• 우주기술과 응용
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• 제3권4호
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• pp.301-321
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• 2023

The Journal of Astronomy and Space Sciences (JASS) has published research papers on a range of topics since its initial publication in 1984, giving space science researchers a platform. In this paper, we reviewed recent publications (2019-2023) that deal with the space environment. In the space environment field, we reviewed 37 papers published in JASS during this time, covering research topics such as the sun, magnetosphere, ionosphere, atmosphere, and space radiation. We hope that researchers in the field will make use of this in the future as it will allow us to share the most recent trends in the field of space environment research that is currently underway.

• 한국환경과학회지
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• 제23권9호
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• pp.1609-1618
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• 2014

In this study, as a fundamental study for the remediation of the radionuclides-contaminated soil, the adsorption of cobalt, strontium, and cesium on natural soil and kaolin were experimently investigated and adsorption characteristics were evaluated by using several adsorption kinetic and isotherm models. The pseudo-first-order kinetic model (PFOM), pseudo-second-order kinetic model (PSOM), one-site mass transfer model (OSMTM), and two compartment first-order kinetic model (TCFOKM) were used to evaluate the kinetic data and the pseudo-second-order kinetic model was the best with good correlation. The adsorption equilibria of cobalt, strontium, and cesium on natural soil were fitted successfully by Redlich-Peterson and Sips models. For kaolin, the adsorption equilibria of cobalt, strontium, and cesium were fitted well by Redlich-Peterson, Freundlich, and Sips models, respectively. The amount of adsorbed radionuclides on natural soil and kaolin was in the order of cesium > strontium > cobalt. It is considered that these results could be useful to predicting the adsorption behaviors of radionuclides such as cobalt, strontium, and cesium in soil environments.

• 정보처리학회논문지B
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• 제10B권7호
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• pp.785-794
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• 2003

지금까지 가상 환경을 무대로 하는 게임 등에서 자연 현상의 처리는 시각적인 사실성에 치우친 그래픽 처리 위주로 연구되어져 왔다. 그러나 인과관계(causality)를 고려하지 않은 자연 현상들의 발생과 법칙에 기반하지 않은 현상들의 전개는 논리적 사실성을 감소시켜 사용자들의 몰입감을 떨어뜨린다. 본 논문에서는 자연 현상 중에서 태양복사(solar radiation)와 바람에 초점을 맞추어서, 이들의 다양하고 예측하기 어려운 발생과 전개과정을 시뮬레이션 하는 것을 목적으로 한다. 이를 위해 ontology에 기반한 객체들의 구조를 살펴보고, 이들을 바탕으로 가상 환경을 구성하였을 때 가상 환경의 데이타를 관리하는 방안을 제시한다. 그리고 각 자연 현상 이벤트에 대한 과정을 단계별로 상세히 다루고, 나아가 객체가 정성적 변화를 하였을 때 상황을 처리하는 방법을 제시한다.

• 천문학회보
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• 제43권1호
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• pp.32.1-32.1
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• 2018

Searching for low surface brightness (LSB) dwarf galaxies in low density environments (isolated and group) can help us resolve the discrepancy between observation and theory known as the 'missing satellite' problem. They are also important to study the evolution of low mass galaxies in these environments. Although the number of dwarfs in such environments is rapidly increasing in many recent studies, it is still not easy to characterize their general properties. Motivated by this, we present preliminary results of our search for LSB dwarf galaxies around 60 nearby galaxies (D<50Mpc) using deep optical images. Imaging data from Maidanak Astronomical Observatory (MAO) in Uzbekistan as a part of Intensive Monitoring Survey of Nearby Galaxies (IMSNG; Im in prep.) and other archival data are used to find previously unknown LSB dwarf galaxies. Extended LSB sources (central surface brightness ${\mu}_0$ > $23mag/arcsec^2$) are first selected in the ${\mu}_0$ - magnitude plane (Rines & Geller 2008). The dwarf galaxy candidates are chosen by visual inspection. We discuss whether these candidates are actual satellite galaxies, by measuring the projected number densities in group environments and in the field. Also, their structural and photometric properties are compared with those of previously discovered dwarf galaxies in the literature.

