On the importance of the long-term seasonal component in day-ahead electricity price forecasting with NARX neural networks

Daily and weekly seasonalities are always taken into account in day-ahead electricity price forecasting, but the long-term seasonal component has long been believed to add unnecessary complexity, and hence, most studies have ignored it. The recent introduction of the Seasonal Component AutoRegressive (SCAR) modeling framework has changed this viewpoint. However, this framework is based on linear models estimated using ordinary least squares. This paper shows that considering non-linear autoregressive (NARX) neural network-type models with the same inputs as the corresponding SCAR-type models can lead to yet better performances. While individual Seasonal Component Artificial Neural Network (SCANN) models are generally worse than the corresponding SCAR-type structures, we provide empirical evidence that committee machines of SCANN networks can outperform the latter significantly.     

The effect of permanent product discounts and order coupons on purchase incidence,purchase quantity,and spending

This paper examines the influence of a permanent discount strategy on customer purchase behavior, i.e., purchase incidence in each week, purchase quantity (in units), and total order spending (in CNY). Permanent discounts are defined as discounts continuously provided by retailers. We identify two types of permanent discounts, namely, product-specific price discounts (PD) and order coupons (OD, which can be redeemed for a total order). We collect transactional data from a Chinese online retailer and empirically examine the effects of the two types of permanent discounts and customers’ expectations of PD and OD. We find nonlinear relationships between permanent discounts and customer purchase behavior. PDs negatively influence spending when they are lower than 19% but show a positive effect beyond this threshold, hence depicting a U-shaped relationship. They also affect purchase quantity positively but at a decreasing rate. Customer expectations of PD influence purchase incidence, spending, and purchase quantity following a U-shaped patter with a positive influence appearing when PD expectations are high than 31%, 27%, and 18% respectively. On the other hand, ODs influence spending and purchase quantity positively at an increasing rate. Customer expectations of OD influence purchase incidence, spending, and purchase quantity following a U-shaped relationship where the positive influence on purchase incidence shows beyond OD expectations of 426 CNY, and the positive effect appearing on spending and purchase quantity when these expectations are higher than 34 CNY. We also find that customer expectations of discounts interact with current discount levels in their influence on spending. Combining these results and considering that order coupons negatively affect the profit margin of the total basket, we suggest that retailers should offer order coupons with relatively low value but product-specific price discounts with high discount depth.     

Price Discrimination with Private and Imperfect Information

In this paper, I investigate the competitive and welfare effects of the improvements in information accuracy in markets where firms can price discriminate after observing a private and noisy signal about a consumer's brand preference. I show that when firms believe that consumers have a brand preference for them, then they charge more to these consumers, and this price has an inverse U‐shaped relationship with the signal's accuracy. In contrast, the price charged after a disloyal signal has been observed falls as the signal's accuracy rises. While industry profit and overall welfare fall monotonically when price discrimination is based on increasingly more accurate information, the reverse happens to consumer surplus.     

Oil price shocks and American depositary receipt stock returns

In this paper we examine the impact of oil price shocks on twelve countries American Depositary Receipt (ADR) returns using monthly data from 1999.01 to 2014.12. The results show that oil price shocks have a positive and statistically significant impact on ADR return in all twelve countries. These results are robust to the inclusion of other explanatory variables such as oil price volatility and the spillover of the United States stock market. Further analysis shows that this effect is stronger in the post financial crisis time period compared to the pre-financial crisis time period.     

巷道快速掘进技术在贵州省煤与瓦斯突出煤层中的探讨与应用

巷道快速掘进技术是一项系统工程。为了实现矿井高产高效,必须以巷道快速掘进技术为前提和保障。本文以贵州省为例,探讨了巷道快速掘进技术的研究现状及影响因素。针对贵州某矿突出综合检测指标经常超限、掘进速度慢等问题,采用了高压水射流割缝与瓦斯抽放边抽边掘相结合技术。研究表明:该项技术能有效削弱煤层突出危险性,大幅度提高瓦斯抽放量且巷道掘进速度提高了2~3倍。同时根据贵州省的本土情况,提出了针对性地建议和措施,能为巷道快速掘进技术的推广与应用提供一定的指导。     

基于VAR模型的黄金价格影响因素分析

自20世纪70年代初期布雷顿森林体系崩溃之后，美国割断了美元与黄金的固定比价关系，使黄金价格步入了市场化的轨道，黄金价格的大幅波动越演越烈，这使得人们越来越重视探讨影响黄金价格的种种因素。为此，利用VAR模型对黄金价格自身、美国通货膨胀率、国际原油价格等因素与黄金价格总水平的关系进行研究。通过研究得到了各因素影响黄金价格总水平的程度，其中发现黄金价格自身的波动是导致国际黄金价格总水平上升的最主要因素，这为研究黄金价格的变动提供了重要依据。     

浅析车削用量与实际生产的联系及车削的发展趋势

阐述了车削用量与实际生产的联系,提供了部分在保证机械产品性能和质量的基础上提高生产率和缩减成本的可靠性解决办法。在仔细分析了当前机加工行业的情况下,预测了车削加工的发展方向。     

ON THE PROFITABILITY OF RESALE PRICE MAINTENANCE WHEN DEMAND IS UNCERTAIN

A previous study finds that in a market where a manufacturer faces uncertain demand and sells to consumers through competitive retailers, the manufacture wishes to support adequate retail inventories by imposing resale price maintenance (RPM). I show that if retail inventories are allocated to consumers through first‐come‐first‐served rule rather than efficient rationing rule in the game with unconstrained retail competition, imposing RPM may not be profitable. It may not encourage more retail inventories either. RPM may also lower consumer surpluses and social welfare. This study casts some doubt on the demand uncertainty theory that supports RPM.     

Migration,Unemployment, and Skill Downgrading

In this paper, we analyze the labor market impacts of immigration under flexible and rigid labor market regimes. A general equilibrium framework is developed, accounting for skill heterogeneity and labor market frictions, where unemployed medium‐skilled manufacturing workers are downgraded into low‐skilled service jobs, while low‐skilled service workers might end up unemployed. The analytical analysis shows that medium‐skill immigration decreases low‐skilled unemployment under the flexible regime, indicating a complementarity effect, while the rigid regime induces a substitution effect, leading to low‐skilled unemployment. Moreover, it leads to wage polarization. In a numerical analysis, the economic effects of different migration scenarios are quantified.     

资源税改革影响煤炭企业可持续发展

介绍了当前我国煤炭行业的现状,并以淮南矿业集团为实例,分析了淮南矿业集团面临的实际困难,及资源税改革对淮南矿业集团的影响,并给出了相应的建议。