• 음성과학
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• 제8권1호
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• pp.7-19
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• 2001

The acoustic parameters of nine Korean numbers were analyzed by Praat, a speech analysis software, and synthesized by SenSynPPC, a Klatt formant synthesizer. The overall intensity, pitch and formant values of the numbers were modified dynamically by a step of 1 dB, 1 Hz and 2.5% respectively. The study explored the sensitivity of listeners to changes in the three acoustic parameters. Twelve subjects (male and female) listened to 390 pairs of synthesized numbers and judged whether the given pair sounded the same or different. Results showed that subjects perceived the same sound quality within the range of 6.6 dB of intensity variation, 10.5 Hz of pitch variation and 5.9% of the first three formant variations. The male and female groups showed almost the same perceptual ranges. Also, an asymmetrical structure of high and low boundary was observed. The ranges may be applicable to the development of a speaker identification system while the method of synthesis modification may apply to its evaluation data.

• International Journal of Naval Architecture and Ocean Engineering
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• 제5권3호
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• pp.392-403
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• 2013

For the analysis of radiating noise problems in medium-to-high frequency ranges, the Energy Flow Boundary Element Method (EFBEM) was developed. EFBEM is the analysis technique that applies the Boundary Element Method (BEM) to Energy Flow Analysis (EFA). The fundamental solutions representing spherical wave property for radiating noise problems in open field and considering the free surface effect in underwater are developed. Also the directivity factor is developed to express wave's directivity patterns in medium-to-high frequency ranges. Indirect EFBEM by using fundamental solutions and fictitious source was applied to open field and underwater noise problems successfully. Through numerical applications, the acoustic energy density distributions due to vibration of a simple plate model and a sphere model were compared with those of commercial code, and the comparison showed good agreement in the level and pattern of the energy density distributions.

• Journal of the Optical Society of Korea
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• 제19권5호
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• pp.537-543
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• 2015

Liquid crystal displays (LCDs) have slow responses, so motion blurs are often perceived in fast moving scenes. To reduce this motion blur, we propose a novel method of robust motion compensated frame interpolation (MCFI) based on bidirectional motion estimation (BME) and weight-overlapped block motion compensation (WOBMC) with variable block sizes. In most MCFI methods, a static block size is used, so some block artefacts and motion blurs are observed. However, the proposed method adjusts motion block sizes and search ranges by comparing matching scores, so the precise motion vectors can be estimated in accordance with motions. In the MCFI, overlapping ranges for WOBMC are also determined by adjusted block sizes, so the accurate MCFI can be performed. In the experimental results, the proposed method strongly reduced motion blurs arisen from large motions, and yielded interpolated images with high visual performance and peak signal-to-noise ratio (PSNR).

• 설비공학논문집
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• 제10권5호
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• pp.600-609
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• 1998

The experimental investigation of thermal response characteristics by the air flow through the porous media has been carried out. The packed spheres of steel or glass were considered as the porous media in the present study. Temperature distributions of the fluid in the porous media as well as pressure drops through the porous media were measured. The transient temperature variations in the porous media are compared favorably with the analytical results in the high Reynolds number ranges. However, in the low Reynolds number ranges, the experimental data deviate from the analytical results, due to the dominant heat conduction penetration to the upstream direction, which is not considered in the analytical model. The cool-down response of porous media is found to be dependent upon the specific dimensionless time considering the material property and air velocity. The heat discharge process is recommended to be operated until a certain time, considering the cost efficiency.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.170-177
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• 2001

Since plug type passenger door has two motion modes, power transmission unit must be capable of plug-in or plug-out, and sliding mode. Complex planetary gear train is proposed, which is composed of two 2K-H, I type planetary gear units. For the proposed complex planetary gear train, ranges of addendum modification coefficients which would not lead to interferences is analyzed, and optimal addendum modification coefficients among these ranges which generate the maximum efficiency are presented. Based on the interference, efficiency and torque ratio analysis results, complex planetary new train is designed and manufactured.

• 한국지진공학회논문집
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• 제16권6호
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• pp.29-36
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• 2012

Involved in a research for the application of seismic isolation to the nuclear industry, this study evaluates firstly the responses of seismic isolation system considering general ranges of structural period and damping ratio by using preliminary design formula. Secondly, coupling effects of input motions were evaluated to find out appropriate conditions of excitations and effect of the iteration for calculating yield displacement of lead core was also assessed in terms of response of a seismically isolated structure. Finally, the results of preliminary design calculation were compared with those of dynamic analysis and the propriety of the formula was evaluated and appropriate ranges of reduction factor were also suggested from the results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.30-31
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• 2006

To improve the mean-life and the reliability of power cable, we have investigated specific heat (Cp). Specific-heat measurement temperature ranges of XLPE insulator were from $20[^{\circ}C]$ to $90[^{\circ}C]$, and the heating rate was $1[^{\circ}C/min]$. In case of semiconducting materials, the measurement temperature ranges of specific heat were from $20[^{\circ}C]$ to $60[^{\circ}C]$ and the heating rate was $1[^{\circ}C/min]$. From these experimental results, both specific heat were increased by heating rate because volume of materials was expanded according to rise in temperature. We could know that a small amount of CNT has a excellent thermal properties.

• 한국기계가공학회지
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• 제13권6호
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• pp.15-22
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• 2014

With a conventional positioning apparatus, it is very difficult simultaneously to achieve desired driving ranges and precision levels at the sub-micrometer level. Generally, a lead screw and friction drive have been used as servo control systems. These have large driving ranges, and high-speed positioning is feasible. In this study, we present a global servo system controlled by a laser interferometer acting as a displacement measurement sensor for achieving positioning accuracy at the sub-micrometer level.

• 한국공작기계학회논문집
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• 제10권6호
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• pp.36-41
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• 2001

This article presents a new acceleration/deceleration method for real-time control of autonomous mobile robots. In this method, a function which produces the table of acceleration/deceleration in real-time is proposed. This function, while sat- isfying the basic concept of mechanics, can choose both various ranges of velocity and distance ranges for the selected velocities. Moreover it can control motors in real time. This function is convenient to be realized by programming. In addi- tion, it is faster than other functions because it can be written by assembly language.

• 설비공학논문집
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• 제22권8호
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• pp.523-529
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• 2010

We investigate two-dimensional laminar flow around rectangular cylinders placed in a uniform stream. Numerical simulations are performed, using finite volume method, in the ranges of $50{\leq}Re{\leq}150$ and $0.1{\leq}W/H{\leq}1.0$, where Re and W/H are the Reynolds number and the width-to-height ratio, respectively. The immersed boundary method is used to handle the rectangular cylinder in a rectangular grid system. Comparisons with the previous results show good agreement in Strouhal number, drag and lift coefficient. The present study reports the detailed information of flow structure at different width-to-height ratios in the ranges of $50{\leq}Re{\leq}150$.