Search for: detection-algorithm
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    A new delay attack detection algorithm for PTP network in power substation

    , Article International Journal of Electrical Power and Energy Systems ; Volume 133 , 2021 ; 01420615 (ISSN) Moradi, M ; Jahangir, A. H ; Sharif University of Technology
    Elsevier Ltd  2021
    Time synchronization is one of the main issues for guaranteeing the correctness of actions depending on the time of measured data or detected events by electronic devices across industrial networks. According to the accuracy needed in different applications and networks, several synchronization protocols or algorithms have been proposed so far. The Precision Time Protocol, PTP, is one of the most accurate synchronization protocols introduced for automation applications. It has also been used in power grids and digital substations. However, due to the variety of cyber-attacks in electrical power systems in recent years, its security should be considered and evaluated as other substation... 

    A 13 Gbps, 0.13 μm CMOS, multiplication-free MIMO detector

    , Article Journal of Signal Processing Systems ; Volume 88, Issue 3 , 2017 , Pages 273-285 ; 19398018 (ISSN) Mahdavi, M ; Shabany, M ; Sharif University of Technology
    A novel ultra high-throughput detection algorithm with an efficient VLSI architecture for high-order MIMO detectors in the complex constellations is proposed. The main contributions include a new method for the node generation in complex-domain, pipelinable sorters, and a simple combinational circuit instead of the conventional multipliers, which makes the proposed architecture multiplication-free. The proposed design achieves an SNR-independent throughput of 13.3 Gbps at the clock frequency of 556 MHz in a 0.13 μm CMOS technology with a near ML performance. The implemented design consumes 90 pJ per detected bit with the initial latency of 0.3 μs. Also, the synthesis results in a 90 nm CMOS... 

    Histogram based reflection detection

    , Article 2011 7th Iranian Conference on Machine Vision and Image Processing, MVIP 2011 - Proceedings, 16 November 2011 through 17 November 2011 ; November , 2011 , Page(s): 1 - 5 ; 978-1457715334 ; 9781457715358 (ISBN) Ahmadi, A ; Ahani, S ; Khalilian, H ; Gholampour, I ; Sharif University of Technology
    Reflection appears as a layer that partly covers the original image. This phenomenon may cause failure in extracting information from images of reflecting objects. This work presents an automated technique for determining of reflection area as well as its severity to define reliability of extracted information. This is done by analyzing histogram and objects found in the image. We present a strong detector based on combining the results of these two procedures. We presented new reflection detection algorithm and a new method to find a good threshold value for converting any image into a binary image. The average reflection detection accuracy of the proposed algorithm is more than 95% for... 

    Enhancing physionet electrocardiogram records for fetal heart rate detection algorithm

    , Article Proceedings - 2015 2nd International Conference on Biomedical Engineering, ICoBE 2015 ; 2015 ; 9781479917495 (ISBN) Yusuf, W. Y. W ; Ali, M. A. M ; Zahedi, E ; Sharif University of Technology
    The noninvasive fetal electrocardiogram (ECG) data available from Physionet data bank are suitable for developing fetal heart rate (FHR) detection algorithms. The data have been collected from single subject with a broad range of gestation weeks, and have a total data length of more than 9 hours arranged in 55 data sets. However, there are three additional data features which are currently not directly available from Physionet to facilitate the easy usage of these data: (1) the fetal peak visibility evaluation, (2) the gestation week, and (3) the data length. This article presents an improvement to the data bank by providing the additional features. The required pre-processing of the data is... 

    Fast fault detection method for modular multilevel converter semiconductor power switches

    , Article IET Power Electronics ; Volume 9, Issue 2 , 2016 , Pages 165-174 ; 17554535 (ISSN) Haghnazari, S ; Khodabandeh, M ; Zolghadri, M. R ; Sharif University of Technology
    Institution of Engineering and Technology  2016
    This study proposes a new fault detection method for modular multilevel converter (MMC) semiconductor power switches. While in common MMCs, the cells capacitor voltages are measured directly for control purposes, in this study voltage measurement point changes to the cell output terminal improving fault diagnosis ability. Based on this measurement reconfiguration, a novel fault detection algorithm is designed for MMCs semiconductor power switches. The open circuit and short circuit faults are detected based on unconformity between modules output voltage and switching signals. Simulation and experimental results confirm accurate and fast operation of the proposed method in faulty cell... 

