• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제3권3호
• /
• pp.143-150
• /
• 1999

Mobile source emissions are important inputs to photochemical air quality models. Since most mobile source emissions are calculated at the county-level, these emission should be geographically allocated to the computational grid cells of a photochemical air quality model prior to running the model. The traditional method for the spatial allocation of these emissions has been to use a "spatial surrogate indicator" such as population, since grid-specific emission calculations are very labor-intensive and expensive, plus the necessary data are often not available for such grid resolutions. Accordingly, new spatial surrogate indicators for mobile source emissions(specifically for highway emissions) were developed using Geographic Information Systems(GIS) tools due to the spatially variable nature of mobile source emissions. These newly developed spatial surrogate indicators appear to be more appropriate for the allocation of highway emissions than the population surrogate indicator. It was also revealed that the conventional spatial allocation method underestimates the maximum levels of air pollutant emmissions.mmissions.

• 대한가정학회지
• /
• 제49권9호
• /
• pp.73-81
• /
• 2011

The purpose of this study was to find out how price perception and the site's delivery system affected consumer satisfaction in surrogate internet shopping for apparel products. A survey questionnaire was used to collect information from 233 respondents who had experience in purchasing apparel products from online venues within the preceding 6 months. Collected data underwent descriptive analysis, factor analysis, and regression analysis. Results showed that the price perception and the delivery system was influenced by three factors. Both price perception and the delivery system factors showed a significant difference depending on the gender of consumers. Also, according to the regression results, both price perception and the delivery system had a positive effect on consumer satisfaction in surrogate Internet shopping mall for apparel products.

• 품질경영학회지
• /
• 제28권2호
• /
• pp.1-16
• /
• 2000

This paper considers the problem of determining the optimal process mean and screening specification limits of a surrogate variable associated with product quality under two-stage screening procedure. In two-stage screening, the surrogate variable is inspected first to decide whether an item should be accepted, rejected or additional observations should be taken. If additional observations are required, the performance variable of interest is then observed to classify the undecided items. Assuming that the performance variable and the surrogate variable are jointly normally distributed, the optimal process mean and the screening limits are obtained by maximizing the expected profit which includes selling price, production, reprocessing, inspection and penalty costs. A numerical example is presented and numerical studies are performed to compare the proposed two-stage screening procedure with single-stage screening procedures.

• International Journal of Fluid Machinery and Systems
• /
• 제2권2호
• /
• pp.179-188
• /
• 2009

Recent development of high speed computers and use of optimization techniques have given a big momentum of turbomachinery design replacing expensive experimental cost as well as trial and error approaches. The surrogate based optimization techniques being used for aerodynamic turbomachinery designs coupled with Reynolds-averaged Navier-Stokes equations analysis involve single- and multi-objective optimization methods. The objectives commonly tried to improve were adiabatic efficiency, pressure ratio, weight etc. Presently coupling the fluid flow and structural analysis is being tried to find better design in terms of weight, flutter and vibration, and turbine life. The present article reviews the surrogate based optimization techniques used recently in turbomachinery shape optimizations.

• 대한산업공학회지
• /
• 제31권2호
• /
• pp.99-105
• /
• 2005

A quality inspection procedure interchangeably using the performance and surrogate variables is proposed. At the start of the inspection, the continuous performance variable is measured for all items. As soon as iconsecutive items are found to be conforming, the continuous surrogate variable is measured instead of the performance variable. If an item is rejected, the inspection based on the performance variable is resumed. It is assumed that the performance variable and the surrogate variable are jointly normally distributed with known means and standard deviations. The average outgoing quality (AOQ) expression is derived, and the methods of finding the inspection procedure with a specified average outgoing quality limit (AOQL) are presented.

• 한국연소학회지
• /
• 제16권2호
• /
• pp.9-15
• /
• 2011

Homogeneous charge compression ignition(HCCI) is the best concept able to provide low NOx and PM in diesel engine emissions. This new alternative combustion process is mainly controlled by chemical kinetics in comparison with the conventional combustion in internal combustion engine. In this paper, combustion characteristics of HCCI engine with suggested diesel surrogate(heptane/toluene mixture fuel) reaction mechanism were numerically investigated by heptane/toluene mixture ratio and EGR ratio. As results, the ignition timing became faster with increasing of heptane, and an initial oxidation and the ignition timing of the mixture fuel were affected by heptane and toluene, respectively.

