• Journal of Biomedical Engineering Research
• /
• v.4 no.1
• /
• pp.29-36
• /
• 1983

In this paper, center frequency down slift of ultrasonic echo signals which for the measurements of frequency dependent attenuation in the biological tissue are estimated. Center frequency down shift of echo-signals are estimated after signal spectrum analysis of whole echo-signals. In case of signal spectrums are simple, estimation of down shift frequency is very simple and in case of complicate spectrum, estimation of down shift frequency is depend on spectral shape. In case of unable to estimate, frequency dependence of medium is nonlinear(n) 1), in which upper shift of spectrums are presented. In case of unable to estimate, spectrum analysis are performed at local position. At consquence, we know that spectral dispersions are caused complicately by biological tissue layer.

• Journal of Biomedical Engineering Research
• /
• v.7 no.2
• /
• pp.117-118
• /
• 1986

It is well known that nonlinear propagation characteristics of the wave in the tissue may give very useful information for the medical diagnoisis. In this paper, a new method to detect nonlinear propagation characteristics of the internal vibration in the tissue for the low frequency mechanical vibration by using bispectral analysis is proposed. In the method, low frequency vibration of f0( = 100Hz) is applied on the surface of the object, and the waveform of the internal vibration x (t) is measured from Doppler frequency modulation of silmultaneously transmitted probing ultrasonic waves. Then, the bispectra of the signal x (t) at the frequencies (f0, f0) and (f0, 2f0) are calculated to estimate the nonlinear propagation characteristics as their magnitude ratio, w here since bispectrum is free from the gaussian additive noise we can get the value with high S/N. Basic experimental system is constructed by using 3.0 MHz probing ultrasonic waves and the several experiments are carried out for some phantoms. Results show the superiority of the proposed method to the conventional method using power spectrum and also its usefulness for the tissue characterization.

• Proceedings of the KIEE Conference
• /
• 2006.10c
• /
• pp.148-150
• /
• 2006

In this paper, we propose a new method for detection of mass-type breast cancer in dense mammogram. As the proposed method analyzes texture of the breast tissue using method by fusing Homogeneity and Ranklets, improve problem of traditional method. Homogeneity gives the measure of uniform density, and Ranklets determine orientation selective property at vertical, horizontal and diagonal in mass region. The proposed method is suitable to dense mammogram with tangled normal tissue and cancer tissue. SVM(Support Vector Machine) classifier is used for effective detection of mass-type breast cancer in dense mammogram.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 1999.04a
• /
• pp.189.1-192
• /
• 1999

Mechanical characteristics of composite laminates with carbon tissue and glass scrim are evaluated in this paper. Composite laminates in USN125 group are made by inserting carbon tissue and glass scrim between layers. Consequently it was shown that mechanical characteristics of carbon fiber reinforced composite materials were improved by inserting carbon tissue.

• Proceedings of the Botanical Society of Korea Conference
• /
• 1999.07a
• /
• pp.1-9
• /
• 1999

Plant biotechnology including plant tissue culture is the most important science to rescue human beings from the crisis of biosphere of the earth which they will face in the 21st century. Global area other than Asia of trangenic crops increased more than 16 times from 1996 to 1998. In Asian countries, micropropagation using tissue culture techniques has been well developed and has contributed to agricultural production. Although researches on levels of laboratory and test field trial of transgenic crops have been performed actively in some Asian countries, areas of growing transgenic crops are still small in Asia countries except in China. In this paper, the status of plant biotechnology in global and Asian countries are reviewed and the future prospect of plant biotechnology in Asia and roles of Korean and Japanese plant scientists in it are discussed.

