• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.220-225
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• 2003

Recent issue of optical actuator is applying to mobile device. It leads actuator to become smaller than conventional type. This paper proposes the design of micro actuator plate spring and analysis of its vibration characteristic. Considering natural frequency of spindle motor, 1st and 2nd eigenfrequency of micro actuator must avoid its natural frequency. First, magnetic circuit is designed by using fine pattern coil and magnetic force is acquired by simulation program. Then, concept design is achieved by topology optimization. From concept design, micro actuator plate spring is embodied through DOE(design of experiment). Finally, considering vibration characteristic simultaneously, optimal plate spring design is determined by RSM(response surface method).

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.17 no.2
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• pp.129-138
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• 2013

A spatio-temporal models as systems of ODE which describe two-species Beddington - DeAngelis type predator-prey system living in a habitat of two identical patches linked by migration is investigated. It is assumed in the model that the per capita migration rate of each species is influenced not only by its own but also by the other one's density, i.e. there is cross diffusion present. We show that a standard (self-diffusion) system may be either stable or unstable, a cross-diffusion response can stabilize an unstable standard system and destabilize a stable standard system. For the diffusively stable model, numerical studies show that at a critical value of the bifurcation parameter the system undergoes a Turing bifurcation and the cross migration response is an important factor that should not be ignored when pattern emerges.

• Structural Engineering and Mechanics
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• v.31 no.2
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• pp.153-162
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• 2009

The reduction of the dynamic response of an offshore structure subjected to wind-generated random ocean waves is of extreme significance in the aspects of serviceability, fatigue life and safety of the structure. In this study, a new neuro-control scheme is applied to the vibration control of a fixed offshore platform under random wave loads to examine the applicability of the proposed method. It is called the Lattice Probabilistic Neural Network (LPNN), as it utilizes lattice pattern of state vectors as the training data of PNN. When control results of the LPNN are compared with those of the NN and PNN, LPNN showed better performance in effectively suppressing the structural responses in a shorter computational time.

• The Korean Journal of Applied Statistics
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• v.25 no.6
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• pp.933-945
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• 2012

In this paper we used the KLIPS(Korean Labor and Income Panel tudy) data that surveyed from 2006(wave 9) to 2009(wave 12). Other previous studies are concerned with the panel attrition in the early wave, but this study classifies the response pattern and investigates some factors that influence panel attrition when the panel tends to stabilize. It was revealed that panel attrition was influenced by relocation and housing type through the logit model. Besides it was appeared that panel attrition was affected by the monthly living expenses and the overall household income through the decision tree.

• Journal of Mechanical Science and Technology
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• v.19 no.7
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• pp.1517-1525
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• 2005

Liquid sloshing displays the highly nonlinear free surface fluctuation when either the external excitation is of large amplitude or its frequency approaches natural sloshing frequencies. Naturally, the accurate tracking of time-varying free surface configuration becomes a key task for the reliable prediction of the sloshing time-history response. However, the numerical instability and dissipation may occur in the nonlinear sloshing analysis, particularly in the long-time beating simulation, when two simulation parameters, the relative time-increment parameter a and the fluid mesh pattern, are not elaborately chosen. This paper intends to examine the effects of these two parameters on the potential-based nonlinear finite element method introduced for the large amplitude sloshing flow.

• Journal of Biomedical Engineering Research
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• v.27 no.1
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• pp.22-29
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• 2006

This paper proposes an efficient array beamforming method using spatial matched filtering for ultrasound imaging. In the proposed method, ultrasound waves are transmitted from an array subaperture with fixed transmit focus as in conventional array imaging. At receive, radio frequency (RF) echo signals from each receive channel are passed through a spatial matched filter that is constructed based on the system transmit-receive spatial impulse response. The filtered echo signals are then summed. The filter remaps and spatially registers the acoustic energy from each element so that the pulse-echo impulse response of the summed output is focused with acceptably low side lobes. Analytical beam pattern analysis and simulation results using a linear array show that the proposed spatial filtering method can provide more improved spatial resolution and contrast-to-noise ratio (CNR) compared with conventional dynamic receive focusing (DRF) method by implementing two-way dynamically focused beam pattern throughout the field.

