• Journal of Institute of Control, Robotics and Systems
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• 제20권8호
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• pp.835-841
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• 2014

In this paper we propose a swing-up strategy for a single inverted pendulum. The proposed method has a feature whereby can handle the input and output constraint of a pendulum in a systematic way. For the swing-up of a pendulum, we adopt a 2-DOF control structure that combines the feedforward and feedback control. In order to generate the swing-up feedforward trajectories that satisfy the input and output constraint, we formulate the problem of generating feedforward trajectories as a nonlinear optimal control problem subject to constraints. We illustrate that the proposed method is more flexible than the existing method and provides great freedom in choosing the actuator of the inverted pendulum. Through an experiment, we show that the proposed method can swing a pendulum upward effectively while satisfying all the imposed constraints.

• The Journal of Korean Physical Therapy
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• 제21권1호
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• pp.89-96
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• 2009

Purpose: The purpose of this study was to determine the effect of modified golf swing training on gait characteristic in hemiplegic patient through Kwon 3D motion analysis system. Methods: This study has performed single subject design from September to October 2008. The subject had left hemiplegia due to CVA in December 2003. He has treated Bobath approach twice a week. In order to increase ankle dorsiflexion and knee flexion, the subject has applied modified golf swing training on the basis of Bobath approach. The measurement of gait characteristic was taken by Kwon 3D motion analysis system. Results: The results were as follows : 1) Walking velocity was increased 0.62m/sec than before the training. 2) Step length was increased 0.09m than before the training. 3) Left ankle and hip angle were increased, but left knee angle was decreased. Conclusion: It could be concluded that the activity modified golf swing training in walking pattern contributed to improve the movement quality and speed of gait.

• Korean Journal of Applied Biomechanics
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• 제25권3호
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• pp.301-309
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• 2015

Objective : The purpose of this study was to describe the correlation between the activity of the muscles of upper and lower limbs of a golf driver swing according to shoulder injury. Method : The subjects were 18 professional golfers (7 male in KPGA and 11 female in KLPGA). Using surface electromyography, we evaluated muscle activities during the golf drive swing. Surface electrodes were used to record the level of muscle activity in the left Deltoid(MD), Triceps Brachii(TB), Pectoralis(PM), Trapezius(UT), Rectus Femoris(RF), Vastus Medialis Obilique(VMO), Biceps Femoris(BF), Gastrocnemius(GCM) muscles during the golfer's swing. The golf swing was divided into five phases: take away, forward swing, acceleration, early follow through, late follow through. Results : The results can be summarized as follows: MD, VMO had statistically significant difference in take away phases, GCM had statistically significant difference in acceleration phases, MD, PM, VMO had statistically significant difference in early follow through phases, PM had statistically significant difference in late follow through phases, Conclusion : Muscle activity of the 8 muscles(Deltoid, Triceps Brachii, Pectoralis, Trapezius, Rectus Femoris, Vastus Medialis Obilique, Biceps Femoris, Gastrocnemius) along the shoulder damage or absence of has shown that they are organically connected to each of the phases.

• Korean Journal of Applied Biomechanics
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• 제21권1호
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• pp.85-95
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• 2011

Three-dimensional(3D) motion analysis is a useful tool for analyzing sports performance. During the last few decades, advances in motion analysis equipment have enabled us to perform more and more complicated biomechanical analyses. Nevertheless, considering the complexity of biomechanical models and the amount of data recorded from the motion analysis system, subsequent processing of these data is required for event-specific motion analysis. The purpose of this study was to develop a basic golf swing analysis algorithm using a state-of-the-art VICON motion analysis system. The algorithm was developed to facilitate golf swing analysis, with special emphasis on 3D motion analysis and high-speed motion capture, which are not easily available from typical video camera systems. Furthermore, the developed algorithm generates golf swing-specific kinematic and kinetic variables that can easily be used by golfers and coaches who do not have advanced biomechanical knowledge. We provide a basic algorithm to convert massive and complicated VICON data to common golf swing-related variables. Future development is necessary for more practical and efficient golf swing analysis.

• Proceedings of the KSME Conference
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• 대한기계학회 2003년도 추계학술대회
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• pp.881-886
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• 2003

In spite of its simple design, structure and operating mechanism, swing check valves are one of the critical components which adversely affect the safety of the nuclear power plants if they fail to function properly. Therefore, it is important to evaluate the performance condition of the swing check valves in safety-related systems. The performance characteristics of swing check valves include opening characteristics, the minimum required flow velocity, the pressure drop at design flow, the disc stability, and the effect of the upstream disturbances. Among factors to identify the performance of a swing check valve, a method to evaluate the opening characteristics and the minimum required flow velocity, which guarantees to fully open the disc and hold the disc without motion, are presented to determine the operating region of the swing check valve, such as stable, tapping, or oscillation. Based on the determined operating region and opening characteristics, the simple methods of wear and fatigue analyses of the specific parts of the valve are also described.

