• The Journal of Korean Society for School & Community Health Education
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• v.18 no.1
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• pp.81-97
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• 2017

Objecives: This study was performed to analyze the effect of the family strength perceived by college students on flow. Methods: To achieve this purpose, a survey on the family strength and flow was conducted on 113 male college students and 187 female college students. Correlation analysis and independent sample t-test were carried out among the variables, and regression analysis was performed to examine the effect of the family strength on flow. Results: The results are as follows. Firstly, the family strength of the college students had a static correlation with flow. Secondly, the examination on the difference between the male and female college students in the family strength and the flow revealed that the family strength and flow of male students were significantly higher than those of the female students. Thirdly, according to the analysis on the influence of family strength on flow when the sociodemographic background was controlled, the shared value system among family members, the ability of problem solving, and ties with family members from the sub-factors of family strength had significant effect on the sub-factors of flow. Conclusions: Through the above results, this study identified that family strength is important for college students who have greater independence and freedom than in middle and high school, and the higher family strength was, the higher flow was. This result can be used as a basis to prepare a practical intervention plan to increase the flow of college students.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.1
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• pp.121-130
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• 2023

Purpose : This study aimed to investigate the effect of blood flow restriction exercise on ankle muscle strength and balance ability to achieve maximum efficiency with the same exercise intensity and time. Methods : Twenty-six adults are randomly assigned to experimental group (n=13) and comparison group (n=13). The experimental group performed ankle joint strength exercises with blood flow restriction applied while the comparison group performed ankle joint strength exercises without blood flow restriction applied three times a week for four weeks. The digital muscle measurement, Y-balance test, and Cumberland ankle instability tool were used to evaluate the subject's muscle strength, dynamic balance, and ankle instability index before and after the intervention. Results : In within-group comparison muscle strength, all the two groups showed significant improvements post intervention (p<.05). In between-group comparison, there was significant difference in the change of dorsiflexion, eversion strength pre and post intervention (p<.05). but plantarflexion was no significant difference between pre and post intervention in the group comparison (p>.05). In within-group comparison dynamic balance, all the two groups showed significant improvements post intervention (p<.05). In between-group comparison, there was no significant difference in the change of Y-balance score pre and post intervention (p>.05). In within-group comparison ankle instability index, all the two groups showed significant improvements post intervention (p<.05). In between-group comparison, there was no significant difference in the change of CAIT score pre and post intervention (p>.05). Conclusion : The results of this study show that ankle joint strength exercise improved the strength and balance ability of those complaining of chronic ankle instability, and ankle joint strength exercise applied with blood flow restriction was more effective in dorsiflexion and eversion strength exercise than ankle joint strength exercise without blood flow restriction.

• PNF and Movement
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• v.19 no.3
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• pp.441-449
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• 2021

Purpose: The purpose of this study was to investigate the effect of strength training combined with blood flow restriction on leg muscle thickness in children with cerebral palsy. Methods: Nineteen children with cerebral palsy, aged between five and 10 years of age, living in area N, were recruited. Ten participants were classified into a blood flow restriction group and nine into a strength exercise group. The experimental group performed strength training using a blood flow restriction cuff on the leg, and the control group performed strength training without blood flow restriction. A paired t-test was performed to confirm intragroup changes before and after five weeks of the experiment, and an independent t-test was performed to confirm intergroup changes, and the significance level was α=0.05. Results: The rectus femoris, gastrocnemius and gluteus medius muscles showed significant differences in the groups after five weeks (p<0.05). There was a significant difference between the groups in the rectus femoris and gastrocnemius after five weeks (p<0.05). Conclusion: As a result of this study, it was found that strength training combined with blood flow restriction had a positive effect on the changes in leg muscle thickness in children with cerebral palsy. This suggests the possibility of using it in the future as basic data for strength training methods and blood flow restriction exercises for children with cerebral palsy.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.145-152
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• 2004

The flow stress value was calculated by comparing predicted and measured roll force. Using basic on-line roll force model and logged mill data the flow stress equation of high strength steel for automobile was derived. The flow stress equation consists of the flow stress equation of carbon steel and flow stress factor calculated by neural network with input parameters not only carbon contents, strip temperature, strain, and strain rate, but also compositions such as Mn, p, Ti, Nb, and Mo. Using the flow stress equation and basic roll force model, precision roll force model of high strength steel for automobile was derived. Using test set of logged mill data the flow stress equation was verified.

• 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.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.05a
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• pp.69-74
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• 2002

The following results are achieved from a mortar flow test depending on stainless steel slag fineness, replacement ratio, and a research on material age compressive strength, strength activity index. 1. Flow is proportional to the stainless steel slag fineness within the limits of 4000~8000$\textrm{cm}^2$/g, but in the case of fineness 20000$\textrm{cm}^2$/g flow decreases at all conditions except the case of replacement ratio 10%. 2. As stainless steel slag replacement ratio increases, Mortar of flow somewhat decreases. 3. As stainless steel slag blends, compressive strength decreases, but in proportion to the increase of age, compressive strength increases. 4. As stainless steel slag replacement ratio, compressive strength decreases. 5. In the case of stainless steel slag fineness 6000$\textrm{cm}^2$/g and 20.000$\textrm{cm}^2$/g, compressive strength of revelation ratio has the maximum value when it's replacement ratio is 10%.

