组合负荷预测方法综述

电力系统负荷具有很多不确定因素,针对单一模型进行负荷预测时,预测精度不高这一问题,可采用组合预测法将多种预测方法所得的预测值进行加权平均而得到最终预测结果,以满足现代电力对负荷预测结果的准确性、快速性和智能化的要求。该文首先简要介绍了几种常用的负荷预测方法,接着详细介绍了组合负荷预测的研究现状及确定组合预测中各模型最优权重的几种方法,最后介绍了组合负荷预测模型的误差修正方法,对提高负荷预测的准确性有一定的现实意义。     

高校教师参与学生评教模式的研究

学生评教已成为当前高校管理部门监控教师教学质量的主要手段,然而当前高校普遍采用的学生评教模式存在评价指标不科学、评教时间把握不准确、管理措施不合理等缺陷,导致评教结果出现大的偏差。本文设计的评教模式将教师引入学生评教活动,巧妙地解决了上述缺陷,使评教过程更加人性化,评教结果更加可信。     

Ownership structure and firm performance: Evidence from the Chinese corporate reform

We employ a new classification of ownership identity to analyze the impact of ownership structure on enterprise performance in China. Using both fixed effects model and Generalized Methods of Moments (GMM), this study finds that marketized state-owned enterprises outperform firms controlled by the government, indicating that partial privatization of state-owned Chinese firms improves corporate governance. Non-controlling large shareholders of marketized state-owned enterprises and private enterprises are found to play active roles in corporate governance. Lastly, there is evidence that ownership concentration of a controlling shareholder decreases the incentives to expropriate minority shareholders.     

要素价格扭曲、内需增长与企业出口竞争力提升

企业出口不仅取决于国际市场的供求关系,而且受到国内市场环境的影响。要素价格扭曲导致的资源错配会对出口企业产生不利影响,进而有损其出口竞争力。然而,现有文献较少研究要素价格扭曲对企业出口竞争力的影响及其传导机制,尤其缺乏相关经验分析。本文通过构建一个包含“扭曲税”的理论框架分析要素价格扭曲与企业出口竞争力的关系,认为：要素价格扭曲会阻碍企业间的资源再配置,削弱更替竞争的效率提升效应,使得大量低效率企业不能进行市场出清,同时还会抑制企业的技术创新行为,进而不利于企业通过效率提升和技术进步来提升出口竞争力。同时,国内需求增长产生的本地市场效应、需求引致创新效应、经济集聚效应等不仅能促进企业出口竞争力提升,还会弱化要素价格扭曲对企业出口竞争力的负面影响。采用中国1999—2007年工业企业以及2007—2020年上市公司数据的分析发现：企业的要素价格扭曲（包括资本价格扭曲和劳动价格扭曲）程度与其出口竞争力显著负相关,同时,要素价格扭曲程度与企业的市场退出和技术创新概率也显著负相关,表明要素价格扭曲会显著抑制企业出口竞争力的提升,其中存在阻碍低效率企业市场退出和抑制企业技术创新的传导路径;内需增长对企业出口竞争力具有正向影响,且能显著弱化要素价格扭曲对企业出口竞争力提升的抑制作用;要素价格扭曲对企业出口竞争力的负向影响存在企业异质性和地区异质性,表现为资本价格扭曲对融资约束较低的外资企业和国有企业影响更为显著（相比私营企业）,而劳动价格扭曲对劳动报酬占比较低的私营企业和外资企业影响更为显著（相比国有企业）,要素价格扭曲对市场化程度较低地区的企业影响更为显著;此外,劳动价格扭曲对企业出口竞争力的负向影响比资本价格扭曲更大。相比于以往文献,本文拓展和深化了要素价格扭曲的经济效应以及企业出口竞争力的影响因素研究,并从内需增长的角度为深入认识要素价格扭曲与企业出口竞争力的关系提供了新思路,也为要素价格扭曲的企业出口竞争力抑制效应及其微观机制提供了经验证据。根据本文的研究结论,各地应持续深化各领域的市场化改革,加快构建全国统一大市场,实施扩大内需战略,切实缓解各类微观经济主体（尤其是私营企业）的融资约束,并持续提高劳动报酬在初次分配中的占比。     

基于Solidworks模块化机械产品动态仿真研究

本文介绍了利用Solidworks模块motion对机械产品进行仿真运动,输出某些参数曲线,为以后的现实应用提供数据,仿真的目的在于不必制造昂贵的样机,节省资源,准确分析机械运动。     

如何提高砂卵石含水层供水管井施工效率与成井质量

文章阐述了第四系(砂、卵石)供水管成井工艺施工流程与供水管井成井质量的影响因素,通过工作实践,提出了供水管井成井的技术措施。     

Q/V频段5G基站对NGSO星座系统地球站的干扰分析

针对Q/V频段5G基站对非静止轨道（Non-geostationary Orbit,NGSO）星座系统地球站的同频干扰问题,提出了一种5G毫米波系统与NGSO星座系统下行链路间的干扰分析方法。结合NGSO星座系统地球站天线指向的时变性,建立了基于时间离散的“拉远式”和“挖洞式”的动态干扰分析模型,并从强度和集总效应两个维度综合评估了系统之间的干扰情况。以OneWeb系统为例,仿真分析了不同保护距离下5G基站对OneWeb地球站的干扰情况。结果表明,在Q/V频段,当保护距离为50 m时,95%的时间内干扰余量不小于15.38 dB,5G基站与NGSO星座系统地球站有兼容共存的空间。     

拉西瓦水电站自动化设备运行分析和控制逻辑完善

简要分析了拉西瓦水电站监控系统电气和机械事故处理流程的本质区别与故障后处理方式的不同;对一次调频、AGC控制存在的问题进行了优化协调;并对压油装置控制逻辑存在的问题进行了修改完善。     

Vertical trade and China's export dynamics

This paper examines how China's exports are affected by exchange rate shocks from countries that supply intermediate inputs to China. We build a simple small open economy model with intermediate goods trade to show that due to the intra-regional trade in intermediate goods, a devaluation of other Asian currencies does not necessarily hurt China's exports, as imported intermediate goods could become cheaper. The effect of intermediate goods costs depends critically on the share of intermediate goods used in China's export goods production and the degree of exchange rate pass-through in imported intermediate goods prices. If prices for intermediate goods are not very sticky, the effect through this channel could be large, and China's exports could even benefit. We find that these findings do not depend on China's choice of currency invoicing between the RMB and the US dollar or the choice between fixed and flexible exchange rate regimes.     

Factors determining the use of nutrition labels: The case of Malaysia

The rising prevalence of diet-related illnesses, the most visible of health problems, in both developed and developing countries has become a serious public health concern. Nutrition labeling plays an important role in promoting healthy diet and, thus, in improving population health. The objective of the present study is to investigate how socioeconomic factors—age, income, gender, education, marital status, house locality and employment status—affect the use of nutrition labels among Malaysian adults. The Third National Health and Morbidity Survey of Malaysia, which consisted of 34,539 respondents, is used for analysis. A logit model is developed to examine the probability of using nutrition labels. Evidence from the present study shows that age, income, gender, education, and marital status are significantly associated with the use of nutrition labels. In particular, age reduces the likelihood of using nutrition labels, while high income earners, females, the well-educated, and married individuals are more likely to use nutrition labels. The findings of the present study suggest that differentiated targeted efforts should be used on the various population groups identified when implementing programs and activities promoting the use of nutrition labels.