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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Biomedical Engineering Research
Journal Basic Information
Journal DOI :
The Korea Society of Medical and Biological Engineering
Editor in Chief :
Volume & Issues
Volume 28, Issue 6 - Dec 2007
Volume 28, Issue 5 - Oct 2007
Volume 28, Issue 4 - Aug 2007
Volume 28, Issue 3 - Jun 2007
Volume 28, Issue 2 - Apr 2007
Volume 28, Issue 1 - Feb 2007
Selecting the target year
Posture Change Affects Indices of Pupil Size - Korean Males in Their Twenties
Lee, Jeung-Chan ; Kim, Ji-Eun ; Park, Kyung-Mo ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 1~7
To determine the effect of posture change on autonomic activity and to investigate valid parameters to reflex the autonomic activity from time-series pupil size data, a posture-related experiment was performed with 15 subjects, which involved measuring their electrocardiograms and pupil sizes. The experimental procedure consisted of three-sequence postures-supine, sitting and upright-for 5 minutes each, with rest sessions between postures. The subjects were notified of the entire experimental procedure. The parameters of the subjects' heart rate variability showed significant differences between the postures (heart rate: 63-70-80 beat, normalized low frequency power: 28-50-75, normalized high frequency power: 72-49-25 and ratio: 0.5-1.2-4.4 in supine-sitting-upright position respectively) as did the parameters of their mean pupil sizes (41300-53900-53700 pixels respectively) and the major frequencies (the third trend: 0.23-0.2-0.18 Hz respectively) of their pupil size variability according to changes in their autonomic activities induced by posture change. The experiment thus proved that posture change affects autonomic activity and that such activity can be estimated by the parameters of pupil size as similar as heart rate variability.
Numerical Evaluations of the Effect of Feature Maps on Content-Adaptive Finite Element Mesh Generation
Lee, W.H. ; Kim, T.S. ; Cho, M.H. ; Lee, S.Y. ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 8~16
Finite element analysis (FEA) is an effective means for the analysis of bioelectromagnetism. It has been successfully applied to various problems over conventional methods such as boundary element analysis and finite difference analysis. However, its utilization has been limited due to the overwhelming computational load despite of its analytical power. We have previously developed a novel mesh generation scheme that produces FE meshes that are content-adaptive to given MR images. MRI content-adaptive FE meshes (cMeshes) represent the electrically conducting domain more effectively with far less number of nodes and elements, thus lessen the computational load. In general, the cMesh generation is affected by the quality of feature maps derived from MRI. In this study, we have tested various feature maps created based on the improved differential geometry measures for more effective cMesh head models. As performance indices, correlation coefficient (CC), root mean squared error (RMSE), relative error (RE), and the quality of cMesh triangle elements are used. The results show that there is a significant variation according to the characteristics of specific feature maps on cMesh generation, and offer additional choices of feature maps to yield more effective and efficient generation of cMeshes. We believe that cMeshes with specific and improved feature map generation schemes should be useful in the FEA of bioelectromagnetic problems.
Spatiotemporal Analysis of Hippocampal Long Term Potentiation Using Independent Component Analysis
Kim, T.S. ; Lee, J.J. ; Hwang, S.J. ; Lee, Y.K. ; Park, J.H. ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 17~23
Long-term potentiation (LTP) of synaptic transmission is the most widely studied model for learning and memory. However its mechanisms are not clearly elucidated and are a subject for intense investigation. Previous attempts to decipher cellular mechanisms and network properties involved a current-source density analysis (CSDA) of the LTP from small animal hippocampus measured with a limited number of microelectrodes (typically <3), only revealing limited nature of spatiotemporal dynamics. Recent advancement in multi-electrode array (MEA) technology allows continuous and simultaneous recordings of LTP with more than 60 electrodes. However CSDA via the standard Laplacian transform is still limited due to its relatively high sensitivity toward noise, inability of resolving overlapped current sources and sinks, and its requirement for tissue conductivity values. In this study, we propose a new methodology for improved CSDA. Independent component analysis and its joint use (i.e., Joint-ICA) are applied to extract spatiotemporal components of LTP. The results show that ICA and Joint-ICA are capable of extracting independent spatiotemporal components of LTP generators. The ICs of LTP indicate the reversing roles of current sources and sinks which are associated with LTP.
