• Wind and Structures
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• v.31 no.2
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• pp.153-164
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• 2020

In the design of buildings, lateral loading is one of the most important factors considered by structural designers. The concept of performance-based design (PBD) is well developed for seismic load. Whereas, wind design is mainly based on elastic analysis for both serviceability and strength. For tall buildings subject to extreme wind load, inelastic behavior and application of the concept of PBD bear consideration. For seismic design, current practice primarily presumes inelastic behavior of the structure and that energy is dissipated by plastic deformation. However, due to analysis complexity and computational cost, calculations used to predict inelastic behavior are often performed using elastic analysis and a response modification factor (R). Inelastic analysis is optionally performed to check the accuracy of the design. In this paper, a framework for application of an R factor for wind design is proposed. Theoretical background on the application and implementation is provided. Moreover, seismic and wind fatigue issues are explained for the purpose of quantifying the modification factor R for wind design.

• Steel and Composite Structures
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• v.42 no.1
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• pp.59-74
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• 2022

This study introduces a general reliability-based, performance-based design framework to design frames regarding their uncertainties and user-defined design goals. The Iterative-R method extracted from the main framework can designate a proper R (i.e., response modification factor) satisfying the design goal regarding target reliability index and pre-defined probability of collapse. The proposed methodology is based on FEMA P-695 and can be used for all systems that FEMA P-695 applies. To exemplify the method, multiple three-dimensional, four-story steel special moment-resisting frames are considered. Closed-form relationships are fitted between frames' responses and the modeling parameters. Those fits are used to construct limit state functions to apply reliability analysis methods for design safety assessment and the selection of proper R. The frameworks' unique feature is to consider arbitrarily defined probability density functions of frames' modeling parameters with an insignificant analysis burden. This characteristic enables the alteration in those parameters' distributions to meet the design goal. Furthermore, with sensitivity analysis, the most impactful parameters are identifiable for possible improvements to meet the design goal. In the studied examples, it is revealed that a proper R for frames with different levels of uncertainties could be significantly different from suggested values in design codes, alarming the importance of considering the stochastic behavior of elements' nonlinear behavior.

• The Research Journal of the Costume Culture
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• v.31 no.6
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• pp.756-775
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• 2023

This study was aimed at examining the characteristics of women's blue denim on the basis of design elements to provide fundamental data for fashion majors and fashion designers. Seven design elements were selected from previous studies to compare them with the following characteristics of blue denim: color (washing, dyeing), ornamentation (trimming, detailing, painting, and printing), and form modification, tearing, and ripping). Data from 1,520 photographs of the 2019 S/S to the 2023-24 F/W collections were collected through overlapping checks. The data were then subjected to frequency analysis using the Statistical Package for the Social Sciences (version 26). The results are as follows: The most frequent design method used in producing the denim items in our sample was washing, followed by modification, tearing, and ripping and detailing. The greatest change in denim design occurred in 2023, and more design element changes were observed in the F/W season than in the S/S season. Washing was used four times or more frequently than dyeing, while detailing was employed approximately 2 times more often than trimming. With respect to form, the most common approach was modification, followed by tearing and ripping.

• Korean Institute of Interior Design Journal
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• v.26 no.1
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• pp.25-32
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• 2017

As the elderly population increases rapidly, existing houses many elderly reside are under poor conditions that they work as a factor to impede on the independent living of elderly people. Thus, improving existing housing environment to suit the needs of elderly life has been required. Academics has been continuously researched on the field considering the importance of elderly housing modification and the importance on the research of this field is projected to be greater with the coming of aging society. Hence, this study has a purpose on analyzing trends of previous studies related to housing modification for the elderly published in Korean academic journals in depth. This study is a content analysis study and analyzed the trend of previous studies with academic journal field, purpose of study, research subject, research area, research method, research content as analysis categories. As a result, previous studies was published the most in natural science academic journals and main stream of research was to suggest direction of housing modification by conducting surveys on actual conditions and needs of single elderly families and to suggest improving the directions of policies related to modification. On the other hand, empirical studies needed to execute housing modification such as standard and method of housing modification and supporting tools are still at minimal level that researches on this field should be conducted additionally. This study is expected to be used as basis to examine the current state of previous studies on housing modification for the elderly and to seek further research directions.

