• Progress in Medical Physics
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• v.17 no.3
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• pp.131-135
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• 2006

A commercial ion chamber matrix was examined the characteristics and its performance for radiotherapy qualify assurance. The device was the I'mRT 2D-MatriXX (Scanditronix-Wellhofer, Schwarzenbruck, Germany). The 2D-MatriXX device consists of a 1020 vented ion chamber array, arranged in $24{\times}24cm^2$ matrix. Each ion chamber has a volume of $0.08cm^3$, spacing of 0.762 cm and minimum sampling time of 20 ms. For the investigation of the characteristics, dose linearity, output factor, short-term reproducibility and dose rate dependency were tested. In the testing of dose linearity. It has shown a good signal linearity within 1% in the range of $1{\sim}800$cGy. Dose rate dependency was found to be lower than 0.4% (Range: 100-600 Mu/min) relative to a dose rate of 300 Mu/min as a reference. Output factors matched very well within 0.5% compared with commissioned beam data using a ionization chamber (CC01, Scanditronix-Wellhofer, Schwarzenbruck, Germany) in the range of field sizes $3{\times}3{\sim}24{\times}24cm^2$. Short-term reproducibility (6 times with a interval of 15 minute) was also shown a good agreement within 0.5%, when the temperature and the pressure were corrected by each time of measurement. in addition, we compared enhanced dynamic wedge (EDW, Varian, Palo Alto, USA) profiles from calculated values in the radiation planning system with those from measurements of the MatriXX. Furthermore, anon-uniform IMRT dose fluence was tested. All the comparison studies have shown good agreements. In this study, the MatriXX was evaluated as a reliable dosimeter, and it could be used as a simplistic and convenient tool for radiotherapy qualify assurance.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.1
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• pp.96-105
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• 2011

This study analyzed literary works and references related to Dok-Rak-Dang(獨樂堂) and the attributes of managing the landscape in Dok-Rak-Dang Garden based on the assumption of position and the spatial structure revealed in the site. Hoe-Jae Lee Eon-Jeok(1491-1553), a distinguished scholar of Neo-Confusionism, built Dok-Rak-Dang and managed the surrounding areas during his retirement years. He called the mountains, stream, and rock along and near the Ja-Ge Stream Four Mountains and Five Platforms(四山五臺). Before he named these, they were not considered special. The Four Mountains which are Do-Duk in north, Mu-Hak in south, Hwa-Gae in east, and Ja-Ok in west enclose Dok-Rak-Dang and the surrounding areas. The Five Platforms, Se-Sim, Gwan-Eo, Yeong-Gue, Jing-Sim, and Tak-Yeong, in order from downstream, are places with beautiful scenery in Ja-Ge Stream. The attributes of managing the landscape in Dok-Rak-Dang Garden are the following: One is the spatial integration of what is natural and artificial as the attitude of aesthetic experience in accord with nature. Another is flexible territorialization as the way of organizing spaces in nature from the experiential aspect. The other is place making of personalized nature through a series of processes such as observing, choosing, and naming landscapes in nature. Four Mountains and Five Platforms function as landscape bases and elements to appreciate nature aesthetically. Those attributes are different from the attitude of constructing spaces. Rather, they originate from the traditional view on the appreciation of nature. Above all, place-making in nature was acquired from designed spatial structure and experiential aesthetic appreciation in the space through observing, choosing, and naming landscapes in nature reflecting creator's own ideological and aesthetic thoughts, and it might be explained as one of practical ways of Korean traditional gardening.