• 한국CDE학회논문집
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• 제11권1호
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• pp.27-40
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• 2006

The exchange of parameterized feature-based CAD models is important for product data sharing among different organizations and automation systems. The role of feature-based modeling is to gonerate the shape of product and capture design intends In a CAD system. A feature is generated by referring to topological entities in a solid. Identifying referenced topological entities of a feature is essential for exchanging feature-based CAD models through a neutral format. If the CAD data contains the modification history in addition to the construction history, a matching mechanism is also required to find the same entity in the new model (post-edit model) corresponding to the entity in the old model (preedit model). This problem is known as the persistent naming problem. There are additional problems arising from the exchange of parameterized feature-based CAD models. Authors have analyzed previous studies with regard to persistent naming and characteristics for the exchange of parameterized feature-based CAD models, and propose a solution to the persistent naming problem. This solution is comprised of two parts: (a) naming of topological entities based on the object spore information (OSI) and secondary name (SN); and (b) name matching under the proposed naming.

• 한국CDE학회논문집
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• 제16권3호
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• pp.178-186
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• 2011

Static CAD models are the CAD models that do not have feature information and modeling history. These static models are generated by translating CAD models in a specific CAD system into neutral formats such as STEP and IGES. When a CAD model is translated into a neutral format, its precious feature information such as feature parameters and modeling history is lost. Once the feature information is lost, the advantage of feature based modeling is not valid any longer, and modification for the model is purely dependent on geometric and topological manipulations. However, the capabilities of the existing methods to modify static CAD models are limited, Direct modification methods such as tweaking can only handle the modifications that do not involve topological changes. There was also an approach to modify static CAD model by using volume decomposition. However, this approach was also limited to modifications of protrusion features. To address this problem, we extend the volume decomposition approach to handle not only protrusion features but also depression features in a static CAD model. This method first generates the model that contains the volume of depression feature using the bounding box of a static CAD model. The difference between the model and the bounding box is selectively decomposed into so called the feature volume and the base volume. A modification of depression feature is achieved by manipulating the feature volume of the static CAD model.

• 디자인학연구
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• 제14권
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• pp.21-31
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• 1996

지난 30년 동안 빠른 경제발전에 따른 가정 생활의 서구화의 경향으로 한국의 기업들은 제품을 디자인하는데 있어서 현재 소비자(생활자)들이 무엇을 요구하고 있는지 파악하는데 어려움을 주고 있다. 본 연구에서는 도구환경이라는 접근방법을 통하여 이 문제에 대한 디자인 해결방안을 찾고자 하였다. 도구환경이란 제품환경의 확대된 개념으로 깁슨(Gibson, J. J.)의 개념을 인용한다면 인간 행위 목적을 달성하기 위한 모든 수단으로서 물질적인 것과 공간적인 것을 포함하고 있다. 이 접근 방법의 논리와 구조에 관하여는 디자인 방법론과 역사학, 사회심리학, 인간행동과학 등의 제 분야에 기초를 두고 논하였다. 특히 우리 나라의 식품의 보존저장을 위한 도구환경에 대해 선사시대이후 현재에 이르기까지 변화를 고찰한 후 미래의 도구환경을 예측하였다.

• Earthquakes and Structures
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• 제10권5호
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• pp.1125-1141
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• 2016

The direct displacement based design (DDBD) approach is spreading in the field of seismic design for many types of structures. This paper is carried out to present a robust approach for the DDBD procedure for single degree of freedom (SDOF) concentrically braced frames (CBFs). Special attention is paid to the choice of an equivalent viscous damping (EVD) model that represents the behaviour of a series of full scale shake table tests. The performance of the DDBD methodology of the CBFs is verified by two ways. Firstly, by comparing the DDBD results with a series of full-scale shake table tests. Secondly, by comparing the DDBD results with a quantified nonlinear time history analysis (NLTHA). It is found that the DDBD works relatively well and could predict the base shear forces ($F_b$) and the required brace cross sectional sizes of the actual values obtained from shake table tests and NLTHA. In other words, when comparing the ratio of $F_b$ estimated from the DDBD to the measured values in shake table tests, the mean and coefficient of variation ($C_V$) are found to be 1.09 and 0.12, respectively. Moreover, the mean and $C_V$ of the ratios of $F_b$ estimated from the DDBD to the values obtained from NLTHA are found to be 1.03 and 0.12, respectively. Thus, the DDBD methodology presented in this paper has been shown to give accurate and reliable results.

• Geomechanics and Engineering
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• 제11권2호
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• pp.309-323
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• 2016

As the forefront of structural design method, capacity spectrum method can be applied conveniently, and through this method, deformation demand of structure can be considered. However, there is no research for the seismic application in the structure of sheet pile retaining wall to report. Therefore, focusing on laterally loaded stabilizing sheet pile wall, which belongs to flexible cantilever retaining structure and meets the applying requirement of capacity spectrum method from seismic design of building structure, this paper studied an approach of seismic design of sheet pile wall based on capacity spectrum method. In the procedure, the interaction between soil and structure was simplified, and through Pushover analysis, seismic fortification standard was well associated with performance of retaining structure. In addition, by comparing the result of nonlinear time history analysis, it suggests that this approach is applicable.