• Journal of the Korean Society of Costume
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• v.62 no.7
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• pp.97-116
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• 2012

The purpose of this study is to analyze the trench coat designs shown in the latest collection by using a checklist method among many fashion design idea methods and then investigate the trend of trench coat design in multilateral directions. As for the research method, 1,307 photos selected from the photos of women's trench coats publicized from 2006 until 2011 were used for the analysis and then a frequency analysis was conducted. As a result, the types of checklist methods shown in trench coats included modification type, elimination type, conversion type, combination type, minimization type, addition type, and magnification type. In the modification type, the modification of color to the back side stood out; in the elimination type, the design eliminating epaulet stood out ; in the conversion type, conversion to jacket among many items stood out. In the combination type, the combination between different material texture and identical colors among colors stood out ; in the minimization type, the design minimizing sleeves stood out; in the addition type, the addition of sleeves among many details stood out ; in the magnification type, the design magnifying panels stood out.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.859-864
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• 2001

For earthquake resistance design, a response modification factor is used to reduce the design strength and it reflects ductility, reserve strength, redundancy and damping effect. But this factor has not theoretical basis. In this study, two response modification factors are compared and analyzed for shear wall apartment building.; the one is introduced by ATC-19 Procedures, the other is suggested FEMA-273 and ATC-40 through nonlinear static analysis. For the results, ATC-19 procedure gives a reasonable estimation to R factor. But $R_{u}$ by using FEAM-273 and ATC-40 methods is estimated so small in case of a minor or moderate earthquake region. Due to this fact, response modification factor is smaller than suggested load criterion 3.0. So, it needs to decrease wall volume and reduce the global strength and system stiffness for proper ductile behavior matching to domestic load criterion.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.816-819
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• 2002

This paper is the study on stress analysis for tooth modification of high speed gear using a finite element method. Gear drives constitute very important mechanisms in transmitting mechanical power processes compromising several cost effective and engineering advantages. The load transmission occurred by the contacting surfaces arises variable elastic deformations which are being evaluated through finite element analysis. The automatic gear design program is developed to model gear shape precisely. This gear design system developed was used by pre-processor of FEM packages. The distribution of stresses at contacting surfaces was examined when gear tooth contacts. And this paper proposes method for the tooth modification after carrying out stress analysis using a finite element method.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.162-167
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• 2003

This paper is the study on stress analysis for tooth modification of high speed gear using a finite element method. Gear drives constitute very important mechanisms in transmitting mechanical power processes which compromise several cost effective and engineering advantages. The load transmission which occurred by the contacting surfaces arises variable elastic deformations evaluated through finite element analysis. The automatic gear design program was developed to model gear shape precisely. This developed gear design system was used by pre-processor of FEM packages. The distribution of stresses at contacting surfaces was examined when gear tooth contacts. And this paper proposes a method for the tooth modification after carrying out stress analysis using a finite element method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.9 s.90
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• pp.801-810
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• 2004

Parameter modification of a linear finite element model(FEM) based on modal sensitivity matrix is usually performed through an effort to match FEM modal data to experimental ones. However, there are cases where this method can't be applied successfully; lack of reliable modal data and ill-conditioning of the modal sensitivity matrix constitute such cases. In this research, a novel concept of introducing feedback loops to the conventional modal test setup is proposed. This method uses closed-loop natural frequency data for parameter modification to overcome the problems associated with the conventional method based on modal sensitivity matrix. We proposed the whole procedure of parameter modification using the closed-loop natural frequency data including the modal sensitivity modification and controller design method. Proposed controller design method is efficient in changing modes. Numerical simulation of parameter estimation based on time-domain input/output data is provided to demonstrate the estimation performance of the proposed method.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.1
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• pp.65-72
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• 2009

‘Korean Highway Bridge Design Code’ provides the spectrum analysis method with response modification factors for the seismic design of typical bridges. However, considering that korean peninsula is classified as moderate seismic regions and domestic circumstances for bridge design and construction are different from other countries, the applicability of this code is not yet proved. Therefore it is required to verify that applying the spectrum analysis method fulfills the no collapse requirement which is set forth as the basic seismic design concept. In this study two typical bridges with T and ${\prod}$ type piers are selected as analysis bridges and seismic designs are carried out by applying the spectrum analysis method with design conditions given for moderate seismic regions. Based on the results obtained through deign procedures, the role of the response modification factors and fulfillment of the no collapse requirement are discussed, from which supplementary provisions for the design code are identified.