• PNF and Movement
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• v.17 no.3
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• pp.401-409
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• 2019

Purpose: This study investigated the muscular activity of abdominal muscles during a variety of plank exercises following changes in the leg and head positions. Methods: Thirty healthy individuals participated in this study. They performed six variations of plank exercises, including three changes in head position and two changes in leg position. Each plank was defined as head neutral-leg neutral, head up-leg neutral, head down-leg neutral, head neutral-leg wide, head up-leg wide, and head down-leg wide. During the plank excises, the muscle activities of the rectus abdominis, internal oblique, erector spinae, and upper trapezius were measured. Results: The head down position significantly increased the rectus abdominis activity compared to other head positions (p<0.05). On the other hand, the upper trapezius muscle activity was significantly higher with the head up position compared to other head positions (p<0.05). Regardless of head positions, both the rectus abdominis and internal oblique muscles were significantly activated with leg wide position compared to the leg neutral position (p<0.05). Conclusion: Head and leg positions could change the muscular activities of abdominal muscles during plank exercises. For example, the head down position is effective for activating the rectus abdominis while the leg wide position could be advantageous for enhancing the internal oblique and rectus abdominis.

• Design & Manufacturing
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• v.15 no.1
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• pp.1-7
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• 2021

The position of the gate is one of the important factors for optimal injection molding. This is because inappropriate gate positions cannot fill the cavity uniformly, which can lead to defects such as contraction. In this study, CAE was performed on hot runner injection molding of the washing machine base and plasticity was compared by changing gate position from existing gate position. A total of two alternatives have been applied to compare the plasticity of the washing machine base according to its optimal gate position. The gate position of the improved molds and the gate position of the current mold is analyzed by injection molding analysis. The results of the fill time, the pressure at V/P switchover, clamping force, and deflection were compared. In washing machine base injection molding, the deflection was reduced by about 3.76% in the improved mold 2. In improved mold 1, the fill time during injection molding was reduced by 3.32% to enable uniform charging, and the clamping force was reduced by 31.24%. We have confirmed that the position of the gate can change the charging pressure and the clamping force and affect the quality and cost savings of the molded product.

• Physical Therapy Korea
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• v.7 no.2
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• pp.35-54
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• 2000

The purposes of this study were to assess variation of body sway prior to and after submaximal treadmill exercise; to determine the time course of the effects of a fatiguing performed on a treadmill on body sway; and to compare position sense prior to and after exercise in order to assess any variance in proprioception caused by submaximal treadmill exercise. The subjects were twenty-four healthy men in their twenties. They stood barefoot on the Kinesthetic Ability Training Balance Platform to measure body sway. Control trials were performed with eyes alternately open and closed. In the eyes open condition, they were asked to look at a target placed at eye level 1 m in front them. A total of 10 trials, each lasting 20 seconds, were performed. After this series of trials, position sense was measured. Subjects then exercised on the treadmill until 85% of each person's maximal heart rate was reached. The first series of postural sway measurements began immediately after this exercise. The second identical series of postural sway trials was performed at approximately 10 minutes after exercise. The third series was performed approximately 20 minutes after exercise. This allowed approximately 5 minutes of rest between each experimental series. Position sense was measured at approximately 15 and 25 minutes after exercise. The results were as follows: 1) There was a significant increase in body sway after submaximal treadmill exercise compared to pre-exercise values under both visual conditions (p<.05). 2) After submaximal treadmill exercise, under the eyes open condition, the mean value of body sway was significantly increased after both the first and second series (p<.05). Under the eyes closed condition, the mean value of body sway increased significantly after the first series but decreased significantly after the third series (p<.05). 3) Position sense, measured repeatedly after submaximal treadmill exercise, did not change significantly with respect to pre-exercise values (p>.05). These results suggest that fatigue induced by submaximal treadmill exercise produced an increase in body sway in young healthy subjects with or without visual input, but the increase appeared to be lasting less than 15 minutes. No significant change in position sense suggested that proprioception was unaffected by submaximal treadmill exercise-induced fatigue.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.5
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• pp.837-844
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• 2013

