• Fashion & Textile Research Journal
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• v.13 no.5
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• pp.686-694
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• 2011

The purpose of this study was to understand the preferences of the uniform design for the preschool student's parents. 97 parents became subjects for the research and questionaries were analysed by distribution of frequency and percentage using SPSS V. 18.0. The results of this study could be summarized as followings. First, most of the parents preferred to wearing preschool uniform and expected further improvement in function, material and design. Second, the preferred form was semi formal style consisting of shirt, knit vest, knit cardigan, and coat. Third, the preferred colors were the mixing together bright colors and quiet colors in vivid and pastel tone. Fourth, functional materials to comfort in children's physical activities and to serve convenience in cleaning were preferred. In Conclusion, the preferred design characteristics were combined function to enhance comfort and convenience in children's physical activities with esthetics to present loveliness and modesty as preschool students.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.288-294
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• 2010

In recent years, wind energy has been the world's fastest growing source of energy. This paper describes the structural design and analysis of composite blade for 2 kW-level HAWT (horizontal axis wind turbine). The aerodynamic design and force, which are required to design and analyze a composite blade structurally, are calculated through BEMT(blade element momentum theory) implemented in public code PROPID. To obtain the equivalent material properties of filament wound composite blades, the rule-of-mixture is applied using the basic material properties of fiber and matrix, respectively. Lay-up sequence, ply thickness and ply angle are designed to satisfy the loading conditions. Structural analysis by using commercial software ABAQUS is performed to compute the displacement and strength ratio of filament wound composite blades.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.852-859
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• 1994

Optmal topology design is to search the optimal layout of the structure which can be used fot the shape of the conceptual design stage. Our objective is to maximize the stiffness of the structure under a material usage constraint. The density of each finite element is the design variable and its relationship with Young's modulus is expressed by quadratic form. The shape is represented by the entire density distribution, the structural analysis is performed by finite element method and the optimization is achieved by feasible direction method. Unlike optimality criteria method,feasible direction method can handle various problems simultaneously, that is, multi- objectives and multi-constraints. Total optimization time can be reduced by the approximation of the material property and fewer design variables than homogenization method. Topology optimization is applied to design the shape of ribs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.320-323
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• 2002

This paper discusses process design of cold forging for inner tooth part, drum clutch. In respect to high productivity, low material consumption and low piece production costs, Metal forming has more merits than machining process. Net shape forming is huh technology which satisfies merits of metal forming and achieves high accuracy. Recently, net shape forming method widely applied because of high productivity, low material consumption and low piece production costs using press. In this study, the method which accuracy of drum clutch, automatic transmission pin, can be improved is discussed. First, process variables for process design of drum clutch are selected, and then process design is accomplished using forming analysis method. from forming analysis, forming load, stress, unfiling part is obtained. and comparing these results, optimal process design can be determined.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.224-232
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• 1999

Topology optimization has evolved into a very efficient concept design tool and has been incorporated into design engineering processes in many industrial sectors. In recent years, topology optimization has become the focus of structural design community and has been researched and applied widely both in academia and industry. There are mainly tow approaches for topology optimization of continuum structures ; homogenization and density methods. The homogenization method is to compute is to compute an optimal distribution of microstructures in a given design domain. The sizes of the micro-calvities are treated as design variables for the topology optimization problem. the density method is to compute an optimal distribution of an isotropic material, where the material densities are treated as design variables. In this paper, the density method is used to formulate the topology optimization problem. This optimization problem is solved by using an optimality criteria method. Several example problems are solved to show the usefulness of the present approach.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.135-138
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• 2005

HDL(Hardware Description Language) is the most important modem tools used to describe hardware, and becomes important as we move to higher levels of abstraction. The HDL has been made brisk use of in analog design, MEMS device[1-2], process related field as well as digital design. The most important characteristics of HDL is Abstraction which is the strongest tool that extend greatly designer's design ability. In this paper by the Modelling Continuum with hierarchical structure of abstraction, we apply UML(Unified Modeling Language) to SoC Design with HDL UML makes an easy and visual description of the various levels of abstraction, and gives designers good flexible modeling capabilty for SoC Design.

• Transactions of Materials Processing
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• v.12 no.7
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• pp.615-622
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• 2003

In the automobile industry, the design of optimal blank shape becomes a significant part of the stamping. It provides many evident advantages, sush as enhancement of formability, reduction of material cost and product development period. However, the nesting process, required for the optimal usage of materials in the blanking becomes more complicated as the blank shape becomes complicated, like most optimal blank shape. In this study, stamping process optimization system for the optimal usage of material has been developed through the integration of optimal blank design and optimal nesting. For optimal blank design, a radius vector method, the modified version of the initial nodal velocity method, the past work of the present author, have been proposed. Both the optimal blank design and optimal nesting programs have been developed under the GUI environment for the convenience of engineers. The efficiency of the optimization system has been verified with some chosen problems.

• International Journal of Aerospace System Engineering
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• v.6 no.1
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• pp.1-7
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• 2019

In the present study, structural safety and stability on the main wing and tail planes of the 1.2 ton WIG(Wing in Ground Effect) flight vehicle, which will be a high speed maritime transportation system for the next generation, was performed. The carbon-epoxy composite material was used in design of wing structure. The skin-spar with skin-stressed structural type was adopted for improvement of lightness and structural stability. As a design procedure for this study, the design load was estimated with maximum flight load. From static strength analysis results using finite element method of the commercial codes. From the stress analysis results of the main wing, it was confirmed that the upper skin structure between the second rib and the third rib was unstable for the buckling load. Therefore in order to solve this problem, three stiffeners at the buckled region were added. After design modification, even though the weight of the wing was a little bit heavier than the target weight, the structural safety and stability was satisfied for design requirements.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.7
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• pp.66-77
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• 1996

Optimal topology design is to search the optimal configuration of a structure which can be used as a shape at the conceptual design stage. Our objective is to maximize the stiffness of the structures and ribs under a material usage constraintl. The density of each finite element is the design variable and its relationship with Young's modulus is expressed by quadratic form. The configuration is represented by the entire density distribution, the structural analysis is performed by finite element method and the optimiza- tion is performed by Feasible Direction Method. Feasible Direction Method can handle various problems simultaneously, that is, mult-objectives and multi-constraints. Total computation time can be reduced by the quadratic relationship between the density and the material property and fewer design variables than Homogenization Method. Toplogy optimization technique developed in this research is applied to design the shapes of the ribs.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.362.1-362
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• 2002

Eigenvalues are taken as performance criteria for structural damping design using viscoelastic material. Given material properties, optimal distribution of damping material is sought based on eigenvalue sensitivity. For eigenanalysis of frequency dependent viscoelastic material rented structures, Golla-Hughes-McTavish(GHM) model is used and some dominant modes are chosen for consideration. (omitted)