Short- and long-run rolling causality techniques and optimal window-wise lag selection: an application to the export-led growth hypothesis

The literature devoted to the export-led growth (ELG) hypothesis, which is of utmost importance for policymaking in emerging countries, provides mixed evidence for the validity of the hypothesis. Recent contributions focus on the time-dependence of the relationship between export and output growth using rolling causality techniques based on vector autoregressive models. These models focus on a short-term view which captures single policy-induced developments. However, long-term structural changes cannot be covered by examinations related to the short-term. This paper hence examines the time-varying validity of the ELG hypothesis for India for the period 1960–2011 using rolling causality techniques for both the short-run and long-run horizon. For the first time, window-wise optimal lag-selection procedures are applied in connection with these techniques. We find that exports long-run caused output growth from 1997 until 2009 which can be seen as a consequence of political reforms of the 1990s that boosted economic growth by generating foreign direct investment opportunities and higher exports. For the short-run, export significantly caused output in the period 1998–2003 which followed a concentration of liberalization measures in 1997. Causality in the reversed direction, from output to exports, only seems to be relevant in the short-run.     

基于PDCA的电信运营企业投资战略管理体系

电信运营企业的投资战略管理工作面临着诸多挑战,在PDCA循环（戴明环）理论的基础上,提出了基于公司战略的电信运营企业PDCA投资管理体系及其实施架构,着重分析了投资管理中“后评估”的意义,重点关注企业投资战略管理的全过程及管理结果的持续改进,从而获得提升管理水平的新出路。     

球面动压滑动轴承的承载量分析

本文主要对球面动压滑动轴承的润滑机理进行分析,由球坐标系统建立二维流动的雷诺方程及考虑径向和轴向两项偏心半后建立的油膜厚度方程,联立求解上述两方程,最后获得油膜的压力分布曲线,并对其承载量的特点进行了分析计算。     

可变参数动态灰色预测模型的建立与实证研究

在固定参数动态灰色预测模型基础之上进行改进,提出了可变参数动态灰色预测模型.固定参数动态灰色预测模型的参数值为0.5,可变参数动态灰色预测模型的参数值由预测对象的影响因素来决定.根据对我国集成电路产业的应用研究,说明了可变参数动态预测模型具有更好的预测精度.同时,针对可变参数动态灰色预测模型的计算量很大的特点,应用Java编制了应用软件,可以方便快捷地进行运算,有利于该模型的应用推广.     

控轧控冷工艺对60Si_2Mn弹簧钢组织性能的影响

在实验室条件下研究了控轧控冷工艺对60 Si_2Mn弹簧钢组织性能的影响。研究表明:60Si_2Mn钢采用奥氏体再结晶区控轧,轧后以6～10℃/s冷却速度控制冷却,可获得球团细小且均匀的珠光体加少量铁素体组织,热轧钢材的强韧性显著提高,同时减少了脱碳。     

管理层权力与企业价值：基于产品市场竞争的视角

以2005－2011年上海证券交易所A股市场为研究对象,将个人和机构投资者情绪的影响进行对比研究以明确两种情绪在市场中扮演的角色。以往的相关研究大多关注两者的相互影响或其中一种对市场的影响,本文将两者同时考虑,并利用滚动回归方法从量化股票收益对投资者情绪变化的敏感度这一新视角深入到个股层面。研究表明:机构投资者情绪可以帮助预测个人投资者情绪,反之不成立;另外,机构投资者在市场上表现得更为理性,他们的情绪能够预测后市,而个人投资者情绪不具有预测性;进一步研究后发现,投资者关注度越高的股票,其收益对投资者情绪变化的敏感度越高,这种现象无论是在对个人还是对机构投资者情绪变化的敏感度上均表现出一致性。     

论语言发展的滚动模式与语言规范的基本原则

语言发展的主要内容是语言内部结构某些要素的变化、补充、消失。本文阐述语言发展的“滚动模式” :将语言发展、变化的过程视为滚动前进的球 ,即语言球 ,进而阐述语言球的三个组成部分—基本成分、新生成分、历史成分 ,在此基础上阐述了以语言发展“滚动模式”为理论依据的语言规范三项基本原则     

基于邻域相关性小波去噪的滚动轴承包络解调及故障分类

将邻域相关性的冗余第二代小波应用于滚动轴承信号降噪,用Hilhert包络解调法提取的故障特征频率,比较不 同转速和载荷下的提取效果,提出包络幅值峭度指标,并将其输入BP神经网络进行故障诊断。结果表明：基于邻域相关 性的冗余第二代小波降噪方法能很好的抑制噪声,保留原信号的信息;降噪后的故障信号经过Hilbert包络解调能找到 特征频率及其倍频,其效果优于原始信号的包络解调分析。工况会影响分析效果,且速度对提取效果的影响大于载荷。 包络幅值峭度指标能很好区分不同工况的故障信号,结合BP人工神经网络诊断正确率为100%。     

A revisitation of the export-led growth hypothesis in Malaysia using the leveraged bootstrap simulation and rolling causality techniques

According to the neoclassical growth theory, export expansion could stimulate economic growth because it promotes specialisation and raises factor productivity. Thus, many developing countries depend heavily on export-orientated businesses to accelerate economic growth. Nevertheless, the causality evidences on the export-led growth hypothesis remain elusive and controversial. Two primary empirical questions emerged in the international trade and development literatures are: (a) Does the export-led growth hypothesis still valid? (b) Why causality evidences are inconsistent among studies? In light of these, the present study attempts to contribute to the export-led growth literature by using the Malaysian data set. This study covers the monthly data set from January 1975 to August 2010. To achieve the objectives of this study, we employ the leveraged bootstrap simulation causality test and also the rolling regression-based causality tests. The leveraged bootstrap simulation causality results suggest that exports and output growth are bilateral causality in nature. However, the rolling causality results demonstrate that the causality inferences for export-led growth hypothesis are unstable over time. For this reason, policy initiative to promote exports may not always stimulate economic growth and development in Malaysia. Therefore, balancing policy is urged to ensure that the economic growth in Malaysia can be materialised.     

定频滑模控制Buck变换器设计

针对滞环调制的滑模控制开关变换器的开关频率随输入电压或负载变化而变化的问题,介绍了一种可以将切换函数直接转换成固定频率的开关控制信号的定频调制方法。详细分析了该调制方法的工作原理,给出了一种模数混合电路实现方案,研究了其在滑模控制Buck变换器中的应用。通过计算机仿真研究了该定频调制技术的可行性和有效性,仿真结果表明该调制技术保持了滞环调制具有快速瞬态调节能力,同时具有恒定开关频率、利于滑模控制器的集成和数字实现的优点。