• Journal of ILASS-Korea
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• v.25 no.4
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• pp.162-169
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• 2020

The worldwide focus on reducing the emissions, fuel and lubricant consumption in T-GDI engines is leading engineers to consider the crankcase ventilation and oil mist separation system as an important means of control. In today's passenger cars, the oil mist separation systems mainly use the inertia effect (e.g. labyrinth, cyclone etc.). Therefore, this study has investigated high efficiency cylinder head-integrated oil-mist separator by using a compact multi-impactor type oil mist separator system to ensure adequate oil mist separation performance. For this purpose, engine dynamometer testing with oil particle efficiency measurement equipment and 3D two-phase flow simulation have been performed for various engine operating conditions. Tests with an actual engine on a dynamometer showed oil aerosol particle size distributions varied depending on operating conditions. For instance, high rpm and load increases bot only blow-by gases but the amount of small size oil droplets. Submicron-sized particles (less than 0.5 ㎛) were also observed. It is also found that the impactor type separator is able to separate nearly no droplets of diameter lower than 3 ㎛. CFD results showed that the complex aerodynamics processes that lead to strong impingement and break-up can strip out large droplets and generate more small size droplets.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1649-1654
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• 2021

In this paper, we introduce a regularization of long short-term memory (LSTM) based fall detection system using TensorFlow that can detect falls that can occur in the elderly. Fall detection uses data from a 3-axis acceleration sensor attached to the body of an elderly person and learns about a total of 7 behavior patterns, each of which is a pattern that occurs in daily life, and the remaining 3 are patterns for falls. During training, a normalization process is performed to effectively reduce the loss function, and the normalization performs a maximum-minimum normalization for data and a L2 regularization for the loss function. The optimal regularization conditions of LSTM using several falling parameters obtained from the 3-axis accelerometer is explained. When normalization and regularization rate λ for sum vector magnitude (SVM) are 127 and 0.00015, respectively, the best sensitivity, specificity, and accuracy are 98.4, 94.8, and 96.9%, respectively.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.54-55
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• 2015

Increase of impervious areas due to expansion of housing area, commercial and business building of urban is resulting in property change of stormwater runoff. Also, rapid urbanization and heavy rain due to climate change lead to urban flood and debris flow damage. In 2010 and 2011, Seoul had experienced shocking flooding damages by heavy rain. All these have led to increased interest in applying LID and decentralized rainwater management as a means of urban hydrologic cycle restoration and Natural Disaster Prevention such as flooding and so on. Urban development is a cause of expansion of impervious area. It reduces infiltration of rain water and may increase runoff volume from storms. Low Impact Development (LID) methods is to mimic the predevelopment site hydrology by using site design techniques that store, infiltrate, evaporate, detain runoff, and reduction flooding. Use of these techniques helps to reduce off-site runoff and ensure adequate groundwater recharge. The contents of this paper include a hydrologic analysis on a site and an evaluation of flooding reduction effect of LID practice facilities planned on the site. The region of this Case study is LID Rainwater Management Demonstration District in A-new town and P-new town, Korea. LID Practice facilities were designed on the area of rainwater management demonstration district in new town. We performed analysis of reduction effect about flood discharge. SWMM5 has been developed as a model to analyze the hydrologic impacts of LID facilities. For this study, we used weather data for around 38 years from January 1973 to August 2014 collected from the new town City Observatory near the district. Using the weather data, we performed continuous simulation of urban runoff in order to analyze impacts on the Stream from the development of the district and the installation of LID facilities. This is a new approach to stormwater management system which is different from existing end-of-pipe type management system. We suggest that LID should be discussed as a efficient method of urban disasters and climate change control in future land use, sewer and stormwater management planning.

• Wind and Structures
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• v.38 no.2
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• pp.129-146
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• 2024

Aiming at the problem of non-stationary wind field simulation of downbursts, a non-stationary down-burst generation system was designed by adding a nozzle and program control valve to the inlet of the original wall jet model. The computational fluid dynamics (CFD) method was used to simulate the downburst. Firstly, the two-dimensional (2D) model was used to study the outflow situation, and the database of working conditions was formed. Then the combined superposition of working conditions was carried out to simulate the full-scale measured downburst. The three-dimensional (3D) large eddy simulation (LES) was used for further verification based on this superposition condition. Finally, the wind tunnel test is used to further verify. The results show that after the valve is opened, the wind ve-locity at low altitude increases rapidly, then stays stable, and the wind velocity at each point fluctuates. The velocity of the 2D model matches the wind velocity trend of the measured downburst well. The 3D model matches the measured downburst flow in terms of wind velocity and pulsation characteris-tics. The time-varying mean wind velocity of the wind tunnel test is in better agreement with the meas-ured time-varying mean wind velocity of the downburst. The power spectrum of fluctuating wind ve-locity at different vertical heights for the test condition also agrees well with the von Karman spectrum, and conforms to the "-5/3" law. The vertical profile of the maximum time-varying average wind veloci-ty obtained from the test shows the basic characteristics of the typical wind profile of the downburst. The effectiveness of the downburst generation system is verified.

