• Journal of Biomedical Engineering Research
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• v.32 no.2
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• pp.144-150
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• 2011

The primary purpose of this study was to analyze the motion of the scaphoid, capitate, and lunate during dart-throwing motion by three-dimensional modeling. Five series of CT images of five normal right wrists were acquired from five motion steps from radial extension to ulnar flexion in the dart-throwing motion plane. Segmentation and three-dimensional modeling of bones from CT images was performed using Analyze. Distances among centroids of the scaphoid, capitate and lunate and angles between principal axes of three carpal bones were calculated to analyze the motion by using MATLAB. As the wrist motion changed from radial extension to ulnar flexion, the distance between two adjacent bones decreased. The scaphoid and lunate rotated less than the capitates during dart-throwing motion. This study reports the Three-dimensional in vivo measurement of carpal motion using CT images.

• Journal of Biomedical Engineering Research
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• v.40 no.6
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• pp.242-249
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• 2019

Forearm electromyography (EMG) generated by wrist movements has been widely used to develop an electrical prosthetic hand, but EMG generated by finger movements has been rarely used even though 20% of amputees lose fingers. The goal of this study is to improve the classification performance of different finger movements using a deep learning algorithm, and thereby contributing to the development of a high-performance finger-based prosthetic hand. Ten participants took part in this study, and they performed seven different finger movements forty times each (thumb, index, middle, ring, little, fist and rest) during which EMG was measured from the back of the right hand using four bipolar electrodes. We extracted mean absolute value (MAV), root mean square (RMS), and mean (MEAN) from the measured EMGs for each trial as features, and a 5x5-fold cross-validation was performed to estimate the classification performance of seven different finger movements. A long short-term memory (LSTM) model was used as a classifier, and linear discriminant analysis (LDA) that is a widely used classifier in previous studies was also used for comparison. The best performance of the LSTM model (sensitivity: 91.46 ± 6.72%; specificity: 91.27 ± 4.18%; accuracy: 91.26 ± 4.09%) significantly outperformed that of LDA (sensitivity: 84.55 ± 9.61%; specificity: 84.02 ± 6.00%; accuracy: 84.00 ± 5.87%). Our result demonstrates the feasibility of a deep learning algorithm (LSTM) to improve the performance of classifying different finger movements using EMG.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.5 no.3
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• pp.144-151
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• 2012

Chronic gastritis is the disease that is occuring in one in every 10 persons in Korea. In western medicine, endoscopy is needed to diagnose chronic gastritis, but it causes patients a pain and budget of expense. According to the TEM (Traditional Eastern Medicine), on the other hand, the 'Guan' position of the right wrist is related to a stomach. Thus we can diagnosis chronic gastritis by analyzing of pulse signal. However, pulse signal diagnosis is depended on oriental doctor's knowledge and experience. In this study, a systematic approach is proposed to analyze the computerized pulse signal. The pulse signals are firstly pre-processed, Gaussian model is adopted to fit the pulse signal, and then some related parameters are extracted from the model. Consequently, disease-sensitive parameters are selected by T-test and statistical difference. Finally, the selected parameters are entered into a Fuzzy C-Means (FCM) algorithm for classification. Classification results show that healthy persons and chronic gastritis patients are 95% and 87%, respectively.

• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.381-386
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• 2010

This study examined the changes in the walking pattern during level walking under low illumination conditions. Fourteen male subjects ($22.1{\pm}2.21$ years, $174{\pm}3.74\;cm$, $68.86{\pm}10.81\;kg$) with normal vision and no disabilities were enrolled in this study. All experiments were performed on a level walkway with three conditions: normal walking (preferred & low speed) and walking with low illumination. 3D motion capturing system was used for acquisition and analysis of the walking motion data with a sampling frequency of 120Hz. The walking speed, normalized jerk(NJ) at the center of mass(COM), wrist and heel, knee and elbow joint angle, ratio of the knee joint angle to elbow joint angle and the toe clearance on stance phase were used to compare the differences in walking pattern between the two illumination conditions, The results showed that the walking speed and joint angles decreased in low illumination, whereas the NJ and toe minimum clearance increased. In low illumination, most variables were similar to effects of low speed walking, but toe clearance was different from the effects of low speed. These results can be used as primary data for examining the changes in the level walking pattern of young adults under low illumination. Further study will be needed to compare these results in young adults with those in the elderly.

