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Flutter Analysis Rotating Blade of a Turbo Machinery Made of Magneto Rheological Elastomer Core
, M.Sc. Thesis Sharif University of Technology ; Haddadpour, Hassan (Supervisor)
Abstract
This study considers the flutter analysis rotating blade of a turbo machinery made of magneto rheological elastomer core. The Smith theory is used for modeling the compressible subsonic flow. The classical Hamilton’s principle along with the assume mode method is used to set up the equations of motion. The validity of the derived formulation is confirmed through comparison with those obtained from the finite element software and the available results in the literature. Various parametric studies including the effects of applied magnetic field, core layer thicknesses, rotating speed, setting angle are examined for considered configuration of the rotating blade. The results show that the first...
O-TF and O-FTF, optical fault-tolerant DCNS
, Article Proceedings - 26th Euromicro International Conference on Parallel, Distributed, and Network-Based Processing, PDP 2018 ; 6 June , 2018 , Pages 639-642 ; 9781538649756 (ISBN) ; Koohi, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Performance of a data center is a function of three features; bandwidth, latency, and reliability. By adopting optical technology in data center network, bandwidth increment, in addition to reduction of transmission latency and power consumption, is achieved. Unfortunately, fault tolerance of the optical networks has raised less attention so far. So in this paper, we propose a fault-tolerant, scalable, and high-performance optical architecture built upon previously proposed O-TF network, with the goal of redundancy optimization and reducing the minimum number of wavelength channels required for non-blocking functionality of the network. Moreover, reducing network diameter, in O-FTF network...
Exploitation of wavelength, hardware, and path redundancies in fault-tolerant all-optical DCNs
, Article Optical Fiber Technology ; Volume 51 , 2019 , Pages 77-89 ; 10685200 (ISSN) ; Koohi, S ; Sharif University of Technology
Academic Press Inc
2019
Abstract
Data center performance is affected by three main factors; bandwidth, latency, and reliability of intra-data center interconnection network. Bandwidth and latency are definitely improved by adopting optical technology for intra-data center communication, but fault tolerance of the corresponding optical networks has been raised less. Recently, we introduced two Torus-based, all-optical, and non-blocking networks, i.e. O-TF and O-FTF, addressing reliability of optical networks, and now, in this paper, to address the scalability problem, we propose a novel Optical Clos-based architecture which reduces minimum number of required wavelength channels, as well as, the switch size in each node....
Effects of magnetoelastic loads on free vibration characteristics of the magnetorheological-based sandwich beam
, Article Journal of Intelligent Material Systems and Structures ; Volume 31, Issue 7 , 2020 , Pages 1015-1028 ; Shahali, P ; Haddadpour, H ; Sharif University of Technology
SAGE Publications Ltd
2020
Abstract
In this contribution, we have investigated the effects of magnetoelastic loads on free vibration characteristics of the magnetorheological-based sandwich beam. The considered sandwich beam consists of a magnetorheological core with elastic top and base layers. For these means, the structural governing equations are derived using the Hamilton principle and solved by the finite element method. The results are validated in comparison with the existing results in the literature. The effects of variation in the parameters such as magnetic field intensity and the thickness of the core and top layers on the deviation of the first natural frequency and the corresponding loss factor are studied as...
HELIOS: High-speed sequence alignment in optics
, Article PLoS Computational Biology ; Volume 18, Issue 11 , 2022 ; 1553734X (ISSN) ; Akbari Rokn Abadi, S ; Koohi, S ; Sharif University of Technology
Public Library of Science
2022
Abstract
In response to the imperfections of current sequence alignment methods, originated from the inherent serialism within their corresponding electrical systems, a few optical approaches for biological data comparison have been proposed recently. However, due to their low performance, raised from their inefficient coding scheme, this paper presents a novel all-optical high-throughput method for aligning DNA, RNA, and protein sequences, named HELIOS. The HELIOS method employs highly sophisticated operations to locate character matches, single or multiple mutations, and single or multiple indels within various biological sequences. On the other hand, the HELIOS optical architecture exploits...