• The Korean Journal of Pharmacology
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• v.21 no.2
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• pp.119-127
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• 1985

The renal function is under regulatory influence of the central nervous system, mainly through activation of sympathetic nerve to the kidney, and it was recently reported that clonidine, an agonist to ${\alpha}_2$-adrenoceptors, induces diuresis and natriuresis when injected directly into a lateral ventricle of the rabbit brain (i.c.v.). This study was undertaken, therefore, to obtain further information as to the role of the central ${\alpha}_2$-adrenoceptors in regulating renal function, by observing the effects of i.c.v. yohimbine, a specific antagonist of adrenoceptors of ${\alpha}_2$-type, on the rabbit renal function, and to elucidate the mechanism involved in it. With 10 ${\mu}g/kg$ i.c.v. of yohimbine sodium excretion transiently increased along with increasing tendency of urine flow, renal plasma flow and glomerular filtration rate. These responses decreased with increasing doses. With 100 and 300 ${\mu}g/kg$ i.c.v. marked antidiuresis and antinatriuresis as well as profound decreases of renal perfusion and glomerular filtration were noted. Systemic blood pressure transiently increased. In reserpinized rabbits, 100 ${\mu}g/kg$ yohimbine i.c.v. did not produce any significant changes in urine flow, sodium excretion as well as in renal hemodynamics. The pressor response was also abolished. In preparations in which one kidney was denervated and the other left intact as control, i.c.v. yohimbine elicited typical antidiuretic antinatriuretic response in the innervated control kidney, whereas the denervated experimental kidney responded with marked diuresis and increases in excretory rates of sodium and potassium and in osmolar clearance in spite of absence of increased filtration and perfusion . Systemic blood pressure responded as in the normal rabbits. These observations indicate that i.c.v. yohimbine affects renal function in dual ways in opposite directions, the first being the antidiuretic antinatriuretic effects which results from decreased renal perfusion and glomerular filtration due to sympathetic activation and which is predominantly expressed in the normal rabbits, and the second less apparent effect being the diuretic and natriuretic action which is not mediated by nerve pathway but brought about by some humoral mechanism and which is effected by decreased sodium reabsorption in the tubules, possibly of the proximal portion.

• Journal of Acupuncture Research
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• v.17 no.1
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• pp.251-286
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• 2000

To study the effects of anti-cancer, anti-metastasis and immune response improvement of aqua-acupuncture with Cistanches Herba infusion solution, we used Cistanches Herba infusion solution(taken by water-alcohol method) put into Chung-wan(CV12) and Chok-Samni(S36) of BALB/c or C57BL/6 which are corresponding to human body. We observed the cytotoxicity, the effect on the expression of MMP-9 gene, the ability to control cancer cell proliferation, change of body weight, surviving number, MST, ILS, changes in amount of WBC, RBC, PLT, total protein, creatinine, glucose and LDH, weight of spleen, number of pulmonary colony, histological analysis on tissue metastasis of lung and liver, splenic cell proliferation, the expression of cytokine gene, the number of $CD4^+$, $CD8^+$, $CD19^+$ and NK cell, and concluded like this. The results were obtained as follows : 1. The cytotoxicity about B16-F10 cell line of $2^0$, $2^{-1}$, $2^{-2}$, $2^{-5}$ diluent groups in Cistanches Herba infusion solution treatment was inhibited significantly, compared with control group. 2. The cytotoxicity about HT1080 cell line of $2^0$, $2^{-1}$, $2^{-2}$, $2^{-3}$, $2^{-5}$, $2^{-8}$ diluent groups in Cistanches Herba infusion solution treatment was inhibited significantly, compared with control group. 3. The effect on expression of MMP-9 gene was decreased in all the sample groups, compared with control group. 4. The effect on the control-ability on the cancer cell proliferation showed cytotooicity significantly in $2^0$, $2^{-1}$, $2^{-2}$, $2^{-3}$, $2^{-4}$, $2^{-5}$ diluent groups. 5. S-180 cancer cell line transplants in BALB/c mice were inhibited significantly in weight increase in all the sample groups, compared with control group. The surviving number increased in almost sample groups, except one group put into Chok-Samni(S36) with 20% Cistanches Herba infusion solution treatment group that showed same number of the control group. 6. S-180 cancer cell line transplants in BALB/c mice showed high MST and ILS significantly in almost sample groups, compared with control group. But one group put into Chok-Samni(S36) with 20% Cistanches Herba infusion solution treatment group showed low MST and ILS than control group. 7. The sample group injected in vein with B16-F10 cancer cell line in C57BL/6 mice showed increased ILS compared with control group significantly in anti-metastasis test. 8. The sample group injected in vein with B16-F10 cancer cell line in C57BL/6 mice were increased significantly in the number of WBC and glucose, and decreased significantly in the amount of LDH, compared with control group. However, there's no significant increase or decrease in number of RBC, PLT, total protein and creatinine. 9. We couldn't find any significant relation in spleen weight of the sample group. 10. In pulmonary colony, sample group was decreased significantly, compared with control group. 11. Histological analysis of sample group inhivited compared with that of control group in both of lung and liver. 12. In immune system, all the sample groups showed having more relevancy to the effect on splenic cell proliferation than normal group. 13. The effect on cytokine gene expression of all the sample groups were increased than control group. 14. In flow cytometry there's no significant relation in number of $CD8^+$, $CD19^+$ cell, however, the number of $CD4^+$ cell and NK cell in sample groups were increased than in control group. Above the results showed that aqua-acupuncture of Cistanches Herba infusion solution has effects of anti-cancer, anti-metastasis and immune response improvement.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.6
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• pp.427-446
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• 2008

