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열화상 이미지와 환경변수를 이용한 콘크리트 균열 깊이 예측 머신 러닝 분석
김지형,장아름,박민재,주영규,Kim, Jihyung,Jang, Arum,Park, Min Jae,Ju, Young K. 한국공간구조학회 2021 한국공간구조학회지 Vol.21 No.2
This study presents the estimation of crack depth by analyzing temperatures extracted from thermal images and environmental parameters such as air temperature, air humidity, illumination. The statistics of all acquired features and the correlation coefficient among thermal images and environmental parameters are presented. The concrete crack depths were predicted by four different machine learning models: Multi-Layer Perceptron (MLP), Random Forest (RF), Gradient Boosting (GB), and AdaBoost (AB). The machine learning algorithms are validated by the coefficient of determination, accuracy, and Mean Absolute Percentage Error (MAPE). The AB model had a great performance among the four models due to the non-linearity of features and weak learner aggregation with weights on misclassified data. The maximum depth 11 of the base estimator in the AB model is efficient with high performance with 97.6% of accuracy and 0.07% of MAPE. Feature importances, permutation importance, and partial dependence are analyzed in the AB model. The results show that the marginal effect of air humidity, crack depth, and crack temperature in order is higher than that of the others.
텍스트 마이닝을 활용한 성별에 따른 타투에 대한 인식 차이 분석 - 유튜브 영상의 제목과 댓글 중심으로 -
장정윤(Chang, Jung-yoon),장민재(Jang, Min-jae) 숙명여자대학교 아시아여성연구원 2024 아시아여성연구 Vol.63 No.1
이 연구는 남성과 여성이 타투에 대한 인식과 타투를 한 사람들에 대한 평가가 성별에 따라 어떻게 다른지를 탐색하고자 시작되었다. 타투에 대한 사회적 인식의 변화를 배경으로, 유튜브 영상의 제목과 댓글을 텍스트 마이닝의 키워드 빈도 분석을 통해 분석함으로써, 타투에 대한 성별 의식을 객관적으로 살펴보았다. 이 과정에서, 남성과 여성 모두 타투를 ‘하는’ 것에 대한 주체적인 의지를 강조하며, 각자가 중요하게 여기는 내면적인 의미와 깊게 연결되어 있음을 발견했다. 남성은 타투를 통해 외형적 자신감과 타인과의 관계를 강조하는 경향이 있다면, 여성은 자신의 성취를 드러내는 것에 더 큰 가치를 두는 경향이 있다. 특히, 여성이 자신의 행동을 기록하는 것을 중요하게 여기는 경향이 강한 것을 ‘브이로그’의 빈도수를 통해 확인하였다. 그리고 텍스트 마이닝의 감정 분석을 활용한 이 연구는 유튜브 영상에 대한 일반인들의 댓글 연구를 통해 남녀 간의 경향 차이를 넘어, 타투에 대한 남녀의 감정을 구체적으로 확인할 수 있었다. 사회적 인식이 변화하지만, 여성의 타투에 대한 부정적인 감정이 여전히 높게 나타났음을 확인할 수 있었다. 이러한 결과는 타투에 대한 성별에 따른 인식과 태도의 차이를 명확하게 보여주며, 타투에 대한 사회적 인식의 변화를 더 깊게 이해할 수 있는 기반을 제공한다. This study delves into the nuanced perspectives of men and women regarding tattoos, exploring how their evaluations of individuals with tattoos differ based on gender. Against the backdrop of evolving social perceptions toward tattoos, this study offers an objective analysis of gender consciousness regarding tattoos through a keyword frequency analysis of YouTube video titles and comments by employing text mining. Throughout the investigation, both men and women emphasized their autonomy in choosing tattoos, revealing a deep connection to personal meanings. Men tended to emphasize outward confidence and interpersonal relationships through their tattoos, whereas women placed greater emphasis on showcasing personal achievements. In particular, women exhibited a propensity for recording their actions, as evidenced by the high prevalence of “vlogs.” Text mining analyses unveiled distinct disparities between men and women regarding the motivations and utilization of tattoos. Furthermore, an emotion analysis of YouTube comments revealed the specific sentiments expressed by men and women toward tattoos, going beyond mere trend differentials. Despite the evolving social perceptions, a significantly higher prevalence of negative emotions toward tattoos was observed among women. These findings clearly elucidate the differences in perceptions and attitudes toward tattoos based on gender, laying the foundation for a deeper understanding of shifting social perceptions regarding tattoos.
다단 임팩터 Nanosampler를 이용한 진주시 대기에어로졸입자의 입경별 질량농도 특성
박정호 ( Jeong Ho Park ),장민재 ( Min Jae Jang ),김형갑 ( Hyoung Kab Kim ) 한국환경과학회 2015 한국환경과학회지 Vol.24 No.5
Atmospheric aerosol particles were investigated at GNTECH university in Jinju city. Samples were collected using the Nanosampler period from January to December 2014. The Nanosampler is a 6 stage cascade impactor(1 stage : > 10 μm, 2 stage : 2.5~10 μm, 3 stage : 1.0~2.5 μm, 4 stage : 0.5~1.0 μm, 5 stage : 0.1~0.5 μm, back-up : < 0.1 μm) with the stages having 50% cut-off ranging from 0.1 to 10 μm in aerodynamic diameter. The mass size distribution of Atmospheric aerosol particles was unimodal with peak at 1.0~2.5 μm or 0.5~1.0 μm. The annual average concentrations of TSP, PM10, PM2.5, PM1, PM0.5 and PM0.1 were 44.0 μg/m3, 40.3 μg/m3, 31.4 μg/m3, 18.0 μ g/m3, 8.2 μg/m3, 3.0 μg/m3, respectively. On average PM10, PM2.5, PM1, PM0.5 and PM0.1 make up 0.91, 0.70, 0.41, 0.19 and 0.07 of TSP, respectively. The annual average of PM2.5/PM10 ratio was 0.77.
박정호 ( Jeong Ho Park ),장민재 ( Min Jae Jang ),김형갑 ( Hyoung Kab Kim ) 한국산업보건학회 2016 한국산업보건학회지 Vol.26 No.1
Objectives: This study was performed to measure and evaluate the concentration, size distribution and fugitive emission of particulate matter from process operations at foundries. Methods: Particle matter was collected from three foundries, and samples were also collected from a background site for calculating the fugitive emission concentration of the foundries. For the collection of the samples, a Nanosampler cascade impactor was used. Results: The concentration of TSP in the samples collected from the three foundries was 0.675~1.222 mg/m(3), PM10 was 0.525~1.018 mg/m3 and PM(2.5) was 0.192~0.615 mg/m(3). The mass size distribution was bimodal or monomodal with maximum peak at two stage(size 2.5~10 μm). The mass median aerodynamic diameter(MMAD) was 1.80~3.98 μm. The fugitive emission concentration of TSP varies in the range of 0.65 to 1.21 mg/m(3), which exceeds the emission standard of fugitive dust(0.5 mg/m(3)). Conclusions: Particle concentration and size is an important industrial hygiene factor to protect foundry workers. Furthermore, the presence of high emission of particulate pollutants has a significant negative impact on the ambient air of the study area. Therefore, it is important to improve both the process and prevention facility in oder to reduce particulate pollutants in foundries.