• Journal of the Korean Geosynthetics Society
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• v.14 no.1
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• pp.11-21
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• 2015

This study aims at investigating of the behavioral characteristics of foundation ground subjected to a strip load in anisotropy. Using marine clays sampled at Shihwa area, a series of laboratory tests including triaxial compressive test, plane strain compressive and expansion tests that allows horizontal deformation only and zero strain (${\varepsilon}_2$) in the direction of intermediate stress (${\sigma}_2$) are conducted. In addition, a numerical analysis using parameters obtained from the tests is carried out. In the numerical analysis, Cam-clay model that simulates the behavior of natural deposited clay properly is adopted. The analysis results show that the vertical displacements of the plane strain compressive tests are relatively larger than those of triaxial compressive tests by 18-25%. Likewise, the horizontal displacements is 13-19% larger.

• Journal of the Korean Geotechnical Society
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• v.33 no.11
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• pp.59-72
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• 2017

In this study, the calculation method of the active earth pressure acting on the imaginary vertical plane at the end of the heel of the wall is proposed. For cantilever retaining wall, a change of shear zone behind the wall affects the earth pressure in the vertical plane at the end of heel of the wall depending on wall friction and angle of ground slope. It is very complicated to calculate the earth pressure by a limit equilibrium method (LEM) which considers angles of failure planes varying according to the heel length of the wall. So, the limit analysis method (LAM) is used for calculation of earth pressure in this study. Using the LAM, the earth pressures considering the actual slope angles of failure plane are calculated accurately, and then horizontal and vertical earth pressures are obtained from them respectively. This study results show that by decreasing the relative length of the heel, the slope angle of inward failure plane becomes larger than theoretical slope angle but the slope angle of outward failure plane does not change. And also the friction angle on the vertical plane at the end of the heel of the wall is between the ground slope angle and the wall friction angle, thereafter the active earth pressure decreases. Finally, the Coulomb earth pressure can be easily calculated from the relationship between friction angle (the ratio of vertical earth pressure to horizontal earth pressure) and relative length of the heel (the ratio of heel length to wall height).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.806-812
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• 2009

In this paper, the omnidirectional circularly polarized(CP) antenna using arc-shaped mushroom structure with curved branch is proposed. To obtain a vertical polarization and an omnidirectional radiation pattern, the CP antenna uses zeroth-order resonance(ZOR) mode of composite right and left handed(CRLH) transmission line. The horizontal polarization is achieved by the curved branches. Also, the spacing between curved branch and arc-shaped mushroom structure gives the $90^{\circ}$ phase difference between vortical and horizontal polarization. The proposed antenna, therefore, has an omnidirectional CP radiation pattern In the azimuthal plane. The electrical size of the proposed antenna is reduced by 38%, compared with that of the previously presented omnidirectional CP antenna. In addition, the CP antenna is simply designed without $90^{\circ}$ phase shifter and dual feed line. The proposed antenna uses a Bazooka balun for good impedance matching and radiation pattern. To improve 3 dB axial ratio in XY plane, the designed antenna is optimized. After optimization, the measured 3 dB axial ratio in XY plane is observed in $86{\sim}282^{\circ}$.

• Steel and Composite Structures
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• v.31 no.6
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• pp.541-558
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• 2019

In Special Concentrically Braced Frames (SCBFs), vertical and horizontal components of the brace force must be resisted by column and beam, respectively but normal force component existing at the gusset plate-to-column and beam interfaces, creates out-of-plane action making distortion in column and beam faces adjacent to the gusset plate. It is a main concern in Hollow Structural Section (HSS) columns and beams where their webs and gusset plate are not in the same plane. In this paper, a new gusset plate passing through the HSS columns and beams, named as through gusset plate, is proposed to study the force transfer mechanism in such gusset plates of SCBFs compared to the case with conventional gusset plates. For this purpose, twelve SCBFs with diagonal brace and HSS columns and twelve SCBFs with chevron brace and HSS columns and beams are considered. For each frame, two cases are considered, one with through gusset plates and the other with conventional ones. Based on numerical results, using through gusset plates prevents distortion and out-of-plane deformation at HSS column and beam faces adjacent to the gusset plate helping the entire column and beam cross-sections to resist respectively vertical and horizontal components of the brace force. Moreover, its application increases energy dissipation, lateral stiffness and strength around 28%, 40% and 32%, respectively, improving connection behavior and raising the resistance of the normal force components at the gusset plate-to-HSS column and beam interfaces to approximately 4 and 3.5 times, respectively. Finally, using such through gusset plates leads to better structural performance particularly for HSS columns and beams with larger width-to-thickness ratio elements.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.551-558
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• 2005

In this paper, horizontal manoeuvrability of an underwater vehicle near free surface was investigated. Planar Motion Mechanism(PMM) tests were performed at the shallow depth within 4.5 times of vehicle's diameter. Hydrodynamic coefficients related to the horizontal movement were estimated from the measured data using Least SQuare(LS) method and analyzed at each submerged depth. Furthermore, horizontal dynamic stability, trajectory of turning and zigzag test were investigated for the various depths. As underwater vehicle is positioned nearer to the free surface, forces increase and moment decreases. Tested model was found to be stable only at the depth 0.5 times of vehicle's diameter.

