• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.47-52
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• 2003

117 undergraduate ophthalmic optics students volunteered to participate in this study. They ranged in age from 19 to 26 years. Subject, had best corrected visual acuity of at least 1.0 in both eyes, no strabismus, no amblyopia, and no history of ocular surgery. 37 subjects are esphoria and 25 subjects are $3{\Delta}$ and less, and the rest of 12 subjects show more $4{\Delta}$. Average phoria amount is $2.96{\Delta}$ at far distance and $1.08{\Delta}$ at near distance, respectively. The variation of phoria amount in far and near distance, unchanging subjects are 3, 8 subjects are increase esophoria amount, and 26 subjects are phoria amount decreasing or appear exophoria. The reason of esophoria amount is decreasing in near distance, and the results are convergence burden decreases. At positive relative convergence, the expected value in far distance, blurred point is 7, break point is 16, and recovery point is 12. And negative relative convergence, break point is 7 and recovery point is 13, respectively. Moreover, at positive relative convergence, the expected value in near distance is blurred point is 8, break point is 7 and recovery point is 22. And negative relative convergence, blurred point is 2, break point is 8 and recovery point is 12, respectively.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.13-21
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• 2023

In this study, the coastal airborne chlorides were investigated in the Incheon Port, South Korea. Monthly measurements of coastal airborne chlorides were taken for a total of 2 years from September 2021 to August 2023 at 15 locations in North, South, and New Port. We analyzed the distribution characteristics of airborne chloride based on port facilities and measurement environments, as well as the reduction characteristics of the airborne chloride with respect to coastal distance. As a result, the monthly distribution range of the airborne chloride in the North, South, and New Port varied similarly, ranging from 0.4 to 3.3 mdd. Due to the influence of seasonal winds considering the direction of the coastline, both the North Port and South Port had higher the airborne chloride in winter, while the New Port had higher content in summer. The airborne chlorides were higher at locations inside an inland sea compared to those outside an inland sea. This is because the wind coming from the sea passed through the inland sea. Even in the same region with identical coastal distances, there were variations in airborne chloride levels depending on the height above the ground. In tidal zone, the monthly airborne chlorides were significantly higher in the lower part than in the upper part. The rate of decrease equation of airborne chlorides for each port based on the distance from the coastline was derived, and the results showed that as the distance from the coastline increased, the rate of decrease in airborne chlorides was the highest for New Port and the lowest for South Port.

• Journal of Navigation and Port Research
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• v.43 no.6
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• pp.413-419
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• 2019

Traffic routes typically have heavy traffic. Especially, the entrance of the route has a high risk of accidents occurring because of ships entering and exiting the port. However, almost of studies have focused on the distribution of traffic on the route. Thus, studies on the distribution between ships for passing through the route are insufficient. The purpose of this study was to analysis the traffic in the Busan north port No.1 route for one week. Based on present traffic conditions, one gate line was settled on the route with an analysis of traffic conditions. Based on the analysis data, each optimal time probability distribution between ships was divided into inbound/outbound and traffic volume. An analysis of the optimal probability distribution, was applied to 31 probability distributions divided into bounded, unbounded, non-negative, and advanced probability distribution. The KS test was applied for identifying three major optimal time probability distributions. According to the KS test results, the Wakeby distribution is the best optimal time probability distribution on the designated route. Although the optimal time probability distribution for other transportation studies such as on vehicles on highways is a non-negative probability distribution, this distribution is an advanced probability distribution. Thus, the application of major probability distribution for using other transportation studies is not applicable to this study Additionally, the distance between ships in actual traffic surveys and the distance estimated by the optimal probability distribution were compared. As a result of the comparison, those distances were fairly similar. However, this study was conducted in only one major port. Thus, it is necessary to investigate the time between ships and calculate a traffic volume on varying routes in future studies.

