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electronics-engineering
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, M.Sc. Thesis Sharif University of Technology ; Mokhtari, Hosain (Supervisor)
Abstract
By taking a new sight into the system dynamic equations, the controllers are designed based on the simplification and converting higher order dynamics to the first order systems. This issue not only simplifies controller design but also stabilize system in all operational points. Moreover, proposed controllers are applied to the parallel Active Power Filters (APFs) because of the new trends in modularizing of APFs. On the other hand, the IEEE-1459 standard has proposed new definitions for the power in unbalanced and non-sinusoidal conditions and it stimulated researchers to use this standard for controlling APF directly. However, the proposed definitions are based on RMS values and...
Expansion of Power Definition in IEEE-1459 in Order to Apply to Shunt Active Power Filters
, M.Sc. Thesis Sharif University of Technology ; Mokhtari, Hossein (Supervisor)
Abstract
Increase of nonlinear loads has led rise of harmonic currents, voltage distortion and imbalance in power system. Those polluted nonsinusuidal environments have made electrical engineer and researchers to define new and more compelet definition of electrical power quantities such as power factor, apparent power, THD and … . The new definitions have resulted in new methods of power quality enhancement technique. IEEE-1459 Std. proposes definitions for electric power in sinusoidal, nonsinusoidal, balanced and unbalanced conditions which can be used for compensation of nonsinusoidal and unbalanced systems. This reaserch introduces a new method to obtain shunt active filter reference signal. This...
Enhancement of MAC Protocol of WiGig Network
, M.Sc. Thesis Sharif University of Technology ; Manzuri Shalmani, Mohammad Taghi (Supervisor) ; Ajorloo, Hossein (Co-Advisor)
Abstract
The 60 GHz high speed technology, is the interesting category in network world nowadays. In this study, we consider one of the 60 GHz technologies as it is called WiGig. WiGig works under IEEE802.11ad standard, one of the WLAN standards that works at 60 GHz frequency band. We have surveyed the total MAC and physical layer of this standard to find the way to enhance the MAC protocol. This MAC protocol is applying the CSMA/CA and TDMA methods to access the channel. We have applied the CSMA/CA in our thesis that is a contention based access method. We found that with this method our network is not fair. Since there are not any studies about the value of Fairness in this standard, we...
Throughput Analysis of Routing Algorithms in 802.11s-Based Wireless Mesh Networks
, M.Sc. Thesis Sharif University of Technology ; Ashtiani, Farid (Supervisor)
Abstract
Wireless Mesh Networks (WMNs) can be considered as the result of cooperation among two ad hoc networks, one composed of Mesh Points (MPs) and another one composed of Mesh Clients (MCs) as well as corresponding Access (Mesh) Points. Each one has its own functions and properties. This cooperation results in a flexible network that to fully demonstrate its potentials, requires special routing algorithms and access schemes.Here, we study and analyze three routing algorithms in IEEE 802.11s-based WMNs from throughput point of view. To this end, each node in the network is modeled by a queue during Contention-Free Periods (CFPs). During Contention-Based Period, however, to simplify modeling, we...
Application of Software-defined Networking in Enterprise WLAN
, M.Sc. Thesis Sharif University of Technology ; Hemmatyar, Ali Mohamad Afshin (Supervisor)
Abstract
Wireless LANs are becoming widespread in enterprises due to extensive usage of mobile devices and appearance of bring-your-own-device policies. However, mechanisms common in home WLANs are not sufficient for managing lots of access point and clients in an enterprise WLAN and WLAN controllers which are used in enterprises nowadays are limited to a fixed set of commands operated from a CLI and the source code is not changeable. Also, their effectiveness can be harvested alongside access points from the same vendor. Thus, dynamic high level programming for whole network configuration is an absolute need in this changing business environment and Software-defined Networking (SDN) will empower us...
