• Title/Summary/Keyword: Content element analysis

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Analysis of axial compression performance of BFRRAC-filled square steel tubular column

  • Xianggang Zhang;Jixiang Niu;Wenlong Shen;Dapeng Deng;Yajun Huang
    • Steel and Composite Structures
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    • v.49 no.4
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    • pp.457-471
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    • 2023
  • To make up for the performance weaknesses of recycled aggregate concrete (RAC), expand the application range of RAC, and alleviate the environmental problems caused by excessive exploitation of natural coarse aggregates (NCA), this study proposes a basalt fiber-reinforced recycled aggregate concrete (BFRRAC)-filled square steel tubular columns that combines two modification methods of steel tube and fiber, which may greatly enhance the mechanical properties of RAC. The axial compression performance for BFRRAC-filled square steel tubular columns was reported during this study. Seven specimens with different replacement ratios of recycled coarse aggregate (RCA), length-diameter ratios, along with basalt fiber (BF) contents were designed as well as fabricated for performing axial compression test. For each specimen, the whole failure process as well as mode of specimen were discovered, subsequently the load-axial displacement curve has obtained, after which the mechanical properties was explained. A finite element analysis model for specimens under axial compression was then established. Subsequently, based on this model, the factors affecting axial compression performance for BFRRAC-filled square steel tubes were extended and analyzed, after which the corresponding design suggestion was proposed. The results show that in the columns with length-diameter ratios of 5 and 8, bulging failure was presented, and the RAC was severely crushed at the bulging area of the specimen. The replacement ratio of RCA as well as BF content little affected specimen's peak load (less than 5%). As the content of BF enhanced from 0 kg/m3 to 4 kg/m3, the dissipation factor and ductility coefficients increased by 10.2% and 5.6%, respectively, with a wide range.

Evaluation on Applicability of Finite Element Analysis in Model Test of Pile Pullout (말뚝 인발모형실험에 대한 유한요소해석의 적용성 평가)

  • You, Seung-Kyong;Shin, Heesoo;Lee, Kwang-Wu;Park, Jeong-Jun;Choi, Choong-Lak;Hong, Gigwon
    • Journal of the Korean Geosynthetics Society
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    • v.18 no.2
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    • pp.11-21
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    • 2019
  • This paper describes the applicability of FEA(Finite Element Analysis) to the simulation of pile pullout behavior under various soil conditions (relative density and fines content), in order to evaluate reasonably the pullout resistance of pile. That is, the results of previous research (You et al., 2018) were analyzed by FEA under the same conditions. The FEA results showed that axisymmetric analysis using virtual ground was able to evaluate the skin friction of the pile. Also, axisymmetric analysis, which can apply the shear resistance characteristics of the pile-soil interface in various soil conditions, could be used as an analytical method that can simulate a reasonable pile pullout behavior. Therefore, the analytical model proposed in this study was able to simulate appropriately the pullout behavior based on the stress-strain relationship of the pile-soil interface.

Numerical Study of Unsaturated Infinite Slope Stability regarding Suction Stress under Rainfall-induced Infiltration Conditions

  • Song, Young-Suk;Hwang, Woong-Ki
    • The Journal of Engineering Geology
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    • v.24 no.1
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    • pp.1-8
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    • 2014
  • Numerical stability analysis of an unsaturated infinite slope under rainfall-induced infiltration conditions was performed using generalized effective stress to unify both saturated and unsaturated conditions The soil-water characteristic curve (SWCC) of sand with a relative density of 75% was initially measured for both drying and wetting processes. The hydraulic conductivity function (HCF) and suction stress characteristic curve (SSCC) were subsequently estimated. Under the rainfall-induced infiltration conditions, transient seepage analysis of an unsaturated infinite slope was performed using the finite element analysis program, SEEP/W. Based on these results, the stability of an unsaturated infinite slope under rainfall-induced infiltration conditions was examined in relation to suction stress. According to the results, the negative pore-water pressure and water content within the slope soil changed over time due to the infiltration. In addition, the variation of the negative pore-water pressure and water content led to a variation in suction stress and a subsequent change in the slope's factor of safety during the rainfall period.

