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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 18, Issue 4 - Dec 1997
Volume 18, Issue 3 - Sep 1997
Volume 18, Issue 2 - Jun 1997
Volume 18, Issue 1 - Mar 1997
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An Evaluational Investigation of the Physical Properties for the Commercially Available Cervical Braces
Park, Jong-Chul ; Kim, Kyung-Tae ; Suh, Hwal ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 205~210
This is to investigate the physical properties of the commercially available Soft, Thomas, Minerva, and Philadelphia cervical braces which are widely used in orthopedics, neurosurgery, and rehabilitation medicine clinics as assisting devices for physical stabilization of cervical vertebrates, to use as a basic data for designing new type brace. Tensile strengths were observed by universal mechanical measuring device and Thomas brace required the highest stress to break by tensile stress. Durabilities against continuous frictional forces were also determined, and Minerva brace demonstrated the longest frictional time until being perforated. According to these results, poly ethlene is recommendable as a frame and preparation of pores in the material is favorable to provide ventilation to skin.
Estimation of Viscoelastic Properties of Trabecular Bone Using An Inverse Method
Kang, Shin-Ill ; Lee, Won-Hee ; Hong, Jung-Hwa ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 211~216
An inverse method with regularization has been developed to determine the viscoelastic properties of trabecular bone. A series of stress relaxation experiments were performed under the condition of uniaxial compression stress state. Optimization has been formulated within the framework of nonlinear least-squares and a modified Gauss-Newton method with a zeroth-order regularization technique. The stress relaxation behavior of trabecular bone was analyzed using a standard viscoelastic model. The present study clearly shows that trabecular bone exhibits typical viscoelastic stress relaxation behavior, and the obtained material parameters well represent the viscoelastic behavior of trabecular bone
Hydroxyapatite Coating on Ti Plate by a Dipping Method
Lee, Jun-Hui ; Kim, Seok-Yeong ; Kim, Yeong-Gon ; Lee, In-Seop ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 217~222
Hydroxyapatite(HA)-coated metal composites were made by the dipping method. The specimen substrates were Ti plates with a thickness of 2 mm. The HA coating was carried out in HA-sol for 1 min by the dipping method. The concentration of HA-sol for the coating ranged from 3.28 to 9.99 wt%. Excellent coating was observed on Ti substrate dipped once in 9.99 wt% sol. Preparation of Ti plates by sandblasting provided the better environment for coating HA on Ti surface than non-treated surface. As the concentration of sol increased, the weight change and the coating thickness increased. Above 7 wt% sol, they increased sharply.
Interframe Coding of 3-D Medical Image Using Warping Prediction
So, Yun-Sung ; Cho, Hyun-Duck ; Kim, Jong-Hyo ; Ra, Jong-Beom ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 223~231
In this paper, an interframe coding method for volumetric medical images is proposed. By treating interslice variations as the motion of bones or tissues, we use the motion compensation (MC) technique to predict the current frame from the previous frame. Instead of a block matching algorithm (BMA), which is the most common motion estimation (ME) algorithm in video coding, image warping with biolinear transformation has been suggested to predict complex interslice object variation in medical images. When an object disappears between slices, however, warping prediction has poor performance. In order to overcome this drawback, an overlapped block motion compensation (OBMC) technique is combined with carping prediction. Motion compensated residual images are then encoded by using an embedded zerotree wavelet (EZW) coder with small modification for consistent quality of reconstructed images. The experimental results show that the interframe coding suing warping prediction provides better performance compared with interframe coding, and the OBMC scheme gives some additional improvement over the warping-only MC method.
The Implementation of Hierarchical Artificial Neural Network Classifier for Chromosome Karyotype Classification
Jeon, Gye-Rok ; Choe, Uk-Hwan ; Nam, Gi-Gon ; Eom, Sang-Hui ; Lee, Gwon-Sun ; Jang, Yong-Hun ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 233~241
The research on chromosomes is very significant in cytogenetics since genes of the chromosomes control revelation of the inheritance plasma. The human chromosome analysis is widely used to study leukemia, malignancy, radiation hazard, and mutagen dosimetry as well as various congenital anomalies such as Down's, Klinefelter's, Edward's, and Patau's syndrome. The framing and analysis of the chromosome karyogram, which requires specific cytogenetic knowledge is most important in this field. Many researches on automated chromosome karyotype analysis methods have been carried out, some of which produced commercial systems. However, there still remains much room to improve the accuracy of chromosome classification and to reduce the processing time in real clinic environments. In this paper, we proposed a hierarchical artificial neural network(HANN) to classify the chromosome karyotype. We extracted three or four chromosome morphological feature parameters such as centromeric index, relative length ratio, relative area ratio, and chromosome length by preprocessing from ten human chromosome images. The feature parameters of five human chromosome images were used to learn HANN and the rest of them were used to classify the chromosome images. The experiment results show that the chromosome classification error is reduced much more than that of the other researchers using less feature parameters.