Design and Implementation of a Ultra-Wideband Pulse Interference Immune Communications
, M.Sc. Thesis Sharif University of Technology ; Fotowat-Ahmady, Ali (Supervisor) ; Medi, Ali (Supervisor)
Abstract
One of the serious challenges in Ultra-Wideband (UWB) systems, especially Impulse radio (IR) systems, is the IEEE 802.11a in the middle of the UWB band (In band Interferer) which affects the system performance severely. Matched filter concept shapes the output noise based on its spectrum. For solving the mutual interference between UWB and narrow-band (NB) systems, the unique properties of modified Hermite pulses is utilized to develop a pulse for UWB communications. Matched filter is implemented by designing this pulse featuring notches that can be tuned to a certain frequency. Therefore, NB interferer can be nulled out passing through the matched filter. 0.18 µm CMOS technology has been...
Seismic Design of Substation Structures with Consideration of IEEE-693
, M.Sc. Thesis Sharif University of Technology ; Mofid, Massoud (Supervisor)
Abstract
The Reliability of substation structures with consideration of earthquake uncertainties is one of the most important subjects in structural analysis in recent years. In this project we first introduce IEEE-693-2005, which is the most effective and comprehensive seismic design code for electronic substations. Also in second chapter the rudimentary aspects of Reliability Theory and methods for evaluating the reliability of substation structures is introduced. Then with modeling the most common and most important electronic substation devices in Iran, with consideration of all seismic parameters and their uncertainties, the reliability of these structures evaluated. In this project for...
LiFi grid: A machine learning approach to user-centric design
, Article Applied Optics ; Volume 59, Issue 28 , 2020 , Pages 8895-8901 ; Nezamalhosseini, S. A ; Salehi, J. A ; Sharif University of Technology
OSA - The Optical Society
2020
Abstract
A novel machine learning (ML) clustering algorithm, named light-fidelity (LiFi) Grid, is proposed to design amorphous cells of LiFi access points (APs) in order to maximize the minimum signal-to-interference-plus-noise ratio (SINR) from the viewpoint of user-centric (UC) network design. The algorithm consists of two phases. Explicitly, the first phase consists of finding clusters of user densities based on the mean-shift (MS) clustering algorithm. In contrast to some other clustering algorithms, such as K-means, MS does not need to know the number of clusters in advance. Furthermore, the combined transmission scheme is assumed in each cell. In the second phase, this paper proposes a novel...
Day-ahead power system scheduling considering water consumption in power plants
, Article International Transactions on Electrical Energy Systems ; Volume 29, Issue 12 , 2019 ; 20507038 (ISSN) ; Ganjkhani, M ; Safdarian, A ; Li, L ; Sharif University of Technology
John Wiley and Sons Ltd
2019
Abstract
Power generation consumes a substantial amount of water in the power industry. In order to address the impact of water consumption restriction on the power generation, this paper proposes a security-constrained unit commitment (SCUC) formulation considering water consumption impact as an additional constraint. To this end, the water consumption in power plants is formulated. Consequently, the SCUC is extended to consider the consumed water volume as a restricting factor. A procedure is introduced to investigate the most appropriate point of power generation operation to save a vital amount of water by raising reasonable generation costs. The objective of the proposed model is to minimize the...
Low power DAC with single capacitor sampling method for SAR ADCs
, Article Electronics Letters ; Volume 52, Issue 14 , 2016 , Pages 1209-1210 ; 00135194 (ISSN) ; Khorami, A ; Sharifkhani, M ; Sharif University of Technology
Institution of Engineering and Technology
2016
Abstract
An ultra-efficient switching method for successive approximation register ADCs is proposed. In this method, the input signals are sampled in a special fashion to reduce the switching energy. Owing to the sampling method, only one reference voltage (Vq=Vref/4) is required to implement the switching steps. Therefore, in addition to reduction in the switching energy (due to the lower supply voltage), the precision of the DAC is improved. The proposed method reduces the switching energy and area by 99.41 and 50%, respectively, compared with the conventional method. © 2016 The Institution of Engineering and Technology
Passive realization of fractional-order impedances by a fractional element and rlc components: conditions and procedure
, Article IEEE Transactions on Circuits and Systems I: Regular Papers ; Volume 64, Issue 3 , 2017 , Pages 585-595 ; 15498328 (ISSN) ; Tavazoei, M. S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2017
Abstract
In this paper, conditions for checking the realizability of fractional-order impedance functions by passive networks composed of a fractional element (either a fractional capacitor or a fractional inductor) and some RLC components are derived. To this end, at first the newly obtained conditions for realizability of fractional-order impedance functions by a passive network composed of a fractional capacitor and some RLC components are extended to include the case that the polynomials involving in the impedance function can have roots on the imaginary axis. Then, the necessary and sufficient conditions are found on a fractional-order impedance function to be realized by a passive network...
