• 한국대기환경학회지
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• 제14권5호
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• pp.411-420
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• 1998

To estimate the dispersion coefficients in a coastal area with complex topography, several schemes using empirical equations expressed with and in lateral and vertical directions, respectively have been examined. Estimation results using these equations and meteorological data obtained from SODAR system were compared' with previously measured dispersion coefficients in other coastal areas. Validations of estimation results have been performed by comparing the measured concentrations with predicted ones empolying in Boryung coastal area. Important conclusions were drawn as follows; (1) Variations of lateral and vertical wind direction revealed different height dependency in upper and lower mixed boundary layer. (2) Because of turbulent constraint effect by large water body in a coastal region, the lateral and the vertical dispersion coefficients were smaller than those of P-G system. (3) As a result of examining the performance measure of these schemes through checking of coincidence between measured and predicted concentrations, vertical dispersion coefficients were smaller than those of P-G system, and the Cramer scheme was found to be more appropriate rather than others in the coastal area surrounding Boryung power plant.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2001년도 추계학술대회 논문집(Proceeding of the KOSME 2001 Autumn Annual Meeting)
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• pp.130-134
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• 2001

In the re-entry control system, errors apt to induce because the time derivative of drag acceleration is analytically estimated. Still more, the difficulty of estimation of the exact drag coefficient in hypersonic velocity and the nun-reality of the scale height cause a steady-state drag error. This paper proposes the additional method of the disturbance observer. This reduces the steady-state drag error according to the following series. First, this method estimates a error in drag acceleration time derivative by the analytic calculation and then creates the new drag acceleration time derivative using the estimated error. The performance of the re-entry control system is verified about 32 reference trajectories.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.330-333
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• 2009

This paper proposes a method to estimate the flow speed of pedestrians in surveillance videos. In the proposed method, the average moving speed of pedestrians is measured by estimating the size of real-world motion from the observed motion vectors. For this purpose, pixel-to-meter conversion factors are calculated from camera geometry. Also, the height information, which is missing because of camera projection, is predicted statistically from simulation experiments. Compared to the previous works for flow speed estimation, our method can be applied to various camera views because it separates scene parameters explicitly. Experiments are performed on both simulation image sequences and real video. In the experiments on simulation videos, the proposed method estimated the flow speed with average error of about 0.1m/s. The proposed method also showed a promising result for the real video.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall
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• pp.170-177
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• 1999

The natural period calculation equations specified in the current building code are empirical formulas that depend on height and material type of the structure. Building with the upper wall and lower frame type is a unique structure which composed of two different structural system This type of structure needs either the deep transfer girder or the thick transfer plate that brings the sudden change of stiffness and mass. Therefore the natural period equations recommended by the current code can not be applied directly. In this study the natural period of building with typical plan obtained by dynamci analysis is compared with that of various codes. Ad approximate estimation equation for the natural period of building with the upper wall and lower frame type obtained by regression analysis is recommended. by the current code can not be applied directly. In this study the natural period of building with typical plan obtained by dynamic analysis is compared with that of various codes, And approximate estimation equation for the natural period of building with the upper wall and lower frame type obtained by regression analysis is recommended.

• 한국해안해양공학회지
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• 제16권4
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• pp.233-240
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• 2004

도파고를 산정하는 경험식을 도출하기 위하여 도파지점에서의 수리조건을 대표하는 수치를 적용한 새로운 무차원수인 파활동경사 $S_x$를 도입하였다. Saville(1958)의 실험자료에 기초하여 사면경사, 파형경사 등과 도파고비와의 관계를 도출하여 수심 구간별로 도파고를 산정할 수 있는 경험식을 제시하였다. 한편 Ahrens(1988) 관측자료와 Mase(1989) 실험자료를 이용하여 조도 영향을 고려하며 광범위한 경사조건에 적용할 수 있는 보다 일반성이 확보된 경험식을 도출하였다. Mase(1989)가 시도한 바와 같이 Iribarren 수를 도입한 경우에는 비선형관계가 유도되어 지수형 산정식이 도출된다. 이에 반하여 지점 파활동경사를 도입하였을 경우에는 단순히 선형 비례하는 간단한 일차식의 형태로 광범위한 수심과 경사 구간에 적용할 수 있는 경험식을 도출할 수 있었다.

• Journal of Nutrition and Health
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• 제28권1호
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• pp.71-83
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• 1995

The purpose of the study was to develop generalized equations for estimating stature and weight for the nonambulatory elderly persons. Height weight recumbent knee height total ann length, midarm, waist and calf circumferences, triceps and subscapular skinfolds were measured from over 60 years old 315 ambulatory elderly. The equations to predict stature and weight were derived from participants in the validation sample and were applied to the participants in the cross-validation to test the accuracy and validity of equations. Stature and weight were significantly and negatively associated with age of women and similar patterns observed in men but associated to a slight degree. Knee height and total arm length were highly correlated with stature but the majority of the variances in stature was accounted for by knee height for both the men and women. In men, waist circumference was the most significantly correlated with weight and am, calf circumferences and so forth. But in women arm circumference was the highest then waist and calf circumference in order. The possible predictor variables to estimate of stature were knee height total arm length and age for both elderly men and women. Predictor variables to estimate of weight were recumbent measures of waist am, calf circumferences and knee height for both sexes. Inclusion of skinfold thickness measurements did not improve the prediction power of estimation for weight. When both equations developed from the present study and Chumlea's study were applied to cross-valida-tions samples, the equations derived from present study showed better accuracy and validity. The presentation of prediction equations using two, three, or four recommended measurements allows the selection of an equation based upon the measurements that are possible to collect on an individual basis.

