Go to the main menu
Skip to content
Go to bottom
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 17, Issue 4 - Dec 1996
Volume 17, Issue 3 - Sep 1996
Volume 17, Issue 2 - Jun 1996
Volume 17, Issue 1 - Mar 1996
Selecting the target year
A Study on Protein Adsorption-resistant Soft Contact Lens
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 291~296
Poly(ethylene glycol)(PEG) macromers terminated with diacrylate Iyoups and interpenetrating poly- mer networks(IPN) composed of poly(hydroxyethyl methacrylate)(PHEMA) or poly(hydroxyethyl methacrylate-co-hydronypropyl methacrylate-co- N-vinyl pyrrolidone ) [ P( HEM A-co- HPM A-co- NVP) ] and PEG macromer were synthesized with the aim of obtaining protein adsorption resistant soft contact lens. Polymerization of PEC macromer resulted in the formation of cross-linked gels due to the multifunctionality of macromer. Crosslinked P(HEMA) or P(HEMA-co-HPMA-co-WVP) chains were interpenetrated into the cross-linked three-dimensional networks of PEG. It was found that albumin adsorption onto the contact lens prepared by P(HEMA-co-HPMA-co-NVP) /PEG IPW decreases with an increase of molecular weight of PEG. Also, it was found that albumin adsorption onto the both contact lens decreases with an increase of concentration of PEC macromer in the IPN preparation. There are also more adequate in the bioinertnen for the contact lens by P(HEMA)/PEG IPN or P (HEMA-co-HPMA-co-NVP)/PEG IPN than that by P(HEMA) or P(HEMA-co-HPMA-co-NVP)
Analysis of Telopeptide Removal in Type I Collagen Purified From Human Umbilical Cords
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 297~304
Although collagen is still considered to be a poor immunogen, animals can produce antibodies to a number of different sites in the collagen molecule. In type I collagen, three classes of antigenic determinants have been described those are recogrlized as different degrees in different species. These are essentially composed of helical, conformation-dependent antigenic determinants and terminal, nonhelical antigenic determinants, and finally central antigenic determinants exposed only after denaturation of the collagen molecule. To utilize collagen as implantable biomateriall human e61bryonic collagen, ten immunological to body, was purified from human umbilical cords and found to contain [
2(I). Each step of purification were observed by polarized light microscope and analyzed through SDS-PAGE. The conclusious are follows; 1 . The purified collagen revealed gradual fiber indenties on each step of purification by polarized microscope. 2. The structual changes of extracted collagen as removed telopeptide were confirmed by SDS-PAGE.
Fractal Coding of Three Dimensional Medical Images with Perceptually Enhanced Matching
Ahn, C.B ; Song, Y.C ; Shin, H.S ;
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 305~312
A new three dimensional fractal coding is proposed with a perceptually enhanced matching. Since most of medical images (e.g. computed tomoyaphy or magnetic resonance images) have three dimensional characters, searching regions are extended to adjacent slices. For a perceptually enhanced matching, a high frequency boost filter is used for pre-filtering images to be encoded, and a least mean square error matching is applied to the edge enhanced Images rather than the original images. From simulation with magnetic resonance images(
, 8bits/pixel), reconstructed images by the proposed compression algorithm show much improved subjective image quality with higher peak signnal-to-noise ratio compared to those by existing fractal coding algorithms at compression ratios of about 10.
Postural Balance Rehabilitation using Virtual Reality Technology
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 313~318
We proposed a new system for the postural balance rehabilitation training. For the purpose, we used the virtual hiking system using virtual reality technology. We evaluated the system by measuring the parameters such as path deviation, path deviation velocity, cycling time, and head movement. From our results, we verified the usefulness of virtual reality technology in rehabilitation. Our results showed that this system was effective postural balance rehabilitation training device and might be useful as the clinical equipment.
An Algorithm for the Optimum Separation of Superimposed EMG Signal Using Wavelet Filter
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 319~326
Clinical myography(EMG) is a technique for diagnosing neuromuscular disorders by analyzing the electrical signal that can be records by needle electrode during a muscular contraction. The EMG signal arises from electrical discharges that accompany the generation of force by groups of muscular fiber, and the analysis of EMG signal provides symptoms that can distinguish disorder of mLecle from disor- ders of nerve. One of the methods for analysis of EMG signal is to separate the individual discharge-the motor unit action potentials(MVAPS) - from EMG signal. But we can only observe the EMG signal that is a superimposed version of time delayed MUAPS. To obtain the information about MUAP(, i.e., position, firing number, magnitude etc), first of all, a method that can separate each MUAP from the EMG signal must be developed Although the methods for MUAP separation have been proposed by many researcherl they have required heavy computational burden. In this paper, we proposed a new method that has less computational burden and performs more reliable separation of superimposed EMG signal using wavelet filter which has multiresolution analysis as major property. As a result, we develope the separation algorithm of superimposed EMG signal which has less computational burden than any other researchers and exacutes exact separation process. The performance of this method has been discussed in the automatic resolving procedure which is neccessary to identify every firing of every motor unit from the EMG pattern.
