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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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Journal DOI :
The Korea Society of Medical and Biological Engineering
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Volume & Issues
Volume 15, Issue 4 - Dec 1994
Volume 15, Issue 3 - Sep 1994
Volume 15, Issue 2 - Jun 1994
Volume 15, Issue 1 - Mar 1994
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Chaotic Dynamics in EEG Signal Responding to Auditory Stimulus with Various Sound-Cutting Frequencies.
Choe, Jeong-Mi ; Bae, Byeong-Hun ; Kim, Su-Yong ;
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 237~244
We investigated the qualitive and quantitative properties in EEG signal which responds to auditory stimulus with increaing the sound-cutting frequency from 2 Hz to 20 Hz by 2 Hz step units, by chaotic dynamics. To bigin with, general chaotic properties such as fractal mechanism, 1 If frequency spectrum and positive Lyapunov exponent are discussed in EEG signal. For evoked potential with given auditory stimulus, the route to chaos by bifurcation diagram and the changes in geometrical property of Poincare sections of 2-dimensional psedophase space is observed. For that containing spontaneous potential, seen as the random background signal, the chaotic attractors in 3-dimensional phase space are found containing the same infomation as the above mentioned evoked potential. Finally the chinges of Lyapunov exponent by various sound-cutting frequencies of stimulus and by the various spatial positions (occipital region) in a brain surface to be measured, are illustrated meaningfully.
Development of Ultrasonic Image Management System
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 245~252
Three-Dimensional Flow Simulations of End-to-Side Vascular Anastomoses : Flow Dynamic Aspect on Preferential Development of Intimal Hyperplasia or Thrombosis
Kim, Young H. ; Krishnan B.Chandran ;
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 253~258
Three-dimensional steady and pulsatile flows in an end-to-side anastomosis were investigated using a finite difference method in order to understand the flow dynamics in the preferential development of distal anastomotic intimal hyperplasia or thrombosis. Steady flow results revealed that a double helical vortex was formed in the host artery and flow recirculations near toe find heel regions were restricted due to the secondary flow. Oscillating wall shear stress with significant secondary flow might be flow dynamic reason of developing intimal hyperplasia or thrombosis near the anastomotic region.
Modified Cellulose for Heparin Binder
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 259~264
Heparin binders (Cell-PALA) used for selective heparin removal from blood, were prepared by immobilizing a cationic polymer, poly(allylamine) (PALA), onto cellulose substrate by a novel method. Their absorbing capacity for heparin was compared with untreated cellulose control using heparin solution in vitro. The surface areas of obtained heparin binders and untreated cellulose were 1.36 and (
, respectively. The amount of bound heparin to PALA immobilized celluloses was determined to be 0.16 -
/cm, which is much higher than that of untreated cellulose (
). These results suggest that Cell-PALA materials can be utilized for a heparin removal system.
A Study on Optical Properties in Biological Tissue Using A Photon Path Diffusion Model
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 265~274
This paper proposes a method of noninvasive reflectance light to measure the blood fractional volume (Vb) and oxygen saturation (
) of biological tissue. We chose the red light of 660nm and infrared light of 880nm. In Vivo reflectance data were obtained by the physiological changes front the surface of the skin over the calf in human subject. The reflected light intensity from different layers within a biological tissue was measured by specially designed reflectometer to apply photon path diffusion model. The collected data represent the changes of blood (ractional volume and oxygen saturation at each reflected light wavelengths. The data evaluation was assessed by examining the slopes of the plotted indices for the changes in oxygen saturation and blood (ractional volume. The results presented in this paper claim that light reflectance can separately discriminate the change of blood volume and that of oxygenation in muscle and also in skin.
Estimation of Unknown Projection DATA Based on the Bandwidth of Projection DATA
Kil-Houm Park ;
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 275~280
In the case of the image reconstruction from unknown projection data such as imaging the object with opaque obstructions, conventional reconstruction algorithms may reconstruct a degraded image. In this paper, a new method for the estimation of the unknown projection data based on known projection data and the bandwidth of projection data is proposed. The proposed method successfully estimates the unknown projection data through iterative transformation between projection space and frequency space using the known projection data and the bandwidth of the projection data. Computer simulation shows that the proposed method significantly improves image quality and convergence behavior over conventional algorithms. In addition, the proposed method is successfully applied to ultrasound attenuation CT using a sponge phantom.
