• 재활복지공학회논문지
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• 제7권2호
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• pp.69-74
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• 2013

본 연구에서는 손목 움직임의 추정을 위한 근전도 신호 기반 동작 분류 알고리즘을 제안한다. 근전도의 특징점을 추출하기 위하여 절대차분표준편차(DASDV)과 제곱평균제곱근(RMS)을 사용하며, 측정 된 근전도 신호를 이용하여 동작 마다 30개의 특징점(RMS, DASDV)을 추출한다. 근전도 신호를 특정한 패턴으로 나타내어 적용시키기 위하여 평균값을 기준으로 집단을 두 부분으로 나누고, 패턴분류 방법인 k-NN으로 패턴을 학습시킨 후, 집단을 나누지 않은 방법을 사용한 기존의 연구와 비교하여 제안한 알고리즘의 성능을 검증한다. 실험결과 제안한 알고리즘은 92.59%의 인식률을 보였으며, 이전 연구 결과보다 0.84% 포인트의 성능 개선을 보였다.

• 재활치료과학
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• 제3권1호
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• pp.39-45
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• 2014

목적 : 본 연구의 목적은 말초신경병증인 Guillain-Barre Syndrome 환자에게 근전도 유발 신경근 전기자극을 적용한 사례 연구를 통해 치료의 효과를 알아보는데 있다. 연구방법 : FMA와 JTHFT 결과 특히 손목과 손 기능이 저하되어있는 Guillain-Barre syndrome 환자에게 4주간, 하루 1회, 좌우 각각 30분씩, 손가락 폄근(extensor digitorum communis)에 근전도 유발 신경근 전기자극을 적용하였다. 결과 : 4주간 실시한 결과 FMA의 wrist, hand 에서 개선을 보였고, JTHFT의 일부 개선을 보였다. 결론 : 근전도 유발 신경근전기자극치료를 말초신경계 병증인 Guillain-Barre Syndrome 환자에게 적용하였을 때 적절한 치료 효과를 나타내었다.

• 인터넷정보학회논문지
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• 제18권3호
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• pp.11-17
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• 2017

To the elderly, sudden falls are one of the most frightening accidents. If an accident occurs, a prompt action has to be taken to deal with the situation. Recently, there have been a number of attempts to detect sudden falls using acceleration sensors embedded in the mobile devices, such as smart phones and wrist-bands. However, using the sensor readings only, the detection rate of the falls is around 65%. Ordinary daily activities such as running or jumping could not be well distinguished from the falls. In this paper, we describe our attempts on improving the fall-detection rate. We implemented a wrist-band fall detection module, using a three-axis acceleration sensor. With the pattern matching on the fall signal-strength frequency spectrum, in addition to the conventional signal strength measurement, we could improve the detection rate by 9% point. Furthermore, by applying two wrist-bands in the experiment, we could further improve the detection rate to 82%.

• 대한물리의학회지
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• 제5권4호
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• pp.685-692
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• 2010

Purpose : The purpose of this study was to investigate effects of repetitive hand task on upper extremity proprioception and dexterity. Methods : Experimental group who had done hand task since last 1 year and young adult control group was recruited this study. Proprioception was measured positioning errors of elbow and wrist on three dimensional coordinate system by Winarm software(Zebris Medcal GmbH, Germany). And dexterity was measured by box and block test. Statistical analysis was used independent t -test. Results : When elbow moved from flexion to extension, there were significant difference on error of x axis in wrist location and erros of x, z axis in shoulder location(p<.05). When wrist moved from flexion to extension, there was significant difference on y axis in finger location error(p<.05). And there significant difference on dexterity(p<.05). Conclusion : In conclusion, repetitive hand task increase upper extremity proprioception and dexterity. The physical therapy in industrial workers should inhibit overuse injury.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1303-1306
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• 2004

We developed a symmetrical upper limb motion trainer for chronic hemiparetic subjects. This trainer enabled the practice of a forearm pronatio $n^ination and wrist flexion/extension. In this study, we have used functional magnetic resonance imaging(fMRI) with the developed symmetrical upper limb motion device, to compare brain activation patterns elicited by flexion/extension wrist movements of control and hemiparetic subject group. In control group, contralateral somatosensory cortex(SMC) and bilateral cerebellum were activated by dominant hand movement(Task 1), while bilateral movements by dominant hand(Task 2) activated the SMC in both cerebral hemispheres and ipsilateral cerebellum. However, in hemiparetic subject group, contralateral supplymentary motor area(SMA) was activated by unaffected hand movement(Task 1), while the activation of bilateral movements by unaffected hand(Task 2) showed only SMA in the undamaged hemisphere. This study, demonstrating the ability to accurately measure activation in both sensory and motor cortex, is currently being extended to patients in clinical applications such as the recovery of motor function after stroke.ke.