This study performs erection of a pendulum hanging at a free end of an arm by rotating the arm to the upright position. A mathematical model of a rotary inverted pendulum system (RIPS) is derived. A brain emotional learning based intelligent controller (BELBIC) is designed and used as a controller for swinging up and balancing the pendulum of the RIPS. In simulations performed in the study, a pendulum is initially inclined at $45^{\circ}$ with respect to the upright position. A simulation is also performed for evaluating the adaptiveness of the designed BELBIC in the case of system variation. In addition, a simulation is performed for evaluating the robustness of the designed BELBIC against a disturbance in the control input.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.1
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• pp.10-14
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• 2013

High precision machining technology has become one of the important parts in the development of a precision machine. Such a machine requires high precision positioning as well as high speed on a large workspace. For machining systems having a high precision positioning with a long stroke, it is necessary to examine the repeatability of reference position decision. Though ball-screw driven linear stages equipped linear scale have high precision feed drivers and a long stroke, they have some limitations for reference position decision if they have not equipped the accurate home sensor. This study is performed to experimentally examine the repeatability for home position decision of a magnetic sensor as a home switch of ball-screw driven linear stage by using capacitance probe.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.2
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• pp.157-161
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• 2015

For machining systems having a high precision positioning with a long stroke, it is necessary to examine the repeatability of reference position decisions. Though ball-screw driven linear stages equipped with encoders have high precision feed drivers and a long stroke, they have some limitations for reference position decisions if they have not been equipped accurate home sensors. High precision machining technology has become one of the most important aspects of the development of a precision machine. Such a machine requires high precision positioning as well as high speed on a large workspace. This study is performed to experimentally compare the repeatability for home position decisions in the case of photo sensors and hall sensors as a home switch of the ball-screw driven linear stage.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.2
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• pp.152-158
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• 2003

A machine-vision guided inspection system with go-no gauges for inspecting eggcrate assemblies in steam generators is considered. To locate the gauge at the right place, periodic corrective actions for its position and traveling direction are required. We present a machine vision algorithm for determining inserting position and traveling direction of the go-no gauge. The overall procedure of the algorithm is composed of camera calibration, eggcrate image preprocessing, grid-height adjustment, intersection point estimation between two intersecting grids, and adjustment of position and traveling direction of the gauge. The intersection point estimation is performed by using linear regression with a constraint. A test with a real eggcrate specimen shows the feasibility of the algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.107.5-107
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• 2001

In this report, as the active position measurement system, a new method for two-dimensional position measurement system using a concept of semi-open type signal field has proposed. The feature of this system is realizing a position measurement only by scanning the encoded laser beams from scanning points to a measurement field, and observed it. First, both system configuration and encoding method are considered concretely, and M-sequence signal is selected for encoding. Next system design is performed to realize the theoretical measurement accuracy, and applied to a position measurement experiments. Experimental results show that measurement precision is larger than theoretical values. Furthermore, method for improving the measurement ...

• 한국전산유체공학회:학술대회논문집
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• 2004.10a
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• pp.131-136
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• 2004

Thermal control of satellite propellant tank is achieved by patch heaters enabled by thermostat's behavior. It is important to attach the thermostat on the appropriate position of the propellant tank. However its position cannot be given with exact numerics because tank is spherical. Actually the position for thermostat is designated in relevant drawing approximately, therby, the engineer practices depending on his own experience and intuition. The sensitivity analysis for the position of thermostat is performed such that the influence on the thermal behavior and control of tank is examined quantatively. When assembling tank module, the reasonable performance on the thermal control is believed with possible human errors if the uncertainty in the position of thermostat is not quite large.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.4
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• pp.463-467
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• 2014

High precision machining technology has become one of the most important parts in the development of a precision machine. Such a machine requires high precision positioning as well as high speed on a large workspace. For machining systems having high precision positioning with a long stroke, it is necessary to examine the repeatability of the reference position decision. Though ball-screw driven linear stages equipped with linear scale have high precision feed drivers and a long stroke, they have some limitations for reference position decisions if they have not been equipped with an accurate home sensor. This study is performed to experimentally examine the repeatability for home position decision of a photo micro sensor as a home switch of a ball-screw driven linear stage by using a capacitance probe.