• Journal of Institute of Control, Robotics and Systems
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• v.6 no.10
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• pp.881-887
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• 2000

There are significant nonlinearities and uncertainties in hard disk drive actuators. In particular, pivot bearing nonlinearity and repeatable run-out make track-following control difficult as track density increases. In this paper, we design a robust track-following controller using a robust deterministic control scheme in which the pivot bearing nonlinearity and repeatable run-out are considered as uncertainties. Simulation study is conducted to evaluate the control performance of the proposed control scheme.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.261-266
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• 2003

The present paper theoretically investigates characteristics of moment balance of a tilting-pad thrust bearing. Pressure of lubricant film of the bearing was computed using tile finite element method, and average film temperature was estimated from the heat balance over a pad. From the investigation, it has been found that different two sets of tilt angles satisfy moment equilibrium of the pad about tile pivot for a given pivot location. The tilt angles converged depend upon initial tilt angles assumed. Quite different bearing performance, including load capacity, film thickness, and temperature, is shown to be obtained based on choice of the initial tilt angles.

• Tribology and Lubricants
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• v.10 no.1
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• pp.35-45
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• 1994

The thermohydrodynamic analysis of tilting pad thrust bearing is studied with the consideration of elastic effect of pad. Reynolds equation, deflection equation and energy equation are solved simultaneously with the boundary conditions. Reynolds equation is modified as the approximate form. Pads are supported by the line pivot and the point pivot respectively. Pads are considered as the flat planes. Effects of pad thickness on the performance of thrust bearing are emphasized and the performances of rigid pad and elastic pad are compared. Effects of inlet temperature on performances of the bearing are compared. Dynamic characteristics of both pad supported by line and point pivot are compared.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.2
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• pp.58-63
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• 2008

This paper describes aerodynamic performance enhancement of cycloidal rotor according to the blade pivot point movement and the blade preset angle adjustment. Cycloidal blade system which consists of several blades rotating about an axis in parallel direction and changing its pitch angle periodically, is a propulsion mechanism of a new concept vertical take off and landing aircraft, cyclocopter. Based on the designed geometry of cyclocopter, numerical analysis was carried out by a general purpose commercial CFD program, STAR-CD. According to tills analysis, the efficiency of cycloidal rotor could be improved more than 15% by the introduced methods.

• The Research Journal of the Costume Culture
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• v.2 no.1
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• pp.29-38
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• 1994

This research has been to perform with various methods of measurement of human body. As experiment methods, performed the body measurement method with Martin's measurer, took pictures for he observation of body gesture and body shape, and applied the cross-section measurement method of each body part for the making of body pivot. In the making of body pivot. used several sheets of styroform, and attached some gypsum power on the surface of the body pivot for he body silhouette of body. Eventhough, there were not enough subjects for this study, these methods will be continuously conducted with enough subjects, there will be to develop the body measurement method for Korean women, and will find to solve a suitable manufacturing body and the study of body for Korean women.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.415-420
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• 2010

Due to the improvement in PC performance and the development of computer graphics technology, high quality computer animation in various industrials is on the rise. This study suggests pivot interpolation to realize the process of expressing dynamic and natural motion of fish, the key of expressing the ocean landscape through the morphing technique. By applying fish tail motion, this study solves unnatural speed of the previous morphing technique and realizes the realistic swimming way without simple motion.

• Tribology and Lubricants
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• v.20 no.3
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• pp.152-156
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• 2004

The present paper theoretically investigates characteristics of moment balance of a tilting-pad thrust bearing. Pressure of lubricant film of the bearing was computed using the finite element method, and average film temperature was estimated from the heat balance over a pad. From the investigation, it has been found that different two sets of tilt angles satisfy moment equilibrium of the pad about the pivot for a given pivot location. The tilt angles converged depend upon initial tilt angles assumed. Quite different bearing performance, including load capacity, film thickness, and temperature, is shown to be obtained based on choice of the initial tilt angles.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.170-176
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• 2008

