Network effects,trade, and productivity

We consider network effects in the monopolistically competitive model of trade developed by Melitz and Ottaviano (2008). We show that a larger network effect intensifies competition by allowing more‐productive firms to raise prices and earn higher profits, but forcing less‐productive firms to reduce prices and earn lower profits. As a result, low‐productivity firms are driven out of the market. We also show that when network effects are asymmetric, it may be difficult for firms from a country with a small network effect to compete with firms from a country with a large network effect.     

不完美碰撞检测的CSMA/CA协议性能分析

传统中低轨小卫星群的移动自组织网络中，卫星采用半双工载波侦听/碰撞规避协议（Carrier Sensing Multi-access/Collision Avoidance,CSMA/CA）接入控制信道。为避免半双工模式“盲听”对碰撞感知存在的延时，提升接入效率，卫星需要工作在碰撞检测和数据接收同步进行的全双工模式；同时由于卫星通信特点，残余自干扰带来的不完美碰撞检测不可忽略。针对以上需求，设计了一种全双工CSMA/CA协议，对接入流程和参数进行了详细描述；研究了自干扰抑制度和检测门限等与虚警率、漏检率的数学关系；推导了系统吞吐量的解析表达式，并仿真探究了初始竞争窗口长度等参数的优化设计准则。仿真结果表明，通过合理选取参数，该协议能在存有不完美碰撞检测的情况下，实现吞吐量的提升。     

The impact of corporate fraud on director‐interlocked firms: Evidence from bank loans

We examine the impact of corporate fraud committed by one firm (the “fraudulent firm”) on other firms with interlocking directors (the “interlocked firms”), focusing on the debtholder side. We argue that the revelation of a fraudulent firm's fraud can damage the reputation of the interlocked firms because corporate governance can propagate via director interlocks. Empirically, we find that the interlocked firms' cost of debt is higher and the loan covenants become stricter after the fraud cases of the fraudulent firms are revealed. Consistent with the corporate governance propagation explanation, our results are weaker (stronger) for interlocked firms that have better (worse) pre‐event corporate governance standards. Our findings suggest that corporate fraud of fraudulent firms can affect other firms through director‐interlocks beyond shareholder value.     

Pyramidal structure,risk‐taking and firm value

This article investigates the relationship among pyramidal layers, risk‐taking and firm value using a sample of local state‐owned enterprises (SOEs) in China. We find that state‐pyramidal layers have a positive and significant impact on firm risk‐taking and firm value, suggesting that the pyramidal structure formed by the state protects SOEs from political intervention. Risk‐taking is conducive to enhancing firm value and is one of the important channels through which state‐pyramidal layers increase firm value. By exploring the role of state‐pyramidal organizational structures in improving SOEs' risk‐taking, our results contribute to both corporate governance and corporate finance literature.     

中国艺术品贸易发展现状及对策研究

改革开放以来,中国艺术品市场作为一个较大的文化艺术和经济体系愈渐壮大,已经占据全球艺术品三大市场之一的地位.同为全球艺术品三大市场成员的美国与英国的艺术品的市场体系已相当成熟,然而中国的艺术品市场体系并不完善,贸易市场仍存在一些不合理的现象.中国艺术品贸易规模存在下降趋势,国际贸易份额较低,虽然艺术金融及其产业规模在不断上升,但是与英美相比,金融化程度较低,且在国际艺术品市场中的贸易竞争力不足.此外,中国艺术品市场存在诚信不足、评估鉴定体系不合理、专业人才缺失且进口关税较高等问题.中国艺术品要想继续发展强大,需从艺术品市场观念、艺术品市场环境以及中国化市场道路等方面做出改变及提升.     

企业家心理韧性对企业成长的影响——探索式创新与社会连带的中介调节作用

利用新兴视频测量技术对企业家心理韧性强度进行测量，并以2015-2017年中国213家A股上市公司面板数据为研究样本，实证分析企业家心理韧性对企业成长的作用关系，并探讨在该作用关系中探索式创新及社会连带的影响效应。研究结果显示：企业家心理韧性对企业成长有显著正向影响；企业探索式创新在企业家心理韧性与企业成长之间存在部分中介作用；社会连带正向调节企业家心理韧性对探索式创新的促进关系。当企业家社会连带水平较高时，企业家心理韧性对探索式创新意愿的促进作用更强，对企业成长的积极影响更显著。     

Factors contributing to injury severity in work zone related crashes in New Zealand

Roadworks take place frequently on existing roads in New Zealand. The adverse effects of poor road conditions and reduced road width due to the presence of a work zone on the safety of road users and workers at the work zone have been a matter of concern. Several studies have been conducted to examine the risk factors contributing to the occurrence of road crashes in work zones in different countries. Slow-moving and stopped vehicles near work zones have been found to be the primary cause of crashes and casualties in the work zones. Excessive speed of passing traffic has also been recognized as a crucial factor contributing to work zone related crashes in New Zealand. This study examined the effect of possible risk factors contributing to severe injury and fatality in work zone related crashes in New Zealand. A multinomial logistic regression model was established to determine the association between crash severity and factors such as road environment, vehicle attributes, driver behavior, and crash circumstances, based on the information available on 453 road crashes during the period from 2008 to 2013. The results indicated that the time period, vehicle involvement, and presence of vulnerable road users were the factors that determined the crash severity in work zones. This implies that improvements are required in traffic control and management measures in work zones to enhance road safety in the long run.     

公共安全管理专业“双师型”教师队伍建设刍议——针对高职院校

公共安全管理专业是培养掌握基本专业知识和能够对突发事件立即作出反应的人才。目前我国公共安全管理专业存在有实际行业从业经验的教师比例偏少,兼职教师队伍满足不了高职院校发展的需要,公共安全管理专业双师型教师培养基地缺乏,双师型教师的考评体制不健全等问题。依据培养目标的要求,针对有关问题,当前加强高职院校公共安全管理双师型教师队伍建设,应该培养和建立一支专兼职结合的公共管理专业师资队伍,探索"双师型"教师成长规律,创新"双师型"教师培养机制,加快高等职业院校"双师型"教师培养培训制度建设,把高职院校公共安全管理专业"双师型"教师队伍建设作为一项经常性工作,与时俱进地常抓不懈。     

新兴市场海外并购的持续创新效果及影响因素研究

新兴市场企业海外并购，购买技术的同时能否提升其创新能力？以中国A股上市公司为对象，研究技术并购行为对企业技术创新的影响及持续效果。不仅考虑了海外并购事件，还考虑了并购之后的吸收过程与技术创新的关系。研究发现，中国企业能够通过海外并购促进其技术创新绩效显著提高，但长期来看，海外并购对其创新能力的促进作用逐步减弱。国有企业能够通过海外并购获得更高的创新绩效，并且该效果能保持更长时间。具有海外经历的高管也能够帮助企业从海外并购中获得更高的创新绩效，但海归高管不利于该效果的长期保持。     

员工就业能力、职业自我效能感、工作不安全感对主观职业生涯成功的影响

本研究旨在考察企业员工就业能力对主观职业生涯成功的影响,以及职业自我效能感和工作不安全感在二者间的可能中介机制.在对470位企业员工进行两轮问卷调查的基础上,采用结构方程模型对数据进行分析.结果表明:(1)就业能力可以直接正向影响工作满意度和职业生涯满意度这两个主观职业生涯成功的核心方面;(2)就业能力可以分别通过职业自我效能感、工作不安全感以及二者的链式中介而间接影响工作满意度;(3)就业能力可以分别通过工作不安全感以及职业自我效能感、工作不安全感的链式中介而间接影响职业生涯满意度.