【作者】 许琼来；

【导师】 唐守廉；

【作者基本信息】 北京邮电大学 ， 管理科学与工程， 2008， 博士

【摘要】 根据中国互联网络信息中心（CNNIC）的统计:中国网民数增长迅速,截至2007年底,中国网民人数2.1亿人,年增长率53.3%,位居世界第二位。高速发展的互联网迅速渗透到中国经济、政治、文化等社会生活的各个领域,掀起了一场积极而深刻的社会变革。但是,我国互联网在持续高速发展的同时,相关问题也如影随形,由于网络环境的虚拟性,诸如网络欺诈、垃圾邮件、恶意软件等问题层出不穷,在网络交易中,经济活动呈现多重不确定性——信息质量不确定性、交易对象不确定性、交易手段不确定性、商业信用不确定性等,网络交易中的欺诈、犯罪问题更为突出,网络环境特别是网络交易环境中面临普遍的信任缺失,网络交易信任的提升成为函待解决的问题。网络交易信任缺失的影响因素是多方面的,既有网络自身的原因,又有网络运行和存在的外部环境——现实社会的原因,主要体现在道德、法律制度和信息三个层面,本研究主要基于信息层面的影响因素,从解决信息不对称的角度,在已有网络交易信任研究成果的基础上,结合博弈理论,构建了网络交易的不完全信息静态博弈模型、KMRW声誉模型、信号传递模型和委托代理模型,得出了若干有价值的结论,并提出了降低网络环境中信息不对称,减小风险,增强网络交易信任的政策建议。首先本文在信任文献综述中分别回顾了传统信任理论和网络交易信任理论,重点介绍了信任的定义,多学科对信任的认知,信任的分类,网络信任的概念,网络信任的影响因素——网络主体、关系人及环境,以及网络信任的研究模型——理论模型、实体模型和实证模型,为下文的研究提供了基本依据和出发点。随后,本文以博弈理论分析了网络交易中的逆向选择问题,指出在网络交易的不对称信息条件下,无论买卖双方的认知程度,网络交易中都存在逆向选择。为此,文章分别从网络交易涉及的网络主体（买家）、关系人（卖家）、环境（监管者和第三方中介）三个方面构建博弈模型探讨降低信息不对称的途径以提升网络信任:1、从网络主体角度构建的网络交易的不完全信息静态博弈模型探讨了网络交易中涉及交易保障的相关问题,指出进行网络交易时,要求更多的商家参与,买家尽量集中购买都能使得商品标价趋近于其自身成本,从而降低信息不对称的负面影响,提高网络交易的效率,增强网络信任,并据此提出了降低市场准入门槛、统一行业信息、门户网站购物、应用搜索引擎、集中购买商品等政策建议;2、从关系人角度构建的网络交易的KMRW声誉模型说明在一定条件下,交易博弈双方都将为了获取长期利益最大化而放弃短期利益从而坚持合作策略,并指出网络买家受到欺诈时的损失越小,买卖双方成功交易后买家的收益越大,网络交易任意一方欺诈而另一方诚信的情况下网络卖家效用的绝对值越大,卖家非理性概率ρ越小,都能导致长期的合作行为,据此,提出建立网络中消费者权益保障机构和保险机制,加快网络交易立法等政策建议并重点指出网络交易中的网络卖家承担不确定性风险有助于降低信息不对称的影响;3、从环境因素中网络监管者角度构建的网络交易的信号传递模型分析了网络交易中信号传递的条件和均衡结果,指出在网络交易中网络监管者的作用关键在于确保信号传递机制的顺畅,即降低质量好商家提升信誉等级的成本,增加质量差商家提升信誉等级的成本,使得网络中的信誉等级起到传递商品信息的作用,在此情况下,卖家和买家有两个分离均衡,其支付函数（收益）分别为:(P_H-C_G-C_Gr,V_G-P_H)、(P_L-C_B-C_BT,V_B-P_L)(其中P_H和P_L分别为买家对不同质量商品的出价,P_H＞P_L,C_H和C_B分别为不同质量商品的成本,C_G＞C_B,C_GT和C_BT不同网络商家累积信誉的成本,C_GT＜C_BT,V_G和V_B为不同质量商品对买家的效用,V_G＞V_B),围绕着信号传递机制,提出了建立网络征信系统、制定信誉评级体系、建立失信惩戒机制、保护网络知名品牌、推广移动互联网等一系列政策建议;4、从环境因素中网络第三方角度构建的网络交易的委托代理模型分析了在网络交易中引入第三方的相关问题,指出在信息不对称情况下,中介的最优努力水平小于对称信息下的努力水平,买家的期望收入小于信息对称时的期望收入,中介越是风险规避,努力的负效用越大,产出的不确定性越强,中介努力工作的边际收益越小,中介努力的边际成本只与产出分享系数β和χ有关,是产出分享系数的增函数,通过将可观测的外生变量z写入合同,一方面可以提高中介分享的剩余份额,从而提高合同的激励强度,剔除外部环境的影响,另一方面也可以减少中介承担的风险,根据第三方努力程度的影响因素及其风险偏好的差异提出了实行中介资质认证、建立中介分级体制和建立网络环境评价体系等政策建议。最后,对本论文作了总结与研究展望,主要归纳了论文的理论创新与实践意义以及本研究的不足与未来的研究方向,提出对网络交易信任的进一步研究应以实证为支撑并由信息层面系统地扩展至道德层面和法律制度层面。更多还原

