• 한국자동차공학회논문집
• /
• 제5권6호
• /
• pp.28-35
• /
• 1997

Occupant injuries are always possible in a rollover accident, one of the major accidents in a bus. Thus the structure of body frame should have sufficient strength to protect passengers under accidental loads,. ECE(Economic Commission for Europe) regulation No.66 prescribes that residual space shall be preserved in the passenger compartment during and after the structure has been subjected to the prescribed rollover test. Rollover test on a bus section was completed according to the regulation. The coordinates of body section before and after rollover were measured, and it was checked that the structure still complied with the requirements of residual space. Direct measurement on a bus is difficult because of its large size. Thus photogrammetry by photographing and 3 dimensional digital modeling was introduced, and the coordinates of each point were measured through this method.

• Membrane and Water Treatment
• /
• 제2권4호
• /
• pp.267-279
• /
• 2011

At steady state, the simultaneous transport of sulphuric acid and nickel sulphate through an anion-exchange membrane Neosepta-AFN (Astom Corporation, Tokyo, Japan) was investigated in a two-compartment counter-current dialyzer with single passes. The transport was quantified by the recovery yield of acid, rejection of salt and four phenomenological coefficients, which were correlated with the acid and salt concentrations in the feed. The phenomenological coefficients were determined by the numerical integration of the basic differential equations describing the concentration profiles of the components in the dialyzer. This integration was combined with an optimizing procedure. The experiments proved that the acid recovery yield is in the limits from 63 to 91 %, while salt rejection is in the limits from 79 to 97 % in the dependence on the volumetric liquid flow rate and composition of the feed.

• 한국화재소방학회논문지
• /
• 제30권5호
• /
• pp.116-123
• /
• 2016

화재모델링을 이용한 목표 대상물의 열적 손상에 대한 정량적 위험성 평가방법이 검토되었다. 이를 위해 대표적인 화재모델로서 FDS가 사용되었으며, 특정 구획 내에서 화원 면적 변화에 따른 전기 케이블의 열적 손상과 관련된 확률이 평가되었다. 보수적 관점에서 적용되고 있는 '최대 손상임계 초과확률'과 손상시간의 정보가 포함된 '손상확률'이 체계적으로 비교되었다. 목표 대상물이 표면온도 및 열유속에 대한 최소 손상기준에 도달하는 순간에 열적 손상이 발생된다는 가정이 적용된 최대 손상임계 초과확률에 비해 본 연구에서 제안된 손상확률은 정량적 화재 위험성을 보다 현실적으로 평가할 수 있음을 확인하였다.

• Toxicological Research
• /
• 제35권4호
• /
• pp.295-301
• /
• 2019

In this review, we describe the absorption rates (Caco-2 cell permeability) and hepatic/plasma pharmacokinetics of 53 diverse chemicals estimated by modeling virtual oral administration in rats. To ensure that a broad range of chemical structures is present among the selected substances, the properties described by 196 chemical descriptors in a chemoinformatics tool were calculated for 50,000 randomly selected molecules in the original chemical space. To allow visualization, the resulting chemical space was projected onto a two-dimensional plane using generative topographic mapping. The calculated absorbance rates of the chemicals based on cell permeability studies were found to be inversely correlated to the no-observed-effect levels for hepatoxicity after oral administration, as obtained from the Hazard Evaluation Support System Integrated Platform in Japan (r = -0.88, p < 0.01, n = 27). The maximum plasma concentrations and the areas under the concentration-time curves (AUC) of a varied selection of chemicals were estimated using two different methods: simple one-compartment models (i.e., high-throughput toxicokinetic models) and simplified physiologically based pharmacokinetic (PBPK) modeling consisting of chemical receptor (gut), metabolizing (liver), and central (main) compartments. The results obtained from the two methods were consistent. Although the maximum concentrations and AUC values of the 53 chemicals roughly correlated in the liver and plasma, inconsistencies were apparent between empirically measured concentrations and the PBPK-modeled levels. The lowest-observed-effect levels and the virtual hepatic AUC values obtained using PBPK models were inversely correlated (r = -0.78, p < 0.05, n = 7). The present simplified PBPK models could estimate the relationships between hepatic/plasma concentrations and oral doses of general chemicals using both forward and reverse dosimetry. These methods are therefore valuable for estimating hepatotoxicity.

• 한국화재소방학회논문지
• /
• 제28권1호
• /
• pp.37-43
• /
• 2014

성능위주 소방설계(PBD)의 과정에서 화재 및 피난모델링의 신뢰성을 확보하기 위해서는 화재감지기 모델의 높은 예측성능이 필수적으로 요구된다. 본 연구의 목적은 대표적인 화재모델인 FDS에 적용되고 있는 정온식 열감지기의 정확한 작동 개시시간을 예측하기 위한 입력정보를 측정하는 것이다. 이를 위해 화재감지기의 장치특성을 측정할 수 있는 Fire Detector Evaluator (FED)가 사용되었으며, 국내에서 적용되는 2개의 써미스터 방식(Thermistor types)과 1개의 바이메탈 방식(Bimetal type)의 스포트형 정온식 열감지기가 연구대상으로 고려되었다. 화재모델링을 위해 요구되는 감지기의 작동 개시온도 및 반응시간지수(Response Time Index)가 측정되었으며, 이때 RTI는 감지기의 설치위치를 고려하여 천장제트기류(Ceiling jet flow)와 수직제트기류(Vertical jet flow)에 대하여 측정되었다. 측정된 장치물성을 이용한 화재모델링 결과는 실규모 구획화재실험 결과와 비교 검증되었다. 그 결과 수치적으로 예측된 감지기의 작동 개시시간은 실험결과를 적절히 잘 예측함을 확인하였다.

