• Structural Engineering and Mechanics
• /
• v.91 no.6
• /
• pp.591-606
• /
• 2024

This article proposes a new methodology for identifying beam damage based on changes in modal parameters using the Double Stage Extended Improved Particle Swarm Optimization (DSEIPSO) technique. A finite element code is first developed in MATLAB to model an ideal beam structure based on classical beam theory. An experimental study is then performed on a laboratory-scale beam, and the modal parameters are extracted. An improved version of the PSO algorithm is employed to update the finite element model based on the experimental measurements, representing the real structure and forming the baseline model for all further damage detection. Subsequently, structural damages are introduced in the experimental beam. The DSEIPSO algorithm is then utilized to optimize the objective function, formulated using the obtained mode shapes and the natural frequencies from the damaged and undamaged beams to identify the exact location and extent of the damage. Experimentally obtained resultsfrom a simple cantilever beam are used to validate the effectiveness of the proposed method. The illustrated results show the effectiveness of the proposed method for structural damage detection in the SHM field.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.1A
• /
• pp.58-65
• /
• 2002

This paper deals with a delay problem in the endpoint detection of double-talk detection algorithm using correlation coefficient in the acoustic echo canceller. In case that past power is much bigger than current power like at the end of double-talking period, the power, estimated using forgetting factor, decreases slowly to cause a delay problem in the endpoint detection. In this paper, two methods are proposed to solve this problem. One is that the current power is periodically replaced by a new average power and the other is that the past power in recursive equation is periodically removed or replaced by other values. The simulation results show that proposed methods outperform conventional method in the endpoint of double-talking periods without increasing the computational burden much more.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.2
• /
• pp.662-675
• /
• 2018

Compression history detection plays an important role in digital multimedia forensics. Most existing works, however, mainly focus on digital image and video. Additionally, the existed audio compression detection algorithms aim to detect the trace of double compression. In real forgery scenario, multiple compression is more likely to happen. In this paper, we proposed a detection algorithm to reveal the compression history for MP3 audio. The statistics of the scale factor and Huffman table index which are the parameters of MP3 codec have been extracted as the detecting features. The experimental results have shown that the proposed method can effectively identify whether the testing audio has been previously treated with single/double/triple compression.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.12 no.4
• /
• pp.418-425
• /
• 2012

In this paper, efficient implementation of error correction code (ECC) processing circuits based on single error correction and double error detection (SEC-DED) code with check bit pre-computation is proposed for memories. During the write operation of memory, check bit pre-computation eliminates the overall bits computation required to detect a double error, thereby reducing the complexity of the ECC processing circuits. In order to implement the ECC processing circuits using the check bit pre-computation more efficiently, the proper SEC-DED codes are proposed. The H-matrix of the proposed SEC-DED code is the same as that of the odd-weight-column code during the write operation and is designed by replacing 0's with 1's at the last row of the H-matrix of the odd-weight-column code during the read operation. When compared with a conventional implementation utilizing the odd-weight- column code, the implementation based on the proposed SEC-DED code with check bit pre-computation achieves reductions in the number of gates, latency, and power consumption of the ECC processing circuits by up to 9.3%, 18.4%, and 14.1% for 64 data bits in a word.

• The Journal of the Acoustical Society of Korea
• /
• v.31 no.3
• /
• pp.161-169
• /
• 2012

This paper presents a robust speech end-point detector using double talk detection in echoic conditioned speech recognition robot. The proposed method consists of combining conventional end-point detector result and double talk detector result. We have tested the proposed method in isolated word recognition system under echoic conditioned environment. As a result, the proposed algorithm shows superior performance of 30 % to the available techniques in the points of speech recognition rates.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.55 no.1
• /
• pp.7-12
• /
• 2006

This paper proposes the new voltage event detection method using the weight factor of neural network and describes control system design for the DVR(Dynamic Voltage Restorer) consisted of a rectifier and series inverter applied to 22.9kV distribution system. As this method can express the fault level of each phase, we expect the proposed method can make up for disadvantage of synchronous detection method. Also, in this paper, the control system was designed using double deadbeat controller, As it has an inner current control loop and an outer voltage control loop, we can easily limit the current level during the transient intervals by using the current control loop. Simulation and experiment are performed to prove the analysis of the voltage event detection method and double deadbeat controller.

• Proceedings of the IEEK Conference
• /
• 2000.09a
• /
• pp.233-236
• /
• 2000

In this paper, we consider a code acquisition of W-CDMA signals over multipath Rayleigh fading channel when double-dwell serial search code acquisition is used for initial synchronization. We derive the detection and false alarm probability, and mean acquisition time mathematically by taking into account of multiple H$_1$ cells and double-dwell serial search. It is noteworthy that the more the number of the post-detection integration, the shorter the mean acquisition time in low SNR.

• Journal of Magnetics
• /
• v.13 no.3
• /
• pp.81-84
• /
• 2008

Spin injection and detection in lateral spin valves with double nonmagnetic bottom electrodes are investigated theoretically. Spin-polarized current injected from a magnetic electrode is split to two bottom electrodes, and nonlocal spin signals between the other magnetic electrode and the nonmagnetic electrodes are calculated from drift-diffusion equations. It is shown that the spin signal is approximately proportional to the associated current in the electrode.

• Journal of Broadcast Engineering
• /
• v.5 no.1
• /
• pp.123-129
• /
• 2000

This paper addresses a new double detection algorithm which is based on the fuzzy control in the adaptive echo canceller of communication system. In this method, the two input of the fuzzy inference for detecting double talk condition are used. The one is the cross-correlation coefficient between the error signal and the primary signal which is the summed signal of the real echo signal and the near-end signal. The other is the cross-correlation coefficient between the estimation error signal and the primary signal. The fuzzy controller made a fuzzification for two inputs by the membership functions of trapezoid and them became the composition using inference rules. The composed result is defuzzificated by the center gravity method. The output is compared with two threshold values to detect double talk and echo path variation effectively. It is confirmed by computer simulation that this fuzzy double talk detector is able to track echo path variation accurately.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.42 no.1
• /
• pp.65-70
• /
• 2005

This paper deals with the problem of double-talk (DT) detection in anacoustic echo canceller (AEC). In the DT detection algorithm with correlation coefficient, detection errors occasionally occur because it is hard to set the threshold to distinguish DT from echo path change (EPC). Adaptive filter falls into the situation that it stops updating its filter coefficients when EPC is erroneously considered as DT at the starting-point of EPC. In addition, in case of echo path changing during the DT period, the end-point detection of DT period fails so that the AEC cannot update its filter coefficients for a while even after the DT period ends. To solve these problems, in this paper, we propose a novel AEC that employs an auxiliary filter. We use the idea that though the error signal cannot be estimated using reference signal in case or DT situation but it can be in case or EPC situation. The experimental result verifies that the proposed method could solve the problems caused by DT detection error or echo path change during the DT period.