• Journal of the Korean Wood Science and Technology
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• v.17 no.1
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• pp.3-11
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• 1989

This study was carried out to investigate the physical and mechanical properties. durability of adhesive bond and paint film for the basic data which were required to determine the suitability as a raw material for furniture the laminated veneer lumber (LVL) with pitch pine (Pinus rigida Mill). The results obtained were as follows; 1) The proper pressing time for making the LVL was over 45 second per milimeter of LVL thickness. 2) The bending strength of the LVL was lower than that of the solid wood but the compressive strength of the LVL was similar to that of the solid wood. The strength increased with the decrease of veneer thickness. 3) The impact bending absorbed energy of the LVL was 0 to 0.3 kg.m/$cm^2$ in the direction of parallel to the grain. The energy of the LVL was lower than that of the solid wood (0.68 kg.m/$cm^2$). 4) In warm water soaking and cold-dry tests, delamination of adhered layers surface crack, swelling, and color change were not found when the hot pressing time was over 45 second per milimeter of LVL thickness. As a result of soak under vacuum test shrinkage in the direction of parallel to the grain was about -1.0 percent and. was about 3.0 percent in the direction of the perpendicular to the grain. 6) The film cacks on the LVL's surface after the wet and cold-dry test were not found at all. 7) In the use of the LVL for interior decoration it was considered that the surface of the LVL be overlaid crossly with fancy veneers of birch and paulownia, etc. This cross overlayirg methods have resulted in few cracks on the fancy veneer.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.1
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• pp.35-45
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• 2018

Image data collected by an airborne hyperspectral camera system have a great usability in coastal line mapping, detection of facilities composed of specific materials, detailed land use analysis, change monitoring and so forh in a complex coastal area because the system provides almost complete spectral and spatial information for each image pixel of tens to hundreds of spectral bands. A few approaches after classifying by a few approaches based on SAM(Spectral Angle Mapper) supervised classification were applied for extracting optimal land cover information from hyperspectral images acquired by CASI-1500 airborne hyperspectral camera on the object of a coastal area which includes both land and sea water areas. We applied three different approaches, that is to say firstly the classification approach of combined land and sea areas, secondly the reclassification approach after decompostion of land and sea areas from classification result of combined land and sea areas, and thirdly the land area-only classification approach using atmospheric correction images and compared classification results and accuracies. Land cover classification was conducted respectively by selecting not only four band images with the same wavelength range as IKONOS, QuickBird, KOMPSAT and GeoEye satelllite images but also eight band images with the same wavelength range as WorldView-2 from 48 band hyperspectral images and then compared with the classification result conducted with all of 48 band images. As a result, the reclassification approach after decompostion of land and sea areas from classification result of combined land and sea areas is more effective than classification approach of combined land and sea areas. It is showed the bigger the number of bands, the higher accuracy and reliability in the reclassification approach referred above. The results of higher spectral resolution showed asphalt or concrete roads was able to be classified more accurately.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.104-109
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• 2014

Purpose: Conventional pinhole scintigraphy offers a high resolution and generally use for thyroid scan or bone scintigraphy. the aim of this study is to evaluate performance of each aperture according to the diameter size. Materials and Methods: In this study 2 mm, 4 mm, 6 mm, 8 mm diameter pinhole collimators were mounted on Siemens E.CAM systems. In order to evaluate performance evaluation of each aperture, we acquired projection image by using SPECT for evaluating FWHM, resolution test and static image for evaluating thyroid phantom test. Results: As a result of FWHM showed 2.2 mm FWHM, 3.2 mm FWHM, 5.4 mm FWHM, 7.5 mm FWHM per each aperture in the resolution test. SNR, uniformity, contrast were acquired result from thyroid phantom test comparing general image and delayed image. as a result of SNR showed 6.55, 8.47, 6.2, 5.23 in case of general image and 5.25, 5.01, 5.38, 5.82 in case of delayed image per each aperture. as a result of uniformity showed 0.152, 0.118, 0.161, 0.19 in case of general image and 0.19, 0.199, 0.185, 0.171 in case of delayed image per each aperture. as a result of contrast showed 1.31, 1.19, 1.15, 1.01 in case of general image and 1.09, 1.08, 1.04, 1 in case of delayed image per each aperture. Conclusion: Resolution and sensitivity were heavily influenced by aperture size. and also we found advantage of delayed image as a result of thyroid phantom test.

