• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.266-270
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• 1996

External linkage type spine motion analyzer was developed for measuring relative trunk motion respect to the pelvis. A special program for calculation of the relative angular motion and graphical display were also developed. The developed device assured its accuracy and conveniency after application to 15 normal volunteers and 18 patients after fixation and decompression surgery. Compare to the normal subjects, patients shows different angular motion especially in the angular acceleration.

• Journal of Biomedical Engineering Research
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• v.37 no.1
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• pp.1-6
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• 2016

The biomedical information (heart rate, HRV, $SpO_2$ etc) from the Photoplethysmography (PPG) signal section can be estimated without the motion artifacts if the PPG signal section in the motion artifacts is detected accurately. But the PPG signal is easily exposed to the motion artifacts by the decrease of the medical instrument size and applying as portable or wearable. Besides, it is difficult to completely eliminate the motion artifacts from the PPG signal without distortion and ensure reliability as well. In this paper, the method was suggested to determine the motion artifacts or not on the PPG signal of the section divided into intervals of constant length. By comparing the spectrum of each section, it can be determined whether the motion artifacts are or not after obtaining the spectrum of each section by the Goertzel algorithm. Moreover, an amount of computation while maintaining a high detection rate can be reduced by using the Goertzel algorithm.

• Journal of Biomedical Engineering Research
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• v.28 no.1
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• pp.24-28
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• 2007

Presuming that firing neurons have motions inside the MRI magnet due to the interaction between the neuronal magnetic field and the main magnetic field, we applied motion encoding gradients to dissected snail ganglia to observe faster responding MRI signal than the BOLD signal. To activate the snail ganglia in synchronization with the MRI pulse sequence, we used electrical stimulation with the frequency of 30 Hz and the pulse width of 2s. To observe the fast responding signal, we used the volume selected MRI sequence. The magnetic resonance signal intensity, measured with 8 ms long motion encoding gradient with a 20mT/m gradient strength, decreased about $3.46{\pm}1.48%$ when the ganglia were activated by the electrical stimulation.

• Proceedings of the KOSOMBE Conference
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• v.1989 no.05
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• pp.71-73
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• 1989

The origins of the motion artifact resulting from exercise in impedance cardiography wore explained and the ensemble average technique was applied to reduce the motion artifact enabling the measurement of cardiac output during exercise. Algorithm for ensemble average was developed and applied to the actual impedance signals. It was found that the minimum number of sampling was 20, and sampling frequency was 500Hz. Using the ensemble average technique it was possible to measure cardiac output continuously during the treadmill exercise. Therefore it is hoped that this study may contribute in the area of exercise physiology and sport medicine.

• Journal of Biomedical Engineering Research
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• v.32 no.3
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• pp.191-197
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• 2011

Lifting chair is a typical assistive product to aid for standing up and sitting down for persons with disability. It is particularly useful for the elderly persons whose muscular system is weakened by degenerative joint disease. This paper describes biomechanical assessments of lifting chair with hip-up function. In experiments we measured 3D motion and electromyographic(EMG) signal on the femoral muscle when subject performs the standing motion on the predetermined seat height. Based on assessment of the standing motion, we select the hip-up angle as 15 degrees to cover the relative femoral angle when EMG peak value is appeared. Using an implemented prototype lifting chair with hip-up function we perform standing experiments with five subjects. The experimental results show that the lifting and hip-up functions are effective to assist for standing up motion with less muscle force.

• Journal of Biomedical Engineering Research
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• v.14 no.1
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• pp.1-8
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• 1993

In this study, the extractions of formants and articulatory motion trajectories for Korean complex vowels are performed by using the RLSL adaptive linear prediction filter. This enables us to extract accurate spectrum in transition of speech signal. This study shows that the RLSL algorithm is superior to the Levinson algorithm, specially in transition part of speech.

