• 한국정보처리학회논문지
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• 제6권1호
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• pp.247-252
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• 1999

낮은 Bit Rate의 음성부호화 방식을 구현하기 위해 필요한 파라메터로서 피치정보가 있다. 연속음성에서 정규화 된 피치정보를 추출하는 방법에서는 음성의 시작이나 끝부분, 무성음 혹은 무성자음과 유성음이 같이 존재하는 프레임, 프레임 경계부에서 피치추출 오류가 발생한다. 이러한 오류를 억제하기 위하여 본 연구에서는 FIR-STREAK 필터의 출력 잔차신호에서 피치정보를 얻는 개별 피치추출법을 제안하였다. 이 방법은 피치정보를 정규화하지 않고 연속적으로 변위하는 피치간격을 적절하게 나타낼 수 있다. 실험결과, 개별 피치추출법은 음성의 시작이나 끝부분, 무성음 혹은 무성자음과 유성음이 같이 존재하는 프레임, 프레임 경계부에서도 유효한 피치정보를 얻을 수 있음을 알 수 있었다. 이 방법은 음성부호화방식, 음성분석, 음성합성, 음성인식등에 응용할 수 있을 것으로 기대된다.

• 한국대기환경학회지
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• 제26권4호
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• pp.392-402
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• 2010

Black carbon (BC) concentrations were measured with an aethalometer (AE-16, 880 nm) at time interval of 5-min at an urban site of Gwangju over a year 2008. 24-hr filter-based integrated measurements of $PM_{2.5}$ particles were also made at the same site during the winter and summer intensive periods to test any optical loading bias in the raw BC data measured by aethalometer. BC concentration was higher in winter than in summer, possibly due to increase in emissions from energy consumption and poor dispersion with reduction of boundary layer in winter. Also temporal cycles of BC indicate that short-term transient spikes were common, occurring primarily during the rush-hour periods. A similar feature was also observed in diurnal concentration cycle of CO, mainly emitted from motor vehicles. When both low wind speed and weather patterns such as mist, haze and etc were combined, high BC concentrations frequently occurred. The amount of optical loading effect described by the "k" factor showed the seasonal variation, ranging from 0.0003 to 0.0036. This implies that optical loading effect is not seen at all times. From the comparison between the filter-based elemental carbon (EC) and aethalometer BC data, it was found that the loading compensated BC values were more reasonable than the raw BC ones reported from the aethalometer.

• Journal of Biosystems Engineering
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• 제38권4호
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• pp.255-263
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• 2013

Purpose: It is not easy to drive a rice-transplanter avoiding underlapped or overlapped transplanting in paddy fields. An automated guidance system for the riding-type rice-transplanter would be necessary to operate the rice-transplanter autonomously or to assist the beginning drivers as a driving aid. Methods: A prototype of guidance system was composed of embedded computers, RTK-GPS, and a power-steering mechanism. Two Kalman filters were adopted to overcome sparse positioning data (1 Hz) from the RTK-GPS. A global Kalman filter estimated the posture of rice-transplanter every one second, and a local Kalman filter calculated the posture from every new estimation of the global Kalman filter with an interval of 200 ms. A PID controller was applied to the row-following mode control. A control method of U-turning mode was developed as well. A stepping motor with a reduction gear set was used to rotate the shaft of steering wheel. Results: Test trials for U-turning and row-following modes were done in a paddy field after some parameters have been tuned at the ground speed range of 0.3 ~ 1.2 m/s. The minimum RMS error of offset was 3.13 cm at the ground speed of 0.3 m/s while the maximum RMS error was 13.01 cm at 1.2 m/s. The offset RMS error tended to increase as the ground speed increased. The target point distance, LT also affected the system performance and PID controller parameters should be adjusted on different ground speeds. Conclusions: A target angle-based PID controller plus stationary steering angle controller made it possible for the rice-transplanter to steer autonomously by following a reference line accurately and even on U-turning mode. However, as condition in paddy fields is very complicated, the system should control the ground speed that prevents it from deviating too much due to ditch and slope.

• 전자공학회논문지SC
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• 제40권5호
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• pp.333-340
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• 2003

도플러 처리(Doppler processing) 기능은 잔류(residue) 클러터(clutter)의 제거뿐만 아니라 위상정합누적(coherent integration)을 수행하므로, 펄스 도플러 레이더에 있어서 가장 핵심적인 역할을 수행한다. 디지털 신호처리기(DSP : digital signal processor)의 성능향상과 더불어 DSP를 이용한 구현이 점점 일반화 되어가고 있다. 도플러 처리기가 입력신호를 실시간으로 처리하기 위해서는, 다중 DSP를 이용한 병렬처리 개념이 일반적으로 사용되어야 한다. 본 논문에서는 아날로그 디바이스사의 ADSP21060 8개를 탑재한 Morocco-2 보드를 사용하여 MTI(moving target indicator)필터, 도플러 필터뱅크(DFB : Doppler filter bank) 및 제곱검출기(square-law detector) 등으로 구성된 프로그램 가능한 구조의 도플러 처리기를 구성하였다. 위상정합처리구간(CPI : coherent processing interval) 동안 수신된 입력데이터의 분배(distribution)시간, 출력데이터의 전송(transfer)시간 및 알고리즘 수행에 소요되는 연산시간 등을 수식으로 표현하여, 전체 처리시간과 도플러 처리기 구현에 소요되는 DSP의 수를 예측하였다. 또한 레이더 운용에 필요한 각종 타이밍신호 및 모의 표적신호를 발생할 수 있는 TSG(timing signal generator)를 이용하여 도플러 처리기의 실시간 연산기능을 확인하였다.

