• The Korean Journal of Applied Statistics
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• v.14 no.2
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• pp.233-243
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• 2001

중장기 수요예측을 위해 자주 사용되는 방법으로 확산모형과 성장곡선모형을 들 수 있다. 본 논문에서는 이들 방법론의 성격 및 실제 적용에 있어 모수추정에 따른 문제점들을 살펴보고, 모수추정을 효율적으로 수행하기 위한 전략을 제시한다. 또한 실제 자료에 각 방법론들을 적용하여 예측결과를 비교한다.

• Journal of Animal Science and Technology
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• v.49 no.2
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• pp.195-202
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• 2007

The growth traits in swine are economically important, which are measured by gain in weight during test period or by age of days to certain weight. However, the difference in growth rate due to individual performance and also other factors occurs. The more reasonable estimation of the measurements of these traits provides the less error in genetic evaluation of pigs. The data from 1,576 heads being weighed periodically of Gyungnam-heugdon(Berkshire) were analyzed to estimate the growth curve which is used to decide average daily gain and days to 90kg. It may not be possible to directly compare accuracy between the conventional methods and the alternative methods. However, the alternative methods by growth curve would be superior to the conventional methods not only in theoretical background, but also in acceptability for diverse factors such as breed, sex and age. The theoretical superiority of the alternative methods comes from estimation at same age in daily gain and calculation of additional days from measuring date to days to 90kg by growth curve of individual. Also this can be easily adopted in a computer system according to breed and sex.

• Annual Conference of KIPS
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• 2005.11a
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• pp.345-348
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• 2005

소프트웨어 개발 후 인도 전 테스트 단계중에 발생되는 테스트 노력 소요량을 고려한 소프트웨어 신뢰도 성장 모델을 제시하여 테스트 노력소요량 동태를 시간함수인 로지스틱 곡선으로 설명한다. 테스트 단계중에 소요되는 테스트노력의 양에 대한 결함 검출비를 현재의 결함 내용에 비례하는 것으로 가정하여 소프트웨어 신뢰도 성장 모델을 비동차 포아송 프로세스(NHPP)로 공식화하여, 이 모델을 이용하여 소프트웨어 신뢰도 척도에 대한 데이터 분석기법을 개발한다. 그간 여러 문헌에서 소프트웨어 신뢰도 향상 모델을 연구할 때 소프트웨어 테스트 중에 소요되는 테스트노력의 양으로서 지수함수 곡선, 레일레이 곡선, 웨이불 곡선을 사용해 왔다. 그러나, 모든 소프트웨어 개발 환경에서 지금까지 제시된 그러한 곡선중 하나에 의해서 테스트노력 소요 곡선을 표현하는 것은 적절하지 못하다는 것이 밝혀지고 있다. 본 논문에서는 로지스틱 테스트노력 곡선이 소프트웨어의 개발/테스트 노력곡선으로 적절하게 표현될 수 있다는 것과 실제 데이터를 근거로 하여 적용하여서 예측성이 매우 좋은 능력을 가지고 있다는 것을 보이고자 한다.

• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.229-237
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• 2022

This study investigated the growth characteristics of four strains of newly developed synthetic Korean native commercial chickens (KNCs). We investigated a suitable growth curve model in KNCs and estimated the number of days to reach a 2 kg market weight. Body weight was measured at 2-week intervals from birth to 12 weeks of age. The growth curves were estimated using von Berteralanffy, Gompertz, and logistic functions. The results showed that males were significantly heavier than females at all ages, but there were no significant differences in body weight between strains, except at birth and 2 and 6 weeks of age. The coefficients of determination and adjusted determination of growth function had high goodness-of-fit (97.4~99.7). Of the growth curve parameters, the mature weight and growth ratio were higher in males than in females, but the maturity rate was similar in males and females. The inflection point occurred at approximately 7 weeks of age for females and 8 to 9 weeks of age for males. The weights estimated from the growth curve functions almost agreed with the actual weights, except for male weights estimated using the von Bertalanffy function. The coefficients of determination of the regression equations for weight to age were 0.9583 to 0.9746. The 8- and 10-week-old body weights estimated using the regression equation, and the 12-week-old weight estimated using the logistic function were most similar to the actual weight. Using these models, the estimated age of KNCs to reach 2 kg was 62.0~64.6 days for males and 74.9~78.6 days for females.

