• 전기학회논문지
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• 제66권2호
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• pp.300-304
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• 2017

Due to the introduction of various types of dispersed generations (DGs) with larger capacity in a power distribution system, the short-circuit current is expected to be increased, which more requires for the effective fault current limiting methods. As one of the promising countermeasures, the superconducting fault current limiter (SFCL) has been noticed. However, the decreased fault current by SFCL affects the operation of the overcurrent relay (OCR), representative protective device in a power distribution system. In this paper, the operation of the overcurrent relay due to the application of a SFCL in a power distribution system with DG linked by its bus line was analysed through the short-circuit tests. To analyze the effect of the SFCL application in a power distribution system with DG, the experimental simulated circuits were designed and the short-circuit tests for the power distributed system assembled with the DG, the OCR and the SFCL were carried out. Through the analysis on the short-circuit tests, the application of the SFCL in a power distribution system with DG could be confirmed to be contributed to the operational improvement of overcurrent relay.

• 전기학회논문지
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• 제63권8호
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• pp.1064-1069
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• 2014

The railway signalling system plays an essential role in the headway and routing control for a safe and efficient train operation. The reliable and safe operation of the system is very important because the failure of the railway signalling system can lead to the collision, derailment, or unexpected stop of a train. So far, the conventional wayside signal mode (ATS: Automatic Train Stop) has been generally used as the railway signalling system. However, this system is highly linked to a risk of major accidents resulted from human mistakes such as missing a signal or careless control of train speed. Accordingly, the onboard signal mode (ATC: Automatic Train Control) as an alternative of ATS has been recently introduced and applied to transmit effectively the information on speed control of a train by using computers and communication equipment. In the process of replacing the obsolete signal system, it is necessary to switch over the system while providing passengers with normal services. Therefore, the integration of a railway signaling system compatible for both ATS and ATC and its interface is discussed in this study. In particular, the implementation scenario required for operation planning of the integrated system was designed, and the results as well as effects of its applicability test were also presented.

• Journal of Information Display
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• 제6권2호
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• pp.16-18
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• 2005

Hybrid insulator pentacene thin film transistors (TFTs) are fabricated with thermally grown oxide and cross-linked polyvinylalcohol (PVA) including surface treatment by dilute ploymethylmethacrylate (PMMA) layer on $n^+$ doped silicon wafer. Through the optimization of $SiO_2$ layer thickness in hybrid insulator structure, carrier mobility is increased to more than 35 times than that of the TFT which has only a gate insulator of $SiO_2$ at the same electric field. The carrier mobility of $1.80cm^2$/V-s, subthreshold swing of 1.81 V/decade, and $I_{on}/I_{off}$ current ratio> $1.10{\times}10^5$ are obtained less than -30 V bias condition. The result is one of the best reported performances of pentacene TFTs with hybrid insulator including cross-linked PVA layer as a gate insulator at relatively low voltage operation.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1291-1293
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• 2005

Hybrid insulator pentacene thin film transistors (TFTs) were fabricated with thermally grown oxide and cross-linked polyvinylalcohol (PVA) including surface treatment by dilute ploymethylmethacrylate (PMMA) layers on $n^+$ doped silicon wafer. Through the optimization of $SiO_2$ layer thickness in hybrid insulator structure, carrier mobility was increased to above 35 times than that of the TFT only with the gate insulator of $SiO_2$ at the same transverse electric field. The carrier mobility of 1.80 $cm^2$/V-s, subthreshold swing of 1.81 V/decade, and $I_{on}$/ $I_{off}$ current ratio > 1.10 × $10^5$ were obtained at low bias (less than -30 V) condition. The result is one of the best reported performances of pentacne TFTs with hybrid insulator including cross-linked PVA material at low voltage operation.

• 한국물환경학회지
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• 제30권1호
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• pp.31-43
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• 2014

Recently, Andong Reservoir and Imha Reservoir located in Nakdong River basin (Korea) are being connected by a tunnel (length 2km, diameter 5.5m) for a conjunctive use. The objectives of this study were to construct a two dimensional(2D) laterally-averaged model for two reservoirs, and examine the effects of connection on the water transportation and temperature stratification in the reservoirs. The 2D models for each reservoir were calibrated using field data obtained in 2006, and applied to the linked system for the year of 2002 when a severe flood intruded into Imha Reservoir during the typhoon Rusa. Simulation results showed that 364 million $m^3$ of water can be conveyed from Imha to Andong, while 291 million $m^3$ of water from Andong to Imha after connection. It resulted in 1.38 m increase of annual averaged water level in Andong Reservoir, whereas 3.75 m decrease in Imha Reservoir. The structures of thermal stratification in both reservoirs were influenced in line with the flow exchanges. In Andong Reservoir, the location of thermocline moved upward about 10 m compared to an independent operation. The results imply that the persistent turbidity issue of Imha Reservoir might be shifted to Andong Reservoir during a severe flood event after connection.

