• Journal of KSNVE
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• v.9 no.2
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• pp.265-272
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• 1999

A LMS algorithms has been widely used for an adaptive filter algorithm in active noise control systems. But this algorithm has poor convergence and it is very difficult to select optimal convergence parameters in this algorithm. In this paper, a fuzzy LMS algorithm where the convergence parameters are computed using a fuzzy logic controller was proposed. A proposed algorithm was applied to active noise control system in HVAC(central Heating Ventilation and Air Conditioning) ducts. The experimental ducts and experimental apparatus were designed and manufactured for experiments, and the modelling of the experimental ducts was also performed for computer simulations. Computer simulations and experiments were performed to show the effectiveness of a proposed algorithm.

• Journal of the Korean Institute of Rural Architecture
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• v.18 no.2
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• pp.29-37
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• 2016

This study is aimed to suggesting a hypothesis about the process of improvement of houses of the Korean-Chinese, comparing how Han Chinese and Korean-Chinese houses changed in Yanbian Area of China. This draws the conclusion by analyzing the field survey about residence of the Han Chinese and the Korean-Chinese in Yanbian Area of China. First of all, the characteristic of residence style change and the plan of rural houses of the Han Chinese are in the following. The plan of houses has been changed from allocating rooms from side to side with the kitchen as the center to linking each functional spaces through the aisle. And the main bedroom of houses becomes the central space for family members instead of Kang (partial Ondol) by expanding the floor heating system under the whole floor in houses. Next, the feature of residence style changes of the Han Chinese and the Korean-Chinese is as follows. In 1970s barns disappeared from houses of the Korean Chinese, but houses of the Han Chinese were not much changed. From 1980s to 1990s, spaces linking each rooms with aisles had appeared for comfortableness of residence and respecting each individual's privacy. On the other hand, The houses of the Korean-Chinese make a whole big space by getting rid of walls between the rooms. And after 2 thousand years later, Han Chinese houses have a bedroom with floor heating system. Both houses of the Korean-Chinese and the Han Chinese are changed to have a residence style which taking sedentary style and standing style.

• Atmosphere
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• v.20 no.3
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• pp.333-341
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• 2010

The stratiform rain fraction is investigated in the tropical boreal winter Madden-Julian oscillation (MJO) and summer intraseasonal oscillation (ISO) using Tropical Rainfall Measuring Mission (TRMM) Precipitation Rader data for the 11-yr period from 1998 to 2008. Composite analysis shows that the MJO/ISO produces larger stratiform rain rate than convective rain rate for nearly all phases following the propagating MJO/ISO deep clouds, with the greatest stratiform rainfall amount when the MJO/ISO center is located over the central-eastern Indian Ocean and the western Pacific. The fraction of the intraseasonally filtered stratiform rainfall compared to total rainfall (i.e., convective plus stratiform rainfall) amounts to 53~56%, which is 13~16% larger than the stratiform rain fraction estimated for the same data on seasonal-to-annual time scales by Schumacher and Houze. This indicates that the MJO/ISO exhibits the organized rainfall process which is characterized by the shallow convection/heating at the incipient phase and the subsequent flare-up of strong deep convection, followed by the development of stratiform clouds at the upper troposphere.

• Geomechanics and Engineering
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• v.33 no.1
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• pp.65-75
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• 2023

