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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>
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.
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.
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.
Rational Biosynthetic Engineering for Optimization of Geldanamycin Analogues
Kim, Woncheol,Lee, Dongho,Hong, Seong Su,Na, Zhu,Shin, Jin Chul,Roh, Su Heun,Wu, Cheng-Zhu,Choi, Oksik,Lee, Kyeong,Shen, Yue-Mao,Paik, Sang-Gi,Lee, Jung Joon,Hong, Young-Soo WILEY-VCH Verlag 2009 Chembiochem Vol.10 No.7
<P>Tailor made: We report the rational biosynthesis of C15 hydroxylated non-quinone geldanamycin analogues by site-directed mutagenesis of the geldanamycin polyketide synthase (PKS), together with a combination of post-PKS tailoring genes. Rational biosynthetic engineering allowed the generation of geldanamycin derivatives, such as DHQ3 illustrated in the figure, which had superior pharmacological properties in comparison to the parent compound. <img src='wiley_img/14394227-2009-10-7-CBIC200800763-content.gif' alt='wiley_img/14394227-2009-10-7-CBIC200800763-content'> </P><P>A rational biosynthetic engineering approach was applied to the optimization of the pharmacological properties of the benzoquinone ansamycin, geldanamycin. Geldanamycin and its natural or semisynthetic derivatives have the potential to serve as anticancer chemotherapeutic agents. However, these first-generation Hsp90 inhibitors share an unfavorable structural feature that causes both reduced efficacy and toxicity during clinical evaluation. We report the rationally designed biosynthesis of C15 hydroxylated non-quinone geldanamycin analogues by site-directed mutagenesis of the geldanamycin polyketide synthase (PKS), together with a combination of post-PKS tailoring genes. A 15-hydroxyl-17-demethoxy non-quinone analogue, DHQ3, exhibited stronger inhibition of Hsp90 ATPase activity (4.6-fold) than geldanamycin. Taken together, the results of the present study indicate that rational biosynthetic engineering allows the generation of derivatives of geldanamycin with superior pharmacological properties.</P> <B>Graphic Abstract</B> <P>Tailor made: We report the rational biosynthesis of C15 hydroxylated non-quinone geldanamycin analogues by site-directed mutagenesis of the geldanamycin polyketide synthase (PKS), together with a combination of post-PKS tailoring genes. Rational biosynthetic engineering allowed the generation of geldanamycin derivatives, such as DHQ3 illustrated in the figure, which had superior pharmacological properties in comparison to the parent compound. <img src='wiley_img/14394227-2009-10-7-CBIC200800763-content.gif' alt='wiley_img/14394227-2009-10-7-CBIC200800763-content'> </P>
Choy, Woncheol,Lee, Sanghyo,Lee, Yoonsun,Kim, Jaejun Architectural Institute of Japan 2010 JOURNAL OF ASIAN ARCHITECTURE AND BUILDING ENGINEE Vol.9 No.1
<P>The objective of this study is to analyze the influence of landmark factors on the price of super high-rise residential buildings. The level of influence is analyzed by means of an hedonic pricing model. In this paper the height and area are identified as landmark factors in analyzing the landmark's influence quantitatively. Also, the concept of relative quantity is introduced regarding the height and area because the landmark factors involve comparisons with neighboring buildings rather than by the building's absolute characteristics alone. Relative height and relative area derived by such an approach were established as independent variables for the hedonic pricing model, along with conventional price-determining factors. Samples subjected to this analysis included thirty super high-rise residential buildings each containing at least thirty stories and all located in Seoul. Results from a linear regression model and a semi-log regression model revealed that p-values were less than 0.05, indicating that the regression coefficients of relative height and relative number of stories are significant.</P>