• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.241-245
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• 2002

Dual-band microstrip antenna is designed for industrial-scientific-medical(ISM) band of 2.4㎓ and 5.8㎓ using finite-difference time-domain method(FDTD). Cross Patch fed by aperture in the ground plane of microstrip line is proposed as radiation element of antenna, which is 2 rectangular Patch is overlapped. To design antenna, change of input impedance by aperture and stub length change is examined. And it is investigated that center frequency and -10 ㏈ bandwidth by Length of radiation element and width change. Experimental result about reflection Loss confirmed that agree well with analysis results of FDTD and IE3D, And -3 ㏈ beam width, front to back ratio and gain in frequency 2.43㎓ and 5.79㎓ is presented by measuring radiation Pattern of antenna.

• International Journal of CAD/CAM
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• v.3 no.1_2
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• pp.43-50
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• 2003

This paper presents a methodology in which the knowledge of design intents and change requests is communicated unambiguously cross collaboration partners through features. The domain of application is focused on the plastic part design for enabling effective collaboration between the product design and plastic mold making. The methodology takes the feature-based design approach and allows design features and knowledge to be reused in plastic injection mold design. It shortens the mold design lead-time, reduces mold design efforts, and enables unambiguous and fast design change management between product and mold designers. These contribute to the reduction of product development cycle time.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.10
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• pp.1150-1157
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• 1988

In this paper, the reconstruction of complex permittivity distribution on a rectangular cross section of inhomogeneous dielectric cylinders is performed by employing the spectral inverse scattering scheme presented in the part I of these companion papers. Numerical simulations provide the superresolution to the permitivity profiles nearly regardless of the measurement locations of the scattered field and the permittivity distributions on the cross section.

• Korean Journal of Optics and Photonics
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• v.5 no.1
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• pp.152-157
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• 1994

A fiber-optic interferometric sensor array capable of passive remote sensing is demonstrated with two sensors at the array head. The signal from a specific sensor could be separated in time domain. The measured sensitivity at signal frequencies of a few kHz and cross talk level between two sensors were about $40{\mu}rad\sqrt{Hz}$and below - 50 dB, respectively.tively.

• Journal of the Korea Computer Industry Society
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• v.2 no.6
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• pp.845-852
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• 2001

Electronic commerce and application service is to universal on the internet, and a large quantity information transmitted on the network, It's needs procedure to access only permit objects for the integrity of information. In order to provide regional services is authentication for control resource and client identification. In particular, public key system is to implement in distributed environment, it is able to insurance users convenience and integrity at the same time. In this paper designed mechanism of cross certification between realms in PKI based on X.509 associated with DNS (Domain Name System) that is presented.

• Nuclear Engineering and Technology
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• v.47 no.3
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• pp.284-292
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• 2015

A numerical calculation with the commercial computational fluid dynamics code CFX-14.0 was conducted for a test facility simulating the Canadian deuterium uranium moderator thermal-hydraulic. Two kinds of moderator thermal-hydraulic tests at Stern Laboratories Inc. were performed in the full geometric configuration of the Canadian deuterium uranium moderator circulating vessel, which is called a calandria tank, housing a matrix of horizontal rod bundles simulating calandria tubes. The first of these tests is the pressure drop measurement of a cross flow in the horizontal rod bundles. The other is the local temperature measurement on the cross section of the horizontal cylinder vessel simulating the calandria system. In the present study, the full geometric details of the calandria tank are incorporated in the grid generation of the computational domain to which the boundary conditions for each experiment are applied. The numerical solutions are reviewed and compared with the available test data.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.163-166
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• 2000

The design, numerical simulation, and an experimental implementation of two-element cross-shaped microstrip line-fed printed slot array antenna for IMT-2000 at the 2.0 GHz band is presented in this paper. The proposed antenna with relative permittivity 4.3 and thickness 1.0mm is analyzed by the Finite-Difference Time-Domain (FDTD) method. It was shown that the measured 2.0 VSWR bandwidth of one-element microstrip slot antenna is from 1.42 GHz to 2.69 GHz, which is approximately 61.8% and that of two-element microstrip slot array antenna is from 1.42 GHz to 2.56 GHz, which is approximately 57.3% And it was shown that the measured gain of one-element microstrip slot antenna is 2.75 dBi and that of two-element microstrip slot antenna is 4.75 dEi. The antennas were fabricated and tested. The measured results are in good agreements with the FDTD results.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.183-186
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• 2000

We analyzed the cross-shaped microstripline-fed slot antenna with the reflector using FDTD(Finite-Difference Time-Domain) method in this paper. The proposed antenna uses RR Duroid-5880 substrate(relative permittivity 2.2 and height(1.578 mm) of dielectrics), and compares the optimized results of other kind substrates. The maximum bandwidth of the proposed antenna is from 1.91 GHz to 5.21 GHz, which is approximately 1.437 octave for the VSWR $\leq$ 2. It was found that the bandwidth of the antenna depend highly on the length of the horizontal and vertical feedline as well as the offset position of the feedline. The experimented data for the VSWR and the radiation pattern of the antenna are also represented.

• Structural Engineering and Mechanics
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• v.80 no.5
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• pp.625-643
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• 2021

In this paper, we present a new method to calculate interface warping functions for the analysis of beams with geometric and material discontinuities in the longitudinal direction. The classical Saint Venant torsion theory is extended to a three-dimensional domain by considering the longitudinal direction. The interface warping is calculated by considering both adjacent cross-sections of a given interface. We also propose a finite element procedure to simultaneously calculate the interface warping function and the corresponding twisting center. The calculated interface warping functions are employed in the continuum-mechanics based beam formulation to analyze arbitrary shape cross-section beams with longitudinal discontinuities. Compared to the previous work by Yoon and Lee (2014a), both geometric and material discontinuities are considered with fewer degrees of freedom and higher accuracy in beam finite element analysis. Through various numerical examples, the effectiveness of the proposed interface warping function is demonstrated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.5
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• pp.479-488
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• 2003

Dual-band microstrip antenna is designed for industrial-scientific-medical(ISM) band of 2.4 GHz and 5.8 GHz using finite-difference time-domain method(FDTD). Cross patch 130 by aperture in the ground plane of microstrip line is proposed as radiation element of antenna which is 2 rectangular patch is overlapped. To design antenna, change of input impedance is examined by length change of aperture and stub. And center frequency and - 10 dB bandwidth are investigated by change of length and width in radiation element. Measured result about reflection loss confirm that agree well with simulation results of FDTD and IE3D. And 3 dB beam width, front to back ratio and maximum gain is presented by measuring radiation pattern of antenna in frequency 2.43 GHz and 5.79 GHz.