Loading...
Search for: shafaei--mahsa
0.114 seconds

    Modeling Information Cascade in Social Network with Positive and Negative

    , M.Sc. Thesis Sharif University of Technology Shafaei, Mahsa (Author) ; Jalili, Mahdi (Supervisor)
    Abstract
    Information cascade or affection in a broad social network is introduced as a dynamic epidemic phenomenon in the society. As people notify a new innovation, technology, or hobby, they try to share it with their friends, colleges or neighbors. Till now most of the cascade models are presented for unsigned network, in which all links have the same sign (such as friends and trusted networks). In these networks cascade is independent of the edge sign. But in reality signed networks are as common as simple networks. Thus, in this thesis, we study information cascade in networks with positive and negative edges. We link the cascade size to community structure of signed networks; communities are... 

    Community structure and information cascade in signed networks

    , Article New Generation Computing ; Vol. 32, issue. 3-4 , August , 2014 , p. 257-269 Shafaei, M ; Jalili, M ; Sharif University of Technology
    2014
    Abstract
    In this paper, we study information cascade in networks with positive and negative edges. The cascade depth is correlated with community structure of signed networks where communities are defined such that positive inter-community and negative intra-community links are minimized. The cascade is initialized from a number of nodes that are selected randomly. Finally, the number of nodes that have participated in the cascade is interpreted as cascade depth; the more the number of such nodes, the more the depth of the cascade. We investigate influence of community structure (i.e.; percentage of inter-community positive and intra-community negative links) on the cascade depth. We find significant... 

    Evaluation of Lump Sum Contracts in the Organization for Development, Renovation and Equipping Schools

    , M.Sc. Thesis Sharif University of Technology Shafaei, Mohsen (Author) ; Mofid, Masoud (Supervisor)
    Abstract
    The construction industry is one of the most important economic sectors, which shares a major part of Gross Domestic Product (GDP) and employment. In Iran many development projects are designed and implemented annually which billions of Rials are due as a result of construction and operation for executive bodies. The Organization for Development, Renovation and Equipping Schools (ODRES) as the executive branch of the Ministry of Education, is one of the largest construction bodies which undertakes construction of hundreds of educational, cultural and athletic projects annually. Given that the project delivery methods and the need to choose the correct method of contract payments exerts great... 

    Crosstalk Fault Modeling and Mitigation in System-on-Chips

    , M.Sc. Thesis Sharif University of Technology Shafaei Moghaddam, Mansour (Author) ; Miremadi, Ghassem (Supervisor)
    Abstract
    Use of nano-scale VLSI technologies in the fabrication of System-on-Chips (SoCs) makes reliability as one of the major issues in the design and implementation of these products. SoCs are susceptible to several fault sources such as crosstalks, cosmic particle strikes, electromagnetic interferences, and power supply disturbances. Among the mentioned fault sources, crosstalks have the major contribution in threatening the reliability of SoCs. This thesis addresses the modeling and mitigation of crosstalk faults. In this regard, two analytical models and three crosstalk reduction methods have been introduced. The proposed analytical models, which have been introduced in the fourth chapter of... 

    , M.Sc. Thesis Sharif University of Technology Boraghi, Mahsa Sadat (Author) ; Parsafar, Gholamabbas (Supervisor)
    Abstract
    In 2009, a general equation of state (EOS-III) based on an effective near-neighbor pair interaction of an extended Lennard-Jones (3, 6, 12) type has been introduced as : , where is the compressibility factor, p and ρ stand for pressure and molar density , respectively, T is Temperature , and e, f and g are the temperature dependent coefficient of the equation of state . the Z_th and Z_in are the thermal and internal contributions of pressure in the compressibility factor, respectively. this equation of state gives a good description of all types of nano- and bulk –solid and bulk fluid at entire temperature and pressure ranges for which thee is experimental data. Investigation show that... 

    Numeral-based crosstalk avoidance coding to reliable NoC design

    , Article Proceedings - 2011 14th Euromicro Conference on Digital System Design: Architectures, Methods and Tools, DSD 2011 ; 2011 , Pages 55-62 ; 9780769544946 (ISBN) Shafaei, M ; Patooghy, A ; Miremadi, S. G ; Sharif University of Technology
    2011
    Abstract
    This paper proposes a Numeral-Based Crosstalk Avoidance Coding (NB-CAC) to protect communication channels of Network-on-Chips (NoCs) against crosstalk faults. The NB-CAC scheme produces codewords without bit patterns '101' and '010' to eliminate harmful transition patterns from NoC channels. This is done by the use of a new numeral system proposed in the paper. Using the proposed numeral system, the NB-CAC scheme 1) can be utilized in NoC channels with any arbitrary width, and 2) can be implemented with low area, power, and timing overheads. VHDL and SPICE simulations have been carried out for a wide range of channel widths to evaluate delay, area, and power consumption of the NB-CAC codecs.... 

