• Journal of Trauma and Injury
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• v.23 no.2
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• pp.57-62
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• 2010

Purpose: This study analyzed the characteristics of stable pelvic bone fractures with intra-abdominal solid organ injury. Methods: Medical records were retrospectively reviewed from January 2000 to December 2009 of patients with stable pelvic bone fractures. A stable pelvic bone fracture according to Young's classification is defined as a lateral compression type I and antero-posterior compression type I. Subjects were divided into two groups, one with (injured group) and one without (non-injured group) intra-abdominal solid organ injury, to evaluate the dependences of the characteristics on the presence of an intra-abdominal solid organ injury. Data including demographics, mechanism of injury, initial hemodynamic status, laboratory results, Revised Trauma Score (RTS), Abbreviated Injury Scale (AIS), Injury Severity Score (ISS), amount of transfusion, admission to intensive care unit (ICU), and mortality were analyzed. Results: The subjects were 128 patients with a mean age of 42 years old, of whom were 67 male patients (52.3%). The injured group had 21 patients(16.4%), and the most frequent injured solid organ was the liver. Traffic accident was the most common mechanism of injury and lateral compression was the most common type of fracture in all groups. Initial systolic blood pressure was lower in the injured group, and the ISS was greater in the injured group. Arterial pH was lower in the injured group, and shock within 24 hours after arrival at the emergency department was more frequent in the injured group. Transfused packed red blood cells within 24 hours were 8 patients(38.1%) in the injured group and 11 patients(10.3%) in the non-injured group. Conservative treatment was the most common therapeutic modality in all groups. Stay in the ICU was longer in the injured group, and three mortalities occurred. Conclusion: There is a need to decide on a diagnostic and therapeutic plan regarding the possibility of intra-abdominal solid organ injury for hemodynamically unstable patients with stable pelvic bone fractures and for patients with stable pelvic bone fractures along with multiple associated injuries.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.3
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• pp.171-176
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• 2021

Pneumomediastinum is a very rare and potentially catastrophic complication of dental procedures. Its common causes are tooth extraction, endodontic treatment, and subgingival curettage using handpieces and high-pressure air/water syringes. We present a case of massive pneumomediastinum with subcutaneous emphysema in a 61-year-old female who underwent bone grafting into the maxilla for pretreatment of dental implantation using a syringe. The patient suffered from abrupt severe odynophagia and loss of consciousness. The patient transferred to emergency department and images work-up revealed a pneumomediastinum and subcutaneous emphysema on the entire face and neck. We performed conservative treatments including prophylactic antibiotics, oxygen inhalation, and fasting meals, and then discharge after 7 days uneventfully. The patient's syncope might be resulting from hypotension and pain shock induced by pneumomediastinum with a sudden chest compression. The pneumomediastinum could be resulting from concurrent perforation and massive air infiltration into the maxillary sinus during bone grafting. We suggest that pneumomediastinum needs prompt diagnosis and management because of the risk of airway obstruction when a patient present syncope in the dental room.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.642-648
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• 2019

This paper presents a fast back-type transfer device for snack food processing that uses the inertia of transferred material. A conventional conveying system is a drive system that uses a belt conveyor and mechanical crank, which generate noise and vibration and cause environmental pollution. Vibration and noise are reduced in the proposed fast back feeding device by using a counterweight. The crank drive unit was replaced with a linear servomotor, and an equilibrium device was designed to balance the force due to acceleration. This makes it is possible to adjust the forward and backward speed and acceleration through PLC control. A vibration damper device offsets the vibration force of the periodic shock form. The main cause of the vibration was identified through vibration analysis, and reduction measures were established. We verified the effectiveness of the vibration by making a prototype and performing about 10 vibration tests. Because no mechanical transducer is needed, energy loss, noise, and vibration do not occur, and the operating speed is not limited.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.384-395
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• 2020

