비타민 C의 방사선에 의한 간독성 완화 효과

안기정(Kijung Ahn),박성광(Sungkwang Park),조흥래(Heunglae Cho),강기문(Kimun Kang),정덕화(Duckwha Chung),강진순(Jinsoon Kang),채규영(Gyuyoung Chai) 대한방사선종양학회 2004 Radiation Oncology Journal Vol.22 No.4

목 적: 본 연구는 방사선에 의한 간 손상에 대한 비타민 C의 보호 효과를 알아보기 위해서 시행되었다. 대상 및 방법: Sprague Dawley 실험 쥐를 대조군, 방사선 조사군, 방사선 조사 후 비타민 C 투여군, 3그룹으로 나누어 각 그룹에 무작위로 6마리를 분배하여 실험을 진행하였다. 비타민 C의 항산화 효과를 알아보기 위해서 Superoxide dismutase (SOD), 카탈라제, Malondialdehyde (MDA), 간 효소를 측정하고 그 값을 비교하였다. 결 과: 방사선에 의해서 증가된 MDA 수치와 감소된 SOD 활성도 및 카탈라제의 활성도는 비타민 C 투여로 개선되었으나 통계적 유의성은 없었다. GOT, GPT, LDH, ALP 수치들은 방사선 조사로 증가되었으나 비타민 C 투여로 감소하는 것을 관찰할 수 있었으며, GPT의 경우에는 통계적으로 유의하게 감소하였다. 전자 현미경 소견에서도 간세포 구조의 손상 정도가 비타민 C 투여군에서 뚜렷하게 감소하는 것을 관찰할 수 있었다.결 론: 비타민 C는 방사선에 의한 간세포 손상에 대해서 비록 통계적 유의성은 없었으나 항산화 효과를 보였다. Purpose: This study was carried out to determine the protective effects of vitamin C on the hepatotoxicity induced by radiation. Materials and Methods: The Spraque Dawley rats were randomly divided into 3 groups; the control group, the radiation exposed group, and the radiation and vitamin C-treated group. SOD activity, catalase, malondialdehyde and liver enzymes were analyzed to assess the antioxidant effects of vitamin C. Results: The increased level of malondialdehyde and the decreased catalase activity that were induced by radiation were improved after vitamin C but there was no statistical significance among three groups. The superoxide dismutase activity of the liver was increased by vitamin C, but there were no statistically significant differences between the vitamin C-treated group and the non vitamin C-treated group. The level of liver enzymes in sera such as glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, lactate dehyrogenase and alkaline phosphatase were remarkably elevated by radiation. The levels of those enzymes were decreased in the vitamin C-treated group and statistical significance was noted for the GPT level (p<0.01). On the electromicrographic findings, the hepatic cell destruction was considerably decreased in the vitamin C-treated group. Conclusion: Vitamin C is thought to be an effective antioxidant against the hepatotoxicity induced by radiation.

A Study on the Performance Analysis of MILITARY Culture Innovation

Kijung Kim,Wonseok Kang J-INSTITUTE 2021 International Journal of Military Affairs Vol.6 No.1

Purpose: This study was conducted to evaluate and analyze whether the military culture innovation, which has been being promoted since 2014, is doing well through a survey of Army soldiers on "A Survey on the Feelings of Military Culture Innovation." In particular, a qualitative performance analysis of military culture innovation was conducted through a survey on the awareness and satisfaction of soldiers who are experiencing military culture innovation in personally. Method: In this work, we selected suitable questions for the study through factor analysis of the SPSS program and conducted the study in two main ways on selected questions. The first is to conduct an analysis of the performance of military culture innovation through the average of the selected detailed questions for each part on the five implementations of military culture innovation. Second, we divided the officers and soldiers among the survey respondents to see if the results of their survey on the level of military culture innovation showed a difference, and analyzed whether the difference was significant through the SPSS program's independent sample T test. Results: The results of the analysis conducted using selected questions through factor analysis are as follows: First, as a result of the analysis of the feeling of military culture innovation, we produced positive results that we are "somewhat satisfied" with all five implementations. Second, there was a significant difference between the officer group and the soldier group in terms of the sense of military culture innovation. Conclusion: This study was conducted using the most survey results among the performance analysis of mili-tary culture innovation that has ever been done, so the reliability is very high. In addition, it is of great value in that it analyzed quality performance based on the feelings and thoughts of soldiers who are experiencing military culture innovation directly, not performance analysis relying on quantitative results. Through this, we hope that it will help to accurately diagnose the current military culture innovation and find constructive improvements in the future.

