• Korean Journal of Construction Engineering and Management
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• v.22 no.5
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• pp.86-98
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• 2021

In this study, we developed a simulation model for supply chain management of Precast Concrete (PC) based construction. To this end, information on the Factory Production/Site Construction system was collected through literature review and field research, and based on this information, a simulation model was defined by describing the supply chain, entities, resources, and processes. Next, using the Arena simulation software, a simulation model for the PC supply chain was developed by setting model frameworks, data modules, flowchart modules, and animation modules. Finally, verification and validation were performed using five review methodologies such as model check, animation check, extreme value test, average value test, and actual case test to the developed model. As a result, it was found that the model adequately represented the flows and characteristics of the PC supply chain without any logical errors and provided accurate performance evaluation values for the target supply chains. It is expected that the proposed simulation model will faithfully play a role as a performance evaluation platform in the future for developing management techniques in order to optimally operate the PC supply chain.

• The Korean Journal of Applied Statistics
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• v.33 no.4
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• pp.379-393
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• 2020

A terminal event such as death may censor an intermediate event such as relapse, but not vice versa in semi-competing risks data, which is often seen in medicine, public health, and epidemiology. We propose a Weibull regression model with a normal frailty to analyze semi-competing risks data when all three transition times of the illness-death model are possibly interval-censored. We construct the conditional likelihood separately depending on the types of subjects: still alive with or without the intermediate event, dead with or without the intermediate event, and dead with the intermediate event missing. Optimal parameter estimates are obtained from the iterative quasi-Newton algorithm after the marginalization of the full likelihood using the adaptive importance sampling. We illustrate the proposed method with extensive simulation studies and PAQUID (Personnes Agées Quid) data.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.640-644
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• 2010

하천, 호소 등에서 공사 시 준설작업으로 인해 고탁수가 발생되며 이러한 탁수의 이송 확산은 수환경에 변화를 초래한다. 탁수는 준설작업 시 커터헤드(cutter head)가 해저면에 닿는 순간부터 작동을 멈출 때까지 계속하여 발생하며, 이러한 과정들이 반복되면서 많은 양의 부유토사가 발생하게 되고 고탁수현상이 일어난다. 이렇게 발생한 탁수는 수체흐름에 따라 이송 및 확산된다. 탁수발생은 수중의 빛 투과를 감소시켜 일차 생산자인 부유성 및 부착조류의 생육을 저해하고, 이들의 생산성 감소와 군집구성의 변화는 수서생태계의 먹이사슬을 통해 이들을 먹이로 하는 저서무척추동물과 어류의 현존량 감소와 종 구성에 영향을 미치고, 고농도의 현탁 입자는 어류 아가미에 염증을 유발하거나 점막의 파괴와 감염을 유발하여 치사시킬 수도 있다. 또한 과도한 부유 입자는 하류로 침강되어 하천 바닥에 서식하는 부착조류, 무척추 동물 및 곤충의 생육에 피해를 주고, 이것은 어류의 먹이에 영향을 미쳐 어류 개체수를 감소시키거나 산란된 물고기 알을 매몰시키거나 질식시키는 등 여러 가지 방법으로 수서생물상에 영향을 미치게 된다.(낙동강수계관리위원회, 2005) 따라서 준설작업에 있어 탁수의 이송 확산범위를 사전에 예측하고 국내 실정과 환경여건에 알맞게 적용되고, 실용화될 수 있는 수치모델링에 대한 기반핵심 기술개발이 필요하다. 현재 낙동강에서 진행되고 있는 준설현장에서 발생하는 부유탁수의 이송 확산과정을 이차원 흐름해석모형인 RAM2 모형과 오염물 이송 확산해석모형인 RAM4 모형을 이용하여 수치해석을 하고 분석함으로써 수치해석에 의한 부유탁수의 이송 확산모의 결과가 환경영향 범위를 예측하는 데에 적용될 수 있는지를 알아보고자 한다.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.169-178
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• 2010

Agent based simulation is an approach for the analysis of a system's long term behavior where the entities in the system behave independently by their own judgement and memory, but influence each other to cope with given environment. In this paper we developed an agent based simulation model for the analysis of behavioral mechanism of team formation. In the process of team formation members' mutual preference is an important factor although each member can join up with one's own will. Also a team performance can vary by the member's own experience. We implemented the developed model using Netlogo 4.1, and verified the model by simulation. From the simulation results we found that the model successfully performed necessary functions using behavioral rules, judgments, and evolutionary processes by memory. As a further study we will be able to apply the model for analyzing various ecological behavior of team formation.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.2
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• pp.94-106
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• 2018

