• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.75-82
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• 2008

Control of dam gates is a complex, nonlinear, and non-stationary control process and is significantly affected by hydrological conditions which are not predictable beforehand. In this paper, we proposed control methods based on a fuzzy inference method for the operation of dam gates. The proposed methods are not only suitable for controlling gates but also able to maintain target water level in order to prepare a draught, and able to control the amount of the outfow from a reservoir in order to prevent floods in lower areas of a river. In the proposed methods, we used the dynamic fuzzy inference method that membership functions can be varied by changing environment conditions for keeping up the target water level instead of conventional static fuzzy inference methods, and used additional fuzzy rules and membership functions for restricting the amount of the outflow. Simulation results demonstrated that the proposed methods produce an efficient solution for both of maintaining target water level defined beforehand and controlling the amount of the outflow.

• Journal of Korea Water Resources Association
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• v.32 no.6
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• pp.685-695
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• 1999

On the premise of flood control procedure, flood forecasting-warning, system(FFWS) is one of actions for disaster prevention. It makes public announcements for flood situations timely in order to mitigate damage from floodings. Multi-purpose dam which has flood control storage plays an important role in river basin at flood time. In FFWS, it is reservoir operation module that is related to reservoir operation of multi-purpose dam. This study considers the current conditions and problems in reservoir operation module of FFWS in Han River and improves reservoir operation module under limited research scope. As results, additional reservoir operation modules such as Technical ROM(Reservoir Operation Method) and ARD(Approved Release Discharge) ROM were built in FFWS. Using these newly built reservoir operation modules. Han River Flood Control Office will plan and work for flood control and flood forecasting. Firstly, it may plan for flood control by Technical ROM which is deterministic simulation model, and work for final flood control and flood forecasting by ARD ROM according to approved release discharge afterward.

• Journal of Environmental Health Sciences
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• v.23 no.3
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• pp.56-65
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• 1997

Chemical analysis, statistical analysis and geochemical study were carried out to investigate the influence of the geology on the chemical characferistics of the mineral water in Taegu area. A simple comparision between the chemical components of the mineral water and their bedrocks indicates that the bedrock types in the catchmerit area control the chemical characteristics of the surface water. However more objective evidences for the mineral water-bedrock relationship come from the statistical analyses(cluster analysis and factor analysis). The results of the statistical analyses suggest that the bedrock type factor explains the data variation seven times as much as pollution does, which evidently indicates that the bedrock in the study area mainly control the mineral water chemistries. The results of comparision of the statistical analyses results with the mineral weathering reactions and mineral stability diagrams can be summarized as follows: 1. Plagioclase weathering to kaolinite provides SiO$_2$ , Ca$^{2+}$ and Na$^+$, and muscovite weathering to kaolinite provides K$^+$, and amphibole and mica minerals weathering to kaolinite provides F to the mineral water. Most of Ca$^{2+}$ and Mg$^{2+}$ in the mineral water are the products of carbonate mineral dissolution. SO$_4^{2-}$ may be the byproduct of sulfide oxidation. 2. The weatering of silicate mineral produces Ca-rich smectite and kaolinite, but Ca-rich smectite is unstable and will be transformed to more stable kaolinite because of the continuous dilution of the mineral water by precipitation. By Hashimoto's Mineral Balance Index, S-10 and S-12 mineral spring water were evaluated tasty and healthy water, S-9 and S-11 mineral spring water were evaluated tasty water and S-7, S-8 and S-13 mineral spring water were evaluated healthy water.

• Corrosion Science and Technology
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• v.17 no.1
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• pp.12-19
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• 2018

Langelier Index (LI) is used as a tap water corrosiveness index. Residual chlorine in tap water induces corrosion inside water pipes. This study takes a deeper look into the effect of residual chlorine in water pipes. Comparison between tap waters of Y and K water treatment plant (WTP) shows that the LI index of K WTP is lower than that of Y. However, the corrosion rate of Y WTP is higher than that of K WTP. This means that the higher the concentration of residual chlorine in tap water, the higher the corrosion rate of pipe materials. When calcium hydroxide was added to tap water, the corrosiveness index was improved and thus the corrosion rate reduced. It is possible to increase the disinfection efficiency by increasing the duration of residual chlorine and suppressing the rust generation of water pipes and to supply minerals. A guideline for corrosion control with residual chlorine should be set up. The effects of residual chlorine should be included in the corrosiveness index of tap water.

