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khoshouei-esfahani--samin-sadat
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Physical Modeling of Vegetated Slopes to Investigate Unsaturated Flow Regimes and Slope Stability under Varying Inclination Angles
, M.Sc. Thesis Sharif University of Technology ; Sadeghi, Hamed (Supervisor)
Abstract
Rainfall is one of the primary factors contributing to slope instability, as it alters the hydraulic and mechanical properties of soil. Infiltration reduces matric suction, thereby decreasing shear strength and increasing the possibility of rainfall-induced landslides. Vegetation influences slope stability through both hydrological and mechanical reinforcement mechanisms by modifying suction and enhancing cohesion. Consequently, the stability of rainfall-triggered slopes depends on multiple factors, including initial slope conditions, rainfall intensity and duration, soil type, groundwater conditions, slope geometry, and vegetation cover. Root absorbed water reduces soil moisture and...
Analysis and Improvement of The Low-Voltage Ride Through Capability of Permanent-Magnet Synchronous Generator-Based Wind Turbines
, M.Sc. Thesis Sharif University of Technology ; Parniani, Mostafa (Supervisor)
Abstract
Permanent-magnet synchronous generators have attracted more attention in recent years due to their special advantages which make them a suitable option for variable-speed wind turbines.Low-voltage ride through capability is one of the main concerns in widespread use of wind turbines in electric grids. Nowadays wind turbines are expected to remain connected to the grid during voltage dips and support the voltage recovery process by supplying reactive power.This thesis aims at behavior analysis and performance improvement of permanent-magnet synchronous generator-based wind turbines during grid faults. A simple method is presented to overcome the over current problem of the grid-side converter...
A higher index theorem for foliated manifolds with boundary
, Article Bulletin des Sciences Mathematiques ; Volume 136, Issue 2 , 2012 , Pages 201-238 ; 00074497 (ISSN) ; Sharif University of Technology
2012
Abstract
Following Gorokhovsky and Lott and using an extension of the b-pseudodifferential calculus of Melrose, we give a formula for the Chern character of the Dirac index class of a longitudinal Dirac type operators on a foliated manifold with boundary. For this purpose we use the Bismut local index formula in the context of noncommutative geometry. This paper uses heavily the methods and technical results developed by E. Leichtnam and P. Piazza
On vanishing of low-degree higher Â-genera
, Article Differential Geometry and its Application ; Volume 43 , 2015 , Pages 56-59 ; 09262245 (ISSN) ; Sharif University of Technology
2015
Abstract
In this short note we apply methods introduced by B. Hanke and T. Schick to prove the vanishing of (low degree) higher Â-genera for spin manifolds admitting a positive scalar curvature metric. Our aim is to provide a short proof for this beautiful result
Cluster-based adaptive SVM: a latent subdomains discovery method for domain adaptation problems
, Article Computer Vision and Image Understanding ; Volume 162 , 2017 , Pages 116-134 ; 10773142 (ISSN) ; Jamzad, M ; Sharif University of Technology
2017
Abstract
Machine learning algorithms often suffer from good generalization in testing domains especially when the training (source) and test (target) domains do not have similar distributions. To address this problem, several domain adaptation techniques have been proposed to improve the performance of the learning algorithms when they face accuracy degradation caused by the domain shift problem. In this paper, we focus on the non-homogeneous distributed target domains and propose a new latent subdomain discovery model to divide the target domain into subdomains while adapting them. It is expected that applying adaptation on subdomains increase the rate of detection in comparing with the situation...
