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        검색결과 159

        21.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The water consumption data of individual consumers must be analyzed and forecast to establish an effective water demand management plan. A k-mean cluster model that can monitor water use characteristics based on hourly water consumption data measured using automated meter reading devices and demographic factors is developed in this study. In addition, the quantification model that can estimate the daily water consumption is developed. K-mean cluster analysis based on the four clusters shows that the average silhouette coefficient is 0.63, also the silhouette coefficients of each cluster exceed 0.60, thereby verifying the high reliability of the cluster analysis. Furthermore, the clusters are clearly classified based on water usage and water usage patterns. The correlation coefficients of four quantification models for estimating water consumption exceed 0.74, confirming that the models can accurately simulate the investigated demographic data. The statistical significance of the models is considered reasonable, hence, they are applicable to the actual field. Because the use of automated smart water meters has become increasingly popular in recent year, water consumption has been metered remotely in many areas. The proposed methodology and the results obtained in this study are expected to facilitate improvements in the usability of smart water meters in the future.
        5,100원
        25.
        2022.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In severe acute pancreatitis, accompanied by local complications such as acute peripancreatic fluid collection, pancreatic pseudocyst, acute necrotic collection and walled-off necrosis, the mortality rate is as high as 12-25%. In many cases, interventional procedure or surgical treatment are required at an appropriate time. Conservative treatment is considered for acute peripancreatic fluid collection. Endoscopic drainage could be considered preferentially for the treatment of pancreatic pseudocysts with clinical symptoms or complications. In the case of necrotizing pancreatitis, conservative treatment is preferred, but therapeutic intervention should be considered if infectious pancreatic necrosis with clinical deterioration is suspected. For therapeutic intervention, it is recommended to proceed with a step-up approach in which drainage is first performed and, if necessary, necrosectomy is performed. The optimal timing of intervention is considered 4 weeks after the onset of pancreatitis when necrosis become walled-off, but early drainage within 4 weeks can be considered depending on the patient's condition. This guideline provides an overview of current treatment strategies for local complications of acute pancreatitis.
        4,000원
        26.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The water supply facilities of Korea have achieved a rapid growth, along with the other social infrastructures consisting a city, due to the phenomenon of urbanization according to economic development. Meanwhile, the level of water supply service demanded by consumer is also steadily getting higher in keeping with economic growth. However, as an adverse effect of rapid growth, the quantity of aged water supply pipes are increasing rapidly, Bursts caused by pipe aging brought about an enormous economic loss of about 6,161 billion won as of 2019. These problems are not only worsening water supply management, also increasing the regional gap in water supply services. The purpose of this study is to classify hazard evaluation indicators and to rank the water distribution network hazard by cluster using the TOPSIS method. In conclusion, in this study, the entropy-based multi-criteria decision-making methods was applied to rank the hazard management of the water distribution network, and the hazard management ranking for each cluster according to the water supply conditions of the county-level municipalities was determined according to the evaluation indicators of water outage, water leakage, and pipe aging. As such, the hazard ranking method proposed in this study can consider various factors that can impede the tap water supply service in the water distribution network from a macroscopic point of view, and it can be reflected in evaluating the degree of hazard management of the water distribution network from a preventive point of view. Also, it can be utilized in the implementation of the maintenance plan and water distribution network management project considering the equity of water supply service and the stability of service supply.
        4,800원
        30.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        (PIM-1)과 ellagic acid로 만든 랜덤형 공중합체가 간단한 방법으로 합성되었으며, 이산화탄소 분리막에 대한 적용 가능성에 대해서 연구하였다. 이 공중합체의 경우 PIM (polymers with intrinsic microporosity) 고분자의 미세 기공 구조에 기 인한 높은 기체 투과도와 평면 구조와 친수성을 갖는 ellagic acid에 기인한 높은 이산화탄소에 대한 선택성에 의해 우수한 이 산화탄소 기체 분리 성능을 나타내었다. 즉, 이산화탄소에 대한 투과도 4516 Barrer와 CO2/N2 (> 23~26) 및 CO2/CH4 (> 18~19)의 높은 선택성으로 두 쌍의 가스 혼합물에 대해 Robeson 상한(2008)을 초과한 결과를 나타내었다. 이와 같이 PIM-1 에 평면구조를 갖는 ellagic acid을 혼입하면 PIM-1의 꼬인 구조를 방해하여 기체 투과성을 향상 시킬 뿐만 아니라 공중합체 의 강성과 극성이 증가하여 N2 및 CH4에 대한 CO2의 선택성을 증가시키는 결과를 확인하였다.
        4,500원
        31.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 미생물을 이용하여 개발한 발효 스쿠알렌의 안정성 향상을 위하여 마이크로좀 -SQ20 (Microsome-SQ20)을 제조하고, 이에 대한 물리적 거동 및 특성과 효능효과에 대하여 연구하였다. 마이크로좀-SQ20의 외관은 투명한 액체로 고유의 냄새를 가지고 있었다. 색상은 무색이고, 비중은 0.928, pH는 5.82 (20%용액)로 화장품에 사용하는데 적합한 나노에멀젼이 형성되었다. 스쿠알렌의 주성분 함량은 20.05%로 안정하게 봉입이 된 것을 확인할 수 있었다. 마이크로좀-SQ20을 0.1% 수용액화하여 측정한 입자크기는 134.8 nm로 bluish한 유화상을 얻었다. F-SQ(Fermented squalene)과 MF-SQ(Microsome squalene)의 DPPH라디칼에 의한 항산화 효과는 각각 80.72%, 81.5%로, L-ascorbic acid와 비교하여 동 등한 효과를 보였다. F-SQ 및 MF-SQ은 10 ppm에서 각각 150.3%, 129.9%의 세포생존율을 나타냈다. SQ, F-SQ, MF-SQ의 elastase 저해능은 10 ppm에서 각각 8.7%, 10.33%, 8.7%의 저해능력을 가지고 있음을 알 수 있었다. MMP-1 저해능력은 SQ, F-SQ, MF-SQ 모두 10 ppm에서 각각 1.55%, 41.44%, 31.79%를 나타내 F-SQ의 collagenase 저해능이 우수한 것을 알 수 있었다.
        4,300원
        33.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, a model to optimize residual chlorine concentrations in a water supply system was developed using a multi-objective genetic algorithm. Moreover, to quantify the effects of optimized residual chlorine concentration management and to consider customer service requirements, this study developed indices to quantify the spatial and temporal distributions of residual chlorine concentration. Based on the results, the most economical operational method to manage booster chlorination was derived, which would supply water that satisfies the service level required by consumers, as well as the cost-effectiveness and operation requirements relevant to the service providers. A simulation model was then created based on an actual water supply system (i.e., the Multi-regional Water Supply W in Korea). Simulated optimizations were successful, evidencing that it is possible to meet the residual chlorine concentration demanded by consumers at a low cost.
        4,200원
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