• The Journal of the Acoustical Society of Korea
• /
• v.31 no.1
• /
• pp.39-50
• /
• 2012

A voice transformation (VT) method that can make the utterance of a source speaker mimic that of a target speaker is described. Speaker individuality transformation is achieved by altering three feature parameters, which include the LPC cepstrum, pitch period and gain. The main objective of this study involves construction of an optimal sequence of features selected from a target speaker's database, to maximize both the correlation probabilities between the transformed and the source features and the likelihood of the transformed features with respect to the target model. A set of two-pass conversion rules is proposed, where the feature parameters are first selected from a database then the optimal sequence of the feature parameters is then constructed in the second pass. The conversion rules were developed using a statistical approach that employed a maximum likelihood criterion. In constructing an optimal sequence of the features, a hidden Markov model (HMM) was employed to find the most likely combination of the features with respect to the target speaker's model. The effectiveness of the proposed transformation method was evaluated using objective tests and informal listening tests. We confirmed that the proposed method leads to perceptually more preferred results, compared with the conventional methods.

• Proceedings of the IEEK Conference
• /
• 2000.06d
• /
• pp.98-101
• /
• 2000

On CELP type Vocoders G.723.1 6.3kbps/5.3kbps Dual Rate Speech Codec, which is developed for Internet Phone and videoconferencing, uses VAD(Voice Activity Detection)/CNG (Comfort Noise Generator) in order to reduce the bit rate in a silence period. In order to reduce the bit rate effectively in this paper, we first set the boundary condition of the energy threshold to prevent the consumption of unnecessary processing time, and use three decision rules to detect an active frame by energy, pitch gain and LSP distance. To evaluate the performance of the proposed algorithm we use silence-inserted speech data with 0, 5, 10, 20dB of SNR. As a result when SNR is over 5dB, the bit rate is reduced up to about 40% without speech degradation and the processing time is additionally decreased.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.2
• /
• pp.595-602
• /
• 2015

The rotor configuration of the brushless doubly fed induction generator (BDFIG) plays an important role in its performance. In order to make the magnetomotive force (MMF) space vector in one set rotor windings to couple both magnetic fields with different pole-pair and have low resistance and inductance, this paper presents a novel wound rotor type for BDFIG with low space harmonic contents. In accordance with the principles of slot MMF harmonics and unequal element coils, this novel rotor winding is designed to be composed of three-layer unequal-pitch unequal-turn coils. The optimal design process and rules are given in detail with an example. The performance of a 700kW 2/4 pole-pair prototype with the proposed wound rotor is analyzed by the finite element simulation and experimental test, which are also carried out to verify the effectiveness of the proposed wound rotor configuration.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.54 no.10
• /
• pp.497-504
• /
• 2005

For maximum output power, wind turbines are usually controlled at the speed which is determined by the optimal tip-speed ratio. This method requires information of wind speed and the power conversion coefficient which is varied by the pitch angle control. In this paper, a new maximum output power control algorithm using fuzzy logic control is proposed, which doesn't need this information. Instead, fuzzy controllers use information of the generator speed and the output power. By fuzzy rules, the fuzzy controller produces a new generator reference speed which gives the maximum output power of the generator for variable wind speeds. The proposed algorithm has been implemented for the 3[kW] cage-type induction generator system at laboratory, of which results verified the effectiveness of the algorithm.

• Journal of Advanced Marine Engineering and Technology
• /
• v.28 no.7
• /
• pp.1131-1137
• /
• 2004

Recently there has been a remarkable increase in the number of high speed and large ships and the high power involved for propulsion of above ships has brought high pitch ratio and highly skewed propeller. The recent tendency toward highly skewed propeller has increased the load on propeller blades, and the fatigue strength of propeller blades has become the critical point in design of propellers for ships. In this paper the effect of stress ratio and skew angle on the fatigue strength of highly skewed propeller, the statistical inference on the total revolutions of highly skewed propeller for 20 years under normal sea going state. and so on have been discussed. On the basis of above discussions, the highly skewed propeller blade thicknesses by the rules of classification society and the standards of manufacturer in country were compared and reviewed.

• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.9
• /
• pp.46-53
• /
• 1996

This paper describes some research works of computer-aided design of blanking and piercing for stator and rotor parts and irregularly shaped sheet metal by press. An approach to the system is based on knowledge based rules. The process planning system by considering a blank layout for nesting of irregularly shaped sheet metal and an improved strip layout for stator and rotor parts and irregularly shaped sheet metal is implemented. Using this system, design parameters(utilization ratio, slitting width, pitch, working order, die blank shapes) are determined and output is generated in graphic forms. Knowledges for blank layout and strip layout are extracted from the plasticity theories, handbooks, relevant references and empirical know-hows of experts in blanking companies. The implemented system provides powerful capabilities for process planning of stator and rotor parts and irregularly shaped sheet metal.

• Phonetics and Speech Sciences
• /
• v.10 no.2
• /
• pp.1-6
• /
• 2018

The current study aimed to investigate the transfer of English word stress rules to the production of Korean trisyllabic words by L1 English learners of Korean. It compared English and Korean speakers' productions of seven Korean words from the corpus L2KSC (Rhee et al., 2005). To this end, it analyzed the syllable duration, intensity, and pitch. The results showed that English and Korean speakers' pronunciations differed markedly in duration and intensity. English learners produced word-initial syllables of greater intensity than Korean speakers, while Korean speakers produced word-final syllables of longer duration than English learners. However, these differences between the two speaker groups were not related to the expected L1 transfer. The tonal patterns produced by English and Korean speakers were similar, reflecting L1 English speakers' learning of the L2 Korean prosodic system.

• The Journal of Engineering Research
• /
• v.2 no.1
• /
• pp.13-21
• /
• 1997

This paper describes how to represent varations of feature parameters to improve recognition of continuous speech. For speech recognition, feature parameters, which are formant frequencies, pitches, logarithmic energies and zero crossing retes are used in general. But, their values and variations depend on speakers, for example disparities between man and woman, and on their age. It is difficult to decide a priority the value of the variation width. Hence, we try to represent this variation by introducing fuzziness and recognize a continuous speech by fuzzy inference using fuzzy production rules.

• Journal of the Korean institute of surface engineering
• /
• v.32 no.3
• /
• pp.289-296
• /
• 1999

The integration of the LSI has been greatly improved and the circuit patters on the LSI are becoming finer line and pitch. The high-density electronic packaging technology is improved. In order to realize the high-density packaging technology, the density of the circuit wiring of the printed circuit boards have also been more dense. The build-up process multilayer printed circuit board technology have a lot of vias, possibilities of the finer conductor wirings and have a freedom of capabilities of wiring design. The build-up process printed circuit boards have the wiring rules which are the pattern width: $100-20\mu\textrm{m}$, the via hole diameter: $100-50\mu\textrm{m}$. There three kinds of build-up processes as far materials and hole drilling. In this paper, the recent technology trends of the build-up printed circuit board technologies are described.

• Asia Marketing Journal
• /
• v.25 no.3
• /
• pp.148-159
• /
• 2023

As Major League Baseball (MLB)'s continuous decline in popularity has caused its game attendance to drop gradually, the league makes a desperate attempt such as game rule changes to remain relevant. Along with the introduction of new rules to make games more dynamic such as the pitch clock, bigger bases, and defensive shift limitations, it is important for MLB franchises to understand drivers for game attendance. We focus on the effect of accumulated winning performance of the two teams on game attendance, one of the key drivers of game attendance, and investigate how it is influenced by consumer and industry factors such as online search and game rule changes. We find that game attendance increases as the prior winning performance of the home (away) team increases (decreases). We also find that online search and rule changes for more dynamic games moderate the effect of winning performance on game attendance.