• Journal of Animal Science and Technology
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• v.48 no.1
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• pp.29-38
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• 2006

The objective of this study was to estimate genetic variances of growth curve parameters in Hanwoo cows. The data used in this study were records from 1,083 Hanwoo cows raised at Hanwoo Experiment Station, National Livestock Research Institute(NLRI). First evaluation model(Model I) fit year-season of birth and age of dam as fixed effects and second model(Model II) added age at the final weight as a linear covariate to Model I. Heritability estimates of A, b and k from Gompertz model were 0.22, 0.11 and 0.07 using modelⅠ and 0.28, 0.11 and 0.12 using modelⅡ. Those from Von Bertalanffy model were 0.22, 0.11 and 0.07 using modelⅠ, 0.28, 0.11 and 0.12 using modelⅡ. Heritability estimates of A, b and k from Logistic model were 0.14, 0.07 and 0.05 using modelⅠ, 0.18, 0.07 and 0.12 using modelⅡ. Heritability estimates of A from Gompertz model were higher than those from Von Bertalanffy model or Logistic model in both model Ⅰand model Ⅱ. Heritability estimates of b from Logistic model were higher than those from Gompertz model or Von Bertalanffy model in both modelⅠand model Ⅱ. Heritability estimates of birth weight, weaning weight, 3 month weight, 6 month weight, 9 month weight, 12 month weight, 18 month weight, 24 month weight, 36 month weight were after linear age adjustment 0.27, 0.11, 0.19, 0.14, 0.16, 0.23, 0.52 and 0.32, respectively. Heritability estimates of birth weight, weaning weight, 3 month weight, 6 month weight, 9 month weight and 24 month weight fit by Gompertz model were larger than those estimated from linearly adjusted data. Heritability estimates of 12 month weight, 18 month weight and 36 month weight fit by Von Bertalanffy model were larger than those estimated from linearly adjusted data. In the multitrait analyses for parameters from Gompertz model, genetic and phenotypic correlations between A and k parameters were －0.47 and －0.67 using modelⅠand －0.56 and －0.63 using model Ⅱ. Those between the A and b parameters were 0.69 and 0.34 using modelⅠand 0.72 and 0.37 using model Ⅱ. Those between the b and k parameters were －0.26 and 0.01 using modelⅠand －0.30 and 0.01 using model Ⅱ. In the multitrait analyses for parameters from Von Bertalanffy model, genetic and phenotypic correlations between A and k parameters were －0.49 and －0.67 suing model Ⅰ and －0.57 and －0.70 using modelⅡ. Those between the A and b parameters were 0.61 and 0.33 using modelⅠ and 0.60 and 0.30 using model Ⅱ. Those between the b and k parameters were －0.20 and 0.02 using modelⅠ and 0.16 and 0.00 using modelⅡ. In the multitrait analyses for parameters from Logistic model, genetic and phenotypic correlations between A and k parameters were －0.43 and －0.67 using model Ⅰ and －0.50 and －0.63 using modelⅡ. Those between the A and b parameters were 0.47 and 0.22 using modelⅠ and 0.38 and 0.24 using modelⅡ. Those between the b and k parameters were －0.09 and 0.02 using model Ⅰ and －0.02 and 0.13 using model Ⅱ.

• The korean journal of orthodontics
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• v.39 no.3
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• pp.159-167
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• 2009

Objective: This study investigated the onset, peak height velocity (PHV) and end of adolescent growth spurt as well as menarcheal timing deduced from surveying accumulative height growth over many years. Methods: Ninety six students of Samgoe high school between 1st and 3rd grade that were in good health participated in the research. A survey questionnaire was distributed to examine the students' health status and menarche timing. Results: Adolescent growth spurt typically began at the age of 9.9 and reached a PHV at the age of 11.6. The growth spurt ended at the age of 14.1 on average. The average age of menarche was 12.6 years, which was about one year after the PHV of adolescent growth spurt. In most cases, menarche came after PHV. But in 24% of the students, menarche and PHV was nearly coincident or menarche preceded PHV. The growth curves were classified into four types. A typical adolescent growth spurt showed one PHV on graph that drastically drops after the PHV. However, there were cases with two PHVs. Conclusions: The results indicate that individual growth patterns show large individual differences, however the categorization into the various growth curves may aid in predicting individual growth patterns.

