• 한국수산과학회지
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• 제41권6호
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• pp.485-492
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• 2008

To propose proper vessel characteristics for sustainable fisheries in Korean waters, we analyzed the fishing capacity, scale efficiency and utilization of large pair-trawl vessels based on the database of catch, effort and vessel characteristics (gross tonnage and engine power) in 1990 by applying data envelopment analysis (DEA). The input factors were gross tonnage, horse power and days operated; whereas the output factor was expected catch by vessel characteristics. The optimal vessel types, selected based on the input-oriented technical efficiency and gross tonnages, was 100 GT with engine power <600 HP. The output-oriented unbiased estimate of capacity utilization (CD) decreased with increasing vessel tonnage. For the same tonnage vessels, the CD decreased with increasing engine power.

• Asian-Australasian Journal of Animal Sciences
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• 제15권11호
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• pp.1536-1542
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• 2002

The genetic variability of three poultry breeds namely Aseel, Miri and Nicobari taken from different geographical locations of India were evaluated using 15 microsatellite loci. No. of alleles varied from 3 to 9 in Aseel, 3 to 8 in Miri and 2 to 7 in Nicobari. Mean PIC values in Aseel, Miri and Nicobari breeds were 0.64, 0.66 and 0.63, respectively. Average unbiased heterozygosity and direct count heterozygosity were 0.65 and 0.59, 0.68 and 0.61, and 0.64 and 0.57 in Aseel, Miri and Nicobari breeds, respectively. High heterozygosity values revealed in this study are indicative of low level of inbreeding, large population size and no or low selection pressure for commercial trait in all three populations. The estimate of genetic distances using Nei's standard, Nei's minimum and Reynold's distance revealed Aseel and Nicobari to be more closely related than Miri breed of poultry.

• 응용통계연구
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• 제23권2호
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• pp.263-274
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• 2010

기업경기실사지수는 기업의 지난 실적과 기업가의 계획이나 판단 등을 기초로 하여 만들어지는 대표적인 경기 전망 지수이다. 이 지수는 경제 현장에서 널리 사용됨에도 불구하고 아직까지 규명된 통계적 성질은 많지 않다. 본 논문에서는 기업경기실사지수에 대한 통계적 성질을 고찰한다. 유한모집단에서 모집단 기업경기실사지수를 정의하고 단순확률표집을 가정한 후 모집단 기업경기실사지수 추정량을 구하며, 기업경기실사지수의 기댓값, 분산, 비편향 분산 추정량, 신뢰구간, 상대표준오차를 구한다. 그리고 기업경기실사지수의 평가지표로서 상대표준오차보다는 신뢰구간이 더 합리적임을 언급한다.

• Communications for Statistical Applications and Methods
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• 제27권3호
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• pp.349-363
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• 2020

Penalized spline is a suitable nonparametric approach in estimating mean model in small area. However, application of the approach in informative sampling in a published article is uncommon. We propose a semiparametric mixed-model using penalized spline under informative sampling to estimate mean of small area. The response variable is explained in terms of mean model, informative sample effect, area random effect and unit error. We approach the mean model by penalized spline and utilize a penalized spline function of the inclusion probability to account for the informative sample effect. We determine the best and unbiased estimators for coefficient model and derive the restricted maximum likelihood estimators for the variance components. A simulation study shows a decrease in the average absolute bias produced by the proposed model. A decrease in the root mean square error also occurred except in some quadratic cases. The use of linear and quadratic penalized spline to approach the function of the inclusion probability provides no significant difference distribution of root mean square error, except for few smaller samples.

• Asian-Australasian Journal of Animal Sciences
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• 제21권6호
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• pp.769-775
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• 2008

This study was on the relative net income (RNI) for 18,286 Iranian Holstein cows from 799 herds, with first freshening between 1991 and 2000. Two kinds of production system, which differed mainly in milk pricing system and feed cost, were considered. Four different models adopted from the literature were examined to find the optimum model. They differed by the cost of rearing and growth after first calving and they needed different amounts of economic data at the farm level. Results showed that four measures of RNI were highly correlated (>0.96) and could be used equally to measure lifetime profitability of cows. Therefore, in herds without a regular system for recording economic and management data, use of the simplest model is recommended. Multiple regression analysis revealed that RNI was affected by age at first freshening, milk yield and days of productive life (DPL), regardless of production system, and a similar breeding goal could be defined for the two systems. Multiple regression analysis of RNI showed that in order to obtain an unbiased estimate of economic value for DPL, the per day milk yield, not total lifetime milk yield, should be included in the regression model along with DPL. Regression analysis suggested that it is possible to predict RNI using information on age at first freshening along with the length of first lactation and per day milk yield with a coefficient of determination ranging from 0.44 to 0.47.

