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Development of Motor Imagery Based Real-Time BCI for Lower-Limb Exoskeleton

, M.Sc. Thesis Sharif University of Technology Koureshi Hazrat, Arya (Author) ; Ghazizdeh Ehsaei, Ali (Supervisor) ; Shamsollahi, Mohammad Bagher (Co-Supervisor)

Abstract

Severe motor impairments resulting from neurological injuries challenge the quality of life for millions. Brain-Computer Interface (BCI) technology offers a novel solution by creating a direct communication channel between the brain and external devices, thereby bypassing damaged neuro-muscular pathways. This research focuses on the development of a Brain-Computer Interface (BCI) system based on Motor Imagery (MI), utilizing non-invasive Electroencephalogram (EEG) signals. Aimed at controlling lower-limb exoskeleton robots, this system decodes the user's motor intention and rapidly translates it into physical movement. This capability, by facilitating sensory feedback and stimulating...

Eye Tracking using EEG Signals During Simultaneous Functional Magnetic Resonance Imaging

, M.Sc. Thesis Sharif University of Technology Mortazavi, Abolfazl (Author) ; Ghazizadeh Ehsaei Ehsaei, Ali (Supervisor) ; Shamsollahi, Mohammad Bagher (Supervisor)

Abstract

In certain behavioral neuroscience studies, precise monitoring of the subject's gaze direction and duration is of particular importance. However, the use of conventional eye-tracking systems in functional Magnetic Resonance Imaging (fMRI) environments faces significant challenges due to strong magnetic fields, physical constraints, and high costs. Aiming to provide a cost-effective alternative method, this study investigates the feasibility of utilizing Electroencephalogram (EEG) signals recorded simultaneously with fMRI to track eye direction and movement. To achieve this objective, several visual tasks were designed, including five-class, three-class, and passive viewing tasks. EEG and...

Evaluating Attention on Human Decision Making

, M.Sc. Thesis Sharif University of Technology Hazrati, Motahare (Author) ; Ghazizadeh Ehsaei, Ali (Supervisor)

Abstract

Exploring how economic rationality principles are compromised in choices involving three or more options is essential for understanding the cognitive and neural processes behind decision-making. Studies have found that as the value of a third (distractor) option increases, the relative accuracy of selecting between two primary options declines. This decline is believed to result from divisive normalization within neural value processing. However, recent research has challenged this finding, suggesting that the presence of a distractor may not impact choice accuracy. In our experiments, we modified and manipulated the choice task to evaluate attention more specifically. Contrary to...

Enhanced Neural Source Localization by Exploiting the Relation between EEG and fMRI

, M.Sc. Thesis Sharif University of Technology Ataie, Ali (Author) ; Amini, Arash (Supervisor) ; Ghazizadeh Ehsaei, Ali (Supervisor)

Abstract

Electroencephalography (EEG) and the functional magnetic resonance imaging (fMRI) are the two important non-invasive tools in probing the neural activity of human brain. EEG has a high temporal resolution while suffering a low spatial one. On the other hand, fMRI has a superior spatial resolution while offering a low temporal one. Enhancement of the spatial resolution of EEG source localization methods is of high importance due to multiple reasons such as its lower capital and operational costs compared with fMRI, its mobility and ease of use and extra. But all the EEG source localization methods have been the subject to a major problem, and it is absence of a ground-truth about the real...

Vocal Perception in Zebra Finches: Analysis of Measured Neural Responses to a Variety of Auditory Stimuli Using Neural Probe

, M.Sc. Thesis Sharif University of Technology Bahramani, Amir Reza (Author) ; Fardmanesh, Mehdi (Supervisor) ; Ghazizadeh Ehsaei, Ali (Supervisor)

Abstract

Vocal communication plays a vital role in the social interactions of many species, including humans. Songbirds, due to their complex abilities in learning and producing vocalizations, are considered a suitable animal model for studying the neural basis of these behaviors. This thesis, as the first comprehensive research in Iran in the field of neuroethology of songbirds, addresses this subject. Initially, considering the novelty of this field branch in the country, a comprehensive literature review was conducted on the fundamentals of neuroscience, the brain structure of birds, song learning, and vocal communication, with a focus on the zebra finch as an animal model. Subsequently, the...

