• Journal of the Korea Institute of Building Construction
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• v.20 no.5
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• pp.417-423
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• 2020

In order to reduce cooling and heating, which is 40% of the energy consumption of buildings, it is important to improve the insulation of the skin. In order to improve the existing insulation, research is being conducted to apply a vacuum insulation panel(VIP) to buildings. However, VIP cannot be repaired, so we considered the metal vacuum insulation panel. Since the core of the metal vacuum pressure and have low thermal conductivity, foam concrete is adopted. However, preliminary experiments confirmed that the time to reach 0.001torr differs depending on the amount and nature of the bubbles. This effect is determined by the type of foaming agent and the density of the bubble slurry, the vacuum delivery time is determined to be the optimum foam concrete conditions are necessary. Therfore, this study aims to present basic data applicable to core materials by measuring vacuum delivery time and thermal conductivity change according to the foaming agent type and foam slurry density of foam large concrete which is core material of metal vacuum insulation panel. Experimental results and analysis show that compressive strength can be used regardless of the type of foam, In terms of thermal conductivity, it is stable to use vegetable foaming agents at 0.9g/㎤ or less. In terms of the vacuum delivery time, the foaming agent appeared similar regardless of the type of foaming agent, but it is considered suitable to use vegetable foaming agent based on compressive strength and thermal conductivity.

• Journal of the Korean Dietetic Association
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• v.23 no.3
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• pp.263-273
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• 2017

Numerous studies have investigated quantifying dietary intake according to the weight status of children and adolescents. However, studies on differences in quality among diets remain scarce. This study compared diet quality by weight status and examined correlations between quality of diet and obesity in children and adolescents. Two hundred fourteen children and adolescents aged between 9 and 18 years participated in this study (Normal weight n=104, Obesity n=110). The data related to food intake were investigated by dietary records, Diet Quality Index-International (DQI-I), and Nutrition Quotient (NQ) and then compared with Dietary Reference Intakes for Korean (KDRIs). In DQI-I, moderation factor (control of unhealthy foods) score was 21.7 in the normal weight group and 19.5 in the obesity group. The normal weight group showed a higher score for moderation factor than the obesity group (P<0.001). Compared with KDRIs, vitamin $B_6$, folate, vitamin C, vitamin E, calcium, potassium, and zinc intakes were insufficient in both groups. Multiple logistic regression analysis revealed that DQI-I moderation was negatively associated with obesity (OR=0.77, 95% CI 0.69-0.87) after adjustment for age, gender, income, and total energy intake. Our results suggest that children and adolescents require nutritional education to understand the importance of vitamin and mineral consumption. Especially, education for children and adolescents with obesity needs to emphasize moderation of nutrient intake that can cause diseases with hyper-ingestion such as sodium and high calorie-low nutrition foods.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.66-72
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• 2018

Corn stover is known as a good candidate for a functional food ingredient when the main lignocellulosic material, lignin, is used as bioactive materials as form of polyphenolic compounds. The purpose of this study was to determine the microwave extraction conditions under which total phenolic compounds (TPC) and flavonoid contents of corn stover were maximized. Microwave-assisted extracts using sulfuric acid ranging from 0 to 1.0 mol with extraction time between 40 and 240 sec were conducted by using response surface methodology (RSM). Microwave power showed significant effects (p<0.05) and the concentrations of TPC and flavonoids increased with increased level of microwave power and extraction time. The optimum conditions for corn stover extraction were determined as 698.6 W, 240 sec, and 0 mol sulfuric acid, and the predicted value of TPC and flavonoid is 82.4 mg GAE/g DM and 18.1 mg/g DM, respectively. Microwave extraction was evaluated as an economic process with low energy consumption, short extraction and high extraction yield of bioactive including TPC and flavonoids compared to conventional extractions.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.6
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• pp.683-690
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• 2006

