• Journal of Korean Society of Disaster and Security
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• v.13 no.4
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• pp.75-92
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• 2020

In most cases of the water balance analysis, the return flow ratio for each water supply was uniformly determined and applied, so it has been contained a problem that the volume of available water would be incorrectly calculated. Therefore, sewage and wastewater among the return water were focused in this study and the data-driven model was developed to forecast the outflow from the sewage treatment plant. The forecasting results of LSTM (Long Short-Term Memory), GRU (Gated Recurrent Units), and SVR (Support Vector Regression) models, which are mainly used for forecasting the time series data in most fields, were compared with the observed data to determine the optimal model parameters for forecasting outflow. As a result of applying the model, the root mean square error (RMSE) of the GRU model was smaller than those of the LSTM and SVR models, and the Nash-Sutcliffe coefficient (NSE) was higher than those of others. Thus, it was judged that the GRU model could be the optimal model for forecasting the outflow in sewage treatment plants. However, the forecasting outflow tends to be underestimated and overestimated in extreme sections. Therefore, the additional data for extreme events and reducing the minimum time unit of input data were necessary to enhance the accuracy of forecasting. If the water use of the target site was reviewed and the additional parameters that could reflect seasonal effects were considered, more accurate outflow could be forecasted to be ready for climate variability in near future. And it is expected to use as fundamental resources for establishing a reasonable river water management system based on the forecasting results.

• Journal of the Korean Geotechnical Society
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• v.23 no.10
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• pp.97-107
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• 2007

Accurate evaluation of the slope stability by assuming failure block as the entire slope is considered to be apposite for the small scale slope, whereas it is not the case for the large scale slope. Hence, appropriate estimation of a failure block size is required since the safety factor and the joint strength parameters are the function of the failure block size. In this paper, the size of failure block was investigated by generating 3-dimensional rock joint system based on statistical data of joints obtained from research slope, such as joint orientation, spacing and 3-dimensional joint intensity. The result indicates that 33 potential failure blocks exist in research slope, as large as 1.4 meters at least and 38.7 meters at most, and average block height is 15.2 meters. In addition, the data obtained from 3 dimensional joint system were directly applicable to the probability analysis and 2 and 3 dimensional discontinuity analysis.

• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.19-31
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• 2023

According to the climate change scenarios, the intensity of typhoons, a major factor in Korea's natural disaster, is expected to increase. The increase in typhoon intensity leads to a rise in wave heights, which is likely to cause large-scale disasters in coastal regions with high populations and building density for dwelling, industry, and tourism. This study, therefore, analyzed observation data of the Donghae ocean data buoy and conducted a numerical model simulation for wave estimations for the typhoon MAYSAK (202009) period, which showed the maximum significant wave height. The boundary conditions for wave simulations were a JMA-MSM wind field and a wind field applying the typhoon central pressure reduction rate in the SSP5-8.5 climate change scenario. As a result of the wave simulations, the wave height in front of the breakwater at Sokcho port was increased by 15.27% from 4.06 m to 4.68 m in the SSP5-8.5 scenario. Furthermore, the return period at the location of 147-2 grid point of deep-sea design wave was calculated to increase at least twice, it is necessary to improve the deep-sea design wave of return period of 50-year, which is prescriptively applied when designing coastal structures.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.1
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• pp.51-62
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• 2009