• 한국농공학회지
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• 제41권5호
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• pp.53-67
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• 1999

In this study, regional frequency analysis is used to determine each subbasin drought frequency with watershed runoff which is calculated with Tank Model in Nakdong river basin. L-Monments methd which is almost unbiased and nearly normal distribution is applied to estimate paramers of drought frequency analysis of monthly runoff time series. The duration of '76-77 was the most severe drought year than othe rwater years in this study. To decide drought frequency of each subbasin from the main basin, it is calculated by interpolaing runoff from the frequency-druoght runoff relationship. and the linear regression analysis is accomplished between drought frequency of main basin and that of each subbasin. With the results of linear regression analysis, the drought runoff of each subbasin is calculated corresponing to drought frequency 10,20 and 30 years of Nakdong river basin considering safety standards for the design of impounding facilities. As the results of this study, the proposed methodology and procedure of this study can be applied to water budget analysis considering safety standards for the design of impounding facilities in the large-scale river basin. For this purpose, above all, it is recommanded that expansion of reliable observed runoff data is necessary instead of calculated runoff by rainfall-runoff conceptual model.

• 대기
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• 제28권3호
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• pp.273-289
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• 2018

This paper evaluates daily precipitation products from Integrated Multisatellite Retrievals for Global Precipitation Measurement (IMERG), Tropical Rainfall Measuring Mission Multisatellite (TRMM) Precipitation Analysis (TMPA), and the Climate Prediction Center Morphing Method (CMORPH), validated against gauge observation over South Korea and gauge-based analysis data East Asia during one year from June 2014 to May 2015. It is found that the three products effectively capture the seasonal variation of mean precipitation with relatively good correlation from spring to fall. Among them, IMERG and TMPA show quite similar precipitation characteristics but overall underestimation is found from all precipitation products during winter compared with observation. IMERG shows reliably high performance in precipitation for all seasons, showing the most unbiased and accurate precipitation estimation. However, it is also noticed that IMERG reveals overestimated precipitation for heavier precipitation thresholds. This assessment work suggests the validity of the IMERG product for not only seasonal precipitation but also daily precipitation, which has the potential to be used as reference precipitation data.

• 문화기술의 융합
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• 제6권4호
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• pp.575-582
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• 2020

본 연구는 인터넷 뉴스 댓글 빅데이터 분석을 통해 뉴스 댓글 사용자의 정치적 성향을 추정하는 방법을 제안한다. 인터넷 뉴스 댓글과 작성자의 정치 성향을 함께 제공하여 디지털 매체를 통한 정보 전달의 객관성과 중립성을 확보하고자 한다. 250만 건 이상의 인터넷 뉴스 댓글의 특성을 분석하고 사용자의 정치적 성향을 효과적으로 추정하기 위한 특징을 추출한다. 어휘사전 기반 알고리즘과 유사도 기반 알고리즘을 제안하고 실험을 통해 두 알고리즘을 비교하고 효과를 검증한다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2010년도 학술발표회
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• pp.1400-1404
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• 2010

본 연구에서는 현재 시행되고 있는 오염총량관리제 모니터링 시스템에 적용가능한 부하량 추정기법에 대하여 제시하였다. 수정 TANK 모형을 통하여 8일 간격 유량자료의 1일 간격 유량자료로 의 확장을 시행하였다. 그리고 최소분산 비편향 추정기법을 통한 7변수 대수 선형 모형으로 오염 부하량을 추정하였다. 그 결과 TOC 및 BOD 부하량 추정에서 만족스러운 결과를 확인할 수 있었다. 연구의 적용의 일환으로, 낙동강유역의 TOC 및 BOD 항목의 부하량 유황 곡선을 작성하여 전체적인 분포를 살펴보았다.

• 천문학회보
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• 제44권1호
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• pp.78.1-78.1
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• 2019

Using a method to correct redshift space distortion (RSD) for individual galaxies, we mapped the real space distributions of galaxies in the Sloan Digital Sky Survey (SDSS) Data Release 7(DR7). We use an ensemble of mock catalogs to demonstrate the reliability of this extension, showing that it allows for an accurate recovery of the real-space correlation functions and galaxy biases. We also demonstrate that, using an iterative method applied to intermediate scale clustering data, we can obtain an unbiased estimate of the growth rate of structure $f\sigma_8$, which is related to the clustering amplitude of matter, to an accuracy of $\sim 10\%$. Applying this method to the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7), we construct a real-space galaxy catalog spanning the redshift range $0.01 \leq z \leq 0.2$, which contains 584,473 galaxies in the North Galactic Cap (NGC). Using this data we, infer $0.376 \pm 0.038$ at a median redshift z=0.1, which is consistent with the WMAP9 cosmology at $1\sigma$ level. By combining this measurement with the real-space clustering of galaxies and with galaxy-galaxy weak lensing measurements for the same sets of galaxies, we are able to break the degeneracy between $f$, $\sigma_8$ and $b$. From the SDSS DR7 data alone, we obtain the following cosmological constraints at redshift $z=0.1$ for galaxies.