• Title/Summary/Keyword: 환경권

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Retrieval of Hourly Aerosol Optical Depth Using Top-of-Atmosphere Reflectance from GOCI-II and Machine Learning over South Korea (GOCI-II 대기상한 반사도와 기계학습을 이용한 남한 지역 시간별 에어로졸 광학 두께 산출)

  • Seyoung Yang;Hyunyoung Choi;Jungho Im
    • Korean Journal of Remote Sensing
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    • v.39 no.5_3
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    • pp.933-948
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    • 2023
  • Atmospheric aerosols not only have adverse effects on human health but also exert direct and indirect impacts on the climate system. Consequently, it is imperative to comprehend the characteristics and spatiotemporal distribution of aerosols. Numerous research endeavors have been undertaken to monitor aerosols, predominantly through the retrieval of aerosol optical depth (AOD) via satellite-based observations. Nonetheless, this approach primarily relies on a look-up table-based inversion algorithm, characterized by computationally intensive operations and associated uncertainties. In this study, a novel high-resolution AOD direct retrieval algorithm, leveraging machine learning, was developed using top-of-atmosphere reflectance data derived from the Geostationary Ocean Color Imager-II (GOCI-II), in conjunction with their differences from the past 30-day minimum reflectance, and meteorological variables from numerical models. The Light Gradient Boosting Machine (LGBM) technique was harnessed, and the resultant estimates underwent rigorous validation encompassing random, temporal, and spatial N-fold cross-validation (CV) using ground-based observation data from Aerosol Robotic Network (AERONET) AOD. The three CV results consistently demonstrated robust performance, yielding R2=0.70-0.80, RMSE=0.08-0.09, and within the expected error (EE) of 75.2-85.1%. The Shapley Additive exPlanations(SHAP) analysis confirmed the substantial influence of reflectance-related variables on AOD estimation. A comprehensive examination of the spatiotemporal distribution of AOD in Seoul and Ulsan revealed that the developed LGBM model yielded results that are in close concordance with AERONET AOD over time, thereby confirming its suitability for AOD retrieval at high spatiotemporal resolution (i.e., hourly, 250 m). Furthermore, upon comparing data coverage, it was ascertained that the LGBM model enhanced data retrieval frequency by approximately 8.8% in comparison to the GOCI-II L2 AOD products, ameliorating issues associated with excessive masking over very illuminated surfaces that are often encountered in physics-based AOD retrieval processes.

Investigation of genetic variability in commercial and invaded natural populations of red swamp crayfish(Procambarus clarkii) from South Korea (미국가재(Procambarus clarkii) 수족관 개체군 및 국내 침입 자연개체군의 유전적 변이 연구)

  • Ji Hyoun Kang;Jeong Mi Hwang;Soon-Jik Kwon;Min Jeong Baek;Sun-Jae Park;Changseob Lim;Yeon Jae Bae
    • Korean Journal of Environmental Biology
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    • v.41 no.3
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    • pp.325-334
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    • 2023
  • The invasive red swamp crayfish, Procambarus clarkii, is native to south-central United States and northeastern Mexico. Recently, it has been being spreading in the wild in South Korea. However, its primary sources, introduction routes, establishment, and expansion in South Korea remain unclear. Here, we analyzed genetic diversity and population genetic structures of its domestic natural populations during early invasion, commercial stock from local aquaria (a suspected introduction source), and original United States population using mitochondrial COI gene sequences for 267 individuals and eight microsatellite markers for 158 individuals. Natural and commercial populations of P. clarkii showed reduced genetic diversity (e.g., haplotype diversity and allelic richness). The highest genetic diversity was observed in one original source population based on both genetic markers. Despite a large number of individuals in commercial aquaria, we detected remarkably low genetic diversity and only three haplotypes among 226 individuals, suggesting an inbred population likely originating from a small founder group. Additionally, the low genetic diversity in the natural population indicates a small effective population size during early establishment of P. clarkii in South Korea. Interestingly, genetic differentiation between natural populations and the United States population was lower than that between natural populations and aquarium populations. This suggests that various genetic types from the United States likely have entered different domestic aquariums, leading to distinct natural populations through separate pathways. Results of our study will provide an insight on the level of genetic divergence and population differentiation during the initial stage of invasion of non-indigenous species into new environments.

