• Journal of the Korean Institute of Gas
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• v.18 no.5
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• pp.60-65
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• 2014

The flash point is the major physical property used to characterize the fire hazard of flammable liquid solutions. In the present study, the main focus is on measuring and estimating the flash points for binary flammable mixture. The flash points for n-propanol+propionic acid were measured by Seta flash closed cup apparatus. The experimental data were correlated with the van Laar and NRTL equations through the optimization method. The results estimated by these correlations were compared with the values calculated by the method based on Raoult's law. The optimization method were found to be better than the method based on the Raoult's law.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.888-894
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• 2015

Inorganic composite particles have excellent physical and chemical characteristics and have been applied in various industries. Recently, many studies have examined the optical properties, such as light scattering, refraction, transmission characteristics, by coating organic-inorganic materials on a substrate, such as mica. Mica is widely applied as a pigment, plastics, painted products, and ceramics because of its high chemical stability, durability and non-toxicity. Magnesium oxide has a range of properties, such as high light transmittance, corrosion resistance and non-toxicity, and it is used as an optical material and polymer additives. To use the optical properties of mica and magnesium oxide, mica was coated with magnesium hydroxide by a dissolution and recrystallization process. In this study, the optimal conditions for the haze value of the particles were found by adjusting the amount of precursors and pH. Magnesium hydroxide layers were formed on the surfaces of mica and converted to MgO after calcination at $400^{\circ}C$ for 4 h. The results showed that the value of MgO-coated mica haze can be controlled easily by the amount of the magnesium hydroxide and pH. The optical properties of the inorganic composite powder were analyzed using a hazemeter and the highest haze value was 85.92 % at pH 9. The physicochemical properties of the synthesized composite was analyzed by SEM, XRD, EDS, and PSA.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.1118-1123
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• 2009

Ten hospitals from the Gwangju area were used to examine shallow dose to eyes and thyroid from panoramagraphy. Thermoluminescent dosimeter (TLD) and Photoluminescent dosimeter (PLD) were used as measurement devices at each hospital. ICRP 60 and ICRP 73 set standards for acceptability for eyes at 15mSv and thyroid at 1mSv per year. Left eye measures with TLD and PLD resulted in 0.19mSv and 0.24mSv respectively. Right eye measures with TLD and PLD resulted in 0.23mSv and 0.25mSv respectively. Thyroid measures with TLD and PLD resulted in 0.08mSv and 0.25mSv respectively with both measures not exceeding standards for acceptance. There was a significant difference in comparing the left eye and thyroid for TLD and PLD (p<0.01). There was no significant difference with the right eye (p>0.05). The absorbed dose measurements for eyes and thyroid using TLD and PLD in regards to panorama devices at each hospital were within the ICRP 60 recommendations; however, with the possibility of stochastic effect, all dose levels were taken into consideration.

• Journal of Korean Home Economics Education Association
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• v.29 no.4
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• pp.49-64
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• 2017

The purpose of this study was to explore ways to help improve adolescents' happiness by exploring the influences of emphatic ability and family strengths on happiness. This subjects were 514 middle school students living in Gwangju. Data were collected from self-report questionnaires and analyzed with SPSS 22.0 program. The major findings were as follows; First, the adolescents' emphatic ability('viewpoint', 'identity', 'emphatic interest'), family strengths('family respect and affection', 'role sharing and problem solving', 'communication and bonds', 'financial stability') and happiness scores were higher than the median(3.00). Emphatic ability('viewpoint', 'identity', 'emphatic interest', 'personal suffering') and family strengths('communication and bonds') showed significant difference according to gender. Second, the adolescents' happiness was influenced by 'family respect and affection', 'role sharing and problem solving', 'financial stability', 'personal suffering', 'identity', and 'emphatic interest'. Adolescents' happiness was explained about 39% by these variables. In other words, the higher family respect and affection, both higher role sharing and problem solving and higher financial stability, with lower personal suffering and higher identity and higher emphatic interest showed the higher happiness. These findings demonstrate the emphatic ability and family strengths in adolescents influence on the level of happiness. As such, in order to improve the happiness of adolescents, it is necessary to energize those programs focus on the forming healthy family relationships and to design finance assistance programs that could attempt to minimise financial gap. Additionally, it is necessary to develop programs aimed to enhance emphatic ability and continue such programs in homes as well as at schools. Finally, it is necessary to implement curriculum that may improve family strengths and emphatic ability, which have influenced on the happiness in adolescents. Since the subject "Technology & Home Economics" helps to enhance family strengths, emphatic ability and eventually amplifies the happiness, it is necessary to expand and reinforce it as well as to make it a mandatory subject.

• Journal of Broadcast Engineering
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• v.19 no.3
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• pp.362-371
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• 2014

Blur variation caused by camera de-focusing provides a proper cue for depth estimation. Depth from Defocus (DFD) technique calculates the blur amount present in an image considering that blur amount is directly related to scene depth. Conventional DFD methods use two defocused images that might yield the low quality of an estimated depth map as well as a reconstructed infocused image. To solve this, a new DFD methodology based on infocused and defocused images is proposed in this paper. In the proposed method, the outcome of Subbaro's DFD is combined with a novel edge blur estimation method so that improved blur estimation can be achieved. In addition, a saliency map mitigates the ill-posed problem of blur estimation in the region with low intensity variation. For validating the feasibility of the proposed method, twenty image sets of infocused and defocused images with 2K FHD resolution were acquired from a camera with a focus control in the experiments. 3D stereoscopic image generated by an estimated depth map and an input infocused image could deliver the satisfactory 3D perception in terms of spatial depth perception of scene objects.

