• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.1048-1052
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• 2003

This study aims to derive frequency weighting curves for the estimation of driver's discomfort by steering wheel vibration in the vertical and rotational direction with respect to a steering column. Subjective tests for the determination of equal sensation curves, inverse of frequency weighting curves, for the two kinds of vibrations were performed using the sinusoidal signals with reference amplitudes from 0.2m/s$^2$ to 0.4 m/s$^2$ in the frequency range from 5㎐ to 100㎐. Twelve subjects joined at the tests, and median values of the twelve judgments were used to determine the frequency weighting curves. Second experiment was followed to determine relative magnitude between the two frequency weighting curves by direct comparison of discomfort due to the two kinds of vibrations at 50㎐, which showed discomfort by the rotational vibration was 1.5 times of that by the vertical vibration.

• 조명전기설비학회논문지
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• 제25권5호
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• pp.22-33
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• 2011

An induction motor operated with a conventional direct self controller(DSC) shows a sluggish response during startup and under changes of torque command. Fuzzy logic controller(FLC) is used in conjection with DSC to minimize these problems. A FLC chooses the switching states based on a set of fuzzy variables. Flux position, error in flux magnitude and error in torque are used as fuzzy state variables. Fuzzy rules are determinated by observing the vector diagram of flux and currents. This paper proposes hybrid fuzzy controller for direct torque control(DTC) of induction motor drives. The speed controller is based on adaptive fuzzy learning controller(AFLC), which provide high dynamics performances both in transient and steady state response. Flux position, error in flux magnitude and error in torque are used as FLC state variables. The speed is estimated with model reference adaptive system(MRAS) based on artificial neural network(ANN) trained on-line by a back-propagation algorithm. This paper is controlled speed using hybrid fuzzy controller(HFC) and estimation of speed using ANN. The performance of the proposed induction motor drive with HFC controller and ANN is verified by analysis results at various operation conditions.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권3호
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• pp.300-305
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• 2013

The torque was calculated with inductance and iron loss. Because the linkage flux can change the inductance, and q-axis current can change the iron loss. Therefore, precise estimation of torque can achieve with the inductance and iron loss detail calculations. So, in this paper, the d, q-axis inductance was verified through CVCT(Current Vector Control Test) and DCT(Direct Current Test). Also in the iron loss calculation, the prediction of all areas of current magnitude, phase angle and speed was very difficult. And LUT(Look-Up Table) was spent time and resource largely. Therefore, iron loss mathematization was proposed according to current magnitude, phase angle and speed. Also, characteristics of IPMSM were comprised of analyzed and experimental values.

• 한국산학기술학회논문지
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• 제20권4호
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• pp.517-522
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• 2019

본 논문은 전동기 상수 추정 방법을 제안한다. 제안하는 기법은 전동기 전압방정식을 차동식 형태로 전개한 수식에 기반한다. 차동식 형태를 이용함으로써 전동기 상수 추정시 사용되는 전압 정보에 존재하는 크기 오차인 데드타임의 영향을 배제한다. 전동기의 상수값은 전동기 제어 성능 향상을 위해서 필요할 때가 있다. 예를 들면 DTC(Direct Torque Control) 제어 기법에는 토오크 및 자속 크기의 연산시 전동기의 상수를 알아야한다. 다른 예로서 예측제어의 경우 지령치 전압 생성을 위해서는 정확한 전동기의 상수 값의 정보가 필요하다. 전동기의 상수는 구동 환경에 따라 변동하는 값이므로 부정확한 전동기 상수 사용시 제어 성능의 저하를 가져온다. 따라서, 정확한 전동기 상수의 추정이 필요하다. 제안하는 기법에서 전압차동식에 기초하여 추정되는 전동기 상수는 RLS(Recursive Least Square) 기법에 의해 구해진다. 본 연구에서는 단순 수식에 의한 형태로 전동기의 상수를 추정하지 않고, RLS 알고리즘을 적용하여 노이즈에 강인하게 전동기 상수를 추정한다. 표면 부착형 영구자석 전동기의 제어시스템에 적용하여 제안하는 기법의 타당성을 보인다.

• 말소리와 음성과학
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• 제15권3호
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• pp.59-67
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• 2023

본 연구는 연장음의 길이에 따른 비유창성 지각 정도에 대해 각각 등간척도와 직접크기평정을 통한 청지각적 평가를 실시한 후, 두 평가의 결과치가 선형적인 또는 비선형적인 관계를 보이는지를 알아보고자 진행되었다. 이를 통해 연장음의 길이에 따른 비유창성 지각 정도에 대한 적절한 평가 방법을 제안하고자 하였다. 이를 위해 한국어를 모국어로 하는 만 19세 이상 성인 남녀 34명(남: 9명, 여: 25명, 평균연령: 32.9세)이 평가자로 참여였다. 실험참여자는 먼저 한국어 평마찰음 /s/를 원래 길이에서 80 ms씩 연장하여 2,000 ms(i.e., 285 ms, 365 ms., ..., 2,125 ms, 2,205 ms)까지 연장 변조한 총 25개의 자극이 들어 있는 문장을 듣고, 등간척도(1-7점, 1은 '정상', 7은 '심도')로 평가하였다. 이후에 등간척도 평가 결과, '경중도'(4점)에 해당하는 음성샘플을 선정해 이를 기준 평가치(modulus)로 하여 직접크기평정을 실시하였다. 두 평가 결과치에 대한 산포도를 작성한 후, 모형 분석을 통해 두 측정치 간의 관계가 선형적(linear)인지 비선형적(curvilinear)인지 R²값을 통해 조사하였다. 연구 결과, 두 평가 결과치의 관계가 비선형적인 양상을 보이는 것으로 나타났으며 이는 연장음의 길이에 따른 비유창성 정도 평가에 있어 등간척도보다는 직접크기평정이 적절한 평가 방법임을 보여주는 결과이다.

