• Title/Summary/Keyword: Knowledge Structures

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Pushover Analysis of Reinforced Concrete Wall-Frame Structures Using Equivalent Column Model (등가 기둥 모델을 이용한 철근콘크리트 전단벽-골조 구조물의 푸쉬오버 해석)

  • Kim, Yong Joon;Han, Arum;Kim, Seung Nam;Yu, Eunjong
    • Journal of the Earthquake Engineering Society of Korea
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    • v.18 no.1
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    • pp.53-61
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    • 2014
  • RC shear wall sections which have irregular shapes such as T, ㄱ, ㄷ sections are typically used in low-rise buildings in Korea. Pushover analysis of building containing such members costs a lot of computation time and needs professional knowledge since it requires complicated modeling and, sometimes, fails to converge. In this study, a method using an equivalent column element for the shear wall is proposed. The equivalent column element consists of an elastic column, an inelastic rotational spring, and rigid beams. The inelastic properties of the rotational spring represent the nonlinear behavior of the shearwall and are obtained from the section analysis results and moment distribution for the member. The use of an axial force to compensate the difference in the axial deformation between the equivalent column element and the actual shear wall is also proposed. The proposed method is applied for the pushover analysis of a 5- story shear wall-frame building and the results are compared with ones using the fiber elements. The comparison shows that the inelastic behavior at the same drift was comparable. However, the performance points estimated using the pushover curves showed some deviations, which seem to be caused by the differences of estimated yield point and damping ratios.

Predicting the stiffness of shear diaphragm panels composed of bridge metal deck forms

  • Egilmez, Oguz O.
    • Steel and Composite Structures
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    • v.24 no.2
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    • pp.213-226
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    • 2017
  • The behavior of building industry metal sheeting under shear forces has been extensively studied and equations have been developed to predict its shear stiffness. Building design engineers can make use of these equations to design a metal deck form bracing system. Bridge metal deck forms differ from building industry forms by both shape and connection detail. These two factors have implications for using these equations to predict the shear stiffness of deck form systems used in the bridge industry. The conventional eccentric connection of bridge metal deck forms reduces their shear stiffness dramatically. However, recent studies have shown that a simple modification to the connection detail can significantly increase the shear stiffness of bridge metal deck form panels. To the best of the author's knowledge currently there is not a design aid that can be used by bridge engineers to estimate the stiffness of bridge metal deck forms. Therefore, bridge engineers rely on previous test results to predict the stiffness of bridge metal deck forms in bracing applications. In an effort to provide a design aid for bridge design engineers to rely on bridge metal deck forms as a bracing source during construction, cantilever shear frame test results of bridge metal deck forms with and without edge stiffened panels have been compared with the SDI Diaphragm Design Manual and ECCS Diaphragm Stressed Skin Design Manual stiffness expressions used for building industry deck forms. The bridge metal deck form systems utilized in the tests consisted of sheets with thicknesses of 0.75 mm to 1.90 mm, heights of 50 mm to 75 mm and lengths of up to 2.7 m; which are representative of bridge metal deck forms frequently employed in steel bridge constructions. The results indicate that expressions provided in these manuals to predict the shear stiffness of building metal deck form panels can be used to estimate the shear stiffness of bridge metal deck form bracing systems with certain limitations. The SDI Diaphragm Design Manual expressions result in reasonable estimates for sheet thicknesses of 0.75 mm, 0.91 mm, and 1.21 mm and underestimate the shear stiffness of 1.52 and 1.90 mm thick bridge metal deck forms. Whereas, the ECCS Diaphragm Stressed Skin Design Manual expressions significantly underestimate the shear stiffness of bridge metal deck form systems for above mentioned deck thicknesses.

