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A proper power ratio selection for electric and combustion motors in hybrid parallel electric vehicles
, Article International Review of Automatic Control ; Volume 8, Issue 4 , 2015 , Pages 272-280 ; 19746059 (ISSN) ; Ebrahimi, S ; Safaeian, R ; Oraee, H ; Sharif University of Technology
Praise Worthy Prize
2015
Abstract
Determining the power ratio of the electric motor to the total power in parallel hybrid electric vehicles is of great importance that has a major impact on electric vehicle performance. The so-called Hybridization Factor is selected based on the desired performance indices of the vehicle. In practice, the effect of hybridization factor is observable on all the main indices of vehicle performance such as maximum speed, gradeability, pollutant emission, fuel consumption, etc. This ratio should be determined considering the desired performance indices and priorities. In this paper, the performance of an example electric vehicle is investigated through simulation results in ADVISOR software...
Analyzing and design of mesh ribbon cathodic protection for aboveground storage tanks
, Article South African Journal of Chemical Engineering ; Volume 45 , 2023 , Pages 51-59 ; 10269185 (ISSN) ; Sharifi, R ; Dolati, A ; Medhat, S ; Sharif University of Technology
Elsevier B.V
2023
Abstract
Aboveground storage tanks are widely used for storage of liquids. The bottom of these tanks rest on the soil and is prone to the corrosion. Due to the use of geo-membrane liner in some cases, the bottoms of these tanks can only be protected from corrosion by using distributed mesh ribbon anodes. Up to now, there is no an accurate and comprehensive calculation for current distribution in such configurations. For this reason, the spans of the ribbon anodes and conductor bars are mostly chose based on simple and handy formulas, which may not be correct and optimum enough. Therefore, in this paper, the current distribution is calculated based on a 2D model and considering coating and...
Study of HVDC Transmission for Offshore Wind Farms Based on Voltage Source Converters
, M.Sc. Thesis Sharif University of Technology ; Parniani, Mostafa (Supervisor)
Abstract
In this thesis, DC transmission of offshore wind farms is studied thoroughly. Various system configurations that are introduced in the literatures are discussed and their control scheme for normal conditions and grid faults are studied. Then, the HVDC transmission based on voltage source converter, located between a local offshore ac grid and the onshore ac system is investigated as the most practical choice. The HVDC linke circuit elements are calculated and the control strategies of the offshore and onshore converters are introduced. DFIGs are considered to be the best choice for the offshore wind turbine generators. Then, the system is simulated and the frequency of the offshore grid is...
Design and Implementation of a Tunable Frequency Channelizer on FPGA
, M.Sc. Thesis Sharif University of Technology ; Tabandeh, Mahmoud (Supervisor)
Abstract
Nowdays, many of communication systems working together. The fist part of each communication system is related to separating a desired part of system input signal. This is called channelisation. Channelization is a process where single, few, or all channels from a certain frequency band are separated for further processing. The separation of single channel is usually done by down-conversion followed by filtering and optional sample-rate conversion. A straightforward implementation for multi channel sepration, which is also the traditional implementation of wideband channelizer, is to simply use a single-channel channelizer for each channel. A few applications require that an input signal be...
Performance improvement of steady-state and transient operation of offshore wind farm HVDC power transmission
, Article 2015 IEEE 16th Workshop on Control and Modeling for Power Electronics, COMPEL 2015, 12 July 2015 through 15 July 2015 ; July , 2015 , Page(s): 1 - 7 ; 9781467368476 (ISBN) ; Ebrahimi, S ; Parniani, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Wind power generation is increasing fast as a clean renewable energy resource. Offshore wind farms are popular due to advantages such as higher and smoother wind speeds, less farm site limitations, etc. High capacitive currents and need to expensive compensations, make use of high-voltage-direct-current (HVDC) power transmission indispensable for longdistance wind farm power generations. Steady-state and transient performance improvements of HVDC systems have always been an interesting industrial and academic research area. In this paper, a novel control method is proposed to improve the steady-state operation of HVDC system. Moreover, a new fault detection scheme is proposed to improve the...
