• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.7
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• pp.107-116
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• 2014

This paper presents camera-based road surface marking detection methods suited to sensor fusion-based positioning system that consists of low-cost GPS (Global Positioning System), INS (Inertial Navigation System), EDM (Extended Digital Map), and vision system. The proposed vision system consists of two parts: lane marking detection and RSM (Road Surface Marking) detection. The lane marking detection provides ROIs (Region of Interest) that are highly likely to contain RSM. The RSM detection generates candidates in the regions and classifies their types. The proposed system focuses on detecting RSM without false detections and performing real time operation. In order to ensure real time operation, the gating varies for lane marking detection and changes detection methods according to the FSM (Finite State Machine) about the driving situation. Also, a single template matching is used to extract features for both lane marking detection and RSM detection, and it is efficiently implemented by horizontal integral image. Further, multiple step verification is performed to minimize false detections.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.12 s.103
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• pp.1246-1254
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• 2005

Theoretical investigation is made on the electromagnetic fields generated by an impulsive point current source, fur the VV, HV, and VH problems at the interface between an isotropic upper half-space medium and a normally uniaxial lower half-space medium. The electric fields of these problems are associated only with the extraordinary-wave components in the Fourier-Laplace domain. Applying the Cagniard-de Hoop method to each problem, the time-domain solutions of the wave fields are obtained. The fields of the VV case can be expressed in explicit(integral-free) forms. The fields of the HV and VH cases are not integral-free, but the major singularities implicit in the integral solutions can be analytically extracted. The interfacial far fields in the frequency domain are determined by the singularities in the time domain.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.2
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• pp.250-258
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• 2010

A numerical analysis of reactive flow in a liftoff flame is accomplished to elucidate the characteristics of flame propagation velocity and volume integral of reaction rate with the variation of nozzle diameter and fuel injection flow rate in a liftoff flame consisted with fuel rich region, fuel lean region and diffusion flame region. The increase of fuel injection velocity enhances flame propagation velocity for the selected three nozzle diameter(d=0.25, 0.30, 0.35mm), but its effect on the flame propagation velocity is not much greater than 4.3%. The increase of fuel flow rate is directly and linearly related with the volume reaction rate and so the volume reaction rate, not the flame propagation velocity, might be considered to accommodate the variation of fuel flow rate in a liftoff flame.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.416-422
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• 2017

The robot control with safety consideration is required since robots and human work together in the same space more frequently in these days. For safety, robots must have compliance to human force and robust tracking performance with high impednace for the nonhuman disturbances. The novel idea is proposed to achieve the compliance and high impedance with one controller structure. For the compliance, the ISMC(Integral Sliding Mode Control) and HDOB(Human Disturbance Observer) The human force is identified by using the human band pass filter and its output is sent to the sliding surface. The sliding mode dynamic is affected by human disturbance and the compliance for human is achieved. The disturbances besides human frequencies are decoupled by the ISMC and the robust tracking is achieved. The additional LDOB(Low Frequency Disturbance Observer) decreases the maxim nonlinear gain and leads low chattering. The introduction of human disturbance into the sliding mode dynamic is the main novel idea of this paper.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.1
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• pp.11-22
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• 2019

In this paper, a Rankine source method is applied and validated to analyze the hydrodynamic response of a three-dimensional floating structure in the frequency domain. The boundary value problems for radiation and diffraction problem are solved by using a desingularized indirect boundary integral equation method (DIBIEM). The DIBIEM is simpler and faster than conventional methods based on the numerical surface integration of Green's function because the singularities of Green's function are located outside of fluid regions. In case of floating structure with complex geometry, it is difficult to desingularize the singularities of Green's function consistently. Therefore a mixed approach is carried out in this study. The mixed approach is partially desingularized except singularities of the body. Wave drift loads are calculated by the middle-field formulation method that is mathematically simple and has fast convergence. In order to validate the accuracy of the developed program, various numerical simulations are carried out and these results are analyzed and compared with previously published calculations and experiments.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.1
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• pp.18-24
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• 2017

This paper is a part of developing a computer code that can be used to generate synthetic IR images by calculating the outgoing infrared signal from objects. To predict the reflected component that is a part of the outgoing IR signal, such as those components reflected from the target surface by the solar and sky irradiations, it is necessary to calculate the complicated BRDF values for considering the directional surface reflection characteristics. Since the calculation of reflectance using the BRDF requires a large amount of computation time due to the hemispherical integral term, it is frequently restricted in applying for a real-time prediction of IR signal. In this research, the simplified method for calculating IR reflected component has been proposed by replacing the integral terms into two parts, a directionally uniform component and a step function representing the specular component, to reduce computation time. The proposed method is proved to result in very fast calculation of the BRDF (up to 600 times faster calculations) for most of the surfaces with minimal loss of the accuracy.

• Computational Structural Engineering
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• v.9 no.4
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• pp.189-198
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• 1996

The fracture behaviour of concrete gravity dam mainly due to uplift pressure acting at the crack face was studied. Triangular type and parabolic type distribution of the uplift pressure including uniform type were first considered in case of calculating stress intensity factor(SIF) by the surface integral method. Second, the directions of crack propagation according to the uplift pressure distribution were pursued by FRANC(FRacture ANalysis Code). Third, critical crack lengths according to the uplift pressure distribution under the overflow depth were calculated. The SIF values obtained from the surface integral method were compared with those by FRANC and relatively good agrements could be obtained between both of them. And it could be seen that the direction of crack propagation in case of triangular pressure distribution was a little benter to the dam base than the one by the uniform type. Maximum critical crack lengths under the overflow depth were obtained at about 2/5-1/2 of the dam height.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.5
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• pp.445-454
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• 2015

In this paper, we propose an optimal design method for a dual reflector antenna(DRA) using the Genetic algorithm. In order to reduce the computational burden during the optimal design, we exploit the iterative physical optics(IPO) to calculate the surface current distribution at each reflector antenna. To improve the accuracy, we consider the shadow effect by the structure and the coupling effect by the multi-reflection based on the iterative MFIE(Magnetic Field Integral Equation). To reduce the number of design variables and generate a smooth surface, we use the Bezier function with the control points, which become the design variables in this paper. We adopt the HPBW(Half Power Beam Width), the FNBW(First Null Beam Width), and the SLL(Side Lobe Level) as the objective or cost functions. To verify the results, we compare them with the those of the commercial tool.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.677-680
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• 2008

The paper deals with the analysis of radiation characteristics of antenna in the multi-layered media structures. The dyadic Green's function for three layer medium is complex because the Green's functions belonging to the kernel of the integral equation are expressed as Sommerfeld integrals, in which surface wave effects are automatically included. When certain condition are met, the integral can be evaluated approximated by the method of Saddle-point integration. In this study, we propose a method to calculate a radiation pattern for several antennas by using the method of Saddle-point integration. Numerical results show how the radiation characteristics are affected by parameter of dielectric media.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.8
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• pp.765-774
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• 2004

In this paper, a novel approximate solution for scattering by a very thin planar homogeneous dielectric scatterer with an arbitrary shape is formulated. This solution is based on a volumetric integral equation and is expressed in terms of Fourier transform. It is shown that the obtained solution is reduced to an exact solution for an infinite dielectric slab. For 2D, or 3D scatterers, the formulation is verified numerically. Especially fur edge-on TM polarized wave incidence a closed-form solution of backscattering from a thin dielectric half-plane is formulated, which is very accurate for wide range of normalized surface impedance except very low impedances(│η│〈0.5).