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Woo, WonKyu,Kim, Dongsik,Cho, Youngtae Korean Society for Health Education and Promotion 2012 보건교육건강증진학회지 Vol.29 No.5
Objectives: Students' life changes substantially as grade increases. It implies that risk factors that trigger students' smoking may not be consistent across grades. Most previous studies on student smoking have considered grade simply a control variable. This study examines which and to what extent risk factors are differently associated with smoking initiation according to grade level among high school students in Korea. Methods: Data from the Korean Youth Risk Behavior Web-based Survey (KYRBWS) conducted by the Korea Centers for Disease Control and Prevention (KCDC) in 2007 and 2008 were analyzed in this study. Results: Among boys, school location, school type and pocket money etc. significantly influence smoking initiation in the first grade than in any other grades, but the strength of the association decreased as grade increases except academic performance. Among girls, most independent variables were associated with smoking initiation in the second grade except school location, pocket money per week and academic performance. Conclusions: Our results suggested that the variables related smoking initiation in Korean high school students were notably different by grade and gender. These findings can serve as the basis of policy recommendations with regard to school efforts to prevent student smoking.
Identification of Keywords From Twitter and Web Blog Posts to Detect Influenza Epidemics in Korea
Woo, Hyekyung,Sung Cho, Hyeon,Shim, Eunyoung,Lee, Jong Koo,Lee, Kihwang,Song, Gilyoung,Cho, Youngtae Cambridge University Press 2018 Disaster medicine and public health preparedness Vol.12 No.3
<B>Abstract</B><B>Objective</B><P>Social media data are a highly contextual health information source. The objective of this study was to identify Korean keywords for detecting influenza epidemics from social media data.</P><B>Methods</B><P>We included data from Twitter and online blog posts to obtain a sufficient number of candidate indicators and to represent a larger proportion of the Korean population. We performed the following steps: initial keyword selection; generation of a keyword time series using a preprocessing approach; optimal feature selection; model building and validation using least absolute shrinkage and selection operator, support vector machine (SVM), and random forest regression (RFR).</P><B>Results</B><P>A total of 15 keywords optimally detected the influenza epidemic, evenly distributed across Twitter and blog data sources. Model estimates generated using our SVM model were highly correlated with recent influenza incidence data.</P><B>Conclusions</B><P>The basic principles underpinning our approach could be applied to other countries, languages, infectious diseases, and social media sources. Social media monitoring using our approach may support and extend the capacity of traditional surveillance systems for detecting emerging influenza. (<I>Disaster Med Public Health Preparedness</I>. 2018; 12: 352-359)</P>
WonKyu Woo,Dongsik Kim,Youngtae Cho 한국보건교육건강증진학회 2012 보건교육건강증진학회지 Vol.29 No.5
Objectives: Students’ life changes substantially as grade increases. It implies that risk factors that trigger students’ smoking may not be consistent across grades. Most previous studies on student smoking have considered grade simply a control variable. This study examines which and to what extent risk factors are differently associated with smoking initiation according to grade level among high school students in Korea. Methods: Data from the Korean Youth Risk Behavior Web-based Survey (KYRBWS) conducted by the Korea Centers for Disease Control and Prevention (KCDC) in 2007 and 2008 were analyzed in this study. Results: Among boys, school location, school type and pocket money etc. significantly influence smoking initiation in the first grade than in any other grades, but the strength of the association decreased as grade increases except academic performance. Among girls, most independent variables were associated with smoking initiation in the second grade except school location, pocket money per week and academic performance. Conclusions: Our results suggested that the variables related smoking initiation in Korean high school students were notably different by grade and gender. These findings can serve as the basis of policy recommendations with regard to school efforts to prevent student smoking.
