• Journal of Korean Society of Environmental Engineers
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• v.36 no.7
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• pp.461-468
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• 2014

Biochar is a carbon rich solid produced by the pyrolysis of biomass such as energy crops, forestry residues, and wood wastes. Biochar returned to soil is to mitigate climate change and the feedstock of wood wastes reduces fossil fuel consumption as well as disposal costs. This study was practiced to evaluate a biochar system by gasification in terms of global warming regarding the soil application of the produced biochar. Life cycle assessment methodology was used to analyze the environmental impacts of the system, and the functional unit was 1 tonne of wood wastes. The result shows that the biochar system by using wood wastes as feedstock produces 4.048E-01 $kgCO_2-eq$ from the pre-treatment process as chipping and drying, 4.579E-01 $kgCO_2-eq$ from the pyrolysis process, and 9.070E-02 $kgCO_2-eq$ from the spreading to agricultural land, therefore total 9.534E-01 $kgCO_2-eq$ are generated. About 252 kg of $CO_2$ is still stored in the produced biochar in soil after carbon offsetting of the system. Therefore, the net carbon of the system is -251 kg of $CO_2-eq$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3389-3395
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• 2014

Conventional methods, such as the clock time control method and temperature difference control method, for defrost control often encounter mal-defrost and a waste of energy. Therefore, a more efficient method is needed to control defrosting precisely. A photoelectric sensor unit consisting of an emitter and a collector was installed in the front of outdoor heat exchanger. Accurate defrost control was performed by monitoring and using the change in output voltage according to the presence of frost. In this study, experiments were performed to determine if the performance and characteristic curves obtained using the clock time control method can be reproduced using a photoelectric sensor under the heating and defrosting capacity test condition described at KS C 9306. The output voltage of the phototransistor (receiver) and heating capacity, power consumption, and surface temperature of the outdoor heat exchanger, were compared. The results showed that photoelectric sensors can be used as a defrost control method. On-off control timing of the clock time defrosting method was in good agreement with those predicted by the output voltage of the photoelectric sensor.

• Nutrition Research and Practice
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• v.4 no.3
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• pp.229-234
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• 2010

Recently, we found and analyzed vitamin $B_{12}$ in some Korean traditional plant foods which had not reported, yet. This study was to investigate vitamin $B_{12}$ intake and its dietary sources and the vitamin $B_{12}$ status in the very old elderly Koreans. We measured serum vitamin $B_{12}$ level and estimated the amounts of vitamin $B_{12}$ intake from different dietary sources in female elderly Koreans aged 85 and over who had consumed a relatively low animal traditional diet for the whole life. The average age of the subjects (n = 127) was 98.0 years (85-108 years). The assessment on energy and nutrient intake involved a one-day 24-hour recall, and serum vitamin $B_{12}$ concentration was measured by radioimmunoassay. Overall diet pattern was not different between the 85-99 yr-old group and centenarians, except centenarians were taking more dairy product. The average ratio of plant food to animal food consumption was 87.5:12.5 in weight. The average vitamin $B_{12}$ intake of our subjects was 3.2 ${\mu}g$, and 52.7% of subjects consumed under estimated average requirement, 2.0 ${\mu}g$/day. On dietary source, 67.3% of dietary vitamin $B_{12}$ was from meat, eggs and fishes and 30.6% was from plant foods, such as soybean-fermented foods, seaweeds, and kimchi. The average serum vitamin $B_{12}$ concentration was 450.5 pg/mL, and low serum vitamin $B_{12}$ (< 200 pg/mL) was found in 9.6% of subjects. Dietary vitamin $B_{12}$ intake was significantly lower in subjects with low serum vitamin $B_{12}$ (0.79 ${\mu}g$/day) than those with normal serum vitamin $B_{12}$ (3.47 ${\mu}g$/day). There were no significant difference in vitamin $B_{12}$ intake and its dietary sources and serum vitamin $B_{12}$ level between the 85-99 yr- old group and centenarians. In conclusion, several plant-origin foods including seaweed, soybean-fermented foods, and kimchi, may contribute significantly to good vitamin $B_{12}$ status in very old elderly Koreans.

