• Journal of the Korean GEO-environmental Society
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• v.12 no.3
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• pp.5-12
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• 2011

In this paper, after studying structural performance for the representative corrugated steel plate used in Korea, we proposed the optimum shape for section of corrugated steel plate considering a width of steel plates that can be produced currently in the factory. Using AISI(1986) in examination for the performance of the corrugated steel plate, we determined the mechanical limit of the optimum sections considering shear force and bending moment of corrugated steel plate and also determined the geometric limit of them considering formability, shapes and ratio between width of steel plate before forming and that after forming. As a result of examination for performance of steel plate applying algorithm for searching optimal sections algorithm developed in this study to the existing representative corrugated steel plate, allowable force and moment of inertia indicated the maximum values at bending radius 76mm and internal bending angle $50^{\circ}$. And as an application result of the optimum design system that used SS490 with 1,550mm of width and 4,700mm of length considering current production situation in Korea, we developed the new section with more than 2 times of structural performance comparing with existing corrugated steel plate.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.3
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• pp.309-318
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• 2004

This research automatically designed psc-box girder bridges by using an optimum design program and applied the results to the various types of bridges to verify if common facts used in steel bridges or concrete bridges can be applied to PSC bridges. Namely, it investigated appropriate unequal span length division by comparing with bridge of unequal and equal span length division, and verified the influence of the load factors which are changed by time or specification applying the results to various types of bridge. and it applied reinforced concrete bridge and steel bridge's variable girder depth which is slender and effective to save material costs to PSC box girder bridges. Technical solution of optimum design program used SUMT procedure, and Kavlie's extended penalty function to allow infeasible design points in the process. Powell's direct method was used for searching design points and a gradient's approximate method was used to reduce the design time.

• Journal of Korean Society of Forest Science
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• v.89 no.2
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• pp.256-259
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• 2000

D.B.H., height, crown length, crown width, crown form, crown area, and crown volume of dead and live trees were measured and the discriminant analysis was conducted to assess individual tree risk-rating in the pine forest seriously infested by the pine needle gall midge. Thecodiplosis japonensis. Crown length, crown form, crown area, and crown volume of live tree were significantly higher than those of dead tree, while D.B.H. and tree height were not different significantly. These results represent that the trees with higher and wider crown and larger crown volume have relatively higher probability to survive from the infestation by the pine needle gall midge. Variables selected in the functions of discriminant analysis were crown area, ratio of crown length, crown form, ratio of crown volume to crown area, and ratio of crown width.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.4
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• pp.1-12
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• 2024

In this study, a determination method of structural member section based on Nonlinear behaviors of steel cable-stayed bridges and the Harmony Search algorithm was presented. The Harmony Search algorithm determines the structural member section of cable-stayed bridges by repeating the process of setting the initial value, initializing the harmony memory, configuring the new harmony memory, and updating the harmony memory to search for the optimal value. The nonlinear initial shape analysis of a three-dimensional steel cable-stayed bridge was performed with the cross-section of the main member selected by the Harmony Search algorithm, and the optimal cross-section of the main members of the cable-stayed bridge, such as pylons, girders, cross-beams, and cables, reflecting the complex behavior characteristics and the nonlinearity of each member was determined in consideration of the initial tension and shape. The total weight was used as the objective function for determining the cross-section of the main member of the cable-stayed bridges, and the load resistance ability and serviceability based on the ultimate state design method were used as the restraint conditions. The width and height ratio of the girder and cross-section were considered additional restraint conditions. The optimal sections of the main members were made possible to be determined by considering the geometry and material nonlinearity of the pylons, girders, and cross-sections and the nonlinearity of the cable members. As a result of determining the optimal cross-section, it was confirmed that the proposed analysis method can determine the optimal cross-section according to the various constraint conditions of the cable-stayed bridge, and the structural member section of the cable-stayed bridge considering the nonlinearity can be determined through the Harmony Search algorithm.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.2
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• pp.1-8
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• 1999

The present paper describes an approximation for estimation of earthquake-induced hydrodynamic loads in rigid storage tank which accelerated in horizontal direction. The storage tank is vertically cylindrical, and the sectional shape may be circular, rectangular or irregular. The solution for harmonic excitation is studied based on velocity potential theory, and then the time domain solution for earthquake is obtained by using design response spectrum. As a result, earthquake load is influenced primarily by the inertia force of high frequency effective mass of the storage tank, responding to the characteristics of design response spectrum, tank sectional shape, and the ratio of tank base length to depth. Earthquake-induced hydrodynamic loads in rigid storage tank can be effectively obtained by using the high frequency approximation method in case of quite large, or small ratio of the tank base length to water depth.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.4
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• pp.83-93
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• 2001

A swirler with turbulence generator is designed and manufactured for generating many small-scale eddies in the combustor which contribute to enhancing mixing effect between fuel and air. The method results in not only the disadvantage of pressure loss but also the advantage of promoting combustion and reducing NOx. For the purpose of the study, four kinds of swirler with different turbulence generator area (0%, 3%, 7%, and 12% of reducing flow area) are designed to confirm the effect of mixing according the variation in the area of the turbulence generator. The mixing of combustor in the radial direction is significantly improved and the distributions of flames and temperature are well distributed throughout the cross section of a combustor as area of swirl generator is increased.

