• Title/Summary/Keyword: 모형빙

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A Study on Improvement of Ice Model Test Procedure (빙수조 모형시험법 개선 연구)

  • Lee, Chun-Ju;Cho, Seong-Rak;Lau, Michael;Wang, Jung-Yong
    • Journal of the Society of Naval Architects of Korea
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    • v.45 no.5
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    • pp.562-568
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    • 2008
  • In this study, the target FSICR class is 1A whose target thickness of the brash ice is 46 mm in model scale. Normally ice floes for brash ice do not exceed 2 m in full scale, so the model ice sheet was cut by about 10 cm by 10 cm using hand saws. Since the target thickness of brash ice is 46 mm, 46 mm ice sheet makes one layer brash ice. For 23 mm thickness ice sheet, two layers should be accumulated to reach 46mm brash ice thickness. For 15mm thickness ice sheet, three layers need to be accumulated as the same as those in 23 mm ice sheet. New methodology to produce a brash ice was proposed. The results showed that it would be important to use multi-layer rather than single layer possibly because of significant thrust deduction from the propeller-ice interaction in the present ice condition (FSICR 1A).

A Study on Resistance Test of Icebreaker with Synthetic Ice (합성 얼음을 사용한 쇄빙선 저항시험에 대한 연구)

  • Song, Yun-Young;Kim, Moon-Chan;Chun, Ho-Hwan
    • Journal of the Society of Naval Architects of Korea
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    • v.44 no.4
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    • pp.389-397
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    • 2007
  • This research describes a framework to compare and analyze the icebreaker(Terry Fox) resistance in pack ice condition between with a refrigerated ice and a synthetic ice. Model tests with a refrigerated ice have been conducted at Institute for Ocean Technology (IOT/NRC) and the tests with a synthetic ice were conducted at Pusan National University towing tank. For the validation of further tests of measurement and accuracy, the open water tests were first carried out with same model ship to compare the test results of both Institutes. Two different size of the wax-type synthetic ice were used and tests were conducted in pack ice of three different concentration ice conditions. The test results show that the difference of resistance between with synthetic and with refrigerated ice becomes larger according to the increase of ship speed. Although the quantity of resistance difference is not so small in high speed range, the present study is predicted to be used as a useful correlation between synthetic and refrigerated ice.

A Study on Modeling Metadata and Developing Standard Elements to Establish Oral History Archives (구술사 기록물 아카이브 구축을 위한 메타데이터 모델링 및 표준 요소 개발에 관한 연구)

  • Lee, Jung-Yeoun
    • Journal of the Korean Society for information Management
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    • v.26 no.1
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    • pp.163-184
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    • 2009
  • This study is aimed to develop standard metadata model and develop elements and present the importance of oral history archives that contrast with literature history. The study analyzed standard metadata description elements that can express contents and forms of oral history archives as information. Furthermore, it designed Project, Management, Record, and metadata modeling as a Related record domain for the sake of building digital oral archives. Finally, the study gave shape to real oral history archives based on basic elements, details, and design principles of division elements.

An Exploratory Study on the Effect of Weather Factors on Sales of Fashion Apparel Products in Department Stores (백화점 패션의류제품에 있어 기상요인이 매출에 미치는 영향에 대한 탐색적 연구)

  • Jang, Eun-Young;Lim, Byung-Hoon
    • Journal of Global Scholars of Marketing Science
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    • v.12
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    • pp.121-134
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    • 2003
  • Weather marketing is firms' effort to incorporate changes of diverse weather factors into marketing planning and activities. The concept has already been applied in many products with mostly seasonal variation. However researches in this area have been limited only in practical areas and has not been supported by scientifIc approaches. Here, we investigated the effect of diverse weather factors like temperature, rain and wind on product sales based on empirical data and scientifIc methodology. For this, we selected the fashion clothing items in department stores. We tried to fInd the relationship between daily sales of clothing items and daily whether factors. Results showed that there is a meaningful relation between the two factors.

