• Title/Summary/Keyword: SSA

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Estimation of Ground-level PM10 and PM2.5 Concentrations Using Boosting-based Machine Learning from Satellite and Numerical Weather Prediction Data (부스팅 기반 기계학습기법을 이용한 지상 미세먼지 농도 산출)

  • Park, Seohui;Kim, Miae;Im, Jungho
    • Korean Journal of Remote Sensing
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    • v.37 no.2
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    • pp.321-335
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    • 2021
  • Particulate matter (PM10 and PM2.5 with a diameter less than 10 and 2.5 ㎛, respectively) can be absorbed by the human body and adversely affect human health. Although most of the PM monitoring are based on ground-based observations, they are limited to point-based measurement sites, which leads to uncertainty in PM estimation for regions without observation sites. It is possible to overcome their spatial limitation by using satellite data. In this study, we developed machine learning-based retrieval algorithm for ground-level PM10 and PM2.5 concentrations using aerosol parameters from Geostationary Ocean Color Imager (GOCI) satellite and various meteorological parameters from a numerical weather prediction model during January to December of 2019. Gradient Boosted Regression Trees (GBRT) and Light Gradient Boosting Machine (LightGBM) were used to estimate PM concentrations. The model performances were examined for two types of feature sets-all input parameters (Feature set 1) and a subset of input parameters without meteorological and land-cover parameters (Feature set 2). Both models showed higher accuracy (about 10 % higher in R2) by using the Feature set 1 than the Feature set 2. The GBRT model using Feature set 1 was chosen as the final model for further analysis(PM10: R2 = 0.82, nRMSE = 34.9 %, PM2.5: R2 = 0.75, nRMSE = 35.6 %). The spatial distribution of the seasonal and annual-averaged PM concentrations was similar with in-situ observations, except for the northeastern part of China with bright surface reflectance. Their spatial distribution and seasonal changes were well matched with in-situ measurements.

A study on Sesi Keesokshi in the late Joseon Period -Focusiong on Serial Sesi Keesokshi- (조선후기 세시기속시(歲時記俗詩) 고찰 -대보름 연작형(聯作型) 세시기속시를 중심으로-)

  • Yang, Jin-jo
    • Korean Journal of Heritage: History & Science
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    • v.40
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    • pp.307-323
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    • 2007
  • One of the distinguishing features of late Jeosun s Hanshi (poem in Chinese) is the numerous creation of Yeonjachyung Keesokshi (serial poem on folklore) which describes the folk manner and folk way of life in detail. Keesokshi s subject matter is the folklike in general including local features, geography, climate, local production, humanity, social conducts, and daily labor for living as well. By its material characteristics, Keesokshi reflects detailed life conditions of the society members in each levels, and represents the local customs as well as the folk emotions. Among the several kinds of Keesokshis, a Sesi Keesokshi focuses only in reciting the folk customs on each seasonal festival days, and the great numbers of such serial poems appear during the latter part of the Jeosun Dynasty. Its overall background is the transition of artistic trend which came after many social changes such as expansion of realism, uprising national consciousness, shaken status system, and the rising of 'Jeosun si motives in the Hansi history. Moreover, each writers various experiences and their interests in the reality and critical minds of common people contributed a crucial roll in creation of Sesi Keesokshi. 178 of the 584 remaining serial Sesi Keesokshi are written particularly about the folk customs in The Grand Full Moon Festival (the first full moon of a year by the lunar calendar). These Hanshis widely reflect the common ways of living by directly accepting the seasonal folk customs as the subject matters. Especially, close to the reality, these poems positively express the people's simple vigorous lives and create unrestrained lively image by describing the joys and sorrows of the folk ewistence along with their craving. Also, it is notable to have customs such as 'Shil-Ssa-Um' and 'No-gu-ban-kong-yang' as subjects for its rarity in other literatures.

A study on the detailed treatment techniques of seoktap(stone stupa) in Jeollado province -in the groove for dropping water and the hole for wing bell of the okgaeseok(roof stone)- (전라도 석탑의 세부 기법 고찰 - 옥개석 물끊기홈과 충탁공을 중심으로 -)

  • Cho, Eun-kyung;Han, Joo-sung;Nam, Chang-keun
    • Korean Journal of Heritage: History & Science
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    • v.40
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    • pp.271-306
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    • 2007
  • One of the distinguishing features of late Jeosun's Hanshi (poem in Chinese) is the numerous creation of Yeonjachyung Keesokshi (serial poem on folklore) which describes the folk manner and folk way of life in detail. Keesokshi's subject matter is the folklike in general including local features, geography, climate, local production, humanity, social conducts, and daily labor for living as well. By its material characteristics, Keesokshi reflects detailed life conditions of the society members in each levels, and represents the local customs as well as the folk emotions. Among the several kinds of Keesokshis, a Sesi Keesokshi focuses only in reciting the folk customs on each seasonal festival days, and the great numbers of such serial poems appear during the latter part of the Jeosun Dynasty. Its overall background is the transition of artistic trend which came after many social changes such as expansion of realism, uprising national consciousness, shaken status system, and the rising of 'Jeosunsi' motives in the Hansi history. Moreover, each writer's various experiences and their interests in the reality and critical minds of common people contributed a crucial roll in creation of Sesi Keesokshi. 178 of the 584 remaining serial Sesi Keesokshi are written particularly about the folk customs in The Grand Full Moon Festival (the first full moon of a year by the lunar calendar). These Hanshis widely reflect the common ways of living by directly accepting the seasonal folk customs as the subject matters. Especially, close to the reality, these poems positively express the people's simple vigorous lives and create unrestrained lively image by describing the joys and sorrows of the folk existence along with their craving. Also, it is notable to have customs such as 'Shil-Ssa-Um' and 'No-gu-ban-kong-yang' as subjects for its rarity in other literatures.