• 한국중재학회지:중재연구
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• 제14권1호
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• pp.315-344
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• 2004

Although we try to increase the order of turn key construction for the international competitiveness strengthening, the construction quality advancement and the productivity enhancement of the public sectors, the problems of the domestic turn key systems are causing the hardships of all the participants and many possible disputes. The home turn key constructions have been activated since 1997. A lot of trial and error had been experienced in these days, and the turn key systems have been changed little by little. But the bases are continuously kept because of their reflecting all the participants' opinions. In the inner turn key constructions the problems of uniform types are repeatedly occurred, and, especially, many problems happen up to the stage of early stage owing to the specialties of the turn key construction. So the dispute factors of the Korean turn key constructions were abstracted through the literature searches, the site document examinations, the case studies and the interviews with the experts. When the technicians meeting the interior turn key construction for the first time and working here now are well acquainted with only these factors, many disputes will be prevented.

• 한국중재학회지:중재연구
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• 제15권1호
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• pp.95-112
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• 2005

In the inner turn key constructions the problems of uniform types are repeatedly occurred, and, especially, many problems happen up to the stage of pre-construction(from a bid to a contract) owing to the specialties of the turn key constructions. So the claim factors of the Korean turn key constructions were abstracted in antecedent paper. When the technicians meeting the interior turn key constructions for the first time and working here now are well acquainted with only these factors, many claims will be prevented. By analysing the degree of claims by claims factors through the questionnaires to the experts about the abstracted factors and surveying the amount of the claims through the case studies, what factors exerted how much of influence on the claims was tested and analyzed. Studying and Managing the factors affecting the claims much led the technicians in charge of internal turn key constructions to the prevention and the proper solution of the site claims.

• 한국건축시공학회지
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• 제6권1호
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• pp.93-99
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• 2006

In the inner turn key constructions the problems of uniform types are repeatedly occurred, and, especially, many problems happen up to the stage of pre-construction(from a bid to a contract) owing to the specialties of the turn key constructions. So the claim factors of the Korean turn key constructions were abstracted through the literature searches, the site document examinations, the case studies and the interviews with the experts. When the technicians meeting the interior turn key constructions for the first time and working here now are well acquainted with only these factors, many claims will be prevented. By analysing the degree of claims by claims factors through the questionnaires to the experts about the abstracted factors and surveying the amount of the claims through the case studies, what factors exerted how much of influence on the claims was tested and analyzed. Proposing the response devices to the factors affecting the claims much led the technicians in charge of internal turn key constructions to the prevention and the proper solution of the site claims.

• 한국중재학회지:중재연구
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• 제13권2호
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• pp.353-376
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• 2004

In the inner turn key constructions the problems of uniform types are repeatedly occurred, and, especially, many problems happen up to the stage of pre-construction(from a bid to a contract) owing to the specialties of the turn key constructions. So the claim factors of the Korean turn key constructions were abstracted through the literature searches, the site document examinations, the case studies and the interviews with the experts. When the technicians meeting the interior turn key constructions for the first time and working here now are well acquainted with only these factors, many claims will be prevented. By analysing the degree of claims by claims factors through the questionnaires to the experts about the abstracted factors and surveying the amount of the claims through the case studies, what factors exerted how much of influence on the claims was tested and analyzed. Proposing the response devices to the factors affecting the claims much led the technicians in charge of internal turn key constructions to the prevention and the proper solution of the site claims.

• Journal of Power Electronics
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• 제18권3호
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• pp.892-901
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• 2018

SiC MOSFETs have been used to improve system efficiency in high frequency converters due to their extremely high switching speed. However, this can result in undesirable parasitic oscillations in practical systems. In this paper, models of the key components are introduced first. Then, theoretical formulas are derived to calculate the switching oscillation frequencies after full turn-on and turn-off in clamped inductive circuits. Analysis indicates that the turn-on oscillation frequency depends on the power loop parasitic inductance and parasitic capacitances of the freewheeling diode and load inductor. On the other hand, the turn-off oscillation frequency is found to be determined by the output parasitic capacitance of the SiC MOSFET and power loop parasitic inductance. Moreover, the shifting regularity of the turn-off maximum peak voltage with a varying switching speed is investigated on the basis of time domain simulation. The distortion of the turn-on current is theoretically analyzed. Finally, experimental results verifying the above calculations and analyses are presented.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2002년도 학술대회지
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• pp.223-232
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• 2002

