• Korean Journal of Remote Sensing
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• v.39 no.6_1
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• pp.1255-1272
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• 2023

Satellite-based chlorophyll-a concentration, produced as a long-term time series, is crucial for global climate change research. The production of data without gaps through the merging of time-synthesized or multi-satellite data is essential. However, studies related to satellite-based chlorophyll-a concentration in the waters around the Korean Peninsula have mainly focused on evaluating seasonal characteristics or proposing algorithms suitable for research areas using a single ocean color sensor. In this study, a merging dataset of remote sensing reflectance from the geostationary sensor GOCI-II and polar-orbiting sensors (MODIS, VIIRS, OLCI) was utilized to achieve high spatial coverage of chlorophyll-a concentration in the waters around the Korean Peninsula. The spatial coverage in the results of this study increased by approximately 30% compared to polar-orbiting sensor data, effectively compensating for gaps caused by clouds. Additionally, we aimed to quantitatively assess accuracy through comparison with global chlorophyll-a composite data provided by Ocean Colour Climate Change Initiative (OC-CCI) and GlobColour, along with in-situ observation data. However, due to the limited number of in-situ observation data, we could not provide statistically significant results. Nevertheless, we observed a tendency for underestimation compared to global data. Furthermore, for the evaluation of practical applications in response to marine disasters such as red tides, we qualitatively compared our results with a case of a red tide in the East Sea in 2013. The results showed similarities to OC-CCI rather than standalone geostationary sensor results. Through this study, we plan to use the generated data for future research in artificial intelligence models for prediction and anomaly utilization. It is anticipated that the results will be beneficial for monitoring chlorophyll-a events in the coastal waters around Korea.

• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.45-59
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• 2023

The global focus on mitigating climate change has traditionally centered on carbon dioxide, but recent attention has shifted towards methane as a crucial factor in climate change adaptation. Natural settings, particularly aquatic environments such as wetlands, reservoirs, and lakes, play a significant role as sources of greenhouse gases. The accumulation of organic contaminants on the lake and reservoir beds can lead to the microbial decomposition of sedimentary material, generating greenhouse gases, notably methane, under anaerobic conditions. The escalation of methane emissions in freshwater is attributed to the growing impact of non-point sources, alterations in water bodies for diverse purposes, and the introduction of structures such as river crossings that disrupt natural flow patterns. Furthermore, the effects of climate change, including rising water temperatures and ensuing hydrological and water quality challenges, contribute to an acceleration in methane emissions into the atmosphere. Methane emissions occur through various pathways, with ebullition fluxes-where methane bubbles are formed and released from bed sediments-recognized as a major mechanism. This study employs Biochemical Methane Potential (BMP) tests to analyze and quantify the factors influencing methane gas emissions. Methane production rates are measured under diverse conditions, including temperature, substrate type (glucose), shear velocity, and sediment properties. Additionally, numerical simulations are conducted to analyze the relationship between fluid shear stress on the sand bed and methane ebullition rates. The findings reveal that biochemical factors significantly influence methane production, whereas shear velocity primarily affects methane ebullition. Sediment properties are identified as influential factors impacting both methane production and ebullition. Overall, this study establishes empirical relationships between bubble dynamics, the Weber number, and methane emissions, presenting a formula to estimate methane ebullition flux. Future research, incorporating specific conditions such as water depth, effective shear stress beneath the sediment's tensile strength, and organic matter, is expected to contribute to the development of biogeochemical and hydro-environmental impact assessment methods suitable for in-situ applications.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.3
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• pp.215-231
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• 2020

Forest landscape models (FLMs) can be used to investigate the complex interactions of various ecological processes and patterns, which makes them useful tools to evaluate how environmental and anthropogenic variables can influence forest ecosystems. However, due to the large spatio-temporal scales in FLMs studies, parameterization and validation can be extremely challenging when applying to new study areas. To address this issue, we focused on the parameterization and application of a spatially explicit forest landscape model, LANDIS-II, to Mt. Gyebang, South Korea, with the use of the National Forest Inventory (NFI) and long-term ecological research (LTER) site data. In this study, we present the followings for the biomass succession extension of LANDIS-II: 1) species-specific and spatial parameters estimation for the biomass succession extension of LANDIS-II, 2) calibration, and 3) application and validation for Mt. Gyebang. For the biomass succession extension, we selected 14 tree species, and parameterized ecoregion map, initial community map, species growth characteristics. We produced ecoregion map using elevation, aspect, and topographic wetness index based on digital elevation model. Initial community map was produced based on NFI and sub-alpine survey data. Tree species growth parameters, such as aboveground net primary production and maximum aboveground biomass, were estimated from PnET-II model based on species physiological factors and environmental variables. Literature data were used to estimate species physiological factors, such as FolN, SLWmax, HalfSat, growing temperature, and shade tolerance. For calibration and validation purposes, we compared species-specific aboveground biomass of model outputs and NFI and sub-alpine survey data and calculated coefficient of determination (R²) and root mean square error (RMSE). The final model performed very well, with 0. 98 R² and 8. 9 RMSE. This study can serve as a foundation for the use of FLMs to other applications such as comparing alternative forest management scenarios and natural disturbance effects.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.4
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• pp.307-316
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• 2010