• 한국지능시스템학회논문지
• /
• 제12권2호
• /
• pp.157-163
• /
• 2002

본 연구의 목적은 배치 특성의 정량화에 의해 배치 대안들을 비교할 수 있는 객관적인 평가 기준을 정림하는 것이다. 장비배치는 모든 구성 요소들의 기능을 최대로 하고 동시에 공간적인 제한 조건을 만족시키도록 여러 가지 장비들의 위치를 결정하는 설계단계이다. 선박의 경우 설계자가 제시하는 몇 가지 배치안 중 한 가지만 선택하게 되는데 이 과정은 숙련된 전문가의 경험, 지식, 판단에 대한 의존도가 매우 높고 또한, 객관적인 평가가 어렵다. 우리는 이러한 서술적인 언어로 된 것을 퍼지 이론을 통해 정량화하여 배치안을 객관적으로 평가할 수 있는 기준을 제시한다.

• International Journal of Automotive Technology
• /
• 제5권4호
• /
• pp.247-255
• /
• 2004

The majority of real world frontal collisions involves partial overlap (offset) collision, in which only one of the two longitudinal members is used for energy absorption. This leads to dangerous intrusions of the passenger compartment. Excessive intrusion is usually generated on the impacted side causing higher contact injury risk on the occupants compared with full frontal collision. The ideal structure needs to have extendable length when the front-end structure is not capable to absorb crash energy without violating deceleration pulse requirements. A smart structure has been proposed to meet this ideal requirement. The proposed front-end structure consists of two hydraulic cylinders integrated with the front-end longitudinal members of standard vehicles. The work carried out in this paper includes developing and analyzing mathematical models of two different cases representing vehicle-to-vehicle and vehicle-to-barrier in full and offset collisions. By numerical crash simulations, this idea has been evaluated and optimized. It is proven form numerical simulations that the smart structures bring significantly lower intrusions and decelerations. In addition, it is shown that the mathematical models are valid, flexible, and can be used in an effective way to give a quick insight of real life crashes.

• 약학회지
• /
• 제46권1호
• /
• pp.63-68
• /
• 2002

The purpose of this study was to estimate the population pharmacokinetics of clarithromycin in healthy adult Korean and to investigate the factors influencing the pharmacokinetics of clarithromycin. The population pharmacokinetic parameters of clarithromycin were calculated with the data from healthy adult Koreans. A total of 798 plasma concentrations obtained from 78 subjects after administration of a single oral dose of 250 mg or 500 mg were used for the modeling. The concentration-time data were fitted to a one-compartment open model assuming a first-order absorption and elimination with no lag time. The correlations between various factors [such as sex, age, height, weight, sect creatinine (Scr) and dose and pharmacokinetic parameters were estimated with stepwise linear recession analyses. The selected covariates were incorporated in the population model of NONMEM, and the importance of each covariate was investigated by means of backwards elimination. The apparent clearance (CL/F) was significantly correlated to Scr and sex, and the apparent volume of distribution (Vd/F) was significantly correlated to Scr and height in a nonlinear relationship. The population values of Ka was 1.8 h $r_{-1}$, CL/F was 37.71 L/hr, Vd/F was 200 L and t/ sub 1/2 / was 3.68 hrs for a male Korean with 170 m height and 1.0 mg/dL Scr.

• 대한조선학회논문집
• /
• 제43권4호
• /
• pp.451-459
• /
• 2006

When a ship is damaged and flooded, the motion of the damaged ship is significantly influenced by the flooding water dynamics. The flooding water in the damaged ship has been treated as a lumped mass under the quasi-static assumption in most of previous researches. To calculate the motion of damaged ship rigorously, it is necessary to analyze the coupled dynamics of flooding water. In this study, a series of numerical and experimental studies is conducted for the damaged part of ITTC RORO passenger. FLOW3D is used for investigating the feasibility of the state of the art CFD technique. An applicability of the coupled motion analysis of damaged ships can be confirmed by agreement between the numerical results and the model experiments. A CFD technique is considered for the numerical modeling of the dynamics of flooding water.

• 한국ITS학회 논문지
• /
• 제11권1호
• /
• pp.53-65
• /
• 2012

최근 차량내 무선통신이 자동차 산업에서 큰 관심을 받고 있으며 UWB 기술이 차량내 통신 시스템에 유력한 기술로 고려되고 있다. 차량내 통신 채널의 측정과 모델링에 대한 많은 연구가 이루어져 왔으나, 차량내 통신환경에서 다양한 PHY Layer 기술에 대한 성능 분석은 여전히 많은 관심의 대상이 되고 있다. 본 논문의 목적은 차량내 채널환경에서 IEEE 802.15.4a PHY 시스템의 성능을 분석함에 있다. 새시와 엔진 부분의 채널 모델을 설정하고, 동기식 및 비동기식 수신기의 성능을 시뮬레이션을 통하여 분석하였다.