POD와 DMD를 이용한 와류형 분사기의 극저온 질소 분무 동적 특성 분석

강정석(Jeongseok Kang),성홍계(Hong-Gye Sung),손채훈(Chae Hoon Sohn) 한국추진공학회 2017 한국추진공학회지 Vol.21 No.5

The cryogenic nitrogen spray of a swirl injector has been numerically investigated using three dimensional LES turbulence model to analyze the dynamic characteristics under supercritical condition. To predict the precise nitrogen properties under supercritical condition, SRK equation of state, Chung’s method for viscosity and thermal conductivity and Takahashi’s correlation based on Fuller’s theory for diffusion coefficient are implemented. The complex flow structures due to interaction between flow field and acoustic field are observed inside and outside the injector under supercritical condition. FFT, POD, and DMD techniques are employed to understand the coherent structures. By implementing the FFT, the dominant frequencies are identified inside and outside the injector. The coherent flow structures related to the dominant frequencies are visualized using the POD and DMD techniques. In addition, the DMD provides the damping coefficient which is related with the instability prediction.

차량 틸팅 시험을 이용한 엔진 오일 레벨 평가에 대한 연구

김정석(Jeongseok Kim),채강석(Kangseog Chae),김숭기(Soongkee Kim) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5

The purpose of present study is to investigate the influence of vehicle acceleration such as cornering, braking and acceleration on the engine oil starvation phenomenon of the internal combustion engines. In the starvation condition, oil pressure is not maintained in an engine due to the air entering at the suction pipe inlet. Computer aided analysis is useful to simulate oil movement under the worst case and design can be easily changed based on analysis result, but the analysis can’t consider oil quantity under the real vehicle running condition. Engine bench tilting test is more accurate to evaluate the oil starvation, but it is hard to simulate maximum transient tilt angle. It is important that all tilt stands used to test the engine lubrication system should be capable of achieving tilt speed as close to the vehicle condition as possible since the speed may have an impact on the oil pressure. In the present study, vehicle tilting test is introduced for most effective evaluation on the engine oil starvation phenomenon. Test procedure and result evaluation criteria of the vehicle tilting test are also presented.

Identification of 8-Digit HLA-A, -B, -C, and -DRB1 Allele and Haplotype Frequencies in Koreans Using the One Lambda AllType Next-Generation Sequencing Kit

Choe Wonho,Chae Jeong-Don,Yang John Jeongseok,Hwang Sang-Hyun,Choi Sung-Eun,Oh Heung-Bum 대한진단검사의학회 2021 Annals of Laboratory Medicine Vol.41 No.3

Background: Recent studies have successfully implemented next-generation sequencing (NGS) in HLA typing. We performed HLA NGS in a Korean population to estimate HLA-A, -B, -C, and -DRB1 allele and haplotype frequencies up to an 8-digit resolution, which might be useful for an extended application of HLA results. Methods: A total of 128 samples collected from healthy unrelated Korean adults, previously subjected to Sanger sequencing for 6-digit HLA analysis, were used. NGS was performed for HLA-A, -B, -C, and -DRB1 using the AllType NGS kit (One Lambda, West Hills, CA, USA), Ion Torrent S5 platform (Thermo Fisher Scientific, Waltham, MA, USA), and Type Steam Visual NGS analysis software (One Lambda). Results: Eight HLA alleles showed frequencies of ≥10% in the Korean population, namely, A*24:02:01:01 (19.5%), A*33:03:01 (15.6%), A*02:01:01:01 (14.5%), A*11:01:01:01 (13.3%), B*15:01:01:01 (10.2%), C*01:02:01 (19.9%), C*03:04:01:02 (11.3%), and DRB1*09:01:02 (10.2%). Nine previous 6-digit HLA alleles were further identified as two or more 8-digit HLA alleles. Of these, eight alleles (A*24:02:01, B*35:01:01, B*40:01:02, B*55:02:01, B*58:01:01, C*03:02:02, C*07:02:01, and DRB1*07:01:01) were identified as two 8-digit HLA alleles, and one allele (B*51:01:01) was identified as three 8-digit HLA alleles. The most frequent four-loci haplotype was HLA-A*33:03:01-B*44:03:01:01-C*14: 03-DRB1*13:02:01. Conclusions: We identified 8-digit HLA-A, -B, -C, and -DRB1 allele and haplotype frequencies in a healthy Korean population using NGS. These new data can be used as a representative Korean data for further disease-related HLA type analysis.

