• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.62 no.1
• /
• pp.45-49
• /
• 2013

High frequency system has been used for the purpose of skin care and obesity treatment, by high-frequency energy is applied to the human body generates deep heat. Conventional high frequency system could not selection control by depending on the body load fluctuations. Such as burns and side effects have been reported by system instability and then therapeutic effect is insufficient. During treatment, objective information about the status of the patient was no. Because of treatment methods are subjective, and so tailored treatments were impossible. In this paper, high frequency medical system with sinusoidal frequency characteristics without distortion of the Push pull switching scheme for pain relief therapy was designed. And control circuit that was designed by feedback using the output changes according to the body-load fluctuation. Last, power circuit for efficient control the heat generated from the hardware was proposed.

• Journal of the Korean Society of Safety
• /
• v.15 no.4
• /
• pp.69-77
• /
• 2000

This paper presents a study for decision method of human body safety according to power load fluctuation of the Chechon area. To cope with substantial electromagnetics analysis, the safety assessments were analyzed the double 154 [kV] T/L, 345 [kV] T/L, Chechon-Ichon, Chechon-Youngju, respectively. As the results of case study, in case of 345 [kV] T/L, the electric field value was 11.4927 [kV/m], magnetic field value was 0.4622 [G] at the point about 7 [m] away from the line in severest case. The results showed that the membership of a proposition fuzzy '11.4937 [kV/m] is hazardous' is 0.7063 for the severest case in case of 345 [kV] T/L. As the analytic results using the fuzzy qualifier term, the membership in case of very false is 0.0862 and fairly false is 0.5419, respectively.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2014.11a
• /
• pp.182-183
• /
• 2014

In case of large soft body impact test at the construction site, the test conditions are different from conditions at the laboratory, and the length of rope to hold the impact specimen must be changed. In a previous study, the fact that the size of impact load is varied by the length of rope on the large soft body impact specimen was confirmed. In this study, the length of rope and fall height were set as independent variables to conduct the load analysis test. It was determined that the load fluctuation was occurred depending on the length of rope under the fall height over 100 mm, and it is concluded that the additional setup of fall height to modify the actual impact load size is required when the length of rope is below 2.5 m. In this study, the modified formula to put equal size of impact load regardless of the length of rope was extracted through the experiment.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.12
• /
• pp.169-175
• /
• 2000

Stable and comfortable walking supports, which can reduce the body weight load partially, are needed for the recovering patients from neurologic disease and orthopedic procedures. In this paper, the development of a manipulator of rehabilitation robot for the patients with walking disabilities are studied. A force controller using pneumatic actuators is designed and implemented to the human friendly rehabilitation robot considering the safety of patients, reliability of the system, effectiveness of the unloading control and economic maintenance of the system. The mechanism of the unloading manipulator is devised to improve the sensibility for the movement of the patients such as direction and velocity. For the unloading force control, fuzzy control algorithm is adopted to reduce the partial body weight and suppress the unwanted fluctuation of the body weight load to the weak legs due to the unnatural working of the patients with walking disabilities. The effectiveness of the force control is experimentally demonstrated.

• Journal of the Ergonomics Society of Korea
• /
• v.23 no.1
• /
• pp.39-48
• /
• 2004

In terms of women engaged in clerical job. working time of the workers who mainly keep standing with their high-heeled shoes on has been increasing. According]y. they are exposed to many kinds of foot deformation caused by loads of lower back and lower extremities due to high-heeled shoes. The type of heels they usually wear are diverse though the hight is same. In this study. we investigated most women's favorite styles of shoes concerned with heights. types and contact areas of the heels. Hence. we designed three kinds of shoes for an experiment: their contact areas with ground are 1 cm2. 2-4 cm2 and over 9 cm2 according to the heel heights. respectively. To investigate the biomechanical effects. analysis of motion and EMG were applied to the experiments. In addition. foot pressure distribution was measured for more detailed analysis. Six healthy young women were participated in this experiments. The result showed the heel becoming higher and narrower increased not only fluctuation of CBM(Center of Body Mass). but also the load of low back muscle and lower extremities. Accordingly. there was significant difference among types of the heel in terms of the role supporting load of the body. though the height is same. Especially. the difference among the pressures on a foot was most significant. In conclusion. we verified biomechanical effects are related with the contact area of a heel with ground as well as the hight.