    A collusion-resistant video watermarking scheme

    , Article 8th International Workshop on Information Hiding, IH 2006, Alexandria, VA, 10 June 2006 through 12 June 2006 ; Volume 4437 LNCS , 2007 , Pages 343-354 ; 03029743 (ISSN); 9783540741237 (ISBN) Houmansadr, A ; Ghaemmaghami, S ; Sharif University of Technology
    Springer Verlag  2007
    A video watermarking scheme is proposed in this paper using the concept of the secret sharing scheme. The owner's mark is split into twin shares, where the shares are inserted into the video frames in the spatial domain in a simple manner. The detection algorithm uses a linear function applied to the twin shares to reconstruct the secret. This makes the watermarked video sequence robust against pirate attacks, such as frame averaging and frame swapping. Due to the compatibility of the exploited secret sharing scheme to geometrical distortions, the watermarking system is also robust to this kind of processing schemes. On account of insertion of various marks into different frames, which are... 

    Novel MIMO detection algorithm for high-order constellations in the complex domain

    , Article IEEE Transactions on Very Large Scale Integration (VLSI) Systems ; Volume 21, Issue 5 , 2013 , Pages 834-847 ; 10638210 (ISSN) Mahdavi, M ; Shabany, M ; Sharif University of Technology
    A novel detection algorithm with an efficient VLSI architecture featuring efficient operation over infinite complex lattices is proposed. The proposed design results in the highest throughput, the lowest latency, and the lowest energy compared to the complex-domain VLSI implementations to date. The main innovations are a novel complex-domain means of expanding/visiting the intermediate nodes of the search tree on demand, rather than exhaustively, as well as a new distributed sorting scheme to keep track of the best candidates at each search phase. Its support of unbounded infinite lattice decoding distinguishes the present method from previous K-Best strategies and also allows its complexity... 

    Fast fourier transform based NDT approach for depth detection of hidden defects using HTS rf-SQUID

    , Article IEEE Transactions on Applied Superconductivity ; Volume 28, Issue 7 , 2018 ; 10518223 (ISSN) Rostami, B ; Shanehsazzadeh, F ; Fardmanesh, M ; Sharif University of Technology
    We present a new approach for depth detection of hidden defects based on the analysis of the frequency spectrum of the output waveform in a nondestructive testing (NDT) system. In our eddy current Superconducting quantum interference device (SQUID) based NDT system, we apply multiple frequencies to its single excitation coil in a magnetically unshielded environment. The excitation coil is a planar D-shaped printed circuit board coil, and a high-Tc gradiometer YBCO rf-SQUID is used as the electromagnetic sensor in this system. An automated two-dimensional nonmagnetic scanning robot is used to test samples with intentional defects at different depths. In this approach, a diagram labeled 'FFT... 

    Wisecode: Wise image segmentation based on community detection

    , Article Imaging Science Journal ; Vol. 62, Issue 6 , 2014 , pp. 327-336 ; Online ISSN: 1743131X Abin, A. A ; Mahdisoltani, F ; Beigy, H ; Sharif University of Technology
    Image segmentation is one of the fundamental problems in image processing and computer vision, since it is the first step in many image analysis systems. This paper presents a new perspective to image segmentation, namely, segmenting input images by applying efficient community detection algorithms common in social and complex networks. First, a common segmentation algorithm is used to fragment the image into small initial regions. A weighted network is then constructed. Each initial region is mapped to a vertex, and all these vertices are connected to each other. The similarity between two regions is calculated from colour information. This similarity is then used to assign weights to the... 

    Ultra high-throughput architectures for hard-output MIMO detectors in the complex domain

    , Article Midwest Symposium on Circuits and Systems, 7 August 2011 through 10 August 2011l ; August , 2011 ; 15483746 (ISSN) ; 9781612848570 (ISBN) Mahdavi, M ; Shabany, M ; Sharif University of Technology
    In this paper, a novel hard-output detection algorithm for the complex multiple-input multiple-output (MIMO) detectors is proposed, which results in a significant throughput enhancement, a near-ML performance, and an SNR-independent fixed-throughput. Moreover, a high-throughput VLSI implementation is proposed, which is based on a novel method of the node generation and sorting scheme. The proposed design achieves the throughput of 10Gbps in a 0.13 μ CMOS process, which is the highest throughput reported in the literature for both the real and the complex domains. Synthesis results in 90nm CMOS also show that the proposed scheme can achieve the throughput of up to 15Gbps. Moreover, the FPGA... 

