• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.330-335
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• 2001

Characteristics of the present world market include demanding and sophisticated customers, requirement of high quality and innovative products, greater product diversity, increasing labour and products costs, availability of diverse alternatives to the customers and smaller batch sizes to satisfy a variety of customer profiles. To fulfil these characteristics, manufacturing companies need to be flexible adaptable, proactive and able to produce variety of products in short time at low cost. The aim of the study is to develop a computer-aided design system for water-gate on AutoCAD R2000 system. The developed system has been written in AutoCAD and VisualLISP with a personal computer, and is composed four modules which are the gate-lifter input module, guide-frame input module, and upgrade module. Based on knowledge-based rules, the system is designed by considering several factors, such as width and height of a water-gate, material, object of product and maximum depth of water.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.535-539
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• 2001

The aim of this paper presents to develop a computer-aided design system for water gate on AutoCAD R2000system. The developed system has been written in AutoCAD and Visua ILISP with a personal computer, and is composed four modules which are the gate-lifter input module, guide-frame input module, template input module and upgrade module. Based on knowledge-based rules, the system is designed by considering several factors, such as width and height of a water gate, material, object of product and maximum depth of water. Employing the developed system enable the designer and manufactures of water gate to be more efficient in this field, and its potential capability for enhancement included FEM(Finite Element Method) and quotation system.

• Journal of KSNVE
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• v.10 no.4
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• pp.642-647
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• 2000

Conventional cepstrum has been widely used to detect echo and fault signals embedded in noise. One of the problems of finding impulse signals using the conventional cepstrum in that it is normally very sensitive to signal to noise ratio (SNR). This paper proposes a signal processing method to detect impulse signal in noisy environment. Because the proposed method minimizes the variance of signal power at a cepstrum domain, it is suggested to be called as minimum variance cepstrum (MV cepstrum). Computer simulations have been performed to understand the characteristics of the MV cepstrum. Both mathematical approach and computer simulations confirmed that the MV cepstrum is a useful technique to detect impulse in noisy environment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.68-73
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• 1995

반사음이 포함된 신호의 계측을 통하여 원음의 크기와 반사계수의 크기, 지연시간 등의 추출을 수치적 예를 사용하여 규명해 보았다. 반사계수의 측정시, 폐쇄된 음장에서는 정상파비로 표시되는 단일 주파수 신호를 사용하는 것이 실제 계측시 가장 손쉬운 방법이며, 광역의 주파수 성분에 걸쳐 그 값을 파악할 필요가 있는 경우에는 켑스트럼 상에서 반사파의 효과가 원음과 확연히 구분되는 신호를 사용하는 것이 신호처리 과정에서 불필요한 부담을 제거시켜 준다. 개방 음장에서는 반사파가 1개 밖에 포함되지 않으므로 이 경우에는 PSD 상의데이터 처리를 통하든지 또는 캡스트럼의 재편집을 통하여 원음의 크기와 성분 그리고 반사계수 등을 손쉽게 추출해 낼 수 있다. 광대역 주파수 성분을 가진 음원을 계측에 사용할 경우에는 comb lifter의 적용에 보다 세심한 주의를 기울일 필요가 있으며 켑스트럼 상의 추가 충격응답함수의 식별에 보다 더 합리적인 방법이 강구되어야 할 것이다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.87-92
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• 1999

The biggest challenge facing today manufacturing industry is better quality and high productivity. From an economic point of view, productivity is the most important parameter, as high productivity will reduce the cost. However, the customers of today are not only cost concerned, but also quality conscious. So high accuracy levels should also be achieved in the manufacturing process. This paper reports the development of a automatic design system based on AutoCAD program. This work is composed of three section that are design of top down menu, guide frame and gate lifter for water-gate programed by AutoLISP language and runned Windows system. The developed system ultimately generates the design for a water gate through AutoCAD program. In the design of the water gate, it needs about 23 hours with an expert, but this system can be only 80 seconds without an expert.

