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Fast block-sparse decomposition based on SL0
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 27 September 2010 through 30 September 2010 ; Volume 6365 LNCS , September , 2010 , Pages 426-433 ; 03029743 (ISSN) ; 9783642159947 (ISBN) ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
2010
Abstract
In this paper we present a new algorithm based on Smoothed ℓ0 (SL0), called Block SL0 (BSL0), for Under-determined Systems of Linear Equations (USLE) in which the nonzero elements of the unknown vector occur in clusters. Contrary to the previous algorithms such as Block Orthogonal Matching Pursuit (BOMP) and mixed ℓ2/ℓ1 norm, our approach provides a fast algorithm, while providing the same (or better) accuracy. Moreover, we will see experimentally that BSL0 has better performance than SL0, BOMP and mixed ℓ2/ℓ1 norm when the number of nonzero elements of the source vector approaches the upper bound of uniqueness theorem
Application of Sparse Decomposition to Optical Character Recognition
, M.Sc. Thesis Sharif University of Technology ; Babaie-Zadeh, Massoud (Supervisor)
Abstract
Optical Character Recognition is a branch of Image Processing and deals with transforming a scanned document into a text file. The output of a scanning system is in image format and a digital system has no sense about its content. Therefore, this system cannot do any process on its text. For example, words searching, sentences edition and another tasks that are easily done in a word processing software, cannot be directly applied on a scanned document. So, we need a tool to extract the text from a scanned document. A character recognition system consists of different stages: scanning, preprocessing, segmentation, feature extraction, character recognition and post-processing. The purpose of...
Corrigendum to "ISI sparse channel estimation based on SL0 and its application in ML sequence-by-sequence equalization" [Signal Processing 92 (2012) 1875-1885] (DOI:10.1016/j.sigpro.2011.09.035)
, Article Signal Processing ; 2013 ; 01651684 (ISSN) ; Hamidi Ghalehjegh, S ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
2013
Abstract
In this paper, which is an extended version of our work at LVA/ICA 2010 [1], the problem of Inter Symbol Interface (ISI) Sparse channel estimation and equalization will be investigated. We firstly propose an adaptive method based on the idea of Least Mean Square (LMS) algorithm and the concept of smoothed l0 (SL0) norm presented in [2] for estimation of sparse ISI channels. Afterwards, a new non-adaptive fast channel estimation method based on SL0 sparse signal representation is proposed. ISI channel estimation will have a direct effect on the performance of the ISI equalizer at the receiver. So, in this paper we investigate this effect in the case of optimal Maximum Likelihood...
Adaptive and non-adaptive ISI sparse channel estimation based on SL0 and its application in ML sequence-by-sequence equalization
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 27 September 2010 through 30 September 2010 ; Volume 6365 LNCS , September , 2010 , Pages 579-587 ; 03029743 (ISSN) ; 9783642159947 (ISBN) ; Hamidi Ghalehjegh, S ; Babaie Zadeh, M ; Jutten, C ; Sharif University of Technology
2010
Abstract
In this paper, we firstly propose an adaptive method based on the idea of Least Mean Square (LMS) algorithm and the concept of smoothed l 0 (SL0) norm presented in [1] for estimation of sparse Inter Symbol Interface (ISI) channels which will appear in wireless and acoustic underwater transmissions. Afterwards, a new non-adaptive fast channel estimation method based on SL0 sparse signal representation is proposed. ISI channel estimation will have a direct effect on the performance of the ISI equalizer at the receiver. So, in this paper we investigate this effect in the case of optimal Maximum Likelihood Sequence-by-sequence Equalizer (MLSE) [2]. In order to implement this equalizer, we...
Design and implementation of a new body weight support (BWS) system
, Article 5th RSI International Conference on Robotics and Mechatronics, IcRoM 2017, 25 October 2017 through 27 October 2017 ; 2018 , Pages 69-75 ; 9781538657034 (ISBN) ; Behzadipour, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Gait training is a critical rehabilitation procedure for patients suffering from walking problems. It, however, puts the therapist in high orthopedic risk since he should prevent the patient from possible falling. Body weight support system is a new technology helping such patients and the involved therapist by unloading a percent of the patient's weight. A new over-ground body weight support is introduced in this article. The system is composed of two main modules namely unloading and traction. The unloading module is capable of suspending an individual's weight up to 1000N dynamically. The whole system is attached to an overhead rail, moving over the head of the patient by the traction...
