• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.9
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• pp.799-807
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• 2017

In this paper, a new method is proposed for estimating pedestrians' walking velocity based on lower-limb kinematics and wearable inertial measurement unit (IMU) sensors. While the soles and ground are not in contact during the walking cycle, the walking velocity can be estimated by integrating the acceleration output of the inertial sensor mounted on the pelvis. To minimize the effects of acceleration measurement errors caused by the tilt of the pelvis while walking, the estimated walking velocity based on lower-limb kinematics is imposed as the initial value in the acceleration signal integration process of the pelvis inertial sensor. In the experiment involving outdoor walking for six minutes, sensor drift due to error accumulation was not observed, and the RMS error in the walking velocity estimation was less than 0.08 m/s.

• Journal of Sensor Science and Technology
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• v.5 no.1
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• pp.43-50
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• 1996

This paper presents a manufacture of the multiple subjects biotelemetry system using custom CMOS IC fabricated $1.5{\mu}m$ n-well process technology. The implantable circuits of the system except sensor interface circuits including FM transmitter are fabricated on a single chip with the sire of $4{\times}4mm^{2}$. It is possible to assemble the implantable system in a hybrid package as small as $3{\times}3{\times}2.5cm$ by using this chip, It's main function is to enable continuous measurement simultaneously up to 7-channel physiological signals from the selected one among 8 subjects. Another features of this system are to enable continuous measurement of physiological signals, and to accomplish ON/OFF switching of an implanted battery by subject selection signal with command signal from the external circuit. If this system is coupled with another appropriate sensors in medical field, various physiological parameters such as pressure, pH and temperature are to be measured effectively in the near future.

• Journal of Acupuncture Research
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• v.33 no.4
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• pp.93-100
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• 2016

Objectives : To find an acupuncture point where more exact Surface Electromyography(SEMG) measurement can be drown, through the study of measurement of orbicularis oris. Methods : Of healthy people from 19 to 40 years of age, who did not fall under exclusion criteria (22 males and 22 females), were selected as subjects, after relaxation for 10 minutes, and they were told how to pronounce 'O' and 'U' with their lips puckered. The SEMG figures were measured with attaching disposable electrode on acupuncture point of right-and-left Hwaryo(LI19) and 1 cun away from Seungjang(CV24) on both sides when the subjects pronounced 'O' and 'U'. Results : The average value was highest on left 1 cun away from Seungjang(CV24) in pronouncing 'O' and 'U', and the average SEMG value was higher in the order of right 1 cun away from Seungjang(CV24), right Hwaryo(LI19), left Hwaryo(LI19). Average of the lower orbicularis oris is statistically higher than that of the upper orbicularis oris, which has significant meaning. However, there was no significant difference when compared by pronunciation. Average of percentage mark of differences of right-and-left measured value of each pronunciation and each acupuncture point : Pronounced 'O' and the upper part of orbicularis oris: $16.76{\pm}11.29%$, pronounced 'O' and the lower part of orbicularis oris: $22.41{\pm}12.92%$, pronounced 'U' and the upper part of orbicularis oris: $17.10{\pm}9.89%$, pronounced 'U' and the lower part of orbicularis oris : $19.20{\pm}10.82%$. Conclusion : The difference of pronunciation will not affect the results in SEMG measurement. In addition, the average of the lower orbicularis oris is statistically and significantly higher than that of the upper orbicularis oris.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.3
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• pp.219-225
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• 2020

With the aging population, the prevalence of musculoskeletal disorders in the elderly continues to increase. In addition, musculoskeletal disorders are the third most common social and economic loss among occupational illnesses in Workers' compensation insurance benefits as of 2015 standard and are also common among workers. In this study, a vest that can assist in the prevention and treatment of musculoskeletal disorders of the waist was produced, and it is intended to confirm the presence or absence of the effect through experiments. Diseases of the waist are closely related to core muscles. Therefore, the produced vest was made in a form that supports the core muscles. Before and after wearing the vest for effectiveness verification, the While performing 10-times of the Mackenzie exercises, a waist extension exercise, collected the EMG data of the internal oblique, Rectus abdominis, and Erector spinae, which correspond to the core muscles. The collected data were analyzed through the electromyography analysis program RM-3 to obtain RMS values for 10-times measurements of each muscle and to compare the average values. After comparing the data, to verify the significance, the technical statistical value of the measurement result was calculated and the average difference was verified through PASW ver18.0, And the paired t-test is performed on the experimental results to perform statistical processing. and Statistical processing was performed by setting the significance level to α=.05.