A Study on Book Reviews for Further Readings (심화독서용 서평에 관한 연구)

  • Min, Kyeong-Rok
    • Journal of the Korean Society for Library and Information Science
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    • v.52 no.3
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    • pp.35-59
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    • 2018
  • A book review expands readers' choice of resources by providing them with the contents and bibliographic data of various books. It also functions as a reader support service designed to enrich their reading experiences. In particular, in the field of children's reading, literary devices are used to convey knowledge and information to children. Therefore, a review for a children's book should help children follow a book with further readings so that they can expand their literary imagination through comparative reading. In light of the above, this study looks into the case of a children's story entitled Little Red Riding Hood to identify the points that should be addressed in the "Literature Comparison" section of a book review in order to suggest further readings to readers. First, the review should provide an objective description of the content of Little Red Riding Hood. Second, it should explain the literary value of the reviewed book and the discourse that surrounds it so as to analyze its unique features that separate it from other literary works. Third, the review should provide bibliographic information on other works that use narrative structures adapted from those of Little Red Riding Hood. Fourth, it should broaden readers' choice and access by introducing, if any, works adapted from Little Red Riding Hood into other media.

Numerical and Experimental Investigations of Dynamic Stall

  • Geissler, Wolfgang;Raffel, Markus;Dietz, Guido;Mai, Holger
    • 한국전산유체공학회:학술대회논문집
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    • 2009.04a
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    • pp.19-19
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    • 2009
  • Dynamic Stall is a flow phenomenon which occurs on the retreating side of helicopter rotor blades during forward flight. It also occurs on blades of stall regulated wind turbines under yawing conditions as well as during gust loads. Time scales occurring during this process are comparable on both helicopter and wind turbine blades. Dynamic Stall limits the speed of the helicopter and its manoeuvrability and limits the amount of power production of wind turbines. Extensive numerical as well as experimental investigations have been carried out recently to get detailed insight into the very complex flow structures of the Dynamic Stall process. Numerical codes have to be based on the full equations, i.e. the Navier-Stokes equations to cover the scope of the problems involved: Time dependent flow, unsteady flow separation, vortex development and shedding, compressibility effects, turbulence, transition and 3D-effects, etc. have to be taken into account. In addition to the numerical treatment of the Dynamic Stall problem suitable wind tunnel experiments are inevitable. Comparisons of experimental data with calculated results show us the state of the art and validity of the CFD-codes and the necessity to further improve calculation procedures. In the present paper the phenomenon of Dynamic Stall will be discussed first. This discussion is followed by comparisons of some recently obtained experimental and numerical results for an oscillating helicopter airfoil under Dynamic Stall conditions. From the knowledge base of the Dynamic Stall Problems, the next step can be envisaged: to control Dynamic Stall. The present discussion will address two different Dynamic Stall control methodologies: the Nose-Droop concept and the application of Leading Edge Vortex Generators (LEVoG's) as examples of active and passive control devices. It will be shown that experimental results are available but CFD-data are only of limited comparison. A lot of future work has to be done in CFD-code development to fill this gap. Here mainly 3D-effects as well as improvements of both turbulence and transition modelling are of major concern.

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Organized Hematoma in the Maxillary Sinus (상악동에 발생한 organized hematoma)

