• Proceedings of the KOR-BRONCHOESO Conference
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• 1982.05a
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• pp.10.1-10
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• 1982

The use of phonosurgery in the recent development of laryngomicrosurgery has enabled the restoration of a normal voice in respect to functional laryngeal surgery which in Korea in the past limited to simple removal of benign laryngeal tumor such as laryngeal polyp or nodules and cordal injection of $Teflon^{{\circledR}}$ for the treatment of recurrent nerve paralysis under the vision of suspension laryngoscopy. Performance of phonosurgery for the treatment of cord paralysis, mutational dysphonia, vocal cord atrophy, hyperkinetic dysphonia and sulcus vocalis is a happy event in the view point of development of phonosurgery in Korea. In this aspect thyroplasty to change the position and physical characteristics of the cord outside the glottis instead of the direct handling of the vocal cord through direct endoscopy is popular. Among the 4 types of thyroplasty, classified by Insshiki(1974), type I thyroplasty(1ateral compression of vocal cord) and type IV thyroplasty(lengthening of vocal cord) were effective in the treatment of unilateral vocal cord paralysis. Advantages of this operation are the fine adjustment of the degree of lateral compression under local anesthesia according to the phonation of the patient during operation and avoidance of dyspnea and intralaryngeal hemorrhage due to the manipulation outside the internal perichondrium of the thyroid cartilage. We did 7 cases of thyroplasty for the treatment of unilateral vocal cord paralysis in the 7 months from September 1981 to March 1982. Before the operation aerodynamic study, psychoacoustical evaluation, stroboscopy and sound spectrographic analysis were done. Two months after the operation the above procedures were performed again. Results of preoperative and postoperative examination were compared and the following results were obtained. 1) In the aerodynamic study, maximum phonation time increased to 158% of the preoperative value and the phonation quotient and the mean flow rate decreased to 58% and 54% of preoperative values. 2) The degree of hoarseness improved in the psychoacoustical evaluation and the glottic chink during phonation was decreased in the stroboscopic examiantion. 3) In the sound spectrographic analysis, periodicity was much restored and noise distribution decreased especially in the high frequency area.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.3 s.96
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• pp.290-296
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• 2005

This paper proposes the modeling scheme of the Miniature Universal Testing Machine (MUTM) composed of 36 thin-beam-type bimorph PZTs and the control algorithm to minimize the residual vibration of the MUTM in the dynamic testing of specimens. In the operation of the MUTM, hysteresis, residual displacement and vibration of it are major issues. From the analysis of the MUTM behaviors, the hysteresis is described by the curving fitting scheme with the function of an input voltage. The dynamic characteristics of the MUTM are identified by the frequency domain modeling technique based on the experimental data. The interested bandwidth is focused on 125-315HZ for effective modeling and control. For the robust vibration control of the MUTM, the sliding mode control and the Kalman filter as observer are proposed. The paper also proposes the best input signal type to operate the MUTM effectively. The feasibility of the proposed modeling scheme and control algorithm are tested and verified experimentally.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.476-481
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• 2004

This paper proposes the modeling scheme of the Miniature Universal Testing Machine (MUTM) composed of 36 thin-beam-type bimorph PZTs and the control algorithm to minimize the residual vibration of the MUTM in the dynamic testing of specimens. In the operation of the MUTM, hysteresis, residual displacement and vibration of it are major issues. From the analysis of the MUTM behaviors, the hysteresis is described by the curving fitting scheme with the function of an input voltage. The dynamic characteristics of the MUTM are identified by the frequency domain modeling technique base on the experimental data. The interest bandwidth is focused on 125-315HZ for effective modeling and control. For the robust vibration control of the MUTM, the sliding mode control and the Kalman filter as observer are proposed. The paper also proposes the best input signal type to operate the MUTM effectively. The feasibility of the proposed modeling scheme and control algorithm are tested and verified experimentally.

