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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 32, Issue 4 - Dec 2011
Volume 32, Issue 3 - Sep 2011
Volume 32, Issue 2 - Apr 2011
Volume 32, Issue 1 - Feb 2011
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A study on the Effects of Organism Vigor Information Solution to the Growth of Tumor-Derived Animal Cell
Jang, M.Y. ; Lee, K.S. ; Shin, J.W. ; Mun, C.W. ;
Journal of Biomedical Engineering Research, volume 32, issue 3, 2011, Pages 185~190
DOI : 10.9718/JBER.2011.32.3.185
The purpose of this study is to investigate the influence of organism vigor information solution(OVIS) on the animal cell growth and to set up a condition for cell culture. We investigated the reactions on the MG-63 and MCF-7 cell line in mixture culture media with various amount of REVIEW solution, which is an example among various OVIS. DMEM-HG was used as basic media. The concentration range of the mixture was limited from 0% to 15%. MTT assay is used for cell viability test. The cell was incubated for 14days and the MTT assay was performed on day 1, 3, 7, 10 and 14 throughout the experiment. We used the ELISA reader to measure the Optical Density(O.D) at 595 nm wavelength filter. MCF-7 was linearly proliferated according to culture time and concentrations of OVIS. On the other hand, MG-63 cells were measured the highest O.D value at 12%. The growth rates of both cells cultured in mixed culture media with OVIS are much higher than those in only basic media, DMEMHG, after 14days. It was confirmed that cell cultured at OVIS grows rapidly at certain period although cells showed a negative effect in initial stage.
Biomechanical Assessment of Lifting Chair with Hip-up Function
Bae, Ju-Hwan ; Moon, In-Huyk ;
Journal of Biomedical Engineering Research, volume 32, issue 3, 2011, Pages 191~197
DOI : 10.9718/JBER.2011.32.3.191
Lifting chair is a typical assistive product to aid for standing up and sitting down for persons with disability. It is particularly useful for the elderly persons whose muscular system is weakened by degenerative joint disease. This paper describes biomechanical assessments of lifting chair with hip-up function. In experiments we measured 3D motion and electromyographic(EMG) signal on the femoral muscle when subject performs the standing motion on the predetermined seat height. Based on assessment of the standing motion, we select the hip-up angle as 15 degrees to cover the relative femoral angle when EMG peak value is appeared. Using an implemented prototype lifting chair with hip-up function we perform standing experiments with five subjects. The experimental results show that the lifting and hip-up functions are effective to assist for standing up motion with less muscle force.
Objective Evaluation of Beamforming Techniques for Hearing Devices with Two-channel Microphone
Cho, Kyeong-Won ; Han, Jong-Hee ; Hong, Sung-Hwa ; Lee, Sang-Min ; Kim, Dong-Wook ; Kim, In-Young ; Kim, Sun-I. ;
Journal of Biomedical Engineering Research, volume 32, issue 3, 2011, Pages 198~206
DOI : 10.9718/JBER.2011.32.3.198
Hearing devices like cochlear implant, vibrant soundbridge, etc. try to offer better sound for people. In hearing devices, several beamformers including conventional directional microphone are applicable to noise reduction. Each beamformer has different directional response and it could change sound intelligibility or quality for listeners. Therefore, we investigated the performance of three beamformers, which are first and second order directional microphone, and broadband beamformer(BBF) with a computer simulation assuming hearing device microphone configuration. We also calculated objective measurements which have been used to evaluate speech enhancement algorithms. In the simulation, a single speech and a single babble noisewere propagated from the front and
azimuth degrees respectively. Microphones were configured in an end-fire array and the spacing was varied in comparison. With 3 cm spacing, BBF had about 3 dB higher enhanced SNR than that of directional microphones. However, enhancement of segmental SNR and frequency weighted segmental SNR were similar between the first order directional microphone and broadband beamformer. In addition when steady state noise was used, broadband beamformer showed the increased performance and had the highest enhanced SNR, and segmental SNR.
