• Journal of Drive and Control
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• v.11 no.3
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• pp.47-54
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• 2014

Clutches are an integral part of the automatic transmission for changing gears. Modern automatic transmissions make extensive use of wet multiple-disc clutches employing hydraulic actuation mechanism with electronic control. Although nowadays, highly advanced shifting algorithm implements the superior shift quality and transmission efficiency, its performance should be based on smooth, reliable engagement with a reasonably durable friction material as well as stable clutch piston dynamics. Particularly, clutch filling control is the crucial part of shifting process because only the open-loop control is available due to the lack of measurement. In this paper, the effect of clutch-fill control parameters on clutch piston dynamics is experimentally investigated by using clutch piston test equipment which enables the clutch piston to actuate similar to real shifting conditions. The experimental analysis results can be expected to be utilized for the calibration of proportional solenoid valve as reference current profile data in vehicle test.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.5
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• pp.495-500
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• 1994

Mackerel water-soluble protein solution Mackerel meat washing water were concentrated by isoelectric point shifting precipitation process, and the concentrates were utilized as a material for processing of an elastic gel food such as kamaboko. The water-soluble proteins were partly polymerized during the isoelectric point shifting precipitation process. Then, the water soluble protein concentrates were partly substituted for frozen minced Alaska pollack meat in processing of a good quality kamaboko. The maximum substitution percentage for good quality kamaboko manufacturing was concluded to be below $30\%$, according to the criteria of color difference, jelly strength and folding tests using the substituted recovered protein concentrates.

• Journal of Electrical Engineering and Technology
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• v.13 no.3
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• pp.1294-1303
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• 2018

This study optimises the no-load voltage waveform of tubular hydro-generators by a simple design scheme. For different centerlines of the pole shoe and damper bar, the optimisation effects on the no-load voltage waveform are investigated in two tubular hydro-generators with different weighted powers (34 MW and 18 MW). The results are compared with those of the traditional stator-slots skewed design. The quality of the no-load voltage waveform was related to the shifting degree, and the different optimisation effects between the integer slot generator (q = 2) and the fractional slot generator (q = 11/2) were analysed. This research can improve the quality of the power output and no-load voltage waveform, and provide an effective reference for improving the industrial design and manufacture level of tubular hydro-generators.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.4
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• pp.10-15
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• 2007

Taguchi methods have been used for a long time to improve the product quality and process performance of a manufacturing system, Few researchers have applied this methodology in laser beam cutting (LBC) of sheet metals and found the considerable improvement in cut qualities. In all experimental investigations of LBC so far, the objective was to optimize the single quality characteristic at a time. In this paper the simultaneous optimization of multiple quality characteristics such as Kerf width and material removal rate (MRR) during pulsed Nd:YAG LBC of thin sheet of magnetic material (high Silicon-steel) has been presented using Taguchi's quality loss function. The results show the considerable improvement in multiple S/N ratio as compared to initial cutting condition. Also, the comparison of results from single and multi-objective optimization have been presented and it was found that the loss in quality is always possible shifting from single quality to multiple quality optimization.

• MALSORI
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• no.45
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• pp.63-77
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• 2003

The purpose of voice color conversion is to change the speaker identity perceived from the speech signal. In this paper, we propose a new voice color conversion algorithm through the formant shifting and the spectrum-tilt modification in the frequency domain. The basic idea of this technique is to convert the positions of source formants into those of target speaker's formants through interpolation and decimation and to modify the spectrum-tilt by utilizing the information of both speakers' spectrum envelops. The LPC spectrum is adopted to evaluate the position of formant and the information of spectrum-tilt. Our algorithm enables us to convert the speaker identity rather successfully while maintaining good speech quality, since it modifies speech waveforms directly in the frequency domain.

• The Journal of the Acoustical Society of Korea
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• v.27 no.3E
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• pp.84-94
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• 2008

Displacement estimation is a crucial step in ultrasonic strain imaging. The displacement between a pre- and postcompression signal in the current data window is estimated by first shifting the postcompression signal by the displacement obtained in the previous data window to reduce their decorrelation and then determining the remaining part of the displacement through autocorrelation and conversion of phase difference into time delay. However, since strain image quality tends to vary with the amount of compression applied, we propose two new methods for enhancing strain image quality, i.e., displacement normalization and adaptive persistence. Both in vitro and in vivo experiments are carried out to acquire ultrasound data and produce strain images in real time under the application of quasi static compression. The experimental results demonstrate that the methods are quite effective in improving strain image quality and thus can be applied to implementing an ultrasound elasticity imaging system that operates in real time.

• Journal of KIISE:Software and Applications
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• v.37 no.6
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• pp.417-429
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• 2010

Reversible watermarking inserts watermark into digital media in such a way that visual transparency is preserved and then enables to restore the original media from the marked one without any loss of media quality. This watermarking can be applied to quality-sensitive imaging such as medical imaging, military imaging, remote-sensing imaging, and precious artwork, where the original media should be preserved during image processing and analysis. In this paper, a reversible image watermarking technique that embeds message bits by modifying the differential histogram of adjacent pixels is presented. In order to satisfy both high embedding capacity and visual quality, the proposed technique exploits the fact that adjacent pixels in the image have highly spatial correlation. Also, we prevent overflow/underflow problem and salt-and-pepper artifacts by employing a predicted error compensation scheme. Through experiments using various test images, we prove that the presented technique provides perfect reversibility and high embedding capacity, while maintaining the induced-distortion low.

• International Journal of Contents
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• v.14 no.4
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• pp.18-23
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• 2018

Recently, the developments in IT technology and the spread of smart phones have made Fin-Tech, which is a combination of financial services and IT technology, a big issue. In accordance with the growth trend of mobile payments in the world, all financial transactions in Korea are gradually shifting to smart phones. In fact, mobile payment system services are not widely used by users. In particular, the risk factors involved when users want to use the service are one of the factors that hinder the expansion of the usage of mobile financial payment service. The risk factors affect the trust of the mobile payment system users. Therefore, this study investigates the risk factors of the mobile payment system and the manner in which it affects a user's trust. We have also examined as how user's trust affects trust in the quality of the mobile payment system. To this end, the trust in overall quality of use was largely divided into trust in system quality, trust in information quality, and trust in service quality. Perceived finance risk, perceived performance risk, and perceived privacy risk have negative effects on cognitive trust. However, perceived time risk did not affect cognitive trust. User's cognitive trust also has an effect on trust in quality.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.02a
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• pp.251-256
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• 2003

트랙터는 작업 시 부하의 변동이 크고, 부하 변동에 따른 적합한 단수로 운전 작업이 요구되기 때문에 잦은 변속이 요구된다. 특히 유단 변속의 경우 변속 시 큰 부하의 변동과 부적절한 변속 단수 설정할 때 변속 충격이 발생할 수 있다 이러한 변속 충격은 작업 효율을 저하시킬 뿐 아니라 운전자의 승차 감을 저하시킨다. (중략)

• Proceedings of the Korean Society of Crop Science Conference
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• 2023.04a
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• pp.42-42
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• 2023