• Journal of Chest Surgery
• /
• v.56 no.3
• /
• pp.162-170
• /
• 2023

Background: Extracorporeal cardiopulmonary resuscitation (E-CPR) plays an indispensable role when resuscitation fails; however, extracorporeal life support (ECLS) in infants is different from that in adults. The objective of this study was to evaluate the outcomes of E-CPR in infants. Methods: A single-center retrospective study was conducted, analyzing 51 consecutive patients (age <1 year) who received E-CPR for in-hospital cardiac arrest between 2010 and 2021. Results: The median age and body weight was 51 days (interquartile range [IQR], 17-111 days) and 3.4 kg (IQR, 2.9-5.1 kg), respectively. The cause of arrest was cardiogenic in 45 patients (88.2%), and 48 patients (94.1%) had congenital cardiac anomalies. The median conventional cardiopulmonary resuscitation (C-CPR) time before the initiation of ECLS was 77 minutes (IQR, 61-103 minutes) and duration of ECLS was 7 days (IQR, 3-12 days). There were 36 in-hospital deaths (70.6%), and another patient survived after heart transplantation. In the multivariate analysis, single-ventricular physiology (odds ratio [OR], 5.05; p=0.048), open sternum status (OR, 8.69; p=0.013), and C-CPR time (OR, 1.47 per 10 minutes; p=0.021) were significant predictors of in-hospital mortality. In a receiver operating characteristic curve, the optimal cut-off of C-CPR time was 70.5 minutes. The subgroup with early E-CPR (C-CPR time <70.5 minutes) showed a tendency for lower in-hospital mortality tendency (54.5% vs. 82.8%, p=0.060), albeit not statistically significant. Conclusion: If resuscitation fails in an infant, E-CPR could be a life-saving option. It is crucial to improve C-CPR quality and shorten the time before ECLS initiation.

• Journal of the Korea Society for Simulation
• /
• v.18 no.3
• /
• pp.103-112
• /
• 2009

In a nuclear power plant (NPP), periodic sensor calibrations are required to assure sensors are operating correctly. However, only a few faulty sensors are found to be calibrated. For the safe operation of an NPP and the reduction of unnecessary calibration, on-line calibration monitoring is needed. In this paper, principal component-based Auto-Associative support vector regression (PCSVR) was proposed for the sensor signal validation of the NPP. It utilizes the attractive merits of principal component analysis (PCA) for extracting predominant feature vectors and AASVR because it easily represents complicated processes that are difficult to model with analytical and mechanistic models. With the use of real plant startup data from the Kori Nuclear Power Plant Unit 3, SVR hyperparameters were optimized by the response surface methodology (RSM). Moreover the statistical techniques are integrated with PCSVR for the failure detection. The residuals between the estimated signals and the measured signals are tested by the Shewhart Control Chart, Exponentially Weighted Moving Average (EWMA), Cumulative Sum (CUSUM) and generalized likelihood ratio test (GLRT) to detect whether the sensors are failed or not. This study shows the GLRT can be a candidate for the detection of sensor drift.

• Nuclear Engineering and Technology
• /
• v.27 no.6
• /
• pp.877-887
• /
• 1995

YGN 3 is the first nuclear power plant to use the Core Protection Calculator (CPC) as the core protection system and the Core Operating Limit Supervisory System (COLSS) as the core monitor-ing system in Korea. The CPC is designed to provide on-line calculations of Departure from Nucleate Boiling Ratio (DNBR) and Local Power Density (LPD) and to initiate reactor trip if the core conditions exceed the DNBR or LPD design limit. The COLSS is designed to assist the operator in implementing the Limiting Conditions for Operation (LCOs) in Technical Specifications for DNBR/Linear Heat Rate (LHR) margin, azimuthal tilt, and axial shape index and to provide alarm when the LCOs are reached. During YGN 3 initial startup testing, extensive CPC/COLSS related tests ore peformed to ver-ify the CPC/COLSS performance and to obtain optimum CPC/COLSS calibration constants at var, -ious core conditions. Most of test results met their specific acceptance criteria. In the case of missing the acceptance criteria, the test results ore analyzed, evaluated, and justified. Through the analysis and evaluation of each of the CPC/COLSS related test results, it can be concluded that the CPC/COLSS are successfully Implemented as designed at YGN 3.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.2
• /
• pp.157-168
• /
• 2009