• Journal of Radiation Protection and Research
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• v.35 no.1
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• pp.34-42
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• 2010

With the expanded use of radiation in modern medical practices, the most important issue in regards to efforts to reduce individual exposure dose is quality assurance. Therefore in order to study the present condition of quality assurance, the Gwangju Metropolitan City area was divided into five districts each containing ten hospitals. Four experiments were conducted: a reproducibility experiment for kVp, mA, and examination time (sec) intensity of illumination; half-value layer (HVL) measurement; and beam perpendicularity test matching experiment. The tube voltage reproducibility experiment for all fifty hospitals resulted in a 95.33% passing rate and mA and examination time both resulted in a 77.0% passing rate. The passing rate for intensity of illumination was 86.0% and 52.0% for HVL, which was the lowest passing rate of all four factors. For the beam perpendicularity test matching experiment, generally the central flux is matched to within $1.5^{\circ}$. Of all fifty hospitals 30.0% were beyond $3^{\circ}$. The results of the survey showed that 58% responded that they knew about quality assurance cycle. All fifty respondents stated that they have not received any training in regards to quality assurance at their current place of employment. Although quality assurance is making relative progress, the most urgent issue is awareness of the importance of quality assurance. Therefore, the implementation of professional training focusing on safety management and accurate quality assurance of radiation will reduce the exposure to radiation for radiologists and patients and higher quality imaging using less dosage will also be possible.

• Food Science and Preservation
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• v.21 no.4
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• pp.536-543
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• 2014

In this study, we examined the quality characteristics of oriental melon concentrate according to its content in the production of Makgeolli using uncooked rice. The results show that when more oriental melon concentrate was added to the Makgeolli and as the fermentation progressed, the sugar content of the Makgeolli increased. A slight increase was noted in all samples. The total acidity from the second day of fermentation did not show a significant difference according to the addition of 0.77~0.85% oriental melon concentrate. The pH of Makgeolli was slightly higher. The addition of more oriental melon concentrate after its decrease on the first day showed no significant difference in the pH. Reducing sugars in the Makgeolli slightly increase on the second day, after it rapidly decreased on the first day. The alcohol content increased as the fermentation progressed, and the Makgeolli with 9% (v/w) oriental melon concentrate added on the fourth day of its fermentation showed the highest alcohol content of 11.15%. Thus, it verified that as more oriental melon concentrate is added, the higher the alcohol content becomes. The acetaldehyde content of the alcoholic ingredients was low. The addition of and the increase in the oriental melon concentrate and the methanol were highest in the Makgeolli when 6% (v/w) oriental melon concentrate(199.08 ppm) was added. For the sensory characteristics, the Makgeolli with 6% (v/w) oriental melon concentrate showed the highest color, odor, taste and overall values of 3.60, 3.60, 2.80 and 3.60, respectively; but in general, it showed low values. The result showed that during the production of Makgeolli, oriental melon concentrate can be added, but a study on the use of a sweetener to improve the quality of the Makgeolli is desirable.

• Journal of Korea Game Society
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• v.4 no.3
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• pp.11-20
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• 2004

Virtual reality that we have seen from the movies in 80's and 90's is hawing near based on the rapid progress of science together with a computer technology. Various virtual reality system developments (such as VRML, HMD FishTank, Wall Type, CAVE Type, and so on) and the advancement of those systems make for the embodiment of virtual reality that gives more sense of the real. Virtual reality is so immersive that makes people feel like they are in that environment and enable them to manipulate without experiencing the environment at first hand that is hard to experience in reality. Virtual reality can be applied to the spheres, such as education, high-level programming, remote control, surface exploration of the remote satellite, analysis of exploration data, scientific visualization, and so on. For some connote examples, there are training of a tank and an aeroplane operation, fumiture layout design, surgical operation practice, game, and so on. In these virtual reality systems, the actual operation of the human participant and virtual workspace are connected each other to the hardware that stimulates the five senses adequately to lend the sense of the immersion. There are still long way to go, however, before long it will be possible to have the same feeling in the virtual reality as human being can have by further study and effort. In this thesis, the basic definition, the general idea, and the kind of virtual reality were discussed. Especially, CAVE typed in reality that is highly immersive was analyzed in definition, and then the method of VR programming and modeling in the virtual reality system were suggested by showing the restoration process of Kyongbok Palace (as the content of the original form of the culture) that was made by KISTI(Korea Institute of Science and Technology Information) in 2003 through design process in virtual reality system. Through these processes, utilization of the immersive virtual reality system was discussed and how to take advantage of this CAVE typed virtual reality system at the moment was studied. In closing the problems that had been exposed in the process of the restoration of the cultural property were described and the utilization plan of the virtual reality system was suggested.

