• East Asian mathematical journal
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• 제39권1호
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• pp.51-63
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• 2023

We establish the interior L^q regularity estimates for spatial gradient of weak solutions to nonlinear parabolic equations with the inhomogeneity which is given by the divergence and nondivergence data.

• 한국건설관리학회논문집
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• 제12권1호
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• pp.53-61
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• 2011

건축 프로젝트는 그 다양성과 특수성으로 인해 많은 불확실성을 갖고 있다. 이러한 불확실성을 해소하기 위해 공사비 예측은 건축 프로젝트의 전 과정에 걸쳐 반복적으로 이루어져야 하며 특히 초기단계의 공사비 예측은 효과적인 사업 추진을 위해 매우 중요한 과정이다. 통상 초기단계 공사비 예측은 과거에 수행되었던 실적공사와의 비교를 기반으로 하며, 이러한 원리를 이용한 기계학습방법이 사례기반추론이다. 사례기반추론은 해결하고자 하는 문제와 유사한 사례를 데이터베이스에서 검색, 수정하여 해답을 얻는 방법으로 이를 위해서는 속성 유사도와 속성 가중치의 정의가 필요하다. 그러나 속성 가중치를 결정하는 문제에 있어서, 기존의 방법들은 정성변수의 속성 가중치 결정이 불가능하다는 단점이 있으며, 이는 사례기반추론에 사용할 수 있는 변수를 한정시키기 때문에 공사비 예측의 정확성을 저해시키는 요인이 되고 있다. 따라서 본 연구는 최적화 문제를 해결하는 기법의 하나인 유전 알고리즘을 이용하여 정성변수의 속성 가중치 결정 방법을 제안하고, 이를 국방 병영생활관과 공공아파트에 적용하여 그 유효성을 검증하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제15권8호
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• pp.1085-1090
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• 2002

Genetic parameters for birth weights (BWT), calving ease scores observed from calves born by heifers (CEH), and calving ease scores observed from calves born by cows (CEC) were estimated using Bayesian methodology with Gibbs sampling in different threshold animal models. Data consisted of 77,458 records for calving ease scores and birth weights in Gelbvieh cattle. Gibbs samplers were used to obtain the parameters of interest for the categorical traits in two univariate threshold animal models, a bivariate threshold animal model, and a three-trait linear-threshold animal model. Samples of heritabilities and genetic correlations were calculated from the posterior means of dispersion parameters. In a univariate threshold animal model with CEH (model 1), the posterior means of heritabilities for calving ease was 0.35 for direct genetic effects and 0.18 for maternal genetic effects. In the other univariate threshold model with CEC (model 2), the posterior means of heritabilities of CEC was 0.28 for direct genetic effects and 0.18 for maternal genetic effects. In a bivariate threshold model with CEH and CEC (model 3), heritability estimates were similar to those in unvariate threshold models. In this model, genetic correlation between heifer calving ease and cow calving ease was 0.89 and 0.87 for direct genetic effect and maternal genetic effects, respectively. In a three-trait animal model, which contained two categorical traits (CEH and CEC) and one continuous trait (BWT) (model 4), heritability estimates of CEH and CEC for direct (maternal) genetic effects were 0.40 (0.23) and 0.23 (0.13), respectively. In this model, genetic correlation estimates between CEH and CEC were 0.89 and 0.66 for direct genetic effects and maternal effects, respectively. These estimates were greater than estimates between BWT and CEH (0.82 and 0.34) or BWT and CEC (0.85 and 0.26). This result indicates that CEH and CEC should be high correlated rather than estimates between calving ease and birth weight. Genetic correlation estimates between direct genetic effects and maternal effects were -0.29, -0.31 and 0.15 for BWT, CEH and CEC, respectively. Correlation for permanent environmental effects between BWT and CEC was -0.83 in model 4. This study can provide genetic evaluation for calving ease with other continuous traits jointly with assuming that calving ease from first calving was a same trait to calving ease from later parities calving. Further researches for reliability of dispersion parameters would be needed even if the more correlated traits would be concerned in the model, the higher reliability could be obtained, especially on threshold model with property that categorical traits have little information.

