• The Journal of Korean Physical Therapy
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• v.23 no.1
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• pp.13-19
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• 2011

Purpose:This study was designed to investigate difference in isokinetic muscle strength in the knee extensor muscle and characteristic differences in muscle strength between males and females through the ankle joint angles. Methods: Seventy-four subjects participated in this study. There were two groups: 36 males and 38 females. The mean age of the men was 24.58 years and women was 23.74 years. Subjects were seated on a CON-TREX LP (leg press) lean to back of chair, and there bodies were fixed by straps with the hip joint at an angle of $130^{\circ}$. After randomly fixing the ankle joint at $0^{\circ}$, $20^{\circ}$, and $40^{\circ}$ of plantar flexion (PF) in range of full extension of knee joint. We studied force max average, force max average/kg, power average, and total work through the angle of the ankle joint when the knee joint was extended from $90^{\circ}$ to $180^{\circ}$. Results: In the male group, all maximum measured value showed at the ankle joint $0^{\circ}$, all minimum measured value showed at $40^{\circ}$ PF (p<0.01). In the female group, all maximum measured value showed at the ankle joint $20^{\circ}$ PF, especially the power average increased significantly. All minimum measured value showed $40^{\circ}$ PF (p<0.01). Conclusion: There are differences between males and females in isokinetic muscle strength of the knee extensor through ankle joint angles in healthy adults. Males and Females have different characteristics of muscle strength through the ankle joint angles.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.6
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• pp.755-764
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• 2016

Pressure retarded osmosis (PRO) processes can be implemented on a number of water types, using different technologies and achieving various power outcomes. In this study, Sewage facility effluent was used for feed solution of PRO and synthetic NaCl water for draw solution. This study was conducted to investigate effect of water quality of pretreatment on power density and flux decline in PRO process. The results show that organic and particulate foulants have to be removed for more stable operation. Flourescence technique with EEM enables to investigate the chemical properties of aquatic organic matter by extracting spectral information. Humic/fulvic matters and soluble microbial by-products were analyzed as the most affecting factors on the PRO performance. As a result of analyzing the whole system based on the energy consumption of the unit process, specific energy consumption(SEC) of the applicable technology for PRO pre-treatment should be about $0.2kWh/m^3$ or less.

• Korean Journal of Optics and Photonics
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• v.3 no.3
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• pp.161-166
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• 1992

The s-polarized laser beam is incident with an angle ~$-30^{\circ}$ to a uniformly rotating rough metal surface and the degree of second order temporal coherence $g_{s}^{(2)}(\tau)$ of the backscattered wave, which has the same polarization with the incident laser beam, is measured. The contribution of shot noise involved in the measurement of $g_{s}^{(2)}(0)$ is subtracted from the photoelectric signal to obtain the accurate value of $g_{s}^{(2)}(0)$.At each scattering angle$\theta_{s}$에서$g_{s}^{(2)}(\tau)$ is almost consistent with the function {1+exp($-\tau^2/\tau_0^2$)}, which is the same result with the case of the laser speckle formed by scattering on the rotating ground glass suface. In addition, a peak in the angular distribution of $\tau_0$ is observed with the maximum at$\theta_s=34^{\circ}$.It is found that the rough metallic scattering with multiple scattering over than 10% has the same function of the degree of second order temporal coherence with that of the ground glass surface scattering where the multiple scattering is ignorably small.

• Journal of Digital Convergence
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• v.17 no.3
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• pp.463-471
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• 2019

The purpose of this study was to investigate the effect of muscle imbalance on motion of back squat. The isokinetic muscle strength of the 8 subjects was recorded for the knee flexion/extension by the cybex 770 dynamometer. Each subject performed 3 back squats with the long barbell with an intensity of 25% body weight(BW), 50%BW, 100%BW, 125%BW. During the back squat through the recorded kinematic data the subjects' maximum flexion and extension knee angle, center of mass displacement and V-COP were calculated for evaluation of the stability of the movement. For the statistical analysis independent t-test was used. Knee flexion angle and COM displacement are dominated by the reciprocal muscle ratio. V-COP factor was dominated by bilateral extension deficit. Based on the results we can know that as the intensity of the squat increased to a level control was difficult because the muscles' imbalance influenced the movement.

