• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.27.5-28
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• 2010

The unexpected observation condition or insufficient measurement modeling can lead to uncertain measurement errors. The uncertain measurement error of orbit determination problem typically consists of noise, bias and drift. It must be removed by using a proper estimation process for better orbit accuracy. The estimation of noise and drift is not easy because of their random or unpredictable variation. On the other hand, bias is a constant difference between the mean of the measured values and the true value, so it can be simply removed. In this study, precision orbit determination with SLR observations considering range bias estimation is presented. The Yonsei Laser-ranging Precision Orbit Determination System (YLPODS) and SLR NP (Normal Point) observations of CHAMP satellite are used for this work. The SLR residual test is performed to estimate the range bias of each arc. The result shows that we can get better orbit accuracy through range bias estimation.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.1
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• pp.26-34
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• 2016

Military devices and systems powered by batteries need to operate at extreme temperature and estimate the available capacity of the battery at different temperature conditions. However, accurate estimation of battery capacity is challenging due to the temperature-sensitive nature of electrochemical energy storage. In this paper, Peukert's equation with temperature factor is derived, and methods for estimating the absolute capacity of lithium-polymer battery and the state-of-charge(SOC) with respect to varying currents and temperatures are presented. The proposed estimation method is experimentally verified under three different discharge currents(0.5 A, 1 A, 3 A) and six different temperatures ranging from -30 to 45 deg. C. The results show the proposed method reduces the Peukert's estimation error by up to 30 % under or at extreme condition.

• Journal of Chest Surgery
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• v.2 no.2
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• pp.141-146
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• 1969

The importance of bronchial occlusion which occurs in the natural course of tuberculosis as an inconstant but very fortunate event became obscured with the popularity of resection therapy for pulmonary tuberculosis and the resectional surgery and thoracoplasty are the standard method of surgical procedure in the treatment of pulmonary tuberculosis. However in some cases of far advanced pulmonary tuberculosis, the need for another surgical methods arise when standard method is not indicated under the consideration of poor pulmonary function or operative and postoperative complications such as bronchial fistula. The ligation and division of bronchus draining the involved part of the lung is one of the applicable method among the another surgical procedures. The authors experienced one case of far advanced pulmonary tuberculosis who had a huge cavity in the right upper lobe and a small cavity in the superior segment accomanying with several nodular densities in the basal segment and contralateral left lung field, and treated with right upper lobectomy, ligation and division of the superior segmental bronchus and concomitant rib-resectional thoracoplasty in order to prevent postoperative bronchial fistula and to preserve maximal lung function. The postoperative course was smooth without complication regarding to bronchial ligation and division technique and the general condition has been excellent without symptoms. The postoperative sputum examination for AFB on smear and culture has been negative during the 11 month period of follow up, and X-ray of the chest including tomography demonstrated no evidence of residual cavity indicating succesful collapse of cavity.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.823-826
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• 1999

A 6-month old girl who had pulmonary atresia with ventricular septal defect and major aortopulmonary collaterals underwent one-stage complete repair with unifocalization through a bilateral thoracosternotomy(clamshell incision). There were no serious postoperative compli cations, and the postoperative echocardio-graphy showed no residual ventricular septal defect or significant pulmonary artery stenosis. In this condition, great surgical variability exists regarding the sources of pulmonary blood flow. Recent clinical work has focused on a one-stage complete repair. The potential advantages of the clamshell incision are apparent in terms of mediastinal approach, postoperative results, and safety.

• Journal of Korean Neurosurgical Society
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• v.41 no.6
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• pp.414-417
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• 2007

A 52-year-old woman with hypertension and moyamoya disease presented with chronic subdural hematoma [CSDH]. The presumed cause of bleeding was ascribed to administrated antiplatelet agents. She responded slowy and clumsily to verbal commands and had right arm weakness. After surgery, her clinical condition improved. But two days after surgery, her symptoms became aggravated and a convulsive seizure was noted within 24 hours. Brain magnetic resonance imaging showed no organic lesion except a small amount of residual CSDH. In addition, there was no laboratory evidence of metabolic brain disease. Moreover, after the administration of an antiepileptic drug [phenytoin], her manifestations disappeared. Therefore, the authors presume that her symptoms were resulted from nonconvulsive status epilepticus [NCSE], despite a lack of ictal period electroencephalographic findings. The authors were unable to find a single case report on postoperative NCSE in Korea. Therefore, the authors report this case of nonconvulsive status epilepticus after drainage of a CSDH in a patient with moyamoya disease.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.3
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• pp.87-99
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• 1994

Reynolds Averaged Navier-Stokes equations are solved numerically for the computation of turbulent flow around a Wigley double model. A second order finite difference method is applied for the spatial discretization on the nonstaggered grid system and 4-stage Runge-Kutta scheme for the numerical integration in time. In order to increase the time step, residual averaging scheme of Jameson is adopted. Pressure field is obtained by solving the pressure-Poisson equation with the appropriate Neumann boundary condition. For the turbulence closure, 0-equation turbulence model of Baldwin-Lomax is used. Numerical computation is carried out for the Reynolds number of 4.5 million. Comparisons of the computed results with the available experimental data show good agreements for the velocity and pressure distributions.