Fast causal orientation learning in directed acyclic graphs
, Article International Journal of Approximate Reasoning ; Volume 153 , 2023 , Pages 49-86 ; 0888613X (ISSN) ; Salehkaleybar, S ; Tabandeh, M ; Sharif University of Technology
Elsevier Inc
2023
Abstract
Causal relationships among a set of variables are commonly represented by a directed acyclic graph. The orientations of some edges in the causal DAG can be discovered from observational/interventional data. Further edges can be oriented by iteratively applying so-called Meek rules. Inferring edges' orientations from some previously oriented edges, which we call Causal Orientation Learning (COL), is a common problem in various causal discovery tasks. In these tasks, it is often required to solve multiple COL problems and therefore applying Meek rules could be time consuming. Motivated by Meek rules, we introduce Meek functions that can be utilized in solving COL problems. In particular, we...
Experiment Design for Causal Discovery Based on the Observational/Interventional Data
, Ph.D. Dissertation Sharif University of Technology ; Tabandeh, Mahmoud (Supervisor) ; Saleh Kalibar, Saber (Supervisor)
Abstract
In numerous scientific disciplines, analyzing a system often fails to reveal significant relationships between its various variables. However, in certain instances, changes in one variable can influence the behavior of one or more other variables. Systems where such underlying causal relationships exist are referred to as causal systems. The process of inferring the structure of these systems is known as causal learning. In causal learning, given observed samples from a system and under certain assumptions, the joint distribution of the variables can determine the equivalence class of their corresponding graphical model. Once the equivalence class is identified, interventions are employed to...
Network vulnerability analysis through vulnerability take-grant model (VTG)
, Article 7th International Conference on Information and Communications Security, ICICS 2005, Beijing, 10 December 2005 through 13 December 2005 ; Volume 3783 LNCS , 2005 , Pages 256-268 ; 03029743 (ISSN); 3540309349 (ISBN); 9783540309345 (ISBN) ; Sadoddin, R ; Jalili, R ; Zakeri, R ; Omidian, A. R ; Sharif University of Technology
2005
Abstract
Modeling and analysis of information system vulnerabilities helps us to predict possible attacks to networks using the network configuration and vulnerabilities information. As a fact, exploiting most of vulnerabilities result in access rights alteration. In this paper, we propose a new vulnerability analysis method based on the Take-Grant protection model. We extend the initial Take-Grant model to address the notion of vulnerabilities and introduce the vulnerabilities rewriting rules to specify how the protection state of the system can be changed by exploiting vulnerabilities. Our analysis is based on a bounded polynomial algorithm, which generates the closure of the Take-Grant graph...
Sequence dependence of the binding energy in chaperone-driven polymer translocation through a nanopore
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 83, Issue 1 , January , 2011 ; 15393755 (ISSN) ; Ejtehadi, M. R ; Metzler, R ; Sharif University of Technology
2011
Abstract
We study the translocation of stiff polymers through a nanopore, driven by the chemical-potential gradient exerted by binding proteins (chaperones) on the trans side of the pore. Bound chaperones prevent backsliding through the pore and, therefore, partially rectify the polymer passage. We show that the sequence of chain monomers with different binding affinity for the chaperones significantly affects the translocation dynamics. In particular, we investigate the effect of the nearest-neighbor adjacency probability of the two monomer types. Depending on the magnitude of the involved binding energies, the translocation speed may either increase or decrease with the adjacency probability. We...
First passage time distribution of chaperone driven polymer translocation through a nanopore: Homopolymer and heteropolymer cases
, Article Journal of Chemical Physics ; Volume 135, Issue 24 , 2011 ; 00219606 (ISSN) ; Metzler, R ; Ejtehadi, M. R ; Sharif University of Technology
2011
Abstract
Combining the advection-diffusion equation approach with Monte Carlo simulations we study chaperone driven polymer translocation of a stiff polymer through a nanopore. We demonstrate that the probability density function of first passage times across the pore depends solely on the Péclet number, a dimensionless parameter comparing drift strength and diffusivity. Moreover it is shown that the characteristic exponent in the power-law dependence of the translocation time on the chain length, a function of the chaperone-polymer binding energy, the chaperone concentration, and the chain length, is also effectively determined by the Péclet number. We investigate the effect of the chaperone size on...
