• Proceedings of the ESK Conference
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• 1997.04a
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• pp.10-16
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• 1997

The ride comfort is one of the most important indices which decide the quality of automotive seats. A subjective evaluation is the general method for comfort evaluation of automotive seats. But the subjective evaluation assess the individual sensibility using questionnaire. Therefore, a need to develop methodologies to obtain objective measurements of the fatigue evaluation is evident. In an effort to monitor muscle activity during driving electromyography (EMG) was employed. In an experimental setting the subjective evaluation was conducted using questionnaire under the static conditions (8 subjects) and the fatigue was induced in muscles using EMG under the dynamic conditions (2 drivers). The resultant EMG signals were then sampled for three different muscles. In test involving 2 subjects of similar size and build, utilizing four different automotive seats, test results support the use of EMG to quantify muscular fatigue as a viable means of objective evaluation for the different automotive seats.

• Journal of Biomedical Engineering Research
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• v.32 no.4
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• pp.319-327
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• 2011

Skeletal muscle fatigue is defined as a 'any reduction in the maximal capacity to generate force or power output', and is the reduction of oxygen consumption and by-product of metabolism. For the muscle fatigue therapy, low level laser has been introduced that leads the mitochondrial respiratory and attributes the muscle fatigue recovery. This study analyzed the muscle fatigue signals from electromyography(EMG) during low-level laser therapy (LLLT). Healthy subjects performed voluntary elbow flexion-extension excercise and received placebo LLLT and active LLLT using a 830 nm laser diode. Then, EMG were measured for the evaluation of muscle fatigue. The acquired EMG data were analyzed with median frequency and short time fourier transform methods. The results showed that the LLLT had a significant symptomatic relief of muscle fatigue based on the EMG frequency analysis. Therefore, the muscle fatigue analysis with EMG signals can be applied to quantitative evaluation for the monitoring of LLLT effects.

• Proceedings of the ESK Conference
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• 1997.10a
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• pp.433-436
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• 1997

Automobile assembly tasks consist of many kinds of manual work which are very stressful to workers because of repetitive poor working postures and dealing heavy weights. To decrease the level of workload, it is necessary to evaluate the workload quantitatively. In this study, a workload evaluation method based on EMG was experimentally evaluated. We measured EMG at 6 main muscles with 2 healthy male workers during doing 9 assembly tasks, which were selected as high workload jobs. The tasks were decomposed into 36 elementary tasks. The workload was calculated through an equation with %MVIS and work duration time. To evaluate the result, subjective discomfort on the tasks was assessed by 29 workers. By the calculated workload, we were able to ranked the workload of tasks, elementary tasks. The comparison between the EMG-based workload and subjective rating showed a positive correlation(P-value=0.0246). We think it is possible to adapt the EMG-based workload evaluation technique to all assembly tasks by expending the experi- ment size.

• Journal of Biomedical Engineering Research
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• v.17 no.2
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• pp.155-164
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• 1996

In the clinical environment, measurements of some characteristics of the skeletal muscle are currently used to assess the severity of a neuromuscular disease or in some cases to assist in making a diagnosis. But a quantitative method of evaluation has not yet been introduced satisfactorily. In this paper, the skeletal EMG(biceps muscle, masseter muscle) analysis has been processed both in the time and in the frequency domain by designing the digital signal processing system based on pentium PC and transputer (IMS 7805). The experiment have been performed in five normal subjects, and various parameters have been statistically tested and compare4 As a results, the effective parameters obtained for the evaluation of skeletal EMG electrical activity are turn analysis, MiTi, MiTa, IEMG, PDF in the time domain, and are mean frequency, median frequency, skewness, kurtosis, muscle fatigue slope in the frequency domain. The designed H/W and S/W in this study can be used effectively for the establishment of EMG data base and for clinical research.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.5
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• pp.338-347
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• 2005

A computer-based low back muscle evaluation system was designed to simultaneously acquire, process, display, quantify, and correlate electromyographic(EMG) activity with muscle force, and range of motion(ROM) in the lumbar muscle of human. This integrated multi-channel system was designed around notebook PC. Each channel consisted of a time and frequency domain block, and T-F(time-frequency) domain block. The captured data in each channel was used to display and Quantify : raw EMG, histogram, zero crossing, turn, RMS(root mean square), variance, mean, power spectrum, median frequency, mean frequency, wavelet transform, Wigner-Ville distribution, Choi-Williams distribution, and Cohen-Posch distribution. To evaluate the performance of the designed system, the static and dynamic contraction experiments from lumbar(waist) level of human were done. The experiment performed in five subjects, and various parameters were tested and compared. This system could equally well be modified to allow acquisition, processing, and analysis of EMG signals in other studies and applications.

