• The Journal of the Acoustical Society of Korea
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• v.16 no.4
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• pp.35-41
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• 1997

Speech database is an indispensable part of speech research. Speech database is necessary to use in speech research and development processes, and to evaluate performances of various speech-processing systems. To use speech database for common purpose, it is necessary to design utterance list that has all the possible phonetical events in minimal number of words, and is independent of tasks. To meet those restrictions this paper extracts PBW set from large text corpus. Speech database that was constructed using PBW set for utterance list and its properties are described in this paper.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.21-24
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• 1999

본 논문에서는 가변어휘 음성인식기의 성능개선 작업에 관한 내용을 기술하고 있다. 묵음을 포함한 총 40개의 문맥독립 음소모델을 사용한다. LDA 기법을 이용하여 동일차수의 특징벡터내에 보다 유용한 정보를 포함시키고, likelihood 계산시 가우시안 분포와 mixture weight에 대한 가중치를 달리 함으로써 성능향상을 볼 수 있었다. ETRI POW 3848 DB만을 사용하여 실험한 경우, $21.7\%$의 오류율 감소를 확인할 수 있었다. 잡음환경 및 어휘독립환경을 고려하여 POW 3848 DB와 PC 168 DB 및 PBW445 DB를 사용한 실험도 행하였으며, PBW 445 DB를 사용한 어휘독립 인식실험의 경우 $56.8\%$의 오류율 감소를 얻을 수 있었다.

• Journal of Drive and Control
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• v.6 no.1
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• pp.14-20
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• 2009

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.3
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• pp.431-438
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• 2014

The study was carried out in order to verify the effects of piglets' weight at birth on their surface temperature change (ST) after birth, and its relationship with ingestion time of colostrum. Piglets from four different sows were weighed at birth and divided into a totally randomized design with three treatments according to birth weight (PBW): T1 - less than 1.00 kg, T2 - 1.00 to 1.39 kg, and T3 - higher than or equal to 1.40 kg. The time spent for the first colostrum ingestion was recorded (TFS). Images of piglets' surface by thermal imaging camera were recorded at birth (STB) and 15, 30, 45, 60, and 120 min after birth. The air temperature and relative humidity were recorded every 30 min and the indexes of temperature and humidity (THI) were calculated. A ST drop after 15 min from birth was observed, increasing again after sixty minutes. Positive correlations were found between the PBW and the ST at 30 and 45 min after birth. The PBW was negatively correlated with the TFS. The THI showed high negative correlations (-0.824 and -0.815) with STB and after 15 min from birth. The piglet's surface temperature at birth was positively correlated with temperature thereof to 15 min, influencing therefore the temperatures in the interval of 45 to 120 min. The birth weight contributes significantly to postnatal hypothermia and consequently to the time it takes for piglets ingest colostrum, requiring special attention to those of low birth weight.

• The Journal of the Acoustical Society of Korea
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• v.23 no.5
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• pp.383-389
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• 2004

In this paper. we propose the bias compensation methods and the eigenvoice method using the mean of dimensional eigenvoice to improve the performance of rapid speaker adaptation based on eigenvoice under mismatch between training and test environment. Experimental results for vocabulary-independent word recognition task (using PBW 452 DB) show that the proposed methods yield improvements for small adaptation data. We obtained about 22∼30% relative improvement by the bias compensation methods as amount of adaptation data varied from 1 to 50, and obtained 41% relative improvement in error rate by the eigenvoice method using the mean of dimensional eigenvoice with only single adaptation word.

• Journal of the Korea Computer Industry Society
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• v.2 no.6
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• pp.867-874
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• 2001

In this paper, considering the pronunciation characteristic of Korean, recognition units which can shorten the recognition time and reflect the coarticulation effect simultaneously are suggested. These units are composed of monophone and hipbone ones. Monophone units are applied to the vowels which represent stable characteristic. Biphones are used to the consonant which vary according to adjacent vowel. In the experiment of word recognition of PBW445 database, the compound units result in comparable recognition accuracy with 57％ speed up compared with triphone units and better recognition accuracy with similar speed. In addition, we can reduce the memory size because of fewer units.

