• Journal of Korean Association for Spatial Structures
• /
• v.7 no.3 s.25
• /
• pp.141-151
• /
• 2007

The appearance of many Glass Fiber Reinforced Plastic (GFRP) constructions look like ordinary steel construction, because GFRP has been imitated by the same way with the traditional steel's cross section as well as connection system. In terms of detachable connection, there was not enough appropriate option of GFRP connection, such as a traditional bolt connection for steel and wood structures. Most of all, from material characteristic of GFRP related to the deficient ductility, the shearstress principle of GFRP s not proper for the material property, which causes ineffective and not economic application of material. With this research problem, the innovative and detachable onnection system, which is more considered with appropriate material characteristic for FRP, is developed. Not only short time but also long time research with various connection variations is carried out.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2008.04a
• /
• pp.50-55
• /
• 2008

In order to investigate and estimate the cause of fatigue crack occurred to curved girder bridge that is used during 20 years, in this study, filed tests to obtain the characteristic of stress hysteresis were performed under the real traffic flows. From these test results, we analyzed the cause of fatigue crack for various fatigue crack patterns. Also, the characteristic of structural behavior for the curved girder bridge were examined from the FE analysis. In addition, to retrofit various fatigue cracks occurred in the bridge, FE analyses considering the characteristics of crack patterns were performed and retrofitting methods were suggested.

• Research in Mathematical Education
• /
• v.7 no.4
• /
• pp.247-270
• /
• 2003

The purpose of this study is to build a model that explains the relationship between and among five variables that are student background, teacher background, home environment, school characteristic, and student mathematics achievement, using structural equation modeling. Another purpose of this study is to compare the relationships of these variables between the United States and Korea in 7th and 8th grades mathematics. Student, teacher, and school background files from population 2 in the TIMSS were selected for this study. The result of the study provides practical information for teachers, parents, school principals, and other people who are interested in improving student achievement, and also provides the information that may explain differences and similarities between the US and Korea in mathematics achievement.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1992.04a
• /
• pp.118-125
• /
• 1992

The ground deformation due to the tunnel excavation is dependent on various factors such as ground condition, geometry of the tunnel, excavation method, installation of support members, construction condition of each excavation stage, etc. And the distance from the facing effects significantly the stress conditions of the supported and unsupported ground due to the 3-dimensional structural nature of the excavated tunnel. The concept of ground characteristic line has been applied to properly consider the loading condition given by staged tunnel excavation so that the imaginary supporting pressure is applied against the surface of excavated ground. Discussions on the results of the performed finite element analysis were mainly made with respect to the ground settlement, tunnel displacement, earth pressure, stress mobilized in supporting members.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.2
• /
• pp.172-179
• /
• 2005

A high-precision centerless grinding machine has been recognized as a core equipment performing the finish outer-diameter grinding process of ferrules which are widely used as fiber optic connectors. In this study, in order to realize the high-precision centerless grinding machine, the structural characteristic analysis and evaluation are carried out on the virtual prototype consisted of the steel bed, hydrostatic GW and RW spindle systems, hydrostatic RW feed mechanism, RW swivel mechanism, and on-machine GW and RW dressers. The loop stiffnesses of centerless grinding machine are estimated based on the relative deformations between GW and RW caused by the grinding forces. And the simulated results illustrate that the concrete-filled bed has the considerable effect on the improvement of the structural stiffness of centerless grinding machine.

• International Journal of Precision Engineering and Manufacturing
• /
• v.7 no.4
• /
• pp.34-39
• /
• 2006

High-precision centerless grinding machines are emerging as a means of finishing the outer diameter grinding process required for ferrules, which are widely used as fiber optic connectors. In this study, a structural characteristic analysis and evaluation were carried out using a virtual prototype of a centerless grinding machine to realize systematic design technology and performance improvements required to manufacture ferrules. The prototype consisted of a concrete-filled bed, hydrostatic grinding wheel (GW) and regulating wheel (RW) spindle systems, a hydrostatic RW feed mechanism, a RW swivel mechanism, and on-machine GW and RW dressers. The loop stiffness values of the centerless grinding machine were estimated based on the relative displacements between the GW and RW caused by grinding forces. The simulated results illustrated that a concrete-filled bed considerably improved the structural stiffness and accuracy of a high-precision centerless grinding machine.

• Proceedings of the KSR Conference
• /
• 2004.10a
• /
• pp.680-685
• /
• 2004

The effects of acid rain and salt content on corrosion behavior were investigated with rolling stock structural steels be caused by environmental. Since these materials are exposed to the corrosive environments like polluted air, acid rain and sea water, it is important to investigate corrosion behaviour in various corrosive environments. The aqueous corrosion of the characteristic materials in aerated acid rain and neutral solution were studied by using immersion tests, electrochemical measurements and analytical techniques. In order to examine corrosion characteristic, structural steels were electrochemically evaluated with respect to the dissolved oxygen content, pH, chloride ion concentration.

• Structural Engineering and Mechanics
• /
• v.13 no.2
• /
• pp.231-239
• /
• 2002

The problem of dynamic analysis of truss structures based on probability is studied in this paper. Considering the randomness of both physical parameters (elastic module and mass density) of structural materials and geometric dimension of bars respectively or simultaneously, the stiffness and mass matrixes of the elements and structure have been built. The structure dynamic characteristic based on probability is analyzed, and the expressions of numeral characteristics of inherence frequency random variable are derived from the Rayleigh's quotient. The method of structural dynamic analysis based on probability is developed. Finally, two examples are given.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2004.10a
• /
• pp.331-338
• /
• 2004

In this paper, stiffness and damping matrices are experimentally constructed using structural modal information on frequencies, damping ratios and modal vectors, which are obtained by shaking table tests. The acceleration of the shaking table is used as the input signal, and the resulting acceleration of each floor is measured as output signal. The characteristic and limitation of modal information from shaking table test are obtained by Common Based-normalized System Identification(CBSI) technique which is based on time domain information.

• Journal of the Korean Home Economics Association
• /
• v.49 no.1
• /
• pp.121-133
• /
• 2011

This research was designed to compare the subjective evaluation of texture image and preference between offline and online by structural characteristics of women' jacket fabrics for spring and summer. 78 participants evaluated the sensibility image and preference of various fabrics. The data were analysed by factor analysis, t-test, Pearson's productive correlation, regression, and multi dimensional scale. The results were as follows: Sensibility image factors of women' jacket fabrics were 'classic' 'sophisticated' 'natural' 'characteristic' and 'practical'. Between offline and online, sensibility images showed no differences. In sensibility images, 'classic'-'sophisticated', 'natural'-'practical', and 'practical'-'characteristic' images showed significant correlation. By analyzing the contribution of fabric structure on sensibility images, density affected on the 'classic' image offline and online. By the results of regression analysis, thickness, density and weave affected on the tactile preference. In sensibility images, 'classic', 'sophisticated' 'characteristic' images were the influencing factor. 'Sophisticated', 'natural', 'characteristic' and 'practical' images affected on the purchase preference.