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Evaluation of Seismic Performance of Pile-supported Wharves Installed in Saturated Sand through Response Spectrum Analysis and Dynamic Centrifuge Model Test (동적원심모형실험 및 응답스펙트럼해석을 통한 포화지반에 관입된 잔교식 안벽의 내진성능 평가)

  • Yun, Jung-Won;Han, Jin-Tae;Lee, Seokhyung
    • Journal of the Korean Geotechnical Society
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    • v.37 no.12
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    • pp.73-87
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    • 2021
  • Pile-supported wharf is a structure that can transmit and receive cargo, and it is mainly installed on saturated inclined ground. In the seismic design of these structures, the codes suggest using the response spectrum analysis method as a preliminary design method. However, guideline on modeling method for pile-supported wharf installed in saturated soil is lacking. Therefore, in this study, the dynamic centrifuge model test and response spectrum analysis were performed to evaluate the seismic performance of pile-supported wharf installed into the saturated soil. For the test, some sections (3×3 pile group) among the pile-supported wharf were selected, and they were classified into two model (dry and saturated sand model). Then the response spectrum analysis was performed by using the soil spring method to the test model. As a result of test and analysis, the m om ent difference occurred within a m axim um of 51% in the dry sand m odel and the saturated sand model where liquefaction does not occur, and it was found that the pile moment by depth was properly simulated. Therefore, in the case of these models, it is appropriate to perform the modeling using the Terzaghi (1955) constant of horizontal subgrade reaction (nh)

A Study on the Characteristics of the Creation Process of Convergence Performing Arts - Focusing on PADAF - (융·복합 공연예술 창작과정의 특징 연구 - 파다프(PADAF)를 중심으로)

  • Jo, Jeong-Min
    • Journal of Korea Entertainment Industry Association
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    • v.14 no.8
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    • pp.163-174
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    • 2020
  • The purpose of this study is to derive the characteristics of the creative process of convergence performing arts. Therefore, the PADAF-Play and Dance Art Festival, a representative convergence performing arts festival in Korea that has been held steadily every year since the first event in 2011, was selected as the subject of the study. Through PADAF, a representative convergence performing arts festival in Korea, qualitative case studies were selected through process-oriented discovery to study the characteristics of the creative process of convergence performing arts, which is a key feature of performing arts in the 21st century. For realistic and empirical research, the 8th and 9th PADAF participated in the entire process from the initial stage of preparation to the closing ceremony and conducted several in-depth interviews with PADAF officials and participating artists. Looking at the characteristics of the convergence performance art creation process through PADAF, creators overcame difficulties that they had not thought of in different ways in the process of meeting different heterogeneous genres, but through understanding other genres, experiential values through convergence, sharing as collaborators, and various ways of communication. The characteristics of the convergence performing arts creation process, which is focused on PADAF, are "Rhizom thinking" by French philosopher Gilles Deleuze(1925-1995), "Collective intelligence," and "Experimental Value for Experimental Creation" by creators. Through this derivation, we will help the changing performing arts scene based on the basic human desire to understand convergence performance art a little more and communicate through the extended expression of convergence.

Randomized clinical trial to evaluate the efficacy and safety of two types of sandblasted with large-grit and acid-etched surface implants with different surface roughness

  • Jeon, Jun-Hyung;Kim, Min-Joong;Yun, Pil-Young;Jo, Deuk-Won;Kim, Young-Kyun
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.48 no.4
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    • pp.225-231
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    • 2022
  • Objectives: This study aims to evaluate the efficacy and safety of two types of sandblasted with large-grit and acid-etched (SLA) surface implants with different surface roughness. Patients and Methods: This study was conducted based on a clinical record review of 55 patients (mean age, 53.00 years). A total of 80 SLA surface implants was placed. Among the 80 implants, 38 implants placed in 29 subjects had surface roughness (Ra) of 3.09 ㎛ (test group, TG), while the other 42 implants placed in 31 subjects had a surface roughness (Ra) of 2.50 ㎛ (control group, CG). A comparison was made of implant primary/secondary stability; success and survival rates; marginal bone loss; and soft tissue assessment including probing pocket depth (PPD), plaque index (PI), gingival index (GI), and bleeding on probing (BOP) between the groups at 1 year after implant placement. Results: Among the implants that were initially registered, 1 from the TG and 4 from the CG dropped out, leaving 37 implants in the TG and 38 implants in the CG to be traced and analyzed. Although 1 TG case showed unstable primary stability, all cases showed stable secondary stability. Success and survival rates at 1 year after implant placement were 100% in both groups. Marginal bone loss was 0.07 mm and 0.00 mm for the TG and CG, respectively, but the difference was not significant. Among the several parameters for evaluation of soft tissue, the TG showed lower PI at 1 year after implant placement (TG=0.00, CG=0.29; P=0.0004), while the remaining categories showed no significant difference between the groups. Conclusion: This study shows that the two types of SLA implants with different surface roughness have no difference in efficacy or safety. Therefore, both of the implants can be used safely and with promising outcomes.