Automatic Switching System for The Impedance Analysis of Multichannel icroelectrode Arrays: Limits and Improvement Scheme
Lee, Seok-Young ; Nam, Yoon-Key ;
Journal of Biomedical Engineering Research, volume 32, issue 3, 2011, Pages 207~217
DOI : 10.9718/JBER.2011.32.3.207
Electrode impedances are measured to quantitatively characterize the electrode-electrolyte or cell-electrode interfaces. In the case of high-density microelectrode arrays(MEAs) that have been developed for brainmachine interface applications, the characterization process becomes a repeating and time-consuming task; a system that can perform the measurement and analysis in an automated fashion with accuracy and speed is required. However, due to the large number of channels, parasitic capacitance and off-capacitance components of the switching system become the major factors that decreased the accuracy for the measurement of high impedance microelectrodes. Here we investigated the implementation of automatic impedance measurement system with analyzing the causes of possible measurement-related problems in multichannel switching configuration. Based on our multi-channel measurement circuit model, we suggest solutions to the problems and introduce a novel impedance measurement scheme using electro-mechanical relays. The implemented measurement system could measure |Z| < 700
of impedance in - 10% errors, which can be widely applicable to high density neural recording MEAs.
A Study on the Performance of Companding Algorithms for Digital Hearing Aid Users
Hwang, Y.S. ; Han, J.H. ; Ji, Y.S. ; Hong, S.H. ; Lee, S.M. ; Kim, D.W. ; Kim, In-Young ; Kim, Sun-I. ;
Journal of Biomedical Engineering Research, volume 32, issue 3, 2011, Pages 218~229
DOI : 10.9718/JBER.2011.32.3.218
Companding algorithms have been used to enhance speech recognition in noise for cochlea implant users. The efficiency of using companding for digital hearing aid users is not yet validated. The purpose of this study is to evaluate the performance of the companding for digital hearing aid users in the various hearing loss cases. Using HeLPS, a hearing loss simulator, two different sensorinerual hearing loss conditions were simulated; mild gently sloping hearing loss(HL1) and moderate to steeply sloping hearing loss(HL2). In addition, a non-linear compression was simulated to compensate for hearing loss using national acoustic laboratories-non-linear version 1(NAL-NL1) in HeLPS. In companding, the following four different companding strategies were used changing Q values(q1, q2) of pre-filter(F filter) and post filter(G filter). Firstly, five IEEE sentences which were presented with speech-shaped noise at different SNRs(0, 5, 10, 15 dB) were processed by the companding. Secondly, the processed signals were applied to HeLPS. For comparison, signals which were not processed by companding were also applied to HeLPS. For the processed signals, log-likelihood ratio(LLR) and cepstral distance(CEP) were measured for evaluation of speech quality. Also, fourteen normal hearing listeners performed speech reception threshold(SRT) test for evaluation of speech intelligibility. As a result of this study, the processed signals with the companding and NAL-NL1 have performed better than that with only NAL-NL1 in the sensorineural hearing loss conditions. Moreover, the higher ratio of Q values showed better scores in LLR and CEP. In the SRT test, the processed signals with companding(SRT = -13.33 dB SPL) showed significantly better speech perception in noise than those processed using only NAL-NL1(SRT = -11.56 dB SPL).
Alteration of the Static Posture of Spine under Different Types and Amounts of Loading
Park, Yong-Hyun ; Kim, Young-Kwan ; Kim, Yoon-Hyuk ;
Journal of Biomedical Engineering Research, volume 32, issue 3, 2011, Pages 230~236
DOI : 10.9718/JBER.2011.32.3.230
The aim of this study was to investigate the alteration of lumbar spine and trunk postures on different load-carrying types and amounts under static loading. Two load-carrying types(unilateral carrying: UC vs. bilateral carrying: BC) and four different loads(0, 5, 10, and 15 kg) were randomly tested in this study. Carrying a heavy bag would affect human body posture, specifically lumbar spine curvature, which is considered as one of sources of back problems. Previous studies have not paid attention to the approach of the multisegment model of the lumbar spine and trunk. This study separated two compartments of trunk segment(the lumbar and thorax) in the analysis. The multisegment model of the lumbar spine in addition to Helen-Hayes marker set was used. Eight motion analysis cameras and a force plate were utilized. Ten male subjects(mean mass,
kg; mean height,
m) having no musculoskeletal disease participated in this study. We analyzed trunk angles in three anatomical planes and the spinal curvature in sagittal and frontal planes. Increased loading in both UC and BC significantly resulted in increases in trunk forward lean but only UC induced increases in trunk lateral lean. In addition, increased loading in BC produced flatten lumbar curvature in sagittal plane. As far as coupling motion, subjects tended to use axial rotation of the lumbar spine in transverse plane in response to increased UC loading. Finally, it is concluded that the increased static loading in UC rather than in BC tends to causes combined alterations of the spinal postures(sagittal and transverse planes together), which would be vulnerable to improper mechanical stresses on the spine.
