• The Journal of the Acoustical Society of Korea
• /
• v.14 no.4
• /
• pp.38-45
• /
• 1995

In this paper a way to improve the performance of the long term prediction is proposed, which adopts the Multi-band Excitation (MBE) method in addition to the Code-Excited Linear Prediction (CELP) method at low bit rates below 4.8 kbps. In the proposed method, the multiband long term prediction is performed on the periodic components which still remain after the long term prediction of the conventional CELP method. At this point, the whole frequency region is divided into subbands whose size is equal to the spacing between the harmonics of the fundamental frequency, and the periodic multiband excitation signals. are represented as the sum of sine waves approximately as large as the spectrum of the excitation signals, so that the actual characteristics of the excitation signals can be better taken into account. To evaluate the performance of the proposed method, computer simulation is performed at 4.8 kbps. The 4.8 kbps DoD CELP and the 4.4 kbps IMBE were chosen as the reference vocoders for the speech quality measure. The result of the perceptual speech quality measure showed that the performance of the proposed method is better than that of the 4.8 kbps DoD CELP vocoder, and similar to that of the 4.4 kbps IMBE vocoder.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.31 no.2
• /
• pp.71-77
• /
• 2020

Background and Objectives OperaVOXTM (Oxford Wave Research Ltd.) is a portable voice analysis software package designed for use with iOS devices. As a relatively cheap, portable and easily accessible form of acoustic analysis, OperaVOXTM may be more clinically useful than laboratory-based software in many situations. The aim of this study was to evaluate the agreement between OperaVOXTM and Multi-Dimensional Voice Program (MDVP; Computerized Speech Lab) to assess voice quality before and after laryngeal microsurgery in patient with vocal polyp. Materials and Method Twenty patients who had undergone laryngeal microsurgery for vocal polyp were enrolled in this study. Preoperative and postoperative voices were assessed by acoustic analysis using MDVP and OperaVOXTM. A five-seconds recording of vowel /a/ was used to measure fundamental frequency (F0), jitter, shimmer and noise-to-harmonic ratio (NHR). Results Several acoustic parameters of MDVP and OperaVOXTM related to short-term variability showed significant improvement. While pre-operative value of F0, jitter, shimmer, NHR was 155.75 Hz (male: 125.37 Hz, female: 183.37 Hz), 2.20%, 6.28%, 0.16, post-operative values of these parameter was 164.34 Hz (male: 129.42 Hz, female: 199.26 Hz), 2.15%, 5.18%, 0.14 Hz in MDVP. While pre-operative value of F0, jitter, shimmer, NHR was 168.26 Hz (male: 135.16 Hz, female: 201.37 Hz), 2.27%, 6.95%, 0.26, post-operative values of these parameters was 162.72 Hz (male: 128.267 Hz, female: 197.18 Hz), 1.71%, 5.36%, 0.20 in OperaVOXTM. There was high intersoftware agreement for F0, jitter, shimmer with intraclass correlation coefficient. Conclusion Our results showed that the short-term variability of acoustic parameters in both MDVP and OperaVOXTM were useful for the objective assessment of voice quality in patients who received laryngeal microsurgery. OperaVOXTM is comparable to MDVP and has high intersoftware reliability with MDVP in measuring the F0, jitter, and shimmer

• The Journal of the Korea institute of electronic communication sciences
• /
• v.8 no.12
• /
• pp.1793-1802
• /
• 2013