• Korean Journal of Environment and Ecology
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• v.29 no.4
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• pp.590-598
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• 2015

Despite various control methods for pine wilt disease, the disease has been increasing at an alarming rate every year in Korea. Still there is a lack of research on the problems of the current methods used to curb the disease. One main method to control pine wilt disease is fumigation for eliminating the larva of the pine sawyer beetle (Monochamus alternatus) which is known as the vector insect for pine wilt disease. We surveyed and analyzed the amount of destroyed uninfected trees in the fumigated area by studying 32 survey plots ($100m^2$) in Miryang city. The destroyed trees' crown area was estimated by induced regression between root collar area and crown area of the remaining trees (coniferous tree: $R^2=57.4$, deciduous broad-leaved tree: $R^2=63.8$). According to the analysis results, the infected trees (cut trees) were 18.7% and cut trees which were not infected were 35.5% of the total tree population of the study area on the basis of total crown area. In case of pine trees, 8.4% of uninfected trees were cut off but 62% of uninfected deciduous broad-leaved trees including Quercus spp. were affected and damaged during the fumigation process. Since these broad-leaved trees dominate the sub-canopy layer of the forest, this indiscriminate interruption of broad-leaved trees has the adverse effect of depriving the public benefits such as shadow, a cooler weather, controlling humidity, etc.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.553-558
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• 2015

교량의 주탑, 초고층빌딩과 같이 세장비가 큰 대형구조물의 경우 풍하중에 취약한 특성을 지니고 있어서 바람에 의해 직각 방향으로 발산 진동하는 갤로핑(galloping) 현상이 발생하게 된다. 구조물의 진동을 억제하려는 방안으로 단면 형상에 변화를 주어 공기역학적 불안정성을 감소시키는 방법이 사용되고 있다. 본 논문에서는 Edison_CFD를 이용하여 모서리 절단부의 비율과 받음각에 따른 공기력 특성에 대한 전산해석을 수행하였다.

• Journal of Acupuncture Research
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• v.17 no.3
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• pp.69-74
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• 2000

이 연구는 안면마비의 재발환자에 대한 한의학적인 원인 및 발생빈도, 나이분포, 재발기간, 가족력, 당뇨와의 관계를 파악하고자 한 것이다. 안면마비는 한방병원을 찾는 환자의 주요한 질환의 하나로서 침치료에 의해 좋은 효과를 보여왔으며 이에 대한 많은 연구가 있었으나 그 재발율에 대한 구체적인 연구는 없었다. 이에 본 연구에서는 경희의료원 한방병원 침구과에 내원한 안면마비 외래환자를 대상으로 초발, 동측재발, 대측재발로 나누어 단면적 분석연구를 시행하였다. 통계처리는 SPSS 8.0를 이용하였으며 chi-square test를 시행하였다. 544명의 외래환자중 7.4%의 재발율을 나타냈으며 동측재발과 건측재발은 통계상 유의성은 없었다. 또한 재발환자의 남여비에 대한 비율은 통계상 유의성이 없었다. 재발된 환자의 평균나이는 46.8세 이었고 재발기간은 8.74년이었다. 재발된 확률은 40세에서 59세 까지 높게 나타났다. 재발된 원인으로는 과로가 가장 높은 빈도를 보였으며 풍한, 정신적인 원인, 음주순으로 나타났다. 안면마비가 재발된 환자중에 당뇨병의 기왕력이 있는 자는 22.5%였으며 안면마비의 가족력은 42.5%의 높은 비율을 나타내었다.

• Journal of Korean Society of Forest Science
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• v.86 no.2
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• pp.158-166
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• 1997

This study presents the method to quantify the stand structure diversity or homogeneity. Gadow's dbh differentiation(Durchmesserdifferenzierung) is introduced which quantifies the horizontal stand structure by the ratio of the dbh between subject tree and neighbour trees. And new stand structure diversity index based on Lorenz curve, which is made by ratio of tree number and basal area or volume by dbh class, is presented. The horizontal stand structure index based on Lorenz curve has a value from 0 to 1 as Gadow's index, and approximates to 1 if the stand structure has high diversity. In the comparative analysis for performance, the new stand structure index based on Lorenz curve is considered to compare with the Gadow's index for describing the stand structure.