A cohesive model for concrete mesostructure considering friction effect between cracks

  • Huang, Yi-qun;Hu, Shao-wei
    • Computers and Concrete
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    • v.24 no.1
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    • pp.51-61
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    • 2019
  • Compressive ability is one of the most important mechanical properties of concrete material. The compressive failure process of concrete is pretty complex with internal tension, shear damage and friction between cracks. To simulate the complex fracture process of concrete at meso level, methodology for meso-structural analysis of concrete specimens is developed; the zero thickness cohesive elements are pre-inserted to simulate the crack initiation and propagation; the constitutive applied in cohesive element is established to describe the mechanism of crack separation, closure and friction behavior between the fracture surfaces. A series of simulations were carried out based on the model proposed in this paper. The results reproduced the main fracture and mechanical feature of concrete under compression condition. The effect of key material parameters, structure size, and aggregate content on the concrete fracture pattern and loading carrying capacities was investigated. It is found that the inner friction coefficient has a significant influence on the compression character of concrete, the compression strength raises linearly with the increase of the inner friction coefficient, and the fracture pattern is sensitive to the mesostructure of concrete.

Dynamic stability evaluation of nail stabilised vertical cuts in various site classes

  • Amrita;B.R. Jayalekshmi;R. Shivashankar
    • Geomechanics and Engineering
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    • v.38 no.4
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    • pp.421-437
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    • 2024
  • The soil nailing method entails the utilisation of nails to reinforce and stabilise a zone of soil mass. This is widely used for various applications due to its effective performance under various loading conditions. The seismic response of 6m high vertical soil-nailed cut in various site classes under dynamic excitations has been investigated in this study considering various lengths and inclinations of nails. The influence of frequency content of dynamic excitation on the response of structure has been assessed through finite element analysis using time history data of three different earthquakes. The seismic stability of the nailed cut in retaining soil in various sites under El Centro, Kobe and Trinidad earthquake ground motion is evaluated based on maximum acceleration response, maximum horizontal deformation, earth pressure distribution on the wall and maximum axial force mobilised in nails. The optimum nail inclination is identified as 15° and a minimum nail length ratio of 0.7 is essential for a stable vertical cut under dynamic excitations.

A Study on the Creation Method of Cultural Content - TRIZ Training using Folklore Edutainment - (문화콘텐츠 창작방법 연구 - 민담 에듀테인먼트를 활용한 트리즈교육 -)

  • Lee, Myoungja
    • The Journal of the Convergence on Culture Technology
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    • v.6 no.2
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    • pp.91-98
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    • 2020
  • In this paper, the creation method of edutainment content among cultural content types was studied. Edutainment aimed to enhance the creative thinking power through the "TRIZ theory" as an element of fun and education for learners at the same time. In this study, the modified OSTM-TRIZ theory was used not only in the technical field but also in the general sector. I proposed a model in which creative thinking can be enhanced to solve problems by analyzing contradictions encountered in the process of presenting problems. Nonlinear digital storytelling in animated folktales can elicit sufficient curiosity from learners, and problem presentation, problem resolution and contradiction analysis using OTSM-TRIZ work as an educational system to develop learners' creativity.

Nonlinear Structural Safety Assessment under Dynamic Excitation Using SFEM (추계론적 유한 요소법을 이용한 동하중을 받는 비선형 구조물의 안전성 평가)

  • Huh, Jungwon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.13 no.3
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    • pp.373-384
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    • 2000
  • To assess the safety of nonlinear steel frame structures subjected to short duration dynamic loadings, especially seismic loading, a nonlinear time domain reliability analysis procedure is proposed in the context of the stochastic finite element concept. In the proposed algorithm, the finite element formulation is combined with concepts of the response surface method, the first order reliability method, and the iterative linear interpolation scheme. This leads to the stochastic finite element concept. Actual earthquake loading time-histories are used to excite structures, enabling a realistic representation of the loading conditions. The assumed stress-based finite element formulation is used to increase its efficiency. The algorithm also has the potential to evaluate the risk associated with any linear or nonlinear structure that can be represented by a finite element algorithm subjected to seismic loading or any short duration dynamic loading. The algorithm is explained with help of an example and verified using the Monte Carlo simulation technique.

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An Analysis of Fields and Scientific Literacy Content Elements of Scientific Reports in a Popular Portal Site in Korea (국내 포탈사이트 과학 기사 분야와 과학적 소양 내용 요소 분석)

  • Lee, Myeong-Je
    • Journal of Korean Elementary Science Education
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    • v.34 no.3
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    • pp.338-345
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    • 2015
  • The purpose of this study is to analyze science fields and content elements of the science reports in a web portal site of Republic of Korea in view of scientific literacy. The main results of the analysis on the 679 reports sampled in a year are as follows. First, 506 reports in 46 fields were identified. Reports about technology and earth science occupies 16% respectively, and life science occupies 13%, medical science 4%, chemistry, company, others 3% and physics 1%. Almost reports show technology as associate field. Second, the frequency rate of reports including scientific literacy content elements is 52%. Reports related to 'physics' and 'chemistry' as dominant fields show relatively high rate in scientific literacy elements. The element, 'social context' is included in about 96% of the reports. Both 'data and statistics' and 'application' show relatively low rate and large gaps according to dominant fields. A few concluding remarks and proposals follow from these results. First, as almost science reports show the nature of integrated science, scientific literacy acquisition through science reports in internet requires the integrated scientific view. Especially most science reports includes the contents related to technology or medical science, so the point of view in the science-technological literacy is required. Second, the scientific literacy content elements in reports show various rates according to dominant fields. Therefore, science reports need to complement the deficient content elements to carry out the role of science reports as scientific literacy sources.