Detection of Neuronal Activity by Motion Encoding Gradients: A Snail Ganglia Study
Park, Tae-S. ; Park, Ji-Ho ; Cho, Min-H. ; Lee, Soo-Y. ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 24~28
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
when the ganglia were activated by the electrical stimulation.
EMG-Based Muscle Torque Estimation for FES Control System Design
Hyun, Bo-Ra ; Song, Tong-Jin ; Hwang, Sun-Hee ; Khang, Gon ; Eom, Gwang-Moon ; Lee, Moon-Suk ; Lee, Bum-Suk ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 29~35
This study was designed to investigate the feasibility to utilize the electromyogram (EMG) for estimating the muscle torque. The muscle torque estimation plays an important role in functional electrical stimulation because electrical stimulation causes muscles to fatigue much faster than voluntary contraction, and the stimulation intensity should then be modified to keep the muscle torque within the desired range. We employed the neural network method which was trained using the major EMG parameters and the corresponding knee extensor torque measured and extracted during isometric contractions. The experimental results suggested that (1) our neural network algorithm and protocol was feasible to be adopted in a real-time feedback control of the stimulation intensity, (2) the training data needed to cover the entire range of the measured value, (3) different amplitudes and frequencies made little difference to the estimation quality, and (4) a single input to the neural network led to a better estimation rather than a combination of two or three. Since this study was done under a limited contraction condition, the results need more experiments under many different contraction conditions, such as during walking, for justification.
BIOFIT - Smart, Portable, Wearable and Wireless Digital Exercise Trainer Device with Biofeedback Capability
Diwakar Praveen Kumar ; Oh Young-Keun ; Chung Gyo-Bum ; Park Seung-Hun ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 36~45
Today Human Personal Trainers are becoming very famous in this health conscious world. They teach user to achieve fitness goals in managed way. Due to their high fee and tight schedule they are unavailable to mass number of people. Another solution to this problem is to develop digital personal trainer portable instrument that may replace human personal trainers. We developed a portable digital exercise trainer device - BIOFIT that manages, monitors and records the user's physical status and workout during exercise session. It guides the user to exercise efficiently for specific fitness goal. It keeps the full exercise program i.e. exercises start date and time, duration, mode, control parameter, intensity in its memory which helps the user in managing his exercise. Exercise program can be downloaded from the internet. During exercise it continuously monitors the user's physiological parameters: heart rate, number of steps walked, and energy consumed. If these parameters do not range within prescribed target zone, the BIOFIT will alarm the user as a feedback to control exercise. The BIOFIT displays these parameters on graphic LCD. During exercise it continuously records the heart rate and number of steps walked every 10 seconds along with exercise date and time. This stored information can be used as treatment for the user by an exercise expert. Real-time ECG monitoring can be viewed wirelessly (RF Communication) on a remote PC.
The Differential Effects of Acupuncture on Postures of Healthy Subjects
Kim, Ji-Eun ; Park, Kyung-Mo ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 46~54
Objective: The first aim of this study is to determine the effects of acupuncture on the autonomic nervous system (ANS) via Heart Rate (HR) and Pupil Size (PS), and to compare the effects of acupuncture on the subjects' ANS when they are in a sitting position with the effects when they are in a supine position. Methods: Ten healthy male subjects were randomized to receive either verum acupuncture stimulation in a sitting position (SitV), verum acupuncture stimulation in a supine position (SupV), sham acupuncture stimulation in a sitting position (SitS), and sham acupuncture stimulation in a supine position (SupS). Acupuncture stimulation was applied to Neguan point (PC6) on the forearm. The subject's electrocardiogram (ECG) and pupil size were recorded continuously from 5 min before stimulation to 12 min after stimulation. Results: Verum and sham acupuncture stimulation were found to have reduced heart rate (p<0.01) and to have increased pupil size (p<0.01) in all the subjects. But when the reduction in HR and the increment in PS after verum acupuncture stimulation (both sitting and supine position) were compared with those after sham acupuncture stimulation, it was found that the reduction in HR (74.48 and 73.47 bpm, p<0.063) and the increment of PS (7.32 and, 6.10 mm, p<0.001) after verum acupuncture stimulation were greater than those after sham acupuncture stimulation, and that the corresponding values were statistically significant. In addition, at the baseline, it was found that the subjects had a larger PS and a faster HR in a sitting position than when they did so in a supine position. And then the reduction and increment ratio in the subject's HR and PS when they underwent acupuncture stimulation in a sitting position was significantly different from the reduction and increment in their HR and PS when they underwent the procedure in a supine position-i.e., the reduction ratio in HR was greater when they underwent the procedure in a sitting position, and such reduction ratio was statistically significant (p<0.05). As for the increment in PS, it was greater when the subjects underwent the procedure in a supine position, and such increment was significant (p<0.05). Conclusion: Manual acupuncture stimulation on Neguan point (PC6) has more significant influence on the autonomic nervous system rather than sham acupuncture (tactile stimulation). And the position-induced different states of ANS have different influence on the acupuncture effect.
