• The Journal of the Acoustical Society of Korea
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• v.18 no.5
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• pp.83-90
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• 1999

In this paper, we studied resolution to the FBP and BFP image reconstruction algorithms for ultrasonic diffraction tomography. In order to analyze the resolution to the tomographic images which can be reconstructed from the modified FBP image reconstruction algorithm by using fixed coordinate system and BFP image reconstruction algorithm which is suitable for plane structure object, we derived ambiguity functions to these algorithms and then analyzed lateral and depth resolution through simulation respectively. Simulation results show that the lateral and depth resolution to the FBP image reconstruction algorithm and the BFP image reconstruction algorithm was determined 0.27 λ, 0.70 λ and 0.39 λ, 0.98 λ at the 3dB respectively. These results imply that modified FBP and BFP image reconstruction algorithms for diffraction tomography is useful in the tomographic image reconstruction.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.397-399
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• 2021

In this study, a basic study on the development of a multi-stimulation system was conducted to suppress lung cancer cell proliferation. Stimulation was applied to lung cancer cells using a photo-stimulating system and ultrasonic waves that generate a specific frequency, and the effect of inhibiting proliferation of cells was imaged and quantitatively evaluated. As a result of the experiment, when a single LED, single ultrasound stimulus were applied and ultrasound and LED stimuli were applied at the same time, meaningful results were shown in the proliferation rate of lung cancer cells.

• Journal of Biomedical Engineering Research
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• v.19 no.6
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• pp.571-575
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• 1998

One of the most significant features of diagnostic ultrasonic instruments is to provide real time information of the soft tissues movements. Echocardiogram has been widely used for diagnosis of heart diseases since it is able to show real time images of heart valves and walls. However, the currently used ultrasonic images are deteriorated due to presence of speckle noises and image dropout. Therefore, it is very important to develop a new technique which can enhance ultrasonic images. In this study, a technique which extracts enhanced binary images in echocardiograms was proposed. For this purpose, a digital moving image file was made from analog echocardiogram, then it was stored as 8-bit gray-level for each frame. For an efficient image processing, the region containing the heat septum and tricuspid valve was selected as the region of interest(ROI). Image enhancement filters and morphology filters were used to reduce speckle noises in the images. The proposed procedure in this paper resulted in binary images with enhanced contour compared to those form the conventional threshold technique and original image processing technique which can be further implemented for the quantitative analysis of the left ventricular wall motion in echocardiogram by easy detection of the heart wall contours.

• Journal of the Korea Institute of Building Construction
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• v.16 no.6
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• pp.587-594
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• 2016

This study aims to analyze the benefit-cost of the cleaning device for photovoltaic power generation systems in buildings in order to check its economic feasibility. A product, which has similar characteristics to the ultrasound-based cleaning device and is widely used in South Korea, was selected to compare with the benefit-cost value of the ultrasound-based cleaning device in this study. In order to quantitatively and qualitatively analyze benefit and cost aspects of the two products, categories and evaluation factors of each aspect as well as evaluation criteria were identified. Based on the identified evaluation factors and criteria, this study conducted face-to-face interviews with 15 experts to measure weights of benefit and cost aspects of the products. As the results, the total benefit weight of the ultrasound-based cleaning device was larger than its total cost weight since the benefit-cost value was greater than 1, which was 1.6 times of that of to compared product. Therefore, from the economic perspective, it is worth to develop the cleaning device for photovoltaic power generation systems applying ultrasound technology.

• ICROS
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• v.21 no.2
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• pp.25-30
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• 2015

본 논문에서는 간병인의 도움없이 자가 보행 재활에 효과적으로 사용될 수 있는 새로운 개념의 가슴 착용형 로봇을 개발하였다. 개발된 로봇의 특징은 크게 세 가지로 나뉜다. 첫째, 구조적 특징으로써, 하박에 착용하는 기존 지팡이 타입의 엘보 크러치와 달리 개발된 로봇은 가슴에 착용되어 착용자의 두 팔을 자유롭게 하는 동시에 팔의 부담을 제거하여 준다. 둘째는 구동 알고리즘의 특징으로써, 가슴부에 부착된 압력센서로부터 사용자의 보행의도를 자동적으로 인식하여 로봇의 다리를 이동시킨다. 또한 착용자의 안전을 위해 초음파 센서를 이용하여 착용자 전방에 장애물이 나타날 시 보행을 멈추고 경고음을 발생시킨다. 마지막으로, 스카치요크 메커니즘을 사용하여 지지다리의 상승과 하강 시 지면 반발력으로 인하여지지 발 상/하강 모터에 과도한 토크가 부과되지 않도록 하였다. 이러한 세 가지 특징으로부터 개발된 로봇이 자가 보행 재활에 효과적으로 사용될 수 있음을 실험적으로 보였으며, EMG (Electromyography) 센서를 이용하여 근력 보조 성능을 정량적으로 검증하였다.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.2
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• pp.155-161
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• 2012

