• 정보학연구
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• 제5권2호
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• pp.47-54
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• 2002

본 논문의 목적은 IEEE 802.11g에서 제안하는 OFDM 소음과 동조화 에러, 256-State 2/3 2진법 Convoulutional 8-PSK Modulations, FEC 코딩, PBCC를 이용하여 5GHz Band FHSS 방식의 범주에 속하는 12Mbps의 속도를 2.4GHz ISM Band 대역에서 DSSS 방식으로 동일한 속도로 작동하는 전송장치 모델을 구현하여 현재 IEEE에서 표준안 제정중인 20Mbps DSSS의 일반화에 응용될 수 있도록 하였다.

• 전기학회논문지P
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• 제51권4호
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• pp.186-192
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• 2002

In this paper, interleaved boost power factor corrector(IBPFC) is applied as a pre-regulator in switch mode power supply. IBPFC can reduce input current ripple and effectively increase the switching frequency without increasing the switching losses, because input current is divided each 50% by two switching devices. IBPFC can be classified as three cases by duty ratio condition in continuous current mode and be carried out state space average modeling. According to the modeling, steady and transient state analysis is performed by steady elements and perturbation element. Control transfer function is derived for design of control system.

• 한국공작기계학회논문집
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• 제12권5호
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• pp.80-87
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• 2003

Air partial pressure ratio and inlet air mass flow are influenced by water vapor and gaseous fuel in mixture on Compressed Natural Gas (CNG) engines. In this paper, the effects of the water vapor and the gaseous fuel that change the air mass flow and the air-fuel ratio are studied. Effective air mass ratio is defined as the air mass flow divided by mixture mass flow, and also it is applied to the estimation of the inlet air mass flow and the air-fuel ratio. The presence of the gaseous fuel and the water vapor in the mixture reduces the air partial pressure and the effective air mass ratio of the CNG engines. The experimental results for the CNG engine show that estimation of the air-fuel ratio based upon the effective air mass ratio is more accurate than that of a normal mode.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3085-3089
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• 2008

In order to reduce NOx and Soot emissions simultaneously, characteristics of diesel spray and combustion were investigated by numerical simulation with StarCD in this paper. This work focuses on effect of Spin Injection. A simulation model of combustion, spray and emissions is developed for heavy duty marine diesel engine application. Simulation is performed with change of spray angle between first and second directions at fixed engine speed, injection timing, injection duration and etc. The results show that Spin Spray Injection method can reduce NOx emission. And the results show that the 1st injection considerably interfere with 2nd injection characteristics.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.391-392
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• 2012

본 논문에서는 페이저 변환을 통한 주파수-시비율-가변형 이중 출력 LLC 공진형 컨버터의 포락선 모델을 제시한다. 이를 이용하면 제안 회로의 대신호 및 소신호 특성을 쉽게 파악할 수 있을 뿐 아니라, 전달 함수의 정확한 수학적 해석을 통해 보상기의 설계가 용이해지는 장점이 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.168-174
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• 2001

In this paper, a new space vector RPPWM (Random Position PWM) is proposed. In the proposed RPPWM, each of three phase pulses is located randomly in each switching interval. Based on the space vector modulation technique, the duty ratio of the pulses is calculated. Along with the randomization of the PWM pulses, we can obtain the effects of spread spectra of voltage, current as in the case of randomly changed switching frequency. To verify the validity of the proposed RPPWM, simulation study was tried using Matlab/simulink. The main model described in Simulink block diagrams includes the space vector modulation block, pulse position randomization block, inverter block, 3 phase induction motor block, and so on. By the simulation study, the harmonics of the output voltage, and the current of inverter are predicted in different PWM methods- SVPWM, LLPWM, proposed RPPWM.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1474-1476
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• 2005

Because MCCB, ELB, etc. discharge both technical and economical duty, it is important that the study of circuit breaker guarantee high-performance and realize the power distribution system with reliability. Because of complexity electrical equipment, the accident with imbalance and flicker occur often according to technical improvement. However, study of accident with harmonics remains. In this paper, the essential characteristic of circuit breaker is introduced. To analysis operation of circuit breaker, theoretical model and several simulations have been performed.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2008년도 추계학술대회
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• pp.275-285
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• 2008

National technical qualification does not recognised degree of working-career in labor market and an industrial field situation. National qualification is supply to nurture expert manpower and accomplish of self-development and a duty accomplishment ability improvement at a side of personal. So, This study is purposed to find that a method for recognition of working-career on the national technical qualification system. According to, this study is designed to questionnaire with BSC(Balaced ScoreCard), SEM(Structure Equation Model) with the delphi method, and is analysed using the AMOS 7.0 program package. Finally, This study is suggested growing to qualification standard for an examination a degree of master craftsman only under the change of national qualification systematization as a standard to operation and control.

• 정보보호학회논문지
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• 제10권3호
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• pp.49-62
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• 2000

Role-Based Access Control(RBAC) has recently received considerable attention as a alternative to traditional discretionary and mandatory access control to apply variant organizations function hierarchy of commercial or govemment. Also RBAC provides a delegation that is one of control principles in organization. In general delegation occurring in real organization is performed by an user giving permissions to another user. But, RBAC cannot implement these user-level delegation correctly. And delegation result in security problem such as destroying separation of duty policy information disclosure due to inappro-priate delegation. Besides security adminsitrator directly deals with that problem. In this thesis we suggests some methods that is created by the user.

• 한국주거학회논문집
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• 제26권2호
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• pp.67-79
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• 2015

As the Korean construction market in the apartment housing has changed to a housing consumer focused market, interest and importance on efficient use and management on existing buildings has increased rather than demand for new buildings. Interest of housing consumers on apartment house quality has increased in this market paradigm, and this spontaneously is connected to quality flaw related defect disputes and lawsuits that the importance of defect diagnosis has continuously increased. This defect diagnosis is directly connected to maintenance charges in defect dispute and lawsuit processes that rather objective and highly credible progress of duty is required. However, most defect diagnosis firms today that progress defect diagnosis are using different diagnosis methods and depend on the experience of experienced professionals that there is no standardized defect diagnosis process. Therefore, the purpose of this study is to provide common defect diagnosis process model for defect diagnosis firms utilizing the BPMN (Business Process Modeling Notation) modeling method. It is expected that this will contribute to professional and reliable task performances of concerned defect diagnosis workers. Furthermore, it is expected that design lawsuit damage will be substantially reduced by standardizing defect diagnosis processes.