• Journal of Digital Contents Society
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• v.18 no.4
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• pp.699-706
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• 2017

This study aims to investigate the effects of a massage device with vibration and pressure functions and a manual massage on the degree and duration of pain among patients after intramuscular injection. This study used a quasi-experimental design with nonequivalent control group. The experimental group had lower pain scores (t= 7.40, p =.001) and shorter durations of pain (t= 5.25, p=.001) than the control group. The results showed that after intramuscular injection, a massage device with vibration and pressure functions effective to reduce the degree and duration of pain than a manual massage. Therefore, the application of a massage device with vibration and pressure functions after intramuscular injection will contribute to the promotion of patient safety and the reduction of nurse workload.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1982.05a
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• pp.11.2-12
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• 1982

The major advancement in phonosurgery due to recent development of laryngomicrosurgery enabled more accurate diagnosis and treatment of patient with voice disorders. Among large proportion of voice disordered patients, prominent linear furrow running parallel along the free edge of vocal cord extending from the vocal process to anterior commissure can be seen as well as incomplete closure during phonation. These cases were illustrated and coined as sulcus vocalis by Salvi in 1901, since then other similar paper was reported in Europe and Japan, but has not been reported in Korea. The exact etiology and therapeutic methods of sulcus vocalis has not been elaborated. At Department of Otolaryngology of Yonsei University College of Medicine a series of voice analysis were performed among those 35 patients with sulcus vocalis visited to Vocal Dynamics Laboratory from May, 1981 to March, 1982. Following is the result of clinical statistical investgation and therapeutic modality. 1) The incidance of sulcus vocalis among 290 patients with voice disorder visited to Vocal Dynamics Laboratory was approximately 12%(35 cases). 2) Onset of this voice disorder was most frequent among patient under 10 year-old groups; 19 cases (54%) followed by second decade, third decade groups in decreasing frequency respectably. 3) The etiology of sulcus vocalis was mostly unknown. The sequelae after measle (4 cases) and severe upper respiratory infection (3 cases) and congenital deformity (2 cases) were the possible causes of sulcus vocalis. 4) These patients were involved bilaterally in 25 cases (71%), left side only in 8 cases (23%) and right side only in 2 cases (6%). 5) Almost all patients complained hoarseness and 7 patients were suffering from chronic laryngitis. 6) In aerodynamic analysis, Maximal Phonation Time was decreased in 20 cases (57%), Phonation Quotient was increased in 22 cases (63%) and Mean Air Flow Rate was increased in 23 cases (66%). 7) Among them, 33 cases were analyzed with stroboscopy. The findings were as follows; incomplete glottic closure during phonation in 31 cases (93%), regular vocal cord movement in whole cases, asymmetric cord movement in 4 cases (12%), decreased amplitude in 5 cases (21%) and small mucosal wave in 24 cases (73%). 8) Intracordal Teflon injection in 5 cases and Sulcusectomy in 1 cases were performed as therapeutic management, however, the therapeutic results were not effective except one case with Teflon injection.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.14 no.1
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• pp.16-25
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• 2003

Background and Objectives : Electroglottography(EGG) is a non-invasive method of monitoring the vocal cord vibration by measuring the variation of physiological impedance across the vocal folds through the neck skin. It reveals especially the vocal fold contact area and is widely used for basic laryngeal researches, voice analysis and synthesis. The purpose of this study is to investigate the effectiveness of EGG parameters in differential diagnosis of laryngeal cancer. Materials and Methods : The author investigated 10 laryngeal cancer and 25 benign laryngeal disease patients who visited at the Department of Otolaryngology, Pusan National University Hospital. The EGG equipment was devised in the author's Department. Among various parameters of EGG, closed quotient(CQ), speed quotient(SQ), speed index(SI), Jitter, Shimmer, Fo were determined by an analysis program made with MATLAB 6.5$^{\circledR}$(Mathwork, Inc.). In order to differentiate various laryngeal diseases from pathologic voice signals, the author has used the electroglottographic parameters using the neural network of multilayer perceptron structure. Results : SQ, SI, Jitter and Shimmer values except those of CQ and Fo showed remarkable differences between benign and malignant laryngeal disease groups. From the artificial neural network, the percentage of differentiating the laryngeal cancer was over 80% in SQ, SI, Jitter, Shimmer except for CQ and Fo. These results indicated that it is possible to discriminate the benign and malignant laryngeal diseases by EGG parameters using the artificial neural network. Conclusion : If parameters of EGG which can reveal for the pathology of laryngeal diseases are additionally developed and the current classification algorithm is improved, the discrimination of laryngeal cancer will become much more accurate.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.2
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• pp.128-135
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• 2004

