• Journal of the Korea Institute of Building Construction
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• v.3 no.1
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• pp.85-91
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• 2003

This study aims to provide basic data that can be applied to construct real structures. For this, an experimental structure was manufactured to identify durability according to age of fiber-reinforced concrete which contains fiber reinforcement materials (polypropylene fiber, steel fiber, cellulose fiber) and structural property about flexural behavior and destruction of reinforced concrete beam, and a relation between load and deflection, crack and destruction according to increase of load and ductility capacity was examined. Fiber-reinforced concrete materials and other constructional materials were experimented and the result is presented as follows: The results obtained through material test of concrete and static experiment of members usings 1. The experiment shows that compressive strength of fiber-reinforced concrete was lower than that of non-reinforced concrete. 2. As a result of strength experiment according to different kinds of fiber, compressive strength of an experimented structure that contains cellulose fiber was the highest when age was 28. 3. When deflection of reinforced concrete beam was examined, it was reported that ductility capacity of the experimented structure that contains fiber-reinforced concrete was raise than that of non-reinforced concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.197-198
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• 2023

This study was conducted as part of research and development of high-strength grout. Accordingly, dolomite aggregate was used as a filler incorporated into the high-strength grout. Dolomite aggregate has a disadvantage of increasing the viscosity of the grout due to higher generation of fine powder than other aggregates. Accordingly, in this experiment, it was confirmed that the viscosity, flow time, and flow of high-strength grout change according to the volume composition ratio of dolomite aggregate and cement-based material. All experiments were conducted based on the Korean Industrial Standard KS F 4044, and the mixing factor was applied according to the composition ratio of the binder and the filler. In the experiment, the amount of fine powder contained in the dolomite aggregate rather than the silica sand used in the past is grasped, and after mixing with the grout accordingly, the mixture is proceeded to measure the viscosity in an unhardened state. In addition, the flow and flow time of the grout are evaluated according to the viscosity. As a result of the experiment, it was confirmed that the viscosity and flow time decreased and the flow increased as the volume composition ratio of the dolomite aggregate to the cement-based material increased.

• Journal of Urban Science
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• v.11 no.2
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• pp.25-30
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• 2022

Resin Transfer Molding FRP (RTM FRP) is a fiber reinforced polymeric plastic which is manufactured by applying pressure to fibers, injecting resin into a mold, and then impregnating it. RTM FRP is a new construction material suitable for producing non-continuum structural elements such as sole plate because it has excellent strength and can produce many members in a short time. In this study, experiments were conducted to estimate the capacity of the bolted connection of RTM FRP. First, a tensile test was conducted to confirm the mechanical properties such as the tensile strength of the RTM FRP to be used for the bolted connection experiments. In addition, experiments were conducted on the bolted connection with the thickness of the RTM FRP and the edge distance of the bolt as variables. In the first experiment, F4.8 bolts were used, and shear failure of the bolt occurred before the RTM FRPs were failed. The F4.8 bolt is a general structural bolts used for the sole plate of a bridge bearing, and it was confirmed that the RTM FRP has a higher bold bearing strength than the shear strength of a F4.8 bolt. In the second experiment, G12.9 bolts were used, and shear failure of the bolt and bearing failure of the RTM FRP occurred simultaneously. In addition, as the thickness of the RTM FRP and the edge length of the bolt increased, the strength of the joint increased. When analogized with the bearing fracture equation of steel plate, the bolted connection of RTM FRP showed a bearing strength coefficient of 0.420 to 0.549 compared to the tensile strength, and it is considered that further research is needed.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.4
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• pp.15-27
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• 2018

Purpose : This study aims to present a rehabilitation exercise and physical education program (REPEP) for local community stroke patients by examining an exercise program provided from traditional physical therapeutic perspectives. Methods : The subjects were 40 stroke patients residing in a local community and managed by a public health center (the group-exercise group: 20, the individual-exercise group: 20). In the case of the group-exercise group (GEG), the subjects were divided into small groups composed of five members each to participate in the program. The individual-exercise group (IEG) took part in the program individually. The subjects received a REPEP that included a warm-up exercise, an elastic band exercise, a leg exercise, a balance and gait exercise, an arm and trunk exercise, and a cool-down exercise twice per week for 20 weeks. They had their gait function, balance index, and muscle strength in the bilateral knee joints tested before and after the experiment. Results : Compared to before the experiment, both groups' gait function, balance index, and muscle strength in the knee joints increased after the experiment. After the experiment, the GEG experienced more improvement in their gait function, balance index, and muscle strength in the bilateral knee joints, excluding their gait velocity and $300^{\circ}/sec$ flexion and extension, than the IEG (p<.05). Conclusion : An exercise program provided from the traditional physical therapeutic perspectives may be applied to stroke patients as their REPEP. In addition, a REPEP was more effective in improving their gait function, balance index, and muscle strength in the knee joints when the subjects formed a group and took part in the program than when they partook in it individually.