In this paper, a photovoltaic system is designed with a step up chopper and single phase PWM(Pulse Width Modulation) voltage source inverter. Where proposed Synchronous signal and control signal was processed by one-chip microprocessor for stable modulation. The step up chopper operates in continuous mode by adjusting the duty ratio so that the photovoltaic system tracks the maximum power point of solar cell without any influence on the variation of insolation and temperature because solar cell has typical voltage and current dropping character. The single phase PWM voltage source the inverter using inverter consists of complex type of electric power converter to compensate for the defect, that is, solar cell cannot be developed continuously by connecting with the source of electric power for ordinary use. It can cause the effect of saving electric power. from 10 to 20[%]. The single phase PWM voltage source inverter operates in situation that its output voltage is in same phase with the utility voltage. In order to enhance the efficiency of photovoltaic cells, photovoltaic positioning system using sensor and microprocessor was design so that the fixed type of photovoltaic cells and photovoltaic positioning system were compared. In result, photovoltaic positioning system can improved 5% than fixed type of photovoltaic cells. In addition, I connected extra power to the system through operating the system voltage and inverter power in a synchronized way by extracting the system voltage so that the phase of the system and the phase of single-phase inverter of PWM voltage type can be synchronized. And, It controlled in order to provide stable pier to the load and the system through maintaining high lurer factor and low output power of harmonics.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.33 no.2
• /
• pp.171-187
• /
• 2023

Objectives: Aircraft cabin cleaning work is characterized by being performed within a limited time in a narrow and enclosed space. The objective of this study was to evaluate the exposure levels to dust, ultra fine dust(PM2.5) and black carbon(BC) among aircraft cabin cleaners. Methods: Active personal air sampling for respirable dust(n=73) and BC(n=47) was conducted during quick transit cleaning(cabin general and vacuum-specific) and seat cover replacement and total dust and PM2.5 were area-air-sampled as well. Also, size distribution of particle was identified with the cleaning workers targeted. Dusts were collected with PVC filters using gravimetric analysis. The concentration of PM2.5 and the particle size distribution were measured with real-time direct reading portable equipment using light scattering analysis. The concentration of BC was measured by aethalometer(filter-based real-time light absorption analysis instrument). Results: The geometric mean of respirable dust was the highest at vacuum cleaning as 74.4 ㎍/m³, following by replacing seat covers as 49.3 ㎍/m³ and cabin general cleaning as 47.8 ㎍/m³ . The arithmetic mean of PM2.5 was 4.83 ~ 9.89 ㎍/m³ inside the cabin, and 28.5~44.5 ㎍/m³ outside the cabin(from bus and outdoor waiting space). From size distribution, PM_2.5/PM₁₀ ratio was 0.54 at quick transit cleaning and 0.41 at replacing seat covers. The average concentration of BC was 2~7 ㎍/m³, showing a high correlation with the PM2.5 concentration. Conclusions: The hazards concentration levels of aircraft cabin cleaners were very similar to those of roadside outdoor workers. As the main source of pollution is estimated to be diesel vehicles operating at airports, and it is necessary to replace older vehicles, strengthen pollutant emission control regulations, and introduce electric vehicles. In addition, it is necessary to provide as part of airport-inftastructure a stable standby waiting space for aircraft cabin cleaners and introduce a systematic safety and health management system for all workers in the aviation industry.

