• Structural Engineering and Mechanics
• /
• v.57 no.2
• /
• pp.327-355
• /
• 2016

A new analytical derivation of the elastodynamic point load solutions for an isotropic multi-layered half-space is presented by means of the precise integration method (PIM) and the approach of dual vector. The time-harmonic external load is prescribed either on the external boundary or in the interior of the solid medium. Starting with the axisymmetric governing motion equations in a cylindrical coordinate system, a second order ordinary differential matrix equation can be gained by making use of the Hankel integral transform. Employing the technique of dual vector, the second order ordinary differential matrix equation can be simplified into a first-order one. The approach of PIM is implemented to obtain the solutions of the ordinary differential matrix equation in the Hankel integral transform domain. The PIM is a highly accurate algorithm to solve sets of first-order ordinary differential equations and any desired accuracy of the dynamic point load solutions can be achieved. The numerical simulation is based on algebraic matrix operation. As a result, the computational effort is reduced to a great extent and the computation is unconditionally stable. Selected numerical trials are given to validate the accuracy and applicability of the proposed approach. More examples are discussed to portray the dependence of the load-displacement response on the isotropic parameters of the multi-layered media, the depth of external load and the frequency of excitation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.05a
• /
• pp.210-213
• /
• 2010

Recent experimental data shows that the noticeable feature of irregular roughened spots on the fuel surface occurs during the combustion test. The generation of these unexpected patterns is likely to be resulted from the disturbed boundary layer due caused by wall blowing which is intended to simulate the process of fuel vaporization. LES without chemical reaction was conducted to investigate the flow characteristics at the near-fuel surface and the behavior of turbulent structures which is evolved by the wall blowing at the Reynolds number of 23,000. Cylindrical geometry was considered to get the most reality of the calculation results because real hybrid rocket motor is circular grain configuration. It was shown that the wall blowing pushed turbulent structures upwards making them tilted and this skewed displacement, in effect, left the foot prints of the structures on the surface. This change of kinematics may explain the formation of irregular isolated spots on the fuel surface observed in the experiment.

• Journal of the Korean Ceramic Society
• /
• v.52 no.5
• /
• pp.299-303
• /
• 2015

The electrolyte is an important component in determining the performance of Fuel Cells. Especially, investigation of the conduction properties of electrolytes plays a key role in determining the performance of the electrolyte. The electrochemical properties of Yttrium stabilized zirconia (YSZ) were measured to allow the use of this material as an electrolyte for solid oxide fuel cells (SOFC) in the temperature range of $700-1000^{\circ}C$ and in $0.21{\leq}pO_2/atm{\leq}10^{-23}$. A Hebb-Wagner polarization experimental cell was optimally manufactured; here we discuss typical problems associated with making cells. The partial conductivities due to electrons and holes for 8YSZ, which is known as a superior oxygen conductor, were obtained using I-V characteristics based on the Hebb-Wagner polarization method. Activation energies for holes and electrons are $3.99{\pm}0.17eV$ and $1.70{\pm}0.06eV$ respectively. Further, we calculated the oxygen ion conductivity with electron, hole, and total conductivity, which was obtained by DC four probe conductivity measurements. The oxygen ion conductivity was dependent on the temperature; the activation energy was $0.80{\pm}0.10eV$. The electrolyte domain was determined from the top limit, bottom limit, and boundary (p=n) of the oxygen partial pressure. As a result, the electrolyte domain was widely presented in an extensive range of oxygen partial pressures and temperatures.

• Archives of design research
• /
• v.15 no.3
• /
• pp.201-212
• /
• 2002

This thesis is to study about The Issue of Treating Information, according to the circumstance of Digital Media in Contemporary Design. The Digital Design is being able to be organized by developed Science and Technology. Ultra fashionable mode of digital design is leading human life more comfortable and serviceable: and proceeded by technology aheaded by science Developed Computer will help the Space science and virtual reality. and They will lead more developed industrial culture. The design is influencing international society and economic circumstance, and it's making the changedness of product and commercial route. virtual reality and simulation made by developed science is resulting in new design revolution in our society. Especially, it is able to make more bigger result in image breaking and reassimilation. The technology of developed information treating infra is able to transmit & receive a message, which are beyond our sensual boundary and is the meaning of the human-being's progressive development of science culture. Developed information treating methodology made by technology and science of restoration will be Neo-reality for artists and are the cause of great changedness in 21st century's art & design.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.5
• /
• pp.1025-1034
• /
• 2009

In steel making production line, steel slabs are given a unique identification number. This identification number, Slab management number(SMN), gives information about the use of the slab. Identification of SMN has been done by humans for several years, but this is expensive and not accurate and it has been a heavy burden on the workers. Consequently, to improve efficiency, automatic recognition system is desirable. Generally, a recognition system consists of text localization, text extraction, character segmentation, and character recognition. For exact SMN identification, all the stage of the recognition system must be successful. In particular, the text localization is great important stage and difficult to process. However, because of many text-like patterns in a complex background and high fuzziness between the slab and background, directly extracting text region is difficult to process. If the slab region including SMN can be detected precisely, text localization algorithm will be able to be developed on the more simple method and the processing time of the overall recognition system will be reduced. This paper describes about the slab region localization using SIFT(Scale Invariant Feature Transform) features in the image. First, SIFT algorithm is applied the captured background and slab image, then features of two images are matched by Nearest Neighbor(NN) algorithm. However, correct matching rate can be low when two images are matched. Thus, to remove incorrect match between the features of two images, geometric locations of the matched two feature points are used. Finally, search rectangle method is performed in correct matching features, and then the top boundary and side boundaries of the slab region are determined. For this processes, we can reduce search region for extraction of SMN from the slab image. Most cases, to extract text region, search region is heuristically fixed [1][2]. However, the proposed algorithm is more analytic than other algorithms, because the search region is not fixed and the slab region is searched in the whole image. Experimental results show that the proposed algorithm has a good performance.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.22 no.10
• /
• pp.1327-1333
• /
• 2018

