• IE interfaces
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• v.12 no.2
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• pp.193-204
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• 1999

Development of high technology especially in telecommunication and precise weapon systems will impact the future battle field environment. So it is not difficult to anticipate the environment of military command and control system will be changed rapidly. Considering these future battle field environment, military needs automated C4I (Command, Control, Communication, Computer and Intelligence) system, namely real time decision support system which is combined high technologies. Most of advanced countries have been studied and developed these kinds of systems and already applied these systems in real military operations. In order to take a military initiative in Korea peninsula it is essential to catch up with this trend and procure C4I system. The purpose of this research is to present the method and the direction of optimal C4I system development model. First we survey the related theory about C4I systems. Second we present the conceptual framework for C4I system concept development. Third we model the system using Timed Petri-Net and perform simulation. Finally we analyze the through-put time and suggest alternatives. If we model using the real organization structure, operational tasks and various situations then optimal C4I system would be developed.

• Applied Biological Chemistry
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• v.39 no.1
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• pp.44-48
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• 1996

Effects of storage temperature on the retrogradation of 50% nonwaxy rice flour gels stored at $20^{\circ}C,\;4^{\circ}C\;and\;-18^{\circ}C$ for 6 days were investigated by ${\alpha}-amylase-iodine$ method, differential scanning calorimetry(DSC) and x-ray diffractometry. The retrogradation of gels increased with increasing storage time and the initial retrogradation rate was higher. The degree of retrogradation gels stored at different temperature increased as following order, $-18^{\circ}C>20^{\circ}C>4^{\circ}C$. The enthalpy of retrograded rice flour by DSC showed similar as the degree of retrogradation by ${\alpha}-amylase-iodine$ method, but the differences between storage temperatures were clear in using ${\alpha}-amylase-iodine$ method. X-ray diffraction patterns of gels stored at $4^{\circ}C\;and\;20^{\circ}C$ showed small peaks at $2{\theta}=17^{\circ}\;and\;20^{\circ}$, but the difference was not detected.

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.578-582
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• 2010

$ZrB_2$ has a melting point of $3245^{\circ}C$ and a relatively low density of $6.1\;g/cm^3$, which makes this a candidate for application to ultrahigh temperature environments over $2000^{\circ}C$. Beside these properties, $ZrB_2$ is known to have excellent resistance to thermal shock and oxidation compared with other non-oxide engineering ceramics. In order to enhance such oxidation resistance, SiC was frequently added to $ZrB_2$-based systems. Due to nonsinterability of $ZrB_2$-based ceramics, research on the sintering aids such as $B_4C$ or $MoSi_2$ becomes popular recently. In this study, densification and high-temperature properties of $ZrB_2$-SiC ceramics especially with $B_4C$ are investigated. $ZrB_2$-20 vol% SiC system was selected as a basic composition and $B_4C$ or C was added to this system in some extents. Mixed powders were sintered using hot pressing (HP). With sintered bodies, densification behavior and high-temperature (up to $1400^{\circ}C$) properties such as flexural strength, hardness, and so on were examined.

• Bulletin of the Korean Chemical Society
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• v.20 no.4
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• pp.403-404
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• 1999

• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.11-19
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• 2019

The properties of microalgae as bioresources for biodiesel production can be improved by adding nitrogen sources into the culture medium. Thus, Nannochloropsis oceanica CCAP 849/10 was cultured in f/2 media supplemented with five different forms of nitrogen at $0.88mmol-N\;l^{-1}$ each: ammonium bicarbonate ($NH_4HCO_3$), ammonium sulfate ($(NH_4)_2SO_4$), sodium nitrate ($NaNO_3$), ammonium nitrate ($NH_4NO_3$), and urea. The cell density, lipid content, and fatty acid profile of the microalga were determined after 15 days of cultivation. The growth of N. oceanica based on cell number was lowest in the medium with $NH_4NO_3$, and increased significantly in the medium with $NH_4HCO_3$. Cells treated with $(NH_4)_2SO_4$, and $NH_4NO_3$ produced the highest total lipid contents (i.e., 65% and 62% by dry weight, respectively). The fatty acid profiles of the microalga were significantly different in the various nitrogen sources. The major fatty acids detected in cultures supplemented with $NH_4HCO_3$, $(NH_4)_2SO_4$, $NH_4NO_3$, or urea were C14:0, C16:0, C16:1, C18:0, C18:1, C18:2, C20:5, and C22:6. However, the C16:1 content in the $NaNO_3$-supplemented culture was very low. This study highlights that the nitrogen source can strongly influence lipid production in N. oceanica and its fatty acid composition.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.7
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• pp.1115-1119
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• 2007

