우리나라는 54년 전부터 고속국도를 건설하기 시작하였다. 그러나 고속국도의 주요 시설물들 자체에 대한 연구는 찾아볼 수 없었다. 그래서 분기점과 휴게소에 이어 나들목의 명칭 특성을 분석하였다. 2020년 말 현재 500개 나들목에 대한 분석 결과는 다음과 같다. 나들목 명칭의 어종은 95.8%가 한자어였고, 평균 음절수는 2.60음절로 상당히 짧았으며, 대체로 지수분포를 보였다. 명명 유연성 측면에서는 행정구역명 관련 나들목 명칭이 65.0%로 가장 많았고, 결합지명이 28.2%로 다음을 차지하였다. 이들 명칭이 다수를 차지한 것은 한국도로공사의 ｢시설물 명칭 부여 기준｣ 때문이라고 판단된다

PURPOSES: The objective of this study is to analyze the effect of superelevation on the existing local freeway ramps where occurrence of traffic incidents are concentrated in order to improve the safety of ramp curves. Using a superelevation slope test conducted on Cheong-ju interchange as a case study, operating speed and lateral friction coefficients are measured, and the safety before and after increasing the superelevation is analyzed. METHODS: First, the actual operating speed of freeway ramps is measured for analysis and the 85th-percentile speed is calculated. This is followed by a measurement change in the lateral friction coefficient because of an increase in superelevation slope from 6% to 10%. Based on the change in lateral friction coefficient, an evaluation of the safety of driving mechanics is carried out and suggestions for the most appropriate superelevation slopes are presented. RESULTS: The operating speed (V85) of the loop ramp increases by up to 5.6 km/h after increasing the superelevation slope, and the operating speed (V85) of reverse ramp curve increases by up to 6.1 km/h. However, the standard deviation of the speed between each section has decreased, making it easier to drive smoothly. Although some sections of the loop ramp show poor safety due to the difference between actual and design friction coefficients in the safety evaluation before the increase of superelevation slope, the lateral force decreases after the increase of superelevation slope, improving the safety of the road. CONCLUSIONS : Currently, Korea’s freeway ramps pose a safety risk to vehicles traveling at speeds higher than the design speed. To improve the safety of freeway ramps, analysis on the effect of increase in superelevation slope found that the lateral friction coefficient decreases, which in turn improves the safety of freeway ramps.

Fluid motion within the internal combustion engine cylinder plays a major role in controlling the fuel/air mixing and combustion processes in spark-ignition engines, and the combustion processes in compressionignition engines. In-cylinder flow is quite unstable and varies from one cycle to another. Various methods of in-cylinder flow measurement and fuel/air mixing characterization have been developed during the past few decades. In particular, laser based flow diagnostic techniques have been utilized for this purpose. This study will focus on the quantification of spark-ignition engine in-cylinder flow using the laser based flow diagnostic techniques. The measurement methods, including high speed flow visualization and laser Doppler velocimetry (LDV), will be discussed.

We present an optical UBVRI photometric analysis of the poorly studied open star cluster IC 2156 using Sloan Digital Sky Survey data in order to estimate its astrophysical properties. We compare these with results from our previous studies that relied on the 2MASS JHK near-infrared photometry. The stellar density distributions and color-magnitude diagrams of the cluster are used to determine its geometrical structure, real radius, core and tidal radii, and its distance from the Sun, the Galactic plane, and the Galactic center. We also estimate, the age, color excesses, reddening-free distance modulus, membership, total mass, luminosity function, mass function, and relaxation time of the cluster.