• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.87-88
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• 2009

• Tuberculosis and Respiratory Diseases
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• v.67 no.4
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• pp.359-363
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• 2009

Immunoglobulin G4 (IgG4) related autoimmune diseases are characterized by high serum IgG4 concentrations, sclerosing inflammation of numerous IgG4-positive lymphoplasma cells of varying origin, and a positive response to steroid treatment. Autoimmune pancreatitis, sclerosing cholangitis, and retroperitoneal fibrosis are representative presentations of IgG4 related autoimmune disease. Herein, we describe 2 patients (40-years-old woman and 47-years-old man) diagnosed with pulmonary involvement of IgG4-related autoimmune disease. The patients were admitted for an evaluation of the lung mass or multiple lung nodules found on chest radiography. Surgical lung biopsies were performed and pathologic finding revealed lymphoplasmacytic sclerosing inflammation with numerous IgG4 positive cells. The patients had elevated serum total IgG and IgG4 levels. Treatment consisted of high dose methylpredinisolone (1 mg/kg/day) and demonstrated good responsiveness. However, one patient experienced 2 relapses while being tapered off of steroid treatment.

• Tuberculosis and Respiratory Diseases
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• v.78 no.4
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• pp.455-458
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• 2015

Excessive dynamic airway collapse (EDAC) is a disease entity of excessive reduction of the central airway diameter during exhalation, without cartilage collapse. An 80-year-old female presented with generalized edema and dyspnea at our hospital. The patient was in a state of acute decompensated heart failure due to pneumonia with respiratory failure. We accordingly managed the patient with renal replacement therapy, mechanical ventilation and antibiotics. Bronchoscopy confirmed the diagnosis of EDAC. We scheduled extubation after the improvement of pneumonia and heart condition. However, extubation failure occurred due to hypercapnic respiratory failure with poor expectoration. Her EDAC was improved in response to high flow nasal oxygen therapy (HFNOT). Subsequently, the patient was stabilized and transferred to the general ward. HFNOT, which generates physiologic positive end expiratory pressure (PEEP) effects, could be an alternative and effective management of EDAC. Further research and clinical trials are needed to demonstrate the therapeutic effect of HFNOT on EDAC.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.9
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• pp.2744-2751
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• 1996

In case of limited power supply, a rotating shaft system may not reach its operating speed that is greater than its critical speed, but the speed oscillates with small ampllitude near critical speed. As a result, it is considered that the operating mode plays an important role in the smooth start of machines. In order to investigate the dynamic behaviors of the rotating shaft system at the beginning stage, one has derived the equations of motion whose degrees of freedom is three, two translations and one rotation. The simultaneous differential equations are numerically solved by using runge-Kutta method, and thus the small time step length could be required corresponding to the stability of solution. Three types of operating modes dependent upon the driving torque rate have been numerically investigated according to the maximum displacement of shaft center. The first type of relation is linear, the second type is composed of two linear curves recommended by machine manufacturer, and the last one is the proposed torque curve reflecting the frequency response curve of one degree of freedom system. For the second type of modes, it is found that the optimal range of intermediate speed to the critical speed lies between 0.8 and 0.9. In addition to that, the maximum displacement can be reduced more if the third type of mode is utilized.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.2
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• pp.857-880
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• 2016

Due to an increasing number of cyberattacks globally, cybersecurity has become a crucial part of national security in many countries. In particular, the Digital Pearl Harbor has become a real and aggressive security threat, and is considered to be a global issue that can introduce instability to the dynamics of international security. Against this context, the cyberattacks that targeted nuclear power plants (NPPs) in the Republic of Korea triggered concerns regarding the potential effects of cyber terror on critical infrastructure protection (CIP), making it a new security threat to society. Thus, in an attempt to establish measures that strengthen CIP from a cybersecurity perspective, we perform a case study on the cyber-terror attacks that targeted the Korea Hydro & Nuclear Power Co., Ltd. In order to fully appreciate the actual effects of cyber threats on critical infrastructure (CI), and to determine the challenges faced when responding to these threats, we examine factual relationships between the cyberattacks and their responses, and we perform analyses of the characteristics of the cyberattack under consideration. Moreover, we examine the significance of the event considering international norms, while applying the Tallinn Manual. Based on our analyses, we discuss implications for the cybersecurity of CI in South Korea, after which we propose a framework for strengthening cybersecurity in order to protect CI. Then, we discuss the direction of national policies.

