Sharif Digital Repository

The emergence of online social networks (OSN) has encouraged scientists to investigate them more deeply due to availability of excessive data and increased computational power. Diffusion is a fundamental process taking place in such networks. The spread of news, ideas, influence and diseases are examples of diffusion in social networks. The importance of information diffusion in different disciplines such as economics, politics and social behavior has motivated us to study diffusion networks in this thesis. Diffusion’s behavior is strongly influenced by the underlying network in social networks. Despite this fact most research done in this area ignores the dynamics of the underlying network.... 

The purpose of writing this thesis is to arrive at the concept of civilization. And in this process, using the constructive perception. My approach in constructive perception is different with approach of Allameh tabatabaei in constructive perception. In first chapter defining constructive perception as the perception that mind by analogy between two consepts makes the non-real relations and attributes it deliberated to the reality (the parties). Meanwhile, should have been constructive perception is the intermediary that stimulation our sense abut reality. These feelings can be tenderness or hatred or fear and hope and ... . In the second chapter we will show that the use of technology... 

Loosening and gap opening at the bone-implant interface depends on several physiological and mechanical factors such as bone remodeling, stress concentration, and variation in load transfer pathway. Since fracture of orthopedic material at the interface is one of the major failure mode of total joint implants, this study focused on the micromechanical behavior of the interface. Using a two-dimensional FE model, with pure compressive, tensile, and shearing forces applied on bone or cement, ratio of the stress at the interface to the applied stress has been calculated. Stress distribution was considered as a function of porosity,angle of bead contact to surface, as well as size of bead for two... 

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... 

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... 

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... 

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...