• Journal of Korean Society of Environmental Engineers
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• v.32 no.12
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• pp.1102-1110
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• 2010

Tidal mudflat is a reservoir for diverse microbial resources. Microbial diversity in tidal mudflat sediment can be easily influenced by various human activities. It is necessary to take representative samples to monitor microbial diversity in tidal mudflat sediments. In this study, we analyzed the microbial diversity and chemical characteristics of vegetation and non-vegetation tidal mudflat regions in the Kangwha tidal mudflat using geo-statistics and data-mining. According to the geo-statistical analysis, most correlation range values for the vegetation region were smaller than those for the non-vegetation region, which suggested that the shorter number and interval of sampling are required for the vegetation tidal mudflat environment due to its higher degree of chemical and biological complexity and heterogeneity. The data-mining analysis suggested that the organic content and nitrate were the major environmental factors influencing microbial diversity in the vegetation region while pH and sulfate were the major influencing factors in the non-vegetation region. Using the geo-statistical and data-mining integration approach, we proposed a guideline for determining the sampling interval and number to monitor microbial diversity in tidal mudflat.

• Journal of Environmental Policy
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• v.14 no.4
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• pp.103-123
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• 2015

To provide effective management policy of geo-heritages, concept of Korean geo-heritage has been organized based on geo-diversity, geo-conservation, geo-tourism, and earth-heritage. In addition, current status of geo-heritage in Korea has been grasped, and categorized. In case GPS (Global Positioning System) coordinates exist, spatial information was constructed as GIS (Geographic Information System). Geo-heritages were classified into a total of six categories of natural monument, scenic site, coastal sand-dune, natural cave, world nature heritage, and other types of geo-heritage. By mapping 991 geo-heritages scattered nationwide using geographical information, all statuses can now be readily identified and enable the analysis of the distribution tendencies and correlation with topography. This study was aimed at searching the political connection based on quantitatively organized and analyzed geo-heritages, which have not been mapped thus far. In addition, this study organized data that have existed only in literature, and presented example verification. Moreover, these can be used as guidelines for the future search, discovery, registration and management of geo-heritage. If additional geo-heritages are discovered in field studies or with satellite images, then more correlations may be identified and help facilitate the research on geo-heritages management plans.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.3
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• pp.445-450
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• 2015

Generally, Low Earth Orbit (LEO) satellites are used to collect image or video from earth's surface. The collected data are stored on-board and/or transmitted to the main ground station directly or via polar ground station using terrestrial line. Today, an intersatellite link between a LEO and a GEO satellite allows transmission of the collected data to the main ground station through the GEO satellite. In this study, an approach for a continuous communication starting from LEO through GEO to ground station is proposed by determining the optimum ground station locations. In doing so, diverse ground stations help to determine the GEO orbit as well. Cross-correlation of the long term daily rainfall averages are multiplied with the logarithmic correlation of the sites to calculate the joint correlation of the diverse ground station locations. The minimum values of this joint correlation yield the optimum locations of the ground stations for Q/V-band communication and satellite control operations. Results for several case studies are listed.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.120.2-120
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• 2003

Agrobacterium vitis is a causal agent of crown-gall disease on grapevine. In Korea, grapevine variety (GeoBong) have severely been infected by the bacteria since stems of the variety were buried in soil for overwintering. Infection ratio over 70-80％ was observed on 7 years old GeoBong grapevine in Ansung and Cheonan. PCR specific primers for A. vitis strains were designed using nucleotide sequences of vir A gene in Ti-Plasmid, pheA gene in chromosomal DNA and a URP-PCR polymorphic band. Three hundred bacterial strains were isolated from the different 80 galls formed on GeoBong grapevine in Cheonan and Ansung of Korea and were screened to identify A. vitis using the three specific PCR primers for Agrobacterium vitis. Twenty-four bacterial strains that are detected by the primers were further confirmed by pathogenicity and biochemical methods. To investigate the genomic diversity of the bacterial strains, twenty primers of 20 mer referred to universal rice primers (URP) were applied for PCR fingerprinting, Of them, URP2R and URP2F primers could effectively be used to detect polymorphism within the bacterial strains.

• Journal of Advanced Navigation Technology
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• v.19 no.3
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• pp.207-216
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• 2015

Since the distribution of SBAS reference stations is one of the most important factors that affect the system performance, the effects of the distribution should be analyzed carefully from the beginning of the program to develop the system conforming to given performance requirements. The reference stations of KASS, the Korean SBAS, are planned to be installed only inside South Korea, which limits the number and area of those. It differentiates KASS from others that have much larger sites. In this paper, the author analyzes the performance impact on UDRE and ${\delta}UDRE$ for GPS and GEO due to the limitations by a series of simulations, which showed that the UDRE performance depends on the diversity of the reference station distribution and the impact on the GEO UDRE is significant. The paper concludes by providing KASS design and development considerations to minimize the possible performance risks due to the limitations of KASS reference station distribution.