Pupil Size Variability as an Index of Autonomic Activity - from the Experiments of Posture, Sleepiness and Cognitive Task
Lee, Jeung-Chan ; Kim, Ji-Eun ; Park, Kyung-Mo ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 55~65
This paper sought to investigate pupil size variability, pupil size parameters in terms of time domain and frequency domain, the autonomic activity change induced by posture change, degree of sleepiness and cognitive task (math task). With a specially designed pupil image acquisition system in the dark room, these three kinds of experiments were performed to induce a dominant state of sympathetic or parasympathetic activation. Electrocardiogram and pupil size were measured in all the experiments. Based on three experiments, we calculated heart rate variability. In the pupil size analysis, we calculated the mean and standard deviation of pupil size (in time domain), and proposed several frequency bands that exhibit different autonomic activation between different sessions. The results indicate that in terms of heart rate variability, posture change exhibited significant differences but not between sleepiness level, or between cognitive task. Pupil sizes differed only during the postures. And we found some frequency bands that correlated with autonomic activation in each experiment. While heart rate variability reflects posture change that need cardiac control, pupil size variability reflects not only posture induced autonomic activation but sleepiness and cognitive load, which is processed in the brain, in time and frequency domain parameter.
Multi-Frequency Electrical Impedance Tomography System
Oh, Tong-In ; Cho, Seong-Phil ; Kim, Sang-Min ; Koo, Hwan ; Woo, Eung-Je ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 66~74
We have developed a multi-channel, multi-frequency EIT system with operating frequency of 10Hz to 500KHz. The number of digital voltmeters using phase-sensitive demodulation can be varied from 8 to 64 and we found that 16 and 32-channels are most practical. This paper describes the design, implementation, and construction of 16 and 32-channel systems. The performance of the system was thoroughly tested and we found that CMRR of the developed voltmeter is about 85dB with
unbalancing series resistor. The SNR is greater than 99.6dB and the output impedance of the constant current source is
at least for all frequencies. Imaging experiments using a banana with frequency-dependent conductivity and permittivity show that frequency-difference imaging is possible using the developed system. Future works of animal and human experiments are discussed.
Development of Vibrator for Magnetic Resonance Elastography
Lee, Tae-Hwi ; Suh, Yong-Seon ; Kim, Young-Tea ; Lee, Byung-Il ; Woo, Eung-Je ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 75~83
Elasticity is an important physical property of biological tissues. Differences in elasticity can help facilitate the diagnosis of tumors and their extent. Magnetic Resonance Elastography (MRE) tries to visualize images of tissue elasticity by externally applying shear stress on the surface of an imaging object. Applied shear stress induces internal displacements that can be measured from MR phase images. In order to conduct MRE imaging experiments, we need to first develop a vibrator. We found that there does not exist enough technical information to design the MRE vibrator. In this paper, we describe the theory, design and construction of an MRE vibrator. We report the performance of the developed vibrator using two different test methods. We found that the vibrator successfully induces enough internal displacements that can be imaged using an MRI scanner. We suggest future studies of numerous MRE imaging experiments using the vibrator.