Recycled concrete aggregate (RCA) is widely used as a construction material in road construction, concrete structures, embankments, etc. However, it has been reported that calcite (CaCO₃) precipitation from RCA can be a cause of clogging when used in drainage applications. An accelerated calcite precipitation (ACP) procedure has been devised to evaluate the long-term geochemical performance of RCA in subsurface drainage systems. While the ACP procedure was useful for the French Drain application, there remained opportunities for improvement. In this study, key factors that control the formation of calcite precipitation were quantitatively evaluated, and the results were used to improve the current prototype ACP method. A laboratory parametric study was carried out by investigating the effects of reaction temperature and time on the formation of calcite precipitation of RCA, with determining an optimum reaction temperature and time which maximizes calcite precipitation. The improved ACP procedure was then applied to RCA samples that were graded for Type I Underdrain application, to compare the calcite precipitation. Two key findings are (1) that calcite precipitation can be maximized with the optimum heating temperature (75℃) and time (17 hours), and (2) the potential for calcite precipitation from RCA is not as significant as for limestone. With the improved ACP procedure, the total amount of calcite precipitation from RCAs within the life cycle of a drain system can be determined when RCAs from different sources are used as pipe backfill materials in a drain system.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.1
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• pp.8-16
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• 2023

In this work, we report basic performance test results of a lab-scale three phase alternative current (AC) arc plasma torch system for plasma gas reforming applications. The suggested system primarily consists of three graphite electrodes inclined at 12.5° to the central axis, a 𝞥 150 mm cylindrical gas path and a three phase-60 Hz AC power supply. At air flow rate of 50 Lpm and arc currents of 100-175 A, test results revealed that plasma resistances were decreasing from 1.08 Ω to 0.53 Ω with the increase of plasma power from 9.3 kW to 13.8 kW, causing the decrease of power factor and increase of the line voltages. However, the injected air can be heated quickly up to the temperatures of >1,200℃ when injecting AC arc plasma powers of >10 kW.

• Radiation Oncology Journal
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• v.9 no.1
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• pp.27-35
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• 1991

An interstitial radiofrequency needle electrode system was constructed for interstitial heating of brain tissue. Radiofrequency electrodes with Thermotron RF 8 were tested in an agar phantom and in a normal canine brain to determine how variations in physical factors affected temperature distributions. Temperature distributions were checked after heating with 1 mm diameter needle electrode implants on the corners of 1 and 2 cm squares in a phantom and plot isotherms for various electrodes arrangement. We observed that the 1 cm square array would heat a volume with a 1.25 cm radius circular field cross section to therapeutic temperatures ($90\%$ relative SAR using Tm) and the 2 cm square array with a 1.75 cm radius rectangular field with central inhomogeneity. With 2 cm long electrode implants, we observed that the 1 cm square array would heat a 3 cm long sagittal section to therapeutic temperature ($90\%$ relative SAR using Tm). We found that radiofrequency electrodes could be selected to match the length of the heating area without affecting its performance. The histopathological changes associated with RF heating of normal canine brains have been correlated with thermal distributions. RF needle electrode heating was applied for 50min to generate tissue temperatures of $43^{\circ}C$. We obtained a quarter of the heated tissue material immediately after heating and sacrificed at intervals from $7\sim30$days. The acute stage (immediately after heating) was demonstrated by liquefactive necrosis, pyknosis of neuronal element in the gray matter and by some polymer-phonuclear leukocytes infiltration. The appearance of lipid-laden macrophages surrounding the area of liquefaction necrosis was demonstrated in all three sacrificed dogs. Mild gliosis occurring around the necrosis was demonstrated in the last sacrificed (Days 30) canine brain.

• Journal of the Korean Home Economics Association
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• v.46 no.4
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• pp.47-59
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• 2008

