• Journal of Astronomy and Space Sciences
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• v.31 no.4
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• pp.347-351
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• 2014

Planetary exploration rovers are likely to make a trip on a winding and sloping road of irregular surfaces to the destination in order to accomplish scientific missions. One of the key technologies for rovers is a suspension for traveling and performing exploration missions; the suspension is an essential area of technology for a stable movement of a rover. In this study, an 8-wheel suspension is designed to enable efficient climbing of slopes on a passage to the destination. For the two front wheels among the eight wheels, the moment at the pivot connecting two wheels is derived when the distance between the wheels and the torque of wheels are same. A test experiment was performed to compare the magnitude of moment according to the change in tilt angle and the position of the pivot. Finally, a suspension design considering the position of the pivot was proposed to enhance the hill-climbing performance.

• International Journal of Aeronautical and Space Sciences
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• v.12 no.4
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• pp.318-330
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• 2011

This paper investigates the convergence characteristics of the modified artificial compressibility method proposed by Turkel. In particular, a focus is mode on the convergence characteristics due to variation of the preconditioning factor (${\alpha}_u$) and the artificial compressibility (${\beta}$) in conjunction with an upwind method. For the investigations, a code using the modified artificial compressibility is developed. The code solves the axisymmetric incompressible Reynolds averaged Navier-Stokes equations. The cell-centered finite volume method is used in conjunction with Roe's approximate Riemann solver for the inviscid flux, and the central difference discretization is used for the viscous flux. Time marching is accomplished by the approximated factorization-alternate direction implicit method. In addition, Menter's k-${\omega}$ shear stress transport turbulence model is adopted for analysis of turbulent flows. Inviscid, laminar, and turbulent flows are solved to investigate the accuracy of solutions and convergence behavior in the modified artificial compressibility method. The possible reason for loss of robustness of the modified artificial compressibility method with ${\alpha}_u$ >1.0 is given.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.4
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• pp.207-210
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• 2012

Genetic algorithms(GA) are well known and very popular stochastic optimization algorithm. Although, GA is very powerful method to find the global optimum, it has some drawbacks, for example, premature convergence to local optima, slow convergence speed to global optimum. To enhance the performance of GA, this paper proposes an adaptive partitioning-based genetic algorithm. The partitioning method, which enables GA to find a solution very effectively, adaptively divides the search space into promising sub-spaces to reduce the complexity of optimization. This partitioning method is more effective as the complexity of the search space is increasing. The validity of the proposed method is confirmed by applying it to several bench mark test function examples and the optimization of fuzzy controller for the control of an inverted pendulum.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.9
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• pp.1-11
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• 2004

A comprehensive study has been made for the investigation of the convergence and stability characteristics of the LU scheme for solving the Euler equations on unstructured meshes. The von Neumann stability analysis technique was initially applied to a scalar model equation, and then the analysis was extended to the Euler equations. The results indicated that the convergence rate is governed by a specific combination of flow parameters. Based on this insight, it was shown that the LU scheme does not suffer any convergence deterioration at all grid aspect ratios, as long as the local time step is defined using an appropriate parameter combination.

• The Pure and Applied Mathematics
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• v.9 no.1
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• pp.39-45
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• 2002

In this paper, we study the space of almost continuous functions with the topology of uniform convergence. And we investigate some properties of this space.

• Communications of the Korean Mathematical Society
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• v.30 no.3
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• pp.169-176
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• 2015

A sequence of composition operators on Hardy space is considered. We prove that, by numerical range properties, it is SOT-convergence but not converge.

• Proceedings of the Korea Society of Design Studies Conference
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• 2005.05a
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• pp.114-115
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• 2005

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.53-62
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• 2006

Two-dimensional steady flowfields generated by transverse injection jets into a supersonic mainstream are numerically simulated. Fine-scale turbulence effects are represented by a k-${\omega}$ SST two-equation closure model which includes $y^+$ effects on the turbulence model. Solution convergence is evaluated by using Grid Convergence Index(GCI), a measure of uncertainty of the grid convergence. Comparison is made with experimental data and other turbulence models in term of surface static pressure distributions, the length of the upstream separation region, and the penetration height. Results indicate that the k-${\omega}$ SST model correctly predicts the mean surface pressure distribution and the upstream separation length for low static pressure ratios. However, the numerical predictions become less consistent with experimental results as the static pressure ratio increases. All these results are taken within 1% error band of grid convergence.

• 한국정보교육학회:학술대회논문집
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• 2021.08a
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• pp.321-326
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• 2021

In this paper, the information education plan of the Ministry of Education and offices of education was analyzed in relation to the construction of the AI convergence education room. And based on this, an appropriate construction direction was suggested. For research, AI convergence education room construction plan, budget amount per school and etc were analyzed in the information education plan of the Ministry of Education, KERIS, KOFAC, and the plan of leading schools for AI education. Although the Ministry of Education is making various efforts to promote SW education and artificial intelligence convergence education, it is found that the number is far insufficient compared to the number of elementary, middle and high schools. Efforts to expand the information education room at the government level are continuously required, and in order to utilize the developed artificial intelligence convergence education room, it is necessary to provide abundant teaching and learning examples for the construction space model. In addition, school-level planning and execution must be followed so that the constructed space can be used appropriately, and management and maintenance plans for equipment are required.

• Journal of the Korea Convergence Society
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• v.11 no.1
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• pp.141-150
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• 2020

This paper studies the activities characteristics of the elderly aged 60-75 years old who can take care of themselves in the community public space, and puts forward the design principles of the community public space in the aging society. Using the methodology of experience design, through naturalistic observation, questionnaires, interviews and shadowing, the spatial and temporal characteristics of daily activities of the elderly are analyzed. In the community public space, the behavior of the elderly is essentially a social activity to get more attention and communication. This determines the needs, time, frequency and duration of activities of the elderly in community public space. In the community public space, the behavior of the elderly has the characteristics of long-term and regularity, and its behavior changes slightly with the space, the objective factors that affect the elderly are gender, age and climate. The subjective factors are lifestyle, family members and income level.