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Goyang, South Korea

Kim J.-H.,GEO C and I Co. | Gang S.-M.,U and G I and T Co. | Kim J.-M.,SOC Research Institute | Jang S.-H.,GEO C and I Co.
ACRS 2015 - 36th Asian Conference on Remote Sensing: Fostering Resilient Growth in Asia, Proceedings

The recent construction of geographic information system (GIS) is developed in the 3D direction. 3D analysis and development of GIS are supported by XDworld, JoyMap and other domestic commercial engines, as well as by diverse overseas commercial engines. Also, open-source 3D display engines, including World Wind provided by NASA, are increasingly used for the development of GIS. Open-source-based GIS engines are cheap, and offer high freedom of development, giving them an advantage, while they are difficult to manage after development and require the developer itself to shoot troubles, giving them a disadvantage. Also, commercial GIS development engines are convenient to manage after development, and possible problems can be resolved in association with the developers of the engines, while they are expensive and the development scope is limited by the developers of engines. The most important thing for the development of system is the freedom of development and follow-up management of the system, and as such, conventional engines cannot possibly cover all these requirements. To overcome these limitations, game engine-based GIS development is recently in the spot, because game engines are cheap and offer high freedom of development. Thus, this study examines existing game engine-linked GIS development cases and presents the method of implementing the game engine-based GIS. 3D GI-linked game engines can be used to simulate a wealth of information, and to employ multi-layered mash-up technology, etc. Source

Lee C.,SOC Research Institute | Park S.,Korea University | Lee D.,Korea University | Lee I.-M.,Korea University | Choi H.,Korea University
Applied Clay Science

Due to its high swelling potential and low hydraulic conductivity, the bentonite-based grout has been popularly used to backfill a borehole constructed for a closed-loop vertical ground heat exchanger in a geothermal heat pump system. In this study, three types of bentonites were compared in terms of viscosity and thermal conductivity. With the consideration of the groundwater inflow, the viscosity and thermal conductivity of the bentonite grouts having bentonite contents of 5%, 10%, 15%, 20% and 25% by weight were also examined. To evaluate the effect of salinity in the coastal area on the swelling potential of the bentonite, volume reduction tests were performed. And in order to reproduce the particle segregation of bentonite-sand mixture when the bentonite-based grout has relatively low viscosity, the segregation was observed using a ring-type separable test apparatus. © 2014 Elsevier B.V. Source

Min D.-J.,Sungkyunkwan University | Jung M.-R.,Sungkyunkwan University | Kim M.-Y.,Sungkyunkwan University | Kwark J.-W.,SOC Research Institute
International Journal of Structural Stability and Dynamics

The purpose of this paper is to develop a detailed 3D maglev vehicle and guideway model and investigate the dynamic response characteristics of the coupled system. For this, the maglev vehicle is modeled as one cabin and four bogies having eight electromagnetics, four sensors, and four secondary suspensions based on the Urban Transit Maglev (UTM) system in Korea. The 3D dynamic equilibrium equations of the cabin and bogies are derived by considering the actively controlled electromagnetic forces. Also, the equations of motion for the guideway are derived using the modal superposition method for vertical, lateral, and torsional modes. The resulting coupled equations of motion are then solved using a predictor–corrector iterative algorithm. Finally, through the numerical simulation of the developed system, the responses using the 3D maglev vehicle model are compared with those obtained by the corresponding 2D model. The effects of surface irregularity on the dynamic interaction behaviors are then evaluated for increasing vehicle speeds. Particularly, the 3D resonance conditions of the guideway girder and the maglev vehicle are presented considering the resonance conditions due to equidistant moving loads. In addition, some resonance phenomena are rigorously explored, including the lateral resonance by a series of vehicles running on a girder. © 2016 World Scientific Publishing Company Source

Min J.,SOC Research Institute | Yi J.-H.,Korea Advanced Institute of Science and Technology | Yi J.-H.,Korea Maritime and Ocean University | Yun C.-B.,Ulsan National Institute of Science and Technology
Smart Structures and Systems

Jacket-type offshore structures are always exposed to severe environmental conditions such as salt, high speed of current, wave, and wind compared with other onshore structures. In spite of the importance of maintaining the structural integrity for an offshore structure, there are few cases to apply a structural health monitoring (SHM) system in practice. The impedance-based SHM is a kind of local SHM techniques and to date, numerous techniques and algorithms have been proposed for local SHM of real-scale structures. However, it still requires a significant challenge for practical applications to compensate unknown environmental effects and to extract only damage features from impedance signals. In this study, the impedance-based SHM was carried out on a 1/20-scaled model of an Uldolmok current power plant structure in Korea under changes in temperature and transverse loadings. Principal component analysis (PCA)-based approach was applied with a conventional damage index to eliminate environmental changes by removing principal components sensitive to them. Experimental results showed that the proposed approach is an effective tool for long-term SHM under significant environmental changes. Copyright © 2015 Techno-Press, Ltd. Source

Kim Y.J.,University of Colorado at Denver | Kang J.-Y.,SOC Research Institute | Park J.-S.,SOC Research Institute | Jung W.-T.,SOC Research Institute
Journal of Bridge Engineering

This paper presents the effect of corrosion damage on the service response of prestressed concrete bridge girders strengthened with posttensioned near-surface-mounted (NSM) carbon fiber-reinforced polymer (CFRP) strips. Three-dimensional finite-element modeling, validated against experimental data, is conducted to deterministically study the static and dynamic behavior of the girders subjected to chloride-induced corrosion for a period of 100 years. With an increase in corrosion damage, the efficacy of the posttensioned NSM CFRP augments from a serviceability perspective. Modal analysis identifies critical regions along the girder where strain localization occurs at certain dynamic excitation frequencies. The unstrengthened girders are more reactive to dynamic responses than their strengthened counterparts; however, both exhibit similar ride quality. Corrosion damage significantly decreases the equivalent flexural rigidity of the decrepit girders up to 30% relative to that of the control girders. The level of damage and the extent of the total potential for the strengthened girders are correlated with the magnitude of their fundamental frequencies. © 2015 American Society of Civil Engineers. Source

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