【作者】 吉宏伟；

【导师】 李仕明；

【作者基本信息】 电子科技大学 ， 管理科学与工程， 2007， 博士

【摘要】 随着信息技术的高速发展，网络成为当今世界最为关注的问题之一。通过网络，个人、社会团体、企业及其他社会结构中的组织单元被有机联系起来，特别是在知识密集型产业里，企业可以通过网络互联实行资源优化整合，快速响应市场，并且实现成本共享以及更为有效地进行技术创新，这就是Puffert提出的所谓的“新经济”。而这种新经济最为显著的特征就是“网络外部性”，亦称“需求方规模经济”，即消费者消费某种网络产品的价值会随着消费该产品或与该产品相兼容的其它产品的消费者的数量的增加而增加。随着网络外部性理论研究的不断深入，国内外有关网络外部性研究的焦点越来越集中于企业产品间的兼容性决策问题。网络经济中，网络外部性和兼容性是最为显著和关键的特征，对企业的竞争战略有着深刻的影响。目前，学术界已达成共识：在具有网络外部性特征的产业中，产品兼容性不再是企业的纯技术问题，而是一个竞争战略问题，该战略的运用得当与否，直接关系到企业在市场竞争中的成败。兼容性竞争策略对企业具有正反两方面的效应：一方面，企业如果生产与市场上已有产品相兼容的产品，则由于网络外部性的正反馈效应提高了产品对消费者的价值，从而增强了消费者对企业产品的支付意愿；另一方面，生产兼容产品就意味着企业放弃了差异化优势，从而产生负面效应。因此，有的时候企业为了保持自己在市场中的垄断地位就会通过知识产权保护等手段来阻止竞争者获得兼容性，而对新进入企业来讲，他们更希望与在位企业进行兼容，从而享用在位企业已有的用户安装基础。不难看出，在具有网络外部性特征的产业中，企业的兼容性决策是最为关键的战略，而产品差异化战略又与之有着密不可分的关联，因此，系统研究存在网络外部性特征的产业中企业的产品差异化和兼容性策略不仅是对传统企业竞争理论的有益补充和对网络外部性理论的极大丰富，而且对现实网络经济中企业竞争策略的运用和政府管制部门制定相关的产业政策都具有十分重要的意义。本文在总结国内外相关研究的基础上，首先讨论了在具有网络外部性特征的产业中，垄断企业产品升级的兼容性决策问题；随后，在竞争的市场结构下，分别研究了在位企业和潜在进入企业产品差异化和兼容性决策问题；最后，基于以上的研究，对全文进行了总结，指出了本文存在的缺陷以及提出了未来研究的方向。本文以现代产业组织理论、博弈论及信息经济学等理论为研究工具，深入研究处于不同市场地位的企业产品差异化和兼容性决策问题：第一章对网络外部性理论的研究历史和现状进行了详细的综述，在此基础上进一步概述了在网络外部性条件下的企业产品差异化和兼容性研究现状，指出了现有对差异化和兼容性研究的不足，进而提出了本文要研究的问题。第二章着重研究垄断企业的产品升级的兼容性策略和福利效应分析。不同于现有有关在网络外部性条件下的纵向质量差异研究，这里建立了基于消费者对网络价值评价具有不同偏好的纵向差异模型，探讨了垄断企业在兼容或者不兼容策略下实施产品升级时的产品定价及社会福利效应。从第三章到第五章开始研究在竞争的市场结构下，在位企业和新进入企业在网络外部性条件下的产品差异化和兼容性策略。第三章研究了在产品具有横向差异的情况下，面对潜在进入企业的市场进入威胁，两个在位企业之间的兼容性决策。在位企业的产品兼容性决策会影响进入企业的市场进入决策，而潜在进入企业的进入决策又会影响在位企业之间的兼容性偏好，这种互动的影响会有怎样的结果呢?本章建立了一个三阶段横向差异化博弈模型，给出了这个问题的答案。第四章在第三章的基础上进一步研究潜在进入企业在产品具有横向差异化前提下，面对在位企业具有先天安装基础优势时的兼容性决策。通过产品之间的兼容度将消费者的转移成本内生化，得到了新进入企业兼容性决策的临界点，且该临界点与网络外部性强度负向相关。当新进入企业可获得的与在位企业产品相兼容的兼容度水平位于该临界点左侧区域时，采取拒绝与在位企业兼容的策略是最优的；反之，则采取兼容策略，从而新进入企业可以借助在位企业的安装基础迅速发展。第五章以第四章为基础，在产品具有纵向质量差异的情况下，研究了潜在进入企业的兼容性决策。对新进入企业来讲，转移成本和在位企业已有的用户安装基础是其进入市场的两大壁垒，所以新进入企业更加倾向兼容以此来降低消费者的转移成本和充分享用在位企业的网络优势；对在位企业来讲，虽然其具有先天的规模优势，但是较低的产品质量又迫使其也愿意采取兼容的策略，以免由于市场的惯性而遭淘汰。在竞争均衡中，发现网络外部性、转移成本和质量差异度是决定竞争双方市场势力的决定因素，由于转移成本是由兼容度内生的，所以最终的决定因素仍然是产品间的网络外部性、兼容度水平和质量差异度，由此可见，这三者的大小是决定进入企业和在位企业兼容性战略决策的关键因素。第六章对全文进行了总结，指出本文存在的不足以及在该领域值得继续深入研究的问题，为后续研究指出了有前景的方向。本文的创新点可以归结为以下几点：1．本文在研究框架上将网络外部性、产品差异化、兼容性决策统一到一个框架下，深入讨论了三者之间的相互关系对企业竞争战略的影响作用。已有研究往往将以上三者相互割裂开来进行研究，所有得出的结论具有很大的局限性。而本文将三者统一后，更符合网络经济的现实状况，得出的结论有更强的说服力，不仅丰富和发展了传统的企业竞争理论，而且对网络经济条件下的企业对各种竞争战略的运用和政府管制部门制定合理的竞争政策具有更实际的指导意义。2．本文将消费者对网络价值的非一致性评价引入到研究中，这极大修正了已有研究的前提假设：消费者对网络外部性具有一致偏好。这种假设显然与事实不能完全符合，在理论上会误导企业对市场规模的预期，从而有可能做出错误的决策。由于消费者个体之间的差异，即使位于同一网络中的用户对该网络的评价也不尽相同；同时，处于不同网络的用户对同一个网络却可能有相同的评价。在具有网络外部性特征的产业中，消费者对企业产品的预期因人而异，因此目前研究中普遍使用的可实现预期的方法就存在一定的弊端，这种可实现预期的方法直接影响到了现在已有的各种结论，对这一假设的矫正必定使这些结论偏离现在的轨道。3．本文研究了一个现有研究都忽略的问题，即在竞争的市场结构中，面对潜在进入企业的市场进入的威胁，多个在位企业之间的兼容性决策问题。本文对这一问题的研究在理论上使得现有理论更加完善，在实践中也更加具有指导意义。4．本文的研究不再局限于完全兼容和完全不兼容两种极端情形的探讨，而是将兼容性连续化，引入了具有连续统的兼容度参数。在现有研究中，企业的兼容性决策要么是完全兼容，要么是完全不兼容，这与现实情况有很大差距。在实际的网络经济中，网络产品之间多数都是部分兼容的，通过将兼容性用兼容度这个参数连续化，使得本文的研究与现实情况更加贴近。此外，由于兼容度这个参数的引入，本文将转移成本由其内生化，这也是现有研究所未涉及的。更多还原