This study was conducted to determine the difference between satellite cells (porcine) and myoblasts (C2C12) in their differentiation under the influence of 2, 4-thiazolidindion. C2C12 myoblast cells and porcine satellite cells (isolated from 10 d old $Landrace{\times}Duroc$ piglets) were grown to absolute confluency. Post confluent cells (day 0) were further exposed to adipogenic induction medium along with 2, 4-thiazolidindion ($8{\mu}M$) for 2 d. Thereafter, cells were exposed to 2, 4-thiazolidindion alone every 2 d till day 10 and analysed. The control was cultured in differentiation medium without any treatment. Increased (p<0.05) expression of transcriptional factors i.e. C/EBP-${\alpha}$ and PPAR-${\gamma}$ and transition of cells to adipocyte morphology was noticed from 2 d and 4 d onwards in satellite cells (Porcine) and myoblasts (C2C12) respectively. Myogenesis was observed to be suppressed completely in case of satellite cells compared to myoblasts in response to 2, 4-thiazolidindion. Pax-7 (transcriptional factor) appeared as a sole entity to satellite cells only, as it was not identified in case of myoblasts. Although both the cells were converting to adipoblasts, the degree of their conversion was different in response to 2, 4-thiazolidindion. Therefore, the hypothesis that satellite cells contribute various domains to the growing myoblasts appeared obscured and found to be dependent on the proliferative energy/or degree of fusion. However, it revealed satellite cells as currency to myoblasts/muscle.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.6
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• pp.994-998
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• 2002

The effect of heat-shock treatment of soybean on the quality characteristics of soybean sprouts was investigated. Six groups of soybeans were heat-treated in 35, 40, 45$^{\circ}C$ for 60 and 120 min respectively and then cultivated by a standard method to measure growth parameters, rot ratio, color, vitamin C content and sensory characteristics. Soybean sprouts of 4$0^{\circ}C$/120 min treatment showed the higher weight, while 4$0^{\circ}C$/60 min sample showed thicker hypocotyl and longer cotyledon than the control. In both rot ratio and viable cell count, the lowest values were obtained in soybean sprouts of control and also in 4$0^{\circ}C$/60 min treated samples, while other heat-treated samples showed higher rot ratio and cell counts than the control. Heat treatment of soybean increased the lightness and decreased the yellowness of cotyledon of sprouts. Vitamin C contents of sprouts were increased by heat treatment. Sensory test showed that the heat treatment reduced benny odor and bitter taste but enhanced the nutty taste. Soybean sprouts of 4$0^{\circ}C$/60 min resulted in significantly higher scores in overall appearance and palatability than other samples.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.4
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• pp.206-214
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• 2001

Cooling rate shows the highest as about 0.7$^{\circ}C$/hr on spring season and the lowest as about 0.3$^{\circ}C$/hr on september at plain place. The correlation coefficient between net radiation and cooling rate from sunrise to sunset was 0.63$^{**}$, It became higher to 0.90$^{**}$ when the wind speed decreased lower than 0.5 m/sec, and it decreased as the wind speed increased. On a clear and calm day, cooling rates were observed as 1.4$^{\circ}C$/hr on the plain (site 1, 2, 3), 1.2$^{\circ}C$/hr on the slope (site 4, 5) and 0.6$^{\circ}C$/hr on the top of mountain (site 6). In condition of the wind speed is 1.2~2 m/sec on a clear and calm day and the temperature on the top of mountain is lower than that of slope and plain, the temperature on the slope (site 4,5) was increased unlike our expectation.ion.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.339-349
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• 1999

