• Composites Research
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• v.19 no.4
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• pp.23-30
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• 2006

In the development of a cryogenic propellant tank, the proper selection of adhesives to bond composite and metal liner is important for the safety of operation. In this study, 3 types of adhesives were tested for the ability to bond CFRP composites developed for cryogenic use and aluminum alloy (Al 6061-T6) for lining the tank using double-lap joint specimens. The double-lap joint specimens were tested inside an environmental chamber at room temperature and cryogenic temperature ($-150^{\circ}C$) respectively to compare the bond strength of each adhesive and fracture characteristics. The material properties with temperature of component materials of double-lap joints were measured. In addition, ABAQUS was used for the purpose of analyzing the experimental results.

• Journal of Digital Convergence
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• v.21 no.1
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• pp.29-34
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• 2023

The purpose of this study was to find out the relationship between the frequency of consumption of sports drinks and energy drinks and aerobic physical activity in the 6-29 year old group in the National Health and Nutrition Examination Survey. The sociodemographic characteristics, aerobic physical activity, and beverage intake of the subjects were calculated using composite sample descriptive statistics, and the mean difference between groups was analyzed by cross-tabulation, χ²-test, and binary logistic regression analysis. High-intensity aerobic activity was analyzed as an increase in the intake frequency of sports drinks(ionic drinks, vitamin drinks) and energy drinks(high-caffeine drinks) (p<0.05). Compared to moderate-intensity aerobic physical activity, high-intensity aerobic physical activity was analyzed as a factor influencing the increase in beverage intake frequency. The purpose of this study was to investigate the relationship between physical activity and beverage consumption, which is a critical issue for promoting health both now and in the future, and to developed an intervention program based on the findings. Through this study, we aimed to gather basic data that can help people live healthy lives, and raise both individual and societal awareness of the importance of making better beverage choices.

• Convergence Security Journal
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• v.22 no.2
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• pp.121-130
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• 2022

Recently, as soldiers are allowed to use mobile phones, cases are frequently transferred from the police to the military due to criminal acts, and digital evidence is collected separately from the reliability of previous investigations, such as overlapping seizure and search procedures. In this study, through in-depth interviews with practitioners in charge of digital evidence in the military, police, and courts, problems related to digital evidence handling, such as infringement of evidence ability due to overlapping human factors and procedures, are derived and analyzed. The presented procedure verified the effectiveness of the procedure through case analysis, and is expected to contribute to the guarantee of the evidence capacity of digital evidence and the efficiency of handling cases.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.20 no.3
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• pp.97-114
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• 2009

The roles and services of a library have historically been influenced and developed by the change of information technologies. The ubiquitous technologies have been widely studied for medical area, construction, commerce, broadcasting, telecommunication and so on. The ubiquitous technologies have extended to the roles and services in a library. The development of ubiquitous IT, the roles and functions of a library and information center should be changed. To adjust evolving environment, this study focuses on concept and definition of ubiquitous computing and networks. Especially, with requirements and essential technologies which can be a technological infrastructure for ubiquitous life, library services and roles in ubiquitous life are discussed by literature review, case analysis and expert interview. With the results, this study proposes that library services and roles in ubiquitous life should be considered in two ways which are network and physical spaces. Also, roles of a library in ubiquitous life will be extended to culture and education center including traditional information center. To perform those roles and services, a library should develop various service programs relating culture and education such as personalized service and educational program.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3A
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• pp.323-330
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• 2008

The ship collision analysis of steel pile group as protection system of bridge in navigable waterways was performed to analyze the structural characteristics of protective structure during ship collision. The analysis encompassed finite element modeling of ship and pile, modeling of material non-linearity, hard impact analysis, displacement-based analysis and soft impact analysis for collision scenarios. Through the analysis of hard impact with a rigid wall, impact load for each collision type of ship bow was estimated. In the displacement-based analysis the estimate of energy which protection system can absorb within its maximum horizontal clearance so as to secure bridge pier from vessel contact during collision was performed. Soft impact analysis for various collision scenarios was conducted and the collision behaviors of vessel and pile-supported protection system were reviewed for the design of protection system. The understanding of the energy dissipation mechanism of pile supported structure and colliding vessel would give us the optimized design of protective structure.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.69-69
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• 2022