• Journal of the Korean GEO-environmental Society
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• v.18 no.1
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• pp.37-47
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• 2017

The Mekong River plays an extremely important role in Southeast Asia. Flowing through six countries, including China, Myanmar, Thailand, Laos PDR, Cambodia, and Vietnam, it is a site of great biological and ecological diversity and the habitat of numerous species of fish. It also supports a very large population that lives along the river basin. Therefore, much attention has been focused on the giant Mekong River Basin, particularly, its soil erosion and sedimentation problems. In fact, many methods have been used to calculate and simulate these problems. However, in the case of the Mekong River Basin, the available data is limited because of the extreme size of the area (about $795,000km^2$) and lack of equipment systems in the countries through which the Mekong River flows. In this study, we applied the Universal Soil Loss Equation (USLE) model in a GIS (Geographic Information System) framework to calculate the amount of soil erosion and sediment load during the selected period, from 1951 to 2007. The result points out dangerous areas, such as the Upper Mekong River Basin and 3S Basin (containing the Sekong, Sesan, and Srepok Rivers) that are suffering the serious consequences of soil erosion problems. Moreover, the present model is also useful for supporting river basin management in the implementation of sustainable management practices in the Mekong River Basin and other basins.

• Journal of information and communication convergence engineering
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• v.6 no.2
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• pp.129-133
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• 2008

In this paper, modified power control algorithms are proposed for a satellite mobile communications system with ATC (ancillary terrestrial component). In order to increase system capacity and reduce the transmitting power of the user's equipment, we propose the modified power control scheme consisting of the modified closed-loop and open-loop power control. The modified CLPC (closed-loop power control) algorithm, combining the delay compensation algorithms and pilot diversity, is mainly applied to the ATC link in urban areas because it is more suitable to the short RTD (round-trip delay). In the case of rural areas where ATCs are not deployed or a signal is not received from ATCs, combining monitoring transmitting power equipment and OLPC (open-loop power control) algorithms using an efficient pilot diversity is mainly applied to the link between the user's equipment and the satellite. Two power control algorithms are applied equally to the boundary areas where two kinds of signals are received in order to ensure coverage continuity. The simulation results show that the modified power control scheme has good performance compared to conventional power control schemes in a GEO (geostationary earth orbit) satellite system with ATC.

• Journal of Forest and Environmental Science
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• v.40 no.2
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• pp.111-117
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• 2024

An evaluation was carried out on variability in morphology of fruits and seeds (number and weight) of Tetrapleura tetraptera (Schumach. and Thonn.) Taub. from different populations across its distribution range in Nigeria. Bulk fruit samples were collected and examined for variations in morphological characters. Differences in morphological character of fruits and seeds among the populations were determined using analysis of variance at 5% level of probability. The relationships among morphological characters were determined using Pearson correlation coefficient (r). Significant variations (p<0.05) existed among T. tetraptera populations for all the evaluated characters: fruit length, fruit width, number of seeds per fruit and seed weight. A positive significant strong correlation (r=0.96) was found between seed weight and number of seeds per fruit, while no correlation existed between fruit length, width and number of seeds. Seed weight was positively correlated with minimum altitude (r=0.97) and maximum altitude (r=0.99) of seed populations. Number of seeds was also significantly correlated with maximum altitude (r=0.965). There was no significant correlation between geo-climatic variables and fruit dimensions (length and width). Observed variations in morphological traits within and across populations of T. tetraptera may be used as proxy to estimate genetic diversity and selection of superior trees for improved productivity.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.2
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• pp.147-156
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• 2024

The sustainable management and enhancement of marine resources are becoming increasingly important issues worldwide. This study was conducted in response to these challenges, focusing on the development and performance comparison of fish detection and classification models as part of a deep learning-based technique for assessing the effectiveness of marine resource enhancement projects initiated by the Korea Fisheries Resources Agency. The aim was to select the optimal model by training various sizes of YOLOv8-Seg models on a fish image dataset and comparing each performance metric. The dataset used for model construction consisted of 36,749 images and label files of 12 different species of fish, with data diversity enhanced through the application of augmentation techniques during training. When training and validating five different YOLOv8-Seg models under identical conditions, the medium-sized YOLOv8m-Seg model showed high learning efficiency and excellent detection and classification performance, with the shortest training time of 13 h and 12 min, an of 0.933, and an inference speed of 9.6 ms. Considering the balance between each performance metric, this was deemed the most efficient model for meeting real-time processing requirements. The use of such real-time fish detection and classification models could enable effective surveys of marine resource enhancement projects, suggesting the need for ongoing performance improvements and further research.

• Spatial Information Research
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• v.23 no.4
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• pp.33-46
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• 2015

The fact that the limits of information recency, diversity, and usability are mainly caused by the supply oriented geospatial data and service development is commonly recognized. It is recently tried to overcome the limits by facilitating user experience and VGI(Volunteered Geographic Information) in several geospatial web services. This study suggests conceptual architecture and service scenario for geospatial collaborative platform prototype through review and examination of previous researches. The prototype, composed of 4 unit modules: 3D POI Creation Module, 3D POI Application Module, 3D POI/Event Management Module, 3D POI/Event Monitoring Module, provides the capability of collaboratively dealing with geospatial work. The suggested service scenario is demonstrated by developing prototype for the service modules.