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정용재,이창준,Jung, Yong Jae,Lee, Chang Jun 한국화학공학회 2020 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.58 No.2
본 연구에서는 폭발위험장소의 방폭설비 설치를 위해 필요한 가스폭발위험범위 예측모델 개발을 수행하였다. 이를 위해 12개의 가연성가스에 대한 1,200개의 폭발위험범위 데이터를 생성하였다. 가스폭발위험범위를 출력변수로 설정하였고 데이터 생성과정에서 필요한 12개의 변수를 입력변수로 설정하였다. 다중 회귀, 주성분 회귀, 인공신경망 기법을 이용해 예측모델을 개발하였다. 각각 모델의 예측 성능을 비교한 결과, 평균절대퍼센트오차(MAPE)는 각각 44.2%, 49.3%, 5.7%이고 평균제곱근오차(RMSE)는 1.389 m, 1.602 m, 0.203 m로 나타났다. 결과를 통해 인공신경망이 가장 우수한 성능을 보여주었고 가스폭발위험범위 예측을 위한 최적 모델이라는 것을 확인하였다. In this study, predictive models based on machine learning for evaluating the extent of hazardous zone of explosive gases are developed. They are able to provide important guidelines for installing the explosion proof apparatus. 1,200 research data sets including 12 combustible gases and their extents of hazardous zone are generated to train predictive models. The extent of hazardous zone is set to an output variable and 12 variables affecting an output are set as input variables. Multiple linear regression, principal component regression, and artificial neural network are employed to train predictive models. Mean absolute percentage errors of multiple linear regression, principal component regression, and artificial neural network are 44.2%, 49.3%, and 5.7% and root mean square errors are 1.389m, 1.602m, and 0.203 m respectively. Therefore, it can be concluded that the artificial neural network shows the best performance. This model can be easily used to evaluate the extent of hazardous zone for explosive gases.
비폐색성 위 전정부 확장이 있는 흰쥐의 위 수축력, 체중 및 위 형태 복원에 대한 영계출감탕과 보중익기탕(補中益氣湯)의 효능
정용재,윤상협,Jung, Yong-Jae,Yoon, Sang-Hyub 대한한방내과학회 2010 大韓韓方內科學會誌 Vol.31 No.4
Objectives : The aim of this study was to evaluate whether rats with non-obstructive antral dilation could be a useful tool resembling functional dyspeptic patients. We also investigated the effect of Bojoongikki-tang (BJ), and Youngkaechulgam-tang (YK) in antral dilated rats. Methods : Non-obstructive antral dilation was performed by first wrapping a non-absorbable rubber ring (D:6mm, W:4mm, T:1mm) around the 1st portion of the duodenum causing pyloric obstruction (PO). After 12 weeks, except for some PO group rats used for the control, the rubber ring was removed by performing another operation. The antral dilated rats (AD) were then divided into three groups, a non-treatment group (AD-NT), and two herbal medicine groups each given an extract solution containing 125 mg/kg of Youngkaechulgam-tang (AD-YK) or Bojoongikki-tang (AD-BJ) for 4 weeks. Then gastric contractility was evaluated by bowel sound measurement, and afterwards the changes of the weight, and morphologic changes of the stomach were evaluated for each group including the normal intact group (NI). Results : Loss of weight and enlargement of the stomach surface area was seen in the PO group. Decrease of gastric motility index was observed in the AD-NT group, while the increased surface area of the stomach was not significantly different from the PO group. Youngkaechulgam-tang seemed to increase gastric contraction, whereas Bojoongikki-tang showed no effect. Weight gain of rats was observed in both the AD-YK and AD-BJ groups, but there seemed to be no change of the dilated stomach surface area. Conclusions : The non-obstructive antral dilated rat seems to be an experimental pathologic model that reflects the gastric dysmotility similar to functional dyspeptic patients with antral dilation. Therefore patients with dysmotility-like dyspepsia with antral function disorders should be treated efficiently. As Youngkaechulgam-tang is shown to increase both gastric contraction and weight in antral dilated rats, it may be used for treating functional dyspepsia. However, Bojoongikki-tang should be used with caution in patients with gastric dysmotility.
정용재,최정은,이규식,Chung, Yong-jae,Choi, Jung-eun,Lee, Kyu-shik 국립문화재연구소 2007 保存科學硏究 Vol.28 No.-
This project aims to develop a partnership between France and Korea; the field of paper conservation with two mains objectives. The first object is to study the possibilities of implementing the use of traditional Korean paper in conservation workshops in France and Europe. The second one is to establish a long term collaborative research program to investigate the degradation mechanisms of ancient papers and particularly early waxed manuscripts founded in Korea and France which are now brittle and fallen into parts. This problem deserves an investigation using analytical tools such as SEC/MALS, GC/MS to understand the interactions between wax and cellulose during the ageing process and to recommend proper conservation treatment. A research plan could be establish for both institution in order to facilities an exchange of visiting scholars (scientist, post-doc) to implement and share knowledge and for carrying out the research.