Decomposition of EMG Signal Using MAMDF Filtering and Digital Signal Processor
Lee, Jin ; Kim, Jong-Weon ; Kim, Sung-Hwan ;
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 281~288
In this paper, a new decomposition method of the interference EMG signal using MAMDF filtering and digital signal processor. The efficient software and hardware signal processing techniques are employed. The MAMDF filter is employed in order to estimate the presence and likely location of the respective templates which may include in the observed mixture, and high-resolution waveform alignment is employed in order to provide the optimal combination set and time delays of the selected templates. The TMS320C25 digital signal processor chip is employed in order to execute the intensive calculation part of the software. The method is verified through a simulation with real templates which are obtain ed from needle EMG. As a result, the proposed method provides an overall speed improvement of 32-40 times.
Development of a Modified Exoskeletal Linkage Type Instrument for 3-D Motion Measurement of the Human Knee Joint
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 289~294
A new type of electrogoniometer to measure the three dimensional motion of the human knee joint was developed. This instrument is composed of six potentiometers: four arranged for two universal joints, one for pin joint, and one for axial rotation measurement. The voltage change in six potentiometers were collected through A/D converter for acquisition, storage and analysis. With a developed instrument, gait analysis was performed. Compared to earlier developed triaxial type goniometer, new instrument shows its convenience in application and accuracy in measurement.
A Preliminary Study of the Transmission Dynamics of HIV Infection and AIDS
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 295~304
This paper describes some preliminary attempts to formulate simple mathematical models of the transmission dynamics of HIV infection in homosexual communities. In conjunction with a survey of the available epidemiological data on HIV infection and the incidence of AIDS, the model is used to assess how various processes influence the course of the initial epidemic following the introduction of the virus. Models of the early stages of viral spread provide crude methods for estimating the basic reproductive rate of the virus, given a knowledge of the incubation period of AIDS and the initial doubling time of the epidemic. More complex models are formulated to assess the influence of heterogeneity in sexual activity. This latter factor is shown to have a major effect on the predicted pattern of the epidemic.
A Study on the Identification of the EMG Signal in the Wavelet Transform Domain
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 305~316
All physical data in the real world are nonstationary signals that have the time varying statistical characteristics. Although few algorithms suitable to process the nonstationary signals have ever been suggested, these are treated the nonstationary signals under the assumption that the nonstationary signal is a piece-wise stationary signal. Recently, statistical analysis algorithms for the nonstationary signal have concentrated so much interest. In this paper, nonstationary EMG signals are mapped onto the orthogonal wavelet transform domain so that the eigenvalue spread of its autocorrelation matrix could be more smaller than that in the time domain. Then the model in the wavelet transform domain and an algorithm to estimate the model parameters are suggested. Also, an test signal generated by a white gaussian noise and the EMG signal are identified, and the algorithm performance is considered in the sense of the mean square error and the evaluation parameters.
A Study on the Implementation of the Multi-Process Structured ISDN Terminal Adaptor for Sending the Ultra Sound Medical Images
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 317~324
This paper proposed a new method in the implementation of ISDN (integrated services digital network) LAPD (link access procedure on the D-channel) and LAPB (link access procedure on the B-channel) protocols. The proposed method in this paper implement ISDW LAPD protocol through multi-tasking operating system and adopt a kernel part that is changed operating system to target board. The features of implemented system are (1) the para.llel processing of the events generated at each layer, as follows (2) the supporting necessary timers for the implementation of ISDW LAPD protocol from the kernel part by using software, (3) the recommanded SAP (Service Access Point) from CCITT was composed by using port function in the operating system. With the proposed method, the protocols of ISDH layerl, layer2 and layer3 (call control) were implemented by using the kernel part and related tests were carried out by connecting the ISDH terminal simulator to ISDN S-interface system using the ISDN LAPD protocol The results showed that ISDW S-interface terminals could be discriminated by TEI (Terminal Equipment Identifier) assignment in layer 2 (LAPD) and the message transmission of layer 3 was verified by establishing the multi-frame transmission and then through the path established by the LAPD protocol, a user data was tranfered and received on B-channel with LAPB protocol Thererfore, as new efficient ISDN S-interface environment was implemented in the thesis, it was verified that the implemented system can be utilized by connecting ISDW in the future to transfer a medical image data.