• Journal of Chest Surgery
• /
• v.56 no.4
• /
• pp.244-251
• /
• 2023

Background: Extracorporeal membrane oxygenation (ECMO) has been widely used in patients with cardiorespiratory failure. The serum albumin level is an important prognostic marker in critically ill patients. We evaluated the efficacy of using pre-ECMO serum albumin levels to predict 30-day mortality in patients with cardiogenic shock (CS) who underwent venoarterial (VA) ECMO. Methods: We reviewed the medical records of 114 adult patients who underwent VA-ECMO between March 2021 and September 2022. The patients were divided into survivors and non-survivors. Clinical data before and during ECMO were compared. Results: Patients' mean age was 67.8±13.6 years, and 36 (31.6%) were female. The proportion of survival to discharge was 48.6% (n=56). Cox regression analysis showed that the pre-ECMO albumin level independently predicted 30-day mortality (hazard ratio, 0.25; 95% confidence interval [CI], 0.11-0.59; p=0.002). The area under the receiver operating characteristic curve of albumin levels (pre-ECMO) was 0.73 (standard error [SE], 0.05; 95% CI, 0.63-0.81; p<0.001; cut-off value=3.4 g/dL). Kaplan-Meier survival analysis showed that the cumulative 30-day mortality was significantly higher in patients with a pre-ECMO albumin level ≤3.4 g/dL than in those with a level >3.4 g/dL (68.9% vs. 23.8%, p<0.001). As the adjusted amount of albumin infused increased, the possibility of 30-day mortality also increased (coefficient=0.140; SE, 0.037; p<0.001). Conclusion: Hypoalbuminemia during ECMO was associated with higher mortality, even with higher amounts of albumin replacement, in patients with CS who underwent VA-ECMO. Further studies are needed to predict the timing of albumin replacement during ECMO.

• Environmental and Resource Economics Review
• /
• v.32 no.2
• /
• pp.107-126
• /
• 2023

This study analyzes the financial efficiency of the early scappage support system using the benefit and cost analysis. To do so, we use comprehensive administrative data on the early scrappage of old diesel vehicles. The result shows that the benefit-cost ratio was greater than 1 before 2020, but it appeared to be less than 1 after 2020. This indicates that despite recent reforms to increase the subsidy of early scrappage of old diesel vehicles, the rate of the benefit of air quality improvement is not as fast as the increase in system operation cost of this system. The benefit of air quality improvement depends on how much the operating period is shortened due to early scrappage support system. The earlier this period is brought forward, the more likely it is that the benefits of early scrappage will exceed the costs. Upon examining the results of this study, it was found that when the scrappage timing is brought forward by 5 years, the B/C for 98% of the samples becomes 1, greatly securing financial efficiency. Therefore, it is important for the government to reform the system so that it can influence the decision of old diesel vehicle owners on the timing of scrappage.

• The Korean Journal of Franchise Management
• /
• v.5 no.1
• /
• pp.85-108
• /
• 2014

This study provides the information about size, financial structure, profitability and growth of franchisors using financial data(asset, liability, equity, sales volume, operating income and net income) in uniform franchise offering circular of fair trade commission. The data were collected from 1,050 franchisors in various business fields: fast food, family restaurant, bakery, agriculture & fishery and liquor shop in the uniform franchise offering circular in 2012 and 2011. Results of this study are as follows: For company size, median of total assets was KRW 675 million and the accumulated median assets rate was 0.48%, but the accumulated median company numbers were 49.9%, which showed small size. For financial structure, 525 companies were below 200% debt ratio, while 314 (29.9%) companies were in over 200% debt, and 211 (20.1%) companies were impaired in capital. These also showed financial structure was vulunerable. For profitability, median of ROA for total companies were only 4.72%, which showed low profitability. For growth, median of growth rate for sales were 7.57% per year, which showed mature industry. In overall, the results showed franchisors should improve their financial status.

