• Journal of the Korean Data and Information Science Society
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• v.20 no.5
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• pp.787-796
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• 2009

A random coefficient model is applied when times of the repeated measurements are not fixed in experiments with respect to the subjects. The procedures of the inference of a random coefficient model are same as those of a mixed model. Diet experimental data was used for applying the random coefficient model. Various random coefficient models are investigated for the experimental data, and are compared each other. Finally, optimal random coefficient model would be selected. It resulted from the analysis that for the fixed effect factor, the baseline, treatment, height, and time effect were very significant. The treatment effect of the diet foods and exercises were more effective in losing weight than the effect of the diet foods only. The fixed cubic time effect was very significant. The variance components corresponding to the subject effect, linear time effect, quadratic time effect, and cubic time effect of the random coefficients are all positive. When quartic time effect was added as random coefficients the model did not converge. Thus random coefficients up to the cubic terms was considered as the optimal model.

• Journal of Animal Science and Technology
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• v.54 no.2
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• pp.71-75
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• 2012

The present study data were obtained from 36,894 cows in Korea Animal Improvement Association from 2001 to 2009 which was subjected for ultrasound measurements (eye muscle area, back-fat thickness, marbling score) and descent. Repeated record models were carried out using 7,913 of 36,894 of total animal traits. The ultrasound measured traits and performance test data were used to study the chest girth, body condition score, eye muscle area, back-fat thickness and marbling score with genetic correlation and parameters for the ultrasound measured traits using REMLF90 program. Genetic correlation of eye muscle area with back-fat thickness, marbling score and back-fat thickness with marbling score were noticed in repeated records animal model as 0.69, 0.54, and 0.59, whereas in multiple trait animal model method were 0.07, 0.66, and 0.39, respectively. Repeated records of animal models were used as positive correlation of traits. Multiple trait animal models were used as negative correlation of eye muscle area with marbling score. The analysis on repeat records of animal models using ultrasound measurements about Korean cattle showed positive effects for each traits. In comparison differences between the repeat records of animal models and multiple trait animal models was found with higher traits of her, the heritability and repeatability was found higher in repeat records animal models. In light of these assessments, carcass traits by ultrasound measurements are expected to help and improve an accurate analysis of each trait and if the research analysis using repeat records of animal models continue when we estimate genetic ability of these traits.

• The Korean Journal of Applied Statistics
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• v.10 no.2
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• pp.325-338
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• 1997

This paper suggests a sequence of dependence models as a statistical analysis model for vaccination data on chickenpox and discusses a method for evaluating maximum likelihood estimates of unknown parameters in the suggested model.

• The Korean Journal of Applied Statistics
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• v.9 no.1
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• pp.1-15
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• 1996

This paper discusses the effectiveness of an infection rate under a certain disease on an immunity rate by a protective inoculation. A sequence of dependense models concerning the infection rate is derived by defining conditionally nested binary random variables for the analysis of polytomous data with hierarchical response scale. Maximum likelihood estimates based on the marginal log-likelihood functin are obtained numerically in the Nelder and Mead's(1965) simplex method.

• Journal of Information Management
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• v.42 no.1
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• pp.113-135
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• 2011

The final report of the Functional Requirement of Subject Authority Data(FRSAD), the 3rd report of the FRBR family model, is announced by IFLA in June, 2010. This model represents the international trends of subject authority control and suggests a direction to the future subject authority record suitable for the FRBR system. Therefore aims of this study are to analysis the FRSAD model in context of the FRBR family and apply the model to the subject headings and bibliographic records of Korean National Library. For these aims, we analyse the model focused on the entities, attributes, and relationships between entities. From this analysis, we have found the openness of the FRSAD, which does not force a certain entity types and has focus on the conceptual aspects of the entity not only the form of the headings. Moreover, we suggest examples by applying the FRSAD frame and facets of the FAST to the Headings of the NLSH and related KORMARC fields. The scope of this study is the additional entities of the FRBR groups, so personal names, corporate names, family names and titles are not included. As a result, it is necessary to determine the criteria for the types of thema and to apply the types consistently in bibliographic records. A follow up research will be needed to suggest more detailed examples.

• Journal of the Korea Society for Simulation
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• v.2 no.1
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• pp.67-77
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• 1993

• The Korean Journal of Applied Statistics
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• v.21 no.2
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• pp.291-299
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• 2008

This paper discusses model building for repeated binary response data with different time-dependent covariates each occasion. Since repeated measurements data are having correlated structure, weighed least squares(WLS) methodology is applied. Repeated measures designs are usually having different sizes of experimental units like split-plot designs. However repeated measures designs differ from split-plot designs in that the levels of one or more factors cannot be randomly assigned to one or more of the sizes of experimental units in the experiment. In this case, the levels of time cannot be assigned at random to the time intervals. Because of this nonrandom assignment, the errors corresponding to the respective experimental units may have a covariance matrix. So, the estimates of effects included in a suggested logit model are obtained by using covariance structures.

