最低工资对中国就业和工资水平的影响

本文以1998—2007年全国各市(地区、自治州、盟)最低工资标准随时间变化的外生差异来识别最低工资上涨与企业平均工资、企业雇佣人数的关系。利用1998—2007年规模以上制造业企业报表数据进行的分析显示,最低工资每上涨10%,制造业企业平均工资将整体上涨0.4%—0.5%。借助2006—2007年福建省最低工资上涨的"准自然实验"本文也证实了该结论。对于不同行业、不同人均资本水平的企业,最低工资上涨的影响也存在异质性。最低工资将更多地增加劳动密集型或人均资本较低企业的平均工资。研究还发现,最低工资每增加10%,制造业企业雇佣人数将显著减少0.6%左右。政府在制定最低工资时应权衡其在收入分配上的积极效果以及其对就业的负面影响。     

An analytical approximation for pricing VWAP options

This paper proposes a unified approximation method for various options whose pay-offs depend on the volume weighted average price (VWAP). Despite their popularity in practice, very few pricing models have been developed in the literature. Also, in previous works, the underlying asset process has been restricted to a geometric Brownian motion. In contrast, our method is applicable to the general class of continuous Markov processes such as local volatility models. Moreover, our method can be used for any type of VWAP options with fixed-strike, floating-strike, continuously sampled, discretely sampled, forward-start and in-progress transactions.     

面向产品创新要求的协同创新客户选择

现有协同创新客户选择方法主要从客户自身特点出发,未充分考虑产品创新要求的影响。鉴于此,提出了综合考虑产品创新要求和客户自身特点的协同创新客户选择方法,建立了产品创新要求和选择协同创新客户的指标之间的质量屋模型;基于模糊加权平均法和-截集确定评价指标权重,实现了指标权重随不同产品创新要求的动态调整;基于粗数方法提出了客户数量较多情况下确定客户在各指标上评价值的方法,计算客户评价值。案例分析结果表明,该方法具有合理性和可行性。     

收入分配公平的衡量——基于等基尼系数线的平均增长点方法研究

文章在基尼系数的基础上,提出了等基尼系数线、平均增长点等相关概念,构建了用于判断收入分配公平性的平均增长点方法,认为在等基尼系数线的条件下,平均增长点横坐标数值越大(不超过0.8时)其代表的收入分配越为理想.通过对湖南省1998、2005以及全国2005、2007年的城镇居民收入分配公平状况的实证分析,论证了基于等基尼系数线的平均增长点方法在判断居民收入分配公平状况的有效性.     

An np control chart for monitoring the mean of a variable based on an attribute inspection

This article proposes a new np control chart, called the np_x chart, that employs an attribute inspection (inspecting whether a unit is conforming or nonconforming) to monitor the mean value of a variable x. The distinctive feature of the np_x chart is using the statistical warning limits to replace the specification limits for the classification of conforming or nonconforming units. By optimizing the warning limits, the np_x chart usually outperforms the X¯ chart on the basis of same inspection cost. In addition, the np_x chart often works as a leading indicator of trouble and allows operators to take corrective action before any defective is actually produced.     

数字式平均在激光脉冲回波弱信号检测中的应用

提出了利用数字式平均的方法实现激光脉冲回波弱信号检测。详细分析了数字式平均的原理和实现方法,利用Matlab的Simulink交互式仿真集成环境设计了仿真模型,利用仿真模型和信号还原系统分析了数字式平均的次数和信噪比善比之间的关系。实验表明,该方法能有效地改善激光脉冲回波弱信号的信噪比。     

平均或加权内部收益率法有效性之证伪

解决独立性投资项目选择的一种常用的有效方法是平均内部收益率法或加权内部收益法,这似乎已成定论。本文用数值例证伪了该常用方法的有效性,间接地证明了只有坚持独立项目NPV之和最大化原则才能获得资金限额之内的最馋项目组合方案。     

Gender differentials in farming efficiency and profits: The case of rice production in the Philippines

Women make essential contributions to the agricultural and rural economies in all developing countries. Rural women are involved in a variety of production and farm management activities. In the Philippines women engage more intensively in agricultural work than men. However, Filipino women’s actual contribution to food production and the rural economy remains undervalued, if not invisible. Using the average treatment effect and farm-level data from the Philippines, this study investigates the effect of gender on farming efficiency, profits, and costs of rice production. Results indicate that female-headed farm households, despite having limited access to land, have higher values of rice production than their male counterparts. However, female-headed households have higher fixed, seed and labor input costs, consequently earning lower profits. In addition, female-headed farm households have lower irrigation costs. Findings from this study also indicate that women are less efficient in farming, but are more likely to adopt improved seed varieties.     

The performance of publicly funded startups in Romania

The purpose of this paper is to evaluate the impact of the Romanian START program, which provides public funds for establishing new firms or further developing existing firms. Using data on two waves of firms that were financed, in 2013 and 2014, which we regard as treated firms, and their corresponding firms that did not receive funding, we apply several methods aimed at revealing the impact of the program, such as matching difference-in-difference and time-varying treatment effects. Our findings show that the requirements of the program shaped the performance of the financed firms, which had higher revenues and productivity and a lower debt ratio. The impact on profit is weak, however, as the enterprises were mostly encouraged to extend their activity.     

Evolution of price effects after one-day abnormal returns in the US stock market

This paper provides a comprehensive analysis of price effects after one-day abnormal returns and their evolution in the US stock market, using Dow Jones Index over the period 1890–2018. We utilise several statistical tests and econometric methods (the modified cumulative abnormal return approach, regression analysis with dummy variables, R/S analysis (Hurst, 1951), and the trading simulation approach). The results suggest that a strong momentum effect between 1940 and 1980 after a day of positive abnormal returns was present in the US stock market, and it was exploitable for profit. However, after the 1980s this has since disappeared. Overall, price effects after one-day abnormal returns during the analysed period tend to be unstable in terms of their strength and direction (momentum or contrarian effect). Nowadays, the evidence for the price effects after one-day abnormal returns in the US stock market is weak. Our results, therefore, are consistent with the Adaptive Market Hypothesis (Lo, 2004).