• Journal of Korean Society for Atmospheric Environment
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• v.15 no.5
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• pp.625-638
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• 1999

Air quality modeling for coastal urban region has been composed of a complex system including meteorological, chemical and physical processes and emission characteristics in complex terrain. In this study, we studied about an effect prediction for deposition phenomenon affecting on air quality in Pusan metopolitan metropolitan city. In air quality modeling including ship sources, a situation considered deposition process habe better result than not considered when compared with observed value. Air pollutants emitted into urban air during the daytime nearly removed through urban atmosphere polluted. Also these phenomena correlated concentration variation connent with sea/land breezes and terrain effect. Therefore we conclude that the concentration was low at daytime when deposition flux is high, and deposition effect on industrial complex and Dongrae region is considerable in particular.

• Journal of Nutrition and Health
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• v.33 no.4
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• pp.429-437
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• 2000

Contributions of specific foods to absolute intake and between-person variance in 13 nutrients were examined to develop a short food frequency questionnaire (FFQ) for the Korean elderly using dietary data collected by a semiquantitative FFQ with 96 food items. The contributions of specific foods to 90% absolute nutrient intake were measured by assessing their percentage to the total consumption of a nutrient by our samples(n=98). To assess the contribution of the foods to the between-person variance in intake of each specific nutrient, stepwise multiple regression was performed. Cumulative R2 served as the measure of contribution to variation in intake. The most important food source of absolute intake was rice for energy and protein. Important foods of between person variance contribution include bread for energy and pork for protein. Important foods of absolute and variance contribution of nutrient intake were similar for fat(noodles including jajangmyun and kalguksu), calcium(anchovy and milk) and vitamin A (carrot). The number of foods necessary to account for the variation in nutrient intake among older people in Korea differ considerably by nutrient: 18 - 43 and 8-26 foods were accounted for the respective 90 and 80% of absolute intake depending on nutrients. Carbohydrates and vitamin A and C had relatively a few major sources, thus may be assessed well by a small number of foods. Conversely, iron, potassium and B vitamins appear to need longer lists of foods. Fewer numbeer (6 - 12 and 4 - 9) of foods were required for the corresponding percentages of between-person variation for all nutrients. Depending on nutrients, 0.980-0.995 and 0.924-0.987 were respective correlation coefficients of nutrient intakes measured by 96 food items with those by lists of foods for 90% and 80% of absolute intake contribution. These findings suggest that an incomplete food list on the basis of its contribution to absolute and between person variation intakes may still be effective in discriminating among individuals. The results of this study may be useful in the design and use of dietary questionnaire.

• Journal of Environmental Health Sciences
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• v.47 no.1
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• pp.36-44
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• 2021

Objectives: The study aims to examine the variation over roughly the past 10 years (from 2008 to 2018) in the estimated daily dietary Pb intake (Pb-D) based on the variations of daily intake amount and Pb content in respective food groups. The following factors were considered: (1) variation of estimated value of Pb-D, (2) Pb contents in each food group and (3) the most influential food group for dietary Pb intake. Methods: Estimated values of Pb-D were taken from food consumption by the food groups reported in the Korean National Health and Nutrition Survey and the Pb content of each food group as reported in 19 previous publications. Variation from 2008 to 2018 of Pb intake was calculated from daily intake amount and Pb content in each food group. Results: The survey showed that main Pb intake sources were the food groups 'meats and poultry' and 'fish and shellfish'. These food groups showed gradually increased Pb exposure from 2008 to 2018. Estimated daily Pb intake was 42.18 to 57.68 ㎍/day for men and 30.97 to 42.54 ㎍/day for women. Both men and women showed slightly increased dietary Pb intake from 2008 to 2018. The food groups 'meats and poultry' and 'fish and shellfish' proved the highest Pb intake food groups. Estimated Pb intake from 'meats and poultry' was 8.47 to 12.98 ㎍/day and that of 'fish and shellfish' was 5.63 to 10.10 ㎍/day. Conclusion: Over the past ten years, daily Pb intake has slightly increased in men and women. The food groups 'meats and poultry' and 'fish and shellfish' might be the main variation factors of Pb intake.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.82-82
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• 2014

One of the subjects in clouds' structure and development is small scale structure of interstellar cloud. The possibility of AU scale structure (Marscher et al. 1993; Moore & Marscher 1995; Roy et al. 2012) is discussed, and this small scale structure is considered as the result of hydrogen volume density (Moore & Marscher 1995), or small-scale chemical and other inhomogeneities (Liszt & Lucas 2000). In order to study this subject with emission line, extremely high resolution is mandatory by VLBI system. However, the alternative method could be observing the absorption line of interstellar cloud on the continuum object. In this case, the resolution would be restricted to the size of the continuum object, if the size of the object is smaller than the resolution of a used telescope. We observed the previous researchers' three objects (BLLAC, NRAO150, B0528+138), whose spectrums are changed from 1993 to 1998 (Liszt & Lucas 2000), with KVN. Through KVN observation, we found the changes of optical depth spectrum compared with the previous spectrums. We will discuss the optical depth spectrum variation by time variation and the meaning of it.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1991.10a
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• pp.29-32
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• 1991