The concept design of Flexible Seal for thrust vector control of solid motor was performed. Through the concept design, the optimum pivot point of flexible seal, cross-section configuration of flexible seal and thermal protection system from combustion gas was decided. The pivot point of flexible seal has aft pivot type and cross-section view is conical type. For satisfying a spring torque rate, the shear modulus of rubber has the value of under about 0.6MPa and failure shear stress has over about 2.5MPa.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.23 no.1
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• pp.224-252
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• 2010

Objective : The purpose of this study is to investigate tinnitus of Plain Questions $\ll$素問$\gg$ and Miraculous Pivot $\ll$靈樞$\gg$. Methods : We conducted a study on the original text paragraphs of Internal Classic $\ll$內經$\gg$ containing the tinnitus and analysis of Yang, Ma, Zhang, Wang etc. We drew a parallel between tinnitus from Internal Classic $\ll$內經$\gg$ and matching diagnoses from western medicine. Results : The results were as follows. 1. Tinnitus in Plain Questions $\ll$素問$\gg$Tong Pyeong Heo Sil Ron <通評虛實論> was similar to the symptoms of diabetes mellitus complication and schizophreniform disorder in western medicine. 2. Liver fire tinnitus in Plain Questions $\ll$素問$\gg$ Yuk Won Jeong Gi Dae Ron <六元正紀大論> was similar to the symptoms of psychological distress in western medicine. 3. Phlegm fire tinnitus in Plain Questions $\ll$素問$\gg$ Ji Jin Yo Dae Ron <至眞要大論> was similar to the symptoms of meniere's disease and malfunction of autonomic nervous system in western medicine. 4. Blood deficiency tinnitus in Miraculous Pivot $\ll$靈樞$\gg$ Sa Gi Jang Bu Byeong Hyeong <邪氣藏府病形> was similar to the symptoms of anemia in western medicine. 5. Tinnitus in Miraculous Pivot $\ll$靈樞$\gg$ Gyeong Geun <經筋> was similar to the myofacial pain syndrome of the sternocleidomastoid muscle and the masseter muscle in western medicine. 6. Gallbladder deficiency tinnitus in Miraculous Pivot $\ll$靈樞$\gg$ Gwol Hyeong <厥病> was similar to the symptoms of otitis media and labyrinthitis in western medicine. 7. Kidney deficiency tinnitus in Miraculous Pivot $\ll$靈樞$\gg$ Gyeol Gi <決氣> and Hai Ron <海論> was similar to the symptoms of degenerative auditory organ in western medicine. 8. Tinnitus in Internal Classic $\ll$內經$\gg$ showed close relations with the symptoms of the wind character. Conclusion : We analyzed the original text paragraphs of Internal Classic $\ll$內經$\gg$ and explanations about tinnitus. Further studies are needed to compare oriental medicine and western medicine diagnoses to develop better treatments for tinnitus.

• Journal of Aerospace System Engineering
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• v.18 no.1
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• pp.64-71
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• 2024

The external fuel tank of an aircraft is a main component that can increase the cruising range of the aircraft. It must be able to be stably separated from the pylon in an emergency situation. At this time, a separation load is applied to the fin and the pivot of the external fuel tank. To stably separate the external fuel tank, the structural soundness of the fin and the pivot must be confirmed. In this study, structural tests were conducted to verify the structural integrity of the external fuel tank pin and pivot when the external fuel tank was separated from the aircraft. Results are then presented. In this paper, a test configuration diagram consisting of the hydraulic and load control equipment, data acquisition system, and pneumatic supply unit used in the structural test was explained. Test installation and test load application plan for each test condition were provided. As results of the structural test, it was found that test load and internal pressure of the test specimen were properly controlled within the allowable range in each test. It was confirmed that serious structural defects in the test specimen did not occur under required load conditions. In conclusion, through structural test for design limit load and design ultimate load, it was proven that the fin and pivot of the external fuel tank for aircraft covered in this study had sufficient structural strength.