• Journal of Korean Society of Disaster and Security
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• v.16 no.1
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• pp.71-80
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• 2023

Fuel cells are low-carbon power sources that can expand distributed energy system and electric vehicle charging infrastructure when installing fuel cells in gas stations. In order to ensure safety for fuel cells in gas stations, quantitative risk assessments were conducted after deriving accident scenarios based on accident data of domestic and foreign gas stations and fuel cells. It calculates the expected extent of damage from fire and explosion that can occur in reality, not the worst accident scenario, and analyzes the damage impact. The separation distance of more than 9.0 m from a dispenser, 15.5 m from a car under refueling, 4.1 m from the ventilation pipe, 1.1 m from the gas adjustment device prevent the severe damage caused by the expected accident. This study result can be used to deploy fuel cells in gas stations and establish safety measures.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.93-102
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• 2023

This study investigated the possibility of treating heavy metal pollutants existing in the air in addition to simultaneously removing NOx and SOx by injecting oxidizing and reducing agents into a scrubber into a microbubble device to create an eco-friendly method that does not generate secondary pollutants. Lead compound (Pb) was selected as the heavy metal substance in the air to be treated with microbubbles, and the removal efficiency was confirmed. By treating microbubbles by connecting them to a scrubber, it was confirmed that not only NOx and SOx but also heavy metal substances in the air were reduced, cost was reduced, and secondary environmental pollutants were not generated. Through this study, it was possible to simultaneously remove NOx, SOx, and heavy metals at low cost by applying an eco-friendly method, rather than the existing high-cost treatment method such as SCR. If oxidizing agent, reducing agent, and microbubbles are used appropriately, economical and efficient air pollution can be achieved. Since material processing was possible, it is expected to be helpful in the technological development of environmental prevention facilities.

• Journal of Korean Port Research
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• v.12 no.1
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• pp.55-64
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• 1998

Directed graphic algorithm was applied to an empirical analysis of traffic occupant fatalities based on a model by Crandall. In this paper, Crandall's data on U.S. traffic fatalities for the period 1947-1981 are focused and extended to include 1982-1993. Based on the 1947-1981 annual data, the directed graph algorithms reveal that occupant traffic deaths are directly caused by income, vehicle miles, and safety devices. Vehicle mileage is caused by income and rural driving. The estimation is conducted using three stage least squares regression. Those results show a difference between the traditional regression methodology and causal graphical analysis. It is also found that forecasts from the directed graph based model outperform forecasts from the regression-based models, in terms of mean squared forecasts error. Furthermore, it is demonstrates that there exists some latent variables between all explanatory variables and occupant deaths.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.5
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• pp.52-62
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• 2022

A launch vehicle is a one of the biggest hardware among the products of human technology. For huge size launch vehicles, to transport to Launch Complex and to erect on launch pad precisely and safely is very critical issue. Therefore, a final assembly, transportation, erection and holding in vertical position in launch pad requires very precise operational technology, processes and related aggregates. Those operational concept has been developed to comply with the requirement of each launch vehicle and technology level at that time. In this paper, a progress of operational methodology in global launch vehicles are described. In addition, methodologies used on the KSLV-1 Naro and the KSLV-II Nuri launch vehicle are introduced.

• Journal of the Korea Society of Computer and Information
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• v.14 no.1
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• pp.183-190
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• 2009

The core technique of ubiquitous computing is the context aware computing and the context aware technique is more like software so the important research work is to develop the core engines first and the adapted device for the engines. When ubiquitous computing era comes, the current existing internet shopping mall, the form of searching the direct goods and ordering the goods by the customers evolves and develops the form of system that recommends the goods by the search engine which combined with the input data and technique of case based reasoning and intelligent agent that is based on the context aware technique. In this paper, search engine which is based on the case based reasoning and intelligent agent is designed and the prototype is implemented to be adapted to the internet fashion expert shopping mall.

