• Title/Summary/Keyword: Information Communications Technology

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Study on the Forest Observation in Kushiro Wetland by using Dual-Frequency and Fully Polarimetric Airborne SAR (Pi-SAR) Data

  • Nakamura Kazuki;Wakabayashi Hiroyuki;Shinsho Hisashi;Maeno Hideo;Uratsuka Seiho;Nadai Akitsugu;Umehara Toshihiko;Moriyama Toshifumi
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.405-409
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    • 2004

  • We chose the Kushiro wetland in Hokkaido, Japan, as a test site to monitor wetland areas. Synthetic aperture radar (SAR) can carry out continuous observation in any weather conditions, and can therefore be used to observe high humidity areas such as wetlands. We applied multi-parameter SAR data (dual-frequency, multi-polarization, and multi-incidence angle) to monitoring the wetland forest. To find the optimum incidence angle and polarization for monitoring the wetland biomass, a simple backscattering model of wetland vegetation was developed and applied to estimate backscattering coefficients for different biomass and surface conditions.

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Mode Analysis and Modal Delay Measurement of a Few-Mode Fiber by Using Optical Frequency Domain Reflectometry

  • Ahn Tae-Jung;Moon Sucbei;Youk Youngchun;Jung Yongmin;Oh Kyunghwan;Kim Dug Young
    • Journal of the Optical Society of Korea
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    • v.9 no.2
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    • pp.54-58
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    • 2005

  • A novel mode analysis method and differential mode delay measurement technique for a multimode optical fiber based on optical frequency domain reflectometry has been proposed for the first time. We have used a conventional OFDR with a tunable external cavity laser and a Michelson interferometer. A few-mode optical multimode fiber was prepared to test our proposed measurement technique. The differential mode delay (DMD) of the sample fiber was measured to be 16.58 ps/m with a resolution of 1.5 ps/m. We have also compared the OFDR measurement results with those obtained using a traditional time-domain measurement method.

  • https://doi.org/10.3807/JOSK.2005.9.2.054 인용 PDF KSCI

Rain Rate Estimation Process Using Doppler Spectrum of UHF Wind Profiler Radar

  • Kitichai Visessiri;Chaiwat Somboonlarp;Anuchit Waisontia;Lee, Nipha laruji;Narong Hemmakon
    • Proceedings of the IEEK Conference
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    • 2002.07c
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    • pp.1575-1577
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    • 2002

  • In this research we propose a method far rain rate estimation by using Doppler spectrum's data of wind profiler. The Doppler spectrum is used to calculate the wind velocity and wind direction. But in this research uses the parameters from Doppler spectrum, it calculates the rain rate. The rain rate estimation in this method will be compared to the obtained rain rate from the surface rain gauge. Two equipments are installed in the same area. The correlation coefficient between rain rate measuring method is 0.65.

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Concentration optimization of Tb/Yb co-doped alumino-germanosilicate optical fiber for upconversion visible laser applications

  • Lin, Aoxiang;Watekar, Pramod R.;Liu, Xueming;Cho, Hye-Jin;Chung, Young-Joo;Han, Won-Taek
    • Proceedings of the Optical Society of Korea Conference
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    • 2008.02a
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    • pp.249-250
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    • 2008

  • We report on the visible photoluminescence of the Tb/Yb co-doped alumino-germano-silicate fibers for visible fiber laser application. By changing the concentration ratios of $Tb^{3+}$ to $Yb^{3+}$, we optimized the solution doping conditions and obtained the highest emission efficiency at 546nm. The luminescence intensity at 546nm was found to increase with the relative increase of $Tb^{3+}$ ions.

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