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    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... 

    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... 

    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... 

    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... 

    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... 

    Percolation theory in reservoir engineering

    , Book King, P. R ; Masihi, Mohsen
    World Scientific  2018

    Vehicle Routing Problems with Mobile and Stochastic Customer Locations (VRP-MSCL)

    , Ph.D. Dissertation Sharif University of Technology Shafaei, Abolfazl (Author) ; Akbari Jokar, Mohammad Reza (Supervisor) ; Rafiee, Majid (Supervisor) ; Hemmati, Ahmad (Co-Supervisor)
    Abstract
    In classical vehicle routing problems, a fixed and specific location is considered for each customer, which in many cases does not reflect reality. Many customers change their locations when distribution is carried out, and in some cases, it is challenging to predetermine their locations. This thesis proposes and develops the Vehicle Routing Problem with Mobile and Stochastic Customer Locations (VRP-MSCL), a subproblem of last-mile delivery. The concept of mobile and stochastic customer refers to a type of customer who is constantly moving, lacks a fixed location, and cannot be identified in advance; however, forecasting customers’ locations in advance is possible. This concept introduces a... 

    Sole versus dual-sourcing under order dependent lead-times and prices [electronic resource]

    , Article Computers And Operations Research, Published in: Elsevier Journals ; Volume 36, Issue 12, December 2009, Pages 3272–3280 Sajjadieh, M. (Mohsen) ; Eshghi, Kourosh ; Sharif University of Technology
    Abstract
    In this paper, we consider a dual-sourcing model with constant demand and stochastic lead times. Two suppliers may be different in terms of purchasing prices and lead-time parameters. The ordering takes place when the inventory level depletes to a reorder level, and the order is split among two suppliers. Unlike previous works in the order splitting literature, the supply lead time between vendor and buyer as well as unit purchasing prices is considered to be order quantity dependent. The proposed model finds out the optimal reorder point, order quantity and splitting proportion, using a solution procedure. Numerical results show that neglecting the relationship between ordering batch size... 

    Human serum protein adsorption onto synthesis nano-hydroxyapatite

    , Article Protein Journal ; Volume 31, Issue 2 , February , 2012 , Pages 150-157 ; 15723887 (ISSN) Mohsen Nia, M ; Massah Bidgoli, M ; Behrashi, M ; Mohsen Nia, A ; Sharif University of Technology
    2012
    Abstract
    Adsorption of human serum proteins (Albumin and total protein) onto high purity synthesis nano-hydroxyapatite (HA), Ca 10(PO 4) 6(OH) 2, has been studied in a wide temperature range by UV-visible spectrophotometer. Adsorption isotherm is basically important to describe how solutes interact with adsorbent, andiscriticalinoptimizing the use of adsorbent. Inthe present study, the experimental results werefitted tothe Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (DR) models to obtain the characteristic parameters of each model and square of the correlation coefficients (R 2). According to the results, the DR isotherm model had the best agreement with the experimental data. The effect of... 

    Effective Permeability of Isotropic Overlapping Sandbodies in 2D Using Percolation Theory

    , M.Sc. Thesis Sharif University of Technology Fatemi, Amin (Author) ; Masihi, Mohsen (Supervisor)
    Abstract
    Permeability is an essential parameter used for reservoir evaluation, simulation and management to optimize oil recovery. The conventional approach to estimate reservoir connectivity, conductivity, sweep efficiency and other critical information for decision-making is to build detailed geological models, which are then upscaled to a coarser grid where flow simulations are run. However, this takes many hours to be carried out even for a single realization practically. In practice, a very small number of realizations are considered and consequently the true uncertainty in the results is very poorly estimated. In this study, a statistical model of isotropic overlying sandbodies is used to... 

    A Metabonomics Study of Samples of Different Diseases: Investigation of Linear and Non-Linear Model by Nuclear Magnetic Resonance

    , Ph.D. Dissertation Sharif University of Technology Fathi, Fariba (Author) ; Tafazzoli, Mohsen (Supervisor)
    Abstract
    Metabonomics is a quantitative measurement of time dependent metabolic interactions for living systems in response to the pathological or genetic variations. NMR spectroscopy has emerged as a key tool for understanding metabolic processes in living systems. In this project, the study of metabolomics was performed as classification and regression on samples of parkinson’s disease, multiple sclerosis disease, celiac disease and crohn’s disease. In classification part, various methods were applied using optimal parameters.classification methods in Parkinson’s disease, multiple sclerosis disease, celiac disease and crohn’s disease were RF, CART, PLS-DA, RF and RF respectively. Based on the... 