Numerical analysis has the advantage that no actual flow pathways need to be formulated, making this technique especially useful for simulation analysis such as pathway design. However, it does require that the complete physical parameters of the fluid and the complete boundary conditions be known. If any of them are unknown, either the calculation will become impossible, or even if the calculation does converge, the reliability of the result will be low. Therefore, a means of more accurate acquisition of flow information is required. In this paper, we present techniques for estimating flow field from a constraint equation for image information and velocity field, based on the image intensity changes accompanying the motion of dye in waterway. In the equation, we entered a stabilizing term to suppress estimation error. We show the effectiveness of our method through experiments with generated and real images of a Karman vortex.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.10
• /
• pp.2073-2081
• /
• 2002

In product design and manufacturing, axiomatic design provides a systematic approach for the decision-making process. Two axioms have been defined such as the Independence Axiom and the Information Axiom. The Information Axiom states that the best design among those that satisfy the independence axiom is the one with the least information content. In other words, the best design is the one that has the highest probability of success. On the other hand, the Taguchi robust design is used in the two-step process; one is "reduce variability," and the other is "adjust the mean on the target." The two-step can be interpreted as a problem that has two FRs (functional requirements). Therefore, the Taguchi method should be used based on the satisfaction of the Independence Axiom. Common aspects exist between the Taguchi method and Axiomatic Design in that a robust design is induced. However, different characteristics are found as well. The Taguchi method does not have the design range, and the probability of success may not be enough to express robustness. Our purpose is to find the one that has the highest probability of success and the smallest variation. A new index is proposed to satisfy these conditions. The index is defined by multiplication of the robustness weight function and the probability density function. The robustness weight function has the maximum at the target value and zero at the boundary of the design range. The validity of the index is proved through various examples.gh various examples.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.26 no.2
• /
• pp.227-237
• /
• 2002

A numerical technique for simulating the aggregation of charged particles was presented with a Brownian dynamic simulation in the free molecular regime. The Langevin equation was used for tracking each particle making up an aggregate. A periodic boundary condition was used for calculation of the aggregation process in each cell with 500 primary particles of 16 nm in diameter. We considered the thermal force and the electrostatic force for the calculation of the particle motion. The electrostatic force on a particle in the simulation cell was considered as a sum of electrostatic forces from other particles in the original cell and its replicate cells. We assumed that the electric charges accumulated on an aggregate were located on its center of mass, and aggregates were only charged with pre-charged primary particles. The morphological shape of aggregates was described in terms of the fractal dimension. In the simulation, the fractal dimension for the uncharged aggregate was D$\_$f/ = 1.761. The fractal dimension changed slightly for the various amounts of bipolar charge. However, in case of unipolar charge, the fractal dimension decreased from 1.641 to 1.537 with the increase of the average number of charges on the particles from 0.2 to 0.3 in initial states. In the bipolar charge state, the average sizes of aggregates were larger than that of the uncharged state in the early and middle stages of aggregation process, but were almost the same as the case of the uncharged state in the final stage. On the other hand, in the unipolar charge state, the average size of aggregates and the dispersion of particle volume decreased with the increasing of the charge quantities.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.20 no.3
• /
• pp.293-301
• /
• 2002

MGF(Marine Geographical Framework) data are the essential data sets concerning graphical and attribute information on coast and ocean among various marine-related data, which consist of framework data of the National Spatial Data Infrastructure(NSDI). This study did research and analyzed the development of current data, the situation of its usage, related technical environment and case study of foreign countries through the survey on the users and experts. Then the item of marine geographical framework data was selected in accordance with the measures for usage and management of possible MGF data. A map was pilot producted based on selected items and MGF data was presented through making up some problems shown ill the process. The importance of GIS will be growing continuously which can develop, deal with and provide the various data to efficiently manage coast and ocean. Accordingly, the MGF data will be applied to various areas such as Internet or raw data for marine information system.

• Journal of the Korea Convergence Society
• /
• v.10 no.11
• /
• pp.23-31
• /
• 2019

With the advent of the era of mass tourism in China and people's yearning for a better life, the demand for family tourism is increasing. This paper adds the filial piety concept variable to the original model based on the theory of planned behavior (TPB). It tests the influence mechanism of attitude, subjective norm, perceived behavior control and filial piety on the intention of family tourism behavior. The results show that； Attitude and subjective norms have significant influence on the intention of family tourism behavior; Perceptual behavior control has no significant influence on the intention of family tourism behavior; Mutual filial piety has a significant impact on family tourism behavior and authoritative filial piety has no significant effect on family tourism decision-making behavior. This conclusion expands the application boundary of the theory of planned behavior in the study of family tourism behavior intentions, and provides application reference for tourists and tourism enterprises.