Reply: Abedpour, asgari, and tabar
, Article Physical Review Letters ; Volume 106, Issue 20 , 2011 ; 00319007 (ISSN) ; Asgari, R ; Tabar, M. R. R ; Sharif University of Technology
2011
Irreversibility in response to forces acting on graphene sheets
, Article Physical Review Letters ; Volume 104, Issue 19 , May , 2010 ; 00319007 (ISSN) ; Asgari, R ; Tabar, M. R. R ; Sharif University of Technology
2010
Abstract
The amount of rippling in graphene sheets is related to the interactions with the substrate or with the suspending structure. Here, we report on an irreversibility in the response to forces that act on suspended graphene sheets. This may explain why one always observes a ripple structure on suspended graphene. We show that a compression-relaxation mechanism produces static ripples on graphene sheets and determine a peculiar temperature Tc, such that for T
Analysis of design goals of cryptography algorithms based on different components
, Article Indonesian Journal of Electrical Engineering and Computer Science ; Volume 23, Issue 1 , 2021 , Pages 540-548 ; 25024752 (ISSN) ; Aref, M. R ; Khorshiddoust, R. R ; Sharif University of Technology
Institute of Advanced Engineering and Science
2021
Abstract
Cryptography algorithms are a fundamental part of a cryptographic system that is designed and implemented to increase information security. They are the center of attention of experts in the information technology domains. Although the cryptography algorithms are implemented to attain the goals such as confidentially, integrity, and authenticity of designing, but other matters that must be noticed by designers include speed, resource consumption, reliability, flexibility, usage type, and so on. For the useful allocation of hardware, software, and human resources, it is important to identify the role of each of the factors influencing the design of cryptographic algorithms to invest in the...
Conservation of statistical results under the reduction of pair-contact interactions to solvation interactions
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 72, Issue 6 , 2005 ; 15393755 (ISSN) ; Farzami, R. R ; Ejtehadi, M. R ; Sharif University of Technology
2005
Abstract
We show that the hydrophobicity of sequences is the leading term in Miyazawa-Jernigan interactions. Being the source of additive (solvation) terms in pair-contact interactions, they were used to reduce the energy parameters while resulting in a clear vector manipulation of energy. The reduced (additive) potential performs considerably successful in predicting the statistical properties of arbitrary structures. The evaluated designabilities of the structures by both models are highly correlated. Suggesting geometrically nondegenerate vectors (structures) as proteinlike structures, the additive model is a powerful tool for protein design. Moreover, a crossing point in the log-linear diagram of...
Multifunctional hyperelastic structured surface for tunable and switchable transparency
, Article Applied Sciences (Switzerland) ; Volume 11, Issue 5 , 2021 , Pages 1-11 ; 20763417 (ISSN) ; Goudarzi, T ; Fleury, R ; Naghdabadi, R ; Sharif University of Technology
MDPI AG
2021
Abstract
We leverage the crucial hyperelastic properties of a multifunctional structured surface to optimize the reconfigurability of the electromagnetic transmission under large nonlinear mechanical deformations. This multiphysics, multifunctional, hyperelastic structured surface (HSS) offers two simultaneous intriguing functionalities; tunability and switchability. It is made of copper reso-nators and a Polydimethylsiloxane (PDMS) substrate, which is one of the most favorable deformable substrates due to its hyperelastic behavior. The proposed HSS is fabricated via an original cost-effective technique and the multiphysics functionalities are captured in both experimental tests and numerical...
MaxHiC: A robust background correction model to identify biologically relevant chromatin interactions in Hi-C and capture Hi-C experiments
, Article PLoS Computational Biology ; Volume 18, Issue 6 , 2022 ; 1553734X (ISSN) ; Modegh, R. G ; Rabiee, H. R ; Sarbandi, E. R ; Rezaie, N ; Tam, K. T ; Forrest, A. R. R ; Sharif University of Technology
Public Library of Science
2022
Abstract
Hi-C is a genome-wide chromosome conformation capture technology that detects interactions between pairs of genomic regions and exploits higher order chromatin structures. Conceptually Hi-C data counts interaction frequencies between every position in the genome and every other position. Biologically functional interactions are expected to occur more frequently than transient background and artefactual interactions. To identify biologically relevant interactions, several background models that take biases such as distance, GC content and mappability into account have been proposed. Here we introduce MaxHiC, a background correction tool that deals with these complex biases and robustly...