The epidemiological model is useful for creating simulation and associated preventive measures for disease spread, and provides a detailed understanding of the spread of disease space through contact with individuals. In this study, propose an agent-based spatial model(ABM) integrated with spatial big data to simulate the spread of MERS-CoV infections in real time as a result of the interaction between individuals in space. The model described direct contact between individuals and hospitals, taking into account three factors : population, time, and space. The dynamic relationship of the population was based on the MERS-CoV case in Seoul Metropolitan Government in 2015. The model was used to predict the occurrence of MERS, compare the actual spread of MERS with the results of this model by time series, and verify the validity of the model by applying various scenarios. Testing various preventive measures using the measures proposed to select a quarantine strategy in the event of MERS-CoV outbreaks is expected to play an important role in controlling the spread of MERS-CoV.

• Journal of The Korean Association For Science Education
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• v.35 no.4
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• pp.691-707
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• 2015

This study aims to develop biology teachers' education program based on argumentation activity about core concepts of evolution and to analyze the characteristics of core concepts of evolution learned during the program. The eight core concepts of evolution in this study were variation, heritability of variation, competition, natural selection, adaptation, differential reproductive rate of individuals, changes in genetic pool within a population, and macroevolution. The performances of teachers participating in the program were compared before and after argumentation activities; consisting of seven sessions on the eight core concepts of evolution. The process of the program was specially designed by learning cycle model for teacher education, consisting of seven phases: identification of the task, production of a tentative argument, small group's written argument, share arguments with the other groups, reflective discussion, final written argument, and organization by an instructor. Participants in the study were two pre-service biology teachers and four in-service biology teachers. The results suggest that biology teachers reduced the teleological explanation for biological evolution and improve its adequacy after the intervention. Teachers lacked the opportunity to discuss variation, heritability of variation, competition, and macroevolution because science textbooks lack information on the concepts of biological evolution. The results of this study suggest that because the argumentation program developed for teachers helps to improve understanding the concepts of evolution and to reduce inadequate conceptions in biology, teacher education programs using argumentation activity and eight core concepts of evolution will play a role for efficient evolution education for biology teachers.

• Korean Journal of Environmental Biology
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• v.34 no.1
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• pp.56-62
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• 2016

Pest population density models are very important to monitor the initial occurrence and to understand the continuous fluctuation pattern of pest in pest management. This is one of the major issues in agriculture because these predictions make pesticides more effective and environmental impact of pesticides less. In this study, we combined and predicted the mortality change of pest caused by pesticides with temperature change and population dynamic model. Sensitive strain of two-spotted spider mite (Tetranychus urticae Koch) with kidney bean leaf as host was exposed to mixed acaricide, Acrinathrin-Spiromesifen and organotin acaricide, Azocyclotin, at 20, 25, 30, and $35^{\circ}C$, respectively. There was significant difference in mortality of T. urticae among pesticides and temperatures. We used DYMEX to simulate population density of T. urticae and predicted that the initial management time and number of chemical control would be changed in the future with climate change. There would be implications for strategies for pest management and selection process of pesticide in the future corresponding climate change.

• Korean Journal of Clinical Pharmacy
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• v.20 no.1
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• pp.9-16
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• 2010

