• Journal of the Society of Naval Architects of Korea
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• v.29 no.2
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• pp.92-102
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• 1992

Prediction of energy absorption for bow structure is important for a design of protective structures against collision. For the crushing behaviour of basic element of energy absorption, the plastic mechanism method is applied. The ship's crushing strength of bow section is obtained by summing the energy dissipated in all individual elements. The theoretical predictions are compared with experimental results for ship's bow models published with experimental results for ship's bow models published in the references, and it is observed that the present prediction method of crushing strength correlates well with the experimental results.

• The Korean Journal of Applied Statistics
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• v.36 no.6
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• pp.529-545
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• 2023

This paper introduces the Banded-VHAR model suitable for high-dimensional long-memory time series with band structure. The Banded-VHAR model has nonignorable correlations only with adjacent dimensions due to data features, for example, geographical information. Row-wise estimation method is adapted for fast computation. Also, two estimation methods, namely BIC and ratio methods, are proposed to estimate the width of band. We demonstrate asymptotic consistency of our proposed estimation methods through simulation study. Real data applications to pm2.5 and apartment trading volume substantiate that our Banded-VHAR model outperforms traditional sparse VHAR model in forecasting and easy to interpret model coefficients.

• Korean Journal of Poultry Science
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• v.17 no.4
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• pp.243-254
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• 1990

This study was carried out to investigate the effectiveness of the selection for commercial populations of layer chickens subjected to multiple objectives. For that purpose, predicted selection responses obtained from estimated genetic parameters and observed values were compared. Data for two layer pure lines, Line-w(Single Comb White Leghorn) and Line-B (brown layer) which have been maintained at the Mani Breeding Farm were collected from 1980 to 1985 during 5 generations. The annual genetic gains were estimated by the moth of selection index in retrospect on the basis of selection differentials, phenotypic and genetic variance-covariance for the traits considered. SM was found to be shorten by 1.67 days and 1.14 days per generation in Line-W and Line-B. EN300 and EN400 were found to be increased by 4.15 and 5.92 per generation in Line-W and 257 and 3.73 per generation in Line-B. The annual gains realized were found to be significantly different from expected gains predicted on the basis of the annual selection differentials and genetic parameters in later generations, but it could not be concluded that the differences were attributed to genetic effects.

• Journal of Embryo Transfer
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• v.29 no.3
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• pp.289-296
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• 2014

The pedigree information and race records of 1,000 m finishing time of Jeju race horses at KRA were used to study the effect of amount of pedigree information and parental misidentification on the estimates of genetic parameters. The modified data sets were made at the range of 2.5 to 25% parental misidentifications or loss of parental information of individuals with an increment of 2.5 percent. For each incremental level, 20 randomly replicated data sets were obtained and analyzed by single-trait analysis with a DF-REML(AI) algorithm. As the rate of misidentification increased or the amount of pedigree information decreased, the estimates of fraction of additive genetics variance component gradually decreased almost linearly (p<0.05), while the estimated fractions of error variance and permanent environmental variance components gradually increased for the finishing time. Regression coefficients of the percentage amount of both parents' information loss and incorrect pedigree information on additive genetic variances were -0.079 and -0.114, respectively (p<0.01). The estimate of heritability decreased by 0.92% for one percent loss of both parents' information and 1.39% for one percent increase of both parental misidentifications of progeny (p<0.01). For the consideration of probable incorrect and missing parent information of progeny in this early population of Jeju horses, the estimates of additive genetic parameters would be biased downward about ten percent. This results indicate that the amount of pedigree information loss and misidentification of progeny would severely affect estimates of genetic parameters and would reduce genetic gains for selection in Jeju horse population.

• Journal of the Korea Computer Industry Society
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• v.5 no.4
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• pp.471-480
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• 2004

A estimating capability of software effort, duration and cost is based on accurate size estimate of the software to be developed. A simplified function point (FP) approach to software size estimation is described, which first skip the computation step for value adjustment factor, thus directly obtaining final adjusted FP from unadjusted FP. The research seeks suitable models based on statistical regression models in the context of case study based on 783 software projects. The approach also are built for subsets of projects using new development, enhancement and re-development types.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2008.12a
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• pp.139-145
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• 2008

