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오일덕 한국통신학회 1994 韓國通信學會論文誌 Vol.19 No.6
위성을 이용한 이동통신시 도로 주변의 가로수가 신호감쇠의 주요 원인이 된다. 이러한 가로수로 인한 신호감쇠를 해석하기 위하여 가로수를 구형장애물들의 조합으로 모델화 시키고, 가로수 모델에 대한 신호세기의 변화를 Frensnel 및 Kirchhoff 회적이론을 근거로 유도하였다. 가로수 모델에 의한 신호감쇠를 송.수신 거리, 송.수신 단의 위치 및 고도각을 변화시켰을 때의 이론치를 수치해석적으로 계산하여 실험치와 비교하였다. 이론치와 실험치와를 비교한 결과 신호감쇠 경향이 일치함을 볼 수 있었다. In this case of the mobile communication of vehicles with satellite, the signal at attenuation is due to roadside trees. To analyze this signal attenuation, a roadside tree was modeled as different obstacles of rectangular type and then using Fresnel and Kirchhoff diffraction theory, a formula was derived for signal intensity variation caused by the roadside tree model. The signal attenuation of a roadside tree model was obtained by numerical analysis with variation of the elevation angle, the position and distance between a receiver and a transmitter, and these were compared with experimental results. The results of comparison between theoretical and experimental values show, as expected, the good agreement of the signal attenuation trend.
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吳一德 大田産業大學校 1996 한밭대학교 논문집 Vol.13 No.1
Field intensity is affected by various parameters, including the frequency, distance, antenna height, atmospheric conditions, and the shape of obstacles and apertures in mobile communication. Using the Fresnel-Kirchhoff diffraction theory a formular is derived for signal intensity variation caused by rectangular obstacles and the signal intensity according to parameter variation of rectangular obstacles is numerically calculated on the basis of the theory in this paper. Assuming that a tree model consists of many different obstacles of rectangular type, 漁e signal attenuation of some overlapped by Tree model is obtained by numerical analysis with variation of the position and distance between a receiver and a transmitter, and these were compared with experimental results.
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吳一德 大田産業大學校 1994 한밭대학교 논문집 Vol.11 No.0101
In mobile-radio communication system the field intensity of electromagnetic wave varies with frequency, shape of antenna, location of on obstacle and distance from obstacles to a transmitter and receiver. Formulas in previous papers on this system were mostly approximated on the experimental data. In this paper, the diffraction phenomena on electromagnetic wave for a complexed rectangular obstacles is analysed by using Huygens-Fresnel diffraction theory and a new theoretical diffraction theory on apertures was derived. The signal intensity in variation of a complexed rectangular obstacles's parameters is numerically calculated by a computer. These results will be used to predict signal attenuation due to the obstacles which appear between base station and mobiles in urban areas or between the satellite and moving vehicles on the road.
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吳一德,李南柱 大田産業大學校 1998 한밭대학교 논문집 Vol.15 No.1
In this paper, we discussed the coupling theory on fiber Bragg grating(FBG), techniques, and characteristic analyses of the fabricated specirrens When the writing energy of excimer laser is low(300[mJ/pulse] and the pulse width is 20[nsec]), the peak reflectance and peak wavelength steadily increases as the number of shots of writing UV pulse increases. This result and theoretical analysis is well coincided. The variation of average refractive index and the index modulation depth of FBG is analyed from this result. When the writing energy of excimer laser is high enough(more than 390[mJ/pulse]), FBG with higher than 99[%] reflectance is fabricated by only one shot of writing wavelength. It seems that this grating is formed by asymmetric damage at clad-core interface.
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吳一德 大田工業專門大學 1983 論文集 Vol.33 No.-
In this paper, the signal separated circuit which is simple and stabilized is designed by simple TTL ICs. In this signal separated circuit, trigger input signals with each other frequency are separate by counter IC and decoder IC and turn into delayed output by delay circuit. When there is no signal input, counter circuit is reset by the reversing transistor with counter stopped and without interrupting already entered signals. As a result this circuit is designed to control terminals with each other use.
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赤外線 Diode를 利用한 Remote Control Logic Key의 設計에 關한 硏究
吳一德 大田工業專門大學 1984 論文集 Vol.34 No.--
Since many kinds of mechanical lock had low reliabilities, lately we have studied the logic key method using Integrated Circuits. Such a logic key can increase more reliabilities as it can count the numbers by switching operation of pus h buttons and change those by using various decoders. But . in that case, the push button switch was likely to be put out of order and it had many problems as like short life. For improving these defects , remote control methods using infrared diodes are studied in this paper . This is not to modulate signal wave with infrared rays. but how to transmit infrared pulse by switching of it's signal, The method has increased reliability in control of TV or audio systems . This paper described in detail each parts of infrared transmitter , receiver and logic key circuits which used simple TTL. ICs . Particulary, to increase the reliability. error detection circuit by 2-step counter method was added , and circuit elements to simplify the circuits and have stable operation were chosen and designed.
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吳一德 大田開放大學 1986 論文集 Vol.5 No.-
This paper implemented memory access with simple logic circuit which it could be access the course of data itself. The number of accessing data is depending upon the effectiveness of its position of item and search Algorithm used. Each cell of the associative memory realized with the simplest logic circuit and could be identified the process of performing in memory by the variable length data.
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