• Journal of Korean Society for Atmospheric Environment
• /
• v.23 no.5
• /
• pp.515-525
• /
• 2007

In this study, various techniques for measurement and analysis of PAHs in the ambient air were verified in order to select a more reliable method. Sampling and analysis of PAHs were done by the EPA TO-13a method. QA/QC of the measurement was conducted to minimize errors in sampling and analyzing processes. The linearity of calibration curve of the PAH standards was good ($R^2{\geq}0.99$). Audit accuracy was evaluated using 5 internal standards of PAHs ($Naphthalene-d_8,\;Acenaphthene-d_{10},\;Phenanthrene-d_{10},\;Chrysene-d_{12},\;Perylene-d_{12}$). Relative standard deviations of the internal standard of the PAHs were ranged from 6.22% for $acenaphthene-d_{10}$ to 8.11% for $chrysene-d_{12}$. To evaluate the surrogate recoveries, two field surrogate standards of PAHs ($fluoranthene-d_{10},\;benzo(a)pyrene-d_{12}$) and two extract surrogate standards of the PAHs ($fluorene-d_{10},\;pyrene-d_{12}$) were spiked into all samples before field sampling and sample extraction, respectively. Recoveries of field the surrogate standards ranged from $80.4{\pm}12.2%$ for $fluoranthene-d_{10}$ to $66.2{\pm}12.8%$ for $benzo(a)pyrene-d_{12}$. Extraction recoveries of the surrogate standards ranged from $70.4{\pm}10.2%$ for $fluorene-d_{10}$ to $77.6{\pm}10.8%$ for $pyrene-d_{10}$. The detection limit of benzo(a)pyrene among 16 PAHs standards for quantitation was 20 pg.

• Proceedings of the Korean Society of Developmental Biology Conference
• /
• 2005.10a
• /
• pp.82-83
• /
• 2005

• Proceedings of the Korean Society of Embryo Transfer Conference
• /
• 2005.10a
• /
• pp.82-83
• /
• 2005

• Management Science and Financial Engineering
• /
• v.8 no.2
• /
• pp.21-31
• /
• 2002

In this paper, we explore a new class of cutting planes by extending the concept of fractional S-K (S-K) cuts. This class of cuts is derived by applying a suitable surrogate constraint analysis that incorporates a special multiplier adjustment method to the generalized Gomory's fractional cut. We present computational results to provide insights into the performance of these cuts in comparison with other well known classes of cuts.

• Journal of the Korean Data and Information Science Society
• /
• v.24 no.6
• /
• pp.1543-1550
• /
• 2013

In this paper, we study Bayesian estimation for the finite population proportion in binary data under selection bias. We use a Bayesian nonignorable selection model to accommodate the selection mechanism. We compare four possible estimators of the finite population proportions based on data analysis as well as Monte Carlo simulation. It turns out that nonignorable selection model might be useful for weekly biased samples.

• Management Science and Financial Engineering
• /
• v.18 no.2
• /
• pp.13-17
• /
• 2012

Set covering has widely been accepted as a staple tool for feature selection in data mining. We present a generalized version of this classical combinatorial optimization model to make it better suited for the purpose and propose a surrogate relaxation-based procedure for its meta-heuristic solution. Mathematically and also numerically with experiments on 25 set covering instances, we demonstrate the utility of the proposed model and the proposed solution method.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.10c
• /
• pp.304-306
• /
• 2000

내장형 디바이스를 인터넷과 연결하고자 하는 요구가 늘어나고 있다. 이러한 정보기기들을 동적으로 상호 작용하게 하는 기술로서 지니(Jini)가 최근 주목을 받고 있다. 그러나 내장형 디바이스에서 지니 서비스를 제공하기 위해 요구되는 높은 하드웨어 사양이 문제점으로 지적되고 있다. 본 논문에서는 이러한 non-Java 디바이스를 지니 네트워크에 접속하여 지니 서비스를 제공할 수 있도록 서로게이트 시스템(Surrogate System)과 non-Java 디바이스간의 프로토콜을 설계하였다.

• Journal of Korean Institute of Industrial Engineers
• /
• v.27 no.2
• /
• pp.135-139
• /
• 2001

A process control procedure is suggested when screening inspection is performed with a surrogate variable correlated with the performance variable. Assuming bivariate normal distribution for the performance and screening variable, the procedure is designed on the basis of the time required for detecting process shift.

• Journal of the Korea Society of Computer and Information
• /
• v.20 no.3
• /
• pp.97-106
• /
• 2015

In this paper, the development of infrared threat surrogate system is described and it can be used to verify the performance of DIRCM system. In this research, threat surrogates are manufactured using same F# and reflective optics used in 1st- and 2nd-Gen. real seeker so that the threat surrogate system can be used to develop code-based jamming techniques. Also the threat surrogate system can analyze the saturation jamming effect for image seeker using FPA detector. The result shows that 1st- and 2nd-generation threat surrogates have relatively precise tracking performance and jamming effect.

• Journal of Soil and Groundwater Environment
• /
• v.24 no.6
• /
• pp.16-25
• /
• 2019

Anthropogenic polycyclic aromatic hydrocarbons (PAHs) are formed by the incomplete combustion of fuels and industrial waste. PAHs can be widely exposed to the environment (water, soil and groundwater). PAHs are potentially toxic, mutagenic and/or carcinogenic. Fundamental studies such as biota uptake (e.g., earthworm and plant) of PAHs are highly needed. It is necessary to develop alternative ways to evaluate bioavailability of PAHs instead of using living organisms because it is time-consuming, difficult to apply in the field, and also exaction method is tedious and time-consuming. In this study, sorption behaviors of phenanthrene were evaluated to predict the fate of PAHs in soils. Moreover, bioaccumulation of PAHs in an artificially contaminated soil was evaluated using pea plant (Pisum sativum) as a bioindicator. A novel passive sampler, organic-diffusive gradient in thin-film (o-DGT) for PAHs was newly synthesized, tested as a biomimic surrogate and compared with plant accumulation. Sorption partitioning coefficient (K_P) and sorption capacity (K_F) were in the order of natural soil > loess corresponding to the increase in organic carbon content (f_oc). Biota-to-soil accumulation factor (BSAF) and DGT-to-soil accumulation factor (DSAF) were evaluated. o-DGT uptake was linearly correlated with pea plant uptake of phenanthrene in contaminated soil (R²=0.863). The Tenax TA based o-DGT as a biomimic surrogate can be used for the prediction of pea plant uptake of phenanthrene in contaminated soil.