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salehi--farnaz
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Quantum Communications with Structured Light
, M.Sc. Thesis Sharif University of Technology ; Bahrampour, Alireza (Supervisor) ; Farman, Farnaz (Co-Supervisor)
Abstract
Orbital angular momentum (OAM)and the radial quantum number (p) in infinite-dimensional Hilbert space are two degrees of freedom of light which are associated with the spatial distribution of the electromagnetic field. They are attracting a growing interest for their potential in communication applications ranging from classical communication to fundamental tests of quantum mechanics,quantum communication and quantum cryptography. However, a third party trying to eavesdrop information from communication channel and treat channel security , quantum cryptography or quantum key distribution (QKD) is the secure communication method which is based on the quantum mechanical principles can...
Angular Momentum Compensation and Sorting of Optical Modes in Optical Fiber
, Ph.D. Dissertation Sharif University of Technology ; Bahrampour, Alireza (Supervisor) ; Farman, Farnaz (Supervisor)
Abstract
Electromagnetic field modes have several degrees of freedom, including polarization, orbital angular momentum, and radial order, which can be described by orthogonal modes. By using all the degrees of freedom in communication, the channel capacity can be increased dramatically. With the aim of increasing the capacity and correcting the errors created along the optical fiber, two important issues have been addressed in this thesis. First, the states propagated in the fiber may be disrupted by many unwanted factors and may not be transmitted correctly. Therefore, measures should be taken to minimize the impact of these factors as much as possible or to compensate for their effects. In the...
Detection of High Frequency Oscillations from ECoG Recordings in Epileptic Patients
, M.Sc. Thesis Sharif University of Technology ; Hajipour, Sepideh (Supervisor) ; Sinaei, Farnaz (Co-Supervisor)
Abstract
The processing of brain signals, including the electrocorticogram (ECoG) signal, is widely used in the investigation of neurological diseases. Conventionally, the ECoG signal has frequency components up to the range of 80 Hz. Studies have proven that in some conditions, such as epilepsy, the brain signal includes frequency components higher than 80 Hz, which are called high-frequency oscillations (HFO). Therefore, HFOs are recognized as a biomarker for epilepsy. The aim of this thesis is to review the previous methods of detecting HFOs and to present new methods with greater efficiency in the direction of diagnosis or treatment of epileptic patients. For this purpose, we used the ECoG data...
Optimizing the Balance Between Resolution, Field-of-View and Depth-of-field in Three-dimensional Imaging
, Ph.D. Dissertation Sharif University of Technology ; Mehrany, Khashayar (Supervisor) ; Bagheri, Saeed (Supervisor) ; Massoumian, Farnaz (Co-Advisor)
Abstract
In this thesis a rigorous approach toward systematic quantification of qualitative fea-tures in a three-dimensional (3D) integral imaging is proposed. Incorporating the concepts of sampling rays and sampling points, the first approach is based on geo-metrical optics and quantifies the lateral and depth resolutions of the system within the field-of-view (FOV) and depth-of-field (DOF). The obtained results are justified through experiments. In the next step, the principals of wave optics are employed to measure the lateral and depth resolutions of the system. To this end, the concept of point-spread function is generalized to three-dimensional imaging systems. Through this systematic approach the...
Emerging OCDMA communication systems and data networks [electronic resource]
, Article Journal of Optical Networking ; Volume 6, Issue 9, 1 September 2007, Pages 1138-1178 ; Sharif University Of Technology
Abstract
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...
Electroplating and characterization of Cr–Al2O3 nanocomposite film from a trivalent chromium bath [electronic resource]
, Article Anti-Corrosion Methods and Materials ; Vol 61, No 4, 2014, 205-214 ; Sadrnezhaad, Khatiboleslam ; Salehi Doolabi, Davood ; Sharif University of Technology
Abstract
The main aim of this study was to improve current efficiency and to obtain thicker coatings via aluminum oxide (Al2O3) addition to the chromium (Cr) (III) bath. Design/methodology/approach ‐ Pure Cr and nanocomposite Cr–Al2O3 coatings were electrodeposited from Cr (III) bath onto cathode copper substrates by conventional method. Dependence of current efficiency to current density, Al2O3 content and particle size were investigated. Findings ‐ Current efficiency increased with Al2O3 amount and decreased with Al2O3 particle size. Maximum current efficiency was achieved at 25 A/dm2 for pure Cr and 30 A/dm2 for composite coatings. Al2O3 bath content, current density and stirring rate increased...