1) 밭 토양의 질소공급능력은 밭작물 양분요구량의 1.2배였고, 논토양에서는 1.02로, 평균 1.11이었다. 2) 밭 토양에서 Ca, K 함량은 CNCs보다 낮았고, TN, Mg 함량은 CNCs보다 높았다. 논토양에서는 Ca, Mg, K는 CNCs보다 낮아서 양분의 불균형을 이루고 있다. 3) 작물생산량 중의 조사료 생산비율은 68.1%였다. 4) 조농비는 41:59(조사료 자급비율 91.4%) 5) 토양으로의 가축분뇨 질소환원 가능량은 1,034kg(발생 질소량의 60%)로 추정되었다. 6) 토양으로부터 작물로의 질소공급량은 토양 질소량의 72.4%인 1,383.3kg N으로 추정되었고, 천연양분공급량은 298.6 kg N, 잔류양분 287.7 kg N으로 추정되었다. 7) 토양-작물-가축간의 물질수지는 거의 균형을 이루고 있다고 판단되지만, 토양진단을 통한 양분불균형의 개선이 필요하고, 벼 재배 후 월동 사료작물 재배면적의 확대로 조사료 자급 율을 높이므로, 조농비의 개선이 필요 8) 특히 논 토양의 유박비료 시용량을 가축분뇨로 전량 대체하는 것이 경지 내에서의 물질순환 유지에 필요하다고 판단된다.

• Magazine of the Korean Society of Agricultural Engineers
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• v.48 no.2
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• pp.15-23
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• 2006

우리나라의 수량과 수질의 관리를 위해서는 상류와 하류의 유출 상황을 파악하는 것이 가장 중요하다. 어느 임의 지점의 유출량은 생활용수, 공업용수, 농업용수 등 유역 상류의 각종 용수의 수요가 반영돼 나타난 결과라고 할 수 있다. 이 중에서 농업용수의 변화는 생활용수, 공업용수에 비해 변화폭이 크고 다양하게 나타난다. 그러나 현재 사용되고 있는 대다수의 유출모형은 용수수요를 고려하지 못하고 있는 상태이다. 우리나라의 유역에서 논이 차지하는 비중은 전국토의 11% 정도에 이르며, 논의 저류능력을 고려할 때 농업용수가 유출에 미치는 영향은 매우 크다고 할 수 있다. 따라서 농업용수 수요량을 다양하고 쉽게 추정할 수 있는 프로그램을 개발, 이용하여 농업용수 수요량을 추정하여 유출 모의에 적용함으로써 보다 현상에 적합한 유출량을 생산하는 것이 중요하다. 따라서, 본고에서는 하천 상류와 하류의 유출량 모의를 위해 사용될 농업용수 수요량을 손쉽게 추정할 수 있도록 개발된 WARES(WAter Requirements Estimating System)에 대해 소개하고자 한다.

• Journal of the Korean Data and Information Science Society
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• v.20 no.3
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• pp.485-492
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• 2009

In this paper, we studied process capability analysis for brake-pad manufacturing system and considered Weibull, normal and logistic distributions for density estimation of wear life of brake pads for a passenger car with a real data. These three distributions are seem to work well. Estimated percentiles of brake pads can be used to evaluate the design criteria and customers' need for brake pads.

• The Journal of the Korea Contents Association
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• v.11 no.1
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• pp.329-339
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• 2011

This study aims at investigating how English proficiency affects economic development of a country by analyzing the relationships among English proficiency, economic activities (amount of trade, R&D investment, etc), and the rate of economic growth, focusing on twenty-one non-English-speaking OECD countries. Ordinary Least Square (OLS) and Seemingly Unrelated Regression Estimation (SURE) were used for the data analysis in the study. The findings reveals that there existed little statistical significance to support the fact that English proficiency was directly related to the economic development in a positive way in many countries except Mexico, the Czech Republic, Finland, and Poland. However, English proficiency indirectly influenced the economic development in the way of increasing the amount of trade. These results can lead to the conclusion that English proficiency is not a sufficient element but a necessary one. Furthermore, it is expected that English proficiency can positively affect the economic development when it plays a part as sufficient complementary goods which make up for physical capital, technology accumulation, political stability, and worthy government.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.4
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• pp.1-9
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• 2003

Many CDMA systems provide pilot channels in order to help channel estimation process. Especially in wideband CDMA systems, the number of receive diversity paths can be large due to small chip duration and high multi-path resolution capability. Hence, the received signal power of each path is small for a given total SNR (signal-to-noise ratio) and the pilot power of each path may not be sufficiently large for accurate channel estimation. When the pilot power is small, one can use decision-directed channel estimation to utilize more energy of the received data. However, the decision errors can deteriorate the quality of decision-directed channel estimation. This paper proposes a novel channel estimation method that optimally utilizes receiver decisions as well as pilot symbols with the help of estimated SER (symbol error rate) and SNR. The proposed method computes two channel estimates using the pilot and the data channel filters and optimally combines them. The simulation results show that the proposed method is robust and outperforms the conventional pilot-symbol-aided channel estimation method.