Papers by Keyword: Signal Processing

Abstract: This paper shows the application of discrete wavelet transform in the analysis of ECG signals to detect R-peaks of the QRS complex. The proper analysis of the ECG signal is crucial to reveal the changes in the waveform to detect heart related diseases. The detection of the P-wave, T-wave, QRS complex is important and the wavelet transform offers a good possibility to recognize the abnormalities. Three different wavelets, Symlet, Coiflet and Daubechies are used for the detection and are compared to choose the most efficient one to identify the R-peaks. Multiresolution analysis (MRA) is used to determine the sufficient level of decomposition. MIT-BIH Arrhythmia Database is used as a dataset for the experiment.

Abstract: The fundamental algorithms of many additional applications, including those that deal with machine learning, signal processing, image processing, and video processing, depend heavily on addition units. In addition to their intrinsic value, addenda are essential for many mathematical operations such as division, multiplication, squaring, and comparison. The parallel prefix adder (PPA) is among the fastest adders available. The efficient parallelization implementation of Parallel Prefix Adders (PPAs) in the carry production (G) and propagation (P) phases may be responsible for their fast performance. A PPA approximation based on estimates from POs is presented in this work. Each of these requires less energy than the others. Keywords—Adder, Signal processing, Algorithm, Parallel Prefix Adder,

Abstract: In this study, Fast Fourier Transform (FFT) was used in order to detect bore hole in a structure. FFT is a common method in digital signal processing (DSP) to characterize the frequency emitted by some structure. This method is widely used because of its simplicity. Computational time needed for FFT is relatively lower than another method. The use of FFT to analyze defect in structure is not commonly used since FFT has some weakness for example spatial frequency cannot be extracted to point out the defect location. In this paper, defect was designated as a hole in a strip iron plate with 20 mm in diameter. The strip iron plate was 1 meter long, 38 mm wide and 3 mm thick. This strip iron plate was clamped at one of its ends while the other side is left free. In order to produce vibration signal, impact hammer Bruel Kjaer Type 8202 was used with plastic tip to limit the vibration frequency in to the range of 0 - 1000 Hz. The trigger point was 30 mm from its free end. Three accelerometers were placed series in one line with the trigger point with 300 mm distance of each accelerometer. The position of the hole was varied in three different position. The first position was between trigger point and first accelerometer, between first and second accelerometer and between the second and third accelerometer. The raw signal obtained from the accelerometer was processed by using FFT to understand the mode shape changes in the strip iron plate due to the bore hole. Furthermore, the FFT result was analyzed as function of receiver position to determine the position of hole. The result shows that the frequency characters were different in each case and further analysis by using magnitude-squared coherence function need to be used in order to quantitatively find the difference between FFT result.

Abstract: Paper describes new approach to material structure analysis by means of ultrasound probing. Short-time Fourier transform and time-frequency analysis used to determine structure inhomogeneity present and perform structure condition assessment. Experimental results show possibilities of polymer materials structure assessment.

Abstract: In this paper, a heuristic optimization technique called Harmony Search Algorithm (HSA) is efficiently employed to design Infinite Impulse Response (IIR) Discrete Fractional Order Integrators (DFOIs). Unlike the methods reported in the literature, no discretization (s-to-z transform) operator is necessary to obtain the DFOIs by using the proposed approach. To investigate the design efficiency, the HSA-based DFOIs have been evaluated against the designs based on Real coded Genetic Algorithm (RGA), Particle Swarm Optimization (PSO), and Differential Evolution (DE) using different frequency response error metrics. The reliability in the performance of the proposed DFOIs are extensively investigated by conducting various statistical tests. Comparison of fitness convergence demonstrates that HSA achieves the near global optimal solution in the least number of iterations. Thus, HSA exhibits superior computational efficiency in solving this multimodal optimization problem. The proposed DFOIs also outperform the reported designs.