This study was carried out development a new composting system to lower copper and zinc concentration in plg sludge compost and conduct an inquiry into the possibility of crop cultivation. The concentrations of nitrogen, phosphorus and pH averaged 4.4%, 6.3% and 7.57, respectively, which were higher concentrations than in commercial organic fertilizers, and the concentrations of copper and zinc averaged 805 and 1,704 mg/kg, respectively, which were beyond the heavy metal concentration limit in byproduct compost. Hydrated citric acid I lowered the concentrations of copper and zinc by 58% and 97%, respectively and hydrated oxalic acid II lowered the concentrations of copper and zinc by 48% and 56%, respectively in pig sludge compost. Lower concentrations of copper and zinc in pig sludge resulted from the enhanced hydrated-citric acid concentration in organic acid solution mixed with distilled water. The concentrations of copper and zinc were 330, and 41 mg/kg in the pig sludge treated with 100% hydrated citric acid. Agitation composting system stabilized the compost earlier than the stationary composting system, in which the stabilization condition was confirmed by higher temperature by $4^{\circ}C$ at highest temperature and 7 days earlier cooling down after highest temperature. The levels of germination index (G.I) 80 were obtained 15 and 20 days after composting in agitation and stationary composting system, respectively. The concentrations of copper and zinc were 2.4 and 4.26 mg/kg respectively in soils amended with pig sludge compost after removing process of heavy metals by citric acid, but 8.0 and 22.37 mg/kg, respectively in soils amended with Pig Sludge. The concentrations of heavy metals was highest in com cultivated in soils amended with pig sludge. The copper and zinc concentrations In corn leaves were 75.2 and 50.56 mg/kg respectively, which were 4 and 2 fold higher than the com cultivated in soils amended with pig sludge compost after heavy metal removing process by hydrated citric acid.

• Journal of Food Hygiene and Safety
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• v.39 no.1
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• pp.35-43
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• 2024

Numerous methods have been applied to assess the antibacterial effectiveness of hand hygiene products. However, the different results obtained through various evaluation methods have complicated our understanding of the real efficacy of the products. Few studies have compared test methods for assessing the efficacy of hand hygiene products. In particular, reports on ex vivo pig skin testing are limited. This study aimed to compare and characterize the methodologies applied for evaluating hand hygiene products, involving in vitro, ex vivo, and in vivo approaches, applicable to both leave-on sanitizers and wash-off products. Our further aim was to enhance the reliability of ex vivo test protocols by identifying influential factors. We performed an in vitro method (EN1276) and an in vivo test (EN1499 and ASTM2755) with at least 20 participants, against Serratia marcescens or Escherichia coli and Staphylococcus aureus. For the ex vivo experiment, we used pig skin squares prepared in the same way as those used in the in vivo test method and determined the optimal treated sample volumes for sanitizers and the amount of water required to wash off the product. The hand sanitizers showed at least a 5-log reduction in bacterial load in the in vitro test, while they showed little antibacterial activity in the in vivo and ex vivo tests, particularly those with a low alcohol content. For the hand wash products, the in vitro test was limited because of bubble formation or the high viscosity of the products and it showed low antibacterial activity of less than a 1-log reduction against E. coli. In contrast, significantly higher log reductions were observed in ex vivo and in vivo tests, consistently demonstrating these results across the two methods. Our findings revealed that the ex vivo and in vivo tests reflect the two different antibacterial mechanisms of leave-on and wash-off products. Our proposed optimized ex vivo test was more rapid and more precise than the in vitro test to evaluate antibacterial results.

• Clean Technology
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• v.22 no.2
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• pp.122-131
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• 2016

Caesium radioisotopes, ¹³⁴Cs and ¹³⁷Cs which come from the atmospheric nuclear tests and discharges from nuclear power plants, are very important to study artificial radioactivity. In this work, in order to lower the minimum detection activity (MDA) we investigated environmental radioactivity according to the Environment Measurement Laboratory procedure by ¹³⁷Cs and ¹³⁴Cs which is similar to chemical and environmental behaviors of ¹³⁷Cs. The environmental soils in high mountain areas near nuclear power plant were collected, and an Ammonium Molybdophosphate (AMP) precipitation method, which showed high selectivity toward Cs⁺ ions, was applied to chemically extract and concentrate Caesium radioisotopes. Radioactivity was estimated by a gamma-ray spectrometry. In gamma energy spectrum, with an increasing of ⁴⁰K radioactivity, it increased the MDA of ¹³⁴Cs and ¹³⁷Cs. Therefore, if the natural radionuclides were removed from the soil samples, the MDA of Caesium may be reduced, and the contents of ¹³⁷Cs of in the environmental soils can effectively be estimated. In the standard soil sample of Korea Institute of Nuclear Safety, radioactivity of ⁴⁰K was removed more than 84% on average, and the MDA of ¹³⁴Cs was reduced 2 times. The content of ¹³⁷Cs was recovered over 84%. On the other hand, in environmental soils, AMP precipitation method showed removal ratio of ⁴⁰K up to 180 times, which reduced the MDA about 5 times smaller than those of Direct method. ¹³⁷Cs recovery ratio showed from 54.54% to 70.06%. When considering the MDA and recovery ratio, AMP precipitation method is effective for detection of Caesium radioisotopes in low concentration.

