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Total 22 records

    Sensor placement in AOA localization of multiple sources in the presence of distance dependent noise

    , Article 27th Iranian Conference on Electrical Engineering, ICEE 2019, 30 April 2019 through 2 May 2019 ; 2019 , Pages 1233-1238 ; 9781728115085 (ISBN) Solhi Juybari, S. M ; Hamdollahzadeh, M ; Behnia, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    In this paper, we consider the problem of sensor placement for passive source localization under conditions where there are multiple sources and noise measurement is distance dependent. To this end, first we derive the Cramer-Rao bound for the angle of arrival (AOA) based source localization for distance-dependent noise model and existence of multiple sources. Then, the optimal arrangement of sensors to achieve this bound is obtained  

    Optimal sensor placement for source localization in nlos conditions

    , Article 26th Iranian Conference on Electrical Engineering, ICEE 2018, 8 May 2018 through 10 May 2018 ; 2018 , Pages 435-439 ; 9781538649169 (ISBN) Juybari, S. M. S ; Behnia, F ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    The problem of sensor placement for passive source localization under the non-line of sight signal propagation is considered in this paper. To this end, first we derive the Cramer-Rao lower bound for the time of arrival based source localization under non-line of sight conditions. Then, the optimal arrangement of sensors to achieve this lower bound is obtained in the two important cases with all of the receivers being non line of sight ones in the first case and a combination of line of sight and non-line of sight receivers in the 2nd case. © 2018 IEEE  

    Complexity Reduction in AoA Estimation with root-MUSIC

    , M.Sc. Thesis Sharif University of Technology Eskandari, Meysam (Author) ; Bastani, Mohammad Hassan (Supervisor) ; Karbasi, Mohammad (Co-Supervisor)
    Abstract
    Localization of radio sources has various applications in civil and military communications. Some of important localization methods consist of Angle of Arrival (AoA) estimation of the illuminated signals from the interested sources. Between various Direction Finding (DF) methods, subspace based methods are of special importance, because of their high resolution and accuracy. And from beginning of invention, because of new challenges, have been focus of numerous researches. In this thesis, first we explain the most important subspace based DF methods called MUSIC and root-MUSIC. Then a novel modification for root-MUSIC is introduced. In our new method the computational complexity of... 

    Canonical polyadic decomposition of complex-valued multi-way arrays based on simultaneous schur decomposition

    , Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings ; 2013 , Pages 4178-4182 ; 15206149 (ISSN) ; 9781479903566 (ISBN) Sardouie, S. H ; Albera, L ; Shamsollahi, M. B ; Merlet, I ; Sharif University of Technology
    2013
    Abstract
    In this paper, we propose a new semi-algebraic algorithm to compute the Canonical Polyadic (CP) decomposition of complex-valued multi-way arrays. The proposed algorithm is based on the Simultaneous Schur Decomposition (SSD) of particular matrices derived from the array to process. This CP algorithm solves some convergence problems of classical iterative techniques and its identifiability assumptions are less restrictive than those of other semi-algebraic methods. We also propose a new Jacobi-like algorithm to calculate the SSD of several complex-valued matrices. Finally the usefulness of the proposed method is illustrated in the context of fluorescence spectroscopy and epileptic source... 

    Estimation of effective brain connectivity with dual kalman filter and EEG source localization methods

    , Article Australasian Physical and Engineering Sciences in Medicine ; Volume 40, Issue 3 , 2017 , Pages 675-686 ; 01589938 (ISSN) Rajabioun, M ; Motie Nasrabadi, A ; Shamsollahi, M. B ; Sharif University of Technology
    Abstract
    Effective connectivity is one of the most important considerations in brain functional mapping via EEG. It demonstrates the effects of a particular active brain region on others. In this paper, a new method is proposed which is based on dual Kalman filter. In this method, firstly by using a brain active localization method (standardized low resolution brain electromagnetic tomography) and applying it to EEG signal, active regions are extracted, and appropriate time model (multivariate autoregressive model) is fitted to extracted brain active sources for evaluating the activity and time dependence between sources. Then, dual Kalman filter is used to estimate model parameters or effective... 