• The Korean Journal of Applied Statistics
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• v.12 no.2
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• pp.315-323
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• 1999

이 논문에서는 국내 우편통계의 현황에 대하여 간략히 언급하고 있으며 접수 우편물량에 대한 기술통계와 배달 우편물량에 대한 추정을 다루고 있다. 성장곡선모형을 이용하여 접수 우편물량에 대한 예측을 논의하였고 성장곡선모형 중에서 삼차곡선이 매우 잘 적합시키는 것을 확인할 수 있었다. 또한 체신청별 배달 우편물량을 체신청별 접수 우편물량과 마코프 연쇄에서 나타나는 전이행렬을 이용하여 추정하였으며 이는 표본이 비추정의 기본 개념과 일맥 상통함을 발견하였다.

• Journal of the Korean Data and Information Science Society
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• v.10 no.2
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• pp.369-385
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• 1999

For the growth curve model with arbitrary covariance structure, known as unstructured covariance matrix, the problems of detecting outliers are discussed in this paper. In order to detect outliers in the growth curve model, the likelihood ratio testing statistics in mean shift model is established and its distribution is derived. After we detected outliers in growth curve model, we test homo and/or hetero-geneous covariance matrices using PSR Quasi-Bayes Criterion. For illustration, one numerical example is discussed, which compares between before and after outlier deleting.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.887-908
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• 2022

In order to confirm the effects of economic growth and environmental improvement, this study analyzed the existence of environmental Kuznets curve (EKC) for SO₂ emission, greenhouse gas emission, and waste generation in OECD countries. As a result of panel analysis, the shape of the EKC were different depending on environmental pollutants. SO₂ generated peaks relatively early in economic growth, and the peak of greenhouse gas emissions was showed in higher income level. But both emissions showed the a complete inverted U-shaped curve decreasing after the peak. On the other hand, for waste, there was no environmental Kuznets curve that could confirm the peak. Therefore, this study confirmed that it is difficult to expect a voluntary reduction in all environmental pollutants, and additional global joint efforts are needed to pass the peak. In particular, since waste has a greater impact on population density and industrial structure than income level, additional policy efforts are needed to reduce generation and create a resource circulation system.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.503-508
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• 2004

This study was conducted to estimate the growth curve parameters of crossbreds between Korean native boars and Landrace sows and their relationships with meat qualities. The data used were weight-age data and carcass data from 131 males and 122 females raised at N.L.R.I in Korea. Growth curve parameters were estimated from nonlinear regression using Gompertz model individually. Average mature weight(A), average maturing rate(k), and average inflection point(u) showing maximum growth rate estimated were 179.54${\pm}$6.06kg, 0.3154${\pm}$0.0059, and 5.50${\pm}$0.11 months in females, and 179.84${\pm}$6.33kg, 0.3049${\pm}$0.0061, and 5.24${\pm}$0.13 months in males, respectively. For the growth curve parameters and derived statistics, the phenotypic correlations of maturing rate with gain rate at inflection, mature weight, and inflection point were - .30, - .77, and - .93 in male, and - .31, - .78 and - .94 in female, respectively. Matrure weight was positively correlated to the inflection point as + .89 in both male and female, indicating that late maturing pigs with lower k had longer maturing period with increasing gain rate and reached point of inflection later than early maturing pigs with higher k, and grew to larger mature weight. Backfat thickness and erode fat contents were correlated with mature weight positively in male and negatively in female, and correlated with gain rate at inflection point positively in both male and female, of which coefficients were as high as .42 and .50 in male, respectively.