• Nuclear Engineering and Technology
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• v.49 no.5
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• pp.1006-1009
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• 2017

We discuss the problems of scattering in this framework, and show that the applied method is very useful in the investigation of the effect of the resonance in the observed scattering cross sections. In this study, not only the scattering cross sections but also the decomposition of the scattering cross sections was computed for the ${\alpha}-{\alpha}$ system. To obtain the decomposition of scattering cross sections into resonance and residual continuum terms, the complex scaled orthogonality condition model and the extended completeness relation are used. Applying the present method to the ${\alpha}-{\alpha}$ and ${\alpha}-n$ systems, we obtained good reproduction of the observed phase shifts and cross sections. The decomposition into resonance and continuum terms makes clear that resonance contributions are dominant but continuum terms and their interference are not negligible. To understand the behavior of observed phase shifts and the shape of the cross sections, both resonance and continuum terms are calculated.

• Journal of the Korean Society for Heat Treatment
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• v.32 no.2
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• pp.68-73
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• 2019

${\alpha}$-titanium alloy has a relatively low heat treatment characteristic and it is mainly subjected to heat treatment for residual stress, recovery or dynamic recrystallization. In this study, commercially pure titanium hollow castings was fabricated by gravity casting. Heat treatments were carried out at $750^{\circ}C$, $850^{\circ}C$ and $950^{\circ}C$ to investigate the effect of post-heat treatment on microstructure and mechanical properties. Beta-transus temperature ($T_{\beta}$) was about $913^{\circ}C$, and equiaxed microstructure was shown at temperature below $T_{\beta}$ and lath-type microstructure at temperature above $T_{\beta}$. Microstructure and mechanical properties did not show any significant difference in the direction of solidification for titanium hollow billet, so it can be seen that it was a well-made material for extrusion process. The optimum heat treatment condition of hollow billet castings for the seamless tube production was $850^{\circ}C$, 4 hr, FC, indicating a combination of equiaxed microstructure and appropriate mechanical properties.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.2_2
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• pp.239-245
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• 2022

Using the fatigue limit (∆σ_unsm) and residual stress (σ_r) of the UNSM smooth specimen, the harmless maximum crack depth (a_hlm) according to the crack aspect ratio (As) was evaluated. In addition, the relationship between the minimum crack depth (a_NDI1, a_NDI2) detectable by non-destructive inspection(NDI), the crack depth (a₂₅, a₅₀) that reduces the fatigue limit by 25% and 50%, and a_hlm were evaluated. The harmless crack condition was determined by the deepest crack point (point A). Since a_hlm is larger than a₂₅ and a₅₀, a₂₅ and a₅₀ can secure the safety and reliability of steel via UNSM. Because a_NDI1 and a_NDI2 are larger than a₂₅ and a₅₀, cracks in a₂₅ and a₅₀ cannot be detected by non-destructive testing. Therefore it is necessary to apply more precise NDI.

• Journal of Chest Surgery
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• v.54 no.6
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• pp.439-448
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• 2021

Remodeling is a commonly encountered term in the field of cardiothoracic surgery that is often used to describe various pathophysiological changes in the dimension, structure, and function of various cardiac chambers, including the aorta. Stanford type A or DeBakey type 1 aortic dissection (TAAD) is a perplexing pathologic condition that can present surgical teams with the need to navigate a maze of complex decision-making. Ascending or hemi-arch replacement leaves behind a significant amount of distal diseased aortic tissue, which might have a persistent false lumen or primary or secondary intimal tears (or communications between lumina), which can lead to dilatation of the aortic arch. Unfavorable aortic remodeling is a major cause of distal aortic deterioration after the index surgery. Cardiac surgeons are aware of post-surgical cardiac chamber remodeling, but the concept of distal aortic remodeling is still idealized. The contemporary literature from established aortic centers supports aggressive management of the residual aortic pathology during the index surgery, and with continuing technical advancements, endovascular stenting options are readily available for patients with TAAD or for complicated type B aortic dissection cases. This review discusses the pathophysiology and treatment options for favorable distal aortic remodeling, as well as its impact on mid- to long-term outcomes following TAAD repair.