정부에서는 건설사업관리에 대한 법적 근거를 마련한 이후 후속적인 제도보완과 함께 시범사업을 선정하는 등 제도의 정착과 활성화에 노력하고 있다. 그러나 턴키사업에서 CM방식 적용의 경우 설계와 시공이 단일 책임 하에 이루어지는 계약의 특성상 CM 역할의 일부가 제한되고 현행 $\lceil$건설사업관리업무지침$\rfloor$에 턴키사업의 특성이 반영되지 않아 적용상의 어려움이 예상된다. 턴키사업은 그간의 적용을 통해 다양한 문제가 도출되고 있으며, 우리나라의 $\lceil$건설사업관리업무지침$\rfloor$은 미국CMAA의 CM서비스를 비교하여 그 내용이 포괄적이고 CM의 선계이전단계업무의 중요성을 간과하고 있다. 턴키사업에서 CM의 역할을 공사착공 이전까지를 연구범위로 '입찰준비단계', '입찰단계', '실시설계단계', '계약단계'로 구분하여 CM 업무를 규정하고, 제도상의 보완책을 제시하였으며 턴키사업의 CM 역할은 정서적 역할과 전문적 역할로 구분하여 그 내용을 고찰하여 CM적용을 통해 현행 턴키사업의 문제점에 대한 보안방안을 제시하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2004년도 하계학술발표 논문집
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• pp.192-192
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• 2004

• 공학교육연구
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• 제9권4호
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• pp.5-9
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• 2006

본 논문에서는 한남대학교 토목환경공학과 4학년 전공선택 과목인 상하수도공학에서 진행한 협동학습을 소개하였다. 도시 비점원 처리시설을 설계하는 문제중심 학습을 실시하면서 토목구조물의 설계-시공-감리를 통합하여 수주하는 턴키(turn-key) 제도를 모사하여 수업을 진행하였다. 수강생 25명을 4개 조로 나누었으며 각 조를 각각 하나의 회사로 가정하여 사장-임원-사원에 이르는 직급을 정하게 하였다. 발주공사에 대한 설계개념 정립에서부터 공사비용의 산정, 공정 계획, 설계, 응찰에 이르는 전 과정을 수업 중 설명하였으며 비점원오염물질 처리시설물 수주를 위하여 각 조간 경쟁하도록 하였다. 설계가 가장 우수하면서 입찰금액을 낮게 쓴 조가 공사를 수주하되 1인당 예상 이익으로 과목의 성적을 평가하였다. 강의 진행과 효과분석을 위하여 각 팀별로 1명씩을 초점그룹으로 선택하였으며 중점적으로 학기 중 면담을 실시하여 수업에 반영하였다. 학생들은 턴키 제도의 운용, 인사고과에 대한 인식이 향상되었으며 수업의 긴장감을 효과적으로 높일 수 있었으며, 복잡한 설계과제를 수행할 수 있었다.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권4호
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• pp.477-482
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• 2012

This paper describes a new rotor position sensorless control method for SRM drives based on an improved simplified flux linkage method. In the traditional simplified flux linkage method, every phases take turns conduction and current chopping control method is used. Every phases take turns conduction means turning on the incoming working phase while turning off the working phase. This conduction mode causes coupling between turn-on and turn-off angles, which goes against optimal efficiency or torque ripple minimization with sensorless speed control. In the improved simplified flux linkage method, turn-off angle is calculated by flux loop, the turn-on angle can be given arbitrarily and has no relations with the turn-off angle, and the current chopping control method is used. The speed and rotor position can be estimated then. Finally, a sensorless SRM speed control system and an experiment platform with DSP are built and validity of this method is confirmed.

• Journal of Power Electronics
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• 제10권2호
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• pp.132-137
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• 2010

Interleaving techniques are widely used to reduce input/output ripples and to increase the power capacity of boost converters operating in critical conduction mode. Two types of phase-shift control schemes are studied in this paper, the turn-on time shifting method and the turn-off time shifting method. It is found that although the turn-off time shifting method exhibits better performance, it suffers from sub-harmonic oscillations at high input voltages. To solve this problem, an intensive quantitative analysis of the sub-harmonic oscillation phenomenon is made in this paper. Based upon that, a novel modified turn off time shifting control scheme for interleaved boost converters operating in critical conduction mode is proposed. An important advantage of this scheme is that both the master phase and the slave phase can operate stably in critical conduction mode without any oscillations in the full input voltage range. This method is implemented with a FPGA based digital PWM control platform, and tests were carried out on a two-phase interleaved boost PFC converter prototype. Experimental results demonstrated the feasibility and performance of the proposed phase-shift control scheme.