• 한국물환경학회지
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• 제28권4호
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• pp.531-537
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• 2012

The information about the physicochemical environments, the species distribution and community of the epilithic diatom cells in Pyengchang river and inflow streams of Gangwon-do were studied for assessment of biological water quality from June 2008 to October 2010. Total 112 diatom taxa were identified with 2 orders, 9 families, 26 genera, 95 species and 17 varieties. Among the total taxa identified, 13 taxa, 52 taxa and 15 taxa represented the family Achnanthaceae, Naviculaceae and Bacillariaceae, respectively. The pH values of the water was found to be neutral to alkaline due to the limestone grounds of Pyengchang river and inflow streams. The 13 taxa including Epithemia adnata, belonged to alkaline-water diatoms, and three species - Cymbella japonica, Eunotia major and Fragilaria capitellata - are known to be acidic-water species. The species, Hannaea arcus, known as a cryophilic and mountain periphyton was identified at IF2, IF3 and IF4 in low water temperature environments at high altitudes, being a dominating species in P1 and IF1. Four saproxenous species - Achnanthes convergens, Cocconeis placentula var. lineata, Cymbella turgidula and Hannaea arcus - were dominant at some sampling sites. For biological water quality assessment, IF2, IF3 and P3 showed low water quality class. The values of DAIpo and TDI were 10.6 ~ 98.0 and 13.8 ~ 94.2, respectively. Therefore, biological water quality in Pyengchang river and inflow streams was relatively desirable.

• 한국양식학회지
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• 제12권2호
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• pp.101-105
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• 1999

Predater, tarpon (Megalops atlanticus) has a specific preferring preys in natural environments. To investigate this, young tarpon were captured and their stomach contents were weighed and sorted based on taxonomic groups. Average standard length and body weight for tarpon captured were 11.49 cm and 34.67 g, respectively. The average weight of the stomach contents in the tarpon was 0.83 g. The status of digestion extent of the consumed preys was 2.37 which indicated that preys were relatively well digested. The main preys in tarpon stomach were other fishes (mosquito fish and sheepshead minnow) and shrimp. Frequency occurrence of fishes in tarpon stomach was highest (P＜0.05). Also, frequency occurrence of shrimp was higher than that of fly (P＜0.05). Mean individual number of fish found in tarpon stomach was 2.66 per tarpon and it was higher than that of shrimp or fly (P<0.05). There was linear regression between the total weight of the consumed preys and the standard length of tarpon; Y (Total weight of preys) = 0.3151 $\times$ (Standard length of tarpon) - 2.7123, $R^2$=0.6140. Also, there was the strong linear regression between the total weight of the consumed preys and weight of the tarpon; Y (Total weight of preys) = 0.0299 $\times$ (Body weight of tarpon) - 0.0774, $R^2$=0.7882. These results indicated that the main preys for young tarpon in their natural environments were small fish composed of mosquito fish and sheepshead minnow and shrimp. And there was the stronger correlation between the total weight of preys and the body weight of tarpon than that between the total weight of preys and the standard length of tarpon.

• 지질공학
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• 제10권2호
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• pp.215-233
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• 2000

전국의 자연환경에서의 지구화학적 재해를 정량적으로 평가할 수 있는 체계를 구축하기 위하여, 지난 4년간 경기-수도권, 충남, 충북, 전남, 전북 등 국토 서반부 전역(45,000km$^2$)에 분포하는 1-2차 수계(총 11,000 개)의 하천퇴적물(150 $\mu$m 이하의 표사)을 대상으로 주원소 성분 10종과 미량원소 26종에 대해 지화학도를 작성하였다. 각 지질(구성암석)별 자연 배경치, 권역별 방대한 시료의 분석자료의 통계처리에 근거한 평균치 등 다양한 기준치를 설정하고, 유해원소의 과다농집과 필수성분의 결핍현상 등 지구화학적 재해의 유형별 평가에 필요한 등급을 설정.제시하였다. 실제로 몇 가지 지구화학적 재해사례를 권역별로 선별하여 다양한 전산 지화학도와 평가기준치에 근거하여 고찰하였다.

