• Journal of Korean Society for Geospatial Information Science
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• v.25 no.1
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• pp.37-46
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• 2017

Recently, disaster caused by social factors is frequently occurring in Korea. Prediction about what crisis could happen is difficult, raising the citizen's concern. In this study, we developed a program to acquire tweet data by applying Python language based Tweepy plug-in, regarding social disasters such as 'Nonspecific motive crimes' and 'Oxy' products. These data were used to evaluate psychological trauma and anxiety of citizens through the text clustering analysis and the opinion mining analysis of the R Studio program after natural language processing. In the analysis of the 'Oxy' case, the accident of Sewol ferry, the continual sale of Oxy products of the Oxy had the highest similarity and 'Nonspecific motive crimes', the coping measures of the government against unexpected incidents such as the 'incident' of the screen door, the accident of Sewol ferry and 'Nonspecific motive crime' due to misogyny in Busan, had the highest similarity. In addition, the average index of the Citizens sentiment score in Nonspecific motive crimes was more negative than that in the Oxy case by 11.61%p. Therefore, it is expected that the findings will be utilized to predict the mental health of citizens to prevent future accidents.

• Korean Journal of Psychosomatic Medicine
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• v.29 no.2
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• pp.136-143
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• 2021

Objectives : The coronavirus disease 2019 (COVID-19) outbreak is a global medical crisis imposing particular burden on public sector employees. The aim of this study was to investigate the psychiatric distress among public sector workers amid the COVID-19 pandemic. Methods : We conducted a cross-sectional study with 531 public sector workers in Gwangmyung city who completed Korean versions of the Perceived Stress Scale (PSS), Patient Health Questionnaire-9 (PHQ-9), and Impact of Event Scale-Revised-Korean (IES-R-K). Results : The results revealed more than moderate levels of stress (85.2%), depressive symptoms (22.2%), and posttraumatic stress symptoms (38.8%). PSS total score was significantly correlated with PHQ-9, IES-R-K total scores as well as IES-R-K subscale scores. Total scores on the PSS, PHQ-9, and IES-R-K were all inversely correlated with age. Conclusions : COVID-19-related workers experience considerable stress and depressive symptoms, with self-rated stress correlating significantly with depression scores. Age may serve as a protective factor against occupational stress and burnout. These findings highlight the need for adequate psychiatric screening and intervention for public sector workers.

• Journal of Korea Port Economic Association
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• v.39 no.1
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• pp.115-129
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• 2023

This study analyzed the risk spillover of BDI on shipping company stock prices through the Copula-CoVaR method based on daily data from January 4, 2010, to October 31, 2022. The main empirical analysis results and policy implications are as follows. First, copula results showed that there was a weak dependence between BDI and shipping company stock prices, and PAN, KOR, and YEN were selected as the most fitting model for dynamic Student-t copula, HMM was selected as the rotated Gumbel copula, and KSS was selected as the best model. Second, in the results of CoVaR, it was confirmed that the upside (downside) CoVaR was significantly different from the upside (downside) VaR in all shipping companies. This means that BDI has a significant risk spillover on shipping companies. In addition, as for the risk spillover, the downside risk is generally lower than the upside risk, so the downside and upside risk spillover were found to be asymmetrical. Therefore, policymakers should strengthen external risk supervision and establish differentiated policies suitable for domestic conditions to prevent systematic risks from BDI shocks. And investors should reflect external risks from BDI fluctuations in their investment decisions and construct optimal investment portfolios to avoid risks. On the other hand, investors propose that the investment portfolio should be adjusted in consideration of the asymmetric characteristics of up and down risks when making investment decisions.

• Journal of the Economic Geographical Society of Korea
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• v.26 no.3
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• pp.289-309
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• 2023

While South Korea's universal healthcare system has garnered attention in public health, the issue of inequality in healthcare service provision among different age groups has incessantly become a significant concern. The focus of this concern is primarily on essential healthcare services, encompassing fundamental aspects of healthcare such as internal medicine, family medicine, and pediatric and adolescent care. This inequality is not limited to differences among age groups (both junior and senior demographics) but also extends to potential disparities in healthcare services based on geographic location, particularly in urban and rural contexts. This paper aims to investigate disparities in primary healthcare service resources in South Korea's evolving economic landscape between 1995 and 2021. We utilize a set of inequality indices with a spatial perspective through geographic cluster analysis. The findings reveal that concerns about inequality have been amplified during various economic events, including the IMF crisis in 1999, the global financial crisis in 2008, and the COVID-19 pandemic in 2020. These years are identified as significant phases that have contributed to manifesting spatial disparities in primary healthcare provisions, with a particular emphasis on the senior-aged population rather than junior or all population groups. Our findings underscore the pressing need to address the unequal distribution of essential healthcare resources as part of preparedness for potential economic impacts, requiring a comprehensive consideration of the interconnected nature of demographic and spatial dimensions in healthcare services.

• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.101-109
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• 2005

Background: In sudden cardiac arrest, the effective maintenance of coronary artery blood flow is of paramount importance for myocardial preservation as well as cardiac recovery and patient survival. The purpose of this study was to directly compare the effects of pulsatile and non-pulsatile circulation to coronary artery flow and myocardial preservation in cardiac arrest condition. Material and Method: A cardiopulmonary bypass circuit was constructed in a ventricular fibrillation model using fourteen Yorkshire swine weighing $25\~35$ kg each. The animals were randomly assigned to group I (n=7, non-pulsatile centrifugal pump) or group II (n=7, pulsatile T-PLS pump). Extra-corporeal circulation was maintained for two hours at a pump flow of 2 L/min. The left anterior descending coronary artery flow was measured with an ultrasonic coronary artery flow measurement system at baseline (before bypass) and at every 20 minutes after bypass. Serologic parameters were collected simultaneously at baseline, 1 hour, and 2 hours after bypass in the coronary sinus venous blood. The Mann-Whitney U test of STATISTICA 6.0 was used to determine intergroup significances using a p value of < 0.05. Result: The resistance index of the coronary artery was lower in group II and the difference was significant at 40 min, 80 min, 100 min and 120 min (p < 0.05). The mean velocity of the coronary artery was higher in group II throughout the study, and the difference was significant from 20 min after starting the pump (p < 0.05). The coronary artery blood flow was higher in group II throughout the study, and the difference was significant from 40 min to 120 min (p < 0.05) except at 80 min. Serologic parameters showed no differences between the groups at 1 hour and 2 hours after bypass in the coronary sinus blood. Conclusion: In cardiac arrest condition, pulsatile extracorporeal circulation provides more blood flow, higher flow velocity and less resistance to coronary artery than non-pulsatile circulation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.601-606
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• 1999

Physiological responses of cultured olive flounder (Paralichthys olivaceus) on lowering seawater temperature sharply and continuously were studied with 4 experiments of temperature changes (Exp.I$\~$IV). In Exp.1, the temperature was decreased from $18^{\circ}C$ to $9^{\circ}C$ by the rate of $1^{\circ}C$/hr, thereafter back to the initial temperature after 5 dars. With the same conditions of temperature rate and 5 days interval, the temperature changes for Exp.II, III and IV were $20^{\circ}C$ to $17^{\circ}C,\;23^{\circ}C$ to $14^{\circ}C$ and $23^{\circ}C$ to $17^{\circ}C$, respectively, Serum cortisol and glucose were measured during whole experiments. Hematocrit (Ht), hemoglobin (Hb), red blood cell (RBC) and mean corpuscular hemoglobin concentration (MCHC) were measured in the Exp.I, and osmolality, electrolytes ($Na^+,\;Cl^-,\;K^+,\;Ca^{2+}$), total protein, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) of serum, in Exp.II$\~$IV. Serum cortisol levels were significantly increased by the lowering temperature sharply during whole experiments, while serum glucose levels were increased only in Exp,III and IV. Ht, RBC and Hb were decreased as the water temperature was lowered, but MCHC was increased. The serum osmolality was reduced and the unstable changes of electrolytes were shown by the changes of seawater temperature. No significant changes in total protein, ALT and AST activity were observed.

• The Journal of the Acoustical Society of Korea
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• v.42 no.6
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• pp.603-616
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• 2023

In this study, machine learning-based clustering and classification of residential noise in apartment buildings was conducted using frequency and temporal characteristics. First, a residential noise source dataset was constructed . The residential noise source dataset was consisted of floor impact, airborne, plumbing and equipment noise, environmental, and construction noise. The clustering of residential noise was performed by K-Means clustering method. For frequency characteristics, L_eq and L_max values were derived for 1/1 and 1/3 octave band for each sound source. For temporal characteristics, Leq values were derived at every 6 ms through sound pressure level analysis for 5 s. The number of k in K-Means clustering method was determined through the silhouette coefficient and elbow method. The clustering of residential noise source by frequency characteristic resulted in three clusters for both L_eq and L_max analysis. Temporal characteristic clustered residential noise source into 9 clusters for L_eq and 11 clusters for L_max. Clustering by frequency characteristic clustered according to the proportion of low frequency band. Then, to utilize the clustering results, the residential noise source was classified using three kinds of machine learning. The results of the residential noise classification showed the highest accuracy and f1-score for data labeled with L_eq values in 1/3 octave bands, and the highest accuracy and f1-score for classifying residential noise sources with an Artificial Neural Network (ANN) model using both frequency and temporal features, with 93 % accuracy and 92 % f1-score.

• Journal of Animal Environmental Science
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• v.6 no.3
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• pp.175-184
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• 2000

A lab-scale MF membrane reactor was installed to investigate the membrane permeability, characteristics of membrane fouling at each conditions, and quality of permeate (liquid livestock manure) in the separation of solid-matters using membrane. Experiment was divided three filtration type such as follows; continuous filtration, gravity filtration, and intermittent filtration. As a result of experiment, flux 1 LMH was maintained for 7days, and trans-membrane pressure(TMP) was increased gradually under 10cmHg, but it was increased immediately after 10cmHg, respectively. However, the flux was increased, the Tmax was decreased exponential more and more. During the pure-flux test, most of the fouling of membrane was reversible. At the gravity filtration, permeate could be obtained as 1.75 LMH for 3.5days without any other electronic pressure. As an investigation of membrane surface, this study could be decided that the reason of fouling at the lower flux (Run 1 and 2) was attached matters in membrane surface, but at the higher flux (Run 4-6) was concentration polarization.