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Particle-based Numerical Simulation of Continuous Ice Breaking Process around Wedge-type Model Ship (쐐기형 모형선 주위 연속 쇄빙과정에 관한 입자 기반 수치 시뮬레이션)

  • Ren, Di;Sin, Woo-Jin;Kim, Dong-Hyun;Park, Jong-Chun;Jeong, Seong-Yeob
    • Journal of the Society of Naval Architects of Korea
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    • v.57 no.1
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    • pp.23-34
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    • 2020
  • This paper covers the development of prediction techniques for ice load on ice-breakers operating in continuous ice-breaking under level ice conditions using particle-based continuum mechanics. Ice is assumed to be a linear elastic material until the fracture occurs. The maximum normal stress theory is used for the criterion of fracture. The location of the crack can be expressed using a local scalar function consisting of the gradient of the first principal stress and the corresponding eigen-vector. This expression is used to determine the relative position of particle pair to the new crack. The Hertz contact model is introduced to consider the collisions between ice fragments and the collisions between hull and ice fragments. In order to verify the developed technique, the simulation results for the three-point bending problems of ice-specimen and the continuous ice-breaking problem around a wedge-type model ship with bow angle of 20° are compared with the experimental results carrying out at Korea Research Institute of Ships and Ocean Engineering (KRISO).

A Model for the Development and Operation of Research Evaluation Services in Academic Libraries in Korea (국내 대학도서관 연구성과 서비스 개발 및 운영 모형 연구)

  • Kim, Soojung;Lee, Jae Yun;Lee, Ji-Won
    • Journal of the Korean Society for information Management
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    • v.38 no.3
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    • pp.287-309
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    • 2021
  • This study describes the introduction, growth, current practices and future plans of research evaluation services performed in domestic academic libraries, with a view to informing other libraries considering similar endeavours. To that end, in-depth interviews were conducted with four librarians from academic libraries leading in research evaluation services. The contents of the interviews were grouped into five categories including growth, management, and services. The study found that their research evaluation services were launched around 2010 by demands of members of a university or as a library's initiative to expand the existing services for the purpose of enhancing the university's research competitiveness. The research evaluation services have been strengthened by extending the service scope and improving related systems. Also, the study suggests a comprehensive model that can guide the development and operation of research evaluation services.

Analysis of Archive Service Quality Dimensions of National Archives of Korea for Applying Quality Function Deployment (QFD) (품질기능전개(QFD) 적용을 위한 국가기록원 기록정보서비스 품질 차원 분석)

  • Lee, Su Jin;Oh, Hyo-Jung
    • Proceedings of Korean Society of Archives and Records Management
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    • 2019.05a
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    • pp.35-41
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    • 2019
  • Providing efficient recording information services has become vital in a utilization-oriented records management environment and further increasing the importance of the quality of the services offered. This study is a preliminary study to propose improvement measures by applying Quality Function Development (QFD), a quality control method, to the National Archives of Korea (NAK) and Records Information Service. The quality dimensions of the recording information service were analyzed, and specific user requirements were derived. Through this process, the user requirements' questionnaire was developed, reflecting the characteristics of the NAK, and the application model of QFD was designed based on its prior study. Based on the QFD application model proposed, the results obtained by performing the QFD step by step can be expressed in House of Quality (HoQ), which can be used as a basis for service design.

On hydraulic characteristic analysis of landslide tsunami (산사태 지진해일의 수리특성 분석에 관한 고찰)

