• Journal of the Korean Mathematical Society
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• v.44 no.6
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• pp.1313-1327
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• 2007

We review the algebraic structure of $\mathbb{H}{\sharp}$ and show that $\mathbb{H}{\sharp}$ has a scalar product that allows as to identify it with semi Euclidean ${\mathbb{E}}^4_2$. We show that a pair q and p of unit split quaternions in $\mathbb{H}{\sharp}$ determines a rotation $R_{qp}:\mathbb{H}{\sharp}{\rightarrow}\mathbb{H}{\sharp}$. Moreover, we prove that $R_{qp}$ is a product of rotations in a pair of orthogonal planes in ${\mathbb{E}}^4_2$. To do that we call upon one tool from the theory of second ordinary differential equations.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.180-185
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• 2003

Performance test of servo control system that is used ultra-precision positioning system with single plane X-Y stage is performed by simulation with Matlab. Analyzed for previous control algorithm and adapted for modem control theory, dual servo algorithm is developed by minimum order observer, and stability priority on controller are secured. Through the simulation and experiments on ultra precision positioning, stability and priority on ultra-precision positioning system with single plane X-Y stage and control algorithm are secured by using Matlab with Simulink and ControlDesk made in dSPACE

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.610-615
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• 2003

This experiment has been carried out to find the structure of turbulent boundary layer with instantaneous velocity fields obtained in stream-wall-normal planes using a stereo-PIV (Particle Image Velocimetry) method. And it has been measured perpendicular plane and horizontal plane with hairpin vortex structure by Reynolds number change and made third dimension shape for section of horizontal plane through stereo-PIV. In the outer layer hairpin vortices occur in streamwise-aligned packets that propagate with small velocity dispersion. A streaky structure is composed of counter-rotating vortex. According as y+ increases, streaky structure's interval space decrease, and it shows that hairpin shape of prior research is vertified. The objective of the present research is to gain a better understanding of coherent structures in the outer of wall turbulence by experimentally examining coherent structures.

• Structural Engineering and Mechanics
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• v.58 no.4
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• pp.613-625
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• 2016

Contact interaction of a beam (flexible element) with an elastic half-plane is considered, when a soft inhomogeneous (functionally graded) interlayer is present between them. The beam is bent under the action of a distributed load applied to the surface and a reaction of the elastic interlayer and the half-space. Solution of the contact problem is obtained for different values of thickness and parameters of inhomogeneity of the layer. The interlayer is assumed to be significantly softer than the underlying half-plane; case of 100 times difference in Young's moduli is considered as an example. The influence of the interlayer thickness and gradient of elastic properties on the distribution of the contact stresses under the beam is studied.

• Journal of Aerospace System Engineering
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• v.15 no.4
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• pp.75-84
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• 2021

A novel robot-operating-system-based flight and mission state communication node for X-Plane 11 flight control simulation environments and its simulation results were discussed. Although the proposed communication method requires considerable implementation steps compared with the conventional MATLAB/Simulink-based User Datagram Protocol (UDP) block utilization method, the proposed method enables a direct comparison of cockpit-view images captured during flight with the flight data. This comparison is useful for data acquisition under virtual environments and for the development of flight control systems. The fixed/rotary-wing and ground terrain elements simulated in virtual environments exhibited excellent visualization outputs, which can overcome time and space constraints on flight experiments and validation of missionary algorithms with complex logic.

• Journal of Chest Surgery
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• v.55 no.6
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• pp.485-488
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• 2022

Serratus anterior plane block (SAPB) has been used for perioperative pain control during video-assisted thoracoscopic surgery (VATS), and the effects of continuous SAPB have been studied. This procedure is usually performed by the anesthesiologist; however, it could be performed more simply and safely by the thoracic surgeon through the use of meticulous finger dissection to create a space in the deep serratus anterior plane during surgery. We describe 3 cases of surgical catheterization for continuous SAPB in patients with lung cancer during VATS lobectomy, in which postoperative pain was effectively reduced.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.49.1-49.1
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• 2019

I present the mean metallicity distribution of stars in the Milky Way based on photometry from the Sloan Digital Sky Survey. I utilize an empirically calibrated set of stellar isochrones developed in previous work to estimate the metallicities of individual stars to a precision of 0.2 dex for reasonably bright stars across the survey area. I also obtain more precise metallicity estimates using priors from the Gaia parallaxes for relatively nearby stars. Close to the Galactic mid-plane (|Z| < 2 kpc), a mean metallicity map reveals deviations from the mirror symmetry between the northern and southern hemispheres, displaying wave-like oscillations. The observed metallicity asymmetry structure is almost parallel to the Galactic mid-plane, and coincides with the previously known asymmetry in the stellar number density distribution. This result reinforces the previous notion of the plane-parallel vertical waves propagating through the disk, which have been excited by a massive halo substructure such as the Sagittarius dwarf galaxy plunging through the Milky Way's disk. This work provides evidence that the Gaia phase-space spiral may continue out to |Z| ~ 1.5 kpc.

• East Asian mathematical journal
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• v.39 no.4
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• pp.479-492
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• 2023

Although Euclidean plane geometry is implemented in the middle school course, there are three major problems in high school space geometry that can be intuitively taken for granted or misinterpreted as circular arguments. In order to solve this problem, this study proved three major problems using sets, Euclidean plane geometry, and parallel line postulates. This corresponds to a logical sequence and has mathematical and mathematical educational values. Furthermore, it will be possible to configure spatial geometry using sets, and by giving legitimacy to non-Euclidean spatial geometry, it will open the possibility of future research.

• Korean Institute of Interior Design Journal
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• v.17 no.6
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• pp.128-136
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• 2008

It wouldn't be exaggerating to say that we're living in a "Brand age" these days. Brand is easily spotted anywhere around our surroundings, influencing us in a material and a moral way. BI(Brand Identity) which brings increase on sales by constructing and improving the brand image, are infect visually compressed Identity designs that will give the interior space that have applied it, superiority in building a unified image. Then, graphic plays an important role in expressing Identity designs visually. These days, interior space graphic is an emotional field that can materialize images, which became an important expressing medium that offers various images and creativity and show interior space's brand identity. In this manner, space graphic that applies identity designs, clearly states brand's intentions on space communication and users by designing company images or brand's emotional factors visually and dimensionally. Also, it escapes plane level, and gives space, dimensional and kinetic elements, which can give differentiation with other brand's space. These kinds of flexibility let space graphic be used efficiently in extending space identity.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.1
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• pp.100-108
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• 2008

This paper proposes a method of adaptively generating a gait pattern of biped robot. The gait synthesis is based on human's gait pattern analysis. The proposed method can easily be applied to generate the natural and stable gait pattern of any biped robot. To analyze the human's gait pattern, sequential images of the human's gait on the sagittal plane are acquired from which the gait control values are extracted. The gait pattern of biped robot on the sagittal plane is adaptively generated by a genetic algorithm using the human's gait control values. However, galt trajectories of the biped robot on the sagittal Plane are not enough to construct the complete gait pattern because the bided robot moves on 3-dimension space. Therefore, the gait pattern on the frontal plane, generated from Zero Moment Point (ZMP), is added to the gait one acquired on the sagittal plane. Consequently, the natural and stable walking pattern for the biped robot is obtained.