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Improvement of Routing Approaches in Delay-Tolerant Mobile Networks

, M.Sc. Thesis Sharif University of Technology Yadegari, Manizhe (Author) ; Hemmatyar, Ali mohammad Afshin (Supervisor)

Abstract

Delay Tolerant Networks are types of mobile Ad-hoc networks, in where because of the high node mobility, low node density and node diversity, there is not full connection between nodes in the whole network; therefore, the probability of existence of end-to-end path between source and destination is low. Due to these properties, message routing in delay tolerant networks has turned to be a challenge, this type of networks work based on the concept of store, carry, forward; for instance, a node may store a message in the buffer for a long time and carry it along until meeting an appropriate contact opportunity. Delay tolerant networks are capable of providing communication services in...

Effect of Entrepreneurship Activities on the Well-Being of People; Considering Personal Values as a Mediator

, M.Sc. Thesis Sharif University of Technology Yadegari, Saeedeh (Author) ; Tasavori, Misagh (Supervisor)

Abstract

Entrepreneurial activities have always been considered and investigated due to the economic and social effects they have on societies. In research, in addition to the effects of entrepreneurship at the country level, attention has also been paid to its outputs for entrepreneurs. Since people choose this path according to their goals, values , and personal criteria, it is important and necessary to study people and examine the effects of this activity on them. Well-being is one of the concepts that has been considered in this regard. Well-being in general means experiencing positive emotions, avoiding negative ones, and evaluating life positively. Therefore, well-being is one of the things...

Mineral Rights Auction’s Valuation Paradigms: Case Study, The Gulf of Mexico

, M.Sc. Thesis Sharif University of Technology Yadegari, Ali (Author) ; Fatemi Ardestani, Farshad (Supervisor)

Abstract

Auction literature and economic theories advocate common valuation among bidders in mineral rights auctions. In this study, we have tried to examine the assumption of common valuation between bidders in a first price sealed bid auction. It examines the common valuation hypothesis by assuming the information symmetry and the exogenous entry of bidders. The findings of this study suggest that bidders’ valuation in a first price sealed bid auction of natural resources may be private or common value. We use the non-parametric estimation model to find that after the federal government imposed Area-wide Leasing in the Gulf of Mexico, bidders’ valuations changed from private valuation to common...

Effects of MR-fluid on low-velocity impact response of MR-laminated beams

, Article 2017 2nd International Conference on Smart Materials Technologies, ICSMT 2017, 19 May 2017 through 21 May 2017 ; Volume 1858 , 2017 ; 0094243X (ISSN); 9780735415324 (ISBN) Zabihollah, A ; Selk Ghafari, A ; Yadegari, A ; Rashidi, D ; Sharif University of Technology

American Institute of Physics Inc 2017

Abstract

Laminated composite structures are vulnerable to failure when subjected to impact and vibration. The present work investigates the impact response of laminated composite structures filled with MR-fluid segments. The mathematical modelling of a composite plate is presented using finite element method with MATLAB® software to study the vibration response due to impact loads. A proof-of-the-concept experimental work has been set up in order to illustrate the performance and functionality of the MR-fluid on damping vibration for MR-laminated composite structures. © 2017 Author(s)

Intelligent Fault Diagnosis using Multiple Sensor Data Fusion for Detecting Misalignment and Unbalance

, M.Sc. Thesis Sharif University of Technology Yadegari, Mohammad Erfan (Author) ; Behzad, Mehdi (Supervisor) ; Arghand, Hesam Al-Din (Co-Supervisor)

Abstract

Intelligent predictive maintenance is recognized as a cornerstone of Industry 4.0, where intelligent software is employed for the early detection of faults and the prevention of unexpected failures. Recent research indicates that the integration of multi-sensor data for fault diagnosis of gearboxes and bearings, using artificial intelligence models, has been successful. However, conventional methods face several challenges. These include an over-reliance on the signal characteristics of a single sensor and the impracticality of applying intelligent learning methods, particularly deep learning, despite their high potential, due to the unavailability of sufficiently large and diverse...

Investigating the Effect of Similarity and Complementarity of Companies’ Knowledge on the Formation of Strategic Alliance: a Case Study of the Biotechnology Industry

, M.Sc. Thesis Sharif University of Technology Ghassemian Yadegari, Kowsar (Author) ; Arasti, Mohammad Reza (Supervisor) ; Farazi, Mohammad Saleh (Supervisor)

Abstract

The aim of this research is to investigate the relationship between "knowledge relatedness" and “strategic alliance formation”. The tendency to cooperate has been increasing among companies in recent decades. Strategic alliances are considered one of the main types of cooperation. In a complex environment (especially in knowledge-based industries), there are few companies that prefer to rely only on their knowledge and technical capabilities to achieve innovation goals. It seems that the degree of relatedness of knowledge base between two firms influences their decision to enter into a strategic alliance. Knowledge relatedness is evaluated through the complementarity or similarity of the...

Bottom-up synthesis of nitrogen and oxygen co-decorated carbon quantum dots with enhanced DNA plasmid expression

, Article Colloids and Surfaces B: Biointerfaces ; Volume 184 , 2019 ; 09277765 (ISSN) Yadegari, A ; Khezri, J ; Esfandiari, S ; Mahdavi, H ; Karkhane, A. A ; Rahighi, R ; Heidarimoghadam, R ; Tayebi, L ; Hashemi, E ; Farmany, A ; Sharif University of Technology

Elsevier B.V 2019

Abstract

In this paper, a bottom-up hydrothermal route is reported for the synthesis of oxygen and nitrogen co-decorated carbon quantum dots (CQDs) using ammonium hydrogen citrate (AHC) as a single precursor. DLS data approved the formation of 4.0 nm (average size) CQDs. XRD pattern shows the interlayer spacing (002) of 3.5 Å for CQDs, which is exactly the same as that of crystalline graphite. XPS and FTIR spectra verified the formation of oxygen and nitrogen functional groups on the CQDs surface. Co-decorated carboxyl, hydroxyl and amine groups on the CQDs surfaces make them as promising polyelectrolyte for gene delivery. Toxicity assay showed a survival rate of 70% under different incubation times...

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...