• Journal of Korean Association for Spatial Structures
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• v.9 no.4
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• pp.18-22
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• 2009

• Journal of Korean Association for Spatial Structures
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• v.10 no.2
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• pp.21-24
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• 2010

• Journal of Korean Association for Spatial Structures
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• v.13 no.2
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• pp.18-24
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• 2013

• Journal of Korean Association for Spatial Structures
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• v.2 no.1 s.3
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• pp.41-49
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• 2002

In this paper, a study of 2-step damage detection for space truss structures using the extended Kalman filter theory is presented. Space truss structures are composed of many members, so it is difficult to find damaged member from the whole system. Therefore, 2-step damage identification method is applied to detect the damaged members. First, kinetic energy change ratio is used to find damage region including damaged member and then detect damaged member using extended Kalman filtering algorithm in damage region. The effectiveness of proposed method is verified through the numerical examples.

• International Journal of Aeronautical and Space Sciences
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• v.11 no.4
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• pp.266-284
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• 2010

Piezoelectric materials have become the most attractive functional materials for sensors and actuators in smart structures because they can directly convert mechanical energy to electrical energy and vise versa. They have excellent electromechanical coupling characteristics and excellent frequency response. In this article, the research activities and achievements on the applications of piezoelectric materials in smart structures in China, including vibration control, noise control, energy harvesting, structural health monitoring, and hysteresis control, are introduced. Special attention is given to the introduction of semi-active vibration suppression based on a synchronized switching technique and piezoelectric fibers with metal cores for health monitoring. Such mechanisms are relatively new and possess great potential for future applications in aerospace engineering.

• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.123-127
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• 2010

A fire disaster is very serious in the closing space like subway station. In this study, the simulation on fire diffusion is performed to get the temperature history curve, which is used for the fire resisting structural analysis. Most of subway stations are built by the reinforced concrete structure, but recently steel structures are selected for the larger space or beauty. Steel structures relatively have more weaknesses against fire, so it is necessary to develop the method for evaluating fire-resisting capacity in this kind of structures. The developed method is applied to the subway station in Daegu city. It shows that the developed method can be used to simulate the fire disaster and to get the temperature history curve and evaluate the safety of steel structures against the fire.

• Korean Institute of Interior Design Journal
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• v.14 no.3 s.50
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• pp.181-190
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• 2005

In accordance with the rapid growth of digital media in 1990s, the state of indetermination that is found in digital process has been emphasized in the field of natural science and philosophy. Digitalized space design has been dramatically developed and it raised heated debate and comment on 'folded space' The purpose of this thesis is to explore how the cognitive-ecological factors constitute fold structures in space design of the late 20th century. Syntax of space structure and geometric composition were analyzed to define what types of cognitive-ecological factors are contrived in the process of visual information. In particular, I put higher theoretical emphasis on what characteristics are ensued in the process of structuring spaces than any other subjects. Through theses analyses and discussions, I raised questions on what principles are operating to create new space design that counts on non-linear structure and its formational process. And I also observed what influences these structural principles of design could fundamentally bring to human beings. First, I proposed that we could overcome reductionist space design through cognitive-ecological approach. Some key concepts such as affordance, parallel processing, and redundancy were adopted as defining elements of non-linear structures. As a result of analyses, I found that the cognitive-ecological approach could substitute the reductionist space design of the past. What is also found is that the three variables are the ultimate ecological elements. In addition, as a methodological concept of fold structures, the form of 'topology' was highlighted because it could be a supporting idea to the cognitive-ecological factors. Second, I claimed that non-linear design is more experiential than rational linear design, and it is more efficiently correspondent to human being than any other forms. What is intended and implied in non-linear structure is also indicated.

• Structural Engineering and Mechanics
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• v.90 no.6
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• pp.543-549
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• 2024

The utilization of the fabric materials for lightweight building structures has attracted considerable attention due to the multiple functions and high strength-to-weight ratio. The mechanical properties of the fabric materials evolve with the loading cycle, especially for the Poisson's ratio that requires the full cyclic strain to determine the accurate values. The digital image correlation method has been justified but needs to meet the flexibility and complexity requirements of the fabric materials. This paper thus proposes a modified digital image correlation method to quantify the Poisson's ratio of fabric materials. To obtain the accurate Poisson's ratio of fabric materials in the cyclic experiments using non-contact measuring method, a speckle generation of the digital image correlation method is implemented to obtain the strain distribution and strain characteristics. The uniaxial cyclic experiments for the fabric materials are carried out in the warp, weft and 45° directions. The digital image correlation photos are taken when the material properties become stable in the cyclic loading. The results show that the strain distributions are non-uniform and dependent on the specimen directions. The reliable Poisson's ratios of the fabric materials in the warp, weft and 45° directions are 0.016, 1.2 and 2.6. The strain asymmetry at the maximum strain position is related with the weaving architecture. These observations and results are indispensable to understand the Poisson's ratios of fabric materials and to guide the proper analysis of the large-span membrane structures.

• Journal of the Korean Mathematical Society
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• v.33 no.3
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• pp.625-639
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• 1996

A convex $RP^n$-structure on a smooth anifold M is a representation of M as a quotient of a convex domain $\Omega \subset RP^n$ by a discrete group $\Gamma$ of collineations of $RP^n$ acting properly on $\Omega$. When M is a closed surface of genus g > 1, then the equivalence classes of such structures form a moduli space $B(M)$ homeomorphic to an open cell of dimension 16(g-1) (Goldman [2]). This cell contains the Teichmuller space $T(M)$ of M and it is of interest to know what of the rich geometric structure extends to $B(M)$. In [3], a symplectic structure on $B(M)$ is defined, which extends the symplectic structure on $T(M)$ defined by the Weil-Petersson Kahler form.

• Journal of Ocean Engineering and Technology
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• v.5 no.2
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• pp.16-30
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• 1991

A numerical procedure is described for predicting the dynamic responses of combined systems of floating breakwaters and huge offshore structures supported by a large numer of the floating bodies in waves. The hydrodynamic interactins among tatal floating bodies are taken into account in their exact form within the context of linear potential theory. Wave control effects are discussed with both hydrodynamic interactions and hydrodynamic-structure interaction effects. The method presented is applicalbe to combined systems of floating breakwaters and huge structures for ocean space utilization for which a number of practical uses are seen in the future.