Reducing power consumption to extend network lifetime is one of the most important challenges in designing wireless sensor networks. One promising approach to conserving system energy is to keep only a minimal number of sensors active and put others into low-powered sleep mode, while the active sensors can maintain a connected covet set for the target area. The problem of computing such minimum working sensor set is NP-hard. In this paper, a centralized Voronoi tessellation (CVT) based approximate algorithm is proposed to construct the near optimal cover set. When sensor's communication radius is at least twice of its sensing radius, the covet set is connected at the same time; In case of sensor's communication radius is smaller than twice of its sensing radius, a connection scheme is proposed to calculate the assistant nodes needed for constructing the connectivity of the cover set. Finally, the performance of the proposed algorithm is evaluated through theoretical analysis and extensive numerical experiments. Experimental results show that the proposed algorithm outperforms the greedy algorithm in terms of the runtime and the size of the constructed connected cover set.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.252-258
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• 2018

A larger energy consumption and concentration of population induced green house gas glowing and heat island effect in the urban space. Roof green system was a effect method to reduce green house gas and heat concentration in the city. Therefore, construction of this system was increasing. Most of lightweight soil used in roof green system was perlite, but this caused dust and skin disease. So it needed to develop another new lightweight soli for roof green system. Meanwhile, a thermoelectric power plant generated bottom ash as a by-product. According to previous research, bottom ash could be used for artificial lightweight soil with 60 wt% of mixing rate. But this study was proceed to develop a artificial lightweight soil using bottom ash with higher mixing rate by 65 wt% and different organic ingredients. First, physical and chemical properties of bottom ash was investigated. Then test according to landscaping design standard was proceeded for various artificial lightweight soil mix types using bottom ash, bark, compost and coco peat. As a result, the artificial lightweight soil with 65% of bottom ash, 30% of bark and 5% of compost was suitable for low and middle range of soil standard.

• Journal of IKEEE
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• v.23 no.2
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• pp.743-746
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• 2019

In this paper we proposed a new ocean radiation automatic monitoring system. The proposed system has the following characteristics: First, using NaI + PVT mixed detectors, the response speed is fast and precision analysis is possible. Second, the application of temperature compensation algorithm to scintillator-type sensors does not require additional cooling devices and enables stable operation in the changing ocean environment. Third, since cooling system is not needed, electricity consumption is low, and electricity can be supplied reliably by utilizing solar energy, which can be installed at the observation deck of ocean environment. Fourth, using GPS and wireless communications, accurate location information and real-time data transmission function for measurement areas enables immediate warning response in the event of nuclear accidents such as those involving neighboring countries. The results tested by the authorized testing agency to assess the performance of the proposed system were measured in the range of $5{\mu}Sv/h$ to 15mSv/h, which is the highest level in the world, and the accuracy was determined to be ${\pm}8.1%$, making normal operation below the international standard ${\pm}15%$. The internal environmental grade (waterproof) was achieved, and the rate of variation was measured within 5% at operating temperature of $-20^{\circ}C$ to $50^{\circ}C$ and stability was verified. Since the measured value change rate was measured within 10% after the vibration test, it was confirmed that there will be no change in the measured value due to vibration in the ocean environment caused by waves.

• Journal of Nutrition and Health
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• v.35 no.4
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• pp.480-488
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• 2002

This study was performed to document the association between obesity, a major risk factor for chronic diseases, and dietary pattern in Korean elderly. The subjects were 595 men and women aged 60-89 years. The subjects were classified into 4 groups based on BMI: under weight, BMI < 18.5, normal weight, 18.5 $\leq$ BMI 22.9; overweight, 23.0 BMI 24.9; and obese BMI $\geq$ 25.0. Dietary intakes by 24-hr recall, blood pressure, anthropometric parameters and health eating index (HEI) were measured. Underweight group was excluded for data analysis doe to small number of subjects, and age-adjusted measurements were compared among normal, overweight and obese groups. The mean anthropometric values for males and females were 23.7 and 24.8 kg/$m^2$ for BMI, 0.90 and 0.86 for WHR and 140.7 and 138.8 mmHg for SBP, respectively. The mean intakes of energy, Ca, vitamin A, vitamin B$_2$, and vitamin E did not meet Korean RDA for elderly. Intakes of fat and cholesterol were low: the percent energy from fat for male and female subjects were 19.1% and 18.1% and mean cholesterol intakes were 208 mg and 152 mg, respectively. Judging by HEI score, dietary quality was better in females than in male subjects. The mean BMI of normal, over and obese groups were 21.4, 23.9, 26.7 kg/$m^2$ in male subjects and 21.6, 23.9, 27.1 kg/$m^2$ in female subjects. WHR, SBP and TSF were increased with increasing BMI No association was found between BMI and nutrient intakes and/or food consumption pattern. However, a tendency was shown that the overweight group reported higher intakes in most nutrients compared to normal and obese groups. This study implies that with increasing BMI, anthropometric risk factors, such as WHR, TSF, and blood pressure were Increased, however, no significant differences were found in nutrient intakes and food patterns. Energy and fat intakes do not seem to be a cause for obesity in Korean elderly.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.12
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• pp.1234-1268
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• 2004

