电气工程及其电气自动化的控制系统应用

近年来,随着我国经济的迅速发展,电气工程技术标准不断提升,对于技术的优化提出了更高的要求。电气工程技术在各行各业都得到了有效的应用,该技术的重要性不言而喻。尤其是制造业,其对于电气工程技术的依赖程度较高。所以在电气工程以及电气自动化控制系统的优化中,如何提高运行效率以及让设备稳定运行是当前工程师们所必须考虑的问题。     

Periodic strategies in optimal execution with multiplicative price impact

We study the optimal execution problem with multiplicative price impact in algorithmic trading, when an agent holds an initial position of shares of a financial asset. The interselling decision times are modeled by the arrival times of a Poisson process. The criterion to be optimized consists in maximizing the expected net present value of the gains of the agent, and it is proved that an optimal strategy has a barrier form, depending only on the number of shares left and the level of the asset price.     

Correlates of Narrow Bracketing

Behavior often deviates from standard predictions because individuals evaluate the consequences of choices separately (i.e., narrow bracketing) rather than jointly. The main existing theories classify different narrow bracketing phenomena as either (i) choice errors caused by cognitive limitations, or (ii) strategies to achieve self‐control. Using an online experiment, we find consistent evidence for theory (ii): mental budgets and narrow goals are related to each other and to measures of self‐control, but are distinct from other forms of narrow bracketing. Evidence for the complementary theory (i) is less consistent: few choice bracketing phenomena are related to each other and to cognitive skills.     

自然资源依赖对城乡收入差距的影响研究

［目的］针对全国31个省（市、区）（不含港澳台地区）、自然资源依赖度高的地区和自然资源依赖度低的地区，从整体和分区域研究自然资源依赖对城乡收入差距的影响，探究不同区域其影响程度的差异性，进而为弱化各区域城乡收入差距，解决由城乡收入差距拉大造成的各类社会矛盾具有重要的现实意义。［方法］从理论上分析了自然资源依赖对城乡收入差距的影响，并利用1999—2017年的省级面板数据，运用固定效应模型，从全国和分区域实证分析了自然资源依赖对城乡收入差距的影响。［结果］针对全国，自然资源依赖会拉大城乡收入差距； 分区域结果，针对自然资源依赖度高的地区，自然资源依赖拉大城乡收入差距； 针对自然资源依赖度低的地区，自然资源依赖对城乡收入差距影响不显著。［结论］为缩小城乡收入差距，需要降低经济体对自然资源的依赖，针对自然资源依赖度高的地区，政府通过将部分自然资源收益转化为农业创新基金和农村基础设施投入，促进自然资源收益向农村公共资本转化，完善现有的自然资源收益分配及转化制度； 鼓励资源型产业技术创新，加大研发投入，延长资源产业链； 加大农村教育投入、提升农村人力资本质量。     

Markups of Exporters and Importers: Evidence from Hungary

In this paper, we study the relationship between different proxies of firm‐level markups and trade status, using balance sheet information linked to detailed trade data from Hungary between 1995 and 2003. We find that importing is strongly positively correlated with markup measures, both across and within firms. We argue that this correlation can reflect three channels: self‐selection, higher physical productivity resulting from access to a larger variety of inputs, and quality upgrading based on high‐quality imported intermediate inputs. We present evidence for the relevance of the third channel by showing that importers’ markup premium is higher when inputs arrive from developed countries, and that importing is correlated with higher‐quality (price‐adjusted revenue) exports. We find no robust evidence for exporter premium when controlling for importing. We argue that the non‐existent exporter premium might result from the stronger competition in export markets relative to domestic markets.     

You say you want a (Rose) Revolution? The effects of Georgia's 2004 market reforms

After Georgia declared its independence from the Soviet Union, it experienced civil war and strife for more than a decade. In late 2003, the peaceful Rose Revolution installed a new government that began a series of radical market‐liberal reforms. However, the effectiveness of these reforms was controversial. We offer a rigorous evaluation of these reforms via the synthetic control method which creates a credible counterfactual. Compared to the synthetic controls, we find that the reforms enacted after the Rose Revolution led to significant improvements in Georgia's social and economic development, albeit with temporary side effects and argue that this case provides some support for the effectiveness of rapid, multidimensional reform.     

Interpretive structural modeling of quality factors in both medical and hospitality services in the medical tourism industry

This study aims to theoretically integrate quality factors of both medical and hospitality services in medical tourism. Medical tourism comprises both medicine and tourism. Although the core product in medical tourism is medical treatment, attractive hospitality and travel options are also essential. Despite the dual nature of medical tourism, the two aspects of this concept have not been integrated in a unique framework. This study attempts to fill this gap using interpretive structural modeling (ISM). According to ISM, although factors of medical services and hospitality services are independent from each other, these factors have vital impacts on perceived value, satisfaction, and loyalty.     

Using paradata to collect better survey data: Evidence from a household survey in Tanzania

Data are a key component in the design, implementation, and evaluation of economic and social policies. Monitoring data quality is an essential part of any serious, large‐scale data collection process. The purpose of this article is to show how paradata should be used before, during, and after data collection to monitor and improve data quality. To do this we use timestamps, global positioning system (GPS) coordinates, and other paradata collected from an 800‐household survey conducted in Tanzania in 2016. We demonstrate how key paradata can be used during each phase of a research project to identify and prevent issues in the data and the methods used to collect it. Our results corroborate the importance of collecting and analyzing paradata to monitor fieldwork and ensuring data quality for micro data collection in developing countries. Based on these findings we also make recommendations as to how researchers can make better use of paradata in the future to manage and improve data quality. We argue for an expansion in the understanding and use of varied paradata among researchers, and a greater focus on its use for improving data quality.     

"利剑斩污"行动下石家庄市挥发性有机物的污染特性变化研究

为研究石家庄市在"利剑斩污"行动管控期和非管控期挥发性有机物(VOCs)的污染特性变化,在2个时间段内对石家庄市3个国控点进行采样分析。通过苏玛罐(SUMMA罐)进行样品采集,利用气相色谱/质谱联用(GC/MS)仪对石家庄市区3个国控点的VOCs进行定性定量检测分析。结果表明,监测期间主要的特征污染物是二氯甲烷、二氯丙烷、苯和甲苯。与非管控期间相比,管控期间各污染物的质量浓度均有所降低,总VOCs平均质量浓度降低45.107μg/m~3,二氯甲烷质量浓度降低8.796μg/m~3,二氯丙烷质量浓度降低3.750μg/m~3,苯质量浓度降低18.285μg/m~3,甲苯质量浓度降低16.895μg/m~3。大气环境调控策略的实施,有效降低了VOCs浓度,减少了空气污染程度,空气质量改善效果显著。"利剑斩污"行动期间采取的相关举措,对于制定常态化下VOCs的防治对策具有一定的参考价值。