• Journal of Korean Association for Spatial Structures
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• v.6 no.1 s.19
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• pp.55-63
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• 2006

Concrete-filled steel columns consist of circular, square or rectangular hollow sections filled concrete. Much research has studied for the behavior of concrete-filled steel structures. The advantages from structural point of view are the triaxial confinement of the concrete within the section, and the fire resistance of the column which largely depends on the residual capacity of the concrete core. The axial capacity of a concrete-filled rectangular or circular section is enhanced by the confining effect of the steel section on the concrete which depends in the magnitude on the shape of the section and the length of the column. Buckling tends to reduce the benefit of confinement on the squash load as the column slenderness increases. In circular sections it is possible to develop the cylinder strength of the concrete. When compare with reinforced concrete columns, the concrete-filled composite column possesses much better strength and ductility in shear and generally in flexure also. Many researches are being conducted about concrete filled steel column to get these advantages in building design. In this paper it is provided to the basic experimental study of compression behavior of the circular and rectangular tubular steel pipe filled with concrete.

• Physical Therapy Korea
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• v.20 no.3
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• pp.81-88
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• 2013

Active straight-leg raise (ASLR) is a physical evaluation procedure to test lumbar spine stability. Several previous studies have reported various methods to control the activation of abdominal muscles during ASLR. We investigated the effects of three different hip positions in frontal plane on abdominal muscles to increase or decrease the difficulty level of lumbar spine stability exercise during ASLR in pain free subjects. Eleven young and healthy subjects voluntarily participated in this study (6 men, 5 women; mean age=$24.0{\pm}1.2$ years, height=$160.0{\pm}7.3cm$, weight=$55.0{\pm}10.6kg$, body mass index=$21.5{\pm}2.3kg/m^2$). The subjects had three trials on each ASLR with hip $10^{\circ}$ adduction, neutral hip, and hip $30^{\circ}$ abduction. Separate repeated-measures analysis of variance (ANOVA) and the post hoc Bonferroni tests (with ${\alpha}$=.05/3=.017) were performed for each muscle among the three different hip positions in frontal plane (ASLR with hip $10^{\circ}$ adduction, neutral hip, and hip $30^{\circ}$ abduction). The ipsilateral external oblique (EO), contralateral EO, ipsilateral internal oblique/transverse abdominis (IO/TrA), and contralateral IO/TrA were significantly greater in ASLR with hip $30^{\circ}$ abduction compared with ASLR with hip $10^{\circ}$ adduction. Also, the ipsilateral EO, contralateral EO, and ipsilateral IO/TrA were significantly greater in ASLR with hip $30^{\circ}$ abduction compared with ASLR with neutral hip. These results suggest that ASLR with hip $30^{\circ}$ abduction and neutral would be useful method to strengthen the EO and IO/TrA. And, ASLR with hip $10^{\circ}$ adduction would be effective in early stages of lumbar stabilization program due to low activation of EO and IO/TrA during maintaining of ASLR position with low load.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.2
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• pp.41-49
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• 1993

This paper presents a geometrically non-linear and elastoplastic F.E. formulation using a total Lagrangian approach for the two dimensional isoparametric curved beam elements. The beam element is derived by using plane stress elements. The basic element geometry is constructed using the coordinates of the nodes on the element center line and the nodal point normals. The element displacement field is described using two translations of the node on the center line and a rotation about the axes normal to the plane containing the center line of the element. The layered approach is used for the elastoplastic analysis of the plane framed structure with the arbitrary cross section. The iterative load or displacement incremental method for non-linear finite element analysis of the frame structure is used. Numerical examples are presented to demonstrate the behavior and the accuracy of the proposed beam element for geometric and elastoplastic non-linear applications. Comparisons made with present theory and other published data show that tilt' beam element products accurate results with good convergence characteristics.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.3 s.174
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• pp.613-624
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• 2000

In this study, new design method of prosthetic foot was suggested which can evaluate the performance of prosthetic foot by implementing amputee's gait simulation using the finite element analysis. The basic shape of ESPF(Energy Storing Prosthetic Foot) was designed which is suitable for the below-knee amputee considering mechanical properties and kinematic properties. And, the performance evaluations were performed using the Taguchi method with orthogonal array L25. As a result, average main effect of factors for the ESPF's performance were calculated and then optimum condition of given shape was selected. Essential particulars for the performance evaluation from the simulation result were the quantity of external work needed in stance phase, the quantity of transferred energy from the ESPF through the knee, and the vertical displacement of knee at toe-off. Reasonable optimum condition was obtained from the using performance index. From this study, it was found that it is necessary for the design of ESPF to consider the geometrical data related to the magnitude of load on elastic material.

• Computational Structural Engineering
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• v.4 no.3
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• pp.89-97
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• 1991

Conventional aseismic design methods of R/C frame all but disregard the state of damage over the entire building frame. This paper presents an automated damage-controlled design method for R/C frames which aims at an uniform energy dissipation rate throughout the building frame, so that the resulting damage is uniformly distributed as much as possible over all element. The accuracy of the basic hystertic model and the damage model for R/C members is verified by reproducing the experimental load-deformation curves of one-bay one-story frames. Application of this design method to various frame structures indicate that 1) regardless of the structural properties or input earthquake characteristics, damage-controlled frames generally survive more severe earthquake excitations and suffer less damage than conventionally designed frames, and 2) member yielding strength in the lower stories of damage-controlled frames is larger than that for conventionally designed frames, while the trend is opposite in the upper stories.