• Asian-Australasian Journal of Animal Sciences
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• 제22권7호
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• pp.931-936
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• 2009

Body weights of 862 Angora goats between birth and 36 months of age, recorded on a semiyearly basis from 1988 to 2000, were used to estimate genetic, permanent environmental and phenotypic covariance functions. These functions were estimated by fitting a random regression model with 6th order polynomial for direct additive genetic and animal permanent environmental effects and 4th and 5th order polynomial for maternal genetic and permanent environmental effects, respectively. A phenotypic covariance function was estimated by modelling overall animal and maternal effects. The results showed that the most variable coefficient was the intercept for both direct and maternal additive genetic effects. The direct additive genetic (co)variances increased with age and reached a maximum at about 30 months, whereas the maternal additive genetic (co)variances increased rapidly from birth and reached a maximum at weaning, and then decreased with age. Animal permanent environmental (co)variances increased with age from birth to 30 months with lower rate before 12 months and higher rate between 12 and 30 months. Maternal permanent environmental (co)variances changed little before 6 months but then increased slowly and reached a maximum at about 30 months. These results suggested that the contribution of maternal additive genetic and permanent environmental effects to growth variation differed from those of direct additive genetic and animal permanent environmental effects not only in expression time, but also in action magnitude. The phenotypic (co)variance estimates increased with age from birth to 36 months of age.

• 한국소음진동공학회논문집
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• 제23권6호
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• pp.563-573
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• 2013

The ship radiated noise level fluctuates by the interference between direct and reflected paths. The effect of sea surface reflection path on interference depends strongly on sea surface roughness. This paper describes error characteristics of ship acoustic signature estimation by sea surface scattering effect. The coherent reflection coefficient which explains a magnitude of sea surface scattering and its resultant interference acoustic field is analyzed quantitatively as a function of a grazing angle, effective surface height, frequency, source-receiver range and depths of source and receiver. Theoretical interference acoustic field is compared with experimental result for two different sea surfaces and five different frequencies by changing source-receiver range. It is found that both matches well each other and a magnitude of interference acoustic field is decreasing by increasing a grazing angle, effective surface height, frequency, and depths of source and receiver and decreasing source-receiver range. For given experimental conditions, the transmission anomaly which is a bias error of ship acoustic signature estimation, is about a range of 1~3 dB. The bias error of an existing ship radiated noise measurement system is also analyzed considering wind speed, source depth and frequency.

• 한국지진공학회논문집
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• 제27권6호
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• pp.311-320
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• 2023

When an earthquake occurs, the severity of damage is determined by natural factors such as the magnitude of the earthquake, the epicenter distance, soil properties, and type of the structures in the affected area, as well as the socio-economic factors such as the population, disaster prevention measures, and economic power of the community. This study evaluated the direct economic loss due to building damage and the community's recovery ability. Building damage was estimated using fragility functions due to the design earthquake by the seismic design code. The usage of the building was determined from the information in the building registrar. Direct economic loss was evaluated using the standard unit price and estimated building damage. The standard unit price was obtained from the Korean Real Estate Board. The community's recovery capacity was calculated using nine indicators selected from regional statistical data. After appropriate normalization and factor analysis, the recovery ability score was calculated through relative evaluation with neighboring cities.

• 한국지진공학회논문집
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• 제20권6호
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• pp.391-400
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• 2016

For earthquake loss estimation of building structures in Gangnam-Gu district in Seoul, three scenario earthquakes were selected by comparison of the response spectra of these scenario earthquakes with the design spectrum in Korean Building Code (KBC 2009), and then direct losses of the building structures in the Gangnam-Gu district under each scenario earthquake are estimated. The following conclusions are drawn from the results of damage and loss in the second scenario earthquake, which has a magnitude = 6.5 and epicentral distance =15 km: (1) The ratio of building stocks undergoing the extensive and complete damage level is 40.0% of the total. (2) The amount of direct economic losses appears approximately 19 trillion won, which is 1.2% of the national GDP of Korea. (3) About 25% of high-rise (over 10-story) RC building wall structures, were inflicted with the damage exceeding moderate level, when compared to 60% of low-rise building structures. (4) From the economical view point, the main loss, approximately 50%, was caused by the damage in the high-rise RC wall building structures.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.293-296
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• 2002

This paper presents an implementation of Direct torque control(DTC) of Reluctance Synchronous Motor(RSM) drives for an industrial servo drive system with stator current space vector. The estimation of the stator flux magnitude are obtained by using the neural network from measuring the modulus and angle of the stator current space vector. The develolled digitally high-performance control system are shown a good response characteristic of control results and high performance features using 1.0kW RSM.