• Journal of Food Hygiene and Safety
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• v.36 no.5
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• pp.430-439
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• 2021

Essential oils with excellent antibacterial activity were used to study the inhibitory effect against the six types of food poisoning biofilms formed on the surfaces of polyethylene (PE) and stainless steel (SS) that are widely used for food processing instruments and containers. The antibacterial activity of 20 kinds of essential oils was tested using the disk diffusion method. The result showed the degree of antibacterial activity in the following order: cinnamon> clove> lemongrass> peppermint> pine needle (highest to lowest). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of cinnamon and clove oil were in the range of 0.63-1.25 mg/mL and 1.25-2.50 mg/mL, respectively. The MIC and MBC of lemongrass oil were 1.25-2.50 mg/mL and 2.50-5.00 mg/mL, respectively, showing slightly less antibacterial activity. Although the preventive effect of three types of essential oils on the biofilm formation differed slightly depending on food poisoning bacteria, PE, and SS, it was found that the precoating of 0.5% cinnamon, clove, and lemongrass oil on the PE and SS affects the formation of biofilm. Increased essential oil concentration significantly inhibited the biofilm formation for all food poisoning bacteria (P<0.05), and biofilms of Listeria monocytogenes and Staphylococcus aureus were not formed when treated with 0.5% cinnamon and clove oil. The elimination effect of food poisoning bacteria biofilms formed on the surfaces of PE and SS differed depending on the type of food poisoning bacteria. Still, the biofilm elimination effect increased as the essential oil concentration increased, and the biofilm elimination rate of clove oil was generally high. Therefore, this study found that the cinnamon and clove essential oils (0.5%) are suitable natural materials that effectively prevent, inhibit, and remove the biofilms formed by the food poisoning bacteria on the surfaces of polyethylene and stainless steel.

• Food Science and Preservation
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• v.16 no.5
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• pp.650-655
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• 2009

This study was conducted to measure the quality characteristics of rough rice during low temperature drying by using an experimental dryer and heat pump with a capacity of 150kg at four temperature levels of 20, 30, 40, and $50^{\circ}C$. The quality and proper drying temperature of rough rice was investigated by measuring variations in moisture content, crack rates, germination rates and cooked rice. Temperatures over $40^{\circ}C$ is considered a high-temperature area, and below $40^{\circ}C$ is considered a low-temperature area. The drying rates were 0.3, 0.6, 0.9, and 1.3%/hr, and the crack ratios were 0, 1.6, 6.8, and 24.2% at the drying temperatures of 20, 30, 40, and $50^{\circ}C$, respectively, which showed that the higher the drying temperature was, the higher the drying rate and crack rate was. Therefore, 20 and $30^{\circ}C$ were found to be appropriate drying temperatures for avoiding crack formation, and $50^{\circ}C$ was inappropriate. At $40^{\circ}C$, the operation methods needed to be modified to limit cracking, such as increasing the tempering time. Also, as the drying temperature increased, the germination rate decreased. Germination rates at 20 and $30^{\circ}C$ were suitable for using the rough rice as a seed, and those at 40 and $50^{\circ}C$ were over 80%, which is the minimum allowable percentage. In the sensory evaluation of cooked rice, the quality of appearance, taste, and texture varied as a function of drying temperature. When considering these factors, the cooked rice that was dried at 20 and $30^{\circ}C$ was better than the cooked rice dried at high-temperature. Consequently, in view of drying temperature and rates, the best conditions for drying rough rice were below $30^{\circ}C$ and below 0.6%/hr.