Automatic Detection of Left Ventricular Contour Using Hough Transform with Weighted Model from 2D Echocardiogram
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 325~332
In this paper, a method is proposed to detect the endocardial contour of the left ventricle using the Hough transform with a weighted model and edge information from the 2D echocardiogram. The implementation of this method is as follows: first, an approximate model detection algorithm was implemented in order to detect the approximate endocardium model and the model center, then we constructed a weighted model with the detected model. Next, we found automatically the cavity center of the left ventricle performing the Hough transform which used the weighted model, and then we detected the endocardial contour using weighted model and edge image.
Asan Medical Center Laboratory Information System (R) Information Communication System for Routine Hematology Using a Down-Sized Computer -
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 333~340
Laboratory information system (LIS) is a key tool to manage laboratory data in clinical pathology. Our department has developed an information system for routine hematology using down-sized computer system. We have used an IBM 486 compatible PC with 16 MB main memory, 210 MB hard disk drive, 9 RS-232C port and 24 pin dot printer The operating system and database management system were SCO UNIX and SCO foxbase, respectively. For program development, we used Xbase language provided by SCO foxbase. The C language was used for interface purpose. To make the system use friendly, pull-down menu was used. The system connected to our hospital information system via application program interface (API), so the information related to patient and request details is automatically transmitted to our computer. Our system interfaced with two complete blood count analyzers (Sysmex WE-8000 and Coulter STKS) for unidirectional data transmission from analyzer to computer. The authors suggests that this system based on down-sized computer could provide a progressive approach to total LIS based on local area network, and the implemented system could serve as a model for other hospital's LIS for routine hematology
Biodegradable Inorganic-Organic Composite Artiticial Bone Substitue -Part2. Collagen purification and its physical and biological properties-
Hwal Suh ;
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 341~346
To develop an artificial bone substitute that is gradually degraded and replaced by the regenerated natural bone, the authors designed a composite that is consisted of calcium phosphate and collagen. To use as the structural matrix of the composite, collagen was purified from human umbilical cord. The obtained collagen was treated by pepsin to remove telopeptides, and finally, the immune-free atel- ocollagen was produced. The cross linked atelocollagen was highly resistant to the collagenase induced collagenolysis. The cross linked collagen demonstrated an improved tensile strength.
Nonlinear Time Series Analysis of Biological Chaos
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 347~354
This paper describes a diagnostic protocol of nonlinear dynamic characteristics of biological system using chaos theory. An integrated chaos analysis system for the diagnosis of biological system was designed. We suggest a procedure of attractor reconstruction for reliable qualitative and quantitative analysis. The effect of autonomic nervous system activity on heart rate variability with power spectral analysis and its characteristics of chaotic attractors are investigated. The results show the applicability to evaluate the mental and physical conditions using nonlinear characteristics of biological signal.
A Study on Function Discrimination for EMG Signals Using Neural Network and Fuzzy Filter
Journal of Biomedical Engineering Research, volume 15, issue 3, 1994, Pages 355~364
The most important requirement for the controller of a prosthetic arm is that it has a high fidelity discriminator where the motion control may be performed open loop using EMG signals as a control source. Therefore, it is very effective method to reduce the influence of misclassification of classifier for the total system performance. This paper presents the new function discrimination method which combines MLP classifier and frizzy filter by stages for the requirement. The major advantage of MLP is a consistent learning capability for the easy adaptation to environments. The fuzzy filter uses all informations of MLP outputs and prior EMG activity informations which increase as the experience increases. That property is superior to one which uses maximum output of MLP in view of information amounts and quality. Simulation result shows that proposed method is superior to the probabilistic model, MLP model and the combined model of both in the respect of discrimination quaity.