• Journal of Neurocritical Care
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• v.11 no.2
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• pp.71-80
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• 2018

Nutritional assessment and support are often overlooked in the critically ill due to other urgent priorities. Unlike oxygenation, organ dysfunction, infection, or consciousness, there is no consensus of indicators. Making it difficult to evaluate the effectiveness of an intervention. Nevertheless, appropriate nutritional support in the critically ill has been associated with less morbidity and lower mortality. But, nutritional support has been considered an adjunct, for body weight maintenance and to help patients during the inflammatory phase of illness. Thus, it has been assigned a lower priority, compared to mechanical ventilation or hemodynamic stability. Recent findings have shown that nutritional support may prevent cellular injury due to oxidative stress and help strengthen the immune response. Large-scale randomized trials and clinical guidelines have shown a shift from nutritional support to nutritional therapy, with an emphasis on the importance of protein, minerals, vitamins, and trace elements. Nutrition is also important in neurocritically ill patients. Since there are few studies or recommendations with regard to the neurocritical population, the general recommendations for nutritional support should be applied.

• Food Engineering Progress
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• v.21 no.2
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• pp.132-137
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• 2017

The purpose of this study was to optimize dough properties using response surface methodology (RSM) and to demonstrate the performances of dough prepared under optimized conditions. Dough mixed with yeast, margarine, salt, sugar and wheat flour was prepared by fermentation process. Hardness, cohesiveness and springiness of dough were selected as critical quality attributes. The critical formulations (yeast and water) and process (fermentation time) variables were selected as critical input variables based on preliminary experiment. Box-Behnken design (BBD) was used as RSM. As a result, the quardratic, the squared and the linear model respectively provided the most appropriate fit ($R^2$>90) and had no significant lack of fit (p>0.05) on critical quality attributes (hardness, cohesiveness and springiness). The accurate prediction of dough characteristics was possible from the selected models. It was confirmed by validation that a good correlation was obtained between the actual and predicted values. In conclusion, the methodologies using RSM in this study might be applicable to the optimization of fermented foods containing various wheat flour and yeast.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.4
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• pp.673-679
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• 2013

This study investigates the strength durability of an automotive front bumper subjected to vibrations during driving. Through structural analyses,the maximum equivalent stresses of models 1 and 2 were found to be 187.09 and 278.4 MPa, respectively. The maximum deformations of models 1 and 2 were 1.3772 and 2.675 mm, respectively. As model 1 shows less deformation than model 2, itis stronger than model 2. Models 1and 2 show natural frequencies within 230 Hz as the range of the maximum harmonic response frequency. Models 1 and 2 have maximum amplitude displacements of 0.105 and 0.154 mm at critical frequencies of 159 and 110 Hz, respectively. As model 1 has a higher critical frequency than model 2, it has more strength durability than model 2. This study result can be effectively utilized for the design of a front bumper by investigating prevention against damage and its strength durability.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.4
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• pp.69-74
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• 2013

According to the axial torsion applied at power transmission and the vibration from the roughness of road surface, this paper analyzes the stresses on two kinds of universal joint model. As stress and deformation at model 2 becomes smaller than model 1 on structural analysis, model 2 is more stabilized than model 1. The natural frequencies at model 1 and 2 are 7,040 and 9,540 Hz respectively. As the natural frequency range of model 2 becomes higher than model 1, model 2 becomes safer than model 1. Critical frequencies at these models are calculated through harmonic response analyses. On critical frequencies at model 1 and 2, the stress at model 2 becomes lower than 2 times as much as model 1 and the deformation at model 2 becomes lower than 4 times as much as model 1. Model 2 on durability is thought to become better than model 1. This study result is applied with the design of safe universal joint and it can be useful to improve the durability by predicting prevention against the deformation due to its vibration.

• Structural Engineering and Mechanics
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• v.34 no.6
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• pp.755-778
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• 2010

Near-fault ground motion with directivity or fling effects is significantly influenced by the rupture mechanism and substantially different from ordinary records. This class of ground motion has large amplitude and long period, exhibits unusual response spectra shapes, possesses high PGV/PGA and PGD/PGA ratios and is best characterized in the velocity and the displacement time-histories. Such ground motion is also characterized by its energy being contained in a single or very few pulses, thus capable of causing severe damage to the structures. This paper investigates the characteristics of near-fault pulse-like ground motions and their implications on the structural responses using new proposed measures, such as, the effective frequency range, the energy rate (in time and frequency domains) and the damage indices. The paper develops also simple mathematical expressions for modeling this class of ground motion and the associated structural responses, thus eliminating numerical integration of the equations of motion. An optimization technique is also developed by using energy concepts and damage indices for modeling this class of ground motion for inelastic structures at sites having limited earthquake data.