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2002 and 2003 has been carried out. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment/design. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation in diverse facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat transfer, humidity was also interesting to promote comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing research topics. Well developed CFD technologies were widely applied for analysis and design of various facilities and their systems. (2) Heat transfer characteristics of enhanced finned tube heat exchangers and heat sinks were extensively investigated. Experimental studies on the boiling heat transfer, vortex generators, fluidized bed heat exchangers, and frosting and defrosting characteristics were also conducted. In addition, the numerical simulations on various heat exchangers were performed and reported to show heat transfer characteristics and performance of the heat exchanger. (3) A review of the recent studies shows that the performance analysis of heat pump have been made by various simulations and experiments. Progresses have been made specifically on the multi-type heat pump systems and other heat pump systems in which exhaust energy is utilized. The performance characteristics of heat pipe have been studied numerically and experimentally, which proves the validity of the developed simulation programs. The effect of various factors on the heat pipe performance has also been examined. Studies of the ice storage system have been focused on the operational characteristics of the system and on the basics of thermal storage materials. Researches into the phase change have been carried out steadily. Several papers deal with the cycle analysis of a few thermodynamic systems which are very useful in the field of air-conditioning and refrigeration. (4) Recent studies on refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement when new alternative refrigerants are applied. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and new alternative refrigerants including natural refrigerants. Efficiency of various compressors and performance of new expansion devices are also dealt with for better design of refrigeration/air conditioning system. In addition to the studies related with thermophysical properties of refrigerant mixtures, studies on new refrigerants are also carried out. It should be noted that the researches on two-phase flow are constantly carried out. (5) A review of the recent studies on absorption refrigeration system indicates that heat and mass transfer enhancement is the key factor in improving the system performance. Various experiments have been carried out and diverse simulation models have been presented. Study on the small scale absorption refrigeration system draws a new attention. Cooling tower was also the research object in the respect of enhancement its efficiency, and performance analysis and optimization was carried out. (6) Based on a review of recent studies on indoor thermal environment and building service systems, it is noticed that research issues have mainly focused on several innovative systems such as personal environmental modules, air-barrier type perimeterless system with UFAC, radiant floor cooling system, etc. New approaches are highlighted for improving indoor environmental conditions and minimizing energy consumption, various activities of building energy management and cost-benefit analysis for economic evaluation.

• Journal of Nutrition and Health
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• v.52 no.1
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• pp.47-57
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• 2019