Design and Implementation of the Power Supply of the Wireless Neural Recording System using the Electromagnetic Induction Method

, M.Sc. Thesis Sharif University of Technology Ahmadi Nabi, Sajad (Author) ; Ghazizadeh Ehsaei, Ali (Supervisor) ; Ahmadi, Mohammad Mahdi (Supervisor)

Abstract

This research focuses on the development and implementation of a wireless power transfer system based on magnetic induction to power wireless neural recording devices in experiments where animals move freely in a cage. The main goal of this research is to reduce the weight of the recording devices by eliminating the battery and using wireless power transfer. By removing the battery and employing magnetic induction, the final weight of the device is minimized, eliminating the need for battery replacement or recharging, and reducing the negative impact of the device's weight on the natural activities of the test animals. Power transfer for wireless neural recording devices is achieved through...

Technical English for mechanical engineers

, Book Alemi, Minoo ; Meghdari,Ali

Sharif University Press 2014

Abstract

Local educational institutions produce in-house English for Specific Purpose (ESP) materials according to the curriculum policies designated and developed by the Ministry of Higher Education In Iran. To this end, this book aims to be used in the Iranian setting at the tertiary level for undergraduate students majoring in Mechanical Engineering. Moreover, the style of English usage in this ESP textbook is American.
Regarding the content of the textbook, it has both thematic organizations in which the topics are relevant and includes sufficient treatment of the target language areas necessary for the students. The principle organizing approach of this textbook is theme-based. In addition,...

Feedback control of the neuro-musculoskeletal system in a forward dynamics simulation of stair locomotion [electronic resource]

, Article Proc. of IMechE Part H: Journal of Engineering in Medicine ; 2009, Vol. 223, No. 6, pp. 663-675 Journal of NeuroEngineering and Rehabilitation ; Volume 11, Issue 1, 30 April 2014, Article number 78 Selk Ghafari, A. (Ali) ; Meghdari, Ali ; Vossough, Gholam Reza ; Sharif University of Technology

Abstract

The aim of this study is to employ feedback control loops to provide a stable forward dynamics simulation of human movement under repeated position constraint conditions in the environment, particularly during stair climbing. A ten-degrees-of-freedom skeletal model containing 18 Hill-type musculotendon actuators per leg was employed to simulate the model in the sagittal plane. The postural tracking and obstacle avoidance were provided by the proportional—integral—derivative controller according to the modulation of the time rate change of the joint kinematics. The stability of the model was maintained by controlling the velocity of the body's centre of mass according to the desired centre of...

Design and Construction of a Soft Actuated Exoskeleton for Hand Rehabilitation of Stroke Patients

, M.Sc. Thesis Sharif University of Technology Razavi Zadehgan, Ali Akbar (Author) ; Ghafari, Ali (Supervisor) ; Meghdari, Ali (Supervisor)

Abstract

The main goal of this thesis is the design and development of a rehabilitation device for helping patients “to improve blood circulation” & retain and recover their abilities if possible that were lost during the stroke or a accident like that (my research in karaj/iran shows that it is possible by just movement of the specific body part). The focus is on hand in this thesis because Injuries to the hand are common and can be very debilitating since our hands are our primary means for interacting with our world. For rehabilitation in case of human hand there are several practices that should be done for patients either in home or in a rehabilitation center, time and money that is supposed to...

