• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.2
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• pp.149-160
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• 2015

This study aims to estimate the forest volumes of the upper region of Nam-Han River in ecosystem zoning by forest types and age classes, and to suggest the optimal estimation method through the comparison of the standard errors according to the spatial unit. In the estimation of forest volumes, we used both of direct estimation, which uses sample plots of the target area only, and synthetic estimation, which includes sample plots of the expanded areas as well as those of the target area. As for the spatial expansion, we applied four standards for synthetic estimator: Mountainous zone, Neighbor ecosystem region, Gangwon province, and Buffer zone. The results show that average forest volume per ha, calculated by direct estimation, was $143.5m^3/ha$, while that by synthetic estimation with each standard, was estimated at $146.9m^3/ha$ by Gangwon province, $144.8m^3/ha$ by Buffer zone, $139.8m^3/ha$ by Neighbor ecosystem region, and $138.6m^3/ha$ by Mountainous zone, respectively. The standard errors of direct estimation was $1.79m^3/ha$, while those of synthetic estimation showed not a great difference among the errors. Meanwhile, considering the standard errors by forest type, the lowest was ${\pm}2.3m^3/ha$ of broad-leaved forest, followed by ${\pm}3.3m^3/ha$ of mixed forest, and ${\pm}4.8m^3/ha$ of coniferous forest.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.10
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• pp.2303-2309
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• 1997

This paper presents a convergence analysis of the stocastic gradient adaptive algorithm based on the least mean absolute third (LMAT) error criteriohn. Under the assumption that the signals involved are zero-mean, wide-sense sateionaryand gaussian, a set of nonlinear difference equations that characterizes the mean and mean-squared behavior of the algorithm is derived. Computer simulation resutls show fairly good agreements between the theoetical and empirical behaviors of the algorithm.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.3
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• pp.266-273
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• 2007

The change patterns of the water quanity, water quality(WQ, exclusively COD in this study) and monthly / annual pollutant loads(PL) estimated using the daily effluent discharges and WQ measurement data are analyzed in the Nakdong river estuarine seadike. The contribution factor defined by the ratio of the water quantity range and WQ range shows that the PL pattern in this estuary is classified as the strongly flow(water quantity)-dominated situation. The estimated PL(EPL)s with respect to the increasing sampling periods, e.g., 2-days, 5-days, 7-days, and so on, show that the mean values of the EPLs remain nearly same, whereas the standard deviations of the EPLs have an obvious increasing trend. The PL values using the monthly-averaged water quantity and WQ measurement data could have approximately 100% estimation error in annual mean and $300\sim400%$ estimation errors in summer season because its confidence level is relatively low. It is recommended that the PL should be estimated using at least $10\sim20$ day interval data sets and also the water quantity(river discharges) and WQ should be measured at the intervals of at least 1 day interval and 5 to 7 days, respectively in summer.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.3
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• pp.28-39
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• 2010

In this paper, a new method to estimate MU (motor unit) location in the short head of BIC (biceps brachii) muscle using surface EMG (electromyogram) is proposed. The SMUAP (single motor unit action potential) is generated from a MU located at certain depth from the skin surface. The depth is referred as MU location. For estimating muscle force precisely, the information of the MU location is required. The reference SMUAPs are simulated based on anatomical structure of human muscle, and compared with acquired real EMG signals using 3-channel surface EMG electrode. The proposed method was compared with the results of previous researchers and verified its accuracy by computer simulation. From the simulation result in case of the MU located in 8[mm], the average estimation error of proposed method was 0.01[mm]. But the average estimation error of Roeleveld's method was 2.33[mm] and Akazawa's method was 1.70[mm]. Therefore the proposed method was more accurate than the methods of previous researchers.

• Journal of the Korean Regional Science Association
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• v.33 no.3
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• pp.3-19
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• 2017

The purpose of this paper is to analyze the impacts of regional industrial diversity on regional business cycle response to national volatility. We employed mean group and pooled mean group estimators of panel vector error-correction models in order to control unobserved heterogeneity of the port cities, such as Pusan, Ulsan and Incheon. The results show that in various industrial regions, short-term fluctuations in the unemployment rate are small compared to other regions. On the contrary, long-term volatility of manufacturing production index is low in those regions.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.408-408
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• 2011

