成也萧何,败也萧何？——高管金融经历与公司债券融资

基于印记理论和高层梯队理论,本文以2008至2018年发行公司债券的上市公司为研究对象,考察高管金融经历对公司债券融资的影响机理。结果表明:首先,高管金融经历在提高公司债券发行成功率的同时也会增加债券融资成本和违约风险,而对发债规模与期限并不会产生显著影响,在控制可能的内生性问题后结论依然成立;其次,具有金融经历的高管所任职公司会通过盈余管理来提高债券发行成功率,但也会增加债券的融资成本和违约风险;最后,具有证券公司或商业银行工作经历的高管对公司债券融资的影响更为显著。本文有助于实务界和理论界理解高管异质性特征对公司债券融资的影响机制,为监管部门制定防范金融风险的政策提供可靠的理论依据。     

供应商回购承诺下的销售商存货质押融资决策

研究由一个供应商和销售商组成的供应链。销售商为中小企业,在受资金约束时无法通过自身信用获得所需融资,此时供应商可以为销售商贷款提供担保以提高其融资授信额度。本文采用销售商违约后剩余质押物的回购率来衡量供应商对融资风险的分担程度,对参与各方的存货质押融资决策进行了深入研究。结果表明:供应商的回购承诺提高了银行利润,在一定条件下提高了银行的质押率;并且,有回购承诺的融资决策在市场前景乐观情况下可以有效缓解销售商的融资困境。     

Exploring MLD in mathematics education: Ten years of research

Mathematical learning disabilities or difficulties (MLD) are an increasing source of educational inequalities. This article explores research about MLD in Mathematics Education over the past ten years. The methodology focuses on specific, validated keywords. These keywords are used to identify articles in leading journals in mathematics education. Our work makes several new contributions to the field of mathematics education, notably: a reusable methodology and keywords for a literature review; an exhaustive list of articles about MLD in leading mathematics education journals; a discussion of the definitions and features of MLD used in these articles; and a tool to classify research dealing with MLD (categories that characterize students with MLD). We also highlight some unexplored dimensions regarding MLD in Mathematics Education research.     

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This paper assumes that company's asset process follows a non-linear model, which reflects the relationship between the operation costs and the size business. Suppose that the company can control the asset process by changing the size of business, paying dividends and raising money dynamically. Meanwhile, it bears both fixed and proportional transaction costs during the control processes. Under the objective of maximizing the company's value, we obtain the explicit solutions of optimal strategies and value function by using the optimal control method. The results illustrate that the optimal strategies depend on the parameters of the model. The company should expand the business scale with the increasing of asset. Dividends should be paid out according to the impulse control strategy. Financing is profitable to avoid bankruptcy if and only if the transaction costs are relatively low.     

存货质押融资中考虑银行Downside-risk的回购契约设计

本文研究供应链金融中存货质押融资模式下回购契约的设计问题,即在需求不确定和银行下侧风险(Downside-risk)规避的前提下,通过对契约合同中变量范围的控制实现供应链的协调。文中首先给出了考虑银行利息与风险规避在内的供应链契约模型,然后分别分析了银行下侧风险控制模型下供应商的促销成本分担比例的下限值和在不减少供应商期望收益原则下该比例的上限值,最终得出该下限值由银行下侧风险控制指标和质押量共同决定,而当销售商的订购量越多时,供应商愿意接受的努力成本分担比例上限值也越大,并给出相应的上下限值。     

Do students really understand what an ordinary differential equation is?

Differential equations (DEs) are important in mathematics as well as in science and the social sciences. Thus, the study of DEs has been included in various courses in different departments in higher education. The importance of DEs has attracted the attention of many researchers who have generally focussed on the content and instruction of DEs. However, DEs are complex issues that students may find difficulty to understand. The limited research in this literature points to the need for more studies on students’ conceptions, and understanding of DEs and their basic concepts. The objective of this study is to fill this need by revealing the understanding, difficulties and weaknesses of the students who are successful in algebraic solutions, in relation to the concepts of DEs and their solutions. For this purpose, 77 students were asked 13 DE questions (6 of them about algebraic solution, and the rest about interpreting DEs and their solutions). From an analysis of the students’ answers, it was concluded that the students who were quite successful in algebraic solutions, indeed did not fully understand the related concepts, and they had serious difficulties in relation to these concepts.     

电子商务企业的金融支持体系研究-基于资金供给与需求的分析

电子商务企业作为创新型的网络企业,具有高风险高预期收益的特点,"融资难"问题伴随着电子商务企业发展的整个过程.以电子商务和融资的相关理论为基础,在把握当前国内外电子商务的发展特点以及融资中所存在的问题基础上,从资金供给与需求的均衡分析对电子商务企业金融支持进行研究,并对中国电子商务企业融资难问题提出了相应的政策建议.     

出口海陆仓融资决策多目标优化模型与算法

授信额度分配决策是出口海陆仓融资业务中的重要问题,为权衡该项业务中的风险和收益,综合考虑出口国家政治风险、风险价值约束以及信用风险等因素,构建以收益最高和风险最低为目标的优化模型。针对所构建模型的特点,提出一种将模拟退火与NSGA-II算法相结合的混合算法对模型进行求解。最后,通过具体实例,分别以现实中常见的1~5个月质押期为例,验证了模型和算法的适用性及有效性。     

基于质押贷款下的库存管理问题的研究

库存决策不仅受需求、运输费用、储存费用的影响,而且企业本身的资金状况也会限制企业实施库存管理.以报童模型为原型,讨论了企业存在道德风险的情况下,以仓单质押方式融资的企业的库存管理决策.假设企业是风险中性的并且商品的储存费用不小于商品的处理价格.研究发现,只有质押库存比较小的企业才会用掉所有的贷款限额.并且随着贷款价值比的增加,企业有可能保留部分资金,而使用贷款增加库存.     

Interior of a Schwarzschild Black Hole Revisited

The Schwarzschild solution has played a fundamental conceptual role in general relativity, and beyond, for instance, regarding event horizons, spacetime singularities and aspects of quantum field theory in curved spacetimes. However, one still encounters the existence of misconceptions and a certain ambiguity inherent in the Schwarzschild solution in the literature. By taking into account the point of view of an observer in the interior of the event horizon, one verifies that new conceptual difficulties arise. In this work, besides providing a very brief pedagogical review, we further analyze the interior Schwarzschild black hole solution. Firstly, by deducing the interior metric by considering time-dependent metric coefficients, the interior region is analyzed without the prejudices inherited from the exterior geometry. We also pay close attention to several respective cosmological interpretations, and briefly address some of the difficulties associated to spacetime singularities. Secondly, we deduce the conserved quantities of null and timelike geodesics, and discuss several particular cases in some detail. Thirdly, we examine the Eddington–Finkelstein and Kruskal coordinates directly from the interior solution. In concluding, it is important to emphasize that the interior structure of realistic black holes has not been satisfactorily determined, and is still open to considerable debate.