signal processing
در نشریات گروه برق-
Attention deficit hyperactivity disorder (ADHD) is one of the most common mental disorders affecting children. Delayed diagnosis and treatment of ADHD might result in poor school performance. In this paper, an intelligent system is proposed for detecting ADHD from electroencephalograms. The system first preprocesses the electroencephalograms to remove the powerline and blinking interferences. Then, it applies independent component analysis to separate the signals of the sources that generate the preprocessed electroencephalograms. Later, 3 features of Shannon entropy, kurtosis, and skewness are extracted from the independent components. A total of 57 features are obtained for 19 electroencephalogram channels. Finally, two classifiers (i.e., the k-nearest neighbors with k=3, and an artificial neural network) were used to detect ADHD from the extracted features. We used a public database containing signals from 61 children with ADHD and 60 healthy children to evaluate the performance of the proposed system. The accuracy, sensitivity, and specificity of the artificial neural network were 99.92%, 99.89%, and 99.95%, respectively, while these metrics were all 100% for the k nearest neighbors. The results imply that the features extracted from independent components of electroencephalograms are more powerful than other linear/nonlinear features directly extracted from the signals.
Keywords: Attention Deficit Hyperactivity Disorder, Electroencephalogram, Independent Component Analysis, Signal Processing, Feature Extraction, ADHD, Feature Ex-Traction, Artificial Neural Network, K-Nearest Neighbors., K-Nearest Neighbors -
Journal of Artificial Intelligence in Electrical Engineering, Volume:13 Issue: 50, Summer 2024, PP 13 -19
In this paper a novel method for realization of Gaussian function is presented. The current-mode circuits are employed for the implementation of main circuits owing to the simple circuitry and intuitive configuration. Unlike the previous works which were based on the transistors worked in weak inversion region, the proposed configuration operates in the saturation region, therefore high-accuracy as well as the high-speed performance are obtained. The proposed circuit is fully programmable in terms of mean value, standard deviation and peak gain of the Gaussian function. Simulation results of the circuit is obtained by HSPICE with TSMC level 49 (BSIM3v3) parametes in 0.35μm standard CMOS process.
Keywords: Gaussian Circuit, Membership Function, Signal Processing, Current Mode -
Journal of Artificial Intelligence in Electrical Engineering, Volume:13 Issue: 49, Spring 2024, PP 1 -10
This study focuses on diagnosing gear defects in the S5-380 transmission using advanced vibration analysis and validating findings through the HÖFLER Gear Testing Machine. The research highlights key faults such as backlash, eccentricity, and shaft deflection identified via vibration measurements and confirmed using detailed gear profile and lead inspections. The vibration analysis employed V-SAM Vibrometer and V-SAM-Web Soft to detect critical parameters, including Gear Mesh Frequency (GMF) and Gear Hunting Tooth Frequency (GHTF). Results demonstrated the robustness of vibration analysis as an efficient, cost-effective alternative to Coordinate Measuring Machines (CMM) for end-of-line quality control. Furthermore, integrating vibration analysis with CMM-based validation provided precise fault identification, enabling targeted maintenance and enhanced gearbox performance. The findings underscore the potential of transitioning to AI-driven diagnostic systems in Industry 5.0 for real-time, scalable, and intelligent gearbox monitoring. This approach offers significant implications for improving durability, quality, and operational efficiency in gear manufacturing.
