압축비 변화가 수소-천연가스 엔진의 배기특성에 미치는 영향

이성원,임기훈,박철웅,최영,김창기,Lee, Sung Won,Lim, Gi Hun,Park, Cheol Woong,Choi, Young,Kim, Chang Gi 대한기계학회 2013 대한기계학회논문집 Vol.37 No.5

본 연구에서는 천연가스 70%, 수소 30%의 조성비를 가진 HCNG연료와 천연가스를 각각 대형천연가스엔진에 공급하여 실험을 수행하였다. 고압축비의 수소-천연가스(HCNG)엔진의 배기특성을 살펴보기 위하여 부분부하조건에서 공기과잉률 변화에 따른 각 연료의 배출가스를 분석하였다. 실험결과 압축비가 증가함에 따라 열효율이 향상되었으며 그로인해 $CO_2$ 배출량은 감소하였다. 낮은 배기가스온도에 의하여 산화가 활발히 이루어지 못해 CO의 배출량이 증가하였다. 동일한 공기과잉률에서 압축비가 증가하면 $NO_x$의 배출량이 증가하였다. 하지만 ${\lambda}$=1.9이상의 영역에서는 MBT 점화시기가 동일해지기 때문에 압축비의 영향을 받지 않았다. This study focused on a heavy-duty natural gas engine fuelled with HCNG (CNG: 70 vol%, hydrogen: 30 vol%) and CNG. To study the emission characteristics of an HCNG engine with high compression ratio, the exhaust gas of CNG and HCNG fuel were analyzed in relation to the change in the compression ratio at the half load condition. The results showed that the thermal efficiency improved with an increase in the compression ratio. Consequently, $CO_2$ emission decreased. CO emission increased with inefficient oxidation due to the low exhaust gas temperature. $NO_x$ emission with high compression ratio was increased at the same excess air ratio condition. However, $NO_x$ emission was not affected by a compression ratio exceeding ${\lambda}$ = 1.9 because of the same MBT timing.

COREA 프로젝트를 위한 검출기 모의실험

이성원,강혜성,Lee, Sung-Won,Kang, Hye-Sung 한국천문학회 2006 天文學論叢 Vol.21 No.2

The COREA (COsmic ray Research and Education Array in Korea) project aims to build a ground array of particle detectors distributed over Korean Peninsular, through collaborations of high school students, educators, and university researchers, in order to study the origin of ultra high energy cosmic rays. COREA array will consist of about 2000 detector stations covering several hundreds of $km^2$ area at its final configuration and detect electrons and muons in extensive air-showers triggered by high energy particles. During the intial phase COREA array will start with a small number of detector stations in Seoul area schools. In this paper, we have studied by Monte Carlo simulations how to select detector sites for optimal detection efficiency for proton triggered air-showers. We considered several model clusters with up to 30 detector stations and calculated the effective number of air-shower events that can be detected per year for each cluster. The greatest detection efficiency is achieved when the mean distance between detector stations of a cluster is comparable to the effective radius of the air-shower of a given proton energy. We find the detection efficiency of a cluster with randomly selected detector sites is comparable to that of clusters with uniform detector spacing. We also considered a hybrid cluster with 60 detector stations that combines a small cluster with ${\Delta}{\iota}{\approx}100m$ and a large cluster with ${Delta}{\iota}{\approx}1km$. We suggest that it can be an ideal configuration for the initial phase study of the COREA project, since it can measure the cosmic rays with a wide range energy, i.e., $10^{16}eV{\leq}E{\leq}10^{19}eV$, with a reasonable detection rate.

썬루프 디플렉터 각도에 따른 썬루프 개구부 주변 유동 특성 연구

이성원,신성룡,최의성,이주완,Lee, Sung Won,Shin, Seongryong,Choi, Eui Sung,Yi, Juwan 한국음향학회 2018 한국음향학회지 Vol.37 No.5

In the present study, flow characteristics and wind noises around the sunroof opening are analyzed variation with panoramic sunroof deflector angle. A mesh deflector is attached to reduce wind noise while a car is driving with the panoramic sunroof opening. A new forward inclined type deflector was invented to improve wind noise. The effect of this new concept of mesh deflector on the open-panoramic flow characteristics and wind noises were studied with CAT (Computer Aided Test) and wind tunnel test, which shows the reduction of open-panoramic wind noises such as sunroof buffeting, sunroof booming, and turbulent noise. Therefore, the forward inclined type deflector can efficiently improve wind noise with the same production cost.

