• Journal of Korea Water Resources Association
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• v.45 no.7
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• pp.675-684
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• 2012

Recently, a heavy rainfall under climate change causes the flood exceeded river's conveyance. Flood control methods under the limited river width are the increase of embankment, the construction of storage pockets and diversion channel, the dredging of river bed. Hwasun flood control reservoir of washland is designed as the storage pockets and the regulating gate for the control of water level. In this study, the propriety of design was investigated through hydraulic experiments for the circumstances to exclude the constant flood discharge during operation period. In the results, the over flow rate of side weir exceeded the flow of design and indicated to be able to discharge the designed flow in the regulating gate opened 1.1 m. The high velocity 7.1 m/s behind the gate has investigated to reduce under 3.3 m/s by the baffle block.

• Korean Journal of Agricultural Science
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• v.48 no.4
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• pp.935-944
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• 2021

It has been suggested that bisphenol A (BPA), a known endocrine disruptor, interferes with the endocrine system, causing reproductive dysfunction. Recently, BPA has been found in waste water due to incomplete sewage purification, possibly threatening health through its ingestion via tap water. In this study, young male mice (6 - 7 weeks old) were administered water containing BPA (50 mg·kg^-1) for four weeks, while control mice consumed water without BPA. Serum, epididymal spermatozoa and testicular sections were assessed after sacrificing the mice on day 28. No significant differences were obtained between the groups in the body, testis and seminal vesicle weights. However, the epididymal sperm motility and count levels were significantly reduced in BPA-fed mice. Significantly higher hepatotoxicity levels were also observed in mice ingesting BPA as compared to the control mice. The level of serum testosterone was reduced, and testicular sections revealed incomplete and irregular spermatogenesis in BPA-ingested mice. The sperm proteasomal-proteolytic activity level has been implicated in sperm function and is measured in motile spermatozoa using fluorometric substrates. High ubiquitin C-terminal hydrolase activity levels were observed in the control mice without BPA. During a mating trial, a low pregnancy rate (71.4%) was observed in females mated with males who had consumed BPA (100% in the control mice). Overall, BPA adversely affected spermatogenesis and quality, as indicated by decreased sperm motility, concentration and serum testosterone levels, resulting in reduced fertility competence.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2595-2609
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• 2024

This paper introduces a base isolation system-tuned mass damper inerter (BIS-TMDI) hybrid system to the AP1000 nuclear power plant (NPP), which reduces seismic damage potential of the NPP structure. The effects of fluid-structure interaction (FSI) caused by the passive containment cooling system water storage tank (PCCWST) on NPP's seismic performance are investigated. The FSI of water tank theoretical model is considered based on the Housner's model, and a series of time history analyses are performed to prove the rationality of the proposed model. Three single-objective optimization strategies are employed to minimize the relative displacement variance and absolute acceleration variance of the upper structure, as well as the filtered energy index (FEI). Furthermore, a multi-objective optimization strategy considering all these three indexes is proposed to obtain optimal parameters of vibration control. The influence of vibration control strategies on the relative deformation and acceleration of the upper structure is explored with various water level ratios. The analytical results indicate that the proposed BIS-TMDI strategy has significantly reduced the NPP structure's seismic response. The effectiveness of the vibration control strategy is influenced by the water level ratio, emphasizing the significance of designing an appropriate water level ratio to reduce NPP structure's seismic response.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.4
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• pp.72-78
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• 2009

This paper describes one of the ways how to decide the initial control parameters after the analog type control system is changed to digital control system. If the old control parameters were already known, the initial control parameters for initial operation could be decided easily. But sometimes, it is very difficult for the control system developer to decide initial parameters before plant machine starts up. In that case, if there is a big difference between initial parameters and optimal parameters, the whole plant itself can be in very dangerous conditions. Here is a very simple experimental method which can be very easy but useful to engineers.

