Long working hours and risk of hypothyroidism in healthy workers: a cohort study

Lee Yesung,Lee Woncheol,김형렬 한국역학회 2022 Epidemiology and Health Vol.44 No.-

OBJECTIVES: Long working hours have been reported to cause various health problems. However, long working hours are currently practiced in many countries. To confirm the consistency with a previous study, the authors aimed to elucidate the causal relationship between long working hours and hypothyroidism through a longitudinal study. METHODS: Data was collected at baseline from 45,259 participants without thyroid disease and with no change in groups of weekly working hours, which were categorized into 36–40, 41–52, 53–60, and > 60 hours, during follow-up period. Hypothyroidism was defined using the reference limits of serum thyroid-stimulating hormone and free thyroxine levels. By estimating hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox proportional hazards regression analyses, the risk of incident hypothyroidism was evaluated with weekly working 36–40 hours as the reference. RESULTS: During 138,261.7 person-years of follow-up, 2,914 participants developed hypothyroidism (incidence density, 2.11 per 102 person-years). Multivariable-adjusted HRs of incident hypothyroidism for weekly working 41–52, 53–60, and > 60 hours compared with the reference group were 1.13 (95% CI 1.03–1.24), 2.53 (95% CI, 2.17–2.95), and 2.57 (95% CI, 2.09– 3.15), respectively. In dose-response analyses, long working hours had an approximately linear relationship with the incidence of hypothyroidism. The risk of incident hypothyroidism in weekly working 53–60 and > 60 hours compared with the reference group were significantly higher among the older age group (≥ 36 years, stratified by median age), men, and daytime workers. CONCLUSIONS: This large-scale cohort study demonstrated the association between long working hours and the increased risk of incident hypothyroidism with a dose-response relationship.

Ferrite-Cored Patch Antenna With Suppressed Harmonic Radiation

Lee, Woncheol,Hong, Yang-Ki,Choi, Minyeong,Won, Hoyun,Lee, Jaejin,Park, Seong-Ook,Bae, Seok,Yoon, Hwan-Sik Institute of Electrical and Electronics Engineers 2018 IEEE Transactions on Antennas and Propagation Vol. No.

<P>We designed and fabricated a multiple-ferrite-cored patch antenna (MFC-PA) to suppress harmonic radiation over the frequency range of 1–10 GHz and obtain wide suppressing bandwidth. Its suppression performance was compared to those of the conventional PA, photonic bandgap PA (PBG-PA), and defected ground structure PA (DGS-PA). Simulated and measured results show that MFC-PA effectively suppresses harmonic radiation up to <TEX>$5.6f_{0}$</TEX>, where <TEX>$f_{0}$</TEX> is 0.9 GHz, while the harmonic radiation of PBG-PA and DGS-PA is suppressed up to <TEX>$3f_{0}$</TEX>. It is suggested by the antenna performance simulation that MFC-PA can further suppress harmonic radiation up to <TEX>$11f_{0}$</TEX>. In principle, the harmonic radiation of MFC-PA is suppressed by dissipating the unwanted signals in ferrite materials, whereas PBG-PA and DGS-PA suppress harmonic radiation by reflecting or redirecting unwanted signals, which is not desired. Ferrite loading is a unique approach to suppress any harmonic radiation.</P>

The Effects of Bidens frondosa Interference on Soybean Planted at Different Plant Densities

Woncheol Lee,Ji-Ae Yu,Sumin Han,Soo-Hyun Lim,Yeon-Ho Park,Do-Soon Kim 한국잡초학회 2023 한국잡초학회 별책(학술대회 초록집) Vol.43 No.1

심리변인을 융합한 상황인지 모델링 및 서비스 활용방안

이원철(Woncheol Lee),김연희(Yeonhee Kim) 한국HCI학회 2014 한국HCI학회 학술대회 Vol.2014 No.2

센서 및 하드웨어, 소프트웨어 그리고 통신기술의 융합적인 발달에 힘입어 전에 없던 새로운 문화가 생겨났다. 특히, 스마트기기라 불리고 있는 전화기, 태블릿 PC, 웨어러블 디바이스 등은 다양한 기술이 응집된 인공물로써 인간과 인간, 인간과 사물 그리고 사물과 사물을 끊김없이 연결하고, 정보를 주고받으면서 인간을 둘러싸고 있는 환경과 그에 반응하는 인간 행위의 특징을 체계적으로 분석하기 시작했다. 하지만 지금까지의 상황인지 서비스는 하드웨어 및 통신기술의 한계로 인해 많은 제약이 있었으며 물리적인 데이터 수집에만 그쳤기에 다양한 상황에 처해진 인간의 내면과 그에 따른 행동의 다양성을 제대로 이해하지 못했다. 따라서 본 연구는 인간의 독특한 반응패턴을 추론할 수 있는 대표적 요인인 성격을 6 요인 성격모델 Hexaco 를 통해 분석하고, 각기 다른 상황에 배치된 저전력 블루투스(bluetooth low energy) 기반의 비콘(beacon)을 통해, 성격유형 별 차별화된 상황인지 서비스를 제공하고자 하며 이를 통해 개인의 심리적 요인이 반영된 한층 더 발전된 형태의 상황인지 모델을 제시하고자 한다. Sensors and hardware, software, and communication technologies never before thanks to developmental fusion of the new culture is born. In particular, various techniques have been aggregated artifacts are seamlessly connected to the people and objects, while receiving information to and surrounding the human environment and systematic analysis of the characteristics of human behavior began. But so far, the context-aware services are due to the limitations of hardware and communication technology had many limitations only mere physical data collected in a variety of situations hanged groups and the corresponding behavior of the human inner diversity did not understand properly. In this study the reaction pattern of the human can be inferred unique representation through factor analysis of the nature of the Hexaco, disposed in different situations Low Power Bluetooth based on the beacon and , through the type -specific nature of differentiated to provide a context-aware service. This allows the individual layers of the psychological factors that reflect a more advanced form of context-aware model presented.