Keywords: Gear Fault Diagnosis, Vibration Analysis, Artificial Neural Network (ANN), Machine Learning (ML), Industry 5.0, Signal Processing -
Journal of Operation and Automation in Power Engineering, Volume:13 Issue: 1, Spring 2025, PP 52 -73This paper presents two intelligent classifier schemes for classifying the faults in a series capacitor compensated transmission line (SCCTL). The first proposed intelligent classifier scheme is a particle swarm optimization-assisted artificial neural network (PSO-ANN). The second, proposed one is a teaching-learning optimization-assisted artificial neural network (TLBO-ANN). For each type of fault, the 3-phase current signals are acquired at the sending end and processed through empirical mode decomposition (EMD), to decompose into six intrinsic mode functions. The neighborhood component analysis is used to extract the best feature intrinsic mode functions. From the identified best feature intrinsic mode functions, the energy of each phase of the line is computed. The energy of each phase is fed as inputs for both PSO-ANN and TLBO-ANN classifiers. The practicability of the proposed intelligent classifier schemes has been tested on a 500$\,kV$, 50$\,Hz$, and 300$\,km$ long line with a midpoint series capacitor using MATLAB/Simulink Software. The results demonstrate that the classifier schemes are able to accurately classify faults in less than a half-cycle. Furthermore, the efficacy of the proposed intelligent classifier schemes has been evaluated using Performance Indices including Kappa Statistics, Mean Absolute Error, Root Mean Square Error, Precision, Recall, F-measure, and Receiver Operating Characteristics. From the results of Performance Indices, it is concluded that the proposed TLBO-based artificial neural network classifier outperforms the PSO-based artificial neural network classifier. Finally, the efficacies of proposed intelligent classifier schemes are compared to existing approaches.Keywords: Artificial Intelligence, Particle Swarm Optimization-Assisted Artificial Neural Network, Teaching-Learning-Optimization-Assisted Artificial Neural Network, Power System Faults, Identification, Series Capacitor Compensation Line, Signal Processing, Empirical Mode Decomposition
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Scientia Iranica, Volume:31 Issue: 16, Sep-Oct 2024, PP 1387 -1401Chatter is a type of self-induced vibration that reflects fluctuations in both frequency and energy dispersion during the milling process, inevitably resulting in substandard part quality and diminished material removal rates. It is essential to employ a robust chatter detection method to anticipate its emergence in the early stages. This study introduces an efficient Product Function (PF) based multi-mode signal processing technique, specifically the spline-based local mean decomposition (SBLMD). This method is applied to decompose sound signals acquired through experimentation into a series of effective PF’s. Subsequently, selected PFs are employed to reconstruct a new chatter signal that is information-rich. Additionally, prediction models based on Artificial Neural Networks (ANN) are established to predict Chatter Indicator (CI) and Material Removal Rate (MRR) using three different activation algorithms: Tan Sigmoid (TANSIG), Log Sigmoid (LOGSIG), and Purely Linear (PURELIN). Statistical comparisons have been conducted in order to obtain the optimal activation algorithm and found out that data set trained with LOGSIG gives minimal error. Moreover, an optimal range of input parameters has been selected pertaining to minimum chatter and maximum MRR. Confirmation tests on the obtained set of parameters have been carried out in order to analyse and authenticate the proposed technique.Keywords: Signal Processing, Chatter Indicator, SBLMD, LM-BPNN
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یکسان بودن اندازه گام های مارپیچ در یک لامپ موج رونده با بازدهی سیستم رابطه مستقیم دارد. در این مقاله هدف ساخت دستگاهی است که با بکارگیری پردازش تصویر گام های مارپیچ را به صورت اتوماتیک و با دقت مناسب اندازه گیری نماید. به همین منظور الگوریتم پیشنهادی همراه با نو آوری هایی در زمینه های رفع نویز و تعیین آستانه در جهت اندازه گیری اتوماتیک گام های مارپیچ ارایه گردید و نمونه اولیه دستگاه ساخته شد. این دستگاه قابلیت کار در دو مد اندازه گیری دستی و اتوماتیک را داراست و مشابه داخلی نداشته و از نظر قیمت تمام شده و کاربرد در اندازه گیری گام های مارپیچ نسبت به نمونه خارجی بسیار کم هزینه تر می باشد. این دستگاه در مد اتوماتیک قادر است کلیه گام های مارپیچ را به یکباره اندازه گیری نماید. در صورتی که در دستگاه مشابه خارجی گام ها باید به صورت دستی و جداگانه اندازه گیری گردند. انتخاب نقاط ابتدا و انتهای گام ها در این دستگاه به صورت تطبیقی انجام می شود که سبب افزایش سرعت اندازه گیری و افزایش تکرارپذیری در اندازه گیری گام ها می گردد. در صورتی که در دستگاه نمونه خارجی انتخاب نقاط شروع و پایان گام ها توسط کاربر انجام می شود که خود تکرارپذیری اندازه گیری را کاهش می دهد. نتایج بدست آمده نشان می دهد که دقت اندازه گیری دستگاه ساخته شده در مقایسه با دستگاه نمونه خارجی قابل قبول می باشد.
