• Journal of Advanced Marine Engineering and Technology
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• 제40권8호
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• pp.726-732
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• 2016

Clustering analysis is widely used in data mining to classify data into categories on the basis of their similarity. Through the decades, many clustering techniques have been developed, including hierarchical and non-hierarchical algorithms. In gene profiling problems, because of the large number of genes and the complexity of biological networks, dimensionality reduction techniques are critical exploratory tools for clustering analysis of gene expression data. Recently, clustering analysis of applying dimensionality reduction techniques was also proposed. PCA (principal component analysis) is a popular methd of dimensionality reduction techniques for clustering problems. However, previous studies analyzed the performance of PCA for only full data sets. In this paper, to specifically and robustly evaluate the performance of PCA for clustering analysis, we exploit an improved FCBF (fast correlation-based filter) of feature selection methods for supervised clustering data sets, and employ two well-known clustering algorithms: k-means and k-medoids. Computational results from supervised data sets show that the performance of PCA is very poor for large-scale features.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1534-1539
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• 2021

This study reports on the dissolution behavior of SrO in LiCl at varying SrO concentrations from low concentrations to excess. The amount of SrO dissolved in the molten salt and the species present upon cooling were determined. The thermal behavior of LiCl containing various concentrations of SrO was investigated. The experimental results were compared with results from the simulated results using the HSC Chemistry software package. Although the reaction of SrO with LiCl in the standard state at 650 ℃ has a slightly positive Gibbs free energy, SrO was found to be highly soluble in LiCl. Experimentally determined SrO concentrations were found to be considerably higher than those present in used nuclear fuel (<2 g/kg). As Sr-90 is one of the most important heat-generating nuclides in used nuclear fuel, this finding will be impactful in the development of fast, simple, and proliferation-resistant heat reduction processes for used nuclear fuel without the need for separating nuclear materials. Heat reduction is important as it decreases both the volume necessary for final disposal and the worker handling risk.

• Smart Structures and Systems
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• 제29권3호
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• pp.475-484
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• 2022

The loss of cable tension for civil infrastructure reduces structural bearing capacity and causes harmful deformation of structures. Currently, most of the structural health monitoring (SHM) approaches for cables rely on contact transducers. This paper proposes a cable tension identification technology using percussion sound, which provides a fast determination of steel cable tension without physical contact between cables and sensors. Notably, inspired by the concept of tensioning strings for piano tuning, this proposed technology predicts cable tension value by deep learning assisted classification of "percussion" sound from tapping a steel cable. To simulate the non-linear mapping of human ears to sound and to better quantify the minor changes in the high-frequency bands of the sound spectrum generated by percussions, Mel-frequency cepstral coefficients (MFCCs) were extracted as acoustic features to train the deep learning network. A convolutional neural network (CNN) with four convolutional layers and two global pooling layers was employed to identify the cable tension in a certain designed range. Moreover, theoretical and finite element methods (FEM) were conducted to prove the feasibility of the proposed technology. Finally, the identification performance of the proposed technology was experimentally investigated. Overall, results show that the proposed percussion-based technology has great potentials for estimating cable tension for in-situ structural safety assessment.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(4)
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• pp.199-202
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• 2000

Speaking Rate has variety depends on the situation and habit of speakers. It has been many studied about speaking rate In speaker recognition. The study of speaking rate in speech recognition is one of considerable matter when It is recognized the speakers and it is measured by many speech data base and complicate estimation for accuracy. In this paper, conventional vocoder process the speech signal when encoding and transmitting without regard to speaking rate so in order to apply the speaking rate for vocoder It should be considered the simpler algorithm and less computation amount than the conventional method of speaking rate used In speech recognition. We proposed the speaking rate algorithm which is used the simple parameter with Line Spectrum Pair (LSP). The proposed peaking rate method is measured by the information of LSP in speech. We measured the variety rate of phenomenon about utterances which have different velocity, respectively. As a result, It has distinct variation rate of phenomenon between utterances uttered fast and slow and the rate is 42.8% higher in case of uttered fast than in case of uttered slow.