    Crosstalk modeling to predict channel delay in Network-on-Chips

    , Article Proceedings - IEEE International Conference on Computer Design: VLSI in Computers and Processors, 3 October 2010 through 6 October 2010 ; October , 2010 , Pages 396-401 ; 10636404 (ISSN) ; 9781424489350 (ISBN) Patooghy, A ; Miremadi, S. G ; Shafaei, M ; Sharif University of Technology
    2010
    Abstract
    Communication channels in Network-on-Chips (NoCs) are highly susceptible to crosstalk faults due to the use of nano-scale VLSI technologies in the fabrication of NoCs. Crosstalk faults cause variable timing delay in NoC channels based on the patterns of transitions appearing on the channels. This paper proposes an analytical model to estimate the timing delay of an NoC channel in the presence of crosstalk faults. The model calculates expected number of 4C, 3C, 2C, and 1C transition patterns to predict delay of a K-bit communication channel. The model is applicable for both non-protected channels and channels which are protected by crosstalk mitigation methods. Spice simulations are done in a... 

    Optimization, Fabrication and Utilization of a New Tendon Actuated Manipulator with Lockable Joints

    , M.Sc. Thesis Sharif University of Technology Shafaei, Mohsen (Author) ; Alasty, Aria (Supervisor) ; Salarieh, Hassan (Supervisor)
    Abstract
    Serpentine manipulators are a kind of hybrid manipulators that have a large number of joints and degrees of freedom. Due to their high flexibility, they have a great potential to work in constrained environment that filled with obstacles. One of the main problems of this type of manipulators is high weight and controlling difficulties. Many researches have been done to achieve lighter weight and simplify control methods of hyper-redundant manipulator. One way is putting the actuators in the base of the manipulator and transferring the actuator forces by cable. In this way, one cable and one actuator per controllable DOF is needed. Therefore, the weight and cost will increase dramatically... 

    Photoelectrocatalytic Performance of Mesoporous TiO2 Nanostructures Decorated with Cu-Ag-Zn Particles for CO2 Conversion

    , M.Sc. Thesis Sharif University of Technology Adel Rastkhiz, Mahsa Sadat (Author) ; Simchi, Abdolreza (Supervisor)
    Abstract
    The rise in carbon dioxide levels has led to the manifestation of numerous environmental challenges. Currently, the absorption and conversion of carbon dioxide into valuable fuel resources such as synthetic gas, methane, and ethylene are deemed crucial from both environmental and economic standpoints. Despite the presentation of photocatalysts such as titanium oxide and electrocatalysts such as copper, silver, and zinc, their efficiency in CO2 conversion is found to be insufficient. One potential solution to this problem is the utilization of photoelectrocatalytic CO2 recovery. In this study, the aim was to enhance the photoelectrocatalytic reduction of CO2 by designing and manufacturing... 

    Aging Based Cache Policy for The Network of Caches

    , M.Sc. Thesis Sharif University of Technology Shafaei, Shayan (Author) ; Rezazad, Mostafa (Supervisor) ; Ghahramani, Amirali (Co-Supervisor)
    Abstract
    The basis of the current IP-based networking architecture is on addressing locations (IP addresses). This way of locating and searching content does not meet the existing applications’ demands for generating and consuming larger data. In order to confront this problem, Named Data Networking (NDN) has been proposed that allocates names to data instead of the location. This fundamental change improves the functionality of the network in terms of various aspects such as smoother mobile routing, higher security, intrinsic multicast, broadcast system, and enables caching at the network level. As data directly receives an address in NDN, it can reside anywhere in the network. Furthermore, content... 

    Coating of Sewage Pipes with Appropriate Nanomaterials Aimed at Preventing Biological Growth (Algae+Biofilm)

    , M.Sc. Thesis Sharif University of Technology Nezameddin, Mahsa Sadat (Author) ; Borghei, Mehdi (Supervisor) ; Ghasemi, Shahnaz (Co-Supervisor)
    Abstract
    Biological layers are one of the main problems related to water transfer with pipe lines which are formed through time in the inner surface of the pipes by the water nutrients. Hence, the inner surfaces in the pipe lines and water refineries should be made in order not to let these biological layers to be made. The reason is that when the biofilm is formed on these surfaces, the traversing water is polluted. Dredging of these pipes is not only necessary in most of the countries in the world and needs huge amounts of water but is also very complex and expensive.In this research, nanomaterials, namely ZnO, T〖iO〗_2،S〖iO〗_2 have been used to cover the surface of concrete and steel pipes (The... 

