• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.2
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• pp.79-95
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• 2022

Since space exploration began in the 1950s, numerous upper stage engines have been developed and used based on various design concepts. In this paper, information of upper stage engines which developed or developing is analysed and their characteristics and performance are summarized. These days, there are many cases of commercial heavy launch vehicles applying upper stage engines using liquid hydrogen with expander cycle which launched recently. Engines operating by Kerosene seem to be close to its theoretical maximum performance based on past experiences. Meanwhile, engines using methane propellant, which has recently become an issue, are also undergoing many developments because of various advantages. Recently, private companies are actively participating in launch vehicle market, and there are many cases in which the government and companies jointly research of next-generation engine.

• Journal of Korea Port Economic Association
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• v.39 no.1
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• pp.17-34
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• 2023

The maritime industry is undergoing significant changes due to digitalization and decarbonization, collectively known as "2D." This study investigates how these transformations are impacting the industry's business models. Since the changes are still ongoing, a cognitive approach was used to derive business models, rather than relying on actual case studies. The study presents experimental maritime business models that correspond to the four types of business model frameworks (or archetypes), along with recent trends for each model. The research results show that new business models are emerging in various areas, including the commercial and technical fields of the maritime industry. This thought-provoking study is significant as a pioneering investigation that will stimulate subsequent case-based research in academia and provide strategic guidance to market participants or policy makers in the maritime industry.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.72-72
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• 2020

전 세계 태양광 발전용량은 2010년 초 25GW에서 2019년 말 617.9GW로, 지난 10년 동안 25배 이상 증가하였다(2019년 전세계 태양광 발전(PV)의 추가량은 거의 133GW 추정). 2020년에도 세계 태양광시장은 120~150GW를 형성해 전년대비 10% 내외의 성장세를 이어갈 것으로 전망되며, 향후에도 성장률은 다소 낮아지겠지만 2030년 태양광 수요피크 200GW까지 지속적인 성장이 기대된다. 한편 우리나라 수상태양광은 높은 잠재력(저수면적의 7%를 활용할 경우 5,304MW 규모의 수상태양광 개발이 가능)을 가지고 있는 것으로 평가된다. 신(新)정부 국정과제 3020 신재생 확산정책에 따라 신재생에너지 보급률 확산이 전망되는 가운데, K-water의 중장기('17~'26) 전략경영계획에 따르면 수상태양광은 2026년까지 2,758MW 개발을 목표로 하고 있다. 하지만, 수상태양광은 경제성과 환경적 측면에서의 불확실성을 포함하여 시설물의 안정성 검증, 사회적 수용성 등 극복해야 할 정책과제들을 안고 있다. ① REC 가격의 안정화, 경제성 제고 문제(높은 운영 및 관리 비용), ② 난개발, 환경·경관·안전 문제에 대한 주민들의 우려 : 주민 수용성 제고, ③ 투자 사기와 유착·비리, 편법개발, 난개발에 대한 규제방안, ④ 지역사회와의 거버넌스 및 갈등관리 문제, 공용 전력망 부족과 계통연계 문제 등. 이에 본 연구는 태양광 선도국가의 정책 사례 분석을 통해 수상태양광 관련 명확한 규제 및 지원정책을 제언하고자 한다. 분석방법으로는 첫째, 주요 국가에서 시행 중인 수상태양광에 대한 금융지원 및 정책 지원을 국내 사례와 비교·분석하였으며 둘째, 경제적·생태적 관점에서 수상태양광 모델을 개발하고, 이를 지역사회가 수용할 수 있도록 정책적 대안을 제시하였다.

• Annual Conference on Human and Language Technology
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• 2019.10a
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• pp.510-513
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• 2019

감정분석은 텍스트에서 나타난 저자 혹은 발화자의 태도, 의견 등과 같은 주관적인 정보를 추출하는 기술이며, 여론 분석, 시장 동향 분석 등 다양한 분야에 두루 사용된다. 감정분석 방법은 사전 기반 방법, 기계학습 기반 방법 등이 있다. 본 논문은 사전 기반 감정분석에 필요한 한국어 감정사전 자동 구축 방법을 제안한다. 본 논문은 영어 감정사전으로부터 한국어 감정사전을 자동으로 구축하는 방법이며, 크게 세 단계로 구성된다. 첫 번째는 한영 병렬 말뭉치를 이용한 한영 이중언어 사전을 구축하는 단계이고, 두 번째는 한영 이중언어 사전을 통한 한영 이중언어 그래프를 생성하는 단계이며, 세 번째는 영어 단어의 감정값을 한국어 BPE의 감정값으로 전파하는 단계이다. 본 논문에서는 제안된 방법의 유효성을 보이기 위해 사전 기반 한국어 감정분석 시스템을 구축하여 평가하였으며, 그 결과 제안된 방법이 합리적인 방법임을 확인할 수 있었으며 향후 연구를 통해 개선한다면 질 좋은 한국어 감정사전을 효과적인 방법으로 구축할 수 있을 것이다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4D
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• pp.493-504
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• 2008

Considerable effort has been made to improve construction processes through mechanization and robotization of current work. In this paper, the trend of research and development related to the construction machinery automation to improve the construction productivity has been reviewed. A classification system is proposed for automation of architectural and civil works. Then, the priority among the classified construction tasks for automation has been identified through the questionnaire study. Based on the priority for automation a comprehensive technology road map was also developed. The technology road map suggests the time frame to complete R&D work for the selected construction tasks and the core technology required for automation of the selected tasks. Such automation R&D road map for construction machinery can be utilized as a milestone in setting up the R&D strategy in the construction industry.