Complex terrain refers to irregular surface properties of the earth that influence gradients in climate, lateral transfer of materials, landscape distribution in soils properties, habitat selection of organisms, and via human preferences, the patterning in development of land use. Complex terrain of mountainous areas represents ca. 20% of the Earth's terrestrial surface; and such regions provide fresh water to at least half of humankind. Most major river systems originate in such terrain, and their resources are often associated with socio-economic competition and political disputes. The goals of the TERRECO-IRTG focus on building a bridge between ecosystem understanding in complex terrain and spatial assessments of ecosystem performance with respect to derived ecosystem services. More specifically, a coordinated assessment framework will be developed from landscape to regional scale applications to quantify trade-offs and will be applied to determine how shifts in climate and land use in complex terrain influence naturally derived ecosystem services. Within the scope of TERRECO, the abiotic and biotic studies of water yield and quality, production and biodiversity, soil processing of materials and trace gas emissions in complex terrain are merged. There is a need to quantitatively understand 1) the ecosystem services derived in regions of complex terrain, 2) the process regulation occurred to maintain those services, and 3) the sensitivities defining thresholds critical in stability of these systems. The TERRECO-IRTG is dedicated to joint study of ecosystems in complex terrain from landscape to regional scales. Our objectives are to reveal the spatial patterns in driving variables of essential ecosystem processes involved in ecosystem services of complex terrain region and hence, to evaluate the resulting ecosystem services, and further to provide new tools for understanding and managing such areas.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.281-302
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• 2023

Carbon is not only an essential element for life but also a key player in climate change. The radiocarbon (¹⁴C) analysis using accelerator mass spectrometry (AMS) is a powerful tool not only to understand the carbon cycle but also to track pollutants derived from fossil carbon, which have a distinct radiocarbon isotope ratio (Δ¹⁴C). Many studies have reported Δ¹⁴C of carbon compounds in streams, rivers, rain, snow, throughfall, fine particulate matter (PM_2.5), and wastewater treatment plant effluents in South Korea, which are reviewed in this manuscript. In summary, (1) stream and river carbon in South Korea are largely derived from the chemical weathering of soils and rocks, and organic compounds in plants and soils, strongly influenced by precipitation, wastewater treatment effluents, agricultural land use, soil water, and groundwater. (2) Unprecedentedly high Δ¹⁴C of precipitation during winter has been reported, which can directly and indirectly influence stream and river carbon. Although we cannot exclude the possibility of local contamination sources of high Δ¹⁴C, the results suggest that stream dissolved organic carbon could be older than previously thought, warranting future studies. (3) The ¹⁴C analysis has also been applied to quantify the sources of forest throughfall and PM_2.5, providing new insights. The ¹⁴C data on a variety of ecosystems will be valuable not only to track the pollutants derived from fossil carbon but also to improve our understanding of climate change and provide solutions.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.147-157
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• 2018

With the rapid development of the 4th industrial revolution, the large-sized facilities of agriculture have been developed with high-technologies. However, it is difficult to maintain the optimum environment in large-sized facilities. Although it is essential to control micro-climate properly in large-sized facilities, there are a lot of problems to utilize high-technologies and equipment because of insufficient education for farmers. Most farms have limitations to access to their farm because of prevention of epidemics, exposure of management know-how, and so on. Especially, it is difficult to understand internal environmental factors (airflow, temperature, humidity, etc.) for farmers because these factors are invisible. Recently, Virtual reality technology which allows users to experience various phenomena directly is attracting attention. Virtual reality is very useful technology to visualize airflow and temperature distribution and so on. However, there is no cases applied this technology to agricultural facilities. In this study, research trends of virtual reality in various fields were investigated. In particular, the limitation and possibility of virtual reality technology were analyzed for educating farmers. Finally, the development of virtual reality contents for smart-farm facility were suggested.