Flow Effects on Tailored RF Gradient Echo (TRFGE) Magnetic Resonance Imaging : In-flow and In-Plane Flow Effect
Mun, Chi-Ung ; Kim, Sang-Tae ; No, Yong-Man ; Im, Tae-Hwan ; Jo, Jang-Hui ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 243~251
In this paper, we have reported two interesting flow effects arising in the TRFGE sequence using water flow phantom. First, we have shown that the TRFGE sequence is indeed not affected by "in-flow" effect from the unsaturated spins flowing into the imaging slice. Second, the enhancement of "in-plane flow" signal in the readout gradient direction was observed when the TRFGE sequence was used without flow compensation. These two results have many interesting applications in MR imaging other than fMRI. Results obtained were also compared with the results obtained by the conventional gradient echo(CGE) imaging. Experiments were performed at 4.7T MRI/S animal system (Biospec, BRUKER, Switzerland). A cylindrical phantom was made using acryl and a vinyl tube was inserted at the center(Fig. 1). The whole cylinder was filled with water doped with
and the center tube was filled with saline which flows in parallel to the main magnetic field along the tube. Tailored RF pulse was designed to have quadratic (
) phase distribution in slice direction(z). Imaging parameters were TR/TE = 55~85/10msec, flip angle =
, slice thickness = 2mm, matrix size = 256
256, and FOV= 10cm. In-flow effect : Axial images were obtained with and without flow using the CGE and TRFGE sequences, respectively. The flow direction was perpendicular to the image slice. In-plane flow : Sagittal images were obtained with and without flow using the TRGE sequence. The readout gradient was applied in parallel to the flow direction. We have observed that the "in-flow" effect did not affect the TRFGE image, while "in-plane flow" running along the readout gradient direction enhanced the signal in the TRFGE sequence when flow compensation gradient scheme was not used.
Finite Element Analysis of the Artery and PTFE End-To-Side Anastomosis with 45
Han, Geun-Jo ; Kim, Hyeong-Tae ; An, Seong-Chan ; Sin, Jeong-Uk ; Kim, Yeong-Ho ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 253~259
Von Mises stress and compliance distribution was evaluated using a finite element analysis on the anastomosis of an artery with length of 20mm(z direction, along the horizental artery), inner diameter of 4mm, thickness fo 0.5mm and a PTFE graft with length of 5.7mm, inner diameter of 2mm, thickness of 0.2mm when anastomotic angle was
and inner pressure of 1330 dyne/mm2 was applied inside the 2 conduits. From the analysis results were obtained as follows. (1) Artery diameter increased in both horizontal x(along the length of artery) and vertical y(perpendicular to the length of artery)directions and the magnitude of that in x direction was bigger than that in y direction. (2) The compliance was maximum on the anastomosis, especially on that with acute angle. The reduction of compliance was observed from the anastomosis area to the either right or left end. (3) The equivalent stress was maximum on top in the y direction and minimum on the nodes apart
in circumferential direction from the top. (4) The equivalent stress was maximum in t도 vicinity of anastomosis with acute angle along the longitudinal direction of the artery. This trend was also observed along the PTFE graft.
SAR Pattern of Biological Objects Contacted with Coaxial Waveguide Antenna Using the FDTD Method
Koo, Sung-Mo ; Lee, Chang-Won ; Won, Chul-Ho ; Cho, Jin-Ho ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 261~266
Nonevasive multifrequency microwave radiometry using coaxial waveguide antenna has been investigated for a homogeneous and four layer human body model. The coupling between coaxial waveguide antenna and a biological object was analyzed by use of the finite-difference time-domain(FDTD) method to obtain the absorbed power patterns in the media. The object studied in this paper was a homogeneous and four-layered lossy medium. The specific absorption rates(SAR) distribution which was corresponding to the temperature distribution was calculated in each region by use of the steady-state response in FDTD method. The SAR pattern of 1.2GHz was compared with that of 1.8GHz.