• Proceedings of the KOR-KST Conference
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• 2000.02a
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• pp.3-22
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• 2000

이용자의 경로선택 형태를 모사하는 통행배정모형 결과의 정확도는 교통계획에 상당한 영향을 미친다. 이용자의 경로선택 결정과정에서 가장 중요한 판단기준은 통행시간과 통행요금이다. 그런데 통행요금은 이용자의 경로거리에 따라 다양한 방식으로 부과되므로, 링크를 분석단위로 하는 기존의 통행배정모형은 현실적인 통행요금 반영이 힘들었고 또한 수요예측 결과를 이용한 다양한 분석에서 제약을 받아 왔다. 본 연구는 이러한 배경에서 경로교통량을 도출할 수 있는 경로기반 통행배정모형을 구축하였고, 또한 경로거리에 따라 결정되는 현실적인 통행요금을 반영할 수 있는 알고리즘을 개발하였다. 경로기반 배정모형에서는 GP(Gradient Projection) 알고리즘을 이용하였고, 계산상의 효율성 제고를 위해 K-최단경로 알고리즘 중 MPS(Minimal Path Search) 알고리즘을 이용하였다. 개발된 배정 모형은 현실적인 통행요금을 반영할 수 있으므로 통행배정 결과의 정밀도를 향상시켰을 뿐만 아니라 기존 배정모형에 비해 최적해로의 수렴속도도 개선되는 것으로 나타났다. 본 논문의 배정모형은 경로교통량이 도출되고 통행요금을 반영할 수 있으므로, 통행요금과 통행 거리 관계에 따른 목적함수의 규명과 그에 따른 효과척도를 계량화할 수 있다. 따라서 본 모형은 통행배정에서 실재상황을 보다 현실여건에 맞도록 규명할 수 있고, 기존의 제한적인 효과분석의 문제점을 해결할 수 있으므로 그 활용범위가 넓다. 또한 본 논문은 개발된 배정모형의 적용사례로서 고속도로 수요관리 요금체계 개선방안을 제시하였다. 기존의 고속도로 통행요금 산정 방법은 이론적 근거가 미약했던 반면, 본 논문에서 개발된 배정모형과 고속도로 수요관리 요금체계 개선방안은 고속도로 통행료 결정에 대한 과학적이고 합리적인 분석방법을 제공하였다.한 민감도 분석을 실시한 결과 대안1의 경우 교통량의 변화 및 화물통행의 시간가치의 증가시 사회적 편익이 오히려 감소하였고, 대안2와 3의 경우 사회적 편익이 증가하는 것을 알 수 있었다. 이는 경부고속도로의 화물차량의 구성비에 따라 대안 1의 경우 오히려 화물차의 통행시간이 증가함에 그 원인이 있다 할 것이다. 이상과 같은 결론을 통하여 경부고속도로상의 화물전용차선의 설치시는 수답렬 교통량의 구성비와 구간 평균교통량에 의하여 그 효과가 다르게 나타남을 알 수 있었다. 따라서 물류비용 절감차원에서의 화물전용차선의 설치는 본 연구에서 나타낸 방법과 같이 수단간의 경제적 편익을 고려한 구간별 시간대별 효과분석을 통하여 정책의 시행여부가 결정되어야 할 것이다. 한편, 화물전용차선의 설치로 인한 물류비용의 절감을 보다 효과적으로 달성하기 위해서는 종합류류 전산망의 시급한 구축과 함께 화물차의 적재율을 높이고 공차율을 낮출 수 있는 운송체계의 수립이 필요한 것으로 판단된다. 그라나 이러한 화물전용차선의 효과는 단기적인 치유책일 수밖에 없기 때문에 물류유통 시설의 확충을 위한 사회간접자본의 구축을 서둘러 시행하여야 할 것이다.으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한 시추공 내 물리검층과 정압주입시험에서도 확인된다.. It was resulted from increase of weight of single cocoon. "Manta"2.5ppm produced 22.2kg of co

• Journal of Korean Society of Forest Science
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• v.84 no.4
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• pp.409-414
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• 1995

This study was carried out for the analysis and comparison about the noise diminution effects by the height, width and density of Euonymus japonica wall, the distance of sound source, the distance of sound receiver, the height of sound source, and the height of sound receiver. The results obtained were summarized as follows; 1. After the establishment of tree wall, the volume of noise diminution measured 6.8dB and the effects of noise diminution measured heigher than before by 10.6% and t-value was significant at the 1% level 2. In simple correlation between the effects of noise diminution and variables, the density of tree wall was found as the most significant factor, and the last were found in the order of the distance of sound receiver, the width of tree wall, and the distance of sound source. 3. In partial correlation coefficients the effects of noise diminution and variables, the density of tree wall (r=-0.959) was found as the most significant factor, and the last were found in order of the distance of sound receiver (r=-0.906) and the width of tree wall (r=-0.753). 4. The estimated equation to measure the effects of noise diminution according to variables (the height of tree wall, the width of tree wall, the density of tree wall, the distance of sound source, the distance of sound receiver, the height of sound source, and the height of sound receiver) was $Y=69.520-1.672X_1-1.656X_2-0.066X_3-0.248X_4-3.134X_5-0.222X_6-0.343X_7$, and the coefficient of determination of this estimated equation was highly found as 0.950. 5. In semi-partial correlation coefficient the effects of noise diminution were found in the order of the density of tree wall, the distance of sound receiver, the width of tree wall, and the height of tree wall from the highest to the lowest. Therefore, it was considered that the density of tree wall, the distance of sound receiver, the width of tree wall and the distance of sound source should be controlled effectively to increase the effects of noise diminution by Euonymus japonica wall.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.7-16
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• 2004

