• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.8
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• pp.31-40
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• 2009

This paper presents a design of a high performance DC-DC boost converter as a power module for SOC designs. It applied to this chip that reduced inductor and capacitor for integrating on a chip, and it operates with a switching frequency of 100MHz. It has reliability and stability in high switching frequency. The controller of DC-DC boost converter is designed by voltage-mode control method and compensated properly. The designed DC-DC converter is fabricated with the 0.18${\mu}m$ standard CMOS technology with a thick-gate oxide option. The overall die size is 8.14$mm^2$, and controller size is 1.15$mm^2$. The converter has the maximum efficiency over 76% for the output voltage of 4V and load current larger 300mA. The load regulation is 0.012% (0.5mV) for the load current change of 100mA.

• Journal of the Korean Home Economics Association
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• v.28 no.2
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• pp.91-106
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• 1990

This study focuses on consumers' advertising discriminatory competencies and the influencing facors. So the objects of this study are as follows : 1) to identify the overall level of advertising discriminatory competencies. 2) to examine if consumer attitude variables have significant effects on the ads. discriminatory competenceis. 3) to examine if the frequencies of contacting advertising variable have significant effects on the ads. discriminatory competencies. 4) to examine if socio-economics variables-age, educational level, monthly family income, occupational status-have significant effects on the ads. discriminatory competencies. 5) to find out the independent influence of variables related to the ads. discriminatory competencies. For this purpose, a survey was conducted using questionaires and advertisement papers. The data used in this study included 194 Homemakers living in Seoul. The ads. used in this study included ads. of diary products like foods, drinks, medicine, cosmetic, detergent in TV, radio, newspaper and magagine. Statistics were Frequency Distribution, Mean, percentile, ANOVA, Scheff -test, Pearsons' Correlation, Multiple Regrassion Analysis. Major findings were as follows : First, in 26 items(70%) of 37 items measured consumers' ads. discriminatory competencies, the rate of right answer was below 50%, so over the half of consumers were misleaded by the deceptive ads. Second, consumers' ads. discriminatory competencies differed significantly according to consumer attitude variables but no according to the frequency of contacting advertising. Third, according to socio-demographic variables-age, educational level, monthly family income, occupational status-advertising discriminatory competencies differed significantly. In group of lower age, higher educational level, higher income and professional occupation status, the level of ads. discriminatory competencies were high. Forth, the most influencing variabel on ads. disciriminatory competencies were eudcational level and in turn general attitude toward ads., attitude toward consumerism. This three variables explain 22.9% of dependent variable's variance. From these findings, the following suggestions are made, First, the consumer education offering informations and learing practical ads. discriminatory competencies should be conducted for all consumers wheather they are educated or not. Also the education to improve the consumer attitude must be. Second, considering misleading level, the business must make the regulatory standards and reinforce the regulation voluntarily, and by enforcing the regulation of ads. and deciding more diverse, objective and exact standards, the government should keep the consumer's right to know.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.2
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• pp.54-63
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• 2007

Recently, a fuel cell with low voltage and high current output characteristics is remarkable for new generation system. It needs both a DC-DC step-up converter and DC-AC inverter to be used in fuel cell generation system. Therefor, this paper, consists of an isolated DC-DC converter to boost the fuel cell voltage $380[V_{DC}]$ and a PWM inverter with LC filter to convent the DC voltage to single-phase $220[V_{AC}]$. Expressly, a tapped inductor filter with freewheeling diode is newly implemented in the output filter of the proposed high frequency isolated ZVZCS PWM DC-DC converter to suppress circulating current under the wide output voltage regulation range, thus to eliminate the switching and transformer turn-on/off over-short voltage or transient phenomena. Besides the efficiency of 93-97[%]is obtained over the wide output voltage regulation ranges and load variations.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.4
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• pp.384-394
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• 1999

This paper deals with a fixed frequency full-bridge inverter type DC-DC high-power converter with high frequency high voltage(HFHV) transformer-coupled stage, which operates under quasi-resonant ZVS transition priciple in spite of a wide PWM-based voltage regulation processing and largely-changed load conditions. This multi-resonant(MR) converter topology is composed of a series capacitor-connected parallel resonant tank which makes the most of parasitic circuit reactive components of HFHV transformer and two additional quasi-resonant pole circuits incorporated into the bridge legs. The soft-switching operation and practical efficacy of this new converter circuit using the latest IGBTs are actually ascertained through 50kV trially-produced converter system operating using 20kHz/30kHz high voltage(HV) transformers which is applied for driving the diagnostic HV X-ray tube load in medical equipments. It is proved from a practical point of view that the switching losses of IGBTs and their electrical dynamic stresses relating to EMI noise can be considerably reduced under a high frequency(HF) switching-based phase-shift PWM control process for a load setting requirements.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.301-306
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• 2010

Thesis is about RFID(Radio Frequency Identification) technology which is recently in the spotlight of overall industry including physical distribution. Most RFID systems in Korea are imported, and there are also problems in manpower. In order to prevent these kinds of problems, students made to get and easy access to RFID system. The purpose of is to solve the regulation problems. We made an application software to practice RFID system implemented, which have several modules so that it can be easy for users to understand RFID system. We also invented a system which makes student ID to help users understand how RFID system is implemented in real life.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.2
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• pp.63-70
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• 2002

