• Journal of the Korean Society for Precision Engineering
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• v.25 no.4
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• pp.77-85
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• 2008

PDF is widely accepted as a standard document format and now it supports 3D contents as well. Within the engineering application areas, this new 3D feature may be used to support sharing of 3D documents and thus collaboration between engineering departments, suppliers and partners. In this paper, we describe a system that automatically generates formatted engineering documents including 3D data converted from 3D applications such as commercial 3D CAD viewer. The system consists of two major modules. One is U3D conversion module and the other is PDF conversion module. U3D conversion module extracts geometry, view data, assembly and disassembly information from 3D viewer and converts to U3D format, currently in IDTF text file format. PDF conversion module generates a PDF file and inserts U3D data, various annotation information, and scripts for custom generated operations such as assembly and disassembly in the PDF document.

• Journal of the Korea Convergence Society
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• v.4 no.3
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• pp.27-33
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• 2013

Conventional bar code has the appearance of line bars and spaces, called as one-dimensional bar code. In contrast, the information in two-dimensional bar code is represented by either a small, rectangular or square with the types of mosaic and Braille. The two-dimensional bar code is much more efficient than one-dimensional bar code because it can allow to store and express large amounts of data in a small space and so far there is also a little information about decoding the Data Matrix in base 256 mode. According to the ISO international standards, there are four kinds of bar code: QR code, Data Matrix, PDF417, and Maxi code. In this paper, among them, we focus on describing the basic concepts of Data Matrix in base 256 mode, how to encode and decode them, and how to organize them in detail. In addition, Data Matrix can be organized efficiently depending on the modes of numeric, alphanumeric characters, and binary system and expecially, we focus on describing how to decode the Data Matrix code by four modes.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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• pp.50-55
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• 2001

To simulate the combustion process under stratified charged conditions, like GDI engines, the new combustion model is proposed, which is based on Welter's FAE model and Peters' PDF model for considering primary reactions. In addition to these models, the new laminar burning velocity correlation and diffusion flame model are also included in the proposed model. The former can be applicable to much wider range of equivalence ratio, pressure and temperature than the others, such as Keck's and Guilder's models, and the latter has been derived from water-gas shift reaction and hydrogen oxidation, by which the secondary reactions can be considered after primary reactions. 3-D computation has been performed by using STAR-CD v3.05 in the simple cylindrical geometry under stratified charged condition. Judging from the calculated results, the present model proves to be reasonable to simulate the characteristics of flame propagation and concentrations of products in burned regions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.975-977
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• 2013

Arduino is for design based on open source prototyping platform, artist, designer, hobby activists, etc, i has been designed for all those who are interested in the environment construct. Arduino adventage you can easily create applications hardware, without deep knowledge about the hardware. Configuration of arduino using AVR microcontroller ATmage 168, software to action arduino using arduino program, MATLAB, Processing. Arduino is open source base, you can hardware production directly and using shield additionally, the arduino can be combined. Processing iis open source. You can 2D, 3D, PDF output, using P3D and OpenGL graphics. Also you can check by running a stand-alone application. Through a combination of Arduino, library support, such as sound, video, and computer vision can be expanded, this program is the Android phone and iPhone programming. In this paper, sortware was used for Processing, hardware was used for arduino MegaADK board, After making easy 2axis game, using the software and hardware verification.

• Journal of Practical Engineering Education
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• v.14 no.1
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• pp.91-97
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• 2022

Recently, as per a representative education method to develop core capabilities (such as critical thinking, communication, collaboration, and creativity) problem based learning (PBL) has been widely adopted in universities. Two important features of PBL are 'collaboration between team members' and 'participation based self-directed learning'. These two features should be satisfied in online education, although it is difficult due to the limitation on space and time in the COVID-19 pandemic. This paper presents a new design of PBL class in Metaverse, based on improving the online PBL class operated in the previous semesters in the H university. In the proposed PBL class, students are able to display materials (e.g., image, pdf, video files) in 3D virtual space, that are related to problem solving. The 3D virtual space is called gallery in this paper. The concept of gallery allows for active participation of students. In addition, the gallery can be used as a tool for collaborative meeting or for final presentation. If possible, the new design of PBL class will be applied and its effectiveness will be analyzed.