【Abstract】 According to the statistics in CNNIC, there is a great increase in the number of Chinese netizens. By the end of 2007, the number of Chinese netizens has reached at 21 millions, with the annual increase rate of 53.3% and the second place in the world. The rapidly-developed Internet has penetrated into every aspect of China such as economy, politics, culture, and so on, leading to a positive and profound social reform. However, with the constantly high development of Chinese Internet, there are relevant problems involved in. The invisibility of network environment brought many problems such as Internet fraud, junk mail, and mal-intended software. In the trade of Internet, economic activities are in the multiple forms of uncertainty-such as the quality of information, the trade partner, the means of trade, the commercial credit and so on, leaving more crimes and fraud in the Internet trade. In a word, the usually-existing trust loss and the promotion of Internet trade trust in Internet environment, especially the Internet trade environment, are the urgent problems.The influential factors in the Internet trade trust loss are from different aspects, including the network itself and the external environment of Internet operation and existence-which are divided into three levels, morality, legal system and information. This dissertation is mainly based on the level of information, the viewpoint of initiatively solving information asymmetry, the research accomplishments of existing Internet trade trust and game theory. It establishes the signal transfer model of Internet trade, KMRW reputation model, incomplete information static game theory model and trust-agent model, makes several valuable conclusions, and proposed many policies and suggestions such as decreasing the information asymmetry in Internet environment, decreasing the risk and increasing Internet trust.The researches are divided into eight chapters, among which the parts between the second chapter and the eighth chapter are the main body.The first chapter is the introduction, mainly discussing the research background of the dissertation, defining the research boundaries, pointing out the purposes and significances of the research.The second chapter is about trust reference summery, separately stating the traditional trust theory and Internet trade trust theory, mainly introducing the influential factors of Internet trust-Internet main body, the relative party and the environment-and the research models of Internet trust-theoretical model, entity model and normative model.The third chapter analyzes the adverse selection problem in network environment based on game theory, points out that under the condition of information asymmetries no matter how high the acquaintance between the two parts of the trade, there is still the adverse selection in the two parts of one certain trade.The forth chapter discusses the trade warrant relevant issues in Internet trade by establishing Internet trade incomplete information static game theory model, makes the conclusion that when Internet trade requires more sellers participate the bid and the Internet trade efficiency can be increased and the Internet trust can be strengthened by seller decreasing the products’ fixed cost, operation cost and accumulated credit cost and buyer trying to group trade.The fifth chapter: KMRW model applied with Internet trade states that under certain circumstances, the two parties of the trade game will give up on optimizing short-term interest in order to optimize the long-term interest and will stick to the cooperation strategy; for maintaining the long-term cooperation, the seller tries the best to keep the reasonable profit other than the extreme high profit and in the condition of one party is honest and the other is cheating, the more the loss is, the more both parties are tending to cooperate for a long time. At last, accordingly it points out that maintaining the Internet brand has a great significance on keeping the Internet seller’s reputation and promoting Internet trust.The sixth chapter analyzes the condition and the equilibrium result of information signaling with the application of information signaling model, points out that decreasing the cost of good quality seller promoting credit level and increasing the cost of poor quality seller promoting credit level makes the credit level in Internet take the role of transferring product’s information, decreasing the information asymmetry and adverse selection in Internet trade; under these circumstances, the seller and the buyer have two departed equilibriums, and the payment function （ the revenue） are separately: ( P_H - C_G - C_GT, V_G - P_H )、(P_L-C_B-C_BT, V_B-P_L) ( among which P_H and P_L are the price offers on different qualities of products, P_H> P_L, C_G and C_B are the costs of products with different qualities, C_G > C_B , C_GT and C_BT are the accumulated credit costs of different Internet sellers, C_GT < C_BT , V_G and V_B are the effects on sellers posed by products with different qualities, V_G>V_B) ; it’s good to Internet trust by minishing cost gaps of Internet goods. At last, accordingly it proposes several policies and advises. The seventh chapter analyzes the relevant issues on bringing the third party in the Internet trade by establishing Internet trade trust-agent model, points out that in the condition of information asymmetry, the maximal effort level of the agent is less than the effort level of that under information symmetry, and the expected revenue of the seller is less than that under information symmetry; and the more the agent avoids the risk, the more the negative effect of the effort, the stronger the uncertainty of the output, the smaller the marginal revenue of agent working hard; the marginal cost of agent working hard only has the link with output sharing coefficientsβandχ, and is the increasing function of output sharing coefficient; through putting the measurable exogenous variable z in the contract, on the one hand, the leftover share of the agent can be increased, leaving increased motivation strength in contract and neglecting the influence outside, on the other hand, the risk taken by the agent can be decreased. At last, according the difference between the influential factors of the third party’s endeavor level and the risk preference, it proposes some relevant policies and suggestions.The eighth chapter is the summery and the research prospect, mainly summarizing the theoretical innovation and practical significance and pointing out the shortcomings of the research and the research direction in future.更多还原