• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.205-208
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• 2008

The wind load on building surface is numerically investigated. The geometry of target building is a square cross section and aspect ratio (height (H) to width (d)) is 6. On building surface, the pressure was measured, compared to obtained value from numerical simulation. The numerical simulations were done using URANS with three different turbulence models such as v2-f model, k-${\omega}$model, and k-${\varepsilon}$ model, respectively. The v2-f model showed the best agreement with experimental data in simulating mean pressure coefficients on front, rear and side surface. But unsteady characteristics of pressure history measured on surface is shown a discrepancy between experiment and numerical simulation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.711-716
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• 2008

A circular tube undergoes bucking behavior when it is subjected to axial loading. An upper bound analysis can be an attractive approach to predict the buckling load and energy absorption efficiently. The upper bound analysis obtains the load or energy absorption by means of assumption of the kinematically admissible velocity fields. In order to obtain an accurate solution, kinematically admissible velocity fields should be defined by considering many factors such as geometrical parameters, dynamic effect, etc. In this study, experiments and finite element analyses are carried out for circular tubes with various dimensions and loading conditions. As a result, the kinematically admissible velocity field is newly proposed in order to consider various dimensions and the strain rate effect of material. The upper bound analysis with the suggested velocity field accurately estimates the mean load and energy absorption obtained from results of experiment and finite element analysis.

• Asian-Australasian Journal of Animal Sciences
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• 제14권8호
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• pp.1062-1066
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• 2001

Studies were carried out on forty young bulls of the Hariana breed (around 18 months of age) selected on the basis of their dam's milk yield at the animal farm of CCS HAU, Hisar during the period 1993-1999. Since animals showed variation in capacity to work over prolonged periods, they were subjected to regimes of carting without load and with 8 qtls. of load for three hours. The study revealed that maximum change took place in the pulse rate, followed by respiration rate and rectal temperature. The mean fatigue score for pulling an empty cart ranged between 1.66 to 2.20 after two hours work, and 2.36 to 2.73 after three hours work. For a cart loaded with 8 qtls., the corresponding ranges were 2.90 to 3.36 and 3.40 to 4.10, respectively. These results indicated that the animals under experiment had the capacity to pull moderate load (8 qtls.) for about two hours without showing any serious effect on the ability to recover and soon to work again.

• 농촌계획
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• 제9권1호
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• pp.77-83
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• 2003

This study was carried out to provide the basic information for the water quality management of the Sumjin River Basin. The Chooryeongchon stream watershed was selected and the parameters representing water quality were investigated from May 1999 to September 2002, periodically. Yearly mean runoff ratio to the rainfall amount of the watershed was analysed as $26.6{\sim}58.8%$. Temporal variation of water quality constituents such as water temperature, pH, EC, total nitrogen, total phosphorus were analysed. The result showed that pH ranged $5.7{\sim}7.7$, EC $54{\sim}167\;{\mu}S/cm$, COD $0.8{\sim}18.1\;mg/L$, respectively. Total-N and total-P concentration ranged from 0.89 to 5.19 mg/L and from 0.0004 to 0.030 mg/L, respectively. The relationships between runoff and mass load were derived and showed high linear relationships.

• 에너지공학
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• 제6권1호
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• pp.68-76
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• 1997

본 논문에서는 단기 부하예측을 위하여 인공신경망 모형을 제안하였다. 본 논문에서 제안된 인공신경망의 학습알고리즘은 기존의 역전파 알고리즘 보다 효과적으로 학습수렴이 빠르며 모수결정과 초기가중치 값들에 대한 의존도가 낮은 동적 적응 학습알고리즘을 개발하여 단기 부하예측에 그 적용 가능성을 시험하였다.

• 한국정밀공학회지
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• 제15권10호
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• pp.88-95
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• 1998

The purpose of this study is to predict the life of a Lug under the real service load history. The techniques of predicting a fatigue life under load spectrum are discussed and some are developed. The stress is calculated by multiplying the stress under unit force with the Finite Element Analysis. The cycles are counted by the Rainflow counting method and then the mean stress effect is considered by the suggested conversion function. The Manson's Double Linear Damage Rule is used as the cummulative damage method.

• 대한의용생체공학회:의공학회지
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• 제6권1호
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• pp.19-30
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• 1985

This paper describes the EMG signals in frequency domain using power spectral density, The changes in the moan frequency can represent the energy distribution which results from changing in load before and during fatigue. Most of EMG signal power spectrum is located between 10 and 200Hz. Shifts of the high-energy regions of the power spectra can be inferred from the changes in the mean frequency. If the load is increased without fatigue-ocurring, the high frequency regions have more energy than the low frequency regions. And if load is increased during fatigue, the low frequency regions have more energy than the high frequency regions.

• 대한전기학회논문지:전력기술부문A
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• 제52권8호
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• pp.450-456
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• 2003

This paper proposes a multiple time-series model with dummy variables for one-hour ahead load forecasting. We used 11 dummy variables that were classified by day characteristics such as day of the week, holiday, and special holiday. Also, model specification and selection of input variables including dummy variables were made by test statistics such as AIC(Akaike Information Criterion) and t-test statistics of each coefficient. OLS (Ordinary Least Squares) method was used for estimation and forecasting. We found out that model specifications for each hour are not identical usually at 30％ of optimal significance level, and dummy variables reduce the forecasting error if they are classified properly. The proposed model has much more accurate estimates in forecasting with less MAPE (Mean Absolute Percentage Error).

• 한국멀티미디어학회논문지
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• 제20권5호
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• pp.800-807
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• 2017

The Pattern Sequence-based Forecasting (PSF) is an approach to forecast the behavior of time series based on similar pattern sequences. The innovation of PSF method is to convert the load time series into a label sequence by clustering technique in order to lighten computational burden. However, it brings about a new problem in determining the number of clusters and it is subject to insufficient similar days occasionally. In this paper we proposed an adaption of the PSF method, which introduces a new clustering index to determine the number of clusters and imposes a threshold to solve the problem caused by insufficient similar days. Our experiments showed that the proposed method reduced the mean absolute percentage error (MAPE) about 15%, compared to the PSF method.

• 한국물환경학회지
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• 제27권5호
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• pp.597-604
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• 2011

This research analyzed the runoff patterns and estimated unit loads of selected pollutatnts using monitored data conducted for three years in a bridge area. Three estimating methods; the arithmetic average method, the regression method and the rainfall class method were used to estimate the unit load. Results of three estimating methods were compared with the unit pollutant loads from landuses in Korea and the unit pollutant loads from urban watersheds in Milwaukee, USA. Unit load using the arithmetic mean method were found to be overestimated. In terms of TSS, unit loads of two estimate were half lower than that of USA. Estimated TN and TP unit loads of three estimate were lower than that of Ministry of Environment in Korea.