• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.381-388
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• 2018

Microbubbles oxygen transfer to water was simulated based on experimental results obtained from the bubbles generation operated under varying liquid supply velocity to the multi-step orifices of the generator. It had been known that liquid supply velocity and bubble size are inversely related. In the oxygen transfer, a non-steady state was assumed and the pseudo stagnation caused the slow movement of bubbles from the bottom to the water surface. Two parameters were considered for the simulation: They represent a factor to correct the pseudo stagnation state and a scale which represented the amount of bubbles in supply versus time. The sum of absolute error determined by fitting regression to the experimental results was comparable to that of the American Society of Civil Engineers (ASCE) model, which is based on concentration differential as the driving force. Hence, considering the bubbles formation factors, the simulation process has the potential to be easily used for applications by introducing two parameters in the assumptions. Compared with the ASCE model, the simulation method reproduced the experimental results well by detailed conditions.

• Land and Housing Review
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• v.7 no.2
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• pp.67-75
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• 2016

This research suggests improvement strategies for the problems of 'public housing supplied through the purchase of existing house' by understanding the situation of supply to lowest income class in Seoul where there are many demands. Due to the heavy housing expenditure burden, in spite of the fact that the needs for affordable housings are increasing, the number of 'public housing supplied through the purchase of existing house' which has been supplied to Seoul by LH & SH has decreased since 2009. It is caused by the low standard purchasing price set by government especially Seoul. Since 'the public housing supplied through the purchase of existing house' is targeted for indigenous inhabitants, different supply stocks among different regions cause equity problem. Generally regions with low income class are in short supply, on the contrary the supply is especially concentrated specific regions in outskirts of Seoul. The main reason of such new supply stagnation and regional concentration is the low standard purchasing price. Therefore, it is necessary to increase the government's standard price according to the actual transaction price. Also it is needed to associate actual transaction price's increasing rate with the government's standard price. The housing supply based on demands must be established. In addition, the provision of 'public housing supplied through the purchase of existing house' should be expanded to low-middle income inhabitants and low income youth in the regions where the supply of the affordable housing excess demands.

• Journal of Haehwa Medicine
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• v.9 no.2
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• pp.241-250
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• 2001

A study on relation of angiogenesis and blood stagnation in cancer was done, and the results were as follows. 1. Angiogenesis is a sequence of vascular proliferation and accomplished by regulation of anti-angiogenesis factor and indicating factor. These factors are secreted in the course of blood coagulation, inflammation, and regeneration. 2. Angiogenesis in cancer is a important action in growth of tumor and metastasis because it supply oxygen and nutrition. 3. The complicated processes, for example, platelet coagulation, action of coagulator factor & dissolution factor and interaction of variety factors are related to blood stasis and promoting blood circulation to remove blood stasis in oriental medicine. 4. Promoting blood circulation to remove blood stasis is expected to suppress angiogenesis, and we expect advanced study will be accomplished in future.

• Korean Journal of Construction Engineering and Management
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• v.15 no.5
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• pp.147-159
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• 2014

After 2008 global financial crisis, Korean housing market has experienced stagnation. So it caused housing market problems like housing price reduction, rising rent cost and so on. For housing market normalization government announced policies but Korean housing market didn't recover from stagnation. So, to understand why Korean housing market couldn't overcome the recession and why the policies didn't be effective, this research analyzed housing market participants (home owner, housing demand) based on the law of supply and demand and the psychological effect on their transaction intention based on behavioral economics(behavioral finance). Based on the analysis this research tested the effectiveness of announced policies using System Dynamics. The result showed that the amount of transaction and mortgage loan was influenced by the length of time to draft policies.

• Journal of the Korean Institute of Rural Architecture
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• v.3 no.3
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• pp.57-67
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• 2001

The evolution of multi-family housing in Cheongju can be divided by four stages which are a introduction period from 1972 to 1980, a popularization period from 1981 to 1989, a expansion period from 1990 to 1997, and a stagnation period after 1998. In the introduction period, the multi-family housings were mainly low-rise buildings because a government policy which focused on extension of the apartments for the low-income influenced multi-family housing constructions. During the popularization period, the multi-family housings were still low-rise but houses in various sizes were introduced. That was because the Housing Site Developments were started and private companies' participations followed them increasingly. As a result of vigorous participations of private companies and massive developments of housing sites, the multi-family housings in the expansion period started to show constructions of complex and trends of high density and high rising. Finally, in the stagnation period, a rate of the supply of the small houses, whose size was below $60m^2$ of exclusive, area was increased and extreme high-rise apartments emerged. High rising and density were the mainstream of the construction concepts. During this period, the growth of multi-family housing marked low. The reason was that a downturn in economy led private companies to shrink their constructions.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.843-848
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• 2017

Metal exposed to high temperature/high pressure/oxidizer-rich environment may cause rapid oxidation(ignition and combustion). In this study, a DC power supply test system that controls the temperature of specimen by supplying power to the specimen was constructed and after simulating the high temperature/stagnation/oxidizer-rich environment, the metal oxidation and ignition of STS series metal materials were evaluated. As a result, we was confirmed that the deformation (discoloration) of the selected material, the change in the surface roughness and the peeling of the metal surface were observed, and that the weight and the specimen thickness were changed. The most oxidized specimen was STS 304 and the less oxidized specimen was XM-19.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.180-182
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• 1992

In spite of recent stagnation, the rate of electric consumption has highly grown in accordance with a high cultural livings, Also, a usage of electric energy is growing with development of multi-information society. To make the matter worse, hard work of highest order is required because distribution system are widely spread and complex. And consummers demand for the electricity of good quality and it is obstracle to be not able to train related technitian for maintenance without an interruption of electric power. It is sure the counterplan of uninterruption of electric power is very necessary. In this paper, considering the working circumstances, we presented the necessity of work method, the effects and the future prospect for uninterruption power supply.

