• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.04b
• /
• pp.314-319
• /
• 1995

The effect of liquid level on the natural frequencies and mode shapes of a partially liquid-filled circular cylindrical shell with various boundary conditions is investigated by means of a theoretical analysis based upon Fourier series expansion method and a finite element analysis using ANSYS computer program. Two dimensional mode shapes of the liquid-coupled shell structure are obtained by the ANSYS finite element analysis and show that the liquid level affect the nodal point movement. It is found that the variation of normalized naturalfrequencies (natural frequencies of liquid-filled shell/antural frequencies ofempty shell) to the liquid level is depend on the axial mode numbers and circumferential wave numbers. Additionally, it is found that the number of variational steps of normalized natural frequencies is identicial to that of axial nodal points of the mode shape.

• Wind and Structures
• /
• v.1 no.3
• /
• pp.243-253
• /
• 1998

The paper deals with numerical analysis of interference galloping of two elastically supported circular cylinders of equal diameters. The basis of the analysis is quasi-steady model of this phenomenon. The model assumes that both cylinders participate in process of interference galloping and they have two degrees of freedom. The movement of the cylinders is written as a set of four nonlinear differential equations. On the basis of numerical solutions of this equations the authors evaluate the correctness of this quasi-steady model. Then they estimate the dependence of a critical reduced velocity on the Scruton number, turbulence intensity and arrangements of the cylinders.

• Journal of the Korean Society of Visualization
• /
• v.19 no.3
• /
• pp.22-30
• /
• 2021

Ventilated cavity shapes by varying angle of attack of a circular cavitator were predicted based on Logvinovich's Independence Principle in order to verify the cavity shape prediction method. The prediction results were compared with model experiments conducted in the high-speed cavitation tunnel. In the prediction of the cavity centerline, the movement of the cavity centerline due to the effect of gravity and cavitator's angle of attack were well predicted. In the prediction of the cavity contour, it was found that the cavity edge prediction error increased as the angle of attack increased. The error of the upper cavity contour was small at the positive angle of attack, and the error of the lower cavity contour was small at the negative angle of attack.

• Smart Media Journal
• /
• v.13 no.4
• /
• pp.94-103
• /
• 2024

The eyeball input system is a text input system designed based on 'eye tracking technology' and 'virtual keyboard character-input technology'. The current virtual keyboard structure used is a rectangular QWERTY array optimized for a multi-input method that simultaneously utilizes all 10 fingers on both hands. However, since 'eye-tracking technology' is a single-input method that relies solely on eye movement, requiring only one focal point for input, problems arise when used in conjunction with a rectangular virtual keyboard structure designed for multi-input method. To solve this problem, first of all, previous studies on the shape, type, and movement of muscles connected to the eyeball were investigated. Through the investigation, it was identified that the principle of eye movement occurs in a circle rather than in a straight line. This study, therefore, proposes a new key arrangement wherein the keys are arranged in a circular structure suitable for rotational motion rather than the key arrangement of the current virtual keyboard which is arranged in a rectangular structure and optimized for both-hand input. In addition, compared to the existing rectangular key arrangement, a performance verification experiment was conducted on the circular key arrangement, and through the experiment, it was confirmed that the circular arrangement would be a good replacement for the rectangular arrangement for the virtual keyboard.

• Proceedings of the KSME Conference
• /
• 2000.04a
• /
• pp.786-791
• /
• 2000

The purpose of this study is to investigate quantitatively the effects of drawbead dimensions to the weld line movements for the deep drawing of the tailor welded blanks. Square blanks have been used and five different circular drawbeads were installed in experimental apparatus. The differences in the weld-line movements and the tendencies of the strain distributions in thickness were investigated by experimental and analytical methods. The results of the weldline movement show that the smaller the radius of drawbead installed, the larger the values of movements. Also it is shown for thickness strain in central and diagonal direction that the larger the dimension of drawbead, the larger the values of maximum thickness strain. The drawbead adds the additional restraining forces to the blank, hence the movement of weld line could be controlled by the adequate drawbead installation

• Wind and Structures
• /
• v.9 no.1
• /
• pp.75-93
• /
• 2006

This paper presents a quasi-steady model of vibrations of two cylinders in a side-by-side arrangement. The cylinders have flexible support and equal diameters. The model assumes that both cylinders participate in the process of vibration, each of them having two degrees of freedom. The movement of cylinders is described by a set of four non-linear differential equations. These equations are evaluated on the basis of a numerical simulation and experimental data. Moreover many features of cylinder vibrations are found from numerical results and are described in this paper.

• Journal of Sensor Science and Technology
• /
• v.10 no.1
• /
• pp.71-79
• /
• 2001

The use of a glass-plate probe of rectangular shape is proposed for the measurement of transmission loss in optical waveguides. The light-collecting window is of a thin, rectangular shape and is perpendicular to the light streak, while the conventional fiberglass probe has a small circular face. This transversely elongated form results in a grate improvement of mechanical tolerance for the probe movement in the vortical as well as in the transverse direction. A theoretical investigation also presents a reasonable agreement with the experiments.

• Tribology and Lubricants
• /
• v.4 no.2
• /
• pp.60-67
• /
• 1988

Conventional theory of gear mechanism can't be applied to analyze the harmonic drive due to specific movement of the teeth. This paper deals with an analysis of kinematics and geometry of the tooth engagement of a harmonic drive comprising circular spline, flexspline and wave generator. A theoretical new tooth profile of the flexspline in meshing internal rigid gear with involute profile is obtained. Characteristics of harmonic drive reducer are shown according to parameters such as deviation coefficient, deviation distance, addendum modification coefficient. As an example, the design of harmonic drive with 1:80 reduction ratio is presented.

• Korean journal of applied entomology
• /
• v.33 no.1
• /
• pp.33-38
• /
• 1994

The expenment was conducted to study the foraging behavior of Amblyseius hngisp~nosus for eggs of Tetranychus urticoe. When preys were abundant, A. longispinosus repeated a series of foraging process (feeding, after-feeding movement, restmy, and searching) The time (Mean\ulcorner SD) spent for these components were 6 83+ 1.73. 3 OOi 1.66. 93.57+ 30 19. and -0.00 min., respectively. Afterfeeding movement was chractetired as a complex one-way circular moving path with a slow speed (0.09 mm/sec) and area-restricted Escaping movement was fast (0 31 mm/sec), more straight in direction, and edge-oriented walking. Positions of prey consumption of A. longispinosus were distributed in clump. KEY WORDS Foraging behavior, nlovlng path, Arnblyseius longispinosus, Tetranychus urtlcae.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.1090-1097
• /
• 2008

This study conducted the decision method of lateral flow in abutment structures founded on the soft soils and the reliability analysis on the foundation pile for abutment. On the basis of the results, this study proposed the reliability design model. Reliability analysis was conducted by applying second moment method, point estimation method, and expected total cost minimization to lateral movement index, lateral movement decision index, modified lateral movement decision index, and circular failure safety factor for the decision criteria of lateral flow. The reliability index by analysis method had a similar tendency each other. Point estimation method was found as a practical method in the aspect of convenience because it could conduct the analysis only by mean and standard deviation as well as the partial derivative on random variables was not necessary. Optimum reliability index and optimum safety according to increasing in failure factors and load ratio were analyzed and loads and resistance factors of the design criteria of optimum reliability were estimated. It presented rational design model which can consider construction level and stability and economical efficiency overall.