• Journal of the Korea Convergence Society
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• v.9 no.9
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• pp.353-362
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• 2018

The purpose of this study is to suggest a professional consensus on the topics that should be dealt with importantly in the movement program for the recovery of cancer patients in Korea. As a result of calculating the importance of the finalized movement program component, First, the opinions about the environment for the promotion of movement were suggested as pleasant facilities, natural lighting, rest room space, facilities aspect of environment friendly space, education about diseases, participation programs, health feedback, information handouts. Second, the opinions on the purpose of the movement program were suggested to promote prevention and early screening of cancer, education, sharing effective treatment methods of cancer patients, cognitive aspect and psychological support for accurate information transmission, stress relief, and improvement of quality of life. Third, the opinions on the consideration of the movement program suggested stress relieving, cancer patient's needs, correct information delivery, quality of life, and participation of cancer patients. Fourth, the problems of the movement program were presented with different physical characteristics, physical inconvenience, the patient side of passive participation, space narrowness and lack, space aspect of program exclusive space etc.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.8
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• pp.895-903
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• 2007

Design equations of DC blocks terminated in arbitrary impedances are newly suggested and a microstrip DC block is tested for the perfect matching. The DC block is a two-port passive component and the power excited at a port is transmitted into another port. However, all the excited power at the input can not be delivered to the output and therefore most of the conventional DC blocks can not be perfectly matched with arbitrary termination impedances. To solve the matching problem, its one-port equivalent resonant circuit model, front which design equations can be derived, is newly suggested. Using the derived design equations, any DC block can be designed, perfectly matched without any restriction of coupling coefficients. To verify the derived design equations, measurements were carried out and the results are in good agreement with prediction, showing insertion and return losses at 4.1 GHz are 0.82dB and -31dB, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.4
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• pp.298-308
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• 2017

This paper presents a Interleaved Buck Converter(IBC) system with Random PWM to reduce electromagnetic noise by harmonics. Swithced mode power supply generally controlled by high switching frequency have a electromagnetic interference(EMI) issue due to the high-voltage/high-current switching to regulate the voltage in buck converter. To solve the problem. we present a novel IBC system with PRBS. IBC system has two active switches with 180 phase difference that controll the cicuit with two PWM signal. IBC system may be disadventageous for the cost due to the addtion of one set of switch, but it has adventages of power distribution, current ripple cancellation, fast transient response, and passive component size reduction. To verify the validity of study, simulation program has been bulit using PSIM and the experimental results of IBC system using RPWM was compared with the conventinal PWM and randomized PWM.

• Journal of Advanced Navigation Technology
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• v.18 no.4
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• pp.359-363
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• 2014

This paper presents the design and performance of an unequal divider with physical separation and electrical isolation. This divider has a series $18{\Omega}$ resistor and 0.7 pF capacitor circuit between two quarter-wave transmission lines at half phase angle from input terminal. This design method was improved a physical isolation between output ports and easy connected other circuit because of unnecessary of extra transmission line. To show the validity of the unequal divider with complex isolation components, a 4:1 ratio unequal divider was designed and measured at center frequency of 2 GHz. The measured divider performances have the return loss of 17 dB, insertion loss of 1.5 dB and 7.7 dB, and isolation of 18 dB. Its performance is in good agreement with the simulated results.

• The Journal of the Acoustical Society of Korea
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• v.37 no.1
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• pp.39-45
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• 2018

Compressive sensing allows recovering an original signal which has a small dimension of the signal compared to the dimension of the entire signal in a short period of time through a small number of observations. In this paper, we proposed a method for detecting tonal signal which caused by the machinery component of a vessel such as an engine, gearbox, and support elements. The tonal signal can be modeled as the sparse signal in the frequency domain when it compares to whole spectrum range. Thus, the target tonal signal can be estimated by S-OMP (Simultaneous-Orthogonal Matching Pursuit) which is one of the sparse signal recovery algorithms. In simulation section, we showed that S-OMP algorithm estimated more precise frequencies than the conventional FFT (Fast Fourier Transform) thresholding algorithm in low SNR (Signal to Noise Ratio) region.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.4
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• pp.470-480
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• 2011

Analog ferrite phase shifters based on rectangular waveguides which are used as component of passive phased array system have high power handling capability, but it is heavy and has high cost to fabricate. In this paper, we propose an analog ferrite phase shifter using substrate integrated waveguide(SIW), which has low cost and is easy to fabricate because it uses printed circuit board(PCB) process. The proposed structure is fabricated by using centeral dielectric material removal for inserting a ferrite bar. The measured results show that the proposed structure has not only $5.1^{\circ}$/mm phase variation but also return loss variation under 12.9 dB. Therefore, it is expected that the proposed phase shifter can plays an role to reduce weight and to has low cost on the phased array system.