• 한국산림과학회지
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• 제89권3호
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• pp.414-421
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• 2000

본(本) 연구(硏究)는 경기도 포천군 소흘면에 소재한 23년생(年生)의 방크스소나무 인공림(人工林) 임분(林分)을 대상으로 연년(連年) 재적생장량(材積生長量)과 재적생장율(材積生長率)을 구명(究明)하고 현실(現實) 임분축적(林分蓄積)을 파악(把握)함과 동시에 연년(連年) 재적생장량(材積生長量)을 구명(究明)하므로서 년간 벌채량(伐採量)의 조절(調節)을 합리적(合理的)으로 책정할 수 있으므로 적정(適正) 임목축적(林木蓄積)의 달성(達成) 및 유지(維持)를 위한 기초자료(基礎資料)를 제시(提示)코저 하였다. 본(本) 연구(硏究)에서는 재적생장량(材積生長量)을 합리적(合理的)으로 산출(算出)하기 위하여 표준지별(標準地別)로 흉고직경(胸高直徑), 수고(樹高), 수피후(樹皮厚)와 최근(最近) 10년동안의 core의 길이를 측정하였다. 이들의 측정치(測定値)을 이용하여 직경계별(直徑階別)로 연년(連年) 직경생장량(直徑生長量) 및 95%신뢰폭(信賴幅)의 재적생장량(材積生長量)을 산출(算出)하고 아울러 수고곡선식(樹高曲線式)을 유도(誘導)한 후 본(本) 식(式)을 이용(利用)하여 수고(樹高)값을 산출(算出)하였다. 재적표(材積表)를 이용한 재적산출(材積算出)은 본(本) 수고(樹高)값을 적용(適用)하였다. 본(本) 수종(樹種)의 재적생장관계(材積生長關係)를 구명(究明)한 결과(結果) 연년(連年) 재적생장율(材積生長率)은 7.7%이고 이의 추정오차율(推定誤差率)은 6.1%이었다. 재적(材積)은 ha당 $79.58m^3$이었고 연년(連年) 재적생장량(材積生長量)은 $6.13m^3$이었으며 이를 95%의 신뢰폭(信賴幅)으로 본다면 $5.77{\sim}6.51m^3$이었다.

• 한국산림과학회지
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• 제98권2호
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• pp.178-182
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• 2009

A new mixed-effects model was developed that predicts individual-tree total height for Pinus densiflora trees in Gangwon province as a function of individual-tree diameter (cm). The mixed-effects model contains two random-effects parameters. Maximum likelihood estimation was used to fit the model to 560 height-diameter observations of individual trees measured throughout Gwangwon province in 2007 as part of the National Forest Inventory Program in Korea. The new model is an improvement over fixed-effects models because it can be calibrated to a local area, such as an inventory plot or individual stand. The new model also appears to be an improvement over the Forest Resources Evaluation and Prediction Program for the ten calibration trees used in this study. An example is provided that describes how to estimate the random-effects parameters using ten calibration trees.

• 한국환경과학회지
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• 제21권4호
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• pp.517-533
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• 2012

This study calculated wind speed at the height of 10 m using a disaster prediction model(Florida Public Hurricane Loss Model, FPHLM) that was developed and used in the United States. Using its distributions, a usable information of surface wind was produced for the purpose of disaster prevention when the typhoon attack. The advanced research version of the WRF (Weather Research and Forecasting) was used in this study, and two domains focusing on South Korea were determined through two-way nesting. A horizontal time series and vertical profile analysis were carried out to examine whether the model provided a resonable simulation, and the meteorological factors, including potential temperature, generally showed the similar distribution with observational data. We determined through comparison of observations that data taken at 700 hPa and used as input data to calculate wind speed at the height of 10 m for the actual terrain was suitable for the simulation. Using these results, the wind speed at the height of 10 m for the actual terrain was calculated and its distributions were shown. Thus, a stronger wind occurred in coastal areas compared to inland areas showing that coastal areas are more vulnerable to strong winds.

• 한국수자원학회논문집
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• 제53권12호
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• pp.1211-1220
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• 2020

본 연구에서는 소형 X-밴드 이중편파 레이더의 수평반사도 (ZH), 차등반사도(ZDR), 교차상관계수(ρHV)의 RHI(range height indicator) 연직단면과 PPI (plan position indicator)의 고도각 경사거리(slant range) 빔의 프로파일 분석을 통하여 밝은 띠(bright band, BB)의 특성을 탐색하였다. 분석 결과, X-밴드 레이더의 이중편파 변수들을 이용하여 밝은 띠 영역을 명확히 탐지할 수 있었으며, 동시간대의 RHI 및 PPI 관측 자료를 이용한 이중적인 밝은 띠 영역을 탐색하여 그 결과가 일치함을 확인하였다. 이 결과를 토대로 현업에서 RHI 관측없이 PPI 볼륨관측만 수행하는 대형 강우레이더에도 본 연구의 PPI 고도각 경사거리에 의한 BB 탐색 방법을 적용함으로써 QPE (quantification of precipitation estimation)의 정확성을 향상시킬 수 있다.