• Structural Engineering and Mechanics
• /
• 제71권4호
• /
• pp.329-339
• /
• 2019

Assessment of failure probability, especially for a complex structure, requires a considerable number of calls to the numerical model. Reliability methods have been developed to decrease the computational time. In this approach, the original numerical model is replaced by a surrogate model which is usually explicit and much faster to evaluate. The current paper proposed an efficient reliability method based on Monte Carlo simulation (MCS) and multi-gene genetic programming (MGGP) as a robust variant of genetic programming (GP). GP has been applied in different fields; however, its application to structural reliability has not been tested. The current study investigated the performance of MGGP as a surrogate model in structural reliability problems and compares it with other surrogate models. An adaptive Metropolis algorithm is utilized to obtain the training data with which to build the MGGP model. The failure probability is estimated by combining MCS and MGGP. The efficiency and accuracy of the proposed method were investigated with the help of five numerical examples.

• Nuclear Engineering and Technology
• /
• 제55권8호
• /
• pp.3071-3079
• /
• 2023

Helium production in the nuclear fuel matrix during irradiation plays a critical role in the design and performance of Gen-IV reactor fuel, as it represents a life-limiting factor for the operation of fuel pins. In this work, a surrogate model for the helium production rate in fast reactor MOX fuels is developed, targeting its inclusion in engineering tools such as fuel performance codes. This surrogate model is based on synthetic datasets obtained via the SCIANTIX burnup module. Such datasets are generated using Latin hypercube sampling to cover the range of input parameters (e.g., fuel initial composition, fission rate density, and irradiation time) and exploiting the low computation requirement of the burnup module itself. The surrogate model is verified against the SCIANTIX burnup module results for helium production with satisfactory performance.

• Journal of Veterinary Science
• /
• 제22권1호
• /
• pp.11.1-11.7
• /
• 2021

Background: The spore-forming bacterium Bacillus anthracis causes anthrax, an often-fatal infection in animals. Therefore, a rapid and reliable strategy to decontaminate areas, humans, and livestock from B. anthracis is very critical. Objectives: The aim of this study was performed to evaluate the efficacy of sodium hypochlorite, calcium hypochlorite, and quaternary ammonium compound (QAC) sanitizers, which are commonly used in the food industry, to inhibit spores and vegetative cells of B. anthracis surrogate. Methods: We evaluated the efficacy of sodium hypochlorite, calcium hypochlorite, and a QAC in inhibiting vegetative cells and spores of a B. anthracis surrogate. We treated a 0.1-mL vegetative cell culture or spore solution with 10 mL sanitizer. The samples were serially diluted and cultured. Results: We found that 50 ppm sodium hypochlorite (pH 7), 1 ppm calcium hypochlorite, and 1 ppm QAC completely eliminated the cells in vegetative state. Exposure to 3,000 ppm sodium hypochlorite (pH 7) and 300 ppm calcium hypochlorite significantly eliminated the bacterial spores; however, 50,000 ppm QAC could not eliminate all spores. Conclusions: Calcium hypochlorite and QAC showed better performance than sodium hypochlorite in completely eliminating vegetative cells of B. anthracis surrogate. QAC was ineffective against spores of the B. anthracis surrogate. Among the three commercial disinfectants tested, calcium hypochlorite most effectively eliminated both B. anthracis vegetative cells and spores.

• 사회복지연구
• /
• 제41권4호
• /
• pp.45-79
• /
• 2010

본 연구는 한국사회의 대리모 여성의 심리사회적 고통 체험의 구조를 심층적으로 이해하기 위하여 실행되었다. 자료는 미디어를 통해 수집된 질적 2차 자료를 상호주관적 삶으로서의 역동성과 의미를 잘 나타내주는 파시(Parse)의 현상학적-해석학적 연구방법에 적용하여 분석하였다. 분석 결과 대리모 여성의 체험은 경제적 고통으로 선택한 최선의 대안이었으나 출산과 양육이 분리된 모성은 일방적 관계로의 위험에 노출되나 보상과 입양의 맞물림으로 잊혀 질 모성의 현실을 수용하는 과정이라는 구조로 나타났다. 그러한 구조를 전환시키면 대리모 여성의 체험은 생의 마지막 선택이라 여기나 죄책감과 혼란스러움으로 드러낼 수 없는 존재로서 모성을 도구화하는 것으로 파악되었다. 이러한 해석은 파시의 추상성 높은 개념으로 통합하여 대리모 여성의 체험은 가치화를 가능-제한, 노출-은폐하여 독특성을 강화하고 변형시켜가는 과정으로 재해석 되었다. 대리모 여성에 대한 경제적·의료적·법적 차원에서의 논의와 함의를 다루었다.