Search for: signal-detection
Total 114 records
Article IEEE 2007 Radar Conference, Waltham, MA, 17 April 2007 through 20 April 2007 ; 2007 , Pages 481-486 ; 1424402840 (ISBN); 9781424402847 (ISBN) ; Nayebi, M. M ; Sharif University of Technology
Using the Fractal Geometry in Signal processing has been extended nowadays . They have found several applications in signal detection and recognitions. They use the chaotic feature of the noise and clutter and try to distinguish between the noise, clutter and the desired target  . Recent works show that lots of clutters like sea and ground clutters have fractal behavior so this kind of approach to the signal detection has been extended these days. In this paper we have used the Box-Counts of a signal rather than the Fractal dimension of a signal as will be defined later in the text. By applying the new defined concept we have developed different methods of signal detection. We...
Article Signal Processing ; Volume 88, Issue 3 , 2008 , Pages 624-638 ; 01651684 (ISSN) ; Jahani Yekta, M. M ; Marvasti, F ; Sharif University of Technology
In this paper an iterative method for recovery of the missing samples of signals is investigated in detail, and some novel linear, nonlinear, and adaptive extrapolation techniques are proposed to be used along with it to increase the convergence rate of the recovery system. The proposed methods would remarkably speed up the convergence rate, save processing power, and reduce the delay of the system compared to some well known accelerated versions of the aforementioned iterative algorithm. © 2007 Elsevier B.V. All rights reserved
Article 2004 International Conference on Power System Technology, POWERCON 2004, 21 November 2004 through 24 November 2004 ; Volume 2 , 2004 , Pages 1863-1868 ; 0780386108 (ISBN); 9780780386105 (ISBN) ; Blackburn, T. R ; Phung, B. T ; Zhang, H ; Sharif University of Technology
Online monitoring of HV XLPE cables is a major interest for utilities. Due to severe and rapid risk of life of this type of cable with occurrence of partial discharges, studies are carried out for detection and location of PD. However there is a lack of models that can help to accurately detect the partial discharge and its location in installed cables, due to the relatively long length and the load condition of cable. Detection and location of any partial discharge signal requires: A verified knowledge of phenomena which contributes to P.D. propagation and its deformation, measured data of P.D. type signal propagation on different cable test setups, accurate frequency dependent cable model...
Article International Journal of Communication Systems ; 2015 ; 10745351 (ISSN) ; Jahangir, A. H ; Sharif University of Technology
SUMMARY: In this paper, we study the effects of anomalies on the distribution of TCP flow interarrival time process. We show empirically that despite the variety of data networks in size, number of users, applications, and load, the interarrival times of normal flows comply with the Weibull distribution, whereas specific irregularities (anomalies) causes deviations from the distribution. We first estimate the scale and shape parameters and then check the discrepancy of the data from a Weibull distribution with the estimated parameters. We also utilize the Weibull counting model to recheck the conformance of small flow interarrival times with the distribution. We perform our experiments on a...
Article Signal Processing ; Volume 88, Issue 8 , August , 2008 , Pages 2114-2121 ; 01651684 (ISSN) ; Farsi, A ; Ghaed, M. H ; Karimi Ghartemani, M ; Sharif University of Technology
This paper studies the subject of adaptive noise cancelation using the Kalman filtering technique to achieve high precision and fast convergence. It is shown that the Kalman filter can successfully be designed to detect and extract periodic noises which may be constituted of different sinusoidal components with possibly unknown and/or time-varying frequencies. This highlights the feature of Kalman filter in synthesizing periodic noises in the time-domain which is not possible using Fourier-based methods such as DFT. Usefulness of the method is discussed in the context of two examples: active cancelation of periodic noises from audio waveforms and filtering of electrocardiogram measurements....
Article IEICE Transactions on Communications ; Volume E91-B, Issue 2 , 2008 , Pages 543-552 ; 09168516 (ISSN) ; Taban, M. R ; Nayebi, M. M ; Sharif University of Technology
Institute of Electronics, Information and Communication, Engineers, IEICE 2008
In Distributed detection systems, restricting the output of the local decision to one bit certainly implies a substantial information loss. In this paper, we consider the fuzzy detection, which uses a function called membership function for mapping the observation space of each local detector to a value between 0 and 1, indicating the degree of assurance about presence or absence of a signal. In this case, we examine the problem of distributed Maximum Likelihood (ML) and Order Statistic (OS) constant false alarm rate (CFAR) detections using fuzzy fusion rules such as "Algebraic Product"(AP), "Algebraic Sum"(AS), "Union"(Un) and " Intersection"(IS) in the fusion centre. For the Weibull...