• Journal of Korean Academy of Nursing
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• v.25 no.3
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• pp.597-607
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• 1995

1960년대 이후 인공호흡기(mechanical ventilator)의 보급과 최근 의료과학의 발달, 간호의 질적 향상의 결과로 저체중출생아를 포함한 고위험 신생아의 생존율이 높아져왔다. 호흡장애증후군(RDS)은 일차적으로 폐포의 완전한 확장을 위해 필요한 계면활성물질(surfactant)의 부족, 미발달된 심폐기능에 의한 병리적 현상으로 저체중아의 가장 큰 원인이 되어왔다. RDS로 인해 인공호흡기에 의존해 있는 저체중아의 경우 적절한 산소공급과 이를 위한 호흡의 유지는 치료의 가장 큰 핵심이 되며, 이를 위한 기관내 흑은 비인두 흡인 (nasopharyngeal suction)은 신생아 중환자실(NICU)의 가장 중요한 간호행위가 되어왔다. 인공호흡기를 위한 기관삽관은 그 자체가 기도의 성모운동을 방해하고 기침반사를 억제시켜 폐 분비물의 효과적 배출을 억제하며, 특히 저체중아의 경우 조산과 관련하여 미발달된 흥곽운등과 심폐기능은 폐분비물의 이동을 저해하는 요소이다. 따라서 기도내의 분비물의 이동을 효과적으로 하여 흡인 시에 최대한의 효과를 돕기 위해 흥곽 물리요법(chest physiotheraphy : CPT)의 한 형태인 흉곽진동법 (Chest Vibration : CV)가 행해져 왔다. 그러나 저체중아를 위한CV의 임상적 적용은 그 대상의 생리적 특성, CV의 적용부위(site)와 기간(duration)에 대한 과학적 근거 없이 만성감염이나 폐질환을 가진 성인이나 cystic fibrosis환자를 위한 CV protocol을 무분별하게 채택하여 저체중아에게 행하여져 왔다 이에 본 연구자는 저체중아에 대한 CV의 안전성을 평가하고, 이에 기초하여 저체중아에게 바람직한CV의 형태를 알아보고자 본 연구를 시작하였다. 연구설계는 CV의 안전성을 평가하기 위한 실험연구이다. CV의 안전성은 RDS치료의 가장 일차적 목표인 oxygenation변화에 의해 평가될 수 있으므로, 본 실험 연구에서는 Pulse oximeter에 의해 계속적으로 측정된 산소포화 변화(oxygen saturation change)를 측정하였다. 실험대상은 미국동부에 위치한 대학병원의 NICU에 입원하여 RDS와 관련된 호흡장애로 인공호흡기에 의존해 있는 10명의 저체중아였다. 인공호흡기에 의존된 모든 저체중아는 Pulse oximeter와 심폐기능 측정기(cardiopulmonary monitor)에 의해 산소공급과 호흡상태가 계속 측정되고 있었다. 실험대상의 평균 출생시 몸무게는 평균 1,3050gm(SD=580.6)이었고, 임신월령 은 평균 28.6주(SD=3.1)였다. RDS가 그들의 일차적 진단명이었고, 그중 4명은 pneumonia, atelectasis의 합병증을 가지고 있었다. 10명중 6명은 intermittent mandatory ventilation(IMV)의 형태로, 4명은 continuous positive airway pressure(CPAP)의 형태로 인공호흡기에 의존되어 있었고 CV시의 FiO2는 평균 42.3(SD=21.2)였다. CV는 중환아용 소형진동기 (minivibrator)를 이용해 가각 10명 의 간호사에 의해 행하여 졌고, 최소 22초에서 최대 100초 동안 실시되었다. 50%의 간호사는 30초에서 40초간 CV를 실시하였으며, CV의 적용부위도, 전후 흉곽부위, 혹은 병변이 있는 좌 우측, 흑은 양쪽 흉벽 등으로 다양했고, 적용방법도 원형으로 돌려가며(circular motion), 혹은 아래에서 위로, 혹은 아무런 기준없이 간호사의 기호에 따라 다양하게 적용되었다. 산소포화의 변화는 CV가 행해지기 전.후로 5초동안 관찰되었다. 연구의 결과, 산소포화 변화는 비 모수통계(non parametric statistics)의 일종인 Matched Paired Wilcoxon test로 분석 한 결과 CV후에 3%의 감소를 보였다(P<.05). 저체중아에 있어 산소포화의 3%감소는 임상적으로 중요한 의미가 없다고 사료되어지며, 실제 흡인전의 과도호흡에 의해 CV를 행하기 이전의 산소공급수준으로 돌아 왔다. CV실시 기간과 산소포화와의 상관관계는 비 모수통계인 Spearman rho correlation coefficient를 이용하여 분석하였는데, 이 두 변수는 서로 관계가 없는 것으로 나타났다(P>.05) 또한 CV와 흡인 후에 각각의 간호사들에게 CV를 필요로 한 저체중아의 기준, 적용부위, 기간, 방법등에 대한 기준을 물었으나 대상의 특성에 따른 간호사정에 의존하기보다는 간호사 각자의 선호하는 방법이나 습관에 라 행하는 것으로 나타났다. 결론적으로 CV와 산소포화 변화와의 관계, NICU에서 관찰된 CV의 임상적 적용을 기초로 저체중아에게 안전한 CV protocol은 신생아용 소형 진동기를 이용하여, 양쪽 흉곽의 늑골하측 변연 부위(low lateral costal margin)에서 시작하여 흉골 중앙부위 방향으로 30초 동안 진동기를 적용하는 것이 좋은 것으로 나타났다. 이에 CV의 효과를 평가하기 위한 보다 과학적인 접근방법으로, CV와 흡인의 결과인 가래(sputum)에 대한 연구를 제언하는 바이다.

