• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2000년도 학술대회논문집
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• pp.235-240
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• 2000

This paper presents the reasonable method for electric power management through efficient use of electricity. With a rapid of national economics and living standard, electrical energy consumption markedly increased. Especially it is increased electrical energy consumption in commercial buildings and thus an energy conservation through efficient use of electricity became more important.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.486_487
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• 2009

This paper presents a method for optimal operation to improve reliability of MicroGrid systems considering load types and interruption cost. The objective functions such as power losses cost, operation cost of dispersed generations, power purchasing cost, and interruption cost are minimized for reliability improvement and efficient operation. The several indices for reliability evaluation are improved by renewable energy sources installation.

• 한국해양공학회지
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• 제29권2호
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• pp.135-142
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• 2015

The float over method is the most preferred method for installing heavy topside onto a jacket platform. A very complex platform with multiple jacket structures on a specific field requires multiple installation procedures. This study validated the installation of two topsides using a single installation barge to reduce the operation and installation cost. The hydrodynamic properties of the installation barge during the installation of two topsides were calculated. The tension and fender forces during docking were investigated to show the validity of the proposed dual topside installation method. In conclusion, the operational safety of the proposed procedure was validated through the calculation of the motion of the installation vessel and loads on the jacket legs.

• 한국건축시공학회지
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• 제12권3호
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• pp.358-368
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• 2012

On most construction sites, the arrangement of tower cranes is decided by site engineers based on their own experience, which can cause cost overruns and delays in the lifting work. Although many researchers have conducted studies on tower crane arrangement using computer modeling and knowledge-based expert systems as well as mathematical models, no research has aimed to develop an algorithm to identify an optimum solution among several alternatives for installation areas of tower cranes satisfying the conditions of lifting work. The objective of this study is to develop an automatic arrangement algorithm for tower cranes used in high-rise apartment construction. First, as a new concept, a possible installation area of tower cranes was suggested. Second, after proposing several alternatives based on the installation points suggested in this study, an algorithm analyzing the economic feasibility of tower cranes was developed considering the rental, installation and removal costs. Third, a case study was conducted to prove the validity of the developed algorithm for selecting and installing an effective set of tower cranes at minimum cost.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 추계학술대회 논문집
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• pp.263-266
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• 2009

In the photovoltaic applications, MPPT(maximum power point tracking) method is essential due to the non-lineality of photovoltaic output characteristics. To ensure stable tracking response, two sensors are required in conventional popular MPPTs. In modularized PV system as an AC module system, the cost of a sensor can have an effect on entire system cost because a power conditioning device is connected in a PV module. Because only a current sensor is required for proposed MPPT, it is helpful in the cost reduction point of view. In this paper, a novel MPPT using current sensor is proposed In the proposed MPPT, the voltage is derived from sensed current value. The proposed method is verified by simulation results.

• 조명전기설비학회논문지
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• 제25권1호
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• pp.59-63
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• 2011

In small-power applications, variable-speed motors having high efficiency and controllability become more dominant than brushed DC motors. BLDC motors with permanent magnets in the rotor and SRMs directed by reluctance torque due to no permanent magnets have been strongly studied as a candidate. Compared to the BLDC motors, SRMs are more suitable for low-cost applications since the magnetic structure is simple, mechanically robust, and cheap due to no additional excitation in the rotor such as copper wire, aluminum, and permanent magnets. In addition, relatively small number of phases in single and two-phase SRMs allows more cost savings with regards to material in the motor and switching devices in the converter. In this paper, several 2 phase SRMs are compared to a 3 phase 6/4 SRM in terms of flux distribution in key parts of the motors.

• 조명전기설비학회논문지
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• 제27권11호
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• pp.7-13
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• 2013

There has been a need for the systematic evaluation of the economic efficiency between conventional fluorescent lamp lighting systems that have been used in tunnels and LED lighting systems. This study has evaluated basic tunnel lighting between the conventional fluorescent lighting systems and the LED lighting system using the evaluation tool of tunnel lighting by Life Cycle Cost (LCC) and using the economic efficiency evaluation method. In addition, the unit discount rate of the LED lighting system and the estimated increase in the price of electricity have made the estimated cost of LCC the same if two luminaires were used in the basic part of the tunnel.

• 조명전기설비학회논문지
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• 제27권2호
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• pp.22-28
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• 2013

In this paper, the low cost SOA Dimming Driver which consisted of LabVIEW programming part capable of current pattern design, DAQ module for analog voltage output, and voltage to current converter has realized. The output current(possible to 3A) from the Driver was clearly constant without ripple and also showed no variance until 1mA unit for a long time operation. The proposed low cost Driver can replace the previous high cost SOA Drivers for wavelength swept lasers fully and provide the convenience and safety of auto-supplying a designed current pattern.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.65-67
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• 2008

일본 홋카이도 도야코에서 2008년 7월 열린 주요 8개국(G8) 정상회의에서는 2050년까지 전 세계 온실가스 배출량을 절반으로 줄이는 장기 목표론 추진하기로 했다. 본 논문은 D 발전소의 중유 연소에 따른 비용과 LNG 연소에 따른 비용이 같아지는 ton 당 $CO_2$ 배출비용을 찾고자 한다.

• 조명전기설비학회논문지
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• 제28권7호
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• pp.34-40
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• 2014

In this paper, we want to know the optimal replacement cycle(time) for this study was performed. The optimal preventive replacement age can be fond by finding the value of time that minimizes the cost function(model of Barlow and Jardine). In addition, The reliability of the relay according to the service environment were studied. The use of the exchange relay period is longer, and maintenance cost rate(per hour) may increase, and also the reliability may cause a decline. In addition, considering the preventive maintenance and purchase order, a representative relay(RAX-L440-A type) life was calculated.