• The Journal of the Acoustical Society of Korea
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• v.41 no.6
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• pp.669-679
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• 2022

Lithium-ion battery has been used for lots of electronic devices. With the popularization of batteries, researchers have focused on batteries' electrochemical performances by environmental conditions, such as temperature, vibration, shock and charging state. Meanwhile, due to very serious global warming, car companies have started using lithium-ion batteries even in cars, replacing internal combustion engines. However, batteries have been developed based on non-moving systems which is totally different from vehicles. In the line of the differences, researchers have tried to reveal relationship between variables from dynamic systems and batteries. In this review, we discuss the comprehensive effect of vibration and shock on batteries. We firstly summarize vibration profiles and effect of normal vibration on batteries. We also sum up effect of shock and penetration on batteries and introduce how ultrasound influences on batteries. Lastly, outlook for the battery design as well as dynamic design of EVs are discussed.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.7
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• pp.935-944
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• 2017

As augmented reality technology has developed, various augmented reality contents can be seen in real life, and the performance of mobile device is improved, so augmented reality technology can be used even without special device. As a result, a training system, guidance system and a museum art guide system based on augmented reality technology are emerging, and interest in augmented reality is also increasing. However, the existing guidance systems using a single mobile device have limitations in terms of the user experience (UX) because the camera of the device limits the field of view or the two hands are not free and the user input is difficult. In this paper, we compare augmented reality based guidance systems for Rubik's Cube using tablet and HMD to improve the constraint of user experience of such a single mobile device, and find elements that positively improve user experience. After that, we evaluate whether the user experience is actually improved through the user experience comparison test and the questionnaire.

• 한국벤처창업학회:학술대회논문집
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• 2020.11a
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• pp.69-80
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• 2020

본 연구는 국내 기업의 대다수를 차지하고 있는 중소기업 중 기술과 연관성이 깊은 제조 분야의 종사자를 대상으로 기업과정신과 개인적 특성에 대한 핵심요인이 창업 의도에 미치는 영향을 조사해보았다. 특히 기업가정신의 핵심요인과 개인적 특성이 기회역량을 매개로 하였을 때 창업의도에 어떠한 유의미한 연관성을 설명해 줄 것인지 그리고 창업의도에 공기업의 기술개발지원사업(R&D)이 어떠한 조절적 영향을 미치는지에 대해 알아보고 제조분야 중소기업 창업 활성화를 위한 정부의 정책 설정에 시사점을 제공할 목적으로 수행하였다. 이를 위해 장치산업과 관련된 제조분야 중소기업 종사자 292명을 대상으로 2020년 5월 설문 조사를 통해 자료를 수집하였고, 각종 통계분석과 방정식을 통해 자료를 분석하였다. 기업가정신의 핵심요인 중 진취성과 개인적 특성 중 하나인 내재적 통제 요인이 반복적으로 결과에 영향을 미치지 못하였는데, 이는 실제 창업 이전단계에서 나타날 수 있는 특성으로 구분할 수 있으며, 혁신성 또한 창업 전, 후로 구분하여 연구해야 할 필요성을 확인하였다. 연구의 결과를 정리하면 다음과 같다. 첫째, 기업가정신의 핵심변수인 혁신성, 진취성, 위험감수성 중 진취성을 제외한 요인이 기회역량에 영향을 미치며, 개인적 특성의 하위변수인 자기효능감, 내재적 통제, 모호성에 대한 인내 중 내재적 통제 요인만이 기회역량에 영향을 미치지 못하였다. 둘째, 기회역량의 하위변수인 기회인식과 평가는 모두 창업의도에 영향을 미치는 것으로 나타났다. 셋째, 기업가정신과 개인적 특성에 대한 하위요인과 창업의도 사이에서 기회역량의 매개 여부를 조사하였는데, 진취성과 내재적 통제 요인이 기각되었으며, 혁신성은 기회역량 중 기회인식만이 매개하는 것으로 나타났다. 마지막으로 공기업의 기술개발지원사업(R&D)이 창업의도를 조절하는데 유의미한 역할을 하는 것으로 나타났다. 이를 종합하면 기업가정신과 개인적 특성은 실제로 창업이 일어나는 전, 후로 구분하여 창업의도에 미치는 영향에 관한 연구가 진행되어야 한다는 점을 보여주고 있으며, 제조분야의 창업 활성화를 위한 정책을 수립하는 데 있어 효과적인 자료로 활용될 수 있는데 본 연구가 기여하는 바가 크다고 할 수 있다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.6
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• pp.37-42
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• 2022

