• 전자공학회논문지 IE
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• 제47권3호
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• pp.14-18
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• 2010

본 논문은 휴대용 배터리 구동시스템을 위한 다양한 출력전압(5-7V,100mA)을 가지는 CMOS DC-DC 변환기를 제안한다. 제안하는 DC-DC 변환기는 Pulse-Frequency Modulation (PFM) 방식을 사용하였고, 기준전압회로, 피드백 저항, 컨트롤러, 내부 파형발생기를 사용하였다. 2개의 외부 수동 소자들 (L,C)을 가진 집적화된 DC-DC 변환기는 0.5um 2-poly 4-metal CMOS 공정에서 설계 되었고 PDA, 휴대폰, 노트북 등에 적용 가능하다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권3호
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• pp.151-160
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• 2007

We report the label-free biomolecules detection based on nanomechanical micro cantilevers operated in dynamic mode for detection of two marker proteins (myoglobin and creatin kinase-MB (CK-MB)) of acute myocardical infarctions. When the specific binding between the antigen and its antibody occurred on the fuctionalized microcantilever surface, mechanical response (i.e. resonant frequency) of microcantilevers was changed in lower frequency range. We performed the label-free biomolecules detection of myoglobin and CK-MB antigen in the low concentration (clinical threshold concentration range) as much as 1 ng/ml from measuring the dynamic response change of micro cantilevers caused by the intermolecular force. Moreover, we estimate the surface stress on the dynamic microcantilevers generated by specific antibody-antigen binding. It is suggested that our dynamic microcantilevers may enable one to use the sensitive label-free biomolecules detection for application to the disease diagnosis system based on mechanical immuno-sensor.

• 한국입자에어로졸학회지
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• 제10권1호
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• pp.27-31
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• 2014

A simple bimodal model has been developed to analyze charged particle coagulation by modifying previously suggested bimdal model for evolution of particle generation and growth. In the present model, two monodisperse modes are used and 40 charge nodes are assigned to each mode to account both change of the particle size and charge distribution. In addition, we also implemented the effect of electrostatic dispersion loss in the present model. Based on the developed model, we analyzed coagulation of asymmetric bipolar charged particles by computing evolutions of particle number concentration, geometric mean diameter of particles, charge asymmetric ratio and geometric standard deviation of particle size distribution for various initial charge asymmetric ratios. The number concentration of asymmetric bipolar charged particles decreases faster than that of neutral particles but that does not give faster growth of particles since the electrostatic dispersion loss overwhelms particle growth by coagulation.

• International Journal of Concrete Structures and Materials
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• 제11권2호
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• pp.247-259
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• 2017

This paper presents a fatigue assessment model that was developed for corroded reinforced concrete (RC) beams strengthened using prestressed carbon fiber-reinforced polymer (CFRP) sheets. The proposed model considers the fatigue properties of the constituent materials as well as the section equilibrium. The model provides a rational approach that can be used to explicitly assess the failure mode, fatigue life, fatigue strength, stiffness, and post-fatigue ultimate capacity of corroded beams strengthened with prestressed CFRP. A parametric analysis demonstrated that the controlling factor for the fatigue behavior of the beams is the fatigue behavior of the corroded steel bars. Strengthening with one layer of non-prestressed CFRP sheets restored the fatigue behavior of beams with rebar at a low corrosion degree to the level of the uncorroded beams, while strengthening with 20- and 30%-prestressed CFRP sheets restored the fatigue behavior of the beams with medium and high corrosion degrees, respectively, to the values of the uncorroded beams. Under cyclic fatigue loading, the factors for the strengthening design of corroded RC beams fall in the order of stiffness, fatigue life, fatigue strength, and ultimate capacity.

• 한국안전학회지
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• 제29권3호
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• pp.85-90
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• 2014

The purpose of this study is to analysis the 3 differential size of the interior space for impulse noise. To achieve this goal the 3 kinds (27, 35, $50m^3$) of interior space were performed comparing the impulse noise. Result of this study, the standard error of the mean peak sound pressure of value from 0.19 to 0.27dB and there was no significant difference (p<0.01). And B-duration is significant differences (P<0.01) range from 3.98 to 7.93ms. This is respectively less than 10ms. These findings are confirmed in accordance by the 3 differential space size of the indoor-impulse noise due to 0.3 dB or less, so there was no difference to the operational influence. And also below 100 Hz were found fundamental mode frequency analysis. Results were matched with calculated theoretical values.

