• 한국콘텐츠학회논문지
• /
• 제4권4호
• /
• pp.65-70
• /
• 2004

본 연구에서는 음성부호화 방식에서 피치추출 오류를 줄이고 피치간격의 변위에 적응할 수 있도록 피치간격을 정규화하지 않은 개별 피치펄스 추출법을 제안하였다. 개별피치 펄스의 추출율은 남자음성에서 $96\%$, 여자음성에서 $85\%$를 얻을 수 있었으며, 이 방법은 음성부호화방식, 음성분석, 음성합성, 음성인식 등에 활용할 수 있을 것으로 기대된다.

• 조명전기설비학회논문지
• /
• 제21권1호
• /
• pp.91-97
• /
• 2007

This paper presents a pitch angle controller of a grid-connected wind turbine system for extracting maximum power from wind and implements a modeling and simulation of the wind turbine system on MATLAB/Simulink. It discusses the maximum power control algorithm for the wind turbine and presents, in a graphical form, the relationship of wind turbine output, rotor speed, and power coefficient with wind speed when the wind turbine is operated under the maximum power control algorithm. The objective of pitch angle control is to extract maximum power from wind and is achieved by regulating the blade pitch angle during above-rated wind speeds in order to bypass excessive energy in the wind. Case studies demonstrate that the pitch angle control is carried out to achieve maximum power extraction during above-rated wind speeds and effectiveness of the proposed controller would be satisfactory.

• 음성과학
• /
• 제10권2호
• /
• pp.223-236
• /
• 2003

The purpose of this experimental study is to investigate characteristics of English pitch accents uttered by Korean speakers. Six English sentences were uttered five times by fifteen male undergraduate and graduate students from three groups, Seoul, Yongnam and Honam dialect speakers. We compared the subjects' data with the data of a native speaker of English as model pronunciation of English pitch accents. Acoustic features(Fo, duration, amplitude) were measured from sound spectrograms made by the PC Works. Results showed that (1) acoustic features of English pitch accents are Fo and duration for the native speaker and Korean speakers altogether, (2) Seoul dialect speakers uttered English pitch accents more similarly to the English native speaker than the other dialect speakers and (3) Korean speakers generally have difficulties in pronouncing L* accents. It appears that Korean speakers have more problems in pronouncing L* accents than H* accents.

• 음성과학
• /
• 제15권3호
• /
• pp.175-181
• /
• 2008

The aim of this study was to survey 'voice preference' of children from among three voice pitches, which are high-pitch, mid-pitch and low pitch, and understand acoustic characteristics of the best voice chosen. To record distinctive pitches, Dr. Speech(ver. 4.0 Tiger Electronics) was used and we analyzed their choices. Also, we measured subglottal air pressure in aerodynamic analyze and phonatory aerodynamic system(Model 6600, KAY) was used. As a result children preferred to the low-pitch yet there was not any difference by sex. We fined them to prefer higher HNR voice to lower jitter and shimmer voice rate.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
• /
• pp.159-161
• /
• 2001

This study is for the pitch control of blade, used in most horizontal-axis wind turbine systems, to sustain the maximum power output supplied to grid. The control of a blade can be divided into a stall regulation and a pitch control methods. The stall regulation method using an aerodynamic stall is simple and cheap, but it suffers from fluctuation of the resulting power. Pitch control method is mechanically and mathematically complicated, but the control performance is better than that of the stall regulation method. In this paper 2.5MW MOD-2 wind turbine system is adopted to be controlled by a pitch controller with PI method. The simulation performed by MA TLAB will show the variation of frequency, generator output, and pitch angle.

• 한국생산제조학회지
• /
• 제25권3호
• /
• pp.164-170
• /
• 2016

A proposed pneumatic cylinder-driven roll feeder and an air press were designed to be operated automatically by a PLC. The accuracy of the intermittent feed pitch of the roll feeder was evaluated by measuring lengths of cut-offs of a strip stock by a digimatic vernier caliper. At each predetermined feed pitch, the proposed roll feeder was tested 100 times by varying the feed/cut intervals as 2.0/1.5, 3.0/2.0, and 3.5/2.5 s as test sets. The lengths of the cutoffs of the strip stock ranged from 9.89-10.34, 12.1-12.65, and 15.21-15.67 mm at the predetermined 10, 12, and 15 mm feed pitch, respectively, among the total of 300 samples in each feed pitch, regardless of the feed/shear interval. Therefore, the feed/cut interval at each selected feed pitch was found to have no effect on the accuracy of the intermittent advancing of the strip stock.

• 말소리와 음성과학
• /
• 제2권1호
• /
• pp.33-39
• /
• 2010

This study investigates the effect of pitch range reset in Korean listeners' processing of syntactically ambiguous participle structures. Unlike Japanese and English,in Korean, the downtrend or the reset of pitch range does not consistently differentiate Accentual Phrases (AP), a lower level of phrasing, from Intonational Phrases (IP), a higher level of phrasing. Therefore, we explore Korean listeners' comprehension patterns for syntactically ambiguous speech strings varying in 1) the relative height of F0 peaks across prosodic units, and 2) the types of prosodic phrasing, to see whether pitch range reset informs the recovery of syntactic structure even though it is not reflected in the intonational hierarchy in Korean. The results show that the hierarchical level of prosodic phrasing affects the parsing pattern of syntactic ambiguity. The pitch range reset also cued the location of syntactic boundaries, but this effect was confined to phrases across AP.

• 말소리와 음성과학
• /
• 제6권3호
• /
• pp.101-108
• /
• 2014

This study investigates the relation among pitch range differences, speech rate and realization of stress. To identify the realization of the stress, vowel formants and durational differences of stressed and unstressed vowels are measured. The Korean learners were asked to read a textbook passage which includes nine sentences. The major results indicate that: (1) Korean speakers' pitch range is less than 50% of the native speakers; (2) There is a significantly negative relation between high-low pitch range and speech rate; (3) The vowel qualities and durations of the stressed and unstressed vowels are related to the speech rate. But these are not related to the high-low pitch range.

• Carbon letters
• /
• 제6권3호
• /
• pp.173-180
• /
• 2005

In this study, AR (aromatic resin) pitch was employed as the matrix-precursor for carbon/carbon composite because it exhibits much higher coke yield than coal tar pitch. As a result, a fabrication process of carbon/carbon composites can be shortened. It has been known that the pitches may cause swolling problem during the carbonization process. In order to restrain the swelling occurrence, a small quantity of carbon black was added to the AR pitch. Due to addition of carbon black the swelling was decreased largely and the perform can be infiltrated with the AR pitch. The densification efficiency of the performs was compared with various matrix-precursors. The coke yield of matrixprecursors, the morphology and the degree of graphitization of carbon matrix were analyzed.

• 한국생산제조학회지
• /
• 제24권3호
• /
• pp.355-362
• /
• 2015

Test procedure for the design verification of wind turbine pitch and yaw bearings has been developed. Test items were selected to evaluate operational reliability of pitch and yaw bearings by considering loading and operational conditions, and by analyzing the design criteria of pitch and yaw bearings. The developed test items consisted of preliminary test, fatigue load test, extreme load test, low temperature environmental test and dismantling inspection after all the test were completed. Because it reflects the actual operational conditions of the pitch and yaw bearings, the developed test procedure has high reliability and can verify the basic design considerations in the international standard and guidelines.