http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
금속 자기기억법 활용 보일러 튜브의 미소 결함 검출력 연구
서정석,명주홍,방지예,정계조,Jungseok, Seo,Joohong, Myong,Jiye, Bang,Gyejo, Jung 한국전력공사 2022 KEPCO Journal on electric power and energy Vol.8 No.2
The boiler tubes of thermal power plants are exposed to harsh environment of high temperature and high pressure, and the deterioration state of materials rapidly increases. In particular, parent material and welds of the materials used are subjected to a temperature change and various constraints, resulting in deformation and its growth, resulting in frequent leakage accidents caused by tube failure. The power plant checks the integrity of boiler tubes through non-destructive testing as it may act as huge costs loss and limitation of power supply during power station shutdown period due to boiler tube leakage. However, the current non-destructive testing is extremely limited in the field to detect micro cracks. In this study, the ability of metal magnetic memory technique to detect flaws of size that are difficult to inspect by the visual or general non-destructive methods was verified in the early stage of their occurrence.
서정석(Seo, Jungseok),김정섭(Kim, jeongseob) 한국측량학회 2021 한국측량학회 학술대회자료집 Vol.2021 No.11
2017년 포항 지진이 발생한 뒤 소비심리가 감소하는 등 지역상권이 침체되는 현상이 발생하였다. 그러나 회복 탄력성(resilience) 관점에서 2017 포항 지진으로 인한 지역상권의 침체정도와 회복정도가 지역특성에 따라 어떻게 다른지 실증분석은 거의 진행되지 않은 실정이다. 따라서 본 연구에서는 업종별 창·폐업 자료를 활용하여 지역상권의 침체정도와 회복속도가 지역상권별로 어떤 특징을 가지는지 살펴보고자 한다. 즉 포항 지진 전·후 창·폐업 추세를 시·공간적으로 살펴봄으로써 창업 활동이 줄어드는 지역과 폐업 활동이 증가하는 지역의 지역 특성을 도출하고자 한다. 연구 결과, 지진으로 인한 영향은 창업활동보다 폐업 활동에 더 큰 영향을 미쳤으며 특히 소매업의 폐업이 지진 발생 이후 더 가속화되었음을 확인하였다. 본 연구는 포항 지진으로 인해 지역 상권 침체가 지역 특성별로 어떻게 다른지 실증분석을 통해 알아보았다는 점에서 의의를 지닌다. 특히, 2017년에 발생한 포항 지진은 우리나라 지진 역사상 유례가 없는 피해를 발생하였다. 따라서 이러한 재난에 회복 탄력적인 상권의 특성이 무엇인지 살펴보는 것은 추후 재난관리 측면에서 중요하다.
부동산 뉴스와 주택경기의 동적 관계에 대한 고찰 : 언론보도논조지수 개발을 중심으로
서정석(Seo, Jungseok),오지훈(Oh, Jihun),김정섭(Kim, Jeongseob) 한국지역개발학회 2021 韓國地域開發學會誌 Vol.33 No.1
It is well known that news can affect the psychological factor and sustain the housing bubble by framing specific information about the housing market. The news reports about real estate market could affect an expectation of housing consumers which is one of the significant factors to explain housing market trends. To explore the relationship among housing market news, consumers sentiment, and market trends, we develop a Media Tone Index based on housing news articles collected from the online portal site. We apply text-mining techniques to quantify the tones of news articles related to the housing market. Then, we conduct time-series analysis such as Autoregressive Distributed Lag and Error Correction (ARDL-EC) models to analyze the dynamic relationship between the Media Tone Index and housing market trends in South Korea. As a result, we identify similar time-series trends between the Media Tone index and consumers sentiment. Moreover, when the housing market was on a downtrend, news articles tone tended to become positive. The relationship between the Media Tone Index and other housing market variables identified in this study could provide a better understanding of housing market dynamics both in the short- and long-term.
부가질량과 Nonhomogeneous 베어링 지지 조건이 고려된 로터 킷의 진동해석 모델
정종탁(JongTak Jeong),서정석(JungSeok Seo),송오섭(Ohseop Song) 한국소음진동공학회 2018 한국소음진동공학회 논문집 Vol.28 No.4
In this study, a refined structural model of a complex rotating shaft system with nonuniform cross-section, disks, and supported by several bearings are established via Hamilton’s variational principle. Timoshenko beam theory is adopted to incorporate transverse shear and the rotary inertia effect. It is assumed that the shaft spins with a constant speed about its spin axis and is subjected to a conservative axial force. Elastic coupling between vertical and lateral bending motion is caused by Coriolis acceleration. The implications of the gyroscopic effect, additional masses, axial force, and nonhomogeneous boundary conditions (reflecting bearing stiffness and damping) are revealed and analytical results are compared with those obtained from the ANSYS finite element analysis. The prediction model established in this study could be used for the preliminary design of a complicated rotating system.
머신러닝 기반 아파트 주동형상 자동 판별 모형 개발 및 적용 - 주동형상에 따른 아파트 개발 특성분석을 중심으로 -
한상욱 ( Sanguk Han ),서정석 ( Jungseok Seo ),( Sri Utami Purwaningati ),오지훈 ( Jihun Oh ),김정섭 ( Jeongseob Kim ) 한국지리정보학회 2023 한국지리정보학회지 Vol.26 No.2
This study aims to develop a model that can automatically identify the rooftop shape of apartment buildings using GIS and machine learning algorithms, and apply it to analyze the relationship between rooftop shape and characteristics of apartment complexes. A database of rooftop data for each building in an apartment complex was constructed using geospatial data, and individual buildings within each complex were classified into flat type, tower type, and mixed types using the random forest algorithm. In addition, the relationship between the proportion of rooftop shapes, development density, height, and other characteristics of apartment complexes was analyzed to propose the potential application of geospatial information in the real estate field. This study is expected to serve as a basic research on AI-based building type classification and to be utilized in various spatial and real estate analyses.
송오섭(OhSeop Song),박상윤(Sangyun Park),강성환(Sunghwan Kang),서정석(Jungseok Seo),김선홍(Sunhong Kim) 한국소음진동공학회 2013 한국소음진동공학회 학술대회논문집 Vol.2013 No.10
This paper contains various vibration analysis of multi-stage shaft shape such as the bending, torsional and axial vibration.The shaft system is modeled as Timoshenko beam with the transverse shear and rotary inertia effect and the equation of motion is derived by Hamilton’s principle with considering clamped-free boundary condition. Then, eigenvalue problem of discrete equation of motion for multi-stage shaft model is solved and got results of the natural frequency through the numerical analysis. Obtained numerical analysis results through Matlab program were compared with those of FEM analysis to verify the results. This study suggests that design of shaft system be consider torsional and axial vibration as well as bending vibration.