• Health Policy and Management
• /
• v.33 no.3
• /
• pp.355-362
• /
• 2023

Background: Financial efficiency in monetary units and operational efficiency in non-monetary units are separately classified and evaluated. This is done to prevent the duplication of monetary units and non-monetary units in inputs and outputs. In addition, analyses are conducted to determine the factors that affect each aspect of efficiency. To prevent duplication of monetary and non-monetary units in inputs and outputs, financial efficiency, consisting of monetary units, and operational efficiency, comprising non-monetary units, are separately classified and evaluated. Furthermore, an analysis is conducted to identify the factors that affect each aspect of efficiency. Methods: This study conducted a panel analysis of 34 regional public hospitals and influencing factors on efficiency for 5 years from 2015 to 2019. Financial efficiency and operational efficiency were calculated through data envelopment analysis. Moreover, multiple regression analysis was conducted to identify the factors that influence both financial efficiency and operational efficiency. Results: The factors that affect financial efficiency include the number of medical institutions within the treatment area and the ratio of patients receiving medical care. Additionally, operational efficiency is influenced by the type of medical institution, the number of medical institutions within the treatment area, and the number of nursing positions per 100 beds. Conclusion: In order for regional public hospitals to faithfully fulfill their functions and roles as regional base public hospitals, several measures are necessary. Firstly, continuous monitoring and reasonable support are required to ensure efficient operation and performance. Secondly, a financial support plan tailored to the characteristics of local medical centers is needed. Additionally, local medical centers should strive to enhance their own efficiency.

• Journal of radiological science and technology
• /
• v.46 no.5
• /
• pp.367-377
• /
• 2023

This study investigates the utility of the Triglyceride-glucose(TyG) index and Cardiometabolic Index(CMI) as predictors for diagnosing metabolic syndrome. The study involved 1970 males, 1459 females, totaling 3429 participants who underwent health checkups at P Hospital in Busan between January 2023 and June 2023. Metabolic syndrome diagnosis was based on the presence of 3 or more risk factors out of the 5 criteria outlined by the American Heart Association/National Heart, Lung, and Blood Institute(AHA/NHLBI), and participants with 2 or fewer risk factors were categorized as normal. Statistical analyses included independent sample t-tests, chi-square tests, Pearson's correlation analysis, Receiver Operating Characteristic(ROC) curve analysis, and logistic regression analysis, using the Statistical Package for the Social Sciences(SPSS) program. Significance was established at p<0.05. The comparison revealed that the metabolic syndrome group exhibited attributes such as advanced age, male gender, elevated systolic and diastolic blood pressures, high blood sugar, elevated triglycerides, reduced LDL-C, elevated HDL-C, higher Cardiometabolic Index, Triglyceride-glucose index, and components linked to abdominal obesity. Pearson correlation analysis showed strong positive correlations between waist circumference/height ratio, waist circumference, Cardiometabolic Index, and triglycerides. Weak positive correlations were observed between LDL-C, body mass index, and Cardiometabolic index, while a strong negative correlation was found between Cardiometabolic Index and HDL-C. ROC analysis indicated that the Cardiometabolic Index(CMI), Triglyceride-glucose(TyG) index, and waist circumference demonstrated the highest Area Under the Curve(AUC) values, indicating their efficacy in diagnosing metabolic syndrome. Optimal cut-off values were determined as >1.34, >8.86, and >84.5 for the Cardiometabolic Index, Triglyceride-glucose index, and waist circumference, respectively. Logistic regression analysis revealed significant differences for age(p=0.037), waist circumference(p<0.001), systolic blood pressure(p<0.001), triglycerides(p<0.001), LDL-C(p=0.028), fasting blood sugar(p<0.001), Cardiometabolic Index(p<0.001), and Triglyceride-glucose index (p<0.001). The odds ratios for these variables were 1.015, 1.179, 1.090, 3.03, and 69.16, respectively. In conclusion, the Cardiometabolic Index and Triglyceride-glucose index are robust predictive indicators closely associated with metabolic syndrome diagnosis, and waist circumference is identified as an excellent predictor. Integrating these variables into clinical practice holds the potential for enhancing early diagnosis and prevention of metabolic syndrome.