Effects of export product diversification on quality upgrading: an empirical study

This paper empirically examines the effects of export product diversification on overall export quality in a panel data set of 115 countries from 1970 to 2010. It uses the data sets of the overall export quality and three export diversification measures of the International Monetary Fund: the extensive margin (variation in the number of new products exported), the intensive margin (variation in export values among existing exports), and the overall (Theil) index. It finds that export quality has only been increasing with a higher variation in export values among existing exports in low- and lower-middle-income countries. It also observes that export quality has been increasing with both a higher variation in export values among existing exports and new products exported in upper-middle- and high-income countries. The results are robust to the changing measures of controls in the benchmark model, the inclusion of many other controls; i.e. various measures of globalization, country size, factor endowments, macroeconomic stance, etc., and the exclusion of outliers.     

Forecast of telephonometry of Xiqing District using chaos time series

The telecommunication industry has marched into telephonometry competition age. In order to forecast telephonometry development, an effective method by using the chaos time series is proposed. And the best estimate method is presented by contrasted with mature and advanced estimate methods as follows： the stochastic forest, stochastic gradient boosting, the support vector and artificial neuron network.     

“十五”期间我国沥青应用预测

介绍了沥青的生产和需求现状，并根据消费行为的情况对沥青的市场和价格走势进行预测，分析了国内沥青行业的存在问题。     

出口、对外直接投资与企业的异质性研究

出口和对外直接投资是一国企业进入国外市场的两种重要模式，本文通过建立一个简单的理论模型来分析企业对这两种进入模式的选择问题。本文将企业异质性引入模型分析，同时将企业的R＆D活动作为内生变量来进行研究。在理论分析的基础上，本文结合中国出口和对外直接投资发展的实际情况提出了相关政策建议。     

The Nested PIGLOG Model: An Application to U.S. Food Demand

A new demand system is introduced, the Nested PIGLOG model, nesting thirteen other demand systems including five that are also new. This new model and its nested special cases are applied to models of U.S. food demand that include food-at-home (FAH), food-away-from-home (FAFH), and alcoholic beverages. Although nested tests and out-of-sample forecasting performance favor generalizing models to a certain degree, statistically insignificant improvements to in-sample-fit and even poorer out-of-sample forecast accuracy undermine further generalizations. Based on a subset of preferred models, FAFH is found to be price and income elastic compared to FAH which is price and income inelastic.     

面向售后服务的汽车备品需求预测研究

根据面向售后服务的汽车备品需求特点的差异,本文将其分为专用配件和通用配件并分别选用不同的预测模型.对专用配件,采用基于时间序列相关的线性回归模型,并运用加权最小二乘法（WLS）估计参数.对通用配件,选用GM（1,1）模型进行需求预测.     

新兴市场国家的汇率波动与出口:一个经验分析

现有的中外文献已经对发达国家间的汇率波动与贸易之间的关系做了很多相关分析，但就汇率波动与贸易之间的关系没有取得一致性的结论。本文利用协整分析和误差修正模型，针对新兴市场国家的汇率波动与出口的关系进行了经验分析，结论是：汇率波动会在一定程度上抑制新兴市场国家的出口，但对某些新兴市场国家出口的影响并不明显，其影响程度随一国经济发展水平、经济规模和开放度的差异而有所区别。     

基于Markov链的物流园区需求灰色预测模型改进

物流因区是一项大型基础设施投资项目，在规划与设计上需要有一定的超前意识，而需求预测则是园区规划超前意识的重要依据。目前。国内外对物流园区需求预测方法的研究和实践基本上还处于发展阶段．至今尚未形成完整科学、操作性强的方法体系，现有的需求预测大体上是借鉴史通运输规划的模型．进行研究的过程中灰色模型预测有局限性。其预测结果与真实值之间存在一定误差，因而可以考虑利用Markov链提出改进方案。     

基于Web和数据仓库的房地产市场预警预报系统研究

介绍了基于Web和数据仓库的房地产市场预警预报系统的体系结构，探索设计了房地产市场预警预报系统的技术与方法，并提出了基于Web和数据仓库的房地产市场预警预报系统的完整解决方案。     

人工神经网络技术在物流需求量预测中的应用

运用人工神经网络模拟人脑的思维过程,建立了多个变量之间的非线性模型,从而为准确预测物流需求量提供了科学的依据。