Breaking waves generated by wave shoaling in coastal areas have a close relationship with various physical phenomena in coastal regions, such as sediment transport, longshore currents, and shock wave pressure. Therefore, it is crucial to accurately predict breaker index such as breaking wave height and breaking depth, when designing coastal structures. Numerous scientific efforts have been made in the past by many researchers to identify and predict the breaking phenomenon. Representative studies on wave breaking provide many empirical formulas for the prediction of breaking index, mainly through hydraulic model experiments. However, the existing empirical formulas for breaking index determine the coefficients of the assumed equation through statistical analysis of data under the assumption of a specific equation. In this paper, we applied a representative linear-based supervised machine learning algorithms that show high predictive performance in various research fields related to regression or classification problems. Based on the used machine learning methods, a model for prediction of the breaking index is developed from previously published experimental data on the breaking wave, and a new linear equation for prediction of breaker index is presented from the trained model. The newly proposed breaker index formula showed similar predictive performance compared to the existing empirical formula, although it was a simple linear equation.

• Journal of Korean Society of Disaster and Security
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• v.16 no.1
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• pp.61-70
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• 2023

This study presents an analytical study of investigating the effect of shock waves generated by the hydrogen detonation and damage to structures for the safety evaluation of hydrogen storage facilities against detonation. Blast scenarios were established considering the volume of the hydrogen storage facility of 10 L to 50,000 L, states of charge (SOC) of 50% and 100%, and initial pressures of 50 MPa and 100 MPa. The equivalent TNT weight for hydrgen detonation was determined considering the mechanical and chemical energies of hydrogen. A hydrogen detonation model for the converted equivalent TNT weight was made using design equations that improved the Kingery-Bulmash design chart of UFC 3-340-02. The hydrogen detonation model was validated for overpressure and impulse in comparison to the past experimental results associated with the detonation of hydrogen tank. A parametric study based on the blast scenarios was performed using the validated hydrogen detonation model, and design charts for overpressure and impulse according to the standoff distance from the center of charge was provided. Further, design charts of the three-stage structural damage and standoff distance of adjacent structures according to the level of overpressure and impact were proposed using the overpressure and impulse charts and pressure-impulse diagrams.

• Economic Analysis
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• v.25 no.2
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• pp.132-176
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• 2019

We use a time-varying parameter vector auto regression (TVP-VAR) model to understand the impact of U.S. monetary policy normalization on Korean financial markets and capital accounts. The U.S. monetary policy is represented by the federal funds rate, term premium and credit spread. During the U.S. monetary contraction period of 2004 to 2006, changes in the federal funds rate presented negative pressure on Korean financial markets. The changes in federal funds rate also led to a simultaneous contraction in inward and outward capital flows. However, the effects of a federal funds rate shock has been reduced since 2015. On the other hand, the effects of U.S. term premiums is getting stronger after the period of quantitative easing (QE). The influence of the U.S. credit spread also significantly increased after the global financial crisis. Simulation results show that a rise in the U.S. credit spread, which can be triggered by a contractionary monetary policy, can pose a larger adverse impact on the Korean economy than a rise in the federal funds rate itself. As for capital flows, a U.S. monetary policy contraction causes an outflow of foreign investment, but the repatriation of overseas investment by Korean residents can offset this outflow.

• Tuberculosis and Respiratory Diseases
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• v.65 no.4
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• pp.292-300
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• 2008

Background: Respiratory failure is a common condition that requires intensive care, and has a high mortality rate despite the recent improvements in respiratory care. Previous reports of patients with respiratory failure focused on the specific disease or included a large proportion of surgical patients. This study evaluated the clinical characteristics, outcomes and prognostic factors of adult patients receiving mechanical ventilation in a medical intensive care unit. Methods: Retrospective chart review was performed on 479 adult patients, who received mechanical ventilation for more than 48 hours in the medical ICU of one tertiary referral hospital. Results: The mean age of the patients was $60.3{\pm}15.6$ years and 34.0% were female. The initial mean APACHE III score was $72.3{\pm}25$. The cause of MV included acute respiratory failure (71.8%), acute exacerbation of chronic pulmonary disease (20.9%), coma (5.6%), and neuromuscular disorders (1.7%). Pressure controlled ventilation was used as the initial ventilator mode in 67.8% of patients, and pressure support ventilation was used as the initial weaning mode in 83.6% of the patients. The overall mortality rate in the ICU and hospital was 49.3% and 55.4%, respectively. The main cause of death in hospital was septic shock (32.5%), respiratory failure (11.7%), and multiorgan failure (10.2%). Males, an APACHE III score >70, the cause of respiratory failure (interstitial lung disease, coma, aspiration, pneumonia, sepsis and hemoptysis), the total ventilation time, and length of stay in hospital were independently associated with mortality. Conclusion: The cause of respiratory failure, severity of the patients, and gender appears to be significantly associated with the outcome of mechanical ventilatory support in patients with respiratory failure.

