• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.5
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• pp.451-457
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• 2011

A short laser pulse irradiates a sample to create the highly energetic plasma that emits light of a specific wavelength peak according to the material. By identifying different peaks for the analyzed samples, its chemical composition can be rapidly determined. The LIBS (Laser-Induced Breakdown Spectroscopy) has great advantages as an elemental analyzer on board a space rover, namely real-time rapid analysis and stand-off detection. The LIBS signal intensity is remarkably increased by using double-pulse LIBS system for component analysis of lunar environments where the surrounding pressure is low. Also the angle of target is adjusted for replicating arbitrary shapes of the specimen.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.4
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• pp.21-30
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• 2007

This study aims to understand the characteristics of dangsan forests and rural community forests (RCF), and seek for a landscape management scheme. Dangsan forests and RCF have been maintained by local residents since hundreds of years ago. However, many of them have been disturbed. The case sites were derived from the twenty villages previous investigated where dangsan forests and RCF's remainrd. The two sites were remodelled to restore what have been degraded. Hanbam village has maintained its dangsan forest with good management practices, whereas the dangsan forest and RCF of Goiran village showed relatively poor management. The size of dangsan forest at hanbam village was 13,784$m^2$, and major tree species was Pinus densiflora. In total, 151 trees with more than 30cm in DBH were standing on the site. As a cultural activity, the dangsan festival have been held in January $5^{th}$ by lunar calendar to the 2005 at the Jindongdan, a dangsan tree made of stone. The RCF of Hanbam village has disappeared due to the event of landslide in 1930, which needs to be restored. Goiran village has a dangsan forest and a RCF. The forests in Goiran village revealed many problems due to bad management practice. The prototype of the dangsan forest was deteriorated by introduced Prunus serrulata and the facilities for physical training. A systematic management scheme for dangsan forests and RCF's should be established with a close partnership among local residents, experts, and local government.

• Journal of Korea Water Resources Association
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• v.56 no.11
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• pp.775-784
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• 2023

With the increasing trend of extreme rainfall that exceeds the design frequency of man-made structures due to extreme weather, it is necessary to review the safety of agricultural reservoirs designed in the past. However, there are no local government-managed reservoirs (13,685) that can be discharged in an emergency, except for reservoirs over a certain size under the jurisdiction of the Korea Rural Affairs Corporation. In this case, it is important to quickly deploy a mobile siphon to the site for preliminary discharge, and this study evaluated the applicability of a mobile siphon with a diameter of 200 mm, a minimum water level difference of 6 m, 420 (m²/h), and 10,000 (m²/day), which can perform both preliminary and emergency discharge functions, to the Yugum Reservoir in Gyeongju City. The test bed, Yugum Reservoir, is a facility that was completed in 1945 and has been in use for about 78 years. According to the hydrological stability analysis, the lowest height of the current dam crest section is 27.15 (EL.m), which is 0.29m lower than the reviewed flood level of 27.44 (EL.m), indicating that there is a possibility of lunar flow through the embankment, and the headroom is insufficient by 1.72 m, so it was reviewed as not securing hydrological safety. The water level-volume curve was arbitrarily derived because it was difficult to clearly establish the water level-flow relationship curve of the reservoir since the water level-flow measurement was not carried out regularly, and based on the derived curve, the algorithm for operating small and medium-sized old reservoirs was developed to consider the pre-discharge time, the amount of spillway discharge, and to predict the reservoir lunar flow time according to the flood volume by frequency, thereby securing evacuation time in advance and reducing the risk of collapse. Based on one row of 200 mm diameter mobile siphons, the optimal pre-discharge time to secure evacuation time (about 1 hour) while maintaining 80% of the upper limit water level (about 30,000 m²) during a 30-year flood was analyzed to be 12 hours earlier. If the pre-discharge technology utilizing siphons for small and medium-sized old reservoirs and the algorithm for reservoir operation are implemented in advance in case of abnormal weather and the decision-making of managers is supported, it is possible to secure the safety of residents in the risk area of reservoir collapse, resolve the anxiety of residents through the establishment of a support system for evacuating residents, and reduce risk factors by providing risk avoidance measures in the event of a reservoir risk situation.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.3
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• pp.82-91
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• 2007