A Study on the Energy and Time Characteristics of
Ju, Gwan-Sik ; Park, Il-Jin ; Kim, Jong-Ho ; Nam, Gi-Yong ; Baek, Seung-Hwa ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 267~272
he scintillation detector having
crystal with 3.6cm dia
2.0 cm thick was provided. The energy and timing characteristics were measured and compared with NaI(Tl) scintillation detectors, which widely used in unclear medicine. In order to measure the energy spectrum, the radioactive sources used were
and the source to detector distance was 7cm. For the timing characteristic, NaI(Tl)(1"
timing coincidence systems were prepared and the used source was
emitting 511keV annihilation photons. For the 511keV gamma-ray emitted from
, It was revealed that the timing response of the
detector was faster than NaI(Tl)(1"
1") and NaI(Tl)(3"
3") detector used in this experimental investigation. The energy characteristics of the
detector had a good values for about 500keV energy range.
Detection of Gastric Contraction in Electrogastrography: Spectrum Analysis and Vector Analysis
Kim, In-Young ; Han, Wan-Taek ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 273~283
Electrogastrography(EGG), the cutaneous recording of the myoelectrical activity of the stomach using surface electrodes, is attactive due to its non-invasiveness. Despite many attempts made over the decades, analysis of surface EGG has not led to identification of contraction-related electrical response activity of the stomach that would help the clinician to diagnose motility disorders of the stomach. We propose feasible methods to detect the gastric contraction by spectrum analysis and vector analysis of the surface EGG signal. A running spectral analysis(RSA) based on the fast Fourier transform (FFT) was applied to the filtered EGG signal. The powers of dominant frequency and its harmonics were compared with gastric contraction signals such as the strain gauge signal from the gastric serosa in dog or the antropyloric pressure in human. And we also carried out vector analysis of the filtered EGG signals obtained from three paired electrodes. The amplitude and direction of the calculated EGG vector were analyzed and compared with the gastric contraction signals. From the spectrum analysis, we found that the increase of the power of the first harmonic of the dominant frequency was highly correlated with the gastric contraction. And from the vector analysis of the EGG signal, we found a typical change of the amplitude and direction of the EGG vector, which can indicate occurrences of the gastric contraction.
A Study on the Characteristics of Heart Rate Variabilities In Nornal Subjects and Hemiplegic patients
Jeong, Kee-Sam ; Shin, Kun-Soo ; Lee, Jeong-Whan ; Ahn, Juhn ; Chon, Joong-Son ; Kim, Jun-Soo ; Lee, Myoung-Ho ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 285~290
In this paper, the power spectral analysis and the fractal analysis of heart rate variability(HRV) were performed to evaluate the effects of brain lesion on cardiovascular system and autonomic function for 24 normal subjects and 22 hemiplegic patients. The ECG and respiration signals were recorded at tilt angles of
for 5 and 6 minutes successively under the condition of frequency controlled respiration (0.25Hz). For normal subjects, HR, LF component, HF component and fractral dimension of HRV were distinctly changed after orthostatic stress, whereas, for hemiplegic patients, those were little changed. Complexity and variability of heart rate of patients were smaller than those of normal subjects. Sympathetic tone of patients was higher than that in normal subjects. All of these results support that autonomic disorder and cardiovascular disturbance accompanied by brain lesion could be assessed by the power spectral analysis and fractal analysis of HRV.
