• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6673-6678
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• 2015

Recently, the free form buildings are constructed frequently. Exterior and interior components of these buildings have the free cross-section and a curved shape. So, There are many usages of classical finite element having tapered section and free-style shape. Some general commercial applications like ETABS, SAP2000, MIDAS are usually used for the safety evaluation of the free form structures. However, there are some limits in the accuracy of structural analysis and the length of analysis time because a very complicated finite element mesh have to be used. Therefore, In this study, a pre and post program module was developed to take advantage of general 3-D curved beam element which has a free-style curved shape and mathematical backgrounds. Pre-post processing module has been developed in this study was developed to control the curvature of the curved members by the NURBS control points. As a result, fast geometric modeling than was possible commercial applications. In addition, realistic depiction of the shape and behavior patterns were possible because of the free-form building allows visual check of the free form.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.4
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• pp.409-417
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• 2014

To prevent the occurrence of fractures in metal structures, it is very important to evaluate the 3D crack growth process in those structures and any related parts. In this study, tension tests and two simulations, namely, Simulation-I and Simulation-II, were performed using XFEM to evaluate crack growth in three dimensions. In the tension test, Mode I crack growth was observed for a notched metal specimen. In Simulation-I, a 3D reconstructed model of the specimen was created using CT images of the specimen. Using this model, an FE model was constructed, and crack growth was simulated using XFEM. In Simulation-II, an ideal notch FE model of the same geometric size as the actual specimen was created and then used for simulation. Obtained crack growth simulation results were then compared. Crack growth in the metal specimen was evaluated in three dimensions. It was shown that modeling the real shape of a structure with a crack may be essential for accurately evaluating 3D crack growth.

• Steel and Composite Structures
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• v.34 no.4
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• pp.511-524
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• 2020

In this research, a simple four-variable trigonometric integral shear deformation model is proposed for the static behavior of advanced functionally graded (AFG) ceramic-metal plates supported by a two-parameter elastic foundation and subjected to a nonlinear hygro-thermo-mechanical load. The elastic properties, including both the thermal expansion and moisture coefficients of the plate, are also supposed to be varied within thickness direction by following a power law distribution in terms of volume fractions of the components of the material. The interest of the current theory is seen in its kinematics that use only four independent unknowns, while first-order plate theory and other higher-order plate theories require at least five unknowns. The "in-plane displacement field" of the proposed theory utilizes cosine functions in terms of thickness coordinates to calculate out-of-plane shear deformations. The vertical displacement includes flexural and shear components. The elastic foundation is introduced in mathematical modeling as a two-parameter Winkler-Pasternak foundation. The virtual displacement principle is applied to obtain the basic equations and a Navier solution technique is used to determine an analytical solution. The numerical results predicted by the proposed formulation are compared with results already published in the literature to demonstrate the accuracy and efficiency of the proposed theory. The influences of "moisture concentration", temperature, stiffness of foundation, shear deformation, geometric ratios and volume fraction variation on the mechanical behavior of AFG plates are examined and discussed in detail.

• The Korean Journal of Petroleum Geology
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• v.1 no.1 s.1
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• pp.37-46
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• 1993

Two-dimensional gravity and magnetic models were constructed for seismic profiles in Block Ⅵ-2, offshore Korea. For each seismic profile, a longer length model showing geometric configurations of all employed polygonal bodies and an expanded version of the area of interests were made. The results of this modeling study indicate 1) that the depth to the deeper basement surface appear to be shallower than indicated in the seismic sections, 2) that the Middle Miocene section (the bottom formations in the models) appears to contain significant amounts of volcanic materials, 3) that identification and/or determination of depth to the top of basement is difficult in the study area due to thick volcanic materials in the lowermost formation (Middle Miocene), and 4) that the study area is unfavorable for hydrocarbon generation and accumulation due to wide spread volcanic activities during the Middle Miocene Epoch. The maximum calculated depth to the magnetic basement in the study area is approximately $4{\cal}km$ sub-sea.

