• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.4
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• pp.76-85
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• 1993

The purpose of this study was to analyze the wind force distribution on the two single-span arched plastic house depending upon the house spacing and wind direction, which may provide the fundamental criteria for the structural design. In order to specify the wind force distribution, the variation of the wind force coefficients, the mean wind force coefficients and the drag force coefficients were estimated from the wind tunnel test data. The results obtained are as follows : 1. At the wind direction of 90$^{\circ}$, there was a typical span interval at which the maximum negative pressure was occured at the edge of the inside walls. 2. In the consideration of wind loads, the wind force coefficients estimated from independent single-span arched plastic house should not be directly applied to the structural design on the double houses separated. 3. The average maximum negative wind force on the inside walls was occured at the wind direction of 90$^{\circ}$, and the variations depending on the span intervals was not significant. 4. The average maximum drag force was occured at the wind direction of 300, and the magnitude of drag force was more significant at the first house. As the distance between two houses was increased, the drag force was slightly increased for every wind direction.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.175-178
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• 1997

This study was carried out to obtain an analytical expression for the specifications of the Stewart Platform that minimize the maximum force acting on the hydraulic cylinder. The position and orientation of the platform were calculated by means of the inverse kinematic analysis. The maximum force to be exerted on a cylinder was calculated using the Newton's second law for the case when the platform is moved along a horizontal axis with 0.6 g, the maximum translational acceleration possible. This paper suggests a mathematical model to minimize the maximum actuating force using radius and angle ratios as design variables. Finally, a fuzzy set for the minimum actuating force is proposed for this dynamic optimal design problem.

• Journal of Oral Medicine and Pain
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• v.12 no.1
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• pp.47-52
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• 1987

In order to evaluate the effect of signs and symptoms of temporomandibular disorders on the bite force of anterior teeth, the author estimated a feature of maintaining the maximum bite force on central incisors in Korean 34 adult females with signs and symptoms of temporomandibular disorders (TMD group) and in Korean 31 adult females within normal masticatory function far from any sign or symptom of TMD (control group), and analyzed the data statistically. The obtained results were as follows: 1. There was not a significant difference of the maximum bite force on central incisors between TMD group and control group (P>0.05). 2. The duration of maintaining the maximum bite force on central incisors in TMD group was shorter than it in control group (P<0.01).

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.188-191
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• 2001

Generally, main factors of tool damage are cutting speed, feed rate and depth of cut. The increase of those factors can cause tool breakage or worsen product quality such as machining accuracy deterioration. Those three factors are concerned with cutting force. Cutting force reaches at its maximum value when cutter blade cuts away the object directly, and it is the time when tool damages are at high probability. In this study, we detect the maximum cutting force affecting tool damage and control the maximum cutting force based on the measured peak force.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.6
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• pp.998-1005
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• 2010

Rifling force has a torsion impulse effect on the gun tube and thus generates undesirable vibration of the gun tube about its bore axis, putting additional stress on the projectile. High rifling force at the muzzle of the gun tube may adversely influence the trajectory of the projectile. And, the service life of rifled gun barrels is known to depend on the rifling force. Rifling force along the path of the projectile in the longitudinal direction of the gun tube can be described with projectile mass, projectile velocity, gas pressure curve and rifling angle. Under the same conditions, the character of the rifling of the gun barrel decisively influences the rifling force curve. To reduce the above mentioned harmful effect, locally distinct maximum of rifling force has to be avoided and maximum rifling force needs to be minimized. The best way to minimize the maximum rifling force is to design a rifling angle function so that the rifling force curve has a near trapezoidal shape. In this paper a new approach to make the optimal rifling force curve is described. The rifling angle determining the rifling force is developed by combined Fourier series and polynomial function to satisfy both the convergence and boundary condition matching problems.

• Journal of Oral Medicine and Pain
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• v.15 no.1
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• pp.27-35
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• 1991

In order to evaluate muscular activity patterns of masticatory muscles and asymmetry patterns of muscular activity according to the levels of occlusal force, twenty-one individuals of age ranged from 23 to 27 years were examined. They were selected according to the following criteria : 1) no symptoms of temporomandibular disorder, 2) complete dentition except third molars, 3) normal or Angle's class I molar relationship and 4) no experience of dental treatment. The electromyographic amplitudes was measured for evaluation of muscular activity and asymmetric patterns of masseter and anterior temporal muscle during unilateral clenching at the levels of 10%, 20%, 40% and 50% of the maximum occlusal force by use of electromyogram and bite force meter. The obtained results were as follows : 1. The muscle activity indices of masticatory muscles of clenching side at the clenching levels of 10%, 20% and 30% of the maximum occlusal force were -19.12, -9.87, -0.49%, so that activity of anterior temporal muscle was dominant than that of masseter muscle. At the levels of 40%, 50% of the maximum occlusal force, muscle activity indices were 4.68%, 6.70%, so that activity of masseter was dominant at all level and as the levels of occlusal force was increased, muscular activity index was tend to decrease. 2. In masseter, asymmetry indices of muscular activity at the levels of 10%, 20% of maximum occlusal force were -10.34 and -1.24%, so that muscular activity of non-clenching side were dominant and at the levels of 30%, 40% and 50% each of maximum occlusal force, muscular activity was dominant on clenching side as 4.68, 7.18 and 10.9%. In anterior temporal muscle, asymmetry indices were 33.38%, 25.46, 2095, 10.23 and 15.45% at the levels of 10%, 20%, 30%, 40% and 50% each of maximum occlusal force, so that activity of clenching 15.45% at the levels of 10%, 20%, 30%, 40% and 50% each of maximum occlusal force, so that activity of clenching side was dominant than that of non-clenching side at all levels, but as the levels of occlusal force was increased, asymmetry indices of muscular activity was tend to decrease. 3. Between both sides, average electromyographic amplitudes of masseter and anterior temporal muscle were correlated, so that as the levels of occlusal force was increased, average electromyographic amplitudes of both side in same muscle were increased proportionally. But asymmetry indices between muscular activities of masseter and anterior temporal muscle were not correlated.

