• Title/Summary/Keyword: high speed mode

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The Authentication Structure Based Mobile PKI (모바일 PKI 기반한 인증 구조)

  • 김미혜;서세영
    • The Journal of the Korea Contents Association
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    • v.4 no.1
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    • pp.67-75
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    • 2004
  • In this paper, we design an authentication model based mobile PKI (Public Key Infrastructure). The authentication mood consists of Root-CA Home-network agent and Foreign-network agent. CA will going to gave the delegation ticket to Home-Agent or Foreign-Agent when they request. The authentication mode information security is various characteristic more then high speed, mobile network and low cost more then previous structure of assure information security.

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Discussions on the Combustion Dynamics of RDE with Relevance to the Liquid Rocket Combustion Instability (RDE의 연소동역학 및 액체 로켓 연소 불안정과 연관성에 대한 고찰)

  • Choi, Jeong-Yeol
    • 한국연소학회:학술대회논문집
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    • 2012.11a
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    • pp.363-366
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    • 2012
  • Detonative combustion is considered as a promising combustion mechanism for improving thermodynamic efficiency of power generation systems as a PGC, as well as high-speed propulsion systems. Among the various types of detonative combustion, RDE is fascinated by many researchers because of the simplicity and continuos operation characteristics. Present paper is an introduction to the physical and operational concept of RDE with a brief history of RDE researches and recent development activities. Additional discussions will devoted to the relevance to the tangential mode instabilities in liquid rocket engines and improvement of liquid rocket performance.

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Design and Implementation of a Fast DIO(Digital I/O) System (고속 DIO(Digital I/O) 시스템의 설계와 제작)

  • Lee, Jong-Woon;Cho, Gyu-Sang
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.55 no.5
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    • pp.229-235
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    • 2006
  • High speed PC-based DIO(Digital I/O) system that consists of a master device and slave I/O devices is developed. The PCI interfaced master device controls all of serial communications, reducing the load on the CPU to a minimum. The slave device is connected from the master device and another slave device is connected to the slave device, it can repeated to maximum 64 slave devices. The slave device has 3 types I/O mode, such as 16 bits input-only, 16 bits output-only, and 8bits input-output. The master device has 2 rings which can take 64 slaves each. Therefore, total I/O points covered by the master is 2048 points. The slave features 3 types of input/output function interchangeability by DIP switch settings. Library, application, and device driver software for the DIO system that have a secure and a convenient functionality are developed.

The impact of TGV on the mobility (TGV의 개통효과 : 유동성 변화를 중심으로)

  • Lee Kyung-Chul
    • Proceedings of the KSR Conference
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    • 2004.06a
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    • pp.375-379
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    • 2004
  • The purpose of this study is to analyze the evolution of mobility after the commercial opening of french TGV through an examination on the precedent studies. The result of this study is as follows: Firstly, the TGV is competitive against the airplanes and automobiles within the 2 or 3 hours' service area, especially in the business trip markets. But in the recreational trips over this service area, 3 or 4 hours, the TGV remains as an important mode of transportation. Secondly, in a range within approximately 200 km, 1 hour by TGV, the french high speed train is not competitive against the automobiles by the lack of flexibility and commodity which are normally providing by the automobiles. This study shows the importance of permanent monitoring system on the KTX travellers' behavior to strengthen the market share of KTX.

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The reduction of spatter in $CO_2$ inverter Arc Weling machine by the current control at the moment of short (단락순간의 전류제어에 의한 $CO_2$ 인버터 아크 용접기의 스패터 저감)

  • 고재석;채영민;이승요;목형수;최규하
    • Proceedings of the KIPE Conference
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    • 1999.07a
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    • pp.585-590
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    • 1999
  • The conventional $CO_2$ inverter arc machine has constant voltage output characteristic and uses constant wire speed controller for welding current control. By adoption of PWM inverter to the welding machine, the spattering was reduced rather than the thyrister arc welding machine or AC arc welding machine. Moreover, by the high switching frequency, the output reactor size could be reduced evidently. Recently, the studies on optimal voltage and current waveform for the welding performance improvement have been studied. In this paper, a new instantaneous output current control scheme during the short circuit mode was proposed and showed the capability of arc stability improvement and the reduction of spatter generation.