• The Journal of the Acoustical Society of Korea
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• v.22 no.5
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• pp.403-407
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• 2003

Recently, eigenvoice approach has been widely used for rapid speaker adaptation. However, even in the eigenvoice approach, Performance improvement using very small amount of adaptation data is relatively small in comparison with that using somewhat large adaptation data because the reliable estimation of weights of eigenvoice is difficult. In this paper, we propose a rapid speaker adaptation method based on eigenvoice using the weight distribution characteristics to improve the performance on a small adaptation data. In the Experimental results on vocabulary-independent word recognition task (using PBW 452 database), the weight threshold method alleviates the problem of relatively low performance for a tiny small adaptation data. When single adaptation word is used, word error rate is reduced about 9-18% by the weight threshold method.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.2
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• pp.125-131
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• 2017

In order to develop test and performance analysis techniques for a CRP propulsion, a CRP dynamometer which can be installed inside the model ship was designed and manufactured. The object ship was the 16000TEU container carrier, which has test results for the single propeller. The design concept of the present CRP is that forward & after propellers have the same power ratio and their RPM ratio is 0.75:1. To begin with, we checked the performance of the CRP dynamometer through the calibration and then installed it inside the model ship. After the model ship setup including the design CRP and the rudder in the Large Cavitation Tunnel(LCT), a series of model tests composed of power ratio check, propeller behind wake(PBW) test, cavitation observation and pressure fluctuation tests was conducted. Through the model test and data analysis for CRP, the experimental technique was established and the improved method for CRP design was suggested.

• Polymer(Korea)
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• v.24 no.2
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• pp.149-158
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• 2000

Oil-absorptive expanded polyurethane (EPU) was prepared with a lypophilic polyol, polypropyleneglycol (PPG) as the soft segment, and toluenediisocyanate (TDI) and $H_2O$ as the hard segment. PPGs haying various average molecular weights ((equation omitted) : 1000, 2000, 3000) were employed to investigate that the soft segment content was consequent on the oil-absorptivity and the mechanical properties of the EPUs. As (equation omitted) of PPG was decreased from 3000 to 1000, the oil-absorptivity and the tensile strength of the EPUs increased from 1460 to 3010% and from 0.26 to 0.55 $kg_{f}$ /$cm^2$ respectively. As the hard segment content ratio, ${\gamma}$ ([NCO]/[OH]) was increased from 1.0 to 1.2, the tensile strength of the EPUs increased from 0.56 to 0.95 $kg_{f}$ /$cm^2$, due to the formation of allophanate and/or biuret bondings. However, as the surfactant (S-A) content was increased from 1.0 to 2.5 pbw, the oil-absorptivity was decreased from 3634 to 3312%, due to the formation of closed cell structures.

• The Journal of the Acoustical Society of Korea
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• v.38 no.6
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• pp.651-660
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• 2019

The present study aims to find out the necessary speech sound level which can satisfy with the speech intelligibility in a noisy classroom environments. For this, auralized materials were made to undertake listening tests with 27 people. Speech intelligibility tests were carried out using both Consonant-Vowel-Consonant (CVC) and Phonetically Balanced Words (PBW) methods. Signal to noise ratio was changed by 5 dB for each test. As a result, it was found that speech intelligibilities are increasing with larger Signal to Noise Ratio (SNR). It was also found that there is a lot of difference of speech intelligibilities by SNR for syllables (CVC) with the Reverberation Time (RT) of 1.5 s. However, any significant difference was not found for words (PBW) in the case with RTs of below 0.8 s. Also, it was revealed through the 2-way analysis of variance (ANOVA) test that SNR is the only attentive factor which can affect the Korean speech intelligibilities for both PBW and CVC methods. Therefore, RTs below 0.8 s could be the acoustic criteria for classroom which can minimize the effects of noise. In the case with RTs larger than 0.8 s, much larger SNR is needed to give sufficient speech intelligibility.