2010년부터 2019년까지 지난 10년간 한국의 ODA 현황을 규모와 유형 측면에서 살펴보면, 양자 간 원조 중 유·무상원조 비중은 큰 변동 없이 OECD DAC 회원국의 평균을 밑돌고, 다자 간원조는 21~31% 수준을 유지하고 있다. 프로젝트 원조가 꾸준히 가장 큰 비중을 차지하며 사회 인프라 및 서비스 분야에서 가장 많은 사업이 추진되고 있다. 특히, 수자원과 위생 부문은 사회 인프라 및 서비스 분야에서 보건(33%)과 교육(25%)에 이어 가장 높은 비중(19%)을 차지하고 있다(10년 누계, 약정 기준). 2020년 7월, 현 정부는 '개발 협력을 통한 코로나19 회복력 강화 프로그램(Agenda for Building resilience against COVID-19 through development cooperation, 일명 ABC 프로그램)'을 발표하고, 개도국의 경제·사회 회복력 강화를 위하여 기존 ODA 사업에 ICT와 친환경 사업 요소를 접목한 디지털 및 그린뉴딜 ODA 사업을 적극 발굴, 추진하겠다고 밝혔다. 지난 10년간, 한국과 가장 많은 다자 간 원조를 추진한 지역개발은행(36%)과 세계은행그룹(35%)에서도 코로나19와 같은 위기극복하기 위한 뉴노멀로서 환경 사업의 비중을 높이고 있다. 예컨대, 아시아개발은행은 코로나19에 대응하기 위한 도시 차원의 단·중기 행동 계획으로 도시 상하수도 시설의 지속적인 원활한 운영과 필수적인 물, 위생, 보건(WaSH) 서비스 제공을 최우선적인 조치로 발표하였다. 이러한 배경에서 본 연구는 한국의 ODA 정책 방향을 검토하고 국제사회의 추진 동향을 분석하여 향후 한국이 특화하고 경쟁력을 가질 수 있는 환경 분야의 ODA 전략을 제시하고자 한다. 본 연구 결과는 ODA를 통해 해외 진출을 도모하는 민간기업과 국력 향상의 수단으로써 ODA를 적극적으로 활용하겠다는 기조를 지닌 새 정부의 ODA 전략 수립에 기여할 수 있을 것이다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.5
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• pp.721-736
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• 2023

The Command and Control Framework was developed for penetration testing and education purposes, but threat actors such as cybercrime groups are abusing it. From a cyber threat hunting perspective, identifying Command and Control Framework servers as well as proactive responding such as blocking the server can contribute to risk management. Therefore, this paper proposes a methodology for tracking the Command and Control Framework in advance. The methodology consists of four steps: collecting a list of Command and Control Framework-related server, emulating staged delivery, extracting botnet configurations, and collecting certificates that feature is going to be extracted. Additionally, experiments are conducted by applying the proposed methodology to Cobalt Strike, a commercial Command and Control Framework. Collected beacons and certificate from the experiments are shared to establish a cyber threat response basis that could be caused from the Command and Control Framework.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.619-624
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• 2023

As the importance of digital competency education is highlighted, this study is a case study on block coding classes for elementary school students during vacation for the purpose of bridging the information education gap among students. The purpose of this study is to design and operate a play-centered block coding class program and find out if it is effective in improving students' interest. As a result of completing the teaching plan through the second consultation and revision, running the class, and analyzing the change in learning interest of the students through the t-test, the play-oriented block coding class designed in this study was effective in improving students' interest. In addition, it was possible to discover interesting elements such as student-led learning process and immersion through realistic play activities, friendship, collaboration, and communication through group activities. This study is significant in suggesting a plan to increase learning interest for students who are new to coding.

• The Journal of the Acoustical Society of Korea
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• v.26 no.8
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• pp.375-380
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• 2007

A reverberation chamber should be designed and constructed so as to satisfy its purposes and available space. However, it is somewhat difficult to meet the intended design requirements due to various errors from construction process. So, the post-construction measurement of its volume and surface areas is very essential to check the actual volume and volume uncertainty of a reverberation chamber These values should be carefully calculated and accurately estimated since they are used not only to evaluate the acoustic characteristics of building materials but also to calculate uncertainties for other acoustic characteristics. In this work, the method for the calculation and uncertainty estimation of the volume of a reverberation chamber is presented. To this end, the coordinates of all corners was measured with Total Station after construction. The results showed that the calculated volume of the measured reverberation chamber differs by 5 % from the design specification. The expanded volume uncertainty was also estimated to be about 2 % of the total calculated volume.

• Journal of the Korean Chemical Society
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• v.48 no.4
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• pp.358-366
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• 2004

The bridged disulphato complex $[Cr_2(NH_2)_2(H_2O)_2(SO_4)_2]{\cdot}2H_2O$, terminal triisocyanato $[Cr(NCO)_3(H_2O)]{\cdot}3H_2O$ complex and limonite, $[FeO(OH)]{\cdot}0.2H_2O$ compound were prepared by the reaction of $Cr_2(SO_4)_3{\cdot}xH_2O, Cr(CH_3COO)_3$ and $Fe_2(SO_4)_3$, respectively, with urea in aqueous media at $80^{\circ}C$. The infrared spectra of the products indicate that the absence of the bands of urea, but shows the characteristic bands of coordinated amide, water, bridged sulphato and isocyanato groups. Thermogravimetric (TG) and differential thermal analysis (DTA) measurements on the complexes are also recorded. The data obtained agree quite well with the expected structures. A general mechanisms describing the formation and its thermal decomposition of the complexes are suggested.