    A new decoding scheme for errorless codes for overloaded CDMA with active user detection

    , Article 2011 18th International Conference on Telecommunications, ICT 2011, Ayia Napa, 8 May 2011 through 11 May 2011 ; 2011 , Pages 201-205 ; 9781457700248 (ISBN) Mousavi, A ; Pad, P ; Delgosha, P ; Marvasti, F ; Sharif University of Technology
    Recently, a new class of binary codes for overloaded CDMA systems are proposed that not only has the ability of errorless communication but also suitable for detecting active users. These codes are called COWDA. In [1], a Maximum Likelihood (ML) decoder is proposed for this class of codes. Although the proposed scheme for coding/decoding shows impressive performance, the decoder can be significantly improved. In this paper, by assuming practical conditions for the traffic in the system, we suggest and prove an algorithm that increases the performance of the decoder several orders of magnitude (the Bit-Error-Rate (BER) is divided by a factor of about 400 in some E b/N0's). The algorithm... 

    A fast enhanced algorithm of PRI transform

    , Article Proceedings - 6th International Symposium on Parallel Computing in Electrical Engineering, PARELEC 2011, 4 April 2011 through 5 April 2011 ; April , 2011 , Pages 179-184 ; 9780769543970 (ISBN) Mahdavi, A ; Pezeshk, A. M ; Sharif University of Technology
    The problem of estimating pulse repetition interval (PRI) of an interleaved pulse train which consist of several independent radar signals, is the main issue of signal processing in electronic support systems. PRI Transform algorithm is one of the well known and effective methods of PRI detection which is capable of detecting several close jittered signals and surpassing subharmonics, but have some drawbacks especially because of small PRI dynamic range and heavy computations. In this paper a modified PRI transform is introduced which manage wide range of PRIs simultaneously, and speed up the algorithm by significantly reducing the computations. Moreover an efficient threshold is set for... 

    A fully analog calibration technique for phase and gain mismatches in image-reject receivers

    , Article AEU - International Journal of Electronics and Communications ; Volume 69, Issue 5 , May , 2015 , Pages 823-835 ; 14348411 (ISSN) Nikoofard, A ; Kananian, S ; Fotowat Ahmady, A ; Sharif University of Technology
    Elsevier GmbH  2015
    A systematic approach to I/Q mismatch calibration in image-reject receivers is presented in this paper. A new error detection algorithm is proposed, which automatically calibrates for phase and gain mismatches limiting the performance of image-reject receivers. A dual-loop feedback is employed which looks for the minimum phase/gain error using a 2-dimensional analog-based search algorithm and then finds the minimum value for the error. An experimental CMOS prototype RF front-end for cognitive radio applications operating at 400-800 MHz is proposed and simulated in the 0.18 μm CMOS technology, achieving an image rejection ratio (IRR) better than 55-dB in post-layout simulation. The... 

    Sliding Mode Observers to Detect and Isolate Faults in a Turbocharged Gasoline Engine

    , Article SAE International Journal of Engines ; Volume 8, Issue 2 , April , 2015 , Pages 399-410 ; 19463936 (ISSN) Salehi, R ; Alasty, A ; Vossoughi, G. R ; Sharif University of Technology
    SAE International  2015
    This paper presents a novel model-based algorithm which is able to detect and isolate major faults assigned to the gas exchange path of a gasoline engine both in the intake and exhaust sides. The diagnostics system is developed for detection and isolation of these faults: air leakage fault between the compressor and the air throttle, exhaust manifold pressure sensor fault, wastegate stuck-closed fault and wastegate stuck-open fault. Sliding mode observers (SMOs) are the core detection algorithms utilized in this work. A first order SMO is designed to estimate the turbocharger rotational dynamics. The wastegate displacement dynamics coupled to the exhaust manifold pressure dynamics is... 

    Damage identification in multi-step waveguides using Lamb waves and scattering coefficients

    , Article Archive of Applied Mechanics ; Volume 88, Issue 6 , June , 2018 , Pages 1009-1026 ; 09391533 (ISSN) Ghadami, A ; Behzad, M ; Mirdamadi, H. R ; Sharif University of Technology
    Springer Verlag  2018
    Damage detection in uniform structures has been studied in numerous previous researches. However, damage detection in non-uniform structures is less studied. In this paper, a damage detection algorithm for identifying rectangular notch parameters in a stepped waveguide using Lamb waves is presented. The proposed algorithm is based on mode conversion and scattering phenomena because of interaction of Lamb wave modes with defects. The analysis is divided into two steps: notch localization and notch geometry detection. The main advantage of this method is its ability to detect all of the notch parameters in a waveguide with arbitrary number of step discontinuities. The method is applied to a... 