• 전기학회논문지
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• 제56권6호
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• pp.1047-1054
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• 2007

This paper presents a high efficiency direct instantaneous torque control (DITC) of Switched Reluctance Motor(SRM) based on the nonlinear model. The DITC method can reduce the high inherent torque ripple of SRM drive system, but drive efficiency is somewhat low due to the high current and switching loss during commutations. In order to reduce a torque ripple, a fast torque reference trajectory is selected at every instantaneous rotor position. Based on the nonlinear model of SRM, the developing torque by one phase is fixed and the other phase is regulated for minimum switchings of phase switch and variation of torque. The switching during commutation can be reduced and fast commutation can be obtained in the proposed method. As a result, drive efficiency could be improved as well as torque ripple reduction. The validity of proposed method is verified by computer simulations and comparative experiments.

• 대한음성학회지:말소리
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• 제55권
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• pp.93-102
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• 2005

In this paper, sub-stream based eigenvoice method is proposed to overcome the weak points of conventional eigenvoice and dimensional eigenvoice. In the proposed method, sub-streams are automatically constructed by the statistical clustering analysis that uses the correlation information between dimensions. To obtain the reliable distance matrix from covariance matrix for dividing into optimal sub-streams, MAP adaptation technique is employed to the covariance matrix of training data and the sample covariance of adaptation data. According to our experiments, the proposed method shows $41\%$ error rate reduction when the number of adaptation data is 50.

• Journal of Information Technology Applications and Management
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• 제22권3호
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• pp.105-114
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• 2015

This paper presents a fast Time Difference of Arrival (TDOA) estimation for sound source localization. TDOA is the time difference between the arrival times of a signal at two sensors. We propose a partial cross correlation method to increase the speed of TDOA estimation for sound source localization. We do this by predicting which part of the cross correlation function contains the required TDOA value with the help of the signal energies, and then we compute the cross correlation function in that direction only. Experiments show approximately 50% reduction in the cross correlation computation time thereby increasing the speed of TDOA computation. This makes it very relevant for real world surveillance.

• 소음진동
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• 제9권4호
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• pp.714-719
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• 1999

Because the residual vibration of a gun barrel acts negatively on the firing of a large calibers gun, the fast stabilization of theresidual vibration is indispensible to the precise and successive firing. In this study, the residual vibrations of a gun barrel carrying a bore evacuator and a muzzle brake are investigated by the experimental method. The influence of the eigenfrequencies and the mode shapes of gun barrel on the fast stabilization of the residual vibration is studied for the various masses of bore evacuator and muzzle brake, the possition of bore evacutor. Also the relationships between the funcamental frequencies and the settling times of the gun barrel are investigated for the various parameters. The experiments to reduce the residual vibration using the viscoelastic damping treatment gives the best result among the various treatments for the reduction of residual vibration of the system.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권1호
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• pp.101-109
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• 2017

This paper presents a high-throughput low-complexity 512-point eight-parallel mixed-radix multipath delay feedback (MDF) fast Fourier transform (FFT) processor architecture for orthogonal frequency division multiplexing (OFDM) applications. To decrease the number of twiddle factor (TF) multiplications, a mixed-radix $2^4/2^3$ FFT algorithm is adopted. Moreover, a dual-path shared canonical signed digit (CSD) complex constant multiplier using a multi-layer scheme is proposed for reducing the hardware complexity of the TF multiplication. The proposed FFT processor is implemented using TSMC 90-nm CMOS technology. The synthesis results demonstrate that the proposed FFT processor can lead to a 16% reduction in hardware complexity and higher throughput compared to conventional architectures.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.423-426
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• 2002

New driving waveform which can be inferred by analyzing fundamental LC mechanism is suggested. The main idea of the new waveform is the stabilizing LC layer fast in the cell by controlling the middle director of LC layer. Consequently, we can get not only numerical reduction of optical response merely but also the change of dynamic transmittance from applied voltage exactly