• Journal of the Korean Institute of Navigation
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• v.20 no.4
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• pp.81-98
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• 1996

The purpose of this study was analysis of the muscle action in physical exercise in the rolling machine. The rolling machine moved by eletric power-driven was made to keep the constant cycle and size of rolling. The subjects of this study consist of 4 seaman(SM) and 4 landman (LM). The experiment analyzed the muscle power of lower and upper limbs by Intergrated Electromyogram(IEMG). The measurement was made on the ground, and 6 and 8 degrees of rolling separately. This study concludes as follows ; including analysis of IEMG of heavy exercise in two hands curl, a standstill walking and just standing. 1. IEMG of the lower limbs when standing. 1) In 6 degrees of rolling, for the landman(LM), vastus medialis m.(9.73), vastus lateralis m.(9.55), and rectus femores m.(8.73) acted more. As for the seaman(SM), tibialis anterior m.(5.38), biceps femores m.(5.05), and gastrocnemius m.(4.47) acted more. 2) In 8 degrees of rolling, in common, for both LM and SM, it were vastus medialis m.(11.20 and 8.97), vastus lateralis m.(16.20 and 4.63), and tibialis anterior m.(5.13 and 4.47). 3) It was showed that IEMG of LM was larger than that of SM. 2. IEMG of the lower limbs when walking. 1) On the ground, for the LM, gastrocnemius m.(7.08), vastus medialis m.(6.65), and vastus latralis m.(6.60) acted more. As for the SM, vastus lateralis m.(7.08), vastus medialis m.(6.58) and restus femores m.(5.10) acted more. 2) In both 8 and 6 degrees of rolling, vastus medials m.(14.50 and 11.98), vastus lateralis m.(10.10 and 14.10), and gastrocnemius m.(11.75 and 7.10) acted more in two groups. 3) It was showed that IEMG of LM was larger than that of SM. 3. IEMG of the lower limbs when heavy exercise(two hands curl). 1) On the ground, for the LM, vastus lateralis m.(21.68), vastus medialis m.(16.08), and rectus femores m.(14.08) acted more. As for the SM, tibialis anterior m.(16.08), vastus medialis m.(14.58), and vastus lateralis m.(8.78) acted more. 2) In 8 and 6 dgrees of rolling, it were vastus medialis m.(17.05 and 12.45), vastus lateralis m.(37.98 and 17.08), and tibialis anterior m.(19.83 and 13.20). 3) It was showed that IEMG of LM was larger than that of SM. 4. IEMG of the upper limbs when heavy exercise. 1) On the ground, the brachialis m.(44.30 and 17.80), and biceps brachii m.(13.40 and 25.10) acted more in two groups. 2) In both 6 and 8 degrees of rolling, the brachialis m.(37.60 and 24.35), and biceps brachii m.(11.38 and 7.97) acted more in two groups. 3) It was showed that IEMG of SM was larger than that of LM.

• Journal of Korea Entertainment Industry Association
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• v.14 no.3
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• pp.475-482
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• 2020

The abdominal drawing-in maneuver(ADIM), which is performed to strengthen the stabilization muscles of the lumbar, is an exercise method that selectively contracts the TrA and IO by increasing intra-abdominal pressure. In order to check the effect of ADIM in sitting position, which is the most frequently used posture in everyday life, on how to grip power, ADIM was conducted in a sitting position for 30 healthy adults, and then the state was not performed. In each, the grip power was measured to determine how ADIM performed in the sitting position had an effect on grip power and which muscles had the most influence. The muscles mobilized for the electromyography(EMG) measurement were RA, EO, IO/TrA, and ES, which were the most activation lumbar stabilization muscles when ADIM was applied. As a result of the study, the activity on muscles of the lumbar stabilization was significantly increased and the grip power of the muscles was significantly increased than the ADIM in the sitting position. By comparing the measured difference value of each muscle, it was found that any muscle had a greater effect on grip power, but no muscle showed a significant correlation. It is thought that the increase of intra-abdominal pressure did not affect the grip power of a specific muscle. Therefore, if ADIM is performed in a sitting position that is frequently used in everyday life through this study, it will be more effective in increasing the grip power and lumbar stabilization.

• The Korean Journal of Physiology
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• v.18 no.1
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• pp.67-79
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• 1984

In an effort to elucidate the physiological characteristics in cardiopulmonary function, electromyogram(EMG), and blood chemistry in athletic high school students, an analysis of electrocardiogram(ECG) and EMG, pulmonary function test, venous blood gas analysis($Pvo_2$ and$Pvco_2$), and measurement of heart rate, blood pressure, respiratory rate, blood glucose and blood lactate were made for 16 to 19 year-old high school students who were divided into athletic (n=19) and non-athletic (n=20) group. The results obtained are summarized as follows. 1) ECG intervals in athletes were longer than in non-athletes, and the difference was significant in R-R, Q-T and T-P intervals. Resting heart rate in athletes was 56.3/min showing a bradycardia compared with 79.8/min in non-athletes. Amplitudes of R and T waves in lead $V_5$ were significantly higher than in non-athletes. 2) Pulmonary function parameters in athletes showed higher values than in non-athletes. Parameters which showed significant differences were FEV 0.5, PEF, FEF 25%, PIF and FEF $200{\sim}1.200\;ml. 3) Heart rate, blood pressure, and respiratory rate after exercise were significantly elevated from resting values. Heart rate and respiratory rate showed greater increase in non-athletes, while blood pressure showed greater increase in athletes. 4) $Pvo_2$ was lowered ana $Pvco_2$ was elevated after exercise, and there was no significant difference between two groups. 5) Blood glucose and lactate levels were elevated after exercise. The difference was significant in blood lactate, and was greater in non-athletes. 6) EMG amplitude was steadily increased with increasing load of exercise, and the increase was greater in athletes than in non-athletes.

