• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.554-556
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• 2022

Due to the recent surge in single-person households, solitary death is drawing attention as an important social problem. We herein develop an adaptive monitoring system using RFID to protect the socially disadvantaged who are exposed to the risk of solitary death. The developed system consists of a wearable RFID tag, an RFID reader attached to the residence, and a user monitoring App. The developed system measures the retention time of a user with a wearable tag in a place where a reader is attached. When the retention time exceeds an adaptively determined threshold, an emergency notification is sent to the caregiver. We verify the effectiveness of the designed system by implementing a prototype modeling a residence based on Arduino.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.6
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• pp.24-29
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• 2002

Nitrate removal rate in three cattail wetland cells was investigated. They were a part of a pond-wetland system for stream water treatment demonstration. The system was composed of two ponds and six wetland cells. The acreage of each cell was approximately $150m^2$. The earth works for the system were finished from April 2000 to May 2000 and cattails were planted in the three cells in June 2000. Waters of Sinyang Stream flowing into Kohung Estuarine Lake were pumped into a primary pond, whose effluent was discharged into a secondary pond. The reservoir was formed by a tidal marsh reclamation project and located in southern coastal area of Korean Peninsula. Effluents from the secondary pond were funneled into the three cells. Volumes and water quality of inflow and outflow were analyzed from July 2000 through January 2001. Inflow and outflow averaged $20.2m^3/day$ and $19.8m^3/day$, respectively. Hydraulic retention time was about 1.6 days. Average influent and effluent nitrate concentration was $1.98mg/{\ell}$, $1.38mg/{\ell}$, respectively. Nitrate removal rate averaged $82.6mg\;m^{-2}\;day^{-1}$. Seasonal changes of nitrate retention rates were closely related to those of wetland cell temperatures. The average nitrate removal rate in the cells was a little lower, compared with that of $125.0mg\;m^{-2}\;day^{-1}$ for the wetlands operating in North America. This could be attributed to the initial stage of the cells and inclusion of three cold months into the seven-month study period. Root rhizosphere in wetland soils and litter-soil layers on cell bottoms could not developed. Increase of standing density of cattails within a few years will establish both root zones suitable for the nitrification of ammonia to nitrates and substrates beneficial to the denitrification of nitrates into nitrogen gases, which may lead to increase of the nitrate retention rate.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.6 no.6
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• pp.49-55
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• 2003

Total phosphorous removal rate was examined of a subsurface-flow treatment wetland system which was constructed on floodplain in the down reach of the Kwangju Stream in Korea from May to June 2001. Its dimensions were 29 meter in length, 9 meter in width and 0.65 meter in depth. A bottom layer of 45 cm in depth was filled with crushed granite with about 15~30 mm in diameter and a middle layer of 10 cm in depth had pea pebbles with about 10 mm in diameter. An upper layer of 5 cm in depth contained course sand. Reeds(Phragmites australis) were transplanted on the surface of the system. They were dug out of natural wetlands and stems were cut at about 40 cm height from their bottom ends. Water of the Kwangju Stream flowed from a submerged dam into it via a pipe by gravity flow and treated effluent was funneled back into the Stream. The number of reed stems increased from 80 stems/$m^2$ in July 2001 to 136 stems/$m^2$ in September 2001. The hight of stems was 44.2 cm in July 2001 and 75.3 cm in September 2001. The establishment of reeds at early operating stage of the system was good. Volume and water quality of inflow and outflow were investigated from July 2001 through December 2001. The average inflow was 40 $m^3$/day and hydraulic detention time was about 1.5 days. The concentration of total phosphorous n influent and effluent was 0.83 and 0.33 mg/L, respectively. The removal rate of total phosphorous averaged about 60%. The removal efficiency was slightly higher, compared with that of subsurface-flow wetlands operating in North America, whose retention rate of total phosphorous was reported to be about 56%. The good abatement rate could be attributed to sedimentation of particle phosphorous in pores of the media and adsorption of phosphorous to the biofilm developed on the surface of them. Increase of standing density of reeds within a few years will develop root zones which may lead to increment in the phosphorous retention rate.

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.518-521
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• 2004

Ginseng saponin was isolated from panax ginseng root using high-speed countercurrent chromatography (HSCCC). Preliminary studies were performed to optimize physical properties of two-phase solvent system and operating parameters including rotation speed of column, elution mode of mobile phase, and flow rate. Two-phase solvent system for isolation of ginseng saponins was composed of chloroform, water, and methanol as blending solvent. Chloroform-aqueous methanol (4:6) systems with various concentration of methanol in water were evaluated for retention of stationary phase in column. Retention of stationary phase decreased with increasing flow rate in tail-to-head elution mode using upper phase as mobile phase and head-to-tail elution mode using lower phase as mobile phase. Latter mode produced high retention at flow rate of 5 mL/min. Optimum conditions for isolation of saponin were chloroform/methanol/water (40/39/21) solvent system; mobile phase, of lower organic layer, flow rate, of 5 mL/min, head to tail elution mode, rotation speed, of 800 rpm, and sample injection, of $200{\mu}L$, Recovery yield of ginseng saponin from panax ginseng root extract by HSCCC was 63.6%, and the purity of HSCCC fractions was verified by TLC.