• Mycobiology
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• v.42 no.4
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• pp.331-338
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• 2014

To examine the effects of water stress and Cenangium ferruginosum (CF) on the fungal endophytic community of needles of Pinus koraiensis (PK), fungal endophytes isolated from the needles of 5-year-old PK seedlings were compared before and after exposure to water stress conditions and artificial inoculation with CF ascospores. Artificial CF inoculation was successfully confirmed using PCR with CF-specific primers (CfF and CfR). For comparison of the degree of water deficit in water-stressed and control groups of PK seedlings infected with CF, the water saturation deficit and water potential were measured. Lower water potential estimates were found in the water-stressed seedlings than in the control group. The fungal endophytes isolated from the second-year needles of non-water-stressed seedlings before and after CF inoculation revealed that primary saprobes were approximately 30% and 71.7%, respectively, and the remaining endophytes were rot fungi or pathogens. Sixty days after CF inoculation, diverse fungal endophytes in the first-year needles were isolated from the water-stressed seedlings. However, some fungal endophytes isolated from the non-water-stressed seedlings were also identified. Fungal endophytes in the second-year needles of the water-stressed and non-water-stressed seedlings were approximately 8% and 71.7% of saprobes, respectively, and the remaining endophytes were rot fungi or pathogens. On the basis of the results, we conclude that water deficit and CF can have an effect on fungal endophytic communities in the needles of PK seedlings.

• Journal of Korean Society of Water and Wastewater
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• v.36 no.5
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• pp.261-273
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• 2022

In this study, we collect water control valves that have had accidents due to existing cracks, etc. are collected, and propose investigation items for strengthening the valve structural safety evaluation through a series of analyzes from valve specifications to physicochemical properties are proposed. The results of this study are as follows. First, there was a large variation in the thickness of the body or flange of the valves to be investigated, which is considered to be very important factor, because it may affect the safety of the valve body against internal pressure and the flange connected with the bolt nut. Second, 60% of the valves under investigation had many voids in the valve body and flange, etc. and the decrease in thickness due to corrosion was relatively large on the inner surface in contact with water rather than the outer surface. It is judged that the investigation of depth included voids is very important factor. Third, all valves to be investigated are made of gray cast iron foam, and therefore it is judged that there is no major problem in chemical composition. It is judged that the chemical composition should be investigated. Fourth, as a physical investigation item, the analysis of metal morphology structure seems to be a very important factor for nodular cast iron from rather than a gray cast iron foam water valve with a flake structure. As it was found to be 46.7~68.8% of the standard recommended by KS, it could have a direct effect on damage such as cracks, and therefore it is judged that the evaluation of tensile strength is very important in evaluating the safety of the valve.

• Weed & Turfgrass Science
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• v.2 no.4
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• pp.362-367
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• 2013

This study was conducted to develop an efficient control method for water foxtail in the field sowing barley and wheat seeds before rice harvesting. When thifensulfuron-methyl (75%) was applied 0, 5 and 10 days after rice harvesting, little phytotoxicity was observed on both barley and wheat. Percent of water foxtail control with thifensulfuron-methyl (75%) was more than 88% at three different application timing. When butachlor (5%) was applied 5 days before barley and wheat sowing, phytotoxicity on barley and wheat was severe. However, no phytotoxicity was observed on barley and wheat 5 and 10 days after rice harvesting. Percent of water foxtail control with butachlor 0 and 5 days after rice harvesting was 85-89%. However, it dropped to 74-80% when applied 10 days after rice harvesting. In the thifensulfuron-methyl treatment, the dry matter of barley and wheat was 96-108% and 100-108%, respectively when compared with untreated control. While, in the butachlor treatment, the dry matter of barley and wheat was 53-73% and 106%, respectively when compared with untreated control. Therefore, we recommend thifensulfuron-methyl (75%) 0-10 days after rice harvesting or butachlor (5%) 5 days after rice harvesting to provide efficient water foxtail control and safe barley and wheat production.