Silica chloride/wet SiO2 as a novel heterogeneous system for the deprotection of acetals under mild conditions [electronic resource]

, Article Phosphorus, Sulfur, and Silicon and the Related Elements ; Volume 178:2667-2670, Issue 12, 2003 Mirjalili, B. F. (BiBi Fatemeh) ; Pourjavadi, Ali ; Zolfigol, Mohammad Ali ; Bamoniri, Abdolhamid

Abstract

A combination of silica chloride and wet SiO2 was used as an effective deacetalizating agent for the conversion of acetals to their corresponding carbonyl derivatives under mild and heterogeneous condition

Earthquake Branch

, M.Sc. Thesis Sharif University of Technology Bagher Shemirani, Ali Reza (Author) ; Bakhshi, Ali (Supervisor)

Abstract

In the past few decades, shaking tables are widely used to evaluate system response of structures under seismic excitations. These devices are used without any fundamental research performed on a shaking table system as an entity model. In most of these studies for simplicity, it is assumed that there exist no considerable vibration and displacement around the shaking tables, and no attention is paid to the peripheral substances such as soil settled under the foundation.
In this thesis, result of ambient vibration test on shaking table system (solid deck, concrete foundation and soil layer) has been presented. Precise sensors known as low frequency and high accuracy accelerometers have...

Selective synthesis of conjugated enynes from α-arylalkynols using LiCl-Acidic Al2O3 under solvent-free conditions [electronic resource]

, Article Journal of Chemical Research ; Volume 2002, Number 8, 1 August 2002, pp. 378-380(3) Pourjavadi, A. (Ali) ; Bagheri Marandi, Gholam

Abstract

Free Content Selective synthesis of conjugated enynes from α-arylalkynols using LiCl-Acidic Al2O3 under solvent-free conditions

Selective preparation of fluorescent 1,8-naphthalimides using acidic alumina under microwave irradiation [electronic resource]

, Article Journal of Chemical Research ; 01/2001; 2001(11):485-487 Pourjavadi, A. (Ali) ; Bagheri Marandi, Gholam

Abstract

7H-benzimidazo[2,1-a]benz[de]isoquinolin-7-one compounds were prepared in a selective manner by reaction between o-phenylenediamines and appropriate 1,8-naphthalenedicarboxylic anhydrides using acidic alumina under microwave irradiation

Comparison between Performance of Stone Columns and RAPs from the Bearing Capacity and Settlement Reduction Viewpoints

, M.Sc. Thesis Sharif University of Technology Golestani Dariani, Ali Akbar (Author) ; Pak, Ali (Supervisor)

Abstract

Out of several ground improvement techniques available, stone columns have been widely used. This technique has been successfully applied to increase the bearing capacity and to reduce the settlement for foundation of structures like liquid storage tanks, earthen embankments, raft foundations, etc., where a relatively large settlement is permissible. This technique has, generally, been proven successful in increasing the stiffness of weak soils, upgrading their safe bearing capacity, and reducing their total and differential settlements, as well as speeding up their consolidation process. The beneficial effects of stone column installation in weak deposits is manifested in the form of...

Performance of Partially Filled Mini-Channels with Porous Media

, M.Sc. Thesis Sharif University of Technology Azimi, Adel (Author) ; Nouri, Ali (Supervisor) ; Moosavi, Ali (Co-Advisor)

Abstract

Laminar forced convection flow through a channel partially filled with a porous material was numerically studied in this thesis. The Navier-Stokes and Brinkman-Forchheimer equations were used to model the fluid flow in the free and porous regions, respectively. Coupling of the pressure and velocity fields was resolved using the SIMPLEC algorithm. The local thermal equilibrium was adopted in the energy equation. The effects of the thermal conductivity ratio, Darcy number, porosity, Reynolds number and height of the porous insert on velocity and temperature field were investigated. The results show that the flow behavior and its associated heat transfer are susceptible to the variation of the...

