• Title/Summary/Keyword: key elements

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The Functional Requirements of Core Elements for Research Data Management and Service (연구 데이터 관리 및 서비스를 위한 핵심요소의 기능적 요건)

  • Kim, Juseop;Kim, Suntae;Choi, Sangki
    • Journal of the Korean Society for Library and Information Science
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    • v.53 no.3
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    • pp.317-344
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    • 2019
  • Increasing the value of data, paradigm shifts in research methods, and specific manifestations of open science indicate that research is no longer text-centric, but data-driven. In this study, we analyzed the services for DCC, ICPSR, ANDS and DataONE to derive key elements and functional requirements for research data management and services that are still insufficient in domestic research. Key factors derived include DMP writing support, data description, data storage, data sharing and access, data citations, and data management training. In addition, by presenting functional requirements to the derived key elements, this study can be applied to construct and operate RDM service in the future.

The elastoplastic formulation of polygonal element method based on triangular finite meshes

  • Cai, Yong-Chang;Zhu, He-Hua;Guo, Sheng-Yong
    • Structural Engineering and Mechanics
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    • v.30 no.1
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    • pp.119-129
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    • 2008
  • A small strain and elastoplastic formulation of Polygonal Element Method (PEM) is developed for efficient analysis of elastoplastic solids. In this work, the polygonal elements are constructed based on traditional triangular finite meshes. The construction method of polygonal mesh can directly utilize the sophisticated triangularization algorithm and reduce the difficulty in generating polygonal elements. The Wachspress rational finite element basis function is used to construct the approximations of polygonal elements. The incremental variational form and a von Mises type model are used for non-linear elastoplastic analysis. Several small strain elastoplastic numerical examples are presented to verify the advantages and the accuracy of the numerical formulation.

2-D meso-scale complex fracture modeling of concrete with embedded cohesive elements

  • Shen, Mingyan;Shi, Zheng;Zhao, Chao;Zhong, Xingu;Liu, Bo;Shu, Xiaojuan
    • Computers and Concrete
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    • v.24 no.3
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    • pp.207-222
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    • 2019
  • This paper has presented an effective and accurate meso-scale finite element model for simulating the fracture process of concrete under compression-shear loading. In the proposed model, concrete is parted into four important phases: aggregates, cement matrix, interfacial transition zone (ITZ), and the initial defects. Aggregate particles were modelled as randomly distributed polygons with a varying size according to the sieve curve developed by Fuller and Thompson. With regard to initial defects, only voids are considered. Cohesive elements with zero thickness are inserted into the initial mesh of cement matrix and along the interface between aggregate and cement matrix to simulate the cracking process of concrete. The constitutive model provided by ABAQUS is modified based on Wang's experiment and used to describe the failure behaviour of cohesive elements. User defined programs for aggregate delivery, cohesive element insertion and modified facture constitutive model are developed based on Python language, and embedded into the commercial FEM package ABAQUS. The effectiveness and accuracy of the proposed model are firstly identified by comparing the numerical results with the experimental ones, and then it is used to investigate the effect of meso-structure on the macro behavior of concrete. The shear strength of concrete under different pressures is also involved in this study, which could provide a reference for the macroscopic simulation of concrete component under shear force.

Automatic Generation of Triangular Ginite Element Meshes on Three-Dimensional Surfaces (3차원 곡면에서 삼각형 유한요소망의 자동생성)

  • 채수원;손창현
    • Korean Journal of Computational Design and Engineering
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    • v.1 no.3
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    • pp.224-233
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    • 1996
  • An automatic mesh generation scheme with triangular finite elements on three-dimensional surfaces has been developed. The surface triangulation process is performed as follows. To begin, surfaces with key nodes are transformed to two-dimensional planes and the meshes with triangular elements are constructed in these planes. Finally, the constructed meshes are transformed back to the original 3D surfaces. For the mesh generation, an irregular mesh generation scheme is employed in which local mesh densities are assigned by the user along the boundaries of the analysis domain. For this purpose a looping algorithm combined with an advancing front technique using basic operators has been developed, in which the loops are recursively subdivided into subloops with the use of the best split lines and then the basic operators generate elements. Using the split lines, the original boundaries are split recursively until each loop contains a certain number of key nodes, and then using the basic operators such as type-1 and type-2, one or two triangular elements are generated at each operation. After the triangulation process has been completed for each meshing domain, the resulting meshes are finally improved by smoothing process. Sample meshes are presented to demonstrate the versatility of the algorithm.

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Fast Sub-aperture Stitching Algorithm Using Partial Derivatives

  • Chen, Yiwei;Miao, Erlong;Sui, Yongxin;Yang, Huaijiang
    • Journal of the Optical Society of Korea
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    • v.19 no.1
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    • pp.84-87
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    • 2015
  • For large optical elements which are tested by many sub-apertures, it takes too much time for a sub-aperture stitching algorithm to get the stitching result. To solve this problem, we propose a fast sub-aperture stitching algorithm to quickly compensate for piston, tilt, and defocus errors. Moreover, the new algorithm is easy to understand and program. We use partial derivatives of measurement data to separately solve piston, tilt, and defocus errors. First, we show that the new algorithm has a lower time complexity than the currently used algorithm. Although simulation results indicate that the accuracy of the new algorithm is lower than the current algorithm in all 20 simulations, our experimental results validate the algorithm and show it is sufficiently accurate for general use.