• Journal of Nutrition and Health
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• v.31 no.9
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• pp.1481-1497
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• 1998

The purpose of this study was to determine the relation between serum lipid profiles, apolipoprotein E phenotype, and dietary patterns in a cross-section of healthy individuals from Cheju-Do. Age, gender, anthropometric measurements, blood pressure, dietary consumption, drinking / smoking habits and menopausal status were surveyed. Total cholesterol, LDL-cholesterol, HDL-cholesterol, triglyceride, fasting blood glucose, and insulin levels were measured from overnight fasting blood. The study involved a total of 286 individuals(147 men and 139 women) between the ages of 20 and 60 years old. All of the subjects were recruited from a population of healthy individuals living in Cheju-Do. The results of the study are as follows : 1) Among the males, those in their 20's had the maximum food intake, while those in their 40's had the minimum food intake. For the females, food intake was the highest for those in their 30's. Energy and nutrient intakes were directly proportional to the amount of food intake. Men in their 30's were heavier than other men and women in their 40's were heavier than other women. The activity index for men in their 20's and 30's appeared to be lower than that of men above 40. The activity index of women in their 20's appeared to be lowest among all aged groups, and the index appeared to increase from the age of 30 onwards. 2) In terms of changes In serum constituents with age, men in their 40's appeared to have the highest levels of serum constituents such as lipids, glucose, and insulin. Men in their 50's showed the highest levels of serum LDL-cholesterol and glucose. Men in their 30's showed peak levels of serum triglycerides. On the other hand, women in their 50's appeared to have peak levels of serum total cholesterol, LDL-cholesterol, and triglycerides. There was no ch:ange with age in HDL-cholesterol and insulin levels for men and women. The percentage of the subjects had the following apo E phenotypes : E3/3, 91.3% ; E3/2, 5.4% ; E4/3, 2.5% ; E4/2, 0.7%. Lee's reserch with Korean female college students showed that the percentage of ApoE3/3, E3/2, E 4/2, E4/3, and E4/4 were 84.8%, 6.7%, 6.7%, 0.9%, 0.9%, respectively. The number of samples with ApoE mutation was so small that there was no statistical significance in the relation between apolipoprotein E phenotype and se겨m lipids. 3) To investigate the relati onship between weight and serum constituents, the subjects of this study were divided into three groups by BMI underweight, normal weight, and overweight. The serum constituents of men and women below the age 40 in the overweight groups belonged to the normal domain. On the other hand, serum cholesterol levels of both men and women above the age 40 in the overweight groups remained in the borderline-high region(above 200mg/dl), and the mean value of LDL-cholesterol(above 130mg/dl) and triglycerides of men were above normal. Fasting blood glucose levels also remained in the borderline-high region. Total cholesterol levels of women above the age 40 in the overweight group was in the borderline-high region. (Korean J Nutrition 31(9) : 1481-1497, 1998)

• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.236-242
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• 2017

The conversion of marine biomass to renewable energy has been considered an alternative to fossil fuels. Butanol, in particular, can be used directly as a fuel. In this experiment, the brown alga Undaria pinnatifida was selected as a biomass for biobutanol production. Hyper thermal (HT) acid hydrolysis was used as an acid hydrolysis method to produce monosaccharides. The optimal pretreatment conditions for U. pinnatifida were determined as slurry with 10% (w/v) U. pinnatifida content and 270 mM $H_2SO_4$, and heating at $160^{\circ}C$ for 7.5 min. Enzymatic saccharification was carried out with Celluclast 1.5 L, Viscozyme L, and Ultraflo Max. The optimal saccharification condition was 12 U/ml Viscozyme L. Fermentations were carried out for the production of acetone, butanol, and ethanol by Clostridium acetobutylicum KCTC 1724, Clostridium beijerinckii KCTC 1785, and Clostridium tyrobutyricum KCTC 5387. The fermentations were carried out using a pH-control. The optimal ABE fermentation condition determined using C. acetobutylicum KCTC 1724 adapted to 160 g/l mannitol. An ABE concentration of 9.05 g/l (0.99 g/l acetone, 5.62 g/l butanol, 2.44 g/l ethanol) was obtained by the consumption of 24.14 g/l monosaccharide with $Y_{ABE}$ of 0.37 in pH 5.0.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.12
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• pp.863-870
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• 2012

The market trends of automatic meter reading associated with smart water meters were investigated. Also, recent developments and field applications of key technology for automatic meter reading associated with smart water meters were analyzed. Smart water meters have been manufactured mostly in United States and Europe and have been expanded their business to Asia. Integrated water management system combining with the additional functions such as real-time consumption metering, cost notification, water conservation, leak detection, water quality monitoring, and flow control have been operated in automatic meter reading. Both water quality and quantity data measured from smart water meters and sensors were transferred to data concentration units through neighborhood area network, and then were transferred to integrated server through wide area network. The data transfer methods were determined by comprehensively considering urban scale, density of smart water meters, power supply and network topologies. Common data collection methods such as fixed network to data concentation units, vehicles drive by, people walk by, and drone fly by have been applied. The automatic meter reading associated with smart water meters are spread throughout the world, and both water and energy savings result in saving the money and reducing the greenhouse gases emission.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.8
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• pp.411-419
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• 2016

