with multiplicative interaction terms give support to this nonlinearity hypothesis between public employment and private sector output. First version received: October 1996/Final version received: April 2000     

Dynamic technological learning trends in Turkish manufacturing industries

Efficient development of industries requires a broad range of technological capabilities which can be acquired only by a long process of learning. Continuous measuring and monitoring of the ever-changing technological learning would be useful for building technological capability and managing technological policies. Nevertheless, research on how to measure the technological learning over time at macro levels remains largely untouched. In this paper, by adding the experience curve into the multifactor productivity part of Neoclassical production function, we will develop a model which will allow one to estimate the technological learning levels over long periods. This model would allow a user to both estimate the past learning experiences and forecast its future path on a time varying basis. The model has been used and tested in the estimation of the annual technological learning values for 28 Turkish manufacturing industries from 1981 to 2000.     

等螺旋角锥度棒铣刀制造方法实践

等螺旋角锥度棒铣刀具有切削平稳、切削效率及耐用度高等特点。由于锥度棒铣刀的刀坯是一个圆锥体,当它有一个不变的螺旋角ω时,它的导程是不等的,这就给制造带来了困难。而找出其几个主要参数之间的函数关系,利用数控机床加工是一种便捷的方法。文本对其函数关系进行了推导,对加工其螺旋槽数控程序的编制及加工过程中需注意的几个问题作了介绍。     

单螺杆泵的合理选择研究

为合理选择单螺杆泵,将螺杆泵抽油井作为一个大的生产系统,把油层、套管、油管、井下螺杆泵机组和井口作为5个子系统,利用系统节点分析法,确定出泵的工作载荷,并根据油井的实际工作参数,对泵特性曲线进行换算。由油井工作参数和单螺杆泵输油特性曲线对比可知,单螺杆泵的特性曲线和油井工作参数配合最好的情况是:油井的工作点应位于泵特性曲线Q0-H0的下面,而且在高效区的开始处。实践证明,采用这种方法选泵,既能保证油井的产量,又能明显地提高单螺杆泵整套装置的效率,还能延长泵的使用寿命。     

《西方经济学》宏观部分若干概念错误与纠正——与厉以宁、朱善利、章铮等商榷

文章阐述了宏观经济学中几个重要的基本概念,指出了厉以宁先生主编的《西方经济学》一书中的几处基本概念表述的错误,并进一步作了纠正,欲与作者商榷。