• International journal of advanced smart convergence
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• v.7 no.2
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• pp.22-32
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• 2018

In VANET, frequent movement of nodes causes dynamic changes of the network topology. Therefore the routing protocol, which is stable to effectively respond the changes of the network topology, is required. Moreover, the existing cluster-based routing protocol, that is the hybrid approach, has routing delay due to the frequent re-electing of the cluster header. In addition, the routing table of CBRP has only one hop distant neighbor nodes. PCBRP (Paired CBRP), proposed in this paper, ties two clusters in one pair of clusters to make longer radius. Then the pair of the cluster headers manages and operates corresponding member nodes. In the current CBRP, when the cluster header leaves the cluster the delay, due to the re-electing a header, should be occurred. However, in PCBRP, another cluster header of the paired cluster takes the role instead of the left cluster header. This means that this method reduces the routing delay. Concurrently, PCBRP reduces the delay when routing nodes in the paired cluster internally. Therefore PCBRP shows improved total delay of the network and improved performance due to the reduced routing overhead.

• Journal of The Korean Digital Architecture Interior Association
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• v.7 no.2
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• pp.73-78
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• 2007

Proper methods for facilities distribution are suggested by the examination of researches on facilities distribution, the analysis of the scope that facilities are used, and the consideration of facilities demand, and proper distribution and placement of facilities suitable for each stage is suggested. The theoretical examination for proper distribution and the analysis of the use scope is made. As a result. the area covers four dongs(administrative unit) within 1km. The $80{\sim}90%$ of residents who use the existing facilities are the ones living within 1km and so the zone of life in everyday life depending on walking as a means of movement is found to be expanded by the developments in transportation means and road construction. Therefore I suggested that lifetime sports facilities be established within the use scope whose radius and area are 1km and 4km2, respectively, regarding the sports facilities as a community center which can playa role of an institution of community center.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.10a
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• pp.65-71
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• 1997

Computer simulations and test trials are carried out to get the optimal conditions about the stamping die design of the tailor laser welded automotive door inner. Firstly, the stamping process including gravity deflection, bead calibration, binder wrap, forming and spring back, are analyzed by the computer simulation. The results of simulation shows good correspondance with those of test trial under the same conditions. The variables of parametric study which will be investigated in the simulation and test trials, are determined form the results of the first run. The formability under the various conditions is evaluated, which are the initial postion of blank, blank holding force, corner radius and the shape of drawbead. Finally, well controled sound product without fracture, wrinkling and excessive weldline movement is obtained.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.10
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• pp.751-759
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• 2003

The theoretical method is developed to investigate the vibration characteristics of the sloshing and bulging mode for the circular cylindrical storage tank with an annular plate on free surface. The cylindrical tank is filled with an inviscid and incompressible liquid. The liquid domain is limited by a rigid cylindrical surface and a rigid flat bottom. As the effect of free surface waves Is taken into account in the analysis, the bulging and sloshing modes are studied. The solution for the velocity potential of liquid movement is assumed as a suitable harmonic function that satisfies Laplace equation and the relevant boundary conditions. The Rayleigh-Ritz method is used to derive the frequency equation of the cylindrical tank. The effect of Inner-to-outer radius ratio and thickness of annular plate and liquid volume on vibration characteristics of storage tank is studied. The finite element analysis is performed to demonstrate the validity of present theoretical method.

• Korean Journal of Applied Biomechanics
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• v.30 no.3
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• pp.205-215
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• 2020

Objective: The purpose of this study was to investigate the relative angles and cross-correlation between body segments and ski among four alpine ski turning techniques. Method: 19 alpine ski instructors participated in this study. Each skier asked to perform 4- types of turning technique, classified by radius and level. 8 inertial measurement units were used to measure orientation angle of segment and ski on the anteroposterior and vertical axis. Results: Significant differences were found between types of turning in the segments-ski relative angle on the anteroposterior and vertical axis (p<.05). Although, cross-correlation showed a high correlation between angles of segment and ski, there were significant differences between types of turning. Conclusion: Based on our results, the relative movement and timing between each segment and ski is different according to the turning techniques, so the training methods should be applied differently.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.6
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• pp.17-23
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• 2002

A new 3D micromachining method called Hole Area Modulation(HAM), has been introduced to enhance the current micromachining technology. In this method, information on the depth of machining is converted to the sizes of small holes in the mask. The machining is carried out with a simple 2D movement of the workpiece. This method can be applied for machining various kinds of microcavities in various materials. In this paper, a machematical model for excimer laser micromachining based on HAM and also determination of optimal laser ablation conditions(width hole radius, step size, path, etc.) is performed by Genetic Algorithm(GA).

• Journal of the Korean Society for Precision Engineering
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• v.28 no.8
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• pp.942-950
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• 2011

Automation is important in modern agricultural environment, which demands the highest level of technology. In the paper an independent four-wheel steering driving platform is developed especially for horticulture in glass house farm. Mathematical modeling of the four wheel system is carried out for smooth movement. The relationships between steering angle, the turning radius, and escape trajectory are simulated using the dynamic analysis program. Optimal driving algorithm is sought through the performance evaluation.

• Transactions of Materials Processing
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• v.7 no.4
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• pp.382-392
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• 1998

Computer simulations and test trials were carried out to obtain the optimal stamping conditions of the die design of the laser welded automotive body. The stamping process including gravity deflection bead calibration binder wrap, forming and spring back was simulated and compared with the results obtained from test trials. The production variables were determined from a preliminary operation and they were investigated in the simulation and the test trials. The formability was tested under the various conditions, such as the initial position of blank, blank holding force, corner radius and the shape of drawbead. Sound products without fracture, wrinkling and excessive weldline movement were produced by applying results obtained this investigation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.1076-1079
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• 1997

A new 3D micromachining method, called Hole Area Modulation(HAM), has been introduced and experimentally confirmed its feasibility. In this method, information on the depth of machining is converted to the sizes of small holes in the mask. The machining is carried out with a simple 2D movement of the workpiece. This method can be applied for machining various kinds of microcavities in various materials. In this paper, a mathematical model for excimer laser micromachining based on HAM and also determination of the optimal laser ablation conditions(width, Hole radius, step size, path, etc.) is completed by employing using Genetic Algorithm(GA).

• Journal of Astronomy and Space Sciences
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• v.5 no.2
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• pp.81-96
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• 1988

We have made new models for mass-losing OH/IR stars to explain the properties of the dust shells around them using more accurate information about the material in the shell and the physical precesses including pulsations. We have applied our dust opacity which has been deduced from observations and experimental data to various density distributions, calculated the model emergent spectra, and compared with observations. Contrary to previous suggestions, we could fit observations fairly well using density distribution $\rho\propto r^{-2}$, which is physically plausible, with proper choice of opacities. The time scales for dust formation, growth, and movement are calculated to be compared with pulsation periods. The change of the emergent spectrum depending on the phase of pulsation can be explained fairly well by changing dust condensation radius(for fixed dust condensation temperature) in step with the change in stellar luminosity. The effects of stellar wind models and pulsation models on dust shells with attention to emergent spectra are discussed.