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2006 has been accomplished. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro heat exchanger and siphon cooling device using nano-fluid. Traditional CFD and flow visualization methods were still popular and widely used in research and development. Studies about diffusers and compressors were performed in fluid machinery. Characteristics of flow and heat transfer and piping optimization were studied in piping systems. (2) The papers on heat transfer have been categorized into heat transfer characteristics, heat exchangers, heat pipes, and two-phase heat transfer. The topics on heat transfer characteristics in general include thermal transport in a cryo-chamber, a LCD panel, a dryer, and heat generating electronics. Heat exchangers investigated include pin-tube type, plate type, ventilation air-to-air type, and heat transfer enhancing tubes. The research on a reversible loop heat pipe, the influence of NCG charging mass on heat transport capacity, and the chilling start-up characteristics in a heat pipe were reported. In two-phase heat transfer area, the studies on frost growth, ice slurry formation and liquid spray cooling were presented. The studies on the boiling of R-290 and the application of carbon nanotubes to enhance boiling were noticeable in this research area. (3) Many studies on refrigeration and air conditioning systems were presented on the practical issues of the performance and reliability enhancement. The air conditioning system with multi indoor units caught attention in several research works. The issues on the refrigerant charge and the control algorithm were treated. The systems with alternative refrigerants were also studied. Carbon dioxide, hydrocarbons and their mixtures were considered and the heat transfer correlations were proposed. (4) Due to high oil prices, energy consumption have been attentioned in mechanical building systems. Research works have been reviewed in this field by grouping into the research on heat and cold sources, air conditioning and cleaning research, ventilation and fire research including tunnel ventilation, and piping system research. The papers involve the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies on indoor air quality took a great portion in the field of building environments. Various other subjects such as indoor thermal comfort were also investigated through computer simulation, case study, and field experiment. Studies on energy include not only optimization study and economic analysis of building equipments but also usability of renewable energy in geothermal and solar systems.

• Journal of Acupuncture Research
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• v.17 no.1
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• pp.189-219
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• 2000

