• Bulletin of the Korean Mathematical Society
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• v.52 no.2
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• pp.395-408
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• 2015

In present article, we determine the distinguishing number of the merged Johnson graphs which are generalization of both the Kneser graphs and the Johnson graphs.

• Journal of Yeungnam Medical Science
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• v.19 no.1
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• pp.68-72
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• 2002

Dubin-Johnson syndrome is a form of benign, familial idiopathic jaundice presenting with chronic intermittent conjugated hyperbilirubinemia and a melanin-like pigment has been found in the parenchymal liver cells. This disorder is rarely diagnosed in the neonatal period. We report a case of Dubin-Johnson syndrome presenting with neonatal cholestasis.

• The Korean Journal of Applied Statistics
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• v.37 no.1
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• pp.39-48
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• 2024

In this paper, we introduce an extended GARCH model designed to address asymmetric leverage effects. The variance in the standard GARCH model is composed of past conditional variances and past squared residuals. However, it is not possible to model asymmetric leverage effects with squared residuals alone, so in this paper, we propose a new extended GARCH model to explain the leverage effects using the Yeo-Johnson transformation which adjusts transformation parameter to make asymmetric data more normal or symmetric. We utilize the reverse properties of Yeo-Johnson transformation to model asymmetric volatility. We investigate the characteristics of the proposed model and parameter estimation. We also explore how to derive forecasts and forecast intervals in the proposed model. We compare it with standard GARCH and other extended GARCH models that model asymmetric leverage effects through empirical data analysis.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.1860-1862
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• 1998

This Paper presents a novel resonant switching Watkins-Johnson DC-DC converters. In the proposed converters, the basic steady-state analysis of the have been presented for the ZVS type Watkins-Johnson converter. From the results, it is shown that the output voltage of the converter is independant of load resistance, and is determined only by the switching frequency. Consequently, a design procedure is presented that minimizes voltage stress to the switch while maintaining ZVS for all loads.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.960-961
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• 2006

In this paper, a static var compensator using three phase PWM Watkins-Johnson AC-AC converter is presented. The PWM Watkins-Johnson AC-AC converter is modelled by using circuit DQ transformation whereby the basic DC characteristics equation is analytically obtained. Finally, the PSIM simulation shows the validity of the modelling and analysis.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.119-121
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• 2005

In this paper, a three phase PWM Watkins-Johnson AC-AC converter for VVCF applications is presented. The PWM Watkins-Johnson AC-AC converter is modelled by using vector DQ transformation whereby the basic DC characteristics equation is analytically obtained. Finally, the PSIM simulation shows the validity of the modelling and analysis.

• Clinical and Experimental Pediatrics
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• v.52 no.2
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• pp.247-250
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• 2009

Stevens-Johnson syndrome (SJS) presents with widespread blisters, erythematous or purpuric macules, and one or more mucous membrane erosions. Various etiologic factors, including infection, vaccination, drug administration, systemic diseases, physical agents, and food have been implicated as causes of SJS. Mycoplasma pneumoniae is the most common infectious agent to cause SJS in children. In recent literature, M. pneumoniae-induced SJS with mucositis that lacks the typical target lesions has been described. We report a case of a 6-year-old boy with swelling, peeling of the lips, and red eyes with photosensitivity. On physical examination, he showed severe oral mucositis and conjunctivitis with no evidence of skin lesions. Mycoplasma antibody, which was positive with titers of more than 1:2,560. For patients presenting with fever and mucositis of unknown origin, M. pneumoniae should be considered.

• The Korean Journal of Applied Statistics
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• v.25 no.1
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• pp.29-43
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• 2012

Financial data such as stock index returns and exchange rates have the properties of heavy tail and asymmetry compared to normal distribution. When we estimate VaR using the GARCH model (with the conditional return distribution of normal) it shows the tendency of the lower estimation and clustering in the losses over the estimated VaR. In this paper, we argue that this problem can be resolved through the adaptation of the unbounded Johnson distribution as that of the condition return. We also compare this model with the GARCH with the conditional return distribution of normal and student-t. Using the losses exceed the ex-ante VaR, estimates, we check the validity of the GARCH models through the failure proportion test and the clustering test. We nd that the GARCH model with conditional return distribution of unbounded Johnson provides an appropriate estimation of the VaR and does not occur the clustering of violations.

• Journal of Aerospace System Engineering
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• v.17 no.5
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• pp.19-27
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• 2023

In this study, we used finite element analysis to conduct a containment capability evaluation of a turbine case. When analyzing the impact behavior of structures subjected to impact loads, it is important to consider the strain rate, as it affects the increase in flow stress. Therefore, we applied three material models (Cowper-Symonds, Johnson-Cook, and Modified Johnson-Cook) for the impact analysis. To validate these material models, we performed an impact test on an aluminum 6061 plate. By comparing and analyzing the experimental and analytical results, we determined that the Modified Johnson-Cook material model exhibited the least error. As a result, we applied this material model to evaluate the containment capability of the turbine case. This evaluation involved determining the occurrence of penetration, as well as the stress and strain induced at the collision area due to the initial velocity of the blade.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.925-926
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• 2012