SER of M-PSK modulation in incremental-selective decode-and-forward cooperative communications over Rayleigh fading channels
, Article International Conference on Advanced Communication Technology, ICACT, 13 February 2011 through 16 February 2011 ; February , 2011 , Pages 432-437 ; 17389445 (ISSN) ; 9788955191554 (ISBN) ; Saadat, R ; Aref, M. R ; Mirjalily, G ; Sharif University of Technology
2011
Abstract
In this paper we consider a cooperative communication systems over Rayleigh fading channels. The system utilizes a combination of incremental and selective decode-and-forward (ISDF) relaying protocols. The symbol error rate (SER) of M-PSK modulation for the ISDF protocol is derived. Using an approximation of the SER expression, the optimal power allocation is investigated. In order to reduce the complexity of the receiver, we used a modified version of the ISDF protocol which does not use the storage or retransmission of the first phase signal. We also derived optimal power allocation coefficient for modified ISDF. It has been noted that for the optimal power allocation in the ISDF protocol,...
Power allocation for incremental-selective decode-and-forward cooperative communications over Rician fading channels
, Article International Conference on Advanced Communication Technology, ICACT, 13 February 2011 through 16 February 2011 ; February , 2011 , Pages 730-734 ; 17389445 (ISSN) ; 9788955191554 (ISBN) ; Saadat, R ; Aref, M. R ; Mirjalily, G ; Sharif University of Technology
2011
Abstract
In this paper we consider a relaying communication system over Rician fading channels. In this system we assume simple Incremental-Selective Decode-and-Forward (ISDF) protocol, which is jointly combining incremental and selective DF relaying protocols. In this protocol, storage or retransmission of the first phase signal are not allowed. We analyze the symbol error rate (SER) performance of the recommended protocol with M-PSK modulation. We evaluate the performance of the protocol in the frequency nonselective slow Rician fading channels. Using the approximation of the SER expression, the optimal power allocation is investigated. Our results show that at least 50% of total power must be used...
Efficient and practical protocol for silylation of hydroxyl groups using reusable lithium perchlorate dispread in silica gel under neutral condition [electronic resource]
, Article Journal of Organometallic Chemistry ; 2006, Volume 691, Issue 5, Pages 817–820 ; Yousefi, R ; Saidi, M. R ; Sharif University of Technology
Abstract
A very efficient and mild procedure for the trimethylsilylation of a wide variety of alcohols, including primary, allylic, benzylic, secondary, hindered secondary, tertiary, and phenols with hexamethyldisilazane on the surface of silica gel dispersed with LiClO4 in room temperature at few minutes in excellent yields under neutral conditions is reported. This procedure also allows the excellent selectivity under LP-SiO2 system for silylation of alcohols in the presence of amine and phenolic hydroxy groups
Modeling, estimation, and model predictive control for Covid-19 pandemic with finite security duration vaccine
, Article 30th International Conference on Electrical Engineering, ICEE 2022, 17 May 2022 through 19 May 2022 ; 2022 , Pages 78-83 ; 9781665480871 (ISBN) ; Baghbadorani, R. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
Spreading Covid19 has significantly impacted humans' affairs worldwide, either economically or in a sanitary manner. Besides social distance and hospitalization, making and introducing different vaccines help us ameliorate infection and mortality rates. In this research, we use a nonlinear dynamic model for Covid19, with eight states named susceptible, exposed, infected, quarantined, hospitalized, recovered, deceased, and insusceptible populations. Also, we use social distancing, hospitalization, and vaccination rate as three control inputs. This research aims to stop the Covid-19 from spreading worldwide and minimize exposed, infected and deceased populations using model predictive control....