• Korean Journal of Artificial Intelligence
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• v.1 no.1
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• pp.4-6
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• 2013

In the era of information society, IT industry has been developed very much. New technology has made appearance in citizens' lives. IOT (Internet of Things) has grown up the most rapidly in IT industry. Kevin Ashiton, MIT specialist, said, "Loading of FRIS and other sensors shall build Internet of things." Internet of things is said to let things have sensor and communication module and to exchange information and communicate each other. In this study, Internet of things has been applied to flowerpot to build automatic flowerpot control system that turns fan ON and supplies water depending upon temperature and moisture. Users are difficult to cognize temperature and humidity of flower pot correctly. In this study, an experiment obtained correct value of temperature and humidity to build control system. At the performance test of flower pot, commands turned ON depending upon temperature and humidity. Control system should be added to control water supply quantity and time objectively according to servo motor control. Purpose of further study was to control flower pot by remote system in connection with smart phone application. An application control can make not only temperature and humidity statistics but also server depending upon users' needs to turn fan ON and take actions and to control flower pot.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.109-114
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• 2009

The dominant heating system used in Korean residential apartment buildings is a hydronic radiant floor heating system, known as the Ondol system. The most common control strategy applied to this traditional hydronic radiant system is a simple on-off control that intermittently supplies "hot water of a fixed temperature" at a "constant flow rate" to each room. However, the current problems with the aforementioned control are as follows: (1) since the simple on-off control is usually based on a one point measured temperature (a signal from a thermostat installed in a living room) in each dwelling unit, heating energy use for unoccupied rooms as well as a difference in temperatures between spaces (master bedroom, living room, bedroom1, bedroom2) can occur occasionally. (2) the most widely used residential water splitter has static valves, and is thus not able to change the flow rate to each room depending on the space heating load. In other words, the ratio of flow rates to rooms is fixed after construction, resulting in over- or under-heating and an improper use of energy. The aim of this paper is therefore to investigate the differences in the system's performance between control strategies in terms of the flow rate control and sensor location. It is shown that energy savings of control strategies are strongly influenced by occupant schedule.

• Nuclear Engineering and Technology
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• v.52 no.11
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• pp.2522-2534
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• 2020

It is well known that the model of nuclear reactors features natural nonlinearity, and variable parameters during power tracking operation. In this paper, a disturbance observer-based adaptive sliding mode control (DOB-ASMC) strategy is proposed for power tracking of the pressurized-water reactor (PWR) in the presence of lumped disturbances. The nuclear reactor model is firstly established based on point-reactor kinetics equations with six delayed neutron groups. Then, a new sliding mode disturbance observer is designed to estimate the lumped disturbance, and its stability is discussed. On the basis of the developed DOB, an adaptive sliding mode control scheme is proposed, which is a combination of backstepping technique and integral sliding mode control approach. In addition, an adaptive law is introduced to enhance the robustness of a PWR with disturbances. The asymptotic stability of the overall control system is verified by Lyapunov stability theory. Simulation results are provided to demonstrate that the proposed DOB-ASMC strategy has better power tracking performance than conventional sliding mode controller and PID control method as well as conventional backstepping controller.

• Korean Journal of Biological Psychiatry
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• v.6 no.2
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• pp.240-245
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• 1999