Monte-Carlo 모의실험을 이용한 초·중·고등학교의환기부족 평가
최영태(Youngtae Choe),박진현(Jinhyeon Park),김은채(Eunchae Kim),류현수(Hyoensu Ryu) 김동준(Dong Jun Kim),민기홍(Kihong Min),정다영(Dayoung Jung),우병렬(Byung Lyul Woo),조만수(Mansu Cho),양원호(Wonho Yang) 한국환경보건학회 2020 한국환경보건학회지 Vol.46 No.6
Objectives: Indoor air quality has become more important aspeople spend most of their times indoors. Since students spend most of their times at home or at school, they are more likely to be exposed to indoor air pollutants. Ventilation in school classrooms can affect health and learning performance. In this study, ventilation deficiency was evaluated in school classrooms using Monte Carlo simulation. Methods: This study used sensor-based monitoring for six months to measure carbon dioxide (CO2) concentrations in classrooms in elementary, middle, and high schools. The volume of the classroom and the number of students were investigated, and the students’ body surface area was used to calculate the CO2 emission rate. The distribution of ventilation rates was estimated by measured CO2 concentration and a massbalance model using Monte Carlo simulation. Results: In the elementary, middle, and high schools, the average CO2 concentrations exceeded 1000 ppm, indicating that the ventilation rates were insufficient. The ventilation rates were deficient from July to August and in December, but showed relatively high ventilation rates in October. Forty-three percent of elementary schools, 56% of middle schools, and 62% of high schools showed insufficient ventilation rates. Conclusions: The ventilation rates calculated in elementary, middle and high schools were found to be quite insufficient. Therefore, proper management is needed to overcome the lack of ventilation and improve air quality.
농업용 드론의 비행속도 및 고도에 따른 하향풍 특성 분석
윤영태 ( Youngtae Yun ),유승화 ( Seunghwa Yu ),우제근 ( Jeakeun Woo ),김영화 ( Younghwa Kim ),최덕규 ( Duckkyu Choi ),최일수 ( Ilsu Choi ),최용 ( Yong Choi ) 한국농업기계학회 2020 한국농업기계학회 학술발표논문집 Vol.25 No.2
회전익(rotary wing) 무인비행체로 분류되는 드론(Drone)은 최근 사용의 용이성, 우수한 기동성, 정확한 모니터링 능력으로 농업에서의 활용도가 높아 드론을 이용한 파종, 방제, 농작물 병해충 및 작황 예찰용 등으로 이용되고 있다. 농업에서 이용되는 대다수의 드론은 방제용으로 드론의 비행속도와 고도에 따라 방제 성능 차이가 발생한다. 때문에 드론의 비행각도와 로터 회전수에 따른 비행속도와 로터 블레이드 모터와 지면까지의 높이에 따른 하향풍속을 분석해볼 필요가 있다고 판단되었다. 이에 본 연구에서는 농업용 방제 드론의 비행속도 및 고도에 따른 하향풍속을 분석하여 최적의 비행조건을 찾고자 하였다. 외부 조건에 영향을 받지 않고 드론의 하향풍속만을 측정하기 위해서는 외부환경의 영향을 받지 않는 실내 공간이 필요하였다. 이에 농업기술실용화재단에서 구축한 농업용무인항공살포기 실내검정시스템을 이용하였으며, 21 in 로터 블레이드가 8개인 8엽기를 선정하였다. 실험 요인은 드론의 비행속도 1m/s, 2m/s, 3m/s(기체의 Pitch값과 로터 rpm값 조정) 3수준과 고도 1.0H, 2.0H, 3.0H(로터 모터와 열선 풍속 프로브 간의 수직 거리 조정) 3수준 2가지로 설정하고, 열선 풍속 프로브가 풍속을 처음으로 감지하는 위치를 시작점으로 0.2m씩 이동하며 실험을 수행하였다. 그 결과, 하항풍속 데이터 값은 드론의 비행속도에 관계없이 유사한 값이 측정되었으며 위치별 하향풍의 형태 또한 비슷한 경향을 보였다. 하지만, 고도에 따른 차이는 존재하였다. 고도 1.0H와 2.0H에서 최대풍속 약 11.0m/s의 유사한 풍속이 측정되었지만, 고도 1.0H 일 때 열선 풍속 프로브와의 거리 0.6m에서 약 4m/s까지 풍속이 줄어들었다가 다시 약 9m/s까지 풍속이 증가한 후 1.2m에서 풍속이 감소하는 것으로 나타났다. 이는 드론 중앙부와 열선 풍속 프로브 사이의 거리가 짧아 로터 블레이드 회전에 의한 풍속이 해당 위치에서 약해지는 지점이 생기는 것으로 분석되었다. 고도 3.0H일 때 최대풍속 약 6.0m/s로 다소 약한 풍속이 측정되어 방제작업 시 로터 블레이드 회전력에 의한 하향풍의 세기가 상대적으로 약할 것으로 예측되었다. 이에 농업용 드론의 방제작업 시 비행속도 3m/s, 비행고도 2.0H 일 때 가장 빠르고 균일한 방제가 가능할 것으로 판단되었으며, 향후 4m/s 이상의 비행속도에서의 추가 실험을 통해 비행속도에 의한 하향풍속의 영향을 비교 분석할 필요가 있다고 판단되었다.