Structural damage identification using an iterative two-stage method combining a modal energy based index with the BAS algorithm

  • Wang, Shuqing;Jiang, Yufeng;Xu, Mingqiang;Li, Yingchao;Li, Zhixiong
    • Steel and Composite Structures
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    • v.36 no.1
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    • pp.31-45
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    • 2020
  • The purpose of this study is to develop an effective iterative two-stage method (ITSM) for structural damage identification of offshore platform structures. In each iteration, a new damage index, Modal Energy-Based Damage Index (MEBI), is proposed to help effectively locate the potential damage elements in the first stage. Then, in the second stage, the beetle antenna search (BAS) algorithm is used to estimate the damage severity of these elements. Compared with the well-known particle swarm optimization (PSO) algorithm and genetic algorithm (GA), this algorithm has lower computational cost. A modal energy based objective function for the optimization process is proposed. Using numerical and experimental data, the efficiency and accuracy of the ITSM are studied. The effects of measurement noise and spatial incompleteness of mode shape are both considered. All the obtained results show that under these influences, the ITSM can accurately identify the true location and severity of damage. The results also show that the objective function based on modal energy is most suitable for the ITSM compared with that based on flexibility and weighted natural frequency-mode shape.

Structural damage identification based on genetically trained ANNs in beams

  • Li, Peng-Hui;Zhu, Hong-Ping;Luo, Hui;Weng, Shun
    • Smart Structures and Systems
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    • v.15 no.1
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    • pp.227-244
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    • 2015
  • This study develops a two stage procedure to identify the structural damage based on the optimized artificial neural networks. Initially, the modal strain energy index (MSEI) is established to extract the damaged elements and to reduce the computational time. Then the genetic algorithm (GA) and artificial neural networks (ANNs) are combined to detect the damage severity. The input of the network is modal strain energy index and the output is the flexural stiffness of the beam elements. The principal component analysis (PCA) is utilized to reduce the input variants of the neural network. By using the genetic algorithm to optimize the parameters, the ANNs can significantly improve the accuracy and convergence of the damage identification. The influence of noise on damage identification results is also studied. The simulation and experiment on beam structures shows that the adaptive parameter selection neural network can identify the damage location and severity of beam structures with high accuracy.

Densification of matrix graphite for spherical fuel elements used in molten salt reactor via addition of green pitch coke

  • He, Zhao;Zhao, Hongchao;Song, Jinliang;Guo, Xiaohui;Liu, Zhanjun;Zhong, Yajuan;Marrow, T. James
    • Nuclear Engineering and Technology
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    • v.54 no.4
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    • pp.1161-1166
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    • 2022
  • Green pitch coke with an average particle size of 2 mm was adopted as densifier and added to the raw materials of conventional A3-3 matrix graphite (MG) to prepare modified A3-3 matrix graphite (MMG) by the quasi-isostatic molding method. The structure, mechanical and thermal properties were assessed. Compared with MG, MMG had a more compact structure, and exhibited improved properties of higher mechanical strength, higher thermal conductivity and better molten salt barrier performance. Notably, under the same infiltration pressure of 5 atm, the fluoride salt occupation of MMG was only 0.26 wt%, whereas it was 15.82 wt% for MG. The densification effect of green pitch coke endowed MMG with improved properties for potential use in the spherical fuel elements of molten salt reactor.

Implementation of Melody Generation Model Through Weight Adaptation of Music Information Based on Music Transformer (Music Transformer 기반 음악 정보의 가중치 변형을 통한 멜로디 생성 모델 구현)

  • Seunga Cho;Jaeho Lee
    • IEMEK Journal of Embedded Systems and Applications
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    • v.18 no.5
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    • pp.217-223
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    • 2023
  • In this paper, we propose a new model for the conditional generation of music, considering key and rhythm, fundamental elements of music. MIDI sheet music is converted into a WAV format, which is then transformed into a Mel Spectrogram using the Short-Time Fourier Transform (STFT). Using this information, key and rhythm details are classified by passing through two Convolutional Neural Networks (CNNs), and this information is again fed into the Music Transformer. The key and rhythm details are combined by differentially multiplying the weights and the embedding vectors of the MIDI events. Several experiments are conducted, including a process for determining the optimal weights. This research represents a new effort to integrate essential elements into music generation and explains the detailed structure and operating principles of the model, verifying its effects and potentials through experiments. In this study, the accuracy for rhythm classification reached 94.7%, the accuracy for key classification reached 92.1%, and the Negative Likelihood based on the weights of the embedding vector resulted in 3.01.

A Comparative Analysis of the 7th and the Current Mathematics Textbooks and Workbooks on the Measurement Domain: Focused on the Degree of Guidance and Key Learning Elements (측정 영역에 관한 제7차와 현행 교과서 및 익힘책 비교 분석: 안내 정도와 측정의 주요 학습 요소를 중심으로)

  • Pang, JeongSuk;Kim, SuKyoung;Choi, InYoung
    • Journal of Elementary Mathematics Education in Korea
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    • v.16 no.2
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    • pp.227-252
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    • 2012
  • Given the lack of research on the measurement domain, this paper analyzed the statements related to length and area in the curricular materials developed under the 7th and the current mathematics curriculum in terms of the degree of guidance and the key learning elements of measurement. The results showed that despite the similarity of the most prevalent guidance type and learning elements, the current materials used open-ended or combined types in place of guided types and employed measurement reasoning and components while decreasing mere calculation in measurement, in comparison with the previous textbooks and workbooks. This paper close with implications on the revision of curricular materials related to the measurement domain as well as methodological suggestions of textbook analysis.

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