Analysis of Circular Slot Antenna on a Ferrite Substrate

, M.Sc. Thesis Sharif University of Technology Heydari, Mohammad Bagher (Author) ; Rajaei, Behzad (Supervisor)

Abstract

Circular polarization (CP) is one of the common polarization types used in wireless systems for frequency identification (RFID), global positioning (GPS) and wireless local area networks (WLAN), since it can provide greater flexibility in orientation angle between transmitter and receiver, and better mobility and weather penetration than the linearly polarized antennas. Magnetic permeability in ferrites can be tuned by external magnetic field ; So ferrites can be good candidates for new reconfigurable CP antenna technology. In this project, we will consider circularly polarized slot antenna with a wide axial ratio beamwidth that consists of a normally magnetized ferrite substrate mounted...

Anomalous Reflection and Transmission in Resonant Magneto-Optic Structures

, M.Sc. Thesis Sharif University of Technology Pahlavan, Payman (Author) ; Mehrany, Khashayar (Supervisor) ; Rajaei, Behzad (Co-Advisor)

Abstract

In this thesis, light transmission in dielectric slit arrays on metallic and magneto-optical material has been analyzed by mode matching method together with numerical simulations on commercial softwares such as Comsol Multiphysics and CST microwave studio. It has been shown that light transmission can be attributed to either the Fabry-Perot resonances or a collective resonance phenomenon across the array. In the first case, the transmission resonance is related to the slit depth and is confined to a single slit. In the second case; however, the resonant mechanism affects several neighboring slits. Surprisingly the former is converted to the latter by increasing the slit depth. Furthermore...

The Impact of Non-reciprocal One-way Propagation on the Coupling between Electromagnetic Resonators and Waveguides

, M.Sc. Thesis Sharif University of Technology Zarif, Arezoo (Author) ; Mehrany, Khashayar (Supervisor) ; Rajaei, Behzad (Co-Advisor)

Abstract

Subwavelength localization of electromagnetic energy with intense local fields, also known as electromagnetic hotspots, has received significant attention over the past few decades. In most cases the hotspot is achieved through the resonant concentration of electromagnetic fields. One way recently considered to get hotspot is through reflection of electromagnetic waves in nonreciprocal one-way structures, in plasmonics and via magneto optic effect.However these hotspots are less confined compared to hotspots caused by resonances. So combining nonreciprocal structures with resonance can provide better hotspots.Our aim in this thesis is to study nonreciprocal resonant structures using coupled...

Green's Function of a 2D Array of Holes Near the Frequency of Extraordinary Transmission

, M.Sc. Thesis Sharif University of Technology Mohammadi, Milad (Author) ; Memarian, Mohammad (Supervisor) ; Rajaei, Behzad (Supervisor)

Abstract

This thesis formulates Green's function of periodic arrays of two-dimensional rectangular holes Perforated on a PEC film. Green's function of two-dimensional periodic free space in the spectrum domain is computed. Using Floquet theory and considering the holes as rectangular waveguides, Green's function of the structure is presented.For sub-wavelength holes in cut-off and propagating cases, numerical results are presented. The effects of changing the aperture's thickness and the number of required modes have been reported. The structure under a normal and oblique incident wave is investigated, and the high conformity of the presented model results and full-wave simulations is observed.In...

Analysis of Graphene Plasmonic Waveguide with Inhomogeneous Substrate in Terahertz Band

, M.Sc. Thesis Sharif University of Technology Rezaei, Zohreh (Author) ; Borji, Amir (Supervisor) ; Rajaei, Behzad (Supervisor)

Abstract

Due to its extensive applications in imaging, data security, medication, etc., Terahertz has attaracted an ever-inceasing attention. Design and implementation of Terahertz sources and circuits as waveguide, filters, etc. in this band have attracted attention. The unique elec-tric characteristics of graphene, like showing plasmonic characteristics in Terahertz frequency band, made this recently recognized matter a promising one to build super-integrated plas-monic circuits in Terahertz band. In this text, the first section represents an introduction for a number of graphene waveguides as well as studying the effective refractive index method to analyze graphene waveguides. Due to the small...

