• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.815-818
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• 2007

As wireless communications and mobile multimedia services are booming nowadays, systematic research of the overall aspects of mobile security is crucial. This paper presents a frame model for guising the systematic investigation of mobile security. Based on the introduction of some background viewpoints of security targets from n novel perspective, the kamework is described as a hierarchical model in which mobile security research is partitioned into three different layers.

• Journal of Environmental Health Sciences
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• v.17 no.1
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• pp.50-56
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• 1991

The purpose of this study was development of a simple phytoplankton model for reservoir and applied DaeCheung reservoir. The effects of light intensity, PO$_{4}$-P, settling rate and flushing loss on phytoplankton growth are analyzed. This paper describes as investigation of the potential of simple phytoplankton models to d/splay chaotic instability, but given the observation of chaotic behavior in other simple simulation systems, such behavoir may actually be real fluctuation in the system response.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.215-220
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• 2008

A numerical method for gas-liquid two-phase flow is applied to solve shock-bubble interaction problems. The present method employs a finite-difference Runge-Kutta method and Roe's flux difference splitting approximation with the MUSCL-TVD scheme. A homogeneous equilibrium cavitation model is used. By this method, a Riemann problem for shock tube was computed for validation. Then, shock-bubble interaction problems between cylindrical bubbles located in the liquid and incident liquid shock wave are computed.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.215-220
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• 2008

A numerical method for gas-liquid two-phase flow is applied to solve shock-bubble interaction problems. The present method employs a finite-difference Runge-Kutta method and Roe's flux difference splitting approximation with the MUSCL-TVD scheme. A homogeneous equilibrium cavitation model is used. By this method, a Riemann problem for shock tube was computed for validation. Then, shock-bubble interaction problems between cylindrical bubbles located in the liquid and incident liquid shock wave are computed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.161-166
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• 2001

The static characteristics of four-nozzle flapper valves are investigated with both constant flow and constant supply pressure. The ranges, in which linearization of these characteristics would be valid, are discussed. Linearized dynamic model is also derived. Numerical simulations of nonlinear dynamic model are carried out by HyPneu to make an assessment of the effect of input step size in both cases of no-load and blocked-load operation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.737-740
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• 2007

A s wireless communications and mobile multimedia services are booming nowadays, systematic research of the overall aspects of mobile security is crucial. This paper presents a frame model for guising the systematic investigation of mobile security. Based on the introduction of some background viewpoints of security targets from n novel perspective, the framework is described as a hierarchical model in which mobile security research is partitioned into three different layers.

• Fibers and Polymers
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• v.7 no.3
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• pp.310-316
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• 2006

In this article, an attempt has been made to explain the failure mechanism of spun yams. The mechanism includes the aspects of generation and distribution of forces on a fibre under the tensile loading of a yam, the free body diagram of forces, the conditions for gripping and slipping of a fibre, and the initiation, propagation, and ultimate yam rupture in its weakest link. A simple mathematical model for the tenacity of spun yams has been proposed. The model is based on the translation of fibre bundle tenacity into the yam tenacity.

• Proceedings of the KIEE Conference
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• 2001.07e
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• pp.7-12
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• 2001

A large number of methods for the design optimization have been proposed in recent years. However, it is not easy to apply these methods to practical use because of many iterations. So, in the design optimization, physical and engineering investigation of the given model are very important, which results in an overall increase in the optimization speed. This paper describes a novel optimization procedure utilizing the conformal transformation method. This approach consists of two phases and has the advantage of grasping the physical phenomena of the model easily. Some numerical results that demonstrate the validity of the proposed method are also presented.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1990.10a
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• pp.63-68
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• 1990

The nature of fluctuating air pressure inside building was studied by testing a building model in a wind tunnel. The model has a single room and a sin81e window opening. Various opening conditions were tested in both laminar uniform wind and turbulent boundary-layer wind. The RMS and the spectra of the fluctuating internal pressure were measured. The test results support a recent theory which predicts the behavior of internal pressure under high wind based on aerodynamic analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1115-1121
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• 2003

The vibration isolation table system for the high precision Processing machinery has been developed. The system uses air spring as its isolation elements. An investigation of the model and the test results showed that the diaphragm has a role in the mathematical model. The vibration levels at various floors in the laboratory were investigated during operating the large shaking table for the selection of optimum installation location. The vibration test on the designed system showed good isolation performances.