  • Seo, Minjang;Lee, Changmin;Lee, Woo-Dong
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.203-203
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    • 2022
  • 일반적으로 지진해일은 지진, 화산에 의한 융기 또는 침강에 따른 급작스러운 해저지각 운동에 의해 발생하며, 이에 따른 수위변동과 유체운동을 일컫는다. 그 밖에 해안/해저 산사태, 운석 낙하, 빙하 붕괴와 같이 암석, 토사, 얼음, 운석이 바다, 호수의 수면과 충돌하여 해일이 발생하기도 한다. 이 산사태 해일의 피해사례는 많지 않지만, 대부분 인명피해를 동반한다. 이에 과거부터 수리모형실험을 통해 산사태로 생성된 해일의 전파과정을 조사하는 연구들이 수행되었다. 최근에는 컴퓨터 성능향상과 다양한 수치모델이 개발됨에 따라 수치해석이 많이 수행되고 있다. 그러나 산사태 해일의 생성을 직접 모의하기 위해서는 유체-구조 상호작용(FSI; fluid-structure interaction)을 고려할 수 있는 전산유체역학(CFD; computational fluid dynamics)해석이 요구되는 관계로 활발한 연구가 진행되지 않고 있다. 본 연구에서는 FSI에 기초하여 충돌모의에 특화된 LS-DYNA를 이용하여 산사태 해일의 생성, 전파 그리고 직립벽(댐)에서의 처오름 및 파압 등을 검토한다. 그리고 낙하물의 형상, 낙하 높이에 따라 생성된 해일이 댐에 미치는 영향을 분석한다. 또한, 이용하는 LS-DYNA 해석의 타당성 및 유효성을 확인하기 위하여 기존 수리모형실험에서 생성된 산사태 지진해일과 비교·검증한다. 수치해석 결과, 동일한 체적의 낙하물에서는 폭이 좁을수록 최대파고가 낙하물에 근접해 생성되었고, 폭이 넓을수록 파장이 길어지는 것을 확인할 수 있었다. 낙하물의 낙하높이가 높을수록 산사태 지진해일의 파고가 크게 생성되었다. 낙하물로부터 600m 지점에서 설치한 댐에서의 산사태 지진해일의 처오름은 파고 및 파장이 클수록 증가하였다. 산사태 지진해일의 파압 역시 처오름에 상응하게 나타났다. 그러므로 호소에서 산사태 해일이 발생한다면, 댐 및 제방의 안정성에 영향을 미칠 수 있을 것으로 판단된다.

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A Quality-control Experiment Involving an Optical Televiewer Using a Fractured Borehole Model (균열모형시추공을 이용한 광학영상화검층 품질관리 시험)

  • Jeong, Seungho;Shin, Jehyun;Hwang, Seho;Kim, Ji-Soo
    • The Journal of Engineering Geology
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    • v.30 no.1
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    • pp.17-30
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    • 2020
  • An optical televiewer is a geophysical logging device that produces continuous high-resolution full-azimuth images of a borehole wall using a light-emitting-diode and a complementary metal-oxide semiconductor image sensor to provide valuable information on subsurface discontinuities. Recently, borehole imaging logging has been applied in many fields, including ground subsidence monitoring, rock mass integrity evaluation, stress-induced fracture detection, and glacial annual-layer measurements in polar regions. Widely used commercial borehole imaging logging systems typically have limitations depending on equipment specifications, meaning that it is necessary to clearly verify the scope of applications while maintaining appropriate quality control for various borehole conditions. However, it is difficult to directly check the accuracy, implementation, and reliability for outcomes, as images derived from an optical televiewer constitute in situ data. In this study, we designed and constructed a modular fractured borehole model having similar conditions to a borehole environment to report unprecedented results regarding reliable data acquisition and processing. We investigate sonde magnetometer accuracy, color realization, and fracture resolution, and suggest data processing methods to obtain accurate aperture measurements. The experiment involving the fractured borehole model should enhance not only measurement quality but also interpretations of high-resolution and reliable optical imaging logs.

A Proposal for the Acceptance and Processes of Open Access in Korean Societies (국내 학회의 오픈액세스 수용과 추진방식에 대한 제안)

  • Kim, Gyuhwan
    • Journal of the Korean Society for information Management
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    • v.31 no.3
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    • pp.111-131
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    • 2014
  • The purpose of this study was to propose a guide for the acceptance and processes of open access in Korean Societies. Firstly, this study developed journal publishers' open access model focused on the relationship between types and strategies of open access. Secondly, this study investigated current status of journal publishers' open access strategies and the adoption degrees through SHERPA/RoMEO, DOAJ and PMC databases. Finally, on the basis of the result, this study proposed a guide to help Korean societies make journals more open or less open according to their situations as real. Korean societies can make informed decisions about how to derive open access.