The dental structure substituted by restorative materials may produce discomfort resulting from hot or cold stimuli. To investigate the effects of this stimuli on the human teeth, thermal analysis was carried out by calculation of general heat conduction equation in a modeled tooth using numerical method. The method has been applied to axisymmetric and two-dimensional model, analyzing the effects of constant temperature $4^{\circ}C\;and\;60^{\circ}C$. That thermal shock was provided for 2 seconds and 4 seconds, respectively and recovered to normal condition of $20^{\circ}C$ until 10 seconds. The thermal behavior of tooth covered with a crown of gold or stainless steel was compared with that of tooth without crown. At the same time, the effects of restorative materials(amalgam, gold and zinc oxide-eugenol(ZOE)) on the temperature of PDJ(pulpo-dentinal junction) has been studied. The geometry used for thermal analysis so far has been limited to two-dimensional as well as axisymmetric tooth models. But the general restorative tooth forms a cross shaped cavity which is no longer two-dimensional and axisymmetric. Therefore, in this study, the three-dimensional model was developed to investigate the effect of shape and size of cavity. This three-dimensional model might be used for further research to investigate the effects of restorative materials and cavity design on the thermal behavior of the real shaped tooth. The results were as follows; 1. When cold temperature of $4^{\circ}C$ was applied to the surface of the restored teeth with amalgam for 2 seconds and recovered to ambient temperature of $20^{\circ}C$, the PDJ temperature decreased rapidly to $29^{\circ}C$ until 3 seconds and reached to $25^{\circ}C$ after 9 seconds. This temperature decreased rather slowly with stainless steel crown, but kept similar temperature within $1^{\circ}C$ differences. Using the gold as a restorative material, the PDJ temperature decreased very fast due to the high thermal conductivity and reached near to $25^{\circ}C$ but the temperature after 9 seconds was similar to that in the teeth without crown. The effects of coldness could be attenuated with the ZOE situated under the cavity. The low thermal conductivity caused a delay in temperature decrease and keeps $4^{\circ}C$ higher than the temperature of other conditions after 9 seconds. 2. The elapse time of cold stimuli was increased also until 4 seconds and recovered to $20^{\circ}C$ after 4 seconds to 9 seconds. The temperature after 9 seconds was about $2-3^{\circ}C$ lower than the temperature of 2 seconds stimuli, but in case of gold restoration, the high thermal conductivity of gold caused the minimum temperature of $21^{\circ}C$ after 5 seconds and got warm to $23^{\circ}C$ after 9 seconds. 3. The effects of hot stimuli was also investigated with the temperature of $60^{\circ}C$. For 2 seconds stimuli, the temperature increased to $40^{\circ}C$ from the initial temperature of $35^{\circ}C$ after 3 seconds of stimuli and decreased to $30^{\circ}C$ after 9 seconds in the teeth without crown. This temperature was sensitive to surface temperature in the teeth with gold restoration. It increased rapidly to $41^{\circ}C$ from the initial temperature of $35^{\circ}C$ after 2 seconds and decreased to $28^{\circ}C$ after 9 seconds, which showed $13^{\circ}C$ temperature variations for 9 seconds upon the surface temperature. This temperature variations were only in the range of $5^{\circ}C$ by using ZOE in the bottom of cavity and showed maximum temperature of $37^{\circ}C$ after 3 seconds of stimuli.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.12
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• pp.1832-1838
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• 2010

The objective of this study was to improve the flavor of Cheonggukjang prepared by the culture optimization of starter with the fibrinolytic activity. After 25 strains isolated from the commercial Cheonggukjang and Doenjang in different regions were compared, 7 Bacillus strains with proteolytic and slime-producing activities were selected. When the fibrin plate method for fibrinolytic activity was applied, CJJN-4 and 5 showed the higher activity in tripticase soy broth (TSB). All Cheonggukjang prepared with CJJN-4 and 5 also had the fibrinolytic activity, regardless of culture temperature or time. Especially, Cheonggukjang prepared at $40^{\circ}C$ showed higher activity than $45^{\circ}C$, and Cheonggukjang prepared with CJJN-4 for 48 hr at $40^{\circ}C$ showed the highest fibrinolytic activity. Although there was no significant difference in pH of Cheonggukjang prepared with CJJN-4 or 5 during 72 hr at $40^{\circ}C$, Cheonggukjang prepared with CJJN-4 at $45^{\circ}C$ had lower pH until 60 hr than $40^{\circ}C$ or CJJN-5. The total amino type nitrogen contents of Cheonggukjang were 1,139.6 (CJJN-4) and 1,027.6 mg% (CJJN-5) for 72 hr at $40^{\circ}C$, and their producing rates were also higher at $40^{\circ}C$ fermentation than $45^{\circ}C$. Meanwhile, the contents of ammonia type nitrogen induced unpleasant flavor were lower in Cheonggukjang with CJJN-4 and 5 at $40^{\circ}C$ than CJJN-5 at $45^{\circ}C$. Therefore, Cheonggukjang fermented with CJJN-4 starter at $40^{\circ}C$ had the improved flavor, such as change of amino or ammonia type nitrogen production, and higher fibrinolytic activity.