Feature-based Non-rigid Registration between Pre- and Post-Contrast Lung CT Images
Lee, Hyun-Joon ; Hong, Young-Taek ; Shim, Hack-Joon ; Kwon, Dong-Jin ; Yun, Il-Dong ; Lee, Sang-Uk ; Kim, Nam-Kug ; Seo, Joon-Beom ;
Journal of Biomedical Engineering Research, volume 32, issue 3, 2011, Pages 237~244
DOI : 10.9718/JBER.2011.32.3.237
In this paper, a feature-based registration technique is proposed for pre-contrast and post-contrast lung CT images. It utilizes three dimensional(3-D) features with their descriptors and estimates feature correspondences by nearest neighborhood matching in the feature space. We design a transformation model between the input image pairs using a free form deformation(FFD) which is based on B-splines. Registration is achieved by minimizing an energy function incorporating the smoothness of FFD and the correspondence information through a non-linear gradient conjugate method. To deal with outliers in feature matching, our energy model integrates a robust estimator which discards outliers effectively by iteratively reducing a radius of confidence in the minimization process. Performance evaluation was carried out in terms of accuracy and efficiency using seven pairs of lung CT images of clinical practice. For a quantitative assessment, a radiologist specialized in thorax manually placed landmarks on each CT image pair. In comparative evaluation to a conventional feature-based registration method, our algorithm showed improved performances in both accuracy and efficiency.
Evaluation of MR-SENSE Reconstruction by Filtering Effect and Spatial Resolution of the Sensitivity Map for the Simulation-Based Linear Coil Array
Lee, D.H. ; Hong, C.P. ; Han, B.S. ; Kim, H.J. ; Suh, J.J. ; Kim, S.H. ; Lee, C.H. ; Lee, M.W. ;
Journal of Biomedical Engineering Research, volume 32, issue 3, 2011, Pages 245~250
DOI : 10.9718/JBER.2011.32.3.245
Parallel imaging technique can provide several advantages for a multitude of MRI applications. Especially, in SENSE technique, sensitivity maps were always required in order to determine the reconstruction matrix, therefore, a number of difference approaches using sensitivity information from coils have been demonstrated to improve of image quality. Moreover, many filtering methods were proposed such as adaptive matched filter and nonlinear diffusion technique to optimize the suppression of background noise and to improve of image quality. In this study, we performed SENSE reconstruction using computer simulations to confirm the most suitable method for the feasibility of filtering effect and according to changing order of polynomial fit that were applied on variation of spatial resolution of sensitivity map. The image was obtained at 0.32T(Magfinder II, Genpia, Korea) MRI system using spin-echo pulse sequence(TR/TE = 500/20 ms, FOV = 300 mm, matrix =
, thickness = 8 mm). For the simulation, obtained image was multiplied with four linear-array coil sensitivities which were formed of 2D-gaussian distribution and the image was complex white gaussian noise was added. Image processing was separated to apply two methods which were polynomial fitting and filtering according to spatial resolution of sensitivity map and each coil image was subsampled corresponding to reduction factor(r-factor) of 2 and 4. The results were compared to mean value of geomety factor(g-factor) and artifact power(AP) according to r-factor 2 and 4. Our results were represented while changing of spatial resolution of sensitivity map and r-factor, polynomial fit methods were represented the better results compared with general filtering methods. Although our result had limitation of computer simulation study instead of applying to experiment and coil geometric array such as linear, our method may be useful for determination of optimal sensitivity map in a linear coil array.
