• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2A
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• pp.187-194
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• 2004

We propose priority-based reservation code multiple access (P-RCMA) which can enhance voice traffic quality of the previous RCMA. The proposed protocol maintains two power levels and consider traffic characteristics in contending shared available codes to transmit packets. P-RCMA gives priority to the voice request packets rather than data packets by capture effect at the receiver part of base station. We show numerical results from EPA (equilibrium point analysis) analysis and simulation study in terms of voice packet dropping probability and average data packet transmission delay.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.19 no.2
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• pp.85-88
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• 2008

Several parameters are used for the assessment of phonatory function and voice quality in clinical settings. Glottic airflow, subglottal pressure, mean phonation time, laryngeal resistance and voice efficiency are the most commonly used aerodynamic parameters. Aerodynamic analysis is developed to evaluate phonatory energy source and to estimate laryngeal efficiency. Also these measurements have shown the good correlation with perceptions of breathiness and findings of glottic competence. Aerodynamic study is important to understand relationships between pulmonary and phonatory function.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.6 no.1
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• pp.22-26
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• 1995

Change of voice, espicially hoarseness show irregular vibration of vocal cord. So, computerized acoustic analysis has presented many acoustic parameters for objective evaluation of voice. We objectively investigated the vocal vibration of normal persons and hoarseness patients in Korea. The RAP(relative average perturbation), PPQ(pitch period perturbation quotient) and APQ(amplitude perturbation quotient) of normal persons were compared with that of hoarseness patients with multidimensional voice program for the possibility of distinguishing the pathologic vocal vibration from normal. Authors agree that RAP, PPQ and APQ showed interesting differences between the normal and the hoarseness patients by the multivariate statistical analysis. In conculusion, relative average perturbation, pitch period perturbation and amplitude perturbation quotient might be meangingful screening parameters distinguishing hoarseness patients from normal.

• Korean Journal of Head & Neck Oncology
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• v.33 no.2
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• pp.17-22
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• 2017

Background and Objectives: Voice change after thyroidectomy may develop without injury of recurrent laryngeal nerve. Psychogenic or emotional factors related to voice change after thyroidectomy has been rarely studied. In this study, we sought to analyze the impact of anxiety on early state of post-thyroidectomy voice change. Materials and Methods: We made a retrospective chart review of 36 patients who underwent thyroidectomy for papillary thyroid carcinoma and voice exam before surgery, 2 weeks after and 1 month after surgery. All patients included in the study answered a questionnaire for State-Trait Anxiety Inventory ; STAI-KYZ (form Korean YZ). Clinico-pathologic factors and parameters of voice analysis were reviewed to analyze correlation to the anxiety index. Results: No differences were identified between clinicopathologic factors and preoperative parameters of voice analysis between patients with higher and lower level of anxiety. Noise to harmonic ratio (NHR) was higher in those patients with higher level of anxiety, 2 weeks after surgery (p=0.043). However, none of the parameters showed any difference 1 month later. Conclusion: With limited number of patients and short period of follow up, significant impact of preoperative anxiety on postoperative voice change after thyroidectomy could not be identified in this preliminary study.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.15 no.1
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• pp.5-9
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• 2004

Some patients who have undergone adenotonsillectomy (AT) or tonsillectomy(T) complain of voice change. Research was designed to determine the relationship between subjective voice change and change of parameters in boice analysis and to find the degree of voice change according to age and excised tissue volume. In 34 patients who underwent AT and 17 patients who underwent T, we measured the masalance, the fundamental frequency of /a/phonation and the formants and bandwidths of /a/, /i/, /u/ phonations. These parameters were measured preoperatively and also 7 days after the operation. Excised tissue volume was measured on operation. Postoperative changes were statistically analyzed. Any subjective voice change was asked to be reported at the visit 7 days after the operation. There was analysis for the difference of above parameters between some who answered "voice change" (A group) and the others who answered "no voice change" (B group). 24 patients(71%) who underwent AT and 4 voice change. Nasals nasalance change is an important factor in subjective voice change after AT.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.1
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• pp.48-52
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• 2005

In this paper, the spectral shape invariant real-time voice change method is proposed to change one's voice to mechanical voice. For this purpose, LPC analysis and synthesis is used to maintain the spectraum of voice and the pitch of synthesis speech can be changed freely. In the proposed method, gain matching method is applied to excitation signal generator to make the changed voice natural to hear. In order to evaluate the performance of the proposed method, voice change experiments were conducted. Experimental results showed that original speech signal is changed to the mechanical voice signal in which context of the speaker's voice is conveyed correctly in spite of drastic change of pitch. The system is implemented using TI TMS320C6711DSK board to verify the system runs in real time.

