Fumonisins B1 and B2 in Agricultural Products Consumed in South Korea: An Exposure Assessment

SEO, EUNKYOUNG,YOON, YOHAN,KIM, KYEONGYEOL,SHIM, WON-BO,KUZMINA, NINA,OH, KEUM-SOON,LEE, JONG-OK,KIM, DONG-SUL,SUH, JUNGHYUCK,LEE, SOO-HYUNG,CHUNG, KEE-HEY,CHUNG, DUCK-HWA International Association for Food Protection 2009 Journal of food protection Vol.72 No.2

<P>To survey fumonisins B1 (FB1) and B2 (FB2) in agricultural products consumed in South Korea and provide an exposure assessment, ground samples were extracted (80% MeOH), filtered (0.2 μm), and cleaned up. After evaporation, dry residues were reconstituted in 50% MeOH, and a 50-μl aliquot of this sample was mixed with 200 μl of o-phthaldialdehyde for derivatization. The derivatives were analyzed with a high-performance liquid chromatography system equipped with a fluorescence detector. For validation of the detection procedure, linearity, accuracy, precision, detection limit, and quantification limit were determined. The validated detection method was then used to survey fumonisins in white rice, brown rice, barley, barley tea, beer, wheat flour, millet, dried corn, corn flour, corn tea, canned corn, popcorn, and breakfast cereal. Retention times for FB1 and FB2 standards were 7 and 18 min, respectively. Linearity (R2 = 0.99995 to 0.99998), accuracy (81.47 to 108.83%), precision (2.35 to 5.77), detection limit (25 ng/g or ng/ml), and quantification limit (37 ng/g or ng/ml) indicated that this procedure is capable of quantifying fumonisins in agricultural products. Only FB1-positive samples (5.12%, three dried corn samples and five corn flour samples) were found at 90.89 to 439.67 ng/g. According the survey results, an estimated daily intake of FB1 and FB2 in Korea was 0.087 ng/kg of body weight per day. These results indicate that continuous monitoring of these mycotoxins is necessary to establish appropriate risk assessment, and the maximum tolerable daily intake of fumonisins in Korea is lower than the 2 μg/kg set by the Joint Food and Agriculture Organization-World Health Organization Expert Committee.</P>

특목고 진학계획의 사교육비 지출에 대한 인과효과 분석

서은경(Seo, Eunkyoung),김현철(Kim, Hyunchul),황수진(Hwang, Sujin),이철원(Lee, Cheolwon) 한국교육학회 2018 敎育學硏究 Vol.56 No.2

본 연구에서는 서울교육종단연구(SELS)의 4차 년도부터 6차 년도까지 자료를 활용하여 특목고 진 학계획의 사교육비 지출에 대한 인과효과의 실재를 분석하였다. 특히, 벌점화 회귀모형을 사용하여 특목고 진학계획과 수학 및 영어 사교육비에 영향을 미치는 사전 공변량을 탐색하였고, 선택된 공변 량을 고려한 경향점수를 추정하였다. 역확률가중치방법을 활용하여 선택편의를 조정한 후에 특목고 진학계획의 사교육비 지출에 대한 평균처치효과(ATE)를 추정하였다. 연구의 결과는 중학생의 특목고 진학계획 집단과 일반고 진학계획 집단 간에 사전 공변량을 동등 화한 이후에 특목고 진학계획의 영어 사교육비 지출에 대한 인과효과는 존재하지 않는 것으로 나타 났고, 수학 사교육비 지출은 동등화 이전보다 감소했지만 특목고 진학계획의 수학 사교육비 지출에 대한 인과관계가 존재하는 것으로 나타났다. 또한, 부모의 경제적․교육적 지원이 학생의 고교진학계 획과 사교육 참여에 대한 직접적인 변수인 동시에 매개변수로도 작용하고 있는 것을 확인하였으며, 특목고 진학계획의 사교육비 지출 인과효과에 대한 분석에서 공변량의 동등성 확보 중요성이 논의되 었다 The purpose of this study is to analyze the reality of the causal effect of application plan to special high schools on private tutoring expenditure using data from 4th to 6th year of Seoul Education Longitudinal Study(SELS). In particular, we use a penalty regression model to find out the pre-covariates which affects the application plan to special high schools, math and English private tutoring expenditure, and estimate the propensity score considering the selected covariates. After adjusting the selection bias using the inverse probability weighting(IPWT) method, we estimated the average treatment effect(ATE) of the application plan to special high schools on private tutoring expenditure. The result of the study shows that there is no causal effect of the application plan to special high schools on private tutoring expenditure for English after balancing pre-covariates between special high school planning group and general high school planning group. But there is a causal relationship on the private tutoring expenditure for mathematics. In addition, it was confirmed that parents economic and educational support was confirmed as a direct variable to the student s high school application plan and participation in private tutoring, as well as working as a mediator variable. We also discussed the importance of balancing of pre-covariates in the analysis of causality effect of the application plan to special high schools 목차