• Journal of the Korean Society of Safety
• /
• v.12 no.2
• /
• pp.70-79
• /
• 1997

This paper presents a study on the fuzzy linguistic variable based approach for safety assessment of human body in ELF electromagnetic field considering power system states. To cope with the demand in modern industry, the power system becomes larger in scale, higher in voltage. The advent of high voltage system has increased the relative importance of field effects. The analysis of ELF electromagnetic field based on Quasi-Static Method is introduced while the power system is included to model the expected and/or unexpected uncertainty caused by the load fluctuation and parameter changes. In order to analyze the power system, Monte Carlo simulation method and contingency analysis method are adopted in normal state and alert state, respectively. In the safety assessment of human body, the approach based on fuzzy linguistic variable is employed to overcome the shortcomings resulting from a crisp set concept. The suggested scheme is applied to a sample system(modified IEEE 14 bus system) to validate the usefulness.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.14 no.2
• /
• pp.298-309
• /
• 1990

In this paper, a new method is suggested to analyze impulsive stresses at loading poing of concentrated impact load under certain impact conditions determined by impact velocity, stiffness of plate and mass of impact body, etc. The impulsive stresses are analyzed by using the three dimensional dynamic theory of elasticity so as to analytically clarify the generation phenomenon of cone crack at the impact fracture of fragile materials (to be discussed if the second paper). The Lagrange's plate theory and Hertz's law of contact theory are used for the analysis of impact load, and the approximate equation of impact load is suggested to analyze the impulsive stresses at the impact point to decide the ranage of impact load factor. When impact load factors are over and under 0.263, approximate equations are suggested to be F(t)=Aexp(-Bt)sinCt and F(t)=Aexp(-bt) {1-exp(Ct)} respectively. Also, the inverse Laplace transformation is done by using the F.F.T.(fast fourier transform) algorithm. And in order to clarity the validity of stress analysis method, experiments on strain fluctuation at impact point are performed on a supported square glass plate. Finally, these analytical results are shown to be in close agreement with experimental results.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.49 no.5
• /
• pp.257-263
• /
• 2000

One of the basic assumptions in the static gait design for a walking robot is that the weight of leg should be negligible compared to that of body, so that the total gravity center is not affected by swing of a leg. Based on the ideal assumption of zero leg-weight, conventional static gait has been simply designed for the gravity center of body to be inside the support polygon, consisting of each support leg's tip position. In case that the weight of leg is relatively heavy, however, while the gravity center of body is kept inside the support polygon, the total gravity center of walking robot can be out of the polygon due to weight of a swinging leg, which causes instability in walking. Thus, it is necessary in the static gait design of a real robot a compensation scheme for the fluctuation in the gravity center. In this paper, a body impedance control is proposed to obtain the total gravity center based on foot forces measured from load cells of a real walking robot and to adjust its position to track the pre-designed trajectory of the corresponding ideal robot's body center. Therefore, the walking stability is secured even in case that the weight of leg has serious influence on the total gravity center of robot.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.853-858
• /
• 2004

In order to develop a high speed train, various conditions have been considered. Fatigue strength assessment by the fluctuation of pressure is an important one. When high speed train passing though tunnels, the pressure wave is generated in tunnels and pressure variation by the wave is acting on carbody structure with dynamic load repeatedly. In this study, formulation for reliability based fatigue assessment method has been performed when the high speed train passes through tunnels. The formulation was based on structural reliability index method and followed the proposed ISO method. The result by this study would be a good guidance to calculate the fatigue life and reliability index of body structure.

• Journal of the Korean Society for Railway
• /
• v.10 no.4
• /
• pp.414-419
• /
• 2007

The contact characteristics of the current collection system are investigated by analyzing data collected during a test run of the Korean high speed rail vehicle. For the analysis, the signals from accelerometers and load cells attached to the various parts of the pantograph are analyzed in both the time and frequency domains. In the frequency domain, the pantograph response consists of low frequency components related to the rigid-body motion of the panhead assembly and high frequency components due to the structural vibration modes of the pantograph. The analysis shows that the inclusion of the high frequency structural vibration modes of the pantograph in the contact force calculation has a negligible effect on the predicted mean value of the contact force but significantly affects the magnitude of its fluctuations. This finding implies that numerical simulations using lumped element models of the pantograph may accurately predict the mean contact force but is limited in its capacity for predicting the fluctuation about the mean. Since the ratio of the fluctuation to the mean in the contact force increases with increased train speed, the limitation of the predictions based on numerical simulation results becomes more pronounced at higher train speed.