• 한국수자원학회논문집
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• 제53권10호
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• pp.889-902
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• 2020

본 연구에서는 GLDAS (Global Land Data Assimilation System)와 GLEAM (Global Land Evaporation Amsterdam Model) 증발산량의 적정성을 평가하기 위해 설마천 유역에서 관측된 에디공분산 기반의 잠열 플럭스를 검증자료로 활용하였다. 잠열 플럭스로부터 증발산량을 산정하기 위해 Koflux 프로그램으로 자료처리하였으며, 자료처리 후 발생된 빈구간을 보충(Gap-filling)하기 위해 FAO-PM (Food and Agriculture Organization-Penman Monteith), 평균 일변동(Mean Diurnal Variation, MDV), 칼만 필터(Kalman Filter)의 3가지 방법으로 대체 증발산량을 산정하였다. 본 연구에서는 3가지 방법 중 칼만 필터(Kalman Filter) 기반의 증발산량이 우수한 Bias와 RMSE를 보여 자료보충 방법으로 채택하였다. 공간증발산량은 GLDAS의 경우 Noah (version 2.1, 3시간, 공간해상도 0.25°)로 추출하였으며 GLEAM의 경우는 GLEAM(version 3.1a, 1일, 공간해상도 0.25°)를 이용하였다. GLDAS와 GLEAM의 공간증발산량을 에디공분산 기반의 증발산량으로 적정성을 평가한 결과, GLDAS의 증발산량이 에디공분산 기반과 비교적 적정한 결과를 나타내었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.544-547
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• 1997

In this paper, we propose a dynamic localization method using a rotating sonar and a map. The proposed method is implemented by using extended Kalman filter. The state equation is based on the encoder propagation model and the encoder error model, and the measurement equation is a map-based measurement equation using a rotating sonar sensor. By utilizing sonar beam characteristics, map-based measurements are updated while AMR is moving continuously. By modeling and estimating systematic errors of a differential encoder, the position is successfully estimated even the interval of the map-based measurement. Monte-Carlo simulation shows that the proposed global position estimator has the performance of a few millimeter order in position error and of a few tenth degrees in heading error and of compensating systematic errors of the differential encoder well.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1896-1900
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• 2003

In this paper, a new type of output feedback control, called a receding horizon finite memory control (RHFMC), is proposed for stochastic discrete-time state space systems. Constraints such as linearity and finite memory structure with respect to an input and an output, and unbiasedness from the optimal state feedback control are required in advance. The proposed RHFMC is chosen to minimize an optimal criterion with these constraints. The RHFMC is obtained in an explicit closed form using the output and input information on the recent time interval. It is shown that the RHFMC consists of a receding horizon control and an FIR filter. The stability of the RHFMC is investigated for stochastic systems.

• 전자공학회논문지B
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• 제30B권12호
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• pp.59-66
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• 1993

In this paper we propose an adaptive update rate tracking algorithm for a phased array radar, based on the interacting multiple model(IMM) algorithm. The purpose of the IMM algorithm hers is twofold: 1) to estimate and predict the target states, and 2) to estimate the level of the process noise. Using the estimate of the process noise level adapted to target dynamics, the update interval is determined to maintain a desired prediction accuracy so that the radar system load is minimized. The adaptive update rate tracking algorithm is implemented for a phased array radar and evaluated with Monte Carlo simulations on various trajectories. The evaluation results of the proposed algorithm and a standard Kalman filter without the adaptive update rate control are presented to compare.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2003년도 춘계학술대회 논문집
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• pp.102-103
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• 2003

최근 고도 경제성장으로 인한 공업화와 그에 따른 업종이 다양해짐에 따라 여기에 수반되어 발생되는 대기오염물질이 증가할 뿐만 아니라 종류도 여러가지로 다양해지고 있다. 대부분 산업공정에서 배출되는 미세먼지 입자는 기존의 집진장치로 거의 포집제거가 불가능하여 대부분이 대기중으로 방출되고 있는 실정이다. 분진 중에서도 입경 l$\mu\textrm{m}$이하의 분진들은 침강 속도가 작아 거의 gas와 동일한 거동을 하기 때문에 기관 또는 폐포에 침착하여 호흡기에 영향을 미치므로 그 발생량과 화학적 성상이 문제화되고 있는 추세이다. (중략)

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1191-1196
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• 2007

This research presents a laboratory study about an annoyance of impulsive sound caused by construction site(breaker and blasting). The sources are sampled from outdoor noise and their levels range from 40 to 75 dB at the interval of 5dB. The noise unit is based on A-weighted sound exposure level (ASEL; $L_{AE}$). To make equal ASEL of outdoor noise, finite impulse response (FIR) filter is applied to the originally sampled source to include the effect of distance attenuation. The evaluation method of jury test adopted a Semantic Difference Method (SDM). In the result of the Jury test for impulsive noise, the annoyance response of blasting noise was higher than that of breaker noise.