• Fire Science and Engineering
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• v.31 no.5
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• pp.53-62
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• 2017

Electric power which is the energy source of economy and industries requires long distance transportation due to regional difference between its production and consumption, and it is supplied through the multi-loop transmission and distribution system. Prior to its actual use, electric power flows through several transformations by voltage transformers in substations depending on the characteristics of each usage, and a transformer has the structure consisting of the main body, winding wire, insulating oil and bushings. A transformer fire that breaks out in substations entails the primary damage that interrupts the power supply to houses and commercial facilities and causes various safety accidents as well as the secondary economic losses. It is considered that causes of such fire include the leak of insulating oil resulting from the destruction of bottom part of bushings, and the chain reaction of fire due to insulating oil that reaches its ignition point within 1 second. The smoke detector and automatic fire extinguishing system are established in order to minimize fire damage, but a difficulty in securing golden time for extinguishing fire due to delay in the operation of detector and release of gas from the extinguishing system has become a problem. Accordingly, this study was carried out according to needs of active mechanism to prevent the spread of fire and block the leak of insulating oil, in accordance with the importance of securing golden time in extinguishing a fire in its early stage. A bushings fireproof structure was developed by applying the high temperature shape retention materials, which are expanded by flame, and mechanical flame cutoff devices. The bushings fireproof structure was installed on the transformer model produced by applying the actual standards of bushings and flange, and the full scale fire test was carried out. It was confirmed that the bushings fireproof structure operated at accurate position and height within 3 seconds from the flame initiation. It is considered that it could block the spread of flame effectively in the event of actual transformer fire.

• Journal of Energy Engineering
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• v.28 no.3
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• pp.65-79
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• 2019

The study attempted to estimate the optimal facility capacity by combining renewable energy sources that can be connected with gas CHP in industrial complexes. In particular, we reviewed industrial complexes subject to energy use plan from 2013 to 2016. Although the regional designation was excluded, Sejong industrial complex, which has a fuel usage of 38 thousand TOE annually and a high heat density of $92.6Gcal/km^2{\cdot}h$, was selected for research. And we analyzed the optimal operation model of CHP Hybrid System linking fuel cell and photovoltaic power generation using HOMER Pro, a renewable energy hybrid system economic analysis program. In addition, in order to improve the reliability of the research by analyzing not only the heat demand but also the heat demand patterns for the dominant sectors in the thermal energy, the main supply energy source of CHP, the economic benefits were added to compare the relative benefits. As a result, the total indirect heat demand of Sejong industrial complex under construction was 378,282 Gcal per year, of which paper industry accounted for 77.7%, which is 293,754 Gcal per year. For the entire industrial complex indirect heat demand, a single CHP has an optimal capacity of 30,000 kW. In this case, CHP shares 275,707 Gcal and 72.8% of heat production, while peak load boiler PLB shares 103,240 Gcal and 27.2%. In the CHP, fuel cell, and photovoltaic combinations, the optimum capacity is 30,000 kW, 5,000 kW, and 1,980 kW, respectively. At this time, CHP shared 275,940 Gcal, 72.8%, fuel cell 12,390 Gcal, 3.3%, and PLB 90,620 Gcal, 23.9%. The CHP capacity was not reduced because an uneconomical alternative was found that required excessive operation of the PLB for insufficient heat production resulting from the CHP capacity reduction. On the other hand, in terms of indirect heat demand for the paper industry, which is the dominant industry, the optimal capacity of CHP, fuel cell, and photovoltaic combination is 25,000 kW, 5,000 kW, and 2,000 kW. The heat production was analyzed to be CHP 225,053 Gcal, 76.5%, fuel cell 11,215 Gcal, 3.8%, PLB 58,012 Gcal, 19.7%. However, the economic analysis results of the current electricity market and gas market confirm that the return on investment is impossible. However, we confirmed that the CHP Hybrid System, which combines CHP, fuel cell, and solar power, can improve management conditions of about KRW 9.3 billion annually for a single CHP system.

