Sharif Digital Repository

Nowadays, most of businesses are becoming computer-based. This trend causes the organizations to become more vulnerable to internal and external threats. Internal threats are done through insiders. Insiders unlike outsiders have capabilities which aid them to easily carry out their illicit activities. Unfortunately, most of research in computer security has focused on the outsider threats, whereas the most damaging is the result of insiders’ illicit activities.This dissertation addresses three primary necessities of the research in the area of insider threat: a consistent definition of insider threat, a classification of types of insider threats, and a classification of vulnerabilities which... 

Banks and financial services typically focus on geographic, demographic, socio-economic, and psychological characteristics to segment the market, in spite of the fact that these are not efficient predictors of future buying behavior of customers. In the present study, benefit segmentation has been used to group retail banking customers in relation to their particular attitudes and behavior. In particular, the identification and measurement of the two major dimensions of service quality, process (how the service is delivered) and outcome (what is delivered) have been investigated to better understand of what constitutes service quality from the customer’s viewpoint. In order to derive... 

Due to the dynamic topology of vehicular ad hoc networks, routing of packets in these networks faces a lot of difficulties. The situation will become more challenging when we have to deal with Delay Tolerant Networks (DTN) which are also sparse and partitioned and we need to use some vehicles to store the packets and carry them from one partition to another. Despite all these difficulties, by looking through movements of vehicles in an urban environment, we can find out that the topology of the network does not change in a pure random way and we can bring the traffic models of streets into account for having better routing performance. In this thesis, we proposed an intelligent routing... 

In this project, Fe3O4 nanoparticles were synthesized and coated with different polymeric materials for drug delivery application. For this purpose, water dispersible oleic acid(OA)- pluronic block copolymer coated magnetite iron oxide nanoparticles were synthesized that can be loaded with proper doses of cephalexin. Our data indicated that formulation of iron oxide nanoparticles was developed by optimizing the amount of oleic acid required to coat iron oxide nanoparticles and then by optimizing the amount of pluronic required to form an aqueous dispersion of oleic acid coated nanoparticles. Synthesis of magnetite nanoparticles was done by the addition of a strong base (NH4OH) to ferrous... 

In this work, a comprehensive survey on the different methods of modeling fluidized beds was done. Finally, the discrete particle method with soft particle approach was selected as the method of modeling the solid phase. For the gas phase, computational fluid dynamics (CFD) as the method of modeling is used. In order to verify our simulation results for the solid phase, a simulation of a bed with many particles distributed all around the bed was done. At the first second of the simulation, the gas phase flow was truned off and the particles were falling down. The results obtained with this method were verified with the references. For verification of the gas phase, a 2D bed with the gas... 

Fire is one of the most important events in nuclear power plants which has a large share of total core damage frequency. For example, the core damage frequency in Bushehr nuclear power plant from fire accidents is 6.1E-6/ year which is equivalent to about 63 percent of core damage frequency from all internal accidents. However, due to the unavoidable presence of flammable materials, e.g. Electrical equipment, cables, gas, flammable liquids, …), it is impossible to prevent fires in these plants . Fire at nuclear power plants may be caused directly or indirectly by one or more initiating events, which the following accidents in turn would threaten the safety of the plant. In this project,... 

Station Blackout (SBO) involves Loss of Offsite Power (LOOP) concurrent with failure of the onsiteemergency ac power system. Although SBO is a beyond designbasis accident, in recent years this accident attracts a lot of attention. Fukushima nuclear accident which was initiated by earthquake followedby tsunami led to a SBO accident. In this thesis, Probabilistic Safety Assessment (PSA) is applied to analyze SBO in IR-360 nuclear power plant and to compute its frequency. Meanwhile, weak points of the plant are identified in order to minimize the SBOprobability of occurrence. Fault tree method is used to evaluate emergency power system and offsite power system reliabilities. Common Cause... 

In this M.Sc. thesis dynamics of a system of 3-D fluid (internal) and solid interaction hase been studied. Structure (shell) filled with dense fluid (liquid) and it is under large amplitude vibrations excitations. Shell is analized using geometrical nonlinear general shells formulations. The nonlinear analysis includes large displacements, large rotations and large strains without considering material nonlinearity. Based on the potential flow assumption the governing equations of fluid are derived. And using boundary elements formulations fluid hydrodynamic pressure in each step is drived. In order to simultaneous and mutual influence of fluid and structure, numerical model of combined...