  • Kim, Jae-Jin
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.32 no.5
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    • pp.473-477
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    • 2010
  • Organized hematoma of the maxillary sinus is a rare, nonneoplastic benign lesion with locally destructive behavior that may mimic a malignancy. Clinically, symptoms do not usually occur while the lesion remains localized to the maxillary sinus. Because there is gradual enlargement of the lesion causing erosion and displacement of the adjacent bony structures, symptoms such as epistaxis, cheek swelling, nasal obstruc-tion, headache, and exophthalmos become manifest. Radiologically, unilateral cases are much more fre-quent than bilateral, and Waters' view shows complete opacity of the expanded maxillary sinus and some masses. CT scan shows a large heterogeneous enhancing mass causing considerable expansion of the max-illary sinus with bony erosion. On MR imaging, the mass usually has a variable signal intensity on T1- and T2- weighted images, ranging from low to high. After contrast administration, discrete areas of enhance-ment are present within the mass. Although the disease is essentially benign and nonneoplastic, differen-tial diagnosis from neoplastic disease including malignancy both clinically and radiologically has been always problematic. Accurate preoperative diagnosis of organized hematoma of the maxillary sinus is important to avoid unnecessary extensive surgery, because this condition is curative with a simple, conservative surgical approach and rarely recur. Organized hematoma of the maxillary sinus should be included in the differential diagnosis when patients have recurrent epistaxis, slow-growing mass of the cheek, nasal obstruction, and expansile mass in the maxillary sinus. A 33-year-old man was referred to the department of oral and maxillofacial surgery with a three-month history of slowly growing painful swelling of the left cheek. The mass of the maxillary sinus was resected by a Caldwell-Luc approach. Histopahtoly showed only a fibous encapsulated organized hematoma. To our knowledge, organized hematoma of the maxillary sinus has not been previously described in the Korean literature of the oral and maxillofacial surgery. We report a case of organized hematoma of the maxillary sinus presenting with an enlarging maxillary sinus mass.

An Explorative Analysis of Hypothesis-Generation by Pre-service Science Teachers (예비 과학교사들의 가설 창안 과정에 대한 탐색적 분석)

  • Kwon, Yong-Ju;Yang, II-Ho;Chung, Won-Woo
    • Journal of The Korean Association For Science Education
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    • v.20 no.1
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    • pp.29-42
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    • 2000
  • Hypothesis is defined as a single proposition proposed as a possible explanation for the occurrence of some observed phenomena. The purpose of this study was to analyze and categorize hypotheses generated by students on the cause of difference between the structures of muscles of the fishes and the terrestrial animals. A hypothesis-generating test was administered to 23 three college students who were majoring in science education. The study showed that college students generated manipulative and theoretical hypotheses as proposed explanations for the structural difference between muscles of the fishes and the terrestrial animals. Furthermore, students generated several hypotheses which were categorized by the quality of abductive process based on the degree of likeness between experienced knowledge and current phenomena. This study also discusses the implications of these findings for teaching and research in science education.

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Collaboration Framework based on Social Semantic Web for Cloud Systems (클라우드 시스템에서 소셜 시멘틱 웹 기반 협력 프레임 워크)

  • Mateo, Romeo Mark A.;Yang, Hyun-Ho;Lee, Jae-Wan
    • Journal of Internet Computing and Services
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    • v.13 no.1
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    • pp.65-74
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    • 2012
  • Cloud services are used for improving business. Moreover, customer relationship management(CRM) approaches use social networking as tools to enhance services to customers. However, most cloud systems do not support the semantic structures, and because of this, vital information from social network sites is still hard to process and use for business strategy. This paper proposes a collaboration framework based on social semantic web for cloud system. The proposed framework consists of components to support social semantic web to provide an efficient collaboration system for cloud consumers and service providers. The knowledge acquisition module extracts rules from data gathered by social agents and these rules are used for collaboration and business strategy. This paper showed the implementations of processing of social network site data in the proposed semantic model and pattern extraction which was used for the virtual grouping of cloud service providers for efficient collaboration.

An Activation Plan for Make-up Illustration Education (메이크업 일러스트레이션 교육 활성화 방안)

