• Journal of the Korean Institute of Telematics and Electronics
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• v.11 no.3
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• pp.1-14
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• 1974

The gain stability of the nuclear pulse linear amplifiers with feedback for such a fast pulse input as the step voltage or the nuclear radiation detector pulse is analysed in detail. The expression is derived which describes the waveform at the anode circuit of the photomultiplier tube which is a part of the nuclear radiation detector. It is analysed and compared when the feedback amplifier has one and two time-constants. When these fast input pulse voltages are applied to the feedback amplifier, the effects of feedback in linearity and stability of the output voltage appear only after two or three rise-times of the amplifier, And it is proved that in order to reduce this limitation, the rise time of the feedback amplifier shou1d be less than the input pulse width. It is also shown that the above theory can be applied directly to the voltage-shunt feedback amplifier stages designed as the basic amplifier of the linear amplifier, and that the gain stability is more improved for the smaller input impedance of this amplifier stage.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.5
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• pp.201-206
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• 2015

A new electronically stopband tunable filter is proposed with three-input single-output using Operational Transconductance Amplifier (OTA) in this paper. The proposed filter provides band pass, low pass and high pass multifunctional responses. Centre frequency ($f_c$) and quality factor (Q) of the realized filters could independently tuned without disturbing each other. Various network sensitivity and non-ideal characteristic analysis are done to check the sensitivity and parasitic effect of different circuit parameters. The CMOS realization of filter is done with 1.8V-0.18um process parameters and HSPICE simulation results are presented to assert the presented theory.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.78-81
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• 2000

A new type low-pass filter design method based on a coupled line and transmission line theory is proposed to suppress harmonics by attenuation poles in the stop band The design formula are derived using the equivalent circuit of a coupled transmission line. The new low-pass filter structure is shown to have attractive properties such as compact size, wide stop band range and low insertion loss. The seventh-order low-pass filter designed by present method Ins a cutoff frequency of 0.9 GHz with a 0.01 dB ripple level. The coupled line type low-pass filter with stripline configuration was fabricated by using a high-temperature superconducting (HTS ; $YBa_2Cu_3O_{7-x}$) thin film on MgO(100) substrate. Since the HTS coupled line type low-pass filter was proposed with five attenuation poles in stop band such as 1.8, 2.5, 4, 5.5, 62 GHz. The fabricated low-pass filter has improved the attenuation characteristics up to seven times of the cutoff frequency Bemuse of good rejection of the spurious signals and harmonics, our low-pass filter is applicable to mobile base station systems such as cellular, personal communication systems and international mobile telecommunication(IMT)-2000 systems.

• The Journal of Korean Physical Therapy
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• v.13 no.3
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• pp.509-527
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• 2001

The Sun's ray is composed of Infrared(49%), Visible light(40%) and Ultra violet(11%), however the ray getting to the earth is FIR(Far infrared; 60%), IR(Infrared; 20%), and UV(Ultra Violet; 20%). Human beings has utilized FIR already from time immemorial. Hershel found out Infrared for the first time. in the Industrial Revolution the Infrared and FIR had been begun to use making products. In these days, with contemporary science FIR would be begun to clear up the implication in the human body and organic compound. IR classified by wavelength three parts NlR, MIR, FIR. There is FIR which is radiated from healthy human body the wave length is 8-l4m. The human body is composed of proteins which get easily changed by a thermal factor (about 42 $^{\circ}$C over). FIR with low temperature can deeply penetrate on the human body composed things without troublesomes, since FIR has effectively operated on the human body at low temperature (35-40 $^{\circ}$C). When FlR penetrated on the human body. it would inhibit the abnormal genes and cells expression, and then information of DNA and RNA would be reexpressed for arranging DNA and RNA abnormal state. As FlR's receptors in the body, it could be presumed that N-glycosyl linkage of purine and deoxyribose, RNA splicing process, and Heat shock protein. To take the FIR which was a optimized wavewlength and strength, at first, we induced the characteristic algorithm and the computerized programing. Then we formed that the formular of optimized FIR with physical, mathematical logic and theory. especially, Plank, Kirchhoff, Wien, Stefan-Boltzmann's logic and law. In the long run, the formular was induced with integration mathematical, since we had to know the molecular wavelength. Based on the induced formular as above, we programmed the optimized FlR radiating computerized program. In this research, we designed the eletronic circuit f3r interfacing with human body to diagnosis and treatment with FIR sensor which radiated FIR wavelength optimized.