• Journal of electromagnetic engineering and science
• /
• v.10 no.4
• /
• pp.206-211
• /
• 2010

In this paper, an implantable planar inverted-F antenna (PIFA) for an artificial cardiac pacemaker is proposed. The antenna has a simple structure with a low profile and is placed on the top side of the pacemaker. The dimensions of the pacemaker system, including the antenna element, are $42{\times}43.6{\times}11$ mm. When the antenna is embedded in pig tissue, its $S_{11}$ value is -10.94 dB at 403 MHz and the -10 dB impedance bandwidth of the antenna is 6 MHz (399~406 MHz). The proposed PIFA in tissue has a peak gain of -20.19 dBi and a radiation efficiency of 1.12 % at 403 MHz. When the proposed antenna is placed in a flat phantom, its specific absorption ratio (SAR) value is 0.038 W/kg (1 g tissue). Performances of the proposed PIFA is sufficient to operate at the MICS band (402 ~ 405 MHz).

• The Journal of the Acoustical Society of Korea
• /
• v.29 no.1E
• /
• pp.1-10
• /
• 2010

The difference in echogenicity between cancerous and normal tissues is not quite distinguishable in ultrasound B-mode imaging. However, tumor or cancer in breast or prostate tends to be stiffer than the surrounding normal tissue. Thus, imaging the stiffness contrast between the two different tissue types is helpful for quantitative diagnosis, and such a method of imaging the elasticity of human tissue is collectively referred to as ultrasound elasticity imaging. Recently, elasticity imaging has established itself as an effective diagnostic modality in addition to ultrasound B-mode imaging. The purpose of this paper is to present various elasticity imaging methods that have been reported up to now and to describe their principles of operation and characteristics.

• Journal of Korean Foot and Ankle Society
• /
• v.25 no.2
• /
• pp.80-88
• /
• 2021

Chronic Achilles tendon rupture is likely to result in functional impairment in gait and sports activity. The presence of a large defect secondary to retraction of the tendon ends, atrophy of the calf muscles, and vulnerable vascularity of the soft tissue envelope make it a challenging problem to treat. Surgical reconstruction aims to restore the length and tension of the gastrocnemius-soleus complex. Various surgical treatment options have been described, depending on several factors, including residual gap size after scar tissue removal, remaining tissue quality, and vascularity. Despite good results being reported, there is a lack of high-level, evidence-based clinical guidelines available to select the first-line surgical procedure. This paper overviews the current available surgical options for patients with chronic Achilles tendon rupture.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2010.04a
• /
• pp.455-458
• /
• 2010

Extracting the brain from magnetic resonance imaging head scans is an essential preprocessing step of which the accuracy greatly affects subsequent image analysis. The currently popular Brain Extraction Tool produces a brain mask which may be too smooth for practical use to reduce the accuracy. This paper presents a novel and indirect brain extraction method based on non-brain tissue segmentation. Based on ITK, the proposed method allows a non-brain contour by using region growing to match with the original image naturally and extract the brain tissue. Experiments on two set of MRI data and 2D brain image in horizontal plane and 3D brain model indicate successful extraction of brain tissue from a head.

• Journal of Periodontal and Implant Science
• /
• v.41 no.6
• /
• pp.302-308
• /
• 2011

Purpose: The emergence profile concept of an implant restoration is one of the most important factors for the esthetics and health of peri-implant soft tissue. This paper reports on two cases of gingival recontouring by the fabrication of a provisional implant restoration to produce an optimal emergence profile of a definitive implant restoration. Methods: After the second surgery, a preliminary impression was taken to make a soft tissue working cast. A provisional crown was fabricated on the model. The soft tissue around the implant fixture on the model was trimmed with a laboratory scalpel to produce the scalloped gingival form. Light curing composite resin was added to fill the space between the provisional crown base and trimmed gingiva. After 4 to 6 weeks, the final impression was taken to make a definitive implant restoration, where the soft tissue and tooth form were in harmony with the adjacent tooth. Results: At the first insertion of the provisional restoration, gum bleaching revealed gingival pressure. Four to six weeks after placing the provisional restoration, the gum reformed with harmony between the peri-implant gingiva and adjacent dentition. Conclusions: Gingival recontouring with a provisional implant restoration is a non-surgical and non-procedure-sensitive method. The implant restoration with the optimal emergence profile is expected to provide superior esthetic and functional results.