• 한국임상약학회지
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• 제31권2호
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• pp.125-135
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• 2021

Background: Generally, pharmacokinetics (PK) models could be stratified into two models. The compartment PK model uses the concept of simple compartmentalization to describe complex bodies, and the physiologically based pharmacokinetic (PBPK) model describes the body using multi-compartment networking. Notwithstanding sharing a theoretical background in both models, there was still a lack of knowledge to enhance compatibility in both models. Objective: This study aimed to evaluate the compatibility among PBPK, lumping model and compartment PK model with voriconazole PK case study. Methods: The number of compartments and blood flow on each tissue in the PBPK model were modified using the lumping method, considering physiological similarities. The concentration-time profiles and area under the concentration-time curve (AUC) parameters were simulated at each model, assuming taken voriconazole oral 400 mg single dose. After that, those mentioned PK parameters were compared. Results: The PK profiles and parameters of voriconazole in the three models were similar that proves their compatibility. The AUC of central compartment in the PBPK and lumping model was within a 2-fold range compared to those in the 2- compartment model. The AUC of non-eliminating tissues compartment in the PBPK model was similar to those in the lumping model. Conclusion: Regarding the compatibility of the three PK models, the utilization of the lumping method was confirmed by suggesting its reliable PK parameters with PBPK and compartment PK models. Further case studies are recommended to confirm our findings.

• 방사성폐기물학회지
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• 제5권1호
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• pp.29-37
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• 2007

특정 구획으로 유입된 오염물질이 해당 구획 내부에 순간적으로 균일하게 분포한다는 구획모델에 대한 기본가정의 한계로 인해, 전통적인 단일구획모델로는 불포화대에서 오염물질의 이동현상을 적절하게 예측할 수 없다. 한편 물리적으로 동일한 불포화대를 여러 개의 구획으로 구분한 다중구획모델링 기법은 실제 불포화대에서의 오염물질 이동 지연효과를 적절하게 설명할 수 있으나, 지금까지 일반적인 해석해가 보고된 바 없으며 고려하는 구획의 개수가 증가할수록 모델링에 많은 시간이 소요되는 등의 한계가 있다. 이러한 문제점을 해결하기 위하여, 이류가 지배적인 조건 하에서 불포화대의 오염물질 이동현상에 대한 다중구획모델을 수립하고 이를 해석적인 방법으로 계산할 수 있는 일반해를 유도한 후, 다중구획모델을 단일구획모델로 근사할 수 있는 수학적 제약조건을 도출하였다. 단순화된 근사방법론의 유효성은 가상적인 조건 하에서 간단한 수치해석적 방법을 통해 검증하였다. 물리적으로 동일한 특성을 갖는 불포화대를 단일 구획으로 가정할 경우, 불포화대로부터 포화대로 유입되는 오염물질의 전이율은 상수가 아닌 시간 종속적인 명목전이율로 표현할 수 있음을 증명하였다. 또한 명목전이율은 불포화대 구획간 전이율에 민감하며 오염층으로부터의 전이율에 대한 민감도는 미미한 것으로 나타났다. 이 연구에서 개발된 단순화된 근사방법론은 많은 시간이 요구되는 다중구획 모델링을 통하지 않고 불포화대 오염물질 이동현상을 신속하고 합리적으로 예측하기 위한 목적으로 활용될 수 있을 것으로 기대된다.

• 한국어병학회지
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• 제21권2호
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• pp.119-127
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• 2008