• Journal of the Korean Society for Nondestructive Testing
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• v.17 no.4
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• pp.262-269
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• 1997

An eddy current probe ($8{\times}1$ multiple-element, surface scan) was successfully designed and fabricated at the KEPRI using the impedance equivalent circuit theory. The probe is intended for the detection of circumferential deformations (cross-section view) of the heat exchanger tubing that can occur due to corrosion, erosion, and denting. Optimum design parameters providing the highest sensitivity and signal-to-noise ratio, such as the coil dimensions, electrical characteristics, and test frequencies, were determined based on initial laboratory experiments conducted on the test specimen (SS304 tubing: OD : 9.68mm, wall-thickness : 0.47mm) containing artificial flaws (e.g., dents and corroded surface on tube OD) using the available Zetec-made probe. Using this parameters, a new probe was made and tested on an unknown specimen. The result indicated that the new probe is capable of detecting the circumferential deformation with the error of ${\pm}0.2%$ (0.022mm) of the tube O.D.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.12
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• pp.21-30
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• 1999

Several kinds of design method for the hairpin type band-pass filter have been reported. The conventional design methods have some restrictions in characteristic impedance of coupled line section, which provide complexities to designer. In this paper, the novel design formulas for the hairpin type band pass filter have been derived and proposed to resolve the problems of the reported design methods. By employing the equivalent circuit of the coupled line section and band pass filter design theory, the design procedures and formulas are derived. The hairpin type RX/TX band pass filters for the IMT-2000 service have been designed, fabricated with duplexer configuration, and then measured to show the validity of the proposed design method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.12
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• pp.115-124
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• 2004

In this paper, we introduce the advanced compact transmission line with periodic stepped stubs. They are more effective than normal stubs in ATL. The short stepped stubs loading of transmission line work as effective shunt capacitance and that was proved by equivalent circuit based on transmission line theory and quasi-static analysis. And the compact branch-line coupler and the compact rat-race coupler via proposed compact microstrip line were designed at 1.8 ㎓. They have 677 ㎟ and 913 ㎟, respectively, and they are 62% and 45% of normal design.

• Journal of Navigation and Port Research
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• v.34 no.10
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• pp.763-768
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• 2010

Today the light of mankind since the dawn of mankind and that they were living "lives" on the huge influence across space is a dynamic energy. Because of this, when all human beings with the light and you can feel more comfortable with a stable mind to the beauty and the pursuit of happiness is to have instincts. In this paper, a fuzzy control system using a combination of external environmental factors, respectively, the conversion of quantitative uncertainty information into the LED lighting is designed to express algorithms, available in indoor circadian control circuit was designed and fabricated LED. Factor in the external environment temperature, humidity, and light intensity values to the controller through the sensor to accept these values and the optimal values for lighting the fuzzy control algorithm is converted into human emotion to feel comfortable to express through the dimming control LED lighting.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.1-10
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• 2009

As a demand for the portable device requiring smaller size and better performance is in hike, reducing the size of conventionally used planar 2 dimensional chip cannot be a solution for the enhancement of the semiconductor chip technology due to an increase in RC delay among interconnects. To address this problem, a new technology - "3 dimensional (3D) IC chip stack" - has been emerging. For the integration of the technology, several new key unit processes (e.g., silicon through via, wafer thinning and wafer alignment and bonding) should be developed and much effort is being made to achieve the goal. As a result of such efforts, 4 and 8 chip-stacked DRAM and NAND structures and a system stacking CPU and memory chips vertically were successfully developed. In this article, basic theory, configurations and key unit processes for the 3D IC chip integration, and a current tendency of the technology are explained. Future opportunities and directions are also discussed.

• Journal of Engineering Education Research
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• v.4 no.1
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• pp.79-87
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• 2001

In this paper, we proposed a new education plan of electronics engineering in vocational high-school. And the new proposed education plan is applied to electronic circuit theory education which is known to be a very difficult subject. It is the inventive education using PSPICE and EWB that is assistant to study program. Also, multimedia is used to improve education of electronic engineering in vocational high-school. The effectiveness for the proposed education is investigated by using the questionnaire. After the inventive education, students and teachers are very improved and encouraged in terms of interest, understanding and attitude of study. Specially, students showed strong interest in the education linked with the university curriculum.