Purpose: This study was conducted to investigate the relationship between atopic dermatitis and dietary fat and fatty acid (FA) intakes in 9 ~ 11 year old children. Methods: We analyzed data from the combined 2013 ~ 2015 KNHANES (Korean National Health and Nutrition Examination Survey). Subjects were divided into two groups according to atopic dermatitis (AD); with AD and without AD. Data pertaining to macronutrients and FA intakes were obtained by a single 24-h dietary recall. Food sources were identified based on the amounts of total fat and FA consumption according to each food. The associations between each FA intake and atopic dermatitis were analyzed using simple and multiple logistic regression analyses. Age, sex, body mass index (BMI) and income levels were adjusted as covariates. Results: Of the participants, 17.69% suffered from atopic dermatitis. Children with AD had significantly lower fat percentages of total energy and higher carbohydrate percentages of total energy than normal children. Percentages of energy and intakes of polyunsaturated fatty acid (PUFA), n-3 FA and n-6 FA in children with AD were significantly lower than those in normal children. In the FA, linoleic acid, ${\gamma}$-linoleic acid and ${\alpha}$-linolenic acid levels of children with AD were significantly lower than those of normal children. However, the P/S ratio and n-6/n-3 ratio did not differ significantly between children with AD and normal children. Soybean oil was the main contributor to PUFA, n-3 FA and n-6 FA in both groups, while perilla seed oil and mackerel were the major food sources of n-3 FA in children with atopic dermatitis. Atopic dermatitis was significantly correlated with low-fat and high-carbohydrate diets. The adjusted odds ratios were 0.966, 0.776 and 0.963 for PUFA, n-3 FA, and n-6 FA intakes, respectively. Conclusion: The present study provides reliable evidence regarding the relationship between fat and FA intakes and AD in Korean children 9 ~ 11 years of age.

• Korean Journal of Soil Science and Fertilizer
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• v.2 no.1
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• pp.53-68
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• 1969

The nutriophysiological response of rice plant to root environment was investigated with eye observation of root development and rhizosphere in situation. The results may be summarized as follows: 1) The quick decomposition of organic matter, added in low yield soil, caused that the origainal organic matter content was reached very quickly, in spite of it low value. In high yield soil the reverse was seen. 2) In low yield soil root development, root activity and T/R value were very low, whereas addition of organic matter lowered them still wore. This might be contributed to gas bubbles around the root by the decomposition of organic matter. 3) Varietal difference in the response to root environment was clear. Suwon 82 was more susceptible to growth-inhibitine conditions on low-yield soil than Norin 25. 4) Potassium uptake was mostly hindered by organic matter, while some factors in soil hindered mostly posphorus uptake. When the organic matter was added to such soil, the effect of them resulted in multiple interaction. 5) The root activity showed a correlation coeffieient of 0.839, 0.834 and 0.948 at 1% level with the number of root, yield of aerial part and root yield, respectively. At 5% level the root-activity showed correlation-coefficient of 0.751, 0.670 and 0.769 with the uptake of the aerial part of respectively. N, P and K and a correlation-coefficient of 0.729, 0.742 and 0.815 with the uptake of the root of respectively N.P. and K. So especially for K-uptake a high correlation with the root-activity was found. 6) The nitrogen content of the roots in low-yield soil was higher than in high-yield soil, while the content in the upper part showed the reverse. It may suggest ammonium toxicity in the root. In low-yield soil Potassium and Phosphorus content was low in both the root and aerial part, and in the latter particularly in the culm and leaf sheath. 7) The content of reducing sugar, non-recuding sugar, starh and eugar, total carbohydrates in the aerial part of plants in low yield soil was higher than in high yield soil. The content of them, especially of reducing sugar in the roots was lower. It may be caused by abnormal metabolic consumption of sugar in the root. 8) Sulfur content was very high in the aerial part, especially in leaf blade of plants on low yield soil and $P_2O_5/S$ value of the leaf blade was one fifth of that in high yield soil. It suggests a possible toxic effect of sulfate ion on photophosphorization. 9) The high value of $Fe/P_2O_5$ of the aerial part of plants in low yield soil suggests the possible formation of solid $Fe/PO_4$ as a mechanical hindrance for the translocation of nutrients. 10) Translocation of nutrients in the plant was very poor and most nutrients were accumulated in the root in low yield soil. That might contributed to the lack of energy sources and mechanical hindrance. 11) The amount of roots in high yield soil, was greater than that in low yield soil. The in high-yield soil was deep, distribution of the roots whereas in the low-yield soil the root-distribution was mainly in the top-layer. Without application of Nitrogen fertilizer the roots were mainly distributed in the upper 7cm. of topsoil. With 120 kg N/ha. root were more concentrated in the layer between 7cm. and 14cm. depth. The amount of roots increased with the amount of fertilizer applied.