کلید واژگان: اندازه گیری گام های مارپیچ، دستگاه اندازه گیری گام مارپیچ، پردازش تصویر، پردازش سیگنالThe same size of the helix steps in a traveling wave tube has a direct relationship with the efficiency of the system. In this article, the goal is to build a device that measures helix steps automatically and with proper accuracy by using image processing. For this purpose, the proposed algorithm was presented along with innovations in the fields of noise removal and threshold determination for the automatic measurement of helix steps, and the prototype of the device was made. This device has the ability to work in two modes of manual and automatic measurement, and it has no domestic equivalent, and it is much cheaper in terms of cost and use in measuring helix steps than the sample made abroad. In automatic mode, this device is able to measure all helix steps at once. In the case of a similar sample made abroad the steps must be measured manually and separately. The selection of the beginning and end points of steps in this device is done adaptively, which increases the speed of measurement and increases the repeatability in measuring steps. In the sample made abroad, the selection of the start and end points of the steps is done by the user, which reduces the repeatability of the measurement. The obtained results show that the measurement accuracy of the manufactured device is acceptable compared to the sample made abroad.
Keywords: Helix steps measurement, Helix steps measuring device, Image Processing, Signal Processing -
In this research, we first present some background on the sample size estimation for conducting clinical trials, discussing the necessity of a computational enrichment criterion. The Denoising Autoencoder Stacked Deep Learning (DASDL) design and development are directly motivated by the optimal enrichment design. Although there are many types of deep architectures in the literature, we focus our presentation using two of the most widely used models stacked denoising autoencoders and fully-supervised dropout. The ideas presented here are applied to any such architectures used for learning problems in the small-sample regime. In this work, we propose a novel, scalable, deep learning method that is applicable for learning problems in the small sample regime and obtains reliable performance. The results show via extensive analyses using imaging, cognitive, and other clinical data alongside a ROC curve analysis. When used as trial inclusion criteria, the new computational markers result in cost-efficient clinical Alzheimer’s disease trials with moderate sample sizes.Keywords: Pattern Analysis, Medical imaging, deep learning, Alzheimer’s disease, Signal processing
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توانایی های حرکتی و کیفیت آن ها تاثیر مستقیم و بسزایی بر کیفیت زندگی دارند. برخورد با موانع هنگام راه رفتن امری غیرقابل اجتناب است و توانایی عبور کم خطر از روی آن ها معیاری از توانایی حرکت در افراد جامعه است. گیرکردن به موانع بهنگام عبور از روی آن ها یکی از شایع ترین علل سقوط بر زمین است که خود یکی از دلایل عمده بستری شدن و مرگ و میر ناشی از جراحت در سنین بالا و بیماری پارکینسون است. الگوریتم هایی که برای پایش حرکت در افراد در معرض خطر سقوط مورداستفاده قرار می گیرند، برای بررسی تعداد و کیفیت عبور از روی موانع، نیاز به تشخیص اتوماتیک این اتفاق دارند. کارهای بسیار مختصری در زمینه این تشخیص اتوماتیک و فقط بر روی افراد سالم انجام شده است ولی ازلحاظ محاسباتی دارای الگوریتم های پیچیده ای می باشند. به علاوه موانعی که در حرکات روزمره با آن برخورد می شود، دارای ارتفاع های متنوعی می باشند که نیاز به الگوریتم با توانایی های گسترده تری برای تشخیص دارند. در این مقاله روشی مبتنی بر تبدیل موجک پیوسته ارایه شده و عملکرد آن در عبور از روی موانع کوتاه و بلند در شرکت کنندگان سالم و همچنین در بیمار پارکینسون موردبررسی قرارگرفته است. میزان صحت تشخیص اتوماتیک عبور از روی موانع توسط الگوریتم پیشنهادی برای 19 شرکت کننده سالم 5/98 درصد و برای 12 شرکت کننده بیمار پارکینسون 6/90 درصد به دست آمد. حداکثر خطا در تشخیص زمان عبور هریک از پاها 1/0 ثانیه بوده و قابلیت خوبی در تفکیک ارتفاع موانع دارد.