• Korean Journal of Bronchoesophagology
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• v.7 no.2
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• pp.161-167
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• 2001

Background and Objectives： Total laryngectomy is often required for advanced cases. But this operation induced the many inconvenience of basic daily life. Early diagnosis of laryngeal cancer is very important to prevent from this disastrous condition. In this point of view, mass screening test for early detection of laryngeal cancer is necessary. Screening test using voice has many advantages such as simple, less interventional. Voice collection by Automatic Response System(ARS) is comfortable and easy to got acoustic sample. Thus author tried to got the acoustic parameters which can differentiate normal, benign. and malignant laryngeal diseases and also checked the availability of parameters on neural network system. Materials and Methods: Author has evaluated the voice from 17 laryngeal cancer patients and 45 benign laryngeal disease patients who visited at Department of Otolaryngology, Pusan National University Hospital from May 1998 to April 2001, and 15 normal control. Author chose the sir Parameters (Jitt. vFo, Shim, vAm, NHR, SPI) that was thought to be related with voice collected by ARS among thirty-three parameters analysed by a Multi-Dimensional Voice Program (MDVP). Two-step neural network was used for the availability of six parameters. Results: The detection rate of normal voice by ARS voice analysis is 78.5% and detection rate of abnormal voice was 97.1 o/o. Among abnormal voice, the detection rate of benign laryngeal diseases and laryngeal cancers were 82.4 o/o, 70.6% respectively. Conclusion: Author concluded that six parameters and Matlab based neural network software may be effective in development of acoustic screening system for laryngeal cancer and further study should be necessary for development of new acoustic parameters.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.9 no.1
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• pp.47-52
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• 1998

Objectives : To compare the objective differences in voice quality and voice problems between clergies and normal male control group. Materials and Methods : The sustained vowel sound of 46 clergies and 40 normal persons were analyzed, using a videostroboscopy and acoustic analyzer. Together with these analyses, a questionnaire associated with current and past voice problems was handed over to the patients. Results : The most common symptom in subjective group was the voice fatigue. Stroboscopic findings in subjective group were as following 23 cases(50%) of pachydermia, 17 cases(37%) of phase difference, 12 cases(25%) of anterior-posterior contracture, 6 cases(13%) of vocal polyp and 3 cases(7%) of vocal nodule. The mean maximal phonation time in clergies was 17.8 seconds and in control group was 19 seconds. litter, pitch perturbation quotient and shimmer were significantly increased in subjective group than in control group(p<0.05), but there were no significant differences between two groups in fundamental frequency, vFo, amplitude perturbation quotient and noise to harmonic ratio. Conclusion : In the clergies using loud and forceful voice, vocal polyp and functional voice disorder findings were frequently noted in stroboscopic examination. litter and shimmer, reflecting the roughness of voice, were increased in acoustic analysis. Therefore, clergies, classified into untrained professional voice users, need professional career guidance and counseling.

• Korean Journal of Head & Neck Oncology
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• v.32 no.1
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• pp.7-11
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• 2016

Background and Objectives: Quality of voice may be deteriorated after thyroidectomy without any injury to recurrent laryngeal nerve. While there have been several studies showing the change of acoustic parameters after thyroidectomy, factors related to deteriorated voice quality have been rarely studies. In this study, we sought to analyze the factors associated to deteriorated voice quality after thyroidectomy. Materials and Methods: We made a retrospective review of 35 patients who underwent thyroidectomy for papillary thyroid carcinoma. Voice analysis including acoustic analysis, voice handicap index 10 (VHI-10), and GRBAS score was conducted before and 3 months after surgery. Patients were grouped according to the amount of increase in VHI-10 after surgery ; group A (${\Delta}VHI<7$) and group B (${\Delta}VHI{\geq}7$). Clinicopathologic factors associated to patients of group B were analyzed and changes of parameters from acoustic analysis in each group were evaluated. Results : Patients of group B were associated with age ${\geq}45$ years (p=0.025) and showed borderline association to total thyroidectomy (p=0.075) and tumor size ${\geq}1cm$ (p=0.086). Multivariate analysis demonstrated that those with age ${\geq}45$ years were independently associated to deteriorated quality of voice (p=0.014, HR=18.38). Patients of group B were also associated to significant deterioration of high pitch (p<0.001) and Grade score with borderline significance (p=0.054). Conclusion: Patients older than 45 years may have higher risk of deterioration of quality of voice after thyroidectomy based on increase of VHI-10 score (${\Delta}VHI{\geq}7$). Association with deterioration of high pitch should also be considered in these patients.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.15 no.2
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• pp.141-144
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• 2004

Background and Objectives : To compare acoustic, aerodynamic analysis of voice and intelligibility score in patients with near-total laryngectomy and implantation of Provox prothesis. Material and Methods : In order to evaluate the voice characteristics, acoustic, aerodynamic parameter and speech intelligibility were measured in 5 patients after near-total laryngectomy, 5 patients after implantation of Provox prosthesis with total bility were measured in 5 patients after near-total laryngectomy, 5 patients after implantation of Provox prosthesis with total laryngectomy and 10 adults normal speaker. Acoustic analysis was carried out using CSL and aerodynamic analysis was carried out using Aerophon II. Speech sample was recorded and 10 listener was scored for speech intelligibility using a percentage of words correctly identified. Results. Fundamental frequency($F_0$), intensity, jitter, shimmer, maximal phonation time(MPT), subglottic air pressure were used for parameters for voice analysis. There were no significant difference between two group except on fundamental frequency and shimmer. The fundamental frequency was higher in patients with near-total laryngectomy and shimmer was higher in patients after implantation of Provox prosthesis with total laryngectomy. In addition, speech intelligibility was no significant difference between two groups. Conclusion : This results confirm that near-total laryngectomy and implantation of Provox prosthesis provides good voice rehabilitation.