프로젝션 맵핑을 이용한 마케팅 기법 연구

이원철(Woncheol Lee),김형기 한국HCI학회 2013 한국HCI학회 학술대회 Vol.2013 No.1

본 연구에서는 공간을 표현하는 매체로 사용되어지는 프로젝션 맵핑의 쓰임에 대해 현재 활발히 사용되고 있는 미디어 파사드와 빔버타이징 마케팅을 통해 예술과 상업적 마케팅의 차이점을 알아보고 표현 기법으로써 프로젝션 맵핑의 이해와 마케팅 방법으로의 빔버타이징의 새로운 가능성과 확정성을 제시하고자 한다. Used projection mapping is used as actively used in marketing, media facades aa nmd edbiiummb etoo peaxlpleretiszsin gt het hrsopuagche ttheicsh nisqtuuedsy otfo elxeparrens sitohne bdyi ffeprreonjeccet iobne twmeaepnp inga rt unadnedr stacnodminmge rcainadl mmaarrkkeettiinngg methodspalletizing of bimbeo to present new possibilities and confirmed.

점성경계 반무한 연속고가교에 대한 지진파의 영향

이상훈(Lee, Sanghun),카와나류타로(Kawana, Ryutaro),엔도타카오(Endo, Takao),이원철(Lee, Woncheol) 한국방재학회 2017 한국방재학회 학술발표대회논문집 Vol.2017 No.-

An Electrochemical Biosensor Detecting the MMP9 Using Concentric Electrode Device

JaeWoong Lee,Seongwook Choi,Jun Yeon Yun,Woncheol Lee,Dong-Sik Shin,Young June Park 대한전자공학회 2015 ITC-CSCC :International Technical Conference on Ci Vol.2015 No.6

Matrix metalloproteinase9 (MMP9) is a core protease and material of cancer migration and metastasis. Thus we suggest the electrochemical biosensor integrated with the peptide for the detection of the MMP9. In this paper, we use the substrate of MMP9, peptide labeled with Methylene blue (MB). MB is used as a redox reporter which detects the difference in the redox currents when MMP9 molecules cleave peptides. We used the pulsed bias sampling measurement and concentric electrode device. Our result shows that the ratio of current change in 50 nM concentration of MMP9 is -11.51 % and 10 nM concentration of MMP9 is -5.04 %.

지리적인 시각화를 포함하는 커뮤니티 기반의 MERS 대응 네트워크 분석

이원철 ( Woncheol Lee ),김유심 ( Yushim Kim ),오성수 ( Seong Soo Oh ),차재혁 ( Jaehyuk Cha ),김상욱 ( Sang-wook Kim ) 한국정보처리학회 2020 한국정보처리학회 학술대회논문집 Vol.27 No.2

국가적 차원에서 MERS 와 같은 재난을 잘 대처하기 위해서는 기존의 대응 네트워크를 분석할 필요가 있다. 본 논문에서는 2015 년 대한민국에서 일어난 MERS 대응 네트워크를 커뮤니티 탐지 기법을 이용하여 네트워크를 분석한다. 커뮤니티 탐지 기법은 네트워크 분석방법 중 하나로 이 기법을 통해 MERS 대응 네트워크에서 유사한 역할을 수행하는 기관들끼리 그룹핑 할 수 있다. 또한 기관들을 그룹핑 한 결과와 각 기관의 지리적인 정보를 활용하여 전국적으로 기관들이 어떻게 분포되어 있는지 살펴본다.

보안성 확보를 위한 무기체계 내장형 소프트웨어 개발 프로세스 개선 연구

이원철(Woncheol Lee),김강현(Kanghyun Kim),이승현(Seunghyeon Lee) 한국정보과학회 2016 한국정보과학회 학술발표논문집 Vol.2016 No.12

Long working hours and the risk of hypothyroidism in healthy Korean workers: a cohort study

Yesung Lee,Woncheol Lee,Hyoung-Ryoul Kim 한국역학회 2022 Epidemiology and Health Vol.44 No.-

OBJECTIVES Long working hours have been reported to cause various health problems, but are currently practiced in many countries. Building upon a previous cross-sectional study, the authors aimed to elucidate the causal relationship between long working hours and hypothyroidism through a longitudinal study. METHODS Data were collected at baseline from 45,259 participants without thyroid disease and with consistent weekly working hours (36-40, 41-52, 53-60, and >60 hours) during the follow-up period. Hypothyroidism was defined using the reference limits of serum thyroid-stimulating hormone and free thyroxine levels. By estimating hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox proportional hazards regression analysis, the risk of incident hypothyroidism was evaluated with 36-40 hours of work per week as the reference. RESULTS During 138,261.7 person-years of follow-up, 2,914 participants developed hypothyroidism (incidence density, 2.11/102 person-years). The multivariable-adjusted HRs of incident hypothyroidism for 41-52 hours, 53-60 hours, and >60 hours of work per week were 1.13 (95% CI, 1.03 to 1.24), 2.53 (95% CI, 2.17 to 2.95), and 2.57 (95% CI, 2.09 to 3.15), respectively. In dose-response analyses, long working hours had an approximately linear relationship with hypothyroidism incidence. The risk of incident hypothyroidism in those who worked 53-60 hours and >60 hours per week compared with the reference group was significantly higher among the older age group (≥36 years, stratified by median age), men, and daytime workers. CONCLUSIONS This large-scale cohort study demonstrated the association between long working hours and an increased risk of incident hypothyroidism with a dose-response relationship.