A new framework to train autoencoders through non-smooth regularization
, Article IEEE Transactions on Signal Processing ; Volume 67, Issue 7 , 2019 , Pages 1860-1874 ; 1053587X (ISSN) ; Ghaemmaghami, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Deep structures consisting of many layers of nonlinearities have a high potential of expressing complex relations if properly initialized. Autoencoders play a complementary role in training a deep structure by initializing each layer in a greedy unsupervised manner. Due to the high capacity presented by autoencoders, these structures need to be regularized. While mathematical regularizers (based on weight decay, sparsity, etc.) and structural ones (by way of, e.g., denoising and dropout) have been well studied in the literature, quite a few papers have addressed the problem of training autoencoder with non-smooth regularization. In this paper, we address the problem of training autoencoder...
Timing Modulation for Macro-Scale Molecular Communication
, Article IEEE Wireless Communications Letters ; Volume 9, Issue 9 , 2020 , Pages 1356-1360 ; Zlatanov, N ; Gohari, A ; Nasiri Kenari, M ; Mirmohseni, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
In this letter, we propose a novel communication scheme for macro-scale molecular timing channels (MTCs), where the information carrier is the release time of the molecules. Next, the symbol constellation, receiver's sampling time, and receiver's decision rule are designed and analyzed. We further propose a computationally simple yet optimal receiver. Our numerical results show that macro-scale MTC is an approach for achieving ultra-reliable molecular communication. © 2012 IEEE
Simplification of integrated multi-turn wound-rotor resolvers' manufacturing
, Article IEEE Sensors Journal ; Volume 20, Issue 23 , 2020 , Pages 14141-14147 ; Tootoonchian, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Employing Multi-Turn Wound-Rotor (WR) resolvers are suggested for applications that high accuracy and absolute measurement are required, simultaneously. Conventional multi-turn resolvers are consisted of two individual resolvers in a common frame and suffer from high cost and big size that has a loading effect on the driven machine. Those challenges are over-come in proposed structures of recent researches in the price of a complicated winding process in manufacturing where the aim of this paper is laying. To find the best solution, an index is proposed and calculated. All the simulations are done using time-stepping finite element analysis (TSFEA). Then, the prototype of the optimal...
Influence of different installation configurations on the position error of a multiturn wound-rotor resolver
, Article IEEE Sensors Journal ; Volume 20, Issue 11 , 2020 , Pages 5785-5792 ; Alipour Sarabi, R ; Nasiri Gheidari, Z ; Tootoonchian, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Multi-turn resolvers are proposed to be used in high accuracy, high-reliability applications that need to have the benefits of absolute measurement and high accuracy, simultaneously. In this paper, the influence of different arrangements of rotary transformer (RT) and resolvers' core on the accuracy of a multi-turn wound rotor (WR) resolver is discussed. Then, an optimal configuration with the aim of reducing the total cost, and the total volume of the sensor is proposed. All the analysis is done using 3-D time-variant finite element method (3-D TVFEM) and the optimal structure is built for experimental tests. Finally, experimental measurements are employed to verify the simulation results....