WalkIm: Compact image-based encoding for high-performance classification of biological sequences using simple tuning-free CNNs
, Article PLoS ONE ; Volume 17, Issue 4 April , 2022 ; 19326203 (ISSN) ; Mohammadi, A ; Koohi, S ; Sharif University of Technology
Public Library of Science
2022
Abstract
The classification of biological sequences is an open issue for a variety of data sets, such as viral and metagenomics sequences. Therefore, many studies utilize neural network tools, as the well-known methods in this field, and focus on designing customized network structures. However, a few works focus on more effective factors, such as input encoding method or implementation technology, to address accuracy and efficiency issues in this area. Therefore, in this work, we propose an image-based encoding method, called as WalkIm, whose adoption, even in a simple neural network, provides competitive accuracy and superior efficiency, compared to the existing classification methods (e.g. VGDC,...
KDeep: a new memory-efficient data extraction method for accurately predicting DNA/RNA transcription factor binding sites
, Article Journal of Translational Medicine ; Volume 21, Issue 1 , 2023 ; 14795876 (ISSN) ; Tabatabaei, F ; Koohi, S ; Sharif University of Technology
BioMed Central Ltd
2023
Abstract
This paper addresses the crucial task of identifying DNA/RNA binding sites, which has implications in drug/vaccine design, protein engineering, and cancer research. Existing methods utilize complex neural network structures, diverse input types, and machine learning techniques for feature extraction. However, the growing volume of sequences poses processing challenges. This study introduces KDeep, employing a CNN-LSTM architecture with a novel encoding method called 2Lk. 2Lk enhances prediction accuracy, reduces memory consumption by up to 84%, reduces trainable parameters, and improves interpretability by approximately 79% compared to state-of-the-art approaches. KDeep offers a promising...
A new profiling approach for DNA sequences based on the nucleotides' physicochemical features for accurate analysis of SARS-CoV-2 genomes
, Article BMC Genomics ; Volume 24, Issue 1 , 2023 ; 14712164 (ISSN) ; Mohammadi, A ; Koohi, S ; Sharif University of Technology
BioMed Central Ltd
2023
Abstract
Background: The prevalence of the COVID-19 disease in recent years and its widespread impact on mortality, as well as various aspects of life around the world, has made it important to study this disease and its viral cause. However, very long sequences of this virus increase the processing time, complexity of calculation, and memory consumption required by the available tools to compare and analyze the sequences. Results: We present a new encoding method, named PC-mer, based on the k-mer and physic-chemical properties of nucleotides. This method minimizes the size of encoded data by around 2 k times compared to the classical k-mer based profiling method. Moreover, using PC-mer, we designed...
Designing a Fault tolerant Optical Interconnection Network for Data Centers
, M.Sc. Thesis Sharif University of Technology ; Koohi, Somayyeh (Supervisor)
Abstract
Data center performance is a function of three features; bandwidth, latency, and reliability. The issue of increasing bandwidth and reducing power consumption for scalability is one of the things that can be accessed with optical technology and it has been used in recent designs. However, the problem of fault tolerance and dealing with failures in optical interconnection networks have been raised less. Data center failures fall into two categories of links and switches. The design of these networks is mainly done at two levels: the hardware design and the design of routing methods. Also, some parts may be added to control and establish connections between the routing and network hardware...
Biological Sequences Comparison Based on Optical Processing
, Ph.D. Dissertation Sharif University of Technology ; Koohi, Somayyeh (Supervisor)
Abstract
Biological sequences, such as DNA, RNA, and proteins, contain vital information and activities of living organisms. Any changes or mutations in these sequences can alter the structure of proteins, which are the basis of all cell activities. This can cause disruptions in cellular functions. With advancements in cell data extraction technology, the amount of genetic data has increased, leading to a need for efficient methods to identify and study mutations. One of the primary tools for this work is biological sequence comparators. Despite the different types of sequence comparators available, there is still a need for an algorithm that is fast, accurate, scalable, and uses few resources....