کلید واژگان: عبور از موانع، راه رفتن، پردازش سیگنال، موجک، تشخیص اتوماتیک، سنسور پوشیدنیMobility and its quality has direct and significant effect on quality of life. Passing over obstacles is unavoidable and its safe execution is a measure of mobility for community dwellers particularly for elderly and Parkinson patients with higher risk of falling. Algorithms for monitoring mobility in high risk people, need automatic detection to examine frequency and quality of passing over obstacles. Very few attempts can be found in the literature who just focus on the healthy population who need complex algorithms. Furthermore, in real life situations, people encounter a range of obstacle heights that should be detectable in such algorithms. In this paper a wavelet-based algorithm is examined and its performance is evaluated in detection of tall and short obstacles for two groups of healthy and Parkinson participants. Accuracy of this method was 98.5% for the 19 healthy elderly participants, and 90.6% for the 12 Parkinson patients. The maximum error in detection of obstacle crossing time was 0.1 second for either feet and for both barrier heights.Keywords: Obstacle crossing, walking over, signal processing, Wavelet, automatic detection, wearable sensor
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International Journal of Industrial Electronics, Control and Optimization, Volume:3 Issue: 2, Spring 2020, PP 173 -185This paper aimed to formulate image noise reduction as an optimization problem and denoise the target image using matrix low rank approximation. Considering the fact that the smaller pieces of an image are more similar (more dependent) in natural images; therefore, it is more logical to use low rank approximation on smaller pieces of the image. In the proposed method, the image corrupted with AWGN (Additive White Gaussian Noise) is locally denoised, and the optimization problem of low rank approximation is solved on all fixed-size patches (Windows with pixels needing to be processed). This method can be implemented in parallelly for practical purposes, because it can simultaneously handle different image patches. This is one of the advantages of this method. In all noise reduction methods, the two factors, namely the amount of the noise removed from the image and the preservation of the edges (vital details), are very important. In the proposed method, all the new ideas including the use of TI image (Training Image) and SVD adaptive basis, iterability of the algorithm and patch labeling have all been proved efficient in producing sharper images, good edge preservation and acceptable speed compared to the state-of-the-art denoising methods.Keywords: Optimal Low Rank Approximation, SVD, Signal Denoising, Image Denoising, Signal Processing
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Scientia Iranica, Volume:26 Issue: 6, Nov-Dec 2019, PP 3125 -3139This paper presents a method for structural damage localization based on signal processing using generalized S-transform (SGS). The S-transform is the combinations of the properties of the short-time Fourier transform (STFT) and wavelet transform (WT) that has been developed over the last few years in an attempt to overcome inherent limitations of the wavelet and short time Fourier transform in Time-Frequency representation of non-stationary signals. The generalized type of this transform is the SGS-transform that has adjustable Gaussian window width in the time-frequency representation of signals. In this research, the SGS-transform has been employed due to its favorable performance in detection of the structural damages. The performance of the proposed method has been verified by means of three numerical examples and also the experimental data obtained from the vibration test of 8-DOFs mass–stiffness system. By way of the comparison between damage location obtained from the proposed method and simulation model, it was concluded that the method is sensitive to the damage existence and clearly demonstrates the damage location.Keywords: Damage localization, signal processing, Generalized S-transform, Time-frequency representation, Non-stationary signals