Object : This study was designed to evaluate the effects of olanzapine on the schedule-induced polydipsia(SIP) which is one of animal model of obsessive-compulsive disorder in rats. We administered olanzapine as a serotonin and dopamine blocking agent, fluoxetine as a selective serotonin reuptake inhibitor, and haloperidol for the dopamine antagonist to rats which showed schedule-induced polydipsic behavior. Methods : Spraque-Dawley rats weighing 200-250gm were individually housed and maintained and allowed free access to water. The rats were placed on a restricted diet. To induce polydipsia, rats were placed in the cage where a pellet dispenser automatically dispensed 90mg pellets on a fixed-time 60 seconds(FT-60s) feeding schedule over 150 minute test session per day. Water was available at all times in the cage. After 4 weeks of daily exposure to the FT 60s feeding schedule, experimental rats met a predetermined criterion for polydipsic behavior(greater than 3 times of water per session on average). 5 groups of rats were administered olanzapine(3mg/kg, i.p), olanzapine(10mg/kg, i.p), fluoxetine(5mg/kg, i.p.), haloperidol(0.1mg/kg, i.p.), and vehicle(1cc/kg, i.p.) for 3 weeks. The rats were tested once a week to access schedule induced polydipsic behavior. Water bottles were weighed before and after the 150-minute test session. The chronic effects of administration of experimental drugs on schedule induced polydipsic behavior were analyzed with ANOVA and Scheffe test as a posthoc comparison. In order to measure water consumption in non-polydipsic food-deprived rats, a separate group of rats(N=8) were individually housed and given a single bolus(14.5gm) of food per day which maintained them at their average body weight. Results and Conclusion : The results were as follows ; 1) After 4 weeks of scheduled feeding procedure, the experimental group showed significant differences than the bolus control in the amount of water consumption as compared with their average water intakes for 4 weeks. At the same periods, there were no differences between the experimental group and the bolus control in the body weight. 2) The fluoxetine group showed significant decrease in the amount of water intake over the 3 weeks of drug treatment as compared with their average amount of polydipsic water intakes. The olanzapine 3mg group showed significant decrease in the amount of water intake at 3rd weeks of drug treatment as compared with their average amount of polydipsic water intakes. The olanzapine 10mg group showed significant decrease in the amount of water intake at 2nd and 3rd weeks of drug treatment as compared with their average amount of polydipsic water intakes. However, the haloperidol group and the vehicle control group showed no changes of amounts of water intake for 3 weeks of treatment as compared with their average amount of polydipsic water intakes. 3) The fluoxetine group showed significantly lower amounts of water intake than the haloperidol group at 2nd weeks of drug treatment. And also the fluoxetine group showed significantly lower amounts of water intake than the haloperidol group and the vehicle control at 3rd weeks of drug treatment. The olanzapine 3mg group and the olanzapine 10mg group showed significantly lower amounts of water intake than the haloperidol group and the vehicle control at 3rd weeks of drug treatment. Above findings suggest that the fixed time feeding procedure for schedule-induced polydipsia as an animal model of obsessive compulsive disorder was effective to the evaluation of pharmacological challenge study. The authors assume that the serotonin hypothesis and the serotonin-dopamine interaction hypothesis are preferred to the dopamine hypothesis in the biological etiology of obsessive-compulsive disorder.

• Journal of Nutrition and Health
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• v.39 no.6
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• pp.513-519
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• 2006

The effects of fractions of ethanol extract of Benincasa hispida (wax gourd) on lipid levels and lipid peroxidation in streptozotocin (STZ) induced diabetic rats were examined. Sprague-Dawley rats were induced diabetes mellitus by STZ injection (45 mg/kg) into the tail vein and were divided into 5 groups: normal, STZ-control, three experimental diabetic groups [chloroform $(CHCl_3)$ fraction group, butanol (BuOH) fraction group, and water fraction group]. Fractions of ethanol extract of Benincasa hispida were administered orally into the diabetic rats for 14 days. The liver glycogen levels of $CHCl_3$ fraction group and the muscle glycogen levels of BuOH and water fraction groups were significantly higher than that of STZ-control group. Pancreas protein levels of BuOH and water fraction groups were significantly higher than that of STZ-control group. The liver cholesterol level of BuOH and water fraction groups were significantly lower when compared with the STZ-control group. The level of liver triglyceride in BuOH and water fraction groups were significantly higher than that of STZ-control group. Malondialdehyde (MDA) levels in liver of normal and diabetic groups were not significantly different. In the pancreas, the MDA levels of BuOH and water fraction group were significantly lower than that of STZ-control group. The results suggested that the supplementation of the BuOH and water fractions of Benincasa hispida extract could be beneficial for the diabetic complications and damages from the lipid peroxidation.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.338-341
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• 2011

Water usage for cleaning the toilet bowl accounts for 27% of the total water usage. Water-saving valve that can select the amount of water for cleaning toilet bowl can be reduced expenditure. After installing water-saving valve, analysed the economic effects. Water-saving valves compared with flush valves, and researched the amount of water usage. Then analyzed fort he economic effects. Water-saving valve was used 5.6 ${\ell}/time$ for cleaning toilet bowl. In contrast, flush valve was consumed 8.4 ${\ell}/time$. Water-saving valve's water-saving rate was 33.3%. The initial payback period for Water-saving valve was 459.5 days. By a small investment in water saving valve, the economic benefits can be obtained.