Dynamic stability analysis of a sandwich beam with magnetorheological elastomer core subjected to a follower force
, Article Acta Mechanica ; Volume 231, Issue 9 , 2020 , Pages 3715-3727 ; Yousefi, M ; Haddadpour, H ; Sadeghmanesh, M ; Sharif University of Technology
Springer
2020
Abstract
In the present study, the effect of using magnetorheological elastomer materials and a magnetic field on the dynamic stability of a sandwich beam under a follower force has been investigated for various boundary conditions. The considered sandwich beam consists of a magnetorheological elastomer core constrained by elastic layers. The structural governing equations are derived using Hamilton’s principle and solved by the finite element method. The validity of the result is examined by comparison with those in the literature. The effects of variation in the parameters such as magnetic field intensity and the thickness of the layers on the stability of the sandwich beam are studied. Finally,...
Optical pattern generator for efficient bio-data encoding in a photonic sequence comparison architecture
, Article PLoS ONE ; Volume 16, Issue 1 , 2021 ; 19326203 (ISSN) ; Dijujin, N. H ; Koohi, S ; Sharif University of Technology
Public Library of Science
2021
Abstract
In this study, optical technology is considered as SA issues’ solution with the potential ability to increase the speed, overcome memory-limitation, reduce power consumption, and increase output accuracy. So we examine the effect of bio-data encoding and the creation of input images on the pattern-recognition error-rate at the output of optical Vander-lugt correlator. Moreover, we present a genetic algorithm-based coding approach, named as GAC, to minimize output noises of cross-correlating data. As a case study, we adopt the proposed coding approach within a correlation-based optical architecture for counting k-mers in a DNA string. As verified by the simulations on Salmonella whole-genome,...
Optical pattern generator for efficient bio-data encoding in a photonic sequence comparison architecture
, Article PloS one ; Volume 16, Issue 1 , 2021 , Pages e0245095- ; 19326203 (ISSN) ; Hashemi Dijujin, N ; Koohi, S ; Sharif University of Technology
NLM (Medline)
2021
Abstract
In this study, optical technology is considered as SA issues' solution with the potential ability to increase the speed, overcome memory-limitation, reduce power consumption, and increase output accuracy. So we examine the effect of bio-data encoding and the creation of input images on the pattern-recognition error-rate at the output of optical Vander-lugt correlator. Moreover, we present a genetic algorithm-based coding approach, named as GAC, to minimize output noises of cross-correlating data. As a case study, we adopt the proposed coding approach within a correlation-based optical architecture for counting k-mers in a DNA string. As verified by the simulations on Salmonella whole-genome,...
Optical pattern generator for efficient bio-data encoding in a photonic sequence comparison architecture
, Article PLoS ONE ; Volume 16, Issue 1 January 2021 , 2021 ; 19326203 (ISSN) ; Dijujin, N. H ; Koohi, S ; Sharif University of Technology
Public Library of Science
2021
Abstract
In this study, optical technology is considered as SA issues’ solution with the potential ability to increase the speed, overcome memory-limitation, reduce power consumption, and increase output accuracy. So we examine the effect of bio-data encoding and the creation of input images on the pattern-recognition error-rate at the output of optical Vander-lugt correlator. Moreover, we present a genetic algorithm-based coding approach, named as GAC, to minimize output noises of cross-correlating data. As a case study, we adopt the proposed coding approach within a correlation-based optical architecture for counting k-mers in a DNA string. As verified by the simulations on Salmonella whole-genome,...
Optical pattern generator for efficient bio-data encoding in a photonic sequence comparison architecture
, Article PloS one ; Volume 16, Issue 1 , 2021 , Pages e0245095- ; 19326203 (ISSN) ; Hashemi Dijujin, N ; Koohi, S ; Sharif University of Technology
NLM (Medline)
2021
Abstract
In this study, optical technology is considered as SA issues' solution with the potential ability to increase the speed, overcome memory-limitation, reduce power consumption, and increase output accuracy. So we examine the effect of bio-data encoding and the creation of input images on the pattern-recognition error-rate at the output of optical Vander-lugt correlator. Moreover, we present a genetic algorithm-based coding approach, named as GAC, to minimize output noises of cross-correlating data. As a case study, we adopt the proposed coding approach within a correlation-based optical architecture for counting k-mers in a DNA string. As verified by the simulations on Salmonella whole-genome,...
