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...

Numerical Study of Geotextile Application in Downstream Filter Zone of an Embankment Dam with Clay Core

, M.Sc. Thesis Sharif University of Technology Maghsoodian, Maedeh (Author) ; Shamsaie, Abolfazl (Supervisor)

Abstract

Nowadays, applications of the synthetic materials are developing in civil engineering projects and widely used in these projects. Therefore, during previous years; use of the Geotextiles as one of the Geosynthetic materials in order to filtration, drainage, separation, soil protection, etc have developed ever-increasing. The goal of this research is modeling and studies of the Geotextiles application in the downstream filter zone of embankment dams in combination with granular materials using FLAC2D software. Gordeh Bin embankment dam situated in West Azerbaijan province has been chosen as case study. In this matter, different models have been made with changes in thickness of the inclined...

groundwater level fluctuations forecasting using conjunction models of Wavelet - Neural-Fuzzy Network (WNF) and Wavelet-Neural Network (WNN) and linear model of ARIMA (case study: Qom plain

, M.Sc. Thesis Sharif University of Technology Fathi, Bahman (Author) ; Shamsaei, Abolfazl (Supervisor)

Abstract

Prediction of groundwater level fluctuations is absolutely necessary for the proper manag ement of these precious resources. There are different methods to predict hydrological time series such as groundwater level. Linear models inefficiency in predicting nonlinear and n on-stationary time series cause researchers widely use artificial intelligence techniques such as Artificial Neural Networks (ANN), Fuzzy Inference System (FIS), Genetic Algorithm (GA) and their hybrid models such as Artificial Neural – Fuzzy Inference System (ANFIS). These smart models are capable to simulate nonlinear and non-stationary time series in suitable accu-racy using by a few time and data. By emersion of Wavelet...

, M.Sc. Thesis Sharif University of Technology Nazari, Fatemeh (Author) ; Shamsaei, Abolfazl (Supervisor)

Abstract

Entrance of air to close water conduits occurs in many ways. This phenomenon makes displeasing effects on water transport structures. Two-phase flows in closed conduits are studied experimentally, numerically and theoretically. Even after decades, due to the complexity of the subject, these studies still require development and reformation. Numerical and theoretical two-phase models are often limited to a special regime of flow."Volume Of Fluid"(VOF) is a model for non-mixing two-phase flows. "Fluent" software uses this model in this field of flows. Volume of fluid is used successfully in some problems like dam break or rising bubbles. Main disadvantage of this model is distribution of the...

Assessment of waterlogging and provide risk maps by using RS, GIS and field data (case study: Qazvin plain)

, M.Sc. Thesis Sharif University of Technology Mansourian, Hamid (Author) ; Shamsaei, Abolfazl (Supervisor)

Abstract

Groundwater quality protection has a significant importance due to abundant applications of these resources in various fields such as agriculture, industry and drinking water. Removal of groundwater pollution is a time and money consuming process and often pollution is detected when improving the quality of groundwater is nearly impossible. For this vulnerability assessment there are three methods: Processing, Overlap-Index and Statistical Methods. Overlap-Index is composed of variety of maps such as Geology, Soil, Groundwater Depth and etc which uses in determining of vulnerability Index. In the present study for underground pollution potential determining, four indexes such as AVI، GOD،...

Efficient Management of River Water Quality Based on Pollution Trading Approach

, Ph.D. Dissertation Sharif University of Technology Sarang , Amin (Author) ; Shamsai, Abolfazl (Supervisor)

Abstract

“Sustainable development” is a frequently used phrase, but the idiom has been experienced little since it was coined by the Brundtland, due to its intrinsic complications. The issue is going to compromise two key components; economy and ecology. One of the solutions based on concept of sustainable development that has been proposed for maintaining water quality at acceptable levels is to cap pollutant emissions at a sustainable level, then establish an economic market in which the right to discharge pollutants is traded according to market supply and demand mechanisms. Water quality trading or pollution trading is one such kind of market-based program that has also been described using names...

Semi-supervised Breast Cancer Subtype Clustering Using Microarray Datasets

, M.Sc. Thesis Sharif University of Technology Vasei, Hamed (Author) ; Motahhari, Abolfazl (Supervisor)

Abstract

Gene expression microarrays can be used for precision medicine and targeted therapies. The data generated by microarrays are high-dimensional causing statistical inference of any parameter a daunting task. In this thesis, it is shown that regardless of high-dimensional datasets produced by microarrays, the inference can be robust in the sense that random selection of features results in the same conclusion as far as the number of selected features are chosen appropriately. Stratifying patients with breast cancer based on their gene expression levels shows that patient subtypes are almost independent of the feature selection strategy. Moreover, using less noisy datasets coming from RNAseq...

