• Journal of electromagnetic engineering and science
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• v.5 no.3
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• pp.105-111
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• 2005

This paper presents the basic characteristics of a cutoff cavity-backed aperture antenna with a feed post and a parasitic post inserted parallel to the aperture. It is shown that this type of antenna forcibly resonates the cutoff cavity by adding a single external reactance to the parasitic post. The Galerkin's method of moments is used to analyze integral equations for the unknown electric current on each post and the aperture electric field on the aperture. The value of an external reactance for forced resonance is analytically obtained by deriving a determining equation. Also the current distribution on each post, aperture electric field distributions, and the radiation patterns are discussed. The theoretical analysis is verified by the measured return loss and radiation patterns.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.2
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• pp.142-148
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• 1990

This paper deals with the desing method of Superconducting AC Generator (SCG). The establishment of design principle and design procedure of SCG are included in this study. Electric characteristics of SCG, such as synchronous reactance and sub-sub-transient reactance, are specified first as constraints and the size of SCG is calculated. Synchronous reactance and sub-sub-transient reactance are important factors because they determine the steady state and transient characteristics of SCG, respectively. A 20KVA SCG with double-shielded single-rotor is chosen for the case study. The design procedure proposed in this papar will also be applicable to large scale generators.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.203-206
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• 2000

In this paper, we discuss an efficient steady-state analysis of reactance oscillators having multiple oscillations. Our oscillator is consisted of the Cauer or Foster reactance sub-circuit and a negative resistor such as tunnel diode. The reactance circuit has many resonance and antiresonance points on the frequency response curve. Such a circuit having the specified resonance and anti-resonance points can be easily synthesized with the fundamental circuit theory. In this case, the multiple oscillations may occur near at the anti-resonance points. We have developed a user friendly simulator for getting the exact steady state responses using the SPICE.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.1
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• pp.38-44
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• 2001

For double-circuit transmission line systems, an accurate digital distance relaying algorithm immune to the reactance effect is proposed. The apparent impedance calculated by the distance relay is influenced by the combined reactance effect of the fault resistance and the load current as well as the mutual coupling effect caused by the zero-sequence current of the adjacent parallel circuit. To compensate the magnitude and phase of the estimated impedance, this algorithm uses phase angle difference between the zero(positive) sequence of the both side of the system seperated by the fault point. The impedance measuring algorithm presented used a current distribution factor to compensate mutual coupling effect instead of the collected zero-sequence current of the adjacent parallel circuit.

• Electric Engineers Magazine
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• v.218 no.10
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• pp.25-32
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• 2000

유효전력, 리액티브 전력 및 피상전력은 역률 보정을 나타내기 위하여 보통 사용하는 전력 삼각형의 세가지 요소들이다. 킬로와트로 측정되는 유효전력은 유효한 일로 직접적으로 변환되는 전력이며 Volt-Amepere Reactance 또는 Kilo Volt Amp Reactance로 측정되는 무효전력은 모터와 같은 유도성 부하의 구동을 위해 필요한 전기자기장을 발생하기 위한 전기 에너지이다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.278-285
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• 2000

This paper presents the basic characteristics of the beam tilting dipole antenna element in which one reactance element is used for the impedance matching at the feed point. The radiation pattern is tilted by the properly determined driving point position, and the loading reactance is used to obtain forced resonance without great changes in tilt angle. The numerical results demonstrate that the reactance element should be loaded in the region where the driving point is placed to obtain forced resonance of the antenna with little changes in beam tilt angle. In case the proposed forced resonant beam tilting antenna with $0.8\lambda$ length is driven at $0.2\lambda$ from the center, the main beam tilt angle o.5 57.7 degrees, the highest power gain of 8.6 dB are obtained.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.3
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• pp.312-318
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• 2016

This paper presents a 2-6 GHz GaN HEMT power amplifier monolithic microwave integrated circuit (MMIC) with bridged-T all-pass filters and output-reactance-compensation shorted stubs using the $0.25{\mu}m$ GaN HEMT foundry process that is developed by WIN Semiconductors, Inc. The bridged-T filter is modified to mitigate the bandwidth degradation of impedance matching due to the inherent channel resistance of the transistor, and the shorted stub with a bypass capacitor minimizes the output reactance of the transistor to ease wideband load impedance matching for maximum output power. The fabricated power amplifier MMIC shows a flat linear gain of 20 dB or more, an average output power of 40.1 dBm and a power-added efficiency of 19-26 % in 2 to 6 GHz, which is very useful in applications such as communication jammers and electronic warfare systems.

• Asia pacific journal of information systems
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• v.17 no.1
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• pp.123-145
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• 2007

There are flourishing studies in the acceptance or usage of information systems literature. Most of them have taken the pro - acceptance view. Undesirably, information technologies often provoke users' reactance or resistance. This paper explores one of the negative reactions -psychological reactance. The present paper studies the effects of the users' perception of threatened freedom and personalization degree on intention to use recommendation services. High personalization can be a major motivation for users to accept recommendation systems. However recommendation services are a two-edged sword, which not only provides users the efficiency of decision making but also poses threats to free choice. When people consider that their freedom is reduced or threatened by others, they experience the motivational state to restore the freedom. This motivational state must be considered in understanding usage of information systems, especially personalized services which are designed for persuasion or compliance. This paper empirically investigates the effect of personalization and the psychological reactance on the intention to use information systems in the personalized recommendation context. Users' perception of personalization increases the usefulness of recommendation service while their perception of threat to freedom reduces the intention to use personalized recommendation service. Findings and implications are discussed.

• ETRI Journal
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• v.41 no.4
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• pp.536-548
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• 2019

In this study, an electronically steerable parasitic array radiator (ESPAR) antenna via analog radio frequency (RF) switches for a single RF chain MIMO system is presented. The proposed antenna elements are spaced at ${\lambda}/64$, and the antenna size is miniaturized via a dielectric radome. The optimum reactance load value is calculated via the beamforming load search algorithm. A switch simplifies the design and implementation of the reactance loads and does not require additional complex antenna matching circuits. The measured impedance bandwidth of the proposed ESPAR antenna is 1,500 MHz (1.75 GHz-3.25 GHz). The proposed antenna exhibits a beam pattern that is reconfigurable at 2.48 GHz due to changes in the reactance value, and the measured peak antenna gain is 4.8 dBi. The reception performance is measured by using a $4{\times}4$ BPSK signal. The measured average SNR is 17 dB when using the proposed ESPAR antenna as a transmitter, and the average SNR is 16.7 dB when using a four-conventional monopole antenna.

• The Journal of the Korea Contents Association
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• v.17 no.10
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• pp.94-101
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• 2017

This study is to compare and analyze the bioelectrical impedance values on the upper extremity (affected and non-affected side) in hemiplegic stroke patients. Experimental subjects were 24 stroke patients with hemiplegia undergoing stroke rehabilitation between October to November, 2015. Prediction marker, resistance, reactance, and phase angle were measured in the upper extremity (affected and non-affected side) of hemiplegic stroke patients, using MultiScan 5000, and then they were expressed as quantified values. The affected and non-affected side of upper extremity in stroke patients with hemiplegia exhibited significant differences in prediction marker, reactance, and phase angle (p<0.05). There were significant differences in the impedance values at the affected and non-affected side of hemiplegic stroke patients. Thus, the possibility of evaluating stroke patients undergoing clinical rehabilitation therapy was suggested.