Purpose: 본 연구는 한국인 성인 조혈모세포이식환자를 대상으로 경구용 사이클로스포린의 집단약동학 분석을 통하여 사이클로스포린의 약동학적 파라미터에 영향을 미치는 요인 분석을 실시하고자 하였다. Methods: 2000년 12월부터 2006년 8월까지 서울대학교병원에서 동종조혈모세포이식을 받고 면역억제제로 사이클로스포린을 복용한 성인 백혈병환자를 대상으로 후향적으로 자료를 수집하였다. 사이클로스포린의 약동학에 영향을 미치는 인자로는 연령, 성별, 이식 후 날짜, 신기능, 공여자와의 관계, 질병의 종류, 혈중 빌리루빈 농도, 사이클로스포린의 대사를 유도하는 프레드니솔론의 투여량, 헤마토크리트, 사이클로스포린의 대사를 저해하는 약물의 병용여부 등을 검토하였다. 분석은 NONMEM$^{(R)}$ VI 프로그램을 이용하였으며, 변수를 추가하지 않은 기본 모형을 만든 후에 단계적인 요인의 추가와 제거를 통해 최종모형을 제작하였다. Results: 최종 상관 모형은 다음과 같다; CL/F (L/h) = $85.6{\times}e^{(0.646\;{\times}\;HCT/28.9\;+\;0.0464\;{\times}\;Gender)}$. 사이클로스포린의 겉보기 클리어런스는 환자의 성별이 남자일 때 또는 헤마토크릿이 감소할수록 증가하였다. 그 외 파라미터는 다음과 같이 계산되었다; $K_{\alpha}=0.0787\;(h^{-1})$; Q=57.1(L/kg/h); $V_{d-central\;compartment}$=1,100 (L); $V_{d-peripheral\;compartment}$ = 213,000(L). 개체간 편차는 40% 미만이었으며, 개체내 편차를 포함하는 잔차는 24.02%였다. Conclusions: 사이클로스포린의 약동학적 특징과 그 클리어런스에 영향을 끼칠 수 있는 임상적 요인을 이해하는 것은 환자 개개인의 용량과 용법의 결정 및 이상반응 발생의 예방에 유용할 수 있다. 한국인 조혈모세포이식환자에서 사이클로스포린의 약동학에 영향을 미치는 최종 파라미터를 구한 본 연구의 결과는 조혈모세포이식을 받은 한국인 성인환자에서 사이클로스포린의 모니터링 및 용량조절에 유용할 것으로 전망된다.

• Journal of The Korean Association For Science Education
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• v.29 no.8
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• pp.990-1010
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• 2009

To derive brain-based evolutionary educational principles, this study examined the studies on the structural and functional characteristics of human brain, the biological evolution occurring between- and within-organism, and the evolutionary attributes embedded in science itself and individual scientist's scientific activities. On the basis of the core characteristics of human brain and the framework of universal Darwinism or universal selectionism consisted of generation-test-retention (g-t-r) processes, a Model of Brain-based Evolutionary Scientific Teaching for Learning (BEST-L) was developed. The model consists of three components, three steps, and assessment part. The three components are the affective (A), behavioral (B), and cognitive (C) components. Each component consists of three steps of Diversifying $\rightarrow$ Emulating (Executing, Estimating, Evaluating) $\rightarrow$ Furthering (ABC-DEF). The model is 'brain-based' in the aspect of consecutive incorporation of the affective component which is based on limbic system of human brain associated with emotions, the behavioral component which is associated with the occipital lobes performing visual processing, temporal lobes performing functions of language generation and understanding, and parietal lobes, which receive and process sensory information and execute motor activities of the body, and the cognitive component which is based on the prefrontal lobes involved in thinking, planning, judging, and problem solving. On the other hand, the model is 'evolutionary' in the aspect of proceeding according to the processes of the diversifying step to generate variants in each component, the emulating step to test and select useful or valuable things among the variants, and the furthering step to extend or apply the selected things. For three components of ABC, to reflect the importance of emotional factors as a starting point in scientific activity as well as the dominant role of limbic system relative to cortex of brain, the model emphasizes the DARWIN (Driving Affective Realm for Whole Intellectual Network) approach.

• Korean Journal of Environment and Ecology
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• v.11 no.3
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• pp.352-365
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• 1997

As a serials of researches for the restoration model of evergreen broad-leaved forests, the restoration strategies of the case study areas were proposed. Restoration type of vegetation were classified into an improvement type and a reconstruction type and a reconstruction type for Wando(Island). Improvement type of restoration was suggested for Mokdo(Island). Quercus acuta community, Q. salicina community, Neolitsea sericea community, Castanopsis cuspidata var. sieboldii community, Machilus thunbergii community, Cinnamomum japonicum community, etc. were suggested as a restoration goal of vegetation for Sando(Island). Machlus thunvergii community was suggested as a restoration goal of vegetation for Mokdo(Island). Also the species restoration olan of the Wando(Island) was prepared for Quercus salicina of Fagaceae and Ostrya japonica of Betulaceae those which the natural distribution and population size were very limited. There was no species which needed for species restoration urgently at Mokdo(Island).