• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.702-707
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• 2004

This article is concerned with container pose estimation using CCD a camera and a range sensor. In particular, the issues of characteristic point extraction and image noise reduction are described. The Euler-Lagrange equation for gaussian and random noise reduction is introduced. The alternating direction implicit(ADI) method for solving Euler-Lagrange equation based on partial differential equation(PDE) is applied. The vertex points as characteristic points of a container and a spreader are founded using k order curvature calculation algorithm since the golden and the bisection section algorithm can't solve the local minimum and maximum problems. The proposed algorithm in image preprocess is effective in image denoise. Furthermore, this proposed system using a camera and a range sensor is very low price since the previous system can be used without reconstruction.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.5
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• pp.365-371
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• 2015

Hull plate consists of various types of curved plates and there also exists corresponding processing methods. Typically, curved plates can be divided into convex type and saddle type. Large amount of research has been conducted mainly focusing on application of processing method of convex type, saddle type and hybrid type, but research on determination and processing method application of the most difficult S-shaped curved plate that has inflection lines has not been carried out yet. In this paper, as the fundamental research of appropriate processing method application, a calculation method is proposed to calculate inflection lines on curved plates. In order to calculate inflection lines, normal curvature and information of fabricated curved plates should be utilized. We compare the workability of the fabrication for hull plate using inflection line.

• International Journal of CAD/CAM
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• v.3 no.1_2
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• pp.31-40
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• 2003

In this paper, first order slice height calculation in Laminated Object Manufacturing (LOM) of free form surfaces is done with two different considerations: that a) the cutter trajectory is oriented in the direction of local absolute maximum more in number when compared to the case where the cutter trajectory is contained in the normal vertical section (NVS). However, it would help in achieving higher form accuracy of the final part because it would be a form of worst-case check. For the second proposed strategy, least number of slices results, thereby reducing overall build time drastically.

• Korea-Australia Rheology Journal
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• v.14 no.3
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• pp.107-114
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• 2002

Residual stress distribution in injection molded short fiber composites is determined by using the layer-removal method. Polystyrene is mixed with carbon fibers of 3% volume fraction (4.5% weight fraction) in an extruder and the tensile specimen is injection-molded. The layer-removal process, in which removing successive thin uniform layers of the material from the surface of the specimen by a milling machine, is employed and the resulting curvature is acquired by means of an image processing. The isotropic elastic analysis proposed by Treuting and Read which assumes a constant Yaung’s modulus in the thickness direction is one of the most frequently used methods to determine residual stresses. However, injection molded short fiber composites experience complex fiber orientation during molding and variation of Yaung’s modulus distribution occurs in the specimen. In this study, variation of Yaung’s modulus with respect to the thickness direction is considered for calculation of the residual stresses as proposed by White and the result is compared with that by assuming constant modulus. Residual stress distribution obtained from this study shows a typical stress profile of injection-molded products as reported in many literatures. Young’s modulus distribution is predicted by using numerical methods instead of experimental results. For the numerical analysis of injection molding process, a hybrid FEM/FDM method is used in order to predict velocity, temperature field, fiber orientation, and resulting mechanical properties of the specimen at the end of molding.

• Structural Engineering and Mechanics
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• v.68 no.6
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• pp.721-733
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• 2018

The modal frequency responses of functionally graded (FG) sandwich doubly curved shell panels are investigated using a higher-order finite element formulation. The system of equations of the panel structure derived using Hamilton's principle for the evaluation of natural frequencies. The present shell panel model is discretised using the isoparametric Lagrangian element (nine nodes and nine degrees of freedom per node). An in-house MATLAB code is prepared using higher-order kinematics in association with the finite element scheme for the calculation of modal values. The stability of the opted numerical vibration frequency solutions for the various shell geometries i.e., single and doubly curved FG sandwich structure are proven via the convergence test. Further, close conformance of the finite element frequency solutions for the FG sandwich structures is found when compared with the published theoretical predictions (numerical, analytical and 3D elasticity solutions). Subsequently, appropriate numerical examples are solved pertaining to various design factors (curvature ratio, core-face thickness ratio, aspect ratio, support conditions, power-law index and sandwich symmetry type) those have the significant influence on the free vibration modal data of the FG sandwich curved structure.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.5
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• pp.723-729
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• 2013

This paper presents an parallel type Linear Induction Motor with ununiform airgap for a shallow-depth underground train with 100‰ grade and 15 m curvature. This parallel type LIM has enough gradability but has inherently ununiform airgap between center and end parts. Consequently, performance when the train passes curved section should be considered with transient analysis. Moreover, general parallel operation, 1C2M which is usually used for train operation, deteriorates LIM performance because of different line velocity between inner and outer LIMs. Transient analysis has many problems such as huge model, lots of meshes, very long calculation time, truncation error and so on. This paper has presented a novel technique using equivalent linear rotating model in order to solve these problems and has analyzed parallel type LIM by using the proposed technique. Finally, LIM performance according to independent operating control has been investigated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.4
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• pp.515-523
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• 2012

In this paper, the resonance characteristics and radiation characteristics of a spherical patch on a dielectric sphere are analyzed. Resonance characteristics can be obtained from the resonant frequency and the quality factor. Radiation characteristics can be also analyzed from the E-field in the far region. In order to calculate these parameters, spectral domain analysis method is applied. Algebraic equation can be obtained in spectral domain through Vector Legendre transform pair and Galerkin's method. So, efficient calculation is possible numerically. It is investigated that radius, curvature of a spherical patch, and dielectric constant of a dielectric sphere have an effect on characteristics of a spherical patch.

• Korean Journal of Optics and Photonics
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• v.21 no.6
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• pp.247-253
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• 2010

A dual-layer light guide plate (DLGP) was designed and a simulation was done to optimize the structure of the light guide plates used at backlight units while maintaining the luminance, uniformity and viewing angle by reducing the optical sheet. The characteristic of DLGP with prism pattern with curvature on the top surface is simulated and the luminance and uniformity are obtained. In order to improve the uniformity, the V groove prism pattern on the bottom surface was turned by an angle of $90^{\circ}$. In particular, we used the pitch calculation program to select the value of the ratio (Max : Min) between the pitch at the extreme outside and the pitch at the middle, the number of V groove lines and the variance at the bottom pattern of DLGP. After that, the optimum distance between V grooves was determined. For optimizing the DLGP, we examined the uniformity again by changing the number of pattern grooves on the bottom surface of DLGP. As a result of the simulation, we find that the BLU with DLGP has a uniformity of 90.6% and viewing angle $145^{\circ}$.