Critical state concepts for a cemented gravely sand
, Article Electronic Journal of Geotechnical Engineering ; Volume 10 E , 2005 ; 10893032 (ISSN) ; Haeri, S. M ; Sharif University of Technology
2005
Abstract
The shear behavior of a cemented gravely sand that can be considered as the representative of Tehran alluvium has been studied using triaxial equipment. Artificially cemented samples were prepared using gypsum plaster as the cementing agent. The plaster was mixed with the base soil at the weight percentages between 1.5 and 6. The critical state concepts were used to illustrate the mechanical behavior of tested soil. © 2005 ejge
Block adaptive compressive sensing for distributed MIMO radars in clutter environment
, Article Proceedings International Radar Symposium, 10 May 2016 through 12 May 2016 ; Volume 2016-June , 2016 ; 21555753 (ISSN) ; 9781509025183 (ISBN) ; Mohajer Hamidi, S ; Marvasti, F ; Sharif University of Technology
IEEE Computer Society
2016
Abstract
For the target parameter estimation in MIMO radars in the presence of strong clutter, non-adaptive compressive sensing methods have a poor performance. On the other hand, the adaptive ones usually need higher data acquisition time. In this paper, we propose an adaptive compressive sensing method called L-BGT that has tolerable data acquisition time. furthermore, we have presented the essential changes in a distributed MIMO radar to exploit an adaptive group testing compressive sensing method
Uncertainty analysis of wind-wave predictions in Lake Michigan
, Article China Ocean Engineering ; Volume 30, Issue 5 , 2016 , Pages 811-820 ; 08905487 (ISSN) ; Ataie Ashtiani, B ; Hamidi, S. A ; Sharif University of Technology
Springer Verlag
2016
Abstract
With all the improvement in wave and hydrodynamics numerical models, the question rises in our mind that how the accuracy of the forcing functions and their input can affect the results. In this paper, a commonly used numerical third-generation wave model, SWAN is applied to predict waves in Lake Michigan. Wind data are analyzed to determine wind variation frequency over Lake Michigan. Wave predictions uncertainty due to wind local effects are compared during a period where wind has a fairly constant speed and direction over the northern and southern basins. The study shows that despite model calibration in Lake Michigan area, the model deficiency arises from ignoring wind effects in small...
On new nonlinearity in third-order elastic modulus for vibrational analysis of FG porous beam based on nonlocal strain gradient and surface energy by modified homotopy perturbation method
, Article European Physical Journal Plus ; Volume 137, Issue 4 , 2022 ; 21905444 (ISSN) ; Alizadeh Hamidi, B ; Maboudi, G ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
In the current study, by considering both material and geometry nonlinearity, the nonlinear free vibration of functionally graded porous nanobeams based on the nonlocal strain gradient theory is investigated. Generally, the third-order elastic modulus, von Karman strain–displacement relationship, is assumed to incorporate the nonlinearity into the differential equation of the problem. In this paper, for the first time, the nonlinear vibrational response of the nanobeam does not merely depend on the geometric nonlinearity. Also, material nonlinearity of the bulk and surface layers is taken into consideration. Governing equations and the related boundary conditions are obtained by utilizing...
Non-fragile control and synchronization of a new fractional order chaotic system
, Article Applied Mathematics and Computation ; Volume 222 , 2013 , Pages 712-721 ; 00963003 (ISSN) ; Delshad, S. S ; Hamidi Beheshti, M. T ; Tavazoei, M. S ; Sharif University of Technology
2013
Abstract
In this paper, we address global non-fragile control and synchronization of a new fractional order chaotic system. First we inspect the chaotic behavior of the fractional order system under study and also find the lowest order (2.49) for the introduced dynamics to remain chaotic. Then, a necessary and sufficient condition which can be easily extended to other fractional-order systems is proposed in terms of Linear Matrix Inequality (LMI) to check whether the candidate state feedback controller with parameter uncertainty can guarantee zero convergence of error or not. In addition, the proposed method provides a global zero attraction of error that guarantees stability around all existing...