A Narrative Inquiry of Elementary School Science and Online Class Experiences (초등학교 교사의 과학과 온라인 수업 경험에 대한 내러티브 탐구)

  • Kim, Yoon-Kyung
    • Journal of the Korean Society of Earth Science Education
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    • v.15 no.2
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    • pp.273-284
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    • 2022
  • This study was conducted to examine the practical and educational implications of teachers' operation of the curriculum through science and online classes based on data collected for 4 months from 4 teachers who had experience in science subject online classes among homeroom teachers in the 3rd to 6th grades of elementary school in D city. This study was conducted through narrative inquiry. As a result of conducting interviews and in-depth interviews based on the online class experiences of the Earth Science Unit of the study subjects, and conducting field classes with related documents such as online class-related materials and teacher journals, teachers were more likely to take online classes compared to traditional face-to-face classes. They spent more time preparing and showed difficulties in the process of adapting to the new medium used in online classes. In addition, they demanded the provision of scientific materials produced in a pandemic situation and a teaching platform for smooth class operation. In particular, in the case of experimental classes, there is a burden of completing the planned curriculum, and in a pandemic situation, students felt the need for individual experimental tools for intensive science classes. As a result, it is necessary to introduce a blended learning learning system that combines the advantages of face-to-face and online classes as a new class form for the transition to future education in preparation for the pandemic. Continuous teacher research on the format and online class experience is required.

A Study on the Analysis of Current Issues and the Operation Plan of News Media Asset Management System in Korean Broadcasting Companies: the Case Study of KBS Digital Newsroom (방송사 보도영상관리시스템 운영 현황분석과 개선안 연구 - KBS 디지털뉴스룸 사례를 중심으로 -)

  • Choi, Hyo-jin;Park, Choonwon;Kim, Sooyoung;Song, Jeonga;Park, Yeajin;Shin, Bongseung;Ji, Sunho;Sun, Sangwon
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.33 no.3
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    • pp.123-155
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    • 2022
  • This study focuses on the management of the news production system in broadcasting companies. This paper concentrates on the process of data registration and metadata management in order to examine whether the currently produced news can have value as a 'public record' in the long term, and whether reliable and accurate information is preserved. In addition, the user experience in the current system is analyzed through in-depth interviews with Ingest Managers, Editors, and Archive Managers, who are closely related to metadata creation compared to other members of the its News Department. Finally, a sustainable metadata quality management method is sought to increase the value of news footage as a 'public record'. In this study, these points can be found out: the metadata of the news agency footage is input manually according to the user's will or working style, that is, the user-friendly metadata input system is insufficient. Accordingly, it can be seen that the quality of the metadata of the news video continues to deteriorate. As an alternative to overcome this, it is found that work flow improvement, system improvement, classification system and metadata improvement plan, etc. are definitely necessary in the short and long term.

A Study on Deriving Strategic Tasks of Continuing Education Institutions for Librarians Applying PEST-3Cs-SWOT (PEST-3Cs-SWOT 방법론을 적용한 사서 계속교육 기관의 전략과제 도출에 관한 연구)

  • Jung, Youngmi;Noh, Younghee
    • Journal of Korean Library and Information Science Society
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    • v.53 no.3
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    • pp.343-376
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    • 2022
  • Continuing education for professionals is the most basic requirement for continuous professional development. The enhancement of the professionalism of librarians will also be possible through the establishment of a systematic continuing education strategy of the national level. In this study, we tried to derive a strategy for continuing education for librarians in Korea by analyzing the internal and external environment of national institutions that are the center of continuing education for librarians. To this end, we proposed a complex framework of PEST-3Cs-SWOT as a systematic environmental analysis methodology and tried to apply it. For PEST analysis, literature related to library, librarian, and librarian education was extensively reviewed, and for 3Cs analysis, in-depth interviews with internal employees, questionnaire data analysis on the demand survey of training subjects, and case studies of similar institutions in Korea and abroad were conducted. Based on this, SWOT analysis was conducted, and finally, 4 strengths-opportunity strategic tasks, 5 weaknesses-opportunity strategic tasks, 5 strength-threat strategic tasks, and 3 weaknesses-threat strategic tasks were derived. This study will be meaningful in that it presents strategic tasks for continuing education institutions in Korea, and at the same time suggests and applies a complex analysis methodology that can be applied to tasks similar to development plans and strategy establishment.

