• Transactions of the Korean hydrogen and new energy society
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• v.23 no.4
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• pp.323-329
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• 2012

A thermal management system of a proton exchange membrane fuel cell is taken charge of controlling the temperature of fuel cell stack by rejection of electrochemically reacted heat. Two major components of thermal management system are heat exchanger and pump which determines required amount of heat. Since the performance and durability of PEMFC system is sensitive to the operating temperature and temperature distribution inside the stack, it is necessary to control the thermal management system properly under guidance of operating strategy. The control study of the thermal management system is able to be boosted up with hardware in the loop simulation which directly connects the plant simulation with real hardware components. In this study, the plant simulation of fuel cell stack has been developed and the simulation model is connected with virtual data acquisition system. And HIL simulator has been developed to control the coolant supply system for the study of PEMFC thermal management system. The virtual data acquisition system and the HIL simulator are developed under LabVIEWTM Platform and the Simulation interface toolkit integrates the fuel cell plant simulator with the virtual DAQ display and HIL simulator.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04a
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• pp.661-663
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• 2001

EJB 표준 서버측 컴퍼넌트 표준 모델로서 객체지향 분산 애플리케이션의 개발 및 분산 배치를 위한 컴포넌트 아키텍처이다. EJB로 시스템을 구축시 프로그램의 개발을 쉽게 하고 단순화시키며 보안성, 영속성, 동시성, 트랜잭션 무결성, 보안 등의 처리를 자동으로 해주는 이점을 가진다. 또한 EJB 컴포넌트화 설계를 위해 디자인 패턴을 이용하면 설계 범위를 확장할 수 있고, 설계의 재사용성 효과를 높여주며, 설계 시간의 단축 및 의사소통에 대한 시간을 효과적으로 줄일 수 있다. 본 논문에서는 기존 시스템에서 데이터베이스 접근을 캡슐화하는데 이용하는 DAO의 트랜잭션 로직의 복잡성과 불필요한 DAO 생성 및 시스템 과부하의 문제점을 해결하고자 Integrated DAO 패턴을 제안한다. Integrated DAO 패턴은 컨테이너 관리 트랜잭션을 통해 트랜잭션 조작에 관한 복잡성을 줄여주기 때문에 시스템의 과부하 감소와 시스템 성능 향상에 효과가 있다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.725-731
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• 2016

This study numerically investigates the thermal performance of a 2.0-kW butane-based combustion heating system for an electric vehicle under cold conditions. The system is used for cabin space heating and coolant-based battery thermal management. ANSYS CFX 17 software was used for parametric analysis. The mass flow rates of cold air and coolant were varied, and their effects were compared. The numerical results were validated with theoretical studies, which showed an error of 0.15%. As the outside air mass flow rates were increased to 0.005, 0.01, and 0.015 kg/s, the cabin supply air temperature decreased continuously while the coolant outlet temperature increased. When the coolant mass flow rates were increased to 0.005, 0.01 and 0.015 kg/s, the air temperature increased while the coolant outlet temperatures decreased. The optimal mass flow rates are discussed in a consideration of the requirements for high cabin heating capacity and efficient battery thermal management.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.559-575
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• 2021

Due to the increase in ground excavation work, the possibility of ground subsidence accidents is increasing. And it is very difficult to prevent these risk fundamentally through institutional reinforcement such as the special law for underground safety management. As for the various cases of urban ground excavation practice, the ground subsidence behavior characteristics which is predicted using various information before excavation showed a considerable difference that could not be ignored compared to the results real construction data. Changes in site conditions such as seasonal differences in design and construction period, changes in construction methods depending on the site conditions and long-term construction suspension due to various reasons could be considered as the main causes. As the countermeasures, the safety management system through various construction information is introduced, but there is still no suitable system which can predict the effect of excavation and risk assessment. In this study, a web-based system was developed in order to predict the degree of impact on the ground subsidence and surrounding structures in advance before ground excavation and evaluate the risk in the design and construction of urban ground excavation projects. A system was built using time series analysis technique that can predict the current and future behavior characteristics such as ground water level and settlement based on past field construction records with field monitoring data. It was presented as a geotechnical data visualization (GDV) technology for risk reduction and disaster management based on web-based system, Using this newly developed web-based assessment system, it is possible to predict ground excavation impact prediction and risk assessment.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.582-589
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• 2011

The fuel cell technology has been considered as a technology to reduce greenhouse gases emission from a ship. In this research, internal reforming 500kW solid oxide fuel cell system fueled by methane for a ship were developed. Characteristics of gas temperature, stack power and system efficiency depending on the air flow rate, $CH_4$ flow rate, $H_2O$ flow rate, and system operation pressure are evaluated. As a result, air and $CH_4$ flow rate directly affect the temperature of inlet and outlet gas in the fuel cell stack. When the air and $H_2O$ flow rate increase, the stack power and system efficiency increases. However, the case of $CH_4$ flow rate increase, the efficiency decreases.

