• 한국환경과학회지
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• 제30권6호
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• pp.475-485
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• 2021

This research investigated the characteristics of fine particles during cold front passage in Busan, on March 19, 2020. The cold front speed was 17.4 m/s (about 63k km/hr), moving from the northwest to the southeast, and with a width of about 64 km. The backward trajectory analysis showed that a southern sea air parcel flowed into Busan before the cold front passage, carrying continental materials from China transported into Busan after cold front passage. The PM₁₀ concentration in Busan showed a rapid increase after passing through the cold front, with PM_2.5 showing a high concentration during cold front passage. The PM_2.5/PM₁₀ ratio was 0.10 - 0.30. When the cold front passed, SO₄^2-, NO₃^-, Ca²⁺, NH₄⁺, Na⁺, and K⁺ in PM_2.5 showed a rapid increase, with SO₄^2- showing the most significant increase. These results indicated that understanding the characteristics of fine particles during cold front passage in Busan could provide insight into establishing a strategy to control urban air quality.

• 자동차안전학회지
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• 제6권2호
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• pp.5-11
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• 2014

Front side member of the front impacted vehicle plays a key role in minimizing the impacting load transferred to the compartment. To perform that required function, axial collapse should be dominant during side member crashing and, prior to designing side member, it is crucial to minimize bending moment occurred at the front end. In this study, for FE model of a SUV front body, front impact analyses were carried to find out bumper stay design which effectively develope axial collapse in the side member. As a previous work, the thickness of side member reinforcement were changed. Next, the inner thickness of bumper stay was increased. Also, the bead shape and location were modified. Final front body model showed much more axial collapsed mode and enhanced crash performance. In addition, a stay of octagon section was adopted and that model exhibited distinctive increase in impact energy absorption.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.398-402
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• 2007

본 연구에서는 삼각 요소망을 구성하는데 사용되는 기존의 Delaunay Triangulation 기법 외에 Advanced Front Technique 알고리즘을 적용하여 하천의 경계가 중요시되는 해석 모델에 적합한 삼각 요소망을 생성하고자 한다. Advanced Front Technique 알고리즘은 외부 경계를 따라 삼각 요소를 형성하기 시작하여 전체 해석 영역으로 요소를 채워가는 방법이다. 이 방법은 위에서 언급한 Delaunay Triangulation 기법의 단점인 해석 영역의 경계에서 요소의 형질이 좋지 못한 문제를 극복할 수 있을 뿐만 아니라, 미리 절점을 생성하지 않으므로 메모리를 절약하는 효과도 얻게 된다. Advanced Front Technique 알고리즘은 외부 경계의 노드(i)와 노드(i+1)을 Front로 하고, 이등변삼각형을 이루기 위해 해석 영역 내부의 적절한 위치에 새로운 절점(C)을 생성한다. 이렇게 Front와 새로운 절점(C)으로 이루어진 이등변 삼각형 요소가 생성된 후에, Front는 다음 Front로 전진하면서 점차 해석 영역의 내부로 삼각형 요소를 채우게 된다. 이와 같은 방법에 의해서 해석영역의 경계에서는 비교적 이등변 삼각형에 가까운 삼각 요소가 생성된다.

• 자원환경지질
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• 제38권3호
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• pp.285-297
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• 2005

미국 오하이오주에 있는 Grenville Front의 위치와 특성을 이해하기 위하여 중자력, 탄성파 및 지질자료를 이용한 지구물리학적 연구를 수행하였다. 탄성파 자료에 의하면 서부 오하이오에서의 기반암은 Grenville Front와 관계가 있는 동쪽으로 경사를 이루는 반사면으로 나타나고 이에 반하여 동부 오하이오에서는 서쪽으로 경사를 이루는 반사면이 나타난다. 중자력 자료 분석에 의하면 Grenville Front는 저중력 이상으로 그리고 Grenville Front Tectonic Zone은 고중력 및 고자력 이상으로 특징 지워진다. 탄성파 자료를 근거로 수행한 중자력 모델링 결과는 Grenville Front위치에서 하부지각은 두껍고 Grenville Front Tectonic Zone은 주로 변성도가 높은 변성암으로 구성된다는 것을 제안한다. Grenville Front 위치에서 저중력 이상은 두터운 지각 두께 때문에, 반면에 고자력 이상은 변성도가 높은 변성암들의 존재 때문인 것으로 해석된다. Grenville Front 바로 동쪽의 오하이오 중앙부에서 나타나는 고중력 이상은 밀도가 높은 하부 및 중부 지각이 상부지각으로 트러스팅 (thrusting) 되었기 때문이다. 과거 연구에서는 이 고중력 이상이 선캄브리아대의 열 개지역과 관계된다고 하였는데 이를 뒷받침할 만한 근거는 없다.

