• Korean Journal of Metals and Materials
• /
• v.49 no.12
• /
• pp.930-936
• /
• 2011

In the present study, we show that the addition of Ag, an element having a positive enthalpy of mixing with Cu in the liquid state, enables the simultaneous enhancement of the glass forming ability and the plasticity in Cu-Zr-Ag bulk metallic glasses (BMGs). Rods of 4 mm diameter could be prepared with a fully amorphous structure and values of plastic strain up to 18% were measured under a compression mode for compositions around $Cu_{42.5}Zr_{47.5}Ag_{10}$. The possible role of Ag in the change of the atomic structure and the enhancement of the plastic strain in the ternary Cu-Zr-Ag BMGs is discussed based on analyses from transmission electron microscopy and EXAFS (extended X-ray absorption fine structure).

• Journal of the Optical Society of Korea
• /
• v.20 no.3
• /
• pp.401-406
• /
• 2016

This study first proposes a new version of a photonic crystal based de-multiplexer operating under the slow light regime, secondly analyses the structure numerically to demonstrate de-multiplexing operation and finally studies the impact of light speed on the performance of the proposed structure. The operation wavelength is 1.55 µm. The study indicates that, by adjusting the speed of light, around 0.1C, in the main waveguide and in the output channels’ waveguides, an enhancement in the performance of the de-multiplexer will be gained.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2007.05a
• /
• pp.261.1-261.1
• /
• 2007

• Proceedings of the Korean Magnestics Society Conference
• /
• 1993.03a
• /
• pp.94-95
• /
• 1993

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.38 no.5
• /
• pp.380-387
• /
• 1989

The Conventional-Anti-reset-Windup (CAW) structure gives pretty good performance among the conventional strategies that prevent systems from saturation, but there is no systematic way of designing the control systems. Also, it frequently destabilizes the systems. Moreover, the CAW structure cannot be applied when the output of the saturating actuator cannot be measured. Therefore the CAW structure is modified to accommodate this situation. An effective designing method is proposed to give better performance of the control system. The stability of the control system is also considered. The usefulness of the proposed method is shown by applying this method to a few examples.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.38 no.4
• /
• pp.353-361
• /
• 2001

A new stereoscopic codec. structure using MPEG-2 multiview profile is presented in this paper. In the suggested codec., the left image is coded with motion estimation in the base layer and the right image is coded with disparity estimation in the enhancement layer. Since it is possible to calculate rough motion of the right image sequence with disparity and motion of the left image sequence, motion compensation of the enhancement layer is performed without motion estimation. To apply this mathod to MVP codec., the prediction mode of base layer and enhancement layer is restricted, and B picture mode in the base layer is removed. Since the proposed codec. does not perform motion estimation in the enhancement layer encoding and prediction mode of base layer is restricted, it's structure is simple and reduces the encoding time. We compared the SNR of encoded image with three different structured codec., and the experimental results show suggested codec. have comparable result.

• The Journal of the Acoustical Society of Korea
• /
• v.41 no.1
• /
• pp.30-37
• /
• 2022

This paper compares and evaluates model performance from two perspectives according to the learning target and network structure for training Deep Neural Network (DNN)-based speech enhancement models in the frequency domain. In this case, spectrum mapping and Time-Frequency (T-F) masking techniques were used as learning targets, and a real network and a complex network were used for the network structure. The performance of the speech enhancement model was evaluated through two objective evaluation metrics: Perceptual Evaluation of Speech Quality (PESQ) and Short-Time Objective Intelligibility (STOI) depending on the scale of the dataset. Test results show the appropriate size of the training data differs depending on the type of networks and the type of dataset. In addition, they show that, in some cases, using a real network may be a more realistic solution if the number of total parameters is considered because the real network shows relatively higher performance than the complex network depending on the size of the data and the learning target.

• Transactions on Control, Automation and Systems Engineering
• /
• v.2 no.1
• /
• pp.7-12
• /
• 2000

A new speech enhancement algorithm for speech corrupted by slowly varying additive colored noise is suggested based on a state-space signal model. Due to the FIR structure and the unimportance of long-term past information, the receding horizon (RH) FIR filter known to be a best linear unbiased estimation (BLUE) filter is utilized in order to obtain noise-suppressed speech signal. As a special case of the colored noise problem, the suggested approach is generalized to perform the single blind signal separation of two speech signals. It is shown that the exact speech signal is obtained when an incoming speech signal is noise-free.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.8 no.6
• /
• pp.153-157
• /
• 2008

Recently, electronic devices is produced by multilayer structure, therefore analysis for hidden layers is important nondestructive inspection. This paper presents visibility enhancement methods for the ultrasonic multiple echoes reflected from adhesive layer in the multilayers using digital signal processing. The reflected signals from the multilayers come out interval of the peaks in the power cepstrum. In the experiment, the adhesive layers of settled thickness using epoxy were formed. The reflected signals from the multilayer is detected by pulse-echo method and power cepstrum is processed for enhancement of visibility.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.143-146
• /
• 1998

A new stereoscopic codec. structure using MPEG-2 multiview profile is presented in this paper. In the suggested codec., the left image is coded with motion estimation in the base layerand the right image is coded with disparity estimation in the enhancement layer. Since it is possible to calculate rough motion of the right image sequence with disparity and motion of the left image sequence, motion compensation of the enhancement layer is performed without motion estimation. Since the proposed codec. does not perform motion estimation in the enhancement layer encoding, it is simple and reduces the encoding time. We compared the PSNR of encoded image with three different structured codec., and the experimental results show that suggested codec. has comparable with other codecs.