• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.1-10
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• 2008

This study analyzed the rear foot angle of the supporting leg and the anatomical rotation angle of the kicking angle in soccer instep kick and drew conclusions as follows. When the supporting leg was landing on the ground, the valgus angle of the ankle joint reached the maximum peak, and plantar flexion was slightly different in the timing of the maximum peak between the two groups. The flexion angle of the rear foot was statistically significantly different between the two groups, and the movement of the crus on the landing of the supporting foot did not show a statistically significant difference between the groups. The crus leaned backward most before the impact, and the side to side gradient of the crus on impact was $22^{\circ}$. The flexion/extension of the hip joint of the kicking leg reached the maximum peak when the supporting foot was landing on the ground, and at the moment, the maximum extension angle of the hip joint was over $30^{\circ}$. The flexion angle of the knee joint of the kicking leg was largest after landing. While the maximum plantar flexion angle and maximum valgus angle of the ankle joint were not significantly different between the two groups, the maximum external rotation angle was significantly different.

• Korean Journal of Applied Biomechanics
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• v.22 no.1
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• pp.105-111
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• 2012

The purpose of this study was to investigate the effect that difference in forefoot of shoe flexibility during the quick lunge from a jump smashing on the lower limbs and the plantar pressure distribution. For this 10 elite badminton players with over 10 years experience and right handed participated. Two kinds of badminton shoes were selected and tested mechanical testing for the forefoot flexibility. Motion analysis, ground reaction forces and plantar pressure distribution were recorded. It was required to conduct lunge movement after jumping smashing as possible as high. Photo sensor was located in 3 meter away from standing position and its height was 40 cm. Subjects were conducted to return original position after touching the sensor as under clear movement as possible as fast. Forefoot stiffness had an effect on shoe peak bending degree and peak bending angular velocity in propulsion phase. Forefoot flexibility had an effect on ankle plantar flexion and knee flexion moment. It appears that joint power on lower limb and peak plantar pressure were not influenced by the flexibility of shoes.

• Magazine of the Korean Society of Agricultural Engineers
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• v.23 no.3
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• pp.78-87
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• 1981

This study was attempted to get dimensionless unit hydrograph by linear model which can be used to the estimation of flood for the development of Agricultural water resources and laid emphasis on the application of dimensionless unit hydrographs for the ungaged watersheds by applying linear model. The results summarized through this study are as follows. 1.Peak discharge is found to be Qp= CAR (C =0. 895A-o.145) having high significance between peak discharge, Qp and effective rainfall, R within the range of small watershed area, 84 to 470km2. consequently, linearity was acknowledged between rainfall and runoff. Reasonability is confirmed for the derivation of dimensionless unit hydrograph by linear model. 2.Through mathematical analysis, formula for the derivation of dimensionless unit hydrograph was derived. qp--p=(tp--t)n-1[e-(n-1)](tp--t-1) 3.Moment method was used for the evaluation of storage constant, K and shape parameter, n for the derivation of dimensionless unit hydrograph. Storage constant, K is more closely related with the such watershed characteristics as length of main stream and slopes. On the other hand, the shape parameter, n was derived with such watershed characteristics as watershed area, river length, centroid distance of the basin and slopes. 4.Time to peak discharge, Tp could be expressed as Tp=1. 25 (√s/L)0.76 having a high significance. 5.Dimensionless unit hydrographs by linear model stood more closely to the observe dimensionless unit hydrographs On the contrary, dimensionless unit hydrographs by S.C. S. method has much difference in comparison with linear model at the falling limb of hydrographs. 6.Relative errors in the q/qp at the point of 0.8 and 1.2 for the dimensionles ratio by linear model and S. C. S. method showed to be 2.41, 1.57 and 4.0, 3.19 percent respectively to the q/qp of observed dimensionless unit hydrographs. 7.Derivation of dimensionless unit hydrograph by linear model can be accomplished by linking the two empirical formulars for storage constant, K, and shape parameter, n with derivation formular for dimensionless unit hydrograph for the ungaged small watersheds.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.161-169
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• 2008

The purpose of this study was to investigate kinetic variables of the lower extremity during walking on three different stair widths in healthy adults. Ten healthy college-aged adults($23.5{\pm}3.5$) recruited for this study. Each stairs with the same height and length(l8cm and 90cm) under the Korean Constructional Law but three different widths(26cm, 31cm and 36cm) were conducted for this study. One force plate(9286AA, Kistler Co.) was put on third stairs. One-way ANOVA was performed to find the stair width effects during stair walking and the following findings ware obtained. There was significantly decreased in ankle resultant joint moment at Pull-Up phase(p<.05) and, significantly increased in knee extension moment during mid-stance phase as stair width increase(p<.05), but there was no significance in ankle resultant joint moment was found at Forward Continuance Phase in Ascending Stair Walking and There was significantly increased in ankle resultant joint moment as stair width increase during mid-stance phase(p<.05) and no significance in knee and hip resultant moments among the stair width in descending stair walking.