320-Channel Multi-Frequency Trans-Admittance Scanner(TAS) for Anomaly Detection
Oh, Tong-In ; Lee, Min-Hyoung ; Kim, Hee-Jin ; Woo, Eung-Je ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 84~94
In order to collect information on local distribution of conductivity and permittivity underneath a scan probe, we developed a multi-frequency trans-admittance scanner (TAS). Applying a sinusoidal voltage with variable frequency on a chosen distal part of a human body, we measure exit currents from 320 grounded electrodes placed on a chosen surface of the subject. The electrodes are packaged inside a small and light scan probe. The system includes one voltage source and 17 digital ammeters. Front-end of each ammeter is a current-to-voltage converter with virtual grounding of a chosen electrode. The rest of the ammeter is a voltmeter performing digital phase-sensitive demodulation. Using resistor loads, we calibrate the system including the scan probe to compensate frequency-dependent variability of current measurements and also inter-channel variability among multiple. We found that SNR of each ammeter is about 85dB and the minimal measurable current is 5nA. Using saline phantoms with objects made from TX-151, we verified the performance of the lesion estimation algorithm. The error rate of the depth estimation was about 19.7%. For the size estimate, the error rate was about 15.3%. The results suggest improvement in lesion estimation algorithm based on multi-frequency trans-admittance data.
Development of High Resolution Micro-CT System for In Vivo Small Animal Imaging
Park, Jeong-Jin ; Lee, Soo-Yeol ; Cho, Min-Hyoung ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 95~101
Recently, small-animal imaging technology has been rapidly developed for longitudinal screening of laboratory animals such as mice and rats. One of newly developed imaging modalities for small animals is an x-ray micro-CT (computed tomography). We have developed two types of x-ray micro-CT systems for small animal imaging. Both systems use flat-panel x-ray detectors and micro-focus x-ray sources to obtain high spatial resolution of
. In spite of the relatively large field-of-view (FOV) of flat-panel detectors, the spatial resolution in the whole-body imaging of rats should be sacrificed down to the order of
due to the limited number of x-ray detector pixels. Though the spatial resolution of cone-beam CTs can be improved by moving an object toward an x-ray source, the FOV should be reduced and the object size is also limited. To overcome the limitation of the object size and resolution, we introduce zoom-in micro-tomography for high-resolution imaging of a local region-of-interest (ROI) inside a large object. For zoom-in imaging, we use two kinds of projection data in combination, one from a full FOV scan of the whole object and the other from a limited FOV scan of the ROI. Both of our micro-CT systems have zoom-in micro-tomography capability. One of both is a micro-CT system with a fixed gantry mounted with an x-ray source and a detector. An imaged object is laid on a rotating table between a source and a detector. The other micro-CT system has a rotating gantry with a fixed object table, which makes whole scans without rotating an object. In this paper, we report the results of in vivo small animal study using the developed micro-CTs.
Numerical Study on the Sub-Voxel Tracking Using Micro-Beads in a 3.0 T MRI
Han, Byung-Hee ; Lee, Soo-Yeol ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 102~107
In molecular imaging studies via magnetic resonance imaging, in vivo cell tracking is an important issue for the observation of cell therapy or disease behavior. High resolution imaging and longitudinal study are necessary to track the cell movement. Since the field inhomogeneity extends over several voxels, we have performed the numerical analysis using the sub-voxel method dividing a voxel of MR image into several elements and the information about the field inhomogeneity distribution around the micro-beads. We imbedded ferrite-composite micro-beads with the size of
in the subject substituted for cells to induce local field distortion. In the phantom imaging with the isotropic voxel size of
, we could confirm the feasibility of sub-voxel tracking in a 3.0 T MRI.
Influence of Malalignment on Tibial Post in Total Knee Replacement Using Posterior Stabilized Implant
Kim, Sang-Hoon ; Ahn, Ok-Kyun ; Bae, Dae-Kyung ; Kim, Yoon-Hyuk ; Kim, Kyung-Soo ; Lee, Soon-Gul ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 108~116
Recently, it has been reported that the posterior stabilized implant, which is clinically used for the total knee replacement (TKR), may have failure risk such as wear or fracture by the contact pressure and stress on the tibial post. The purpose of this study is to investigate the influence of the mal alignment of the posterior stabilized implant on the tibial post by estimating the distributions of contact pressure and von-Mises stress on a tibial post and to analyze the failure risk of the tibial post. Finite element models of a knee joint and an implant were developed from 1mm slices of CT images and 3D CAD software, respectively. The contact pressure and the von-Mises stress applying on the implant were analyzed by the finite element analysis in the neutral alignment as well as the 8 malalignment cases (3 and 5 degrees of valgus and varus angulations, and 2 and 4 degrees of anterior and posterior tilts). Loading condition at the 40% of one whole gait cycle such as 2000N of compressive load, 25N of anterior-posterior load, and 6.5Nm of torque was applied to the TKR models. Both the maximum contact pressure and the maximum von-Mises stress were concentrated on the anterior-medial region of the tibial post regardless of the malalignment, and their magnitudes increased as the degree of the malalignment increased. From present result, it is shown that the malalignment of the implant can influence on the failure risk of the tibial post.
