• 한국ITS학회 논문지
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• 제11권6호
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• pp.81-88
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• 2012

다중 입출력(MIMO : Multiple-Input Multiple-Output) 시스템은 공간 다이버시티 이득과 공간 다중화 이득을 얻을 수 있게 한다. 본 논문에서는 MIMO 시스템에서 데이터 정보와 안테나 선택 기법을 이용한 공간 부호화 기법을 제안한다. 이 기법은 부호화 이득과 동시에 공간 다이버시티 이득을 얻을 수 있게 한다. BPSK(Binary Phase-Shift Keying) 변조 방식을 사용한 MIMO 시스템에서 BER 성능을 분석하고, 데이터의 편재율에 따라 달라지는 공간 다이버시티 이득을 실험을 통하여 비교하였다.

• 설비공학논문집
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• 제16권3호
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• pp.230-240
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• 2004

An experimental investigation was conducted to study two-phase flow distribution in a T-type distributor of slit fin-and-tube heat exchanger using R22. A comparison was made between the predictions by previously proposed tube-by-tube method and experimental data for the heat transfer rate of evaporator. Experiments were carried out under the conditions of saturation temperature of 5$^{\circ}C$ and mass flow rate varying from 0.6 to 1.2kg/min. The inlet air has dry bulb temperature of 27$^{\circ}C$, relative humidity of 50% and air velocity varying from 0.63 to 1.71㎧. Experiment show that air velocity increased by 85.2% is need for T-type distributor with four outlet branches than that of two outlet branches under the superheat of 5$^{\circ}C$, which resulted in air-side pressure drop increase of 130% for T-type distributor with four outlet branches as compared to two outlet branches.

• International Journal of Air-Conditioning and Refrigeration
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• 제13권2호
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• pp.107-118
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• 2005

An experimental investigation was made to study two-phase flow distribution in a T-type distributor of slit fin-and-tube heat exchanger using R-22. Experiments were carried out under the conditions of saturation temperature of $5^{\circ}C$ and mass flow rate varying from 0.6 to 1.2kg/min. The inlet air has dry bulb temperature of $27^{\circ}C$, relative humidity of 50% and air velocity varying from 0.63 to 1.71m/s. A comparison was made between the predictions from the previously proposed tube-by-tube method and the present experimental data for the heat transfer rate of evaporator. Results show that $82.5\%$ increase of air velocity is needed for T-type distributor with four outlet branches than that of two outlet branches under the superheat of $5^{\circ}C$, which resulted in increasing of air-side pressure drop of $130\%$ for the former as compared to the latter.

• Journal of Preventive Medicine and Public Health
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• 제34권3호
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• pp.219-227
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• 2001

Objectives : To understand the current status of the opening, closing and relocation of primary medical institutes in Korea and identify the underlying decision factors. Methods : Sources of analyzed data included the medical institutional master file at the National Health Insurance Corporation(1998, 2000) and Regional Statistic Annual Bulletins. To investigate changes including the opening, closing and relocation, a total of primary medicalinstitutions(16,757 in 1998, 19,267 in 2000) were analysed. Results : Between 1998 and 2000, there was a 15.0%(2,510) increase in the number of primary medical institutions and the rate of increase in the rural area was higher than the urban area, and higher for specialty clinics than primary practice. However, these findings did not suggestany improvement in the maldistribution of primary medical institutions. During the time period studied, newly opened and closed primary medical institutions numbered 4,085 and 1,573, respectively. Additionally, institutions thatrelocated numbered 2,729, or 16.3% of all primary medical institutions in operation in 1998. These openings and closings were more frequent among young doctors. As a result of our analysis on the underlying regional factors forrelocation, the factors that were statistically significant were local per capita tax burden and the number of schools per ten thousand persons. !n, the case of institutional factors, movements were significantly associated with gender and the location of primary medical institutions. Conclusions : In order to establish effective long-term intervention for primary medical institutions, further study and monitoring of primary medical institutions and the identification of factors influencing opening location and relocation is necessary.