• Food Science of Animal Resources
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• v.41 no.5
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• pp.802-815
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• 2021

To investigate the effect of postmortem phases on lamb meat quality, the physicochemical quality, microstructure and water mobility of oyster cut, short loin, knuckle and silverside muscles from Small-Tail Han sheep were evaluated in the pre-rigor, rigor mortis and post-rigor phases. Pre-rigor lamb meat had higher pH and water holding capacity (WHC), whereas lower CIE L^*, b^*, hue angle values than rigor mortis and post-rigor meat (p<0.05). The Warner-Bratzler shear force (WBSF) values were higher in rigor mortis short loin and silverside than their pre-rigor and post-rigor counterparts, pre-rigor short loin had lower WBSF value than its post-rigor counterpart (p<0.05). Muscle fibers shrank laterally and longitudinally during the onset of rigor mortis. Rigor mortis and postrigor lamb meat exhibited wide I-bands, dark A-bands, short sarcomeres and large inter-myofibrillar spaces. The shift of immobilized water to free water and repulsion from the intra-myofibrillar space to the extracellular space result in the increase of water loss in rigor mortis and post-rigor lamb meat. The results of the principal component analysis (PCA) indicated that rigor mortis and post-rigor lamb meat had similar quality properties but different from pre-rigor lamb meat. In conclusion, the lamb meat in the pre-rigor phase had good tenderness, color and WHC. The results of this research could provide some theoretical references for lamb meat production and processing.

• Korean journal of applied entomology
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• v.62 no.2
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• pp.95-102
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• 2023

The number of households with pets has increased in recent years. Consequently, interest in mites and their odors has increased. In this study, we investigated whether pyrethrum extract and water-soluble phytoncides are effective tick repellents, deodorizing agents, and antibacterial agents. In the tick-climbing test, the pyrethrum extract (23.33 points) and water-soluble phytoncide (22.00 points) showed a high repelling effect. To confirm the tick avoidance effect of the composite extract, a tick climbing test was conducted with a pest control extract, a composite extract (referred to as a sample) containing a water-soluble phytoncide, and a third-party product (control). The sample showed a high avoidance effect (13.00 points and Control 26.67 points. An indoor repellent efficacy test for ticks confirmed that the sample showed an excellent tick-repellent effect (88%) compared to the control (12%). As a result of a deodorization test, ammonia was shown to have a deodorizing effect of 98.3% and trimethylamine of 99.5%, whereas, in the antibacterial test, the E. coli, Staphylococcus aureus, and pneumonia groups showed an antibacterial effect of 99.9%. Combining the results of this study, it is judged that the complex extract including the above material has high utility value as a material that is effective in mite repellents, deodorization, and antibacterial activity.

• Journal of Ocean Engineering and Technology
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• v.10 no.4
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• pp.149-159
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• 1996

Multipurpose development of the coast and ocean can be considered as multifunction construction combining the functions of coastal protection, waterfront amenity and creation or rehabilitation of habitats. Multfunction development of coastal and ocean spaces can be accomplished by applying the ecosystem control structure of artificial habitats which will cultivate fishing ground with ecological harmony to the coastal protection system. To evaluate the applicability of ecosystem control structures as as fundamental coastal protection structure, wave control function of the structure is studied by numerical and physical analyses. Dimensional analysis and hydraulic experiment point out the importance of width and crest depth of ecosystem control structure, construction water depth and wave steepness. Wave control efficiency is estimated by the attenuation coefficient $(K_H)$ according to wave steepness $(H_0/L_0)$, relative constructed water depth $(h_i/H_0)$, relative berm width $(B/L_0)$ and relative crest depth $(h_B/H_0)$ of eosystem control structure. Empirical fomulas are suggested based on the results of model test by applying the multiple model based on this experimental results and numerical wave shoaling-dissipation-breaking model appears to be valid for the analysis of wave transformation around ecosystem control structure in the coastal waters.