The Changes of Blood Glucose Control and Lipid Profiles after Short-Term Smoking Cessation in Healthy Males

SeongSu Lee,JeongSeok Seo,SungRae Kim,JoEun Jeong,BeomWoo Nam,JuYul Lee,HeeJin Lee,Chul Lee,ChangUk Lee,InHo Paik,JeongHo Chae,SookHee Chai,SoonJib Yoo,WangYoun Won,DaiJin Kim 대한신경정신의학회 2011 PSYCHIATRY INVESTIGATION Vol.8 No.2

Objective-Our aim was to evaluate the changes in blood glucose control and lipid profiles after 2-months of smoking cessation in healthy males. Methods-Smoking abstinence was evaluated through self-report and urine cotinine levels. 12 individuals who succeeded in quitting smoking were analyzed. Fasting values of glucose and insulin were used to estimate the β-cell activity and insulin resistance was evaluated using the Homeostasis Model Assessment (HOMA) and Quantitative Insulin Sensitivity Check Index (QUICKI). Results-The data showed that the subjects had a significant increase in weight, body mass index and fasting plasma glucose levels after smoking cessation. The HOMA-Insulin Resistance and the HOMA β-cell function increased significantly (p=0.005, p=0.047 respectively). The QUICKI showed a significant decrease (p=0.005). In addition, the low-density lipoprotein cholesterol levels decreased significantly (p=0.028); however, changes in the high-density lipoprotein cholesterol, the triglyceride and total cholesterol levels were not significant (p=0.284, p=0.445 respectively). Conclusion-During the initial stage of smoking abstinence, insulin resistance increased and insulin sensitivity decreased due to elevated body weight and fat composition. Therefore, it is important to educate individuals that stop smoking about the necessity of weight control during smoking cessation programs.

Secrecy Rate for MISO Rayleigh Fading Channels with Relative Distance of Eavesdropper

Namseok Chang,Chan-Byoung Chae,Jeongseok Ha,Joonhyuk Kang IEEE 2012 IEEE COMMUNICATIONS LETTERS Vol.16 No.9

<P>In this letter, we extend the results of secure transmission with artificial noise over multiple-input single-output (MISO) wiretap channels. There is a case such that the transmitter knows the relative distance of the eavesdropper. That is, it knows the distance from itself to the eavesdropper divided by its distance to the legitimate receiver. The study found that when the transmitter utilizes information about the relative distance of the passive eavesdropper, the system can achieve a significant increase in its secrecy rate. This work may be useful evaluating a secure communication system in where a secure-zone is enforced and is accessible, exclusively, to the legitimate receiver.</P>

가솔린 터보차저 엔진 벤틸레이션 시스템 개발

강혁진(Hyukjin Kang),김정석(Jeongseok Kim),채강석(Kangseog Chae) 한국자동차공학회 2014 한국자동차공학회 학술대회 및 전시회 Vol.2014 No.11

A wide variety of engine ventilation system concepts are used to circulate blow-by gases inside of engine for gasoline engines. For turbocharged gasoline engine, the complexity rises due to additional connection to turbocharger. One difficulty with engine ventilation is that many hardware concepts are possible and do exist in many Automotive companies and the industry does not seem to converge to one best practice regarding type of blow-by control devices and usage of fresh air. This research focus on the systematic comparison for specifications, system characteristics, advantages, and disadvantages of various ventilation system. The purpose of this study is to define important criteria necessary to meet system requirements and to decide the best system architecture of gasoline turbo engines. In order to decide optimal ventilation system for turbocharged gasoline engine, Pugh concept selection matrix is utilized to list the various concepts and evaluate them based on requirement.