Electrofluorescence switching of tetrazine-modified TiO2 nanoparticles.

Seo, Seogjae,Allain, Cl?mence,Na, Jongbeom,Kim, Sehwan,Yang, Xu,Park, Chihyun,Malinge, J?r?my,Audebert, Pierre,Kim, Eunkyoung RSC Pub 2013 Nanoscale Vol.5 No.16

<P>Highly fluorescent tetrazine-modified TiO2 nanoparticles were prepared by the reaction of triethoxysilane-appended chloroalkoxy tetrazine (ESTZ) with TiO2 nanoparticles through a condensation reaction between the surface hydroxyl groups of an electrode and the silane anchor group of ESTZ. The prepared electrodes were used as robust fluorescent layers for electrochemical fluorescence switching (electrofluorochromism) applications in the presence of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) as a charge balancing mediator. The stable charge balancing mediator, TEMPO, in the electrolyte was found to be essential to reduce the intrinsic electron transport resistance of TiO2 in order to achieve reversible electrofluorescence switching. Furthermore it facilitated a fully reversible electrochemical reaction and provided a sufficient charge balance, which allowed us to realize semiconductor-based electrofluorescence switching with an on/off ratio of 4.0 and cyclability greater than 100 cycles.</P>

White Electrofluorescence Switching from Electrochemically Convertible Yellow Fluorescent Dyad

Seo, Seogjae,Kim, Yuna,Zhou, Qing,Clavier, Gilles,Audebert, Pierre,Kim, Eunkyoung WILEY‐VCH Verlag 2012 Advanced Functional Materials Vol.22 No.17

<P><B>Abstract</B></P><P>A fluorescent naphthalimide‐tetrazine dyad (NITZ) was examined for electrofluorochromism. The reversible electrochemistry of the tetrazine was accompanied by the fluorescence change through a quasi‐complete energy transfer in an electrochemical cell prepared by the mixture of polymer electrolyte and naphthalimide‐tetrazine dyad. Owing to the energy transfer within the dyad (naphthalimide and tetrazine), the fluorescence efficiency of NITZ was much enhanced and the effective fluorophore concentration in this system was much less than other tetrazine based electrofluorochromic device (EFD). Thus the yellow fluorescence of NITZ was switched on and off remarkably even with small quantity of NITZ (1 wt.%) in an EFD upon application of step potentials for different redox state. Furthermore, multi‐color fluorescence switching was achieved by blending a naphthalimide to the electrofluorochromic layer, to show white‐blue‐dark state of fluorescence. Since the tetrazine and naphthalimide units have their emission quenched at different potentials, the emission color could be tuned by quenching emission at selected wavelengths, reversibly, under low working potentials.</P>

Improving Educational Dialog System for Historical World Affairs

Eunkyoung Jo,Jungyun Seo 한국응용언어학회 2021 응용 언어학 Vol.37 No.Special

This study aims to introduce the process of developing a dialog system to inform users of historical world affairs. It further aims to show the process of improving the dialog system by expanding the users’ question phrases to expose the contents maximally. The dialog system’s contents contain testimonial talks made by Korean comfort women survivors of Japanese army sexual slavery during World War II. We built a dialog system to design interactions between a user and video-recorded testimonies. In the dialog system, a user is able to interact with them verbally and virtually. The system plays the role of the survivors, who underwent painful experiences during the period. In this dialog system—of which knowledge content for testimonial answers is limited—it is more important to maximally cover the prepared answers than emulate dynamic conversation, which many dialog application researchers have focused on so far to let dialogs have sequentially diverse. Therefore, we expanded question phrases using lexical relatedness and various modal expressions, thereby boosting the content coverage. Overall, this study aims to seek a digital way of representing a dialog on historical world affairs with limited contents.