Analysis of research trends for utilization of P-MFC as an energy source for nature-based solutions - Focusing on co-occurring word analysis using VOSviewer - (자연기반해법의 에너지원으로서 P-MFC 활용을 위한 연구경향 분석 - VOSviewer를 활용한 동시 출현단어 분석 중심으로 -)

  • Mi-Li Kwon;Gwon-Soo Bahn
    • Journal of Wetlands Research
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    • v.26 no.1
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    • pp.41-50
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    • 2024
  • Plant Microbial Fuel Cells (P-MFCs) are biomass-based energy technologies that generate electricity from plant and root microbial communities and are suitable for natural fundamental solutions considering sustainable environments. In order to develop P-MFC technology suitable for domestic waterfront space, it is necessary to analyze international research trends first. Therefore, in this study, 700 P-MFC-related research papers were investigated in Web of Science, and the core keywords were derived using VOSviewer, a word analysis program, and the research trends were analyzed. First, P-MFC-related research has been on the rise since 1998, especially since the mid to late 2010s. The number of papers submitted by each country was "China," "U.S." and "India." Since the 2010s, interest in P-MFCs has increased, and the number of publications in the Philippines, Ukraine, and Mexico, which have abundant waterfront space and wetland environments, is increasing. Secondly, from the perspective of research trends in different periods, 1998-2015 mainly carried out microbial fuel cell performance verification research in different environments. The 2016-2020 period focuses on the specific conditions of microbial fuel cell use, the structure of P-MFC and how it develops. From 2021 to 2023, specific research on constraints and efficiency improvement in the development of P-MFC was carried out. The P-MFC-related international research trends identified through this study can be used as useful data for developing technologies suitable for domestic waterfront space in the future. In addition to this study, further research is needed on research trends and levels in subsectors, and in order to develop and revitalize P-MFC technologies in Korea, research on field applicability should be expanded and policies and systems improved.

Effects of Co-digestate application on the Soil Properties, Leachate and Growth Responses of Paddy Rice (통합혐기소화액의 시용이 벼 생육 및 논토양 환경에 미치는 영향)

  • Hong, Seung-Gil;Shin, Joung-Du;Kwon, Soon-Ik;Park, Woo-Kyun;Lee, Deog-Bae;Kim, Jeong-Gyu
    • Journal of the Korea Organic Resources Recycling Association
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    • v.18 no.4
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    • pp.31-37
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    • 2010
  • Livestock manures have a potential to be a valuable resource with an efficient treatment. In Korea, 42 million tons of livestock manure were generated in 2008, and 84 % of them were used for compost and liquid fertilizer production. Recently recycling of livestock manure for biogas production through anaerobic digestion is increasing, but its utilization in agriculture is still uncertified. In this study, there was applied co-digestate to the paddy for rice cultivation based on N supplement. Co-digestate was fertilizer fermented with pig slurry and food waste combined with the ratio of 70:30(v:v) in its volumetric basis. For assessing the safety of co-digestate, it was monitored the contents of co-digestate for seasonal variation, resulted in no potential harm to the soil and plant by heavy metals. The results showed that soil applied with co-digestate was increased in exchangeable potassium, copper and zinc mainly due to the high rate of pig slurry in co-digestate applied. Considering high salt content due to the combination with food waste, strict quality assurances are needed for safe application to arable land though it has valuable fertilizer nutrient. Leachate after treatment showed that the concentration of nitrate nitrogen washed out within two weeks. Considering the salt accumulation results in soil, it is highly recommended that the application rate of co-digestate should not exceed the crop fertilization rate based on N supplement. With these results, it was concluded that co-digestate could be used as an alternative fertilizer for chemical fertilizer. More study is needed for the long-term effects of co-digestate application on the soil and water environment.

A Study on Forestation for Landscaping around the Lakes in the Upper Watersheds of North Han River (북한강상류수계(北漢江上流水系)의 호수단지주변삼림(湖水団地周辺森林)의 풍경적시업(風景的施業)에 관(関)한 연구(硏究))

