• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.574-578
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• 2017

In order to achieve iterative design in early R&D period, a Distributed and Real-time Integrated Simulation System for avionics based on a Model-Based Systems Engineering (MBSE) method is proposed. The proposed simulation system includes driver, simulation model, monitor, flight visual model and aircraft external model.The effect of this simulation system in iterative design and system verification is testified by several use cases. The result shows that the simulation system, which can play an important role in iterative design and system verification, can reduce project costs and shorten the entire R&D period.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.08a
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• pp.194-199
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• 2004

The paper does researches and analysis on the process of marine oil spill crisis response (MOSCR), and develops the marine oil spill crisis response simulation exercise system. The system developed by this paper is composed of four subsystems, including the training system of MOSCR, the geographical information system of MOSCR, the marine oil spill control and cleanup decision-making expert system, and the computer simulation exercise system. The paper builds up the applied model system of MOSCR. The system takes the marine oil spill crisis response geographical information system as the platform, which integrates all aspects of MOSCR. This system can offer an oil spill scene to the trainees and simulate the whole process of MOSCR on the interface of GIS.

• Journal of Power System Engineering
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• v.21 no.5
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• pp.35-40
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• 2017

The effects of the different rib geometries such as V-shaped continuous (case A), parallel broken (case B), and V-shaped broken (case C) ribs on the heat transfer and pressure drops in a divergent channel with $45^{\circ}$ inclined ribs on one wall or two walls are checked out. The top and bottom walls are adiabatic; two side walls are uniformly heated in the divergent rectangular channel. The tested Reynolds numbers are ranged from 22,000 to 75,000. The channel with two opposite walls inclined only has the length of test section of 1 m and the channel divergence ratio of $D_{ho}/D_{hi}=1.49$, corresponding to $1.43^{\circ}$ inclined walls. The results show in the identical pumping power that the V-shaped continuous rib (case A) with two ribbed walls is the greatest, but the parallel broken rib (case B) with one ribbed wall is the worst in the thermal performance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.203-206
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• 2003

The propellant feed system for small LRE of the thrust 250kgf designed and fabricated. Design on the propellant feed system is reflected with analysis of old system. Performance of the propellant feed system was proved by cold test and hot firing test. Consequencely, New feeding system found out more stable than old feeding system.

• Journal of Integrative Natural Science
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• v.9 no.1
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• pp.67-71
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• 2016

The university president direct election system in Korea had begun in 1987 as a movement of college democratization in the 1980s after 6.29 Declaration. Since then, many national/private universities had adopted the election system. However, it has posed many problems and it caused a sharp division of opinions between those who approve and disapprove the direct election system. Since 2005, the government has made official of the reformation and/or abolition of the university president direct election system, and has kept pushing for universities to give up the direct election system. Now, only 3 or 4 universities hold on to the system, and many universities have changed into the indirect election system. In the indirect election, a key is the composition of president nomination committee, which confirms the university members's variety. Many universities adopting the indirect election system have used simple random sampling, like drawing lots, to compose the president nomination committee. However, drawing lots has a problem that it has large possibility of composing a biased committee. This research suggests systematic sampling as an alternative to drawing lots. A numerical analysis was conducted using a data of a university in which the indirect election was implemented recently. The drawing lots gave the biased nomination committee. On the other hand, the systematic sample improves the problem and confirms more the variety of all members.

• International Journal of Railway
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• v.2 no.3
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• pp.113-117
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• 2009

Risk management is an important part of system assurance and it is widely used in safety-related system. Railway signal system is one kind of safety-related system and its most important goal is to guarantee the safety of railway system. The method based on risk management can find and solve the security issues of railway signal system more effectively. This paper introduces the basic conception of risk management, studies the whole process of risk management and related tools and techniques and discusses some key points qualitatively combining with the particularity of railway signal system.

• 한국초전도학회:학술대회논문집
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• v.16
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• pp.48-48
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• 2006

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.147-150
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• 1996

We are developing a teleconference system based on 3D medical image. The system consists in three sub-systems : conference operating system, medical image processing system and database management system. It makes it possible efficient computer-supported coorperative work among remote multi-located hospitals. In this paper, we present functions of each subsystem that have implemented until now.

• Structural Engineering and Mechanics
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• v.30 no.2
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• pp.191-209
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• 2008

A structural monitoring system based on cheap and wireless monitoring system is investigated in this paper. Due to low-cost and low power consumption, micro-electro-mechanical system (MEMS) is suitable for wireless monitoring and the use of MEMS and wireless communication can reduce system cost and simplify the installation for structural health monitoring. For system identification using wireless MEMS, a finite element (FE) model updating method through correlation with the initial analytical model of the structure to the measured one is used. The system identification using wireless MEMS is evaluated experimentally using a three storey frame model. Identification results are compared to ones using data measured from traditional accelerometers and results indicate that the system identification using wireless MEMS estimates system parameters with reasonable accuracy. Another smart sensor considered in this paper for structural health monitoring is Lead Zirconate Titanate (PZT) which is a type of piezoelectric material. PZT patches have been applied for the health monitoring of structures owing to their simultaneous sensing/actuating capability. In this paper, the system identification for building structures by using PZT patches functioning as sensor only is presented. The FE model updating method is applied with the experimental data obtained using PZT patches, and the results are compared to ones obtained using wireless MEMS system. Results indicate that sensing by PZT patches yields reliable system identification results even though limited information is available.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.6
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• pp.494-502
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• 2014

This paper presents a control method of the modular multilevel converter - high-voltage direct current (MMC-HVDC) system to regulate grid voltage on the basis of the Jeju Island power system. In this case, the MMC-HVDC system is controlled as a static synchronous compensator (Statcom) to exchange the reactive power with the power grid. The operation of the MMC-HVDC system is verified by using the PSCAD/EMTDC simulation program. The Jeju Island power system is first established on the basis of the parameters and measured data from the real Jeju Island power system. This power system consists of two line-commutated converter - high-voltage direct current (LCC-HVDC) systems, two Statcom systems, wind farms, thermal power plants, transformers, and transmission and distribution lines. The proposed control method is then applied by replacing one LCC-HVDC system with a MMC-HVDC system. Simulation results with and without using the MMC-HVDC system are compared to evaluate the effectiveness of the control method.