• Journal of the Korean Data and Information Science Society
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• v.25 no.6
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• pp.1581-1589
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• 2014

In this paper, we consider maximum likelihood estimators of the location and scale parameters for the half-logistic distribution when samples are multiply Type I hybrid censored. The scale parameter is estimated by approximate maximum likelihood estimation methods using two different Taylor series expansion types ($\hat{\sigma}_I$, $\hat{\sigma}_{II}$). We compare the estimators in the sense of the root mean square error (RMSE). The simulation procedure is repeated 10,000 times for the sample size n=20 and 40 and various censored schemes. The approximate MLE of the second type is better than that of the first type in the sense of the RMSE. Further an illustrative example with the real data is presented.

• Journal of Chest Surgery
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• v.52 no.1
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• pp.32-35
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• 2019

Surgical management of interrupted aortic arch (IAA) with systemic outflow tract obstruction is clearly a challenge. If both ventricles are adequate, the Yasui operation is a useful option. Otherwise, a staged approach through initial hybrid palliation and delayed biventricular repair, tailored to the degree of obstructed outflow, serves to avoid a high-risk neonatal procedure. Herein, we present a patient with IAA and severe systemic outflow tract obstruction whose treatment involved hybrid palliation, followed by a Yasui operation.

• Journal of Chest Surgery
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• v.55 no.3
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• pp.239-242
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• 2022

Papillary muscle rupture with severe acute mitral regurgitation is a rare complication of acute myocardial infarction (AMI) that causes pulmonary congestion and cardiogenic shock. Moreover, it has a poor prognosis. Surgical intervention, including revascularization, is indicated; however, surgical mortality remains high. We report the case of an 85-year-old woman with cardiogenic shock from severe acute mitral regurgitation, in whom a hybrid intervention, combining percutaneous coronary intervention with mitral valve replacement via minithoracotomy, was performed after post-infarction papillary muscle rupture. She was discharged in a favorable clinical condition. We describe a novel hybrid intervention for treating a rare complication of AMI, which could minimize surgical invasion in elderly patients, prevent disuse syndrome after the intervention, and improve prognosis. However, mitral valve surgery via minithoracotomy for emergency cases requires technical proficiency, as well as collaboration with other healthcare professionals, and the choice to perform this procedure requires careful consideration.

• Journal of Korean Institute of Industrial Engineers
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• v.20 no.4
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• pp.113-134
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• 1994

A radial basis hybrid neural network (RHNN) is presented for an on-line detection of machine condition change. Two-phase modeling by RHNN is designed for describing a machine condition process and for predicting future signal. A moving block procedure is also designed for detecting a process change. A fast on-line learning algorithm, the recursive least square estimation, is introduced. Experimental results showed the RHNN could be utilized efficiently for on-line machine condition monitoring.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.197-202
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• 2000

A simple numerical procedure is presented to determine the stress intensity factors for crack in a stiffened panel subjected to a uniaxial uniform stress normal to the crack. Two types of stiffened panels are analyzed by the finite element method for various values of crack lengths, stiffness ratios, and stiffener spacings. From the finite element solution, the stress intensity factors were determined by using hybrid extrapolation method. Results are presented in graphical forms for upper mentioned parameters.

• Proceedings of the Korea Society for Simulation Conference
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• 2000.04a
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• pp.57-66
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• 2000

Production-distribution planning is the most important part in supply chain management (SCM). To solve this planning problem, either analytic or simulation approach has been developed. However these two approaches have their own demerits in problem solving. In this paper, we propose a hybrid approach which is a specific problem solving procedure combining analytic and simulation method to solve production-distribution problems in supply chain. The machine capacity and distribution capacity constraints in the analytic model are considered as stochastic factors and adjusted by the proposed specific process according to the results from independently developed simulation model which includes general production-distribution characteristics.

