• Journal of Broadcast Engineering
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• v.11 no.4 s.33
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• pp.448-457
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• 2006

HRTF DB, including the information of the sounds which is arrived to our ears, is generally used to make a 3D sound. But it can decline some three-dimensional effects by the confusion between front and back directions due to the non-individual HRTF depending on each listener. In this paper, we propose a new method to use psychoacoustic theory that reduces the confusion of sound image localization. And we make use of an excitation energy by the sense of hearing. This method is brought HRTF spectrum characteristics into relief to draw out the energy ratio about the bark band. Informal listening tests show that the proposed method improves the front-back sound localization characteristics much better than the conventional methods.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.2
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• pp.116-123
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• 2002

Applying a general coupled lateral and torsional vibration finite element model of gear pair element, this paper intends to look into in detail the coupled lateral and torsional vibration characteristics of a turbo-chiller rotor bearing system, having a bull-pinion speed increasing gear. Investigations have been carried out systematically by comparing the uncoupled and coupled natural frequencies and their mode shapes upon varying the gear mesh stiffness with considerations on rotating speeds, and also by comparing the strain energies of lateral and torsional vibration modes. Results hale shown that some modes may hale the coupled lateral and torsional mode characteristics as the gear mesh stiffness Increases over a certain value, and moreover that their associated dominant modes may be different from their initial modes, j.e., a certain dominant mode may change from an initial torsional one to a lateral one or from an initial lateral one to a torsional one.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.36 no.4
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• pp.1-18
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• 2023

Objectives : This study retrospectively analyzed the medical records of patients admitted to Korean medicine ophthalmology, otolaryngology and dermatology department of Daejeon Korean medicine hospital from March 2018 to February 2023 to analyze the characteristics of patients receiving inpatient treatment. Methods : We retrospectively analyzed inpatients who admitted to ophthalmology & otolaryngology & dermatology clinic of Daejeon Korean medicine hospital from March 1st, 2018 to February 28th, 2023, according to gender, age, year, season, detailed subdivision. The statistical analysis performed using IBM SPSS 29.0 for Windows. Results : 1. Examining the gender distribution of the patient group, there were 367 female patients, accounting for 71.7% of the total patients, and 145 male patients, accounting for 28.3% of the total patients. 2. When analyzing inpatients by subdivision, otology accounted for more than half of the total number of inpatients, and the combined number of otology and dermatology accounted for more than 80% of the total. 3. As a result of analyzing inpatients by frequent disease, Sudden hearing loss was a significantly higher number of patients, accounting for 22.7% of all inpatients. Conclusions : It was found that the proportion of patients with otologic diseases was very prominent. It is thought that further research is needed to see if the trend of increasing demand for otologic diseases continues.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.20 no.1
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• pp.57-62
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• 2009

Background and Objectives : There are few studies reported that specifically examine the laryngeal function in patients with profound hearing loss or deafness, This study was designed to examine videostroboscopic findings and phonetic characteristics in adult patients with prelingually deaf. Materials and Method: Sixteen patients (seven males, nine females) diagnosed as prelingually deaf aged from 19 to 54 years, and were compared with a 20 normal control group with no laryngeal pathology and normal hearing group, Videostroboscopic evaluations were rated by experienced judges on various parameters describing the structure and function of the laryngeal mechanism during comfortable pitch and loudness phonations. Acoustic analysis test were done, and a nasalance test performed to measure rabbit, baby, and mother passage. CSL were measured to determine the first and two formant frequencies of vowels /a/, /i/, /u/, Statistical analysis was done using Mann-Whitney U or Wilcoxon signed ranks test. Results: Videostroboscopic findings showed phase symmetry but significantly more occurrences decrement in the amplitude of vibration, mucosal wave, irregularity of the vibration and increased glottal gap size during the closed phase of phonation, In addition, group of prelingually deaf patients were observed to have significantly more occurrences of abnormal supraglottic activities during phonation. The percentage of shimmer in the group of prelingually deaf patients were higher than in the control group. Characteristics of vowels were lower of the second formant of the vowel /i/. Nasalance in prelingually deaf patients showed normal nasality for all passages, Conclusion: Prelingually deaf patients show stroboscopic abnormal findings without any mucosal lesion, suggesting that they have considerable functional voice disorder. We suggest that prelingually deaf adults should perform vocal training for normalized laryngeal function after cochlear implantation.

• Journal of Preventive Medicine and Public Health
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• v.10 no.1
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• pp.94-101
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• 1977

Noise pollution, both in the environment and in the workplace, has been recognized as a major health hazard -one that can impair not only a person's hearing but also his physical and mental well-being. As industrialization progresses, the prevalence rate of occupational diseases is increasing, especially hearing loss, which has the highest prevalence rate among the occupational diseases. The major cause of noise is the construction of various large industries without any regulation of noise sources. Therefor, we must establish an enactment to control mechanical noise sources. as soon as possible. For the purpose of controlling the noise source, we must have exact data about such things as the sound level, the frequency of the peak sound and the revolutions per minute (r.p.m.) of the machine (a measure of the power of its motor). This study was undertaken in order to define the noise characteristics, the power of the machine's motor, the change of the sound level and the peak sound as the r.p.m. increases, and the permissible exposure time. The sample size of this study was 74 machines at 11 plants in 6 industries. The results are as follows; 1. The breakdown of the types of mechanical noise noted was : 63.6% continuous normal sound, 26.9% intermittent sound, 4.7% continuous repeating sound and 4.6% impulsive sound. 2. With respect to the type of industry, the overall sound level was the highest in the mechanical industry, with $103.8{\pm}2.8dB(A)$, and lowest in the textile industry, with $89.2{\pm}1.43dB(A)$. 3. With respect to the type of machine, the highest sound level was 124 dB(A) caused by Gauzing(II), in the mechanical industry, and the lowest was 76 dB(A) caused by Attachment (Jup Chack) (I) in the timber industry. 4. The shortest permissible exposure time to Gauzing(II) in the mechanical industry was less than 15 minutes. 5. Among 74 machines, 68.2% of the peak sound was situated in the high frequency range (52.7% at 2 KHz, 4.1% at 4 KHz and 1.4% at 8 KHz). 41.8% of the peak sound was in the middle frequency range (4.1% at 250Hz, 14.8% at 500Hz and 22.9% at 1KHz). 6. If one machine had two motors or more, the peak sound was shifted to the low frequency range. 7. As the r.p.m. increased, the overall and peak sound levels were increased without any change of the frequency of the peak sound. 8. Whenever the machines had the same kind and the same r.p.m., the overall and peak sounds were changed by the physicochemical characteristics of the raw materials and the management.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.5 s.311
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• pp.79-87
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• 2006