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An Experimental Study on the Characteristic of Sprays and Spray Flames by Twin-Fluid Atomizer (2유체 분사노즐을 이용한 분무 및 연소특성에 관한 실험적 연구)

  • 백민수;오상헌
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.2
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    • pp.548-558
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    • 1995
  • An experimental investigation has been conducted to study the spray and combustion characteristics using the air-assisted twin fluid atomizer. Axial mean and fluctuating velocity components as well as drop-size distributions in non-reaction spray were measured with a nonintrusive phase doppler technique. Droplet number density distributions were also visualized using high speed CCD camera. Locations of spray and flame boundaries are obtained by direct photographic method. It is confirmed that at the fixed fuel flow rate, the increase of the atomizing air flow causes improvements on both spray and combustion characteristics under stable flame conditions. Internal group combustion modes where flame is located inside the spray boundary are observed to exist in the upstream region of higher droplet number density.

Aerodynamic Design of SUAV Flaperon (스마트무인기 플래퍼론 공력설계)

  • Choi Seong-Wook;Kim Jai-Moo
    • 한국전산유체공학회:학술대회논문집
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    • 2004.10a
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    • pp.165-171
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    • 2004
  • Smart UAV, which adopting tiltrotor aircraft concept, requires long endurance and high speed capability simultaneously These two contradictable flight performances are hard to meet with single wing concept and inevitably require the operation of flap system which should reveal optimal performance for each flight mode. In order to design SUAV flaperon satisfying the performance requirement, various configurations are generated and their aerodynamic performances are analyzed using numerical flow computations around flaps. Considering aerodynamic performance and manufacturing simplicity, a final flap configuration is selected.

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Hydrodynamic characteristics of a pendant dmp by acoustic wave (음파가 가해진 액적의 진동에 관한 동적 특성)

  • Moon Jong Hoon;Kim Ho-Young;Kang Byung Ha
    • 한국가시화정보학회:학술대회논문집
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    • 2004.11a
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    • pp.76-79
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    • 2004
  • Dynamic oscillation motion of a pendant drop has been Investigated experimentally when acoustic wave is applied. This problem is of particular interest in the understanding of transport phenomena, accompanied by liquid drop. In this experiment, pendant drop was made to oscillate by inducing the acoustic wave and the subsequent drop motion was recorded by a high-speed camera. The results obtained indicate that liquid drop hanging on the flat surface has resonant frequencies on each shape oscillation modes. It is also found that exists the swing mode of oscillation on the pendant drop.

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Damage localization in plate-like structure using built-in PZT sensor network

  • Liu, Xinglong;Zhou, Chengxu;Jiang, Zhongwei
    • Smart Structures and Systems
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    • v.9 no.1
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    • pp.21-33
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    • 2012
  • In this study, a Lamb-wave based damage detection approach is proposed for damage localization in plate. A sensor network consisting of three PZT wafer type actuators/sensors is used to generate and detect Lamb waves. To minimize the complication resulted from the multimode and dispersive characteristics of Lamb waves, the fundamental symmetric Lamb mode, $S_0$ is selectively generated through designing the excitation frequency of the narrowband input signal. A damage localization algorithm based upon the configuration of the PZT sensor network is developed. Time-frequency analysis method is applied to purify the raw signal and extract damage features. Experimental result obtained from aluminum plate verified the proposed damage localization approach.

Tensile Failure Characterization of Composites for Railway Vehicle (철도차량 복합소재의 인장파괴 특성분석)

  • Kim, Jeong-Guk;Kwon, Sung-Tae;Kim, Jung-Seok;Yoon, Hyuk-Jin
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.1231-1235
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    • 2010
  • The tensile failure behavior of polymer matrix composite materials was investigated with the aid of a nondestructive evaluation (NDE) technique. The materials, E-glass fiber reinforced epoxy matrix composites, which are applicable to carbody materials in railway vehicles to reduce weight, were used for this investigation. In order to explain stress-strain behavior of polymer matrix composite sample, the infrared thermography technique was employed. A high-speed infrared (IR) camera was used for in-situ monitoring of progressive damages of polymer matrix composite samples during tensile testing. In this investigation, the IR thermography technique was used to facilitate a better understanding of damage evolution, fracture mechanism, and failure mode of polymer matrix composite materials during monotonic loadings.

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