Sharif Digital Repository

Human brain is one of the most wonderful complex machine which is designed for ever. A huge complex network, composed of neurons as tiny biological and chemical processors which are distributed and work together as a super parallel system to do control and vital activities of human body. Today the main secrecies of operation mechanism in individual neurons as fundamental elements of brain are reasonably understood, but network interactions of this wonderful processors and full understanding of information coding in brain seems elusive and remains as a big challenge in many interdisciplinary fields of science, from biology to cognitive science and engineering.
Thus human brain learning... 

Liquefaction-induced lateral spreading is one of the most challenging problems in geotechnical earthquake engineering. This phenomenon may impose severe damages on deep foundations in large earthquakes. In this study, six physical modeling are designed, built and tested to investigate the effects of lateral spreading on deep foundations and also assess one mitigation method. The experiments were conducted using 1g shake table of Sharif university of technology. In this respect, a large laminar shear box with outer dimensions of 420, 240 and 180 cm was designed and constructed. The laminar shear box consisted of 23 steel laminates with inner dimensions of 306×172 cm. Four experiments were... 

Wildfire in natural habitats is a common natural disaster that can have natural or human origins. With the increasing global temperature and consecutive droughts, the number and intensity of these fires are increasing. In our country, due to a lack of natural resources and recent droughts, the importance of preventive measures in starting and effectively extinguishing fires is increasingly felt. Nowadays, with the increase in computational power, numerical methods have come as the aid of physical models to predict the spread of fire and have become a worthy replacement for experimental tests due to the destructive nature of fire. In this research, we have investigated the effect of main... 

Loads from laterally spreading ground have been a major cause of damages to pile foundations in past earthquakes. Analysis of case histories have shown that damages are particularly intense when a nonliquefiable surface crust layer spreads laterally over underling liquefied layers. In this research the effect of lateral spreading due to liquefaction on single piles embede in a gently sloping ground has been investigated. Finite element method using OpenSees is used to model the pile and embedded soil. The soil profile for all models consisted of a nonliquefiable crust layer overlying loose sand with Dr = 30-35% overlying dense sand with Dr = 70-80%. The effect of geometric properties such as... 

Complex networks have recently become a very noticeable subject because of their remarkable theory on real networks such as rumor spreading. This thesis contributes to a prevention strategy which uses a maximal clique algorithm to find overlapping communities and also uses inverse targeting immunization strategy to immune these communities. By the using maximal clique algorithm combined with inverse targeting strategy we have achieved that the TIK method (targeted immunization using k-clique percolation) obtains 10% of better immunization than HD (highest degree) method which is one of the best methods in targeted immunization strategies. The TIK also demonstrates that rumor spreading is... 

Social networks play a fundamental role as a media for the spread of inuence among its members. How people like to adopt innovation from their friends is known as word-of-mouth eect and has a long history of study in social science and recently in computer science and mathematics. In this context, The Inuence Maximization Problem is about nding initial active set of specic size in order to maximize the nal adoptions in the network through diusion of inuence. The optimization problem of the most inuential nodes selection is NPhard. As a result, some heuristic algorithms are needed to approximate the nal result. In this thesis some new heuristic algorithms were proposed with respect to... 

During the past earthquakes in all over the world, the piles have had serious damages in soils with liquefaction potential. During an earthquake, liquefaction occurs in some parts of ground with mild slope and saturated and soft granular soil. Afterwards lateral spreading induced by liquefaction incurs irreparable damages on structures and piles particularly. Observing these damages, the researchers and engineers have conducted more surveys and investigations to studying the behavior of piles in granular soils with liquefaction potential and also interactions between  soil  and pile.  In  these  researches,  they have  modeled  the  interactions between  soil  and pile.  However  there are ... 

A social network is a social structure made up of individuals (or organizations) called ”nodes”, which are tied by one or more specific types of interdependency. These networks are new forms of distributed larg media which actually plays a critical role in distributing information and news among the people. because of the size and autonomos aspect of these kind od medias, taking control of them seems impossible. with the best hope we could think of some ways to detect information cascades through network.for example we could select a set of nodes as sensor inorder to detect information cascades as effectively as possible. in this thesis we studied cascade detection problem in scenario based...