时间压力对网络冲动性购买的影响研究：交易效用和感知风险的调节

以往关于时间压力对冲动性购买影响的研究结论具有两面性，即促进或抑制。文章引入交易效用和感知风险两个调节变量，通过两个实验探讨了时间压力对网络冲动性购买倾向影响的边界条件。首先，当交易效用较高时，时间压力的增加会导致其网络冲动性购买倾向的提高；而当交易效用较低时，时间压力的增加会导致其网络冲动性购买倾向的降低（实验一）。其次，当人们感知风险较低时，时间压力的增加会导致其网络冲动性购买倾向的提高；而当人们感知风险较高时，时间压力的增加会导致其网络冲动性购买倾向的降低（实验二）。研究结论可以帮助电商企业进一步了解消费者的冲动性购买行为，充分利用时间压力的影响，制定更灵活有效的促销策略。     

Smart technology and service employees’ job crafting: Relationship between STARA awareness,performance pressure,receiving and giving help,and job crafting

Owing to the rapid spread of smart technology, artificial intelligence, robotics, and algorithms (STARA), service jobs are being replaced by these technologies. Despite the potential effect of STARA awareness on employee outcomes, surprisingly few studies have explored its role service employees' work outcomes. Addressing this gap, our research assessed the mediating relationship between STARA awareness, performance pressure, and job crafting, as well as the moderating effects of help-receiving and help-giving on this relationship. We conducted a quantitative study for 301 South Korean service employees using surveys collected at two points in time. The results indicated that service employees' STARA awareness positively affected job crafting through performance pressure. Furthermore, the association between STARA awareness and performance pressure was more prominent for higher levels of help-receiving than for lower levels of help-receiving. Help-receiving further moderated the indirect effect of performance pressure on the STARA awareness and job crafting relationship. While the mitigating effect of help-giving was not supported, we observed a significantly positive association between STARA awareness and performance pressure only when help-receiving was high and help-giving was low. These findings contribute to the literature on technology in the retailing sector by uncovering how STARA awareness affects service employees’ performance pressure and job crafting and the roles played by help-giving and help-receiving in this relationship.     

薄片生产阻燃式反吹风储料器的改进设计

由于阻燃式反吹风料仓内部风力输送系统,在使用过程中容易造成风压过大,导致气流中夹带的烟粉和烟粉末在超标压力下大量外扬,通过采用增设负压装置平衡系统内气流压力的方案,有效改善了除尘效果。另外,用带分度盘的皮带传动替代了复杂的行星摆线针轮减速器,节省了投入,且操作维护简便。     

Hedging of Asian options under exponential Lévy models: computation and performance

In this paper we consider the problem of hedging an arithmetic Asian option with discrete monitoring in an exponential Lévy model by deriving backward recursive integrals for the price sensitivities of the option. The procedure is applied to the analysis of the performance of the delta and delta–gamma hedges in an incomplete market; particular attention is paid to the hedging error and the impact of model error on the quality of the chosen hedging strategy. The numerical analysis shows the impact of jump risk on the hedging error of the option position, and the importance of including traded options in the hedging portfolio for the reduction of this risk.     

基于One-Class SVM的青鳉鱼异常行为识别方法

为了更准确地解析青鳉鱼在突发污染环境中的行为变化趋势,提出了一种基于One-Class SVM模型的青鳉鱼异常行为识别方法。以青鳉鱼的生理及行为特征作为观测指标,将采集到的暴露在不同类型和浓度特征污染物下的青鳉鱼行为强度信号作为经验数据,利用直方图统计和主成分分析（PCA）对行为强度数据进行降维,实现行为特征提取,基于One-Class SVM构建模型,并以五水合硫酸铜和三氯酚作为特征污染物进行暴露实验对算法进行验证。结果表明,One-Class SVM模型可以准确地识别正常行为和污染物暴露时发生的异常行为;对于有机污染物最快可在10 min内完成预警,重金属污染物可在1 h内完成预警,并且污染物浓度越高,模型的识别效果越好。识别方法可对水源突发性水质污染进行更有效的监测和预警,也可为水污染应急决策提供技术支撑。     

高管连锁、同业监督与公司违规

本文选取2011—2018年度A股上市公司为研究样本,以具有竞争关系的同业公司间的高管连锁作为同业监督的渠道,检验了同业监督对目标公司违规的影响。研究发现:(1)同业监督能有效抑制目标公司违规倾向,且这一影响当且仅当连锁公司是同业公司时存在;(2)同业竞争是同业监督的基础,在行业集中度低和行业增长率低的行业中,同业监督对目标公司违规的抑制作用更强;(3)目标公司的政治关联会瓦解同业监督对公司违规的抑制作用;(4)区分违规行为类型后发现,同业监督对经营违规的抑制作用最强,对信息披露违规次之,对领导人违规几乎没有效果。本研究丰富了公司违规监督机制的内容,也提供了辩证看待高管同业兼任的新视角。     

一种基于Edline线特征的车道线识别算法

为了提升车道线检测的准确性和实时性,改良车道偏离预警系统的性能,提出了一种新的车道线识别算法。首先应用投影法对采集到的图像设立感兴趣区域,以此来减少图像中存在的干扰信息;其次应用一种改进后的自适应高斯滤波算法对采集所得图像进行平滑处理,减少图像中不必要的细节;最后采用边缘绘制算法进行边缘检测,在此基础上,提出一种线段检测算法——Edline算法提取边缘线,对检测到的直线段进行筛选和聚类。利用引用计数法对车道线进行跟踪和预测。结果表明,新算法的平均处理时间为17.1 ms,准确率为96.19%,将其应用在车道偏离预警系统中可以有效地提高预警效率,提升预警的准确性和响应速度。研究结果丰富了车道线识别理论,可为车道偏离预警系统的应用及基础研究提供参考。     

高职院校环境监测实践教学改革探索

本文分析了高职院校环境监测实践教学中存在的问题,从实践参与教学模式、实践教学方法及考核、评价方式等方面进行了一系列的探索和尝试。     

The untold story of commodity futures in China

We investigate the behavior of commodity futures risk premia in China. In the presence of retail-dominance and barriers-to-entry, the term structure and momentum premia remain persistent, whereas hedging pressure, skewness, volatility, and liquidity premia are distorted by time-varying margins and strict position limits. Furthermore, open interest, currency, and inflation premia are sensitive to institutional settings. The observed premia cannot be attributed to common risks, sentiment, transactions costs, or data-snooping, but are related to liquidity, anchoring, and regulation-induced limits-to-arbitrage. We highlight the distinctive features of Chinese futures markets and assess the challenges posed to theories of commodity risk premia.     

经济学视角下自然保护区有效管理行为研究——以甘肃白水江自然保护区李子坝社区为例

以甘肃白水江自然保护区李子坝社区巡护监测为例,从经济学的视角,运用比较优势和竞合模型分析该社区巡护监测与专业巡护监测的两种行为。模型分析显示两者各有优势,在专业巡护监测的基础上,如果辅之以社区巡护监测能更有效地促进环境与生物的多样性的保护,既可以提升有效管理的水平,又可以达到社区保护利益的最大化。