수자원관리와 수문모형에 있어 강수, 증발산, 침투, 침루 등의 물 순환과정에 대한 실질적인 이해와 분석연구의 중요도가 높아지고 있는 실정이며, 그중에서도 토양수분은 강수의 침투, 유출 등의 지표면과 대기사이의 질량 및 에너지이동에 관여하는 중요한 요소로서 수자원 및 수문현상에 직접적인 영향을 미친다. 이를 위해 강수, 증발산, 토양수분과 같은 수문변수에 대한 다양한 관측이 실시되어야 하지만 국내에서는 지속적이고 안정적으로 지상관측을 할 수 없는 실정이며 관련 기반기술도 매우 취약하다. 따라서 이를 극복하기 위해서는 위성영상자료를 이용함으로써 한반도 전체에 대한 광역적인 토양수분자료의 획득을 용이하게 한다. 본 연구의 연구유역은 수자원 연구를 위해서 지정된 용담댐 시험유역으로 하였으며, 토양수분 관측지점의 지상관측 수문자료인 각 지점별 강수량, 지면온도, 인공위성자료인 MODIS 정규식생지수 등의 가용자료를 수집하고 신경망모형을 활용한 토양수분자료 생산 모형을 개발하여, 개선된 시공간 분해능과 공간정보 대표성을 가진 광역 토양수분자료를 생산하고 적용타당성을 분석하였다. 산정된 토양수분모형의 적용가능성을 파악하고자 용담댐 유역의 각 지점별 토양수분 관측데이터와 추정데이터를 비교한 결과 추천, 부귀, 상정 지점의 경우 평균 약 0.9257의 상관계수와 약 1.2917의 평균제곱근오차를 보였고, 검증지점인 천천2의 경우 약 0.8982의 상관계수와 약 5.1361의 평균제곱근오차의 결과를 보여주었으며 토양수분 추정모형의 적용가능성이 높음을 확인할 수 있었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.05a
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• pp.553-555
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• 2021

빈혈의 유병률은 매년 증가하고 있으나 이를 가벼운 질병으로 인식해 치료 시기를 놓치는 환자들이 존재한다. 빈혈의 발생원인으로 혈액 내 헤모글로빈 및 헤모글로빈 내 철 부족이 있으며, 헤모글로빈 측정기술의 경우 채혈 이외에 사람의 신체 및 건강 정보를 적용한 사례는 찾아보기 어렵다. 본 논문에서는 신체(키, 몸무게 및 허리둘레) 및 건강 정보(혈청지오티, 이완기 혈압 및 감마지티피 등)가 포함된 건강검진 빅데이터를 이용하여 단일 특징에 대해 선형회귀분석을 수행하고, 다중 특징에 대해 다중회귀분석을 수행하여 회귀분석 식을 산출, 산출된 회귀분석 식을 통해 헤모글로빈을 추정하여 실제 헤모글로빈값과 오차율을 계산하고 비교한다. 실험 결과, 선형회귀분석 식을 통해 헤모글로빈을 추정하였을 때 평균 8.124%의 오차율이 계산되었으며, 다중회귀분석의 경우 선형회귀분석보다 낮은 6.767%의 오차율이 계산되었다.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.363-370
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• 2022

In this paper, an estimation algorithm for state of charge (SOC) was applied using an equivalent circuit model (ECM) and an Extended Kalman Filter (EKF) to improve the estimation accuracy of the battery system states. In particular, an observer was designed to estimate SOC along with the aged capacity. In the case of the fresh battery, when SOC was estimated by Kalman Filter (KF), the mean absolute percentage error (MAPE) was 0.27% which was smaller than MAPE of 1.43% when the SOC was calculated by the model without the observer. In the driving mode of the vehicle, the general KF or EKF algorithm cannot be used to estimate both SOC and capacity. Considering that the battery aging does not occur in a short period of time, a strategy of periodically estimating the battery capacity during charging was proposed. In the charging mode, since the current is fixed at some intervals, a strategy for estimating the capacity along with the SOC in this situation was suggested. When the current was fixed, MAPE of SOC estimation was 0.54%, and the MAPE of capacity estimation was 2.24%. Since the current is fixed when charging, it is feasible to estimate the battery capacity and SOC simultaneously using the general EKF. This method can be used to periodically perform battery capacity correction when charging the battery. When driving, the SOC can be estimated using EKF with the corrected capacity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8C
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• pp.627-632
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• 2008

The timing offset is one of the main error sources in estimating the frequency offset in orthogonal frequency division multiplexing (OFDM) systems. Although some works have been done to mitigate the influence of the timing offset on the frequency offset estimation, most of the investigations require the knowledge of the timing offset range, which is not generally available in practical systems. In this paper, we propose a new frequency offset estimation scheme using differential combining between two successive correlation samples, which does not require the knowledge of the timing offset range, and thus, is robust to the timing offset variation. The simulation results show that the proposed scheme is not only robust to the timing offset variation, but also generally performs better than the conventional scheme on the average, in the case of the timing offset range being not known exactly.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.2
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• pp.10-20
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• 2012

This study shows how to estimate AADT(Annual Average Daily Traffic) on temporary count data using new grouping method. This study deals with clustering permanent traffic counts using monthly adjustment factor, daily adjustment factor and a percentage of hourly volume. This study uses a percentage of hourly volume comparing with other studies. Cluster analysis is used and 5 groups is suitable. First, make average of monthly adjustment factor, average of daily adjustment factor, a percentage of hourly volume for each group. Next estimate AADT using 24 hour volume(not holiday) and two adjustment factors. Goodness of fit test is used to find what groups are applicable. MAPE(Mean Absolute Percentage Error) is 8.7% in this method. It is under 1.5% comparing with other method(using adjustment factors in same section). This method is better than other studies because it can apply all temporary counts data.