【作者】 张志强；

【导师】 冯楠；

【作者基本信息】 天津大学 ， 管理科学与工程， 2016， 硕士

【摘要】 由于软件产品边际成本较低和网络外部性较高的特点,免费增值模式越来越受到软件厂商的欢迎。现有的关于免费增值模式的文献主要集中在正网络效应和侵蚀效应之间的均衡之上,认为只有当网络效应较强时,软件厂商可以通过提供一个免费版本来获取更多利润。然而,软件厂商采取免费策略时,还必须考虑由免费版软件用户引起的安全风险,相应地还应该选择一个补丁策略。本文研究了软件厂商面临的一种两阶段决策问题,包括免费增值策略和一个考虑了正网络效应和负安全外部性的补丁策略。本文采取了一种后向归纳的方式来解决这个问题,首先,建立模型并比较了三种可选的补丁策略:i)让所有软件用户免费打补丁（PS₁）;ii)向免费版软件用户打补丁收费（PS₂）;iii)仅向收费版软件用户提供补丁（PS₃）。通过这种方式,讨论并得到了在不同条件下的最优补丁策略。然后,通过与只提供收费版软件的情况进行比较,发现在中等或高的正网络效应下并且采取了最优补丁策略时,提供一个免费版本对软件厂商是有利可图的,并且软件厂商让免费版软件用户打补丁的动机也会随着安全风险的提高而增强。此外,提供一个免费版本会使社会福利有所提高,然而,只有在较强的正网络效应下,并且软件厂商采取了补丁策略1时,才能同时实现软件厂商的利润最优和社会福利最大化。本文的主要贡献在于,通过考虑软件网络中存在的安全风险问题,完善了免费策略的理论研究,同时为软件厂商更好的做出决策提供了指导。更多还原

【Abstract】 The freemium model has been increasingly embraced by software vendors,due to software’s characteristics of low marginal cost and high network externality.Existing literature on the freemium strategy mainly focuses on balancing the trade-off between positive network effect and the cannibalization effect,it’s profitable for the vendor to offer a freeware only if the network effect is strong.Nevertheless,a vendor has to take into account the negative security risks caused by the freeware users and choose a patching strategy accordingly.A two-stage decision problem faced with a software vendor is examined which involves a freemium strategy and a subsequent patching strategy considering both the positive network effect and the negative security externality effect.We adopt a backward induction fashion to solve the problem: First,we model and compare three alternative patching strategies:（i）patching for all users without charge（PS₁）;（ii）patching for freeware users with charge（PS₂）;（iii）patching for commercial users only（PS₃）.By doing so,we discuss the optimal patching strategy under different conditions.Then,we show that it is profitable for the software vendor to adopt a freemium model under a moderate or high positive network effect when the optimal patching strategy is adopted.With a higher negative security externality,the vendor has more incentive to allow the freeware users to patch.Besides,offering a freeware improves the social welfare,however,both the vendor’s optimal profit and the maximum social welfare can be achieved only if the vendor adopts the patching strategy PS₁ under a high positive network effect.The main contribution of this research is as follows,we make the theory research on freemium pricing model more perfect via taking the negative security externality into account,and it’s helpful for the software vendor when making the freemium decision.更多还原