• Fire Science and Engineering
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• v.33 no.4
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• pp.70-76
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• 2019

This paper reports development of a low-power standalone heat detector using a Critical-Temperature Switch. The Critical-Temperature Switch, which is a thermally sensitive and passive component whose resistance decreases significantly at 70 ℃ due to a metal-insulator transition, provides reliable temperature measurements. This digital-like behavior of the Critical-Temperature Switch can detect fires without a microcontroller, meaning that it can minimize the power consumption of the standalone heat detector. The experimental results showed that the standalone heat detector using the Critical-Temperature Switch complied with the Notification of the National Emergency Management Agency. Compared to conventional standalone heat detectors, only 70% of the power was consumed monitoring the fires.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.35-44
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• 1998

In this paper, input LC filter design of diode rectifiers considering filter V A rating reduction has been propoesd. It consisted of an input LC parallel resonent tank whose inductor and capacitor values are se$.$ lected so that the input filter presents an infinite impedance to harmonic input ac current component. The operation of proposed input filter has been analyzed in detail under steady state conditions. Performance evaluation and related design data have been provided on Per Unit basis for the proper implementation of diode rectification system. Finally, Detailed input and output current analysis has shown that the proposed input filter yield high quality input ac current waveforms, in particular, high input power factor values and more reliabilty which reducing the V A rating of passive components as compared to the standard type LC filter.filter.

• Journal of Power Electronics
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• v.11 no.3
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• pp.360-368
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• 2011

This paper proposes an active frequency with a positive feedback in the d-q frame anti-islanding method suitable for a robust phase-locked loop (PLL) algorithm using the FFT concept. In general, PLL algorithms for grid-connected PV PCS use d-q transformation and controllers to make zero an imaginary part of the transformed voltage vector. In a real grid system, the grid voltage is not ideal. It may be unbalanced, noisy and have many harmonics. For these reasons, the d-q transformed components do not have a pure DC component. The controller tuning of a PLL algorithm is difficult. The proposed PLL algorithm using the FFT concept can use the strong noise cancelation characteristics of a FFT algorithm without a PI controller. Therefore, the proposed PLL algorithm has no gain-tuning of a PI controller, and it is hardly influenced by voltage drops, phase step changes and harmonics. Islanding prediction is a necessary feature of inverter-based photovoltaic (PV) systems in order to meet the stringent standard requirements for interconnection with an electrical grid. Both passive and active anti-islanding methods exist. Typically, active methods modify a given parameter, which also affects the shape and quality of the grid injected current. In this paper, the active anti-islanding algorithm for a grid-connected PV PCS uses positive feedback control in the d-q frame. The proposed PLL and anti-islanding algorithm are implemented for a 250kW PV PCS. This system has four DC/DC converters each with a 25kW power rating. This is only one-third of the total system power. The experimental results show that the proposed PLL, anti-islanding method and topology demonstrate good performance in a 250kW PV PCS.

• Biomolecules & Therapeutics
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• v.25 no.3
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• pp.249-258
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• 2017

To examine the effect of biflorin, a component of Syzygium aromaticum, on memory deficit, we introduced a scopolamine-induced cognitive deficit mouse model. A single administration of biflorin increased latency time in the passive avoidance task, ameliorated alternation behavior in the Y-maze, and increased exploration time in the Morris water maze task, indicating the improvement of cognitive behaviors against cholinergic dysfunction. The biflorin-induced reverse of latency in the scopolamine-treated group was attenuated by MK-801, an NMDA receptor antagonist. Biflorin also enhanced cognitive function in a naïve mouse model. To understand the mechanism of biflorin for memory amelioration, we performed Western blot. Biflorin increased the activation of protein kinase C-${\zeta}$ and its downstream signaling molecules in the hippocampus. These results suggest that biflorin ameliorates drug-induced memory impairment by modulation of protein kinase C-${\zeta}$ signaling in mice, implying that biflorin could function as a possible therapeutic agent for the treatment of cognitive problems.