  • Ho, Ul Yeong
    • Journal of Korean Society of Forest Science
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    • v.54 no.1
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    • pp.1-24
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    • 1981
  • Kangweon-Do is rich in sightseeing resources. There are three sightseeing areas;first, mountain area including Seolak and Ohdae National Parks, and chiak Provincial Park; second eastern coastal area; third lake area including the watersheds of North Han River. In this paper, several methods of forestation were studied for landscaping the North Han River watersheds centering around Chounchon. In Chunchon lake complex, there are four lakes; Uiam, Chunchon, Soyang and Paro from down to upper stream. The total surface area of the above four lakes is $14.4km^2$ the total pondage of them 4,155 million $m^3$, the total generation of electric power of them 410 thousand Kw, and the total forest area bordering on them $1,208km^2$. The bordering forest consists of planned management forest ($745km^2$) and non-planned management forest ($463km^2$). The latter is divided into green belt zone, natural conservation area, and protection forest. The forest in green belt amounts to $177km^2$ and centers around the 10km radios from Chunchon. The forest in natural conservation area amounts to $165km^2$, which is established within 2km sight range from the Soyang-lake sides. Protection forest surrounding the lakes is $121km^2$ There are many scenic places, recreation gardens, cultural goods and ruins in this lake complex, which are the same good tourist resources as lakes and forest. The forest encirelng the lakes has the poor average growing stock of $15m^3/ha$, because 70% of the forest consists of the young plantation of 1 to 2 age class. The ration of the needle-leaved forest, the broad-leaved forest and the mixed forest in 35:37:28. From the standpoint of ownership, the forest consists of national forest (36%), provincial forest (14%), Gun forest (5%) and private forest(45%). The greater part of the forest soil, originated from granite and gneiss, is much liable to weathering. Because the surface soil is mostly sterile, the fertilization for improving the soil quality is strongly urged. Considering the above-mentioned, the forestation methods for improving landscape of the North Han River Watersheds are suggested as follows: 1) The mature-stage forest should be induced by means of fertilizing and tendering, as the forest in this area is the young plantation with poor soil. 2) The bare land should be afforested by planting the rapid growing species, such as rigida pine, alder, and etc. 3) The bare land in the canyon with moderate moist and comparatively rich soil should be planted with Korean-pine, larch, ro fir. 4) Japaness-pine stand should be changed into Korean-pine, fir, spruce or hemlock stand from ravine to top gradually, because the Japanese-pine has poor capacity of water conservation and great liability to pine gall midge. 5) Present hard-wood forest, consisting of miscellaneous trees comparatively less valuable from the point of wood quality and scenerity, should be change into oak, maple, fraxinus-rhynchophylla, birch or juglan stand which is comparatively more valuable. 6) In the mountain foot within the sight-range, stands should be established with such species as cherry, weeping willow, white poplar, machilus, maiden-hair tree, juniper, chestnut or apricot. 7) The regeneration of some broad-leaved forests should be induced to the middle forest type, leading to the harmonious arrangement of the two storied forest and the coppice. 8) For the preservation of scenery, the reproduction of the soft-wood forest should be done under the selection method or the shelter-wood system. 9) Mixed forest should be regenerated under the middle forest system with upper needle-leaved forest and lower broad-leaved forest. In brief, the nature's mysteriousness should be conserved by combining the womanly elegance of the lakes and the manly grandeur of the forest.

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A Study on the Railroad Logistics Information Standardization and Information System Improvement (철도 물류 정보 표준화 방안 및 정보시스템 개선에 대한 연구)

  • Ahn, Kyeong-Rim;Kim, Dong-Hee;Park, Chan-Kwon;Park, Jung-Chun
    • The Journal of Society for e-Business Studies
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    • v.13 no.3
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    • pp.121-135
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    • 2008
  • Railroad logistics transporting freight by train takes charge of 10 or 20 percent of domestic cargos. Railroad logistics users such as transport companies including shippers or Inland Container Depot(ICD) use electronic document(EDI or XML) or input data through WEB to process railroad logistics business. However, as business environments evolving into e-business, it is required to upgrade the legacy railroad logistics process. As the increase of using ebXML-based schema format, it is also needed to improve the electronic documents based on DTD format into those of XML schema format. This study deals with information standard for railroad logistics to improve the railroad logistics business. To this purpose railroad business processes were re-defined through the standard business process modeling methodology. Information model was also derived by defining railroad logistics activities from business process model. And Business Information Entities(BIEs) were defined to design new electronic documents according to the extracted information model. An improved system architecture for railroad logistics was proposed as well. The results of this study will provide an effective and flexible business flow to railroad logistics business.

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Terrain Referenced Navigation Simulation using Area-based Matching Method and TERCOM (영역기반 정합 기법 및 TERCOM에 기반한 지형 참조 항법 시뮬레이션)

  • Lee, Bo-Mi;Kwon, Jay-Hyoun
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.28 no.1
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    • pp.73-82
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    • 2010
  • TERCOM(TERrain COntour Matching), which is the one of the Terrain Referenced Navigation and used in the cruise missile navigation system, is still under development. In this study, the TERCOM based on area-based matching algorithm and extended Kalman filter is analysed through simulation. In area-based matching, the mean square difference (MSD) and cross-correlation matching algorithms are applied. The simulation supposes that the barometric altimeter, radar altimeter and SRTM DTM loaded on board. Also, it navigates along the square track for 545 seconds with the velocity of 1000km per hour. The MSD and cross-correlation matching algorithms show the standard deviation of position error of 99.6m and 34.3m, respectively. The correlation matching algorithm is appeared to be less sensitive than the MSD algorithm to the topographic undulation and the position accuracy of the both algorithms is extremely depends on the terrain. Therefore, it is necessary to develop an algorithm that is more sensitive to less terrain undulation for reliable terrain referenced navigation. Furthermore, studies on the determination of proper matching window size in long-term flight and the determination of the best terrain database resolution needed by the flight velocity and area should be conducted.

