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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Biomedical Engineering Research
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The Korea Society of Medical and Biological Engineering
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Volume & Issues
Volume 11, Issue 2 - Dec 1990
Volume 11, Issue 1 - Jun 1990
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Functional Neuromuscular Stimulation for Paraplegic Standing
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 1~4
An implementation scheme of the magnetic nerve stimulator using a switching mode power supply is proposed. By using a switching mode power supply rather than a conventional linear power supply for charging high voltage capacitors, the weight and size of the magnetic nerve stimulator can be considerably reduced. Maximum output voltage of the developed magnetic nerve stimulator using the switching mode power supply is 3,000 volts and switching time is about 100 msec. Experimental results or human nerve stimulations using the developed stimulator are presented.
Bioactivity of Calcium Phosphate Ceramic Coatings on Metallic Implants
Kim, Cheol-Sang ; Ducheyne, P. ;
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 5~12
Calcium phosphate ceramics have been applied intensively to orthopaedic and dental implants by virtue of their osteoconductive nature. In an attempt to enhance the bone implant intergrity and Eta utility, these ceramics are deposited onto the porous surface of metallic implants. The coating procedure and the ensuing phase transformations of the ceramic alter the mechanical properties and surface chemistry of the ceramic layers as well as those of the substrate. These structural and compositional differences are directly related to the interaction mechanisms at the surface-active ceramicbone interface. Material and processing induced influences on dissolution, electrokinetic behavior, ceramic-metallic substrate interface and boRe growth enhancement are presented.
Frequency Responses of Ambulatory ECG Systems and Their Correction by a Compensation Circuit
Iwao, K. ; Yokoi, A. ; Suzuki, S. ; Goto, T. ; Doniwa, K. ; Okajima, M. ;
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 13~18
Frequency responses of ambulatory electrocardiogram systems were measured. Phase shift was assessed by our improved Wagner's method. The characteristics of the systems were found much worse than that of ordinary ECG equipment both in gain and phase responses. The decay of -3dB in amplitude observed in 0.2Hz and the lead of 45 dog in phase was observed in 0.6Hz. In order to investigate which of these 2 responses play major role in generating false S -T deviation, mathe- matical filters were Composed in a computer and actual ECGs were fed. The false S-T deviation were found to be caused mostly by enormous lead in phase, and then, the compensation circuit to diminish the lead in phase was inserted in the commercial systemes. The compensated systems showed no false deviation in S-T segment.
The Study of Possibility of Cancer Diagnosis by the Spectral Analysis of Excretion of Human Urine
Kim, Yong-Jin ;
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 19~24
A simple diffraction grating spectrometer is successfully utilized to distinguish the similar red colored sediments obstained from both of cancer and non-cancer urine reactions caused by the the previous developed reagent for the cancer diagnosis by examining their spectral absorption bands in order to improve its sensitivity and specficity. It is found that the cancer and non-cancer absorp- tion band regions lie between 4250 A and 4750 A and between 5250 A and 5400 A, respectively.
A Study on the LQG/LTR Method
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 25~30
In this paper a new approximation method is presented for the nonminimum phase problem of LQG/LTR. Theoretical analysis and simulation results show that it can be better approximated than Stein's method.
Correction of Ocular Fundus Fluorescein Angiogram in Nonlinear Distortion
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 31~38
Image correction of the fluorescein angiogram with the low contrast and geometrically distorted is studied. The procedure is divided into two steps : A template matching step and a geometrical transformation step. Based on the sequential similiarity detection algorithm, more Improved matching results are obtained with edge enhanced image. For the reference points and the corresponding matchimg points, the geometrical transformationss by the use of the average value of the X, Y translational shifts and a pair of these points, respectively are described. Then the corrected images are obtained using bilinear interpolation. It is proven that the usefullness of this study for the image correction of the ocular fundus fluoresceln angiogram with low contrast and geometrically distorted mainly due to the eye movements
Development of Isokinetic Exercise System and Examination of Its Performance
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 39~46
An isokinetic exercise system was designed and manufactured to perform muscular performance test and the traning of athletes and the rehabilitation of patients. The system majorly consists of gear box, D. C servo motor and servo controller, data reduction computer. Preliminary experiments were conducted to find out the performance of the system. The performance of the prototype isokinetic exercise system was turned out to be satisfactory compared with a commercial product called CYBEX system.
