• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2C
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• pp.95-107
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• 2010

To calculate the end bearing capacity of a drilled Shaft socketed into the rockmass, the unconfined compression strength could be used. But it is difficult to find the unconfined compression strength because it is impossible to get undisturbed samples in weathered soils and rocks. So, to calculate the end bearing capacity, the existing bearing formula could not be used. In this study, for five zones (near pile tip, tip~lower 1D, tip~lower 2D, upper 1D~lower 1D, upper 1D~lower 2D), the relationships between the characteristic values of in-situ tests(SPT, DCPT PMT, BST) and the end bearing capacity of drilled shafts were analysed. As a result, DCPT results were represented the best credibility. Also, a design chart of end bearing capacity using DCPT was suggested.

• International Area Studies Review
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• v.15 no.1
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• pp.135-169
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• 2011

This study is for analyzing the management performances of Korean tourism firms, operating as preparing strategically against FTA which is one of the most importantly external environment in international management since in the middle of 1990s. The main purpose is to test empirically some relations between the management performances and the levels of ownership-specifics advantages of Korean tourism ones. To be exact, the dependent variables of management performances are classified with sales, profits and management satisfaction, while the independent ones of the competitive advantages are sorted with the 5 following factors like marketing, product development, service supply, finance and organization culture. The survey of Korean tourism enterprises engaging in management activities in Korea is implemented by collecting questionnaires. And for testing the hypothesis, the analyzing tools are being used for correlation, reliability, validity, multi regression and the path analysis of structural equation modeling. As a result, Marketing is certified as only common factor to influence three dependent variables of sales, profit and management satisfaction positively.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.331-332
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• 2022

After the Great East Japan Earthquake, reports and books that compiled the testimonies of the victims were published and the situation of the evacuation at that time became known. However, there is very little information on the evacuation situation of children among these data, and it is not fully known what actions the children took and how they evacuated due to an earthquake or tsunami. The purpose of this study is to analyze and examine children's evacuation behavior in the Great East Japan Earthquake, and to predict children's evacuation behavior for future disasters.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.362-365
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• 2022

With the development of the 4th industrial revolution technology, smartization in various fields is accelerating. The shipping and logistics industry is also promoting smartization by combining advanced new technologies such as digital twin, Internet of Things, and artificial intelligence. In Korea, the Ministry of Maritime Affairs and Fisheries is promoting a strategy to spread the smart shipping logistics system in line with the changing global shipping logistics trend, and through this, it is creating a foundation for smart shipping logistics. This study aims to present the concept of a communication tool that recognizes the importance of communication between each logistics entity and exchanges opinions between logistics entities in a virtual digital twin environment to cope with the changing shipping logistics process. In addition, for the development of these communication tools, this study derive a software design model, including architecture.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.17-17
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• 2020

나고야의정서 발효에 따라 이에 대한 대응이 전세계적인 이슈가 되면서 각 국가들은 자국내 유용자원식물의 주권확립을 위한 움직임을 보이고 있으며 이들의 기원종 확립과 진위 감별을 위한 연구가 활발히 진행되고 있다. 이에 본 연구에서는 전라도 지역 내 생약 자원식물의 분포현황 및 실체를 파악하고자 하였다. 조사시기는 2018년 3월부터 2020년 5월까지 계절별로 해안가, 산지, 농경지 등 다양한 서식환경에 대하여 조사를 실시하였다. 전라도 내에서 확인되 생약자원식물은 106과 243속 405종 31변종 4품종 총 440분류군이 분포하는 것으로 조사되었으며, 한반도 관속식물 4,499분류군(Korea National Arboretum, 2018; Http://www.nature.go.kr/kpni/)의 9.8%에 해당된다. 본 조사지역 내에서 확인된 생약자원 식물 중, 특산식물로는 매미꽃, 할미밀망, 노랑붓꽃 등 11분류군이 확인되었으며, 희귀식물로는 CR등급의 노랑붓꽃을 포함하여, VU등급의 약난초, 흑삼릉 등 25분류군이 확인되었다. 특히 본 조사를 통해 수집된 생약자원식물의 표본, 화상자료, 종자, 생약부위 등은 추후 우리나라의 생약자원에 대한 관리DB를 구축하는데 기초자료로서 유용하게 활용될 것이다.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.551-556
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• 2023

In this study, John Burningham's picturebooks(『Come Away from The Water, Shirley』, 『Time to Get Out of The Bath, Shirley』) was analyzed using the concept of carnival among Bakhtin's conversationalism theory. In John Burningham's picturebooks, the unconscious desire for the deviation of the main character, Shirley, is transformed into an adventure in an extraordinary imaginary world, and is depicted as a festival with laughter. Through picturebooks, children are satisfied by indirectly experiencing the forbidden behavior in reality by converting it into an event in the imaginary world. This indirect experience is very important for children to naturally resolve their dissatisfaction in reality and to develop their own original inner development. This study also suggests that providing an environment where children can easily access various picturebooks at home or early childhood education institutions plays a very important role in their growth.