An approach to capture travelers' choice behaviour in response to unexperienced transportation modes: A case study of Personal Rapid Transit (미경험 교통수단에 대한 이용자 선택행태 분석: Personal Rapid Transit 사례를 중심으로)

  • Yu, Jeong-Whon;Shin, Seung-Kwon;Choi, Jung-Yoon
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.1730-1738
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    • 2011
  • Personal Rapid Transit (PRT) has emerged as a promising alternative transportation mode for transit-oriented sustainable communities by creating compact and walkable environments with competitive construction and operational costs. This study seeks to capture the changes in travel mode choice behavior in response to the introduction of PRT to travelers who have no previous experience of using it. A critical issue in modeling the PRT mode choice is how to capture travelers' perception and evaluation of the unexperienced travel mode. The data used come from questionnaire surveys, in which RP (Revealed Preference) and SP (Stated Preference) data were collected in relation to travel mode choices with and without PRT systems. The questionnaire was designed especially for mitigating the potential bias in favor of or against choosing PRT. In addition, an efficient approach was proposed to reduce the number of SP questions by avoiding the complex fractional factorial design which tends to make it difficult for respondents to keep their attention throughout the survey. The analysis results show that the proposed approach is able to realistically capture the effects of explanatory variables on the travel mode choice. Discrete choice models are developed to predict travelers' mode choices under different choice scenarios by varying PRT system specifications and operational characteristics. PRT patronages are projected for two different test sites using the developed PRT mode choice models.

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What factors influence the managers' compensation stickiness (경영자 보상의 하방경직성에 영향을 미치는 요인)

  • Chi, Sung-Kwon
    • Management & Information Systems Review
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    • v.29 no.4
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    • pp.333-357
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    • 2010
  • Purposes of this paper are to investigate whether managers' compensation is sticky as accounting performance(ROA) vary or not and explore further what factors influence the managers' compensation stickiness. To empirically study the stickiness of managers' compensation, we used the financial data from manufacturing firms lised in the Korea Stock Exchange(1,000 firm-year data for 4 years). The results are as follows : First, managers' compensation is sticky with respect to change in accounting performance. That is, the increase in managers' compensation as accounting performance increases is greater than the decrease in managers' compensation in respect to equivalent decrease in accounting performance. Second, the degree of managers' compensation stickiness increases when managers have influence and contribution to firm value. Specifically, the degree of stickiness is positively associated with investment opportunity set, intangible assets' value, uncertainty of firms' operating environment, complexity of organizational hierarchy. But firms' size reversely impacts on the degree of managers' compensation stickiness.

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A Study upon Online Measurement techniques of Corporate Reputation (기업의 디지털 평판 측정 기법 연구)

  • Kim, Seung-Hee;Kim, Woo-Je;Lee, Kwang-Seok
    • Journal of the Korea Society of Computer and Information
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    • v.18 no.9
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    • pp.139-152
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    • 2013
  • Although a series of studies shows the fact that a company's reputation could affect its sales rate and stock price, due to the increased use of SNS, the research related to the online measurement method for the corporate reputation has been relatively insufficient. This study explores a design for a method to quantify the corporate reputation value by reconstructing the discussions in literature review. Concretely, this study divides the corporate reputation value into the corporate identity information and the corporate awareness information, which includes the following five sub-categories: (1) the quality of product and service; (2) the employment environment; (3) the corporate vision; (4) the social responsibility; and (5) the business achievement. Additionally, for the corporate identity assessment, this study considers the following six factors: (1) Agreeableness (Goodness), (2)Capability (Ability), (3)Enterprise (Rise), (4)Chic (Class), (5) Ruthlessness (Authority), and (6)Informality. Based on these categories and factors, this study develops a technique quantifying the corporate reputation value by selecting 'word items' for the reputation search, and after conducting a frequency analysis in a survey. Also, to verify the result, this study exemplifies the reputation of three SI companies in Korea which could be utilized by using the commercialized reputation service. This study firstly attempts the corporate reputation measurement by classifying the identity and the awareness (corporate image and communication) upon a company in detail and enables its real applicabilities by proposing a formula to measure the reputation scores which can be utilized by verified word items from a frequency analysis.