• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.519-522
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• 2002

An active phased array antenna consists of many channels. Each channel has a different initial phase shift and gain because of the inequality in the active circuits themselves, interface between radiators and active circuits, and beam-forming circuits and other antenna system configurations. This raises an inherent problem in active phased array antennas. To compensate for this problem the initial phase and gain of each channel should be calibrated. This paper presents an efficient calibration method for an initial phase variation of each channel in active phased array antennas. We tested our method in an active phased array antenna, and obtained good results in the radiation pattern and beam direction of antenna.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.10
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• pp.1051-1059
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• 2013

In general, lateral ride comfort of railway vehicle is mainly influenced by a secondary suspension placed between the bogie and carbody. Higher operating speeds of train results in increased vibration of carbody, which has a negative impact related to the ride comfort. To solve this problem, researches to replace the conventional passive suspension with (semi)active technology in the secondary suspension of a railway vehicle have been carried out. The semi-active suspension using the magneto-rheological damper is relatively simpler system and has advantage in maintenance compared to the hydraulic type semi-active damper. This study was performed to reduce lateral vibration acceleration of carbody related to ride comfort of railway vehicles with a semi-active suspension system. The numerical analysis was conducted by replacing passive lateral damper with semi-active MR damper, and robust control with the MR damper was applied to the 1/5 scaled railway vehicle model.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.271-273
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• 1995

Hybrid active filters utilize passive filters to reduce the voltage rating and hence the VA rating of the active filter converter. A novel hybrid active filter topoloty to minimize utility current harmonics at high power levels is presented in this paper. The proposed topology combines both passive and active filters to obtain the lowest converter VA rating as compared to the converter rating in the active filter and the series-active hybrid filter configurations. This is demonstrated with experimental results from a laboratory model. Simulation results showing the effect of passive filter impedance are presented.

• Journal of Microbiology and Biotechnology
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• v.24 no.5
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• pp.719-723
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• 2014

Caspases are a family of cysteine proteases that play an important role in the apoptotic pathway. Caspase-6 is an apoptosis effector that cleaves a variety of cellular substrates. The active form of the enzyme is required for use in research. However, it has been difficult to obtain sufficient quantities of active caspase-6 from Escherichia coli. In the present study, we constructed a caspase-6 with a 23-amino-acid deletion in the pro-domain. This engineered enzyme was expressed as a soluble protein in E. coli and was purified using affinity resin. In vitro enzyme assay and cleavage analysis revealed that the engineered active caspase-6 protein had characteristics similar to those of wild-type caspase-6. This novel method can be a valuable tool for obtaining active caspase-6 that can be used for screening caspase-6-specific substrates, which in turn can be used to elucidate the function of caspase-6 in apoptosis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.295-298
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• 1995

We performed a research to improve the performance of active bar model which is used in tracking algorithm. Active bar model is a simplified model of snake model. If we used the sctive bar model, the numerical procedure for real time tracking problem can be carried out faster than snake model. However the demerit of active bar algorithms is that we can't used the provious image data because each time it has to reconstruct the active bar. In this paper we proposed advanced algorithm for active bar model. The proposed model can improve tracking abilities by preserving the active bar during the process and changing the energy functional.

• Archives of Pharmacal Research
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• v.10 no.4
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• pp.208-211
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• 1987

Sedative activity of Zizyphi fructus was evaluated by potentiation of hexobarbital-induced hypnosis test and its active principles have been characterized as nornuciferine and lysicamine. A new cyclopeptide alkaloid, daechucyclopeptide-1 was isolated together with zizyphusine.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.793-798
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• 2014

To generate finite-power Airy beams, a novel holographic method is proposed. We record the interference pattern between an Airy beam (signal beam) and plane wave (reference beam) on a photopolymer, then decode the hologram by illuminating with the reference beam. The reconstructed beams still present the non-diffraction, acceleration, and self-healing features of optical Airy beams. In addition, angular multiplexing of two Airy beams with opposite acceleration directions is presented.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.2
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• pp.162-168
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• 2014

Use of nonlinear loads, such as power converters, fluorescent lamps and adjustable speed motor drives, is expected to grow rapidly. All of these loads inject harmonic currents. This paper presents the active filtering of the harmonic distortion generated by the compact fluorescent lamps (CFL). The Instantaneous active and reactive power theory (the p-q Theory) is used to design the control of parallel active filter. The control scheme has been verified using Matlab/Simulink with SimPower Systems through a set of simulation tests under different load conditions. Also, the tuning of the active power filter is performed to improve the quality of the electrical power supply.

• ETRI Journal
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• v.39 no.6
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• pp.859-865
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• 2017

This paper presents a method for determining the optimum active-area width (OAW) of solar cells in a module architecture. The current density-voltage curve of a reference cell with a narrow active-area width is used to reproduce the current density profile in the test cell whose active area width is to be optimized. We obtained self-consistent current density and electric potential profiles from iterative calculations of both properties, considering the distributed resistance of the contact layers. Further, we determined the OAW that yields the maximum efficiency by calculating efficiency as a function of the active-area width. The proposed method can be applied to the design of the active area of a dye-sensitized solar cell in Z-type series connection modules for indoor and building-integrated photovoltaic systems. Our calculations predicted that OAW increases as the sheet resistances of the contact layers and the intensity of light decrease.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.10b
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• pp.1427-1430
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• 2001

액티브 네트워크는 기존의 패킷 교환 네트워크와 달리 네트워크 중간 노드에서 사용자의 요구나 서비스 특성에 따라 패킷을 처리할 수 있는 차세대 네트워크 구조이다. 기존의 네트워크 문제점을 개선하고 네트워크에 지능을 부여한다는 측면에서 새로운 접근 방식이지만 아직 해결해야 할 많은 논지를 가지고 있다. 본 논문은 액티브 네트워크와 기존의 네트워크 공존문제를 해결, 관리하기 위한 SNMP 확장에 관한 모델을 제시하고, SNMP 기반의 네트워크와 비교 분석하기로 한다.