• Title/Summary/Keyword: point source model

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Duct Effects on rotor noise in radiation (덕트가 로터 소음 방사에 미치는 영향)

  • Choi, Han-Lim;Chung, Ki-Hoon;Lee, Duck-Joo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.938-941
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    • 2004
  • Sound generation and radiation from the duct-rotor system are calculated numerically. The wake geometries of a two-bladed rotor are calculated by using a time-marching fiee-wake method without a non-physical model of the far wake. Acoustic free field due to a rotating rotor is obtained by Lowson's equation. Using Kirchhoff source, rotating sources are modeled as stationary ones and can be inserted in the thin body boundary element method. The Kirchhoff source is validated through calculation of acoustic pressure due to a rotating point force. The thin body boundary element method (thin body BEM) is validated through calculation of acoustic radiation of ducted dipole. Using Kirchhoff source and thin body BEM, acoustic radiation of a ducted rotating source is calculated. Acoustic shielding is observed by inserting a duct and shows different phenomena at each major frequency. Acoustic radiation of a real duct-rotor system is also calculated using this method and the ducted acoustic field is significantly different from rotor only.

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Passivity-Based Control System of Permanent Magnet Synchronous Motors Based on Quasi-Z Source Matrix Converter

  • Cheng, Qiming;Wei, Lin
    • Journal of Power Electronics
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    • v.19 no.6
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    • pp.1527-1535
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    • 2019
  • Because of the shortcomings of the PID controllers and traditional drive systems of permanent magnet synchronous motors (PMSMs), a PMSM passivity-based control (PBC) drive system based on a quasi-Z source matrix converter (QZMC) is proposed in this paper. The traditional matrix converter is a buck converter with a maximum voltage transmission ratio of only 0.866, which limits the performance of the driven motor. Therefore, in this paper a quasi-Z source circuit is added to the input side of the two-stage matrix converter (TSMC) and its working principle has also been verified. In addition, the controller of the speed loop and current loop in the conventional vector control of a PMSM is a PID controller. The PID controller has the problem since its parameters are difficult to adjust and its anti-interference capability is limited. As a result, a port controlled dissipative Hamiltonian model (PCHD) of a PMSM is established. Thereafter a passivity-based controller based on the interconnection and damping assignment (IDA) of a QZMC-PMSM is designed, and the stability of the equilibrium point is theoretically verified. Simulation and experimental results show that the designed PBC control system of a PMSM based on a QZMC can make the PMSM run stably at the rated speed. In addition, the system has strong robustness, as well as good dynamic and static performances.

Characteristics of Pollution Loading from Kyongan Stream Watershed by BASINS/SWAT. (BASINS/SWAT 모델을 이용한 경안천 유역의 오염부하 배출 특성)

  • Jang, Jae-Ho;Yoon, Chun-Gyeong;Jung, Kwang-Wook;Lee, Sae-Bom
    • Korean Journal of Ecology and Environment
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    • v.42 no.2
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    • pp.200-211
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    • 2009
  • A mathematical modeling program called Soil and Water Assessment Tool (SWAT) developed by USDA was applied to Kyongan stream watershed. It was run under BASINS (Better Assessment Science for Integrating point and Non-point Sources) program, and the model was calibrated and validated using KTMDL monitoring data of 2004${\sim}$2008. The model efficiency of flow ranged from very good to fair in comparison between simulated and observed data and it was good in the water quality parameters like flow range. The model reliability and performance were within the expectation considering complexity of the watershed and pollutant sources. The results of pollutant loads estimation as yearly (2004${\sim}$2008), pollutant loadings from 2006 were higher than rest of year caused by high precipitation and flow. Average non-point source (NPS) pollution rates were 30.4%, 45.3%, 28.1% for SS, TN and TP respectably. The NPS pollutant loading for SS, TN and TP during the monsoon rainy season (June to September) was about 61.8${\sim}$88.7% of total NPS pollutant loading, and flow volume was also in a similar range. SS concentration depended on precipitation and pollution loading patterns, but TN and TP concentration was not necessarily high during the rainy season, and showed a decreasing trend with increasing water flow. SWAT based on BASINS was applied to the Kyongan stream watershed successfully without difficulty, and it was found that the model could be used conveniently to assess watershed characteristics and to estimate pollutant loading including point and non-point sources in watershed scale.

MODELS FOR THE IRAS LOW RESOLUTION SPECTRA OF OH/IR STARS

  • Lee, Sung-Min;Suh, Kyung-Won
    • Journal of Astronomy and Space Sciences
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    • v.15 no.2
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    • pp.291-295
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    • 1998
  • We investigate models for the IRAS LRS)Low Resolution Spectra) of OH/IR stars. OH/IR stars often show the silicate features at 9.7 ${mu}m$ and $18{mu}m$ in the spectra obtained by the IRAS LRS as well as remarkably red values in the IRAS photometric colors such as [60]-[25] and [25]-[12]. We compare the radiative transfer model results with observed spectral energy distributions (SEDs) of the stars including IRAS PSC(Point Source Catalog), IRAS LRS and ground based observational data.

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Stability improvement of induction motor vector control system without speed sensor

  • Tsuji, Mineo;Li, Hanqiang;Izumi, Katsuhiro;Yamada, Eiji
    • 제어로봇시스템학회:학술대회논문집
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    • 1995.10a
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    • pp.207-210
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    • 1995
  • In this paper, two representative schemes for vector control of induction motor without speed sensor are studied. First, the two sensorless systems which are implemented by voltage and current source are presented with new ideas and interpretations. Then a linear model around an operating point is proposed. Finally, the stability improvement of these systems are studied and evaluated by computing the trajectories of poles and zeros.