• 설비공학논문집
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• 제24권11호
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• pp.813-822
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• 2012

In this study, the multizone simulation for biosafety of BSL3 lab. and energy simulation are carried out simultaneously by using linked model of CONTAM and TRNSYS. In BSL3 lab., annual energy consumption is approximately five to ten times more than the magnitude of the office building. This is because required air change rate is extremely large and it is difficult to maintain room pressure difference efficiently. To maintain pressure difference between laboratory rooms through sealing condition of doors and proper airflow control is significant. In this study, to predict indoor environment of the BSL3 lab.(Influenza A research lab.), the multizone simulation for four kinds of biohazard scenario is also performed as part of risk assessment. Multizone and energy simulation results by using linked model show that these approaches are used as a tool for the energy efficient design and operation method for the safer BSL3 lab. facilities.

• Nuclear Engineering and Technology
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• 제41권4호
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• pp.549-560
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• 2009

Over the last three decades, nuclear technology development has played a vital role in the socio-economic development of the Republic of Korea. This study, being the first of its kind, focuses on quantifying the actual economic contribution of nuclear technologies to economic development by evaluating the net benefit of the nuclear power with respect to the country's Gross Domestic Product (GDP). An input-output analysis was employed as a methodological approach to analyze inter-industrial economic activities by calculating the industrial value added as a means of the economic contribution during the period of 1980 to 2005. The industrial value added of nuclear technologies was estimated from the construction and operation of nuclear power (backward-linked industrial value added) and from the industrial activities attributed to the electricity generated by the nuclear power (forward-linked industrial value added). It was found that the total net contribution of nuclear technologies as a percentage share of GDP amounted to 2.38% in 2005.

• 설비공학논문집
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• 제24권2호
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• pp.183-189
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• 2012

Most of the domestic residential buildings have used the traditional radiant heating system, circulating hot water through the cross-linked polyethylene(PE-X) pipe buried in the floor panel of the heating space. New type of the heating panel was recently developed using heat pipes with double wicks. Some experiments were carried out in this study to verify the thermal characteristics of this heating system at the unit heating space which surrounded by outer space whose temperature of air be maintained scheduled value with time. Through the various experiments with several parameters, such as flow rate, inlet and outlet temperatures of hot water and the heating duration and so on, we found that the floor heating system with heat pipes was able to reduce the pumping power for hot water circulation by 4~31% compared with the conventional panel heating system using PE-X pipe. These results could be used for optimal design and efficient operation of the heating system as well as improvement of thermal comfort.

• 한국안전학회지
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• 제38권2호
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• pp.81-86
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• 2023

In this study, a one-dimensional numerical model was constructed to propose a flood control plan linked with the dam and river basin for the flood events of the Seomjin River in 2020. The flood level reduction of the downstream river was tested based on a scenario operation of the Seomjingang Dam and was also analyzed when a storage pocket was newly constructed as one of the river basin measures. It was confirmed that Seomjingang Dam's flood control capacity would be increased if the flood limit level was drastically lowered from the current EL. 196.5 m to EL. 188.0 m. In addition, if the upper area of the (old) Geumgok Bridge (which suffered great damage due to the loss of the levee) is used as a storage pocket, it would be effective in preventing floods in the lower area of it. In the era of the climate crisis, more integrated flood management is needed and basic river management must be observed.

• 벤처창업연구
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• 제7권2호
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• pp.9-17
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• 2012

다양한 유형의 공공기관과 교육기관에서 창업지원사업을 시행 중이다. 본 연구는 창업교육을 중심으로 각 기관과 단체에서 실행하고 있는 창업지원사업을 연계함으로써 지원성과 제고효과가 있음을 제시한다. 창업지원사업의 목적을 달성하기 위해서 요구되는 것은 창업이전단계부터 창업초기를 거쳐 죽음의 계곡이라 불리는 시점을 극복한 후 성장기업으로 안정화 되는 기간까지, 전체과정에 대한 일관되면서도 효과적인 지원이다. 현재까지 이루어진 대부분 선행연구에서 창업교육 후 사후관리의 필요성을 제시하고 있다. 그러나 교육 후 사후관리의 현실적 방안제시에는 한계를 보이고 있다. 이러한 한계점은 창업교육을 창업전과정의 한 부분으로 분리해서 접근하는 인식에서 발생한다. 이와 같이 분리된 접근 방식은 창업과 관련된 다양한 지원정책의 현실적인 공통점으로 보인다. 본 연구는 창업교육과 창업관련 지원의 연계에서 발생하는 기대효과를 제시하고, 지원정책들과 창업교육의 연계방안으로 창업인증제도의 필요성을 제기한다.