Predictive regressions under asymmetric loss: Factor augmentation and model selection

This paper discusses the specifics of forecasting using factor-augmented predictive regressions under general loss functions. In line with the literature, we employ principal component analysis to extract factors from the set of predictors. In addition, we also extract information on the volatility of the series to be predicted, since the volatility is forecast-relevant under non-quadratic loss functions. We ensure asymptotic unbiasedness of the forecasts under the relevant loss by estimating the predictive regression through the minimization of the in-sample average loss. Finally, we select the most promising predictors for the series to be forecast by employing an information criterion that is tailored to the relevant loss. Using a large monthly data set for the US economy, we assess the proposed adjustments in a pseudo out-of-sample forecasting exercise for various variables. As expected, the use of estimation under the relevant loss is found to be effective. Using an additional volatility proxy as the predictor and conducting model selection that is tailored to the relevant loss function enhances the forecast performance significantly.     

Automated topic modeling of tourist reviews: Does the Anna Karenina principle apply?

Automated content analysis of online travel reviews allows identification of topics of travelers' satisfaction, yet its domain is not well researched. We suggest that the Anna Karenina principle positing a greater variability of the factors leading to business failure as opposed to those leading to success can be applied to the domain of visitors’ reviews of historic and cultural attractions. The larger variability of issues in reviews of dissatisfied visitors is likely to result in limitations for automated topic modeling. We confirm our proposition using TripAdvisor reviews of the Terracotta Army museum in China, and validate the outcome with two additional sites. The study strongly suggests that application of unsupervised topic mining algorithms to negative reviews may be problematic and the results should be treated with caution. The main themes of dissatisfaction of visitors to all three sites are reported and practical implications for management of the attractions are discussed.     

Expenditure on different categories of meat in Greece: the influence of changing tastes

This paper employs a latent variable approach to isolate the effects of changing tastes on the share of total meat expenditure on different categories of meat products in Greece during the period 1965–1995. We find that changes in the relative expenditure on different categories of meat cannot be explained by changes in the relative prices of the different meat products and increased expenditure alone. For pork products in particular, the increase in the share of expenditure has been greater than would be expected as a result of the relative fall in their price. The increase can therefore be associated with changes in taste. This finding is of general interest to those conducting empirical research into consumer behaviour both in economies where there have been significant changes in patterns of food consumption, and where, as in the case of many less industrialised economies, rapid structural changes in food consumption patterns are still to come. It is also of importance to policy makers in assessing die effectiveness of advertising or promotional campaigns in influencing longer term changes in consumer preferences for different products.     

东部地区农业结构变动与政策变量之间的相关性研究

本文通过农民收入变量、农民受教育程度、农村人均固定资产投资额、政府用于农村人均文教娱乐用品及服务支出和政府用于农村财政支出等政策变量与东部地区农业结构变动的相关性分析,再根据未来若干年我国及东部地区农业政策变化趋势,从而预测未来我国东部地区农业结构的变化趋势。     

基于遗传算法的钢筋混凝土梁离散优化设计

首先给出钢筋混凝土矩形截面简支梁的离散优化模型，进而给出了简化的数学模型，设计了相应的适应度函数，用改进遗传算法来寻求最优设计方案，取得了较好的效果。     

中国城市住宅市场的结构差异性分析

市场价商品房、经济适用住房和廉租房构成了目前中国城市住宅市场的供应体系.依据中国30个主要城市的房地产开发统计数据,选择吸纳率作为评价住宅市场供需均衡状态的指标,利用固定影响变截距模型,重点研究了商品房和经济适用住房供给结构的城市差异性.研究发现,在城市住宅市场中,经济适用住房市场和商品房市场具有很强的相关性.作为具有政府资助性质的经济适用住房建设,存在典型的地域性特征,其政策的设定和实施会对整个住宅市场产生影响,地方政府应在利用比较全面的住宅市场指标体系进行综合分析基础上,制定适合本地的经济适用住房政策.     

货币升值对不同产业就业的影响——对亚洲八国汇率与就业关系的经验分析

为了研究人民币升值可能对中国各产业就业影响,且避免单独研究中国数据所产生的局限性,本文选取八个亚洲主要国家和地区的数据,利用面板数据模型进行实证分析。实证结果显示汇率升值将对制造业的就业产生负效应,而对第三产业的效应为正,按照该结果,人民币升值将会给中国本已严峻的就业形势带来更大的压力。根据中国各产业就业形势的当前状况及发展趋势,解决中国就业问题的根本出路在于大力发展第三产业。     

基于应变数线性变换的约束广义G-M估计

考虑线性变换对约束线性模型回归系数的影响问题，证明了观测数据的线性变换对于约束模型的影响可以通过一个可用两步约束最小二乘法解决的约束回归问题进行了分析，得到了回归系数的约束可估函数的约束最佳线尾无偏估计不受变换影响的充要条件。     

既有结构可靠度的模糊算法

基于结构抗力和荷载效应的不确定性，提出了一种既有结构工程可靠度的模糊算法。该方法利用模糊算法可以反映客观事物因素的层次性，又便于比较和考虑各层次中诸因素作用的大小以决定可靠度。算例结果表明该方法简单实用，其模型可以很好地拟合真实的极限状态函数，是解决既有结构体系可靠度问题的有效方法。     

关于循环经济模式的可行性分析

循环经济将环境和资源投入看做是社会经济发展的内生因素,是实现人类社会可持续发展的基础。本文从循环经济的内涵出发,通过深入分析得出各国分别实现循环经济并不等于全球循环经济或可持续发展目标的实现。