The homogeneous road section is defined as one consisted of similar traffic characteristics focused on demand and supply. The criteria, in the aspect of demand, are the diverging rate and the ratio of green time to cycle time at signalized intersection, and distance between the signalized intersections. The criteria, in that or supply, are the traffic patterns such as traffic volume and its speed. In this study, the effective method to generate valuable data, pointing out the problems of removal method of obscure data, is proposed using data collected from Gonjiam IC to Jangji IC on the national highway No.3. Travel times are collected with licence matching method and traffic volume and speed are collected from detectors. Futhermore, the method of selecting homogeneous road section is proposed considering demand and supply aspect simultaneously. This method using outlier filtering algorithm can be applied to generate the travel time forecasting model and to revise the obscured of missing data transmitting from detectors. The point and link data collected at the same time on the rational highway can be used as a basis predicting the travel time and revising the obscured data in the future.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.1
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• pp.41-46
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• 2011

Reliable information on the surface solar radiation is indispensable for rebuilding food production system in the famine plagued North Korea. However, transfer of the related modeling technology of South Korea is not possible simply because raw data such as solar radiation or sunshine duration are not available. The objective of this study is restoring solar radiation data at 27 synoptic stations in North Korea by using satellite remote sensing data. We derived relationships between MODIS radiation estimates and the observed solar radiation at 18 locations in South Korea. The relationships were used to adjust the MODIS based radiation data and to restore solar radiation data at those pixels corresponding to the 27 North Korean synoptic stations. Inverse distance weighted averaging of the restored solar radiation data resulted in gridded surfaces of monthly solar radiation for 4 decadal periods (1983-1990, 1991-2000 and 2001-2010), respectively. For a direct application of these products, we produced solar irradiance estimates for each sub-grid cell with a 30 m spacing based on a sun-slope geometry. These products are expected to assist planning of the North Korean agriculture and, if combined with the already prepared South Korean data, can be used for climate change impact assessment across the whole Peninsula.

• Journal of the Korean Geotechnical Society
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• v.32 no.11
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• pp.83-96
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• 2016

The surface settlement of the back ground of a braced wall due to the ground excavation has the great influence on the safety of the surrounding area. But it is not easy to predict the settlement of the surrounding area due to proud excavation. Estimation of the settlement of the surface ground induced by the deformation of the braced wall is performed by FEM and empirical method (Peck, Clough etc). In this research, surface settlement of the back ground braced wall depending on the joint dips in rocks during excavating the composit ground was measured at the large scale model test (standard: $0.3m{\times}0.3m{\times}0.5m$). The scale of model test was 1/14.5 and the ground was excavated in ten steps. Earth pressure on the braced wall and ground surface settlement on the back ground of a braced wall were investigated. The surface settlement during the excavation depended on the joint dips in rocks on of the ratio of rock layer. Maximum earth pressure and maximum surface settlement were masured at the same excavation step. In accordance with the increase of the rock layer dips and rock layer ratio, the ground surface settlement increased. The maximum ground surface settlement was 17 times larger at 60 degree joint dips in rocks than that of the horizontal ground conditions. And the position of the maximum surface settlement by empirical method was calculated at the point, which was 17%~33% of excavation depth. In accordance with the increase of the rock layer dips and rock layer ratio, the ground maximum surface settlement increased. The ground surface settlement of composite ground is smaller than that of the empirical.