    Improvement of fault detection in wireless sensor networks

    , Article 2009 Second ISECS International Colloquium on Computing, Communication, Control, and Management, CCCM 2009, Sanya, 8 August 2009 through 9 August 2009 ; Volume 4 , 2009 , Pages 644-646 ; 9781424442461 (ISBN) Khazaei, E ; Barati, A ; Movaghar, A ; Yangzhou University; Guangdong University of Business Studies; Wuhan Institute of Technology; IEEE SMC TC on Education Technology and Training; IEEE Technology Management Council ; Sharif University of Technology
    This paper presents a centralized fault detection algorithm for wireless sensor networks. Faulty sensor nodes are identified based on comparisons between neighboring nodes and own central node and dissemination of the decision made at each node. RNS system is used to tolerate transient faults in sensing and communication. In this system, arithmetic operations act on residues - reminder of dividing original number in several definite modules - in parallel. Consequently computations on these residues which are smaller than the original number are performed, so speed up arithmetic and decreased power consumption is achieved. ©2009 IEEE  

    ARAE: Adversarially robust training of autoencoders improves novelty detection

    , Article Neural Networks ; Volume 144 , 2021 , Pages 726-736 ; 08936080 (ISSN) Salehi, M ; Arya, A ; Pajoum, B ; Otoofi, M ; Shaeiri, A ; Rohban, M. H ; Rabiee, H. R ; Sharif University of Technology
    Elsevier Ltd  2021
    Autoencoders have recently been widely employed to approach the novelty detection problem. Trained only on the normal data, the AE is expected to reconstruct the normal data effectively while failing to regenerate the anomalous data. Based on this assumption, one could utilize the AE for novelty detection. However, it is known that this assumption does not always hold. Such an AE can often perfectly reconstruct the anomalous data due to modeling low-level and generic features in the input. We propose a novel training algorithm for the AE that facilitates learning more semantically meaningful features to address this problem. For this purpose, we exploit the fact that adversarial robustness... 

    A new framework based on recurrence quantification analysis for epileptic seizure detection

    , Article IEEE Journal of Biomedical and Health Informatics ; Volume 17, Issue 3 , 2013 , Pages 572-578 ; 21682194 (ISSN) Niknazar, M ; Mousavi, S. R ; Vosoughi Vahdat, B ; Sayyah, M ; Sharif University of Technology
    This study presents applying recurrence quantification analysis (RQA) on EEG recordings and their subbands: delta, theta, alpha, beta, and gamma for epileptic seizure detection. RQA is adopted since it does not require assumptions about stationarity, length of signal, and noise. The decomposition of the original EEG into its five constituent subbands helps better identification of the dynamical system of EEG signal. This leads to better classification of the database into three groups: Healthy subjects, epileptic subjects during a seizure-free interval (Interictal) and epileptic subjects during a seizure course (Ictal). The proposed algorithm is applied to an epileptic EEG dataset provided... 

    Real time simulation of grasping procedure of large internal organs during laparoscopic surgery

    , Article Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS ; 2012 , Pages 924-927 ; 1557170X (ISSN) ; 9781424441198 (ISBN) Dehghani Ashkezari, H ; Mirbagheri, A ; Farahmand, F ; Behzadipour, S ; Firoozbakhsh, K ; Sharif University of Technology
    Surgical simulation systems facilitate safe and efficient training processes of surgical trainees by providing a virtual environment in which the surgical procedure can be repeated unlimitedly in a wide variety of situations. The present study attempted to develop a real time simulation system for the grasping procedure of large internal organs during laparoscopic surgery. A mass-spring-damper model was developed to simulate the nonlinear viscoelastic large deformations of the spleen tissue while interacting with a triple-jaw grasper. A novel collision detection algorithm was designed and implemented to determine the contact points between the tissue and the grasper jaws. Force or... 

    Noise cancelation of epileptic interictal EEG data based on generalized eigenvalue decomposition

    , Article 2012 35th International Conference on Telecommunications and Signal Processing, TSP 2012 - Proceedings ; 2012 , Pages 591-595 ; 9781467311182 (ISBN) Hajipour, S ; Shamsollahi, M. B ; Albera, L ; Merlet, I ; Sharif University of Technology
    Denoising is an important preprocessing stage in some Electroencephalography (EEG) applications such as epileptic source localization. In this paper, we propose a new algorithm for denoising the interictal EEG data. The proposed algorithm is based on Generalized Eigenvalue Decomposition of two covariance matrices of the observations. Since one of these matrices is related to the spike durations, we should estimate the occurrence time of the spike peaks and the exact spike durations. To this end, we propose a spike detection algorithm which is based on the available spike detection methods. The comparison of the results of the proposed algorithm with the results of two well-known ICA...