Effect of Immersion in Water and Thermal Cycling on the Mechanical Properties of Light-cured Composite Resins
Bae, Tae-Sung ; Kim, Tae-Jo ; Kim, Hyo-Sung ;
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 327~336
This study was performed to investigate the effec% of immersion in water and thermal cycling on the mechanical peoperties of light cured restorative composite resins. Five commerically available light-cured composite resins(Photo Clearfil A : CA, Lite-Fil A . LF, Clearril Photo Posterior CP, Prisms AP.H.. PA, 2100 : ZH) were unto The specimens of 12 m in diameter and 0.7 m in thickness were made, and an immersion in
water for 7 days and a thermal cycling of 1000 cycles at 15 second dwell time each in
baths were performed. Biaxial flexure test was conducted using the ball-on-three-ball method at the crosshead speed of 0.5mm/min. In order to investigate the deterioration of composite resins during the thermal cycling test, Weibull analysis for the biaxial flexure strengths was done. Fracture surfaces and the surfaces before and after the thermal cycling test were examined by SEM. The highest Weibull modulus value of 10.09 after thermal cycling tests which means the lowest strength variation, was observed in the CP group, and the lowest value of 4.47 was obsered in the LF Group. Biaxial flexure strengths and Knoop hardness numbers significantly decreased due to the thermal cycling (
< 0.01), however, they recovered when specimens were drie4 The highest biaxial flexure strength of 125.65MPa was observed in the ZH group after the thermal cycling test, and the lowest value of 64.86MPa was observed in the CA group. Biaxial flexure strengths of ZH and CP groups were higher than those of PA, CF, and CA groups after thermal cycling test(
< 0.05). Knoop hardness numbers of CP group after the thermal cycling test was the highest(95.47
) among the samples, while that of CA group was the lowest(30.73
). Knoop hardness numbers showed the significant differences between the CP group and others after the thermal cycling test((
< 0.05). Fracture surfaces showed that the composite resin failure developed along the matrix resin and the filler/resin interface region, and the cracks propagated in the conical shape from the maximum tensile stress zone.
The Effects of Flow Wave form on the Flow Characteristics in Tapered Vascular Grafts
Lee, Hyeon-Cheol ; Seok, Gwang-Won ; Jeon, Cheol-Wan ; Lee, Jin ; Lee, Yeong-Seok ; Kim, Seong-Hwan ;
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 337~346
The patency of small size vascular grafts is poor, and the blood flow characteristics in the artery graft anastomosis are suspected as one of the important factors influencing intimal hyperplasia. Disturbed flow patterns caused by sixte and compliance mismatch generate unfavorable flow environment which promotes intimal thickening. Tapered vascular yuts are suggested in order to reduce sudden expansion near the anastomosis. The photochromic flow visualization method is used to measure the flout fields in the end-to-end anastomosis model under the carotid and femoral artery flow wave form. The results show that flow disturbance near the anastomosis is diminished in the tapered grafts comparing to the tubular graft. As the divergent ang1e decreases, we can reduce the low and oscillatory wall shear stress zone which is prone to intimal hyperplasia. The flow wave form effects the wall shear rate dis- tribution significantly. The steep deceleration and back flow in the femoral flow wAve form cause low mean wall shear rate and high oscillatory shear index.
A Study on the Design of a Digital Hearing Aids Signal Processing System in the Wavelet Transform Domain
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 347~354
This paper presents digital hearing aids signal processing system in WT(wavelet transform) domain. For implementation of hearing aids in WT domain, the gain in frequency domain is approximated in WT domain. We also present the gain selection algorithm to deal with the change of input signal power. Most transform methods produce blocking effect, and this effect degrades the convergence rate of feedback canceller. As a solution, we proposed wavelet transform bascd feedback canceller. To evaluate the performance, we compared it with LOT (lapped orthogonal transform) method in the frequency domain. This system has not shown the blocking effect, and improves convergence rate as compared with the LOT based feedback canceller.
Retention of Endothelial Cells adhered on Polyurethane Surface under Flow Condition
Chang, Jun-Keun ; Chang, Hyun-A ; Kim, Jin-Hee ; Kim, Jong-Won ; Han, Dong-Chul ; Min, Byoung-Goo ;
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 355~364
Construction of the stable monolayer of endothelial cells onto physicochemically modified polymeric surFace is one of the appropriate method to develop the small caliber vascular graft with the long-term patency. In this study, we constructed the monolayer of endothelial cells on the fibronectin rind the extracellular matrix-coated polyurethane surface derived from human fibroblast cells. To elucidate the adhesion strength of endothelial cells on the extracellular matrix-coated polyurethane, a laminar flow chamber apparatus was developed to exposure the shear stress on the apical membrane of ondothelial cells. Endothelial cells show the strongest adhesion after two days of seeding onto the fibronectin-coated polyurethane surface, whereas endothelial cells on the extracellular matrix derived from the human flbroblast cells show the minimal doubling time of cellular growth.