• 한국의상디자인학회지
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• 제18권1호
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• pp.169-181
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• 2016

This study analyzed the characteristics and patterns of men's drawers panties to get basic data for their design. For this, drawers panties in 7 different brands (4: domestic brands, 3: imported brands) in terms of a front-center shape were collected, and the shape of men's drawers panties, characteristics of the materials, dimensions & type of patterns by the part and front-center patterns were analyzed. The study results found the followings: First, in terms of the shape of men's drawers panties, the front-center part were designed to rest the penis and scrotum in a natural and comfortable manner without a pee slit. They were seamless on the sides except for one product with side seams. Second, the drawer panties were made of elastic polyurethane materials. Specifically, domestic brand items used warm, elastic and durable nylon, polyester and rayon and polyurethanes while imported brands were mostly made of absorbent and sanitary polyurethanes. Third, regarding a size of drawer panties by part, imported brands were large in waist circumference. In terms of waist breadth at the front center, there was difference depending on an oval type. In addition, the front length at the front center differed by product, revealing difference in three-dimensional effect at the front center. The side length also differed greatly by product, which means that there might be a great difference in wear comfort. Fourth, in terms of the patterns of men's drawers panties, there was difference in side seams, center back seam and front-center patterns. Among a total of 7 products, only one product had side seams, and center back seams were found in two products only. Fifth, in terms of front-center patterns, the drawer panties can be divided into three types, creating three-dimensional effect not to give any pressure on the crotch: i) the cutting line only at the bottom of the front center part where the penis is rested, ii) puff created at the front center by adding a transverse line to the center line, iii) cutting transverse line to separate the penis from the testicles.

• 한국자동차공학회논문집
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• 제10권1호
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• pp.209-215
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• 2002

A study of the guideway vehicle was made for a comparison of ride stabilities between its two primary steering types; one is the front wheel steering and the other the front-rear wheel. A numerical model as a closed loop system was built for an investigation of various factors to have an influence on the vehicular critical speed which is closely associated with ridabilities. It was shown that dynamics stabilities of the front steering type was much better over a large value of steering gain and the longer distance between front axle and guide link for both types provided better stabilities as well. A large steering gain ratio of the front to the rear significantly plays an important role in an improvement of stability in the front-rear steering. To observe a qualitative trend on stability behaviors, the root locus was obtained by considering a time lag which may be frequently caused by the complicated steering mechanism. In performing so, the appropriate selection of steering gain had a greater effect on the front-rear steering vehicle far more ride comfort. In addition, the dynamics model proposed here can be utilized for a more accurate evaluation on the vehicle design in lateral or yawing absorber and moreover expanded for the analysis of independent four-wheel steering vehicle.

• 대한산업공학회지
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• 제18권1호
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• pp.25-36
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• 1992

A possible adverse effect on the likelihood of front-seat occupant fatalities from unbelted rear-seat occupants in frontal crashes is investigated using Fatal Accident Reporting System data. Passenger cars which sustained frontal damage and which did not roll over are included in this analysis. Of the frontally damaged cars, only cars containing a driver and a right-front passenger are selected. Then, from these cars, the following three cases are considered: a) left-rear occupant present, b) right-rear occupant present, and c) no one else in the car. Cars belonging to a) or b) contain only three occupants, and those belonging to the last case contain only two occupants. In addition, all occupants are unbelted. To estimate the influence of rear-seat occupants on front-seat occupant fatalities, relative risks of driver and right-front passenger fatalities are compared pairwise across these three cases. The adverse influence of unbelted rear-seat occupants on the likelihood of unbelted front-seat occupant fatalities in frontal crashes is estimated to be 7.9% ${\pm}$ 45%(the error limits indicate one standard error). In other words, front-seat occupant fatalities are increased 7.9% in frontal crashes due to the loadings from unbelted rear-seat occupants. This suggests that the usage of safety belts by rear-seat occupants not only may extend their own lives but also helps in reducing the fatalities of front-seat occupants seated in front of them.