AISS4CIR : 전화 상담원을 위한 자율형 정보 지원 시스템

윤기정 ( Kijung Yun ),강연경 ( Yeonkyeong Kang ),이건수 ( Keonsoo Lee ) 한국정보처리학회 2019 한국정보처리학회 학술대회논문집 Vol.26 No.2

전화 상담 과정에서, 상담원은 고객의 요청에 적절히 대응해야 하는 의무를 갖고 있지만, 고객의 요청은 상담원의 수보 범위를 자주 벗어난다. 그런 범위 이외의 질문과 요청에 대해서도 일단은 성실히 응대하는 것이 상담원의 역할이고, 이 부분에서 상담 업무의 어려움이 존재한다. 이러한 어려움을 해결하기 위해서, 상담원에게 고객의 요청을 응대하기 위해 필요한 정보를 실시간으로 제공해줄 수 있는 시스템이 필요하다. 본 연구는, 이상의 기능을 수행하기 위한 시스템 구조를 설계하고, 그 프로토타입을 구현하는 것으로 이루어졌다.

Highly β-Selective Cyclopolymerization of 1,6-Heptadiynes and Ring-Closing Enyne Metathesis Reaction Using Grubbs <i>Z</i>-Selective Catalyst: Unprecedented Regioselectivity for Ru-Based Catalysts

Jung, Kijung,Kang, Eun-Hye,Sohn, Jeong-Hun,Choi, Tae-Lim American Chemical Society 2016 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.138 No.35

<P>It is well-known that Ru-based Grubbs catalysts undergo a highly selective alpha-addition to alkynes to promote exo-cyclization during ring-closing enyne metathesis (RCEYM) or to produce conjugated polyenes containing five-membered rings during the cyclopolymerization (CP) of 1,6-heptadiynes. There are a few reports of beta-selective addition to alkynes using Schrock catalysts based on Mo but none for readily accessible and easy-to-use Ru-based catalysts. We report the first example of beta-selective addition to alkynes using Grubbs Z-selective catalyst, which produces only endo products during the RCEYM reaction of terminal enynes and promotes the CP of 1,6-heptadiyne derivatives to give conjugated polyenes containing a six-membered ring as a major repeat unit. This unique preference for beta-selectivity originated from the side-bound approach of alkynes to the catalyst, where the steric hindrance between the chelating N-heterocyclic carbene ligand of the catalyst and the alkynes disfavored alpha-addition. To enhance the beta-selectivity for CP further, one could increase the size of the substrates on the monomers and lower the reaction temperature to obtain conjugated polyenes containing up to 95% six-membered rings. Moreover, the physical properties of the resulting polymer were analyzed in detail and compared with those of the conjugated polyenes containing only five-membered rings prepared from the same monomer but with a conventional Grubbs catalyst.</P>

데이터센터 냉방 시스템 공랭식 VRF와 수냉식 칠러 열원별 에너지 사용량 시뮬레이션 비교 연구

금기정(Kijung Keum),강윤태(Yountai Kang),황일남(Ilnham Hwang),이재용(Jaeyong Lee),유태진(Taejin Yu) 대한설비공학회 2021 대한설비공학회 학술발표대회논문집 Vol.2021 No.6

As the inverter technology of air-cooled VRF system is developing, the VRF system’s efficiency is improving. The Refrigerant circulating the VRF system can make use of the latent heat, so compared to the coolant of the chiller, the density of the transmitted energy to unit mass is low, and can reduce the conveyance power. Therefore, the VRF system can be the high efficiency system datacenters need. The energy simulation analysis of the air cooled VRF system and the water-cooled chiller system consumes around 9.1% less energy due to its higher efficiency at low partial load conditions.