Aeroelastic analysis of a sandwich panel with partially treated magneto-rheological fluid core
, Article Journal of Intelligent Material Systems and Structures ; Volume 30, Issue 1 , 2019 , Pages 140-154 ; 1045389X (ISSN) ; Rayyat Rokn Abadi, M ; Yousefi, M ; Haddadpour, H ; Sharif University of Technology
SAGE Publications Ltd
2019
Abstract
This study considers the aeroelastic instability of a partially treated magneto-rheological fluid sandwich panel in supersonic airflow. The linear first-order piston theory is used for modeling the aerodynamic pressure. Using classical Hamilton’s principle along with the finite element method, the equations of motion are derived. The critical value of the non-dimensional aerodynamic pressure is obtained by traditional p-method scheme. The validity of the finite element formulation is examined through comparison with those obtained from the assumed mode formulation and the available results in the literature. Various parametric studies including the effects of applied magnetic field, core and...
Aeroelastic analysis of a sandwich panel with partially treated magneto-rheological fluid core
, Article Journal of Intelligent Material Systems and Structures ; Volume 30, Issue 1 , 2019 , Pages 140-154 ; 1045389X (ISSN) ; Rayyat Rokn Abadi, M ; Yousefi, M ; Haddadpour, H ; Sharif University of Technology
SAGE Publications Ltd
2019
Abstract
This study considers the aeroelastic instability of a partially treated magneto-rheological fluid sandwich panel in supersonic airflow. The linear first-order piston theory is used for modeling the aerodynamic pressure. Using classical Hamilton’s principle along with the finite element method, the equations of motion are derived. The critical value of the non-dimensional aerodynamic pressure is obtained by traditional p-method scheme. The validity of the finite element formulation is examined through comparison with those obtained from the assumed mode formulation and the available results in the literature. Various parametric studies including the effects of applied magnetic field, core and...
Effect of temperature and magnetoelastic loads on the free vibration of a sandwich beam with magnetorheological core and functionally graded material constraining layer
, Article Acta Mechanica ; Volume 233, Issue 11 , 2022 , Pages 4939-4959 ; 00015970 (ISSN) ; Shams, S ; Kazemi, M. R ; Rokn Abadi, M ; Sharif University of Technology
Springer
2022
Abstract
In this paper, we investigate the effects of temperature and magnetoelastic load, on the free vibration of an elastomer sandwich beam with magnetorheological (MR) core and functionally graded material (FGM) constraining lamina under high temperature environment. This sandwich beam is named FGMR beam in this paper. The material properties of the functionally graded material layers are assumed to be temperature-dependent and vary continuously through-the-thickness according to a simple power-law distribution in terms of the volume fractions of the constituents. Also, it is assumed that the beam may be clamped, hinged, or free at its ends and is subjected to one-dimensional steady-state heat...
An accurate alignment-free protein sequence comparator based on physicochemical properties of amino acids
, Article Scientific Reports ; Volume 12, Issue 1 , 2022 ; 20452322 (ISSN) ; Abdosalehi, A. S ; Pouyamehr, F ; Koohi, S ; Sharif University of Technology
Nature Research
2022
Abstract
Bio-sequence comparators are one of the most basic and significant methods for assessing biological data, and so, due to the importance of proteins, protein sequence comparators are particularly crucial. On the other hand, the complexity of the problem, the growing number of extracted protein sequences, and the growth of studies and data analysis applications addressing protein sequences have necessitated the development of a rapid and accurate approach to account for the complexities in this field. As a result, we propose a protein sequence comparison approach, called PCV, which improves comparison accuracy by producing vectors that encode sequence data as well as physicochemical properties...
, M.Sc. Thesis Sharif University of Technology ; Akhavan, Mohammad (Supervisor)
Abstract
The most important researchers’ purposes in superconductivity are achievement of the room temperature superconductivity and to understand the high temperature superconductivity mechanism. Researchers’ goal in to increase the transition temperature by applying pressure, changing oxygen content, different doping, and changing stoichiometry in the families of the high temperature superconductors. In this research, which has been carried out in the Magnet Research Laboratary of Sharif University of Technology, samples of Y3Ba5Cu8O18, Gd3Ba5Cu8O18, and Pr3Ba5Cu8O18 have been synthesized by the standard solid-state reaction technique, the structure, electrical and magnetic properties of the...