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A method for automatic tuning the memristance of memristive devices with the capacity of applying to memristive memories
, Article 2012 International Conference on Computer Systems and Industrial Informatics, ICCSII 2012, 18 December 2012 through 20 December 2012 ; December , 2012 ; 9781467351577 (ISBN) ; Merrikh Bayat, F ; Mirebrahimi, N ; Sharif University of Technology
2012
Abstract
Memristor is the fourth fundamental passive circuit element which has potential applications in development of analog memristive memories, neuroscience, and brain simulation. In all of these applications the memristance of the device should be adjusted to the desired value, which is currently performed by trial and error. The aim of this paper is to propose a new method and develop a circuit for automatic adjustment of the memristance of memristive devices. The proposed method is based on the sliding mode control and numerical simulations show that it can be used for tuning the memristance of such devices with a high accuracy
The neuro-fuzzy computing system with the capacity of implementation on a memristor crossbar and optimization-free hardware training
, Article IEEE Transactions on Fuzzy Systems ; Vol. 22, Issue. 5 , 2014 , Pages 1272-1287 ; ISSN: 10636706 ; Merrikh-Bayat, F ; Shouraki, S. B ; Sharif University of Technology
2014
Abstract
In this paper, first we present a new explanation for the relationship between logical circuits and artificial neural networks, logical circuits and fuzzy logic, and artificial neural networks and fuzzy inference systems. This shows us that neural networks are working in the same way as logical circuits when the connection between them is through the fuzzy logic. However, themain difference between them is that logical circuits can be constructed without using any kind of optimization-based learning methods. Based on these results, we propose a new neuro-fuzzy computing system. As verified by simulation results, it can effectively be implemented on the memristor crossbar structure and...
Memristive fuzzy edge detector
, Article Journal of Real-Time Image Processing ; Vol. 9, issue. 3 , September , 2014 , pp. 479-489 ; Online ISSN: 1861-8219 ; Bagheri Shouraki, S ; Merrikh-Bayat, F ; Sharif University of Technology
2014
Abstract
Fuzzy inference systems always suffer from the lack of efficient structures or platforms for their hardware implementation. In this paper, we tried to overcome this difficulty by proposing a new method for the implementation of the fuzzy rule-based inference systems. To achieve this goal, we have designed a multi-layer neuro-fuzzy computing system based on the memristor crossbar structure by introducing a new concept called the fuzzy minterm. Although many applications can be realized through the use of our proposed system, in this study we only show how the fuzzy XOR function can be constructed and how it can be used to extract edges from grayscale images. One main advantage of our...
Memristor crossbar-based hardware implementation of fuzzy membership functions
, Article Proceedings - 2011 8th International Conference on Fuzzy Systems and Knowledge Discovery, FSKD 2011, 26 July 2011 through 28 July 2011 ; Volume 1 , July , 2011 , Pages 645-649 ; 9781612841816 (ISBN) ; Shouraki, S. B ; Merrikh Bayat, F ; Sharif University of Technology
2011
Abstract
In May 1, 2008, researchers at Hewlett Packard (HP) announced the first physical realization of a fundamental circuit element called memristor that attracted so much interest worldwide. This newly found element can easily be combined with crossbar interconnect technology which this new structure has opened a new field in designing configurable or programmable electronic systems. These systems in return can have applications in signal processing and artificial intelligence. In this paper, based on the simple memristor crossbar structure, we propose new and simple circuits for hardware implementation of fuzzy membership functions. In our proposed circuits, these fuzzy membership functions can...