Recently, with the development of mobile communication technologies such as 5G, interest in oscilloscope technology based on high bandwidth and user-friendly UI is increasing. In this paper, we proposed a Python-based UI(user interface) SW for a high-bandwidth digital oscilloscope in connection with the study of a 13GHz band digital oscilloscope system. The proposed UI SW is designed not only to be executed integrally with the oscilloscope, but also to be run on a separate PC or laptop cooperating with the instrument through WiFi communication. Functions of the UI SW consists of displaying and analyzing signal data, storing signal data in an external storage device, generating test signal data, and reconfiguring the toolbar. Finally, we have shown that the proposed digital oscilloscope system operates normally by interworking test with the signal generator.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.237-237
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• 2020

수도계량기(이하 "수량계")는 액체용 적산부피계로 물 사용량을 적산 계량하기 위한 기계기구 또는 장치이며 수량계 검정기준에 의해 검사기준 합격제품을 사용하서 수도요금을 징수합니다. 사실상 국내계량에 관한 법률에 의거하여 전이유량비가 6.3배수(2014년) > 4.0배수(2016년) > 1.6배수(2017년)로 점점 향상되며 2017년 기준으로 국제법정계량기구(OIML)의 성능과 같은 1.6배수까지 향상되어 국내의 수량계 기술기준이 많은 부분 향상되었습니다. 그러나 국제법정계량기구(OIML)는 현재 1.6배수의 80배수까지 검사기준에 합격에 반하여 현제 국내의 검사기준은 1.6배수의 100배수까지만 합격기준을 가지고 있습니다. 이러한 기준은 점차 발전해가고 있는 후발국가에 속하는 자국의 검사기준이 너무 갑작스럽게 국제법정계량기구(OIML)의 기준보다 높은 검사기준을 시행하며 많은 문제가 발생한 것 같습니다. 위와 같은 문제를 해결하기 위하여 여러 복합적인 부품으로 이루어진 수량계의 유량 및 유속에 영향력이 있다고 보여지는 특정 부품 혹은 부위의 개선 및 개발로 해결할 수 있지 않을까 하는 의구심에 연구를 시작되었습니다. 유량 및 유속에 영향을 끼치는 유입부의 스트레이너, 내부 임펠러의 변경으로 성능검사에서 영향을 끼치는지를 유체역학 및 유동해석 등을 통하여 테스트 후 각각 단계 및 상황별 목업금형을 제작하여 현재 국내검사기준으로 진행되는 성능테스트인 기차테스트를 진행하였습니다. 먼저 수량계의 특성상 수량계 내부의 유량을 유체역학 및 유동해석으로 정확히 뽑아내는 것이 불가능하여 유입부 유출부의 유량의 흐름을 기준으로 유체역학 및 유동해석을 진행하였습니다. 테스트 후 그 결과 값으로 유입부의 스트레이너의 삽입 각도를 0°, 90°, 135°, 180°, 270°로 각각 제작하여 테스트를 진행하였으며, 내부 임펠러는 straight, SR, SL, SL R70, SL R60, R75, SR R65 형상으로 각각 제작하여 테스트를 진행하였습니다. 전반적으로 기존의 수량계보다 높은 성능을 보여주었으며, 특정 스트레이너의 삽입각도 및 임펠러의 형상에서는 기존보다 훨씬 유수율이 절감되는 결과값이 나왔습니다. 그로 인해 검사기준에 쉽게 부합할 수 있으며 물 사용량을 보다 정확히 계측하여 정확한 수도요금을 부과하여 국세 낭비로 인한 경제적 손실을 감소할 수 있을 것 같습니다.