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김시온 ( Kim Sion ),조은하 ( Jo Eunha ),최수훈 ( Choi Soohoon ) 한국물환경학회 2020 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2020 No.-
In the current research, various conditions were evaluated to understand the release of fibrous microplastics and organic leachate from teabags. Six commercial teabags composed of 4 different plastic materials were tested under different temperatures, fiber damages, and water contact times. The main object of the research was to verify the amount of microplastics or organic leachate that may occur in tea consumed in our every day lives. The main focus was to verify the fibrous microplastic release and organic leachate of teabags under different damages. Damages of 1 ~ 10 cm were conducted on the teabags and submerged in glass vials under different temperatures. The teabags were cut with steal scissors of different degrees and the tea leaves were removed. Empty teabags were washed with deionized (DI) water for three trials before the experiments were conducted. Three empty teabags were submerged in every glass vial and submerged under constant temperatures in a water bath. the water bath contained a shaker where the samples were shaked during each trial. After being submerged in the water bath, the water from the teabags were filtered through a cellulous acetate membrane filter with pore sizes of 1 μm. Each filter was rinsed thoroughly and filtered with DI water before filtrations of the teabag samples. Filtered fibrous microplastics were counted with an optical microscope. Residual microplastics in the filtered water were analyzed with a TOC anayzer, dynamic light scattering analyzer, and SEM imaging. Results showed a logametric increase for both fibrous microplastic release and organic leachate with the increase of the damage inflicted on the teabags. Samples under higher temperatures also showed a higher release of the fibrous microplastics and leached TOC matter. The time for which the damaged teabags were submerged under water also showed a strong correlation with plastic release and TOC leaching. The hydraulic size of the filtered microplastics were in the size range of 1 nm to 2.4 μm. SEM resulted also showed similar sizes of microplastics with EDX results indicating the fibers as polymeric matters. The type of teabags and its assembly method also indicated a degree of influence in the release and leachate of the teabags. The current research has showed the amount of potential mircroplastic consumption via tea consumption.
스파크 클러스터 환경에서의 대규모 로그 이상 패턴 분석
민시온(Sion Min),김유양(Youyang Kim),탁병철(Byungchul Tak) 한국컴퓨터정보학회 2024 韓國컴퓨터情報學會論文誌 Vol.29 No.3
This study explores the correlation between system anomalies and large-scale logs within the Spark cluster environment. While research on anomaly detection using logs is growing, there remains a limitation in adequately leveraging logs from various components of the cluster and considering the relationship between anomalies and the system. Therefore, this paper analyzes the distribution of normal and abnormal logs and explores the potential for anomaly detection based on the occurrence of log templates. By employing Hadoop and Spark, normal and abnormal log data are generated, and through t-SNE and K-means clustering, templates of abnormal logs in anomalous situations are identified to comprehend anomalies. Ultimately, unique log templates occurring only during abnormal situations are identified, thereby presenting the potential for anomaly detection.
김예술,박시온,박건웅,Kim, Yesool,Park, Sion,Park, Gunwoong 한국통계학회 2020 응용통계연구 Vol.33 No.6
Seoul public bike program facilitates access to bicycles and offers potential for greater mobility and health for users. Furthermore, it would have positive impacts on transport congestion, energy use, and the environment. Hence, it is important to find future rental locations by taking to account both bike-demand and regional imbalance. This paper first finds eligible candidates of rental locations with the required spatial conditions such as a sufficient sidewalk width and accessibility of bike pick-up vehicles. And then, estimates public bike daily usage for each selected location via random forest based on Seoul public bike historical usage, Seoul geographical features, regional characteristics, and populations. This study contributes to a better comprehension of the Seoul public bike program, and would be useful in determining new public bike rental locations. 서울시는 시민의 건강 증진과 이산화탄소 저감을 통한 저탄소 녹색성장 실현을 목표로 2015년부터 2020년 현재까지 공공자전거 대여소를 확장하고 있다. 매년 공공자전거에 대한 시민들의 접근성과 이용률이 증가하고 있으며, 이에 서울시는 수요와 접근성을 모두 고려한 공공자전거 대여소 신규 입지를 확장하고자 노력하고 있다. 공공자전거 대여소 위치는 주변 지형지물에 영향을 받으며, 수요량은 지역적 특성에 영향을 받으므로 이들을 고려한 신규 대여소 입지를 선정해야 할 필요성이 있다. 따라서 본 연구는 서울시 공공자전거의 새로운 입지 선정을 위하여 2019년 서울시 공공자전거 데이터와 지리정보체계, 대중교통, 인구 등의 데이터를 전처리하여 신규 대여소 거치가 가능한 장소를 선별하고, 랜덤 포레스트를 이용하여 신규 대여소의 이용량을 예측하였다. 이를 바탕으로 평균 경사도, 대중교통과의 거리, 특화 시설과의 거리, 하천과의 거리 등이 자전거 이용량에 영향을 미치는 주요한 요소임을 도출할 수 있었다. 본 결과는 신규 대여소 설치 지역을 결정하는데 객관적인 통계적 지표가 될 것으로 기대한다.