Article 18th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC'07, Athens, 3 September 2007 through 7 September 2007 ; December , 2007 ; 1424411440 (ISBN); 9781424411443 (ISBN) ; Nasiri Kenari, M ; Jamshidi, A ; Sharif University of Technology
Rcent measurements suggest the possibility of sharing spectrum among different parties subject to interference-protection constraints. In order to enable access to an unused licensed spectrum, a secondary user has to monitor licensed bands and opportunistically transmit whenever no primary signal is detected. In this paper, we study spectrum-sharing between a primary licensee and a group of secondary users. The structure of an asymptotically optimum detector based on the measurements of all secondary users is derived and the effect of the quantization error in such a system is evaluated. The results show the superiority of the proposed detector to other schemes. © 2007 IEEE
Article 3rd International Symposium on Stochastic Algorithms: Foundations and Applications, SAGA 2005, Moscow, 20 October 2005 through 22 October 2005 ; Volume 3777 LNCS , 2005 , Pages 95-106 ; 03029743 (ISSN); 3540294988 (ISBN); 9783540294986 (ISBN) ; Pourtakdoust, S. H ; Russian Foundation for Basic Research ; Sharif University of Technology
The well-known ant colony optimization meta-heuristic is applied to design a new command to line-of-sight guidance law. In this regard, the lately developed continuous ant colony system is used to optimize the parameters of a pre-constructed fuzzy sliding mode controller. The performance of the resulting guidance law is evaluated at different engagement scenarios. © Springer-Verlag Berlin Heidelberg 2005
Article IECON 2004 - 30th Annual Conference of IEEE Industrial Electronics Society, Busan, 2 November 2004 through 6 November 2004 ; Volume 2 , 2004 , Pages 1469-1474 ; Parniani, M ; Mokhtari, H ; Sharif University of Technology
This paper discusses the application of unified power quality conditioner (UPQC) for improving power quality of a system supplying an electric arc furnace (EAF). The UPQC comprises a combined series and shunt active filters sharing a common DC link. It is used to mitigate voltage disturbances and compensate for reactive power, harmonics and interharmonics. A novel control strategy of the UPQC is presented. Since voltages at the point of common coupling (PCC) contain low frequency interharmonics, conventional methods can not be used for extracting voltage reference signals. In the proposed method, voltage references are extracted using active power processing to generate sinusoidal waveforms....
Article Journal of Optical Networking ; Volume 6, Issue 9, 1 September 2007, Pages 1138-1178 ; Sharif University Of Technology
I present an in-depth review of the trends and the directions taken by researchers worldwide in optical code-division multiple-access (OCDMA) systems. I highlight those trends and features that I believe are essential to the successful introduction of various OCDMA techniques in communication systems and data networks in the near future. In particular I begin by giving a comprehensive review of the construction of optical orthogonal codes (OOCs). Specifically I discuss the recently developed algorithms that are based on matrix algebra, which simplify and enhance the efficiencies of algorithms in OOC generation. In communication systems studies I first focus on and discuss various OCDMA...
Article 2013 IEEE Photonics Conference, IPC 2013 ; 2013 , Pages 539-540 ; 9781457715075 (ISBN) ; Chen, L. R ; Zhuge, Q ; Malekiha, M ; Marvasti, F ; Plant, D. V ; Sharif University of Technology
We propose and experimentally demonstrate a receiver structure for direct detection optical orthogonal frequency-multiplexing systems that improves the spectral efficiency by reducing the guard band between the carrier and the OFDM signal while mitigating signal-signal mixing interference
Theoretical investigation of the capture effect in intensity-modulation direct-detection microwave photonic links, Article Applied Optics ; Volume 52, Issue 28 , 2013 , Pages 7011-7021 ; 1559128X (ISSN) ; Banai, A ; Sharif University of Technology
Optical Society of American (OSA) 2013
We introduce the capture effect concept in microwave photonic links (MWPLs) for the first time to our knowledge. The capture effect or the small-signal suppression is the change in the amplitude ratio of the two signals between input and output of the intensity-modulation direct-detection (IMDD) MWPLs. An analytical explanation of the performance of external IMDD MWPLs due to the effects of nonlinearity combined with sum of several input sinusoidal signals is given.We have investigated the suppression of a weaker signal in these links. General analytic expression for the small-signal suppression is derived using a nonlinear analytical approach. We show that the small-signal suppression is...
Article 2011 International Symposium on Artificial Intelligence and Signal Processing, AISP 2011, 15 June 2011 through 16 June 2011 ; June , 2011 , Pages 31-36 ; 9781424498345 (ISBN) ; Beigy, H ; Sharif University of Technology
The voluminous of the e-mails are spam. Several algorithms are represented for spam detection based on batch learning. In this paper, a new algorithm based on incremental learning is introduced. The algorithm composes new knowledge from new training data with previous knowledge by combining classifiers based on weighted majority voting. The experiment results show that the proposed algorithm outperforms other related incremental algorithms and non-incremental algorithms
Nondetection zone assessment of an active islanding detection method and its experimental evaluation, Article IEEE Transactions on Power Delivery ; Volume 26, Issue 2 , 2011 , Pages 517-525 ; 08858977 (ISSN) ; Karimi, H ; Iravani, R ; Sharif University of Technology
This paper analytically determines the nondetection zone (NDZ) of an active islanding detection method, and proposes a solution to obviate the NDZ. The method actively injects a negative-sequence current through the interface voltage-sourced converter (VSC) of a distributed generation (DG) unit, as a disturbance signal for islanding detection. The estimated magnitude of the corresponding negative-sequence voltage at the PCC is used as the islanding detection signal. In this paper, based on a laboratory test system, the performance of the islanding detection method under UL1741 anti-islanding test conditions is evaluated. Then, determining the NDZ of the method and proposing the...