    EEG Brain Functional Network Analysis in Cortex Level

    , M.Sc. Thesis Sharif University of Technology Pedrood, Bahman (Author) ; Jalili, Mahdi (Supervisor)
    Abstract
    Complex networks science have received tremendous attention in recent years and the brain is one of the systems to which graph theoretical tools have been applied. Alzheimer’s disease (AD) is a neurodegenerative disease affecting many of elderly population. AD changes the anatomy of the brain, which subsequently results in changes in its functions. These changes have been frequently reported in signals recorded from the brain (such as MEG, fMRI and EEG). Among these neuroimaging techniques EEG is one of the most aproprate methods for extracting functional connectivites according to high temporal resolution. In this thesis, we aimed at analyzing the properties of EEG-based functional networks... 

    Implementation of Outdoor Sound Source Localization System Using Sound Sensor Arrays

    , M.Sc. Thesis Sharif University of Technology Fathi, Ehsan (Author) ; Gholampour, Eman (Supervisor) ; Sharif Khani, Mohammad (Supervisor)
    Abstract
    Sound source localization has been one of the fundamental problems in many areas, including radar, teleconferencing or videoconferencing, localization of earthquake epicenters and underground explosions, microphone arrays, robots, etc. All of sound source localization ideas are like human auditory system. The human auditory system is a complex and organic information processing system. It can feel the intensity and spatial orientation and other information of sound. The distance of the two ears on our head is about 20cm. When the sound reaches each ear, there are small time difference, intensity difference and phase difference. After analyzing these differences by the brain, the human can... 

    Human-Robot Interaction through Sound Source Localization for “Arash” Social Robot

    , M.Sc. Thesis Sharif University of Technology Eydi, Abdollah (Author) ; Meghdari, Ali (Supervisor) ; Vossoughi, Gholamreza ($item.subfieldsMap.e) ; Alemi, Minoo ($item.subfieldsMap.e)
    Abstract
    Over the years, The robots have entered the human community in addition to the factories and industrial centers, and a new branch in the field of robotics called social robots has been created. Such robots can become a personal companion for children and elderly people who accompany that person at home or outside. Social robots can even be used as a platform for health services or as a vendor in stores. The interaction of humans and robots in social robots and communicating with the audience is the main part of this series of robots. Human-robot interaction can be divided into three parts: visual, auditory and facial or body movements. Also, the behavior of a social robot must be as natural... 

    Diagnosis of early Alzheimer's disease based on EEG source localization and a standardized realistic head model

    , Article IEEE Journal of Biomedical and Health Informatics ; Volume 17, Issue 6 , 2013 , Pages 1039-1045 ; 21682194 (ISSN) Aghajani, H ; Zahedi, E ; Jalili, M ; Keikhosravi, A ; Vahdat, B. V ; Sharif University of Technology
    2013
    Abstract
    In this paper, distributed electroencephalographic (EEG) sources in the brain have been mapped with the objective of early diagnosis of Alzheimer's disease (AD). To this end, records from a montage of a high-density EEG from 17 early AD patients and 17 matched healthy control subjects were considered. Subjects were in eyes-closed, resting-state condition. Cortical EEG sources were modeled by the standardized low-resolution brain electromagnetic tomography (sLORETA) method. Relative logarithmic power spectral density values were obtained in the four conventional frequency bands (alpha, beta, delta, and theta) and 12 cortical regions. Results show that in the left brain hemisphere, the theta... 