• Journal of the Korea Society for Simulation
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• v.1 no.1
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• pp.25-30
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• 1992

A knowledge based hybrid simulation environment has been established which supports the simulation procedure from the modeling step to the experimentation step by providing various tools, query, and advisory. The knowledge base in the established environment uses the If-Then Rule to transfer the fact input from the user to the act for the execution of the simulation process. Simulation non-experts are the user target and non-specific area is the application target.

• Steel and Composite Structures
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• v.13 no.1
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• pp.47-70
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• 2012

To enhance cable stiffness, this paper proposed a combined application of carbon fiber reinforced polymers (CFRP) and steel materials, resulting in a novel type of hybrid stay cable system especially for the cable-stayed bridges with main span lengths of 1400~2800 m. In this combination, CFRP materials can conserve all their advantages such as light weight and high strength; while steel materials help increase the equivalent stiffness to compensate for the low elastic modulus of CFRP materials. An increase of the equivalent stiffness of the hybrid stay cable system could be further obtained with a reasonable increase of its safety factor. Following this concept, a series of parametric studies for the hybrid stay cable system with the consideration of stiffness and cost were carried out. Three design strategies/criteria, namely, best equivalent stiffness with a given safety factor, highest ratio of equivalent stiffness to material cost with a given safety factor, and best equivalent stiffness under a given cost were proposed from the stiffness and cost viewpoints. Finally, a comprehensive design procedure following the proposed design strategies was suggested. It was shown that the proposed hybrid stay cable system could be a good alternative to the pure CFRP or traditional steel stay cables in the future applications of super long span bridges.

• Journal of Chest Surgery
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• v.43 no.5
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• pp.490-498
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• 2010

Background: A hybrid procedure using an open surgical extra-anatomic bypass of aortic arch vessels and thoracic endovascular aortic repair (TEVAR) is less invasive than open surgery, and provides a suitable proximal landing zone. Here we report our experience with a hybrid TEVAR procedure at a single center. Material and Method: We retrospectively reviewed consecutive patients with thoracic aortic disease who received a hybrid TEVAR procedure between August 2008 and January 2010. Patients' data were prospectively collected and mean follow-up was $10.8{\pm}5.5$ months (range 3~20). Result: Nine patients (7 males and 2 females) with a mean age of $63.8{\pm}15.8$ years (range 38~84) underwent a hybrid procedure. Five patients had an arch or a proximal descending aortic aneurysm, two had a dissecting aneurysm of the descending aorta, and two had an aneurysm of the ascending arch and descending aorta. Mean expected mortality calculated by logistic EuroSCORE was 21%. Six patients underwent debranching and rerouting from ascending aorta to arch vessels, 2 had carotid-carotid bypass grafting, and 1 underwent carotid-axillary bypass grafting. Mean operation time was $221.4{\pm}84.0$ min (range 94~364). Deployment success of endovascular stent grafting was 100% with no endoleak on completion angiography. There was no mortality, and a small embolism in the branch of the right opthalmic artery in one patient. During follow-up, one intervention was required for the endoleak. Actuarial survival at 20 months was 100%. Conclusion: Early and mid-term results are encouraging and suggest that hybrid TEVAR procedures are less invasive and safer and represent an effective technique for treating thoracic aortic disease.

• Journal of IKEEE
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• v.18 no.3
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• pp.313-319
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• 2014

The objectives of power system operations are to preserve system stability and reliability as well as to supply proper electric power. For an activation of these objectives, voltage and reactive power should be considered. There are a number of types about reactive power sources, and an insertion of shunt capacitor banks are one of the method to support bus voltage adjacent. This paper includes the design procedure to determine the hybrid type capacitor bank configurations on power system to improve stability and reliability. This procedure includes the capacitor bank capacity calculation, reactor type selection, and reactor capacity calculation. The total capacity calculation of capacitor bank is based on the reactive power margin which is calculated through system studies such as, contingency analysis and Q-V analysis. In the second step, the reactor type and its capacity can be determined through the harmonic analysis. This paper shows that the harmonics are decreased by the proposed hybrid type capacitor bank, especially 5th and 7th harmonics.