• Title/Summary/Keyword: Heterogeneous Elements

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The study of drawing on the heterogeneous materials for the unidirectional alignment of carbon nanofiber in metal matrix nanocomposite (금속기지 나노복합재용 탄소나노섬유 일방향 배열을 위한 이종재 인발 연구)

  • 백영민;이상관;엄문광;김병민
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.10a
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    • pp.301-301
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    • 2003
  • In current study, Nanocomposites are reinforced with carbon nanofiber, carbon nanotube and SiC, etc. Since the nano reinforcements have the excellent mechanical, thermal and electrical properties compared with that of existing composites, it has lately attracted considerable attention in the various areas. Cu have been widely used as signal transmission materials for electrical electronic components owing to its high electrical conductivity. However, it's size have been limited to small ones due to its poor mechanical properties. Until now, strengthening of the copper alloy was obtained either by the solid solution and precipitation hardening by adding alloy elements or the work hardening by deformation process. Adding the alloy elements lead to reduction of electrical conductivity. In this aspect, if carbon nanofiber is used as reinforcement which have outstanding mechanical strength and electric conductivity, it is possible to develope Cu matrix nanocomposite having almost no loss of electric conductivity. It is expected to be innovative in electric conducting material market. The unidirectional alignment of carbon nanofiber is the most challenging task developing the cooer matrix composites of high strength and electric conductivity. In this study, the unidirectional alignment of carbon nanofibers which is used reinforced material are controlled by drawing process and align mechanism as well as optimized drawing process parameter are verified via numerical analysis. The materials used in this study were pure copper and the nanofibers of 150nm in diameter and of 10∼20$\mu\textrm{m}$ in length. The materials have been tested and the tensile strength was 75MPa with the elongation of 44% for the copper. it is assumed that carbon nanofiber behave like porous elasto-plastic materials. Compaction test was conducted to obtain constitutive properties of carbon nanofiber Optimal parameter for drawing process was obtained by analytical and numerical analysis considering the various drawing angles, reduction areas, friction coefficient, etc. The lower drawing angles and lower reduction areas provides the less rupture of co tube is noticed during the drawing process and the better alignment of carbon nanofiber is obtained.

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A Design of XML-Based Distributed MDR Retrieval System for Data Preparation (데이터준비를 위한 XML 기반의 분산 MDR 검색 시스템 설계)

  • Ko Sucbum;Youn Sungdae
    • Journal of Korea Multimedia Society
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    • v.7 no.9
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    • pp.1329-1338
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    • 2004
  • The purpose of data mining is to extract multi-dimensional information from a large database. The only information that we can extract from a large database is the column name, data type or simple comments included in the columns of database tables. With such unstructured and scarce information, it is very difficult and time taking to collect and to cleanse data by analyzing the purpose, characteristic and schema of the column during the data preparation step. In order to solve this problem, we propose solutions for reducing the time spent data preparation step in a relational database environment in this paper. That is, we propose useful elements to be considered during the data preparation step and then these elements are organized to constitute MDR(Metadata Registry) which is becoming the international standard of ISO/IEC : ll179. Finally, we propose a XML-based distributed MDR retrieval system that is convertible among heterogeneous systems and heterogeneous DBMSS.

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Construction of Framework for Metadata Integration Using Master Data Approach (마스터 데이터를 활용한 메타데이터 통합 프레임워크 구축)

  • Lee, Seungmin
    • Journal of Korean Library and Information Science Society
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    • v.44 no.1
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    • pp.201-225
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    • 2013
  • In order to overcome the problems of current approaches to metadata interoperability based on element mapping, this research proposed Master Element Framework that is an alternative approach to metadata interoperability. It is an approach to integrate metadata elements that have the same value, instead of direct mapping between similar elements. Master Element Framework is constructed to semantically integrate metadata elements in a hierarchical order and to interconnect between heterogeneous metadata standards. This approach is expected to be an alternative approach to metadata interoperability.