• 한국해양학회지
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• 제25권2호
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• pp.84-95
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• 1990

CTD, 해류계, 인공위성 영상사진을 이용하여 황해 중부의 조석전선 주변역을 조사 한 결과 몇 가지 물리적 특성을 알 수 있었다. 전선은 태안반도 끝 부분을 중심으로 하여 4월 중에 태양열에 의한 해표면 가열과 함께 나타나기 시작하여 8월에 가장 뚜렷 하며 11월에는 표층냉각과 함께 소멸한다. 전선의 북측에서는 전선을 가로지르는 조류 에 의하여 수온 염분의 조석주기 변화가 나타남으로써 전선구조를 보여준다. 경기만에 서 나타나는 전선은 통최상의 조석전선과 달리 한강에서 유출된 담수와 외양수의 만남 에 의하여 형성된다. 표층냉수의 중심에서는 조석혼합역이 연안으로부터 약 50 km 외 양하지 분포한다. 전선의 남측에서도 전선의 구조는 비슷하나 전반적으로 혼합 정도가 약하게 나타난다. 이 연안 혼합역의 연안쪽에서는 금강유출된 담수에 의하여 염분전선 이 좁은 범위에서 흥성된다. 이 염분전선 부근의 일부에서는 용승과 같은 현상이 관측 되었다.

• 한국의상디자인학회지
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• 제18권3호
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• pp.71-83
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• 2016

This study attempted to analyze trends of structural changes in the front middle part of men's underwear and get basic data for the development of men's underwear patterns. In terms of a research method, the structure and pattern of the front middle part of men's underwear were analyzed by referring to the design and description of the drawing, focusing on men's underwear which targeted to isolate penis from scrotum among the 'men's underwear' or 'functional men's underwear'-related patents. According to the study, three topics were obtained as follows: a support attached to the inside of the front middle part; inner cloth attached to the inside of the front middle part; change in the structure of the front middle panel. The aspects by the specific topic targeted to isolate penis from scrotum and prevent the scrotum from adhered to a thigh are as follows: 1) When a support is attached to the inside of the front middle part, the following three methods are proposed: Penis isolated from scrotum by a rest which is designed using the band; penis and scrotum rested in the band and in a pocket respectively; protruded rest inside the front middle part of the underwear. 2) When an inner cloth is attached to the inside of the front middle part, the following methods are designed: A pocket-type inner cloth is attached; isolation of penis hole from the scrotum pocket using a rectangular separator; U-shaped pocket designed to rest penis and scrotum is attached. 3) Regarding change in the structure of the front middle panel, the integration of penis and scrotum resting parts can be divided into two cases: Securing a space using wrinkles; keeping it voluminous using the vertical line. In this all-in-one penis and scrotum-holding type, in addition, different front panel patterns were applied.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.1634-1638
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• 2008

하천의 2차원 흐름 해석, 유사이동 해석, 오염확산 해석을 위한 유체의 수치해석법에는 유한요소법, 유한차분법, 유한차분법의 변형인 유한체적법, 경계적분법 등이 있다. 유체에 대한 수치해석 기법으로 전통적으로 가장 많이 사용되고 있는 방법은 유한차분법이지만, 비구조적 요소망(unstructured mesh)을 이용하여 복잡한 형상을 표현하기가 상대적으로 용이한 유한요소법이 다양한 형태의 하천 해석에는 더욱 적합할 것이다. 본 연구에서는 비구조적 요소망을 advanced front method를 이용하여 생성해 보았다. Advanced front method는 해석하고자 하는 영역에 적절한 절점들을 생성한 후 삼각 요소망을 구성하는 grid based advanced front method와 절점들을 생성하지 않고 해석 영역에 삼각 요소를 바로 구성하는 element based advanced front method로 나눌 수 있다. Grid based advanced front method에서 해석 영역에 적절한 절점을 생성하는 방법으로는 일반적인 격자 구조의 절점 생성 방법을 적용하였으며 경계와의 거리가 가까운 절점은 생성되지 않으며, 삼각 요소를 구성할 때에는 두 개의 인접 절점을 비교하여 최적의 삼각 요소를 구성하게 된다. 단 두 개의 인접 절점만을 비교함으로서 비교적 빠른 시간 안에 최적의 삼각 요소망을 구성할 수 있다. 삼각 요소망을 생성한 후에는 Laplacian smoothing을 이용하여 삼각 요소망의 형질을 개선하였다. Element based advanced front method는 외부 경계에서부터 시작된 Front가 내부 영역으로 확대되어지며 각 Front에서 적절한 절점을 직접 생성하여 바로 삼각 요소를 구성하게 된다. Front에서 생성된 절점은 인접 절점들이 있는지 검색하여 인접 절점이 있다면 생성된 절점은 삭제되어지며 인접 절점이 삼각 요소를 위한 나머지 한 점으로 채택되어진다. Front는 외부 경계와 교차되어지지 않아야 하며 또한 연속된 Front를 효율적으로 관리하기 위해 list 자료 구조를 활용하였다.