The objective of this study was to evaluate the application possibility of tube type electrolysis module system using recirculation process through removal organic matters and nitrogen in the pigment wastewater. The tube type electrolysis module consisted of a inner rod anode and an outer tube cathode. Material used for anode was titanium electroplated with $RuO_2$. Stainless steel was used for cathode. It was observed that the pollutant removal efficiency was increased according to the decrease of flowrate and increase of current density. When the retention time in tube type electrolysis module system was 180 min, chlorate concentration was 382.4~519.6 mg/L. The chlorate production was one of the major factors in electrochemical oxidation of tube type electrolysis module system using recirculation process used in this research. The pollutant removal efficiencies from the bench scale tube type electrolysis module system using recirculation operated under the electric charge of $4,500C/dm^2$ showed the $COD_{Mn}$ 89.6%, $COD_{Cr}$ 67.8%, T-N 96.8%, and Color 74.2%, respectively and energy consumption was $5.18kWh/m^3$.

• Journal of KIISE:Information Networking
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• v.34 no.6
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• pp.446-457
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• 2007

In wireless sensor network, to provide the proper responses quickly for diverse events, wireless sensor nodes have to cooperate with each other. For successful cooperation, the time synchronization among sensor nodes is an important requirement for application execution. In the wireless sensor network, the message packets including time information are used for the time synchronization. However, the transmission of many message packets will exhaust the battery of wireless sensor nodes. Since wireless sensor nodes works on the limited battery capacity, the excessive transmission of message packets has an negative impact upon their lifetime. In this paper, the Reference Interpolation Protocol (RIP) is proposed to reduce the number of message packets for the time synchronization. The proposed method performs the time interpolation between the reference packet's time and the global time of the base station. The proposed method completes the synchronization operation with only 2 message packets when compared to the previous Reference Broadcast Synchronization (RBS) technique. Due to the simple synchronization procedure, our method greatly reduces the number of synchronization messages and showed the 12.7 times less power consumption than the RBS method. From the decrease in the transmission of message packets, the convergence time among wireless sensor nodes is shortened and the lifetime of wireless sensor nodes is also prolonged as much as the amount of saved battery energy.

• Journal of KIISE:Information Networking
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• v.34 no.6
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• pp.475-482
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• 2007

Mobile nodes in ad-hoc wireless networks play roles of router as well as host. Movement of nodes causes network topology changes, which make existing routing information be modified. Therefore many routing protocols for ad-hoc networks were suggested in the literature. In this paper, we suggest an enhanced automatic route shortening method for dynamic source routing(DSR) protocol. DSR is a request/response based protocol which has low routing overhead owing to node movement. The current automatic route shortening is performed on the only nodes which belong to the source route of packets. On the contrary, our suggested method allows all neighbor nodes hearing the packet to participate in automatic route shortening. It makes all possible route shortenings be performed. So we maintain maximal shortened routes of ongoing data connections. Simulation results with ns2 show that our method pays small extra protocol overhead for ARS, but increases the ratio of successful packet transmissions and the number of ARSs performed in our mechanism is from 2 to 5 times higher than in original ARS mechanism and therefore it will improve the network-wide energy consumption in wireless ad-hoc networks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.311-316
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• 2018

As the lives of people have improved, the demand for improved indoor air quality has increased. Various methods are used to remove biological air pollutants, such as UV/photocatalytic devices and ozone generators. However, these methods have disadvantages such as energy consumption, high corrosivity and toxicity. To overcome these disadvantages, an antibacterial copper filter was fabricated and its antimicrobial activity was then tested against two fungi (P. pinophilum, C. globosum) and one bacteria (S. aureus) Moreover, the ability to remove suspended microorganisms was tested step by step from the chamber stage to the air conditioning system. The results revealed 100% antimicrobial activity after 24 hours for the two fungi, while this value was 99.9% after 18 hours for the bacteria. Moreover, the antibacterial activity was higher when the chamber and air purifier were used than was obtained using a general antibacterial HEPA filter. Also, as a filter for system air conditioner, the antibacterial activity was lowered in offices and hospitals. In conclusion, the copper filter was found to have sufficient antibacterial activity for use as an antibacterial filter; however, further research on its preparation methods and materials is warranted.