• Journal of the Korean Data and Information Science Society
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• v.22 no.2
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• pp.287-296
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• 2011

Thirty six female students participated in the experiment of the fat mass weight loss. they kept diary for foods they ate every day, took a picture of the foods, transmitted the picture to the experimenter by the camera phone, and consulted him about fat mass loss once a week for 8 weeks period. Fat mass weight and its related factors of the students had been measured repeatedly every week during 8 weeks, The repeated measurement data were used for applying various random coefficient models. And hence optimal random coefficient model was selected. From the optimal model, the baseline, body mass index, diastolic blood pressure, total cholesterol and time of the fixed factors were very significant. The fixed quadratic time effect existed. The variance components corresponding to the subject effect, linear time effect of the random coefficients were all positive. Thus random coefficients up to the linear terms were considered as the optimal model. The treatment effect reduced the weight loss to an average of 2.1kg at the end of the period.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.512-512
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• 2023

내성천은 대한민국의 대표적인 모래하천으로서 흰수마자(Gobiobotia naktongensis)의 최적 서식처로 알려져 있다. 흰수마자는 낙동강에서 채집되어 새로운 종으로 보고된 한국 고유종이지만 최근 멸종위기야생생물 I급 담수어류로 지정되었다. 흰수마자는 입자가 1 mm 이하의 가는 모래로 90% 이상 구성된 모래하상과 수질이 양호한 곳에서 서식하는 것으로 알려져 있다(Kim et al, 2014). 특히 낙동강 중류의 감천과 상류의 내성천 수계에서 비교적 많은 개체수가 출현하고 있는 것으로 보고되었다(Na et al., 2015). 그러나 영주댐 건설 이후, 댐 하류 내성천에서 흰수마자의 개체수가 급격히 줄어들었다. 2021년 내성천 유역 자연성생태계모니터링 보고서(환경부, 2022)에 따르면 내성천에서 흰수마자가 2016년에 492개체가 채집된 이후 2019년 7월엔 1개체만이 채집되었으며 이후 2022년 8월까지 채집되지 않았다. 반면 망둥어과 어류 중 입자가 굵은 하상환경에서 주로 서식하는 밀어의 개체수는 증가하는 경향을 보였다. 이는 내성천 유역의 하상환경변화가 어류서식에 직간접적으로 영향을 미친것으로 해석할 수 있다. 본 연구는 물리서식처 모형인 River2D를 활용하여 내성천 석탑교(No. 46) 에서 회룡교(No. 4)까지 약 40 km 구간을 대상으로 2010년 하상 입자와 2020년 하상 입자 크기에 따른 흰수마자의 서식처 적합도 변동양상을 분석하였다. River2D 모형을 통해 계산되는 어류 서식처 적합도는 물리서식처 모의시스템에서 사용되는 가중가용면적(WUA: Weighted Usable Area)에 근거하여 산출된다. WUA는 대성어종의 특정 성장단계별, 서식처 특성별로 주어진 구간을 이용할 수 있는 순수적합도(net suitability)에 대한 하나의 지표이다. WUA가 크다는 것은 그만큼 대상어종의 서식처 및 활동 영역이 크다는 것을 의미한다. WUA는 각 절점에서 평가되어지는 복합서식처 적합도 지수에 의해 계산된다. 본 연구에서는 곱셈방법을 적용한 복합 서식처 적합도 지수를 산정하여 하상입자에 따른 흰수마자의 서식처 적합도 변동양상을 분석하였다.

• Journal of Wetlands Research
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• v.23 no.2
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• pp.122-132
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• 2021

We reviewed the methods employed in Korean tidal flat surveys to measure the local abundance of the endangered wildlife and marine protected species, the fiddler crab, Austruca lactea. A complete census for infinite population is impossible even in a limited habitat within a tidal flat, and density estimates from samples strongly vary due to diverse biological and ecological factors. The habitat boundaries and areas shift with periodicities or rhythmic activities of organisms as well as measurement errors. Hence the local abundance calculated from density and habitat areas should be regarded as transient. This conjecture was valid based on the spatio-temporal variations of the density averages, standard error ranges, and spatial distribution of the crab, A. lactea observed for 3 years (2015-2017) in Songdo tidal flat in Incheon. We proposed the potential habitat areas using the occurrence probability of 50% from logistic regression model, reflecting the importance of habitat conservation value as an alternative to local abundance. The spatial shape of potential habitat predicted from a generalized model would remain constant over time unless the species' critical environmental conditions change rapidly. The species-specific model is expected to be used for the introduction of desired species in future habitat restoration/creation projects.