Improvement of Stability of Haptic Force Interaction with Virtual Environments Using a Haptic Interface with a Separate Tracker

, M.Sc. Thesis Sharif University of Technology Mashayekhi, Ahmad (Author) ; Meghdari, Ali (Supervisor) ; Nahvi, Ali (Supervisor)

Abstract

In the present study, a new version of haptic devices is presented in which user’s hand is in contact with the device just while collision with virtual surface. In this system, the position of user’s finger can be traced by using a camera and the haptic device follows user’s finger at the distance of about two centimeters. While the haptic device approaches to the virtual surface, gradually reduces its speed and stops about two centimeters distant of virtual plane. Then user’s hand collides with the haptic device which is static. Greater fidelity, transparency, more stability and also no need to large actuators are of the advantages of this system. In this project, first we present a new...

Simulation of the Biomolecule Imaging and Manipulation Via AFM by Molecular Dynamics Method

, M.Sc. Thesis Sharif University of Technology Kheiroddin, Mohsen (Author) ; Meghdari, Ali (Supervisor) ; Moosavi, Ali (Supervisor)

Abstract

In this thesis we try to find optimized parameters for imaging and manipulation of a biosample with AFM. For this we have prepared a numerous Molecular Dynamics simulation and find some reliable result. So, first we have focused on imaging process in Non contact mode (the less harmful mode). Then we headed into the manipulation process. The main problem about manipulating a biosample is the environment. In imaging section, the process of imaging a biomolecule by AFM is modeled using molecular dynamics simulations. Since the large normal force exerted by the tip on the biosample in contact and tapping modes may damage the sample structure and produce irreversible deformation, the non-contact...

Characterzing Variation of Small Strain Shear Modulus of Unsaturated Sand During Hydraulic Hysteresis with Bender Elements

, M.Sc. Thesis Sharif University of Technology Shahbazan, Parisa (Author) ; Pak, Ali (Supervisor) ; Khosravi, Ali (Supervisor)

Abstract

Results of previous studies on silt and clay indicated that variations in the small strain shear modulus, Gmax, during drying had a non-linear increasing trend with matric suction with greater values upon wetting. However, due to different material properties and inter-particle forces, different behaviour in Gmax is expected for sand. Although considerable research has been devoted in recent years to characterize the behaviour of Gmax of sand during drying, rather less attention has been paid to the effect of hydraulic hysteresis on Gmax and its variations during wetting. In the study presented herein, an effort was made to characterize the variation of Gmax for specimens of sand during...

Sequential Competitive Facility Location In Continuous Geometric Space

, M.Sc. Thesis Sharif University of Technology Lavasani, Ali Mohammad (Author) ; Abam, Mohammad Ali (Supervisor)

Abstract

Abstract The problem of competetive facility location can be defined as follows: There are a number of customers in the form of points in space, and two players arrange a number of facilities in the form of points in space, given some limitations, respectively. Each customer’s connection to each facility has a cost for the customer and an advantage for the facility, and each customer wants to be connected to at most one of the facilities which has the lowest cost for him. The goal is to find the strategy of placing the facilities and determining the cost which the facility receives from the customer, in such a way that the player’s profit is maximised.In this thesis, we first sought to...

Distributed Verifiable Computing: Algorithms and Analysis

, M.Sc. Thesis Sharif University of Technology Rahimi, Ali (Author) ; Maddah Ali, Mohammad Ali (Supervisor)

Abstract

Zero knowledge proofs allow a person (prover) to convince another person (verifier) that he has performed a specific computation on a secret data correctly, and has obtained a true answer, without having to disclose the secret data. QAP (Quadratic Arithmetic Program) based zkSNARKs (zero knowledge Succinct Non-interactive Argument of Knowledge) are a type of zero knowledge proof. They have several properties that make them attractive in practice, e.g. verifier's work is very easy. So they are used in many areas such as Blockchain and cloud computing. But yet prover's work in QAP based zkSNARKs is heavy, therefore, it may not be possible for a prover with limited processing resource to run...