• Journal of Chest Surgery
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• v.40 no.1 s.270
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• pp.37-44
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• 2007

Background: It is known that long-term survival rate in patients underwent bronchial sleeve lobectomy for primary lung cancer is at least equal to that in patients underwent pneumonectomy, and bronchial sleeve lobectomy is performed in patients with suitable tumor location even in patients have adequate pulmonary function. Sleeve pneumonectomy is performed when carina was invaded by tumor or tumor location was near to the carina. We performed this study to know our results of sleeve resection for primary lung cancer. Material and Method: We analyzed retrospectively the medical records of 45 patients who underwent sleeve lobectomy or sleeve pneumonectomy for primary lung cancer by one thoracic surgeon from May 1990 to July 2003 in Department of Thoracic & Cardiovascular Surgery, College of Medicine, Kyung Hee University. Follow-up loss was absent and last follow-up was performed in April 5, 2005. Kaplan-Meyer method and log-lank test were used to know long-term survival rate and p-value. Result: Mean age was 60 years old and male to female ratio 41:1. Histologic types were squamous cell carcinoma were 39, adenocarcinoma were 4, and others were 2 patients. Pathologic stages were I 14, II 14, and III 17 patients. Nodal stages were N0 23, N1 13, and N2 9 patients. Types of operation were sleeve lobectomy 40 and sleeve pneumonectomy 5 patients. Operative mortality was 3 patients and its cause was respiratory complications. Early complications were pneumonia 4, atelectasis 8, air leakage more than 7 days 6, and atrial fibrillation 4 patients. In 19 patients tumor was recurred. Local recurrence was 10 and systemic metastasis was 9 patients. Overall 5, 10-year survival rate were 54.2%, 42.5%. The 5, 10-year survival rates according to the pathologic stage were 83.9%, 67.1% in stage I, 55%, 47.1% in II, 33.3%, 25% in III, and significance difference was present between stage I and III. The 5, 10-year survival rate according to the lymph node involvement were 63.9%, 54.6% in N0, 53,8%, 46.5% in N1, 28.5%, 14.2% in N2, and significance difference was present between N0 and N2. Conclusion: Because bronchial sleeve lobectomy for primary lung cancer could be performed safely and shows acceptable long-term survival rate, it could be considered primary in case of suitable tumor location if complete resection is possible. Although sleeve pneumonectomy for primary lung cancer shows somewhat high operative mortality rate, it could be considered in view of curative treatment.