• Journal of the Korean Society of International Agriculture
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• v.30 no.4
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• pp.313-319
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• 2018

The purpose of this study was to provide the basis for the vegetable seedlings export research and policy establishment by analyzing vegetable seedlings export status from the agricultural quarantine statistics in Korea and the changes of temperature and relative humidity during the vegetable seedlings shipping export transportation to Japan. From 2007 to 2016, various vegetable seedlings such as cabbage, tomatoes, cucumber, onion and etc., have been exported to more than 20 countries around the world. The main exporting country of vegetable seedlings for commercial purposes is Japan, and the major exported seedlings to Japan in 2016 were fruit vegetable grafted seedlings such as eggplant, tomato, cucumber, watermelon and pepper. Total export amount of the fruit vegetable seedlings to Japan in 2016 were 2,575,446 seedlings and it is approximately 0.7 to 1.6 million dollars. The grafted seedlings exported to Japan were consumed for urban agriculture and farm use. Shipping transportation took about 24 hours in the process of receiving the package ${\rightarrow}$ shipment ${\rightarrow}$ quarantine (Busan port) ${\rightarrow}$ Quarantine (Japan Shimonoseki Port). The growing demand for vegetable seedlings due to the development of urban agriculture in Japan and the growing interest and demand for vegetable grafting seedlings in neighboring countries such as Russia will be an opportunity to expand the export size of Korean vegetable grafting seedlings. In order to expand the export of vegetable seedlings in Korea, it is necessary to ensure further active government policy and research on the production of export seedlings, seedlings storage and transportation technology and analysis of exporting countries' market information.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.1
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• pp.64-68
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• 2019

Purpose In the preparation process for N-13 Ammonia injections, there were radioactive medicines adsorbed on filters remarkably. Hereby, we have compared the adsorption rate and quality test on Millex GS filter and Satorious Minisart filter, both representatively hydrophilic sterilizing filters, also evaluated which filter is more accommodative for N-13 Ammonia injection. Materials and Methods The filters used for sterilization of N-13 Ammonia injections were Millex GS filter($0.22{\mu}m$) mand Satorious Minisart filter ($0.2{\mu}m$), which are generally used to strain aqueous solutions. After the N-13 Ammonia passes through each sterilization filter, the adsorption rate of the filter (n=10) is determined by measuring not only the radioactivity through the filter also the amount of radioactivity remaining in it using a Dose Calibrator. The N-13 Ammonia injections after each filter is tested by the quality control test to conform to the Samsung Medical Center standard. Results The ratio of radioactivity passed through Millex GS indicated $29.0{\pm}17.6%$. Satorious Minisart filters output was $80.9{\pm}3.2%$, respectively. Each ratio of radioactivity adsorbed on the sterile filter was $71.0{\pm}17.6%$ for Millex GS and $19.1{\pm}3.2%$ for the Satorious Minisart filters, respectively. Furthermore, on the ratio of filtered radioactivity, Using Satorious Minisart filter showed about 2.8 times higher than using Millex GS filter. The quality testing of N-13 Ammonia injections through each filter met the Samsung Medical Center standard. Conclusion The Millex GS filter is composed of cellulose acetate and cellulose nitrate, whereas the Satorious Minisart filter if composed only of cellulose acetate. Therefore, the presence of cellulose nitrate in the membrane seems to have made differences. Therefore, the use of Satorious Minisart filter in the preparation of N-13 Ammonia injection solution minimized the loss of radioactive medicines due to filter adsorption, thereby improving the synthesis yield.