• Proceedings of the ESK Conference
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• 1997.10a
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• pp.168-176
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• 1997

The purpose of this study is to know load for each human body's knee joint to endure load efficiently, when weight lifter pulls suitable bar in the each weight lifting level. To use the difference of load and correlation between men and women, the conclusion of this stduy is to find parameters to conduct maximum limitation of maximum load to search maximum limitation. The moment of each joint in the lower area was to have a much difference between group of the turunk in the first step. It decreased rapidly until decent and greatly pulled in the second step. Neuromusclar moment increased suddenly in the decrease phase. This phenomenon resulted from shock-absorbing function to sbsorb a load from bar.

• Speech Sciences
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• v.10 no.4
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• pp.137-147
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• 2003

Speech synthesis can classify by synthesis way, that is waveform coding, source coding and mixture coding. Specially, waveform coding is suitable for high quality synthesis. However, it is not desirable by synthesis techniques of syllable or phoneme unit because it do not separate and handles excitation and formant part. Therefore, there is a need for pitch alteration method applied in synthesis by the rule in waveform coding. This study propose about pitch alteration method that use spectrum scaling after do to flatten spectra by subband linear approximation to minimize spectrum distortion. This paper show evaluation whether show excellency of some measure compared with LPC, Cepstrum, lifter function and method that propose. estimation method seeks distribution of each flattened signal and measured degree of flattened spectra Signal flattened is normalized, So that highest point amounts to zero, and distribution of signal ,whose average is zero, is calculated. this show result that measure the spectrum distortion rate to estimate performance of method that propose. The average spectrum distortion rate was kept below the average 2.12%, so the method that propose is superiors than existent method.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.242-255
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• 1999

In order to manufacture high quality goods, the engineers who will design them has to have board technical experience as well as profound engineering knowledge. The engineers also be able to design and manufacture well development goods base on new advanced technology. Design process can be defined as transforming activity raw material into finished producted for human needs. The wealth of nation depend on its ability to retrieve natural resources and manufacture goods. Its ability, creation of goods, is most fundamental component of economic wealth of rich country. The rich countries have combine their own design knowledge with computer technology and create new effective design process. In this paper, one of the useful and practice design process created for railway industry is introduced. Base on the concept of this design process, the automatic wheelchair lifter design for railway vehicle is performed.

• The Journal of the Acoustical Society of Korea
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• v.16 no.4
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• pp.57-63
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• 1997

In this paper, we study the efficient feature vector extraction method and front-end processing to improve the performance of the speech recognition system using KT(Korea Telecommunication) database collected through various telephone channels. First of all, we compare the recognition performances of the feature vectors known to be robust to noise and environmental variation and verify the performance enhancement of the recognition system using weighted cepstral distance measure methods. The experiment result shows that the recognition rate is increasedby using both PLP(Perceptual Linear Prediction) and MFCC(Mel Frequency Cepstral Coefficient) in comparison with LPC cepstrum used in KT recognition system. In cepstral distance measure, the weighted cepstral distance measure functions such as RPS(Root Power Sums) and BPL(Band-Pass Lifter) help the recognition enhancement. The application of the spectral subtraction method decrease the recognition rate because of the effect of distortion. However, RASTA(RelAtive SpecTrAl) processing, CMS(Cepstral Mean Subtraction) and SBR(Signal Bias Removal) enhance the recognition performance. Especially, the CMS method is simple but shows high recognition enhancement. Finally, the performances of the modified methods for the real-time implementation of CMS are compared and the improved method is suggested to prevent the performance degradation.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.2
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• pp.83-88
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• 2016

In this paper, a design method for a logistics transportation robot based on a modular conveyor rack and path planning considering the environment of a logistics center is proposed. The driving part of the logistics transportation robot is designed and the working method of lifter for the transportation function is explained. The design of the modular conveyor rack is also described and an algorithm for a logistics transportation robot using a modular conveyor rack is suggested. The $A^*$ algorithm is improved by using the concept of rotation cost and the initial state of the transportation robot's characteristics. We experimented with a four-step transportation algorithm for a logistics transportation robot using a modular conveyor rack and showed that the proposed method can be used successfully in a logistics center. In addition, we verified the effectiveness of the improved $A^*$ algorithm considering the rotation cost and the initial state of the robot.