• Asian-Australasian Journal of Animal Sciences
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• 제30권11호
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• pp.1550-1556
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• 2017

Objective: This study estimated the genetic parameters for productive and reproductive traits. Methods: The data included production and reproduction records of animals that have calved between 1979 and 2013. The genetic parameters were estimated using multivariate mixed models (DMU) package, fitting univariate and multivariate mixed models with average information restricted maximum likelihood algorithm. Results: The estimates of heritability for milk production traits from the first three lactation records were $0.03{\pm}0.03$ for lactation length (LL), $0.17{\pm}0.04$ for lactation milk yield (LMY), and $0.15{\pm}0.04$ for 305 days milk yield (305-d MY). For reproductive traits the heritability estimates were, $0.09{\pm}0.03$ for days open (DO), $0.11{\pm}0.04$ for calving interval (CI), and $0.47{\pm}0.06$ for age at first calving (AFC). The repeatability estimates for production traits were $0.12{\pm}0.02$, for LL, $0.39{\pm}0.02$ for LMY, and $0.25{\pm}0.02$ for 305-d MY. For reproductive traits the estimates of repeatability were $0.19{\pm}0.02$ for DO, and to $0.23{\pm}0.02$ for CI. The phenotypic correlations between production and reproduction traits ranged from $0.08{\pm}0.04$ for LL and AFC to $0.42{\pm}0.02$ for LL and DO. The genetic correlation among production traits were generally high (>0.7) and between reproductive traits the estimates ranged from $0.06{\pm}0.13$ for AFC and DO to $0.99{\pm}0.01$ between CI and DO. Genetic correlations of productive traits with reproductive traits were ranged from -0.02 to 0.99. Conclusion: The high heritability estimates observed for AFC indicated that reasonable genetic improvement for this trait might be possible through selection. The $h^2$ and r estimates for reproductive traits were slightly different from single versus multi-trait analyses of reproductive traits with production traits. As single-trait method is biased due to selection on milk yield, a multi-trait evaluation of fertility with milk yield is recommended.

• 대한토목학회논문집
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• 제30권5D호
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• pp.453-459
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• 2010

교통안전연구에서 한 지점 (또는 구간)의 기대교통사고건수를 신뢰성 높게 추정하는 것은 매우 중요하다. 기대교통사고건수를 추정하기 위해 현재 국내에서는 주로 관측교통사고건수를 사용하고 있으나 국외에서는 포아송-감마 혼합모형에 기반한 경험적 베이즈 추정치를 활용하고 있는 추세이다. 그간 많은 연구들이 경험적 베이즈 추정치를 이용해 기대교통사고건수 추정 및 교통안전개선사업의 평가를 시도 하였으나 전술한 2가지 추정방법의 추정오차를 비교연구한 문헌은 없는 실정인 바 본 연구는 2가지 추정방법의 추정오차를 모의실험을 통해 비교 분석하여 제시하였다. 모의 발생된 총 3,000,000개 지점의 교통사고 자료를 분석한 결과 기대교통사고건수를 경험적 베이즈 추정방법을 이용해 추정했을 경우 그 추정오차는 관측교통 사고건수만을 이용했을 때 발생하는 추정오차에 비해 항상 작은 것으로 나타나 국내의 교통안전연구 가이드라인에 경험적 베이지안 추정방법의 도입이 필요할 것으로 판단된다. 그러나 사전분포의 불확실성이 높아질수록 두 가지 추정방법의 추정오차의 차이는 감소하는 것으로 나타나, 기대교통사고건수 추정 시 추정된 음이항 모형에 대한 종합적인 검증을 수행한 후 신뢰성 있는 초모수의 추정치를 이용해 경험적 베이지안 방법을 적용하는 것이 바람직하다고 판단된다.

• Journal of Astronomy and Space Sciences
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• 제27권1호
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• pp.21-30
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• 2010

In processing space geodetic data, mapping functions are used to convert the tropospheric signal delay along the zenith direction to the line of sight direction. In this study, we compared three mapping functions by evaluating their effects on the tropospheric signal delay and position estimates in GPS data processing. The three mapping functions tested are Niell Mapping Function (NMF), Vienna Mapping Function 1 (VMF1), and Global Mapping Function (GMF). The tropospheric delay and height estimates from VMF1 and GMF are compared with the ones obtained with NMF. The differences among mapping functions show annual signals with the maximum occurring in February or August. To quantitatively estimate the discrepancies among mapping functions, we calculated the maximum difference and the amplitude using a curve fitting technique. Both the maximum difference and amplitude have high correlations with the latitude of the site. Also, the smallest difference was found around $30^{\circ}N$ and the amplitudes increase toward higher latitudes. In the height estimates, the choice of mapping function did not significantly affect the vertical velocity estimate, and the precision of height estimates was improved at most of the sites when VMF1 or GMF was used instead of NMF.