• Korean Journal of Applied Biomechanics
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• v.25 no.4
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• pp.383-391
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• 2015

Objective : The purpose of this study was to investigate the effects of dynamic squats with slope-whole body vibration (WBV) on the trunk and lower limb in muscle activities. Method : 9 healthy women (age: $21.1{\pm}0.6years$, height: $160.5{\pm}1.4cm$, body weight: $50.5{\pm}2.4kg$) were recruited for this study. Muscle activities in the trunk and lower limb muscles, including biceps femoris (BF), rectus femoris (RF), rectus abdominum (RA), gastrocnemius (GCM), iliocostalis lumborum (IL) and tibialis anterior (TA), were recorded using an EMG measurement system. The test was performed by conducting dynamic squats with slope-WBV using frequency (10Hz, 50Hz), amplitude (0.5mm), and degree ($0^{\circ}$, $5^{\circ}$). Experimental method consisted of 2-pre-sessions and 1-test-session for 20 seconds. Results : The results showed that the muscle activities of the trunk and low limb muscles increased significantly with the $5^{\circ}$ slope and lower frequency (10Hz) except for in the TA. From this result, we confirmed that the slope and WBV could efficiently affect stimulation, enhancing muscle activities by facilitating neural control trail and muscle chain tightness. Conclusion : Utilizing the slope-WBV device while squatting could give positive effects on muscle activation in the trunk and lower limb muscles and provide neural stimulation, enhancing muscle chain of control subsystem through TVR (tonic vibration reflex).

• Journal of the Korean Society of Physical Medicine
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• v.11 no.3
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• pp.65-72
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• 2016

PURPOSE: The purpose of this study is to determine the differences between the muscle activity of cranio-cervical flexion and extension muscles according to the types of tools used through a short-term intervention of cranio-cervical static stabilization exercises using small tools. METHODS: A total of fifteen male and female adults in their 20s who showed forward head posture in the overall body posture measurement system participated in this study. Each subject performed cranio-cervical static stabilization exercises about flexion and extension while using a sling, a foam roller, a TOGU ball, and without tools separately, and the muscle activity of the sternocleidomastoid muscle, scalenus anterior and splenius capitis was measured. Each value was measured for 10 seconds a total of three times. The maximum voluntary isometric contraction value was computed using the average during the middle four seconds. RESULTS: Cranio-cervical flexion exercises using various tool types, the average activity of the sternocleidomastoid and scalenus anterior muscles was significantly higher when applying the TOGU ball (p<.05). According to the results of implementing cranio-cervical flexion exercise using various tools, the maximum muscle activity of the sternocleidomastoid muscle was significantly higher for the TOGU ball (p<.05). CONCLUSION: Based on these results, the provision of an unstable surface using small tools rather than a stable surface is recommended as an exercise scheme for proprioceptive stimulation in a forward head posture. Particularly, we recommend using the TOGU ball for the provision of an unstable surface to increase the muscle activity of the sternocleidomastoid muscle and scalenus anterior.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.5 no.2
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• pp.11-21
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• 2007

The purpose of this study were to investigate influence of heat stress temperature on sympathetic nerve activities. Subjects were 8 normal adults (4 men, 4 women, 21.36 years old). First sympathetic nerve activities were measured at the point that increase of core temperature stops at the state of applying normal thermic temperature (NIT; $34^{\circ}C$). After measurement, temperature of bathtub was increased to heat stress temperature (HST; $46^{\circ}C$) and sympathetic nerve activities were remeasured at the point that temperature increase stops. Sympathetic skin response (SSR) were analyzed using EMG, IR thermometer, and auto stethoscope. SSR latency showed significant differences at both palms by electrical stimulation to median nerve (p<.05). Electrical stimulation to forehead showed significant difference at left palm (p<.05) and electrical stimulation to navel showed significant difference at right palm (p<.05). Median nerve in changes of SSR amplitude showed significant differences at both palms in HST (p<.01). Electrical stimulation to navel showed significant difference at left palm (p<.05). Ts of forehead and xiphoid process showed significant differences (p<0.01). Tc of oral (p<0.05) and inner ear (p<0.01) showed significant differences. Pulse rate showed significant difference (<0.05). This study showed that immersion in HST had significant decrease of excitability in sympathetic nervous system compared to immersion in NTT.