• Journal of the Ergonomics Society of Korea
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• v.22 no.2
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• pp.57-69
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• 2003

This study was performed to investigate the isometric endurance time as percentages of maximum voluntary contraction. Electromyogram(EMG) and Borg's CR-I0 value were measured by push-pull-up-down tasks for 10 healthy males. The normalized EMG value and the MPF(mean power frequency) were used to estimate the muscle recruitment pattern and the development of muscle fatigue. The subjects exerted and maintained 5 levels of %MVC(maximum voluntary contraction) in $90^{\circ}$ shoulder flexion/ 180oelbow extension at sitting posture. The up-task showed the lower endurance time and higher Borg's CR-I0 value than the other task types. Comparing Rohmert's curve with the endurance time of task types. Rohmert's curve overestimated the endurance time of up-task and underestimated the endurance time of push-pull-down tasks. The normalized EMG value showed that muscles recruitment patterns were different from task types. The 4 muscles(biceps brachii muscle, tricep brachii muscle. middle deltoid muscle. trapezius muscle) recruitment patterns of up-task were higher than those of other tasks. The MPF value decreased with the endurance time, and the shift of MPF at up-task was larger than that of the other task types.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.36-39
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• 2003

The push pull forward converter is a very suitable circuit for low output voltage, high output current applications with a wide input voltage range. All the magnetic components (output inductor, transformer, input filter) can be integrated into a single core. The integrated magnetics can reduce the number of the magnetic components. Developed the push pull forward converter rating are of 36 $\~$72V input and 3.3V/30A output. In this converter, the efficiency was measured by $76.4\%$ at full load and 82.95$\%$ at full load. The maximum efficiency is up to 83.$\%$ at 200kHz switching frequency, l1A output.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.32
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• pp.155-162
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• 1994

The Japanese "Just-In-Time" technique reduces inventory and unnecessary factors. This technique makes the success of Japanese firms, therefore many Korean firms try to apply it to their situation. But the technique doesn't bare the same success in Korean firms. This paper, therefore, considers the different situations between Korean rim and Japanese firm, then simulates the Pull system and Push system for a multiline, multistage production system. This paper drives the different results of simulation according to variable processing times, variable demand, set-up time and shortages in Pull system and Push system using GPSS. The results show that the performance of Pull system is lower than Push system's in variable master production scheduling and variable processing times.ing times.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.243-249
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• 2000

This experimental study is shows speed-up possibility for the conventional railway vehicle. We appraise derailment coefficient then increase the velocity of the kyungbu line, honam line, changhang line, kyungjeon line.

• Journal of the Ergonomics Society of Korea
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• v.32 no.4
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• pp.405-411
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• 2013

Objective: Product design process without considering the strength of the user can cause the excessive burden on musculoskeletal system of human body. Since the muscle strength will vary depending on the body posture, the design of product should consider the characteristics of body posture. This study was performed to investigate the effects of forearm postures on the push and pull strength. Background: Overexerted force has been identified to cause musculoskeletal disorders. It is important to know the push and pull strength exerted by human when designing so that exerted force does not exceed the safety limits. Method: Maximum isometric push and pull strength of left, right and both hands were measured according to forearm postures with pronation, neutral and supination. For the study, 66 male and 30 female undergraduate students were participated as subjects. All subjects were normal and healthy with no clinical history. Results: The results showed that the push strength of male and female were 93.3% and 85.4% of pull strength. It showed that the strength of one-hand was 72.1~81.0% of the strength of two-hands, and the strength of left hand was 93.1~95.8% of the strength of right hand. The strength of female was 62% of the one of male. It was found that the strength with pronation $90^{\circ}$ was reduced up to 20% compared to the strength with neutral posture. Conclusion: Push and pull strength of male and female were reduced when forearm was rotated extremely. Application: The results of this study will be used for the prevention of work related musculoskeletal disorders and design of industrial equipment.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.3
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• pp.247-255
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• 2013

In this paper, a soft switching DC-DC converter for AC module type photovoltaic (PV) module integrated converter is proposed. A push-pull converter is suitable for a low voltage PV AC module system because the step-up ratio of a high frequency transformer is high and the number of primary side switches is relatively small. However, the conventional push-pull converters do not have high efficiency because of high switching losses by hard switching and transformer losses (copper and iron losses) by high turns-ratio of the transformer. In the proposed converter, primary side switches are turned on at zero voltage switching (ZCS) condition and turned off at zero current switching (ZVS) condition through parallel resonance between secondary leakage inductance of the transformer and a resonant capacitor. Therefore the proposed push-pull converter decreases the switching loss using soft switching of the primary switches. Also, the turns-ratio of the transformer can be reduced by half using a voltage-doubler of secondary side. The theoretical analysis of the proposed converter is verified by simulation and experimental results.

• The Journal of the Acoustical Society of Korea
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• v.21 no.1
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• pp.27-36
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• 2002

VoiceXML is a standard dialog mark-up language for the neat generation voice applications. The current VoiceXML 1.0 specification is silent on who place outbound calls for push-based voice applications. The push-barred voice applications become very important in modern information systems such as CRM. In this paper, we design and implement an extended VoiceXML platform that supports both inbound and outbound voice information services. We also extend the VoiceXML DTD so as to be able to inbound/outbound fax based on Call Control Requirements of W3C.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.4
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• pp.100-108
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• 1997

A combined buck and boost push-pull quantum series resonant rectifier(PPQSRR) is newly proposed to achieve a power factor correction without start-up inrush current. Based on the developed dynamic modeling of the proposed rectifier, an inrush current elimination control technique is proposed and the usefullness of the proposed rectifier and control method are verified by computer simulation and experimental results. With the proposed control method, a high power factor and wide range of output voltage can be obtained.

• Journal of Korean Physical Therapy Science
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• v.24 no.1
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• pp.49-58
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• 2017

Purpose: To determine the effect of Functional movement screen(FMS) of Healthy subjects. Method: 18 subjects were randomly assigned toFunctional movement screen test. To measure functional movement screen(deep squat, hurdle step, in line lunge, shoulder mobility reaching, active straight leg raise, trunk stability push up, rotary stability). Result: FMS scores were deep squat 2.61score, right hurdle step 2.67 score, lift hurdle step 2.83 score, in line lunge 2.83 score, right shoulder mobility 2.67 score, left shoulder mobility 2.61 score, right active straight-leg raise 3.00 score, left active straight-leg raise 3.00 score, trunk stability push up 2.33 score, rotary stability 1.94 score. Conclusion: FMS can improve functional movement in healthy adults.

• Journal of Power Electronics
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• v.1 no.2
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• pp.78-87
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• 2001

A new high-power step-up based on the two-module parallel-input (PISO) modular dual inductor-fed push-pull converter is proposed. The proposed converter is operated at a constant duty cycle and employs and auxiliary circuit to control the output voltage with a phase-shift between two modules. It shows a high efficiency due to the greatly reduced switch turn-off stress. It also shows a high and linear voltage conversion ratio, low current stress in the output capacitor, and fast control-to-output dynamics. The operation principles and the mathematical models of the proposed converter are presented. Features of the proposed converter are discussed in comparison with the two-module PISO modular dual inductor-fed push-pull converter. Also, experimental results from a 50kHz, 800W, 350 Vdc prototype with an input voltage range of 20-32 Vdc are provided to confirm the validity of the proposed converter. The new converter compares favorably with the conventional counterpart, and is considered well siuted to high-power step-up applications.