Oxytetracycline (OTC) has been widely used in eel culture as a therapeutic and prophylactic agent because of its broad-spectrum activity against gram-positive and -negative bacteria. The oral treatment dosage of OTC approved for the treatment of edwardsiellosis, furunculosis and vibriosis in eel is 50 mg/kg/day for 3-7 days in Korea. To determine new optimum dose of OTC in eel, the pharmacokinetics of OTC after single oral administration (100 mg/kg B.W., 200 mg/kg B.W.) in cultured eel, Anguilla japonica was examined. In oral dosage of 100 and 200 mg/kg body weight, the highest plasma concentrations of OTC were 1.19±0.42 ㎍/㎖ and 2.69±0.57 ㎍/㎖, respectively. Plasma concentrations of OTC were not detected after 720 h post-dose in all experiments. The kinetic profile of absorption, distribution and elimination of OTC in plasma wwas calculated fitting to a 1- and 2-compartment model by WinNonlin program. The following parameters were obtained for a single dosage of 100 and 200 mg/kg respectively: 1-compartment model, AUC= 82.48 and 432.68 ㎍*h/㎖, Tmax= 3.93 and 14.24 hr, Cmax= 0.94 and 2.34 ㎕/㎖; 2-compartment model, AUC= 448.73 and 530.65 ㎍*h/㎖, Tmax= 6.37 and 8.96 hr, Cmax= 0.90 and 3.21 ㎕/㎖.

• 대한핵의학회지
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• 제29권1호
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• pp.48-53
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• 1995

Rb-82 dynamic PET과 이중적분법에 의한 국소 심근 혈류측정 연구를 시행하고자 실험 개를 이용한 심근 혈전증 모델에서 좌심실 입력함수에 의한 정상 및 관류결손 심근에서의 혈류를 측정하였다. 이중적분법이 선형회귀모델에 의한 혈류측정방법에 비하여 실현이 간단하고 심근내 혈류가 선형적인 가정을 배제할 수 있어 더욱 정확한 방법이 될 수 있음을 확인하였다.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 춘계학술논문발표회 논문집
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• pp.290-293
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• 2008

In this study, the Computational Fluid Dynamics (CFD) has been used to analyze the smoke movement and the carbon monoxide concentration distribution, both vertically and longitudinally, in a compartment, based on conservation laws. The Fire Dynamics Simulator (FDS) developed by National Institute of Standards and Technology (NIST) was used for numerical simulations using Reynolds averaged Navier-Stokes equations (RANS) model to solve for time-averaged properties. Results show, as a function of time, a detailed distribution of temperature and carbon monoxide concentration changing against the height above the floor and those changes alongside the distance away from the fire source. Fire-induced smoke and toxic gases like CO are more dangerous in a confined space. The result of study may contribute in designing the smoke evacuation system based on the precise tenable condition.

• Nuclear Engineering and Technology
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• 제43권3호
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• pp.271-278
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• 2011

When performing fire PSA in a nuclear power plant, an event mapping method, using an internal event PSA model, is widely used to reduce the resources used by fire PSA model development. Feasible initiating events and component failure events due to fire are identified to transform the fault tree (FT) for an internal event PSA into one for a fire PSA using the event mapping method. A surrogate event or damage term method is used to condition the FT of the internal PSA. The surrogate event or the damage term plays the role of flagging whether the system/component in a fire compartment is damaged or not, depending on the fire being initiated from a specified compartment. These methods usually require explicit states of all compartments to be modeled in a fire area. Fire event scenarios, when using explicit identification, such as surrogate or damage terms, have two problems: (1) there is no consideration of multiple fire propagation beyond a single propagation to an adjacent compartment, and (2) there is no consideration of simultaneous fire propagations in which an initiating fire event is propagated to multiple paths simultaneously. The present paper suggests a fire propagation equation to identify all possible fire event scenarios for an explicitly treated fire event scenario in the fire PSA. Also, a method for separating fire events was developed to make all fire events a set of mutually exclusive events, which can facilitate arithmetic summation in fire risk quantification. A simple example is given to confirm the applicability of the present method for a $2{\times}3$ rectangular fire area. Also, a feasible asymptotic approach is discussed to reduce the computational burden for fire risk quantification.

