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Post Flight Analysis Using Numerical Weather Prediction Data, KLAPS
정석영,이재은,김민규,박성현 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.2
Numerical weather prediction data, in this study, were proposed to replace the meteorological measurement data acquired by widely used radiosonde, for the purpose of constructing atmospheric environment model applying to post flight analysis, especially evaluating aerodynamic performance in flight. KLAPS (Korea Local Analysis and Prediction System), the numerical weather model used in this study, is provided by the Korea Meteorological Administration every hour through the Internet and contains the meteorological information for a local region around the Korean peninsula, which is expected to give some advantage in the acquisition of regional and temporal variation of atmosphere state over the radiosonde measurement which has some drawbacks of acquiring data on only one point at one height while drifting via wind and taking some hours to climb up to 30 km high. The accuracy of KLAPS was verified by regenerating vertical distributions of atmospheric properties at the same locations and times as radiosonde measured and comparing them. Post flight analysis was carried out with an atmosphere environment model based on KLAPS and proved that the numerical weather model can provide an accurate atmospheric environment model enough to substitute the radiosonde measurement data.
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Multiple Arc Composition Technique for S-Duct Intake Construction Strictly Obeying Area Rule
정석영,이영환 한국항공우주학회 2023 International Journal of Aeronautical and Space Sc Vol.24 No.3
A technique was developed to design the intake duct shape by composing multiple arcs to build duct cross-sections, which presents the capability to represent the complex shape of various S-duct intakes by automatically generating intermediate cross-sections between given control cross-sections and flexibility to adjust those cross-sections to strictly obey prescribed area rule. Every cross-section is assumed to have a bilateral symmetric shape. The one half is divided into two pieces, top and bottom, each of which this multi-arc composition technique is applied to build. To overcome the underdetermined system even with the three-arc composition scheme, geometrical parameters are grouped into two sets. One is a set of parameters determined by geometry equations and imposed constraints. The other is a set of parameters obtained by morphing the features of intake cross-sections to fill the gap between the numbers of variables and equations. The concave shape of the intake cross-section can be handled by allowing some geometrical parameters, such as arc radius and angle, to have negative values. Some rules for morphing algorithm and a driving curve in addition to area variation have to be prescribed in advance and they are chosen to change linearly in this study. Demonstrations showed the ability of the three-arc composition technique by successfully generating various S-duct intakes consisting of complex shape cross-sections and strictly obeying a prescribed area rule.
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정석영 한국항공우주학회 2021 International Journal of Aeronautical and Space Sc Vol.22 No.4
A previously developed estimation technique, of the minimum energy required for complete fin deployment under an operational requirement of gust speed, was modified to consider time consumed for fin unfolding as an additional requirement, which might lead to an increase of the required energy. Some modifications were made such as non-zero kinetic energy of unfolding fin when completely deployed and its monotonically increasing angular speed during unfolding motion having a profile of square-root function which helped to properly evaluate elapsed time for fin unfolding and to combine the additional time constraint with the fin folding motion equation including external moments of aerodynamics, gravitation, and friction, while, in the previous study, zero energy and bell-shaped speed profile had been used. Demonstrations of this estimation technique considering the time constraint additionally to the gust speed requirement were carried out with the same unfolding fin system and torque profiles used in the previous study and showed that unfolding systems equipped with energy estimated by this technique met all the given gust requirement and time constraint, irrespective of their torque profile, in terms of elapsed time for fin unfolding and allowable wind speed denoting the maximum speed of gust against which in every direction fin could deploy.
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정석영,장찬웅,강성웅,김명상,최원아,조한얼 대한노인재활의학회 2023 Geriatric rehabilitation Vol.13 No.1
In this case report, we introduce on two unusual cases in which Non-invasive ventilation (NIV) was applied to elderly patients with respiratory failures. The first case needed ventilatory support because of acute respiratory failure. Although patient's situation was not “end-of-life”, but “curative”, surrogates did not agree to intubate since the patient had previously declared “do not intubate (DNI)”. The use of NIV allowed the patient to overcome the disease. The latter case, we introduce a patient with underlying tuberculosis-destroyed lung who showed dyspnea and chronic hypercapnia respiratory failure after influenza infection. This patient could manage hypercapnia and dyspnea through using NIV, and finally, she could wean the ventilator. Like our cases, if NIV can be used properly, treatment choices can be significantly expanded for patients with acute respiratory failure. We expected that these cases would widen the range of NIV use in elderly patients
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정석영,윤성준,변우식,안창수,Jung Suk Young,Yoon Sung Joon,Byon Woosik,Ahn Chang Soo 한국군사과학기술학회 2004 한국군사과학기술학회지 Vol.7 No.3
Numerical analysis of aerodynamic heating for KPSAM is performed using aerodynamic heating model suitable to KPSAM, which has complex flow field resulting from the spike attached to the dome, such as large separation area and the strong shock/boundary layer interaction region around reattachment point on the dome. The aerodynamic heating model is validated and modified through the comparison between the flight test measurement and the thermal analysis results. TFD temperature sensors are installed on the dome to measure surface temperature during the flight. Computation results, obtained from the heat transfer analysis on the sensors, agree well with flight test data. The aerodynamic heating model provides heat transfer rate into surface as a boundary condition of unsteady 1D/axisymmetric thermal analysis on the missile structure. The axisymmetric thermal analysis using FLUENT is more versatile than the 1D analysis and can be applied to the heating problem related with complex structures and multi-dimensional heat transfer problems such as prediction of temperature rise at contact surface of different materials.
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정석영,김두,안소저,박선일 한국임상수의학회 2006 한국임상수의학회지 Vol.23 No.3
This study was performed to monitor the level of serum canine parvovirus (CPV) antibody titers in adultdogs throughout the Korea from January 2003 to April 2004. A total of clinically healthy 885 dogs between 1 yearhemagglutination inhibition (HI) titers at the time dogs were brought to the hospital for revaccination. Most of dogshad been primarily vaccinated or previously revaccinated. Dogs were grouped by age, breed, sex, and primaryvaccination and revaccination to determine whether these factors were associated with antibody titers. Serum CPVtiters . 80 were considered protective. Protective antibodies against CPV were present in 95.0% of the population.Breed, age, and primary vaccination and revaccination were not significantly associated with serum CPV antibodytiters. But sex was significantly associated with CPV antibody titers. The results of this study have shown that thereis a need to reconsider the annual revaccination strategy against CPV infection.
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