Transportation Study in Tourist Villages, A Case Study of Niasar

, M.Sc. Thesis Sharif University of Technology Majdi, Omid (Author) ; Vaziri, Manouchehr (Supervisor)

Abstract

This study aimed to shed some light on travel behavior in tourist villages in Iran. Rural areas need efficacious transportation infrastructures and services to promote sustainable development and to avoid urban migration. By exploring the behavioural aspects of rural transportation, their transportation needs and demands can be effectively determined. Subsequently, accessibility and mobility of rural residents can be provided in a sustainable manner. In recent years, tourism has transformed lifestyle and behavior of some rural inhabitants. Utilizing secondary school students in Niasar, a simpliﬁed questionnaire was used to collect person and household data. Socio-economic, activity and trip...

Quantification of Seismic Performance Factors in Concentrically Braced Frames (CBFs) Equipped with Off-Center Bracing System (OBS)

, M.Sc. Thesis Sharif University of Technology Majdi, Reyhane (Author) ; Mofid, Masoud (Supervisor)

Abstract

Off-Center Bracing System is a kind of concentric bracing frame that consists of three members and with y- shape layout can provide a necessary opening in the building . Buildings have a concentric lateral bracing system equipped with Off-Center bracing system in lower floors are considered SCBF. to design these buildings according to regulations , it is needed to have Seismic performance coefficients such as response modification factor (R) , over strength factor (Ω0 ) and deflection amplification factor (Cd) .The purpose of the present investigation is quantifying these parameters and evaluation of accuracy based on the proposed method in FEMA P695.In the mentioned ...

Laplacian mixture model point based registration

, Article 9th Iranian Conference on Machine Vision and Image Processing, 18 November 2015 through 19 November 2015 ; Volume 2016-February , 2015 , Pages 57-60 ; 21666776 (ISSN) ; 9781467385398 (ISBN) Majdi, M. S ; Fatemizadeh, E ; Sharif University of Technology

IEEE Computer Society 2015

Abstract

Point base registration is an important part in many machine vision applications, medical diagnostics, agricultural studies etc. The goal of point set registration is to find correspondences between different data sets and estimate the appropriate transformation that can map one set to another. Here we introduce a novel method for matching of different data sets based on Laplacian distribution. We consider the alignment of two point sets as probability density estimation problem. By using maximum likelihood methods we try to fit the Laplacian mixture model (LMM) centroids (source point set) to the data point set

Developing Robust Image Similarity Measure in Feature Based Image Registration

, M.Sc. Thesis Sharif University of Technology Majdi, Mohammad Sadegh (Author) ; Fatemizadeh, Emad (Supervisor)

Abstract

Image registration is an important preprocessing step in analysis of medical images. Detection, Treatment plan, disease grows process analysis and assistance in surgical applications are some of medical images applications. We need to be able to compare different modalities in medical images such as X-ray, PET, MRI, and CT... , or sometimes doctors need to take images of a patient in a same modality but in different times and directions. In which in order to be able to do theses comparisons we need to first align these images by using image registration methods. Image registration is an image processing method in which tries to find a geometrical transformation that would map different...

Strong Revenue (Non-)Monotonicity of Single-parameter Auctions

, Article EC 2023 - Proceedings of the 24th ACM Conference on Economics and Computation ; 2023 , Pages 452-471 ; 979-840070104-7 (ISBN) Chen, Z ; Huang, Z ; Majdi, D ; Yan, Z ; Sharif University of Technology

Association for Computing Machinery, Inc 2023

Abstract

Consider Myerson's optimal auction with respect to an inaccurate prior, e.g., estimated from data, which is an underestimation of the true value distribution. Can the auctioneer expect getting at least the optimal revenue w.r.t. the inaccurate prior since the true value distribution is larger? This so-called strong revenue monotonicity is known to be true for single-parameter auctions when the feasible allocations form a matroid. We find that strong revenue monotonicity fails to generalize beyond the matroid setting, and further show that auctions in the matroid setting are the only downward-closed auctions that satisfy strong revenue monotonicity. On the flip side, we recover an approximate...