• Molecules and Cells
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• v.23 no.2
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• pp.228-238
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• 2007

Since molecular structure of hnRNP is not available in foreseeable future, it is best to construct a working model for hnRNP structure. A geometric problem, assembly of $700{\pm}20$ nucleotides with 48 proteins, is visualized by a frame work in which all the proteins participate in primary binding, followed by secondary, tertiary and quaternary binding with neighboring proteins without additional import. Thus, 40S hnRNP contains crown-like secondary structure (48 stemloops) and appearance of 6 petal (octamers) rose-like architectures. The proteins are wrapped by RNA. Co-transcriptional folding for RNP fibril of FMR1 gene can produce 2,571 stem-loops with frequency of 1 stem-loop/15.3 nucleotides and 53 40S hnRNP beaded structure. By spliceosome driven reactions, there occurs removal of 16 separate lariated RNPs, joining 17 separate beaded exonic structures and anchoring EJC on each exon junction. Skipping exon 12 has 5'GU, 3'AG and very compact folding pattern with frequency of 1 stem-loop per 12 nucleotides in short exon length (63 nucleotides). 5' end of exon 12 contains SS (Splicing Silencer) element of UAGGU. In exons 10, 15 and 17 where both regular and alternative splice sites exist, SS (hnRNP A1 binding site) is observed at the regular splicing site. End products are mature FMR-1 mRNP, 4 species of Pri-microRNAs derived from introns 7,9,15 and 3'UTR of exon17, respectively. There may also be some other regulatory RNAs containing ALU/Line elements as well.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.3
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• pp.257-264
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• 2015

The structure of SpaceEye-1 developed by Satrec Initiative is designed to carry out various earth observation missions in harsh launch and orbit environments. This paper describes methodology of the structure design and analysis performed during the SpaceEye-1 development. The SpaceEye-1 structure is designed not only to endure the static/dynamic loads but also to protect a main payload and all other components under the launch environments. The structural design requirements were derived from the requirements of the launch vehicle, payload, and other subsystems from the initial development phase. Three-dimensional modeling process was used to verify geometric compatibility of the structure with the other subsystems, and finite element analysis was used to confirm whether the designed structure satisfied all the mechanical requirements derived from the launch vehicle and payload.

• Journal of Korea Technology Innovation Society
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• v.14 no.3
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• pp.578-598
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• 2011

This study estimates the value of photovoltaic core material technology, which is getting attention as a clean energy source. The estimation is based on the real option pricing model (ROPM). This study has two main contributions. The first is in the methodology. The process of modeling volatility, which is the most complicated stage in ROPM, is greatly simplified by using the stock price as a covariate representing the volatility of the real option's basic asset. The second contribution is the application of technology. In this study, the economic value of poly-silicon, a core material in the photovoltaic industry and recently surging in demand, is evaluated as a manufacturing technology. In a case study of a company in the photovoltaic industry, the stochastic process of a basic asset follows geometric Brownian motion (GBM), and the option value of firm A's poly-silicon manufacturing technology is estimated at 3.4 trillion won.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.5
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• pp.653-659
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• 2011

In general, electrocardiogram(ECG) signals are sampled with a frequency over 200Hz and stored for a long time. It is required to compress data efficiently for storing and transmitting them. In this paper, a method for compression of ECG data is proposed, using by Non Uniform B-spline approximation, which has been widely used to approximation theory of applied mathematics and geometric modeling. ECG signals are compressed and reconstructed using B-spline basis function which curve has local controllability and control a shape and curve in part. The proposed method selected additional knot with each step for minimizing reconstruction error and reduced time complexity. It is established that the proposed method using B-spline approximation has good compression ratio and reconstruct besides preserving all feature point of ECG signals, through the experimental results from MIT-BIH Arrhythmia database.

• Spatial Information Research
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• v.16 no.2
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• pp.249-261
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• 2008

This study proposes a method for acquiring and managing basic information on building, which is continuously updated through construction and re-construction, in order to implement 3D-GIS based on geometric shape information and building information. First of all, distinctions between BIM and GIS information models are described, and then an overview of CityGML for virtual city and its Level of Detail are introduced. At last, a prototype for extracting building geometry from BIM data in accordance with CityGML is presented for demonstration. By using IFC data from BIM, this approach enables a lot of firms and contractors in building industry to utilize their 2D/3D, data on sites and buildings, and also to save many effects for generating exterior and interior building models which are inevitable for implementing National GIS.

• Journal of the Korean Association of Geographic Information Studies
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• v.3 no.4
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• pp.1-10
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• 2000

Satellite remote sensing images have much more information compared to a paper map. But these images are generally handled as particular image format gained from optical sensor, and must be processed and analyzed by computer with high priced digital image processing system. For the extraction of digital elevation model(DEM) from satellite image, we used the overlay image by SPOT-3 of Chuncheon area at the Kangwon province. According to the image condition, the precious geometric correction, the bundle adjustment for ortho-image generation and the stereo image mapping by several technical approaches were processed. So that we developed the methods of automatic DEM extraction and efficient stereo image map generation which can improve the digital image processing steps. Also, we applied the multiple direction birdeye view image for modeling and analysis using the remotely sensed overlay images with high resolution.