• The Journal of the Acoustical Society of Korea
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• v.41 no.5
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• pp.534-544
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• 2022

Medical ultrasound system has been widely used to visualize the lesion for diagnostics in most medical service site including hospitals and clinics thanks to its advantages such as real time operation, ease of use, safety. Among many signal processing blocks of the system, one of the most important part that governs the image quality is the beamformer, and technologies for this part has been continuously developed in long time. The synthetic aperture imaging method, that is one of the major technologies of beamforming, was introduced to maximize utilizing the information delivered from the patient's body through the probe, and contributed to breakthrough of the image quality since it was introduced in around 1990's, and evolved continuously in decades. This paper reviews and surveys the process of development of this technology and expects future evolution.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.351-352
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• 2004

본 논문에서는 초음파 영상 진단기용 선형어레이 변환기를 장착할 수 있는 수조 와 128 채널의 스위칭 회로를 제작하여 변환기의 각 채널별 음향파워를 측정하였다. 실험은 128 채널 중 하나의 채널이 불량인 어레이 프로브를 대상으로 수행되었다. 측정 결과, 불량 채널의 음향 파워가 다른 채널에 비해 현저히 작게 나타남을 확인하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.754-756
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• 2005

본 논문은 연속 초음파 영상에서 움직임 보상 시간 필터를 적용하여 영상의 품질을 향상시키는 방법을 제안한다. 비선형 광학 흐름 추정 방법을 이용하여 화소 단위의 움직임을 추정하고, 이를 바탕으로 시간적 재귀 필터링을 적용한다 화소 단위 움직임 벡터의 양이 작을 경우 필터링을 크게 하고, 움직임 벡터의 양이 클 경우 필터링을 작게 적용한다. 그 결과 프로브에 의한 전역적 움직임과 측정 대상물에 의한 국부적 움직임으로 발생되는 블러 현상을 극소화하고 잡음을 감소시켜 영상의 품질을 향상시켰다.

• Journal of radiological science and technology
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• v.41 no.5
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• pp.427-435
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• 2018

There was a shortage of research reports on sterilization criterion and contamination of ultrasonic probes. Therefore, in this study, we were going to provide a basic study to measure the level of microbial contamination in ultrasonic probes and to investigate the radiographer's awareness of infection. After the scan, samples were collected from the rubber part of the probe by opening a sterile swab (Transport Medium AM608-1S) for medical bacteria collection with the remaining gel removed with a paper towel. Also, the collected samples of bacteria were grown for seven days and then the laboratory was analyzed. Among the total 29 types of microorganisms, Micrococcus luteus 21(26%), Moraxella species 16(20%), Coagulase negative staphylococcus 8(10%), Bacillus species 5(7%), Bicillus circulans 3(5%), Acinetobacter lwoffii 2(2%), and 1 other Candida parapsilosis (1%) a number of bacteria and fungus, was detected. In a disinfectant experiment using LuciPac Pen on the Lumitester PD-30s, we cultured the rubber part of the probe two to three times to measure the bacteria. Bacteria decreased to 97% with Aquanax (alkaline reduced water 100%), 99% with Klarion wash (0.01% sodium hydroxide), 94% with Klarion disinfection (0.01% nitrous acid water), Sterilization was best with Klarion wash (0.01% sodium hydroxide). Therefore, guidelines for cleaning and disinfection of ultrasonic probes was required, and further development of probe-only disinfectants is required.

• The Journal of the Acoustical Society of Korea
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• v.38 no.4
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• pp.443-449
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• 2019

To protect the patient's internal organs when a patient with cardiovascular disease occurs, it is important to reduce the elapsed time by providing emergency medical services. Decisions for conducting cardiopulmonary resuscitation are mainly made using the carotid palpation method, which directs the pulse of the carotid artery, which can diagnose the patient's condition according to one's own subject and cause cerebral blood flow to be blocked by excessive pressure in the carotid due to the weaken cardiopulmonary function. In this study, we developed a multimodal patch-type probe based on multi-channel ultrasound Doppler pairs and oxygen saturation measurement modules which can monitor cardiopulmonary functions. From the in-vivo experiments, the developed probe can be utilized as a novel tool that can increase the survival rate of cardiovascular disease patients by objectively monitoring the cardiopulmonary function of the patient quantitatively and promptly in an emergency situation.