Basic Research on Responsive Webpage consequent on IT Device

EunKyoung Kim,Eunji Seo,JinSook Lee 한국색채학회 2017 AIC 2017 Jeju Vol.2017 No.10

A responsive Web is the one, in which Web resolution, and layout, etc. are fluidly converted according to the screen environment of a device, and it provides a Webpage optimized to all PCs and Smart devices through one webpage address. With the steady increase in the utilization rate of an IT device, there is a need to do research on a responsive Web reflecting the present real condition of its development. Accordingly, this study conducted the affective evaluation of the visibility of the layout space changing according to a device environment, and the level of harmony consequent on color, and the evaluation results are as follows: 1) As a result of the awareness survey of a responsive Webpage, it was found that the subjects at large were not well acquainted with the IT device environment consequent on a responsive Webpage and layout types. Nevertheless, it was found that they perceived a Webpage change consequent on IT devices as necessary. 2) As a result of factor analysis, visibility was analyzed to be the most important in evaluating a Web. 3) As a result of Float Map analysis, generally, B color was analyzed to be the best in visibility, and the most harmonious in all IT devices, whereas G color was analyzed to be lower in visibility, and more inharmonious in comparison with R & B color.

대화 시스템에서의 조응어 해석

조은경(Eunkyoung Jo),서정연(Jungyun Seo) 한국정보과학회 언어공학연구회 2004 한국정보과학회 언어공학연구회 학술발표 논문집 Vol.16 No.1

조응어 해석(Anaphora Resolution)은 여러 응용 분야에 적절히 적용됨으로써 자연어 이해에서의 양적, 질적 향상을 가져 올 수 있다. 구어에서 조응어(anaphor)는 화자와 청자간에 공유된 정보를 간략하게 나타내는 형태이다. 특히, 구어를 주된 사용 언어로 하는 대화 시스템에서의 조응어의 양상을 살피고 해석하는 문제는 인간과 기계간의 의사소통(man-machine communication)을 온전히 하는 과제이다. 이 논문에서는 인간과 기계간의 대화 시스템(man-machine dialogue system)에서 흔히 쓰일 수 있는 조응 표현에 중점을 두어 그 유형을 살피고 해석의 방식을 제시하도록 한다.

국내 버스터미널의 재실자밀도 기준 정립을 위한 실측조사 연구

서동구(Seo, Donggoo),황은경(Hwang, Eunkyoung) 한국방재학회 2020 한국방재학회논문집 Vol.20 No.5

건축물의 화재안전설계 및 평가를 위해 피난용량을 산정하는 것에 있어서 재실자밀도 기준은 주요한 역할을 한다. 국내의 버스터미널은 불특정인이 이용하는 건축물로서 화재안전측면에서 매우 중요한 건축물임에 불구하고 국내 재실자밀도 기준은 부재하다. 이에 본 연구에서는 버스터미널에 대한 재실자밀도 기준을 정립을 위한 기초자료 구축을 목적으로 서울특별시에 위치한 버스터미널을 실측조사를 PCS를 이용하여 표본조사를 수행하였다. 조사는 대기공간과 통행공간으로 분류하여 조사하였으며 그 결과 대기공간의 평균 재실자밀도는 2.36 m²/pers, 통행공간은 9.48 m²로 나타났다. 또한 국내 설계기준에서 LOS등급으로 살펴보면 대기공간은 B등급 이상, 통행공간은 A등급 이상으로 도출되었다. 조사된 결과를 국내외 재실자밀도 기준으로 살펴보면 대기공간과 통행공간 모두 기준 범위에 수용될 수 있는 결과로 나타났다. 하지만 기준으로 활용되기 위해서는 보다 다양한 유형의 조사가 요구되며 전문가들과의 활발한 협의가 필요할 것으로 판단된다. Occupant load density standards serve an important role when calculating evacuation capacities for fire safety designs and building safety evaluations. Domestic bus terminals are typical examples of buildings that are used by large numbers of people but do not have domestic occupant loaddensity standards despite their importance in terms of fire safety. Therefore, this work presents the results of a sample survey using the People Counting System (PCS) by surveying bus terminals in Seoul, Korea to build the basic data required to establish occupant load density standards for bus terminals. The survey categorized the space within the terminals into waiting and walking zones; the average occupant load density for the waiting zones was found to be 2.36 m²/person, whereas that for the walking zones was 9.48 m²/person. Furthermore, with reference to the Level of Standard (LOS) for domestic designs, the waiting zones should be at level B or higher and walking zones should be at level A or higher. Survey results based on domestic and international occupant load density standards also show that the observed results for both waiting and walking zones in this study are acceptable with respect to all available standards. However, further research and active discussions between experts are required before these standards can be applied practically.