• Journal of Environmental Impact Assessment
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• v.25 no.3
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• pp.175-189
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• 2016

The guideline for railway noise mapping is notificated in the administration law for noise/vibration which is announced by the ministry of environment, Korea. Here input parameters for the railway sound sources are proposed for each prediction models. In case of the application of the vehicle characteristics it is suggested to choose "0(%)" for the disc brake parameter. However new trains have been in revenue service since the announcement of the guideline, an investigation of the effect of the input parameters of the foreign railway prediction models on the prediction results of korean railway systems are needed. In this paper the sound prediction results are analyzed with a focus on the input parameters such as disc brake percentage, rail roughness, rail joints. Schall03 is used for the railway noise prediction which has been using most frequently in Korea. The results are shown and discussed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6C
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• pp.505-511
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• 2008

The global navigation satellite system (GNSS) is using a direct sequence/spread spectrum (DS/SS) modulation. In order to recover the information data, the DS/SS system first performs a two-step synchronization process: acquisition and tracking. The acquisition process adjusts the phase difference between the received and locally generated acquisition sequences within ${\pm}T_c/2$ or less, where $T_c$ is the chip period. The tracking process performs fine synchronization. In this paper, we focus on the tracking issue. The single delta delay locked loop($\Delta$-DLL) is the optimal tracking scheme for a GNSS in the absence of multipath signals, where $\Delta$ means the spacing between the early and late correlation time offset. In the multipath environments, however, the $\Delta$-DLL suffers from huge estimation bias(denoted by $\beta$) caused by distorted correlation values. Although some modified schemes such as a $\Delta$-DLL with a narrow $\Delta$ and a double delta DLL (${\Delta}^{(2)}$-DLL) were proposed to reduce the estimation bias, they cannot remove the estimation bias completely and need more accurate acquisition process. This paper proposes a novel tracking scheme that can dramatically reduce the estimation bias, using the maximum slope change among the correlation outputs.

• Journal of Conservation Science
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• v.34 no.6
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• pp.503-515
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• 2018

Stupa of State Preceptor Jigwang at Beopcheonsa temple site, Wonju, was conserved and restored in 1957. It was necessary to assess the degree of damage to the used mortar and to provide objective data on the necessity of its removal. Therefore, the HCP(half-cell potential) measurement used in concrete fields was applied. Multi-regression analysis of HCP data, following the rapid corrosion test of the roofstone mortar used by the rebar, resulted in a high correlation of HCP values(0.86), depending on the amount of corrosion and cover depth used for the steel bar. As a result, high correlation values(0.86) for the coefficients of determination were derived. The showed that the measurement of the wet conditions -431 to -663 mV on the roofstone indicated a corrosion damage rate of 90% or more after removal and restoration.

• 한국노년학
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• v.40 no.1
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• pp.147-161
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• 2020

The purpose of this research is to investigates 10-year trajectories of cognitive functions among older adults in their 70s to understand changes in cognitive functions as a continuum until very late life. This study also examines differences in trajectories of cognitive functions by gender and by changes in marital status, especially widowhood. Among participants of the Korean Longitudinal Study of Ageing(KLoSA), the sample of this study includes 800 older adults in their 70s during the first study wave (2006) and those who reported their cognitive functions for six consecutive study waves (2006, 2008, 2010, 2012, 2014, and 2016). The analyses were conducted in two steps. First, we conducted Latent Class Growth Analyses(LCGA) to investigated heterogeneous trajectories of cognitive functions in 10 years. Then, we performed multinomial logistic regression. Three heterogeneous trajectories of cognitive functions were identified. One group of 48.7% of older adults showed high cognitive function at baseline and maintained it over 10 years. Second group of 14.7% of older adults reported low cognitive function scores at baseline and showed continuous decline over time. Third group of 36.6% were showed mid-level cognitive functions and maintained their functions over time. We also found significant gender differences but not significant differences in marital status when we consider both in our model; however, the we found significant differences in changes in marital status when we did not consider gender in the model. The results suggest that the importance of considering dynamics of gender and changes in marital status to understand changes in cognitive functions in later life.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.2
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• pp.156-172
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• 2014

This research measures and compares on-site net radiation energy, air temperature, wind speed, and surface temperature considering various spatial characteristics with a focus on land use types in urban areas in Changwon, Southern Gyeongsangnam-do, to analyze the accuracy of an ENVI-met model, which is an analysis program of microclimate. The on-site measurement was performed for three days in a mobile measurement: two days during the daytime and one day during the nighttime. The analysis using the ENVI-met model was also performed in the same time zone as the on-site measurement. The results indicated that the ENVI-met model showed higher net radiation than the on-site measurement by approximately $300Wm^{-2}$ during the daytime whereas the latter showed higher net radiation energy by approximately $200Wm^{-2}$ during the nighttime. The temperature was found to be much higher by approximately $2-6^{\circ}C$ in the on-site measurement during both the daytime and nighttime. The on-site measurement also showed higher surface temperature than the ENVI-met by approximately $7-13^{\circ}C$. In terms of the wind speed, there was a significant difference between the results of the ENVI-met model and on-site measurement. As for the correlation between the results of the ENVI-met model and on-site measurement, the temperature showed significantly high correlation whereas the correlations for the net radiation energy, surface temperature, and wind speed were very low. These results appear to be affected by excessive or under estimation of solar and terrestrial radiation and climatic conditions of the surrounding areas and characteristics of land cover. Hence, these factors should be considered when applying these findings in urban and environment planning for improving the microclimate in urban areas.