• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.2
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• pp.188-196
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• 2023

Among marine accidents caused by bad weather, visibility restrictions caused by sea fog occurrence cause accidents such as ship strand and ship bottom damage, and at the same time involve casualties caused by accidents, which continue to occur every year. In addition, low visibility at sea is emerging as a social problem such as causing considerable inconvenience to islanders in using transportation as passenger ships are collectively delayed and controlled even if there are local differences between regions. Moreover, such measures are becoming more problematic as they cannot objectively quantify them due to regional deviations or different criteria for judging observations from person to person. Currently, the VTS of each port controls the operation of the ship if the visibility distance is less than 1km, and in this case, there is a limit to the evaluation of objective data collection to the extent that the visibility of sea fog depends on the visibility meter or visual observation. The government is building a marine weather signal sign and sea fog observation networks for sea fog detection and prediction as part of solving these obstacles to marine traffic safety, but the system for observing locally occurring sea fog is in a very insufficient practical situation. Accordingly, this paper examines domestic and foreign policy trends to solve social problems caused by low visibility at sea and provides basic data on the need for government support to ensure maritime traffic safety due to sea fog by factually investigating and analyzing social problems. Also, this aims to establish a more stable maritime traffic operation system by blocking marine safety risks that may ultimately arise from sea fog in advance.

• Journal of Gifted/Talented Education
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• v.26 no.4
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• pp.699-719
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• 2016

Alternate pictures that are proven to be equivalent are in high demand to assess creative thinking and language skills. This study aimed to investigate the equivalence of three pictures ('Dog owners,' 'Lost Dog,' and 'Overslept') recently developed for use in a creative writing task. Middle school students (N=183) wrote a story in English based on one of the three prompts distributed randomly. Four writing features (fluency, syntactic complexity, lexical diversity, and temporality) were analyzed with Coh-Metrix and MANCOVA. The three prompts were largely equivalent in their capacity to detect differences among writers in all the features of writing. The difficulty levels of the three prompts, however, were not necessarily the same. Two prompts, Dog Owners and Lost Dog, were verified as equivalent prompts, and therefore, they are recommended as alternate forms to assess creative language skills in repeated measurements. The Overslept prompt had greater facility in eliciting diverse words and more temporal connectives in composing stories. The differential difficulty shown among the prompts suggests that the validity of using different picture versions in repeated assessment remains questionable unless those versions undergo equivalence verification.

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.613-619
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• 2014

A flare system is a very important system that crucially affects on the process safety in chemical plants. If a flare system is designed too small, it cannot prevent catastrophic accidents of a chemical plant. On the other hand, if a flare system is designed too large, it will waste resources. Therefore, reasonable relief load estimation has been a crucial issue in the industry. American Petroleum Institute (API) suggests basic guidelines for relief load estimation, and a lot of engineering companies have developed their own relief load estimation methods that use an unbalanced heat and material method. However, these methods have to involve lots of conservative assumptions that lead to an overestimation of relief loads. In this study, the new design procedure for a flare system based on dynamic simulation was proposed in order to avoid the overestimation of relief loads. The relief load of a deethanizer process was tested to verify the performance of the proposed design procedure.

• Journal of Energy Engineering
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• v.23 no.3
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• pp.146-149
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• 2014

Compared to Butane tank, the propane tank should have a higher compressive strength due to its higher vapor pressure. In this study, a theoretical analysis was performed to evaluate the effect of change in the geometry of bottom plate on the mechanical property of tank, and an experiment was also carried out to observe the propensity of the deformation and failure of the vessel using hydraulic pressurizing device. The compressive strength of the vessel was observed to improve 1.5-2.5 MPa as the curvature of the bottom plate was decreased 62 mm and the thickness of the bottom plate was increased 0.25 mm. This study are expected to provide viable information conducive to achieve on-going development of a small vessel for the pressurized propane gas.

• Journal of The Korean Association of Information Education
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• v.19 no.2
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• pp.159-166
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• 2015

STEAM is a multidisciplinary education program which intended to promote creative thinking by combining studies in the arts and STEM(Science, Technology, Engineer, Mathematics) fields. STEAM education can bring out creativities in students through educational activities of integrating and combining diverse studies. In this research, we integrated the educational elements of science, technology, engineering, mathematics, and arts using robots and then developed an educational program that raises the creative and character (focused on collaboration and communication) of students in a more fun and effective way. Using our developed educational program, we taught 6th grade students of an elementary school located in Seoul. As the result, most of students were found to be enhanced in their creativity and character after participating in the STEAM-based programming education course.