MiR-9-5p and miR-106a-5p dysregulated in CD4+ T-cells of multiple sclerosis patients and targeted essential factors of T helper17/regulatory T-cells differentiation
, Article Iranian Journal of Basic Medical Sciences ; Volume 21, Issue 3 , March , 2018 , Pages 277-283 ; 20083866 (ISSN) ; Hosseini, A ; Ghaedi, K ; Kiani Esfahani, A ; Tanhaei, S ; Shiralian Esfahani, H ; Rahnamaee, S. Y ; Mowla, S. J ; Nasr Esfahani, M. H ; Sharif University of Technology
Mashhad University of Medical Sciences
2018
Abstract
Objective(s): Multiple sclerosis (MS) is considered as a chronic type of an inflammatory disease characterized by loss of myelin of CNS. Recent evidence indicates that Interleukin 17 (IL-17)-producing T helper cells (Th17 cells) population are increased and regulatory T cells (Treg cells) are decreased in MS. Despite extensive research in understanding the mechanism of Th17 and Treg differentiation, the role of microRNAs in MS is not completely understood. Thereby, as a step closer, we analyzed the expression profile of miR-9-5p and miR-106a-5p, and protein level of retinoic acid receptor (RAR)-related orphan receptor C (RORC; Th17 master transcription factor) as direct target of miR-106a-5p...
Indoor Noise Pollution Modeling: A Case Study on Resalat Tunnel
, M.Sc. Thesis Sharif University of Technology ; Vaziri, Manouchehr (Supervisor)
Abstract
Noise or noise pollution, is defined as an unwanted sound, produced mostly by motor vehicles in urban areas. If the noise exceeds its limit, adverse effects on users and citizens are expected. Thus the assessment of the noise level and its comparison with allowable values is mandatory. Traffic induced noise depends upon different factors such as traffic, weather, and, sound barriers. Noise pollution study has a long history all over the world. Many studies, mostly representing the outdoor noise pollution models, have been done in recent years. This paper presents an assessment of traffic-induced noise in a heavily traveled tunnel, locally referred to as Resalat tunnel, which is located in...
The Effect of Travel Time Reliability on Morning Peak Travellers route choice in Large Metropolitan Area
, M.Sc. Thesis Sharif University of Technology ; Poorzahedy, Hossein (Supervisor)
Abstract
Data collected from street networks show that travel time in urban street networks is a stochastic variable, whose range of variation increases with the congestion level. Work and school trips comprise the major part of morning peak volumes, whose common characteristic is that they need to be made on time. For this reason, these travelers are pessimistic in their route choice, and try to choose routes which are more reliable. Travel time standard deviation is one of the common measures for estimating travel time reliability that is related to properties of day-to-day travel time distribution on a particular route. Based on the empirical data collected from Tehran street network, this paper...
Design and Implementation of a FlexRay Transceiver
, M.Sc. Thesis Sharif University of Technology ; Atarodi, Mojtaba (Supervisor)
Abstract
With the advancement of automotive industry, the number of electronic systems that need to communicate with each other has increased. An effective strategy to meet these growing demands is using bus-based protocols, which can establish safe communication among numerous nodes with reasonable cost, weight, and space requirements. The objective of this thesis is the design and implementation of a transceiver based on the FlexRay protocol. The significance of this protocol lies in its ability to provide higher data transmission rates compared to other protocols like CAN and LIN, and its role as the foundational communication medium among various domains in modern vehicle architectures. In this...
Using Information Beyond Text to Generate Language Embedding Vectors
, M.Sc. Thesis Sharif University of Technology ; Sameti, Hossein (Supervisor)
Abstract
In this thesis, we introduce a novel Artificial Intelligence (AI) system inspired by the philosophical and psychoanalytical concept of imagination as a ``Re-construction of Experiences". Our AI system is equipped with an imagination-inspired module that bridges the gap between textual inputs and other modalities, enriching the derived information based on previously learned experiences. A unique feature of our system is its ability to formulate independent perceptions of inputs. This leads to unique interpretations of a concept that may differ from human interpretations but are equally valid, a phenomenon we term as ``Interpretable Misunderstanding". We employ large-scale models,...
Entanglement Distillation for Weakly Entangled States
, M.Sc. Thesis Sharif University of Technology ; Mirkamali, Maryam Sadat (Supervisor)
Abstract
Quantum entanglement is an essential resource in quantum information processing, such as quantum communication and quantum computing. Although entanglement is critical for practical implementations in these fields, creating and transmitting entanglement without altering the states is challenging. External noise may destroy or weaken the entanglement. Consequently, there is a need for methods to improve entanglement. Entanglement distillation is an effort to address this issue. It is a process where, probabilistically, a smaller number of strongly entangled states are created from a fixed number of noisy entangled states. This process is carried out using only local operations and classical...