• The KSFM Journal of Fluid Machinery
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• 제8권6호
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• pp.15-25
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• 2005

Check valves playa vital role in the operation and protection of nuclear power plants. Check valves failure in nuclear power plants often lead to a plant transient or trip. The analysis of historical failure data gives information on the populations of various types of check valves, the systems they are installed in, failure modes, effects, methods of detection, and the mechanisms of the failures. A majority of check valve failures are caused by improper application. The experimental apparatus is designed and installed to measure the disc positions with flow velocity, Vopen and Vmin for 3 inch and 6 inch swing check valves. The minimum flow velocity necessary to just open the disc at a full open position is referred to as Vopen, and Vmin is defined as the minimum velocity to fully open the disc and hold it without motion. In the experiments, Vmin is determined as the minimum flow velocity at which the back stop load begins to increase after the disc is fully opened or the oscillation level of disc is reduced below $1^{\circ}$. The results show that the Vmin velocities for 3 inch and 6 inch swing check valves are about 27.3% and 17.5% higher than the Vopen velocities, respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.643-644
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• 2006

The purpose of this study is to experimentally analyze swing motion with soft golf clubs and compare with that with normal golf clubs. Soft golf is newly devised recreational sport based on golf but focus on the playability for the elderly. The subject fur the experiment performed swing motion using a normal golf club and a soft golf club in turn. The swing motion of the subjects was tracked using an opto-electric three-dimensional motion analysis system. The results were compared against those obtained with a normal golf club. The range of motion was analyzed along with top head speed for two cases. It was found that higher club head speed could be achieved with reduced range of motion at lumbar joint using soft golf club when compared against the swing using regular club. The lower range of motion fur lumbar bending means reduced risk of injury at the joint. So, it is projected that we can reduce the risk of injury with soft golf while maintaining the club head speed.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.111.1-111.1
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• 2011

Recently, comsumption of fossil fuel is causing many problems(oilflation, global warming, environmental pollution). For this reason Renewable energy is now becoming the center of interest as a solution to these problems. Bioethanol, especially, is able to substitute petroleum as fuel; making it a viable and promising renewable energy. In order to production of fuel bioethanol, Dehydration process is essential. Azeotropic distillation, extractive and pressure swing absorption(PSA) process are some of possible dehydration process, out of which, PSA process is attractive since it required less energy and lower setup cost. In this study, we produced fuel bioethanol using 2-step PSA(3 bed + 2 bed) process for more efficient and economical process. Through this study, we produced fuel bioethanol using 2-step PSA process and concentration of fuel bioethanol was 99.54wt%(feed ethanol: 92.4wt%). We expected that because of efficient use of absorbents(zeolite), 2 step PSA process contribute to economical operation.

• Korean Journal of Psychosomatic Medicine
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• 제15권1호
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• pp.14-21
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• 2007

Premenstural dysphoric disorder(PMDD) imposing 4-5% of women is possibly caused by an enhanced responsiveness to the changes of sex steroid hormones and the decrease of serotonin, melatonin and GABA. The common clinical features between PMDD and depression, seasonal affective disorder, panic disorder and anorexia nervosa suggest a relatedness between PMDD and each of them. The diagnostic criteria of DSM-IV-Tr for PMDD requires psychological symptoms, that commonly include irritability, anger, depression, mood swing, affect lability, tension, anxiety, fatigue and food craving. As of today, the best pharmacological treatment for PMDD is the selective serotonin reuptake inhibiter, and leuprolide, danazol, estradiol, spironolactone and bromocriptine are possible alternatives. Nonpharmacological treatments for patients with mild to moderate symptom severity are diet, exercise, light therapy, psychotherapy and keeping a diary.

• Journal of the Korean Society of Manufacturing Process Engineers
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• 제17권1호
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• pp.1-7
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• 2018

We aimed to develop a high quality 3.5 ton class swing reducer by studying the efficiency improvement of the reducer through the optimum design and performance evaluation of the assembled, high efficiency, lightweight 3.5 ton swing reducer. Based on the optimal design of the worm and worm wheel, the optimal manufacturing method of the worm wheel, the optimized casing design, and the optimum design of the output pinion, Respectively. Therefore, in this paper, to improve the efficiency of the worm gear reducer system, we will develop the manufacturing technology and verify the mass production by combining the manufacturing process design, processing and assembling technology according to the optimization design. We have conducted research to realize mass production by product verification such as product efficiency, reliability and durability according to optimal design of worm gear reducer.