• Journal of Digital Convergence
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• v.13 no.4
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• pp.357-368
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• 2015

People observe lots of events around the environment and we can easily recognize the nature of an event from the resulting optic flow. The questions are how do people recognize events and what is the information in the optic flow that enables observers to recognize events. Motor theorists claim that human observers exhibit special sensitivity when perceiving events like speech or biological motion, because we both produce and perceive those events. However, direct perception theorists suggested that speech or biological motion is not special from the perception of all other kinds of event. The purpose of this review article is to address this controversy to critique the motor theory and to describe a direct realist approach to event perception. It is important to understand the fundamental information of how human perceive event perception for the convergence on robotics.

• Journal of Biomedical Engineering Research
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• v.28 no.5
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• pp.676-683
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• 2007

A non-invasive respiratory gated radiotherapy system like those based on external anatomic motion gives better comfortableness to patients than invasive system on treatment. However, higher correlation between the external and internal anatomic motion is required to increase the effectiveness of non-invasive respiratory gated radiotherapy. Both of invasive and non-invasive methods need to track the internal anatomy with the higher precision and rapid response. Especially, the non-invasive method has more difficulty to track the target position successively because of using only image processing. So we developed the system to track the motion for a non-invasive respiratory gated system to accurately find the dynamic position of internal structures such as the diaphragm and tumor. The respiratory organ motion tracking apparatus consists of an image capture board, a fluoroscopy system and a processing computer. After the image board grabs the motion of internal anatomy through the fluoroscopy system, the computer acquires the organ motion tracking data by image processing without any additional physical markers. The patients breathe freely without any forced breath control and coaching, when this experiment was performed. The developed pattern-recognition software could extract the target motion signal in real-time from the acquired fluoroscopic images. The range of mean deviations between the real and acquired target positions was measured for some sample structures in an anatomical model phantom. The mean and max deviation between the real and acquired positions were less than 1mm and 2mm respectively with the standardized movement using a moving stage and an anatomical model phantom. Under the real human body, the mean and maximum distance of the peak to trough was measured 23.5mm and 55.1mm respectively for 13 patients' diaphragm motion. The acquired respiration profile showed that human expiration period was longer than the inspiration period. The above results could be applied to respiratory-gated radiotherapy.

• Journal of Biomedical Engineering Research
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• v.24 no.6 s.81
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• pp.543-548
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• 2003

Injuries of wrist in upper extremity is common onset in industrialized world. The development of joint arthroplasty and mechanical joint is area of research for biomechanical engineer and surgeon for a decade. Therefore. the knowledge of characteristic of joint motion is essential to develop the artificial wrist joint. In this study. the joint motions of wrist required for activities of daily living (ADLs). including personal hygiene and care. and general home activity were measured using flexible electrogoniometer. Total of 25 different daily activities were separated into four groups and tested on 15 subjects who did not show any abnormality of their joint functions. The maximum functional range of motion required for ADLs were obtained and standardized for analysis and comparison. Also. a least functional range of motion for ADLs were investigated. Results revealed that any significant differences were not found in least functional range of motion between left and right wrist to perform ADLs. However. a significant difference was found in different ADLs. Therefore. least range of motion obtained in this study can be used as basic data to design artificial joint and set a goal for surgeon to achieve appropriate treatment from patients.

• Journal of Biomedical Engineering Research
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• v.23 no.2
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• pp.87-99
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• 2002

This paper describes a method for overcoming the motion artifacts inherent in synthetic aperture(SA) imaging. based on the investigation results as to the influence of a target motion on synthetic aperture techniques. This method uses a region-based motion compensation approach in which only the axial motion is estimated and compensated for a given region of interest(ROI) under the assumption that the whole ROI moves uniformly The estimated axial motion is calculated with a crosscorrelation(CC) method at the Point where the focused signal has the maximum energy within the ROI. We also presents a method for estimating the axial motion using the autocorrelation(AC) method that is widely used to estimate average Doppler frequency Both computer simulations and in vivo experiments show that the proposed methods can improve greatly the spatial resolution and SNR of ultrasound imaging by implementing the SA techniques for two-way dynamic focusing without motion artifacts. In addition the AC-barred motion compensation method provides almost the same results as the CC-based one, but with a dramatically reduced computational complexity.