Emission Characteristics of Hazardous Air Pollutants in Gas-phase Emitted from Commercial Vehicles Using PEMS on Real-road Driving

Sangwoo Han,Taekho Chung,Jounghwa Kim,Seokjune Seo,Junmin Jeon,Jeongseok Chae,Sungchul Hwang,Munsoo Chon,Junepyo Cha,Jinseok Han 한국도시환경학회 2018 한국도시환경학회지 Vol.18 No.3

PBF방식을 이용한 메탄연소기 제작

노용오(YongOh Noh),라용제(YongJae Ra),손은원(EunWon Son),채명일(MyungIl Chae),김진형(JinHyung Kim),방정석(JeongSeok Bang),이금오(Keum-Oh Lee),임병직(ByungJik Lim),임하영(HaYoung Lim) 한국추진공학회 2022 한국추진공학회 학술대회논문집 Vol.2022 No.11

조직공정성, 보안정책 준수의지, 보안성과 간 구조분석 :경호.보안담당 공무원을 중심으로

채정석 ( Chae¸ Jeong-seok ),김현호 ( Kim¸ Hyun-ho ) 한국융합과학회(구 한국시큐리티융합경영학회) 2020 한국융합과학회지 Vol.9 No.4

연구목적: 본 연구는 조직공정성을 독립변인, 보안정책 준수의지를 매개변인, 보안성과를 종속변인으로 설정하여 각 변인의 인과관계를 규명함으로써 경호·보안담당 공무원의 보안성과를 제고할 수 있는 기초자료를 제공하는데 목적을 두고 있다. 연구방법: 이를 위해 과천·대전·서울·세종 정부청사 소속방호관 130명, 광주·대구·부산고등법원 관내 법원보안관리대 소속 공무원 150명, 국회 의회경호·방호담당관실 소속 공무원 130명을 무선표본추출방법으로 표집하였다. 설문조사를 실시한 총 410개의 자료 중 398개의 설문지를 회수하였으며, 이상치 및 결측치가 포함된 46개의 자료를 제외하고 최종적으로 352개의 자료를 SPSS 25.0과 AMOS 25.0의 통계프로그램을 사용하여 빈도분석, 기술통계분석, 탐색적 요인분석, 신뢰도분석, 상관관계분석, 구조방정식 분석을 실시하였다. 결과: 첫째, 조직공정성은 보안정책 준수의지에 정(+)의 영향을 미쳤다. 둘째, 보안정책 준수의지는 보안성과에 정(+)의 영향을 미쳤다. 셋째, 조직공정성은 보안성과에 영향을 미치지 않았다. 넷째, 조직공정성은 보안정책 준수의지를 완전매개하여 보안성과에 정(+)의 영향을 미쳤다. 결론: 조직공정성은 보안정책 준수의지를 완전매개하여 보안성과에 정(+)의 영향을 미치므로 경호·보안담당 공무원의 보안성과를 제고하기 위해서는 무엇보다 보안정책 준수의지를 높일 수 있는 방안이 필요함을 시사한다. 따라서 행정부 정부청사, 사법부, 입법부 각 기관은 경호·보안담당 공무원의 보안정책 준수의지를 고양하기 위한 인사 가점제도 도입, 주기적인 보안교육 실시 등의 방안을 다양하게 모색하여 이를 적용하여야 할 것이다. Pupose: This research aims to provide basic data to enhance the security performance of the guards and security officials by establishing organizational justice as an independent variable, a parameter of willingness to comply with security policy, and identifying the causal relationship of each variable. Methods: 130 protection officers from Gwacheon, Daejeon, Seoul and Sejong Government Complex, 150 civil servants from the Court Security Management Unit in Gwangju, Daegu and Busan High Court, and 130 civil servants from the National Assembly Security and Protection Office were selected as wireless sampling methods. Of the total 410 data surveyed, 398 questionnaires were retrieved, with the exception of 46 data containing anomalies and missing values, 352 data were finally analyzed in frequency, technical statistical analysis, exploratory factor analysis, reliability analysis, correlation analysis, and structural equation analysis using the statistical programs in SPSS 25.0 and AMOS 25.0. Result: First, organizational justice had a positive effect on the willingness to comply with security policy. Second, the willingness to comply with security policies had a positive impact on security performance. Third, organizational justice did not affect security performance. Fourth, organizational justice has had a positive impact on security performance by fully selling its willingness to comply with security policies. Conclusion: Organizational justice has a positive effect on security performance by completely mediating the will to comply with security policy, so it suggests that above all, measures are needed to enhance the security performance of the security and security officials. Therefore, each government office, judiciary, and legislative body of the administration should seek and apply various measures such as introducing a personnel bonus system and conducting regular security education to enhance the public officials in charge of security and security policies.