• Journal of Bio-Environment Control
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• v.1 no.2
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• pp.142-147
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• 1992

The wind pressure distributions were analyzed to provide fundamental criteria for the structural design on the two-span arched house according to the wind directions through the wind tunnel experiment. In order to investigate the wind force distributions, the variation of the wind force coefficients, the mean wind force coefficients, the drag force coefficients and the lift force coefficients were estimated using the experimental data. The results obtained are as follows : 1. The variation of the wind force with wind directions on the side walls was the greatest at the upwind edge of the walls. 2. The maximum negative wind force along the length of the roof appeared at the upwind edge at the wind direction of 60$^{\circ}$. 3. The maximum negative wind force along the width of the roof appeared at the width ratio and wind direction of 0$^{\circ}$ and 0.4 in the first house and 0.6 and 30$^{\circ}$ in the second house, respectively. 4. The mean negative wind force on the side walls of the first house at the wind direction of 0$^{\circ}$ was far greater than that of the second house, and the maximum negative wind force on the roof occurred at the wind direction of 30$^{\circ}$. 5. The maximum lift force appeared on the second house at the wind direction of 30$^{\circ}$, but the lift force on the first house was far greater than that on the second house at the wind direction of 0$^{\circ}$. 6. The parts to be considered for the local wind forces were the edges of the walls, and the edges of the x-direction and the width ratio, 0.4 of the y-direction in the roofs.

• Korean Journal of Food Science and Technology
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• v.17 no.6
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• pp.469-473
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• 1985

The typical force-distance curves by puncture test and Back Extrusion test of acorn flour gels were investigated. Kc' and Ks' were calculated to estimate the compression and shear components of a puncture force. In this study, compression effect played a major role. The more concentration of acorn flour gel and diameter of probe increased, the more compression force contributed to the puncture force. In the Back Extrusion test, the effect of increasing the sample size was to extend the length of the plateau without affecting the maximum force. However, as the concentration of acorn flour gel increased, maximum Extrusion force became larger.

• Journal of Oral Medicine and Pain
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• v.10 no.1
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• pp.63-71
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• 1985

A kinematical study of bite force during voluntary isometric contraction was investigated in 20 Korean men with TMJ dysfunction and 30 Korean men as normal subject, ranging from 20 to 27 years old. The author observed maximum bite force, slope of bite force graph, curve index and duration of maximum bite force with the use of the foil strain gauge (MPM-3000) and RS Dymograph (Beckman). The obtained results were as follows : 1. Maximum bite forces were 29kg and 29kg for left and right side of normal subject (p>0.05) and 19kg and 29kg for affected and non-affected side of TMJ dysfunction patient. 2. The slopes of bite force graph were $68^{\circ}$ and $68^{\circ}$ for left and right side of normal subject (p>0.05) and $59^{\circ}$ and $71^{\circ}$ for affected and non-affected side of TMJ dysfunction patient. (p<0.01) 3. The curve indices were 0.93 and 0.90 for left and right side of normal subject and 1.10 and 0.90 for affected and non-affected side of TMJ dysfunction patient. (p>0.05) 4. The durations of maximum bite force were 424 msec and 413 msec for left and right side of normal subject and 337 msec and 334 msec for affected and non-affected side of TMJ dysfunction patient. (p>0.05)

• Korean Journal of Applied Biomechanics
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• v.23 no.3
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• pp.225-233
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• 2013

The purpose of this study was to estimate the potential injury via analyzing ground reaction force components that were resulted from a prolonged-run-induced fatigue. For the present study, passive and active components of the vertical ground reaction force were determined from time and frequency domain. Shear components of GRF also were calculated from time and frequency domain. Twenty subjects with rear foot contact aged 20 to 30, no experience in injuries of the extremities, were requested to run on the instrumented tread-mill for 160 minutes at their preference running speed. GRF signals for 10 strides were collected at 5, 35, 65, 95, 125, and 155 minute during running. In conclusions, there were no significant difference in the magnitude of passive force, impact load rate, frequency of the passive and active components in vertical GRF between running times except the magnitude of active force (p<.05). The magnitude of active force was significantly decreased after 125 minute run. The magnitude of maximum peak and maximum frequency of the mediolateral GRF at heel strike and toe-off have not been changed with increasing running time. The time up to the maximum peak of the anteroposterior at heel-strike moment tend to decrease (p<.05), but the maximum peak and frequency of that at heel and toe-off moment didn't depend significantly on running time.