Abstract: The challenging for buyers around the globe to identify good quality of Durian. For several kinds of Durian, it may be difficult for buyers to determine the Durian quality by appearance. The ability to select only good quality Durian without cutting or cleaving is useful because buyers will not waste money ordering undesirable Durian.This paper proposes a nondestructive technique to determine the stages of maturity of durian fruits. The presented methodology utilizes the concept of pattern matching. We used the local knocking equipment to knock the durian for knocked-sound. After that the knocked-sound was analyzed and generated to Mel-frequency cepstral coefficients (MFCCs) that is used to train data for the classifier. Feed-Forward Neural Network was used for the classifier and can effectively classification the stages of maturity of durian fruits with accuracy rate more than 82%.

Abstract: Understanding the structural behavior of heritage buildings is usually a very complicated task because they typically present complex deterioration and damage patterns which cannot be fully evaluated by means of visual inspections. Moreover, the reliability of such constructions largely depends on different materials, structural components and details, the health of which is often unknown or affected by great uncertainties. In this regard, the experimental dynamic testing of heritage buildings and monuments subjected to ambient vibrations has become a valuable tool for their assessment because of the minimum interference with the structure. Traffic-induced vibrations are not always a feasible dynamic load for monumental buildings due to their very low intensity or owing to existing restrictions to road and rail traffic. On the other hand, the analysis of the experimental response under earthquakes can lead to more relevant information about the dynamic behavior of historic constructions, provided that the structure is equipped with a permanent sensor network. Within this framework, the present work illustrates preliminary results carried out from time and frequency domain analyses performed on the experimental dynamic response of the leaning tower of Pisa using seismic records. The main dynamic features of the monument have been identified, and then examined taking into account the seismic input and the soil-foundation-structure interaction.

Abstract: Review of ultrasound applications in mechanical and material engineering is presented. Application examples in material thickness, profile measurement are given. Applications for load, stress, stiffness, porosity, density, viscosity, bond strength, hardening depth evaluation are discussed. Composite or polymer curing states can be monitored. Ultrasonic signal propagation velocity, attenuation or nonlinearity can be used for aforementioned parameters extraction. Signal acquisition setup configurations along with signal processing techniques are discussed. Ultrasound can be used for structure integrity testing or monitoring. Imaging of the inner material structure or properties distribution requires special reconstruction techniques. Presence of the structural noise is masking the defects. Image reconstruction and structural noise reduction techniques are outlined.

Abstract: This paper presents an acousto-optics analysis on free space optical signals modulated by two distinguishable non-resonant acoustic waves. The acoustic waves were directed at two different directions and locations along a laser beam and created non-interference modulated optical signals. The photonics microphone deploys low-powered eye-safe continuous-wave 633-nm laser; high-speed photodiode and a series of Fourier lenses. Two transducers generating 20 Hz to 20 kHz acoustic waves were directed across the laser beam. The receiving modulated signal was filtered and amplified electronically by two sets of passive bandpass filter separated by a transimpedance amplifier and connected to a computer for analysis. The signal was further digitally filtered and amplified to enhance the signal-to-noise ratio via MATLAB software. These signals were analyzed in time and frequency domains using Fast Fourier Transform (FFT) and Spectrogram. It was found that the recorded signals demonstrated higher signal intensities for lower acoustic frequencies with digital signal-to-noise ratio (SNR) ranging from 10.77 to 71.92 for frequency of 1 kHz to 20 kHz and 20 Hz to 1 kHz respectively. The frequencies of both transducers were simultaneously swept through from 20 Hz and 20 kHz respectively. These scanning frequencies approached one another and crossover with no resonant frequency was observed. This illustrates that it is able to detect multiple acoustic signals for any given frequencies along the laser beam and found its applications in stealth sound detection and long range sound sensor. Though low-powered 1-mW laser was used, a relatively high signal-to-noise ratio with clear-recorded playback was achieved.

Abstract: In this paper, the application of artificial neural network clasifier to resolve pest birds in agricultural areas as a part of a comprehensive system of protection against vermin is demonstrated. Firstly, the idea of the whole system is outlined. Then, the method of recognition is described, the process of artificial neural network design is illustrated and the classifier is validated using data gathered in the fields. Eventually, the results are compared to similar works.