• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.90-91
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• 2003

대부분의 가공기 혹은 측정기에 있어 이송테이블은 그 기능수행의 기본을 담당하고 있으며 이송테이블의 운동 정밀도와 고속화는 목표하는 정밀도와 생산성으로 직결된다. 종래에는 형상특성, 열변형 등의 계통 오차만을 오프라인(Off-line)으로 측정하고 소프트웨어적으로 보상하는 방법을 사용하였으나 초정밀 분야에서 요구되는 테이블의 운동정밀도는 기계적 강성한계를 넘는 정밀도이므로, 테이블 이송 시 발생하는 운동오차를 실시간으로 측정하고, 보상할 수 있는 온라인(On-line)개념의 능동형 보상이 필요하다. (중략)

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.5
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• pp.933-939
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• 2007

There is a tremendous increase in the growth of Internet making people's life easy. The rapid growth in technology has caused misuse of the Internet like cyber Crime. There are several vulnerabilities in current firewall and Intrusion Detection Systems (IDS) of the Network Computing resources. Automatic real time station chase techniques can track the internet invader and reduce the probability of hacking Due to the recent trends the station chase technique has become inevitable. In this paper, we design and implement Active Security system using ICMP Traceback message. In this design no need to modify the router structure and we can deploy this technique in larger network. Our Implementation shows that ICMP Traceback system is safe to deploy and protect data in Internet from hackers and others.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.4
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• pp.341-347
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• 2001

Harmonics and fundamental reactive current of nonlinear loads in serious unbalanced power condition, are compensated by current synchronous detection(CSD) theory which is also acceptable for single phase power system. But, the CSD theory is not suitable any more, in case of controlled independently harmonics and reactive component. Therefore, a new algorithm, the expanded current synchronous detection(ECSD) theory for a three phase active power filter based on decomposition of fundamental reactive, distorted components, is proposed in this paper. The proposed ECSD theory is experimented and tested comparison with a few power theories under asymmetrical condition in power system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1467-1474
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• 2010

A tile type active T/R(Transmit/Receive) module for X-band active array radar is demonstrated in this paper. Proposed tile type structure based on fuzz button solderless vertical interconnection shows wide band characteristic of about 30 % bandwidth in X-band with insertion loss of below 0.6 dB and input and output VSWR of less than 1.7. Moreover, the mismatching generally appeared in the vertical interconnection which shown wide band characteristic can also be minimized and, therefore, good gain flatness can be achieved.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.203-208
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• 2014

In this paper, the antenna of a small active RFID for 433MHz is proposed, and the proposed antenna is a kind of built-in antenna, which uses IFA structure. The performance was improved by the change of the spacing between the feed point and short strip, inserting the meander line structure in a radiator, and varying the gap between the radiator and the ground plane in the proposed antenna. To confirm the characteristics of the antenna parameters, HFSS from ANSYS Inc. was used for the analysis. The frequency band of 433MHz Active RFID is from 433.67 to 434.17 MHz. There is a value of return loss less than -9.54 dB in 433MHz band of the active RFID, and the maximum antenna gain is -4.28dBi. The Jig size of the proposed antenna is $72{\times}44{\times}1mm$, and the size of the antenna area is $35.5{\times}19.5mm$. The result proved the possibility of the practical use on miniaturized 433MHz antenna using IFA structure that came from comparing and analyzing the measured and simulated data of the antenna.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.12
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• pp.1128-1138
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• 2010

One of the typical problems in the precise vibration is resonance characteristics at low frequency disturbance due to a heavy mass. An electro-magnetic(EM) air spring is a kind of vibration control unit and active isolator. The EM air spring in this study aims at removing the low frequency resonance for semiconductor manufacturing. The mechanical and electronic parts in the active isolator are designed to operate under a weight of 2.5 tons. The EM spring is floated using air pressure in a pneumatic elastic chamber and actuated by EM levitation force. The actuator consists of a EM coil and a permanent magnetic plate which are installed inside of the chamber. An air mount was constructed for the experiment with a stone surface plate, 4 active air springs, 4 gap sensors, a DSP controller, and a multi-channel power amp. A PD control method and operating logic was applied to the DSP. Simulation using 1/4 model was carried out and compared with the experiments. The time duration and maximum peak at resonance frequency can be reduced sharply by the proposed system. The results show that the active system can avoid the resonance caused by the natural frequency of the passive system.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.6
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• pp.102-109
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• 1998

As the fundamental study of an active suspension system, computer simulation is performed using a quarter model. Design data for the development of active suspension system are presented through performance estimation of active control laws in the time and frequency domain. The verification of compromise between ride quality and handling characteristics is carried out.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.227-231
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• 1992

본 연구에서는 ER(electro-rheological) 유체을 이용한 가변댐퍼(variable damper)를 제안했다. 전기장(electric field) 부하시 Bingham특성을 갖는 ER유체는 전기장에따라 항복전단응력이 변하기 때문에이를 이용하여 댐핑력을 제어할 수 있다. 피스톤의 상하압력차가 전기장의 함수이기 때문에 기존의 비능동 혹은 능동형 댐퍼에서 필요로하는 복잡한 밸브시스템이 필요없으며, 따라서 구조면에서 매우 간단하게 설계될 수 있고, 반응시간 또한 매우 빠르다. 간단한 현가정치 모델을 설정 하여제안된 ER 댐퍼의 효율성과 우수성을 주파수 및 시간 영역에서 해석하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.120-121
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• 2011

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.10a
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• pp.291-293
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• 2012

AMD 능동형 제진장치를 이용하여 플로팅 구조물을 제어하기 위해서는 수조실험을 통해 플로팅 함체 구조물의 롤링방향에 대한 동적 특성을 추정한 후 대상 구조물 특성에 적합한 제어알고리즘을 적용하여 수치시뮬레이션을 통한 제어의 가능성 확인 및 향후 실제 제진장치를 설치하여 검증실험을 통해 플로팅 구조물 능동제어의 효과를 검증해야 한다.