• Journal of Korean Society of Steel Construction
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• v.22 no.3
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• pp.281-291
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• 2010

In this study, a five-story steel frame was designed in accordance with KBC2005 to evaluate the effects of the beam-column connection on the structural behavior. The connections were designed as fully rigid and semi-rigid. The fiber model was used to describe the moment-curvature relationship of the steel beam and the column, the power model for the moment-rotation angle of the semi-rigid connection and the three-parameter model for the hysteretic behavior of the steel beam, column, and connection. The structure was idealized as separate 2-D frames and as connected 2-D frames. The peak ground accelerations of four earthquake records were modified in a time-history analysis for the levels of the mean return period and for the maximum base-shear force in a pushover analysis. The top story displacement, base-shear force, story drift, demanded ductility ratio for the semi-rigid connection, maximum bending moment of the column, beam, and connection, and distribution of the plastic hinge were examined in the time-history analysis. The frame with the semi-rigid connection yielded a lower base-shear force, less magnitude, and increasing ratio in the bending moment of the column, beam, and connection than the frame with a fully rigid connection. The TSD connection was deemed to have secured the economy and safety of the sample structure that was subjected to seismic excitation for the Korean design level.

• Physical Therapy Korea
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• v.25 no.3
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• pp.19-26
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• 2018

Background: Genu varum is also known as bow leg. It is a deformity wherein there is lateral bowing of the legs at the knee. it does give rise to pain, and persistent bowing can often give rise to discomfort in knees, hips and ankles. Objects: This study investigated the effect of narrow squats on the knee joint during a gait and distance between the knees of person with genu varum. Methods: This study analyzed 23 patient with genu varum that grade III, 12 narrow squat group and 11 genenal squat group in motion analysis laboratory. The subjects of experiment took gait before and after intervention, the range of joint motion, moment of knee joint adduction, power, distance of the knees were measured. And in order to make an analysis between groups, an paiered t-test and independent t-test was carried out. For statistical significance testing, it was decided that significance level ${\alpha}$ be .05. Results: It was shown that the group of narrow squat exercise significantly decreased in distance of knees (p<.05),In moment of adduction of knee joint, it was shown to significantly decrease in two groups (p<.05), was significantly decreased in adduction, abduction, and rotation (p<.05). In relation of peak-knee adduction moment and valgus angle, there was significant decrease in narrow squat group (p<.05). Conclusion: When the above result of study were examined, a narrow squat exercise given to the genu varum patients significantly decreased the distance between the knees, range of knee adduction and abduction, knee adduction moment, knee power. And stability gains through the decrease of excursion of knee medial part be effective for the correction of genu varum deformation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.2
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• pp.84-91
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• 2022

This study investigated the behavior of out-of-plane skewed moment connections that were designed as IMFs, as per the Korean standards. A total of 14 finite element models were constructed with the consideration of two types (single- and double-sided connections) and four levels of skew angle (0°, 10°, 20°, and 30°). The results indicated that the skewed connections considered in this study met the acceptance criteria for IMFs given by the codes. However, the load-carrying capacities of skewed connections were decreased as the skew angle increased. For the connection with a skew angle of 30°, the peak load was noted to be 13% less and the energy dissipation capacity could be 26% less than that of non-skewed connection. In addition, because of the skewed nature, the stress distribution in the skewed beam flange near the connection was asymmetric and the stresses were concentrated on the beam inner flange. Column twisting induced by the skewed configuration was very small and negligible in the beam and column combination considered in this study.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.541-546
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• 1998

The objective of this research is to observe the actual response of low-rise nonseismic moment-resisting infilled reinforced concrete frame subjected to varied levels of earthquake ground motions. First of all, the reduction scale for the model was determined as 1 : 5 considering the capacity of the shaking table to be used. This model was, then, subjected to the shaking table motions simulating Taft N21E component earthquake ground motions, whose peak ground accelerations(PGA`s) were modified to 0.12g, 0.2g, 0.3g, and 0.4g. The global behavior and failure mode were observed. The lateral accelerations and displacements at each story and local deformations at the critical portions of structure were measured. Before and after each earthquake simulation test, free vibration tests were performed to find the changes in the natural period of the model.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.607-612
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• 1998

In this study, the behavior of R/C beam strengthened with carbon fiber laminate(C.F.L) is analyzed from the test results. Test parameters are the width, the thickness and the length of C.F.L. and method of construction. The failure mode and ultimate load are analyzed from these measured data. Test results shows that the peak moment of specimens strengthened with C.F.L is increased to 1.43~1.90 times of that of non-rehabilitation specimen. The wider lap width, larger amount of rehabilitation materials, the larger strength is obtained.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.427-432
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• 1998

The objective of this research is to observe the actual response of low-rise nonseismic moment-resisting reinforced frame subjected to varied levels of earthquake ground motions. First of all, the reduction scale for the model was determined as 1 : 5 considering the capacity of the shaking table to be used. This model was, then, subjected to the shaking table motions simulating Taft N21E component earthquake ground motions, whose peak ground accelerations(PGA's) were modified to 0.12g, 0.2g, 0.3g, and 0.4g. The global behavior and failure mode were observed. The lateral accelerations and displacements at each story and local deformations at the critical portions of structure were measured. The base shear was measured by using specially made load cells. Before and after each earthquake simulation test, free vibration tests were performed to find the changes in the natural period and damping ratio of the model.