• Journal of Korean Society of Steel Construction
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• v.10 no.2 s.35
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• pp.161-175
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• 1998

The objective of this study is to investigate the structural behavior of Concrete-Filled Steel Tubular Column-H Beam connections with plate stiffeners. The first, we made experiment on the Column to H-beam flange connections stiffened with simple tensile loading. The paramaters of tensile experiment are the area of each plates. The simple tensile experiment is conducted to 5 kinds of specimens. Eestimating the load, displacement, and strain from each kind, we compared them with results of second experiment. The second, we made experiment on the Column to H-beam connections stiffened with the sames under monotonic and cyclic load. we made specimens of 5 for the second experiment. In analysis, comparing each strengthes and stiffnesses we estimated deformation capacity. Comparing and estimating each yielding strength ratios and maxium-strength ratios on the basis of Yield line theory, we suggested new Strength Formula of Beam-to-Column Connections.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.103-104
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• 2015

This study is an experiment about what affects the compressive strength by using a reducing agent (PNS based admixtures) to play cement using the cement paste based Waste Concrete Powder of waste concrete, which accounts for more than 60% of construction waste around the latest domestic and international It was. Securing the replacement of cement with Waste Concrete Powder and, by varying the admixture was to compensate for the low absorption of liquidity and obtain a fine powder. And the experiment was conducted with a constant water cement ratio and aggregate usage for the purpose of lowering the water cement ratio promoting strength development. When substituted with the experimental results of 0.3% based on 3 ~ 28 days as strength 36Mpa exhibited the highest strength.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1057-1062
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• 2000

The purpose of this study is to practice the method which can estimate 28-days strength of concrete in advance. This method is made for reliant quality control. Based on existing experiment, concrete that flyash added and normal concrete are placed into wall structure, and it is examined the difference between experiment use concrete and field use concrete. The result of this study are as follows : 1) Core test specimen have 10% lower strength to standard curing specimen. 2) At 28-days accelerated strength by microwave, average 35% in normal concrete, average 23% in flyash added concrete. 3) At coefficient of determination between compressive strength and accelerated strength, 0.84 in normal concrete core, 0.86 in standard curing normal concrete, 0.86 in flyash added concrete, 0.90 in standard curing flyash added concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.113-114
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• 2014

Though polymer cement mortar is widely used to repair or reinforce concrete as it has superior adhesion, dense internal structure, chemical resistance, and workability in comparison to those of general cement mortar, studies on its behaviors in high temperature environment such as fire is urgently required. Accordingly, in this experiment, the degrees of reduction in the compressive strength at different temperatures was grasped applying ISO834 Heating Curve, and the effect of polymer content and type on compressive strength could be determined. As a result of this experiment, it is found that polymer type and content have a big effect on reduction of compressive strength in high temperature range, and not only the dynamic characteristics but also the combustion characteristics in high temperature range are required to be studied considering occurrence of a fire in the future.

• Journal of Korean Academy of Nursing
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• v.26 no.3
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• pp.556-575
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• 1996

In an attempt to investigate the effect of a muscle strengthening exercise program on muscle strength, pain, depression, self-efficacy and quality of life of patients with knee osteoarthritis, a pre-experiment, one group pre-test & post-test design, was planned. Muscle strengthening exercise was carried out from May 22 through August 14, 1995 at isokinetic exercise room in rehabilitation department of University Hospital in Taejon. The subjects were seven female clients conveniently sampled from University Hospital located in Taejon, between 39 and 61 years of age, who had a osteoarthritis in knee. Muscle strengthening exercise program was composed of three sessions per week, one isokinetic exercise at angular velocity of 60° and 180° with Cybex isokinetic dynamometer and two resistance home exercise sessions with elastic band. Data were analyzed with frequency, percentage of change, Friedman test, Duncan test using SAS program. Results were obtained as follows : 1) Flexion and extension muscle strength at angular velocity of 60° and 180° were increased after 12weeks' exercise than those of before experiment. But exept flexion muscle strength at angular velocity of 180°(F=3.34, P=0.0261), there was no statistically significant difference among muscle strengths, which is measured every 3 weeks. 2) Pain was decreased after 6weeks' exercise than that of before experiment, and after 12weeks' exercise than that of 6weeks' exercise. There was statistically significant difference (F=4.28, P=0.0396). 3) Depression was increased after 6weeks' exercise than that of before experiment, and after 12weeks' execise than that of 6weeks' exercise. There was no statistically significant difference between before experiment and after 6weeks' exercise. But, there was statistically significant difference between after 6weeks' exercise and 12weeks' exercise(F=9.38, P=0.0035). 4) Self-efficacy was decreased after 6weeks' exercise than that of before exercise. But, it was increased after 12weeks' exercise than that of be-fore exercise and after 6weeks' exercise. But there was no statistically significant difference (F=1.46, P=0.2706). 5) Quality of life was increased after 6weeks' exercise than that of before exercise, and after 6weeks' exercise than that of 12weeks' exercise. But there was no statistically significant differ once (F=1.06, P=0.3816). Thus, the significant of muscle strengthening exercise for the improvement of muscle strength, pain, depression, is verified. But, this study was a pre-experiment with small size subjects. So, con-trolled experimental study is necessary to determine the effect of this muscle strengthening exercise program on muscle strength, pain, depression, self-efficacy, and quality of life of patients with knee osteoarthritis.

• Structural Engineering and Mechanics
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• v.40 no.2
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• pp.215-231
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• 2011

The axial compressive strength of unidirectional FRP is generally quite lower than its axial tensile strength. This fact decreases the advantages of FRP as main load bearing member in engineering structure. In order to restrain the lateral expansion and splitting of GFRP, and accordingly heighten its axial compressive bearing capacity, a project that to confine GFRP pole with surrounding CFRP sheet is suggested in the present study. The Experiment on the CFRP sheet confined GFRP poles showed that a combined structure of high bearing capacity was attained. Basing on the experiment research a theoretical iterative calculation approach is suggested to predict the ultimate axial compressive stress of the combined structure, and the predicted results agree well with the experimental results. Then the influences of geometrical parameters on the ultimate axial compressive stress of the combined structure are also analyzed basing on this approach.