【Abstract】 Nowadays networks are a central issue. They connect individuals, communities, firms and structure the workings of society as a whole. Especially, in knowledge-intensive industries firms can use networks to optimize resources, response markets rapidly, share costs and realize technique innovations more efficiently. This is so-called "new economy" by Puffert and its most significant feature is network externality. Network externality, also called scale of economy of demands, means that the individual benefit from, and consequently individual willingness to pay for, consumption of the good (service) is increasing in the number of people consuming the same good (service) or a compatible one.The literatures on network externalities are more and more abundant and now most authors focus on investigating the compatible decisions between firms. In network economy network externalities and compatibility are the most two significant characteristics and affect firms’ competitive strategies deeply. Meanwhile, the degree of compatibility between products is not a mere consequence of technological constraints, but is often a result of a firm’s strategic consideration. With the network externalities, compatibility strategies bring two opposite effects: firms are eager to produce compatible goods for which consumers have a higher valuation. Meanwhile, choosing to be compatible is renouncing some product differentiation. Hence, some incumbent firms deter potential competitors to achieve compatibility by using protection of patents. At the same time new entry firms always want to be compatible with incumbent for the sake of exploiting the installed base to gain some market shares. It goes without saying that compatibility strategy is the most crucial strategy among firms’ competitive strategies and product differentiation strategy has the closed relationship with it. Therefore, the deep investigation of the product differentiation and compatibility strategies of firms with the network externality not only are helpful for the traditional firm competitive theory and network externality theory, but also are meaningful for the firms to exploit all kinds of competitive strategies and government to make industry policies. Based on the previous research, the dissertation studies deeply the product differentiation and compatibility strategies of firms with the network externality under different market structure. Finally, we point out the future research fields. To these purpose, the theory of industrial organization, the game theory and information economics are employed.The main contents and results of the present paper are generalized as follows:First chapter is the introduction. Here we first introduce some related concepts, such as product differentiation, network externality and compatibility. After that, based on the previous research we point out some important problems, which will deeply investigate in present paper.In Chapter two we mainly study the strategies of compatibility of monopoly firm’s up-grade products and welfare effects. Different to traditional vertical product differentiation model, we construct a new model, where the consumers’ valuation about network externality will not be the same.From Chapter three to five we focus on consider the strategies of compatibility and product differentiation of incumbent and potential firms under the condition that the market structure is competitive.In