Single event upset immune latch circuit design using C-element

, Article Proceedings of International Conference on ASIC, 25 October 2011 through 28 October 2011, Xiamen ; 2011 , Pages 252-255 ; 21627541 (ISSN) ; 9781612841908 (ISBN) Rajaei, R ; Tabandeh, M ; Sharif University of Technology

2011

Abstract

Downscaling trend in CMOS technology on the one hand and reducing supply voltage of the circuits on the other hand, make devices more susceptive to soft errors such as SEU. Latch circuits are prone to be affected by SEUs. In this article, we propose a new circuit design of latch using redundancy with the aim of immunity against SEUs. According to simulation results, our design not only guaranties full immunity, but also has the advantage of occupying less area and consuming much less power and performance penalty in comparison with other SEU immune latches. The simulation results show that our solution has 65.76% reduction in power and about 50.65% reduction in propagation delay in...

Azote Removal in Submerged Fixed Bed Reactor by Modified Ludzack-Ettinger (MLE)Process

, M.Sc. Thesis Sharif University of Technology Rajaei, Forough (Author) ; Borgheei, Mahdi (Supervisor)

Abstract

Nitrogen compounds are becoming increasingly important in wastewater management, because of the many effects that nitrogenous material can have on the environment that need nitrogen removal. In this study, the performance of a submerged fixed bed reactor in nitrogen removal, constructed two anoxic and aerobic sections under Modified Ludzack-Ettinger process was investigated. Laboratory experiments were conducted at a constant COD concentration of 350 mg/lit, hydraulic retention times of 8, 12 and 18 hours and influent ammonia loading rate between 0.128 and 0.955 g NH3/m2.day. Nitrogen removal efficiency was obtained between 80.4 and 97.3%, and COD removal efficiency was achieved between 88.9...

Soft error rate estimation for combinational logic in presence of single event multiple transients

, Article Journal of Circuits, Systems and Computers ; Vol. 23, issue. 6 , 2014 Rajaei, R ; Tabandeh, M ; Fazeli, M ; Sharif University of Technology

2014

Abstract

Fast and accurate estimation of soft error rate in VLSI circuits is an essential step in a soft error tolerant ASIC design. In order to have a cost effective protection against radiation effects in combinational logics, an accurate and fast method for identification of most susceptive gates and paths is needed. In this paper, an efficient, fast and accurate method for soft error propagation probability (SEPP) estimation is presented and its performance is evaluated. This method takes into account all three masking factors in multi cycles. It also considers multiple event transients as a new challenge in soft error tolerant VLSI circuit design. Compared with Monte Carlo (MC) simulation-based...

Low cost soft error hardened latch designs for nano-scale CMOS technology in presence of process variation

, Article Microelectronics Reliability ; Volume 53, Issue 6 , June , 2013 , Pages 912-924 ; 00262714 (ISSN) Rajaei, R ; Tabandeh, M ; Fazeli, M ; Sharif University of Technology

2013

Abstract

In this paper, two Low cost and Soft Error Hardened latches (referred to as LSEH1 and LSEH2) are proposed and evaluated. The proposed latches are fully SEU immune, i.e. they are capable of tolerating all particle strikes to any of their nodes. Moreover, they can mask Single Event Transients (SETs) occurring in combinational logics and reaching the input of the latches. We have compared our SEU/SET-tolerant latches with some well-known previously proposed soft error tolerant latches. To evaluate the proposed latches, we have done a set of SPICE simulations. The simulation results trough comparisons with other hardened latches reveal that the proposed latches not only have more robustness but...

Single Event Multiple Upset (SEMU) tolerant latch designs in presence of process and temperature variations

, Article Journal of Circuits, Systems and Computers ; Volume 24, Issue 1 , January , 2015 ; 02181266 (ISSN) Rajaei, R ; Tabandeh, M ; Fazeli, M ; Sharif University of Technology

World Scientific Publishing Co. Pte Ltd 2015

Abstract

In this paper, we propose two novel soft error tolerant latch circuits namely HRPU and HRUT. The proposed latches are both capable of fully tolerating single event upsets (SEUs). Also, they have the ability of enduring single event multiple upsets (SEMUs). Our simulation results show that, both of our HRPU and HRUT latches have higher robustness against SEMUs as compared with other recently proposed radiation hardened latches. We have also explored the effects of process and temperature variations on different design parameters such as delay and power consumption of our proposed latches and other leading SEU tolerant latches. Our simulation results also show that, compared with the reference...

