• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.6-11
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• 2005

During the acceptance test of KTX, lateral vibration of carbody at the tail of the train was found. The carbody lateral vibration was occurred on a straight line in the winter season. We analysis to find the cause of the lateral vibration and the countermeasure. The analysis results show that lateral stiffness of air spring is the most important parameter to cause the carbody lateral vibration. The lateral vibration is occurred at frequency range $0.5{\sim}0.6Hz$ with a negative damping value. We also blow that natural frequency of lateral vibration increase with the train speed up to 1Hz at 300km/h.

• Toxicological Research
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• v.21 no.3
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• pp.195-208
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• 2005

Diabetes is a major cause of morbidity and mortality, and associated with a high risk of atherosclerosis, and liver, kidney, nerve and tissue damage. Defective insulin secretion in pancreas and/or insulin resistance in peripheral tissues is a central component of diabetes. It is well established that, regardless of the degree of muscle insulin resistance, glucose levels in diabetic and non-diabetic individuals are determined by the rate of hepatic glucose production. Moreover recently studies using liver-specific insulin receptor knockout mice show the paramount role of the liver in insulin resistance and diabetes. Insulin exerts a multifaceted and highly integrated series of actions via its intracellular signaling systems. The first major section of this review defines the major insulin-mediated signaling pathways including phosphatidylinositol 3-kinase and mitogen activated protein kinases. The second major section of the review presents a summary and evaluation of methods for determination of the role and function of signaling pathways, including methods for determination of kinase phosphorylation, the use of pharmacological inhibitors of kinase and dominant-negative kinase constructs, and the application of new RNA interference methods.

• Journal of Power Electronics
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• v.19 no.5
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• pp.1142-1152
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• 2019

This paper presents a control method for reducing the current distortion in an indirect matrix converter (IMC) operating in boost mode under unbalanced input conditions. IMCs operating in boost mode are useful in distributed generation (DG) systems. They are connected with renewable energy systems (RESs) and the grid to transmit the power generated by the RES. However, under unbalanced voltage conditions of the RES, which is connected with the input stage of the IMC operating in boost mode, the input-output currents are distorted. In particular, the output current distortions cause a ripple of the power, which is transferred to the grid. This aggravates the reliability and stability of the DG system. Therefore, in this paper, a control method using positive/negative sequence voltages and currents is proposed for reducing the current distortion of both side in IMCs operating in boost mode. Simulation and experimental results have been presented to validate effectiveness of the proposed control method.

• Journal of Advanced Research in Ocean Engineering
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• v.2 no.1
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• pp.12-21
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• 2016

In this paper, the $2^{nd}$ order hydrodynamic force effect of heaving submerged circular cylinder is considered, with the linear potential theory. Boundary value problem (BVP) is expanded up to the $2^{nd}$ order by using of the perturbation method and the $2^{nd}$ order velocity potential is calculated by means of integral equation technique using the classical Green's function expressed in cylindrical coordinates. The method of solving BVP is based on eigenfunction expansions. With different cylinder heights and heaving frequencies, graphical results are presented. As a result of the study, the cause of oscillatory force pattern is analyzed with the occurrence of negative added mass when a top of the cylinder gets closer to the free surface.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.22 no.6
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• pp.576-580
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• 2019

Meconium peritonitis as a cause of non-immune hydrops in neonates is rarely reported. Here we report such a rare occurrence. In our case, a routine antenatal scan at 25 weeks revealed isolated ascites. By 31 weeks of gestation, all features of hydrops were observed in scans. However, antenatal workup for immune and non-immune hydrops was negative. Subsequently, a preterm hydropic female baby was delivered at 32 weeks. She required intubation and ventilator support. An X-ray revealed calcification in the abdomen suggestive of meconium peritonitis. Ultrasound showed gross ascites, a giant cyst compressing the inferior vena cava, and minimal bilateral pleural effusion. Emergency laparotomy revealed meconium pellets and perforation of the ileum. Double-barrel ileostomy was performed, and the edema resolved and activity improved. The baby was discharged after 3 weeks. Ileostomy closure was done at follow-up. The baby is growing well.

• Proceedings of the KIEE Conference
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• 2005.10c
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• pp.270-272
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• 2005

With the wide spread of direct current (DC) electric railroads in Korea, the stray currents from negative return rails become a pending problem to the safety of nearby underground infrastructures, such as gas pipelines, water distribution lines, heat pipelines, POF cables, etc. The mitigation of such interference, however, is mainly dependent on stray current drainage bond methods, which connect the underground metallic structures to the negative feeder cables attached to the rails with diodes (polarized drainage) or thyristors (forced drainage). Despite some merits of these methods, they increase the total amount of stray currents from rails and cause other interference problems. In this paper, we summarize the domestic conditions of stray current interference and describe a conceptual design of other mitigation methods for such interference.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04a
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• pp.27-30
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• 2004

Different types of hybrid negative materials on pitch based carbon and natural graphite for lithium ion batteries were studied. Two types of active materials were prepared, that is, pitch based graphite carbon, and pitch based carbon impregnating natural graphite. The specific capacity, capacity recovery in high temperature condition, and other electrochemical properties were achieved for these materials. We found that addition of natural graphite type to the pitch based carbon can significant1y improve the specific capacity and interfacial resistance. However, use of natural graphite will cause a serious capacity loss in the high temperature condition owing to its increasing interface resistance. The specific capacity ranged from 321 to 348 mAh/g and the maximum specific capacity was obtained in the case of pitch based carbon impregnating natural graphite.

• Journal of the Korean School Mathematics Society
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• v.5 no.1
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• pp.1-11
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• 2002

The purpose of this study is to find out if there are meaningful differences between small rural middle schools and nearby urban ones In the mathematical diagnostic evaluation. It also says how to improve students' scholastic abilities, making up a question of attitudes towards math to know the mathematical abilities lowering cause in small rural middle schools. Findings are, 1. Students must recognize that studying math is essential and be interested in it. 2. The mathematical confidence is needed. 3. A strong will of studying math hard is important. 4. Students must have a motivational triggering, while solving math problems and then checking answers for themselves. 5. Backward countries' humanistic and social environmental factors should be overcome. In conclusion, we expect the mathematical abilities improvement, making students remove the mathematical abilities lowering cause after having a learning experience suitable for the rural community instead of the negative attitudes towards math.

• Journal of Haehwa Medicine
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• v.13 no.1
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• pp.345-353
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• 2004

This study analyzed the contents of the research papers concerning the obesity from a psychiatrical point of view. As a result, the following conclusion was drawn. 1. In obese people, negative emotions, especially depression were frequently reported. 2. Negative feelings, especially anger, anxiety, depression, induce binge eating and can lead to obesity. 3. Depression was related to the wrong body image more than to the body mass index. 4. Wrong body image affects eating attitudes, which may cause eating disorders. 5. To treat obesity or eating disorders, we must use psychosocial treatment, for example, supportive, cognitive or behavior therapy.

• Journal of the Ergonomics Society of Korea
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• v.15 no.2
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• pp.185-192
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• 1996

EEG(electroencephalogram) is characterized with auditory emotion in this study. Twenty university students participated in this study. The auditory stimulus was the natural sounds such as creek sound, clash, machining noise, and etc. They can cause the positive and negative emotion. EEG characteristics according to positive and negative auditory stimuli is tried to observe statistic difference. The significant difference is shown depending on the localized area. The auditory paraameters of EEG variation is examined for defining human emotion qualitatively. The results shows that the alpha and the beta at temproal area may be thd determinat of human auditory emotion.