• Fashion & Textile Research Journal
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• v.25 no.2
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• pp.210-220
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• 2023

Recently, smart wearable products, including electromyography (EMG) measurement devices and clothing, have been developed to monitor users' exercise levels, muscle activation, and muscle balance more effectively during fitness activities. However, technical and socioeconomic barriers, such as flexibility and durability, still pose challenges in terms of comfort, ease of wear, and wearability of smart clothing, which includes devices and circuits. To address these issues, this study developed a wearable EMG device integrated with clothing to collect valid EMG signals from desired muscles while maintaining comfort, functionality, and ease of wear. After deriving a combined structure that could stably position the wearable device within the clothing, a prototype was manufactured and evaluated for fit, compression, comfort, and exercise comfort test by ten participants (height = 176.2 cm, weight = 76.4 kg, chest circumference = 101.2 cm). The study found that the prototype had smaller circumferences around the chest, waist, and abdomen compared to commercial products, resulting in lower ratings for wearing comfort and ease of wear. However, the prototype received high ratings for fitting, pressure, and the exercise comfort test. Valid signals were obtained when the EMG device was combined to the prototype for the rectus femoris muscle, indicating stable positioning of the device during exercise.

• Journal of the Korean Society of Clothing and Textiles
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• v.48 no.1
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• pp.94-107
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• 2024

This study developed compression pants with excellent wearability and signal quality by approaching the design of wireless sEMG monitoring pants from the perspective of technical design, including the evaluation of wearability and the stable wireless transmission of signals through electrode and circuit design, and using e-textiles. An electrode, sewn with silver thread and a circuit stitched in a zigzag pattern using stainless steel wire, were applied. Additionally, polyurethane sealing tape was used to enhance adherence to the skin and reduce electrical resistance. Conductive snaps completed the design, allowing attachment and detachment to the bio-signal acquisition mainboard. Through the subjects' evaluation, it was determined that the final pants were applied with a pattern reduction rate of 25% to provide superior comfort according to different body parts while also minimizing skin irritation around the thigh circuit. The final pants for wireless sEMG monitoring, which demonstrated stable transmission of wireless measurements, was positively evaluated in terms of cognitive acceptability. This study is significant in that it achieved an optimal design by considering both technical aspects and the electrical characteristics of bio-signal monitoring garments, as well as the wearer's perception when designing smart wear.

• Journal of the Korean Society of Safety
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• v.27 no.1
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• pp.111-116
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• 2012

Workers who work with his neck bent backward in the standing posture have often complained of their musculoskeletal stress. The objective of this study was to find how much stress there was for workers who worked with their neck bent backward. The subjective evaluation and electromyography(EMG) were used to check the level of the stress. It was found that all subjects felt extreme pain after working with the neck bent backward and alternating 1 minute work and 0.5 minute rest for 30 minutes. The EMG level(amplitude) of neck muscles increased 80 percent on the average and the center frequency of EMG shifted to the lower frequency level which indicated fatigue of neck muscles. Thus, the intervention of this musculoskeletal stress is strongly recommended.

• Journal of Biomedical Engineering Research
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• v.32 no.4
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• pp.328-335
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• 2011

For human factor engineering and wearable robot design, the quantitative assessment of physical workload is needed. Through measuring the surface EMG (sEMG) and analysis, the physical workload in overhead lifting posture is presented in quantitative manner. By normalizing sEMG activities with maximal voluntary contraction (MVC), the inter-subject variability is reduced. In all muscles, %MVC increased as the weight of lifting object increases. In anterior deltoid muscle, the %MVC was 3-4 times higher than the other muscles which imply that this muscle performs the major role in the overhead lifting posture. In fatigue analysis, %MVC and the mean frequency in muscle of anterior deltoid changed markedly when compared with other muscles. Through the suggested procedures and analysis, the physical workload for a specific posture can be represented in quantitative way but the clinical meaning for the value should be investigated further.

• Journal of Oral Medicine and Pain
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• v.46 no.4
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• pp.143-149
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• 2021

Purpose: Oromandibular dystonia is a neurological disorder that affects the jaw and lower face muscles, often resulting in abnormal repetitive movement of the jaw and perioral structures. The purpose of this study was to assess the effectiveness of surface electromyography (EMG) in evaluating the treatment outcome of oromandibular dystonia. Methods: Based on a retrospective review of medical records, we analyzed the data of four patients who received medication or botulinum toxin injection, as well as surface EMG of the jaw muscles before and after treatment. We assessed the patients' clinical characteristics and the results of surface EMG before and after treatment. Results: The case series included one female and three males, and the age range was 65-78 years. Based on the clinical features, two subjects were classified as jaw deviation and the remaining two were as jaw closing. Dystonic patterns revealed by surface EMG varied, including phasic, tonic, and mixed contraction patterns. EMG amplitude after treatment was lower than pre-treatment value in all four subjects, suggesting improved clinical signs and symptoms. One subject who received clonazepam and another who received botulinum toxin injection showed a remarkable reduction in EMG amplitude within a normal range. Conclusions: Surface EMG can be used to effective evaluate treatment outcomes in patients with oromandibular dystonia. It could be considered as an adjunctive diagnostic tool in managing patients with dystonia.