• Investigative Magnetic Resonance Imaging
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• v.18 no.1
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• pp.70-74
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• 2014

Actinomycosis is caused by filamentous Gram positive anaerobic bacteria from the Actinomycetaceae family, and known as a rare cause of the infection at the eyeball. We report magnetic resonance findings of a 60-year-old Korean man with cervicofacial actinomycosis, including cellulitis in the eye and central nervous system actinomycosis. On orbital magnetic resonance imaging, gadolinium-enhanced T1-weight images showed multiple abnormal enhancing lesions in head and neck including right eye, and some include low signal intensities which considered as abscesses. The lesions was diagnosed as actinomycosis by incisional biopsy, and since then was cured by using antibiotics of penicillin family.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.4
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• pp.338-344
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• 2010

A double rotation C-scanning system and a software program Under-Sodium MultiVIEW have been developed for the under-sodium viewing of a reactor core and in-vessel structures of a sodium-cooled fast reactor KALIMER-600. Double rotation C-scanning system has been designed and manufactured by the reproduction of double rotation plug of a reactor head in KALIMER-600. Hardware system which consists of a double rotating scanner, ultrasonic waveguide sensors, a high power ultrasonic pulser-receiver, a scanner driving module and a multi channel A/D board have been constructed. The functions of scanner control, image mapping and signal processing of Under-Sodium MultiVIEW program have been implemented by using a LabVIEW graphical programming language. The performance of Under-Sodium MultiVIEW program was verified by a double rotation C-scanning test in water.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.3
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• pp.237-240
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• 2011

Epidermoid cysts presents as a nodular and fluctuant subcutaneous lesion beneath the skin and are most common in acne-prone areas of the head, neck and back. This cyst often arises after localized inflammation of the hair follicle and occasionally after the implantation of epithelium following trauma and surgery including a biopsy procedure. It is often associated with Gardner syndrome, particularly before puberty. The lesion is normally treated by a surgical excision or enucleation, and recurrence is uncommon. A 27 year old woman complained of a swelling of the left parotid gland when she visited our clinic. A cystic lesion was found in the left parotid gland from the high signal intensity on the MR images. Ultrasonography showed that the cystic lesion was heterogeneous echogenic. Six months earlier, botulinum toxin was injected in her left masseter muscles six months earlier and progressive swelling of the left parotid area was noticed four months after treatment. The lesion was surgically removed. It was encapsulated by a thin wall and filled mainly with keratin. The final diagnosis was an epidermoid cyst.

• Journal of Biomedical Engineering Research
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• v.34 no.1
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• pp.24-33
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• 2013

To enhance the speech perception of hearing aid users in noisy environment, most hearing aid devices adopt various beamforming algorithms such as the first-order differential microphone (DM1) and the two-stage directional microphone (DM2) algorithms that maintain sounds from the direction of the interlocutor and reduce the ambient sounds from the other directions. However, these conventional algorithms represent poor directionality ability in low frequency area. Therefore, to enhance the speech perception of hearing aid uses in low frequency range, our group had suggested a fractional delay subtraction and integration (FDSI) algorithm and estimated its theoretical performance using computer simulation in previous article. In this study, we performed a KEMAR test in non-reverberant room that compares the performance of DM1, DM2, broadband beamforming (BBF), and proposed FDSI algorithms using several objective indices such as a signal-to-noise ratio (SNR) improvement, a segmental SNR (seg-SNR) improvement, a perceptual evaluation of speech quality (PESQ), and an Itakura-Saito measure (IS). Experimental results showed that the performance of the FDSI algorithm was -3.26-7.16 dB in SNR improvement, -1.94-5.41 dB in segSNR improvement, 1.49-2.79 in PESQ, and 0.79-3.59 in IS, which demonstrated that the FDSI algorithm showed the highest improvement of SNR and segSNR, and the lowest IS. We believe that the proposed FDSI algorithm has a potential as a beamformer for digital hearing aid devices.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.3
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• pp.369-375
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• 1997

