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rezazadeh-sotudeh--ghasem
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Design and Implementation of High Efficient Power Converter for Small PM Synchronous Wind Generator
, M.Sc. Thesis Sharif University of Technology ; Tahami, Farzad (Supervisor)
Abstract
The global wind energy capacity has been increased rapidly in the past few years and became the fastest developing renewable energy technology. Small Permanent Magnet Synchronous Generators (PMSG’s) are widely used in low power wind turbines because they don’t need a gearbox and complicated control systems. In order to inject the electrical power generated by PMSG to the grid, an AC-DC-AC power electronic converter is required. A novel low cost efficient AC-DC converter is proposed to obtain the maximum power per ampere of PMSG. The new structure for the rectifier stage of the AC/AC converter is based on a DCM operated SEPIC converter and can convert the variable voltage and frequency of...
Shaking table test for assessing the seismic performance of semi-anchored steel water tanks
, Article Thin-Walled Structures ; Volume 176 , 2022 ; 02638231 (ISSN) ; Shahrouz Sotudeh, A ; Bakhshi, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The seismic responses of steel water tanks are unconventional given their complex dynamic behavior and the sources of nonlinearity. Therefore, providing a reliable, finite-element model is instrumental in better understanding their dynamic behavior and improving the design conditions. This paper aims to evaluate the seismic performance of steel water tanks using shaking table tests and provide a finite-element reference model for simulating real-size, semi-anchored water tanks by conducting a series of large-scale tests in the Shaking Table Lab of the Sharif University of Technology (SUT). Since scaling the tank requires a difficult process involving changing the liquid density, this paper...
Application of Tuned Mass Dampers in Controlling the Seismic Response of Anchored and Unanchored Steel Cylindrical Storage Tanks with Fixed Roof
, M.Sc. Thesis Sharif University of Technology ; Rahimzadeh Rofuei, Fayyaz (Supervisor)
Abstract
This research aims to study the applicability of tuned mass dampers (TMDs) in mitigating the seismic responses of cylindrical, fixed-roof steel storage tanks. The finite element models used in this study are prepared in ABAQUS/CAE 2017 and include a cylindrical tank with a diameter of 30 meters, height of 12 meters that contains water up to level 10.8 meters. Shell courses have been designed in accordance with API 650 seismic provisions. The considered TMDs are two slender cylindrical tanks with the same height as that of the main tank and a diameter of 3 meters, placed by the sides of the main tank symmetrically, and are attached to it using spring elements. To maximize the effect of TMDs...
Design of optimum vibration absorbers for a bus vehicle to suppress unwanted vibrations against harmonic and random road excitations
, Article Scientia Iranica ; Volume 28, Issue 1 , 2021 , Pages 241-254 ; 10263098 (ISSN) ; Moradi, H ; Sharif University of Technology
Sharif University of Technology
2021
Abstract
Unwanted vibrations of vehicles are regarded as harmful threats to human health in biomechanical and psychophysical terms. Road roughness is considered as the main cause of unwanted vibrations of bus vehicles. Vertical seat vibrations were found via simulating a 10-Degree-Of-Freedom (10-DOF) model of an intercity bus vehicle under harmonic and random excitations caused by road roughness. To suppress undesirable vibrations, mass-spring-damper passive absorbers were proposed in a 13-Degree-Of- Freedom (13-DOF) model of the bus. Following the optimization of the characteristics of embedded passive absorbers under each seat and implementation of the designed absorbers, the vertical displacement...
Encoding the information in relative parameters
, Article Physics Letters, Section A: General, Atomic and Solid State Physics ; Volume 407 , 2021 ; 03759601 (ISSN) ; Mani, A ; Sharif University of Technology
Elsevier B.V
2021
Abstract
We investigate the problem of communicating three parameters in the absence of shared reference frame. We explore two methods in which the relative angles of spins are used to encode the parameters. In the first method we use three spins that carry the information in their relative angles while in the second method we use three disjoint spin-pairs and the information is sent through the relative angles of each individual pair. We show that in the first method, the information conveyed by each qubit is more than the second one, and that is while it requires fewer particles. © 2021 Elsevier B.V
Generation of Quantum Correlation by the Environment
, M.Sc. Thesis Sharif University of Technology ; Memarzadeh, Laleh (Supervisor)
Abstract
In most of quantum information protocols, entanglement or, in general expression, quantum correlation, plays the major role. So it is very important to know the ways of generating entanglement and protecting it against noise.
In a general view, environment is usually known as a destructive agent for entangled states. Being exposed to environment, non-diagonal elements of an entangled state’s density matrix would tend to zero, because of decoherence effect. Thus, the entanglement would be disappear. But, recent studies have shown that, this destructive agent can be convert to a useful agent for generating entanglement between system components.
