• Atmosphere
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• v.21 no.3
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• pp.311-317
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• 2011

Aerosol optical properties from the radiation measurements by SKYNET PREDE skyradiometers, POM-01 and POM-02 were compared during the inter-calibration campaign at Seoul in February 2009. The monochromatic solar flux at the top of the atmosphere ($F_0$) gave a relative standard deviation (RSD) of 9-10% for both instruments. This comparatively high value of RSD was probably because $F_0$ was determined at short time intervals, in the morning and afternoon, using the measurements made in the polluted environment of Seoul. Although POM-02 was more effective in tracking the solar radiation, aerosol optical depths (AODs) from the two instruments were very similar after the cloud screening procedure. The squared correlation coefficients ($R^2$) of single scattering albedo (SSA) and real and imaginary refractive indices between the two instruments was around 0.5 but increased to 0.7-0.8 when only using AOD greater than 0.4. Nevertheless, mean values of the Angstrom exponent, SSA, and the imaginary refractive index of POM-02 were higher than those of POM-01.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1431-1440
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• 2024

The study aimed to develop a laser-based distance meter (LDM) to improve water surface identification for clinical MeV electron beam dosimetry, as inaccurate water surface determination can lead to imprecise positioning of ionization chambers (ICs). The LDM consisted of a laser ranging sensor, a signal processing microcontroller, and a tablet PC for data acquisition. I₅₀ (the water depth at which ionization current drops to 50 % of its maximum) measurements of electron beams were performed using six different types of ICs and compared to other water surface identification methods. The LDM demonstrated reproducible I₅₀ measurements with a level of 0.01 cm for all six ICs. The uncertainty of water depth was evaluated at 0.008 cm with the LDM. The LDM also exposed discrepancies between I₅₀ measurements using different ICs, which was partially reduced by applying an optimum shift of IC's point of measurement (POM) or effective point of measurement (EPOM). However, residual discrepancies due to the energy dependency of the cylindrical chamber's EPOM caused remained. The LDM offers straightforward and efficient means for precision water surface identification, minimizing reliance on individual operator skills.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1350-1358
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• 2013

For this study, in order to understand the perception level of foot reflex therapy and clarify its related factors among customers using foot care service centers, a survey was conducted based on structured self-administered questionnaire with 181 users of three foot care service centers located in Daejeon between September 1 and October 30, 2011. The results showed that the average score in perception level of the subjects regarding foot reflex therapy was $32.19{\pm}5.32$(Score scale of the 11 items 0-44) and people with higher level of education had a significantly higher perception level(p=0.020).The perception level based on attitude and practice of foot reflex therapy was significantly higher in the group who do it "to heal illness"(p=0.034); and who "had illness" at the time when they started the therapy (p=0.030); when they used the foot massage for a longer period (p=0.000); and those in the group who would "recommend it"(p=0.004). In multiple regression analysis, among the factors that affect perception level of foot reflex massage, reason for using foot reflex therapy, health state when starting foot reflex massage, period of using foot reflex massage, and experience of recommendation to other people were selected as significant variables, with the explanatory power of 26.1%. The results suggest that perception level of foot care service users regarding foot reflex therapy are more correlated to variables that explain their attitude and practice than general characteristic variables.