Studies were conducted to determine the efficiency of decondensation protocols. Sperm obtained from seven normal donors was immediately washed after liquefaction and then decondensed using the method of West et al. (1989) and my original protocol. My optimized protocol entailed mixing 1 ml aliquots of semen with 4 ml phosphate buffered saline (PBS). Following centrifugation, pellets were resuspended in 1 ml PBS containing 6 mM EDTA. After centrifugation, pellets were resuspended in 1 ml PBS containing 2 mM dithiothreitol at $37^{\circ}C$ for 45 min. Following mixing with 2 ml PBS and centrifugation, pellets were resuspended by vortexing. While vortexing, 5 ml of fixative were gently added. Slide preparation was accomplished using the smear method and it was stored at $4^{\circ}C$. When comparing these protocols, the degree of sperm decondensation and head swelling was monitored by measuring nuclear length, area, perimeter, and degree of roundness using FISH analysis software. Apparent copy number for chromosome 1 and, separately, for the sex chromosomes was determined by FISH using satellite DNA probes for loci DIZ1, DXZ1 and DYZ3. Sperm treated by my decondensation protocol showed significant increases (p<0.05) in length, area, perimeter, and degree of roundness. There was a significant decrease (p<0.05) in the frequency of nuclei displaying no signal but no change in the frequency of nuclei with two signals in samples decondensed by my protocol. My data suggested that decondensation using my original protocol may lower the frequency of cells with spurious "nullisomy" due to hybridization failure without inducing spurious "disomy" resulting from increased distances between split signals.

• The Journal of Information Technology
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• v.9 no.1
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• pp.21-32
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• 2006

Acrophobia is a symptom of feeling an abnormal fear of heights. Medications or cognitive-behavior methods have been mainly used to treat the acrophobia. In these days the virtua1 reality technology has been applied to treat such an anxiety disorders. In this thesis, an telemedicine assistant system for treatment of acrophobia using biomedical signals and virtual reality technique is proposed. I made two virtual reality simulations for treatment of acrophobia and telemedicine system for communication between doctor and patient using personal computer. A virtual environment provides patient with stimuli which arouses phobia, and exposition to such environment makes him have ability to overcome the fear. Recently, the patient can take diagnosis from a medical doctor in distance with the telemedicine system. Multimedia conference service, on-line questionary, signal transfer system are needed to configure such system. Virtual reality simulation system that composed of position sensor, head mount display, and audio system, is also included in this telemedicine system. I added virtual environment update system to this virtual reality telemedicine system for treatment of acrophobia. Former acrophobia treatment systems use only patient's score of the questionary to appraise. The new system developed in this thesis uses not only patient's score of the questionary but also biomedical signals such as HR, GSR amplitude, GSR RT to increase the objectivity and quantitativity. The experimental results show that HR and GSR amplitude are useful for decision of acrophobia. We will apply this system to the acrophobia patient in distance and be able to offer better medical treatment for mental illness in near future.

• Journal of the Korean Physical Society
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• v.73 no.9
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• pp.1393-1398
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• 2018

In conventional single-photon emission computed tomography (SPECT), only the photoelectric events in the detectors are used for image reconstruction. However, if the $^{131}I$ isotope, which emits high-energy radiations (364, 637, and 723 keV), is used in nuclear medicine, both photoelectric and Compton scattering events can be used for image reconstruction. The purpose of our work is to perform simulations for Compton SPECT by using the Geant4 application for tomographic emission (GATE). The performance of Compton SPECT is evaluated and compared with that of conventional SPECT. The Compton SPECT unit has an area of $12cm{\times}12cm$ with four gantry heads. Each head is composed of a 2-cm tungsten collimator and a $40{\times}40$ array of CdZnTe (CZT) crystals with a $3{\times}3mm^2$ area and a 6-mm thickness. Compton SPECT can use not only the photoelectric effect but also the Compton scattering effect for image reconstruction. The correct sequential order of the interactions used for image reconstruction is determined using the angular resolution measurement (ARM) method and the energies deposited in each detector. In all the results of simulations using spherical volume sources of various diameters, the reconstructed images of Compton SPECT show higher signal-to-noise ratios (SNRs) without degradation of the image resolution when compared to those of conventional SPECT because the effective count for image reconstruction is higher. For a Derenzo-like phantom, the reconstructed images for different modalities are compared by visual inspection and by using their projected histograms in the X-direction of the reconstructed images.

