• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.9 no.1
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• pp.22-26
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• 1998

Uvulopalatopharyngoplasty(UPPP) is one of the most popular surgical procedure for the treatment of obstructive sleep apnea syndrome(OSAS) occurring at the level of oropharynx. However, voice changes after UPPP have been a challenging issue for the professional voice users, because even minor changes in voice quality or articulation may be critical to professional singers, teachers, and so on. Several acoustic changes after UPPP have been proposed. However, based on the authors understanding, there is no report about voice changes after UPPP in Korean. We measured the first, second and third formant frequencies of /a/, /i/, /u/ phonations in 20 adult male patients who had undergone UPPP surgery, and the nasalances of Rabbit, Baby, and Mama passages. These parameters were measured preoperatively, at 1 month and 3 months after the operation. Any subjective voice changes were asked to be reported at the posto-perative visits. The third formant(F3) of /u/ phonation was significantly reduced at postoperative 1 month measurement. The nasalance of Mama passage was singnificantly increased at postoperative 3 months measurement. No one complained of subjective changes in voice quality, timbre, articulation or speech. Even though there are no complaints about postoperative voice changes subjectively, significant changes in the formant characteristics of certain vowel and changes in the nasality after UPPP require the clinicians to be mort cautious and careful in deciding UPPP for the professional voice users.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.161-167
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• 2008

A method to compute the size of packet and the optimal way to transmit the packets are proposed in this work for the VoIP communication using the MIL-STD-188-220C, military wireless Ad-hoc protocol which is used for the amicable communications of both speeches and data between several radiotelegraph. The expected time of data transmission is estimated beforehand, and then the size of package and transmission method are decided in the consideration of VoIP speech quality for the users as well as the data transmission quality of radiotelegraph.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.3
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• pp.607-616
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• 1999

This paper proposed an improved 4.8kbps VSELP in order to keep the good quality in band-limited channel. In the most cases, it is difficult to keep the good quality at the low bit rate. In order to solve the problems, many methods are proposed, but they are not suitable to the Korean language structure because they are designed for being suitable to the foreign language structure. In experiment, we use the noseless Korean voice data. We show that the proposed 4.8kbps VSELP is not excellent to the 8kbps VSELP in SEGWSNR(Segmentally Weighted SNR), but it is the superior to the 8kbps VSELP in the MOS(Mean Opinion Score) test.

• The Journal of the Acoustical Society of Korea
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• v.20 no.1
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• pp.43-49
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• 2001

EVRC (Enhanced Variable Rate Codec) has been adopted as a standard coder for the CDMA digital cellular system in North America and Korea, and known to provide good call quality at 8kbps. In this paper, fast implementation algorithms for EVRC encoder are proposed. The proposed algorithms are based on both efficient pitch detection scheme and fast fixed codebook search algorithm. In the codebook search, computational complexity is reduced down to 70％ of the original EVRC by limiting the number of pulse position combination and by using a truncated impulse response. The proposed algorithms enable us to implement the EVRC with much smaller computational works. Also, informal subjective tests confirmed that the difference in the speech quality between the original EVRC and the proposed method was indistinguishable.

• The Journal of the Acoustical Society of Korea
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• v.21 no.4
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• pp.349-360
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• 2002

In ITU H.323 teleconference system, the RTP/RTCP protocol is offered to transfer real-time multimedia stream. Both sender and receiver hate experience in packet loss and jitter which result from network congestion over Internet. Audio quality over Internet depends on the number of lost packets and on jitter between successive packets. The goal of our study is to improve the speech quality over Internet by checking the packet loss characteristics of the network and adopting the but for control management mechanism at the receiver. We suggest a dynamic redundant audio transmission mechanism which examines the packet loss rate and uses the feedback information through RTCP.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.2
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• pp.16-21
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• 2000

Vector quantization(VQ) is widely used in many high-quality and high-rate data compression applications such as speech coding, audio coding, image coding and video coding. When the size of a VQ codebook is large, the computational complexity for the full codeword search method is a significant problem for many applications. A number of complexity reduction algorithms have been proposed and investigated using such properties of the codebook as the triangle inequality. This paper proposes a new fast VQ search algorithm that is based on a multi-stage structure for searching for the best codeword. Even using only two stages, a significant complexity reduction can be obtained without any loss of quality.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.5
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• pp.1590-1609
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• 2021