    Determination of Parameters Affecting the Linear Seismic Evaluation of Gravity Dams Using Nonlinear Analysis

    , M.Sc. Thesis Sharif University of Technology Monazzam, Arash (Author) ; Ghaemian, Mohsen (Supervisor)
    Abstract
    Gravity dams are solid concrete structures that maintain their stability against design loads from the geometric shape and the mass and strength of the concrete. Because of their critical role in supplying portable and agricultural water and problems which would happen if they broke, it is required to consider their stability and keep them in safe conditions. They should be able to continue their function after a disaster such as earthquake. But most of them are aged dams with some have been built near faults. Indeed, there are some concerns regarding the performance of these dams under the effect of seismic loads. This research deals with performance evaluation of concerete gravity . The... 

    Numerical Analysis of Soil-Nailed Walls in Seismic Condition

    , M.Sc. Thesis Sharif University of Technology Hazeghian, Mohammad (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    Soil nailing is an in-situ technique of mechanically stabilizing soil masses which has been used in France, Germany, United states, and recently in Iran. A review of literature shows that Soil-Nailed walls have performed well during strong ground motions in comparison with the gravity retaining structures. After the 1989 Loma Prieta earthquake, minor signs of distress or corresponding deformation were found on the Soil-Nailed walls, indicating excellent performance of such structures during moderate and strong shakings. These observations indicate that Soil-Nailed walls have an inherent satisfactory seismic response. This has been attributed to the intrinsic flexibility of the Soil-Nailed... 

    Collapsible Behavior of Gorgan Loess Using Odeometer

    , M.Sc. Thesis Sharif University of Technology Zamani, Atefeh (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    In nature, there are types of soils that when goinging under stress at constant moisture, or increase of moisture at constant stress, or change of both characters, they show a sudden and high level decrease in their volume. These type of soils are named as Collapsible soils. Iran is one of the countries that at some parts of its land collapsible soils are found. In this research by using of laboratory equipments, the volume change behavior of collapsible loess soils of Gorgan plain (North of Iran) is evaluated under increase of water content and inundation stress. In these experiments, the usual odeometer cell has been used for exploring the behaviour of collapsibility and volume change of... 

    The Effect of Cementation by Lime on Collapsible Soils Behavior Using Suction Controlled Oedometer Device Case Study: Loess of Gorgan

    , M.Sc. Thesis Sharif University of Technology Zabihi, Nina (Author) ; Haeri, Mohsen (Supervisor)
    Abstract
    Collapsible soils such as loess, which are naturally found unsaturated, are kind of problematic soils that undergo sudden and noticeable decrease in volume under increasing stress at constant moisture, increasing moisture at constant stress, or increase in both of them. This kind of soil can be found in some parts of Iran such as plain of Gorgan. To fulfill the main purpose of this study, evaluating the effect of cementation on collapse behavior of loess of Gorgan, some oedometer tests under controlled matric suction were performed on reconstituted samples without and with lime. The lime was added for stabilizing of the collapsible materials and the amount was chosen to be %3 by weight of... 

    An Experimental Investigation of Three-Phase Flow of water-Oil-Gas Mixture Through Water-wet Sandstone

    , M.Sc. Thesis Sharif University of Technology Javanbakht, Leila (Author) ; Masihi, Mohsen (Supervisor)
    Abstract
    Accurate prediction of relative permeability for various reservoir rocks at various saturation conditions has been of concern for a long time in petroleum industry. Relative permeability is known as one of the most significant parameters in simulation of actual multi-phase flow through porous media during life-time of a hydrocarbon reservoir. In addition, it plays important role in oil production and well completion. Direct experimental measurement in order to determine relative permeability of porous rock has long been recorded in petroleum related literature. However, empirical methods for determining relative permeability are becoming more widely used, particularly with the advent of... 

    Introducing a Set of Material Strain Measures in Non-Linear Kinematics of Micropolar Continuum Mechanics and Determining their Time Rates

    , M.Sc. Thesis Sharif University of Technology Ebrahimi, Mehran (Author) ; Asghari, Mohsen (Supervisor)
    Abstract
    The concept of generalized strains is a well-established subject in the classical continuum mechanics. The characteristics and various applications of the generalized strains have been the point of interest of many researchers in the classical continuum mechanics. The aim of this thesis is the introduction of generalized strains in the micropolar theory, as a non-classical continuum theory. A set of generalized strains is suggested for the deformation of macro-elements. Moreover, a set of generalized strains is proposed for the micro-structures. Since the rate of strains possesses a significant importance in the constitutive equations of nonlinear analysis of solids, expressions for the rate...