Mesoporous silica nanoparticles (MCM-41) coated PEGylated chitosan as a pH-Responsive nanocarrier for triggered release of erythromycin [electronic resource]
, Article International Journal of Polymeric Materials and Polymeric Biomaterials ; 2014, Volume 63, Issue 13, Pages 692-697 ; Mazaheri Tehrani, Zahra ; Sharif University of Technology
Abstract
A pH-responsive drug delivery system based on core shell structure of mesoporous silica nanoparticle (MSN) and chitosan-PEG copolymer was prepared and characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and high-resolution transmission microscope (HR-TEM) techniques. In order to improve compatibility MSN and drug, mesoporous nanosilica was modified by 3-aminopropyl triethoxysilane. The release of erythromycin (a macrolide antibiotic) as a model drug was investigated in two pHs, 7.4 and 5.5
Theoretical and Computational Investigation of Quantum Plasmonic Properties of Nanocluster Dimers
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Zahra (Supervisor)
Abstract
In today's era, metal nanoparticles play an important role in technologies emerging from different sciences, such as chemistry, physics, optics, material science, due to their unique characteristics. In the development of nanooptics science, it can be said that metal nanoparticles play an important role. The ability of conductive electrons collective oscillation causes surface charge density fluctuations in nanoparticles, this phenomenon is known as surface plasmons. Surface plasmons are surprisingly coupled with light and cause the significant increase in the intensity of optical fields induced in nanoparticles. Therefore, with the presence of localized surface plasmons or plasmon...
Theoretical Investigation of Ab-initio MD Approach to Increase the Efficiency and Accuracy of VCD Spectrum Calculation
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Zahra (Supervisor)
Abstract
Understanding of the Molecules is the main purpose of the chemistry. Ab-initio molecular dynamics (AIMD) as a branch of the computational chemistry, tries to give us a deep comprehension of the molecule, and its chemical, physical and optical activities. This comprehension, relies on the accuracy of quantum mechanics, in addition to the speed of the classical mechanics. The mixing of the quantum mechanics and the classical mechanics could simulate activities of the atoms in the time-domain, provided the mixing is done with precaution. This, in turn, helps us to forecast the response of a molecule in different situations, and also translating the macroscopic phenomena in a nanoscopic...
Investigation of Plasmonic Excitation in Carbonic Nanostructures Within Near-IR
, M.Sc. Thesis Sharif University of Technology ; Jamshidi, Zahra (Supervisor)
Abstract
To date, the plasmonic properties of many metallic and semi-conducting materials have been investigated and used in various industries. One of the plasmonic material categories that have always been considered is polycyclic aromatic hydrocarbon or PAH, whose plasmonic resonance energy depends on the charge state of the molecule. In this regard, it is easy to change the plasmonic resonance energy via changing the induced charge, which is a unique feature of the mentioned materials. In addition, plasmonic structures with excitations in the infrared region are able to enhance the vibration intensity of absorbed molecules by increasing the electric field around themselves. Therefore, they have...
Using Nonlinear Effects of Light for Optical Signal Processing
, M.Sc. Thesis Sharif University of Technology ; Kavehvash, Zahra (Supervisor)
Abstract
Ultrafast signal processing in time-domain with high resolution and reconfigura-bility is a challenging task. This paper, for the first time, introduces a time-varying metasurface consisting of graphene microribbon array for implementing time-lens in the terahertz domain. Given that the surface conductivity of graphene is proportional to the Fermi energy level in the THz regime, it is possible to change the phase property of the incident electromagnetic pulse by changing the Fermi level while the Fermi level itself is a function of voltage. Upon this fact, a quadratic temporal phase modulator, namely time-lens has been realized. This phase modulation is applied to the impinging signal in the...
Using Simulation-Optimization Approach for Fire Station Location and Vehicle Assignment Problem: a Case Study in Tehran, Iran
, M.Sc. Thesis Sharif University of Technology ; Amini, Zahra (Supervisor)
Abstract
In this research, the problem of locating fire stations and allocating equipment has been studied and a simulation-optimization approach has been presented to solve the problem. The mathematical models of this research were developed based on the idea of the randomness of the covered demand and the maximum expected coverage model. In these models, the issue of non-availability of equipment to cover accidents, the random nature of accidents, various fire incidents and the equipment needed to cover them are considered. Two mathematical models with deterministic and non-deterministic approach with different scenarios for demand are proposed. The non-deterministic model is developed with the aim...
