• 대한토목학회논문집
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• 제14권4호
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• pp.897-905
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• 1994

건설공사 정보분류체계는 공사관리기법의 적용효과를 향상시킬 수 있는 하나의 도구로 활용될 수 있으며, 공사의 단계별 발생정보를 네트워크와 연계가 가능하도록 하고, 효과적인 원가관리로서 공사비를 절감시킬 수 있다. 본 연구에서는 이러한 공사관리기법에 적용될 수 있는 표준화된 건설공사 정보분류체계의 개발을 시도하고 있으며, 연구내용은 크게 다음의 3가지로 요약된다: (i) 토목공사 전체를 시설요소, 구조요소, 공사요소의 3단계로 분류하여 코드화한 공사분할체계의 개발, (ii) 적산과 공정 관리등에 관련되는 기타정보들을 포함한 통합 정보체계의 구축, (iii) 전산적용시 입력자료로 활용가능한 연관 데이타베이스의 구축. 본 연구결과 제안된 정보분류체계는 실무설계내역서 등과의 검증결과 공사의 각 단계별로 발생되는 정보들의 체계적이고 표준적인 관리를 가능하게 할 것으로 판단된다.

• Journal of electromagnetic engineering and science
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• 제8권3호
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• pp.129-133
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• 2008

An integrated passive device(IPD) technology by semi-insulating(SI)-GaAs-based fabrication has been developed to meet the ever increasing needs of size and cost reduction in wireless applications. This technology includes reliable NiCr thin film resistor, thick plated Cu/Au metal process to reduce resistive loss, high breakdown voltage metal-insulator-metal(MIM) capacitor due to a thinner dielectric thickness, lowest parasitic effect by multi air-bridged metal layers, air-bridges for inductor underpass and capacitor pick-up, and low chip cost by only 6 process layers. This paper presents the Wilkinson power divider with excellent performance for digital cellular system(DCS). The insertion loss of this power divider is - 0.43 dB and the port isolation greater than - 22 dB over the entire band. Return loss in input and output ports are - 23.4 dB and - 25.4 dB, respectively. The Wilkinson power divider based on SI-GaAs substrates is designed within die size of $1.42\;mm^2$.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2002년도 학술대회지
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• pp.367-370
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• 2002

건설 프로젝트의 초기단계에 타당성을 검토함에 있어서 공통가설공사의 경우 설계도서상에 표시가 되지 않거나, 시방서상에 간략하게 서술되어 있기 때문에 담당자의 경험 의존율이 다른 공종에 비해 높다. 이런 초기단계의 결전은 프로젝트의 진행과 더불어 많은 문제점들을 야기 시킬 가능성이 있다. 따라서 최근 활발히 논의가 되고 있는 기존 공사정보에 대한 실적 데이터베이스와 공통가설공사의 분류체계를 포함한 시스템을 개발하여 자료들을 분석, 활용함으로써 시공전(Pre-Construction) 단계의 공통가설공사에 대한 작업 및 원가 예측을 용이하게 하고, 후에 Feed Back 됨으로써 정확한 건설 프로젝트 타당성 분석을 가능케 하고자 한다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권4호
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• pp.231-237
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• 2006

This paper proposes an effective drive of high intensity discharge (HID) lamp ballast for cars. All control functions of the proposed ballast are implemented using a low-cost single chip microcontroller, PIC16C73 to optimize the total system size and to minimize cost through minimization of total component number. The proposed ballast generates high open-circuit voltage to ignite the lamp and is controlled to supply effectively the power required to shorten warm-up period after the breakdown. The DC-DC converter of the DC-AC converter part of the ballast utilizes the flyback converter topology that can minimize component number. Also, because to more minimize the ballast size, the transformer size must be minimized, for this, PWM (Pulse Width Modulation) pulses are generated with high frequency using the PWM module of the microcontroller. An analysis for this is explained, briefly. As if the operation of the lamp and ballast arrives at steady-state, then the ballast must AC-control the lamp, for this, the microcontroller utilizes the other PWM module. And the part related to the igniter is explained, briefly. It is shown through experimental results that the controller of the proposed ballast has good performance for the HID lamp for cars.

• International Journal of Reliability and Applications
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• 제11권2호
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• pp.89-106
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• 2010

This paper deals with the reliability and availability characteristics of three different series system configurations with warm standby components and a repairable service station. The failure time of the primary and warm standby are assumed to be exponentially distributed with parameters ${\lambda}$ and ${\alpha}$ respectively. The repair time distribution of each server is also exponentially distributed with parameter ${\mu}$. The breakdown time and the repair time of the service station are also assumed exponentially distributed with parameters ${\gamma}$ and ${\beta}$ respectively. We derive the reliability dependent on time, availability dependent on time, the mean time to failure, $MTTF_i$, and the steady-state availability $A_i$(${\infty}$) for three configurations and perform comparisons. Comparisons are made for specific values of distribution parameters and of the cost of the components. The three configurations are ranked based on: $MTTF_i$, $A_i$(${\infty}$), and $C_i/B_i$ where $B_i$ is either $MTTF_i$ or $A_i$(${\infty}$).