• Journal of the Korea Society of Computer and Information
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• v.25 no.12
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• pp.261-270
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• 2020

In this study, we identify promising technologies for Piggyback transportation system by analyzing the relevant patent information. In order for this, we first develop the patent database by extracting relevant technology keywords from the pioneering research papers for the Piggyback flactcar system. We then employed textmining to identify the frequently referred words from the patent database, and using these words, we applied the LDA (Latent Dirichlet Allocation) algorithm in order to identify "topics" that are corresponding to "key" technologies for the Piggyback system. Finally, we employ the ARIMA model to forecast the trends of these "key" technologies for technology forecasting, and identify the promising technologies for the Piggyback system. with keyword search method the patent analysis. The results show that data-driven integrated management system, operation planning system and special cargo (especially fluid and gas) handling/storage technologies are identified to be the "key" promising technolgies for the future of the Piggyback system, and data reception/analysis techniques must be developed in order to improve the system performance. The proposed procedure and analysis method provides useful insights to develop the R&D strategy and the technology roadmap for the Piggyback system.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.2
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• pp.151-159
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• 2017

A deep geological disposal at a depth of 500 m in stable host rock is considered to be the safest method with current technologies for disposal of spent fuels classified as high-level radioactive waste. The most important requirement is that the temperature of the bentonite buffer, which is a component of the engineered barrier, should not exceed $100^{\circ}C$. In Korea, the amount of spent fuel generated by nuclear power generation, which accounts for about 30% of the total electricity, is continuously increasing and accumulating. Accordingly, the area required to dispose of it is also increasing. In this study, various duplex disposal concepts were derived for the purpose of improving the disposal efficiency by reducing the disposal area. Based on these concepts, thermal analyses were carried out to confirm whether the critical disposal system requirements were met, and the thermal stability of the disposal system was evaluated by analyzing the results. The results showed that upward 75 m or downward 75 m apart from the reference disposal system location of 500 m depth would qualify for the double layered disposal concept. The results of this study can be applied to the establishment of spent fuel management policy and the design of practical commercial disposal system. Detailed analyses with data of a real disposal site are necessary.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.346-348
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• 2014

VTS 관제사의 가장 기본적인 업무는 모니터링과 동시다발적으로 발생하는 사건을 처리하는 업무라고 할 수 있다. 이러한 모니터링 업무와 동시발생 업무의 관리의 소홀 또는 실패가 VTS 관련 사고로 이어지는 경우가 많다, 그러함에도 불구하고 지금까지는 이 분야에 대한 연구가 부족하였다. 본고에서는 VTS 모니터링 업무와 동시발생 업무 관리의 특성을 분석하고 특히 방해와 산만을 일으키는 요소들을 집중적으로 검토하고 이것이 관제사의 역량에 미치는 영향을 알아보았다. 또한 이러한 문제의 해결책으로 미래계획기억과 분산 기억 시스템 이론을 적용하여 실질적으로 관제사 업무에 도움을 줄 수 있는 방법을 모색하였다. 또한 e-Navigation 과 관련하여 VTS 장비에 장착하여 관제사의 모니터링 업무와 동시다발 발생 업무 관리를 도울 수 있는 도구 개발에 대한 아이디어를 제안하였다.

• Journal of Korea Ship Safrty Technology Authority
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• s.31
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• pp.49-59
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• 2011

17,508개의 도서로 이루어진 군도국가 인도네시아의 지리적 기후적 특징을 소개하고 그와 관련된 현지 인도네시아의 해사안전체계 현황과 실태를 설명하고 있다. 최근 인도네시아 정부는 호주 및 일본과의 해상운송분야의 안전성 제고를 위한 국제협력사업을 수행중이거나 수행하였으나 아직까지 해사안전관리 체계가 국제적 표준에 미치지 못하는 실정임에 따라 이를 보완하기 위한 노력의 일환으로 IMO협약 비준을 통한 해사안전규정의 강화와 아울러 Navigation Aids 설치 확대 및 전자해도개발 등 해사안전관리체계의 선진화를 시도함과 동시에 선진국을 상대로 자금지원과 선진화된 기술이전을 위한 국제협력의 문을 개방하고 있다. 이에 부응하여 조선 및 해운분야의 선진국인 우리나라가 인도네시아 정부와 해사안전분야의 활발한 국제협력을 통하여 우리나라 조선 및 관련 기자재 산업의 인도네시아 진출을 위한 새로운 계기를 만들어야 할 것이다.

• Journal of Korean Society of Archives and Records Management
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• v.6 no.2
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• pp.5-25
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• 2006

In this study, twelve research papers on "records management and archives research areas" that were written from the 1980s to the 2000s were analyzed according to a timeline. The results show that the main subject areas during the 1980's were records and archives. During the 1990s, with the increase of electronic records, research areas expanded to information systems and related social environments. In the 2000s, more advanced technical and interdisciplinary subjects have emerged in the digital society. These results show that research areas in records management and archives still have much potential for growth and will expand in the near future.