• 한국전산유체공학회:학술대회논문집
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• 1999.05a
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• pp.199-204
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• 1999

Three dimensional numerical analysis for the turbulent reactive flow and radiative heat transfer in the walking beam type of a reheat furnace in POSCO has been carried out by the industrial code FLUENT. Computations an based on the conservation equations of mass, momentum, energy and species with the $k-{\varepsilon}$ turbulence model and mixture fraction/PDF(Probability Density Function) approach for the combustion rate. Radiative heat transfer is computed by the discrete ordinates radiation model in combination with the weighted-sum-of-gray-gas model for the absorption coefficient of gas medium. The predicted temperture distribution in the reheat furnace and energy flow fractions are in reasonable agreement with the measurement data.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.3 s.234
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• pp.314-321
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• 2005

Discrete Wavelet Transform (DWT) has been applied to the Direct Numerical Simulation (DNS) data of turbulent channel flow. DWT splits the turbulent flow into two orthogonal parts, one corresponding to coherent structures and the other to incoherent background flow. The coherent structure is extracted from not vorticity field but velocity's since the channel flow is not isoropic. By comparing DWT's result of channel flow with that of isotropic flow, it is shown that coherent structure maintains the properties of original channel flow. The velocity field of coherent structures can be represented by few wavelet modes and that these modes are sufficient to reproduce the velocity probability density function (PDF) and the energy spectrum over the entire inertial range. The remaining incoherent background flow is homogeneous, has small amplitude, and is uncorrelated. These results are compared with those obtained for the same compression rate using large eddy simulation (LES) filtering. In contrast to the incoherent background flow of DWT, the LES subgrid scales have a much larger amplitude and are correlated, which makes their statistical modeling more difficult.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.247-251
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• 2010

It is very difficult to understand and estimate the heat transfer and flow characteristics in the combustor, which is one of main components in the Auxiliary Power Unit (APU), because its flow filed has very complex structure. In this paper, specified is characteristics of injection and flow through different air goles in the liner, which consist of large circular holes film cooling holes, and tangential air swirl holes. The durability of the liner depends on whether the surface of the liner is exposed to the hot gas over 1000 $^{\circ}C$ of a temperature or net. It is proved that the locations of hot spots estimated from the calculation using CFD are matched well with that from the test. In this study, CFD simulations were performed to examine the heat transfer and temperature distributions in and about a liner wall with film cooling on the wall. This computational study is based on the ensemble average continuity, compressible Navier-Stokes, energy, and PDF combustion equations closed by the standard $k-{\varepsilon}$ turbulence model with standard wall functions for the gas phase and the Fourier equations for conduction in the solid phase.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1813-1818
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• 2004

Discrete Wavelet Transform (DWT) has been applied to the Direct Numerical Simulation (DNS) data of turbulent channel flow. DWT splits the turbulent flow into two orthogonal parts, one corresponding to coherent structures and the other to incoherent background flow. The coherent structure is extracted from not vorticity field but velocity's since the channel flow is not isotropic. By comparing DWT's result of channel flow with that of isotropic flow, it is shown that coherent structure maintains the properties of original channel flow. The velocity field of coherent structures can be represented by few wavelet modes and that these modes are sufficient to reproduce the velocity probability distribution function (PDF) and the energy spectrum over the entire inertial range. The remaining incoherent background flow is homogeneous, has small amplitude, and is uncorrelated. These results are compared with those obtained for the same compression rate using large eddy simulation (LES) filtering. In contrast to the incoherent background flow of DWT, the LES subgrid scales have a much larger amplitude and are correlated, which makes their statistical modeling more difficult.

• Communications of Mathematical Education
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• v.31 no.3
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• pp.241-255
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• 2017

The 4th industrial revolution is coming. In order to prepare for the new learning environment with it, we may need digital mathematics textbooks that fully utilize all possible technologies. So various attempts have been made in elementary and middle school mathematics education. However, despite the importance of higher mathematics, we haven't seen a best possible math digital textbooks yet in Korea. In this paper, we introduce our new model of interactive math digital textbook about Linear Algebra/ Calculus/ Differential Equations/ Statistics/ Engineering Math. Especially, this manuscript focuses on our experience of using digital contents and interactive labs for developing a new model for linear algebra digital textbook. We introduce our works on linear algebra digital textbooks which include pdf e-book, web contents, video clips of lectures, interactive lab. Using this linear algebra digital textbook, students can freely use any mobile devices to access diverse learning materials, lessons, and hands-on exercises without any limitations. Also, times saved in the computation, coding, and typing process can be used to have more discussions for deeper understanding of mathematical concepts. This type of linear algebra digital textbook, which contains all interactive free cyber-lab with codes and all lectures for each sections, can be considered as a new model for the next generation of math digital textbook.