• International Journal of Ocean System Engineering
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• v.3 no.3
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• pp.158-163
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• 2013

The acoustic target strength (TS) is one of the most important parameters for a submarine's stealth design. Because modem submarines are larger than their predecessors, TS must be managed at each design stage in order to reduce it. To predict the TS of a submarine, TASTRAN R1 was developed based on a Kirchhoff approximation in a high-frequency range. This program can present TS values that include multi-bounce effect in the exterior and interior of the structure by combining geometric optics (GO) and physical optics (PO) methods, anechoic coating effect by using the reflection coefficient, and response time pattern for a detected target. In this paper, TS calculations for a submarine model with the above effects are simulated by using this developed program, and the TS results are discussed.

• International Journal of Computer Science & Network Security
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• v.22 no.3
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• pp.292-302
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• 2022

The radar tomographic imaging is based on the Radar Cross-Section "RCS" of the materials of a shape under examination and investigation. The RCS varies as the conductivity and permittivity of a target, where the target has a different material profile than other background objects in a scene. In this research paper, we use Hierarchical Performance Modeling "HPM" and a framework developed earlier to determine/spot bottleneck(s) for pattern recognition of materials using a combination of the Single Layer Perceptron (SLP) technique and tomographic images in radar systems. HPM provides mathematical equations which create Objective Functions "OFs" to find an average performance metric such as throughput or response time. Herein, response time is used as the performance metric and during the estimation of it, bottlenecks are found with the help of OFs. The obtained results indicate that processing images consumes around 90% of the execution time.

• Korean Journal of Childcare and Education
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• v.11 no.1
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• pp.153-171
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• 2015

The purposes of this study were to explore the relations of preschoolers' narrative representation profile types to diurnal cortisol regulation pattern at home. Fourteen story stems from the MacArthur Story Stem Battery (MSSB, Bretherton, et al., 1990) were administered to 40 preschoolers(22 boys, 18 girls, aged 5) recruited from 8 kindergartens in the Seoul and Gyeonggi areas. And also, their saliva cortisol was collected. The children's responses were aggregated into 5 dimensions, based on content themes and performance scores, which included emotions expressed and narrative coherence using the MacArthur Narrative Coding System(Robinson, et al., 2004). Data were analyzed by means of cluster analysis. Five response profiles emerged over the course of this research: Prosocial, Anxiety, Dyregulated aggression, Restricted, and Avoidance profiles. Cortisol at home showed decrease diurnal cortisol regulation patterns, however it showed a difference according to narrative response profiles. Restricted, Prosocial, and Avoidance profiles showed decrease diurnal cortisol regulation patterns. Anxiety profiles showed flat pattern, and Dyregulated aggression profile showed rising diurnal cortisol regulation pattern. These results show the preschoolers' internal representation may affect the diurnal cortisol reaction in daytime.

• The Journal of the Korea Contents Association
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• v.14 no.12
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• pp.629-638
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• 2014

Objective of this study is to be utilized as foundational data of expression methods and to increase children's dream and imagination by researching and analyzing differences of imaginative reaction from patterns of imaginative activities and verbal response for the expressive methods of illustrations. Study subjects are 253 children aged from six to seven years old, and four different types of research tool of which are screens with simple pattern, realistic pattern, omitted pattern and indirect pattern has been used in the empirical survey conducted over two times. Result from provided research tools has shown that difference of diversity can be observed from patterns of imaginative activities and verbal reaction patterns. Especially, in terms of imaginative activities, structural and creative imagination responses can be observed from screens with simple, omitted patterns and indirect and metaphorical patterns compares to screens with simple patterns and direct, realistic patterns, and positive affection to children's dream and creativity and imagination can be found from the result of high imaginative response observed from patterns of verbal reaction.