It is well known that the fatigue damage process in composite materials is very complicated due to complex failure mechanisms that comprise debounding, matrix cracking, delamination and fiber splitting of laminates. Therefore, the residual strength, instead of a single dominant crack length, is chosen to describe the criticality of the damage accumulated in the sublaminate. In this study, two models for residual strength degradation established by Yang-Liu and Tanimoto-Ishikawa that are capable of predicting the statistical distribution of both fatigue life and residual strength have been investigated and compared. Statistical methodologies for fatigue life prediction of composite materials have frequently been adopted. However, these are usually based on a simplified probabilistic approach considering only the variation of fatigue test data. The main object of this work is to propose a fatigue reliability analysis model which accounts for the effect of all sources of variation such as fabrication and workmanship, error in the fatigue model, load itself, etc. The proposed model is examined using the previous experimental data of GFRP and it is shown that it can be practically applied for fatigue problems in composite materials.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.302-305
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• 2007

During the CareBeijing campaign in September 2006, Imaging Differential Optical Absorption Spectroscopy (IDOAS) measurements were made over the city of Beijing, China using a spatial resolution of 146 pixels horizontally and 61 pixels vertically, each with a field of view of $0.133^{\circ}$ and $0.072^{\circ}$ in the horizontal and vertical directions, respectively. Using Fraunhofer reference spectra (FRS) for the evaluation of data for two consecutive days, the diurnal variation of $NO_2$ distributions was determined from data measured every single hour from 08:00 until 16:00 on September 9 and 10. Both days presented a fairly clear sky with high visibility. The setup allowed detailed images of the low surface $NO_2$ distribution over Beijing. Images with less than a 30-min temporal resolution showed variation of plume dispersal in both horizontal and vertical directions. An in-situ measurement was also conducted. Results from both instruments are interpreted by considering local emission sources and wind conditions.

• Journal of The Korean Astronomical Society
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• v.43 no.6
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• pp.201-211
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• 2010

We present an analysis of the measurements of mid-eclipse times of V839 Oph, collected from literature sources. Our analysis indicates a period increase of $3.2{\times}10^{-7}$ day/yr. This period increase of V839 Oph can be interpreted in terms of mass transfer of rate $1.76{\times}10^{-7}M_{\odot}/yr$, from the less to the more massive component. The O - C diagram shows a damping sine wave covering two different complete cycles of 36.73 yr and 19.93 yr with amplitudes approximately equal to 0.0080 and 0.0043 day, respectively. The third cycle has to be expected to cover about 13.5 years with lower amplitude than those of the former two cycles. These unequal duration cycles show a non periodicity which may be explained as resulting from either the presence of a tertiary component to the system or cyclic magnetic activity variations due to star spots. For the later mechanism, the obtained characteristics are consistent when applying Applegate (1992) mechanism.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.05a
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• pp.349-352
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• 2004

Twelve strains of Lactobacillus acidophilus isolated from feces of human or animal sources were tested for probiotic properties such as cholesterol assimilation, bile and acid tolerances, and CLA production. Although the cultures showed some variation with respect to each test, the 12 strains could be classified into 3 groups based on their ability to assimilate cholesterol. The cholesterol assimilation showed positive correlation with bile tolerance and negative correlation with acid tolerance. The cholesterol assimilation of L. acidophilus strains may not be related to the deconjugation activity, but may in fact be attributed to its bile tolerance. CLA production by lactic acid bacteria (LAB) exhibited a wide variation that ranged from 2.69 to 7.64 mg/g fat. CLA production of Bifidobacterium longum ATCC 15707 was the highest among the LAB tested, but there was no evidence for differences in CLA production between genus and species.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1435-1440
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• 2009

Geotechnical variability is a complex feature that results from many independent sources of uncertainties, and is mainly affected by inherent variability and measurement errors. This study evaluates the coefficient of variation (COV) of soil properties at Song-do region in Korea for evaluating inherent soil variability. Since soil variability is sensitive to soil layers and soil types, the COVs by soil layers (reclaimed layer and marine layer) and the COVs by soil types (clay and silt) were separately evaluated. It is observed that geotechnical variability of marine layer and clay is relatively smaller than that of reclamation layer and silt.

• Structural Engineering and Mechanics
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• v.83 no.5
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• pp.577-591
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• 2022

This paper develops a comparatively time-efficient methodology for performing seismic fragility analysis of the reinforced concrete (RC) buildings in the presence of uncertainty sources. It aims to appraise the effectiveness of any variation in the material's mechanical properties as epistemic uncertainty, and the record-to-record variation as aleatory uncertainty in structural response. In this respect, the fuzzy set theory, a well-known 𝛼-cut approach, and the Genetic Algorithm (GA) assess the median of collapse fragility curves as a fuzzy response. GA is requisite for searching the maxima and minima of the objective function (median fragility herein) in each membership degree, 𝛼. As this is a complicated and time-consuming process, the authors propose utilizing the Gene Expression Programming-based (GEP-based) equation for reducing the computational analysis time of the case study building significantly. The results indicate that the proposed structural analysis algorithm on the derived GEP model is able to compute the fuzzy median fragility about 33.3% faster, with errors less than 1%.