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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Biomedical Engineering Research
Journal Basic Information
Journal DOI :
The Korea Society of Medical and Biological Engineering
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Volume & Issues
Volume 23, Issue 6 - Dec 2002
Volume 23, Issue 5 - Nov 2002
Volume 23, Issue 4 - Aug 2002
Volume 23, Issue 3 - Jun 2002
Volume 23, Issue 2 - Apr 2002
Volume 23, Issue 1 - Feb 2002
Volume 24, Issue 6 - 00 2002
Selecting the target year
Design of Neural Network Based IEF Filter for Time-varying Control of Incremental Factor
Journal of Biomedical Engineering Research, volume 23, issue 5, 2002, Pages 333~340
Powerline interference in bioelectric recordings is a common source of noise. IEF(Incremental Estimation Filter) has been used to eliminate powerline interferences in biosignals, especially in ECG(Electrocadiogram) signals. The constant incremental factor in the IEF filter, which affects the performance of noise rejection, is usually determined empirically or experimentally based on the input signals. This paper presents the design of neural network based IEF filter for time-varying control of the incremental factor. The proposed IEF filter is evaluated by applying to artificial signals as well as ECG signals of MIT-BIH database. For the relative comparison of noise-rejection performance, it is compared with adaptive noise canceler and conventional IEF filter. Simulation results show that the neural network based IEF filter outperforms these adaptive filters with respect to convergence speed and noise rejection is specific frequencies.
Development of Target-Controlled Infusion System in Plasma Concentration. PART1 : Establishment of Pharmacokinetic Model and Verification
Journal of Biomedical Engineering Research, volume 23, issue 5, 2002, Pages 341~349
The target controlled infusion(TCI) pump system is a logical approach to the development of improved administration techniques of an intravenous anaesthetic agent. The principle of TCI system is based on an understanding of the pharmacokinetic properties, three or four compartment model. The TCI system is optimal and flexible control of the plasma drug concentration. But the clinical goal is always to achieve a therapeutic drug effect, not a therapeutic concentration. So we developed the algorithm to target the concentration at the site of drug effect rather than the concentration in the plasma. If impulse drug is inputted into body, the decline of plasma concentration with time is shown, resulting in the expression of the differential equation. Therefore, we must reformulate our three-compartment model as four-compartment model with the effect compartment. And we tested plasma targeting and effect targeting algorithm by computer simulation using four-compartment model. So we developed the TCI capable of applying all intravenous drugs by adjusting individual pharmacokinetic parameters independently.
Real-Time 3-D Ultrasound Imaging Method using a 2-D Curved Array
Journal of Biomedical Engineering Research, volume 23, issue 5, 2002, Pages 351~364
Conventional 3D ultrasound imaging using mechanical ID arrays suffers from poor elevation resolution due to the limited depth-of-focus (DOF). On the other hand, 3D imaging systems using 2D phased arrays have a large number of active channels and hence require a very expensive and bulky beamforming hardware. To overcome these limitations, a new real-time volumetric imaging method using curved 2-D arrays is presented, in which a small subaperture, consisting of 256 elements, moves across the array surface to scan a volume of interest. For this purpose, a 2-D curved array is designed which consists of 90
46 elements with 1.5λ inter-element spacing and has the same view angles along both the lateral and elevation directions as those of a commercial mechanical 1-D array. In the proposed method, transmit and receive subapertures are constructed by cutting the four corners of a rectangular aperture to obtain a required image qualify with a small number of active channels. In addition the receive subaperture size is increased by using a sparse array scheme that uses every other elements in both directions. To suppress the grating lobes elevated due to the increase in clement spacing, fold-over array scheme is adopted in transmit, which doubles the effective size of a transmit aperture in each direction. Computer simulation results show that the proposed method can provide almost the same and greatly improved resolutions in the lateral and elevation directions, respectively compared with the conventional 3D imaging with a mechanical 1-D array.
Simulation Study for the Distortion Correction of Digital Angiographic Images using Geometric Transformation
Journal of Biomedical Engineering Research, volume 23, issue 5, 2002, Pages 365~373
Accurate localization of target lesion is required to protect normal peripheral tissue and irradiate exactly to tumors in stereotactic radiosurgery(SRS). Digital angiography is one of the most effective diagnostic tools to detect and identify the target tumors. However, it shows pincushion distortion due to the characteristics of the image intensifier. We have implemented a simulation study for the correction of distortion using the geometric transformation. Phantom images were produced transformation. In conclusion, the geometric transformation could effectively be used for the pincushion distortion of image intensifier and there was no significant different between two methods indicating 2% correction error from the ideal image in all cases.
The Change of Flow Characteristics in Lateral Aneurysm Models for Different Coil Locations
Journal of Biomedical Engineering Research, volume 23, issue 5, 2002, Pages 375~383
Aneurysm embolisation method using coils have been widely used. Micro coils are introduced via a small catheter, and are packed inside of aneurysm sac, which induces intraaneurysmal flow stagnation and thrombus formation. When partial blocking of an aneurysm is inevitable, the location of coils is important since it changes the flow patterns inside the aneurysm, which affect the embolisation process. We measured the flow field inside the partially blocked lateral aneurysm models in vitro, and tried to suggest the effective locations of coils for aneurysm embolisation. Velocity fields are measured using a particle image velocitimeter for different coil locations- proximal neck, distal neck, proximal dome and distal dome. Flow into the aneurysm sac was significantly reduced in the distally blocked models, and coils at distal neck blocked inflow more effectively comparing to those at distal dome. This study suggests that distal neck should be the most effective location for aneurysm embolisation.
