Modelling the iron ore price index: A new perspective from a hybrid data reconstructed EEMD-GORU model

As iron ore is the fundamental steel production resource, predicting its price is strategically important for risk management at related enterprises and projects. Based on a signal decomposition technology and an artificial neural network, this paper proposes a hybrid EEMD-GORU model and a novel data reconstruction method to explore the price risk and fluctuation correlations between China’s iron ore futures and spot markets, and to forecast the price index series of China’s and international iron ore spot markets from the futures market. The analysis found that the iron ore futures market in China better reflected the price fluctuations and risk factors in the imported and international iron ore spot markets. However, the forward price in China’s iron ore futures market was unable to adequately reflect the changes in the domestic iron ore market, and was therefore unable to fully disseminate domestic iron ore market information. The proposed model was found to provide better market risk perceptions and predictions through its combinations of the different volatility information in futures and spot markets. The results are valuable references for the early-warning and management of the related enterprise project risks.     

基于模糊时间序列的预测模型——以上证指数为例

模糊理论使用语义变量本身所蕴含的特性,能减少处理问题时的不确定性所带来的困扰,被广泛的应用于各种领域的研究。首先回顾了基于模糊理论的模糊时间序列定义,对现有的模糊时间序列模型进行分析;在此基础上提出了一种新的模糊时间序列预测方法,以上证指数为对象进行了拟合。从结果看,新的基于模糊时间序列预测方法在MSN、平均误差(%)和标准误差(%)等指标上要优于现有的的预测方法。     

我国货币政策对房价作用时滞的实证分析

本文应用向量自回归模型的脉冲响应函数和预测方差分解的方法．对我国货币政策影响房价的外部时滞进行分析。利用2004年1月至2008年6月的月度数据测算出的结果是：信贷规模、狭义货币供应量和利率对房价的作用时滞分别为7个月、3个月和11个月。信贷规模和利率水平度对房价的冲击效应较小。而货币供应量对房价的冲击效应较为明显。央行在制定货币政策时应综合考虑货币工具的特点、作用时滞、经济形势和理性预期的影响。     

Profiling high-frequency equity price movements in directional changes

Market prices are traditionally sampled in fixed time intervals to form time series. Directional change (DC) is an alternative approach to record price movements. Instead of sampling at fixed intervals, DC is data driven: price changes dictate when a price is recorded. DC provides us with a complementary way to extract information from data. It allows us to observe features that may not be recognized in time series. The argument is that time series and DC-based analysis complement each other. With data sampled at irregular time intervals in DC, however, some of the time series indicators cannot be used in DC-based analysis. For example, returns must be time adjusted and volatility must be amended accordingly. A major objective of this paper is to introduce indicators for profiling markets under DC. We analyse empirical high-frequency data on major equities traded on the UK stock market, and through DC profiling extract information complementary to features observed through time series profiling.     

Time series momentum and moving average trading rules

We compare and contrast time series momentum (TSMOM) and moving average (MA) trading rules so as to better understand the sources of their profitability. These rules are closely related; however, there are important differences. TSMOM signals occur at points that coincide with a MA direction change, whereas MA buy (sell) signals only require price to move above (below) a MA. Our empirical results show MA rules frequently give earlier signals leading to meaningful return gains. Both rules perform best outside of large stock series which may explain the puzzle of their popularity with investors, yet lack of supportive evidence in academic studies.     

养老保险体制改革的动态时间一致性研究

本文构建了一个动态时间一致性模型,并利用中国数据对养老保险体系的动态时间一致性做了经验检验和动态预测。研究发现,按照帕累托效率标准对养老保险体系的参数或结构进行调整只是手段,而提高动态时间一致性才是目的。一项养老改革只有在能够同时增进社会福利和个人投资收益率时,才符合动态时间一致性原则;经验检验表明,1978～2012年间,现收现付制向基金制转轨是不符合动态时间一致性原则的;而1994年之后,将统筹比率控制在06～075之间,则有利于提高养老保险体系的动态时间一致性。预测结果表明,中国政府在2014～2037年和2038～2044年间应将统筹比率分别控制在06～09和025～06之间。     

有偏技术进步视角下中国工业产能过剩的影响因素分析

本文通过将产能利用率在生产侧与消费侧进行分解,测算了中国工业行业产能过剩指数,并考察了技术进步偏向、投资比重等因素对产能过剩的影响效果。研究发现：受生产侧与消费侧产能利用率提升的影响,中国工业总体产能过剩现象呈现下降趋势;生产技术偏向于资本,导致生产过程中偏爱资本投入,加速了投资对产能过剩的恶化程度,这在重工业行业中表现尤为明显。因此,纠正生产过程的要素使用偏好,有利于缓解当前的产能过剩现象。     

WHAT'S TO KNOW ABOUT TIME USE?

Stimulated by the availability of large sets of microeconomic data, research on the economics of time use has been a growth industry in the past 20 years. That growth has included studies that have focused on the effect of people's value of time; on the mix of nonmarket activities that they undertake; on the interactions of spouses’ choices of time use; on the valuation of nonmarket time, and on the timing of nonmarket and market activities. By laying out these research questions and indicating their importance, this essay provides a framework for a series of meta‐analyses.     

Residential Asking Rents and Time on the Market

Landlords offering a house in the rental market face a difficult strategic pricing decision. The revenue maximizing decision for the landlord involves a tradeoff between the rental rate and time on the market. Because the turnover of renters is higher than owners, and because the landlord must bear some carrying costs on a vacant house, pricing the rent too high may decrease revenue due to a higher vacancy period and pricing it too low may reduce the revenue when occupied. While there is substantial research on the relationship between listed prices and time on the market for freehold interests, this is the first study to provide empirical evidence on the relationship between asking rent, contract rent and time on the market for single family residential rental (leasehold) property interests. We present two models; a rental price model and a duration model for time-on-the market. Using data from the Dallas–Fort Worth area we find that landlords who set a lower asking rent relative to predicted rent can expect a shorter marketing period for their properties. The results also indicate that overpricing the asking rent and then lowering it at a later date leads to a longer marketing time (after the reset) and often a lower rent. These finding are reasonably robust for low-, mid-, and higher-valued rental properties.

合同环境下优化路桥项目施工总工期之方法探讨

在合同环境下,针对某一路桥工程,在一定资源的约束下,可以通过施工作业方式的选择、施工段的排序、施工段数的合理确定、项目总成本和质量控制及经理人素质的提高等方法来进一步缩短和优化路桥项目施工总工期。