Story-based Information Retrieval (스토리 기반의 정보 검색 연구)

  • You, Eun-Soon;Park, Seung-Bo
    • Journal of Intelligence and Information Systems
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    • v.19 no.4
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    • pp.81-96
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    • 2013
  • Video information retrieval has become a very important issue because of the explosive increase in video data from Web content development. Meanwhile, content-based video analysis using visual features has been the main source for video information retrieval and browsing. Content in video can be represented with content-based analysis techniques, which can extract various features from audio-visual data such as frames, shots, colors, texture, or shape. Moreover, similarity between videos can be measured through content-based analysis. However, a movie that is one of typical types of video data is organized by story as well as audio-visual data. This causes a semantic gap between significant information recognized by people and information resulting from content-based analysis, when content-based video analysis using only audio-visual data of low level is applied to information retrieval of movie. The reason for this semantic gap is that the story line for a movie is high level information, with relationships in the content that changes as the movie progresses. Information retrieval related to the story line of a movie cannot be executed by only content-based analysis techniques. A formal model is needed, which can determine relationships among movie contents, or track meaning changes, in order to accurately retrieve the story information. Recently, story-based video analysis techniques have emerged using a social network concept for story information retrieval. These approaches represent a story by using the relationships between characters in a movie, but these approaches have problems. First, they do not express dynamic changes in relationships between characters according to story development. Second, they miss profound information, such as emotions indicating the identities and psychological states of the characters. Emotion is essential to understanding a character's motivation, conflict, and resolution. Third, they do not take account of events and background that contribute to the story. As a result, this paper reviews the importance and weaknesses of previous video analysis methods ranging from content-based approaches to story analysis based on social network. Also, we suggest necessary elements, such as character, background, and events, based on narrative structures introduced in the literature. We extract characters' emotional words from the script of the movie Pretty Woman by using the hierarchical attribute of WordNet, which is an extensive English thesaurus. WordNet offers relationships between words (e.g., synonyms, hypernyms, hyponyms, antonyms). We present a method to visualize the emotional pattern of a character over time. Second, a character's inner nature must be predetermined in order to model a character arc that can depict the character's growth and development. To this end, we analyze the amount of the character's dialogue in the script and track the character's inner nature using social network concepts, such as in-degree (incoming links) and out-degree (outgoing links). Additionally, we propose a method that can track a character's inner nature by tracing indices such as degree, in-degree, and out-degree of the character network in a movie through its progression. Finally, the spatial background where characters meet and where events take place is an important element in the story. We take advantage of the movie script to extracting significant spatial background and suggest a scene map describing spatial arrangements and distances in the movie. Important places where main characters first meet or where they stay during long periods of time can be extracted through this scene map. In view of the aforementioned three elements (character, event, background), we extract a variety of information related to the story and evaluate the performance of the proposed method. We can track story information extracted over time and detect a change in the character's emotion or inner nature, spatial movement, and conflicts and resolutions in the story.

Determination of Trace Metals in Fel Ursi (시판 웅담의 미량금속 정량에 관한 연구)

  • Lee, Sook-Yun;Yu, Bong-Shin;Mun, Hye-Ryoung;Kim, Sung-Kyung
    • Korean Journal of Pharmacognosy
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    • v.13 no.3
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    • pp.102-105
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    • 1982
  • Nine trace elements in Bear Galls(Fel Ursi) studied in this paper are Na, Mg, K, Ca, Cu, Zn, Fe, Pb and Ge. The contents of Na, Mg, K, Ca, Cu, Zn, Fe, Pb are determined by atomic absorption spectrometry and Ge is determined by graphite atomic absorption spectrometry. In both methods, the sample is digested with nitric-perchloric acid and then ashed. The results of analysis are shown in table and the result obtained from this study are as follows. a. The highest content of trace element of Bear Gall is Na and other elements are getting lower in order of K, Mg, Ca, Ge, Zn, Fe, Cu, and Pb. b. Particularly the content of Ge in Bear Gall was determined.

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