Generation of motional entangled coherent state in an optomechanical system in the single photon strong coupling regime
, Article Journal of Modern Optics ; Volume 62, Issue 19 , Jul , 2015 , Pages 1685-1691 ; 09500340 (ISSN) ; Shakeri, S ; Hamidi, O ; Zandi, M. H ; Bahrampour, A ; Sharif University of Technology
Taylor and Francis Ltd
2015
Abstract
The single-photon strong coupling in the deep-resolved sideband of the optomechanical system induces photon blockade (PB) effect. For the PB cavity, an initial mechanical coherent state evolves into superposition of phonon cat states entangled with the cavity Fock states. Measurement of the cavity photon number states produces phonon even and odd cat states. The information leakage effect of two photon states on the fidelity of cat states is calculated, it is shown that for low average phonon number this effect is negligible and decreases by increasing the two photon cavity state. The Lindblad equation is solved numerically to obtain the environmental effects on the fidelity of cat states
Hydrogen storage in single- and multi-walled carbon nanotubes and nanotube bundles
, Article Australian Journal of Basic and Applied Sciences ; Volume 5, Issue 7 , 2011 , Pages 483-490 ; 19918178 (ISSN) ; Golnabi, H ; Sharif University of Technology
2011
Abstract
This article describes the hydrogen storage capacity in different carbon nanotubes. The hydrogen storage capacities in the armchair, zigzag, and chiral nanotubes are investigated. The hydrogen storing capacities as a function of the carbon nanotube (CNT) diameter are investigated for the single-walled (SWNT), multi-walled (MWNT), and CNT bundles and results are compared. Hydrogen storage capacity in SWNTs is increased by increasing the nanotube diameter. For diameter d=0.3887 nm of (5,0) CNT the hydrogen capacity is 0.99%, while for the (17,17) SWNT with a diameter d=2.289 nm the capacity is increased to 5.06%. In comparison of different MWNTs for a common external diameter d=1.6064 nm the...
The effect of filler type and content on rutting resistance of asphaltic materials
, Article International Journal of Pavement Research and Technology ; Volume 12, Issue 3 , 2019 , Pages 249-258 ; 19966814 (ISSN) ; Motamed, A ; Sharif University of Technology
Springer
2019
Abstract
This research evaluates the effect of filler type and content on rutting resistance of asphaltic materials by using laboratory experiments. To examine the effect of filler type, two traditional fillers (Silica sandstone powder and Portland cement) and a new recycled lime powder (Eggshell) were considered. To investigate the effect of filler content, three different filler contents were used. Marshall Stability test was performed on full mixes in order to determine the optimum binder content of the mixtures. Then, the static creep test was performed on Fine Aggregate Matrix (FAM) samples. The permanent strain after 10 minutes of recovery (PS-660) was considered as the indicator of potential...
An Investigation on the Effect of Filler Type and Content on the Performance of Asphaltic Materials
, M.Sc. Thesis Sharif University of Technology ; Motamed, Arash (Supervisor)
Abstract
The objective of this research is evaluating the effect of filler type and content on the characteristics of asphaltic materials. The properties of the asphalt mixture are greatly influenced by its components. As asphalt mixtures are composed of two prominent components, aggregates and binder, the change in type and contents of these materials may lead to altering the performance of asphalt mixtures. Aggregates in the asphalt mixtures are categorized into three groups based on their particle sizes: coarse aggregate, fine aggregate and mineral filler. The effect of filler on the characteristics of asphalt mixtures can be examined by changing the type and content of filler and holding the...
