• Speech Sciences
• /
• v.6
• /
• pp.103-117
• /
• 1999

This paper suggests that the onset-coda asymmetry found in languages like Korean and others should be dealt with in terms of one acoustic feature rather than other articulatory features, claiming that the acoustic feature involved here is [noise], i.e., 'aperiodic waveform energy'. It determines the structural well-formedness of the languages in question whether a coda ends in [noise] or not, regardless of the intensity, the frequency, and the time duration of the [noise]. Fricatives, affricates, aspirated stops, tense stops, and released stops are all disallowed in the coda position due to the acoustic feature [noise] they, commonly end with if they were, posited in the coda. The proposal implies that the three seemingly separate prohibitions of consonants in the coda position -- i) no fricatives/affricates, ii) no aspirated/tense stops, and iii) no released stops -- are directly correlated with each other. Incorporation of the one acoustic feature [noise] in the feature theory enables us to see that the aspects of onset-coda asymmetry are derived from one single source: ban, of [noise] in the coda.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2001.04a
• /
• pp.61-65
• /
• 2001

A new flaw detection technique using by SH angle beam method has been discussed. The SH-wave is horizontally polarized shear wave and the surface SH wave has a characteristic of traveling along near surface layer. The surface SH wave technique is valuable for the detection of fatigue cracks at fillet weld heels which cannot be detected by other ultrasonic technique such as angle beam technique and The dispersion curves of it has simple characterization. In this work, using these beneficial chraterization, quality evaluation of spot weld with ultrasonic sound intensity of SH-wave passing through nugget area of spot weld are verified experimentally.

• Proceedings of the KSPS conference
• /
• 2007.05a
• /
• pp.170-172
• /
• 2007

The purpose of this study was to examine the syllable structures of ten Korean numeric sounds produced by ten subjects of the same age. Each sound was normalized and divided into onset, vowel, and coda sections. Then, acoustical measurements of each syllable were done to compare the ten sounds. Results showed that there was not much deviation from the grand average duration and intensity for the majority of the sounds except the two diphthongal sounds on which their boundary points varied among the speakers. Some syllable boundaries were quite obvious while others were ambiguous. There seemed some tradeoff among the syllable components depending on their acoustic features.

• Journal of KSNVE
• /
• v.8 no.1
• /
• pp.187-194
• /
• 1998

In order to predict the train noise propagation from a level railroad, this paper presents the model of train noise source and the prediction model based on the results by using the sound intensity method. The prediction model gives the effects of geometric attenuation, ground attenuation, and barrier attenuation of noise. There are several principal assumption in developing model: (a) the train noise is primarily rolling noise; (b) the rail head and wheels are in good condition; (c) the height of source is 10cm above track; (d) the directivity pattern of train noise sources is a dipole source. Calculated results based on this model are compared with available field data and good agreement has been obtained.

• Journal of KSNVE
• /
• v.6 no.6
• /
• pp.835-842
• /
• 1996

To identify the locations and strengths of acoustic sources, one may use a microphone line array. Apparent advantage of the source identification method utilizing a line array is that it requires less measurement points than intensity method and holography. This method is based on the information of magnitude and phase difference between pressure signals at each microphone. Since those differences are dependent on the source model, we have to assume them such as plane, monopole, etc. In this paper the conventional source identification methods such as beamforming method and MUSIC method are briefly reviewed by modeling a source as plane and spherical wave, then a modified method is introduced. This can be applied to sound field which may by either coherent or incoherent. Typical simulations and experiment are performed to confirm this identification method.

• 유체기계공업학회:학술대회논문집
• /
• 2005.12a
• /
• pp.789-795
• /
• 2005

This study proposes a modified bifurcation model with a computational fluid analysis according to variation of a bifurcation geometry. FLUENT is used for a calculation of the head losses in case of a generation and a pumping. The pressure, velocity field and turbulent intensity are simulated in a bifurcation. With consideration about these flow properties, we propose the modified model to improve a flow efficiency and reduce a sound. The proposed model is able to cut down a head loss by 45% when a generation and 36% when a pumping.

• Journal of Veterinary Clinics
• /
• v.15 no.2
• /
• pp.410-416
• /
• 1998

These experiments were designed to evaluate the possibility of brain-stem auditory evoked responses(BAER) as a diagnostic tool for deafness in dogs. The BAER was recorded from three different groups of dogs; the normal dogs,'dog with otitis externa and dogs with unilateral destruction of cochlear. BAER of the normal dogs was consisted of distinct five peaks(I, II, III-IV, V). Furthermore, the clear shapes of waveform were observed at 85 dB. The latency of BAER was increased with reducing the intensity of sound-stimulus. The highest threshold of BAER was measured at 2 KHz with 10-30 dB. Dog with otitis externs demonstrated unclear shapes of BAER compared to the that of normal dogs. In the dogs with unilateral destruction of cochlear, the flat and indistinct waveform of BAER was recorded from the cochlear destroyed ear while that of BAER from normal side of ears did not show any differences from the normal BAER. These results indicate that the BAER can be clinically used in order to diagnose the deafness in dogs.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.2 s.95
• /
• pp.225-231
• /
• 2005

This paper presents a design method for the structural-acoustic coupled radiator that can emit sound in the desired direction. A coupled system that has a finite space and a semi-infinite space separated by two flexible walls and an opening is considered. An objective function is selected to maximize radiation power on a main axis and minimize a side lobe level. To get initial values, prediction of a pressure distribution on field points and radiation pattern of the structural-acoustic coupling system is shown at a coupled-resonant frequency. Three different optimization methods are adapted to design the coupled radiator. Pressure and intensity distribution of the designed radiator is presented.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.17 no.10
• /
• pp.950-957
• /
• 2007

This paper considers acoustic characteristics of silencer within a dry vacuum pump. The main objective is to reduce noise in dry vacuum pump using the new designed silencer. First, SPL and sound intensity are measured for noise source identification and the new model silencer is designed corresponding to noise characteristics. 4-pole parameters are used to predict the transmission loss which is one of the interest characteristics of the new silencer. The calculated transmission loss is then used to change main effective factor and optimal value is selected by using design of experiment. By conducting an experiment, it is proved that the new designed silencer has reduced noise level by 6 dB(A) more than the original one.

• Journal of Information Technology Applications and Management
• /
• v.26 no.3
• /
• pp.29-41
• /
• 2019

As users' interests of cryptocurrency has been increased, investment volume of it also increases. In the cryptocurrency market, it cannot always be distributed homogenous information to all investors, similar to the stock market because it reflects the characteristics of a market microstructure. Cryptocurrency traders, thus, like stock investors, can experience the information asymmetry in the market and cannot but help to depend on private information. The purpose of this study is to estimate the trading intensity of informed traders and uninformed traders among cryptocurrency investors around the world based on PIN (Probability of Informed Trading). We have an aim to compare the difference of information asymmetry according to the ten types of cryptocurrency. The results of this study are expected to prevent the continuous increase of suspicious transactions related to cryptocurrency and contribute to the development of a sound cryptocurrency market.