• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.160-162
• /
• 2001

A determining method of the $\Gamma$ type eqivalent circuit parameters of induction motor driven by inverter source is proposed in this paper. The no-load test by rated frequency (60 Hz) and a blocked rotor test by 25% of rated frequency (l5Hz) are performed with inverter source, and the DC resistance of the stator winding is measured. To determine the more accurate parameters, four simultaneous equations obtained from equivalent circuit of the no-load test and blocked rotor test are solved by using initial values which are evaluated from simplified equivalent circuits. The induction motor performances are computed by using these parameters and compared with measured values of the tested motor. Then it is found that the compared results show good agreement between them.

• 대한지하수환경학회지
• /
• 제4권3호
• /
• pp.153-160
• /
• 1997

지하수를 효율적으로 이용하고 보존하기 위해서는 우선 대수층의 투수량계수와 저류계수를 가능한 정확히 평가하여야 한다. 대수층의 수리상수를 결정하기 위한 여러 가지 방법이 본 논문에 소개되었다. 각 방법의 특성을 기술하였으며 각 방법에 의해서 얻어진 결과를 비교하였다. 이를 토대로 자동적으로 대수층의 수리상수를 평가할 수 있는 개선된 방법을 모색하였다.

• 한국농공학회지
• /
• 제33권4호
• /
• pp.61-72
• /
• 1991

A lumped deterministic model(DAWAST model) was developed to predict the daily streamflow. Since the streamflow is dominantly determined by the soil water storage in the watershed, the model takes the soil water accounting procedures which are based on three linear reservoirs representing the surface, unsaturated, and saturated soil layers. The variation of soil water storage in the unsaturated zone is traced from the soil water balance on a daily basis. DAWAST model consists of 5 parameters for water balance and 3 parameters for routing. A optimization technique of unconstrained nonlinear Simplex method was applied for the determination of the optimal parameters for water balance. Model verification was carried out to the 7 hydrologic watersheds with areas of 5.89-7,126km$^2$ and the results were generally satisfactory. The daily streamflow can be arbitrarily simulated with the input data of daily rainfall and pan evaporation by the DAWAST model at the station where the observed streamflow data of short periods are available to calibrate the model parameters.

• Computers and Concrete
• /
• 제5권5호
• /
• pp.449-459
• /
• 2008

This paper focuses on the application of two dimensional orthogonal polynomials in the regression analysis for the relationship of product parameters viz. compressive strength, bulk density and water absorption of fly ash cement bricks with other process parameters such as percentages of fly ash, sand and cement. The method has been validated by linear and non-linear two parameter regression models. The use of two dimensional orthogonal system makes the analysis computationally efficient, simple and straight forward. Corresponding co-efficient of determination and F-test are also reported to show the efficacy and reliability of the relationships. By applying the evolved relationships, the product parameters of fly ash cement bricks may be approximated for the use in construction sectors.

• 한국측량학회지
• /
• 제16권1호
• /
• pp.95-101
• /
• 1998

이 논문에서는 한국경위도원점의 실용성과 및 VLBI 관측점과의 연결에 의한 국제지구기준좌표계94(ITRF94)성과의 결정과정을 설명하고 있으며 이를 이용한 원점변환요소를 도출하고 있다. 또한 실용성과와 31점으로 구성된 지구중심좌표계 KTRF94 성과간의 국가변환요소를 가중변수법을 이용하여 산정하고 결과를 제시하였다. 이 변환요소에 대한 특성을 분석한 결과, 앞으로 KTRF성과를 사용한다면 기선해석의 초기좌표 계산이나 지구중심좌표계의 3차원 성과산정에 활용될 수 있음을 보여주고 있다.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 1987년도 제29회 수공학연구발표회논문초록집
• /
• pp.123-137
• /
• 1987

The groundwater hydrographs due to the recharge of water table aquifer resulting from rainfall are simulated by relating the existing linearized method, which is originally the non-linear equation suggested by Boussinesq, to the basin charcteristics. To thes end, the recharge curve is assumed as the skewed distribution of sine curve, and the parameters contained in the equation are determined from the geomorphologic and soil maps. The whole drainage area is divied in order to consider the spatial variation of parameters. The obtained parameters are tried for several cases with different values given arbitrarily to study the aspects of hydrographs according to their variation. This procedures are applied to the natural basin of Bocheong watershed(area:475.5$\textrm{km}^2$) in Korea. As a result, it is shown that considerable uncertainty is expressed for the results obtained with the given values of parameters. Thus, such uncertainty should be precluded to a certain extent by examining and observing the physical characteristics as much as possible for the determination of groundwater flows.

• Elastomers and Composites
• /
• 제47권3호
• /
• pp.223-230
• /
• 2012

응력완화 실험 곡선을 Eyring-Halsey 비뉴톤 모델의 이론식에 적용하여 poly(methyl acrylate)-poly(acrylonitrile) 공중합체의 유변학적 파라메타를 얻었다. 응력완화 실험은 용매기를 부착한 인장 시험기를 사용하였다. 유동 파라메타를 컴퓨터 프로그램을 이용하여 계산하였다. 이들 시료의 유동 파라메타는 유동 단위의 자체확산, 유동점성, 유동 활성화 에너지와 직접적인 연관을 갖는 것으로 규명되었다.

• Journal of Magnetics
• /
• 제16권3호
• /
• pp.206-210
• /
• 2011

We optimize a vector network analyzer ferromagnetic resonance (VNA-FMR) measurement system to study spin dynamics and Gilbert damping parameters of thin ferromagnetic films. In order to obtain accurate damping parameters, careful determination of the susceptibility line-width is required. The measured S-parameters are converted into the corresponding susceptibility through a calibration processes. From the line-width measurements, we can successfully extract the saturation magnetizations and Gilbert damping parameters of 5-, 8-, and 10-nm thick $Ni_{81}Fe_{19}$ (Py) films.

• 한국방재학회 논문집
• /
• 제6권2호
• /
• pp.61-68
• /
• 2006

지진 매개변수에 의해 지진해일의 초기 수면형상이 결정된다. 본 연구에서는 해저지진에 의해 발생하는 지진해 일의 초기 수면형상의 변화에 대한 지진 매개변수의 영향을 연구한다. 대상 지진해일은 지난 수십 년 동안 우리나라에 가장 큰 피해를 입힌 1983년 동해 중부 지진해일이다. 지진 매개변수 중에서는 strike angle(${\theta}$)이 초기수면형상에 가장 큰 영향을 주었다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
• /
• pp.236-240
• /
• 2001

This paper presents the derivation of model parameters against a comparatively small industrial power plant, and validates its model parameters using the stored data measured at the time of on-site generator characteristic testing. Dynamic models such as generator, excitation system, and turbine/governor are mainly dealt in this paper. For the purpose of validation of derived model parameters, the measured results are compared with simulation results. Those of the comparisons between measured results and simulation results show good match.