• Journal of Environmental Health Sciences
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• v.36 no.5
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• pp.402-410
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• 2010

The objectives of this study were to evaluate the air quality surrounding an indoor swimming pool, to estimate the cancer risk based on the airborne exposure to trihalomethanes (THMs), and to examine the ventilation efficiency by Computational Fluid Dynamics (CFD). Chlorine and THMs were measured poolside, and in the staff room and reception area. The indoor swimming pool was modeled using the Airpak program, with ventilation drawings and actual survey data. Temperature, flow and mean age of the air were analyzed. Levels of chlorine poolside, and in the staff room, and reception area were $203\;{\mu}g/m^3$, $5\;{\mu}g/m^3$, and $10\;{\mu}g/m^3$, respectively. Chloroform was the dominant THM in all sampling sites and mean concentrations were $16.30\;{\mu}g/m^3$, $0.51\;{\mu}g/m^3$, and $0.06\;{\mu}g/m^3$ poolside, in the staff room and reception area, respectively. Bromodichloromethane and Dibromochloromethane levels were respectively estimated as $10.3\;{\mu}g/m^3$ and $1.7\;{\mu}g/m^3$ poolside, $1.3\;{\mu}g/m^3$ and $0.1\;{\mu}g/m^3$ in the staff room, and were not detected in the reception area. The cancer risks from inhalation exposure to THMs were estimated between $3.37{\times}10^{-7}$ and $1.84{\times}10^{-5}$. A short circulation phenomenon was observed from the supply air vents to the exhaust air vents located in the ceiling. A high temperature layer was formed within one meter of the ceiling, and a low temperature layer was formed under this layer due to the low velocity and high temperature of the supply air, and the improper locations of the supply air vents and exhaust air vents. The stagnation was evident at the above adult pool and the mean age of the air was 22 minutes. Disinfection by-products in the indoor swimming pool were present in higher concentrations than in the outdoor air. In order to increase the removal of pollutants, adjustment was required of the supply air volume and the supply/exhaust position.

• Journal of Urban Science
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• v.6 no.2
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• pp.29-34
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• 2017

Although the supply of public parking lots in major cities is steadily increasing, there is still a shortage of parking spaces that take into account the characteristics of actual available parking spaces. These parking problems are caused by conflicts between users, illegal occupation and privatization of roads, interference with traffic roads, and business stagnation in commercial areas and illegal parking problems. In addition, despite various parking demand management policies and continuous supply of public parking facilities, the solution to the parking problem is uneasy due to increased construction costs and changes in social conditions. In order to solve this problem, it was judged that it would be necessary to utilize the existing public parking lots efficiently. Therefore, we collect the variables expected to affect the turnover, and use multiple regression models. The results are summarized as follows. Firstly, public parking lots can be classified into four types using utilization rate and turnover rate. Secondly, influencing factors are found including index of public transportation usage convenience, index of illegal parking, and land use characteristics in central commercial district. Thirdly, it was shown that there was little impact by the size of public parking lots, separation distance to subway distance, separation distance to bus stops, transfer zone, residential zone, and second-rated lots by parking costs. Finally, it is found that public parking lots can be improved by proving accessibility of public transit, enforcement of illegal parking, active approaches supporting public parking lots. It is also recommended that public parking cost rating system based mainly on land use characteristics should be remedied and rearranged.

• Convergence Security Journal
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• v.19 no.5
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• pp.3-9
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• 2019

The importance of Industrial Security is continuously growing along with the rapid development of convergence technologies. Accordingly, it is expected for the gap between the supply and demand of industrial security professional personnel to grow every year. In order to reduce the supply and demand of industrial security, it is important to not only train professional qualifications but at the same time, secure a professional qualification acquisitor. In this regard, South Korea has introduced the Industrial Security Expert qualification as a non-governmental qualifications ince 2010. From 2017, promoted as nation-certified qualification and has supported activities as expert in industrials ecurity field. However, it is reality that Industrial Security Expert qualification has not yet to be recognized as professional qualification in the field of industry, have low rate of utilization as academic research is also shown the sign of stagnation. Based on these background, this research set goal in deducing a activation method for industrial security professional qualification concentrating on Industrial Security Expert qualification. The analysis on operation condition of Industrial Security Expert qualification and related precedent research was conducted and raised four types of activation method, which are organizational aspect, certification system improvement and operation aspect, certification acquisitors' utilization aspect and professionalism enhancement aspect.