• Tuberculosis and Respiratory Diseases
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• v.64 no.6
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• pp.433-438
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• 2008

Background: Measurement of the maximum oxygen uptake in patients with chronic obstructive pulmonary disease (COPD) has been used to determine the intensity of exercise and to estimate the patient's response to treatment during pulmonary rehabilitation. However, cardiopulmonary exercise testing is not widely available in Korea. The 6-minute walk test (6MWT) is a simple method of measuring the exercise capacity of a patient. It also provides high reliability data and it reflects the fluctuation in one' s exercise capacity relatively well with using the standardized protocol. The prime objective of the present study is to develop a regression equation for estimating the peak oxygen uptake ($VO_2$) for men with moderate to very severe COPD from the results of a 6MWT. Methods: A total of 33 male patients with moderate to very severe COPD agreed to participate in this study. Pulmonary function testing, cardiopulmonary exercise testing and a 6MWT were performed on their first visits. The index of work ($6M_{work}$, 6-minute walk distance [6MWD]${\times}$body weight) was calculated for each patient. Those variables that were closely related to the peak $VO_2$ were identified through correlation analysis. With including such variables, the equation to predict the peak $VO_2$ was generated by the multiple linear regression method. Results: The peak $VO_2$ averaged $1,015{\pm}392ml/min$, and the mean 6MWD was $516{\pm}195$ meters. The $6M_{work}$ (r=.597) was better correlated to the peak $VO_2$ than the 6MWD (r=.415). The other variables highly correlated with the peak $VO_2$ were the $FEV_1$ (r=.742), DLco (r=.734) and FVC (r=.679). The derived prediction equation was $VO_2$ (ml/min)=($274.306{\times}FEV_1$)+($36.242{\times}DLco$)+($0.007{\times}6M_{work}$)-84.867. Conclusion: Under the circumstances when measurement of the peak $VO_2$ is not possible, we consider the 6MWT to be a simple alternative to measuring the peak $VO_2$. Of course, it is necessary to perform a trial on much larger scale to validate our prediction equation.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.32-32
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• 2011

최근 국내외에서 친환경건축물에 관한 관심이 매우 높아짐으로 인해 콘크리트의 물량을 절감하여 이산화탄소량을 줄이는 중공슬래브는 다양한 형태로 세계적으로 개발이 되고 있는 추세이다. 특히 이방향 중공슬래브는 환경적인 측면에서 이방향 중공슬래브는 중공부 생성에 재생플라스틱을 활용하여 폐자원을 재사용하고, 콘크리트와 철근의 사용량 절감에 따른 화석에너지 및 이산화탄소 발생량을 감소한다는 장점이 있다. 또한 시스템 측면에서 이방향 중공슬래브는 기존의 철근콘크리트 플랫플레이트 바닥구조 시스템의 자중을 절감하여 구조체를 경량화 시키고, 이에 따라 장스팬 구현이 가능하며, 단열효과가 뛰어나다. 이와 같이 이방향 중공슬래브는 장점이 많지만 플랫플레이트 슬래브의 취약점인 뚫림전단 파괴에 주의해야 한다. 이에 본 연구에서는 선행으로 실시된 이방향 중공슬래브-기둥 접합부 뚫림전단 성능평가 실험을 바탕으로 하여 경량체가 이방향 중공슬래브-기둥 접합부 뚫림전단 성능에 미치는 영향을 살펴보기 위해 범용 유한요소해석 프로그램인 ABAQUS를 사용하여 경량체량 및 위치를 주요변수로 한 해석적인 변화를 검토하였다. 본 연구를 통해 경량체가 삽입된 이방향 중공슬래브의 뚫림전단 성능에 대해, 해석결과 경량체 량과 위치에 따라 최대 뚫림전단강도는 기준 실험체에 비해 74.3%, 73%의 강도저하를 나타내는 것으로 알 수 있었다. 이는 실험상의 강도저하 값인 84.1%, 56.4%와 다소 차이가 있으며, 해석에서 중공부 주위의 응력집중 현상이 제대로 반영되지 않은 것으로 판단된다. 또한 이방향 슬래브에 경량체를 삽입 할 경우 경량체가 시작하는 부분에서 응력이 급격히 감소하는 현상이 나타났으며, 이러한 급격한 응력감소는 기둥 주위 위험단면의 변화를 가져오는 것으로 추정된다. 즉, 위험단면의 변화는 기둥으로부터 경량체 사이의 거리에 따라 달라지며, 위험단면 내의 콘크리트 단면 손실은 뚫림전단 강도를 감소시킨다. 본 연구에서는 이방향 중공슬래브의 뚫림전단강도를 산정할 수 있는 근사식을 제안하였으며, 보다 정확한 이방향 중공슬래브의 뚫림전단강도의 산정식을 위해서는 위험단면의 변화와 콘크리트 단면손실로 인한 전단강도 저하의 관계에 대한 추가적인 연구가 필요하다.