• Phonetics and Speech Sciences
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• v.6 no.1
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• pp.21-30
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• 2014

This study aims to discuss pitch slope on Korean intonation curve in spontaneous speech data. For this study, 656 utterances were taken in the spoken corpus and used 'close-copy stylization'. And then the physical feature of pitch movements was extracted for the study. The pitch slope was calculated on the basis of time and pitch range in each utterance. As a result, the average and distribution of pitch slope is similar between men and women in the range of the pitch movement except for essential differences. The slope of pitch movement confirms that there are no differences between men and women. Pitch slope on a scale of -10 to 10 is 90% of the entire pitch slope; pitch slope that moves by time scale without curve is 33.1%; pitch slope that moves half of the pitch bandwidth during the average time for pitch movement is 23.4%; pitch slope that moves 100% of pitch bandwidth during a half of the average time for pitch movement is 10.4%. Those results imply the possibility of standardization methods of Korean intonation by pitch slope.

• Phonetics and Speech Sciences
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• v.6 no.3
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• pp.131-138
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• 2014

A close-copy stylization of intonation curve was used for an acoustical analysis of emotional speech. For the analysis, 408 utterances of five emotions (happiness, anger, fear, neutral and sadness) were processed to extract acoustical feature values. The results show that certain pitch point features (pitch point movement time and pitch point distance within a sentence) and sentence level features (pitch range of a final pitch point, pitch range of a sentence and pitch slope of a sentence) are affected by emotions. Pitch point movement time, pitch point distance within a sentence and pitch slope of a sentence show no significant difference between male and female participants. The emotions with high arousal (happiness and anger) are consistently distinguished from the emotion with low arousal (sadness) in terms of these acoustical features. Emotions with higher arousal show steeper pitch slope of a sentence. They have steeper pitch slope at the end of a sentence. They also show wider pitch range of a sentence. The acoustical analysis in this study implies the possibility that the measurement of these acoustical features can be used to cluster and identify emotions of speech.

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.79-90
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• 2014

An intonation curve stylization was used for an acoustical analysis of English speech. For the analysis, acoustical feature values were extracted from 1,848 utterances produced with normal and fast speech rate by 28 (12 women and 16 men) native speakers of English. Men are found to speak faster than women at normal speech rate but no difference is found between genders at fast speech rate. Analysis of pitch point features has it that fast speech has greater Pt (pitch point movement time), Pr (pitch point pitch range), and Pd (pitch point distance) but smaller Ps (pitch point slope) than normal speech. Men show greater Pt, Pr, and Pd than women. Analysis of sentence level features reveals that fast speech has smaller Sr (sentence level pitch range), Sd (sentence duration), and Max (maximum pitch) but greater Ss (sentence slope) than normal speech. Women show greater Sr, Ss, Sp (pitch difference between the first pitch point and the last), Sd, MaxNr (normalized Max), and MinNr (normalized Min) than men. As speech rate increases, women speak with greater Ss and Sr than men.

• Tribology and Lubricants
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• v.24 no.5
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• pp.221-227
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• 2008

This paper presents a step-by-step design of noncircular gears. From the diagram of angular velocity ratio of a noncircular gear pair, the pitch curves of the two mating gears are determined, and the perimeter of the pitch curve has been divided into equal-length segments by the number of teeth. A master tooth profile, which is a composite curve of circular arcs that represents involute, has been introduced. A noncircular gear pair has been designed by imposing the master tooth on the divided points of the pitch curve, and a full fillet has been achieved between neighbour teeth. Thus, the whole profile of the noncircular gear is a composite curve of arcs only, and consequently NC codes for wire EDM can be easily generated.

• Tribology and Lubricants
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• v.28 no.1
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• pp.27-32
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• 2012

Oval gears are typical kinds of non-circular gears and are widely used in flow meters. This paper presents a tooth profile design of an oval gear according to the curvature of the pitch curve. The length of the pitch oval is divided by the number of teeth and the curvature of the divided points is obtained. The tooth profile is designed on the circle of the curvature as if it is the pitch circle of a gear. The teeth of the oval gear have the same module and pressure angle, but the pitch circle of each tooth differs in size. Thus, the teeth on the divided points of the pitch oval are different in shape. This type of oval gear will improve the meshing properties.

• Journal of Wind Energy
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• v.2 no.1
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• pp.82-89
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• 2011

his dissertation is on power control system for MW-class wind turbine. Especially, the control purpose is reduction in electrical power and rotor speed. The base control structure is power curve tracking control using variable speed variable pitch operational type. For the reduction of fluctuations, more control algorithm is needed in above rated wind conditions. Because general pitch control system is low dynamic response as compared with the wind speed change. So, this paper introduces about the pitch feed forward control to minimize fluctuations of the electrical power and rotor speed. To maintain rated electrical power, the algorithm of feed forward control adds feed forward pitch amount to the pitch command of power curve tracking control. The effectiveness of the feed forward control is verified through the simulation.

• Journal of Power System Engineering
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• v.18 no.1
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• pp.22-31
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• 2014

This paper introduced the new calibration algorithm of a straight-type five-hole pressure probe necessary for calculating three-dimensional flow velocity components. The new velocity data reduction method using both a commercial two-dimensional curve-fitting program and the zone partition method of a calibration map was firstly introduced in this study. This new calibration method can be applied up to the wide flow angle of ${\pm}80^{\circ}$ despite of using a five-hole pressure probe because this data reduction method showed a comparatively good performance in calculating yaw and pitch angles from the calibration map.

• Tribology and Lubricants
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• v.23 no.4
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• pp.149-155
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• 2007

The CAD model of a elliptical gear for wire cutting has been developed. The rolling contact of pitch ellipses whose rotation axes coincide with their focus has been analyzed, and the perimeter of the pitch ellipse has been divided into equal-length segments by the number of teeth. A master tooth profile, which is a composite curve of circular arcs that represents involute, has been introduced. The elliptical gear has been designed by imposing the master tooth on the divided points of the pitch ellipse, and a full fillet has been achieved between neighbour teeth. Thus, the whole profile of an elliptical gear is a composite curve of arcs only, and consequently NC codes for wire cutting can be easily generated. Furthermore, a computer simulation program is developed to verify the mesh of the elliptical gear.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.5
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• pp.96-101
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• 1999

This study suggests an algorithm for tooth profile generation of free from curve involute gear, a special gear of which the pitch line is a free curve instead of a circular one. For the first, a methodology for calculation of the tooth curve is developed and formulated Then the formulated algorithm, is programmed for manufacturing and verified by computer graphics. Next the calculated results as changed in to NC codes to apply to wire electric discharge machine(WEDM). Finally, the machined gear is examined in engagement with a standard involute gear.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.861-866
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• 1996

The Non-Circular Gears is more advantage than other machinery using link and cam in the automation equipment. We designed Non-Circular Gears for a velocity of inequalty rotational equipment according to the variation of pressure angle, radius of curvature etc., and studied about pitch curve.