• Korean Journal of Applied Biomechanics
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• v.28 no.1
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• pp.55-60
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• 2018

Objective: This study aimed to analyze the effects of computer game exposure on pathological musculoskeletal symptoms in adolescents. Method: This study included 10 male junior high school students who used computers less than 3 times a week for 1 hr per day. The subjects were asked to play computer games for 4 hr. Magnetic resonance imaging of the hand and wrist, from the distal radius and ulnar head to the distal phalanges, and radiography of the cervical vertebrae were performed before and after playing computer games. For each dependent variable, a paired t-test was performed to identify significant changes before and after a 4-hr active computer game (p<.05). Results: The horizontal diameters of the flexor tendons in the index and middle fingers were significantly reduced after playing computer games. The horizontal diameters of the flexor tendons of other fingers did not show any significant differences, but there was a tendency toward a decrease after playing computer games. There was no significant change in the cervical lordosis angle before and after playing computer games. However, the cervical lordosis angle was relatively decreased. Conclusion: The results of this study showed that computer game exposure had direct and indirect effects on morphological changes of flexor tendons. In addition, playing computer games for long periods of time can have a negative effect on normal functioning of the musculoskeletal system, with the possible development of abnormalities. However, computer game exposure in adolescents cannot be decisively identified as a factor causing pathological symptoms, based on the results of this study alone. Thus, longterm longitudinal studies on the overall musculoskeletal system are necessary.

• Archives of Plastic Surgery
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• v.34 no.4
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• pp.471-477
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• 2007

Purpose: Hydrofluoric acid(HF) is one of the most dangerous mineral acids with dissociated fluoride ions. As hydrofluoric acid is present in various household products(such as rust removers), a large population of industrials is at the risk of HF exposure. It is a very strong organic acid, used widely in glass etching, metal washing, and in the semiconductor industry. Even when using adequate safety measures, lack of care on the user's part results in chemical burn by HF. Symptoms caused by HF-induced chemical burns shows delayed manifestations resulting in a loss of proper treatment opportunities. We therefore reviewed 20 cases of HF-induced chemical burns and treatment principle. Methods: The objects of this study were 19 male patients and 1 female treated from March 2004 to March 2006. There were 19 cases of injury on digits and 1 on the wrist area. There were 15 cases of immediate treatment after sustaining HF-induced burns, and 5 cases of delayed treatment. As a principle, in the emergency treatment, partial or complete removal of the nail along with copious washing with normal saline was done, depending on the degree of HF invasion of the distal digital extremities. Results: The 15 cases who came to the hospital immediately after the injury were healed completely without sequelae, and those who delayed their treatment needed secondary surgical measures, due to the severity of inflammation and necrosis of the digital tissues. Conclusion: As the industrial sector develops, the use of HF is increasing more and more, leading to increase in incidences of HF-induced chemical burns. When treating chemical burns caused by HF, washing by copious amounts of normal saline, along with early removal of the nails, rather than calcium gluconate, seems to be a available method for preserving the shape and function of the digits and the nail. The education of patients regarding this subject should be empathized accordingly.