• 한국수산과학회지
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• 제50권5호
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• pp.594-604
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• 2017

The Korean National Institute of Fisheries Science (NIFS) has biannually (spring and fall, respectively) deployed a bottom trawl survey along the coastal areas for last decade, taking samples on a regular basis (i.e., a systematic sampling). Despite the availability of the survey data, NIFS has not yet officially reported the estimates of the groundfish population sizes as well as has not evaluated uncertainty of the estimates. The objectives of our study were to infer the relative size of a fish population, applying two different sampling techniques (namely simple and stratified sampling) with different observation units to the NIFS survey data, and to compare those two techniques in bias and precision. For demonstration purposes, we used data on Pacific cod (Gadus macrocephalus) collected by the 2011-2015 surveys, and the results of simple and stratified sampling showed that the point estimates and precision varied by observation unit as well as the sampling technique.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2526-2531
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• 2005

A practical pinch torque estimator based on the Kalman filter is proposed for low-cost anti-pinch window control systems. To obtain the accurate angular velocity from Hall-effect sensor measurements, the angular velocity calculation algorithm is executed with additional procedures for removing the measurement noises. Apart from the previous works using the angular velocity estimates and torque estimates for detecting the pinched condition, the torque rate is augmented to the system model and the proposed pinch estimator is derived by applying the steady-state Kalman filter recursion to the model. The motivation of this approach comes from the idea that the bias errors in torque estimates due to the motor parameter uncertainties can be almost eliminated by introducing the torque rate state. For detecting the pinched condition, a systematic way to determine the threshold level of the torque rate estimates is also suggested via the deterministic estimation error analysis. Simulation results are given to certify the pinch detection performance of the proposed algorithm and its robustness against the motor parameter uncertainties.

• 한국정보통신학회논문지
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• 제16권10호
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• pp.2101-2107
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• 2012

하천 및 강등의 유속 측정을 위한 레이다에서는 수면에서 반사 또는 산란되는 전자파로부터 도플러 주파수를 추정함으로서 이에 대응하는 유속 정보를 추출하게 된다. 그러나 수면으로부터 수신되는 전자파 신호들의 도플러 스펙트럼은 측정 환경 및 기상 상태에 따라 매우 다른 형태를 나타낼 수 있다. 따라서 이러한 다양한 도플러 스펙트럼들의 존재로 인하여 레이다 센서에서의 유속정보 추출 알고리즘의 정확도 및 신뢰성에 심각한 문제가 발생할 수 있다. 따라서 본 논문에서는 수면으로부터 수신되는 매우 다양한 도플러 신호 스펙트럼을 적절하게 모의 구현할 수 있는 도플러 스펙트럼 모델을 제안하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제15권12호
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• pp.1690-1694
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• 2002

Genetic parameters were estimated for birth weight and weaning weight from three year (1991-1993) data totalling 1100 records of 25 rams to 205 ewes of Indigenous Sabi flock maintained at Grasslands Research Station in Zimbabwe. AIREML procedures were used fitting an Animal Model. The statistical model included the fixed effects of year of lambing, sex of lamb, birth type and the random effect of ewe. Weight of ewe when first joined with ram was included as a covariate. Direct heritability estimates of 0.27 and 0.38, and maternal heritability estimates of 0.24 and 0.09, were obtained for birth weight and weaning weight, respectively. The total heritability estimates were 0.69 and 0.77 for birth weight and weaning weight, respectively. Direct-aternal genetic correlations were high and positive. The corresponding genetic covariance estimates between direct and maternal effects were positive and low, 0.25 and 0.18 for birth weight and weaning weight, respectively. Responses to selection were 0.8 kg and 0.14 kg for birth weight and weaning weight, respectively. The estimated expected correlated response to selection for birth weight by directly selecting for weaning weight was 0.26. Direct heritabilities were moderate; as a result selection for any of these traits should be successful. Maternal heritabilities were low for weaning weight and should have less effect on selection response. Indirect selection can give lower response than direct selection.