• Journal of Audiology & Otology
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• v.24 no.4
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• pp.180-190
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• 2020

Background and Objectives: Although many studies have evaluated the effect of the digital noise reduction (DNR) algorithm of hearing aids (HAs) on speech recognition, there are few studies on the effect of DNR on music perception. Therefore, we aimed to evaluate the effect of DNR on music, in addition to speech perception, using objective and subjective measurements. Subjects and Methods: Sixteen HA users participated in this study (58.00±10.44 years; 3 males and 13 females). The objective assessment of speech and music perception was based on the Korean version of the Clinical Assessment of Music Perception test and word and sentence recognition scores. Meanwhile, for the subjective assessment, the quality rating of speech and music as well as self-reported HA benefits were evaluated. Results: There was no improvement conferred with DNR of HAs on the objective assessment tests of speech and music perception. The pitch discrimination at 262 Hz in the DNR-off condition was better than that in the unaided condition (p=0.024); however, the unaided condition and the DNR-on conditions did not differ. In the Korean music background questionnaire, responses regarding ease of communication were better in the DNR-on condition than in the DNR-off condition (p=0.029). Conclusions: Speech and music perception or sound quality did not improve with the activation of DNR. However, DNR positively influenced the listener's subjective listening comfort. The DNR-off condition in HAs may be beneficial for pitch discrimination at some frequencies.

• Korean Journal of Audiology
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• v.24 no.4
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• pp.180-190
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• 2020

Background and Objectives: Although many studies have evaluated the effect of the digital noise reduction (DNR) algorithm of hearing aids (HAs) on speech recognition, there are few studies on the effect of DNR on music perception. Therefore, we aimed to evaluate the effect of DNR on music, in addition to speech perception, using objective and subjective measurements. Subjects and Methods: Sixteen HA users participated in this study (58.00±10.44 years; 3 males and 13 females). The objective assessment of speech and music perception was based on the Korean version of the Clinical Assessment of Music Perception test and word and sentence recognition scores. Meanwhile, for the subjective assessment, the quality rating of speech and music as well as self-reported HA benefits were evaluated. Results: There was no improvement conferred with DNR of HAs on the objective assessment tests of speech and music perception. The pitch discrimination at 262 Hz in the DNR-off condition was better than that in the unaided condition (p=0.024); however, the unaided condition and the DNR-on conditions did not differ. In the Korean music background questionnaire, responses regarding ease of communication were better in the DNR-on condition than in the DNR-off condition (p=0.029). Conclusions: Speech and music perception or sound quality did not improve with the activation of DNR. However, DNR positively influenced the listener's subjective listening comfort. The DNR-off condition in HAs may be beneficial for pitch discrimination at some frequencies.

• Journal of the Korean Geotechnical Society
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• v.22 no.12
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• pp.33-43
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• 2006

Driving tests using model plastic piles with different hammer cushion materials were performed in order to evaluate the efficiency of energy transfer ratio from the hammer, degree of vibration of the surrounding ground and noise due to impacting. A small pile driving analyzer (PDA) was composed using straingages and Hopkinson bar which is measuring force signal and pile-head velocity. The hammer cushion (cap block) materials used for the model driving tests were commercial Micarta, plywood, polyurethane, rubber (SBR) and silicone rubber. The highest energy transfer ratio was obtained from Micarta in the same soil and driving conditions. Micarta was followed by polyurethane, plywood, rubber and silicone in descending order. The more efficient energy transfdr ratio of the hammer cushion materials became, the bigger average noisy (sound) level was found. In addition, Micarta and polyurethane provided bigger bearing capacities than other materials compared in the same soil and driving conditions in which the static loading tests were performed at the end of driving.