• 가정과삶의질연구
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• 제28권5호
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• pp.167-181
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• 2010

This research was designed to explore the meaning of housing among Korean Chinese in Harbin, China. In particular, the meaning of housing was examined by using the pathway approach. Utilizing qualitative research methods, this study administered the in-depth interview on the oral history of an individual life, and the 5 elderly persons in their 60s and 70s participated in the individualized interviews that were conducted from May 28 to 31 in 2010. The main findings of meaning of housing were as follows; 1. Similarly to the meaning of housing in 1970s and 1980s in Korea, house was viewed as both a shelter for family members and relatives and a place for their comfort. 2. Prior to multi-story residences, Harbin had only 3 different forms of single-story houses available; Chinese style with Kang and soil room(地室), Korean style with 'Ondol', and Russian style with open floor and Pechka, The promotion at work enabled participants to move to multi-story residences, their moving time varied from 1970 to 1991, and the residential moving determined their current housing status. 3. Multi-story residences were available around 1970s, floor-heating system was introduced from 1990s, and high-rise apartments were built from 1998. Korean Chinese(朝鮮族) weren't satisfied with the spatial composition of individual units embedded into the Chinese culture, especially, entrance, kitchen, bathroom and veranda. 4. Based on assimilation through socialism, adaptation to socialist society and capitalist acculturation, the lifestyles of the interviewees were categorized into five types - capitalist-proactive(Ms. KS), socialist-pragmatic(Ms. J), socialist-inducive(Ms. KY), family centered-conservative(Ms. L), and socialist-adaptive(Ms. P). This study implies that housing-related services for Korean Chinese are necessarily provided so as to embrace their life style and cultural identity in housing design, and further studies need to be explored.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.968-980
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• 2023

The dynamic structural responses are sensitive to the time-frequency content of seismic waves, and seismic input motions in time-history analysis are usually required to be compatible with design response spectra according to nuclear codes. In order to generate spectra-compatible input motions while maintaining the intrinsic non-stationarity of seismic waves, an improved time-domain approach is proposed in this paper. To maintain the nonstationary characteristics of the given seismic waves, a new time-frequency envelope function is constructed using the Hilbert amplitude spectrum. Based on the intrinsic mode functions (IMFs) obtained from given seismic waves through variational mode decomposition, a new corrective time history is constructed to locally modify the given seismic waves. The proposed corrective time history and time-frequency envelope function are unique for each earthquake records as they are extracted from the given seismic waves. In addition, a dimension reduction iterative technique is presented herein to simultaneously superimpose corrective time histories of all the damping ratios at a specific frequency in the time domain according to optimal weights, which are found by the genetic algorithm (GA). Examples are presented to show the capability of the proposed approach in generating spectra-compatible time histories, especially in maintaining the nonstationary characteristics of seismic records. And numerical results reveal that the modified time histories generated by the proposed method can obtain similar dynamic behaviors of AP1000 nuclear power plant with the natural seismic records. Thus, the proposed method can be efficiently used in the design practices.

• 가정과삶의질연구
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• 제27권2호
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• pp.155-171
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• 2009

This study was designed to examine the use of housing in modern Korea, and to draw the interrelation of people and housing. In-depth interviews were conducted, and the qualitative research investigated various aspects of housing history among four individuals during the different phases of social and economic transitions. 4 narratives showed the unique characteristics of life history, and the findings indicated that the housing experiences were closely related to hometown, the relation to birth family at postmarriage, economic status, and the meaning of home. The main findings were as follows: the validity to select the interviewers was proved in that the selection was based on both housing structure type and ownership, and also the research indicated that economic status and housing structure type influenced the entire housing experience of each interviewee. The use of housing varied and the implications of housing lied in social and economic contexts. The use of housing, of which the term was contrived to alternatively described housing consumption modes, and chronology were affected by such individual factors as economic status, familiar relationships, residential location, the meaning and subjectivity of housing.

• 한국지진공학회논문집
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• 제17권2호
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• pp.89-95
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• 2013

Structures in a nuclear power system are designed to be elastic even under an earthquake excitation. However a structural component such as an isolator shows inelastic behavior inherently. For the seismic assessment of nonlinear structures, response history analysis should be performed. In this study, the response of base isolation system was analyzed by response history analysis for the seismic performance assessment. Firstly, several seismic assessment criteria for a nuclear power plant structure were reviewed for the nonlinear response history analysis. Based on these criteria, the spectrum matched ground motion generation method modifying a seed earthquake ground motion time history was adjusted. Using these spectrum matched accelerograms, the distribution of displacement responses of the simplified base isolation system was evaluated. The resulting seismic responses excited by the modified ground motion time histories and the synthesized time history generated by stochastic approach were compared. And the response analysis of the base isolation system considering the different intensities in each orthogonal direction was performed.

• Earthquakes and Structures
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• 제9권4호
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• pp.789-830
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• 2015

The recent re-assessment of the seismic hazard in Europe led for many regions of low to moderate seismicity to an increase in the seismic demand. As a consequence, several modern unreinforced masonry (URM) buildings, constructed with reinforced concrete (RC) slabs that provide an efficient rigid diaphragm action, no longer satisfy the seismic design check and have been retrofitted by adding or replacing URM walls with RC walls. Of late, also several new construction projects have been conceived directly as buildings with both RC and URM walls. Despite the widespread use of such construction technique, very little is known about the seismic behaviour of mixed RC-URM wall structures and codes do not provide adequate support to designers. The aim of the paper is therefore to propose a displacement-based design methodology for the design of mixed RC-URM edifices and the retrofit of URM buildings by replacing or adding selected URM walls with RC ones. The article describes also two tools developed for estimating important quantities relevant for the displacement-based design of structures with both RC and URM walls. The tools are (i) a mechanical model based on the shear-flexure interaction between URM and RC walls and (ii) an elastic model for estimating the contribution of the RC slabs to the overturning moment capacity of the system. In the last part of the article the proposed design method is verified through nonlinear dynamic analyses of several case studies. These results show that the proposed design approach has the ability of controlling the displacement profile of the designed structures, avoiding concentration of deformations in one single storey, a typical feature of URM wall structures.