• 한국시뮬레이션학회논문지
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• 제26권3호
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• pp.1-11
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• 2017

격실 내부에서의 폭발로 인한 인원의 피해를 분석하였다. 특히 격실 내에서 폭압 전파에 영향을 미치는 돌출된 장애물의 유무에 따른 인원 피해를 비교하였다. 격실 내에 장애물이 없는 경우에 경험적 고속처리모델을 이용하여 폭압을 예측할 수 있다. 하지만 격실 내부에서는 폭압 프로파일이 개활지에서와 달리 복잡하며 의자와 같은 구조물이 존재하는 경우에는 경험적 고속처리모델 적용이 불가하다. 따라서 장애물이 있는 격실 내부 폭압은 유한요소해석을 이용해 획득하였다. 또한 개활지의 폭압 프로파일을 기준으로 개발된 Friedlander 압력-충격량 곡선을 격실 내부에서의 복잡한 폭압 전파로 인해 피해평가에 적용할 수 없어, Axelsson 단자유도 모델을 적용하여 인원 피해를 분석하였다. 장애물이 있는 경우 인원의 흉벽 속도는 26에서 76 퍼센트(%) 만큼 감소되었으며 격실내 인원피해 또한 감소되었다.

• Journal of Radiation Protection and Research
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• 제8권2호
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• pp.8-14
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• 1983

삼중수소의 단일 피폭과 만성피폭에 의한 한국인의 내부피복 선량을 삼단계형모델을 이용하여 계산하였다. 이 모델은 체내수분과 조직체 사이의 삼중 수소의 축적량을 잘 나타내 주는 것이다. 그 결과 삼단계형의 축적 반감기 9, 30과 450일을 사용한 단일 피폭의 총 선량은 1mCi/kg 섭취당 17.64mrad였고 이것의 97%는 체내수분에 있는 삼중수소에 의한 선량이고 나머지 3%는 조직내 삼중수소에 의한 것이다. 그리고 1 mCi/day의 삼중 수소를 섭취하는 만성 피폭의 경우, 총 선량은 85.5mrad/day이었다. 또한 본 연구에서는 한국인에 대한 최대허용 농도값을 선질계수 1을 사용하여 계산하였다. 그 결과, ICRP의 최대허용 농도값은 약 50%가량 낮게 평가되었으므로 한국인의 최대허용 농도값은 ICRP의 결과보다 약 50%높게 책정되어야만 한다.

• 소음진동
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• 제8권2호
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• pp.239-250
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• 1998

Traditionally, intake noise from internal combustion engine has not recevied much attention compared to exhaust noise. But nowadays, intake noise is a major contributing factor to automotive passenger compartment noise levels. The main objective of this paper is to identify the mechanism of generation, propagation and radiation of the intake noise. With a simplest geometric model, one of the main noise sources for the intake stroke is found to be the pressure surge, which is generated after intake valve closing. The pressure surge, which has the nonlinear acoustic behavior, propagates and radiates with relatively large amplitude. In this paper, unsteady compressible Navier-Stokes equations are employed for the intake stroke of axisymmetric model having a single moving cylinder and a single moving intake valve. To simulate the periodic motion of the piston and the valve, unsteady deforming mesh algorithm is employed and Thompson's non-reflecting boundary condition is applied to the radiation field. In order to resolve the small amplitude waves at the radiation field, essentially non-oscillatory(ENO) schemes with an artificial compression method (ACM) are used.

• 수산해양기술연구
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• 제52권2호
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• pp.88-95
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• 2016

Most grid sorting has been used to sort out flatfish in shrimp fisheries, while double grid systems have been tested to separate smaller shrimp. The escape of juvenile red seabream through separating panels made with steel grids or large mesh tested for masking effects in a two-species system. Fish behavior was observed in a circulating water tank. The escape rate was 20% greater with the separating codends than with the normal codend in the single-species experiments. The rates in the two-species experiments were 30% or 20% greater than the single-species rates for the normal or separating codends, respectively. The seabream retention rates in the grid separator codend decreased as rockfish retention increased, possibly due to a threat effect. Conversely, the retention rate of both species increased concurrently in the net separator, possibly due to a masking effect. The escape rates of juvenile red seabream varied by compartment in the mesh separating codend. These results suggest that grid separating codends can be used in the field as towed fishing gear to reduce juvenile catch.