• Steel and Composite Structures
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• v.21 no.6
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• pp.1389-1410
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• 2016

This paper proposes a hybrid of topological derivative-based level set method (LSM) and isogeometric analysis (IGA) for structural topology optimization. In topology optimization a significant drawback of the conventional LSM is that it cannot create new holes in the design domain. In this study, the topological derivative approach is used to create new holes in appropriate places of the design domain, and alleviate the strong dependency of the optimal topology on the initial design. Furthermore, the values of the gradient vector in Hamilton-Jacobi equation in the conventional LSM are replaced with a Delta function. In the topology optimization procedure IGA based on Non-Uniform Rational B-Spline (NURBS) functions is utilized to overcome the drawbacks in the conventional finite element method (FEM) based topology optimization approaches. Several numerical examples are provided to confirm the computational efficiency and robustness of the proposed method in comparison with derivative-based LSM and FEM.

• Journal of Electrical Engineering and Technology
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• v.11 no.5
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• pp.1202-1209
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• 2016

• Korean Journal of Computational Design and Engineering
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• v.12 no.3
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• pp.182-192
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• 2007

The reduction of product development time is exposed to the competitive pressure due to shortened product-and production technology lifecycles as well as increasingly dynamic markets. Specially in automobile companies, that is of major importance for designing die because it is a bottleneck process in the development of a new car. To improve this conventional design process, this paper describes how to design it fast and flexibly. This was done by a modular method using standard template and a feature and knowledge based design method along the design process.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.12 no.1
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• pp.56-61
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• 2016

After Japanese Fukushima nuclear power plant accident caused by the beyond design basis earthquake and tsunami, it has turned to be a major challenge for nuclear safety. IAEA, US NRC and EU have provided new safety design standards for beyond design basis event, Domestic regulatory bodies have also enacted guidances for licensees and applicants on additional methods related to beyond design basis events. This paper describes several evaluation methods for applying to nuclear power plants piping for beyond design basis earthquake. As a results, energy method based on the absorbed energy on nuclear power plant, deterministic method following design code and theory, experience method considering past earthquake data and information and probabilistic methods similar to probabilistic risk assessment were reviewed.

• International Journal of Contents
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• v.10 no.2
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• pp.42-46
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• 2014

This study suggests a teaching-learning method to improve creative design abilities of students majoring in design. By suggesting a creative design-inducing (CDI) teaching-learning method process and a creative design-inducing (CDI) teaching-learning method, this study aims to expand creative thinking among students with the aim of producing produce creative output as well as improving the effectiveness of design teaching. It also presents a case of the teaching-learning method in a design-related department, the process of teaching where the new method is applied is also examined. The teaching method this study suggests has the following merits: First, it allows the teacher to use various tools depending on the creative thinking abilities of individuals. By providing students with custom-made teaching, the method motivates and focuses students during the lesson. Second, it is easier for students to generate creative ideas than with other teaching methods.

• Wind and Structures
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• v.29 no.6
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• pp.489-497
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• 2019

Wind-adaptable design (WAD) provides a new method for super-tall buildings to lessen design conflicts between architectural prerequisites and aerodynamic requirements, and to increase the efficiency of structural system. Compared to conventional wind-resistant design approach, the proposed new method is to design a building in two consecutive stages: a stage in normal winds and a stage during extreme winds. In majority of time, the required structural capacity is primarily for normal wind effects. During extreme wind storms, the building's capacity to wind loads is reinforced by on-demand operable flow control measures/devices to effectively reduce the loads. A general procedure for using WAD is provided, followed by an exploratory case study to demonstrate the application of WAD.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.11
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• pp.1100-1107
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• 2004

In this paper, a new design method fur tapped coupled-line filters has been developed. The design equations for this tapped-line filter have been obtained using a new equivalent circuit model of tapped lines. These tapped-lines replace input/output coupled lines of the conventional edge coupled-line filters, which tend to have very narrow line gaps(few mils). Therefore, tapped coupled-line filters tend to be less sensitive to filter fabrication tolerances and to be easily fabricated using milling tools. The new filter design algorithm allows very accurate filter design for frequencies up to 20 GHz and bandwidth less than 20 %.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.777-784
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• 2010

In the current Korean seismic design guide, the site classification and the corresponding site coefficients were determined based on the UBC-1997 (Uniform Building Code). In order to develop the current site classification system, it is important to compare the local site conditions in Korea to other countries which have similar seismic design guides. In the eastern United States, New York City(40degrees 45minutes north latitude, 73degrees 59minutes west longitude) suggested that current design guidelines are unsuitable to shallow bedrock depth sites. So the 3-parameter methods are performed for new criteria in New York City. In this study, site response analyses were performed at 181 study sites using one-dimensional equivalent linear to evaluate the site-specific earthquake ground motions at inland areas in the Korean peninsula and reclassify the results according to similar ground motions using the 3-parameter methods. It is effective that multi-parameter methods for Korean site characteristics in comparison with single parameter method.

• Journal of Ocean Engineering and Technology
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• v.28 no.2
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• pp.147-151
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• 2014

This research presents a method for the initial structural design of a multi-megawatt wind turbine blade. The structural data for a 2-MW blade were applied as the blade structural characteristic data of the reference blade. Tenkinds of blade models were newly designed by replacing the spar cap axial GRRP with a GFRP and CFRP These terms should be defined. at different orientations. The axial stiffness coefficients of the newly designed models were made equal to the coefficient of the reference blade. The required numbers of layers in each section of blades were calculated, and the lay-up designs were based on these numbers. Verification results showed that the design method that used the structural data of the reference blade was appropriate for the initial structural design of a wind turbine blade.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.82-86
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• 1989

In this paper, digital autopilot design methods are investigated and a new method is suggested in order to improve existing problems. The method is based on .delta. transform (1) and overcome numerical problems occurring in the process of discretization. We illustrate design procedures using .delta. transform and suggest a hardware and software structure for digital autopilot implemented by microprocessor.