• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.152-155
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• 2005

A method of three-dimensional curved surface generation was studied for multi-point dieless forming (MPDF) in the shipbuilding industry. Three-dimensional coordinates of punch elements were obtained from objective surfaces using a proprietary CAD program. MPDF surfaces were generated by adjusting the height of punch elements in accordance with the coordinates. Some problems, such as collision of punch elements and contact between plates and punch bodies, were anticipated from the analysis of the results. A twisted surface was formed successfully by MPDF in a laboratory scale, which suggests possibility of application of the technology to the shipbuilding industry.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.1963-1965
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• 1998

In this paper, a new simplified configuration for a multi-level PWM inverter is proposed. The proposed inverter consists of an auxiliary circuit with one switching device, and 3 phase full-bridge inverter. The proposed inverter, in spite of reduction of the switching devices, offers characteristics similar to the NPC(Neutral - point - clamped)- PWM inverter. Also, since the reduction of the switching devices, the control strategy is simplified. And switching loss is reduced. In addition to, it is possible that reliable DC level voltage than former multi-level inverter. And load power application is same to conventional NPC-PWM inverter. The performance of the system is verified by simulation. In this paper, show the simulation result of the single phase full bridge inverter application.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.1130-1132
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• 1997

This paper proposed an application of artificial neural networks to security assessment(SA) in power system. The SA is a important factor in power system operation, but conventional techniques have not achieved the desired speed and accuracy. Since the SA problem involves classification, pattern recognition, prediction, and fast solution, it is well suited for Kohonen neural network application. Self organizing feature map(SOFM) algorithm in this paper provides two dimensional multi maps. The evaluation of this map reveals the significant security features in power system. Multi maps of multi prototype states are proposed for enhancing the versatility of SOFM neural network to various operating state.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.311-319
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• 2008

We present an innovative method of multi physics application involving energetic materials. Energetic materials are related to reacting flows in extreme environments such as fires and explosions. They typically involve high pressure, high temperature, strong shock waves and high strain rate deformation of metals. We use an Eulerian methodology to address these problems. Our approach is naturally free from large deformation of materials that make it suitable for high strain rate multi-material interacting problems. Furthermore we eliminate the possible interface smearing by using the level sets. We heave devised a new level set based tracking framework that can elegantly handle large gradients typically found in reacting gases and metals. We show several work-in-progress application of our integrated framework.

• Electronics and Telecommunications Trends
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• v.37 no.4
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• pp.46-59
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• 2022

The 5G MEC (Multi-access Edge Computing) technology offers network and computing functionalities that allow application services to improve in terms of network delay, bandwidth, and security, by locating the application servers closer to the users at the edge nodes within the 5G network. To offer its interoperability within various networks and user equipment, standardization of the 5G MEC technology has been advanced in ETSI, 3GPP, and ITU-T, primarily for the MEC platform, transport support, and MEC federation. This article offers a brief review of the standardization activities for 5G MEC technology and the details about the system architecture and functionalities developed accordingly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.4
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• pp.319-324
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• 2002

The Integration of agent technology and security technology is needed to many application areas like electronic commerce. This paper suggests a model of extended multi-agent engine which supports privacy, integrity, authentication and non-repudiation on agent communication. Each agent which is developed with the agent engine is composed of agent engine layer and agent application layer. We describe and use the concepts self-to-self messages, secure communication channel, and distinction of KQML messages in agent application layer and messages in agent engine layer. The suggested agent engine provides an agent communication language which is extended to enable secure communication between agents without any modifications or restrictions to content layer and message layer of KQML. Also, in the model of our multi-agent engine, secure communication is expressed and processed transparently on the agent communication language.

• Architectural research
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• v.14 no.3
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• pp.99-108
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• 2012

An innovative multi-story Semi-Active Tuned Mass Damper (SATMD) building system is proposed to control seismic response of existing structures. The application of adding new stories as large tuned mass and semi-active (SA) resettable actuators as central features of the control scheme is derived. For the effective control of the structures, the optimal tuning parameters are considered for the large mass ratio, for which a previously proposed equation is used and the practical optimal stiffness is allocated to the actuator stiffness and rubber bearing stiffness. A two-degree-of freedom (2-DOF) model is adopted to verify the principal efficiency of the suggested structural control concept. The simulations for this study utilizes the three ground motions, from SAC project, having probability of exceedance of 50% in 50 years, 10% in 50 years, and 2% in 50 years for the Los Angeles region. 12-story moment resisting frames, which are modified as '12+2' and '12+4' story structures, are investigated to assess the viability and effectiveness of the system that aims to reduce the response of the buildings to earthquakes. The control ability of the SATMD scheme is compared to that of an uncontrolled and an ideal Passive Tuned Mass Damper (PTMD) building system. From the performance results of suggested '12+2' and '12+4' story retrofitting case studies, SATMD systems shows significant promise for application of structural control where extra stories might be added.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.946-951
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• 2009

The research aims to study a new, optimum and renewable energy application method that can cover the minimum energy and operation costs within a range of school budgets. By deriving the optimum application method, it is expected to maximize the cooling/heating and water heating energy saving efficiencies for educational facilities. Therefore, this research carried out a study on the new/renewable energy utilization technique diffusion expansion method and the optimum method. As a result, the first optimum plan was introduced with the multi-type geothermal heat pump 174kW + solar heat collector $94\;m^2$ + highly efficient electronic cooling/heating device (EHP) 249.4kW. On the other hand, the second optimum plan was induced as the multi-type geothermal heat pump 255.2kW + highly efficient electronic cooling/heating device (EHP) 168.2kW.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.10
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• pp.564-574
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• 2009

The study is conducted to study a new, optimum and new and renewable energy application method that can cover the minimum energy and operation costs within a range of school budgets. By deriving the optimum application method, it is expected to maximize the cooling/heating and hot water supply energy saving efficiencies for educational facilities. Therefore, this research implemented a study on the new and renewable energy utilization technique diffusion expansion method and the optimum method. As a result, the first optimum plan was introduced with the multi-type geothermal heat pump 475.6 kW+highly efficient electronic cooling/heating device(EHP) 545.2 kW. On the other hand, the second optimum plan was induced as the multi-type geothermal heat pump 261kW+solar heat collector $240\;m^2$+highly efficient electronic cooling/heating device(EHP) 759.8 kW.

• The Journal of Korean Medicine
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• v.32 no.4
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• pp.68-74
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• 2011

Objective: The purpose of this study is to expatiate on high performance thin layer chromatography (HPTLC) as a simple, easy and scientific method for evaluation and standardization of herbal formulae. Methods: Through retrieving HPTLC application for herbal formulae in the literatures, the current situation of HPTLC application, and potential as well as limitation of HPTLC as a standardization method for multi-herbal drug was studied. Results: HPTLC is a speedy, inexpensive and well-operable tool for possessing multi-capability on component identification, separation, quantification and purification compared to other methods, such as high performance liquid chromatography (HPLC), gas chromatography (GC). Conclusions: HPTLC is considered as an available and convenient method for quality control and standardization of multi-herbal drugs. Thereby, this method could be recommended to widely applicate in the traditional Korean medicine.