Various approaches for sound source segregation have been proposed. Among these approaches, frequency domain binaural model(FDBM) has the advantages of low computational load and effective howling cancellation. A binaural hearing assistance system based on FDBM has been proposed. This system can enhance desired signal based on the directivity information. Although FDBM has been evaluated in terms of signal-to-noise ratio (SNR) and coherence function, the evaluation results do not always agree with the human impressions. These evaluation methods provide physical measures, and do not take account of perceptual aspect of human being. Considering a binaural hearing assistance system as a one of major applications, the quality of segregated sound should keep level enough. In the paper, signal segregation performance by means of FDBM is evaluated by three objective methods, i.e., SNR, coherence and Perceptual Evaluation of Speech Quality(PESQ), to discuss the characteristic of FDBM on the sound source segregation performance. The simulation's evaluation results show that FDBM improves the quality of the left and right channel signals to an equivalent level. And the results suggest the possibility that PESQ provides a more useful measure than SNR and coherence in terms of the segregation performance of FDBM. The evaluation results by PESQ show the effects from segregation parameters and indicate appropriate parameters under the conditions. In the paper, signal segregation performance by means of FDBM is evaluated by three objective methods, i.e., SNR, coherence and PESQ, to discuss the characteristic of FDBM on the sound source segregation performance. The simulation's evaluation results show that FDBM improves the quality of the left and right channel signals to an equivalent level. And the results suggest the possibility that PESQ provides a more useful measure than SNR and coherence in terms of the segregation performance of FDBM. The evaluation results by PESQ show the effects from segregation parameters and indicate appropriate parameters under the conditions.

• Journal of Biomedical Engineering Research
• /
• v.31 no.1
• /
• pp.20-26
• /
• 2010

The aim of this study was to test the feasibility of a wireless transceiver that can be inserted into the ear canal. The wireless technology could minimize the cosmetic problems of patients, and it can be applied to binaural hearing aids for improving speech perception. In order to implement the ear canal insertable transceiver, simple finite-difference time-domain (FDTD) simulations were carried out to determine the feasibility, and the hardware of the transceiver was implemented within the ear shell. The size of the implemented transceiver was only $7{\times}7mm$, and it could successfully transmit signals to external devices. In order to measure the radiation pattern, a simple RF phantom was used, and the maximum attenuation from the phantom was observed to be 23 dB when the reference antenna was placed at a distance of 2 m from the transmitter.

• Child Health Nursing Research
• /
• v.7 no.1
• /
• pp.21-34
• /
• 2001

The impact of childhood experience has lifelong significance on subsequent health and development. Especially, the experience of infant is mostly affected by the quality of parental care and rearing environment. But the new mothers usually do not know what to do because of the lack of experience in these days. Therefore, an educational program regarding maternal role would be necessary. This study was conducted to evaluate the effectiveness of the maternal role education program for mother-infant interaction, child-rearing environment, and infant development. Non-equivalent control group time-series design was used, and Barnard's mother-infant interaction model was used as a conceptual framework of this study. The subjects were the healthy infants weighing over 2,500gm at birth, whose gestational age was more than 37 weeks, and their mothers. The final sample consisted of 19 mother-infant dyads for intervention group and 18 dyads for control group. Data were collected from March 15th to September 3rd in 1999. For the intervention group, programmed education which focused on mother-infant interaction, breast feeding, and infant care was provided before discharge. Telephone counselling was provided within one week after discharge. Home visiting for maternal role education was provided twice, one month and three months postpartum. For the control group, home visiting was also conducted but only for data collection. The data were analyzed using chi-square test and t-test to test the equivalence of two groups, and the effectiveness of intervention program was determined with repeated measure ANCOVA and t-test. The results were as follows: 1. Significant differences were found in mother-infant interaction between two groups(p=.000). It indicates that intervention program was effective in improving mother- infant interaction. In subscale analysis, four out of six subscale showed significant differences between the groups: sensitivity to cues (p=.000), social-emotional growth fostering (p=.000), cognitive growth fostering(p=.000) in mothers, and responsiveness to caregiver (p=.019) in infants. 2. The difference in the mean score of childrearing environment (HOME) between the intervention group and control group was significant(p=.003). When each subscale of HOME was examined individually, intervention group showed significantly higher scores in the diversity of stimulation(p=.000), and mother's involvement(p=.001). 3. Three-month-Infants of the intervention group showed higher GQ in the Griffiths mental development scale(p=.026). In subscale analysis, significant differences were found in the personal-social(p=.005), and the hearing and speech(p=.003). In conclusion, the maternal role education program proved to be effective in promoting the mother-infant interaction, organizing the childrearing environment, and fostering the infant development. These results are very meaningful that we found maternal role education necessary for normal infants' mothers, and that nurses can make a great contribution in promoting health of infants and mothers.