• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.8 s.113
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• pp.848-856
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• 2006

This paper describes the aeroelastic stability test of the small-scaled 'Next-generation Blade(NRSB)' with NRSH (next-generation hub system) and HCTH hingeless hub system in hover and forward flight conditions. Excitation tests of rotor system installed in GSRTS (general small-scale rotor test system) at KARI (Korea Aerospace Research Institute) were carried out to get lead-lag damping ratio of blades with flexures as hub flexure. MBA(moving block analysis) technique was used for the estimation of lead-lag damping ratio. First, NRSB-1F blades with HCTH hub system, then NRSB- 1F with NRSH hub system were tested. Second, NRSB-2F blades with NRSH hub system were tested. Tests were done on the ground and in the wind tunnel according to the test conditions of hover and forward flight, respectively. Non-rotating natural frequencies, non-rotating damping ratios and rotating natural frequencies were showed similar level for each cases. Estimated damping ratios of NRSB-1F, NRSB-2F with HCTH and NRSH were above 0.5%, and damping ratio increased by collective pitch angle increasement. Furthermore damping ratios of NRSB-2F were higher than damping ratios of NRSB-1F in high Pitch angle. It was confirmed that the blade design for noise reduction would give observable improvement in aeroelastic stability compared to paddle blade and NRSB-1F design.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.948-949
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• 2008

In this paper, an effect on power conversion unit in next generation high-speed train by loss of contact between a contact wire and pantograph supplied electrical power to high-speed train are investigated. One of the most important needs accompanied by increasing the speed of high-speed train is reduced that arc phenomenon by loss of contact brings out EMI. To analysis of conducted EMI source on powering mode of next generation high-speed train, it is necessary electrical modeling system between the contact wire and the pantograph according with loss of contact. Therefore analytical model of a contact wire and a pantograph is constructed to simulate the behaviour of loss of contact. The reliability of the modeling system is verified by simulation implementation on loss of contact.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.178-180
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• 2003

This paper proposes a real-time simulator that can simulate dynamic changes of a substation for intelligent SCADA system. The simulator consists of RTDS, voltage and current amplifier, IED, and RTU. The simulator is verified by system implementation and event simulation of a substation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.11
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• pp.1478-1481
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• 2019

As core technologies(IoT, 5G, Cloud, Bigdata, AI etc) leading the Fourth Industrial Revolution promote smart convergence across the national socio-economic infrastructure, the threat of new forms of cyber attacks is increasing and the possibility of massive damage is also increasing. Reflecting this trend, cyber security is expanding from simple information protection to CPS(Cyber Physical System) protection that combines safety and security that implements hyper-connectivity and ultra-reliability. This study introduces the recent evolution of cyber attacks and looks at the next generation cyber security technologies based on the conceptual changes of cyber security technologies such as SOAR(Security Orchestration, Automation and Response) and Zero Trust.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.4
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• pp.22-31
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• 2002

A high-speed rail system represents a typical example of large-scale multi-disciplinary systems, consisting of subsystems such as train, electrical hardware, electronics, control, information, communication, civil technology etc. The system design and acquisition data of the large-scale system must be the subject under strict configuration control and management. Not only the requirements of the large-scale system dictate the contracts with the suppliers but also become the basis for the development process, project execution, system integration, and testing. The requirements database provide the system design specification of all development activities. Using the RDD-100, a systems engineering tool, the Korea next-generation high-speed rail program can establish requirements traceability and development process management in performing the enabling train technology development projects. This paper presents the results from a computer-aided systems engineering application to the Korea next-generation high-speed railway project. Especially, the focus of the study was on requirement management and PBS(Product Breakdown Structure) management.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.3
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• pp.439-444
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• 2011

In this paper, we implemented the intelligent smart monitor system for next generation which is most commonly viewed information in a vehicle from the instrument cluster, where speed, tachometer, fuel, engine temperature, fuel gauge, turn indicators and warning lights and provide the driver with an array of informations. Designed Smart HUD(Head-Up-Display) monitor system is composed TFT LCD, LCD Back light led, plane mirror, lens and controllers parts and it was assembled to intelligent integrated smart monitor system. Finally, we analyze intelligent integrated smart monitor system for driver safety vehicles and present the possibility to apply to smart intelligent HUD total monitor system for next generation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.325-329
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• 2003

Nowadays many peoples are using helicopter in various fields, not only military use but also common people applications such as air-measurement, photography, transportation of goods and persons, saving life and fire fighting etc. And it will be expected more popular than now. Most important part of helicopter to increasing performance and to reducing noise is rotor hub-system. Hub system consists of rotor-blade and rotor-hub. We participate to develop next-generation rotor hub system with elastomeric bearing, part of rotor hub. In this paper we introduce about the role and shape of elastomeric bearing in next-generation helicopter hub system. Then we study about bearing-material requirements and measuring methods. Finally we represent some experimental results.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.115-125
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• 2005

This paper discusses how to effectively design a next-generation wireless communication system that can possibly provide very high data-rate transmissions and versatile quality services. In order to accommodate the sophisticated user requirements and diversified user environments of the next-generation systems, it should be designed to take an efficient and flexible structure for multiple access and resource allocation. In addition, the design should be optimized for cost-effective usage of resources and for efficient operation in a multi-cell environment. As orthogonal frequency division multiple access (OFDMA) has turned out in recent researches to be one of the most promising multiple access techniques that can possibly meet all those requirements through efficient radio spectrum utilization, we take OFDMA as the basic framework in the next-generation wireless communications system design. So, in this paper, we focus on introducing an OFDMA-based downlink system design that employs the techniques of hybrid multiple access (HMA) and frequency group (FG) in conjunction with intra-frequency group averaging (IFGA). The HMA technique combines various multiple access schemes on the basis of OFDMA system, adopting the multiple access scheme that best fits to the given user condition in terms of mobility, service, and environment. The FG concept and IFGA technique help to reduce the feedback overhead of OFDMA system and the other-cell interference (OCI) problem by grouping the sub-carriers based on coherence band-widths and by harmonizing the channel condition and OCI of the grouped sub-carriers.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2194-2195
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• 2011

The propulsion system of next generation electric vehicle is different from the structure and control methods compared with conventional induction motor vehicles by applying an interior permanent magnetic synchronous motor. Permanent magnet motor should be controlled by each individual motor, propulsion device have 1C1M structure by a single inverter to control a single motor.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2002.11a
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• pp.466-472
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• 2002

본 논문에서는 인터넷과 데이터 통신의 급격한 증가에 의해 다양화하는 패킷망과 기존의 공중전화망, 가입자망 등을 단일망으로 통합하여 관리할 수 있는 소프트스위치 시스템을 표준 컴퓨팅 플랫폼으로 개발하는 방안을 제시하였다. 본 논문에서 제시하는 소형 소프트스위치는 기본적인 라우팅, 서비스제어, 호 제어, 미디어 제어가 가능하도록 설계하였으며 사용자가 원하는 기능을 스스로 선택할 수 있는 프로그래머블 콜 프로세싱이 가능하도록 구현하였다.