Spatial heterodyning optical CDMA technique for near-field free-space optical communication systems [electronic resource]
, Article IEEE Journal of Optical Communications and Networking ; Vol. 1, No. 5, PP. 498-511, Oct. 2009 ; Salehi, J. A ; Sharif University Of TechnologyAn automated simple algorithm for realistic pore network extraction from micro-tomography images
, Article Journal of Petroleum Science and Engineering ; Vol. 123, issue , 2014 , pp. 164-171 ; ISSN: 09204105 ; Jamshidi, S ; Salehi, S
2014
Abstract
Using 3-D scanned data to analyze and extract pore network plays a vital role in investigation of porous media's characteristics. In this paper, a new simple method is developed to detect pores and throats for analyzing the connectivity and permeability of the network. This automated method utilizes some of the common and well-known image processing functions which are widely accessible by researchers and this has led to an easy algorithm implementation. In this method, after polishing and quality control of images, using city-block distance function and watershed segmentation algorithm, pores and throats are detected and 3-D network is produced. This method can also be applied on 2-D images...
Essentials of sla for l2 teachers: A transdisciplinary framework, joan kelly hall, routledge, New york
, Article Iranian Journal of Language Teaching Research ; Issue 1 , 2020 , Pages 154-156 ; Sharif University of Technology
Urmia University
2020
Influence of pulse parameters on electrocodeposition of Cr-Al2O3 nanocomposite coatings from trivalent chromium bath
, Article International Heat Treatment and Surface Engineering ; Volume 6, Issue 4 , December , 2012 , Pages 178-184 ; 17495148 (ISSN) ; Sadrnezhaad, S. K ; Salehi Doolabi, D ; Asadirad, M ; Sharif University of Technology
2012
Abstract
Cr and Cr-Al2O3 coatings were electrodeposited from Cr(III) bath with both pulsating and direct current onto copper substrates. Pulsating current resulted in homogeneous films of higher Al2O3 content and lower particle agglomeration than the direct current. Differences were more tangible at shorter duty cycles and pulse frequencies. Pulsating current improved both microhardness and corrosion resistance. The presence of alumina nanoparticles resulted in greater current efficiency, higher film microhardness and better corrosion resistance. Maximum current efficiency, highest microhardness and densest electrodeposited coatings were achieved at current density of 20 A dm-2, duty cycle of 40% and...
Optimum receiver design for transmitted-reference signaling [electronic resource]
, Article IEEE Transactions on Communications ; May 2010, Volume 58, Issue 5, P.1589-1598 ; Salehi, J. A ; Sharif University of Technology
Abstract
Autocorrelation receiver (AcR) is usually used as the general receiver for transmitted reference (TR) communication systems on a quite intuitive basis. In this paper, we apply the principle of statistical invariance to obtain the optimum TR receiver on a decision-theoretic basis, and it is shown that the autocorrelation receiver is optimal only in a special case. Performance of the optimum receiver and the suboptimum AcR for some important modulation schemes is also evaluated. The results imply that allocating a part of the transmitted energy and bandwidth to reference pulses would not help improve the performance of the system and the optimal performance might be achieved via much simpler...
Multi-rate and multi-quality of service passive optical network based on hybrid WDM/OCDM system [electronic resource]
, Article IEEE Communications Magazine ; February 2011, Volume 49, Issue 2, PP. S39-S44 ; Salehi, J. A ; Sharif University of Technology
Abstract
In this article we present a new scheme to support multirate and multi-quality-of-service transmission in passive optical networks based on a hybrid wavelength-division multiplexing/optical code-division multiplexing scheme. The idea is to use multilength variable-weight optical orthogonal codes as signature sequences of a hybrid WDM/OCDM system. To provide the requested classes of service, the code weight and code length of MLVW-OOCs are designed based on the characteristics of the requested classes of service. In order to mitigate multiple access interference, we propose to utilize a multilevel signaling technique and interference remover structure based on advanced optical logic gate...
Emerging OCDMA communication systems and data networks [Invited]
, Article Journal of Optical Networking ; Volume 6, Issue 9 , 2007 , Pages 1138-1178 ; 15365379 (ISSN) ; Sharif University of Technology
Optical Society of American (OSA)
2007
Abstract
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...
Performance of three-level spectrally encoded spreadtime CDMA in the presence of multiple interferences [electronic resource]
, Article IET Communications ; July 2011, Volume 5, Issue 10, P. 1328-1335 ; Mashhadi, Saeed ; Salehi, J. A ; Sharif University of Technology
Abstract
In this study the authors present an in-depth study, analysis and discussion on maximum likelihood (ML)-based receiver for a typical spectrally encoded spread-time CDMA in the presence of multiple narrowband interference (NBI) signals in an additive white Gaussian noise channel. Furthermore, the authors demonstrate that by combining useful properties of ML-based receiver and three-level codes, that is, codes with values of -1, 0, +1, the authors can introduce a new strategy in which superior performance with respect to previous receiver structure based on two-level codes, that is, codes with values of -1, +1, can be attained. With the help of an example, the authors drive, first, the...
