本文於存在高和低品質兩家製造商之垂直產品差異化的模型下，加入網路外部性。探討製造商採取直接通路和間接通路的兩種情況銷售，產品品質與其網絡大小有何不同。主要結果顯示，無論兩家製造商均採取直接通路或是間接通路的方式銷售，高品質產品之品質均會因網路外部性的力量提升而提高，低品質產品之品質則均會降低，兩產品間的品質差異進而提高；而高品質產品之網絡大小會增加，低品質產品之網絡大小會減少。此外，相較於直接通路，兩家製造商均採取間接通路的方式銷售，高和低品質產品之品質均會降低，以及兩產品間的品質差異降低；而高和低品質產品之網絡大小均會減少。

This paper studies the quality decisions of two manufacturers and the network sizes of the high- and low-quality products under direct and indirect channels, respectively. The main results show that, in both cases of direct and indirect selling, if the extent of network externalities increases, the quality of the high-quality product increases while that of the low-quality product decreases, resulting in a greater vertical product differentiation. Moreover, the network size of high-quality product expands, while that of low-quality product shrinks. However, compared to the results of direct selling, when both manufacturers adopt an indirect channel, the quality of both high- and low-quality products are lower, and the vertical product differentiation is smaller. Also, the network sizes of both high- and low-quality products are reduced.

論文審定書 i
摘要 ii
Abstract iii
目錄 iv
圖次 v
第一章 前言 1
第二章 文獻回顧 3
第三章 模型 5
3.1 直接通路（direct channel, D） 8
3.2 間接通路（indirect channel, I） 11
3.3 直接通路與間接通路之比較 14
第四章 結論 19
參考文獻 21

中文部分
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英文部分
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