• Journal of the Korean Geotechnical Society
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• v.29 no.11
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• pp.73-84
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• 2013

When a slope failure or a debris flow occurs, a shear strength on failure plane becomes nearly zero and soil begins to flow like a non-cohesive liquid. A consistency of cohesive soils changes as a water content increases. Even a cohesive soil existing at liquid limit state has a small amount of shear strength. In this study, a water content, at which a shear strength of cohesive soils is zero and then cohesive soils will start to flow, was proposed. Three types of clays (kaolinite, bentonite and kaolinite (50%)+bentonite (50%)) were mixed with three different solutions (distilled water, sea water and microbial solution) at liquid limit state and then their water contents were increased step by step. Then, their undrained shear strength was measured using a portable vane shear device called Torvane. The ranges of undrained shear strength at liquid and plastic limits are 3.6-9.2 kPa and 24-45 kPa, respectively. On the other hand, the water content that corresponds to the value of the undrained shear strength changing most rapidly is called flow water content. The flow limit refers to the water content when undrained shear strength of cohesive soils is zero. In order to investigate the relationship between liquid limit and flow limit, the cohesive index was defined as a value of the difference between flow limit and liquid limit. The new plasticity index was defined as the value of difference between flow limit and plastic limit. The new liquidity index was also defined using flow limit. The values of flow limit are 1.5-2 times higher than those of liquid limit. At the same time, the values of new plasticity index are 2-5.5 times higher than those of original plasticity index.

• Journal of the Korean Society of Physical Medicine
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• v.16 no.1
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• pp.73-81
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• 2021

PURPOSE: This study examined effects of the untact trunk stabilization exercise program on muscle thickness, trunk strength, maximal expiratory flow, and static balance. METHODS: The subjects were 20 normal adults divided into 10 in the contact exercise group and 10 in the untact exercise group. The trunk stabilization exercise program was conducted for four weeks. The muscle thickness was measured using ultrasound. The maximal expiratory flow was measured using Personal Best Full Range Peak Flow Meter. The static balance was measured through Bio-rescue; and the trunk muscle strength was measured by bending the upper body forward and measuring the time for maintaining the posture. RESULTS: Both contact and untact exercise groups showed significant differences in muscle thickness, muscle strength, maximal expiratory flow, and static balance (p < .05). A significant difference in muscle thickness on ultrasound was observed between the contact and untact exercise groups (p < .05). CONCLUSION: Activation of the transverse abdominal muscle requires accurate instructions of the contact exercise, but despite environmental constraints, the untact exercise program is as effective as the contact exercise for improving muscle strength, maximum expiratory flow, and static balance.

• Journal of computational fluids engineering
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• v.13 no.4
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• pp.39-44
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• 2008

Numerical simulations of laminar flow over a sphere are conducted to investigate the effect of the Reynolds number on the characteristics of vortex shedding. The Reynolds numbers considered are between 300 and 475, covering unsteady planar-symmetric and asymmetric flows. Results show that the unsteady planar-symmetric flow can be categorized into two different regimes: single-frequency regime and multiple-frequency regime. The former has a single frequency component due to periodic shedding of the vortices with the same strength in every shedding cycle, while the latter has multiple frequency components due to cycle-to-cycle variation in the strength of shed vortices with the shedding angle fixed. The multiple-frequency planar-symmetric flow, which is newly found in the present study, occurs at Re=330${\sim}$360 between the single-frequency planar-symmetric flow and the asymmetric flow. On the other hand, the asymmetric flow occurs at Re${\geq}$365, where the vortices shed from the sphere show variation both in strength and shedding angle unlike the planar-symmetric flow. Also, it is shown that the breaking of planar symmetry is closely related to the imbalance of vortical strength between a pair of streamwise vortices.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.1
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• pp.78-83
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• 2003

Electro-rheological(ER) fluids are suspensions in which rheological properties show an abrupt change with variation of electric fields. We modeled the parallel-plates relating to ER-Valve system and yielded shear stress according to the strength of electric field. The purpose of the present study is to examine the flow characteristics of ER fluids according to the strength of electric field between parallel-plates. Then the steady relationship between pressure drop and flow rate of the ER fluids between parallel-plates under application of an electric fields was measured. The pressure drop and flow rates of ER fluids under the application of electric fields for steady flow were measured. For the experiment, we used the ER fluids, 35w% zeolite having hydrous particles and differential pressure gauge. This test reviewed experiment for the special changes of ER fluids in the steady flow condition.