• Journal of Chest Surgery
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• v.31 no.9
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• pp.827-836
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• 1998

Background: Effective cardiopulmonary resuscitation (CPR) should provide acceptable hemodynamics for the vital organs during cardiac arrest and early restoration of spontaneous circulation that guarantees long-term, neurologically intact survival. CPR using heart-lung bypass has been suggested as an option for that use. This study was designed to determine the effectiveness of standard CPR techniques, closed-vs. open-chest CPR, which could be used in the future study verifying the role of heart-lung bypass CPR. Material and Method: By using adult mongrel dogs, closed-chest CPR (CCCPR, n=4) and open-chest CPR (OCCPR, n=5) were compared with respects to hemodynamics, restoration of spontaneous circulation(ROSC), and survival. Ventricular fibrillation-cardiac arrest (VF-CA) was induced by electrical shock in all animals. After 4 minutes of cardiac arrest, basic life support (BLS) was applied for 15 minutes and followed by advanced life support (ALS). ALS was maintained until achi ving ROSC but not longer than 30 minutes regardless of the recovery. Resuscitation procedures in either group were standardized by adopting the protocol of American Heart Association. Result: Prearrest baseline hemodynamic data was not different between two groups. During resuscitation, substantially higher systolic pressure was maintained in OCCPR group than in CCCPR group (45$\pm$15 vs. 33$\pm$11 mmHg during BLS, 83$\pm$36 vs. 44$\pm$15 mmHg during ALS; p=NS). Mean pulmonary arterial pressure went up to the level of mean systemic arterial pressures in CCCPR group and to half of that in OCCPR group, and had kept higher in CCCPR group throughout CPR (32$\pm$10 vs. 22$\pm$4 mmHg during BLS and 32$\pm$15 vs. 24$\pm$10 mmHg during ALS; p=NS). ROSC was obtained in 4 of 5 dogs receiving open-chest CPR and 2 of 4 closed-chest CPR. Prolonged survival was noted in all dogs in OCCPR group (6 to 1440 hours) but not in CCPR group (p<.05). Conclusion: These findings indicate that open-chest CPR can be more effective t maintain hemodynamics during cardiac arrest and to obtain restoration of spontaneous circulation and survival. Further experiment will be designed to compare heart-lung bypass CPR with open-chest CPR.

• Journal of the Korean earth science society
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• v.23 no.4
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• pp.357-368
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• 2002

In this study we have tried to explain the barrel-shaped morphology for young supernova remnants considering the dynamical effects of the ejecta. We consider the magnetic field amplification resulting from the Rayleigh-Taylor instability near the contact discontinuity. We can generate the synthetic radio image assuming the cosmic-ray pressure and calculate the azimuthal intensity ratio (A) to enable a quantitative comparison with observations. The postshock magnetic field are amplified by shearing, stretching, and compressing at the R-T finger boundary. The evolution of the instability strongly depends on the deceleration of the ejecta and the evolutionary stage of the remnant. the strength of the magnetic field increases in the initial phase and decreases after the reverse shock passes the constant density region of the ejecta. However, some memory of the earlier phases of amplification is retained in the interior even when the outer regions turn into a blast wave. The ratio of the averaged magnetic field strength at the equator to the one at the pole in the turbulent region can amount to 7.5 at the peak. The magnetic field amplification can make the large azimuthal intensity ratio (A=15). The magnitude of the amplification is sensitive to numerical resolution. This mens the magnetic field amplification can explain the barrel-shaped morphology of young supernova remnant without the dependence of the efficiency of the cosmic-ray acceleration on the magnetic field configuration. In order for this mechanism to be effective, the surrounding magnetic field must be well-ordered. The small number of barrel-shaped remnants may indicate that this condition rarely occurs.