• Journal of the Korea Concrete Institute
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• v.27 no.4
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• pp.377-385
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• 2015

The span-lengthening of PSC I girder has increased the risk of lateral instability of the girder with the increases in the aspect ratio and self-weight of the girder. Recently, collapses of PSC I girder during construction raise the necessity of evaluating the lateral instability of the girder. Thus, the present study evaluated the lateral behavior and instability of PSC I girders under wind load, regarded as one of the main causes of the roll-over collapse during construction. Lateral instability of the girder is mainly dependent on the length of the girder and the stiffness of the support. The analysis results of this study showed the decrease in the critical wind load and the increase in the critical deformation and angle of the girder, leading to the lateral instability of the girder. Finally, this study proposed analytical equations that can predict the critical amount of wind load and lateral deformation of the girder, which would provide quantitative management values to maintain lateral stability of PSC I girder during construction.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.103-103
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• 2011

비스코스레이온(Viscose Rayon)소재는 목재 펄프를 원료로 한 재생섬유(습식방사)로서 Drape성과 반발성은 탁월하나, 습식방사에 따른 분자구조적 불안정성으로 건 습열처리시 형태불안정(치수변화율이 큼)으로 제직(준비) 및 후공정상 여러 가지 Trouble 유발과 완제품 세탁시 수축발생으로 종종 Dry Creanning 해야 하는 문제점들이 내재되어 있다. 또한 수분흡수시 강도저하, 수축과 구김, 염색 불균염 등의 문제점과 섬유공정상 생활취급상에 많은 애로를 가지고 있으며, 구성고분자가 수소결합에 의해 강고하여 "신축문제", 수분흡수시 팽윤(Swelling)에 의한 형태불안, 즉 "수축문제"가 개선해야 할 고질적 문제로 남아있다. 따라서 본 연구에서는 레이온 소재의 형태안정화 제품을 개발하기 위하여 복합사고공 및 염색가공 기술을 개발하고자한다. 신축 및 복합기술에 의한 Rayon DTY, N/R 신축 및 복합기술에 의한 Rayon DTY, N/R 복합가공사를 개발, 제편직 요소기술과 염가공기술을 연구하므로서 형태안정성 레이온 복합소재 제품을 개발하고자 한다. Rayon 소재의 후공정 용이성과 형태안정성을 부여하기 위하여, 레이온 DTY가공사, Rayon-합섬 장(長)-장(長) 복합사를 개발하여 CoolBiz용 냉감소재 및 스포츠 웨어 소재 등으로 활용하고자 한다. 사가공기술에 의한 신도 16%, 수축률 1.6%인 형태안정 Rayon DTY 소재를 개발하였으며, 선연후가공기술에 의하여 N/R 복합가공사를 개발, 신도 18%, 수축률 1.2%인 차별화 레이온 소재를 개발하였다. 이에 기존 Rayon 후가공 및 염색공정과 상이한 개발된 선연후 가연 Rayon DTY가공사 및 T/R혼방사를 활용한 직물에 대하여 최적 전처리, 염색 후가공 공정의 최적 조건을 알아보았다.

• International Journal of Highway Engineering
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• v.6 no.4 s.22
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• pp.35-43
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• 2004

Skid resistance is an important factor that control braking distance and secure safety by preventing slipperiness between tire and pavement surface. Decrease of skid resistance at wet condition may cause fatal traffic accidents. Dirt materials such as sand and do-icings on the road surface also can be a factor for decrease skid resistance. This study makes an investigation into influence of skid resistance between varied cement concrete pavements about surface texturing method(transverse tining, longitudinal tining, exposed aggregate surface texturing method) and wearing condition of pavement surface texture(new constructed pavement's surface, wore pavement's surface) using accelerate concrete pavement wearing tester when remains of dirt material are obtained between tire and road surface on PCC pavement. As dirt material on road surface of concrete pavement, sand, calcium chloride and old oil were used with different amount of each cases.

• Journal of The Korean Association of Information Education
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• v.21 no.5
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• pp.497-507
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• 2017

Research on software education and linking and convergence of other subjects has been mainly focused on mathematics and science subjects. The dissatisfaction of various preferences and types of learning personality cause to learning gap. In addition, it is not desirable considering the solution of various fusion problems that can apply the computational thinking. In this way, it is possible to embrace the diverse tendencies and preferences of students through the linkage with the English subject, which is a linguistic approach that deviates from the existing mathematical and scientific approach. By combining similarities in the process of learning a new language of English education and software education. For this purpose, based on the analysis of teaching - learning model of elementary English subject and software education, we developed a class model by modifying existing English subject and software teaching - learning model to be suitable for linkage. Then, the learning elements applicable to software education were extracted from the contents of elementary school English curriculum, and a program applied to the developed classroom model was designed and the practical application method of learning was searched.

• The Journal of Korean Association of Computer Education
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• v.12 no.1
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• pp.15-22
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• 2009

Computer programming language learning has an educational effect on improving the high level abilities such as a logical thinking ability and a problem solving ability as well as on understanding a computer working process through the process of programming and debugging tasks. In this study, the Flow Theory is applied for the students to have inner learning motive and continue their learning in the programming language learning. For this, we developed teaching-learning strategies applied by Flow elements, and designed to the WBI. We also applied to the actual teaching-learning field designed WBI and verified the effects on the changes in the learner's Flow level and academic achievement. The result of verification, WBI learning applied by Flow Theory is effective on improving Flow level, making the students have the learning goal and spirit of challenging, forming feedbacks. Also Flow experiences have effect on improving academic achievement(programming ability) through the positive effects on the results of the learning.