• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.191-191
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• 2003

쌀에 함유된 지방질은 가공 처리 중 쉽게 가수분해나 산화를 일으켜 이취 또는 불쾌한 맛을 생성하여 밥의 품질을 저하시키는 원인이 된다. 산화를 억제시키기 위해서는 공기와의 접촉을 차단시키는 것이 중요하다. 이러한 목적의 일환으로 본 연구에서는 쌀의 저장기간을 연장시키기 위하여 배아미와 현미를 진공포장한 후 실온에서 보관하면서 14주 동안 2주마다 과산화물가와 산가를 분석하여 산패도를 측정하였다. 비포장 현미와 배아미의 과산화물가는 처음 4주동안은 모두 6∼9 meq/kg정도로 차이가 없었지만, 현미의 경우에는 6주후에는 배아미보다 산패가 빨리 진행되어 휘발성 물질의 생성에 따라 이취미가 나기 시작하였다. 진공포장한 현미와 배아미는 지방질 함량의 차이 때문에 초기에는 과산화물가 0.3 meq/kg정도의 차이가 있었고, 저장과정 중에는 과산화물가의 차이가 거의 없었다. 산가(유리지방산)의 양도 비포장한 배아미와 현미의 경우에는 저장기간중 0.5 mg/g정도의 차이가 있었지만, 진공포장을 한 경우에는 8주 동안에는 큰 차이가 나지 않았으며, 10주후 부터는 0.6 mg/g정도의 차이를 나타냈다. 본 실험으로 배아미와 현미를 진공포장할 경우 비포장하였을 때보다 산패가 억제되어 10주 정도의 저장기간이 연장됨을 확인할 수 있었다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.437-438
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• 2017

본 연구는 독립 운전 모드의 P+MR 기반의 전압제어기의 계통 동기화 방식을 조사한다. 계통 복전 후 계통과의 재연결을 위한 계통 동기화가 고정자 좌표계하에서 제어가 수행되는 경우, 독립운전하에서 정전압, 정주파수를 가지는 교류 지령 전압은 계통 전압으로 대체되는데 이 부분에서 고정자 좌표계 제어하의 현재 출력 전압과 계통 전압의 위상 차이에 기인하여 상당한 전압 오차가 발생할 여지가 있고 이러한 전압 오차 발생은 심각한 전압 과도 상태를 야기할 수 있게 된다. 추가적으로, 인버터의 출력 단에 연결된 부하가 비선형 부하라면 부하에서 생성되는 고조파에 기인하여 위에 언급된 전압 과도 상태가 더욱 심각해질 수 있다. 본 논문에서는 위에 언급된 문제를 해결하기 위한 대책으로 독립 운전 모드하에서의 전압 제어를 위해 사용되는 P+MR 제어 기반의 비선형 부하를 고려한 매끄러운 계통 동기화 방식이 제안되었다. 제안된 매끄러운 계통 동기화 방식은 실험 결과를 통해 검증된다.

• Journal of Korean Port Research
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• v.12 no.1
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• pp.87-93
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• 1998

For the calculation of the free-surface elevation, a new finite difference scheme is studied where the third derivative term for the wave elevation is artificially added in the Eulerian expression of the free-surface boundary condition. The paper presents a comparative analysis with simulations performed by the classical MAC method. More schematic computations are carried out by changing the submergence-depth and angle-of-attack. The present study shows that this new method is very efficient for the simulation of free-surface elevation around the trailing edge.

• Journal of the Society of Disaster Information
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• v.10 no.4
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• pp.583-597
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• 2014

Fire caused by heater has various causes as many as the types of heater. also, lots of damage of human life and property loss are caused, since annually continuous fire accident by heater in traditional market is frequently occurring. There are not many cases of fire due to heater in most of residential facilities such as general house, apartments, etc., because they are supplied with heating boiler, however the restaurant, store and office of the market, sports center, factory, workplace, etc. still use heater, e.g. oilstove, electric heater, etc., so that they are exposed to fire hazard. Also, when investigating the number of fire due to heater, it was analyzed to occur in order of home boiler, charcoal stove, oilstove, gas heater/stove, electric stove/heater, the number of fire per human life damage was analyzed in order of gas heater/stove, oil heater/stove, electric heater/stove, briquette/coal heater. Also, gas and oil related heater were analyzed to have low frequency, however, with high fire intensity. Therefore, this research aimed at considering more scientific fire inspection and identification approach by reenacting and reviewing fire outbreak possibility caused by combustibles' contact and conductivity under the normal condition and abnormal condition in respect of ignition hazard, i.e. minimum ignition temperature, carbonization degree and heat flux along with it, due to oilstove and electric stove, which are still frequently used in public use facility, traditional market, and, of which actual fire occurrence is the most frequent. As the result of reenact test, ignition hazard appeared very small, as long as enough heat storage condition is not made in both test objects(oilstove/electric stove), however carbonization condition was analyzed to be proceeded per each part respectively. Eventually, transition to fire is the ignition due to heat storage, so that it was analyzed to ignite when minimum heat storage temperature condition of fire place is over $500^{\circ}C$. Particularly, in case of quartz pipe, the heating element of electric stove, it is rapidly heated over the temperature of $600^{\circ}C$ within the shortest time(10sec), so that the heat flux of this appears 6.26kW/m2, which was analyzed to result in damage of thermal PVC cable and second-degree burn in human body. Also, the researcher recognized that the temperature change along with Geometric View Factor and Fire Load, which display decrease of heat, are also important variables to be considered, along with distance change besides temperature condition. Therefore, the researcher considers that a manual of careful fire inspection and identification on this is necessary, also, expects that scientific and rational efforts of this research can contribute to establish manual composition and theoretical basis on henceforth fire inspection and identification.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.9
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• pp.939-946
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• 2011