• The Journal of Engineering Geology
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• v.24 no.3
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• pp.431-440
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• 2014

Since the establishment of the Groundwater Act in Korea in 1993, the national policy on groundwater has focused on the preservation and management of groundwater, which should be used only as a subsidiary water resource. However, population growth, increased water demand, climate change, and the need for uniform water distribution have brought changes to groundwater policy, and have led to the prioritization of development projects such as groundwater dams and river bank filtration. Population growth, changes to the water environment, and increased water risks have all played a role in triggering rapid growth within the water industry; the size of the investment in water resources will also continue to increase worldwide. Until now, private wells and bottled mineral water have led the groundwater industry in South Korea. However, a new area of the groundwater industry, which includes the health and medical sciences, employs groundwater properties derived from regional geology, and is growing. This requires the advancement of groundwater research and technical development connected with ICT (Information and Communication Technology) and medical science, and that the public development of groundwater and its various applications is expanded through locating groundwater in the core of the water industry cluster.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.800-805
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• 2016

Rapid growth in nanotechnologies promises novel benefits through the exploitation of their unique industrial applications. However, as the production volume of nanomaterials increases, their unintentional exposure to the environment has been occured. Potential impacts of nanoproducts on the environment can be evaluated in the life cycle assessment (LCA). LCA is the systematic analysis of the resource usages and emissions over the life time from the primary resources to the moment of disposal. In this study, we performed LCA for fabrication processes of superhydrophilic oil/water separator using nano-$TiO_2$. $TOTAL^{TM}$ freeware was used to analyze for all fabrication processes, and 6-environmental impact factors (resource depletion, climate change, ozone depletion, acidification, eutropication, and photochemical oxidation) were introduced. In addition, the use of nano-$TiO_2$ in the fabrication of superhydrophilic oil/water separator was actively contributed to the environmental impact factors, compared to the bulk-$TiO_2$.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.3
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• pp.303-321
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• 2011

The availability and efficient use of the feed resources in Asia are the primary drivers of performance to maximise productivity from animals. Feed security is fundamental to the management, extent of use, conservation and intensification for productivity enhancement. The awesome reality is that current supplies of animal proteins are inadequate to meet human requirements in the face of rapidly depleting resources: arable land, water, fossil fuels, nitrogenous and other fertilisers, and decreased supplies of cereal grains. The contribution of the ruminant sector lags well behind that of non-ruminant pigs and poultry. It is compelling therefore to shift priority for the development of ruminants (buffaloes, cattle, goats and sheep) in key agro-ecological zones (AEZs), making intensive use of the available biomass from the forage resources, crop residues, agro-industrial by-products (AIBP) and other non-conventional feed resources (NCFR). Definitions are given of successful and failed projects on feed resource use. These were used to analyse 12 case studies, which indicated the value of strong participatory efforts with farmers, empowerment, and the benefits from animals of productivity-enhancing technologies and integrated natural resource management (NRM). However, wider replication and scaling up were inadequate in project formulation, including systems methodologies that promoted technology adoption. There was overwhelming emphasis on component technology applications that were duplicated across countries, often wasteful, the results and relevance of which were not clear. Technology delivery via the traditional model of research-extension linkage was also inadequate, and needs to be expanded to participatory research-extension-farmer linkages to accelerate diffusion of technologies, wider adoption and impacts. Other major limitations concerned with feed resource use are failure to view this issue from a farming systems perspective, strong disciplinary bias, and poor links to real farm situations. It is suggested that improved efficiency in feed resource use and increased productivity from animals in the future needs to be cognisant of nine strategies. These include priorities for feed resource use; promoting intensive use of crop residues; intensification of integrated ruminant-oil palm systems and use of oil palm by-products; priority for urgent, wider technology application, adoption and scaling up; rigorous application of systems methodologies; development of adaptation and mitigation options for the effects of climate change on feed resources; strengthening research-extension-farmer linkages; development of year round feeding systems; and striving for sustainability of integrated farming systems. These strategies together form the challenges for the future.

• Korean Journal of Remote Sensing
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• v.34 no.2_2
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• pp.307-311
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• 2018

It is necessary to establish wide integrated surveillance system of marine territory to reduce damage caused by maritime security threats, marine pollution and accidents for safe and clean marine use and efficient development of marine resources. For marine surveillance, the information characteristics of space-time specific, accuracy and operability are required, and real-time information about the wide area should be provided at all times. This special issue has been published to identify the characteristics of each platform, evaluate its usability for the establishment of a wide integrated surveillance system, and present the direction for future convergence studies between platforms. Since 2015, KIOST and cooperative research team have been performing the project, "Base research for building wide integrated surveillance system of marine territory using multi-platform" that detect vessels and red tide etc. near real time by using satellite, UAV and HF Ocean Radar. The objective of this special issue is to introduce the significance for an integrated system for maritime surveillance and to create a forum for discussion on recent advances in remote sensing technology and applications for marine disasters, pollution, and accident surveillance.