Adaptive output feedback tracking controller for a class of uncertain strict feedback nonlinear systems in the absence of state measurements
, Article International Journal of Systems Science ; Volume 43, Issue 2 , 2012 , Pages 201-210 ; 00207721 (ISSN) ; Shahrokhi, M ; Sharif University of Technology
2012
Abstract
In this article, design of an adaptive control scheme for a class of uncertain single-input single-output systems in strict feedback form via a backstepping technique has been proposed. It is assumed that system output and its derivatives are available. By virtue of the observability concept, it is shown that for this class of systems there exists a one-to-one map, which maps output and its derivatives to system states. By means of this mapping and using linearly parametrised approximators, such as fuzzy logic systems or neural networks, the uncertain nonlinear dynamics and unavailable states are estimated. The proposed adaptive controller guarantees that the closed-loop system is uniformly...
Storage-aware value prediction
, Article Proceedings - 13th Euromicro Conference on Digital System Design: Architectures, Methods and Tools, DSD 2010, 1 September 2010 through 3 September 2010, Lille ; 2010 , Pages 722-728 ; 9780769541716 (ISBN) ; Baniasadi, A ; Sharif University of Technology
2010
Abstract
Despite the huge potential, value predictors have not been used in modern processors. This is partially due to the complex structures associated with such predictors. In this paper we study value predictors and investigate solutions to reduce storage requirements while imposing negligible coverage cost. Our solutions build on the observation that conventional value predictors do not utilize storage efficiently as they allocate too much space for small and frequently appearing values. We measure data width requirement and entropy in a subset of predictor resources and show that values stored in predictors show limited sizes and very small entropy. We exploit this behavior and suggest...
A hardware platform for evaluating low-energy multiprocessor embedded systems based on COTS devices
, Article IEEE Transactions on Industrial Electronics ; Volume 62, Issue 2 , 2015 , Pages 1262-1269 ; 02780046 (ISSN) ; Ejlali, A ; Sharif University of Technology
2015
Abstract
Embedded systems are usually energy constrained. Moreover, in these systems, increased productivity and reduced time to market are essential for product success. To design complex embedded systems while reducing the development time and cost, there is a great tendency to use commercial off-the-shelf ("COTS") devices. At system level, dynamic voltage and frequency scaling (DVFS) is one of the most effective techniques for energy reduction. Nonetheless, many widely used COTS processors either do not have DVFS or apply DVFS only to processor cores. In this paper, an easy-to-implement COTS-based evaluation platform for low-energy embedded systems is presented. To achieve energy saving, DVFS is...
Development and validation of an EFL self-regulated learning questionnaire
, Article Southern African Linguistics and Applied Language Studies ; Volume 33, Issue 1 , Mar , 2015 , Pages 63-79 ; 16073614 (ISSN) ; Jafari, H ; Sharif University of Technology
Routledge
2015
Abstract
Self-regulated learning, strangely enough, though having swept educational psychology’s literature like a tidal wave and also, compared to other constructs such as metacognition and learning strategies, has remained rather uncharted in language education literature and L2 research. Hence, among the main purposes of the current study was to form a link, even tenuous, between the two fields by developing a questionnaire in English and Persian to measure self-regulated language learning capacity and behaviour of Iranian EFL learners. The development of the inventory was guided by two pilots (412 participants), content validation by expert judgment, cognitive interviews, expert review of the...
Adaptive fuzzy backstepping approach for temperature control of continuous stirred tank reactors
, Article Fuzzy Sets and Systems ; Volume 160, Issue 12 , 2009 , Pages 1804-1818 ; 01650114 (ISSN) ; Shahrokhi, M ; Sharif University of Technology
2009
Abstract
In this paper, an adaptive fuzzy controller, based on backstepping technique, has been proposed for temperature control of a general class of continuous stirred tank reactors (CSTRs). Using the observability concept, an adaptive fuzzy controller using temperature measurement has been designed. A fuzzy logic system is used to estimate the concentration dependent terms and other unknown system parameters appearing in the control law. It is shown that the closed loop system is asymptotically stable and influences of minimum approximation error and external disturbance on the L2 norm of the output tracking error can be attenuated arbitrarily. The performance of the proposed controller has been...
Receptive intelligibility of Turkish to Iranian-Azerbaijani speakers
, Article Cogent Education ; Volume 4, Issue 1 , 2017 ; 2331186X (ISSN) ; Neysani, A ; Sharif University of Technology
Taylor and Francis Ltd
2017
Abstract
Azerbaijani and Turkish are two closely-related languages from Oguz branch of Turkic languages, which are said to be mutually intelligible. Regarding this background, we designed an experiment within the framework of receptive multilingualism to investigate the role of linguistic factors in intelligibility of the Turkish language to Iranian Azerbaijanis. The study was carried out by controlling extra-linguistic factors such as language contact and negative attitude in order to make the findings attributable to only linguistic factors as the main focus of the present study. In the study, 40 native speakers of Azerbaijani in Iran were exposed to the Turkish language through short videos...