Effects of Graphene Nanopores and Temperature on DNA Sequencing Using Molecular Dynamics

, M.Sc. Thesis Sharif University of Technology Majdi, Amin (Author) ; Meghdari, Ali (Supervisor) ; Khoshnood, Atefeh (Co-Advisor)

Abstract

Distinguishing the structure of DNA is of outmost importance in the medicine and agriculture industry nowadays. Various methods have been suggested so far; however, high costs, incorrect results, and time-taking process are among main defects of them. Scientists try to find new ways for recognizing DNA structure and system in order to overcome such problems. One of these new methods is absorbing and passing DNA through Nano-pores in an electrolyte solution under the influence of an electrical field. The basis of this method is the ionized currents which occur due to the passing of DNA through Nano-pores. Because each DNA base pairs can form a barrier corresponding to a unique measured value,...

Non-linear assessment of tunable vibrating ring micro-gyroscopes design

, Article Mechanics Based Design of Structures and Machines ; 2023 ; 15397734 (ISSN) Sayyaadi, H ; Mokhtari Amir Majdi, M. A ; Askari, A. R ; Sharif University of Technology

Taylor and Francis Ltd 2023

Abstract

This paper introduces a tunable design for an electrically actuated vibrating ring micro-gyroscope. This mechanism contains eight piezoelectric micro-beams attached to the vibrating ring in each drive and sense directions. Employing a full geometric non-linear model for the vibrating ring and accounting for the micro-beam’s mid-plane stretching; the mathematical model associated with the present system is obtained. Afterward, utilizing the Hamilton principle together with the Ritz method, the reduced equations of motion are derived. The present results are validated by those available in the literature for simpler systems. A three-dimensional (3D) finite element (FE) simulation was carried...

Synthesize of Graphene Nanoribbons with a Non-Zero Energy Band Gap for Inactivation of Alive Cells Using Infrared Irradiation

, M.Sc. Thesis Sharif University of Technology Emamy, Hamed (Author) ; Akhavan, Omid (Supervisor)

Abstract

Graphene is a one layer atom thickness and zero energy gap so for using it in nano electronic and transistors baised on graphene it's energy gap should be opened.one of the methods for opening graphene band gap is creating nano scale boundaries or synthesize graphene nanoribbons. One of the new methods for graphene nanoribbon synthesize is longitudinal opening of carbon nanotube. In this thesis graphene nanoribbons synthesize with this method and analyze with AFM and Raman spectroscopy. Carbon nanotubes also have energy gap and IR absorption recently they used for living cell destruction. In this thesis we synthesize graphene nanoribbons and analyzing their optical absorption and use it for...

Fabrication of Graphene/TiO2 Nanowalls as Visible Lights Photocatalysts

, M.Sc. Thesis Sharif University of Technology Rahimi, Kourosh (Author) ; Akhavan, Omid (Supervisor)

Abstract

TiO2 is known as a photocatalyst in near UV-Visible light region with better efficiency compared to other semiconductor photocatalysts. Many attempts have been done to increase the efficiency of this photocatalyst. also, application of 2D carbon nanostructures namely graphene for increasing the photocatalytic activity of TiO2 has shown positive results.
In this research, we first synthesized Graphene Oxide (GO) suspension by exfolation of graphite oxide suspension. then we fabricated TiO2 thin films on glass substrates by so-called sol-gel method. finally we fabricate Graphene Oxide/TiO2 nanowalls composite films as a photocatalyst in visible light. X-ray photoelectron spectroscopy...

Fabrication of Graphene-WO3 Nanocomposites as Photocatalyst in the Visible Light Region

, M.Sc. Thesis Sharif University of Technology Choobtashani, Mohammad (Author) ; Akhavan, Omid (Supervisor)

Abstract

WO3 is known as a photocatalyst in the visible light region, but with lower efficiency compared to more interesting semiconductor photocatalysts such as TiO2 and ZnO. Many attempts have been done to increase the efficiency of this photocatalyst by incorporating metal and metal oxide nanoparticles or recently carbon nanotubes.On the other hand, application of graphene, as an unrolled carbon nanotube, for increasing the photocatalytic activity of TiO2 and ZnO has shown positive results. Furthermore, it was reported that such semiconductor photocatalysts (and very recently WO3) can photocatalytically reduce the chemically exfoliated graphene oxide sheets under UV-vis irradiation.
In this...

