• Journal of the Korean Society of Safety
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• v.15 no.2
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• pp.13-21
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• 2000

Under the mixed mode loading, it has been known that the influence of non-singular terms in the stress fields is serious, because the critical distance, ${\gamma}_o$ - the distance of nonlinear elastic region near the crack tip has no negligible value. In this paper, it has been studied on the influence of non-singular terms, T-stress, and the case of T=0, ${\sigma}cos^2{\beta}$, ${\sigma}cos(2{\beta})$ and $0.05{\sigma}cos(2{\beta})$, under uniaxial tension and compression. It has been seen that the T-stress of ${\sigma}cos(2{\beta})$ has better than others as comparing to the experimental data.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.82-88
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• 2002

A simple beam subjected to a uniformly distributed tangential follower force and the successive two moving spring-mass systems upon it constitute this vibration system. The influences of the velocities of the moving spring-mass system, the distance between the successive two moving spring-mass systems and the uniformly distributed tangential follower force have been studied on the dynamic behavior of a simple beam by numerical method. The uniformly distributed tangential follower force is considered within its critical value of a simple beam without the successive two moving spring-mass systems, and three kinds of constant velocities and constant distance of the successive two moving spring-mass systems are also chosen. Their coupling effects on the transverse vibration of the simple beam are inspected too.

• Transactions of Materials Processing
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• v.24 no.1
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• pp.28-36
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• 2015

After a short review of the iterative optimal blank method, a new method of measuring the shape error for stamped parts with 3D contour lines, which is an essential component of the optimal blank design, is proposed. When the contour line of the target shape does not exist in a plane, but exists in 3D space, especially when the shape of the target contour line is very complicated as in the real automotive parts, then the measurement of the shape error is critical. In the current study, a method of shape error measurement based on the minimum distance is suggested as an evolution of the radius vector method. With the proposed method, the optimal blank shapes of real automotive parts were found and compared to the results of the radius vector method. From the current investigation the new method is found to resolve the issues with the radius vector method.

• Journal of Welding and Joining
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• v.34 no.6
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• pp.20-27
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• 2016

This study deals with the proper conditions of the trail rolling method (TRM) for the prevention of the buckling welding distortion at the AA5083 GMA butt weldment. For it, the effect of the working conditions of TRM including the rolling depth and the rolling distance between the welding torch and the roller on the longitudinal welding shrinkage force of the weldment was evaluated by using 3 dimensional thermo-mechanical FE analyses. The longitudinal welding shrinkage force inducing the buckling welding distortion at the GMA butt weldment was mitigated with an increase in the rolling depth and the rolling distance between the welding torch and the roller. Based on the results, the proper conditions of trail rolling method were established to reduce the longitudinal welding shrinkage force of the GMA butt weldment to below the critical value corresponding to the bucking distortion.

• Journal of Navigation and Port Research
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• v.33 no.2
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• pp.105-110
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• 2009

Shipwaves am have harmful effects on ships working on the sea, in a harbour or navigational channel and caused beach erosion, seawall destruction. This study aims to investigate describe the characteristics of the wave pattern generated by an individual model ship tested at different velocities and hull forms for a given water depth and to investigate the variations at a given distance from the sailing line under the same conditions. As a result, the angles a's by model ship tests are smaller than those by real ship ones. Wave heights decreases with an increasing the mid-ship cross sectional area $A_s$. The maximum wave height and period increase rapidly in the subcritical speed, and beyond the critical speed the height and period decrease with increasing depth Froude number. And the period keeps constant with the distance from the sailing line.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.469-477
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• 2008

The standard routing protocol of MANET(Mobile Ad-hoc NETwork), AODV(Ad-hoc On-demand Distance Vector), only considers the shortest path for routing, which may cause traffic concentration to a node at the critical path. Hence, the battery of the node will be dissipated rapidly to reduce the lifetime of the whole network. In this paper, power dissipation considered AODV is proposed for fair energy distribution in MANET, and verified using the computer simulation.

• Journal of the Korean Society of Visualization
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• v.18 no.3
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• pp.52-60
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• 2020

When a bubble reaches a free surface, a bursting of the bubble produces a high speed jet. Despite its practical importance, significant effort has been devoted to investigate a bursting jet by a single bubble near a free surface. In the present study, we perform numerical simulations of bubbles in a tandem arrangement at Bo=0.05. The configuration of the tandem bubbles is systematically varied by changing a radius of a following bubble (RF) and the gap distance between two bubbles (L). Compared to a single bubble case, we show that the bursting bubble in the tandem arrangement accelerates, and the jet velocity increases. Moreover, we find that a critical gap distance at which the jet velocity unexpectedly changes exists in the tandem case.

• Geomechanics and Engineering
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• v.33 no.1
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• pp.53-63
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• 2023

Rock disturbance caused by blasting and stress relaxation is commonly observed during excavation. As the distance from the source of disturbance increases, the degree of disturbance decreases, and rock at a large depth does not experience disturbance. However, in stability analyses, a single value of disturbance is often applied to the entire rock mass, which leads to underestimated results. In this study, this modeling mistake is addressed by considering realistically varying rock disturbance. The safety of infinite slopes in a disturbed rock mass with a strength governed by the Hoek-Brown failure criterion is investigated based on the kinematic approach of limit analysis. The maximum disturbance is assigned to the outermost slope face because it is directly exposed to blasting damage and dilation, and the disturbance progressively decays with distance in the rock mass. The safety analysis results indicate that the assumption of uniform disturbance in the entire rock mass leads to underestimation of the rock strength and safety on infinite rock slopes. A critical slip surface appears to be within the disturbed rock layer as well as the interface between the disturbed upper rock and undisturbed lower rock.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.1014-1034
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• 2015

Location information of sensor nodes plays a critical role in many wireless sensor network (WSN) applications and protocols. Although many localization algorithms have been proposed in recent years, they usually target at dense networks and perform poorly in sparse networks. In this paper, we propose two component-based localization algorithms that can localize many more nodes in sparse networks than the state-of-the-art solution. We first develop the Basic Common nodes-based Localization Algorithm, namely BCLA, which uses both common nodes and measured distances between adjacent components to merge components. BCLA outperforms CALL, the state-of-the-art component-based localization algorithm that uses only distance measurements to merge components. In order to further improve the performance of BCLA, we further exploit the angular information among nodes to merge components, and propose the Component-based Localization with Angle and Distance information algorithm, namely CLAD. We prove the merging conditions for BCLA and CLAD, and evaluate their performance through extensive simulations. Simulations results show that, CLAD can locate more than 90 percent of nodes in a sparse network with average node degree 7.5, while CALL can locate only 78 percent of nodes in the same scenario.

• Progress in Medical Physics
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• v.5 no.1
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• pp.67-74
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• 1994

Dose distribution of point source represents an inverse square law as the distance, Difference of measurement value and calculation value according to moving distance of radiation source show very large error in dose calculation of Brachytherapy. Therefore, in RALS of high dose rate, dose calculation have an important effect in treatment of uterine cervix cancer and recurrent rate. In this paper, authors measured moving distance of radiation source carrying out RALS. And we measured Rectum dose compared with calculationdose.