In this thesis, at first, the...
In a general view, environment is usually known as a destructive agent for entangled states. Being exposed to environment, non-diagonal elements of an entangled state’s density matrix would tend to zero, because of decoherence effect. Thus, the entanglement would be disappear. But, recent studies have shown that, this destructive agent can be convert to a useful agent for generating entanglement between system components.
In this thesis, at first, the...
Investigating the Response Modification Factor of 3-D Steel Braced/Moment-Resisting Frames with Irregularity in Plan
, M.Sc. Thesis Sharif University of Technology ; Khonsari, Vahid (Supervisor)
Abstract
Study of former earthquakes damages reveals that irregular structures are more susceptive to failure than regular ones. Irregular structures are classified into two categories, namely those with irregularity in elevation and the ones with irregularity in plan. Besides, one of the crucial parameters in working out the earthquake’s equivalent static load is response modification coefficient (R). Based on the type of seismic lateral force-resisting system, this parameter can have various values. In this research, using nonlinear static analysis, the response modification coefficient of a great number of 3-D steel frames of 5, 7 and 9 m spans and having 1 to 10 stories with various...
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
In recent years, the use of embedded processors has grown increasingly in wide range of computer systems; so that most of manufactured CPUs are used in emebedded systems many of which are safty-critical systems such as medical devices, aircraft flight control, space systems, nuclear systems, etc. The incidence of failure in these systems can cause irreversible damages on human life, financial or environmental matters. Silicon process technology trends, such as reducing the threshold voltage, increasing the frequency and decreasing the size of transistors, not only caused increase in single-bit fault rate but also caused occurance of multi-bit faults. Due to importance ofcorrect operation of...
Design of Robust Digital Circuits Against Soft Errors Considering Multiple Event Transients Fault (METs)
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
Nowadays, one of the most important challenges in the design of digital circuits is their susceptibility to the strike of high energy particles which leads to the Single Event Transient (SET) and Multiple Event Transients (MET). In fact, technology scaling which results in lower supply voltage, higher operating frequency, and lower nodal capacitance, makes today’s digital circuits more susceptible not only to high energy particles but also to low energy particles. Moreover emerging deep sub-micron technologies and the integration of more cells in today’s chips have caused higher probability of MET occurrences. A lot of research has tried to reduce the soft error rate due to high energy...
Design and Implementation of a Fault-Tolerant Routing Algorithm in WSNs
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
Wireless Sensor Networks (WSNs) are prone to faults due to battery depletion of nodes, where a node failure can disturb routing, as it plays a key role in transferring sensed data to the end users. A WSN may be partitioned into groups of nodes called clusters; for every cluster, there is a node, called Cluster Head (CH) that is responsible for collecting and transferring data from all nodes in that cluster. This means that the CH is a single point of failure; i.e., once a CH fails, the whole cluster will fail, which leads to inability of its members for transferring data outside the cluster. This thesis presents a Fault-Tolerant and Energy-Aware algorithm (FTEA), which prolongs the lifetime...
Fault-Tolerant Implementation of Erasure Codes for Storage Systems
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
The increasing size of valuable data emphasizes the importance of applying reliability in storage systems. One way to protect storage system failures is using erasure codes. The advantages of using erasure codes are their low overheads and high reliability. Soft errors caused by high-energetic particles do not only corrupt data in the SSD-based storage systems, but also in the erasure codes. In this regards, it is important to protect erasure code implementations against soft errors. This thesis proposes a fault-tolerant implementation of erasure codes. The proposed method is based on the structure of each erasure code. This method is analytically evaluated on four erasure codes, i.e....
Soft Error Rate Estimation in Presence of Multiple Event Transients (METs)
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
With continuous device down-scaling and increase in transistor counts on a chip, complementary metal-oxide-semiconductor (CMOS) technology has become extremely sensitive to soft errors. Soft errors are transient errors caused by energetic particles such as neutrons and alpha particles. An essential step to design a soft error tolerant digital system with minimal performance and power overheads is Soft Error Rate (SER) estimation of system components. Until recently, Single Event Upsets (SEUs) in latches and Filp-Flops (FFs) and Single Event Transients (SETs) in combinational logic parts of digital circuits were regarded as the main effects of particle strikes. However, with the emerging...
Design and Evaluation of a Master/Checker Method for an Embedded Processor
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
Ever increasing applications of embedded systems have motivated the designers to pay special attention to the design requirements of such systems. Among embedded applications, safety-critical systems have high reliability requirements as failures in such systems may endanger human life or result in catastrophic consequences. Embedded processors as the computation cores of embedded systems are very crucial from reliability point of view. This is because; a failure in the processor most probably leads to a system failure. One effective way to protect embedded processors against environmental faults is to use system level fault-tolerant techniques such as Master/Checker (M/C) or Triple Modular...
