• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.371-378
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• 2001

To enhance seismic performance of a structure ATC-40 and FEMA-273 propose technical strategies such as increasing strength, altering stiffness, and reducing demand by employing base isolation and energy dissipation devices. Specifically the energy dissipation devices directly increase the ability of the structure to dampen earthquake response. However nonlinear dynamic time history analysis of a structure with energy dissipation devices is complicated and time consuming. In this study a simple and straightforward procedure is developed using effective damping ratio to obtain the required amount of viscoelastic dampers in order to meet given performance objectives. Parametric study has been performed for the period of the structure, yield strength, and the stiffness after the first yield. According to the analysis results, earthquake demand and required damping ratio were reduced by installing viscoelastic dampers. The results also show that with the addition of the supplemental damping evaluted by the proposed method the performance of the model structures are well restrained within the target point.

• Journal of Ship and Ocean Technology
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• v.3 no.1
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• pp.12-26
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• 1999

A new concept of collision energy absorbing system for ;he New Oil-tankers with Advanced Double Hull Structure(NOAHS and NOAHS II) are presented through the joint-research pro-gran between Inha and Hamburg-Harburg University. A comparative study on col vision resistance of these proposed side structures with standard double hull structure of 310K DWT class VLCC, is carried out. The fatigue investigation of structural detail parts is also included. It contains a comparative fatigue study based on pertinent regulations of Classification Societies.

• Journal of the Korean Ceramic Society
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• v.52 no.5
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• pp.344-349
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• 2015

An interconnect is the key component of solid oxide fuel cells that electrically connects unit cells and separates fuel from oxidant in the adjoining cells. To improve their surface stability in high-temperature oxidizing environments, metallic interconnects are usually coated with conductive oxides. In this study, lanthanum nickelates ($LaNiO_3$) with a perovskite structure are synthesized and applied as protective coatings on a metallic interconnect (Crofer 22 APU). The partial substitution of Co, Cu, and Fe for Ni improves electrical conductivity as well as thermal expansion match with the Crofer interconnect. The protective perovskite layers are fabricated on the interconnects by a slurry coating process combined with optimized heat-treatment. The perovskite-coated interconnects show area-specific resistances as low as $16.5-37.5m{\Omega}{\cdot}cm^2$ at $800^{\circ}C$.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.12
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• pp.999-1006
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• 2014

Mindlin plate theory includes the shear deformation and rotatory inertia effects which cannot be negligible as exciting frequency increases. The statistical methods such as energy flow analysis(EFA) and statistical energy analysis(SEA) are very useful for estimation of structure-borne sound of various built-up structures. For the reliable vibrational analysis of built-up structures at high frequencies, the energy transfer relationship between out-of-plane waves and in-plane waves exist in Mindlin plates coupled at arbitrary angles must be derived. In this paper, the new wave transmission analysis is successfully performed for various energy analyses of Mindlin plates coupled at arbitrary angles.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.825-848
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• 2022

This paper analyzed the factors for increasing energy consumption in the domestic manufacturing sector using the LMDI (Log mean division index) decomposition method for the period from 1999 to 2019. Among the LMDI decomposition analysis methods, both additive and multiplicative factor decomposition methods were used. in this analysis. According to the result of the analysis, the factor that increased energy consumption in the domestic manufacturing industry was the production effect, and the structure effect and intensity effect were found to be the factors that decreased energy consumption. In particular, the reduction of energy consumption due to the structure effect was greater than that of energy consumption effect due to the intensity effect. By period, it can be seen that energy consumption increased rapidly due to the production effect until 2011, but after that, the increase in energy consumption due to the production effect slowed down. On the other hand, after that, the energy reduction effect due to the structure effect and the intensity effect became prominent. In order to save energy in the manufacturing sector in the future, energy diagnosis and management through EMS (Energy management system) and FEMS (Factory energy management system) are more necessary. In addition, restructuring into a low-energy consumption industry seems more necessary.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.326-330
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• 2005