인화성액체의 폭발위험장소 설정을 위한 증발율 추정 모델 연구
정용재 ( Yong Jae Jung ),이창준 ( Chang Jun Lee ) 한국안전학회(구 한국산업안전학회) 2018 한국안전학회지 Vol.33 No.4
In many companies handling flammable liquids, explosion-proof electrical equipment have been installed according to the Korean Industrial Standards (KS C IEC 60079-10-1). In these standards, hazardous area for explosive gas atmospheres has to be classified by the evaluation of the evaporation rate of flammable liquid leakage. The evaporation rate is an important factor to determine the zones classification and hazardous area distance. However, there is no systematic method or rule for the estimation of evaporation rate in these standards and the first principle equations of a evaporation rate are very difficult. Thus, it is really hard for industrial workplaces to employ these equations. Thus, this problem can trigger inaccurate results for evaluating evaporation range. In this study, empirical models for estimating an evaporation rate of flammable liquid have been developed to tackle this problem. Throughout the sensitivity analysis of the first principle equations, it can be found that main factors for the evaporation rate are wind speed and temperature and empirical models have to be nonlinear. Polynomial regression is employed to build empirical models. Methanol, benzene, para-xylene and toluene are selected as case studies to verify the accuracy of empirical models.
호흡기 분리형 음압 챔버의 개발과 기도 삽관 시 보호 효과의 확인
정용재 ( Yong Jae Jung ),성기섭 ( Ki Sub Sung ),유지나 ( Gina Yu ),홍주영 ( Ju Young Hong ),정현수 ( Hyun Soo Chung ) 대한응급의학회 2021 대한응급의학회지 Vol.32 No.6
Objective: Within the last 2 years, coronavirus disease 2019 has spread rapidly across several continents, with 100 million confirmed infected patients. Physical barrier enclosure, also called “aerosol-box,” is a solution for the shortage of protective devices and spaces. In this study, we examined the safety of the novel barrier enclosure. Methods: We simulated droplets by nebulizing 1% glycerol+99% ethanol solution. Two experienced physicians performed intubation under two conditions, such as the isolator condition (applying isolator without negative condition) and the negative pressure condition (applying isolator with the negative condition). We compared two conditions with two control groups, including negative control (room air) and positive control (synthetizing droplet air). During the procedure, particles were counted for 30 seconds, and this was repeated 10 times. At each condition, depending on the result of the normality test (Shapiro-Wilk test), an independent t-test was used when normality was satisfied, and a Mann-Whitney Utest was used when normality was not satisfied. Results: The total number of particles in the positive control was 308,788 (175,936-461,124). The total number of particles for both conditions was significantly less than the positive control. Total number of particles in the isolator condition was 30,952 (27,592-33,244, P=0.001) and that in the negative pressure condition was 27,890 (27,165-29,786, P=0.001). Conclusion: The novel barrier significantly reduces synthetizing droplets exposure during intubation. Application of negative pressure through the isolator results in an additional decrease in particle exposure. Studies involving a larger population of operators and prolonged procedures are required.
모바일 환경에서 콘텐츠 보호를 위한 실시간 DMB 암호화 구현
정용재(Yong-Jae Jeong),정태일(Tae-Il Jung),문광석(Kwang-Seok Moon),김종남(Jong-Nam Kim) 한국멀티미디어학회 2008 한국멀티미디어학회 학술발표논문집 Vol.2008 No.2
최근 DMB(digital multimedia broadcasting)의 급속한 보급화는 이동형 DMB 기기의 보급화로 확산되었고, 이러한 이동형 DMB 기기를 통한 불법적인 콘텐츠 배포는 문제가 될 수 있다. 본 논문에서는 이동형 기기를 통한 DMB 콘텐츠의 불법적인 배포를 차단하기 위하여 실시간으로 DMB 콘텐츠를 암호화 방법을 제안하고, 이동형 DMB 기가 중 PMP(portable multimedia player)에 구현한다. 제안한 구현은 DMB 스트림에서 I-frame을 찾아 AES (advanced encryption stnadard) 알고리즘을 사용하여 비트스트림의 크기와 형태의 변화를 주지 않으면서 I-frame전체를 암호화 하였다. 실험결과 100㎒의 동작속도를 가지는 DSP가 내장된 PMP에서 DMB 시청 중 실시간으로 암호화 할 때 암호화에 소비되는 시간지연은 거의 없었고, 암호화된 콘텐츠의 비가성을 시각적으로 확인할 수 있었다. 제안한 방법은 이동형 DMB 단말기에서 DMB 콘텐츠의 불법 배포를 방지하기 위한 콘텐츠 보호용 소프트웨어로 활용 될 수 있을 것이다.