• Journal of the Society of Naval Architects of Korea
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• v.58 no.4
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• pp.225-233
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• 2021

Conventional submarine propulsion batteries have mainly used lead acid batteries, which have proved relatively safe, but in recent years, research on mounting lithium-ion batteries to improve the underwater operation capability of submarines is underway in advanced countries such as Japan. Korea has world-class technology in the development of electric vehicles and lithium-ion batteries for energy storage, but fire safety accidents continue to occur in electric vehicles and energy storage lithium-ion batteries. In order to mount the lithium-ion battery in a submarine, it is necessary to check the safety as well as whether the performance is improved compared to the lead acid battery. Through the charge/discharge experiment of this lithium-ion battery module unit, it was possible to measure how much performance was improved compared to the lead acid battery. Safety tests were conducted on the lithium-ion battery module assuming that it was mounted on a submarine, and it was confirmed that safety was secured when applied to a submarine. Since many modules are mounted on actual submarines, it has been confirmed that it can be applied to submarine systems by simulating charge/discharge characteristics through Hardware-in-the Loop(HILS). Through the results of this study, the application of lithium-ion batteries to submarines is expected to significantly improve the sustainability of underwater operations.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1183-1194
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• 2021

Traditionally, electric power systems have been known as the centralized structures, which is organized into placing customers at the end of the supply chain. However, recent decades have witnessed the emergence of distributed energy resources(:DERs) such as rooftop solar, farming PV system, small wind turbines, battery energy storage systems and smart home appliances. With the emergence of distributed energy resources, the role of distributed system operators(:DSOs) will expand. The increasing penetration of DERs could lead to a less predictable and reverse flow of power in the system, which can affect the traditional planning and operation of distribution and transmission networks. This raises the need for a change in the role of the DSOs that have conventionally planned, maintained and managed networks and supply outages. The objective of this research is to designed the future distribution operation system with multi-DERs and the proposed distribution system model is implemented by hardware-in-the-loop simulation(HILS). The test results show the normal operation domain and reduction of distribution line loss.

• Journal of Korean Society of Transportation
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• v.33 no.1
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• pp.70-80
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• 2015

In recent years, tram has been the focus of a new mode of public transportation that can solve traffic jams and decrease public transit usage and environmental problem. This research is in the works to develop a tram signal controller and signal control strategies, and aim to resolve the problem of what could happen if a tram system was installed in general road. We developed the hierarchical signal control strategies to obtain a minimum tram bandwidth and to minimize vehicle delay, in order to perform a priority control to include passive and active signal priority control strategies. The strategies was produced for S/W and H/W, it is based in standard traffic signal controller. We conducted a micro simulation test to evaluate the hierarchical signal control strategies, which showed that the developed optimization model is effective to prevent a tram's stop in intersection, to reduce a tram's travel time and vehicle's delay.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.30 no.2
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• pp.37-45
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• 2012

Byeolseo was located in various places with beautiful natural scenery to avoid the mundane world and for country life in seclusion. In this study, to classify locational type and characteristics of Byeolseo in Gyeongsangnamdo and Jeollado areas, complex locational types and characteristics of total 96 Byeolseo (52 in Gyeongsangnamdo and 44 in Jeollado) were researched and cluster analysis was executed to group locational characteristics to several clusters with similar characteristics in order to classify locational types of Byeolseo. As the result, locational type for Gyeongangnam-do and Jeolla-do were classified to 5 types each. Unique locational types Gyeongsangnamdo were 'valley type' and 'cliff type' and unique ones for Jeollado were 'flatland type' and 'riverside.hill type'. 'Hill type', 'curvy river type' and 'riverside other type' were shown in both areas. In Gyeongangnamdo, 30.8% was cliff type and 15.4% was valley type 46.2% of the total was locatedon 'cliff near river' or 'valley'. These were the most popular locational characteristics of Gyeongangnamdo. Unlike Gyeongangnamdo, 18.2% was flatland type, 18.2% is riverside.hill type, and 39.6% was hill type in Jeollado 75.0% of the total was locatedon 'flatland', 'on hill near river' or 'on hils'. These were the most popular locational characteristics of Jeollado. Such locational characteristics showed that Byeolseo was located using nearby scenery considering topographic characteristics of the located area.