• 한국물환경학회지
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• 제38권1호
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• pp.31-42
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• 2022

Dissolved organic matter (DOM), which changes according to various factors, is ubiquitously present from natural environments to engineered treatment systems. Only limited information is available regarding the environmental functions of DOM after bulk analyses are only applied for characterization. In this paper, latest DOM analytical techniques are briefly introduced, which include fluorescence excitation-emission matrix with parallel factor analysis (EEM-PARAFAC), size-exclusion chromatography with an organic carbon detector (SEC-OCD), carbon/nitrogen stable-isotope ratio, and Fourier transform-ion cyclotron resonance-mass spectroscopy (FT-ICR-MS). Recent examples of using advanced analyses to interpret the phenomena associated with DOM occurring in natural and engineered systems are presented here. Through EEM-PARAFAC, different components like protein-like, fulvic-like, and humic-like can be identified and tracked individually through the investigated systems. SEC-OCD allows researchers to quantify different size fractions. FT-ICR-MS provides thousands of molecular formulas present in bulk DOM samples. Lastly, carbon/nitrogen stable-isotope ratio offers reasonable tools for tracking the sources in environments. We also discuss the advantages and weakness of the above-mentioned characterizing tools. Specifically, they focus on single environmental factors (different sourced-DOM and interaction of sediment-pore water) or simple changes after individual treatment processes. Through collaboration with the advanced techniques later, they help the researchers to better understand environmental behaviors in aquatic systems and serve as essential tools for addressing various pending problems associated with DOM.

• 한국학교보건학회지
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• 제6권2호
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• pp.24-55
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• 1993

School health aims to guide and manage growing students from elementary schools to high schools in order to grow healthily through the formation of healthy life habits, the self-control health management guide and the making of pleasant school health environments. Even though this school health plays an important role in guiding the students who are in the period of growing to have a perfect personality as a democratic people of our country in the school education, there are many lacks, such as they still don't know the word itself, "school health" or recognize its importance. Also it's a real condition to practice items concerned with the health under the condition of unestablished structure. 1. The results of analyzing school health real conditions. Based on treatises concerned with school health and various statistical materials which are announced by concerned people. We divided and analyzed school health into the items concerned with health education, the items with health management, and the items with school health environments, and investigated the level of the present school health and its necessity. As the items concerned with health education, we investigated the necessary range of school health education, the effect of health education on children's daily life, family's health and the interesting contents of school health. And as the items with health management, I investigated children's obesity, dental caries, eyesight, clinics, a health examination, drug abuse, spirit health, providing meals for school children, and school health manpower. And as the items conerned with school health environments, we investigated the recognition of the problem of natural environments, the management of purification district around the school, the problem of environments within the school and classroom lighting. As the results of analyzing these, I realized that the present level of school health is still in unsatisfactory situation and school health is needed necessary. 2. The establishment of school health. In order to set the school health, above all, the management system of School health should be set. I classified and systemized the contents of each item which had been promoted till now according to the function. They are classified as followings Based on classifying school health into (1) health education, (2) health management and (3) health environments, I divided school health education into the health education of health subjects, the health education of concerned subjects and the education of health life. And I divided health management into the health managements for a prevention and a cure. And I divided health environments into the environment around the school and within the school. Each system set like these is not fixed invariably and I should keep the relationship of mutual supplement between health education and health management, between health management and health environments, and between health environments management and health education. When we run these systemetic school health, students' health could be maintained and improved to more proper directions.

• Structural Engineering and Mechanics
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• 제63권4호
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• pp.471-480
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• 2017

This paper investigates free vibration characteristics of a rotating functionally graded (FG) beam in hygro environments. In the present study, material properties of the FG beam vary continuously through thickness direction according to the power-law which approximates material properties of FG beam. The governing differential equations of motion are derived based on Euler-Bernoulli beam theory and using the Hamilton's principle which solved utilizing a semi-analytical technique called the Differential Transform Method (DTM). In order to verify the competency and accuracy of the current analysis, a comparative study with previous researches are performed and good agreement is observed. Influences of Several important parameters such as power-law exponent, hygro environment, rotational speed and slenderness ratio on natural frequencies are investigated and discussed in detail. It is concluded that these effects play significant role on dynamic behavior of rotating FG beam in the hygro environments. Numerical results are tabulated in several tables and figures that can be serving as benchmarks for future analyses of rotating FG beams in the hygro environments.