Failure to comply with the performance test requirements for the centrifugal pumps at power plants often results in performance dissatisfaction as a result of field tests. This study proposed a method of reducing the uncertainty of the field test results by evaluating the systematic error in the measurement system caused by failure to follow the test requirements using the computational fluid dynamics(CFD) technique. As a result of the evaluation of the systematic error and reflecting it in the performance test data, it was confirmed that the error occurred at a constant rate with respect to the flowrate and that the pump, which showed a difference in performance actually had the same performance.

Nonlinear analysis for seismic performance evaluation of existing building usually takes 4~5 times more than linear analysis based on KBC code. To obtain accurate results from the nonlinear analysis, there are a lot of things to be considered for nonlinear analysis modeling. For example, reinforcing layout, applied load and seismic details affect behavior of structural members for the existing building. Engineer-oriented computerized system was developed for engineers to evaluate effective seismic performance of existing buildings with abiding by seismic design principles. Using the engineer-oriented program, seismic performance evaluation of reinforced concrete building was performed. Nonlinear hinge properties were applied with real time multiple consideration such as section layout, section analysis result, applied load and performance levels. As a result, the building was evaluated to satisfy LS(Life Safety) performance level. A comparison between engineer-oriented and program-oriented results is presented to show how important the role of structural engineer is for seismic performance evaluation of existing buildings.

Seismic performance evaluation of existing building usually needs much time and man power, especially in case of nonlinear analysis. Many data interaction steps for model transfer are needed and engineers should spend much time with simple works like data entry. Those time-consuming steps could be reduced by applying computerized and automated modules. In this study, computational platform for seismic performance evaluation was made with several computerized modules. StrAuto and floor load transfer module offers a path that can transfer most linear model data to nonlinear analysis model so that engineers can avoid a lot of repetitive work for input information for the nonlinear analysis model. And the new nonlinear property generator also helps to get the nonlinear data easily by importing data from structural design program. To evaluate the effect of developed modules on each stages, seismic performance evaluation of example building was carried out and the lead time was used for the quantitative evaluation.

The purpose of this study is to investigate information on performance of ventilation in high-tech microelectronicscleanrooms using computational fluid dynamics (CFD). One liquid crystal display (LCD) company was examinedfor evaluating the relationship between workplace concentration and ventilation rate efficiency by using CFDsoftware, Airpak 3.0v. Acetone concentration in cleanroom for final packing process, which is inspected LCD was40.1ppm (GSD 1.91) (n=55) as geometric mean, ranged 7.8~128.7ppm and weakly correlated with ventilationrate efficiency (R²=0.37, p<0.01). Resulting from computational fluid dynamics (CFD), acetone concentrationcan be reduced 62% when install booth type local exhaust system, the most efficient way among 10 other differentventilation methods like increasing volume of general ventilation, changing the location of workers, supply orexhaust diffusers and install downstream type local exhaust system, etc. We found that volitile organic compoundsin cleanroom can be a matter of adverse health effects and the concentration was correlated with ventilation rateefficiency. The most optimized plan to control the contaminants in solvent cleaning work in cleanroom was boothtype local exhaust system.

In this study, to investigate an optimal configuration method for the modeling system, we performed an optimization experiment by controlling the types of compilers and libraries, and the number of CPU cores because it was important to provide reliable model data very quickly for the national air quality forecast. We were made up the optimization experiment of twelve according to compilers (PGI and Intel), MPIs (mvapich-2.0, mvapich-2.2, and mpich-3.2) and NetCDF (NetCDF-3.6.3 and NetCDF-4.1.3) and performed wall clock time measurement for the WRF and CMAQ models based on the built computing resources. In the result of the experiment according to the compiler and library type, the performance of the WRF (30 min 30 s) and CMAQ (47 min 22 s) was best when the combination of Intel complier, mavapich-2.0, and NetCDF-3.6.3 was applied. Additionally, in a result of optimization by the number of CPU cores, the WRF model was best performed with 140 cores (five calculation servers), and the CMAQ model with 120 cores ( five calculation servers). While the WRF model demonstrated obvious differences depending on the number of CPU cores rather than the types of compilers and libraries, CMAQ model demonstrated the biggest differences on the combination of compilers and libraries.

Nonlinear seismic evaluation of RC building usually needs much time and man power, In this study, several computational modules were applied for evaluation of existing RC buildings. To investigate the effect of applied modules on time, seismic performance evaluation of example building was performed and the man power input was compared with conventional process.

본 연구는 일반 X선 검사에서 CR 시스템을 이용한 환자의 근사적 피폭 선량을 평가할 수 있는 실험적 모델을 제시하고 저선량 영역에서 의료 피폭에 대한 방어의 최적화 조건으로 환자의 선량 권고량(diagnostic reference level.DRL)을 비교하고자 하였다. 이를 위하여 기준선량계와 광자극발광선량계(optically stimulated luminescencedosimeters. OSLDs)를 이용하여 관전압(kVp) 및 관전류‧노출시간의 곱(mAs)에 따른 입사표면선량(entrance surface dose. ESD)을 교차 측정하였으며 CR 시스템에서 각 노출 조건에 대한 Hounsfield unit (HU) scale을 측정하여 ESD와 HU 스케일에 대한 특성 관계를 이용하여 근사적 피폭 선량을 구하였다. 또한 임상적으로 적용 가능한지를알기 위하여 두부, 경부, 흉부, 복부, 골반부 노출 조건으로 물 팬텀에 모사하여 피폭 선량을 구하였다. 결과적으로 두선량계의 평균 ESD는 각각 2.10, 2.01, 1.13, 2.97, 1.95 mGy 이었으며 CR 영상에서 측정한 HU 스케일은 각각 3,276±3.72, 3,217±2.93, 2,768±3.13, 3,782±5.19, 2,318±4.64 이었다. 이 때 ESD와 HU 스케일에 대한 특성 관계를 이용하여 근사적으로 구한 ESD는 각각 2.16, 2.06, 1.19, 3.05, 2.07 mGy이었으며 평균 측정값과 근사적으로 구한 ESD의 오차는 3% 미만으로 영상의학 분야의 측정 오차 5%를 감안한다면 신뢰할 수 있는 오차 범위라 할 수 있었다.결론적으로 CR 시스템을 이용한 일반 X선 검사에서 환자의 피폭 선량을 근사적으로 평가할 수 있는 새로운 실험적 모델을 제시하였으며 CR 검사뿐 만 아니라 디지털 방사선촬영(digital radiography. DR) 시스템 및 필름-증감지 시스템에 적용 가능할 것으로 판단되었다.