In thermal power generation companies, the recycling of refined ash (LOI < 6%) obtained from a PC-firing furnace is beneficial for the companies, e.g., it can be used for making lightweight aggregates. However, ash having a high LOI, which cannot be reused, is still buried in the ground. To obtain refined ash, the re-burning of high-LOI ash (LOI > 6%) in a PC-firing furnace can be an alternative. In this study, a numerical analysis was performed to demonstrate the effects of ash re-burning. An experimental constant value was decided by TGA (thermo-gravimetric analysis), and a DTF (drop-tube furnace) was used in the experiment for calculating the combustion of ash. On the basis of the trajectory of the moving particles of coal and ash, it was concluded that supplying ash near the burner, which is located high above the ground, is appropriate. On the basis of numerical results, it was concluded that an ash supply rate of 6 ton/h is suitable for combustion, without affecting the PC-firing boiler.

• Journal of the Korean School Mathematics Society
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• v.10 no.3
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• pp.401-413
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• 2007

This study was some part of the main program making better the lessons in the classroom in which those should focus on the creative and self-leading method. The purpose of study was to create the model of Problem Based Learning and investigate its efficiency For the purpose, those researchers tried to reform the Myers' PBL model through the pilot experiment and could get the Model of Korean School PBL appropriate to the our classroom situations. Thirty six students from the enriched class in the junior high school 3rd grades was involved in the experiment for 8 weeks. The results showed that the experimental group had statistically significant difference in the real problem solving test and attitude test. Specially, those students also showed that the ability to translate the variety of problem situations mathematically was so excellent and they also had their own technique to generate the understand of problem solving situations, but they aid not show the significant ability to pose the meaningful problem.

• The Korean Journal of Food And Nutrition
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• v.15 no.3
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• pp.267-271
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• 2002

We have studies in 38 subjects (19 control and 19 experiment) for development of functional food for postpartum body control. Mean age of control and experimental subjects were each other 30.4 and 29.0 years old, and mean body mass index were 20.2 and 21.4. Total weight gain during pregnancy of control and experimental subjects were 14.0kg and 19.8kg. We measured change of weight and liver activity after parturition for 3 months. It shows that weight not reduced until 30 days in postpartum but significantly decreased during 30 days to 90 days. The mean weight of control and experimental subjects were decreased 3.15kg and 6.46kg at 60 days(p<0.05), 4.47kg and 7.44kg at 90 days(p<0.05). In this study, hemoglobin, GOT and CPT level were not changes before and after of experiment, respectively.

• The Korean Journal of Food And Nutrition
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• v.16 no.1
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• pp.54-59
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• 2003

This studies were performed to functional food consisted of herb mixture having an effect on postpartum body weight control in 105 subjects(control group n=54, experimental group n=51). Mean age of control and experimental group were 29.3 and 29.1 Mean pregravida body mass index of control and experimental group were 22.8 and 21.5. Total weight gain during the period of pregnancy of control and experimental group were 19.1kg and 17.8kg. In this studies, changes in postpartum weight was measured until one year after parturition. Until 1 month after parturition, there almost had no changes in weight all of two groups. But after 2 month, change in weight loss between two groups was shown definitely. Mean weight loss of control group and experimental group were 2.3kg and 6.5kg after 2 month, 3.7kg and 9.8kg after 3 month, 5.0kg and 10.4kg after 1 year(p<0.01).

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.3
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• pp.371-377
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• 2007

In this paper, acceleration threshold of perception for the horizontal vibration of tall buildings was estimated. Excessive vibration of tall buildings by wind can give displeasure, such as giddiness and visual insecurity. To provide comfortable environment to residents of tall buildings, acceleration needs to be limited. For tall buildings the first mode of vibration is dominant. To reproduce the first mode of vibration, experiments were performed by generating sine waves by a shaking table. A nitration house was made and forty persons were employed for experiments. The forty persons were organized into five experimental groups, each of which was composed of eight persons, and the threshold of perception for horizontal vibration was measured by increasing acceleration in the range of 0.2Hz through 1.2Hz of frequency, Performance curves were obtained by dividing the distribution of perception for horizontal vibration into the range of $0{\sim}20%,\;21{\sim}40%,\;41{\sim}60%,\;61{\sim}80%\;and\;81{\sim}100%$ and by fitting curves.

• Journal of the Institute of Convergence Signal Processing
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• v.4 no.2
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• pp.12-17
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• 2003

This paper proposes content-based image retrieval system with fuzzy ART neural network algorithm. Retrieving large database of image data, the clustering is essential for fast retrieval. However, it is difficult to cluster huge image data pertinently, Because current retrieval methods using similarities have several problems like low accuracy of retrieving and long retrieval time, a solution is necessary to complement these problems. This paper presents a content-based image retrieval system with neural network in order to reinforce abovementioned problems. The retrieval system using fuzzy ART algorithm normalizes color and texture as feature values of input data between 0 and 1, and then it runs after clustering the input data. The implemental result with 300 image data shows retrieval accuracy of approximately 87%.