This study was carried out to investigate the effect of side vent heights on temperature and relative humidity inside and outside the single-span plastic greenhouse (W: 7 m, L: 40 m H: 3.9 m) during natural ventilation. Four different heights (120, 100, 80, 60 cm) of the side vent were used as an experimental condition. Variations of temperature and relative humidity inside and outside the greenhouse and the differences between heights were compared by using one-way ANOVA. In the daytime, the difference in temperature between inside and outside the greenhouse was dropped from 14.0°C to 7.1°C as the side vent height increased. The temperature difference in the nighttime was less than 0.2°C regardless of the height. One-way ANOVA on the temperature difference between heights presented that the statistical significance was founded between all of the combinations of height in the daytime. The difference in relative humidity between inside and outside the greenhouse was grown from –13.8% to – 22.2% with a decrease in the side vent height. The humidity difference in the nighttime was less than 1% regardless of the height. One-way ANOVA on the humidity difference revealed that most of the side vent heights showed significance in the daytime but between 100 and 80 cm was not significant. It seemed because the external air became cooler during the experiment with a height of 80 cm. Conclusively, this study empirically demonstrated that the higher side vents resulted in the decrease of differences in temperature and relative humidity between inside and outside the greenhouse, and also the effect of side vent height was statistically significant. This study may be helpful for deciding the height of the side vent effective for controlling temperature and relative humidity in a single-span greenhouse during natural ventilation.

관리도를 사용하여 공정평균, 공정산포 등 여러 가지 공정모수를 관리할 수 있다. 그러나 공정모수의 미세 변동을 효과적으로 관리할 수 있는 기법체계는 아직 미완이다. 식스시그마 공정관리 등 정밀공정관리를 위해서는 미세 공정평균과 공정산포관리가 전제되어야한다. 특히 높은 수준의 공정능력을 유지하기위해서는 공정산포관리가 선결과제이다. 본 본문에서는 공정평균과 공정불량률, 공정산포의 미세변동을 효과적으로 관리할 수 있는 기술체계의 연구동향을 분석하고 미세공정산포관리를 위한 대안을 제시하고자 한다.