• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2004.11a
• /
• pp.211-218
• /
• 2004

The WAM wave model has been widely used for wave hindcasting in the ocean by many domestic and foreign researchers due to its relative simplicity and high accuracy. As this model was originally developed for the condition cf deepwater and comparatively coarse grid size covering wide area, it might produce in a fault result mused by the improper distribution of directional spreading. We extensively investigated involved problems based on WAM Cycle 4 model and suggested the improved WAM model so that it is applicable to both shallow water sea and fine mesh wave simulation. The modified WAM model is verified here by comparing the computed result with and the observed data at Ieodo Ocean Research Station for September of 2003.

• Tunnel and Underground Space
• /
• v.16 no.1 s.60
• /
• pp.38-49
• /
• 2006

LNG storage in lined rock cavern demands various techniques concerned with rock mechanics, thermo-mechanics and hydrogeology in design, construction and maintenance stage. LNG pilot cavern was constructed in Daejeon in order to verify these techniques. In this paper, evaluation of drainage system and ice ring formation was studied by numerical simulation. By Modflow analysis in the viewpoint of aquifer and Seep/W analysis in the viewpoint of flow system, it was verified that the drainage system in the pilot cavern was efficiently operated. Since ice ring formation can be simulated by interactive relation between heat transfer and water flow, coupled analysis of those was performed. In this analysis, the position of ice ring was presumed and it was demonstrated that the formation is affected by velocity and direction of groundwater flow.

• Journal of Navigation and Port Research
• /
• v.28 no.6
• /
• pp.557-564
• /
• 2004

The WAM wave model has been widely used for wave hindcasting in the ocean by many domestic and foreign researchers due to its relative simplicity and high accuracy. As this model was originally developed for the condition of deepwater and comparatively coarse grid size covering wide area, it might produce in a fault result caused by the improper distribution of directional spreading. We extensively investigated involved problems based on WAM Cycle 4 model and suggested the improved WAM model so that it is applicable to both shallow water sea and fine mesh wave simulation The modified W AM model is verified here by comparing the computed result with and the observed data at Ieodo Ocean Research Station for September of 2003.

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

• Journal of the Korean Geotechnical Society
• /
• v.36 no.8
• /
• pp.17-25
• /
• 2020

Korea Institute of Civil Engineering and Building Technology has constructed a large scale Dust Thermal Vacuum Chamber to simulate extreme lunar terrestrial environments and to study the Moon as an outposts for space development and exploration. Although a large amount of KLS-1 (Korean Lunar Simulant-1) is required for research, its massive production is practically difficult. This paper describes semi-automatic manufacturing system for massive production of KLS-1 in detail, which is seven times more efficient than manual production. In addition, to increase the similarity with lunar regolith, hydrogen reduction reaction using ilmenite which is one of the minerals was also conducted to simulate nanophase Fe(0) which is the unique property of lunar regolith. As a result, it was found that np-Fe(0) was formed at a temperature of 700℃ or higher, and increased in proportion to the temperature until 900℃.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.3 no.1
• /
• pp.45-58
• /
• 1993

Owing to consecutive start of operation of large-scale coal-fired power plants in Korea, the ash production amounts to about 2 million tons per year. The impact of rising disposal costs, looming environmental problems and increased ash tonnages has heightened the concerns about coal ash utilization. The paper mainly describes the correlation between bending strength and microstructure of brick body from fly ash and clay mixture. The results show that bending strength depends mainly on the size and quantity of pore, the sinterability of matrix, and the crack due to the coarse quarts grain, and that the brick body added 15 wt.% fly ash has the best bending strength over the whole firing range.

• Korean Journal of Remote Sensing
• /
• v.32 no.3
• /
• pp.253-262
• /
• 2016

Here, we estimated daily Photosynthetically Available Radiation (PAR) from Geostationary Ocean Colour Imager (GOCI) and compared it with daily PAR derived from polar-orbiting MODIS images. GOCI-based PAR was also validated with in-situ measurements from ocean research station, Socheongcho. GOCI PAR showed similar patterns with in-situ measurements for both the clear-sky and cloudy day, whereas MODIS PAR showed irregular patterns at cloudy conditions in some areas where PAR could not be derived due to the clouds of sunglint. GOCI PAR had shown a constant difference with the in-situ measurements, which was corrected using the in-situ measurements obtained on the days of clear-sky conditions at Socheongcho station. After the corrections, GOCI PAR showed a good agreement excepting on the days with so thick cloud that the sensor was optically saturated. This study revealed that GOCI can estimate effectively the daily PAR with its advantages of acquiring data more frequently, eight times a day at an hourly interval in daytime, than other polar orbit ocean colour satellites, which can reduce the uncertainties induced by the existence and movement of the cloud and insufficient images to map the daily PAR at the seas around Korean peninsula.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.9 no.3
• /
• pp.123-135
• /
• 2006

In this study, in order to maximize the accuracy and efficiency of the existing interpolation method fractal methods are applied. Developed FEDISA model revives the irregularity of the real topography with only a few information about base topography, which can produce almost complete geographic information. Moreover, as a tool for examining the adaptability and efficiency of the model, index of slope range $I_{SR}$, index of surface $I_{SA}$, and index of volume $I_V$ were developed. The model area is respectively set to $75m{\times}75m$, $150m{\times}150m$, $300m{\times}300m$, $600m{\times}600m$, and $1,200m{\times}1,200m$, and then the data obtained by combining the existing interpolation methods and FEDISA model were compared with real measurements. The result of the study showed the adaptability and efficiency of FEDISA model in topography restoration.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38B no.10
• /
• pp.801-807
• /
• 2013

WSN consists of hundreds to thousands of sensor nodes. In order to solve the problem of energy consumption imbalance cluster head is reelected in every round, while node authentication scheme is utilized for secure communication. However, re-clustering increases the overhead of sensor nodes and during the node authentication phase the frequent AREQ/AREP message exchange also increases the overhead. Therefore, a secure and energy efficient protocol, by which overhead of sensor nodes is reduced and long time communication is achieved, is required for wireless sensor network. In this paper, an energy efficient and reliable IDE-LEACH protocol for WSN is proposed. The proposed protocol is prolongs networks lifetime about average 20% compared to the LEACH-based protocols and all attending nodes in communication form BS authentication consisted of trusted nodes.

• Journal of the Korean Geotechnical Society
• /
• v.38 no.9
• /
• pp.19-33
• /
• 2022

Planarity geotechnical exploration missions were actively performed during the 1970s and there was a period of decline from the 1 990s to the 2000s because of budget. However, exploring space resources is essential to prepare for the depletion of Earth's resources in the future and explore resources abundant in space but scarce on Earth, such as rare earth and helium-3. Additionally, the development of space technology has become the driving force of future industry development. The competition among developed countries for exoplanet exploration has recently accelerated for the exploration and utilization of space resources. For these missions and resource exploration/mining, geotechnical exploration is required. There have been several missions to explore exoplanet ground, including the Moon, Mars, and asteroids. There are Apollo, LUNA, and Chang'E missions for exploration of the Moon. The Mars missions included Viking, Spirit/Opportunity, Phoenix, and Perseverance missions, and the asteroid missions included the Hayabusa missions. In this study, space planetary mineral resource exploration technologies are explained, and the future technological tasks of Korea are described.