  • Kim, Kyung-Tai;Choi, Keun-Hee
    • Journal of the Korean Society of Fashion and Beauty
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    • v.4 no.3 s.9
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    • pp.5-12
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    • 2006
  • Make-up illustration is a field of creativity with visible creative and artistic values; its ultimate functions include communication of information, artistic expression, and recording. Establishing the make-up illustration education environment for the twenty-first century, there is an urgent need for research and development of professional curricula for basic art education and illustration education. It is extremely important for educators and institutions teaching make-up illustration to recognize that training of highly creative and professional beau designers through systematic educational structures is the ultimate foundation for enhancing competitiveness of the beauty industry despite the present reality that there are insufficient studies and publications on beauty illustration and that there is lack of illustration lecturers and artists equipped with professional beauty knowledge. Therefore, this study was conducted to research and analyze offering of illustration subjects by 160 beauty-related vocational schools and 16 4-year undergraduate colleges in the make-up field, which is the field with most creative art activities among the three representative beauty majors, namely make-up, hair, and skin. Education of make-up illustration must not remain as simple short-term education. The curricula must be specialized for providing solid foundation of basic majors. In terms of education content, strong emphases must be made for original and creative mark-up designs as well as purposes, functions, and necessity of make-up design and illustration. The curricula must include systematic, logical and artistic elements. Through the course of this study, which researched, analyzed and proposed measures for education content of make-up illustration, it was found that make-up illustration is the most appropriate subject that fulfills both the ultimate education objectives of beauty colleges and the demand by the society for beauty professionals. It is hoped that make-up illustration is emphasized and recognized for its importance and necessity as an education subject so that similar basic major subjects will further be researched and developed for specialized education.

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The Automatic Management of Classification Scheme with Interoperability on Heterogeneous Data (이기종 데이터 간 상호운용적 분류체계 관리를 위한 분류체계 자동화 방안)

  • Lee, Won-Goo;Hwang, Myung-Gwon;Lee, Min-Ho;Shin, Sung-Ho;Kim, Kwang-Young;Yoon, Hwa-Mook;Sung, Won-Kyung;Jeon, Do-Heon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.12
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    • pp.2609-2618
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    • 2011
  • Under the knowledge-based economy in 21C, the convergence and complexity in science and technology are being more active. Interoperability between heterogeneous domains is a very important point considered in the field of scholarly information service as well information standardization. Thus we suggest the systematic solution method to flexibly extend classification scheme in order for content management and service organizations. Especially, This paper shows that automatic method for interoperability between heterogeneous scholarly classification code structures will be effective in enhancing the information service system.

Assessment of the Dynamics of Microbial Community Associated with Tetraselmis suecica Culture under Different LED Lights Using Next-Generation Sequencing

  • Yang, Su-Jeong;Kim, Hyun-Woo;Choi, Seok-Gwan;Chung, Sangdeok;Oh, Seok Jin;Borkar, Shweta;Kim, Hak Jun
    • Journal of Microbiology and Biotechnology
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    • v.29 no.12
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    • pp.1957-1968
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    • 2019
  • Tetraselmis is a green algal genus, some of whose species are important in aquaculture as well as biotechnology. In algal culture, fluorescent lamps, traditional light source for culturing algae, are now being replaced by a cost-effective light-emitting diodes (LEDs). In this study, we investigated the effect of LED light of different wavelengths (white, red, yellow, and blue) on the growth of Tetraselmis suecica and its associated microbial community structures using the next-generation sequencing (NGS). The fastest growth rate of T. suecica was shown in the red light, whereas the slowest was in yellow. The highest OTUs (3426) were identified on day 0, whereas the lowest ones (308) were found on day 15 under red light. The top 100 OTUs associated with day 0 and day 5 cultures of T. suecica under the red and yellow LED were compared. Only 26 OTUs were commonly identified among four samples. The highest numbers of unique OTUs were identified at day 0, indicating the high degree of initial microbial diversity of the T. suecica inoculum. The red light-unique OTUs occupied 34.98%, whereas the yellow-specific OTUs accounted for only 2.2%. This result suggested a higher degree of interaction in T. suecica culture under the red light, where stronger photosynthesis occurs. Apparently, the microbial community associated with T. suecica related to the oxygen produced by algal photosynthesis. This result may expand our knowledge about the algae-bacteria consortia, which would be useful for various biotechnological applications including wastewater treatment, bioremediation, and sustainable aquaculture.