• Journal of the Korea Society of Computer and Information
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• v.16 no.10
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• pp.53-62
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• 2011

In this paper, high-tech IT Convergence, to the development of complex technology, special technology, video object recognition technology was considered only as a smart - phone technology with the development of personal portable terminal has been developed crossroads. Technology-based detection of 3D face recognition technology that recognizes objects detected through the intelligent video recognition technology has been evolving technologies based on image recognition, face detection technology with through the development speed is booming. In this paper, based on human face recognition technology to detect the object recognition image processing technology is applied through the face recognition technology applied to the IP camera is the party of the mouth, and allowed the ability to identify and apply the human face recognition, measurement techniques applied research is suggested. Study plan: 1) face model based face tracking technology was developed and applied 2) algorithm developed by PC-based measurement of human perception through the CPU load in the face value of their basic parameters can be tracked, and 3) bilateral distance and the angle of gaze can be tracked in real time, proved effective.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.4
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• pp.27-40
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• 2013

These day morden cities have serious climatic problems due to enviornmental load caused by excessive development of urbanization. As technological improvement to answer to various ecological disasters and climate changes are also called on the field of construction, inter-disciplinary studies linked to the estabilishment of sustainable energy generation systems and enviornmental control is needed in a consilient point of view. This study aims to analyse optimal site conditions for photovoltaic system and green roof planting through solar radiation simulation in a integrated perspective. In so doing, it seeks to proffer basic study for developing a sound use of roof area that is sustainable in environmental and resources aspects. A computer simulation showed that, in the case of total seasonal solar radiation, summer season resulted 312.5kWh in 35% of total annual solar radiation. This season indicated the lowest radiation rate of the year for direct sunlight in 45.8% of total seasonal solar radiation. Due to such solar radiation simulation, at the largest optimal planting area, Glechoma hederacea var. longituba secured $719.16m^2$ of gross roof area.

• Journal of Korean Society on Water Environment
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• v.22 no.4
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• pp.695-705
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• 2006

This study was carried out to make a basic information for establishment of countermeasures against water pollution of Hoengseong watershed, accordingly we investigated the characteristics of pollutants discharge and estimated the unit loads from Hoengseong watershed. Seven sites (S1~S7) were selected for sampling and samples were taken 4 times during the dry and rainy seasons, respectively. During rainfall events, measured site mean concentration (SMC) ranges of $BOD_5$, $COD_{Mn}$, TOC, SS, Turbidity, T-N and T-P were 0.8~1.3 mg/L, 2.3~6.3 mg/L, 1.284~2.110 mg/L, 3.4~69.3 mg/L, 2.36~52.68 NTU, 1.243~1.669 mg/L and 0.025~0.070 mg/L, respectively. And the calculated annual unit loads of $BOD_{5}$, $COD_{Mn}$, SS, T-N and T-P in Hoengseong watershed were 1.327 kg/ha/yr, 7.349 kg/ha/yr, 87.075 kg/ha/yr, 1.848 kg/ha/yr and 0.103 kg/ha/yr, respectively. It was difficult to directly compare the unit loads proposed in this study with the estimated existing those. Because the unit loads in this paper were estimated not by land use types, but by complex land use of non-urban area. From the survey results, they showed that the unit loads in Hoengseong watershed were similar to those exisiting in the forest area, and showed lower than those existing in the paddy/dry field.

• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.717-726
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• 2006

Traditional external post-tensioning method using either steel bars or tendons is commonly used as a retrofitting method for steel composite bridges. However, the method has some disadvantages such as stress concentration at anchorages and inefficient load-carrying capability of live loads. Multi-stepwise prestressing method using thermal expanded coverplate is a newly proposed prestressing method, which was originally developed for prestressing steel structures. A new retrofitting method for steel girder bridges founded on a simple concept of thermal expansion and contraction of cover plate, the method is a hybrid of and combines the advantages of external post-tensioning and thermal prestressing. In this paper, basic concepts of the method are presented and an illustrative experiment is introduced. From actual experimental data, the thermal prestressing effect was substantiated and the FEM approach for its analysis was verified. The retrofitting effects ofa single-span bridge were analyzed and the feasibility of the developed method was examined.

• Journal of Korean Society of Steel Construction
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• v.23 no.1
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• pp.73-81
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• 2011

The wind force coefficient of a transmission tower frame shows several characteristics when the section shape, solidity ratio, and wind direction angle are changed. In this study, the wind force characteristics of a transmission tower frame with a basic structure were evaluated using different solidity ratios and wind direction angles in a wind tunnel test. According to the solidity ratio, the size of the structure and the rectangular-frame model of the transmission tower were changed by adding a two-dimensional (2D) or three-dimensional (3D) structure. The transmission tower's rectangular frame was tested by changing the wind direction angle of the 2D-type structure from 0 to $90^{\circ}$ and by changing the wind direction angle of the 3D-type structure from 0 to $45^{\circ}$ Based on the results that were obtained, it can be concluded that the wind force coefficient of a transmission tower frame can be used as preliminary data in deciding the transmission tower's wind load.