A Simulation for Better Understanding of Integrin Clustering and Activation

, M.Sc. Thesis Sharif University of Technology Shams, Shahab (Author) ; Motahhari, Abolfazl (Supervisor)

Abstract

Today, computer simulations are employed prevalently by researchers to understand biological processes. The tendency to use computational methods has been increased recently due to the high costs and errors of experimental methods. Integrins are membrane proteins that mechanically attach cells to the extra cellular matrix (ECM) and derive some behaviors such as cell migration. Moreover, integrins have biochemical functions. They transduce environment signals and trigger chemical pathways. As a result, integrins regulate cell shape, motility, etc. The investigation of integrin behavior in a real environment is very difficult due to the presence of many other proteins that interfere with the...

Hydro-economical Method for the Optimal Capacity Design of Small Hydropower Plant (Case Study: Kohneh Lahijan Hydropower Plant)

, M.Sc. Thesis Sharif University of Technology Mehrvand, Shahryar (Author) ; Shamsai, Abolfazl (Supervisor)

Abstract

In this thesis, we determine the optimal capacity of the power plants considering site specifications and Flow Duration Curve and evaluating economic parameters. Finally a design with more sufficient economical and hydrualical performance would be selected. The optimization algorithm used in this thesis is called "Charged System search" that is one of the newest meta-heuristic algorithms. This algorithm is inspired by the coulomb and gauss's laws of electrostatics in physics and utilizes a number of charged particles which influence each other based on their fitness values and their separation distances considering the governing law of coulomb.The proposed method in this thesis can be...

GIS Based Procedure to Determine Location of Cascade Small Hydropower Plants Case Study, Nokhan Area

, M.Sc. Thesis Sharif University of Technology Serpoush, Behrad (Author) ; Shamsai, Abolfazl (Supervisor)

Abstract

Coinciding with the worldwide environmental issues and increasing demand for clean energy sources, hydropower plants have highly attracted decision- makers attention. Low manufacturing costs and pollutions which are made by these plants in comparison with another types of powerhouses, could be reason of that. And so on, hydropower locating and evaluating studies have been highly increased recently, specifically in developing countries. From the point of operation procedure, hydropower plants are generally divided in two types, run-of-he-river and storage projects. This study has concentrated on run-of-he-river projects and due to spotting plant location, Sefidbarg river basin...

Investigation of bed Stability in Downstream for the Diversion dam under Scour (Mill & Moghan case study)

, M.Sc. Thesis Sharif University of Technology Gorji, Faeze (Author) ; Shamsai, Abolfazl (Supervisor)

Abstract

Numerical simulations and large eddy simulations (LES) of turbulent flow downstream of diversion dam , pool-riffle bedform in different geometrical ratios (different lengths of riffle and pool) with flow Reynolds number of 3.0 E+04 to 3.3E+04, downstream of special case study "Mill and Moghan diversion dam" with Froude number of 0.5 are presented The calculations are performed using a computational fluid dynamics model, FLOW-3D, which solves the Navier-Stokes equations in three dimensions with finite volume method. Numerical simulations are validated by comparing the numerical results of time-averaged flow patterns downstream of pool-riffle sequence with that of the experimental...

Assessment of Optimum Environmental Flows Using Economic Evaluation Methods

, M.Sc. Thesis Sharif University of Technology Mazdarani, Sohrab (Author) ; Shamsai, Abolfazl (Supervisor)

Abstract

One of the main challenges of Water Resources Planning and Management (WRPM) is to balance water allocation between different uses. Usually, due to political and economic power of other uses, ecosystem receives less attention. Environmental flow is the allocated flow to ecosystem. Ecosystem provides a wide range of services to humanity. Therefore, environmental flow is not exclusively a matter of sustaining ecosystem but also a matter of providing humans with better life. Several methods have been developed to determine the environmental flow but only a few consider its socio-economic aspects. Consideration of these aspects could assist decision-makers with determining the optimum flow and...

Application of Gis & Fuzzy Technique for Order-Preference by Similarity to Ideal Solution (Topsis) in Siting Water Reservoires

, M.Sc. Thesis Sharif University of Technology Jozaghi, ali (Author) ; Shamsai, Abolfazl (Supervisor)

Abstract

Sustainable agricultural development in the country without regard to water supply problems in terms of time and place is not possible. Construction of water storage tanks filled with water and seasonal use in dry seasons in the effective action in the optimal use of water in the climate of (low and irregular rainfall) is. The most important step in the construction of water storage tanks to choose the best point for the construction of the reservoir basin in order to reduce costs and increase efficiency. Chndmyarh different methods to decide the best option for finding a few options from there. Among these methods can be Tapsys two methods (TOPSIS) and hierarchical analysis (AHP) pointed...