Quantum discrepancy: A non-commutative version of combinatorial discrepancy

, Article Electronic Journal of Combinatorics ; Volume 27, Issue 2 , 2020 , Pages 1-29 Alishahi, K ; Rajaee, M ; Rajaei, A ; Sharif University of Technology

Australian National University 2020

Abstract

In this paper, we introduce a notion of quantum discrepancy, a non-commutative version of combinatorial discrepancy which is defined for projection systems, i.e. finite sets of orthogonal projections, as non-commutative counterparts of set systems. We show that besides its natural algebraic formulation, quantum discrepancy, when restricted to set systems, has a probabilistic interpretation in terms of determinantal processes. Determinantal processes are a family of point processes with a rich algebraic structure. A common feature of this family is the local repulsive behavior of points. Alishahi and Zamani (2015) exploit this repelling property to construct low-discrepancy point...

Sliding-mode control of z-source inverter

, Article 34th Annual Conference of the IEEE Industrial Electronics Society, IECON 2008, Orlando, FL, 10 November 2008 through 13 November 2008 ; 2008 , Pages 947-952 ; 9781424417667 (ISBN) Rajaei, A.H ; Kaboli, S ; Emadi, A ; Sharif University of Technology

IEEE Computer Society 2008

Abstract

In this paper, sliding-mode control (SMC) is applied to a z-source converter to control output dc voltage of impedance network. The converter is assumed working in continuous conduction mode (CCM). First a comprehensive review of the literature for z-source inverter (ZSI) and use of sliding mode control in switched converters are performed. The procedure of SMC design used in ZSI is presented. The simulations for the application of SMC in z-source inverter are made and the results are illustrated. The results verify the effectiveness and robustness of the controller. © 2008 IEEE

A new approach of optimal appliance scheduling for peak load reduction of an off-grid residential building

, Article Journal of Building Performance Simulation ; Volume 16, Issue 2 , 2023 , Pages 131-143 ; 19401493 (ISSN) Rajaei, A ; Haddadi, M ; Nord, N ; Sharif University of Technology

Taylor and Francis Ltd 2023

Abstract

Demand for electricity, due to the fast growth in urbanization and industrialization, is on the rapid rise. Load shift is a basic method for demand side management (DSM) that can be used by the central controller in buildings and can lead to the maximum use of renewable energy sources, maximum economic benefits, and reduction of peak demand. This paper proposes an algorithm for shifting the flexible loads of four selected appliances with respect to boundary limits for each appliance. A standalone four-story building with different number of occupants is considered to evaluate this algorithm. The algorithm was trained on Richardson model to minimize two objectives including aggregated demand,...

Separating and Bi-separating Maps and Their Relation to Banach-Stone Theorem

, M.Sc. Thesis Sharif University of Technology Rajaei, Reza (Author) ; Ranjbar Motlagh, Alireza (Supervisor)

Abstract

Let C(S) and C(T) denote the sup-normed Banach spaces of real or complex-valued continuous functions on the compact Hausdorff spaces S and T, respectively. A linear map H:C(T)→C(S) is called separating if, for x,y∈C(T), xy≡0 implies HxHy≡0. In the second chapter of this thesis, we will show that any continuous separating map is a continuous multiple of a composition map. Moreover, it will be proved that any linear separating isomorphism of C(T) onto C(S) is continuous. We will also define separating and biseparating maps on the rings of continuous functions equipped with the compact-open topology. In addition, vector-valued separating maps will be investigated. For example, assume that C(T)...

Solving Congestion Pricing and Network Design Problem Simultaneously for Conventional and Automated Vehicles

, M.Sc. Thesis Sharif University of Technology Rajaei, Alireza (Author) ; Zokaei Aashtiani, Hedayat (Supervisor)

Abstract

In this dissertation, transportation networks with two classes of vehicles, including conventional vehicles and autonomous vehicles, have been studied. Four problems, including traffic assignment problem with two classes, congestion pricing problem for conventional vehicles, network design problem for autonomous vehicles, and simultaneous congestion pricing and network design problem, have been modeled and algorithms to solve them are presented. In this study, a dynamic penalty function algorithm is used to solve the congestion pricing problem, and a heuristic algorithm is used to solve the network design problem. Besides, the two-class traffic assignment problem is solved using the...

