A Machine Learning Analysis of the Recent Environmental and Resource Economics Literature

We use topic modeling to study research articles in environmental and resource economics journals in the period 2000–2019. Topic modeling based on machine learning allows us to identify and track latent topics in the literature over time and across journals, and further to study the role of different journals in different topics and the changing emphasis on topics in different journals. The most prevalent topics in environmental and resource economics research in this period are growth and sustainable development and theory and methodology. Topics on climate change and energy economics have emerged with the strongest upward trends. When we look at our results across journals, we see that journals have different topical profiles and that many topics mainly appear in one or a few selected journals. Further investigation reveal latent semantic structures across research themes that only the insider would be aware.

     

Three decades of research on corporate governance and R&D investments: a systematic review and research agenda

This paper reviews and systematizes the empirical research on the nexus between corporate governance (CG) and investments in research and development (R&D) published in leading business, management, economics and finance journals over the past 30 years. We find that CG is key in shaping R&D investments. Moreover, the effects of both firm- and country-level CG are important for both internal and external R&D investments. Drawing on our review, we welcome future studies to examine the effect of the interplay between various CG mechanisms and different types of R&D investments, and possibly identify mediating variables besides the moderating ones. Moreover, we highlight the need for future interdisciplinary studies, as well as investigations of private companies and across developing countries. Whenever causal interpretations are attempted, both sample selection and endogeneity problems should be addressed, along with testing the CG-R&D investment nexus for nonlinear dynamics. The implications of the study for both theory and practice are also discussed.     

Investment opportunities and R&D investments in family and nonfamily firms

The firm’s investment opportunity set (IOS) reflects the prospective growth opportunities related to physical and human capital investments. IOSs are largely firm specific, embedded in assets-in-place, or generated by experience curves, learning-by-doing, and other similar phenomena. However, the value of an IOS can be destroyed if a firm does not exercise the option to invest. In this study, we theorize that a firm’s ability to invest in R&D is conditional on the availability of a favorable IOS. We test our theoretical propositions in the European business environment using a sample of large publicly traded firms with concentrated ownership. Our findings support the notion that the IOS is a significant determinant of corporate R&D investments, but the magnitude of this effect depends on the identity of the ultimate owner. Specifically, the sensitivity of R&D investments of family- and state-owned corporations is higher to favorable IOS than that of widely held corporations, suggesting these firms are more responsive to favorable IOS than others. By introducing the IOS dimension, our results have interesting implications for both theory and practice.     

基于改进Transformer模型的文本摘要生成方法

传统的文本摘要方法，如基于循环神经网络和Encoder-Decoder框架构建的摘要生成模型等，在生成文本摘要时存在并行能力不足或长期依赖的性能缺陷，以及文本摘要生成的准确率和流畅度的问题。对此，提出了一种动态词嵌入摘要生成方法。该方法基于改进的Transformer模型，在文本预处理阶段引入先验知识，将ELMo(Embeddings from Language Models)动态词向量作为训练文本的词表征，结合此词对应当句的文本句向量拼接生成输入文本矩阵，将文本矩阵输入到Encoder生成固定长度的文本向量表达，然后通过Decoder将此向量表达解码生成目标文本摘要。实验采用Rouge值作为摘要的评测指标，与其他方法进行的对比实验结果表明，所提方法所生成的文本摘要的准确率和流畅度更高。     

险资股权投资的结构性改革研究*——基于险资投资的倒U型效应分析

保险资金作为重要的机构投资者能否发挥促进公司绩效提升的作用在已有研究和监管政策制定上都存在较大争议。本文以2005-2017年A股上市公司为研究样本，发现险资持股比例对上市公司绩效以及估值影响存在显著的倒U型曲线效应，相应机制研究表明险资持股通过显著影响两类代理成本的渠道发挥治理作用。在适度持股比例以下，险资增持能够降低被投资公司管理费用率和其他应收款占比，并提高资产周转率，从而降低两类代理成本；持股超过一定比例反而造成两类代理成本上升。险资持股比例变化对保险机构调研次数的影响则从公司治理参与角度印证了以上结论。对倒U型曲线效应的深入分析既有助于深化对机构投资者影响公司绩效的多重效应和机制的认识，同时为在金融机构层面落实金融供给侧结构性改革、增强险资服务实体经济能力提供参考。     

