• Applied Chemistry for Engineering
• /
• v.27 no.1
• /
• pp.16-20
• /
• 2016

In this work, we describe the synthesis and infrared light reflecting characteristics of $TiO_2$/mica hybrid composites. $TiO_2$/mica composite materials were obtained by the hydrolysis and condensation reaction of titanium isopropoxide in an aqueous solution of acetic acid in the presence of mica particles. Amorphous phase of $TiO_2$ on the surface of mica was converted to the crystalline rutile phase via anatase phase by heat treatment ($600-1000^{\circ}C$, 1-3 h) of $TiO_2$/mica composite materials, and the size of crystals was controlled by heat treatment conditions. Physicochemical properties of mica and $TiO_2$/mica composites were investigated using FE-SEM, ED-XRF, and PXRD. The solar reflectance of $TiO_2$/mica composites in the near IR region (780~2,500 nm) measured using a diffuse reflectance NIR spectrophotometer was 88.6%, which is rather higher than that of calcined pure mica (86.6%). Therefore, $TiO_2$/mica composites can be used as NIR light reflective pigments.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.12
• /
• pp.835-839
• /
• 2012

In recent decades, a lot of noise barriers have been installed along paved road in order to reduce the road induced noise, which increases as traffic volume grows. For better range of sight, transparent noise barriers are widely installed despite of reflecting noise. In this study, the effect of surface shape and pattern of noise barriers on the reduction of reflecting noise was analyzed to maximize the noise reduction. According to the number of shape and pattern, it was observed that there were noise reduction effect as of 0.9~1.5 dB(A). It was found that the spatial field where the noise concentrates or disperses changes according to the width of blocks on the barriers as well. It suggests that there might be possibility of surface shape modification to optimize the noise reduction technology.

• Journal of Technologic Dentistry
• /
• v.31 no.4
• /
• pp.45-52
• /
• 2009

This study is analyzed to conduct better on-site practices with recognizing importance of the clinical practice of Dept. of dental technology and use it as a basic material in the clinical practice. Target people who are students studying dental technology in D college in Daegu were questioned by survey. Study results below 1. Average score of the survey about satisfaction of the operating method of clinical practice shows 3.26. In detail elements, 'credit assignment(10 credits)' is 3.65 as the highest score, 'execution period(vacation)' is 3.50, 'choice of the clinical practice organization' is 3.25, 'measures after practice' is 2.98 and 'pre-education' is 2.98 as the lowest score. 2. Through the real clinical practice, 'experience of new equipments and technology' is 3.64 as the highest score, 'choice of lecturer' is 3.61, 'guidance way' is 3.49, 'contents properness' is 3.44, 'environment of practice organization' is 3.36, 'evaluation way' is 3.35 and 'practical use of the evaluation material' is 3.18 as the lowest score. 3. The average score of survey about satisfaction after clinical practice of the participated students is 3.46 that is higher than both 'satisfaction about operating method(3.26)' about clinical practice of college and 'satisfaction about organization(3.44)' about environment of dental craft organizations and labs, guidance way of lecturer and evaluation. 4. In the improvement of distribution of the clinical practice evaluation, in the 'practice organization: college' viewpoint, '7:3' is 35.77% as the highest response, '6:4' is 25.20%, '8:2' is 22.76% and '4:6' is 16.26 in regular sequence. 5. In site evaluation reflection of clinical practice, 50% reflection is 32.93% as the highest percentage, 60% reflection is 26.83%, 20% reflection is 20.73% and 80% reflection is 6.10% in regular sequence. In attendance score, it shows percentage of reflecting 50% and 40% is 26.98%, students wanting to reflect 30% is 25.40%, reflecting 10% is 20.63% and no reflecting is 0%. In result of the analyzed data, clinical practice has to be studied more in considering that clinical practice is important point in education of Dept. of Dental Technology and also problems in college and on-site practice need improvements.