Synthesis and Biocompatibility of Graft Copolymer of Butyl Methacrylate onto Gelatin
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 47~56
The grafting of butyl methacrylate onto gelatin was investigated by potassium persulfate(KPS) redox system in aqueous solution. The optimum conditions of grafting were observed, and the physical property and the biocolnpatibility of graft copolymer membrane were examined. The gas permeability and the biodegradation by bacteria were decreased with the grafting percentage increased, and tensile strength increased with the grafting percentage increased.
A Study on the Development of the Portable Intelligent QT Analyzer
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 57~64
This study describes the design of the portable intelligent QT analyzer which can record and analyze the ambulatory ECG data. System hardware is consisted of the one chip microcomputer(80C31) , A/D, ROM, RAM, LCD display and preamplifier. ECG data were processed by the differentiator and the digital filter. The de- tection of the parameters-QT, QTP and RR interval-was accomplished by the software algorithm using the slope and the amplitude of the processed data. Using this system, the trends of the parameters obtained during the long term could be observed.
Estimation of Evoked Potentials by Object Color Stimulation
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 65~70
The phenomenon of color sensory has been mainly studied on the relation with the stimulus source of light source color according to dispersed energy of light. However, it has not been definitely found that the phenomenon of color sensory be collcerned with evoked potentials stimulated by object color. This paper proposes the method that evoked potentials stimulated by object colors are analyzed and examined on the phenomemon of color sensory. The model of evoked potentials is assumed that it is consisted of an additive noise and a transient signal caused by stimulus. The method which is used to estimate the signal is time-varying filtering.
Shape-based Interpolation Algorithm of CT Image
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 71~74
In the medical modalities, three-dimensional objects must be reconstructed from the consecutive slices. but the slime separation is usually much greater than the pixel size within an individual slices. In this paper, an interpolation scheme for filling the spare between the shapes in two successive slices is developed. It minimizes the computation involvement in segmentation of 3-D reconst ructlon process as well as more accurately approximates the object than the linear interpolation method.
A study on the Visible Speech Processing System for the Hearing Impaired
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 75~82
The purpose of this study is to help the hearing Impaired's speech training with a visible speech processing system. In brief, this system converts the features of speech signals into graphics on monitor, and adjusts the features of hearing impaired to normal ones. There are formant and pitch in the features used for this system. They are extracted using the digital signal processing such as linear predictive method or AMDF(Average Magnitude Difference Function). In order to effectively train for the hearing impaired's abnormal speech, easilly visible feature has been being studied.
A Neural Speech Processing Algorithm for Multielectrode Cochlear Implant System
Choi, Jin-Young ; Cho, Jin-Ho ; Lee, Kuhn-Il ;
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 83~88
A New speech processing algorithm using neural networks is proposed. We transform input data into frequency domain and process them by neural networks of 22 output neurons which have Bark scale on the ground that the Bark scale is similiar with that of the characteristics of human cochlea. An utilized neural network is multilayer perceptron, and the characteristics of cochlea have it trained by error back propagation learning algorithm. The trained neural networks suffices functions of human cochlea including the effects of automatic gain control, compression and equalization. Simulation results show that the proposed speech processing algorithm has good performance in automatic gain control, compression and equalization.
Error Analysis in the Numerical Solution of Rayleigh Integral
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 89~96
The numerical evaluation of Rayleigh's integral for the sound source reconstruction can be speeded up by the use of angular frequency propagation method and the FFT. However, are several source of errors involved during the reconstruction. Besides the aliasing error due to undersampling in space, the wrap around error. which is caused by undersampling the kernel functionin frequency domain, and windowing effect are present. We found that there is no replicated source problem and the windowing effect is due to the windowing the kernel function In frequency domain, and, xero padding is always required to improve the quality of reconstruction.
