The adequacy of asymptotic approximations in the near-integrated autoregressive model with dependent errors

We consider the normalized least squares estimator of the parameter in a nearly integrated first-order autoregressive model with dependent errors. In a first step we consider its asymptotic distribution as well as asymptotic expansion up to order O_p(T⁻¹). We derive a limiting moment generating function which enables us to calculate various distributional quantities by numerical integration. A simulation study is performed to assess the adequacy of the asymptotic distribution when the errors are correlated. We focus our attention on two leading cases: MA(1) errors and AR(1) errors. The asymptotic approximations are shown to be inadequate as the MA root gets close to −1 and as the AR root approaches either −1 or 1. Our theoretical analysis helps to explain and understand the simulation results of Schwert (1989) and DeJong, Nankervis, Savin, and Whiteman (1992) concerning the size and power of Phillips and Perron's (1988) unit root test. A companion paper, Nabeya and Perron (1994), presents alternative asymptotic frameworks in the cases where the usual asymptotic distribution fails to provide an adequate approximation to the finite-sample distribution.     

对中国形成世界制造中心进程的冷思考

改革开放以来，我国迅速成为制造业大国，但还远远不是制造业的世界中心。只有认清我国制造业存在的预期利润低、结构不合理、产业链的低端定位、边际效应递减、研究与开发费用不足以及教育结构对制造业的瓶颈效应等问题，并对症下药，才能将我国的制造业真正做大做强。     

全球化背景下中国文化的创新

经济全球化的进程已经深刻地波及到文化领域。面对全球化的态势我们必须深刻地反思中国文化及文化产业所面临的一系列问题。发展建设中国文化及文化产业 ,最根本的问题就是要解决文化创新的问题 ,即实施国家文化创新、文化思想学术创新和文化观念创新。     

全低变工艺开发应用中的问题与对策

讨论了全低变工艺开发过程中遇到的一些问题和对策,对中、小氮肥企业进行技术改造具有一定的参考意义。     

Asymptotic expansion of S-estimators of location and covariance

By means of a straightforward application of empirical process theory, we show that S-estimators of multivariate location and covariance are asymptotically equivalent to a sum of independent vector and matrix valued random elements respectively. This provides an alternative proof of asymptotic normality of S-estimators and clearly explains the limiting covariance structure. It also leads to a relatively simple proof of asymptotic normality of the length of the shortest α-fraction.     

煤代油工程污水处理工艺的选择

文章通过分析巴陵分公司煤代油工程的污水排放特性及技术条件,探讨了污水处理工艺的选择。     

基于六西格玛流程改进的库存管理优化

库存管理是企业用来控制实际库存问题的方法，主要帮助企业经营者确定何时补充订货、补充订货多少以及安全库存等问题。现有的库存控制研究往往只关注数学建模阶段的精确性，而对库存波动根源认识不足，导致数学模型越来越复杂、完善，但库存仍然居高不下、难以控制。本文针对该问题，提出了在库存管理中糅合六西格玛管理理念的思想，通过六西格玛方法揭示库存积压的根源，从源头着手，进行流程改进，从而达到库存优化、提高客户满意度的目的。文章通过实际案例证实了基于六西格玛理念的库存优化管理的有效性。     

国内外企业技术创新策略的博弈分析

入世后我国企业面临着国外企业日益加强的竞争压力，技术创新成为企业的重要选择。本文从技术创新成本的角度，建立了国内企业与国外企业技术创新竞争的静态博弈模型，根据模型，当国外企业以规模扩张为竞争目标时，我国企业只能选择渐进式的技术创新战略。     

Public support to innovation and imitation in a non-scale growth model

This paper studies technology policy within a version of Jones's [1995. R&D-based models of economic growth. Journal of Political Economy 103, 759–784] non-scale R&D-based growth framework that incorporates imitation of foreign techniques. In the model, imitation is the most important source of productivity growth at the beginning of the convergence process, whereas innovation dominates later on. In addition, the transitional dynamics of the model can account for well-known empirical regularities regarding the relationship between the level of economic development and public support to technology innovation and imitation. The paper shows as well that, even though policy in Jones-type non-scale models has no long-run growth effects, level effects can be substantial.     

Reconfiguring the innovation policy portfolios for Taiwan's SIP Mall industry

Since the year 2000, silicon intellectual property (SIP), which can minimize the gap in ‘design productivity’ that exists with systems-on-chip (SOC), has become one of the most important factors in the development of integrated circuit (IC) products in the SOC era. Although SIP is very important for IC industry development, complicated business, technical as well as legal issues inside SIP transactions have hindered successful transactions and the integration of SIPs into SOCs. Thus, web-based SIP e-Commerce mechanisms, called SIP Malls, have emerged, aiming to resolve complex SIP issues. To maintain its leading position and competitiveness in the World's IC industry, as well as the value added by SOC products in Taiwanese IC firms, the Taiwanese government has developed SIP Malls, using innovation policy tools. However, the Taiwanese SIP Mall industry remains immature. No existing Taiwanese SIP Malls generate a profit or account for a significant share of worldwide SIP transactions. This research will develop an analytical framework for defining an innovation policy portfolio that aims to develop Taiwan's SIP Mall industry, so that it will enhance the value added of SIP Malls and, thus, the nation's competitiveness in the SIP and IC industries, something which already has become one of the Taiwanese government's major concerns. The industry innovation requirements (IIRs) are summarized using the Delphi method. Meanwhile, the major IIRs identified by Decision Making Trial and Evaluation Laboratory (DEMATEL) are introduced. After the IIRs are derived, the relationships between the IIRs and innovation policy tools are derived by Grey relational analysis (GRA). Then, the innovation policy tools are clustered, based upon the Grey grades derived by GRA. Finally, reconfigured innovation policy portfolios are presented for the Taiwanese government's policy definition. The results demonstrate that developing an innovative policy portfolio that includes scientific, technical, educational, public enterprise, information, legal and regulatory, financial, and taxation policy tools will be the most necessary step towards developing Taiwan's SIP Mall industry.