The Endocardial Boundary Detection based on Statistical Charact'eristics of Echocardiographic Image
Won, Chul-Ho ; Kim, Myoung-Nam ; Cho, Jin-Ho ;
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 365~372
The researches to acquire diagnostic parameters from ultrasonic images are advanced with the progress of the digital image processing technique. Especially, the detection of endocardial boundary is very important in ultrasonic images, because endocardial boundary is used as a clinical parameter to estimate both the cardiac area and the variation of cardiac volume. Various methods to detect cardiac boundary are proposed, but these are insufficient to detect boundary. In this paper, an algorithm that detects the endocardial boundary, expanding the cavity region from the center using statistical information, is proposed The value of mean and sty:nd, wd deviation in cavity region is lower than those in muscle re- gion. Therefore, if we define the multiplication of mean and standard deviation as homogeneous coefficient, it can lead to conclusion that the pixels with small variation of these coefficleno are cavity region, and extraction of endocardial boundary from cavity region is possible. The proposed method detected endocardial boundary more effectively than edge based or threshold based method and is robuster to noise than radial searching method that has high dependency for center position.
Optimal Conditions of Braille Recognition System Using Electrical Stimulus
Lee, Seungjik ; Shin, Jaeho ; Shin, Jaeho ;
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 373~378
In this paper, we calculated chronaxy value in order to determine the optimal conditions and stimulus pulse of information transmission. We also developed an electrical equivalent circuit of the hand including the contact part, which consists of two resistors (a contact resistor and finger resistor) and a capacitor. The minimum recoulition voltage was measured by using electrical stimulus. We found that the ranges of the above two resistances and the capacitance are 30-130k
and 10-30nF respectively. We found that the minimum recoulition voltage was the lowest at 100-300Hz and 10% of the duty ratio.
An EMG Signals Discrimination Using Hybrid HMM and MLP Classifier for Prosthetic Arm Control Purpose
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 379~386
This paper describes an approach for classifying myoelectric patterns using a multilayer perceptrons (MLP's) and hidden Markov models (HMM's) hybrid classifier. The dynamic aspects of EMG are important for tasks such as continuous prosthetic control or vari- ous time length EMG signal recognition, which have not been successfully mastered by the most neural approaches. It is known that the hidden Markov model (HMM) is suitable for modeling temporal patterns. In contrasts the multilayer feedforward networks are suitable for static patterns. Ank a lot of investigators have shown that the HMM's to be an excellent tool for handling the dynamical problems. Considering these facts, we suggest the combination of MLP and HMM algorithms that might lead to further improved EMG recognition systems.
Adaptively Trained Artificial Neural Network Identification of Left Ventricular Assist Device
Kim, Sang-Hyun ; Kim, Hun-Mo ; Ryu, Jung-Woo ;
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 387~394
This paper presents a Neural Network Identification(NNI) method for modeling of highly complicated nonlinear and time varing human system with a pneumatically driven mock circulatory system of Left Ventricular Assist Device(LVAD). This system consists of electronic circuits and pneumatic driving circuits. The initiation of systole and the pumping duration can be determined by the computer program. The line pressure from a pressure transducer inserted in the pneumatic line was recorded System modeling is completed using the adaptively trained backpropagation learning algorithms with input variables, heart rate(HR), systole-diastole rate(SDR), which can vary state of system. Output parameters are preload, afterload which indicate the systemic dynamic characteristics. Consequently, the neural network shows good approximation of nonlinearity, and characteristics of left Ventricular Assist Device. Our results show that the neural network leads to a significant improvement in the modeling of highly nonlinear Left Ventricular Assist Device.
A Study on EMG Signals Recognition using Time Delayed Counterpropagation Neural Network
Kwon, Jangwoo ; Jung, Inkil ; Hong, Seunghong ;
Journal of Biomedical Engineering Research, volume 17, issue 3, 1996, Pages 395~401
In this paper a new neural network model, time delayed counterpropagation neural networks (TDCPN) which have high recognition rate and short total learning time, is proposed for electromyogram(EMG) recognition. Signals the proposed model increases the recognition rates after learned the regional temporal correlation of patterns using time delay properties in input layer, and decreases the learning time by using winner-takes-all learning rule. The ouotar learning rule is put at the output layer so that the input pattern is able to map a desired output. We test the performance of this model with EMG signals collected from a normal subject. Experimental results show that the recognition rates of the suggested model is better and the learning time is shorter than those of TDNN and CPN.