• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.37-39
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• 1999

In this paper, the magnetic fluid linear pump is designed. Inside the small tube, magnetic fluid is shielded with thin rubber protector. The magnetic fluid activated by traveling pulses of magnetic field drags the water inside the pump. The iterative algorithm for the shape of magnetic fluid is presented by using nonlinear finite element method and Navier-Stokes equations. The computed curvature of fluid under the magnetic field and the gravitational force is agreed well with photograph image. The dimension and electric configurations of the magnetic linear pump are optimized and the results are compared with measurements.

• Journal of Environmental Science International
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• v.28 no.11
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• pp.951-958
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• 2019

Seoullo7017, an elevated linear park, was created to redevelop obsolete road infrastructure as public space, which provides unique landscapes. This study was aimed to evaluate and suggest proper planting design for improving psychological benefits in Seoullo7017. Field survey and simulation experiment were carried out to investigate the user's perception on the landscapes. Many users had negative feelings of the present landscapes in Seoullo7017, due to concrete pavement and simple planting design using big concrete pots. Landscape simulation experiment showed this perception could change depending on planting design. In especial, herb species played an important role in improving the quality of landscape in a linear park and providing positive feelings such as refreshment, warmth and naturalness. This study suggested that planting design in a linear space needs to be focused rather on the planting style and species than the volume of greens.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.316-320
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• 2008

A light rail transit, using a linear induction motor, is generally composed with reaction plates along railroad track and the three phase primary on the vehicle. This linear induction motor is driven to keep clearance between the primary and the secondary of the ground for preventing any contact. Therefore efficiency and power factor is very low. In addition, the reaction plate installed on the ground throughout entire railway is impossible to keep uniform gap and it may cause system deterioration. In this paper, A rotary-type small-scale model of a linear induction motor for various characteristic analysis is designed. Thrust force, normal force and input current of the model by air-gap variation have been analyzed by using a Finite Element Method (FEM). The effects of air-gap variation on system performance have been considered by analysis results.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.36 no.1
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• pp.113-124
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• 2020

The purpose of this study is to suggest an improvement for the CPTED(Crime Prevention Through Environmental Design) guidelines for the urban linear park. We analysed the Changjeon-dong section of Gyeongui Line Forest Park into 12 sub-areas and evaluated CPTED design applied on the park based on analysis framework derived from 15 precedent studies by conducting on-site observations. Both surveys and in-depth interviews on users of the park were conducted and the results of analysis on the evaluation from users and the on-site observation were compared. We found that the lighting condition and the height of wall and trees at the park boundaries are very important to insure natural surveillance since the adjacent areas are easy to be hidden from passers-by and subject to invasion and threat of crime while protecting the privacy of residents on the boundary. There should be improvement on management facilities and crime prevention facilities for more safe and convenient use of the linear park and the adjacent commercial use during nighttime also need to be managed for conflicts between various type of users.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.106-109
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• 2008

Piecewise linear diode models are widely used for large-signal circuit analyses, especially power electronic circuit simulations. When using a piecewise linear diode model for simulation, a switching method to select a proper one among linear models is needed. The conventional switching method keeps the previous ON, OFF state information, and applies different switching conditions according to the state. However, this method has difficulties especially in extending to multi-piecewise linear models. This paper presents a switching method which appropriately divides the v-i plane into regions and select a linear model according to the region where the operating point(the voltage and the current of the diode) belongs. This switching method is easily extended to multi-Piecewise linear models. An example using the tableau analysis and the backward Euler integration is presented for verification.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.6
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• pp.641-646
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• 1999

This paper deals with the robust stability of discrete-time linear systems with time- varying delays and norm-bounded uncertainties. In this paper, the magnitude of time-varying delays is assumed to be upper-bounded. The sufficient condition is presented in terms of linear matrix inequality. It is also shown that the robust stability of uncertain discrete-time linear systems with time-varying delays is related with the quadratic stability of uncertain discrete-time linear systems with constant time delay.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.5
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• pp.380-386
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• 2015

Panel methods are useful tools for analyzing fluid-flow around a wing section. It has the advantage of fast and accurate calculation, compared to other CFD Methods such as RANS solvers. This paper suggests a piecewise linear panel method in order to improve accuracy of existing panel methods by changing the piecewise constant singularity strength to linear singularity strength(for dipole strength). The piecewise linear panel method adopts the linear distribution of singularity strength, while control point is located at the node of each panel. Formulation of the piecewise linear panel method is given, and some calculation results are shown for typical wing sections.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.4
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• pp.159-164
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• 2003

In this paper, a three-dimensional finite element method and construction of equivalent-circuit for a linear ultrasonic motor are presented. The validity of three-dimensional finite element routine in this paper is experimentally confirmed by analyzing impedance of a piezoelectric transducer. Using this confirmed finite element routine, impedance and vibration mode of a linear ultrasonic motor are calculated. Elliptical motion of contact point between vibrator and rail of the linear ultrasonic motor is shown for determination of contact points. By using the finite element method and analytic equations, characteristics of the linear ultrasonic motor, such as thrust force, speed, losses, powers and efficiency, are calculated. The results are confirmed by experiment. Finally, equivalent circuit parameters of the linear ultrasonic motor are obtained using the three-dimensional finite element method and analytic equations.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.273-276
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• 2008

Equivalent linear method indirectly reflects a variation of shear modulus(G/Gmax) and damping ratio $(\xi)$ by selects mean value of every response analysis. Existing equivalent linear method does not properly consider variation of shear strain along frequencies and uses mean value. Real dynamic soil behavior is affected by shear stiffness and damping ratio. Modified equivalent linear method is developed to consider variation. Modified equivalent linear method can reflects high strain at low frequency and low strain at high frequency by using an easement curve. This study presents propriety of method by case study.

• The Korean Journal of Applied Statistics
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• v.28 no.2
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• pp.353-360
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• 2015

Various statistical models have been proposed over the last decade for spatially correlated Gaussian outcomes. The spatial linear mixed model (SLMM), which incorporates a spatial effect as a random component to the linear model, is the one of the most widely used approaches in various application contexts. Employing link functions, SLMM can be naturally extended to spatial generalized linear mixed model for non-Gaussian outcomes (SGLMM). We review popular SGLMMs on non-Gaussian spatial outcomes and demonstrate their applications with available public data.