Generally, heavy electronic products undergo many different types of shocks in transportation from a manufacturer to customers. Cushioning package is used to protect electronic products from severe shock environments. Since the mass distribution of heavy electronic products is usually unbalanced and complex. it is very difficult to design a cushioning package with having high performance by considering only the equivalent stiffness of that. Therefore, when designing the cushioning package for a heavy electronic product, it is necessary to optimize its shape in order to maximize the cushioning performance. In this study, it is focused on designing an optimal shape of cushioning package for a large refrigerator and an efficient design method is suggested by using a dynamic finite element analysis. As the results of this study the optimal shape of cushioning package, which has high cushioning performance and minimized volume, was obtained through the mechanical drop analysis and a optimization process. Through free drop tests of refrigerators, it was identified that the cushioning performance of the cushioning package was improved up by 25% and the its own volume was reduced by 22 ％.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.1
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• pp.37-42
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• 2005

The localization of manufacturing technique development is actualizing for low cost with supplies of display devices. We need more high cutting technique because consumers want flat glasses of various sizes. Recently, most general two methods are normal wheel cutting and laser cutting, but both of them have some faults. First, the wheel cutting has cracks and sharp edges of sections. Second, it is easy for laser cutting to cut curved lines. however, it has thermal damage and low traverse speed. I suggest a new cutting method by high-wave frequency vibration wheel cutting(HFVC), which is good for quality improvement. Vertical cracks and crack depth is observed, after HFVC. When the average of the crack depth is $30{\mu}m$ and the average of the wallner liner depth is $200{\mu}m$, it has the most high quality of the sections in this experiment. As a result, when we consider between the normal wheel cutting method and the HFVC method, the latter has low cracks and good quality.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.677-683
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• 2003

Generally, heavy electronic products undergo many different types of shocks in transporting from a manufacturer to customers. Cushioning package materials are used to protect electronic products from severe shock environments. Since the mass distributions of heavy electronic products are usually unbalanced and complex, it is very difficult to design a cushioning package with haying high performance by considering only the equivalent stiffness of that. Therefore, when designing the cushioning material for a heavy electronic product, it is necessary to optimize its shape in order to maximize the cushioning performance. In this study, it is focused on designing an optimal shape of cushioning material for a large-sized refrigerator and an efficient design method is suggested by using a dynamic finite element analysis. As the results of this study, the optimal shape of cushioning material, which has high cushioning performance and minimized volume, was obtained from the drop analysis and a optimization process. From free drop tests of a refrigerator, it was identified that the cushioning performance of the optimal package were improved up to 16 % and the volume of it was reduced in a range of 22 %.

• Tribology and Lubricants
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• v.35 no.1
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• pp.71-76
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• 2019

The differential planetary gear reducer as a main component of the concrete mixer driving mechanism requires a strong torque to mix concrete compounds. As this component is currently dependent on imports, it is necessary to develop it by conducting a study on vibration analysis and the resonance problem. The noise and vibration of a concrete mixer reducer increase owing to the transmission error of planetary gears, and the damage of components occurs owing to the problems in design and production. In this study, the tooth-passing frequency is calculated to evaluate the noise and vibration of a mixer reducer, and a fast Fourier transform (FFT) analysis is conducted through a vibration test using an acceleration sensor. The vibration of the reducer is measured at three points of input and output of the shaft and planetary gear housing with fixed and variable revolutions per minute. The operating conditions of gears and bearings are evaluated by performing the FFT analysis, and the resonance problem is verified. The results show that No. 1 pinion and ring gears revolve disproportionately. The amplitude values appear high, and the wear of tooth faces occur in tooth-passing frequencies and harmonic components of No. 1 and No. 2 pinion-ring gears. Therefore, we conclude that design changes in the reducer and a correction of tooth profiles are required.