In this study, we evaluated the performance of a companding strategy as a preprocessing for speech enhancement and noise reduction. The proposed algorithm is based on two tone suppression that is human's hearing characteristics. This algorithm enhances spectral peak of speech signal and reduces background noise, however it has tradeoff characteristics between speech distortion and noise reduction due to limited channel number and nonlinear block. Therefore, we designed two different companding structures that have relative characteristics of noise reduction and speech distortion and found suitable companding structures by difference of individual speech perception ability in noise environment. Thus we proposed speech perception enhancement of cochlear implant user in noise environment with low SNR. The performance of the proposed algorithm was evaluated through 5 normal hearing listeners using noise band simulation. Improvement of speech perception was observed for all subjects and each subject preferred the different type of companding structure.

• Journal of Internet Computing and Services
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• v.18 no.1
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• pp.57-64
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• 2017

Recent automobile manufacturing technology has improved not only the function and performance of cars, but also the audio systems in cars so as to increase their marketability. Automobile manufacturers always have the option of simply installing an expensive acoustic system to help customers enjoy a high-level sound quality car audio system. However, this also tends to increase the MSRP (Manufacturer's Suggested Retail Price) of the car. Therefore, it is desirable, where possible, to enhance the sound quality of plainer, less expensive audio devices to help customers feel as if they have a high-quality and expensive audio device in their car. In order to make this happen, the manufacturer must develop an optimal interior environment and audio system at a relatively lower cost. To this end, features of the car audio system can be enhanced by analyzing audio frequency response and using performance metrics to figure out the characteristics of the human auditory system. This study analyzed the sound field of Korean Recreation Vehicles (RVs) using the Internet of Things (IoT) sensor for the measurement of car audio system. As a result, high energy of sensitive bandwidth, one of the human auditory characteristics often makes annoying sound. This study also found that increasing the frequency response flatness is required by taking human auditory field into account when designing the car audio system for the future.

• Proceedings of the KSPS conference
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• 2007.05a
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• pp.302-304
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• 2007

The purpose of this study was to evaluate speech production ability of congenitally deaf children with cochlear implant. Forty children were participated in the study. The results are following: (1) mean of speech intelligibility score was 3.05 in 5 point scale, (2) mean of percent of correct vowels was 86.19%, and mean of percent of correct consonants was 74.89%, and (3) voice profiles showed their voice were high pitched, hypernasal, and breathy. But 12.5% of the children were evaluated as having normal voice quality. Overall speech production abilities of children with cochlear implant were superior than the deaf children's result reported in literatures. Meanwhile their abilities were not same as children with normal hearing.

• Journal of Genetic Medicine
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• v.18 no.2
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• pp.83-93
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• 2021

Charcot-Marie-Tooth disease (CMT) is the most common hereditary motor and sensory peripheral neuropathy. CMT is usually classified into two categories based on pathology: demyelinating CMT type 1 (CMT1) and axonal CMT type 2 (CMT2) neuropathy. CMT1 can be distinguished by assessing the median motor nerve conduction velocity as greater than 38 m/s. The main clinical features of axonal CMT2 neuropathy are distal muscle weakness and loss of sensory and areflexia. In addition, they showed unusual clinical features, including delayed development, hearing loss, pyramidal signs, vocal cord paralysis, optic atrophy, and abnormal pupillary reactions. Recently, customized treatments for genetic diseases have been developed, and pregnancy diagnosis can enable the birth of a normal child when the causative gene mutation is found in CMT2. Therefore, accurate diagnosis based on genotype/phenotypic correlations is becoming more important. In this review, we describe the latest findings on the phenotypic characteristics of axonal CMT2 neuropathy. We hope that this review will be useful for clinicians in regard to the diagnosis and treatment of CMT.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.56 no.12
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• pp.749-753
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• 2013

Basically stem cells have characteristics of multi-potency, differentiation into multiple tissue types, and self-renew through proliferation. Recent advances in stem cell biology can make identifying the stem-cell like cells in various mammalian tissues. Stem cells in various tissues can restore damaged tissue. Stem cells from the adult nervous system proliferate to form clonal floating colonies called spheres in vitro, and recent studies have demonstrated sphere formation by cells in the tympanic membrane, vestibular system, spiral ganglion, and partly in the organ of Corti. The presence of stem cells in the ear raises the possibilities for the regeneration of the tympanic membrane & inner ear hair cells & neurons. But the gradual loss of stem cells postnatally in the organ of Corti may correlate with the loss of regenerative capacity and limited hearing restoration. Future strategies using endogenous stem cells in the ear can be the another treatment modality for the patients with intractable inner ear diseases.