• Journal of agriculture & life science
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• v.52 no.6
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• pp.111-125
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• 2018

In this study, we evaluated the uniformity of deposition rate and particle size distributions of the variable rate application technique using the unmanned rotorcraft by measuring the spray pattern according to path location in the range of spraying flight. The coefficient of variation (CV) of the lateral coverage rate for the overlapped distribution with the spray swath of 3.6 m in both guidance and auto-pilot flight modes maintaining constant flight speed was about 30% and the CV of the coverage rate by the flight path location was extremely small. Therefore, it was assessed that the variable rate application technology compensating for the variation of ground speed was superior in terms of spray uniformity. In addition, the droplet size distributions in both volume median diameter(VMD) and number median diameter(NMD) were adequate for aerial application and uniform in terms of lateral distribution. Thereafter, we intend to contribute to a precise application on small-scaled fields using the unmanned agricultural rotorcraft by the variable rate application.

• Journal of Advanced Navigation Technology
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• v.23 no.1
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• pp.1-7
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• 2019

Thisstudy presentsthe development of a fast-time airport surface simulator. The simulator usesthe output from a first-come first-served (FCFS) scheduler and has adopted one-dimensional dynamic model to simulate the movement of the aircraft on the surface. Higher collision risks situations in the airport surface traffic are analyzed to classify those situations into six cases. A conflict detection and resolution algorithm is implemented to maintain separation distance and to prevent deadlock. The simulator was tested with a scenario at the Incheon International Airport that contains 72 aircraft. Without the conflict detection and resolution, various conflict situations are identified. When the conflict detection and resolution algorithm is managing the traffic, it is confirmed that the conflicts are removed at the price of additional delays. In the conflict resolution algorithm, three prioritization strategies are implemented, and delayed aircraft count and average additional delays are compared. Prioritization based on remaining time or distance showed smaller total additional delay compared to choosing minimum delay priority for each situation.

• Archives of Orthopedic and Sports Physical Therapy
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• v.14 no.2
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• pp.45-53
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• 2018

Purpose: The purpose of this study was to investigate the effects of muscle activity and muscle strength according to verbal command volume during isokinetic and isometric quadricep exercises. Methods: To measure muscle activity and muscle strength, surface electrodes were attached to the participants, as they sat on a Biodex chair. The isometric exercise was performed three times, with maximum exercise at $30^{\circ}$ bending angle, based on a maximum extension state of the knee at $0^{\circ}$. The average holding time was unified to three seconds. In addition, the isokinetic exercise was performed three times, at $60^{\circ}/sec$. The verbal command ranged between 0∾60 dB and 0∾75 dB. Muscle activity was measured using surface electromyography (4D-MT, Relive, Gimhae, Korea). The Biodex System 4 was used to measure the isometric and isokinetic strength of the nodal line, and 4D-MT was used to measure muscle activity. Results: There were significant improvements in the maximal and relative muscle strengths, when the 0∾ 60 dB and 0∾75 dB verbal commands were applied with isokinetic extension/flexion (p<.05). The isokinetic exercise (0∾75 dB) group showed a significant difference in the vastus medialis oblique muscle activity change (p<.05), while the isometric exercise (0∾75 dB) group showed a significant difference in the rectus femoris muscle activity change (p<.05). Conclusions: Our results reveal that verbal commands effectively improve muscle activity and muscle strength during isokinetic and isometric quadricep exercises.