    Synthesis and Application of Preformed Viscoelastic Hydrogels in Enhanced Oil Recovery

    , M.Sc. Thesis Sharif University of Technology Aqcheli, Farzad (Author) ; Taghikhani, Vahid (Supervisor) ; Baghban Salehi, Mahsa (Supervisor)
    Abstract
    Preformed particle gels (PPGs) due to its advatantage over commonly used in situ gels has been successfully applied for controlling excess water production in mature oil reservoirs. Field results of using PPGs in oil fields shows that commonly used PPGs are highly sensitive to hard reservoir conditions such as high temperature and salinity and can not effectively block fractures and high permeability layers.Objects of this study are synthesis and evaluating performance of this novel polymer based hydrogel in oil reservoirs with high temperature and salinity. Central composite design ( which is a experiment design approach) was used for synthesizing thirteen gel samples and optimal sample was... 

    Design and Manufacture of Polymeric Nanocomposite in Order to Control the Production and Migration of Sand in Reservoirs

    , Ph.D. Dissertation Sharif University of Technology Saghandali, Farzin (Author) ; Taghikhani, Vahid (Supervisor) ; Baghban Salehi, Mahsa (Supervisor)
    Abstract
    Sand production from oil reservoirs leads to various problems, such as well productivity reduction, operating equipment corrosion, and increased production costs. Therefore, controlling sand production in unconsolidated reservoirs is crucial for operating companies. Chemical injection into the formation in order to strengthen and reduce sand production is one of the most important methods of sand control. In this study, a hydrogel nanocomposite was designed and its effectiveness in sand control was investigated. Various tests were carried out to define and assess its efficacy, as follows: Morphological tests demonstrated the creation of a dense, homogeneous, and porous structure. Structural... 

    Butanol Production from Bagasse Sugarcane Black Liquor by Native Strain and Clostridium Acetobutylicum Species

    , M.Sc. Thesis Sharif University of Technology Hassani Atashgah, Milad (Author) ; Shayegan, Jalaleddin (Supervisor) ; Vossoughi, Manouchehr (Supervisor) ; Sedighi, Mahsa (Co-Supervisor)
    Abstract
    Considering the limitations of fossil fuels in recent years, as well as increasing demand for biofuels, it is anticipated that future attention to biofuels will increase further. Among biofuels, due to some disadvantages of bioethanol and biodiesel fuel, there is a tendency to use biobutanol, which does not have the disadvantages of the mentioned fuels. The cost of chemical production of butanol also led researchers to use biotechnology production of butanol. According to studies, butanol production can be achieved by fermenting some sugars such as glucose, xylose, and ... by anaerobic microorganism, but the cost of using these sugars has resulted in the use of natural sources of these... 

    Performance Evaluation of Rhamnolipid & Sophorolipid Biosurfactants Capable of Wettability Change and Oil Recovery Increase

    , M.Sc. Thesis Sharif University of Technology Aghaei, Sadegh (Author) ; Taghikhani, Vahid (Supervisor) ; Baghban Salehi, Mahsa (Supervisor) ; Mokhtarani, Babak (Co-Supervisor)
    Abstract
    As fossil fuels are still the world's most important source of energy, as well as the maturity of most of the world's oil reservoirs, there is a need for enhanced oil recovery methods to meet the world's increasing oil demands. MEOR methods are new and promising methods that are still in the research and development stage. One of the MEOR methods is the use of biosurfactants, which increase the oil recovery by two mechanisms: 1) reducing the interfacial tension between water and oil and 2) changing the wettability of the rock. In this study, the performance of two glycolipid biosurfactants, rhamnolipid and sophorolipid, in increasing oil recovery has been investigated. Initially, surface... 

    Investigation of the Effect of Asphaltene on the Stability of Water-oil Emulsion

    , M.Sc. Thesis Sharif University of Technology Hosseini, Amir (Author) ; Taghikhani, Vahid (Supervisor) ; Baghban Salehi, Mahsa (Supervisor) ; Masihi, Mohsen (Supervisor)
    Abstract
    During the production of crude oil from reservoirs, the production of quantities of formation water along with this oil, causes the crude oil does not have the necessary indicators for transportation, refining and ultimately export. The presence of water and salt along with crude oil causes corrosion of refinery and transmission equipment and makes oil unfavorable in terms of economic efficiency (both for domestic use and for export). water and salt produce stable emulsion with oil that can be stable for a long time and can not be easily separated from crude oil. Therefore, separation of water and salt from crude oil is one of the most important issues in the oil industry. Breaking this... 