• Journal of radiological science and technology
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• v.31 no.2
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• pp.161-169
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• 2008

Since measuring the size of kidney with sonography becomes an important index for diagnosis, treatment, and prognostic prediction in kidney disease, the accurate measurement and evaluation on this are clinically very important. Accordingly, the purpose of this study was to increase reproducibility and objectivity in measuring the size of kidney by enumerating factors that have an impact for measurement. It targeted 44 adults in Korea at the age of 21-27. It measured in order for both kidneys to be seen most largely while changing a subject-examiner's position in a state of fasting for 8 hours and a transducer's approaching direction. It compared a size of kidney by measuring, respectively, with the same method in 30 minutes and in 1 hour after drinking water in 700-1,000cc. In case of the lateral approach scan in decubitus position, the average length of the kidney both to the right and the left and the deviation of measurement to be the largest. In NPO(None Per Oral) state, the average length in the right kidney was 10.19cm, and the average length in the left kidney was 10.33cm. In 60 minutes after taking moisture, the average length in the right kidney was 10.94cm, and the average length in the left kidney was 11.13cm. In comparing the average length of the kidney in NPO state and its average length in 60 minutes after taking moisture, the size swelled by 7.3% for the length in the right kidney and by 7.7% in the left, thereby having been indicated to be statistically significant(P<0.003). The measurement in a size of kidney by using ultrasound may be measured differently depending on a patient's state of taking moisture and a transducer's approaching direction. It is thought that when the measurement in a size of kidney is especially important clinically, the intake and intake time in moisture need to be considered and that measuring with the posterior approach in prone position is a good method aiming to increase reproducibility in measuring length of the kidney.

• Journal of the Korea Convergence Society
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• v.9 no.4
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• pp.143-150
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• 2018

This work conducted the experimental analysis on ultrasonic acoustic matching in order to measure the accuracy of gaseous fuel level values. The experimental devices were used as 12V-DC supply, control T1 board, oscilloscope (DS01072B), ultrasonic probe and pattern table. The research models were designed by ceramic assay which can determine the transmitting and receiving energies. The result of the ringing area could verify the increased characteristics in the order of D (0.180m) < E (0.184m) < B (0.204m) < A (0.234m) < F (0.244m) < C (0.247m) models based on initial 2.9V of the maximum peak voltage. From the experimental results, the model designed by Ø21*3+2t of the matching layer was notable in that the most outstanding directivity energy could be created.

• The Journal of the Acoustical Society of Korea
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• v.27 no.5
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• pp.215-220
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• 2008

The kerfs between arrayed piezoelectric elements in a medical ultrasonic transducer or a piezoelectric composite transducer are generally filled by polymeric materials. The boundary condition of the elements for lateral mode vibration is changed according to the kerf-filling materials, so that the resonance frequency for longitudinal mode of the transducer is also varied. In this study, to investigate the resonance frequency variation for an arrayed transducer experimentally, the piezoelectric vibration elements of $14mm{\times}0.22mm{\times}0.44mm$ were fabricated and those were linearly arrayed. And, the resonance frequencies were measured for three cases of kerf-filling condition, non-filling and two different kinds of epoxy filling. Conclusively, it is confirmed that the resonant frequency variation shows the similar tendency with the theoretical one for the longitudinal mode.

• Journal of radiological science and technology
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• v.33 no.3
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• pp.245-252
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• 2010

This study analyzed speed of sound, impedance, attenuation coefficient in accordance with acoustic characteristic standard of body soft tissue corresponding with Annex DD of IEC standard 60601-2-37(2007) which is about tissue mimicking materials (TMM) synthesized by polyurethane as a main material and new type of n-type scatter materials. This study reached the following conclusion after analyzing and evaluating image characteristic with SONOACE 9900 c PRIME (MEDESON Co.) and brightness, maximum penetration with convex probe (2.5~5.0 MHz). When n-type scatter materials are increasingly synthesised 0~8% with prepolymer as a main material and polyol mixture as a catalyst, 1. The more scatter materials are increased, the more sound speed of TMM becomes closely similar to soft tissue. 2. The more scatter materials are decreased, the more acoustic impedance becomes closely similar to soft tissue. 3. The more scatter materials are increased, the more attenuation coefficient is increased. 4. The more scatter materials are increased, the more average brightness of images is increased, but there is threshold. 5. The maximum penetration becomes closely similar to soft tissue at the 6% TMM as a scatter material.

• Journal of the Korea Concrete Institute
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• v.29 no.3
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• pp.283-290
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• 2017

Various types of fibers are utilized in cementitious materials in order to improve their performances. Here, the extent of fiber dispersion is of key importance regardless of the purpose of using fiber. In this study, activated carbon fiber dispersion in mortar samples was evaluated using electrical resistivity method. In particular, the extent of fiber dispersion was compared per mixing methods and surface treatments. The results suggest that the surface resistivity method is capable of evaluating dispersion of activated carbon fiber and that ultrasound dispersion method is superior to mortar mixer and hand mixer method. The use of superplasticizer improved dispersion but acid treatment was not effective.