제조업 근로자에서 직무 스트레스가 자율 신경계 활성도에 미치는 영향

윤기정,하미나,김재용,이상윤,임형준,신애선,황승식,김정수,강대희,조수헌 大韓産業醫學會 2002 대한직업환경의학회지 Vol.14 No.3

목적 : 자율신경계 활성도와 직무 스트레스와의 연관성을 구명하기 위해 본 연구를 수행하였다. 직무 스트레스에 의한 심혈관계 질환 발생의 주요 기전으로 자율 신경계 활성도, 특히 교감신경계의 활성화가 기존의 연구에서 제시되고 이는 바, 이러한 자율신경계 활성도를 생리학적 지표(심박수 변동성; Heart rate variability, HRV) 및 생체시료(요중 카테콜아민)를 이용하여 정량적으로 평가하고 이들의 수준과 직무 스트레스와의 연관성을 구명하는 것을 목적으로 한다. 방법 : 천안시 소재 제조업체의 생산직 남성 근로자 145명을 대상으로 하여 단면연구를 실시하였다. 연구 대상자들은 동일한 근무조건(4조 3교대)로 한정하였다. 직무스트레스는 '직무 만족도 설문조사(Karasek's Job Conten Questionnaire, JCQ)'를 이용하여 평가하였고, 자율신경계 기능은 심박수 변동성과 요중 카테콜아민(에피네프린, 노에피네프린, 도파민)을로 평가하였다. 시료 수집 및 심박수 변동성 측정은 자율신경계의 일주기 리듬을 고려하여 각 연구 대상자들에게 각 교대근무대별로 각각 3회 반복 측정하였다. 직무 만족도 설문조사(49문항)와 함께 인구학적 사항, 직업력, 과거병력, 흡연, 음주력 등에 대한 자기 기입식 설문조사를 시행하였다. 결과 : 직무 만족도 설문조사에 의해 평가된 직무 스트레스 수준을 직무긴장모형(job strain model)에 의한 4개 집단으로 나누었을 때 연구 대상자들은 저긴장 집단(low strain) 24명, 고긴장 집단(high strain) 32명, 수동적 집단 65명, 능동적 집단 20명으로 분포하였다. 직무긴장모형 4개 집단간의 심박수 변동성 및 요중 카테콜아민의 유의한 차이는 없었으며, 심박수 변동성중 특히 심혈관계 질환의 주요 기전으로 제시되는 교감신경계의 활성을 나타내는 저주파 변동성도 4개 집단간에 유의한 차이는 없었다(p-value=0.71). 하지만, 직무기간을 사분위수로 나눈 후 직무 기간이 가장 짧은 군(직무기간<48.5개월, N=28)을 대상으로, 직무긴장모형의 4개 집단간의 저주파 변동성(교감신경 활성도 지시) 차이 비교를 위해 일원분산분석을 시행한 결과 집단-간(between group) 동질성검정이 p-값 0.092의 유의확률을 나타내었다. 결론 : 자율신경계 활성도, 특히 심박수 변동성을 이용한 정량적 평가를 통해 직무 스트레스와의 연관성을 평가한 연구라는 점에서 의의를 지닌다. 제한적이긴 하지만, 근무기간이 짧은 군에서 저긴장 집단과 고긴장 집단간의 저주파 변동성의 차이를 보여 심박수 변동성이 잠재적인 생리적 지표가 될 수 있음을 시사한다. Objective: A cross-sectional study was conducted to evaluate the relationships between autonomic nerve activity (i.e., heart rate variability and urinary catecholamines) and job stress. Methods: The study was conducted on 134 workers from a company producing consumer goods (i.e., diaper, paper towel) located in Cheonan, Korea. Job stress was assessed by Karasek's Job Content Questionnaire (JCQ), Autonomic function was assessed by heart rate variability (HRV) and urinary catecholamines (eponephrine, norepinephrine, and dopamine). Urine samplings, and measurings of HRV, were repeated three times for each shift. Information on demographic characteristics, previous job histories, past medical history, smoking and drinking were also collected. Results: No statistically significant differences were observed in ant HRV and urinary catecholamines among the four groups, which were categorized by the Job Strain Model. When data were stratified by work duration, low field HRV was borderline sigificantly higher in the high strain group in individuals with a sgorter work duration (<48.5 months, N=28, p-value of 0.92 by analysis of variance). Conclusions: Neither HRV nor urinary catecholamines are significantly associated with job stress, as assessed by the Karasek's JCQ. However, HRV seems to be a potential physiological incicator of jov stress only in the workers with a shorter work duration.

Fully Scalable Methods for Distributed Tensor Factorization

Shin, Kijung,Sael, Lee,Kang, U IEEE 2017 IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERIN Vol.29 No.1

<P>Given a high-order large-scale tensor, how can we decompose it into latent factors? Can we process it on commodity computers with limited memory? These questions are closely related to recommender systems, which have modeled rating data not as a matrix but as a tensor to utilize contextual information such as time and location. This increase in the order requires tensor factorization methods scalable with both the order and size of a tensor. In this paper, we propose two distributed tensor factorization methods, CDTF and SALS. Both methods are scalable with all aspects of data and show a trade-off between convergence speed and memory requirements. CDTF, based on coordinate descent, updates one parameter at a time, while SALS generalizes on the number of parameters updated at a time. In our experiments, only our methods factorized a five-order tensor with 1 billion observable entries, 10M mode length, and 1 K rank, while all other state-of-the-art methods failed. Moreover, our methods required several orders of magnitude less memory than their competitors. We implemented our methods on MAPREDUCE with two widely-applicable optimization techniques: local disk caching and greedy row assignment. They speeded up our methods up to 98.2 x and also the competitors up to 5.9 x.</P>