Synthesis of Graphene Nanosheets for Stem Cells Applications

, M.Sc. Thesis Sharif University of Technology Shahsavar, Mahla (Author) ; Akhavan, Omid (Supervisor)

Abstract

Graphene nanogrids fabricated by graphene nanoribbons obtained through oxidative unzipping of multi-walled carbon nanotubes, used as two-dimensional selective templates for accelerated differentiation of human mesenchymal stem cells (hMSCs), isolated from umbilical cord blood, into osteogenic lineage. The biocompatible and hydrophilic graphene nanogrids showed high actin cytoskeleton proliferations that coinciding with patterns of the nanogrids. The amounts of proliferations found are slightly better than proliferation on hydrophilic graphene oxide (GO) sheets, and significantly higher than non-uniform proliferations on hydrophobic reduced graphene oxide (rGO) sheets and polydimethylsiloxane...

Identifying the risks of Iranian Knowledge BasedFirms Using Fault Tree Analysis (FTA)

, M.Sc. Thesis Sharif University of Technology Sarhadi, Maryam (Author) ; Fattahi, Omid (Supervisor)

Abstract

Knowledge Based Firms are considered to be important for the economic development of a country in regards to both employment growth and innovative activity. The latter is believed to contribute significantly to the increase in productivity and therefore the competitiveness of Iran’s economy. This study contributes to the above literature by investigating the factors that are believed to treat the growth of such firms in Iran. The purpose of this study is to identify functional risks of vital signs monitors via Fault Tree Analysis (FTA) method to use as a guide for manufacturers to identify and control hazards. Therefore, 30 knowledge based firms were selected as sample. Then, based on a...

Synthesis of Graphene from Waste by Chemical Exfoliation and Study of It’s Physical Characteristics

, M.Sc. Thesis Sharif University of Technology Mirsepah, Ali (Author) ; Akhavan, Omid (Supervisor)

Abstract

One atom thick layer of pure carbon in bonded and hexagonal lattice is named graphene. graphene has unique mechanical, optical, thermal and electrical properties and because of these properties has grabbed attention. graphene has been made from high pure graphite by different methods such as CVD(chemical vapor deposition) , chemical exfoliation , micromechanical cleavage and colloidal suspension. through these methods, green methods for synthesis of graphene, using eco-friendly reductants during synthesis of graphene instead of hydrazine and recently using waste(not graphite) are attractive for synthesis of graphene. Following this idea , a group has produced graphene from wastes such as...

The Use of Hydrogen Rich Water for Synthesis of Hydrogenized Graphene and Investigation of Its Properties

, M.Sc. Thesis Sharif University of Technology Ghorbani, Fatemeh (Author) ; Akhavan, Omid (Supervisor)

Abstract

Graphene is a two dimensional lattice which is created from carbon atoms. Having special feature, it has such various medical usage, for example in diagnosing and treating cancer. Adding a particular factor to graphene could improve their efficiency. In comparis on with graphene itself, graphene oxide and reduced graphene oxide are much more successful in diagnosing and treating than others because of their higher hygroscopic. Recent studies state that hydrogenized combinations including hydrogenized graphene show desired results. Due to its higher hygroscopic and the possibility of adherence to the cells, hydrogenized graphene could be very effective in diagnosing and treating the sarcomas....

A Meta Heuristic Approach for Design of a Network System in Mass Customization

, M.Sc. Thesis Sharif University of Technology Puresmaili, Ehsan (Author) ; Fattahi, Omid (Supervisor)

Abstract

This study discusses about mass customization and optimization of supply network in which both goal considering to set the flow of raw material and final product to satisfy the customer demand. The mass customization is more important concept in this study, so that this goal is placed to the first objective. In this research, the model which contained both goal is presented. The model focus on mass customization and try to satisfy various products demand, which constitute 3 kind of speed demands. Each product can satisfy in 3 way: fast, normal, slow.In the first model the new approach present in which the speed affects all of supplying, manufacturing and distributing system. The system try...