Robust Design Optimization for Fatigue Life with Geometric and Material Uncertainties of Mechanical Parts Under Random Loading Based on Maximizing Fatigue Life and Minimizing Uncertainty in Fatigue Llife Prediction
, M.Sc. Thesis Sharif University of Technology ; Khodaygan, Saeed (Supervisor)
Abstract
Fatigue life prediction of a mechanical part is one of issues which a group of engineers are engaged with it and always they try to design the parts with the maximum of lifetime. Although many researches have been done in this field but yet we can see that predicted life are different from that happens in the reality because there are some uncertainties in the phenomena. Our effort in this project is creating an algorithm design so that the parts are designed by it, have the maximum fatigue life and the minimum uncertainty in prediction. In this project we have considered geometrical, material and random loading uncertainties as error resources. Older methods those are presented in this...
Deformation and Annealing Behavior of an Austenitic Stainless Steel
, M.Sc. Thesis Sharif University of Technology ; Serajzadeh, Siamak (Supervisor)
Abstract
In this research, non-isothermal annealing process at temperatures ranging between 400°C to 830 °C was investigated in warm and cold-rolled austenitic stainless steel 304L. First, the wide variety of austenitic to martensitic structure was produced by the multi-pass rolling process at room temperature -8 °C, 200 °C, and 280°C. The n exponent in Olson-Cohen equation was governed 2.83 after non-linear curve fitting to assess the fraction of deformation-induced martensite as a function of strain. Afterward, Abaqus/Explicit method was utilized to achieve the stored energy and plastic strains distribution through the thickness. Then, Cellular automata and Galerkin-finite element models were...
Efficient recyclable catalytic system for deoxygenation of sulfoxides: Catalysis of ionic liquid-molybdenum complexes in ionic liquid solution
, Article New Journal of Chemistry ; Volume 36, Issue 4 , Dec , 2012 , Pages 971-976 ; 11440546 (ISSN) ; Ghazali Esfahani, S ; Sharif University of Technology
2012
Abstract
Three newly synthesized room temperature ionic liquids containing molybdate anion, [DMIm][MoO 2(NCS) 4], [RPy][MoO 2(NCS) 4] (R = butyl or decyl), and previously reported [BMIm][MoO 2(NCS) 4] were used as catalysts for the reduction of sulfoxides. For facilitating the recyclability of the catalysts, the ionic liquids [RMIm][PF 6] and [RPy][PF 6] (RMIm = 1-n-alkyl-3-methylimidazolium, RPy = 1-n-alkylpyridinium) were applied as ionic solvents and toluene is used as solvent for the organic phase. Molybdenum salts immobilized in RTILs constituted a reusable and efficient heterogeneous catalyst system. A maximum conversion (>99%) was achieved for reduction of diphenyl sulfoxide to diphenyl...
Molybdenum liquid salts immobilized on ionic liquid-modified silica as efficient heterogeneous catalysts for sulfoxide reduction
, Article Tetrahedron Letters ; Volume 54, Issue 29 , 2013 , Pages 3765-3768 ; 00404039 (ISSN) ; Ghazali Esfahani, S ; Sharif University of Technology
2013
Abstract
Two room temperature liquid salts containing molybdenum(VI), [BMIM] 2[MoO2(NCS)4] (1) and [DMIM] 2[MoO2(NCS)4] (2), were immobilized on ionic liquid-modified silica leading to materials which showed notable catalytic activity for the reduction of sulfoxides into sulfides with triphenylphosphine (PPh3). The molybdenum liquid salts immobilized on the supported ionic liquid phase could be reused at least for three catalytic cycles without significant loss of activity
Epoxidation of olefins catalyzed by some cis-dioxomolybdenum(VI)-tridentate schiff base complexes with tert-butyl hydroperoxide
, Article Scientia Iranica ; Volume 17, Issue 2 C , 2010 , Pages 131-138 ; 10263098 (ISSN) ; Ghazali Esfahani, S ; Sharif University of Technology
2010
Abstract
Some cis-dioxomolybdenum (VI) complexes with tridentate Schiff base ligands derived from salicylaldehyde and aminophenols, aminoalcohol or o-aminobenzenethiol were examined as catalysts for epoxidation of different aliphatic and aromatic olefins, with tert-butyl hydroperoxide as oxidant. All complexes exhibited high activity and selectivity for epoxidation of aliphatic substrates during a short time period (95% conversion of cyclooctene after 30 min). The epoxide yield increased with the nucleophilic character of olefin. The catalysts activation strongly depends on the reaction temperature and nature of the solvent. Epoxidation of olefins by these catalysts is inhibited by ligands or...