A New Training System for Improving Postural Balance Using a Tilting Bed
Yu, Chang-Ho ; Kwon, Tae-Kyu ; Ryu, Mun-Ho ; Kim, Nam-Gyun ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 117~126
In this paper, we propose an early rehabilitation training system for the improvement of postural balance with multi-modality on a tilting bed. The integration of the visual, somatosensory and vestibular functions is significant to for maintaining the postural control of the human body. However, conventional rehabilitation systems do not provide multi-modality to trainees. We analyzed the characterization of postural control at different tilt angles of an early rehabilitation training system, which consists of a tilting bed, a visual feedback, a computer interface, a computer, and a force plate. The software that we developed for the system consists of the training programs and the analysis programs. To evaluate the characterization of postural control, we conducted the first evaluation before the beginning of the training. In the following four weeks, 12 healthy young and 5 healthy elderly subjects were trained to improve postural control using the training programs with the tilting bed. After four weeks of training, we conducted the second evaluation. The analysis programs assess (center of pressure) COP moving time, COP maintaining time, and mean absolute deviation of the trace before and after training at different tilt angles on the bed. After 4 weeks, the COP moving time was reduced, the COP maintaining time was lengthened, and the mean absolute deviation of the trace was lowered through the repeated use of vertical, horizontal, dynamic circle movement training programs. These results show that this system improves postural balance and could be applied to clinical use as an effective training system.
New Matching Scheme for Panorama Image: A Simulation Study
Kim, Jeong-Seok ; Chung, Sung-Taek ; Hong, In-Ki ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 127~131
This paper presents a new matching scheme for creating a single panoramic image from a sequence of partially overlapping images of the same object or scene. This matching scheme is based directly on the searching algorithm, using a multiscale approach to the Hooke-Jeeves algorithm. Matching scheme evaluation was performed using simulated pattern images. The proposed matching scheme reveals good results and could be effectively applied to real ultrasound applications.
Design of ECG/PPG Gating System in MRI Environment
Jang, Bong-Ryeol ; Park, Ho-Dong ; Lee, Kyoung-Joung ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 132~138
MR(magnetic resonance) image of moving organ such as heart shows serious distortion of MR image due to motion itself. To eliminate motion artifacts, MRI(magnetic resonance imaging) scan sequences requires a trigger pulse like ECG(electro-cardiography) R-wave. ECG-gating using cardiac cycle synchronizes the MRI sequence acquisition to the R-wave in order to eliminate image motion artifacts. In this paper, we designed ECG/PPG(photo-plethysmography) gating system which is for eliminating motion artifacts due to moving organ. This system uses nonmagnetic carbon electrodes, lead wire and shield case for minimizing RF(radio-frequency) pulse and gradient effect. Also, we developed a ECG circuit for preventing saturation by magnetic field and a finger plethysmography sensor using optic fiber. And then, gating pulse is generated by adaptive filtering based on NLMS(normalized least mean square) algorithm. To evaluate the developed system, we measured and compared MR imaging of heart and neck with and without ECG/PPG gating system. As a result, we could get a clean image to be used in clinically. In conclusion, the designed ECG/PPG gating system could be useful method when we get MR imaging of moving organ like a heart.
Activations of Cerebral and Cerebellar Cortex Induced by Repetitive Bilateral Motor Excercise
Tae, Ki-Sik ; Song, Sung-Jae ; Kim, Young-Ho ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 139~147
The aim of this study was to evaluate effects of short-tenn repetitive-bilateral excercise on the activation of motor network using functional magnetic resonance imaging (fMRI). The training program was performed at 1 hr/day, 5 days/week during 6 weeks. Fugl-Meyer Assessments (FMA) were performed every two weeks during the training. We compared cerebral and cerebellar cortical activations in two different tasks before and after the training program: (1) the only unaffected hand movement (Task 1); and (2) passive movements of affected hand by the active movement of unaffected hand (Task 2). fMRI was performed at 3T with wrist flexion-extension movement at 1 Hz during the motor tasks. All patients showed significant improvements of FMA scores in their paretic limbs after training. fMRI studies in Task 1 showed that cortical activations decreased in ipsilateral sensorimotor cortex but increased in contralateral sensorimotor cortex and ipsilateral cerebellum. Task 2 showed cortical reorganizations in bilateral sensorimotor cortex, premotor area, supplemetary motor area and cerebellum. Therefore, this study demonstrated that plastic changes of motor network occurred as a neural basis of the improvement subsequent to repetitive-bilateral excercise using the symmetrical upper-limb ann motion trainer.