Introducing An Integrated Framework For Solving The Fleet Planning Problem Using A Simulation-Optimization Approach
, M.Sc. Thesis Sharif University of Technology ; Amini, Zahra (Supervisor)
Abstract
One of the main concerns of industrial companies’ managers is providing an efficient logistics system. To achieve an efficient logistics system, the fleet planning problem is studied by many researchers in recent years. This problem consists of multiple sub-problems at three levels: operational, tactical, and strategic. These sub-problems are closely related to each other and need to be studied and addressed in an integrated manner. In this research, an attempt is made to provide an integrated framework to solve the vehicle routing problem (operational), outsourcing problem (tactical), and fleet composition problem (strategic). These problems have various uncertainties, including customer...
Investigation of the scavenging mechanism of tyrosyl radical by hydroxybenzohydroxamic acid derivatives: A DFT study
, Article Computational and Theoretical Chemistry ; Volume 1018 , 2013 , Pages 35-44 ; 2210271X (ISSN) ; Fattahi, A ; Sharif University of Technology
2013
Abstract
The free radical scavenging activity of a series of hydroxybenzohydroxamic acid derivatives have been studied in gas phase, water and benzene environments, using the density functional theory. Different mechanisms of reactions have been considered: single electron transfer (SET), hydrogen atom transfer (HAT). Rate constants were determined to know if the radical scavenging activity of these compounds proceeds via an H-atom or an electron-transfer mechanism. Calculations showed that the presence of the adjacent hydroxyl groups on phenyl ring increases the radical stability through intramolecular hydrogen bonds. The calculated bond dissociation enthalpy (BDE) values for hydroxyl groups on...
A quantum chemical study on the OH radical quenching by natural antioxidant fisetin
, Article Journal of Physical Organic Chemistry ; Volume 30, Issue 11 , 2017 ; 08943230 (ISSN) ; Fattahi, A ; Sharif University of Technology
2017
Abstract
In this work, the antioxidant ability of fisetin was explored toward hydroxyl (•OH) radical in aqueous and lipid solution using density functional level of theory. Different reaction mechanisms have been studied: hydrogen atom transfer, single electron transfer followed by proton transfer, and radical adduct formation, and sequential proton loss electron transfer. Rate constants for all possible reaction sites have been calculated using conventional transition state theory in conjunction with the Collins-Kimball theory. Branching ratios for the different channels of reaction are reported for the first time. Results show that the reactivity of fisetin toward hydroxyl (•OH) radical takes place...
Influence of remote intramolecular hydrogen bonding on the acidity of hydroxy-1,4-benzoquinonederivatives: A DFT study
, Article Journal of Physical Organic Chemistry ; Volume 32, Issue 4 , 2019 ; 08943230 (ISSN) ; Fattahi, A ; Sharif University of Technology
John Wiley and Sons Ltd
2019
Abstract
In this study, the effects of the remote intramolecular hydrogen bonding on the acidity of hydroxy-1,4-benzoquinone derivatives have been investigated ab initio by employing density functional theory (DFT) methods. The computational studies were performed for both gas and solution (H 2 O, DMSO, and MeCN solutions) phases. Our results indicated that remote hydrogen bonding could play an important role in increasing the acidity of hydroxy-1,4-benzoquinone. Noncovalent interaction reduced density gradient (NCI-RDG) methods were used to visualize the attractive and repulsive interactions in the studied acids and their conjugate bases. Natural bond orbital (NBO) analysis was performed to confirm...
An optimal hybrid nuclear norm regularization for matrix sensing with subspace prior information
, Article IEEE Access ; Volume 8 , 2020 , Pages 130937-130946 ; Daei, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Matrix sensing refers to recovering a low-rank matrix from a few linear combinations of its entries. This problem naturally arises in many applications including recommendation systems, collaborative filtering, seismic data interpolation and wireless sensor networks. Recently, in these applications, it has been noted that exploiting additional subspace information might yield significant improvements in practical scenarios. This information is reflected by two subspaces forming angles with column and row spaces of the ground-truth matrix. Despite the importance of exploiting this information, there is limited theoretical guarantee for this feature. In this work, we aim to address this issue...