국내 산업전시장에 대한 재실인원 실측조사 및 재실자밀도 기준 적정성에 관한 연구

서동구(Seo, Donggoo),황은경(Hwang, Eunkyoung) 한국방재학회 2019 한국방재학회논문집 Vol.19 No.7

본 연구는 산업전시장에 있어서 재실인원을 무인계수시스템을 이용하여 실측조사함으로써 현재 재실자밀도 기준에 대한 적정성을 확인하고 성능위주 피난안전설계의 기초자료를 확보하는 목적을 갖고 있다. 이를 위해 산업전시장에 대하여 9개월 동안 조사를 실시하여 전시유형에 따른 재실자밀도의 수준을 조사하였다. 전시유형을 2가지로 분류하여 육아전시회의 최대 재실자밀도는 6.3 ㎡/인으로 도출되었고 일반전시회는 6.1 ㎡/인으로 유사한 결과가 도출되었다. 한편 빈도수는 2가지의 유형이 차이를 보였으며 육아전시회의 경우가 최댓값에 가까운 재실자밀도를 나타냈다. 또한 국내외 재실자밀도 기준에 대하여 조사한 결과(0.45~2.8 ㎡/인), 실측조사와는 다소 차이가 있는 것으로 확인하였다. This study aimed to obtain the basic data for performance-based evacuation safety designs by surveying the occupant numbers in an exhibition hall using the people counting system (PCS) and to verify the adequacy of the current criteria for occupant load density. To this end, we conducted a nine-month long survey on the exhibition hall to investigate occupant load densities according to the exhibition type. The exhibitions were categorized into two types. The maximum occupant load density of a nurturer exhibition was 6.3 m²/person while that of a general exhibition was 6.1 m²/person. Thus, the maximum occupant load density values were similar for the two types. However, there was a difference in frequency between the two types such that the nurturer exhibitionshowed the occupant load density close to the maximum value. In addition, a slight difference between the results of investigating the occupant load density criteria (0.45-2.8 m²/person, according to building codes such as IBC, BS, and NZBC) and the results of the actual survey was verified.

결정 트리를 이용한 지시 표현 ‘것’의 구별

조은경(Eunkyoung Jo),김학수(Harksoo Kim),서정연(Jungyun Seo) 한국정보과학회 2007 정보과학회논문지 : 소프트웨어 및 응용 Vol.34 No.9

지시 표현 ‘것’은 한국어 대화에서 자주 등장하는 표현이지만, 그 자체로서 대명사나 한정 명사구와 같은 지시 표현이 아니고, 비지시적인 표현으로 쓰이는 ‘것’과 구별되지 못했기 때문에 지시 해석(reference resolution)에 관한 기존 연구에서 제대로 다루어지지 못했다. 이러한 문제를 해결하기 위해 ‘것’이 가지고 있는 언어학적 속성과 담화 상의 속성을 기반으로 하여 자질 집합을 설정하고, 결정트리를 이용하여 ‘것’을 구별하는 방법을 제안한다. 이 방법에 의한 시스템은 비지시 표현의 것에 대해 92%, 지시 표현의 것에 대해 82%의 F-measure를 보였으며, 전체적인 분류 성능은 89%였다. 이는 패턴에 따른 규칙을 적용한 분류 성능에 비해 약 15% 가량 향상된 결과이다. Referential expression ‘Geot’ is often occurred in Korean dialogues. However, it has not been properly dealt with by the previous researchers of reference resolution, since it is not by itself the referential expression like pronoun and definite noun phrases, and it has never been discriminated from non-referring ‘geot’. To resolve this problem, we establish a feature set which is based on the linguistic property of ‘geot’ and the discourse property of its text, and propose a method to identify referential ‘geot’ from non-referring ‘geot’ using decision tree. In the experiment, our system achieved the F-measures of 92.3% for non-referring geot and of 82.2% for referential geot and the total classification performance of 89.27%, and outperformed the classification system based on pattern rules.