Crahworthy design of trains is now indispensable procedure in modern railway vehicle design for ensuring the safety of passengers and crew. It is now widely recognized that a more strategic approach is needed in order to absorb higher level energy in a controlled manner and minimize passenger injuries effectively. The first design step in this strategic approach is the design of the front end structure(so called HE extremities) to absorb a large part of total impact energy and then the structure of passengers non-accommodation zones(so called HE extremities) is designed to absorb the rest of impact energy. In this paper, the passengers entrance door area is selected as the LE(low energy) extremities and the design of the LEE was carried out. The main part of LEE design procedures is the design of energy absorbing tubes. For this purpose, the several tube candidates are introduced and compared to each others with numerical crash simulation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.227-230
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• 2011

In this paper, we are proposed ECOPS(Energy Conserving optimal Path Schedule) algorithm that according to ALPS(Ad hoc network Localized Positioning System) algorithm the location information is received and the new head node is selected considering the energy efficiency. The proposed algorithm follows RODMRP(Resilient Ontology-based Dynamic Multicast Routing Protocol) structure, that is the hierarchic cluster structure. And by using the location information of the node, it maintains the cluster which the energy is efficient with the production. It increases the life time of the total routing structure.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.1
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• pp.20-30
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• 2023

In this paper, the Energy Flow Finite Element Analysis (EFFEA) was performed to predict the acoustic and vibrational responses of complicated plate structures considering improved Fluid-Structure Interaction (FSI). For this, a new power transfer relationship was derived at the area junction where two different fluids are in contact on both sides of the plate. In order to increase the reliability of EFFEA of complicated plate structures immersed in a high-density fluid, the corrected flexural wavenumber and group velocity considering fluid-loading effect were derived. As the specific acoustic impedance of the fluid in contact with the plate increases, the flexural wavenumber of the plate increases. As a result, the flexural group velocity is reduced, and the spatial damping effect of the flexural energy density is increased. Additionally, for the EFFEA of arbitary-shaped built-up structures, the energy flow finite element formulation for the acoustic tetrahedral element was newly performed. Finally, for validation of the derived theory and developed software, numerical applications of complicated plate structures submerged in seawater or air were successfully performed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.4
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• pp.385-390
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• 2023

In this paper, the 1,700 V level SiC-based power MOSFET device widely used in electric vehicles and new energy industries was designed, that is, a single trench gate power MOSFET structure and a double trench gate power MOSFET structure were proposed to analyze electrical characteristics while changing the design and process parameters. As a result of comparing and analyzing the two structures, it can be seen that the double trench gate structure shows quite excellent characteristics according to the concentration of the drift layer, and the breakdown voltage characteristics according to the depth of the drift layer also show excellent characteristics of 200 V or more. Among them, the trench gate power MOSFET device can be applied not only to the 1,700 V class but also to a voltage range above it, and it is believed that it can replace all Si devices currently applied to electric vehicles and new energy industries.

• Ocean Systems Engineering
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• v.14 no.2
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• pp.157-169
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• 2024

The sudden release of water from a dam failure can trigger bores on a flat surface and exert substantial impact forces on structures. This flow poses a high-risk flood hazard to downstream urban areas, making it imperative to study its impact on structures and devise effective energy dissipators to mitigate its force. In this study, a combination of Genetic Algorithm optimization and numerical modeling is employed to identify the optimal energy dissipator. The analysis reveals that a round arc-shaped structure proves most effective, followed by a triangular shape. These shapes offer wide adaptability in terms of structure dimensions. Structures with higher elevation, especially those with round or triangular shapes, demonstrate superior energy dissipation capabilities. Conversely, square-shaped structures necessitate minimal height to minimize impact forces. The optimal width for dissipating energy is found to be 0.9 meters, allowing for effective wave run-up and propagation. Furthermore, the force exerted on structures increases with higher initial water levels, but diminishes with distance from the dam, highlighting the importance of placement in mitigating impact forces.