• Advances in robotics research
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• v.1 no.2
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• pp.155-169
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• 2014

Study results in the last decades show that amount and quality of physical exercises, then the active participation, and now the cognitive involvement of patient in rehabilitation training are known of crux to enhance recovery outcome of motor dysfunction patients after stroke. Rehabilitation robots mainly have been developing along this direction to satisfy requirements of recovery therapy, or focusing on one or more of the above three points. Therefore, neuro-machine interaction based active rehabilitation robot has been proposed for assisting paralyzed limb performing designed tasks, which utilizes motor related EEG, UCSDI (Ultrasound Current Source Density Imaging), EMG for rehabilitation robot control and feeds back the multi-sensory interaction information such as visual, auditory, force, haptic sensation to the patient simultaneously. This neuro-controlled and perceptual rehabilitation robot will bring great benefits to post-stroke patients. In order to develop such kind of robot, some key technologies such as noninvasive precise detection of neural signal and realistic sensation feedback need to be solved. There are still some grand challenges in solving the fundamental questions to develop and optimize such kind of neuro-machine interaction based active rehabilitation robot.

• Journal of Biomedical Engineering Research
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• v.10 no.2
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• pp.165-172
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• 1989

In this paper, the temperature dependence of tissue is estimated by measuring the attenuation coefficient and the propagation velocity of ultrasonic reflection signal. And, on the basis of expeiments, the possibility of non- invasive temperature estimation is considered. Specimens in the experiment are acryl 1)late. muscle, fat and liver of pig. The temperature of specimen is controlled by water bath which is able to adjust temperature a quarter of a degree. Through the series of experiments, we conformed that the ultrasonic parameters have lin earity to a certain extents with the change of tissue's temperature. And we expect that noninvasive temperature estimation of tissue can be realized after several preconditions be satisfied with the standard experiment conditions and a great number of base data.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.7
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• pp.711-717
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• 2007

Location information will become increasingly important for future Pervasive Computing applications. Location tracking system of a moving device can be classified into two types of architectures: an active mobile architecture and a passive mobile architecture. In the former, a mobile device actively transmits signals for estimating distances to listeners. In the latter, a mobile device listens signals from beacons passively. Although the passive architecture such as Cricket location system is inexpensive, easy to set up, and safe, it is less precise than the active one. In this paper, we present a passive location system using Cricket Mote sensors which use RF and ultrasonic signals to estimate distances. In order to improve accuracy of the passive system, the transmission speed of ultrasound was compensated according to air temperature at the moment. Upper and lower bounds of a distance estimation were set up through measuring minimum and maximum distances that ultrasonic signal can reach to. Distance estimations beyond the upper and the lower bounds were filtered off as errors in our scheme. With collecting distance estimation data at various locations and comparing each distance estimation with real distance respectively, we proposed an equation to compensate the deviation at each point. Equations for proposed algorithm were derived to calculate relative coordinates of a moving device. At indoor and outdoor tests, average location error and average location tracking period were 3.5 cm and 0.5 second, respectively, which outperformed Cricket location system of MIT.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.835-838
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• 2002

A running high voltage equipments produce ultrasonic wave that has unique sound by the specific characteristics of the electricity. The generation of the ultrasonic wave is made by the electric transform like arcing, corona, and tracking so on. The mechanical losses and fatal human damages are happened by the electric failure of high voltage equipments. To prevent and diagnose the obstacle factors of the high voltage equipments, the measurement of the ultrasonic wave became to be prominent. However standardized data have been a deficient situation by now. This paper measures the ultrasonic wave coming from the real running transformer equipments and transforms it as an audio frequency. Measured data represents as frequency and time domain through the FFT(Fast Fourier Transform) transform. In conclusion, the purpose of this paper is to standardize the analyzed data.

• Smart Structures and Systems
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• v.17 no.1
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• pp.31-43
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• 2016

Applications of ultrasonic tomography to concrete structures have been reported for many years. However, practical and effective application of this tool for nondestructive assessment of internal concrete condition is hampered by time consuming transducer coupling that limits the amount of ultrasonic data that can be collected. This research aims to deploy recent developments in air-coupled ultrasonic measurements of solids, described in Part 1 of this paper set, to concrete in order to image internal inclusions. Ultrasonic signals are collected from concrete samples using a fully air-coupled (contactless) test configuration. These air coupled data are compared to those collected using partial semi-contact and full-contact test configurations. Two samples are considered: a 150 mm diameter cylinder with an internal circular void and a prism with $300mm{\times}300mm$ square cross-section that contains internal damaged regions and embedded reinforcement. The heterogeneous nature of concrete material structure complicates the application and interpretation of ultrasonic measurements and imaging. Volumetric inclusions within the concrete specimens are identified in the constructed velocity tomograms, but wave scattering at internal interfaces of the concrete disrupts the images. This disruption reduces defect detection accuracy as compared with tomograms built up of data collected from homogeneous solid samples (PVC) that are described in Part 1 of this paper set. Semi-contact measurements provide some improvement in accuracy through higher signal-to-noise ratio while still allowing for reasonably rapid data collection.