Chapter three the strategies of compatibility of two incumbent firms, which are confronted with entry threaten, are studied with the horizontal differentiation. By employing a three stage game model we clearly give the answer.Based on the results obtained in Chapter three we in next Chapter study new entry firms’ compatibility decisions in a horizontal differentiation model with network externalities. A critical point of compatibility decisions, which increases as the strength degree of network externalities decreases, is obtained. When the degree of compatibility is less than the critical point, the entry firm will not take compatibility decisions. Otherwise, the entry firm will chose compatibility decisions to enjoy the installed base of incumbent firm.On the assumption that the products have vertical differentiation the strategies of compatibility of potential entry firm are considered. For new entry firm the switching-cost and installed base of incumbent are the two market entry barriers. Thus, new entry firm would like to be compatibility with incumbent firm to use the competitor’s network and decrease the consumers’ switching-cost. However, for incumbent firm although he has the advantages of scale, he also would like to make compatibility with new entry firm because of its lower product quality in order not to be cancelled by market. In competitive equilibrium we find that network externality, switching-cost and the differences between products are the key factors to decide market power. In view of the reason that the switching-cost is decided by the degree of compatibility, the most key factors are network externality, the degree of compatibility and the differences between products.In last section we put forward the future research fields.The key innovations include:1 .The framework of the paper is very different to previous related literatures. Here we make the network externality, product differentiation and compatibility as a whole and under the same framework we study deeply the relationships among above three factors. Hence, our mathematical models and results are closed to real life.2.Many of results in the network externality research field obtained by different authors in the word are based on a special assumption, that is , the valuation of all consumers for network value are the same. Obviously, under this assumption the related results can not explain real life clearly. In present paper we rectify the assumption.3.Most of studies are concentrating on the product differentiation and compatibility strategies of the potential entry firms in stead of incumbent firms, especially for more than two incumbent firms. But this problem is very important. How do these incumbent firms choose product differentiation and compatibility strategies? The present paper studies the problem and gives some results.4.The degree of compatibility between products in our study is a continuum in stead of two extreme situations, which are full compatibility and full incompatibility. Furthermore, switching-cost is decided endogenously by degree of compatibility. Then we obtain the compatible critical point of new entry firm.更多还原