• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1605-1608
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• 1997

In this paper, a new onmidirectional robot with one spherical wheel is porposed. The peculiar structure of the proposed mobile robot makes it possible not only to move sideways but to be easy to implement. The wheel is derived by two stepping motors and equipped with 8-infrared sensors. To prove the validity of the proposed robot, the experiment of going through a way is performed.

• The Journal of the Acoustical Society of Korea
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• v.17 no.1E
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• pp.14-19
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• 1998

This article describes the application of a coupled finite element-boundary element method to obtain the steady-state response of a sonar transducer. The sonar shell is simulated to be driven by electrical charges applied onto inner and outer surfaces of the shell. It is shown that at relatively low input frequency a beam pattern which is almost close to omnidirection can be obtained. The coupled FE-BE method is described in detail.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.1
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• pp.37-43
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• 1998

This article describes the application of a coupled finite element-boundary element method to obtain the steady-state response of a sonar transducer. The particular structure considered is a flooded piezoelectric spherical shell. The sonar shell is simulated to be driven by electrical charges applied onto inner and outer surfaces of the shell. It is shown that at relatively low input frequency a beam pattern which is almost close to omnidirection can be obtained. The coupled FE-BE method is described in detail.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.626-629
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• 2004

Texture imaging, which means texture image creation by co-occurrence relation, has been known as one of useful image analysis methodologies. For this purpose, most commercial remote sensing software provides texture analysis function named GLCM (Grey Level Co-occurrence Matrix). In this study, texture-imaging program for GLCM algorithm is newly implemented in the MS Visual IDE environment. While, additional texture imaging modules based on GLDV (Grey Level Difference Vector) are contained in this program. As for GLCM/GLDV texture variables, it composed of six types of second order texture function in the several quantization levels of 2(binary image), 8, and 16: Homogeneity, Dissimilarity, Energy, Entropy, Angular Second Moment, and Contrast. As for co-occurrence directionality, four directions are provided as $E-W(0^{\circ}),\;N-E(45^{\circ}),\;S-W(135^{\circ}),\;and\;N-S(90^{\circ}),$ and W-E direction is also considered in the negative direction of E- W direction. While, two direction modes are provided in this program: Omni-mode and Circular mode. Omni-mode is to compute all direction to avoid directionality problem, and circular direction is to compute texture variables by circular direction surrounding target pixel. At the second phase of this study, some examples with artificial image and actual satellite imagery are carried out to demonstrate effectiveness of texture imaging or to help texture image interpretation. As the reference, most previous studies related to texture image analysis have been used for the classification purpose, but this study aims at the creation and general uses of texture image for urban remote sensing.

• Journal of Biomedical Engineering Research
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• v.16 no.4
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• pp.543-554
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• 1995

This paper describes the improvement of driving stability and the control system for INMEL-VII which is motorized manual wheelchair to satisfy requirements of the disabled The INMEL-VI was based on high maneuverability of the omnidirection drive and safety But the results of field tests about two years showed some problems to the disabled in daily life such as driving stability, Pm switching noise, and rotation of motor without driving command on negative slope. To solve the problems due to an increased DC motor power and applied to direct connection method in INMEL- VII. It improved the driving circuits and set switching frequency to 5KHz to eliminate the switching noise caused by PWM control of DC motor, As compare with the INMEL-VI, INMEL-VII is improved in driving stability by transfer the weight center to forward. The results of field testing proved the improvement of the driving stability and software algorithm It has been estimated to have a hlgh practical use for powered walking aids to the disabled's daily life.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.4
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• pp.83-94
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• 2021

In this paper, we proposed a microstrip antenna (center frequency 118 MHz) with an omnidirectional radiation pattern that can replace the antennae used in VDB systems in GBAS. First, to obtain an omnidirectional radiation pattern from a microstrip antenna, we constructed a folded antenna. We then designed a miniaturized triple-folded antenna using perturbation effects. Thus we obtained suitable characteristics with a S₁₁ of -13.91dB, -10 dB bandwidth of 1.5 MHz (1.27%) in the center frequency of 118 MHz. Furthermore, in the yz-plane and xy-plane, the component exhibits an omnidirectional radiation pattern, and the size of the antenna achieves miniaturization of 64.2% compared to the reference antenna. Finally, it is suitable as an antenna for VDB systems in GBAS.