Development of a Vertebral Fusion Device and Its Mechanical Analysis using 3-D Finite Element Method
Journal of Biomedical Engineering Research, volume 23, issue 5, 2002, Pages 385~390
Nowadays, there are many attempts to develop domestic medical-equipments. In this study, it is performed to developed a new vertebral fusion device. The basic models are a rectangular-frame type and a screw type which are generally used for the patients. The main purpose of the development of a new device is to reduce the amount of bone taken out for the insertion of a device to vertebral disc and this paper is focused on th concept of a new device shape. In the results, two types are devised. One is a folding type and the other is a separate-push-in type device both are in primitive stage. However, in a folding type there are mechanical pins and the analysis of pins and the lock system is still in study and needs some time. Therefore a separate-push-in type is introduced in this study mainly and a prototype and 3-D finite element model are made and experimented and stress analyzed. From the results it is considered that it is stable for the basic loading condition of vertebra, however, it is required to develop a supporting operational equipment for the convenience of the operation in practice.
Changes in The Pressure-Flow Control Characteristics of Shunt Valves by Intracranial Pressure Pulsation
Journal of Biomedical Engineering Research, volume 23, issue 5, 2002, Pages 391~395
Shunt valves used to treat patient with hydrocephalus were numerically simulated to investigate influence of pressure pulsation on their flow control characteristics. We modeled flow orifice through the shunt valve and imposed pulsating pressure and valve diaphragm movement to compute flow through the valve. The results of our study indicated that flow rates increased more than 40% by introducing pressure pulsation and diaphragm movement on the shunt valve. Our results demonstrate the pressure-flow control characteristics of shunt valves implanted above human brain may be quite different from those obtained by syringe pump test just after manufacture that induces uniform pressure.
Development of an Portable Urine Glucose Monitoring System
Journal of Biomedical Engineering Research, volume 23, issue 5, 2002, Pages 397~403
Urine glucose monitoring system is a self-monitoring system that display the glucose level by non-invasive measurement method. In this paper, We developed a noninvasive urine glucose monitoring system that improved defects of urine glucose measurement with a colorimeter method and invasive blood glucose measurement method. This system consist of bio-chemical sensor for urine glucose measurements, signal detecting part, digital and signal analysis part, display part and power supplying part. The developed bio-chemical sensor for the measurement of urine glucose has good reproducibility, convenience of handing and can be mass-produced with cheap price. To evaluate the performance of the developed system, We performed the evaluation of confidence about the detection of glucose level by a comparison between a standard instrument in measuring glucose level and the developed system using standard glucose solutions mixed with urine. Standard error was 2.85282 from the evaluation of confidence based on regression analysis. Also, In analysis of S.D(standard deviation) and C.V(coefficient of validation) that are important parameters to evaluate system using bio-chemical sensor, S.D was 10% which falls under clinically valid value, 15%, and C.V was under 5%. Consequently from the above results, compared to blood glucose measurement, the system performance is satisfactory.
Analysis of Meridians Potential Change for Meridians State Diagnosis
Journal of Biomedical Engineering Research, volume 23, issue 5, 2002, Pages 405~412
The principle of Acupuncture effect on meridians is what physical stimulation does on general physiology so that is gets into new equilibrium from the fallen function state of human body. However, in western medicine, it is generally accepted that the action passageway of various kinds stimulation has been regarded as nerve-endocrine-immune system. Acupuncture effect has been regarded any action for all meridians as a respones by the stimulation. Western medicine doesn's accept treatment for transmission of the bio-energy. In this paper, we compared change of electric potential when an acupuncturist's bio-energy is passed on and when is not. As a result of clinics, the acupuncture effect is different as acupuncture method, when an acupuncturist's bio-energy is passed on the meridian and it isn's. It implies that acupuncture effect can complicately respond by simple acupuncture stimulus and transmission of bio-energy, on same meridian. We could confirm the relationship between an acupuncturist's energy transmission and acupuncture effect. Therefore, we could diagnosis the state of meridian using change of electric potential on the same meridian.
Development of Bioelectrical Impedance Analyzer for Korean in Telemedicine
Journal of Biomedical Engineering Research, volume 23, issue 5, 2002, Pages 413~418
The purpose of this study was to design a single frequency BIA(Bioelectrical Impedance Analyzer) which can measure body impedance when patient is sitting on the toilet and to develope a prediction equation for designed BIA. For the purpose of this study, we acquired body impedances with designed BIA from 181 subjects composed of healthy Korean by attaching electrodes to suitable positions(wrist and thigh) for toilet measurement. We computed an appropriate FFM(Fat Free Mass) for Korean using modified-Siri equation to the same subjects instead of Siri equation which nay cause accuracy problems in hydrodensitometry when it applied to Korean. We used this FFM as reference value and developed a Korean FFM prediction equation based on body impedance index, body weight and sex. Correlation coefficient between prediction value and reference value of FFM was extremely high (r = 0.977) and SEE(Standard Error of Estimation) was low 2.47kg.(p<0.05) For comparison between existing electrode-attaching method and our method for toilet measurement, we acquired body impedance with designed BIA from same subjects attaching electrodes on existing positions (wrist and ankle) and made FFM prediction equation for BIA. Correlation coeffient between predicted value and reference value was 0.978 and SEE was 2.43kg(p<0.05). It means that the developed system has not significant differences with existing method. In conclusion bioelectrical impedance analyzer and the FFM prediction equation developed in this paper are evaluated to he adequate to compute FFM of Korean.