• Journal of Practical Agriculture & Fisheries Research
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• v.26 no.1
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• pp.5-15
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• 2024

China is the largest producer and consumer of mushrooms, and the development of China's mushroom industry poses a serious threat to Korea, which has similar mushroom production and consumption tendencies. China's mushroom industry produced only 50,000 tons around 1985 when statistical data began to be published, but by 2020, it has developed into an industry with annual production exceeding 40 million tons. The rapid development of the mushroom industry in China is due to high profitability, rapid funds turnover, rapid return on investment, active support from local governments, increased preference and consumption of healthy foods due to increased national income, expansion of overseas exports, and introduction of automated facility cultivation. Recently, there is a high possibility that mushroom production through automated facility cultivation in China will be excessive, so if measures are not taken, there is a high possibility that it will encroach on the Korean mushroom market. Therefore, in order to protect domestic mushroom farmers and industries, it is necessary to accurately identify and analyze the current status of China's mushroom industry.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.68-76
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• 2024

With the recent rapid growth of the domestic and international unmanned aerial vehicle (UAV) market and the increasing importance of UAV operations in urban centers, such as UAMs, the safety management and regulatory framework for human life and property damage caused by UAV failures has been emphasized. In this study, we conducted a comparative analysis of risk-cost models that evaluate the risk of an operating area for safe UAM flight path planning, and identified the main limitations of each model to derive considerations for future model development. By providing a basic model for improving the safety of UAM operations, this study is expected to make an important contribution to technical improvements and policy decisions in the field of UAM flight path planning.

• Membrane Journal
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• v.34 no.1
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• pp.1-9
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• 2024

The rapid expansion of the electric vehicle market has led to increased demand for battery recycling technologies. The recycling of spent batteries is crucial to stabilize the supply of rare metals, including lithium, cobalt and nickel, which are essential components for the battery industry. In addition, the technology for recycling spent batteries can help to reduce environmental and health impacts. This review presents the theoretical principles behind the metal recovery technology and the processes that are currently commercially available. It also describes trends in research and technological developments that aim to improve existing processes, and provides an overview of where recycling technology is headed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.554-564
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• 2017

The purpose of this study is to assist farmers in determining the optimal time for the shipment of stored apples by investigating the market trends, storage status and release dates of low-temperature stored apples. We surveyed 300 apple cultivation farms in Daegu, Gyeongbuk Province, which is the main producer of apples, and examined the cultivars, cultivation areas, storage conditions, and shipment status of apples. The main results are as follows: the proportion of apples cultivatedat different ripening times was surveyed. According to the results, the proportions of early, middle and late varieties were 78.3%, 63.7% and 96.0%, respectively. Also, 48.7% of the farm households surveyed had cold storage facilities. The average storage cost per apple box(15kg) was 978.3 won for self-storage and 1,771.8 won for consignment storage. For the six(6) months between November and April, the proportion of shipped apples was 91.6% of the total stored apples. The (average total?)annual apple shipment, including apples stored in general storage warehouses, was 744.4 boxes. The (average total?) annual shipment of cold storage apples was 616 boxes. The stored apples were mainly shipped to 'wholesale markets', which have the highest sales share, followed by 'production site collectors' and then 'supermarkets'. The most common shipping method of the apples was by general trucks, followed by low-temperature trucks, and finally by delivery services. The analysis of the factors influencing the decision to release apples by period showed that it was affected by the storage cost, loss rate, and customary shipping in the off-season(from May to August). On the other hand, in the general release season(from November to April), the statistically significant decision factors for the release of apples were the future expected price, storage cost and decision of the leading farmer groups. For farmers with a high share of general shipment, the deciding factors for the release of apples were the future expected price, storage cost, high income expectation, and decision by leading farmers.

• Korean Security Journal
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• no.21
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• pp.75-94
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• 2009

Since mechanical security systems are mostly composed of electronic, information and communication devices, they have effects in the aspects of overall social environment and crime-oriented environment. Also, the importance is increasing for wireless recognition of RFID and tracing function, which will be usefully utilized in controlling the incomings and outgoings of people/vehicles or allowance, surveillance and control. This is resulting from the increase in the care for the elderly according to the overall social environment, namely, the aging society, and the number of women entering, as well as the increase in the number of heinous crimes. The purpose of this study is to examine the theoretical considerations on ubiquitous sensor network and present a direction for securities companies for their development by focusing on the technological and application areas. To present strategies of response to a new environment for security companies, First, a diversification strategy is needed for security companies. The survival of only high level of security companies in accordance with the principle of liberal market competition will bring forth qualitative growth and competitiveness of security market. Second, active promotion by security companies is needed. It is no exaggeration to say that we are living in the modern society in the sea of advertisements and propaganda. The promotional activities that emphasize the areas of activity or importance of security need to be actively carried out using the mass media to change the aware of people regarding security companies, and they need to come up with a plan to simultaneously carry out the promotional activities that emphasize the public aspect of security by well utilizing the recent trend that the activities of security agents are being used as a topic in movies or TV dramas. Third, technically complementary establishment of ubiquitous sensor network and electronic tag is needed. Since they are used in mobile electronic tag services such as U-Home and U-Health Care, they are used throughout our lives by forming electronic tag environment within safe ubiquitous sensor network based on the existing privacy guideline for the support of mobile electronic tag terminal commercialization, reduction in communication and information usage costs, continuous technical development and strengthening of privacy protection, and the system of cooperation of academic-industrial-research needs to be established among the academic world and private research institutes for these parts.