Synthesis of Graphene Oxide and Study of its Fluorescence Properties

, M.Sc. Thesis Sharif University of Technology Akbari, Ebrahim (Author) ; Akhavan, Omid (Supervisor)

Abstract

Graphene oxide is a single sheet of Carbon atoms which has been arranged on a two-dimensional honeycomb lattice. Functional groups such as epoxy, carboxyl and carbonyl are located on basal plane and at the edges of graphene oxide and they localize electrons on the surface of graphene oxide and open band gap in its band structure. Pure graphene has zero band gap, so existence of fluorescence properties is unlikely; but graphene oxide has fluorescence properties due to band gap in its band structure. Fluorescence properties of graphene have been used in live cell imaging and drug delivery, so study and increasing of fluorescence properties is significantly important. The purpose of this...

A Novel Reliability Model for Information Technology Web services

, M.Sc. Thesis Sharif University of Technology (Author) ; Fatahi Valilai, Omid (Supervisor)

Abstract

The Internet is often used for communication-based applications such as online banking, stock trading, and shopping where service interruption is unacceptable. Thus, analysis of the impact of the failures of hardware, software, and related services’ performance quality of the service provided to users is of importance to designers and managers in these functions. In this study, we developed a strategy to the design of a dynamic combination of file servers with the aim of providing reliability and SLA. At first, we examine the reasons for the violation of service level in file host services and datacenters, and then we introduce the criteria to measure the violation of service level on the...

Development of a novel solution to enable integration and interoperability for cloud manufacturing

, Article 6th International Conference on Changeable, September 2016 through 6 September 2016 ; Volume 52 , 2016 , Pages 6-11 ; 22128271 (ISSN) Delaram, J ; Fatahi Valilai, Omid ; Sharif University of Technology

Elsevier B. V 2016

Abstract

Nowadays, manufacturing enterprises have been faced with a globalized competitive environment. In this fierce condition, Cloud Manufacturing paradigm emerged as a promising concept for competition. It provides effective solutions and tools for manufacturing enterprises to collaborate in globalized market. The revolution that Cloud Manufacturing has created is based on the redefinition of the classic methods to those which are appropriate for todays' modern and globalized manufacturing environments. In parallel with cloud-based revolution, the expansion of internet-based technologies has been started. These technologies previously have been applied in many fields and resulted in...

Product Portfolio Management Using Life Cycle Considerations

, M.Sc. Thesis Sharif University of Technology Ebrahimian, Mahsa (Author) ; Fattahi, Omid (Supervisor)

Abstract

Today’s organizations always encounter limitations on the way of achieving their goals. Budget constraint, inventory constraints, capital constraints are issues which complicates management decision making.
Global market has enabled manufacturers compete globally. Even position their factories in other countries and use of competitive advantages and other markets demand. This is why decision making in production and manufacturing domain has been complicated. Decision making in production and manufacturing should become faster and more precise in order to keep market competitiveness. Organization should make long term or strategic decisions and short term decisions about keeping the...

Fabricating Graphene Paper and Determining Its Electrical and Mechanical Properties and Using It for Proliferation and Differentiation of Neural Stem Cells

, M.Sc. Thesis Sharif University of Technology Akbar Shirazian, Soheil (Author) ; Akhavan, Omid (Supervisor)

Abstract

Nowadays, tissue engineering and stem cells-based therapies have outlined a promising prospect in neural networks regeneration. But it usually requires biocompatible and conductive scaffolds for culturing neural stem cells and directing their differentiation toward the neurons. Graphene due to its unique physical and chemical properties has attracted much interest in tissue engineering. For this purpose, in this study biocompatible graphene oxide foams have been used for neural stem cell culturing. For the first time, graphene oxide foam were fabricated by precipitation of chemically exfoliated graphene oxide sheets in an aqueous suspension onto the PET substrate at ~80 oC under UV...