• Journal of Biomedical Engineering Research
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• v.17 no.4
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• pp.469-478
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• 1996

In the conventional digital ultrasound scanner, the reflected signal is sampled either in polar coordinates of R-$\theta$ method, or in Cartesian coordinates of uniform ladder algorithm (ULA). The R-$\theta$ scan method necessitates a coordinate transform process which makes hardware complex in comparison with ULA scan mrthoA In spite of this complexity, R-$\theta$ method has a good resolution in ultrasonographic (US) image, since scan direction of the US imaging is a radial direction. In this paper, a new digital scan converter is proposed, which is named the radius uniform ladder algorithm (RULA). The RULA has the rome scan direction as the US scanning in the radial direction and as the display space in the $\theta$ direction. In tllis new approach, sampled points we uniformly distributed in each horizontal line i.n well as in each radial ray so that the data are displayed in the Cartesian coordinates by the 1-D interpolation process. The propped algorithm has an uniform resolution in the periphery and the center field in comparison with equi-angle ULA and equi-interval ULA. To extend the scan angle, concentric square raster sampling (CSRS) is adopted with reduction of discontinuities on the junctions between horizontal scan and vertical scan. The discontinuities are reduced by using the hmction filtering along the $\theta$ direction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1047-1056
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• 2007

Basically, an ultrasonic imaging system has two fundamental imaging modes available. One is the B-mode imaging modality which provides an image of reflection coefficient, and the other is the Doppler color flow mode that maps blood flow inside the human heart and blood vessels. This paper presents a new method of detecting and compensating for aliasing that occurs when the Doppler frequency exceeds one-half of the pulse-repetition frequency (PRF). Its validity is shown by computer simulation. The new method not only extends the measurable Doppler frequency, but also helps to reduce the effect of noise. The results show that the aliasing can be compensated for correctly fur signal-to-noise ratios down to 20 dB.

• Journal of Power System Engineering
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• v.17 no.4
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• pp.72-78
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• 2013

Compacted graphite iron 340 was carried out the heat treatment from 873 to 1,273 K. Compacted graphite iron 340 was evaluated relationship between the sound velocity, the attenuation coefficient and the tensile strength. The obtained results are as following. The signal strength of C scan images were weak according to increasing of heat treatment temperature and time. The amplitude of A scan and B scan was also low. This can be cause that the graphite was grown into the type of vermicular, and the many of grain boundary with ultrasound scattering were increase. The sound velocity was depend upon the heat treatment temperature and time, the attenuation coefficient had nothing to do with the temperature and time. The higher the heat treatment temperature, the tensile strength and the sound velocity were decreased. However, the tensile strength was proportional to the sound velocity. The higher tensile strength, the faster the sound velocity.

• Journal of Yeungnam Medical Science
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• v.39 no.3
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• pp.262-265
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• 2022

Penile Mondor disease (MD) is a palpable, painful, subcutaneous induration caused by superficial dorsal penile vein thrombosis. We report a case of penile MD that was suspected to be related to prolonged oral sildenafil use. A 46-year-old man visited our emergency department with sustained penile pain and swelling that began 7 hours after sexual intercourse. He had used oral sildenafil intermittently for 11 years and engaged in sexual intercourse the previous night after taking sildenafil. Examination revealed no evidence of intercourse-related trauma to the genital area or an increase in penile skin temperature. However, penile swelling and tenderness over the protruding dorsal penile vein were noted. A color Doppler ultrasound examination was performed immediately, which showed hyperechoic thrombosis in the right superficial dorsal penile vein that was dilated, with soft tissue swelling and no detectable flow signal in the thrombotic lesion. The patient was diagnosed as having penile MD. The patient was treated conservatively. Some reports have indicated the involvement of sildenafil in thrombogenesis. Physicians should be aware that prolonged oral sildenafil use may be associated with penile MD.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3844-3853
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• 2023

Although radiation and chemotherapy methods for cancer therapy have advanced significantly, surgical resection is still recommended for most cancers. Therefore, intraoperative imaging studies have emerged as a surgical tool for identifying tumor margins. Intraoperative imaging has been examined using conventional imaging devices, such as optical near-infrared probes, gamma probes, and ultrasound devices. However, each modality has its limitations, such as depth penetration and spatial resolution. To overcome these limitations, hybrid imaging modalities and tracer studies are being developed. In a previous study, a multi-modal laparoscope with silicon photo-multiplier (SiPM)-based gamma detection acquired a 1 s interval gamma image. However, improvements in the near-infrared fluorophore (NIRF) signal intensity and gamma image central defects are needed to further evaluate the usefulness of multi-modal systems. In this study, an attempt was made to change the NIRF image acquisition method and the SiPM-based gamma detector to improve the source detection ability and reduce the image acquisition time. The performance of the multi-modal system using a complementary metal oxide semiconductor and modified SiPM gamma detector was evaluated in a phantom test. In future studies, a multi-modal system will be further optimized for pilot preclinical studies.