Design and Performance Evaluation of Small Size Counting and Imaging Gamma Probe System
Yang, Myo-Geun ; Kwark, Cheol-Eun ; Sim, yong-Geol ; Kim, Hee-Joung ; Choi, Yong ; Chung, Jung-Key ; Lee, Myung-Chul ; Koh, Chang-Soon ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 291~299
As a microimaging device detecting gamma rays emitted from small lesions or tumors during operation, the intraoperative surgical probe has been proposed and is now under development. We have designed a multipurpose portable gamma prove system and evaluated the performance both for the absolute counting purpose of residual radioactivities and for the localizing capability of gamma events using the NaI(Tl) crystal and two types of photomultiplier tubes(PMTs). Counting efficiencies in the range of routine clinical use of radiation dose were measured using the assembly of single channel PMTs and 0.5 inch thick NaI(Tl) crystal of 1 inch diameter. The positioning of gamma events for imaging purpose requires the multiple channel PMTs with appropriate positioning electronics. We have designed a simple and reliable positioning circuit based on the concept of modified Anger. In preliminary experiments using the multiple channel PMT of 3 inch diameter and the dim lighth source, we were able to trace and localize the correct position with reduced positioning error by the use of two multiplier/divider chipset and simplified peripherals. The energy resolutions for the counting gamma probe measured as full width at half maximum(FWHM) for Cs-137, F-18, Tc-99m were 12%, 13%, and 36%, respectively. The spatial resolution for the imaging gamma probe measured as FWHM for green LED was 2.9 mm. The results indicate that the currently developing probe is very promising and could be very useful for many applications in nuclear medicine. Future studies will include developing collimators, improving interface hardwares, and evaluating the system with clinical data.
Quantitative Evaluation of the Remaining Hepatic Function after Surgery in Patients with Hepatic Cancer using Deconvolution Technique of Tc-99m DISIDA SCAN
Kim, Deok-Won ; Kim, Su-Chan ; Yun, Seok-Jin ; Lee, Jong-Du ; Kim, Byeong-Ro ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 301~306
Surgical removal of hepatic cancerous tissues have been widely performed due to its early detection. However, a patient can not survive if excessive hepatic tissues were removed. Therefore, quantitative evaluation of remaining hepatic function after surgery is a really important factor for surgeon. the currently used ICG Rmax and Lidocaine clearance tests have disadvantages such as tedium, complexity, and inability to estimate remaining hepatic function after surgery. While HEF has advantages such as simplicity, quickness, nonivasiveness, and quantification, its reliability has been doubtful. Thus, the program for calculation of HEF has been developed from serial gamma camera image data. And we compared the reliability of HEF with ICG Rmax and Lidocaine clearance test using 6normal and 18 abnormal rabbits with damaged livers. The correlation coefficient of HEF to ICG Rmax and MEGX was 0.91, 0.94, respectively. I was also found that the HEFs of normal and abnormal hepatic tissues was higher than 100% and lower than 80%, respectively. Thus we confirmed that HEF can be a good indicator distinguishing between abnormal tissues and normal ones. Finally, we could conclude that patients would survive if both the pre-and the post-operative HEF were greater than 60%.
비정질 실리콘을 이용한 방사선 계측시 Photoconductive Gain의 특성
Lee, Hyeong-Gu ; Sin, Gyeong-Seop ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 307~313
he photoconductive gain mechanism in amorphus silicon devices was investigated in connection with applications to radiation detection. Various device types such as p-i-n, n-i-n and i-i-p-i-n structures were fabricated and tested. Photoconductive gain was measured in two time scales : one for short pulses of visible light(<
) which simulate the transit of energetic charged particles or
-rays, and the other for rather long pulses of light(1msec) which simulate x-ray exposure in medical imaging, We used two definitions of phtoconductive gain : current gain and charge gain which is an integration of the current gain. We obtained typical charge gains of 3~9 for short pulses and a few hundreds for long pulses at a dark current density level of 10mA/
. Various gain results are discussed in terms of the device structure, applied bias and dark current density.
A Study on the Development of Automatic Detection and Warning system while Drowsy Driving
Kim, Nam-Gyun ; Jeong, Gyeong-Ho ; Kim, Beop-Jung ;
Journal of Biomedical Engineering Research, volume 18, issue 3, 1997, Pages 315~323
Driving is a complex vigilance task that includes improper lookout, excessive speed and inattention. The primary objective of this research is to detect driver drowsiness so that the driver can be alerted to an impending traffic accident in performance. We developed the automatic detection and warning system during drowsy driving. A drowsiness detection system must be able to monitor driver status and detect the detrimental changes of a driver performance. Eyeblink has been found to be a reliable factor of drowsiness detection in earlier studies. As an additional parameter, we also considered the yawning which often occurs in a low vigilance state and predicts the drowsy state. We used a computer vision method to extract the eyeblink and yawning in the face image sequences. When the drowsy state was detected, the driver was refreshed by alarming device and menthol scent generator after deciding the warning level by fuzzy logic. For the evaluation of our system, we measured the physiological parameters such as EOG and EEG. The results indicated that it is possible to detect and alert the driver drowsiness temporarily or continuously by using our system.