• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.240-243
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• 2005

This study deals with the shape optimization of a wire spacer fuel assembly of Liquid Metal Reactors (LMRs). The Response Surface based optimization Method is used as an optimization technique with the Reynolds-averaged Navier-Stokes analysis of fluid flow and heat transfer using Shear Stress Transport (SST) turbulence model as a turbulence closure. Two design variables namely, pitch to fuel rod diameter ratio and lead length to fuel rod diameter ratio are selected. The objective function is defined as a combination of the heat transfer rate and the inverse of friction loss with a weighting factor. Three level full-factorial method is used to determine the training points. In total, nine experiments have been performed numerically and the resulting datas have been analysed for optimization study. Also, a comparison has been made between the optimized surface and the reference one in this study.

• Neonatal Medicine
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• 제16권2호
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• pp.131-136
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• 2009

Preterm infants are frequently discharged from the hospital with growth retardation. Given the potentially lifelong effects of growth impairmnet during a critical time of development, considerable effort should be focused on improving growth after discharge. Growth monitoring must be based on regular measurements of weight, length, and head circumference to identify those preterm infants with poor growth that may need additional nutritional support. Although prior studies vary in design and the intervention used, the evidence supports the use of fortified formulas in formula-fed preterm infants after discharge. The situation for infants fed human milk is much less clear, it seems prudent to concentrate our efforts on the encouragement of breast-feeding in this population. Catch up growth may have many benefits, and may lead to improved development. However, its long-term metabolic consequences are currently unclear. Understanding the optimal means of providing nutrition after discharge is an ongoing process.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권12호
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• pp.6063-6079
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• 2019

When the length of sampling data sequence is too large, the method of gesture recognition based on traditional Dynamic Time Warping (DTW) algorithm will lead to too long calculation time, and the accuracy of recognition result is not high.Support vector machine (SVM) has some shortcomings in precision, Edit Distance on Real Sequences(EDR) algorithm does not guarantee that noise suppression will not suppress effective data.A new method based on Improved Interpolation Dynamic Time Warping (IIDTW)algorithm is proposed to improve the efficiency of gesture recognition and the accuracy of gesture recognition. The results show that the computational efficiency of IIDTW algorithm is more than twice that of SVM-DTW algorithm, the error acceptance rate is FAR reduced by 0.01%, and the error rejection rate FRR is reduced by 0.5%.Gesture recognition based on IIDTW algorithm can achieve better recognition status. If it is applied to unlock mobile phone, it is expected to become a new generation of unlock mode.

• 음성과학
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• 제2권
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• pp.125-134
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• 1997

Human beings can perceive various aspects of sound including loudness, pitch, length, and timber. Recently many studies were conducted to clarify complex auditory scales of the human ear. This study critically reviews some of these scales (decibel, sone, phon for loudness perception; mel and bark for pitch) and proposes to apply the scales to normalize acoustic correlates of human speech. One of the most important aspects of human auditory perception is the nonlinearity which should be incorporated into the linear speech analysis and synthesis system. Further studies using more sophisticated equipment are desirable to refine these scales, through the analysis of human auditory perception of complex tones or speech. This will lead scientists to develop better speech recognition and synthesis devices.

• 말소리와 음성과학
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• 제1권3호
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• pp.87-93
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• 2009

The purpose of this experimental study is to investigate and compare the vowel lengths of English diphthongs and low vowels among native-English-speaking Americans and Korean college exchange students. To do this eight words and sixteen sentences were uttered and recorded by nine subjects, five Korean subjects and four American subjects. Results showed that the vowel lengths of English low vowels between American subjects and Korean subjects were different, which may lead to foreign accent of Korean speakers. Comparing the average length of English low vowels of Korean subjects with those of American subjects, we can see that American subjects tend to pronounce the English low vowels longer than Korean subjects do. In the pronunciation of diphthongs /eI/ and /ou/, Korean subjects pronounced longer than American subjects did. However, in the pronunciation of diphthongs /au/, /aI/, and /ɔI/, American subjects pronounced longer than Korean subjects did.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1645-1647
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• 1997

Electronic circuits are becoming more vulnerable owing to the development of integrated circuit. Computer and info-communication facilities are very sensitive to surges caused by lightning, and they can suffer a malfunction and damage. Recent concern about damage and upset caused by transient overvoltages has focused on surge protection. The most important parameter in surge protection is the transient grounding impedance. In this paper, the transient grounding impedances of a rod electrode have been measured under impulse current waves. Z-t, Z-i and V-i characteristics of the grounding electrode in according to the length of the grounding lead wire were obtained and analyzed.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.473-478
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• 2004

This work presents the Thermal Hydraulic analysis has been performed for a 19-pin wire-spacer fuel assembly using three-dimensional Reynolds-averaged Navier-Stokes equations. SST model is used as a turbulence closure. The whole fuel assembly has been analyzed for one period of the wire-spacer using periodic boundary condition at inlet and outlet of the calculation domain. The overall results far a preliminary calculation show a good agreement with the experimental observations. It has been found that the major unidirectional flows are the axial velocity in sub-channels and the peripheral sweeping flows and the velocities are found to be following a cyclic path of period equal to the wire-wrap pitch. The temperature is found to be maximum in the central region and also, there exist a radial temperature gradient between the fuel rods. The major advantage of performing this kind of analysis is the prediction of thermal-hydraulic behavior of a fuel assembly with much ease.

• 대한기계학회논문집
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• 제18권12호
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• pp.3202-3218
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• 1994

Mode shapes and natural frequencies of vibrating laminated composite plates are taken using real-time and time-average holographic interferometry. Debonds and delamination in the laminated plates are measured nondestructively. During holographic testing of composite plates, it has been found that the conditions for the local resonance in debonds are strongly dependent on the frequency of excitation. A membrane resonance model was proposed to describe this behavior. Relations between characteristic length according to the size, shape of debonds and membrane resonance frequency are presented. Several experiments were performed to verify the membrane resonance model. The agreements between the predicted excitation frequency and the observed resonance frequency are good. The experimental results show that higher stresses and strains due to local resonance lead to the debond detection.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.983-984
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• 2006

The correct computer simulation of the powder compaction stage requires the determination of the elastoplastic parameters which characterize its mechanical behavour. Instrumented dies are frequently used to monitor the longitudinal and radial stress occurring during powder compaction. When strain gages are employed a previous calibration is needed. Many sources of error exist that can lead to the incorrect calibration of the instrumented die. By means of a FEM simulation some of these problems are analysed. The effect of die wall thickness, compression length, and strain location are studied.

• 대한의용생체공학회:의공학회지
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• 제17권3호
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• pp.379-386
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• 1996

This paper describes an approach for classifying myoelectric patterns using a multilayer perceptrons (MLP's) and hidden Markov models (HMM's) hybrid classifier. The dynamic aspects of EMG are important for tasks such as continuous prosthetic control or vari- ous time length EMG signal recognition, which have not been successfully mastered by the most neural approaches. It is known that the hidden Markov model (HMM) is suitable for modeling temporal patterns. In contrasts the multilayer feedforward networks are suitable for static patterns. Ank a lot of investigators have shown that the HMM's to be an excellent tool for handling the dynamical problems. Considering these facts, we suggest the combination of MLP and HMM algorithms that might lead to further improved EMG recognition systems.