Algin Impregnated Vascular Graft I. In Vitro Investigation
Lee, Jin-Ho ; Shin, Bung-Chul ; Khang, Gil-Son ; Lee, Hai-Bang ;
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 97~104
Microvel double velour graft impregnated with a biodegradable algin was studied as a new vascular graft. It is blood tight but still retains high porosity. Thls graft does not need to be preslotted with blood before implantation and has good tissue ingrowth and biological healing properties. The algin impregnated vascular graft was investigated by "in vitro" tests in this study. It was characterl zed by ESCA analysis, SEM observation, and measurements of water permeability, algin coating weight, mechanical properties and whole blood clotting time. The water permeability of the graft was reduced more than 99% and the whole blood clotting time was fast more than three times by the algin impregnation treatment. "In vivo" performance examinations of the algin impregnated graft are on progress.aft are on progress.
The Design of a "Motorized Wheelchair(INMEL-5)" for Loading in the Car
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 105~112
The main concepts in the design and construction of an motorized wheelchair for loading in the tar which is intended to drive a disabled to long distance. The wheelchair is basically a powered and folding, so it is designed to motorized manual wheel- chair by modularity method. The wheelchair hrs been installed with a power motor module, battery module, and drive & control module. The goal of this project is to develop a wheelchair that has multifunction and operated disabled who has variety impairment. So we ave currently working. Experimental results of the system approach our purpose, which is improved maneuverability, safety and can be loaded.
Resolution Enhancement of Ultrasonic B-scan Images by Modified Wiener Filter
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 113~120
In this paper, the deconvolution method utilizing a modified Wiener filter is applied for the enhancement of lateral resolution of ultrasonic B-scan Images. For this purpose, a phantom composed of wires which are 0.6mm of diameter and apart in the range between 3 to 9mm is constructed. The modified Wiener filter with optimal parameter is applied to the phantom for the analysis of ultrasonic image. The results obtained are as follows'When all parameters of the modified Wiener filter are optimal, the resolution of B-scan images is enhanced by 50 percent : Othenrise, the images are blurred, spilt at peak points, or noises are strengthened severely. When the point-spread function representing the characteristic function of the system is determined, the selection ranges of op- timum parameters may be narrowed. It is expected that the proposed method may be able to apply to clinic situations for more accurate image analysis by means of reducing the loss of important information.
Estimation of Ultrasound Attenuation Coefficients with Nonlinear Frequency Dependency for Human Liver
Lee, No-Sung ; Woo, Kwang-Bang ; Yu, Hyung-Shik ;
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 121~130
In this study, the coefficients of ultrasound attenuation for human liver were determined in 6 normal humans and in 38 patients with diffuse liver disease. The coefficients with linear frequency dependency as well as nonlinear frequency dependency were evaluated. Gaussian pulse propagating in a lossy medium suffers downshifting of a center frequency and decreasing in the bandwidth. Such changes in frequency domain spectrum were quantified in terms of changes in the attenuation coefficients with nonlinear dependency, which in turn improve clinical Implications of the coefficients. Statistical analysis shows that the attenuation coefficients evaluated with nonlinear dependency reflect an improved accuracy for the diffuse liver disease than those with linear dependency. The discriminant analysis also indicate the improved classification with nonlinear dependency(75%) than with linear dependency(61%).
Evaluation of Endothelial Cell Attachment on Polymer Surface
Choi, Jin-Wook ; Ryu, Gyu-Ha ; Min, Byoung-Goo ;
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 131~140
To improve antithrombogenicity of polymer that used in vascular graft and artificial organs, seeding of human endothelial cells on the polyurethane was studied. Human endothelial cells were ismlated from human umbilical veins, using type I collagenase, and identified with goat anti vWF antibodies. Human endothilial cell seeding was tried upon the polyurethane which has good mechanical property and resists stresses. The hydrophobic polyurethane surface was changed hydrophilic by corona discharf:e treatment. Surface hydrophilicity was measured with Wilhemly plate method and the goniometer. To evaluate matrix protein adsorption, fibronectin adsorption test was done. To eveluate cell adhesion, human endothelial cell attachment forces were measured rising a perfusion chamber of , ism diamter. Less cells were detached from the hydrophilically treated polyurethane. This showed that corona discharge on the polyurethane could improve matrix adsorption and endothelial cell attachment.
