• ETRI Journal
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• v.31 no.3
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• pp.321-323
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• 2009

A wideband beamforming algorithm for estimating the azimuth angle, elevation angle, velocity, and range using a planar phased radar array with antenna switching is proposed. It uses the time-variant steering vector model. Simulation results illustrating the performance of the proposed beamformer are presented.

• Journal of applied mathematics & informatics
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• v.4 no.1
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• pp.235-242
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• 1997

We characterize the tight structure of a vertex-accumula-tion-free maximal planar graph with no separating triangles. Together with the result of Halin who gave an equivalent form for such graphs this yields that a tight structure always exists in every 4-connected maximal planar graph with one end.

• Journal of applied mathematics & informatics
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• v.27 no.3_4
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• pp.531-539
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• 2009

In this paper we first present a structure theorem for an infinite locally finite 3-connected VAP-free planar graph, and in connection with this result we study a possible classification of infinite locally finite planar graphs by reducing modulo finiteness.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.12 no.1
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• pp.7-11
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• 2008

The energy of a graph is the sum of the absolute values of its eigen values. We obtain some bounds for the energy of planar graphs in terms of its vertices, edges and faces.

• Journal of the Chungcheong Mathematical Society
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• v.20 no.1
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• pp.71-80
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• 2007

In this article, we consider axes of a minimal surface in $R^3$ of genus zero with a planar end, and then prove that two consecutive axes near planar end must be parallel but cannot be in a same line.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2114-2116
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• 2004

센서의 소형화 되는 추세에 전극 면적은 sensitivity의 중요한 요인이다. 본 연구에서는 콜레스테롤을 측정하기 위해 각각 planar 전극과 porous 전극에 효소 고정화 방법으로 covalent binding인 silanization 공정을 이용하여 전극 면적에 따른 전기화학적 감도를 비교하였다. Handles-Sevcik equation을 이용하여 전극 면적을 구한 결과 planar 전극의 경우 0.1608 $cm^2$, porous 전극의 경우 0.5054 $cm^2$로 porous 전극 면적이 planar전극에 비해 약 3.1배 증가하였다. 또, planar 센서의 sensitivity는 0.08567 ${\mu}A/mM{\cdot}cm^2$이고 porous 센서의 sensitivity는 planar sensor에 비해 약 3.1배 증가한 0.2656 ${\mu}A/mM{\cdot}cm^2$였다. 따라서 porous sensor의 sensitivity의 증가는 전극 면적의 증가에 따른 것이라고 할 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.681-686
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• 2003

In this paper, we propose an algorithm to extract valid planar regions from stereo images for visual navigation of mobile robots. The algorithm is based on the difference image between the stereo images obtained by applying Homography matrix between stereo cameras. Illegal planar regions are filtered out by the use of labeling of the difference images and filtering of invalid blobs using the size of each blob. Also, illegal large planar regions such as walls are removed by adopting a weighted low-pass filtering of the difference image using the past difference images. The algorithms are experimented successfully by the use of stereo camera system built in a mobile robot and a PC-based real-time vision system.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.804-809
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• 2004

It is essential to calibrate a camera in order to recover 3-dimensional reconstruction from uncalibrated images. This paper proposes a new technique of the camera calibration using a homography between the planar patterns image taken by the camera, which is located at the three planar patterns image. Since the proposed method should be computed from the homography among the three planar patterns from a single image, it is implemented more easily and simply to recover 3D object than the conventional. Experimental results show the performances of the proposed method are the better than the conventional. We demonstrate the examples of 3D reconstruction using the proposed algorithm from image sequence.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.167-172
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• 2002

Recent years, optical components'are widely used in optical communication industry for high speed and mass storage data processing. Micro grooving of planar lightwave circuit and glass, those are widely used in optical component, are realized by polycrystalline diamond tool with ultrasonic vibration. To know the characteristics of brittle materials cutting, ultrasonic vibration cutting tool and machining system are built for the experiment. Grooving on planar lightwave circuit and glass experiments are performed and their shape are measured by photograph with microscope. It reveals that better groove shape with low chipping of planar lightwave circuit and glass are obtained by micro grooving machining with ultrasonic vibration. These experiments are considered as a possibility to the micro grooving of optical communication components.

• Journal of electromagnetic engineering and science
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• v.5 no.4
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• pp.153-160
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• 2005

In this paper, the novel microwave oscillator incorporating a planar cavity resonator(PCR) is presented to reduce the phase noise of the oscillator in a planar environment. Compared to the conventional planar( $\lambda$/4 open stub resonator), the phase noise is improved about 16 dBc/Hz @100 kHz. The design of the oscillator is based on a reflection type configuration using the low 1/f SiGe HBT transistor(LPT16ED). The output power is measured 2.76 dBm at 12.5 GHz. In this paper, the oscillator used to the PCR can be expected to provide a solution for low phase noise oscillator in microwave circuits.