• The Journal of Korean Physical Therapy
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• v.28 no.1
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• pp.39-45
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• 2016

Purpose: Physical therapists are likely to be exposed to work-related musculoskeletal pain due to excessive repetitive tasks. This study was conducted to identify the relationship between work-related musculoskeletal pain and quality of life of physical therapists. Methods: A self-reported questionnaires was sent to 200 physical therapists at in Seoul and Kyoungido. The questionnaires was returned by 170 physical therapists. The questionnaire had included 4 items that coveringed demographic information, areas of musculoskeletal problems, pain rating scale, and WHOQOL-BREF. The analysis was completed using descriptive statistics, and differences between pain and demographic variables were identified using the chi-square test. The relationship between work-related musculoskeletal pain and quality of life was analyzed by t-test and Pearson's correlation. Results: The overall prevalence of work-related musculoskeletal pain was 76.8%. The most affected pain sites included the low back (48.8%), shoulder (45.,2%), hand and wrist (43.5%), and neck (33.3%). Pain ratings of subjects with pain was were moderate. There was a A significant difference for the subdomains of quality of life was observed between the subjects with musculoskeletal pain and those without pain. Weak negative correlations (r=-0.28) were observed between pain rating scale and QOL. Conclusion: These findings show that physical therapists appear to be at a higher risk for work-related musculoskeletal pain and physical domain of QOL. Therefore, Ffurther research is needed to investigate examine the effect of risk factors and ergonomics as physical load, general health status on prevalence of musculoskeletal pain.

• The Journal of Korean Physical Therapy
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• v.23 no.1
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• pp.77-82
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• 2011

Purpose: Recently, many studies have demonstrated that application of external stimulation can modulate cortical excitability of the human brain. We attempted to observe cortical excitability using functional magnetic resonance imaging (fMRI) during the application of transcranial direct current stimulation (tDCS) or functional electrical stimulation (FES). Methods: We recruited two healthy subjects without a history of neurological or psychiatric problems. fMRI scanning was done during? each constant anodal tDCS and FES session, and each session was repeated three times. The tDCS session consisted of three successive phases (resting phase: 60sec dummy cycle: 10sec tDCS phase: 60sec). The FES session involved stimulation of wrist extensor muscles over two successive phase (resting phase: 15sec FES phase: 15sec). Results: The average map of the tDCS and FES analyses showed that the primary sensory-motor cortex area was activated in all subjects. Conclusion: Our findings show that cortical activation can be induced by constant anodal tDCS and FES. They suggest that the above stimuli have the potential for facilitating brain plasticity and modulating neural excitability if applied as specific therapeutic interventions for brain injured patients.

• Journal of Trauma and Injury
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• v.27 no.3
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• pp.57-62
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• 2014

Purpose: A hamate body coronal fracture is well known as a very rare fracture in the carpal bones and is also hard to diagnose in initial stage due to the bone's architecture. We report our experience in treatment of such a fracture, and we present a review of the relevant literatures. Methods: Four patients who experienced hamate body coronal fractures from October 2006 to October 2013 were enrolled in this study. One patient also had an associated Capitate fracture, and two patients had associated dislocations of the $4^{th}$ metacarpal joint. We performed open reduction and mini-screw fixation on the four patients. In addition, a K-wire was fixed for the two patients with dislocations. Results: The average follow-up period was 24.5 months after surgery, and bone union was observed at the $8^{th}$ week after surgery. We confirmed that bone union had been completed for all the patients, and functional tests showed that joint motion was in the normal range without complications. Conclusion: When a patient has consistent pain on the ulnar side of the wrist, a hamate fracture should be suspected. Computer tomography is better than a simple X-ray scan for confirming the diagnosis of a hamate body coronal fracture. An open reduction and mini-screw fixation led to a good result.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.1071-1076
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• 2011

NC machines are generally used for machining operations because of their position accuracy, path accuracy, and machining reaction force. However, some NC machines require a very large space and are expensive. Recently, industrial articulated robot arms with large handling capability and wrist torque have been developed and the corresponding sensor technology has been improved. A machining robot for three-dimensional large curved objects was developed on the basis of an automatic-path-generation method. A self-position-compensation method with a laser displacement sensor was adopted for the six-axis robot developed, because the large articulated robot arms had poor position accuracy. An automatic-path-generation method using specific points was adopted to reduce the number of teaching points and time. In order to determine the proper machining conditions, various machining conditions such as tool rotation speed, cutting angle, cutting depth, and tool moving speed, were evaluated.