• PNF and Movement
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• v.19 no.2
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• pp.183-193
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• 2021

Purpose: The purpose of this research was to investigate the effects of performing Pilates exercises for eight weeks on the isokinetic trunk strength and balance of female middle school students with lumbago. Methods: Twenty-four female students who met the test requirements were recruited and randomly divided into a control group (CG, n = 16) and a Pilates exercise group (Pilates group; PG, n = 8). The PG performed a Pilates program, which consisted of lumbar muscle strengthening exercises, for 60 minutes three times a week for eight weeks. Data analysis was conducted by two-way repeated ANOVA, and a Bonferroni test was carried out when significant differences appeared. The alpha level was set at 0.05. Results: Following the experimental treatment, the PG showed an increased trunk flexion peak torque of 17% and 13% at angular velocities of 180°/sec and 300°/sec, respectively. The intergroup comparison showed no significant difference at pre-measurement, while the PG increased about 31% (180°/sec) and 15% (300°/sec) higher than the control group at post-measurement. Following the experimental treatment, the PG showed an increased trunk extensor peak torque of approximately 29% and 21% at angular velocities of 180°/sec and 300°/sec, respectively. The intergroup comparison showed no significant difference at pre-measurement, while the PG increased approximately 27% (180°/sec) and 15% (300°/sec) higher than the control group at post-measurement. Both the CG and the PG showed a 20% and 50% decrease in pain index after the experimental treatment, respectively. After the experimental treatment, the PG had about 50% lower pain than the CG. The average error rate of static balance in the PG reduced by 19% from 3.28±0.45 to 2.65±0.36, confirming a significant improvement. Conclusion: Regular Pilates exercise for eight weeks improved the isokinetic trunk muscle strength of female middle school students with lumbago and relieved their pain. Pilates was also shown to be effective in improving balance.

• Korean Journal of Applied Biomechanics
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• v.32 no.3
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• pp.103-110
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• 2022

Objective: The aim of this study was to investigate effect of core stabilization exercises on the erector spinae contractile properties and trunk isokinetic muscle function of middle age with low physical activity and sedentary lifestyle. Method: Twenty (female: n=10, male: n=10) middle-age subjects (age: 37.25 ± 6.08 years, height: 168.01 ± 6.84 cm, weight: 71.37 ± 11.75 kg) participated in this study. Tensiomyography was measured on the erector spinae, and the isokinetic trunk muscle function test was measured at an angular velocity of 60 °/s and 90 °/s. All subjects performed the core stabilization exercises for 60 min per day, 3 times a week, for 7 weeks. A paired t-test was performed with a significance level of 0.05. Results: Tensiomyography of the erector spinae revealed a significant post-exercise increase in the maximum radial displacement (p < .05) and velocity of contraction (p < .05), however, there wasn't a significant post-exercise change in the contraction time. Additionally, the isokinetic muscle function test of the trunk revealed a significant post-exercise increase in trunk extensor relative strength (p < .05) and strength ratio (p < .05). Conclusion: Our results indicated that core stabilization exercises reduced erector spinae muscle stiffness, increased the velocity of erector spinae contraction. Additionally, data showed the improvement in the trunk extensor strength help induce a more balanced development in trunk muscle.

• Journal of Korea Entertainment Industry Association
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• v.13 no.8
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• pp.595-602
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• 2019

The Purpose of this study was to evaluated the effectiveness of Pilates exercise in women with obesity through a review of Pilates exercise used to enhance physical function and mental function. We searched randomized controlled trials using electronic databases. We also manually reviewed sources to identify additional relevant studies. We only included research that Pilates was applied and the researches that was combined with other kinds of exercises were excluded. We have found 11 researches that is corresponded to selected criteria and the investigation was conducted by dividing into two section which are physical and psychological effect of Pilates exercise. Pilates exercise affect body composition, hormone by providing increased muscle strength, quality of life, lumbar isokinetic muscle strength, adiponectin, ghrelin and confidence, as well as decreased body fat rate, insulin, RBP-4, leptin, total cholesterol, triglyceride. Pilates exercise for women with obesity has been shown to be highly effective in lots of health related factors. Therefore we recommend Pilates exercise strongly for the life care of obesity women.