소아 성대결절 : 음성치료 후 음성장애지수를 이용한 장기 추적관찰 결과

이성원,노종렬,최승호,김상윤,남순열,Lee, Sung-Won,Roh, Jong-Ryeol,Choi, Seung-Ho,Kim, Sang-Yoon,Nam, Soon-Yuhl 대한후두음성언어의학회 2006 대한후두음성언어의학회지 Vol.17 No.2

Objectives : The purpose of this paper is to know the efficacy of voice therapy for vocal fold nodules in children. Materials and Methods : Sixty two patients with vocal nodules(46 boys and 16 girls) were retrospectively reviewed. Age ranged from 4 to 15 years with mean age of 8 years. Questionnaire survey was carried out with voice handicap index, at pretherapy and post-therapy(3 months and 5 years after voice therapy). Results : Sixty two percent of the patients showed improvement by voice therapy. Twenty five patients continued education at home after voice therapy, but only eight childrens were included this group in pre-school aged children. Voice handicap index was improved in 3 months and 5 years after voice therapy. In contrast, pre-school children group showed slight aggravation in 5 years, especially in emotional subdomain. Conclusion : Voice therapy is effective primary treatment in children with vocal fold nodules. Different result between preschool aged children and school aged group shows needs for age specific approach of voice therapy.

한 · 중 전통가구 장식의 상징적 의미를 활용한 디자인 연구

이정(Li Jing?Lee),이성원(Lee, Sung Won) 한국디자인문화학회 2018 한국디자인문화학회지 Vol.24 No.3

문양(紋樣)은 각 나라의 역사와 함께 장식성과 의미상징의 두 가지 기능을 가지고 있다. 특히, 한⋅중 전통적 요소에 있어서 가구에 사용되는 문양은 중요한 요소이자 양국의 귀중한 문화자산이다. 본 논문의 목적인 한 · 중 양국의 전통가구 문양의 상징적 의미를 활용한 디자인 연구를 통해 현대 가구 디자인에 있어 전통문양의 새로운 발전 방향과 응용 방안을 제시하고자 하였으며, 양국의 문화와 정서를 이해를 할 수 있는 기초적 자료를 제공하였다. 본 논문의 연구 범위는 한 · 중, 특히 14세기 말부터 20세기 초의 조선 시대와 중국 명 · 청시기 전통가구를 중심으로 전통문양의 조형적 측면과 상징적 의미에 대한 연구이다. 연구 방법으로 첫째, 전문서적, 논문, 인터넷 등 선행연구 자료의 조사, 검토, 비교 분석을 통하여 한 · 중 전통가구(傳統家具)와 문양에 대한 연구를 진행하였으며, 둘째, 문양의 소재와 문양의 상징적 의미 고찰을 통해 한 · 중 전통가구 문양의 공통점과 차이점을 비교 분석하였고, 셋째, 한 · 중 전통가구에 사용된 장식문양의 사례분석과 한 · 중 전통문양의 관련 이론연구를 중심으로 현대 가구 디자인에 있어 전통문양의 활용 방안에 대하여 제시하였다. 본 연구를 통하여 조선 시대와 명 · 청시기 가구의 문양에 대하여 체계적으로 이해하고, 전통문양이 현대가구 디자인에 잘 융화되어, 전통문화의 소중한 문화재로써 전승되기를 기대한다. The pattern has two functions in addition to the history of each country: ornament and semantic symbol. In particular, patterns used in traditional furniture in Korea and Chinese traditional elements are important. It is a valuable cultural asset of both countries. The purpose of this paper is to present a new development direction and application of traditional patterns in contemporary furniture design through the study of design using the symbolic meaning of traditional furniture patterns in both Korea and China. To understand the culture and emotion of both countries To provide the basic data. The research scope of this thesis is the study on the formative aspect and symbolic meaning of traditional patterns in Korea and China, especially in the Joseon dynasty from the end of the 14th century to the beginning of the 20th century and the traditional Chinese furniture. First, research on traditional Korean furniture and patterns was conducted through researches, reviews, and comparative analyzes of previous research materials such as specialized books, papers, and the Internet. Second, the study of the symbolic meaning of materials and patterns in patterns Third, the analysis of the patterns of decorative patterns used in Korean and Chinese traditional furniture and the related theories of Korean and Chinese traditional patterns. The application of the pattern is suggested. Through this study, we will systematically understand the pattern of furniture of Joseon Dynasty and Ming & Qing Dynasties period furniture, and it is expected that traditional patterns will be well integrated into modern furniture design and handed down as a precious cultural property of traditional culture.

유도도장 서비스품질이 성인들의 수련만족과 애호도에 미치는 영향

이성원(Lee, Sung-Won),김보겸(Kim, Bo-Kyoum),공성배(Kong, Seong-Bae),김종길(Kim, Jong-Kil) 한국체육과학회 2013 한국체육과학회지 Vol.22 No.5

This study is to examine the effect of Judo gym service quality on adult trainee’s satisfaction and loyalty. To test this, 273 trainees who were training Judo in Gym located in Seoul, Korea were sampled. Survey data were collected through questionnaires and were analyzed with SPSS 18.0 program. The results of this study based on above methods and procedures were as followings. First conviction and capability sub factors of service quality had significant effect on psychological and physical satisfaction. Responsiveness and sympathy had significant effect on social satisfaction. Second, conviction and capability sub factors of service quality had significant effect on active loyalty, and capability had significant effect on cognitive and attitude loyalty. Third, psychological and physical satisfaction had significant effect on active loyalty, attitude loyalty. psychological and social satisfaction had significant effect on cognitive loyalty.