    Providing A New Solution to Enhance Oil Recovery (Eor) by Using Properties of Imidazolium Ionic Liquids and Synthesis of Microgels

    , M.Sc. Thesis Sharif University of Technology Harighi, Hooman (Author) ; Taghikhani, Vahid (Supervisor) ; Baghban Salehi, Mahsa (Supervisor) ; Mokhtarani, Babak (Co-Supervisor)
    Abstract
    The methods of Enhanced Oil Recovery (EOR) from reservoirs have been taken into consideration recently due to the decline in oil reserves and the rise in energy demand. Studies and investigations indicate the tremendous potential of chemical approaches based on injecting ionic liquids into the porous media with the goal of improving oil recovery. Additionally, hydrogels and polymers, which are two of the process' primary materials, are thought to be good alternatives. In the current study, a hydrogel based on carboxymethyl cellulose was first created and synthesized. Ionic liquids based on imidazolium and triflate anion were then added, and their effectiveness in enhancing the properties... 

    Evaluation of the Surface Activity of Novel Ionic Liquids and Their Application in the Enhanced Oil Recovery Process

    , M.Sc. Thesis Sharif University of Technology Hosseinzadeh Semnani, Radman (Author) ; Taghikhani, Vahid (Supervisor) ; Mokhtarani, Babak (Supervisor) ; Baghban Salehi, Mahsa (Co-Supervisor)
    Abstract
    The following dissertation discusses Ionic Liquids (ILs) as an alternative to commercial surfactants for use in the Enhanced Oil Recovery process. Ionic Liquids came to researchers’ attention due to their environmental nature and their tolerance for high temperatures and salinity. In this work, firstly, an extensive literature review is carried out, and then, experiments are designed and performed to evaluate ILs’ surface activity and performance in a lab-scale EOR set-up. The Ionic Liquids used in this work consist of three types of methylimidazolium nitrate, [MIM]+[NO3]-, with three different alkyl chain lengths. This combination, and specifically the effect of nitrate anions on EOR and... 

    PH-Sensitive stimulus-responsive nanocarriers for targeted delivery of therapeutic agents

    , Article Wiley Interdisciplinary Reviews: Nanomedicine and Nanobiotechnology ; Volume 8, Issue 5 , 2016 , Pages 696-716 ; 19395116 (ISSN) Karimi, M ; Eslami, M ; Sahandi Zangabad, P ; Mirab, F ; Farajisafiloo, N ; Shafaei, Z ; Ghosh, D ; Bozorgomid, M ; Dashkhaneh, F ; Hamblin, M. R ; Sharif University of Technology
    Wiley-Blackwell  2016
    Abstract
    In recent years miscellaneous smart micro/nanosystems that respond to various exogenous/endogenous stimuli including temperature, magnetic/electric field, mechanical force, ultrasound/light irradiation, redox potentials, and biomolecule concentration have been developed for targeted delivery and release of encapsulated therapeutic agents such as drugs, genes, proteins, and metal ions specifically at their required site of action. Owing to physiological differences between malignant and normal cells, or between tumors and normal tissues, pH-sensitive nanosystems represent promising smart delivery vehicles for transport and delivery of anticancer agents. Furthermore, pH-sensitive systems... 

    Smart micro/nanoparticles in stimulus-responsive drug/gene delivery systems

    , Article Chemical Society Reviews ; Volume 45, Issue 5 , 2016 , Pages 1457-1501 ; 03060012 (ISSN) Karimi, M ; Ghasemi, A ; Sahandi Zangabad, P ; Rahighi, R ; Moosavi Basri, S. M ; Mirshekari, H ; Amiri, M ; Shafaei Pishabad, Z ; Aslani, A ; Bozorgomid, M ; Ghosh, D ; Beyzavi, A ; Vaseghi, A ; Aref, A. R ; Haghani, L ; Bahrami, S ; Hamblin, M. R ; Sharif University of Technology
    Royal Society of Chemistry  2016
    Abstract
    New achievements in the realm of nanoscience and innovative techniques of nanomedicine have moved micro/nanoparticles (MNPs) to the point of becoming actually useful for practical applications in the near future. Various differences between the extracellular and intracellular environments of cancerous and normal cells and the particular characteristics of tumors such as physicochemical properties, neovasculature, elasticity, surface electrical charge, and pH have motivated the design and fabrication of inventive "smart" MNPs for stimulus-responsive controlled drug release. These novel MNPs can be tailored to be responsive to pH variations, redox potential, enzymatic activation, thermal...