    Effective brain connectivity estimation between active brain regions in autism using the dual Kalman-based method

    , Article Biomedizinische Technik ; Volume 65, Issue 1 , 2020 , Pages 23-32 Rajabioun, M ; Motie Nasrabadi, A ; Shamsollahi, M. B ; Coben, R ; Sharif University of Technology
    De Gruyter  2020
    Abstract
    Brain connectivity estimation is a useful method to study brain functions and diagnose neuroscience disorders. Effective connectivity is a subdivision of brain connectivity which discusses the causal relationship between different parts of the brain. In this study, a dual Kalman-based method is used for effective connectivity estimation. Because of connectivity changes in autism, the method is applied to autistic signals for effective connectivity estimation. For method validation, the dual Kalman based method is compared with other connectivity estimation methods by estimation error and the dual Kalman-based method gives acceptable results with less estimation errors. Then, connectivities... 

    Analysis, Design and Implementation of a Low Power and High Speed Sound Source Localizer

    , M.Sc. Thesis Sharif University of Technology Zarghi, Hamid Reza (Author) ; Sharif Khani, Mohammad (Supervisor) ; Gholampour, Iman (Supervisor)
    Abstract
    Throughout localization algorithms, sound source localization has received much interest using microphone array. Applications like tracking and determining angle of acoustic signal arrival have been combined with array processing techniques in the previous decade. Distributed micro sensor array have been suggested for a wide range of nowaday’s localization algorithms. The major goals are monitoring the environment, distinction, and pursue some phenomenon. This type of networks can be utilized for military application in tracking acoustic sources. Today’s advancement in technology allows implementation of the ultra low cost and low power integrated circuit for such application in the form of... 

    Alzheimer's Disease Diagnosis Using Brain Source Localiztion, Based on Realistic Head Model

    , M.Sc. Thesis Sharif University of Technology Aghajani, Haleh (Author) ; Vosoughi Vahdat, Bijan (Supervisor) ; Jalili, Mahdi (Co-Advisor)
    Abstract
    Dementia is one of the most common disorders among the elderly population. Statistical analyses show that among several subtypes of dementia, Alzheimer’s disease (AD) is the most frequent cause of dementia and this number is projected to increase. AD not only results in impairment of learning and memory but also in the moderate stages of illness, motor functions are profoundly disturbed, and ultimately will affect the patient's lifetime. The proposed drug treatments for this disease only reduce its progress probability. Therefore, early diagnosis for effective treatment of Alzheimer's disease is one of the critical issues in the field of dementia. This project is an effort to extract... 

    Source Localization of EEG in Early Alzheimer’s Disease

    , M.Sc. Thesis Sharif University of Technology Salami, Mohsen (Author) ; Manzuri Shalmani, Mohammad Taghi (Supervisor)
    Abstract
    Localization of electrical activity in the brain is one of the major problems in cognitive science and neuroscience. Indeed, Source localization is the inverse processing procedure on brain signals to estimate the location and position of resources in the human brain. Current technics for neurological imaging is included fMRI، PET، MEG and ERP. These methods is not appropriated to answer the question that when does each of different components of the brain begin their activity. The EEG signals could be useful to eliminate some of limitations of above methods. The problem with EEG signals collected from the skull is that they don’t refer directly to the location of active neurons. The... 

    Fusion of Audio and Visual Occurrences using Fuzzy Logic for Improving Perception Quality of Events

    , Ph.D. Dissertation Sharif University of Technology Faraji, Mohammad Mahdi (Author) ; Bagheri Shouraki, Saeed (Supervisor)
    Abstract
    The ability of human to analyze the environment around them has been an inspiring source for event analysis research. Since human perception of the environment is formed in a multi-modal space, many efforts have been made to fuse information to create an intelligent fusion. In this study, we want to better understand the environment using information fusion. For this purpose, fuzzy fusion of audio and video signals based on ink drop spread operator is performed for recognizing and tracking of the targets using several scenarios of the AV16.3 dataset. We then focused on the fusion of audio data for sound source localization, one of the most important applications in evaluating fusion... 