• The korean journal of orthodontics
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• v.31 no.1 s.84
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• pp.97-105
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• 2001

In many cases of orthodontic treatment the upper anterior teeth are retracted. Periodontal problems may arise during incisor retraction, if the amount of tooth movement and the amount of remodeling in the anterior cortical bone are not the same. Therefore in this study, to find out the relationship between the amount of tooth movement and the amount of bone remodeling during retraction of the upper anterior teeth, lateral cephalograms of 56 female patients over 18-year-old were taken before and after treatment. Among the 56 patients, two groups were divided according to the type of root movement during retraction. 26 patients mainly moved by tipping and 30 by bodily movement. The cephalograms taken before and after treatment were superimposed upon the true horizontal plane. In the Tip-Group, the horizontal bone remodeling/tooth movement ratio was 1:1.63, and in the Torque-Group it was 1:1.66. Because the amount of tooth movement and the amount of bone remodeling were not the same in both groups, in the Tip-Group the root apex moved away from the palatal cortical plate and closer to the labial cortical plate, whereas in the Torque-Group the root moved away from the labial cortical plate and closet to the palatal cortical plate. Therefore, there are limitations in the amount of incisor retraction in patients with a very thin anterior cortical plate in the maxilla, and in patients with severe skeletal discrepancies orthognathic surgery should be considered and when orthodontic camouflage treatment is the only possible method, the orthodontist must be aware of the limitations of treatment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.8
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• pp.21-29
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• 2013

The functional behaviors of human standing postural control were investigated when they were exposed to long-term horizontal vibration in the sagittal plane. For complexity of human postural control, a useful alternative method that has been based on a black-box approach was taken; that is, where the feedback mechanism was lumped into a single element. A motor-driven support platform was designed as a source of vibration. The AC Servo-controlled motors produced continuous anterior/posterior (AP) motion. The data were analyzed both in the time and frequency domain. The cross-correlation and coherency functions were estimated. Subjects behaved as a non-rigid pendulum with a mass and a spring throughout the whole period of the platform motion, as consistent with the plan chosen for this study.

• Geomechanics and Engineering
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• v.5 no.4
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• pp.299-312
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• 2013

The horizontal pullout capacity of a group of two vertical strip plate anchors, placed along the same vertical plane, in a fully cohesive soil has been computed by using the lower bound finite element limit analysis. The effect of spacing between the plate anchors on the magnitude of total group failure load ($P_{uT}$) has been evaluated. An increase of soil cohesion with depth has also been incorporated in the analysis. For a weightless medium, the total pullout resistance of the group becomes maximum corresponding to a certain optimum spacing between the anchor plates which has been found to vary generally between 0.5B and B; where B is the width of the anchor plate. As compared to a single plate anchor, the increase in the pullout resistance for a group of two anchors becomes greater at a higher embedment ratio. The effect of soil unit weight has also been analyzed. It is noted that the interference effect on the pullout resistance increases further with an increase in the unit weight of soil mass.

• The Journal of Korean Physical Therapy
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• v.12 no.2
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• pp.95-105
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• 2000

Glenohumeral internal and external rotation with shoulder abducted in the frontal plane often causes impingement of the supraspinatus tendon. whereas similar activity in scapular plane does not cause impingement. The Purpose of this study was to determine if assessment among the three positions as 30 degrees, 60 degrees, 90 degrees abduction in the sitting position of the scapular plane could be affected the comparison between intemal and external peak torque, total work, average power. In this study, Isokinetic shoulder rotational strength was evaluated in twenty healthy male university students, using the Cybex NORMTM System (CYBEX Division of LUMEX, Inc., Ronkonkoma, New York). Test data was gathered in the plane of the scapular, 30 degrees of horizontal flexion anterior to coronal plane, and the subjects performed the test with the arm 30, 60, and 90degrees abducted in the sitting position. also, test speed was set at deg/sec. Statistical analysis was performed using SPSS 7.5 for Windows software and mean and standard deviations were calculated. ANOVA was used to analyze the difference of the values in the three test positions. A paired t-test was used of examining the difference in the means peak torque between external and internal rotation. Not any significant difference was found among three abduction positions in scapular plane, even though there was a consistent pattern of greater strength in the abducted position of 60 degrees. Internal relation strength peak torque and total work were greater than those of external rotation in every test positions.

• Journal of computational fluids engineering
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• v.4 no.2
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• pp.1-8
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• 1999

Natural convection in a horizontal annulus with the inner cylinder heated by the application of a constant heat flux and the isothermally cooled outer cylinder is considered, and the transition of flows and the bifurcation phenomenon are numerically investigated for air with Pr=0.7. The zero initial condition always induces a crescent-sheped eddy flow. A bicellular flow in which the fluid descends along the vertical central plane of the annulus can be obtained at high Rayleigh number by introducing artificial numerical disturbances. Dual solutions are found above a certain critical Rayleigh number. Hysteresis phenomena have not been observed.