The free radical scavenging activity of lespedezacoumestan toward ˙OH radical: a quantum chemical and computational kinetics study
, Article Journal of Physical Organic Chemistry ; Volume 31, Issue 2 , February , 2018 ; 08943230 (ISSN) ; Fattahi, A ; Sharif University of Technology
John Wiley and Sons Ltd
2018
Abstract
The free radical activity of lespedezacoumestan was investigated toward hydroxyl (˙OH) radical in polar and nonpolar media using density functional theory. Four reaction mechanisms including radical adduct formation, hydrogen atom transfer, sequential single electron-proton transfer (SET-PT), and sequential proton loss electron transfer were considered. The rate constants and branching ratio for all possible sites of reaction were calculated and reported for the first time. According to the obtained results, lespedezacoumestan reacts faster with ˙OH radical in aqueous solution than in nonpolar media. Also, lespedezacoumestan is an excellent ˙OH radical scavenger regardless of the environment...
Transfer of d -level quantum states through spin chains by random swapping
, Article Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 75, Issue 2 , 2007 ; 10502947 (ISSN) ; Karimipour, V ; Sharif University of Technology
2007
Abstract
We generalize an already proposed protocol for quantum state transfer to spin chains of arbitrary spin. An arbitrary unknown d -level state is transferred through a chain with rather good fidelity by the natural dynamics of the chain. We compare the performance of this protocol for various values of d. A by-product of our study is a much simpler method for picking up the state at the destination as compared with the one proposed previously. We also discuss entanglement distribution through such chains and show that the quality of entanglement transition increases with the number of levels d. © 2007 The American Physical Society
Separating radar signals from impulsive noise using atomic norm minimization
, Article IEEE Transactions on Circuits and Systems II: Express Briefs ; Volume 68, Issue 6 , 2021 , Pages 2212-2216 ; 15497747 (ISSN) ; Daei, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
We consider the problem of corrupted radar super-resolution, a generalization of compressed radar super-resolution in which one aims to recover the continuous-valued delay-Doppler pairs of moving objects from a collection of corrupted and noisy measurements. The received signal in this type consists of contributions from objects, outlier and noise. While this problem is ill-posed in general, tractable recovery is possible when both the number of objects and corrupted measurements are limited. In this brief, we propose an atomic norm optimization in order to find the delay-Doppler pairs and the outlier signal. The objective function of our optimization problem encourages both sparsity in the...
Thermal effects on quantum communication through spin chains
, Article Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 71, Issue 4 , 2005 ; 10502947 (ISSN) ; Karimipour, V ; Sharif University of Technology
2005
Abstract
We study the effect of thermal fluctuations in a recently proposed protocol for transmission of unknown quantum states through quantum spin chains. We develop a low-temperature expansion for general spin chains. We then apply this formalism to study exactly thermal effects on short spin chains of four spins. We show that optimal times for extraction of output states are almost independent of the temperature, which lowers only the fidelity of the channel. Moreover we show that thermal effects are smaller in the antiferromagnetic chains than the ferromagnetic ones. © 2005 The American Physical Society
Advances in UAV-assisted localization: joint source and UAV parameter estimation
, Article IEEE Transactions on Vehicular Technology ; Volume 72, Issue 11 , 2023 , Pages 14268-14278 ; 00189545 (ISSN) ; Amiri, R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2023
Abstract
This paper presents efficient estimators to address the problem of source localization aided by unmanned aerial vehicles (UAVs) with unknown location parameters. Leveraging semidefinite relaxation technique and successive weighted least squares estimation, the source and UAV parameters are simultaneously estimated in both mixed line-of-sight/non-line-of-sight (NLOS) and NLOS scenarios. The proposed estimators are shown to approximately achieve the Cramer-Rao bound (CRB) under mild Gaussian noise conditions when the measurement noises are small compared to the associated ranges. Numerical simulations demonstrate that localization without prior UAV location information is still possible with a...