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در طول دو دهه اخیر بحث شناسایی خرابی و پایش سلامت سازه ها با هدف کاهش هزینه نگهداری و بهبود ایمنی و قابلیت اطمینان سازه مورد توجه قرار گرفته است. پس از وقوع زلزله با توجه به وضعیت بحرانی موجود و تعداد زیاد سازه های بلند مرتبه امکان مراجعه حضوری به تک تک سازه ها وجود ندارد. این موضوع اهمیت توسعه روش هایی که بتوانند تنها با استفاده از سیگنال های پاسخ ثبت شده در مدت زمان زلزله، خسارت ایجاد شده در سازه را شناسایی کنند، برجسته تر می سازد. بسیاری از روش های موجود به خصوص روش های مبتنی بر پردازش سیگنال قادر به تعیین شدت خسارت نیستند، در حالی که تعیین شدت به عنوان یکی از اهداف اصلی شناسایی خسارت در تعیین اولویت ها و مدیریت بحران پس از وقوع زلزله نقش به سزایی دارد. در این مقاله تلاش شده است تا با بهره گیری از ابزار های پردازش سیگنال و هوش مصنوعی ویژگی های حساس به خسارت به گونه ای تعیین شوند که بتوان وجود آسیب، محل و شدت آن را تنها با استفاده از سیگنال های پاسخ ارتعاشی ثبت شده در مدت زمان زلزله، با دقت مناسب تعیین کرد. در ابتدا سه روش پردازش سیگنال زمان-فرکانس آنی مورد ارزیابی و مقایسه قرار می گیرند و روش EMD به عنوان روشی با بهترین عملکرد برای هدف شناسایی خسارت انتخاب می شود. سپس معیار خسارت مناسبی بر اساس سیگنال های خروجی از سنسور های جاسازی شده در سازه با بهره گیری از EMD استخراج می شود و در نهایت الگوریتمی برای شناسایی خسارت سازه ای ارائه و روی سازه بنچ مارک پایش سلامت سازه ASCE IASC- اعمال می شود. نتایج حاکی از آن است که تلفیق تکنیک پردازش سیگنال با هوش مصنوعی کمک شایانی به تحقق اهداف سه گانه شناسایی خسارت داشته است.کلید واژگان: شناسایی خسارت، پایش سلامت سازه ها، شاخص خسارت، پردازش سیگنال، شبکه عصبی مصنوعیOver the last two decades, extensive research has been conducted on structural health monitoring and damage detection in order to reduce the life-cycle cost of structures and improve their reliability and safety. These methods are divided into modal-based and signal-based approaches. Recent advances in the field of sensor technologies have facilitated the use of signal-based methods as practical solution to detect damages in structures. After a sever earthquake, usually there is no possibility for visiting the individual structures. Therefore, application of methods that can detect damage of structures only by using signals recorded at the time of the earthquake is noteworthy. Many existing methods, especially methods based on signal processing are not able to determine the damage severity. This article presents a signal-based seismic structural health monitoring technique for damage detection and evaluating damage severity of a multi-story frame subjected to an earthquake event. As a case study, this article is focused on IASCASCE benchmark problem to provide possibility for side-by-side comparison. First three signal processing techniques including EMD, HVD and LMD, which are categorized as instantaneous time-frequency methods, have been compared to find a method with the best resolution in extracting frequency responses. Based on the results EMD has proved to outperform than the others. Second, EMD is used to extract the acceleration response of the sensors. Results show that by taking advantage of signal processing and artificial intelligence techniques in this research, damage detection of structures was carried out for three levels including damage occurrence, damage severity and location of the damage.Keywords: Damage detection, Structural Health Monitoring, Damage Index, Signal Processing, Neural network
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Use of efficient signal processing tools (SPTs) to extract proper indices for fault detection in induction motors (IMs) is the essential part of any fault recognition procedure. The Par 1 of the two parts paper focuses on Fourier-based techniques including fast Fourier transform and short time Fourier transform. In this paper, all utilized SPTs which have been employed for fault fetection in IMs are analyzed in details. Then, their competency and their drawbacks for extracting indices in transient and steady state modes are criticized from different aspects. The considerable experimental results are used tocertificate demonstrated discussion. Different kinds of faults, including eccentricity, broken bar and bearing faults as major internal faults, in IMs are investigated. The use of efficient signal processing tools (SPTs) to extract proper indices for faultdetection in induction motors (IMs) is the essential part of any fault recognitionprocedure. In the first part of the present paper, we focus on Fourier-based techniques, including fast Fourier transform and short time Fourier transform. In this paper, all utilized SPTs which have been employed for fault detection in IMs are analyzed in detail. Then, their competency and their drawbacks to extract indices in transient and steady state modes are criticized from different aspects. Different kinds of faults, namely, eccentricity, broken bar, and bearing faults as the major internal faults in IMs, are investigated.