A Study on the Frictional Characteristics of Fiber Reinforced Composites under Corrosive Environment (부식 환경 하에서의 섬유강화복합재료의 마찰 및 마모 특성 연구)

  • Choong-Yong Park;Dong-Hyun Park;Soo-Jeong Park;Yun-Hae Kim
    • Composites Research
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    • v.36 no.1
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    • pp.37-41
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    • 2023
  • The treated water inside the ballast electrolytic cell creates a highly alkaline atmosphere due to hydroxide generated at the DSA(Dimension Stable Anode) electrode during electrolysis. In this study, a composite material that can replace the weakness of the PE-coated steel pipe used in the existing ballast pipe was prepared. The test samples are BRE(Basalt fiber reinforced epoxy), BRP(Basalt fiber reinforced unsaturated polyester), GRE(Glass fiber reinforced epoxy), and GRP(Glass fiber reinforced unsaturated polyester). And then it was immersed in NaOH for 720 hours. The friction test of each specimen was conducted. The Friction coefficient analysis according to material friction depth and interfacial adhesion behavior between resin and fiber were analyzed. As a result, the mechanism of interfacial separation between resin and fiber could be analyzed. In the case of the unsaturated polyester resin with low interfacial bonding strength the longer the immersion time in the alkaline solution, the faster the internal deterioration caused by the deterioration that started from the surface, resulting in a decrease in the friction coefficient. It is hoped that this study will help to understand the degradation behavior of composite materials immersed in various chemical solutions such as NaOH, acid, and sodium hypochlorite in the future.

A Study on Non-Destructive Safety Evaluation Platform of Internal Defects of the Composite Hydrogen Tank using Finite Element Analysis (유한요소해석을 이용한 수소압력용기 비파괴 시험 평가 플랫폼의 안전성 기준 개발 연구)

  • Yongwoo Lee
    • Journal of Platform Technology
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    • v.10 no.4
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    • pp.3-10
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    • 2022
  • In this study, damage resulting from internal flaws was investigated by finite element analysis for the safety evaluation of a non-destructive testing platform for hydrogen pressure vessels. A specimen was modeled and calculated using finite element analysis to determine material properties in accordance with the parameters of the composite material in order to assess the safety of the Type 4 hydrogen pressure vessel. Through this, flaws in the hydrogen pressure vessel were modeled, and test conditions were provided in accordance with rules to look into whether there was safety. Delamination, foreign object, and vertical cracks were modeled for internal flaws, and damage was examined in accordance with failure criteria. As the delamination defect approached the interior of the hydrogen pressure tank, it became more likely to cause damage. Additionally, as the crack depth grew in the case of vertical cracks, the likelihood of crack propagation rose. On the other hand, it was anticipated that the foreign item defect would suffer more damage from the outside in. A non-destructive testing platform will be used to assess the safety of fuel cell vehicles that are already in operation in future research.

Appropriateness Evaluation of Train Vibration Evaluation Method Considering Vibration Levels of Retaining Wall Adjacent to Railway Tunnels (철도터널과 인접한 흙막이 가시설의 진동 수준을 고려한 열차진동 평가방법의 적정성 평가)

  • Donghee Woo;Yeongjin Lee;Yongjae Song;Kangil Lee
    • Journal of the Korean GEO-environmental Society
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    • v.24 no.10
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    • pp.5-13
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    • 2023
  • With the recent increase in development projects centered on urban areas, the construction of building structures is increasing in areas adjacent to the urban railway operation section. In this case, since ground vibration is generated by the train in operation and affects the adjacent structure, the building structure needs appropriate vibration reduction against train vibration generated at the adjacent location from the desing phase. However, the vibration levels calculated vary depending on the train vibration evaluation method, which means that the implementation of vibration reduction may vary depending on the train vibration evaluation method. Therefore, this study calculated the vibration level according to ground conditions, tunnel depth and separation distance between vibration sources and adjacent structures using numerical analysis and train vibration evaluation methods, and compared them to designning phase. And the appropriate separation distance between the tunnel and the adjacent structure was evaluated by comparing the vibration level with the allowable standards. As a result of the study, the Ungar and Bender evaluation method is evaluated as the most appropriate among the train vibration evaluation methods, and the appropriate separation distance between the tunnel and the adjacent structure is evaluated to be more than 4.5D.

A Case Study on the Improvement of Sociality in Convergence Theater Education : Focusing on a Theatrical Camp Milmi-ri Village School (융합연극교육의 사회성 발달 증진 효과사례 분석 : 연극캠프 밀미리 마을학교를 중심으로)

  • Kim, Jung-Sun;Bae, Jin-Sup
    • Journal of Korea Entertainment Industry Association
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    • v.13 no.6
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    • pp.221-233
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    • 2019
  • The purpose of this study tries to show the effectiveness of integrated theater education for low-grade students who lack social skills with the direction of art education based on 'theatrical and educational theater' and 'theater therapy' in the revised curriculum in 2015. To do this, the researcher organized a theater camp organized by the social, cultural and arts education institute in Seoul for a total of 12 low-grade elementary school students for four weeks, and had a presentation session. In addition, the researcher observed the behavioral changes of the participating children to verify the social development of the theater education and after the conclusion, the final results were obtained through the in-depth interviews of the participants' parents and teachers. As a result, it was found that Social Skills Rating System(SSRS)' test, teachers' observation logs, interviews, and responses of participating children, which are the main subjects of this activity, had a great effect on improving their sociality and relationship. Therefore, the researcher tried to prove through this paper that theater education is effective in enhancing social skills as creative, personality and convergence education in preparation for the 4th industrial era and that it is important to solve communication problems such as the absence of human relationships.