비구형 공간 좌표를 이용한 그래프 뉴럴 네트워크 기반 피질 표면 분할 연구

강동희(Donghee Kang),윤기중(Kijung Yoon) 한국정보과학회 2022 한국정보과학회 학술발표논문집 Vol.2022 No.06

작업장 누적소음 노출과 혈압과의 관련성

이상윤, 김재용*, 임형준, 윤기정, 최홍렬*, 고상백**, 강대희, 조수헌 대한산업의학회 2001 대한직업환경의학회지 Vol.13 No.2

목적 : 작업장에서의 누적소음노출값과 혈압의 변화 사이의 관계를 관찰하기 위한 단면 연구를 시행하였다. 방법 : 소음발생 제조업체의 남성근로자 중 건강진단 자료, 설문지 자료, 인사기록이 모두 갖추어진 852명을 연구대상으로 하였다. 작업장 소음측정값은 34개 지점에서 측정된 작업환경 측정 보고서 값을 사용하였고, 혈압은 건강진단시 측정한 수축기 혈압과 이완기 혈압 각각의 평균을 이용하였다. 가능한 교란변수들을 건강진단시 설문조사를 통하여 조사하였다. 근로자의 근무기간과 근무했던 작업부서의 소음노출값을 이용하여 누적소음노출값을 추정하였고, 이에 따라 전체 연구대상 근로자를 저소음노출군, 중등도소음노출군, 고소음노출군, 과다소음노출군으로 구분하였다. 누적소음노출값으로 구분한 소음노출군 사이에 평균 수축기 혈압 및 이완기 혈압의 차이가 있는 지를 나이, 비만도지수, 혈중 콜레스테롤값, 고혈압의 가족력, 흡연력, 음주력 등의 가능한 교란변수들의 영향을 통제한 상태에서 비교하였다. 결과 : 가능한 교란변수들을 보정한 상태에서 저소음노출군에서 과다소음노출군으로 갈수록 수축기 혈압 및 이완기 혈압의 증가가 있는지를 관찰하기 위해 일반선형모델을 이용하여 분석하였을 때, 수축기 혈압 및 이완기 혈압 모두 소음노출군이 혈압 변화의 유의한 설명변수였고, 수축기 혈압 및 이완기 혈압 모두 저소음노출군에 비해 과다소음노출군이 각각 2.1 mmHg, 2.7 mmHg 만큼 높았다. 결론 : 이는 만성적으로 누적된 고소음에의 노출로 인하여 혈압 상승의 가능성이 있음을 시사한다. Objectives : The association of workplace cumulative noise exposure and blood pressure was investigated in this study using cross-sectional design. Methods : The study population comprised 852 manufacturing male workers of whom occupational health examination data, questionnaire and personnel records were available. Workplace ambient noise monitoring data was used for calculating individual cumulative noise exposure level. Mean of each systolic and diastolic blood pressure of occupational health examination data was used for individual systolic and diastolic blood pressure level. Possible confounding variables including family history of hypertension, smoking habit, alcohol drinking habit were collected by questionnaire. On the basis of job location and duration of work at the location, a cumulatlve time-weighted average noise level was calculated for each workers. According to this cumulative noise exposure level, each study subject was categorized as low noise exposure group, moderate noise exposure group, high noise exposure group, very high noise exposure group. Among noise exposure groups, mean of systolic and diastolic blood pressure was compared after adjusting possible confounding variables such as age, body mass index, serum cholesterol level, family history of hypertension, smoking history, alcohol drinking habit. Results : After adjusting possible confounding variables, noise exposure group was signnificant explanatory variables for both systolic and diastolic blood pressure, and mean of both systolic and diastolic blood pressure of very high exposure group was higher than that of low exposure group. Conclusions : These findings suggested that the high cumulative noise exposure might elevate the blood pressure.

작업장 누적소음 노출과 혈압과의 관련성

이상윤(Sang-Yun Lee),김재용(Jai-Young Kim),임형준(Hyoungjune Im),윤기정(Kijung Yoon),최홍렬(Hongryul Choi),고상백(Sangbaek Koh),강대희(Daehee Kang),조수헌(Soo-Hun Cho) 대한직업환경의학회 2001 대한직업환경의학회지 Vol.13 No.2