Conditions on polynomials involved in admittance functions passively realizable by using rlc and two fractional elements
, Article IEEE Transactions on Circuits and Systems II: Express Briefs ; Volume 67, Issue 6 , 2020 , Pages 999-1003 ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
This brief deals with finding the necessary conditions which should be met by the polynomials appeared in the admittance functions passively realizable by using RLC components and two fractional elements. These conditions include structurally necessary equalities/specifications and positive-realness-based inequalities which should be satisfied by the involved polynomials. In the realizable cases, the acceptable region for choosing the pseudo inductances/capacitances of fractional elements is found from the obtained conditions. © 2004-2012 IEEE
Private Information Retrieval for a Multi-Message Scenario with Private Side Information
, Article IEEE Transactions on Communications ; Volume 69, Issue 5 , 2021 , Pages 3235-3244 ; 00906778 (ISSN) ; Shariatpanahi, S. P ; Maddah Ali, M. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
We consider the problem of private information retrieval (PIR), where a single user with private side information (PSI) aims to retrieve multiple files from a library stored at some servers. We assume that the side information (SI) at the user includes a subset of files stored privately. Moreover, the identity of requests and side information at the user are not revealed to any of the servers. The problem involves finding the minimum load transmitted from the servers to the user such that the requested files can be decoded with the help of received data and side information. By providing matching lower and upper bounds for certain regimes, we characterize the minimum load imposed on all the...
Decomposition of the time delay systems with one delay: The simultaneous similarity of two matrices
, Article ELECO 2013 - 8th International Conference on Electrical and Electronics Engineering, Bursa ; 2013 , Pages 487-491 ; 9786050105049 (ISBN) ; Haeri, M ; Sharif University of Technology
IEEE Computer Society
2013
Abstract
The time delay equations are frequently used to model real systems since they can describe the after-effect phenomenon. It is usually difficult to analyze the properties of time delay systems. Thus it would be beneficial to make the systems as simple as possible. For this purpose, the decomposition of the systems into some separate or cascaded sub-systems with smaller dimension is introduced as the solution of the mentioned complex task. The decomposition of the time delay systems with one delay is directly related to simultaneous similarity of two matrices. In this regard, necessary and sufficient conditions are derived for the existence of a common similar block diagonal or triangular form...
Adaptive leader-following consensus in multi-agent systems with second-order nonlinear dynamics and directed switching topologies
, Article 8th International Conference on Electrical and Electronics Engineering, ELECO 2013, Bursa, 28 November 2013 through 30 November 2013 ; 2013 , Pages 482-486 ; 9786050105049 (ISBN) ; Haeri, M ; Sharif University of Technology
IEEE Computer Society
2013
Abstract
In this paper, we develop control algorithms for addressing second-order consensus problems in intrinsically second-order nonlinear multi-agent dynamical systems with switching topologies. The proposed adaptive controller applies a leader-following strategy in which all agents are assumed to be informed of the leader's state. Another feature of this work which specifically distinguishes it from others is that the proposed controller uses undirected and directed graphs to accommodate for a full range of possible graph information topologies without limitations of bidirectional communication
RETRACTED ARTICLE: Design, optimization and experimental evaluation of a novel tactile sensor for large surgical grasper
, Article ICMEE 2010 - 2010 2nd International Conference on Mechanical and Electronics Engineering, Proceedings ; Volume 2 , 2010 , Pages V2111-V2116 ; 9781424474806 (ISBN) ; Shamsollahi, M. J ; Mirbagheri, A ; Farahmand, F ; Sharif University of Technology
IEEE Computer Society
2010
Abstract
There has been a rising trend towards robotic tele-surgery operations in recent years. A major concern, however, is the lack of direct contact between the surgeon and patient's body. Several researchers have proposed various designs of tactile sensors for surgical instruments to improve the dexterity of surgeons. Previously designed sensors, however, are mostly suitable for instruments with small contact areas. In this paper, a novel tactile sensor is introduced in integration with the teeth of a surgical grasper for large organs. It includes strain gauges embedded underneath a toothed plate, which also act as grasping teeth of the jaws of the instrument. The thickness of the plate and the...