• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.2
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• pp.133-142
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• 2023

The large process plant is currently implementing predictive maintenance technology to transition from the traditional Time-Based Maintenance (TBM) approach to the Condition-Based Maintenance (CBM) approach in order to improve equipment maintenance and productivity. The traditional techniques for predictive maintenance involved managing upper/lower thresholds (Set-Point) of equipment signals or identifying anomalies through control charts. Recently, with the development of techniques for big analysis, machine learning-based AAKR (Auto-Associative Kernel Regression) and deep learning-based VAE (Variation Auto-Encoder) techniques are being actively applied for predictive maintenance. However, this predictive maintenance techniques is only effective during steady-state operation of plant equipment, and it is difficult to apply them during start-up and shutdown periods when rises or falls. In addition, unlike processes such as nuclear and thermal power plants, which operate for hundreds of days after a single start-up, because the pumped power plant involves repeated start-ups and shutdowns 4-5 times a day, it is needed the prediction and alarm algorithm suitable for its characteristics. In this study, we aim to propose an approach to apply the optimal predictive alarm algorithm that is suitable for the characteristics of Pumped Storage Power Plant(PSPP) facilities to the system by analyzing the predictive maintenance techniques used in existing nuclear and coal power plants.

• Journal of Biosystems Engineering
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• v.6 no.2
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• pp.48-57
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• 1982

In order to improve the quality of traditionally sun-dried red peppers and to increase the efficiency of drying performance, three types of solar dryers were designed and built, and drying performance of the solar dryers was compared to traditional sun drying. Results obtained from the experiment are summarized as fallows: 1. The air temperature and relative humidity profiles over a 8-hour period measured at the specified locations in the drying chamber of solar dryers appeared to have large variation in each dryer. The rate of drying increased with the temperature rise in the drying chamber of the solar dryer. 2. In general. drying with solar dryers proceeded faster than traditional sun drying. With A'-type of solar dryer developed in the second experiment it was possible to dry red peppers in seven days from an initial moisture content of 80% to safe storage conditions. The drying time with the A'-type solar drier was 50% shorter compared to traditional sun drying. 3. Red peppers appeared to have an increasing or constant-rate drying period until the weight of the product was reduced to about one half the initial weight, followed by a falling-rate drying period. When the dried red peppers were exposed to the atmospere during the night, the moisture content increased as much as 6%, which is much higher than for the grains. 4. It was suggested from the experiment that either a heat storage system or a supplemental heating system in the solar dryer was desirable for more efficient drying operation. 5. It was shown that the solar dryer developed in this study may be suitable for drying other vegetables and fishes, and also offered additional advantages of saving in drying time, maintaining sanitation and minimizing contamination by dust, insects and unfavorable weather condition.

• Journal of the Korean Institute of Rural Architecture
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• v.23 no.4
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• pp.13-20
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• 2021

This study aims to provide necessary, basic data for future space planning of rural housing through a survey on the size of residential space and space utilization of rural housing. To this end, this study analyzed the size and space of rural houses in actual use, and also analyzed the size and characteristics of the essential space for life, which were collected via a survey. In particular, Usan Village in Jangheung, where various types of houses and renewed houses coexist due to continued changes in the form of traditional villages, was selected for a target site of this study. In next step, this study analyzed the current status of use of each house in the village and compared the size of each space and the characteristics of space utilization. The results of the survey on Usan village, on where divergent traditional and modern houses are located, are as follows. First, Usan Village has total 31 traditional and modern houses. Most of the houses have been aging and formed into old-age households, and the expansion, renovation, and construction of farmhouses have progressed. Second, the population of Usan Village has decreased, and the number of residents per household is currently 1.4. Third, the survey indicates that the flat area of rural houses was 80.6m², the average area of living space was 54.1m², and the average area of water storage space was 26.5m², and the main living area was changed to water storage space due to the decrease in the number of household members in rural areas.

• Journal of the Korean Society of Food Science and Nutrition
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• v.11 no.4
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• pp.37-41
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• 1982

In order to determine the optimal condition for making Yugwa (one of the Korean traditional cake) the textures in various conditions were studied by sensory test and texturometer. The changes of texture and fat content in the cake were measured along the period of storage. The results were as follows: (1) The cake were classified in 3 groups according to the leavening agent used in the procedure, namely refined rice wine (W), distilled liquor (L) and yeast group (Y). It was the refined rice wine group that had been 'the best' by sensory test. Its brittleness $(1.40{\pm}0.27)$ was higher than those of L and Y. (2) Crispness measured by bend test prior to soaking into syrup were 1.19, 1.23 and 1.63 in W, L, Y, respectively. (3) Chemical composition (%dry basis)) of Yugwa leavened with W included 9.3 of moisture, 1.3 crude protein, 6.7 crude lipid, 66.4 carbohydrate and 16.3 crude ash. (4) Brittleness decreased gradually along the period of storage while the rancidity increased. From the 40th days of storage, the change of brittleness and rancidity were marked as well as the scores of sensory test decreased significantly. (5) Content of linoleic acid in Yugwa decreased along the period of storage from 52.5% of total fatty acid on the first day to 10.9% on the 50th days Main fatty acids in Yugwa were oleic acid, palmitic acid and stearic acid, all of which were also decreased in content along the period of storage. One remarkable change was the appearance of an unknown fatty acid with 19.54 of retention time, in 50% of total fatty acid, on the 50th day of storage.

• 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.