互联网对企业协同创新中知识增值的影响——软创新资源的作用

互联网环境下协同创新中的知识增值运行机制发生重大改变。从知识流视角出发，整合资源基础观与知识基础观，在完善软创新资源概念的基础上，通过对4个案例的深入探索，分析软创新资源各维度对协同创新知识增值的影响。结果表明，互联网的群智性、泛在性等特点可以孕育出软创新资源，进而影响协同创新中的知识增值。其中，软创新资源包括开放型信息资源、协同型关系资源、创新型文化资源以及技术型能力资源4个维度，并分别作用于知识获取、知识转移、知识创造和应用，从而实现知识增值。最后，针对如何最大程度地发挥互联网在促进知识增值方面的作用，提出相关建议。     

Gender differences in Russia's job mobility and its rewards*

This article considers age and gender differences in the probability and consequences of job mobility in Russia. Little is known about who is mobile and whether mobility impacts wages once the characteristics of movers are controlled for. Results show a gender difference in the likelihood of exit but not promotion. Results also show that promotions have a positive effect only on the wages of young women, but young men's wages are not affected. Further, young men see a significant decrease in wages following an exit, while young women are not affected by firm exit. The article shows that early mobility is particularly important for women, who earn less overall. Results help to understand processes of inequality in wages and conditions that occur due to sorting, and the importance of promotions as ‘life chances’ which lead to ‘career-track jobs’. Gender differences in securing such life chances may help to understand gaps in earnings, which emerge later.     

基于主成分分析法的地铁运营关键绩效指标体系研究

目前国内研究尚缺乏一套科学的、系统的、有效的对地铁运营的评价体系.本文以成都地铁为研究对象,采用问卷调研法,将16个初级指标做成问卷让受访者进行打分,之后将数据导入SPSS软件,分析其效度与信度,剔除信度较低的指标,最终获得3个一级指标和15个重要的二级评价指标,并以此构建出一套对地铁运营绩效的评价指标.最后通过对受访者问卷的打分情况,分析出乘客看重哪些因子,并以此向相关部门提出建议.     

海康威视轻资产运营模式转型的财务绩效评价

轻资产运营模式是一种以较低有形资产规模获取较高企业价值的商业模式,近年来受到广泛关注.在这种价值驱动的新型资本战略模式下,企业流动资产尤其是现金类资产较多,固定资产和存货相对较少,企业将更多资金投入到技术、品牌、营销等高附加值环节,通过"轻"资产形态来获取"高"利润回报,并提升财务绩效.本文以实施轻资产运营模式转型战略的海康威视作为案例分析对象,运用纵向案例研究方法分析海康威视轻资产运营模式转型的动因和运营效果,运用财务战略矩阵模型探究轻资产转型对其财务绩效的影响,并针对轻资产运营模式转型过程中存在的问题提出相应对策建议,以期为相关企业进行轻资产运营模式转型提供有益的借鉴.     

基于库存理论的铁路始发直达运输产品设计

将库存理论运用到铁路始发直达运输产品设计,能够有效实现运输服务组织成本与库存成本的有机统一。为实现库存成本在铁路始发直达运输中的加载,在考虑周期非完整情况下的库存成本的同时,将铁路运输和库存成本纳入同一目标函数,在装卸车地库存能力约束下,构建基于库存理论的铁路始发直达运输产品设计模型,确定成本最小的铁路始发直达运输产品设计方案。以赤峰地区至山东省煤炭运输网络为例,设计方案有效降低了成本,有助于吸引客户选择铁路运输,以及辅助铁路运营单位研究调整始发直达运输产品方案。