Design of Fault Tolerant Processor for Implementation on SRAM Based FPGAs
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
Vulnerability of SRAM-based FPGAs to soft errors signals the importance of applying fault-tolerant methods in FPGAs used in safety-critical applications. Previous methods to protect SRAM-based FPGAs impose significant area and power overheads. Additionally, they suffer from susceptibility of configuration bits to Single Event-Multiple Upsets (SEMU). This thesis presents a Highly Available Fault-Tolerant Architecture (HAFTA) to protect SRAM-based FPGA designs against SEMUs in both configuration and user bits. In HAFTA, the entire design is duplicated and the main and replica flip-flops are compared at each clock cycle to detect any possible mismatch. To save the latest correct state of the...
Design of Fault-tolerance Mechanisms for Soft Multiprocessors
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
Increasing complexity of embedded systems and the need for more computation powerhave directed designers toward using of multiprocessors. SRAM-based FPGAs are suitable platforms for implementation of multiprocessors due to thier low cost, fast time-to-market and re-configurability. FPGA-based multiprocessors are known as soft multiprocessors. The large area of SRAM-based FPGAs is occupied by configuration bits. Configuration bits are vulnerable to high energy particles that can lead to soft errors. In this regards, it is of decisive importance to protect soft multiprocessors against soft errors. This thesis proposes a fault-tolerant method for soft multiprocessors that can detect and...
Reliability Enhancement of SSD-based Storage Systems Using Erasure Codes
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
The use of flash-based Solid State Disks (SSDs) has been increased in the past decades because of their high performance and low power consumption. As SSDs have no moving mechanical parts, they are more reliable than HDDs. SSDs have specific errors, such as read, program, and erase disturbs, data retention, and endurance. It is so common in storage systems to apply an array of disks called Redundant Array of Independent Disks (RAID) together for the aim of reliability and performance. Erasure codes are one of the main methods applied in storage systems for the aim of reliability. Erasure codes increase the reliability of storage systems by protecting them against disk failures and sector...
Reliability Improvement of On-chip Memories
, Ph.D. Dissertation Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
Reliability, performance, and energy consumption are among the most important constraints that should be satisfied in modern processors design. More than 60% of the chip area is occupied by on-chip SRAM memories and they not only contribute in a large fraction of energy consumption, but also are the most error-prone components. Radiation-induced soft errors in on-chip memories are a major concern in modern processors design. Although Single Event Upsets (SEUs) have been known to be the main concern regarding SRAM memory reliability over the past decades, with the continued downscaling of technology, the occurrence rate of Multiple-Bit Upsets (MBUs) is comparable to that of SEUs in today’s...
Reliability Improvement in Network on Chips against Crosstalk Fault Considering Five-Wire Latency Model
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
One of the major challenges that threat the reliability of NoC-based systems is Crosstalk fault. Some effects of crosstalk fault such as Rising/falling delays and rising/falling speed-ups lead to the variations in channel delay, incorrect data transmission, and extra power consumption in NoC communication channels. Crosstalk fault is data dependent and the intensity of this fault seriously depends on the transition patterns appearing on the wire during the data traversal between processing elements. Most of mechanisms tackling crosstalk fault that are discussed in literature are based on 3-wire delay model. In 3-wire delay model, one wire is considered as victim wire and classification of...
Crosstalk Fault Treatment in NoCs Using Data Manipulation
, Ph.D. Dissertation Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
Recent advances in Very-Large-Scale Integration (VLSI) technologies have enabled designers to integrate a large number of Processing Elements (PEs) on a single die. According to International Technology Roadmap for Semiconductors (ITRS), the number of PEs will reach 5000 on a single die in 2021. Although the main achievements of such rapid advancement in chips are high processing speed, shrinkage of technology size has made chips highly sensitive to different challenges. Networks on chip (NoCs), as an example of these systems, are not exempted from these challenges. Crosstalk fault is one of the major fault resources in NoCs. Crosstalk faults occur due to coupling capacitances between...
Designing and Implementing a Cluster-based Energy-aware Routing Algorithm for Wireless Sensor Network
, M.Sc. Thesis Sharif University of Technology ; Miremadi, Ghasem (Supervisor)
Abstract
Wireless Sensor Networks (WSNs) consist of sensor nodes that are connected to each other and are widely used in many applications to acquire and process information. WSN nodes are battery powered, therefore energy management is a key factor for long live network. Node radio transceiver unit uses the most part of energy resource of the node and as a result limits the network lifetime. One way to prolong lifetime of network is to utilize routing protocols to manage energy consumption. To have an energy efficient protocol, we can apply cluster organization on the network, where sensor nodes are partitioned into groups called cluster. Then, the whole cluster data is sent through Cluster Head...