Design and Construction of an Economic System Based on the Internet of Things (IoT) for Monitoring the Performance of Light Vessels
, M.Sc. Thesis Sharif University of Technology ; Khorasanchi, Mahdi (Supervisor)
Abstract
Having a large source and volume of data from various machinery and electronic devices, as well as the aggregation and diverse uses of this data for higher productivity, greater safety, increased reliability, and ultimately higher profits, is a necessity and demand in every industry. This is especially important in the maritime and shipping transportation sector. The solution to predicting and preventing wear, failure, and ultimately the breakdown of vessels is to have data that is continuously and automatically collected from the ship, with the capability for transmission and analysis. The goal of this project is to develop a cost-effective system for monitoring lightweight vessels, which,...
Robust outer synchronization between two complex networks with fractional order dynamics
, Article Chaos ; Volume 21, Issue 3 , 2011 ; 10541500 (ISSN) ; Míguez, J ; Hamidi Beheshti, M. T ; Tavazoei, M. S ; Sharif University of Technology
2011
Abstract
Synchronization between two coupled complex networks with fractional-order dynamics, hereafter referred to as outer synchronization, is investigated in this work. In particular, we consider two systems consisting of interconnected nodes. The state variables of each node evolve with time according to a set of (possibly nonlinear and chaotic) fractional-order differential equations. One of the networks plays the role of a master system and drives the second network by way of an open-plus-closed-loop (OPCL) scheme. Starting from a simple analysis of the synchronization error and a basic lemma on the eigenvalues of matrices resulting from Kronecker products, we establish various sets of...
Risk analysis of liquefaction potential in South West Tehran
, Article Amirkabir (Journal of Science and Technology) ; Volume 15, Issue 58 D , 2004 , Pages 521-534 ; 10150951 (ISSN) ; Haeri, S. M ; Shirazi, A ; Olyaei, M. N ; Bakhshi, A ; Sharif University of Technology
2004
An analytical model for evaluation of wireless mesh networks
, Article 2008 International Symposium on Telecommunications, IST 2008, Tehran, 27 August 2008 through 28 August 2008 ; October , 2008 , Pages 295-300 ; 9781424427512 (ISBN) ; Ashtiani, F ; Sharif University of Technology
2008
Abstract
Wireless mesh networks (WMNs) are well-promising future networks especially for ubiquitous connection to Internet. In this paper, we propose an analytical model in order to evaluate the maximum stable throughput of a WMN based on a simplified version of IEEE 802.11s MAC protocol. Our modeling approach is based on a multi-class open queueing network. In this respect, we map some of the important features of IEEE 802.11s MAC protocol, esp., its contention-based and contention-free periods onto different parameters of the proposed queueing network. By solving the related traffic equations and applying the stability condition, we determine the maximum stable throughput, i.e., the maximum packet...
Thermally expanded graphite: a promising anode electrode in the current and next-generation LIBs
, Article New Journal of Chemistry ; Volume 47, Issue 26 , 2023 , Pages 12085-12088 ; 11440546 (ISSN) ; Askari, K ; Salimi, P ; Sharif University of Technology
Royal Society of Chemistry
2023
Abstract
In this work, a simple synthesis approach is suggested to achieve expanded graphite from natural graphite precursors via thermal treatment. The structural, morphological, and electrochemical properties of TEG show that it is a promising anode electrode for conventional and beyond LIBs. © 2023 The Royal Society of Chemistry
Design of Transmit Code & Receive Filter in Radar Via Manifold Optimization
, M.Sc. Thesis Sharif University of Technology ; Karbasi, Mohammad (Supervisor)
Abstract
The problem of joint design of transmit code and receive filter is considered in many application scenarios of multiple input multiple output (MIMO) radar systems. The performance of the joint design problem is evaluated with the signal-to-interference ratio (SINR) metric in the presence of noise. In such problems, the optimization problem is to maximize SINR on the receiver side with the constraints that are applied on the transmitted waveform. Our proposed method, RTR, is a manifold-based geometric method that performs better than the SDP method in terms of algorithm execution speed and calculation complexity. For simulation, we took sampled and real TIR with Target Aspect Angle (TAA) in a...