The Analysis on the Crossover Design in Current Fashion - Focusing on Comparing Advertisement - (현대패션에 나타난 크로스오버 디자인 분석 - 광고 이론의 적용을 중심으로 -)

  • Lim, Byung-Soo;Cho, Jean-Suk
    • Journal of the Korea Fashion and Costume Design Association
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    • v.15 no.2
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    • pp.135-150
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    • 2013
  • In the modern society, the crossover phenomenon has appeared increasing the value of creative brands as concepts contrary or heterogeneous are combined with each other by the flow of diversified societies and cultures. This research covers the use of crossover design in current fashion. To analyze the crossover design in current fashion, crossover design were collected and analyzed from a Collection TV program(Seoul: Dong Ah TV) and an Internet Web site(www.samsungdesign.net) from 2007 to 2010. The information obtained from the current fashion is compared with the advertisement area; by making this comparison we will make an analysis to determinate the crossover elements organized in 5 groups: extension and reduction, breakaway and destruction, fusion and combination, overlap and repetition, adjacent and similarity. This 5 crossover elements were analyzed in current fashion with the purpose of seeing how crossover elements are available in fashion field. Therefore, this study can offer invaluable suggestions for multifaceted research on how to come up with design concepts which apply crossover element to current fashion.

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Addressing the Challenges of Describing Alternative Format Materials: A Metadata Framework to Enhance Information Accessibility of People with Disabilities

  • Lee, Seungmin
    • Journal of Information Science Theory and Practice
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    • v.9 no.4
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    • pp.1-14
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    • 2021
  • Library communities face many problems and limitations in describing alternative format materials based on the traditional MAchine Readable Cataloging (MARC) structure. To address these problems, this research proposes an XML-based descriptive metadata framework that establishes general but fundamental bibliographic aspects of various alternative format materials by providing core elements that are essential in describing these materials. Different from existing bibliographic structures, the proposed metadata framework can represent a fundamental descriptive structure by establishing four upper-level categories, 17 core elements, and 10 sub-elements in a hierarchical structure optimized to alternative format materials. By using this principal descriptive structure, the proposed metadata framework can guide different institutions in the creation of bibliographic records for these materials in a consistent way. It is also expected to address the difficulties in describing alternative format materials in library communities and enhance the information accessibility of individuals with various types of disabilities. In addition, the proposed metadata framework is an alternative approach which functions as a mediator between heterogeneous characteristics of alternative format materials and the existing bibliographic structures in library communities.

Material distribution optimization of 2D heterogeneous cylinder under thermo-mechanical loading

  • Asgari, Masoud
    • Structural Engineering and Mechanics
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    • v.53 no.4
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    • pp.703-723
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    • 2015
  • In this paper optimization of volume fraction distribution in a thick hollow cylinder with finite length made of two-dimensional functionally graded material (2D-FGM) and subjected to steady state thermal and mechanical loadings is considered. The finite element method with graded material properties within each element (graded finite elements) is used to model the structure. Volume fractions of constituent materials on a finite number of design points are taken as design variables and the volume fractions at any arbitrary point in the cylinder are obtained via cubic spline interpolation functions. The objective function selected as having the normalized effective stress equal to one at all points that leads to a uniform stress distribution in the structure. Genetic Algorithm jointed with interior penalty-function method for implementing constraints is effectively employed to find the global solution of the optimization problem. Obtained results indicates that by using the uniform distribution of normalized effective stress as objective function, considerably more efficient usage of materials can be achieved compared with the power law volume fraction distribution. Also considering uniform distribution of safety factor as design criteria instead of minimizing peak effective stress affects remarkably the optimum volume fractions.

How to Integrate SMFD Display Software based on Heterogenous Graphic Design Tools (이종 그래픽 저작 도구 기반의 SMFD 화면 시현 소프트웨어 통합 방안)

  • Kyusik Kim;Yongjin Kwon;Seong Han Lee
    • Journal of Aerospace System Engineering
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    • v.18 no.2
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    • pp.79-86
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    • 2024
  • We have developed software for the SMFD that utilizes a range of graphic design tools. These tools enable us to effortlessly create graphic elements by defining their attributes, such as position and motion. Subsequently, we can convert these designs into source code and execute the resulting software on the target system, leveraging the graphic engines provided by the tools. However, when it comes to developing the displaying software for the SMFD using multiple graphic design tools on a single system, we face various challenges. In this paper, we will delve into these challenges and propose solutions for developing the displaying software for SMFD based on heterogeneous display design tools.