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Deep learning-based Hologram generation using Amplitude and Phase Component (진폭과 위상을 이용한 딥러닝 기반의 홀로그램 생성)

  • Kang, Ji-Won;Lee, Jae-Eun;Lee, Yoon-Hyuk;Kim, Dong-Wook;Seo, Young-Ho
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2019.06a
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    • pp.227-228
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    • 2019
  • 본 논문에서는 딥 러닝을 기반으로 홀로그램의 연산 간소화를 제안한다. 딥 러닝 중에서도 GAN model을 기반으로 진행된다. Point source 에 대응되는 홀로그램 모델링 식을 이용하여 Amplitude 와 Phase의 Component 들을 각각의 GAN 으로 훈련시켜 얻는 방법을 제안한다.

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CALPUFF Modeling of Odor/suspended Particulate in the Vicinity of Poultry Farms (축사 주변의 악취 및 부유분진의 CALPUFF 모델링: 계사 중심으로)

  • Lim, Kwang-Hee
    • Korean Chemical Engineering Research
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    • v.57 no.1
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    • pp.90-104
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    • 2019
  • In this study, CALPUFF modeling was performed, using a real surface and upper air meterological data to predict trustworthy modeling-results. Pollutant-releases from windscreen chambers of enclosed poultry farms, P1 and P2, and from a open poultry farm, P3, and their diffusing behavior were modeled by CALPUFF modeling with volume sources as well as by finally-adjusted CALPUFF modeling where a linear velocity of upward-exit gas averaged with the weight of each directional-emitting area was applied as a model-linear velocity ($u^M_y$) at a stack, with point sources. In addition, based upon the scenario of poultry farm-releasing odor and particulate matter (PM) removal efficiencies of 0, 20, 50 and 80% or their corresponding emission rates of 100, 80, 50 and 20%, respectively, CALPUFF modeling was performed and concentrations of odor and PM were predicted at the region as a discrete receptor where civil complaints had been frequently filed. The predicted concentrations of ammonia, hydrogen sulfide, $PM_{2.5}$ and $PM_{10}$ were compared with those required to meet according to the offensive odor control law or the atmospheric environmental law. Subsequently their required removal efficiencies at poultry farms of P1, P2 and P3 were estimated. As a result, a priori assumption that pollutant concentrations at their discrete receptors are reduced by the same fraction as pollutant concentrations at P1, P2 and P3 as volume source or point source, were controlled and reduced, was proven applicable in this study. In case of volume source-adopted CALPUFF modeling, its required removal efficiencies of P1 compared with those of point source-adopted CALPUFF modeling, were predicted similar each other. However, In case of volume source-adopted CALPUFF modeling, its required removal efficiencies of both ammonia and $PM_{10}$ at not only P2 but also P3 were predicted higher than those of point source-adopted CALPUFF modeling. Nonetheless, the volume source-adopted CALPUFF modeling was preferred as a safe approach to resolve civil complaints. Accordingly, the required degrees of pollution prevention against ammonia, hydrogen sulfide, $PM_{2.5}$ and $PM_{10}$ at P1 and P2, were estimated in a proper manner.

Inversion of Stochastic Earthquake Model Parameters using the Modified Levenberg-Marquardt′s method in Korea (수정된 Levenberg-Marquardt 역산방법에 의한 한반도 남부의 추계학적 지진 요소 평가)

  • ;Walter Silva
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.03a
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    • pp.20-27
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    • 2002
  • Conventional Levenberg-Marquardt's nonlinear inversion method is simply modified by taking into account the second derivatives of the Hessian matrix so as to give robust inversion results. The weight of the second derivative terms is determined by the value of so-called λ in Levenberg-Marquardt's method. The new inversion method is applied to observed data from small-to-moderate earthquakes to simultaneously evaluate the modes parameters of the stochastic point-source model in and around the Korean Peninsula. Best estimates of the stochastic model parameters are obtained along with their statistics and compared with the previous results. Overall characteristics of the model parameters are found to be more of those of interplate than intraplate tectonic region.

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Simulation of Solar Cell Maximum Power Point Using Matlab (Matlab을 이용한 솔라셀의 최대전력점 시뮬레이션)

  • Lee K.Y.;Kim H.S.;Park J.M.;Cho G.B.;Baek H.L.;Hanyeong College D.H. Kim
    • Proceedings of the KIPE Conference
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    • 2003.07a
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    • pp.204-207
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    • 2003
  • PV model is presented based on the shockley diode equation. The simple model has a photo-current source, an single diode junction and a series resistance and includes temperature dependences. An accurate PV module electrical model is presented, matching with boost converter MPPT strategy and demonstrated in Matlab for a typical general purpose solar cell. Given solar insolation and temperature, the model returns current vector and MPP.

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Development of Pollutants Accumulation Model in Urban Watershed (도시유역내 오염물 축적에 관한 연구)

  • Joo, Jin-Geol;Jun, Hwan-Don;Ryu, Seong-Su;Kim, Joong-Hoon
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.360-364
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    • 2006
  • The physical characteristics of suspended solid in urban watersheds are estimated and are described the accumulation processes on the urban surface. And build up the accumulation model which has two parameters and three constants. Two parameters are $p_0\;and\;p_{max'}$, and three constants are landuse, clean and traffic constant. Suggested model is applied three industry watershed which has variable area. And simulated results are compared with observed data. The model estimates the real phenomenon and the results are pretty good. The simulated accumulation mass are 1.20, 0.96 and $2.88g/m^2$. The differences of simulation and observation data are about 30%.

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