Keywords: Fault diagnosis, induction motors, Signal Processing, Fourier transform, eccentricity fault, broken bars fault, bearing fault -
An important issue in power generation and petrochemical industries is monitoring pipe wall thickness and corrosion/erosion rate. In this thesis, a combination of signal processing techniques are used to estimate the corrosion rate estimates based on MBE. Corrosion rate is estimated based on ultrasonic pipe wall thickness data is collected over a short period of time using MBE model. This technique is based on data collected from the speedometer applied for thinning and both indicate that they were able to estimate the rate of corrosion in short periods of time and with good accuracy.Keywords: Ultrasonic, Pipe Corrosion, Model, Based Estimation, Signal processing
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Journal of Artificial Intelligence and Data Mining, Volume:3 Issue: 1, Winter-Spring 2015, PP 93 -100The focus of this paper is to consider the compressed sensing problem. It is stated that the compressed sensing theory, under certain conditions, helps relax the Nyquist sampling theory and takes smaller samples. One of the important tasks in this theory is to carefully design measurement matrix (sampling operator). Most existing methods in the literature attempt to optimize a randomly initialized matrix with the aim of decreasing the amount of required measurements. However, these approaches mainly lead to sophisticated structure of measurement matrix which makes it very difficult to implement. In this paper we propose an intermediate structure for the measurement matrix based on random sampling. The main advantage of block-based proposed technique is simplicity and yet achieving acceptable performance obtained through using conventional techniques. The experimental results clearly confirm that in spite of simplicity of the proposed approach it can be competitive to the existing methods in terms of reconstruction quality. It also outperforms existing methods in terms of computation time.Keywords: Compressed Sensing, Sparse Recovery, Signal Processing, Random Sampling, Matching Pursuit, Measurement Matrix
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در سالهای اخیر روش های تشخیص خرابی برای سازه های عمران و مکانیک، در زمینه های مختلفی گسترش پیدا کرده اند. تبدیل موجک، یک ابزار نسبتا جدید ریاضی برای پردازش سیگنال می باشد که اطلاعات بیشتری در سیگنال های غیر ایستا، که تبدیل فوریه از ارائه آن ها عاجز بود، را فراهم می آورد. یکی از حوزه های مهم پر کاربرد تبدیل های ریاضی مانند موجک، تشخیص خرابی در سازه ها می باشد، به خصوص که شناسایی آسیب در مراحل اولیه شروع آن در سازه حائز اهمیت می باشد. در این مقاله روش ساده ای بر مبنای تحلیل موجک برای تشخیص محل و میزان آسیب در تیر ها، بررسی شده است؛ بدین صورت که پاسخ تغییر شکل قائم تیر تحت بار استاتیکی ثابت را با استفاده از تبدیل موجک گسسته تجزیه شده و در نمودارهای تجزیه شده برای سناریوهای مختلف آسیب در تیر بحث و بررسی به عمل آمده است و در نهایت کارایی روش برای حالات مختلف ترک خوردگی مورد بررسی و ارزیابی قرار گرفته است.
کلید واژگان: تشخیص آسیب، تیر، تبدیل موجک، پردازش سیگنالIn recent years, damage detection and structural health monitoring methods for civil and mechanical structures, have been developed in different fields. Structural health monitoring is the implementation of a damage identification strategy to the civil engineering infrastructures. Damage is defined as changes to the material and/or geometric properties of these systems, including changes to the boundary conditions and system connectivity. Damage affects the current or future performance of such systems. Structural health monitoring and damage detection has several techniques, the methods are categorized based on the type of measured data used, and/or the technique used to identify the damage from the measured data. Wavelet transform is relatively new mathematical tool for signal processing. Wavelet transform gives more information on non-stationary signal that the Fourier transform was unable to provide them. One of the most important issue of application of the mathematical transforms such as wavelet, is structural health monitoring and structural damage detection. Especially the identification of damage in structures at the beginning is important. In this paper a simple method based on Wavelet transform has been utilized in order to localize and quantify the crack in simple supported beam; in which, the deflection of the beam subject to static loading would be decomposed by discrete wavelet transforms. In decomposition diagrams has been assessed for various scenarios of damage. Finally the performance of the applied method has been evaluated for different state of cracking.Keywords: Damage Detection, Beam, Wavelet Transform, Signal Processing
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