Utilizing network coding for file dessimination in peer-to-peer systems
, Article 3rd International Conference on New Technologies, Mobility and Security, NTMS 2009, 20 December 2009 through 23 December 2009, Cairo ; 2009 ; 9781424462735 (ISBN) ; Movaghar, A ; Sadat Bathaee, N ; Sharif University of Technology
2009
Abstract
Network coding was first introduced in information theory for increasing the multicast rate in the networks with directed links. We can model many of the content distribution networks and overlay networks with such a network. Therefore, the solutions introduced in information theory can be used in these networks. In this paper, we analyze using of network coding in uncoordinated cooperative content distribution systems. Reaching the optimum performance in an uncoordinated system needs blocks of the system to be "equally important". In that case, we can retrieve the whole data without need of central controller or complex algorithms. In part of this paper, we exactly define the concept of...
Controlling longitudinal safe distance between vehicles
, Article Promet - Traffic - Traffico ; Volume 21, Issue 5 , 2009 , Pages 303-310 ; 03535320 (ISSN) ; Fathi, M ; Vaziri, M ; Sharif University of Technology
2009
Abstract
Controlling the safe distances between vehicles on freeways can be used to prevent many accidents. In this research, image-processing techniques have been used to develop an online system that calculates the longitudinal distances between vehicles. This system facilitates controlling safe distances between vehicles without the need for high technology devices. Our approach is real-time and simple, but efficient operations have been used to reduce the image occlusion problem. The main concept of this system is using simple, quick, and effective algorithms for calculating the position of each vehicle in each image. In this way, traffic parameters like speed and distances between vehicles can...
A novel structure of dithered nested digital delta sigma modulator with low-complexity low-spur for fractional frequency synthesizers
, Article COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering ; Volume 35, Issue 1 , 2016 , Pages 157-171 ; 03321649 (ISSN) ; Farshidi, E ; Sadoughi, S ; Sharif University of Technology
Emerald Group Publishing Ltd
2016
Abstract
Purpose - Digital Delta Sigma Modulator (DDSM) is used widely in electronic circuits including Radars, class-D power amplifiers and fractional frequency synthesizers. The purpose of this paper is to propose an implementation for MASH DDSMs named as Multi Modulus Reduced Complexity (MMRC) architecture. Design/methodology/approach - This architecture will use a very simple pseudorandom Linear Feedback Shift Register (LFSR) dither signal with period N-d to randomize the digital MMRC modulator used for fractional frequency synthesizers. Using error masking methodology, the MMRC modulator can decrease the hardware consumption and increase accuracy of the fractional frequency synthesizer. Rules...
Entropy-based video steganalysis of motion vectors
, Article Entropy ; Volume 20, Issue 4 , 2018 ; 10994300 (ISSN) ; Faez, K ; Saffari Pour, M ; Sharif University of Technology
MDPI AG
2018
Abstract
In this paper, a new method is proposed for motion vector steganalysis using the entropy value and its combination with the features of the optimized motion vector. In this method, the entropy of blocks is calculated to determine their texture and the precision of their motion vectors. Then, by using a fuzzy cluster, the blocks are clustered into the blocks with high and low texture, while the membership function of each block to a high texture class indicates the texture of that block. These membership functions are used to weight the effective features that are extracted by reconstructing the motion estimation equations. Characteristics of the results indicate that the use of entropy and...