• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.37-39
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• 2002

The model of terminal cryostat for HTS power cable is conceptually designed. In this paper we defined that heat loads of the terminal cryostat was only cooled by the liquid nitrogen without cooling gas. Total heat loss calculated by analytical and numerical methods are 46.4W at 0A and 69W at 1260A for the 3-Phase HTS power cable system of 50MW, 22.9kV.

• Structural Engineering and Mechanics
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• v.10 no.3
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• pp.289-298
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• 2000

Based on the two-dimensional constitutive relationship of the piezoelastic material, this paper derived an analytic solution to the elastic beam with the piezoelectric layer under the electric field, presented the explicit expressions of its displacement and stress. It is helpful for understanding the electrical and mechanical behavior of piezoelectric materials as actuators and the validation of the numerical methods such as FEM.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.3
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• pp.225-232
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• 2018

This paper proposed the optimization method of the extremely low numerical-dispersion finite-difference time-domain (ELND-FDTD) method based on the H(2,4) scheme for wideband and extremely accurate electromagnetic properties of lossy material, which has a constant conductivity and relative permittivity. The optimized values of three variables are calculated for the minimum numerical dispersion errors of the proposed FDTD method. The excellent accuracy of the proposed method is verified by comparing the calculated results of three different FDTD methods and the analytical results of the two-dimensional dielectric cylinder scattering problem.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.40-45
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• 1994

The TCAD(Technology Computer Aided Design) software tool is a popular name to be able to simulate the semiconductor process and device circuit. We have developed a two-dimensional TCAD software tool included an editor, parser, each process unit, and 2D, 3D graphic routine that is Integrated Environment. The initial grid for numerical analysis is automatically generated with the geometric series that use the user default(given) line and position separated with grid interval and the nodes corresponding to each mesh point stoic the all the possible attribute. Also, we made a data structure called PIF for input or output. Methods of ion implantation in this paper arc Monte Carlo, Gaussian Pearson and Dual-Pearson. Analytical model such as Gaussian, Pearson and Dual-Pearson were considered the multilayer structure and two-dimensional tilted implantation. We simuttaneously calculated the continuity equation of impurity and point defect in diffusion simulation. Oxidation process was simulated by analytical ERFC(Complementary Error Function) model for local oxidation.

• Smart Structures and Systems
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• v.21 no.3
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• pp.335-347
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• 2018

The fast-growing number of mobile and wearable applications has driven several innovations in small-scale electret-based energy harvesting due to the compatibility with standard microfabrication processes and the ability to generate electrical energy from ambient vibrations. However, the current modeling methods used to design these small scale transducers or microgenerators are applicable only for constant-speed rotations and small sinusoidal translations, while in practice, large amplitude sinusoidal vibrations can happen. Therefore, in this paper, we formulate an analytical model for electret-based microgenerators under general sinusoidal excitations. The proposed model is validated using finite element modeling combined with numerical simulation approaches presented in the literature. The new model demonstrates a good agreement in estimating both the output voltage and power of the microgenerator. This new model provides useful insights into the microgenerator operating mechanism and design trade-offs, and therefore, can be utilized in the design and performance optimization of these small structures.

• Steel and Composite Structures
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• v.32 no.5
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• pp.687-699
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• 2019

In this paper, free and force vibration behaviors of graphene-reinforced composite functionally graded (GRC-FG) cylindrical shells in thermal environments are investigated based on Reddy's third-order shear deformation theory (HSDT). The GRC-FG cylindrical shells are composed of piece-wise pattern graphene-reinforced layers which have different volume fraction. Based on the extended Halpin-Tsai micromechanical model, the effective material properties of the resulting nanocomposites are evaluated. Using the Hamilton's principle and the assumed mode method, the motion equation of the GRC-FG cylindrical shells is formulated. Using the time- and frequency-domain methods, free and force vibration properties of the GRC-FG cylindrical shell are analyzed. Numerical cases are provided to study the effects of distribution of graphene, shell radius-to-thickness ratio and temperature changes on the free and force vibration responses of GRC-FG cylindrical shells.

• 한국기계연구소 소보
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• s.17
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• pp.29-38
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• 1987

A mechanical linkage system to measure the operating temperature of the piston is developed and installed to the engine. Actual temperature distribution is measured for comparison with the numerical results. Heat transfer at the piston is analyzed using an FEM program. Thermal boundary condition of piston surface is determined by analytical and empirical methods. The temperature distribution and the thermal deformation are obtained by the FEM program.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.467-470
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• 1999

An analytical method based on the nonlinear layered finite element method is developed to simulate overall load-deflection behavior of bonded and unbonded prestressed concrete beams. The model which uses rather advanced numerical technique for iterative convergence to equilibrium can be regarded as superior one compared to the models mainly based on either load control or displacement control methods. Model predictions were compared with preceding experimental results and it was observed that there were good agreements between them.

• Architectural research
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• v.14 no.1
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• pp.27-33
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• 2012

This study proposes analytical methods to establish the eigenfunction of continuous system due to substructuring and decoupling of discrete subsystems. The dynamic characteristics of updated continuous system are evaluated by the constraint effect of consistent deformation at the interfaces between two systems. Beginning with the dynamic equation for constrained discrete system, this work estimates the modal eigenmode function for the continuous system due to the addition or deletion of discrete systems. Numerical applications illustrate the validity and applicability of the proposed method.

• Communications for Statistical Applications and Methods
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• v.23 no.1
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• pp.85-91
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• 2016

Aggregate claim amounts with a large claim frequency represent a major concern to automobile insurance companies. In this paper, we show that a new hybrid method to combine the analytical saddlepoint approximation and Monte Carlo simulation can be an efficient computational method. We provide numerical comparisons between the hybrid method and the usual Monte Carlo simulation.