With increasing numbers of immigrant workers in Korea, the supply of socially and culturally acceptable housing has become an important issue. The purpose of this study was to analyze the state of Goryo-in housing and domestic living conditions in metropolitan areas of Korea. This study will present essential information directly relevant to the establishment of practical housing policy for Goryo-in in Korea. Furthermore, data collected and analyzed here will enable comparative investigation with Goryo-ins who live in Russia and Central Asia. Using ethnographic methodologies, we examined 20 Goryo-in households in relation to their usage of domestic space. The following conclusion were established; 1). The most popular L D K(Living Dining Kitchen)type consisted of kitchen plus one or two bedrooms. The majority of households lived in quarters with separated kitchen and living room areas. 2). Most households had a washing machine in the bathroom due to a lack of space, and they regarded the bathtub and the drain hole of the bathroom as very necessary. The Goryo-ins interviewed preferred quarters with separate bathroom and toilet areas, in order to allow simultaneous use. 3). Their most preferred seating style was chairs, while making Kimchi at home was not very popular. 4). All respondents took their shoes off and wore slippers at home, while also indicating a preference for designated shoes space at the entrance to the house. 5) Half of the households had a carpet or mat in the bedroom or living room, both for keeping warm and aesthetic reasons. 6). All households had modified Ondol heating system and demonstrated satisfaction with this. The majority of Goryo-ins interviewed had a different living style compared to households in Russia and Central Asia which were related to less favorable economic conditions in Korea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.9
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• pp.1477-1484
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• 2005

The effects of various seasoning components, pH of seasoning solution, heating time and storage temperature were investigated on the color and textural properties of the salted radish root (nanmooji) The effects of individual seasoning components in the salted radish root, additives of polyphosphate (AD3), citric acid (AD5), malic acid (AD2) delayed the color changes and softening more, compared to control soaked in water. On the other hand, additives of potassium sorbate (AD1), succinic acid (AD7), MSG (AD8), saccharin (AD6) accelerated the color changes and softening of the salted radish roots. The effects of pH of seasoning solution($X_1$), and heating time ($X_2$) were central composite design and response surface analysis. R- square represented dependent variables correlated independent variables ($X_1,\;X_2$), showed over 0.8 in the color and area value calculated thickness and firmness of salted radish root. Especially, R- square of 'b' represented 'yellow-green' was 0.899. And the result of crossing analysis of individual independent variables ($X_1,\;X_2$), showed that both independent variables had significant effects on the color and textural changes of the salted radish root. The salted radish root increased its color changes and softening, rapidly at $40^{\circ}C$, compared to the other storage temperatures at most storage periods.

• KIEAE Journal
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• v.16 no.1
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• pp.21-28
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• 2016

Purpose: The purpose of this study is to analyze & suggest the variation of energy consumption consequent on thermal insulation performance strengthening from early 2000s when modernization of barracks began until the present targeting a large barracks. Method: To carry out this research, this study surveyed the standard of thermal insulation by year, which is being applied to a barracks by conducting literature search, and selected the standard model for a barracks. Also, this study analyzed energy consumption by year & region by performing simulation(ECO2)of the selected standard model. Result: As a result, it was analyzed that in case of a building which was completed in 2015, the energy consumption for air-conditioning & heating, lighting, and hot water supply over the year 2000 reduced by 11% on the average in central district, 10% on the average in southern district, and 17% on the average in Jeju, respectively.

• Journal of Environmental Impact Assessment
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• v.19 no.6
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• pp.591-605
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• 2010

Cool roofs are currently being emerged as one of important mechanism to save energy in relation to the building. This paper reviews worldwide experiences (USA, Japan and EU etc) for the potential benefits cool roofs offer in relation to building energy saving for comparison purposes. It is confirmed that there is a significant potential to the energy saving by introducing the cool roof in a Korean climate because of similarity in terms of HDD (Heating Degree Day) and CDD (Cooling Degree Day) as those countries reviewed. Such a comparative study highlights that the type of measurements performed and the quantitative parameters reported from the countries should be standardized in Korean context in order to implement further comparable experiments for scientifically sound investigations. It is anticipated that this research output could be used as a valuable reference in implementing a Nation-wide cool roofing strategy in the central and local governments since a suitable technical, more objective direction has been proposed based on the measured, fully quantitative performance of the involved components of a cool roof system in the global context. From this critical review, a very important step has been made concerning the practicality of cool roof in Korean context. Ultimately, the suggestion in this paper will greatly contribute to opening new possibilities for introducing cool roof in this country, proposed as an initial aim of this paper.