• Journal of Convergence for Information Technology
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• v.7 no.3
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• pp.83-90
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• 2017

The purpose of this study is to solve the limitations that the information security manager of company should recognize the personal information of all employees. In this study, we propose efficient personal information retention status management system to minimize information retention status of personal information and department by information security manager and departmental information security officer. To do this, we study the method of transferring the check result from the PVA system to the efficient personal information retention management system, also study ways to minimize the amount of personal information we hold. It is possible to minimize the possession of personal information by changing the one channel method managed by the information security administrator of the existing PVA system to the two channel method so that the information security manager and the information security officer can manage it.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.30 no.2
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• pp.86-99
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• 2017

Objectives : The purpose of this study is to compare atopic dermatitis and food allergy of Korean Medicine with those of western medicine. Methods : We examined the relationship between atopic dermatitis and food allergy mainly in digestive system abnormalities through literature review. Results : Food allergy is classified into categories such as diarrhea, abdominal pain and cough caused by retention of undigested food(食積) and pimples(癮疹) in Korean medicine. The side effects caused by specific immune reactions occur repeatedly due to exposure to specific food allergen or retention of undigested food. Atopic dermatitis and food allergy are often coexisting and deeply related. Digestive system abnormalities can result not only in indigestion but also in immune function abnormalities. Food allergies are known to cause atopic dermatitis and the influx of food antigens exacerbates atopic dermatitis. This corresponds to atopic dermatitis due to abnormal digestive system(脾胃) accompanied by fever(熱), wind(風), and weakness(虛) with focusing on dampness(濕). A typical example of the relationship between atopic dermatitis and food allergy in Korean medicine is Tae-yeul (胎熱). Tae-yeul refers to atopic dermatitis caused by a sensitization to reaction to the dietary antigens of the mother through the placenta during the fetal life with a unusual genetic disposition. Conclusions : We compared korean medicine with western medicine for atopic dermatitis and food allergy. Atopic dermatitis caused by abnormal immune function due to ingestion of food antigen corresponds to dermatitis due to retention of undigested food(食積), digestive system(脾胃臟) problems in korean medicine.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.4
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• pp.1-7
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• 1999

This study was carried out to simulate the change of various properties of recycled water when zero-discharge system was applied to a KOCC recycling process. contaminants such as chemical oxygen demand, anionic trash, and calcium hardness were gradually increased in the process water as the recycling was repeated . Especially, the increase of anionic trash and COD were closely related to the starch derived from corrugating adhesive in KOCC. Four kinds of water were compared in the preparation of handsheet to evaluate the performance of retention program. Waters used in this work were laboratory tab water, process water from Dong-II mill and the same one treated by UASB process, and closed white water prepared by KRICT. The result revealed that one the major factors fro reducing a retention power was the anioni trash accumulated in the recycled water.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.1
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• pp.93-96
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• 2000

Bone-anchored auricular prosthesis have been proved that was another apporach to the treatment of the defective external ear. A 19years old woman with hemifacial microsomia was treated with osseointegrated implants for the support of craniofacial prosthesis. 3 implants were placed in temporal region and craniofacial prosthesis was retained with telescopic magnet retention system. The literatures and surgical technique are reviewed and our experience is presented.

• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.134-139
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• 2006

Partial nitirification and denitrification process has been reported to be technically feasible and economically favorable, especially for wastewater treatment with high ammonium concentration or low Carbon/Nitrogen ratio. This research was performed to survey nitrite accumulation by nitritation in treating ADEPT effluent of piggery wastewater, which contains highly concentrated ammonia. To estimate the possibility of nitrite accumulation, DO concentration and SRT were investigated as key operational parameters. This result proved that nitritation to nitrite was steadily obtained under short sludge retention time. Oxygen limitation was proved to be just a subsidiary parameter. Energy efficiency of nitritation-denitritation process was higher than complete nitrification-denitrification because external carbon requirement for denitritation could be saved. Though the influent contained significant nonbiodegradable organic substrate, total nitrogen removal efficiency was more than 51% in nitritation-denitritation system.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.12 no.1
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• pp.2-11
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• 1983

The solar energy retention rate of a flat plate collector can be increased by increasing water flow rate through the collector which also increases the pumping energy incurred in obtaining that solar energy. The problem of optimal flow rate is formulated to fit within the framework of pontryagin's maximum principle and with a few simplifying assumptions, an optimal solution that can be easily implemented is obtaincd, The optimal solution is used in the simulation of a solar heating system using actual climatological data and the results are compared with that of on-off control. The result that not only the object function but, In some cases, also the solar energy retention rate the collector is increased. In is also found that the optimal control gets more advantageous as the solar insolation level gets lower, and also as tile cost of auxiliary heating fuel gets higher.