Nano Phosphor and Optical Characteristics for High Resolution Radiation Imaging
Kim, So-Yeong ; Kang, Sang-Sik ; Park, Ji-Koon ; Cha, Byung-Youl ; Choe, Chi-Won ; Lee, Hyung-Won ; Nam, Sang-Hee ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 148~152
In this paper, we have synthesized
nano phosphor particle using a low temperature solution-combustion method. We have investigated the structure and the luminescent characteristic as the sintering temperature and europium concentration. From XRD(X-ray diffraction) and SEM(scanning electron microscope) results, we have verified that the phosphor particle was fabricated a spherical shape with
particle size. From the photoluminescence results, the strong peak exhibits at 611 um and the luminescent intensity depends on europium concentration.
fine phosphor particle has shown excellent luminescent efficiency at 5 wt% of europium concentration. The phosphors calcinated at
have possessed the x-ray peaks corresponding to the cubic phase of
. As calcinations temperature increased to
, the new monoclinic phase has identified except cubic patterns. From the luminescent decay time measurements, mean lifetimes were
relatively higher than conventional bulk phosphors. These results indicate that
nano phosphor is possible for the operation at the low x-ray dose, therefore, the application as medical imaging detector.
Development of Wireless Neuro-Modulation System for Stroke Recovery Using ZigBee Technology
Kim, G.H. ; Ryu, M.H. ; Shin, Y.I. ; Kim, H.I. ; Kim, N.G. ; Yang, Y.S. ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 153~161
Stroke is the second most significant disease leading to death in Korea. The conventional therapeutic approach is mainly based on physical training, however, it usually provides the limited degree of recovery of the normal brain function. The electric stimulation therapy is a novel and candidate approach with high potential for stroke recovery. The feasibility was validated by preliminary rat experiments in which the motor function was recovered up to 80% of the normal performance level. It is thought to improve the neural plasticity of the nerve tissues around the diseased area in the stroked brain. However, there are not so much research achievements in the electric stimulation for stroke recovery as for the Parkinson's disease or Epilepsy. This study aims at the developments of a wireless variable pulse generator using ZigBee communication for future implantation into human brain. ZigBee is widely used in wireless personal area network (WPAN) and home network applications due to its low power consumption and simplicity. The developed wireless pulse generator controlled by ZigBee can generate various electric stimulations without any distortion. The electric stimulation includes monophasic and biphasic pulse with the variation of shape parameters, which can affect the level of recovery. The developed system can be used for the telerehabilitation of stroke patient by remote control of brain stimulation via ZigBee and internet. Furthermore, the ZigBee connection used in this study provides the potential neural signal transmission method for the Brain-Machine Interface (BMI).
A Study on the Multi-View Based Computer Aided Diagnosis in Digital Mammography
Choi, Hyoung-Sik ; Cho, Yong-Ho ; Cho, Baek-Hwan ; Moon, Woo-Kyoung ; Im, Jung-Gi ; Kim, In-Young ; Kim, Sun-I. ;
Journal of Biomedical Engineering Research, volume 28, issue 1, 2007, Pages 162~168
For the past decade, the full-field digital mammography has been widely used for early diagnosis of breast cancer, and computer aided diagnosis has been developed to assist physicians as a second opinion. In this study, we try to predict the breast cancer using both mediolateral oblique(MLO) view and craniocaudal(CC) view together. A skilled radiologist selected 35 pairs of ROIs from both MLO view and CC view of digital mammogram. We extracted textural features using Spatial Grey Level Dependence matrix from each mammogram and evaluated the generalization performance of the classifier using Support Vector Machine. We compared the multi-view based classifier to single-view based classifier that is built from each mammogram view. The results represent that the multi-view based computer aided diagnosis in digital mammogram could improve the diagnostic performance and have good possibility for clinical use to assist physicians as a second opinion.