Simulation and Optimization of Downhole Pumps with Focus on IOR Application in Iranian Fields

, M.Sc. Thesis Sharif University of Technology Rajaei, Mohammad Mahdi (Author) ; Shad, Saeed (Supervisor)

Abstract

Three-dimensional (3D) computational fluid dynamics (CFD) was used in this study to investigate single and multi phase flow behavior related to three stages of ESP pump. Compared to experimental measurements, the numerical prediction for single phase flow of water is matched very well. Furthermore, the effects of viscosity and pump rotational speed for oil were investigated and the results show that by increasing oil viscosity and decreasing rotational speed, the pump head and efficiency reduced. ESP performance under two phase oil-methane flow and the effect of oil viscosity, rotational speed, intake pressure, gas bubble diameter, oil rate and gas volume fraction were studied. ESP boosting...

Developing a New Mechanism for Managing Technical Issues of Energy Transactions in Transactive Energy Market

, M.Sc. Thesis Sharif University of Technology Rajaei, Ali (Author) ; Fotuhi Firuzabad, Mahmud (Supervisor)

Abstract

Distribution power systems are undergoing a fundamental transition with the introduction of microgrids (MGs) and proliferation of renewable energy sources inspired mainly by privacy and environmental concerns. In this regard, energy management methods employed by utilities should take into account the intermittent nature of RESs power production while coping with the independent operation of MGs. Transactive energy (TE) is an emerging concept which utilizes economic-based mechanisms to facilitate the dynamic and decentralized management of active agents of the system. However, the energy transactions between transactive agents could have adverse impacts on the technical aspect of the system...

An energy-aware methodology for mapping and scheduling of concurrent applications in MPSoC architectures

, Article 2011 19th Iranian Conference on Electrical Engineering, ICEE 2011, 17 May 2011 through 19 May 2011 ; May , 2011 , Page(s): 1 ; ISSN : 21647054 ; 9789644634284 (ISBN) Rajaei, R ; Hessabi, S ; Vahdat, B. V ; Sharif University of Technology

2011

Abstract

Mapping and Scheduling are two central and critical steps in design flow of the Networks on Chips (NoCs). They deal with implementation of the applications on NoCs. In this paper a novel energy aware algorithm, called EAMS, for mapping and scheduling of concurrent applications to NoC platforms is developed. It is considered that, the NoC architecture consists of a set of heterogeneous IP cores. The introduced algorithm finds a mapping of the tasks of the application to available IP cores so that the overall energy consumption, meeting task deadlines, is minimized

Design of robust SRAM cells against single-event multiple effects for nanometer technologies

, Article IEEE Transactions on Device and Materials Reliability ; Volume 15, Issue 3 , 2015 , Pages 429-436 ; 15304388 (ISSN) Rajaei, R ; Asgari, B ; Tabandeh, M ; Fazeli, M ; Sharif University of Technology

2015

Abstract

As technology size scales down toward lower two-digit nanometer dimensions, sensitivity of CMOS circuits to radiation effects increases. Static random access memory cells (SRAMs) that are mostly employed as high-performance and high-density memory cells are prone to radiation-induced single-event upsets. Therefore, designing reliable SRAM cells has always been a serious challenge. In this paper, we propose two novel SRAM cells, namely, RHD11 and RHD13, that provide more attractive features than their latest proposed counterparts. Simulation results show that our proposed SRAM cells as compared with some state-of-the-art designs have considerably higher robustness against single-event...

Single event multiple upset-tolerant SRAM cell designs for nano-scale CMOS technology

, Article Turkish Journal of Electrical Engineering and Computer Sciences ; Volume 25, Issue 2 , 2017 , Pages 1035-1047 ; 13000632 (ISSN) Rajaei, R ; Asgari, B ; Tabandeh, M ; Fazeli, M ; Sharif University of Technology

Turkiye Klinikleri Journal of Medical Sciences 2017

Abstract

In this article, two soft error tolerant SRAM cells, the so-called RATF1 and RATF2, are proposed and evaluated. The proposed radiation hardened SRAM cells are capable of fully tolerating single event upsets (SEUs). Moreover, they show a high degree of robustness against single event multiple upsets (SEMUs). Over the previous SRAM cells, RATF1 and RATF2 offer lower area and power overhead. The Hspice simulation results through comparison with some prominent and state-of-the-art soft error tolerant SRAM cells show that our proposed robust SRAM cells have smaller area overhead (RAFT1 offers 58% smaller area than DICE), lower power delay product (RATF1 offers 231.33% and RATF2 offers 74.75%...