• 정보통신설비학회논문지
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• 제10권1호
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• pp.14-26
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• 2011

광 가입자용 송신 장치는 가입자 접속부의 ATM(Asynchronous Transfer Mode) 계층으로부터 ATM 셀을 비동기적인 방법으로 FIFO(First In, First Out)를 통해 수신하여 Idle/Unasigned 셀의 삽입, 셀에 대한 HEC(Header Error Correction) 계산, 그리고 셀 페이로드에 대한 스크램블링을 통해 VC4 신호 페이로드에 사상한다. 이때 VC4 POH(Path Over Head)상의 H4 바이트에 의해 셀의 시작점을 지시하고 동시에 POH 오버헤드에 대한 생성, 삽입을 통해 VC4 신호를 형성한다. 이 신호는 AU4 포인터 생성부에서 VC4의 시작점 J1을 생성하여 AUG버스를 통해 STM-1 신호 생성 부에서 프레임 형태로 출력된 후 155Mbps 속도로 광 신호로 변환되어 송신된다.

• 정보보호학회논문지
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• 제24권4호
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• pp.753-763
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• 2014

최근 금융기관 및 대형 유통업체 등에서 대량의 개인정보유출사고가 연이어 발생하고, 그 피해는 날로 늘어나는 추세에 있다. 이에 따라 개인식별정보를 암호화하도록 강제하는 등 규제가 강화되고 있다. 이러한 개인정보를 암호화하는데 있어서 효율적인 기술이 형태보존암호화이다. 일반적인 암호화방식은 입력 데이터 길이보다 출력 데이터 길이가 확장되며 형태가 변경된다. 형태보존암호화는 입력 데이터의 길이와 형태를 보존해주기 때문에 데이터베이스 및 응용프로그램 수정을 최소화하는 효율적인 방식이다. 본 논문에서는 블록암호 운영모드를 이용한 개인정보 암호화에 효율적인 형태보존암호화방식을 새롭게 제안한다.

• Journal of Power Electronics
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• 제16권3호
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• pp.1200-1208
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• 2016

Planar electromagnetic interference (EMI) filter has significant engineering significance to power electronic system integration and miniaturization. However, the value of differential mode capacitance cannot meet the demand of noise suppression because of the size limit of ceramics. In this case, the EMI filter of novel multilayers is recommended to address this issue. A novel integrated structure of EMI filter based on multilayer ceramic is proposed in this study. The inductance and capacitance of the new structure can be designed separately, which is an advantage in manufacturing. Insertion loss is measured more closely to the actual situation in this study, which is different from the condition where source and load impedances are both 50 Ω. In the process of designing a novel EMI filter, noise impedance is considered. Moreover, the prototype is created and applied to a small switching power supply, which verifies the effectiveness of the developed EMI filter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.51-53
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• 2018

This paper describes the design and implementation of a circuit consisting of a simmer power supply unit and a series trigger unit that can be applicable to xenon lamp driving. An LCC resonant converter based on the continuous conduction mode (CCM) is applied to the simmer circuit and by using the current output control it is possible to maintain the ionization of the lamp which has the negative resistance load characteristic. At the same time, in order to generate a high voltage, a series trigger circuit which has a number of capacitors and diodes is designed. The generated high trigger output voltage could ionize the xenon gas. This paper explains the configuration and features of the integrated circuit system, and verifies the proposed design and stable operation of the xenon lamp. The experimental and simulation results show the not only rationality but also stability of the proposed circuit.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 추계학술대회
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• pp.46-48
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• 2019

본 논문은 Discontinuous Conduction Mode(DCM) 플라이백 컨버터로 생성한 고전압 펄스를 스파크 갭으로 펄스 상승 시간을 줄이는 방법에 관하여 다룬다. 이러한 방법으로 생성된 빠른 상승률 특성을 가지는 고전압 펄스 전원장치는 친환경 가스 처리 분야에 사용할 수 있다. 기존 스태킹 구조의 펄스 전원 장치는 많은 수의 스위치들과 에너지 저장 소자가 필요하므로 부피가 커지고 제조 단가가 증가하는 반면, 분 논문에 제안된 전원 장치는 구조를 단순화하여 전체 시스템의 소형화 및 제조 단가를 낮춘 점을 특징으로 한다. 제안된 설계 토폴로지는 플라이백 변압기 2차 측에 다이오드의 사용 유무에 따라 두 개의 변형된 회로로 응용 가능 하다. 변압기 2차측에 다이오드를 사용하면, 음의 성분 없이 깨끗한 고전압 출력 펄스를 만들 수 있지만 사용한 다이오드의 전압 정격을 고려해야 한다. 다이오드를 사용하지 않는다면, 고전압 출력 펄스에 음의 성분이 발생하지만 비용과 부피를 최대한 줄일 수 있다. PSIM 시뮬레이션을 사용하여 제안하는 전원 장치의 23kV, 0.5 ㎲, 10 ns rising time의 출력 펄스 발생 성능을 검증하고, 다이오드 사용에 따른 출력 펄스의 차이점을 비교하였다.