    Constrained optimization of sensors trajectories for moving source localization using TDOA and FDOA measurements

    , Article International Conference on Robotics and Mechatronics, ICROM 2015, 7 October 2015 through 9 October 2015 ; 2015 , Pages 200-204 ; 9781467372343 (ISBN) Adelipour, S ; Hamdollahzadeh, M ; Behnia, F ; Sharif University of Technology
    2015
    Abstract
    This paper examines the problem of determining optimal sensors trajectories for localization of a moving radio source based on Time Difference of Arrival (TDOA) and Frequency Difference of Arrival (FDOA) measurements in situations in which sensors are constrained both in their movements and regions of operation. By considering the movement of the source and constrained movement of the sensors, a constraint problem is formed which is solved to determine optimal trajectories of the sensors for source tracking. The validity of the proposed algorithm is assessed by two different simulation scenarios and the results verify its proper operation with estimation error decreasing in consecutive steps... 

    Optimal sensor configuration for two dimensional source localization based on TDOA/FDOA measurements

    , Article Proceedings International Radar Symposium, 10 May 2016 through 12 May 2016 ; Volume 2016-June , 2016 ; 21555753 (ISSN) ; 9781509025183 (ISBN) Hamdollahzadeh, M ; Adelipour, S ; Behnia, F ; Sharif University of Technology
    IEEE Computer Society  2016
    Abstract
    The Cramer-Rao lower bound for source localization based on Time Difference of Arrival and Frequency Difference of Arrival is investigated in this paper. The result is used for theoretical analysis of optimality in sensor placement. An optimal sensor-target geometry including sensors locations and velocities is presented and its properties is studied  

    Sound source localization in wide-range outdoor environment using distributed sensor network

    , Article IEEE Sensors Journal ; Volume 20, Issue 4 , 2020 , Pages 2234-2246 Faraji, M. M ; Shouraki, S. B ; Iranmehr, E ; Linares Barranco, B ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    Sound source localization has always been one of the most challenging subjects in different fields of engineering, one of the most important of which being tracking of flying objects. This article focuses on sound source localization using fuzzy fusion and a beamforming method. It proposes a new fuzzy-based algorithm for localizing a sound source using distributed sensor nodes. Eight low-cost sensor nodes have been constructed in this study each of which consists of a microphone array to capture sound waves. Each node is able to record audio signals synchronously on an SD card to evaluate different algorithms offline. However, the sensor nodes are designed to be able to estimate the location... 

    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
    2012
    Abstract
    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... 

    Source localization through adaptive signal attenuation model and time delay estimation

    , Article 2011 18th International Conference on Telecommunications, ICT 2011 ; 2011 , Pages 151-156 ; 9781457700248 (ISBN) Aghasi, H ; Hashemi, M ; Khalaj, B. H ; IBM Cyprus; University of Cyprus; Cyprus Tourism Organisation ; Sharif University of Technology
    Abstract
    In this paper we present a method of localizing multiple wideband acoustic sources based on both signal attenuation pattern and delays in the reception of the signal. Moreover, an additional order of flexibility is added to the problem by considering the attenuation model as an unknown function with reasonable prior assumptions about its functional space. Such approach is capable of enhancing the localization performance compared to when only the signal attenuation data or the time delays are used. A cost function is then formed in terms of the sources locations and the attenuation model parameters. Having different types of unknowns in the cost function, convergence concerns, and the... 

    Fuzzy based algorithm for acoustic source localization using array of microphones

    , Article 2017 25th Iranian Conference on Electrical Engineering, ICEE 2017, 2 May 2017 through 4 May 2017 ; 2017 , Pages 2102-2105 ; 9781509059638 (ISBN) Faraji, M. M ; Bagheri Shouraki, S ; Iranmehr, E ; Sharif University of Technology
    Abstract
    This paper focuses on localizing acoustic source using fuzzy logic. For this purpose, an array of microphones are used as sensors. The Time Delay Estimation (TDE) is performed by correlation between received signals from each pair of microphones. In this paper, instead of assuming a crisp value as a TDOA, we introduce fuzzy number of TDOA in which the absolute value of the cross correlation function is normalized and then assumed as TDOA membership function for each pair of microphones. Truth value of presenting acoustic source is computed in region of interest based on achieved TDOA membership functions. Computing this truth value is represented in this paper based on fuzzy logic. The...