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이영수,조주현 한국산업조직학회 2003 産業組織硏究 Vol.11 No.2
본 연구는 기술개발 속도가 현저하게 이루어지고 있는 컴퓨터 및 주변기기(모니터, 프린터)를 대상으로 품질조정 가격지수를 산정하였다. 또한, 이러한 품질조정 가격지수가 생산자물가지수를 포함하여 ICT부문의 생산자물가지수에 미치는 효과를 살펴보았다. 품질조정 가격지수를 구하기 위해 헤도닉방법을 이용하였으며, 추정방법으로는 더미변수를 이용하여 추정하였다. 실증분석 결과를 요약하면 다음과 같다. 첫째, 컴퓨터 및 주변기기의 품질조정 가격하락 효과 분석에서 컴퓨터 본체의 가격지수는 1990년-2002년 동안 연평균 26.4%p 추가적으로 하락하는 것으로 나타났다. 모니터와 프린터의 경우 각각 연평균 15%p, 11.5%p의 추가적인 가격하락 효과가 있는 것으로 나타났다. 둘째, 컴퓨터 및 주변기기의 물가지수는 품질향상으로 1991-2002년 동안 연평균 11.54%p의 추가적인 가격하락을 보였다. 이러한 컴퓨터 본체, 모니터 및 프린터의 품질개선 효과로 사무회계용 기기의 물가지수는 추가적으로 연평균 10.83%p 하락했으며, ICT부문의 물가지수 역시 연평균 1.542%p 추가적인 하락이 나타났다. 또한 이러한 품질개선에 따른 추가적인 물가하락은 생산자물가지수에도 영향을 주어 1991년-2002년 기간동안 연평균 1.495%p의 추가적인 물가하락을 보였다. 셋째 본 연구와 이영수 외(2002)의 연구를 비교하여 볼 때 컴퓨터 본체의 품질조정으로 인한 가격하락 효과 추이는 비슷하게 나타나고 있어 본 연구의 결과가 안정적이고 강건한(robust)한 추정결과임을 알 수 있었다. In this paper, we attempt to calculate a quality-adjusted price indexes for the personal computer and peripheral devices(monitor, printer) that have experienced rapid technological and market developments. Moreover we analyze the PPI of ICT including the quality-adjusted price index. To calculate a quality-adjusted price index we utilize the framework of the hedonic approach and dummy variable estimation method. The conclusions which can be drawn from our empirical study are these: 1) personal computer, monitor, printer price indexes decline additionally at about 26.4%p, 15%p, 11.5%p respectively over the 1990∼2002 time period 2) price indexes in office accounting machinery and ICT decline additionally 10.83%p, 11.54%p respectively 3) PPI declines additionally 1.542%p per year considering the quality changes 4) comparing the previous work we know that our empirical results are stable and robust.
이영수,한성욱,김윤년,남창욱,김형섭,김기식,Robert W. Rho 대한심장학회 2008 Korean Circulation Journal Vol.38 No.11
Background and Objectives: Long-term right ventricular (RV) apex pacing has been associated with left ventricular (LV) systolic dysfunction. However, pacing in the RV outflow tract (RVOT) is associated with a narrower QRS duration and may have a more normal LV activation in comparison to RV apical (RVA) pacing. We hypothesized that RVOT pacing is associated with less mechanical dyssynchrony compared to RVA pacing and that it also more closely resembles mechanical activation in normal controls with a narrow QRS. Subjects and Methods: We studied 9 patients with RV pacing, 9 with left bundle branch block (LBBB), and 15 normal controls with a narrow QRS. In the RV pacing group, we paced from the RVA and RVOT. At the end of each pacing train, we obtained echocardiographic images in the apical 4- and 2-chamber views and obtained the following parameters: the compression/expansion crossover point (CEP) for myocardial strain and the time from QRS onset to the CEP in the strain image. The degree of dyssynchrony was evaluated using the dispersion and standard deviation of CEP times in 12 segments of the LV. Results: Significant dyssynchrony was observed in the RVOT pacing group compared to the group with normal QRS. No significant difference was observed in LV mechanical dyssynchrony among the RVOT pacing, RVA pacing, and LBBB groups. Conclusion: RVOT pacing is associated with significant LV dyssynchrony. Although the RVOT has been recommended as an alternative site for pacing, this approach may have adverse effects on long-term LV function. Background and Objectives: Long-term right ventricular (RV) apex pacing has been associated with left ventricular (LV) systolic dysfunction. However, pacing in the RV outflow tract (RVOT) is associated with a narrower QRS duration and may have a more normal LV activation in comparison to RV apical (RVA) pacing. We hypothesized that RVOT pacing is associated with less mechanical dyssynchrony compared to RVA pacing and that it also more closely resembles mechanical activation in normal controls with a narrow QRS. Subjects and Methods: We studied 9 patients with RV pacing, 9 with left bundle branch block (LBBB), and 15 normal controls with a narrow QRS. In the RV pacing group, we paced from the RVA and RVOT. At the end of each pacing train, we obtained echocardiographic images in the apical 4- and 2-chamber views and obtained the following parameters: the compression/expansion crossover point (CEP) for myocardial strain and the time from QRS onset to the CEP in the strain image. The degree of dyssynchrony was evaluated using the dispersion and standard deviation of CEP times in 12 segments of the LV. Results: Significant dyssynchrony was observed in the RVOT pacing group compared to the group with normal QRS. No significant difference was observed in LV mechanical dyssynchrony among the RVOT pacing, RVA pacing, and LBBB groups. Conclusion: RVOT pacing is associated with significant LV dyssynchrony. Although the RVOT has been recommended as an alternative site for pacing, this approach may have adverse effects on long-term LV function.