• 대한안전경영과학회지
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• 제7권1호
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• pp.101-115
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• 2005

This study deals with the procedure of safety improvement, productivity increase ,and tact-time reduction through setting up the system about preventive maintenance. Actually, it is hard to establish and carry out preventive maintenance, even though we recognize the importance of the system concerning time, cost, labor, and so forth. In this study in the viewpoint of cost we are for achieving maximum efficiency by change and reduction of planning process adapted to the special work group. At first we briefly will mention the kind ,the necessity ,and the concept of preventive maintenance ,and then divide the equipment used in the assembly line into the two whether it is necessary or not by way of estimating the breakdown loss ,comparing with general establishment of preventive maintenance and modifying it to the case. At the second step we will establish the operation system of plan management related to production and quality in the special case. Check period and category will be set by dividing the assembly equipment into LCL and Focus in the third step. The forth step will contain the operation procedure in detail. And then we must make check and repair record periodically. Finally, on the basis of the record the selection of checking of significance will be conducted. This results in safety improvement, tact time reduction, and productivity improvement.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2004년도 추계학술대회
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• pp.131-141
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• 2004

This study deals with the procedure of safety improvement, productivity increase, and tact-time reduction through setting up the system about preventive maintenance. Actually, it is hard to establish and carry out preventive maintenance, even though we recognize the importance of the system concerning time, cost, labor, and so forth. In this study in the viewpoint of cost we are for achieving maximum efficiency by change and reduction of planning process adapted to the special work group. At first we briefly will mention the kind, the necessity, and the concept of preventive maintenance, and then divide the equipment used in the assembly line into the two whether it is necessary or not by way of estimating the breakdown loss, comparing with general establishment of preventive maintenance and modifying it to the case. At the second step we will establish the operation system of plan management related to production and quality in the special case. Check period and category will be set by dividing the assembly equipment into LCL and Focus in the third step. The forth step will contain the operation procedure in detail. And then we must make check and repair record periodically. Finally, on the basis of the record the selection of checking of significance will be conducted. This results in safety improvement, tact time reduction, and productivity improvement.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2007년도 정기학술발표대회 논문집
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• pp.917-920
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• 2007

우리나라의 민간투자 사업은 잦은 제도변경으로 많은 혼란을 격고 있지만, 2005년 1월 사회기반시설의 민간투자법 개정으로 공공서비스시설을 대중에게 제공할 수 있는 새로운 민간투자방식은 BTL(Build Transfer Lease)이 국내건설시장에 도입되었다. BTL사업은 계획에서 유지관리까지 사업의 수명주기 전 과정을 대상으로 포괄적 형태의 사업을 수행하는 것으로 사업자의 역할과 수행능력에 따라 사업의 성패가 좌우 된다. 따라서, 본 연구에서는 효율적인 BTL사업의 추진에 필요한 명확한 시스템 기준을 분석하여 사업수행의 정확성을 검증할 수 있는데 그 목적이 있다.

• 토지주택연구
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• 제2권4호
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• pp.355-365
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• 2011

Construction duration is very important as a factor which comprises three axises of construction management with quality and cost in construction project. In general project condition, construction duration is optimized while minimizing construction cost and securing required quality. However, in case of insufficient project time duration or delayed projects, project progress management is different from those of normal projects. These project areas need solutions to complete work within a given completion day. To time shortening the current duration of each typical floor of structural framework in apartment construction is investigated, and a basic time schedule planning for typical floor of structural framework in normal projects is planned. This study proposed 3 ways for time shortening of urgent project or insufficient construction duration project. Also, This study proposed detailed time shortening method and technical solution conditions while time is shortened.

• 대한조선학회논문집
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• 제56권1호
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• pp.1-10
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• 2019

Naval ship design and related other activities can be characterized by the complexity of the interactions among products, activities, and disciplines. Such complexities often result in inferior designs, cost overrun, and late-delivery. Hence there exist tremendous interests in both improving the design process itself and optimizing the interactions among design activities. This paper looks at the complexity of designing naval ships thereby leading to the innovation of current ship design practices using design structure matrix. It can be used to induce the optimal ordering of design activities as well as identify sources of complexities. The method presented here identifies coupled design activities useful for reducing the complexity of naval ship design as well as optimally reordering design activities. This paper recommends the use of design structure matrix method suitable for numerically optimizing the concept design process of naval ship, and reducing cost and time required in designing naval ships by modeling and analyzing the design activities and engineering tasks, defined in systems engineering planning documents.