Rural areas dominate country landscape, where the population is rich in traditional and natural heritage. Dangsan forests and Rural community forests (RCF) have been maintained by local residents for hundreds of years. However, many of these forests have been disturbed, and only small amount of Dangsan forests and the RCF remain due to the efforts of local residents. Recently, the remnants of Dangsan forests and RCF have been regarded as living traditional landscapes representing the cultural and rural background of Korea. But the value of Dangsan forests and the RCFs has not been recognized by many. This study aims to understand the characteristics and management status of Dangsan forests in Sungnam-ri, Wonju. Sungnam-ri has four villages, each of which is bordered by a Dangsan forest at the riparian buffer. Sungnam-ri has been selsected as a site for a rural village development project by the Ministry of Agriculture & Forestry of Korea. Sunghwanglim (the Upper Dangsan forest) is designated as Natural Monument No.93 and entrance is limited in this area. The size of Sunghwanglim is $21,133m^2$, and the major tree species are Kalopanax pictus (Dangsan tree, Divine tree), Pinus densiflora, Abies holophylla, Acer triflorum, Ulmus davidiana, Fraxinus rhynchophylla and Quercus serrata. In total, 124 trees with more than 40 cm in DBH are at this site. As for cultural activities, the Dangsan festival is held on April 8th and September 9th of the lunar calendar at shrines in the forests. Although other Dangsan forests are smaller than Sunghwanglim, they also have similar cultural activities. The landscape of the Dangsan forests have been managed for several hundred years by the local people, and they intend to continue maintaining the Dangsan forests for the purpose of festivals and other cultural activities. The findings in this study suggest that Dangsan forests have the potential for the development of rural villages and for the improvement of cultural and natural landscapes in Korea.

• Journal of Korea Water Resources Association
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• v.47 no.9
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• pp.753-766
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• 2014

The future mean sea level rise (MSLR) due to climate change in major harbors of Korean Peninsula has been estimated by some statistical methods in this article. Firstly, Mann-Kendall non-parametric trend test to find some trend in the observed long-term tidal data has been performed and also Bayesian change point analysis has been used also to detect the location of change points and their magnitude quantitatively. Especially, in this study, the results from Bayesian change point analysis have been applied to combine 4 future MSLR scenario projections with local MSLR data at 5 tidal gauges. This proposed procedure including Bayesian change point analysis results can improve the step for the determination of starting years of future MLSR scenario projections with 18.6-year lunar node tidal cycle and effectively consider local characteristics at each gauge. The final results by the proposed procedure in this study have shown that the future MSLR in Jeju region (Jeju tidal gauge) is in the largest increment and also the future MSLRs in Western region (Boryeong tidal gauge) and Southern region (Busan tidal gauge) are in the second largest one. Finally, it has been shown that the future MSLRs in Southern region (Yeosu tidal gauge) and Eastern region (Sokcho tidal gauge) seem to be in the relatively smallest growth among 5 gauges.

• Journal of the Korean Geotechnical Society
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• v.37 no.2
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• pp.5-17
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• 2021

The Moon has been an attractive planet as an outpost for deep space exploration since He-3 and water ice which can be used as energy resources were discovered. In-Situ Resource Utilization (ISRU) construction material fabrication method is required for sustainable space planet exploration. In this paper, the possibility of microwave sintering technology for construction material fabrication was evaluated using lunar regolith that can be easily collected from the Moon surface. Experimental assessment of the influence factors on microwave sintering was conducted using a hybrid sintering system for efficient processing. The heat distribution in the furnace was observed using thermal paper that is coated with a material formulated to change color when exposed to heat. Based on this result, sintered cylindrical KLS-1s with a diameter of 1 cm and a height of 2 cm were fabricated. Densities were measured for the sintered KLS-1s under rotating turntable conditions that have an effect of microwave dispersion. The more dielectrics were arranged, the more microwaves were dispersed reducing the heat concentration, and thus a uniformity of sintered KLS-1s was enhanced.