Laughter is one of the most important nonverbal sound that human generates. It is a means for expressing his emotions. The acoustic and contextual features of this specific sound are different from those of speech and many difficulties arise during their modeling process. During this work, we propose an audio laughter generation system based on unsupervised generative models: the autoencoder (AE) and its variants. This procedure is the association of three main sub-process, (1) the analysis which consist of extracting the log magnitude spectrogram from the laughter database, (2) the generative models training, (3) the synthesis stage which incorporate the involvement of an intermediate mechanism: the vocoder. To improve the synthesis quality, we suggest two hybrid models (LSTM-VAE, GRU-VAE and CNN-VAE) that combine the representation learning capacity of variational autoencoder (VAE) with the temporal modelling ability of a long short-term memory RNN (LSTM) and the CNN ability to learn invariant features. To figure out the performance of our proposed audio laughter generation process, objective evaluation (RMSE) and a perceptual audio quality test (listening test) were conducted. According to these evaluation metrics, we can show that the GRU-VAE outperforms the other VAE models.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.5
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• pp.815-836
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• 1999

The role of animal agriculture for the quality of human life has always been emphasized during 20th century and it is expected to be even more important in terms of food supplies and in providing additional functions in the future. The world human population has almost tripled during a period of half century. The world population of animals has increased 2~3 times (6 times for chicken) during the last 60 years, and the total amount of livestock products has increased 5~6 times (more than 10 times in pork) with higher annual growth rate (9%) in developing countries. Increased personal income certainly encouraged demand for animal products over grains and lower animal production costs resulted from scientific and technological advances. Similarly the production of total grains has more than doubled owing to the advances in agricultural science during the later part of the 20th century. The average life span of world people in 1950s was only 46 years, which will be increased to almost 66 years in the year 2000. Present date clearly indicate that the life span of people is proportional to their income (GNP) and/or animal protein intake. Animals can provide other resources than foods. The increase of human population indicates that the number of animals as well as per capita consumption of animal products will be increased in the 21st century. The other resources we get from animals are drafts, packing, riding, hunting and herding. Guiding the blind, protection and companionship are also examples of what we can expect from animals. In the very near future, animals will become major donors of organs, skin and producers of drugs or special functional foods. It may be concluded that animals are very closely associated and related to the quality of human life, and they are expected to remain the same way in the 21st century.

• Proceedings of the KSPS conference
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• 1996.10a
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• pp.362-366
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• 1996

This paper is generally divided in 2 parts. One is the study on vowels about korean singer's lyric song in view of Daniel Jones' Cardinal Vowel. The other is acoustic study on vowels in my singing about korean lyric song. Analysis data are KBS concert video tape and CSL's. NSP file on my singing and Informants are famous singers i.e. 3 sopranos, 1 mezzo, 2 tenors, 1baritone, and me. Analysis aim is to find out Korean 8 vowels([equation omitted]) quality in singing. The methods of descrition are used in closed vowels, half closed vowels, half open vowels, open vowels and rounded vowels, unroundes vowels and formants. The study of the former is while watching the monitor screen to stop the scene that is to be analysixed. The study of the latter is to analysis the spectrogram converted by CSL's. SP file. Analysis results are an follows: Visual and auditory korean vowels quality in singing have the 3 tendency. One is the tendency of more rounded than is usual Korean vowels. Another is the tendency of centralized to center point in Cardinal Vowel and the other is the tendency of diversity in vowel quality. Acoustic analysis is studied by means of 4 formants. Fl and F2 show similiar step in spoken. In Fl there is the same formant values. This seems to vocal organization be perceived the singign situation. The width of F3 is the widest of all, so F3 may be the characteristics in singing. In conclude, the characteristics of vowels in Korean lyric songs are seems to have the tendencies of rounding, centralizing to center point in Cardinal Vowel, diversity in vowel quality and, F3'widest width in compared with usual Korean vowels.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.61 no.12
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• pp.663-668
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• 2018

Background and Objectives The main objectives of this study were to determine the clinical usefulness of the program-assisted and real ear measurement (REM)-assisted fitting of hearing aids. Subjects and Method Fifteen participants with moderate to moderately severe hearing loss were enrolled in this study. Objective and subjective fitting results were assessed to compare the benefits between the program-assisted fitting (using a software fitting program) and the REM-assisted fitting. Real ear insertion gain (REIG), sound-field audiometry using warble tone, and Korean Hearing in Noise Test (K-HINT) were performed as objective tests. Sound quality rating was performed as a subjective test. Results In the program fitting, 48.89% of fitting points failed to come within ${\pm}10dB$ of the REIG target. In the REM fitting, however, the percentage of failure significantly decreased to 23.33% (p=0.013). In K-HINT test, the reception threshold for speech in quiet situation significantly decreased from 50.1 dB HL with the program fitting to 44.7 dB HL after the REM fitting (p<0.001). In front noise condition, signal-to-noise ratio improved from 4.53 dB to 3.50 dB with the REM fitting without statistical significance (p=0.099). In the sound quality rating, the REM fitting ($4.27{\pm}0.56$) showed a significantly better sound quality ratings than the program fitting ($3.69{\pm}0.74$) (p=0.017). Conclusion The REM fitting showed better results in both subjective and objective measurements than the program fitting.