Network externalities are essentially dynamic in that the value consumers feel about a product is affected by the size of the existing customer base that uses that product. However, existing studies on network externalities analyzed the effects of network externalities in a static way, not dynamic. In this study, unlike previous studies, the impact of network externalities on price competition in a vertically differentiated market is dynamically analyzed. To this end, a two-period duopoly game model was used to reflect the dynamic aspects of network externalities. Based on the game model, the Nash equilibria for price, sales volume, and revenue were derived and numerically analyzed. The results can be summarized as follows. First, if high-end product has strong market power, the high-end product vendor takes almost all benefits of the network externality. Second, when high-end product has strong market power, the low-end product will take over most of the initial sales volume increase. Third, when market power of high-end product is not strong, it can be seen that the effects of network externalities on the high and low-end products are generally proportional to the difference in quality. Lastly, if there exists a strong network externality, it is shown that the presence of low-end product can be more profitable for high-end product vendor. In other words, high-end product vendor has incentive to disclose some technologies for the market entrance of low-end product, even if it has exclusive rights to the technologies. In that case, however, it is shown that the difference in quality should be maintained significantly.

Quality function deployment (QFD) is a useful method in product design and development to maximize customer satisfaction. In the QFD, the technical attributes (TAs) affecting the product performance are identified, and product performance is improved to optimize customer requirements (CRs). For product development, determining the optimal levels of TAs is crucial during QFD optimization. Many optimization methods have been proposed to obtain the optimal levels of TAs in QFD. In these studies, the levels of TAs are assumed to be continuous while they are often taken as discrete in real world application. Another assumption in QFD optimization is that the requirements of the heterogeneous customers can be generalized and hence only one house of quality (HoQ) is used to connect with CRs. However, customers often have various requirements and preferences on a product. Therefore, a product market can be partitioned into several market segments, each of which contains a number of customers with homogeneous preferences. To overcome these problems, this paper proposes an optimization approach to find the optimal set of TAs under multi-segment market. Dynamic Programming (DP) methodology is developed to maximize the overall customer satisfaction for the market considering the weights of importance of different segments. Finally, a case study is provided for illustrating the proposed optimization approach.

1990년대 중반 인터넷의 상용화가 활발해지면 서 인터넷을 기반으로 하는 다양한 사업모델들이 개발되고, 기업의 경제활동의 상당부분이 인터넷 을 기반으로 이루어지는 추세가 더욱 심화되고 있 는 상황이다. 그런데 이 같은 인터넷 기반 사업자들 에게 경쟁법을 적용함에 있어서 흥미로운 논의들 이 이루어지고 있다. 경쟁법적 분석의 출발점인 시 장획정과 관련하여, 가격에 근거한 대체가능성이 라는 전통적인 경쟁법적 전제가 과연 인터넷 기반 사업에도 그대로 적용될 수 있는지, 부당한 공동행 위의 경우에 인터넷 기반 사업의 특징으로 인하여 경쟁제한적인 합의에 대한 평가가 달라질 수 있는 지, 시장지배적 지위의 남용에 있어서 시장지배력 을 인정하는 근거나 남용행위의 부당성을 판단함 에 있어서 인터넷 기반 사업의 특징들이 어떻게 평가될 것인지, 기업결합에 있어서도 인터넷 기반 사 업자들 간의 결합에 대한 관련 시장에서의 경쟁제 한성을 판단하는 기준은 전통적인 사업자들 간의 결합의 경우와 어떠한 차이점이 있을 수 있는지 등 에 대한 많은 논의들이 이루어지고 있다. 우리나라 의 공정거래위원회도 인터넷 기반 사업자들에 대 하여 공정거래법상의 다양한 규제를 한 사례들이 축적되고, 이에 대한 법원의 판단을 받은 사례들도 증가하고 있다. 온라인 음악서비스 사업자들의 부 당한 공동행위에 대한 사건, 오픈마켓 사업자의 시 장지배적 지위 남용사건, 오픈마켓 사업자들의 기 업결합 사건 등에서 이러한 인터넷 기반 사업에 대 한 특징들이 고려되었다. 나아가 공정거래위원회 는 인터넷 기반 사업이 소비자에게 미치는 파급력 을 고려하여 전자상거래법상 금지되는 기만적인 소비자 유인행위를 판단함에 있어서는 매우 엄격 한 의무를 인터넷 기반 사업자들에게 부과하였다. 이는 인터넷 기반 사업에서의 소비자보호에 대하 여는 매우 엄정한 법집행을 하겠다는 의지가 반영 된 것으로 보인다.

The paper examines the dynamic relationship of domestic credit and stock market liquidity on the economic growth of the Philippines from 1995 to 2018 applying the autoregressive distributed lag (ARDL) bounds testing approach to cointegration, together with Granger causality test based on vector error correction model (VECM). The ARDL model indicated a long-run relationship of domestic credit and stock market liquidity on GDP growth. When the GDP per capita is the dependent variable there is weak cointegration. Also, the Johansen cointegration test confirmed the existence of long-run relationship of domestic credit and stock market liquidity both on GDP growth and GDP per capita. The VECM concludes a long-run causality running from domestic credit and stock market liquidity to GDP growth. At levels, domestic credit has significant short-run causal relationship with GDP growth. As for stock market liquidity at first lag, has significant short-run causal relationship with GDP growth. With regards to VECM for GDP per capita, domestic credit and stock market liquidity indicates no significant dynamic adjustment to a new equilibrium if a disturbance occurs in the whole system. At levels, the results indicated the presence of short-run causality from stock market liquidity and GDP per capita. The CUSUMSQ plot complements the findings of the CUSUM plot that the estimated models for GDP growth and GDP per capita were stable.