A Study on the Development of Clinical Workstation
Park, Kwang-Seok ; Lee, Tae-Su ; Min, Byeong-Gu ;
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 141~146
A clinical workstation has been developed for the use in clinical ward. This system is connected to the Picture Archiving and Communication System previously installed. It provides the capabilities of image display, image processing, diagnostic report review, clinical lab data review and analytic diagrams presentation for the hospitalized patients in clinical ward. The performances of this system were evaluated during the 9 months. These results show typical aspects of clinical patterns in data transmissions, image studies and clinical lab data studies. These typical aspects should be counted in the further development of workstation for the clinical use.
A study on the implementation simulation and system for 2-D doppler system using second-order sampling
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 147~156
A two-dimensional pulsed doppler system for ultrasonic blood velocity doppler signals is studied and implemented. The second-order sampling method and serial data processing procedures are utillized in the sys- tem, which eliminates the untuning problems at phase channels in the quadrature detection method as well as in the channels of parallel data processing. rho digital signal processor used in this system allows a hardware savings and flexible design options. The efficiency of the various mean frequency estimators in the second-order sampling system is examined by computer simulation as a function of the intersequence sample delay time. The temporal delay for the quadrature component is changed from
where to is the center frequency of the transducer, It is found that autocorrelator is the optimum frequency estimator for the second-order sampling: with !he intersequence sample delay of
. The qualitative variation and information proportional to blood velocity in the vessel system are obtained in the VIVO experiments.
A Study on Speech Recognition Using Auditory Model and Recurrent Network
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 157~162
In this study, a peripheral auditory model is used as a frequency feature extractor and a recurrent network which has recurrent links on input nodes is constructed in order to show the reliability of the recurrent network as a recognizer by executing recognition tests for 4 Korean place names and syllables. In the case of using the general learning rule, it is found that the weights are diverged for a long sequence because of the characteristics of the node function in the hidden and output layers. So, a refined weight compensation method is proposed and, using this method, it is possible to improve the system operation and to use long data. The recognition results are considerably good, even if time worping and endpoint detection are omitted and learning patterns and test patterns are made of average length of data. The recurrent network used in this study reflects well time information of temporal speech signal.
A Study on Performance Improvement of ECG Data Compression Algorithm
Lee, Byung-Chae ; Hwang, Seon-Cheol ; Lee, Myoung-Ho ;
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 163~170
In this paper, fast Fourier transform and fast Walsh transform algorithm are studied for ECG data compression. ECG data-12 bit samples digitized at 480 samples-are segmented into QRS complexes and 50 intervals by di%ital derivative filter, which used for detection of QS width and difrerenre compressed in Fourler or welsh domain. And also the existing techniques for data compression-TP, MTP, CORTES, AZTEC, MCORTES, which have not been evaluated with a common measurement of goodness, were processed to get absolute terms of values in the same condition.
A Study on Diagnosis Algorithm of Arrhythmia using Minnesota Code Criteria
Jeoung, Kee-Sam ; Shin, Kun-Soo ; Lee, Myoung-Ho ;
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 171~178
This paper describes a software algorithm for automatic diagnosis of arrhythmia using the criteria of Minnesota code manual. This algorithm provides more accurate and more objective information to medical doctor by standardizing the criteria of diagnosis of arrhythmia. Because this algorithm doesn't need complicated mathematic processing, it carries out the real-time automatic diagnosis that is very important in clinic. The Decision-Table technology suggests the proper results for the given conditions. So it can express clearly the complicated medical problems those are not solved by the mathematical methods. The Decision-Tables have very simple structure. Therefore, it is very easy to correct or expand the system by adding or correcting some rules.
Theoretical Study on the Dynamic Characteristics of Crutches
Journal of Biomedical Engineering Research, volume 11, issue 1, 1990, Pages 179~186
A numerical analysis of crutch walking cycle has been performed to determine the transmissibility of a single-degree-of-freedom crutch system when a non-harmonic periodic forcing function is acting on the spring-damping-mass system. The results indicate that the damping factor which can reduce the forces transmitted to the human body plays an important role. In crutch walking, the stride angle of dynamic crutches must be limited for the comfortable walking.