• Title/Summary/Keyword: Latent Difference Score Model

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Examining the Association of Poverty Status Transition with the Causal Relationship between Drinking Problem and Depression (음주문제와 우울 간의 인과관계와 빈곤상태 변화의 연관성 분석)

  • Hoe, Maanse
    • Korean Journal of Social Welfare
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    • v.65 no.2
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    • pp.203-230
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    • 2013
  • The present study aimed to analyze possible causal relationship between drinking problem and depression. In addition, The study examined if poverty status transition is associated with the causal relationship between drinking problem and depression. The study sample consisted of 3,976 adults who have participated in both the first and the second wave survey of the Korea Welfare Panel Study. The causality between drinking problem and depression was analyzed using Latent Difference Scores (LDS) model, which was established in McArdle & Hanagami (2001). Furthermore, it was examined if poverty status transition (represented by four subgroups: poverty-sustained group, poverty-escaping group, non-poverty-sustained group, poverty beginning group) would influence the causal relationship between drinking problem and depression. The major findings are as follows. The result of a LDS model analysis using the entire sample shows that depression at the first wave predicts significantly the change of drinking problem between the first wave and the second wave and also drinking problem at the first wave predicts significantly the change of depression between the first wave and the second wave, which can be interpreted as there is reciprocal causal relationship between depression and drinking problem. In poverty status transition subgroup analyses, the reciprocal causal relationship between depression and drinking problem is held in the poverty-sustained group while depression is a cause of drinking problem both in the poverty beginning group and in the non-poverty-sustained group. However, there is no significant causal relationship between depression and drinking problem in the poverty-escaping group. All these findings indicate that the direction of causality between depression and drinking problem can be varied according the poverty status change, which provides a comprehensive explanation to inconsistent research findings from previous cross-section studies of the relationship between depression and drinking problem.

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Study on the Academic Competency Assessment of Herbology Test using Rasch Model (라쉬 모델을 사용한 본초학 시험의 학업역량 분석 연구)

  • Chae, Han;Lee, Soo Jin;Han, Chang-ho;Cho, Young Il;Kim, Hyungwoo
    • The Journal of Korean Medicine
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    • v.43 no.2
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    • pp.27-41
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    • 2022
  • Objectives: There should be an objective analysis on the academic competency for incorporating Computer-based Test (CBT) in the education of traditional Korean medicine (TKM). However, the Item Response Theory (IRT) for analyzing latent competency has not been introduced for its difficulty in calculation, interpretation and utilization. Methods: The current study analyzed responses of 390 students of 8 years to the herbology test with 14 items by utilizing Rasch model, and the characteristics of test and items were evaluated by using characteristic curve, information curve, difficulty, academic competency, and test score. The academic competency of the students across gender and years were presented with scale characteristic curve, Kernel density map, and Wright map, and examined based on T-test and ANOVA. Results: The estimated item, test, and ability parameters based on Rasch model provided reliable information on academic competency, and organized insights on students, test and items not available with test score calculated by the summation of item scores. The test showed acceptable validity for analyzing academic competency, but some of items revealed difficulty parameters to be modified with Wright map. The gender difference was not distinctive, however the differences between test years were obvious with Kernel density map. Conclusion: The current study analyzed the responses in the herbology test for measuring academic competency in the education of TKM using Rasch model, and structured analysis for competency-based Teaching in the e-learning era was suggested. It would provide the foundation for the learning analytics essential for self-directed learning and competency adaptive learning in TKM.

An Analysis of Heating and Cooling Loads by Insulated Shades and Control Method in an Energy Saving Apartment (에너지절약형 주택에서의 단열차양 적용과 제어방법에 따른 냉난방부하 분석)

  • Kwon, Kyung-Woo;Won, Jong-Seo
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.33-38
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    • 2009
  • Energy loss from windows accounts for large scores of heating and cooling loads also in energy saving apartments that is reduced over 30% of total energy consumption. Movable reflective insulations, insulation shutters, blinds, insulated shades are used to reduce energy loads from windows. In this study, energy saving performance of insulated shades was simulated by control methods. According to installation of insulated shades, heating loads were decreased about $10.5{\sim}11.3%$, and cooling loads are decreased about $11.0{\sim}15.5%$ on an energy saving apartment. The heating peak load was reduced about 9.5% by insulated shades, but the cooling peak load is hardly ever decreased. Because in the condition of cooling peak load, latent cooling loads accounts for large score of cooling loads. Difference of the energy loads by a schedule control method and an outdoor detection control was no more than 5% for a base model. In the case of insulated shades with automatic control system, simple time schedule control system would be more efficient than outdoor detection control system that should use several sensors.

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The NCAM Land-Atmosphere Modeling Package (LAMP) Version 1: Implementation and Evaluation (국가농림기상센터 지면대기모델링패키지(NCAM-LAMP) 버전 1: 구축 및 평가)

  • Lee, Seung-Jae;Song, Jiae;Kim, Yu-Jung
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.18 no.4
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    • pp.307-319
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    • 2016
  • A Land-Atmosphere Modeling Package (LAMP) for supporting agricultural and forest management was developed at the National Center for AgroMeteorology (NCAM). The package is comprised of two components; one is the Weather Research and Forecasting modeling system (WRF) coupled with Noah-Multiparameterization options (Noah-MP) Land Surface Model (LSM) and the other is an offline one-dimensional LSM. The objective of this paper is to briefly describe the two components of the NCAM-LAMP and to evaluate their initial performance. The coupled WRF/Noah-MP system is configured with a parent domain over East Asia and three nested domains with a finest horizontal grid size of 810 m. The innermost domain covers two Gwangneung deciduous and coniferous KoFlux sites (GDK and GCK). The model is integrated for about 8 days with the initial and boundary conditions taken from the National Centers for Environmental Prediction (NCEP) Final Analysis (FNL) data. The verification variables are 2-m air temperature, 10-m wind, 2-m humidity, and surface precipitation for the WRF/Noah-MP coupled system. Skill scores are calculated for each domain and two dynamic vegetation options using the difference between the observed data from the Korea Meteorological Administration (KMA) and the simulated data from the WRF/Noah-MP coupled system. The accuracy of precipitation simulation is examined using a contingency table that is made up of the Probability of Detection (POD) and the Equitable Threat Score (ETS). The standalone LSM simulation is conducted for one year with the original settings and is compared with the KoFlux site observation for net radiation, sensible heat flux, latent heat flux, and soil moisture variables. According to results, the innermost domain (810 m resolution) among all domains showed the minimum root mean square error for 2-m air temperature, 10-m wind, and 2-m humidity. Turning on the dynamic vegetation had a tendency of reducing 10-m wind simulation errors in all domains. The first nested domain (7,290 m resolution) showed the highest precipitation score, but showed little advantage compared with using the dynamic vegetation. On the other hand, the offline one-dimensional Noah-MP LSM simulation captured the site observed pattern and magnitude of radiative fluxes and soil moisture, and it left room for further improvement through supplementing the model input of leaf area index and finding a proper combination of model physics.