It was attempted to evaluate the microstructure and quality of various types of cast iron by ultrasonic velocity measurement. Three types of commercial gray cast iron and ductile cast iron were used for this investigation, respectively. One type of the ductile cast iron was heat-treated as a function of annealing time to produce different microstructure. Ultrasonic velocity measurement, microstructural analysis (pearlite area fraction, graphite length and nodularity), and hardness measurement were performed to find empirical correlations among these parameters. Ultrasonic velocity of ductile cast iron was markedly faster than that of gray cast iron. Ultrasonic velocity decreased with the decrease of fraction of pearlite structure. As a quality monitoring parameter of cast iron, potential of ultrasonic velocity was suggested.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.6
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• pp.501-510
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• 2000

Recently, advanced signal analysis which is called "time-frequency analysis" has been used widely in nondestructive evaluation applications. Wavelet transform(WT) and Wigner Distribution are the most advanced techniques for processing signals with time-varying spectra. Wavelet analysis method is an attractive technique for evaluation of material characterization nondestructively. Wavelet transform is applied to the time-frequency analysis of ultrasonic echo waveform obtained by an ultrasonic pulse-echo technique. In this study, the feasibility of noise suppression of ultrasonic flaw signal and frequency-dependent ultrasonic group velocity and attenuation coefficient using wavelet analysis of ultrasonic echo waveform have been verified experimentally. The Gabor function is adopted the analyzing wavelet. The wavelet analysis shows that the variations of ultrasonic group velocity and attenuation coefficient due to the change of material characterization can be evaluated at each frequency. Furthermore, to assure the enhancement of detectability and naw sizing performance, both computer simulated results and experimental measurements using wavelet signal processing are used to demonstrate the effectiveness of the noise suppression of ultrasonic flaw signal obtained from austenitic stainless steel weld including EDM notch.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.85-86
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• 2009

A nondestructive test method based on the self-compensating frequency response function is proposed in this paper to quantitatively measure the attenuation in concrete materials. Since the proposed technique measures inherent attenuation of material itself, more stable experimental results can be expected. In advance, comparison of the experimental results to those obtained by other methods shows the repeatability and accuracy of the proposed technique.

• Journal of Institute of Control, Robotics and Systems
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• v.1 no.1
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• pp.43-49
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• 1995

본 논문에서는 초음파 센서와 시각 센서에서 얻은 전방향 센서 데이타를 이용하여 실내 이동 로봇용 국부 유도 항법을 위한 새로운 환경 모델링 방법을 제안한다. 그리고 이 두 종류의 센서 데이타에 포함된 불확실성을 주관적 지식과 퍼지 연산법을 사용하여 정량적으로 다룰 수 있는 센서 융합법을 제안한다. 이 방법을 사용하여, 로봇의 현재 위치와 목표 위치간의 기하학적 관계를 더욱 정확하게 얻을 수 있다. 실험 결과를 통하여 제안된 모델링과 센서 융합법이 실내 이동 로봇 항법에 효과적임을 보였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.490-492
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• 2016

Pancreatic ultrasound imaging is used to diagnose pancreatic hyperplasia, pancreatic steatosis, pancreatic cancer and the like. If the diagnosis of pancreatic steatosis is pancreatic parenchyma echo shades splashes spleen than in the pancreas ultrasound it determines that the fat is deposited. And research on ultrasound imaging of pancreatic cancer but is actively conducted research studies on pancreatic steatosis is insufficient In addition, pancreatic steatosis is often an error in accordance with the diagnostic criteria are vague and subjective diagnosis of the artisan. This study was a quantitative analysis using the feature value extracting a feature of an image extracted by applying a parameter to the algorithm GLCM image of the normal and pancreatic fat. Setting a region of interest ($5{\times}5pixel$) in the mild 89 case, moderate 89 case, severe 89 case, total image 267 case using GLCM algorithm, and using the Autocorrelation, Sum average, Sum of squares, Sum varience 4 kinds parameter in each image It was analyzed.