Development of a Smooth Colon Surface Restoration Method for Electronic Colon Cleansing
Kim, Seung-Hwan ; Kim, Dong-Sung ;
Journal of Biomedical Engineering Research, volume 32, issue 3, 2011, Pages 251~256
DOI : 10.9718/JBER.2011.32.3.251
Virtual colonoscopy is favored over conventional colonoscopy because its non-invasive procedure can avoid complications that may happen in a conventional approach and because it can cleanse colon electronically instead of uncomfortable conventional colon cleansing. Electronic Colon Cleansing(ECC) has to deal with not only removing tagged fecal material but also recovering Partial Volume Effect(PVE) due to tagging material. This paper proposes an ECC method restoring inherent natural PVE while previous approaches focused only on reducing PVE due to tagged fecal material. The proposed method reduces PVE using 3-dimensional adaptive density correction and then replaces tagged fecal material into air. Next, it generates natural PVE for the replaced air adjacent to soft tissue and finally makes smooth transition of gray values for soft tissue adjacent to the replaced air. The proposed method applied to eleven patient data, and showed promising results.
Quantitative Evaluation of Sparse-view CT Images Obtained with Iterative Image Reconstruction Methods
Kim, H.S. ; Gao, Jie ; Cho, M.H. ; Lee, S.Y. ;
Journal of Biomedical Engineering Research, volume 32, issue 3, 2011, Pages 257~263
DOI : 10.9718/JBER.2011.32.3.257
Sparse-view CT imaging is considered to be a solution to reduce x-ray dose of CT. Sparse-view CT imaging may have severe streak artifacts that could compromise the image qualities. We have compared quality of sparseview images reconstructed with two representative iterative reconstruction techniques, SIRT and TV-minimization, in terms of image error and edge preservation. In the comparison study, we have used the Shepp-Logan phantom image and real CT images obtained with a micro-CT. In both phantom image and real CT image tests, TV-minimization technique shows the best performance in error reduction and preserving edges. However, the excessive computation time of TV-minimization is a technical challenge for the practical use.
The Acoustic Output Estimation for Therapeutic Ultrasound Equipment using Electro-Acoustic Radiation Conductance
Yun, Yong-Hyeon ; Jho, Moon-Jae ; Kim, Yong-Tae ; Lee, Myoung-Ho ;
Journal of Biomedical Engineering Research, volume 32, issue 3, 2011, Pages 264~269
DOI : 10.9718/JBER.2011.32.3.264
To increase therapeutic efficiency and biological safety, it is important to precision control of acoustic output for therapeutic ultrasound equipment. In this paper, the electro-acoustic radiation conductance, one of electroacoustic characteristics of therapeutic ultrasound equipment, was measured by the radiation force balance method according to IEC 61161 standards and the acoustic output was estimated using the electro-acoustic radiation conductance. The estimation of acoustic output was conducted to continuous wave mode and pulse wave mode of duty cycle between 20% and 80%. The differences between prediction values and measurement results are within 5% of measurement uncertainty, which is a reasonably good agreement. The results show that acoustic output controlled by electro-acoustic radiation conductance was found to be an effective method.
Optical and Thermal Characteristic Studies of Cartilage by Laser Irradiation
Lee, Yeon-Ui ; Youn, Jong-In ;
Journal of Biomedical Engineering Research, volume 32, issue 3, 2011, Pages 270~277
DOI : 10.9718/JBER.2011.32.3.270
Laser cartilage reshaping(LCR) is a promising method for reshaping cartilage by using laser irradiation to maintain permanently modifies its shape. However this method has not been fully understood due to the limited scientific researches. The purpose of this study is to analyze optical and thermal characteristics of cartilage during laser irradiation. After analyzing Monte Carlo simulation for the comparison of laser fluence distributions with different laser wavelengths the characterization of the spectral changes during Nd:YAG laser(
= 1444 nm) irradiation was investigated in the ranges of 900-1700 nm with double integrating spheres. The surface temperature distribution changes during laser irradiation were investigated with an infrared camera. The quantitative measurements of optical and thermal characteristics in cartilage after laser irradiation were correlated with the transition of water flux(from bound to free water) and this study may be useful for better understanding of biophysical transformation phenomena in cartilage after laser heating.