Physical and numerical modelling of the inherent variability of shear strength in soil mechanics

  • Chenari, Reza Jamshidi;Fatahi, Behzad;Ghoreishi, Malahat;Taleb, Ali
    • Geomechanics and Engineering
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    • v.17 no.1
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    • pp.31-45
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    • 2019
  • In this study the spatial variability of soils is substantiated physically and numerically by using random field theory. Heterogeneous samples are fabricated by combining nine homogeneous soil clusters that are assumed to be elements of an adopted random field. Homogeneous soils are prepared by mixing different percentages of kaolin and bentonite at water contents equivalent to their respective liquid limits. Comprehensive characteristic laboratory tests were carried out before embarking on direct shear experiments to deduce the basic correlations and properties of nine homogeneous soil clusters that serve to reconstitute the heterogeneous samples. The tests consist of Atterberg limits, and Oedometric and unconfined compression tests. The undrained shear strength of nine soil clusters were measured by the unconfined compression test data, and then correlations were made between the water content and the strength and stiffness of soil samples with different consistency limits. The direct shear strength of heterogeneous samples of different stochastic properties was then evaluated by physical and numerical modelling using FISH code programming in finite difference software of $FLAC^{3D}$. The results of the experimental and stochastic numerical analyses were then compared. The deviation of numerical simulations from direct shear load-displacement profiles taken from different sources were discussed, potential sources of error was introduced and elaborated. This study was primarily to explain the mathematical and physical procedures of sample preparation in stochastic soil mechanics. It can be extended to different problems and applications in geotechnical engineering discipline to take in to account the variability of strength and deformation parameters.

Chemical Properties of Indoor Individual Particles Collected at the Daily Behavior Spaces of a Factory Worker

  • Ma, Chang-Jin;Kang, Gong-Unn;Sakai, Takuro
    • Asian Journal of Atmospheric Environment
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    • v.11 no.2
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    • pp.122-130
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    • 2017
  • The main purpose of the study was to clarify the properties of individual particles collected at each behavior space of a factory worker. The samplings of size-segregated ($PM_{2.1-1.1}$ and $PM_{4.7-3.3}$) indoor particles were conducted at three different behavior spaces of a factory worker who is engaged in an auto parts manufacturing plant (i.e., his home, his work place in factory, and his favorite restaurant). Elemental specification (i.e., relative elemental content and distribution in and/or on individual particles) was performed by a micro-PIXE system. Every element detected from the coarse particulate matters of home was classified into three groups, i.e., a group of high net-counts (Na, Al, and Si), a group of intermediate net-counts (Mg, S, Cl, K, and Ca), and a group of minor trace elements (P, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, and Pb). The results of EF for $PM_{4.7-3.3}$ in home indicated that several heavy metals were generated from the sources within the house itself. An exceptional feature shown in the individual particles in workplace is that Cr, Mn, and Co were clearly detected in both fine and coarse particles. Cluster analysis suggested that the individual coarse particles ($PM_{4.7-3.3}$) collected at the indoor of factory were chemically heterogeneous and they modified with sea-salt, mineral, and artificially derived elements. The principal components in individual coarse particles collected at restaurant were sea-salt and mineral without mixing with harmful trace elements like chromium and manganese. Compared to the indoor fine particles of home and restaurant, many elements, especially, Cl, Na, Cr, Mn, Pb, and Zn showed overwhelmingly high net-counts in those of factory.

A Load Emulator for Low-power Embedded Systems and Its Application (저전력 내장형 시스템을 위한 부하의 전력 소모 에뮬레이션 시스템과 응용)

  • Kim, Kwan-Ho;Chang, Nae-Hyuck
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.42 no.6
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    • pp.37-48
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    • 2005
  • The efficiency of power supply circuits such as DC-DC converters and batteries varies on the trend of the power consumption because their efficiencies are not fixed. To analyze the efficiency of power supply circuits, we need the temporal behavior of the power consumption of the loads, which is dependent on the activity factors of the devices during the operation. Since it is not easy to model every detail of those factors, one of the most accurate power consumption analyses of power supply circuits is measurement of a real system, which is expensive and time consuming. In this paper, we introduce an active load emulator for embedded systems which is capable of power measurement, logging, replaying and synthesis. We adopt a pattern recognition technique for data compression in that long-term behaviors of power consumption consist of numbers of repetitions of short-term behaviors, and the number of short-term behaviors is generally limited to a small number. We also devise a heterogeneous structure of active load elements so that low-speed, high-current active load elements and high-speed, low-current active load elements may emulate large amount and fast changing power consumption of digital systems. For the performance evaluation of our load emulator, we demonstrate power measurement and emulation of a hard drive. As an application of our load emulator, it is used for the analysis of a DC-DC converter efficiency and for the verification of a low-power frequency scaling policy for a real-time task.