• Korean Journal of Childcare and Education
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• v.20 no.2
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• pp.145-167
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• 2024

Objective: This study aimed to investigate the moderated-moderated mediating effects of children's media content selection and parental restrictive media mediation on the relationship between children's screen media time and executive function difficulties. Methods: A total of 693 parents of children aged 5~6 years participated in this study and were asked to answer all survey questions. The data were analyzed by descriptive statistics and correlation analysis using SPSS 27.0. Model 11 of PROCESS macro 4.3 was used to examine the moderated-moderated mediation model. Children's gender, age, childcare enrollment status, and household income were included in the analyses as covariates. Results: The moderated-moderated mediating effects of children's media content selection and parental restrictive media mediation were found to be significant. Specifically, bedtime mediated the relationship between screen media time and executive function difficulties only when parents did not appropriately implement restrictive mediation and children freely selected media content. Conclusion/Implications: It is recommended that parents understand the importance of implementing restrictive media mediation and selecting appropriate media contents for their child to prevent executive function difficulties in early childhood. Also, child education or day-care centers should offer education program about appropriate media use to reach more parents.

• Proceedings of the Korean Society of Computer Information Conference
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• 2024.01a
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• pp.109-111
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• 2024

군사 목적으로 개발된 드론은 최근 다양한 산업 및 민간 분야로 확대되고 있으며, 이러한 확대에 따라, 드론이 급격하게 발전하여, 농업이나 무인 드론 택배와 같은 산업 전반적으로 긍정적인 효과를 창출하는 추세이다. 그러나 이러한 발전에 반하여, 드론에 장착된 카메라를 통한 사생활 침해나 테러 목적으로 활용하는 것과 같은 부정적인 측면이 드러나기 시작하였다. 특히, 드론의 위치와 밀접한 연관이 있는 GPS와 관련하여, 무인 이동체의 특성상, GPS 신호에 의존하여 사용자에게 드론의 위치를 전달하지만, 이러한 GPS 신호를 송신하는 위성은 거리가 매우 멀리 위치하고, 이에 따라, 신호 세기가 비교적 약한 문제점을 가진다. 이와 같은 문제점을 악용하는 GPS 스푸핑 공격이 등장하였으며, 이 공격은 만약 공격자가 GPS 신호를 조작하여 송신한다면, 드론에 장착된 GPS 수신기는 조작된 GPS 위치를 수신하며, 이에 따라, 드론의 제어권을 탈취하거나 충돌 유발, 비정상적인 비행 경로 유도와 같은 문제점이 발생한다. 본 논문에서는 최신의 상용화된 드론을 대상으로, GPS 스푸핑 공격의 취약점을 분석하고 실증한다. 이를 위하여, 공격자가 비행 금지 구역에 해당하는 GPS 신호를 조작하는 것으로 공격을 시도하고, 이에 따른 드론에서 준비된 동작인 강제 착륙과 같은 비정상적인 행위를 유발하여, 드론의 임무 수행 능력을 제한하는 취약점을 분석하고 실험을 통하여 실증한다. 본 논문의 결과를 토대로, 최신 드론에서 발생 가능한 보안 위협을 도출함으로써, 드론의 안전성을 향상시키기 위한 자료로 활용될 수 있을 것으로 사료된다.

• Information Systems Review
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• v.22 no.4
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• pp.115-134
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• 2020

Previous studies on willingness to pay for digital content have mainly focused on audience factors and individual level. To complement the limitation of previous research, this study conducts a multilevel analysis to find the factors influence digital content purchases considering two axes: audience/media factors and individual/household levels. Using a sample of 10,172 individuals within 4,313 households, the analysis results show individual media factors including theater-going, experience with cloud services, and multi-screen service usage have the greatest effects on digital content purchases. At the household level, the media ownership factors that the number of laptops, wireless routers, and tablets have a greater influence than audience factors such as household size or household income. Our findings help scholars to enhance the understanding of individuals' media use considering household environmental factors and shed light on the importance of multi-screen service usage, and content providers to improve their digital content sales using multi-screen environment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.90-97
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• 2024

In this study, we employed Highly Ductile Cement Composite (HDCC) to evaluate the flexural performance of a RC slab that simulates the laminating structure of a seashell. To evaluate flexural performance, we produced conventional RC slab specimens, HDCC slab specimens, and HDCC-M slab specimens which biomimics a seashell's layered structure by inserting PE mesh inside the slab made of HDCC. A series of 4-point bending tests were conducted. Experimental results shows the flexural strength of the HDCC-M slab specimen was 1.7 times and 1.2 times higher than that of the RC and HDCC slab specimens, respectively. Furthermore, the ductility was evaluated using the ratio of yield deflection to maximum deflection, and it was confirmed that the HDCC slab test specimen exhibited the best ductility. This is most likely due to the fact that the inserted PE mesh separates the layers and increases ductility, while the HDCC passing through the mesh prevents the loss of load carrying capacity due to layer separation.