• 한국안전학회지
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• 제14권4호
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• pp.168-175
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• 1999

The objective of this research is to review the ergonomic keyboard developed to prevent musculo-skeletal disorders from being occurred during keyboard work. It was studied by comparing it with the traditional keyboard after analyzing and comparing the typing performance and work advantages both the two keyboards. Twelve male subjects with no history of musculo-skeletal disorders participated in the experiment. The quantitative data such as typing speed, accuracy, performance time, and the number of typing errors were obtained from the HTT software that was adjusted for this experiment. RULA worksheet and the degrees of extension and ulnar deviation on right and left wrist were used to analyze the upper body postures. The experiment results showed that the typing performance of the ergonomic keyboard decreased a little, but no significant difference statistically, compared with that of the traditional keyboard. On the work posture, the ulnar deviation during typing decreased in case of the ergonomic keyboard. But, the wrist extension was increased unexpectedly. Therefore, it can be regarded as these results occur due to the shape of wrist rest and the overall height of keyboard on a table. As a result, the reconsideration and redesign on the ergonomic keyboard are requested.

• 로봇학회논문지
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• 제12권2호
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• pp.206-216
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• 2017

This paper proposes a method to simultaneously estimate two degrees of freedom in wrist forces (extension - flexion, adduction - abduction) and one degree of freedom in grasping forces using Electromyography (EMG) signals of the forearms. To correlate the EMG signals with the forces, we applied a multi - layer perceptron(MLP), which is a machine learning method, and used the characteristics of the muscles constituting the forearm to generate learning data. Through the experiments, the similarity between the MLP target value and the estimated value was investigated by applying the coefficient of determination ($R^2$) and root mean square error (RMSE) to evaluate the performance of the proposed method. As a result, the $R^2$ values with respect to the wrist flexion-extension, adduction - abduction and grasping forces were 0.79, 0.73 and 0.78 and RMSE were 0.12, 0.17, 0.13 respectively.

• 제어로봇시스템학회논문지
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• 제17권8호
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• pp.824-832
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• 2011

An essential consideration to differentiate prosthetic hand from robot hand is its convenience and usefulness rather than high resolution or multi-function of the robot hand. Therefore, this study proposes a myoelectric hand with a 2 DOF auto wrist module which has 6 essential functions of the human hand such as open, grasp, pronation, supination, extension, flexion, which improves the convenience of the daily life. It consists of the 3 main parts, the myoelectric sensor for input signal without additional attachment to operate the prosthetic hand, hand mechanism with high-torqued auto-transmission mechanism and self-locking module which guarantee the safety under the abrupt emergency and minimum power consumption, and dual threshold based controller to make easy for adopting the multi-DOF myoelectric hand. We prove the validity of the proposed system with experimental results.

• 대한소아치과학회지
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• 제41권1호
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• pp.27-33
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• 2014

소아 환자가 치과 진료실에서 느끼는 불안감과 공포에 의해 발생하는 스트레스를 측정하기 위한 다양한 방법이 있다. 치료받은 환아나 보호자를 통한 설문을 이용하는 방법과 생체 반응을 측정하는 방법이 가장 많이 사용되고 있다. 스트레스와 관련한 심박수를 측정하는 방법으로 가장 많이 사용하는 것은 포화도 측정기가 있으나 움직이는 소아에게는 적절하지 못한 문제가 있다. 이러한 단점을 극복하기 위해 최근 개발되어 소개된 손목형 심박수 측정 장치(Alpha, MIO, USA)를 포화도 측정기(MP110, MECKIS, Republic of Korea)와 비교하였으며 이를 위해 10명의 성인을 대상으로 안정시와 운동 직후의 심박수를 두 기기를 동시에 장착하여 측정된 데이터를 Wilcoxon Singed Rank test를 시행하였다(p < 0.05). 두 기기에서 측정된 데이터 간의 유의한 차이가 없었다(p < 0.05).

• 한국산업보건학회지
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• 제8권1호
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• pp.36-49
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• 1998

The purpose of this study is to investigate the relationship between the work postures and upper extremity cumulative trauma disorders(CTDs) in female medical insurance bill reviewers(n=448). This study included diagnosis for CTDs, anthropometry and job analysis (workstations and posture). The characteristics of subject were 33.6 years of average age and 8.7 years of average work duration. The results were as fallows. Ergonomic conditions of workstation were unsuitable compared with anthropometry result. The height of work surface(79.5 cm) and chair(43.0 cm)were high. work space was small, and legs space under the table was limited. Work postures were awkward compared with recommended neutral postures. Neck flexion($21.0-36.0^{\circ}$), elbow elevation, shoulder abduction ($46.0-47.0^{\circ}$). wrist radial and ulnar deviation, forearm supination and pronation, and wrist repeated motion(12.7-21.5 freq./min) were analyzed as hazardous risk factors by job analysis. The prevalence of CTDs was 32.8 % by medical diagnosis. The prevalence rate of CTDs in hazardous work posture group was significantly greater than safe work posture group both neck-shoulder (relative prevalence = 5.2, p<0.001) and wrist-hand (relative prevalence = 2.5, p<0.05).