Article Proceedings - 2015 2nd International Conference on Biomedical Engineering, ICoBE 2015 ; 2015 ; 9781479917495 (ISBN) ; 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...
Article Final Program and Abstract Book - 4th International Symposium on Communications, Control, and Signal Processing, ISCCSP 2010, 3 March 2010 through 5 March 2010 ; March , 2010 ; 9781424462858 (ISBN) ; Mousavi, S. R ; Vosoughi Vahdat, B ; Shamsollahi, M. B ; Sayyah, M ; Sharif University of Technology
Epileptic seizures are generated by an abnormal synchronization of neurons. Since epileptic seizures are unforeseeable for the patients, epileptic seizures detection is an interesting issue in epileptology, that novel approaches to understand the mechanism of epileptic seizures. In this study we analyzed invasive electroencephalogram (EEG) recordings in patients suffering from medically intractable focal epilepsy with a nonlinear method called, dissimilarity index. In order to detect epileptic seizures Bhattacharyya distance between trajectory matrix of reference window during an interval quite distant in time from any seizure and trajectory matrix of present window is employed to measure...
Article IET Signal Processing ; Volume 10, Issue 1 , 2016 , Pages 55-62 ; 17519675 (ISSN) ; Ahmadi, P ; Sadeghi, M ; Rahnavard, N ; Sharif University of Technology
Institution of Engineering and Technology
The problem of signal detection using a flexible and general model is considered. Owing to applicability and flexibility of sparse signal representation and approximation, it has attracted a lot of attention in many signal processing areas. In this study, the authors propose a new detection method based on sparse decomposition in a union of subspaces model. Their proposed detector uses a dictionary that can be interpreted as a bank of matched subspaces. This improves the performance of signal detection, as it is a generalisation for detectors. Low-rank assumption for the desired signals implies that the representations of these signals in terms of some proper bases would be sparse. Their...
Article International Journal of Communication Systems ; Volume 30, Issue 1 , 2017 ; 10745351 (ISSN) ; Jahangir, A. H ; Sharif University of Technology
John Wiley and Sons Ltd 2017
In this paper, we study the effects of anomalies on the distribution of TCP flow interarrival time process. We show empirically that despite the variety of data networks in size, number of users, applications, and load, the interarrival times of normal flows comply with the Weibull distribution, whereas specific irregularities (anomalies) causes deviations from the distribution. We first estimate the scale and shape parameters and then check the discrepancy of the data from a Weibull distribution with the estimated parameters. We also utilize the Weibull counting model to recheck the conformance of small flow interarrival times with the distribution. We perform our experiments on a diverse...
Landmark extraction from echocardiography sequence based on corner detection algorithms using product moment coefficient matcher, Article 2009 International Conference on Signal Processing Systems, ICSPS 2009, Singapore, 15 May 2009 through 17 May 2009 ; 2009 , Pages 91-97 ; 9780769536545 (ISBN) ; Behnam, H ; Fatemi Zadeh, E ; Sharif University of Technology
Landmark extraction is used as the first step of many vision tasks such as tracking, image registration, localization, image matching and recognition. Furthermore, landmarks are used to reduce the data flow and consequently the computational costs. In this paper we extracted landmarks from echocardiography sequence, our algorithm is based on corner extraction, and then we evaluate our algorithm with applying some test. For this purpose, we evaluated the detectors according to their repeatability, stability and landmark localization under changes in noise. © 2009 IEEE
Article IET International Radar Conference 2009, Guilin, 20 April 2009 through 22 April 2009 ; Issue 551 CP , 2009 ; 9781849190107 (ISBN) ; Mirzaei, S ; Norouzi, Y ; Sharif University of Technology
In many radar and EW applications, after some processing, the envelope of the received pulse is calculated and is used for target detection. Most of the time only the effect of thermal noise is considered in such detectors, but in most of the practical applications, before envelope detection, the signal should be down converted from radio frequency (RF) to an intermediate frequency (IF). In this case, the phase noise of the local oscillator will affect the signal, too. Surprisingly, in contrast to thermal noise, the effect of phase noise on the envelope of signal becomes more considerable whenever the IF bandwidth is decreased. So there exists an optimum IF bandwidth for the receiver. In...