가솔린 직접분사 인젝터의 분무 특성

이성원(Sung-Won Lee),김영춘(Young-Choon Kim),박성영(Sung-Young Park) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5

Optimum engine performance is obtained when the spray characteristics are matched to the size and geometry of the combustion chamber. Fuel spray characteristics of operating conditions for high pressure multi-hole injector has been studied experimentally. An experimental apparatus has been made to operate high pressure injection system and to visualize spray behavior. Spray visualization has been performed to analyze spray formation, spray cone angle, bent angle, and penetration length. Test result shows that penetration length is greatly influenced by the fuel pressure. Penetration amount is decreased as ambient pressure increased. Spray cone angle is increased as fuel pressure and ambient pressure increased. Bent angle is not influenced by the change of the fuel pressure and ambient pressure. Spray cone angle distribution map is plotted using the experimental data.

암호화 기법을 활용한 사물인터넷 기반의 스마트 도어락 시스템

이성원(Sung-Won Lee),박승민(Seung-Min Park),심귀보(Kwee-Bo Sim) 한국지능시스템학회 2017 한국지능시스템학회논문지 Vol.27 No.1

기존 사물인터넷은 보안성이 취약하기 때문에 정보유출로 인한 재산피해가 일어날 수 있다. 특히 사물인터넷을 기반으로 구축된 스마트 도어락 시스템은 그 피해가 더욱 크게 발생될 수 있다. 본 논문에서는 이러한 문제점을 해결하기 위해 센서에서 발생된 데이터를 조건에 따라 분류하여 Google Cloud Message(GCM)을 통해 사용자의 스마트폰으로 알람 메시지를 전송하였다. 스마트폰 애플리케이션을 통해 실시간으로 영상을 확인할 수 있도록 하였고, TCP/IP 프로토콜을 이용하여 도어락을 제어하였다. 또한 OTP-Based Matrix SEED 알고리즘을 도어락 시스템에 적용하여 보안성을 향상시켰다. Since existing Internet of Things(IoT) is vulnerable, it may cause property damage due to the information leakage. Especially, the smart door lock system built on the IoT can cause more damage. To solve these problems, this paper classify the data generated by the sensor according to the condition and send an alarm message to the user’s smartphone through Google Cloud Message (GCM). We made it possible to check the images in real time through the smartphone application and control the door lock using the TCP / IP protocol. Also, we applied OTP-Based Matrix SEED algorithmo tdoor lock system to improve security.

이슈에 대한 언론의 보도경향 판단과 자신의 찬반, 지각된 여론이 제3자 지각에 미치는 영향에 관한 연구 -전주, 완주 통합을 중심으로-

이성원 ( Sung Won Lee ),최윤규 ( Yoon Kyu Choi ),이균형 ( Kyun Hyung Lee ) 전북대학교 사회과학연구소 2012 지역과 세계 Vol.36 No.2

This study examines the impact of three variables in Jeonju-Wanju integration issue from a third-person perception perspective. We selected ``estimate of media coverage patterns``, ``respondents`` pros and cons`, ``perceived public opinion`` as a representative of message variables, respondents` variables and comparative others` respectively. ``Jeonju-Wanju integration`` was our regional pending issue at the time, so we limited media coverage to the regional newspapers and regional TV news coverage. Survey was conducted on 13th~15th July, by trained interviewer in Wanju-Gun where yeas and nays are considered to be similar. Results of survey using quota sample of 250 Wanju respondents show that all three variables have significant influence on the size of the third-person perception. The more respondents think that local media`s news coverage patterns are friendly to the integration, the smaller was the size of the third-person perception. The more respondents agree with the integration, the smaller was the size of the third-person perception. The more perceived public opinion is favorable to the integration, the smaller was the size of the third-person perception. And the more the estimate of media coverage patterns are similar with the respondents` pros and cons, the smaller was the size of the third-person perception. This study examined three kinds of variables in a integrative perspective for the first time, and we can understand the formation process of the third-person perception more precisely and systematically.

등가 S-N 선도 모형에서의 굴착기 연료탱크 마운팅부 내구수명 예측 신뢰성 향상 방안 연구

이성원(Sung-Won Lee),정진욱(Jin-Wook Jeong),김성재(Seong-Jae Kim) 한국기계가공학회 2021 한국기계가공학회지 Vol.20 No.5

It is challenging to estimate the fatigue life of construction equipment consisting of a welded joint using field structure test owing to the uncertainty of the S-N curve. IIW recommends different S-N curves for various welded joint types. However, there is no way to define an appropriate curve considering complex design shape and strain gauge characteristics. This paper proposes an equivalent S-N curve method based on the relationship between IIW effective notch stress and virtual stress using finite element analysis. Moreover, a case study was conducted for the excavator fuel tank. The proposed method is expected to enhance accuracy and consistency in calculating the fatigue life for the welded structure of construction equipment.