To study the effects of anti-cancer, anti-metastasis and immune response improvement effects of aqua-acupuncture with Rubi Fructus infusion solution, we used Rubi Fructus infusion solution(taken by water-alcohol method) put into Chung-wan (CV12) and Chok-Samni(ST36) of BALB/c or C57BL/6 which are corresponding to humanbody. We observed the cytotoxicity, the effect on the expression of MMP-9 gene, the ability to control cancer cell proliferation, change of body weight, surviving number, median surviving time, increase of life span, changes in amount of leukocyte, erythrocyte, platelet, total protein, creatinine, glucose and LDH, weight of spleen, number of pulmonary colony, histological analysis on tissue metastasis of lung and liver, splenic cell proliferation, the expression of cytokine gene, the number of $CD4^+$, $CD8^+$, $CD19^+$ and NK cell, and concluded like this. The results were obtained as follows : 1. Effects of Anti-cancer 1) The cytotoxicity about B16-F10 cell line of $2^0$, $2^{-1}$, $2^{-2}$, $2^{-3}$, $2^{-5}$, $2^{-6}$, $2^{-7}$, $2^{-8}$ diluent groups in Rubi Fructus infusion solution treatment was inhibited significantly, compared with control group. 2) The cytotoxicity about HT1080 cell line of $2^0{\sim}2^{-8}$ diluent groups in Rubi Fructus infusion solution treatment was inhibited significantly, compared with control group. 3) The effect on expression of MMP-9 gene was inhibited significantly in all the sample groups, compared with control group. 4) The effect on the control-ability on the cancer cell proliferation showed cytotoxicity significantly in $2^0$, $2^{-1}$, $2^{-2}$, $2^{-3}$, $2^{-4}$, $2^{-5}$, $2^{-6}$, $2^{-7}$, diluent groups. 2. Effects of Anti-metastasis 1) S-180 cancer cell line transplants in BALB/c mice were inhibited significantly in weight increase in all the sample groups, compared with control group. The surviving number increased in almost sample groups, except one group put into Chok-Samni(ST36) with 20% Rubi Fructus infusion solution treatment group that showed same number of the control group. 2) S-180 cancer cell line transplants in BALB/c mice showed high MST significantly in almost sample groups, compared with control group. But one group put into Chok-Samni(ST36) with 20% Rubi Fructus infusion solution showed low MST than control group. 3) The group injected in vein with B16-F10 cancer cell line in C57BL/6 mice showed increased ILS than control group significantly in anti-metastasis test. 3. Effects of Immune response improvement 1) The group injected in vein with B16-F10 cancer cell line in C57BL/6 mice were increased significantly in the number of leukocyte and glucose, and decreased significantly in the amount of platelet and LDH, compared with control group. However, there's no significant increase or decrease in number of erythrocyte, total protein and creatinine. 2) We couldn't find any significant relation in spleen weight of the sample group. 3) In pulmonary colony, sample group was decreased significantly, compared with control group. 4) Histological analysis of sample group inhivited compared with that of control group in both of lung and liver. 5) In immune system, all the sample groups showed having more relevancy to the effect on splenic cell proliferation than normal group. 6) Cytokine gene increased in almost sample groups, except one group treated with $50{\mu}g/m{\ell}$ Rubi Fructus infusion solution on IL-12. 7) In flow cytometry there's no significant relation in number of $CD8^+$ cell, however, the number of $CD4^+$, $CD19^+$ cell and NK cell in sample group had more relation than in control group. Above the results showed that aqua-acupuncture of Rubi Fructus solution has effects of anti-cancer, and-metastasis and immune response improvement.

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.581-586
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• 2014

Main objects for wastewater treatment operation are to maintain effluent water quality and minimize operation cost. However, the optimal operation is difficult because of the change of influent flow rate and concentrations, the nonlinear dynamics of microbiology growth rate and other environmental factors. Therefore, many wastewater treatment plants are operated for much more redundant oxygen or chemical dosing than the necessary. In this study, the optimal control scheme for dissolved oxygen (DO) is suggested to prevent over-aeration and the reduction of the electric cost in plant operation while maintaining the dissolved oxygen (DO) concentration for the metabolism of microorganisms in oxic reactor. The oxygen uptake rate (OUR) is real-time measured for the identification of influent characterization and the identification of microorganisms' oxygen requirement in oxic reactor. Optimal DO set-point needed for the micro-organism is suggested based on real-time measurement of oxygen uptake of micro-organism and the control of air blower. Therefore, both stable effluent quality and minimization of electric cost are satisfied with a suggested optimal set-point decision system by providing the necessary oxygen supply requirement to the micro-organisms coping with the variations of influent loading.

• Clean Technology
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• v.21 no.3
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• pp.191-199
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• 2015

The SO_x emission from the ship diesel engines will do a negative influence to the human health and the environment. To reduce the negative environmental effect of the SO_x emission caused by the high traffic of ship movements, the SECA (SO_x emission control area) has been set on several province around world to carry out the severe emissions control and to meet the emissions control standard. To cut down the SO_x emission from the ships, the wet type scrubber is being used widely. In this work, we prepared a numerical model to simulate the spray type scrubber to study the motion of liquid droplets in the flow of the scrubber. For the analysis, the CFD (computational fluid dynamics) method was adopted. As a special topic of the study, we designed the wave plate type of mist eliminator to check the carry over of the uncontrolled water droplet to the exhaust. Numerical analysis is divided into two stages. At the first stage, the analysis was done on the basic scrubber without the mist eliminator, and then the second stage of analysis was done on the scrubber with the mist eliminator on several condition to check and compare with the basic scrubber. On the condition of the basic scrubber, 42.0% of the distributed water droplets were carried over to the exhaust. But by adding the designed droplet eliminator at the exhaust of the scrubber, only 3.4% of the distributed water droplets supplied to the scrubber was emitted to the atmosphere.