Cholinergic modulation of GABAergic spontaneous miniature inhibitory postsynaptic currents (mIPSCs) by the activation of muscarine receptors was investigated in mechanically dissociated rat nucleus basalis of the Meynert neurons using the conventional whole-cell patch recording configuration. Muscarine $(10{\mu}M)$ reversibly and concentration-dependently decreased mIPSC frequency without affecting the current amplitude distribution. Muscarine action on GABAergic mIPSCs was completely blocked by $1{\mu}M$ methoctramine, a selective $M_2$ receptor antagonist, but not by $1{\mu}M$ pirenzepine, a selective $M_1$ receptor antagonist. NEM $(10{\mu}M),$ a G-protein uncoupler, attenuated the inhibitory action of muscarine on GABAergic mIPSC frequency. Muscarine still could decrease GABAergic mIPSC frequency even in the $Ca^{2+}-free$ external solution. However, the inhibitory action of muscarine on GABAergic mIPSCs was completely occluded in the presence of forskolin. The results suggest that muscarine acts presynaptically and reduces the probability of spontaneous GABA release, and that such muscarine-induced inhibitory action seems to be mediated by G-protein-coupled $M_2$ receptors, via the reduction of cAMP production. Accordingly, $M_2$ receptor-mediated disinhibition of nBM neurons might play one of important roles in the regulation of cholinergic outputs from nBM neurons as well as the excitability of nBM neurons themselves.

• Journal of Power Electronics
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• v.10 no.1
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• pp.27-33
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• 2010

This paper presents a bidirectional DC-DC converter suitable for low-voltage super capacitor-based electric energy storage systems. The DC-DC converter presented here consists of a full-bridge circuit and a current-fed push-pull circuit with a high frequency (HF) transformer-link. In order to reduce the device-conduction losses due to the large current of the super capacitor as well as unnecessary ringing, synchronous rectification is employed in the super capacitor-charging mode. A wide range of voltage regulation between the battery and the super capacitor can be realized by employing a Phase-Shifting (PS) Pulse Width Modulation (PWM) scheme in the full-bridge circuit for the super capacitor charging mode as well as the overlapping PWM scheme of the gate signals to the active power devices in the push-pull circuit for the super capacitor discharging mode. Essential performance of the bidirectional DC-DC converter is demonstrated with simulation and experiment results, and the practical effectiveness of the DC-DC converter is discussed.

• Nuclear Engineering and Technology
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• v.44 no.7
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• pp.745-754
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• 2012

The correlations between Large Early Release Frequency (LERF) and Early Fatality need to be investigated for risk-informed application and regulation. In Regulatory Guide (RG) -1.174, while there are decision-making criteria using the measures of Core Damage Frequency (CDF) and LERF, there are no specific criteria on LERF. Since there are both huge uncertainties and large costs needed in off-site consequence calculation, a LERF assessment methodology needs to be developed, and its correlation factor needs to be identified, for risk-informed decision-making. A new method for estimating off-site consequence has been presented and performed for assessing health effects caused by radioisotopes released from severe accidents of nuclear power plants in this study. The MACCS2 code is used for validating the source term quantitatively regarding health effects, depending on the release characteristics of radioisotopes during severe accidents. This study developed a method for identifying correlations between LERF and Early Fatality and validates the results of the model using the MACCS2 code. The results of this study may contribute to defining LERF and finding a measure for risk-informed regulations and risk-informed decision-making.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.555-559
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• 2003

Recently, in accordance with the commercialization of novel radio frequency utilization technologies, the radiated power must be rigorously limited for the purpose of protection of wireless facilities against frequency jamming or interference and for maintaining the quality of communication service. At present, the output power is measured from the conducted power for the domestic measurement criterion but is not a real radiated power and inaccurate. So, it is peformed to survey the more precisely accurate measurement scheme and analyze its criterion and methodology in comparison with foreign one. As a result of surveying and analyzing, it is concluded that the U.S. and E.U. is actually using the measurement method in consideration of terms of the Equivalent Isotropic Radiated Power(EIRP) and Effective Radiated power(ERP). In case of the frequency below 1 GHz, the half wave-length dipole antenna is used to measure the ERP and above 1 GHz the horn antenna as a reference antenna is used to measure the EIRP. Therefore, for the domestic purpose it is also necessary to take EIRP and ERP into consideration as a measurement criterion in order to make an accurate measurement and regulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.9A
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• pp.2141-2152
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• 1998

In this paper, we design and implement an indoor wireless modem using small signal of ISM band regulation, which can tranceive reliable data streams. We use direct sequence spead spectrum (DS-SS) signaling with synchronous BPSK and QPSK modulation, convolutional coding with viterbi decoding. The radio frequency module uses frequency devision duplexing in 900 MHz band, and the digital module is implemented with FPGAs for the purpose fo ASIC design. The perfomrance of our own acquistion and tracking circuit consisting digital matched filter and decision logic is proved by experiments, and the possibility of file transfer at indoor environment with the entrie system that the modem is connected the PC through RS-232C port is verified.