• Journal of Conservation Science
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• v.30 no.4
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• pp.353-364
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• 2014

Formaldehyde(HCHO) may have a damage effect on Korean traditional textiles, because concentration is high and occurrence frequency is frequent at the exhibition room and storage area. Total 20 specimens were prepared using 4 different materials (silk, cotton, ramie, hemp) after dyeing with 5 colors (undyed, red, yellow, blue, black). The specimens were exposed to HCHO gas in the test chamber. The gas acceleration test was conducted to identify the deterioration of Korean traditional textiles according to HCHO concentration(0.5, 1, 10, 100, 500ppm), to temperature-humidity condition at HCHO 500ppm, and deterioration conditions at HCHO 500ppm. Optical, chemical, and physical evaluation was carried out after the exposure. The results, color difference, grey scale rating, formate($HCO_2{^-}$) of some textiles increased at 500ppm, while pH decreased at 500ppm. Also, color difference, grey scale rating, formate($HCO_2{^-}$) of some textiles increased double damage at high temperatures & humidity, high humidity condition. But, damages of accelerated degradation textiles were slight, because of degradation degree and degradation products. The results suggest that determined the damage to the korean traditional textile, damage level, damage-weighted condition, damage to accelerated degradation textiles. In addition, formaldehyde damaged to yellowing of red textiles, bleaching of accelerated degradation textiles, formic acid damaged to bleaching of total 20 specimens.

• The Korean Journal of Community Living Science
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• v.15 no.3
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• pp.71-84
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• 2004

Recently the globalization of agriculture by the WTO has brought crisis to Korean farmers. Value added agricultural products is the one of the strategies to sustain fanning. The idea for the project traditional fermented soy paste production and distribution was developed by the Gyeonggi-do Agricultural Research Institute. It was necessary to know the purchase condition and consumer needs for production distribution of the soy products. This study aims to investigate the consumers' need analysis of direct-deal soy products and the conditions of a purchase. A questionnaire was administered to 590 subjects living in Gyeonggi-do, Korea. The 107 subjects procured soy paste to buy with the reason of ignorance of preparation (39.2%) and the difficulty of storage and care (31.8%). When selecting the product 95.3%, previous experience (41.1 %) and comparison of each product (34.6%) were major answers, wanted direct-deal purchase from producers if implemented. 142 subjects(24%) experienced direct deal with producers. The main direct route was government and public offices( 42.4 %). The reason for direct purchase was confidence of agricultural products(77.5%). Delivery of 4kg of soy paste and 1.8 L of soy sauce in a glass container (43.0%) was favored twice a year. The kind of soy products for consumers' needs was Doenjang(57.8%) and Gochujang(18.3%). The preferred methods direct-dealing of soy products was direct order(59.9%) after validation, delivery gate to gate (44.2%) and by the internet(4.9%). The results of the study shows that the types of production would have the kinds and quantities diversity with confidence, sanitation, and safety. To regain successful, traditional tastes it is necessary to develop reliable and tasteful products for consumers and develop promotional material.

• Korean Journal of Food Science and Technology
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• v.28 no.1
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• pp.117-121
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• 1996

In order to find the reason for souring of Hansan sogokju (Korean traditional rice wine), microbial distribution, pH change and organic acids were analysed. Besides 161 mM of lactic acid as a major organic acid, small amount of acetic acid, malic acid, propionic acid were found in sogokju. Four different microbial strains were identified from the sogokju. These are two strains of Lactobacillus spp., Bacillus sp. and yeast. The pH of sogokju was changed from 4.01 to 3.29 during 18 days storage at $30^{\circ}C$. Amount of total acidity increased from 9 to 34.86 at the same condition. Notable change in the soured sogokju was an increase of the lactic acid (from 161 mM to 192 mM). So, we could assume that it was soured by an additional production of lactic acid by lactic acid bacteria during storage. The shelf life of sogokju was 41 days below $15^{\circ}C$ degree because this temperature was hard condition for the growth of Lactobacillus spp., causative bacteria responsible for additional lactic acid production.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1348-1357
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• 2015

Under traditional unified power quality conditioner (UPQC) control, a UPQC series converter (SC) is mainly used to handle grid-side power quality problems while its parallel converter (PC) is mainly used to handle load-side power quality problems. The SC and PC are relatively independent. The SC is usually in standby mode and it only runs when the grid voltage abruptly changes. In this paper, novel UPQC coordinated control strategies are proposed which use the SC to share the reactive power compensation function of the PC especially without grid-side power quality problems. However, in some cases, there will be a circulating current between the SC and the PC, which will probably influence the compensation fashion, the compensation capacity, or the normal work of the UPQC. Through an active power circulation analysis, strategies with and without a circulating current are presented which fuses the reactive power allocation strategy of the SC and the PC, the composite control strategy of the SC and the compensation strategy of the DC storage unit. Both of the strategies effectively solve the SC long term idle problem, limit the influence of the circulating current, optimize all of the UPQC units and reduce the production cost. An analysis, along with simulation andexperimental results, is presented to verify the feasibility and effectiveness of the proposed control strategies.

• Journal of the Korean Home Economics Association
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• v.20 no.1
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• pp.79-85
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• 1982

The objective of this study is to apply the modular furniture system, which has been developed actively in western Europe and America since 1970's, to Korean contemporary furniture having converted into western style gradually. The factors requiring the modular furniture system in today's residential environment are as follows; 1. Population increase and urbanization 2. Development of industrial technology 3. Improvement of living condition and change of life style. As these factors increase the problem of diminishing space, multiple functional modular furniture concept has become a solution. Reviewing the current scene of the western modular furniture system, it is classified into modular seating system, mopular wall system, modular commode system and modular storage system. Korean wardrobe, which is am mixed style of traditional and contemporary furniture, should change to a closet eventually because of the grand size and unpractical use of space. Since most Korean family, however, have wardrobes already, it will be necessary to have a turning period to systemized the closet space in Korean residential interior. For the turning period, application of the modular wall system would be one answer to substitute the wardrobe.