• Journal of the Korea Society of Computer and Information
• /
• v.11 no.1 s.39
• /
• pp.71-85
• /
• 2006

The environment of computational grid is composed of the LAN/WAN each of which has different efficiency and heterogeneous network conditions, and where various programs are running. In this environment, the role of the resource selection broker is very important because the work of each node is performed by considering heterogeneous network environment and the computing power of each node according to the characteristics of a program. In this paper, a new resource selection broker is presented that decides the number of work processes to be allocated at each node by considering network state information and the performance of each node according to the characteristics of a program in the environment of computational grid. The proposed resource selection broker has three steps as follows. First, the performance ratio of each node is computed using latency-bandwidth-cpu mixture information reflecting the characteristics of a program, and the number of work processes that will be performed at each node are decided by this ratio. Second, RSL file is automatically made based on the number of work processes decided at the previous step. Finally, each node creates work processes by using that RSL file and performs the work which has been allocated to itself. As experimental results, the proposed method reflecting characteristics of a program, compared with the existing (uniformity) and latency-bandwidth method is improved $278%\sim316%,\;524%\sim595%,\;924%\sim954%$ in the point of work amount, work process number, and node number respectively.

• Journal of the Korean earth science society
• /
• v.40 no.1
• /
• pp.86-106
• /
• 2019

The purpose of this study is to develop an astronomy education program reflecting astronomical thinking to be used at science museum and to investigate the effect of the program on the improvement of astronomical thinking ability of high school students. After selecting the components of astronomical thinking through literature studies, we developed an astronomy education program consisting of four stages: demonstration and observation, and question and thinking, support and group discussion, demonstration and assessment. In order to verify the effectiveness of the program, we conducted a covariance analysis on the pre- and post-tests of the experimental group and control group to examine the level of students' thinking before and after using the program in teaching and learning. As a result, it was confirmed that the astronomy education program reflecting astronomical thinking was effective in promoting students' astronomical thinking ability. In particular, this program was effective in enhancing the ability of modeling by reconstructing the observed astronomical phenomenon from the viewpoint of the universe with respect to spatial thinking in the astronomy domain. It was also effective to improve the ability of organizing the system by grasping the relationship between the elements constituting the astronomical system in relation to the system thinking in the astronomy domain. This study is significant in suggesting a specific teaching and learning program to develop students' astronomical thinking.

• Journal of the Korea Convergence Society
• /
• v.12 no.4
• /
• pp.229-236
• /
• 2021

There has been a lot of research on the real estate market, but a lack of research on the supply and demand of housing supply in each region, reflecting the changes in population growth and supply. It is calculated as the transition probability of the Markov chain model by reflecting the data on the number of houses per 1,000 people in the past 35 years and the forecast data for population change by region, in terms of supply (housing) to demand (population) for factors on the real estate market. According to the calculation results of the real estate market by region, the housing supply to the metropolitan area such as Gyeong-gi, Incheon, and Seoul is expected to be insufficient for a considerable period of time, considering the population changes by region. To stabilize the real estate market, it was confirmed that it was necessary to actively apply the differentiation of housing supply by region. It is meaningful in terms of verifying long term trends in the real estate market by region that reflect the prediction of population change, and it is expected that the methods used in this study will be practical through the analysis results using the historical data.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2004.04a
• /
• pp.419-426
• /
• 2004

The national framework data is being constructed by the second plan of NGIS(National geographic information system). However, themes of national framework data are not reflecting various geographic information of marine that demand is increasing. Also, it is mean that national framework data did not consider concept of country which is integrate land and marine. Therefor, this study perform to organize marine framework data through analysis of overseas framework data, and present the composition of national framework data that land and marine are integrated through investigate relationship between national framework data and marine framework data.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2000.10a
• /
• pp.91-97
• /
• 2000

Once a response spectrum is estimated for the site, if there is a need of generating realistic earthquakes time histories considering seismic sources and path effects, one alternative is to use statistical phase characteristics based on real earthquake records other than assuming arbitrary duration and envelope curves. In this study, statistics of group delay times derived from Japanese strong earthquake data were used for phase generation to fully capture the stochastic property of earthquakes. The result shows that simulated earthquake time histories can be generated according to earthquake magnitude and distances with target response spectrum.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2005.10a
• /
• pp.67-83
• /
• 2005

[ $\blacklozenge$ ] Farm equipment market very cyclic - weather, economic factors, import/export markets $\blacklozenge$ Mergers of companies continuing $\blacklozenge$ Major Tractor OEMs have lubricant specifications $\blacksquare$ Their own house branded THF $\blacksquare$ Constant review reflecting the changes in equipment $\blacksquare$ Less interest in approving outside additives/oils for others $\blacklozenge$ Future THF lubricant market $\blacksquare$ ' Universal' THF may five way to individual products for each OEM $\blacksquare$ Sumps are getting smaller $\blacksquare$ Increased use of hydraulic system vs. mechanical $\blacklozenge$ Additive companies will need to meet many challenges

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.05a
• /
• pp.317-318
• /
• 2012