Sharif Digital Repository

Recent violation of security properties of e-voting protocols not using provable security, indicates the importance of provable security. In this thesis, we use the provable security approach to analyze security properties of e-voting protocols.In addition to presenting an efficient and provably secure protocol, the minimal assumptions to achieve privacyin e-voting protocols are analyzed. The firstcon-tribution of this thesis is presenting an efficient and provably secure coercion-resistant protocol, which is a variant of the JCJ e-voting protocol (Juels et al.,2010). It decreases the total number of JCJ’s operations fromO(n2) to O(n). The second contribution of this thesis is proving the... 

Airport Traffic Control Towers (ATCTs) are among the most critical structures in an airport that are expected to keep their level of serviceability after severe strong earthquakes. Therefore analysis and design of these structures need a detailed investigation on the seismic behavior of the structure based on the structural characteristics. In this study three different existing reinforced concrete ATCTs have been investigated. As important parameters of earthquake design of structures, response modification factor (R-factor) of these towers will be determined. R-factor reduces elastic force level to design force level and contains the effect of ductility, overstrength. In Iranian seismic... 

Controlling the nonlinear processes is very important in industry. In this thesis, model predictive control is considered as a nonlinear control strategy and two nonlinear models, namely wiener and Hammerstein models are used and their identification methods are described. State-space model is also considered and closed-loop stability has been studied. Another strategy for controlling the nonlinear process is global linearization control. Some concepts and related theorems for this strategy are stated. PID controller is used as a linear controller for this strategy. In this model for estimating the state and load, two nonlinear observers are used. Stability analysis of output feedback... 

The objective of this thesis is to investigate the application of graph theory in managing emergency evacuations of passengers from airplanes and space stations. Given the critical importance of passenger safety and the necessity for optimized design of emergency evacuation routes, this research aims to provide a mathematical and analytical framework to reduce evacuation time under critical conditions. Common methods in this field are typically based on costly and time-consuming simulations that require significant financial and temporal resources. Instead of relying on these approaches, this study explores the application of analytical and mathematical methods, particularly graph theory.... 

In this research, initially the Glycerol liquid membrane with dissolved sodium carbonate carriers, which is supported by CA porous filter, was prepared. The effects of Na2CO3 concentration and pressure difference on gas permeability were investigated. Permeability of CO2 and N2 were measured at pressure difference of 0.7, 1.6, 2.1 and 2.8 bar with carbonate sodium concentration of 0, 1 and 2 mol/lit. Permeability of CO2 was found to be higher than N2. Increasing the pressure difference resulted in an increase in the N2 permeability coefficient while decreased the CO2 permeability coefficient. Increasing the concentration of sodium carbonate increased the CO2 permeability drastically but... 

Numerous research is available in the literature regarding shear walls. These have considered parameters like wall cross-section, Reinforcement configuration, boundary elements, etc. In addition, seismic and wind loading behavior has been discussed. Currently, the software ETABS is used extensively in automatic design of shear walls, The programs design bases are investigated in this thesis in ragards to flexural, shear and boundary elements of shear walls under seismic loading. The attachment of wall elements to frame (column) elements is of particular interest in this study  

With development of electronic payment infrastructures and increase of payment transactions in result, abusing these infrastructures and fraudulent efforts has been increased. Problem of “Fraud Detection in Financial Transactions” is finding these illegal/abnormal transactions while many other legitimate transactions exist. Goal of this thesis is providing a method for fraud detection in financial transactions using representation learning. Many approaches are used for solving fraud detection including classic data mining algorithms and deep learning based methods, which are compared in this thesis. We also covered diverse feature engineering and representation learning ideas for improving... 

Multistatic radar has several advantages over monostatic radar (such as better detection), which are due to the use of different viewing angles and the difference in their clutter characteristics. Clutter in many applications (such as marine applications) has the property of being sparse in certain dictionaries. Therefore, the investigation of sparse clutter (such as sea clutter) is of particular importance. It is worth noting that the detection of targets in the vicinity of the sea faces difficulties due to the dynamics of the sea, which causes the Doppler spectrum to change with time and change in space. Considering the fact that the sea clutter is sparse clutter, one of the powerful... 

In most of the engineering applications, the mechanical behavior of materials in high strain rate deformations differs from their behavior in quasi-static deformations. In some engineering problems like impact loading on structures, metal forming and explosive forming, the range of strain rate is about . Taylor impact test is one of the experiments used for characterizing the dynamic behavior of materials in high strain rate deformations. In the Taylor impact test a rigid cylindrical projectile is impacted normally onto a hard and massive surface (anvil), the projectile deforms by mushrooming at the impact end. With plastic wave propagation analysis, the plastic deformation of projectile is... 

Safety is an important factor in the nuclear power plants due to its inherent human and environmental hazards. Therefore, in order to ensure the safety of the plant and proper functioning of its various components, a series of commissioning tests should be conducted according to international nuclear power plants standards, before its operational exploitation. On the other hand, safety of the plant can be guaranteed by modeling transient states and possible scenarios of accidents in different situations. In this study, a commissioning test of Bushehr Nuclear Power Plant (BNPP) and its associated accident is modelled by gathering geometric data and information about the facilities... 

This research uses the new approach of Son (2003) for the decomposition of poverty in Iran into three separate components of growth, inequality and population effects during 2001 to 2007 and meanwhile uses the integration of microeconomic and macroeconomic data together to increase the accuracy of the results. The main question of this research is to determine the orientation of development strategies for alleviation of poverty in Iran, which could be either growth-oriented or inequality-oriented ones. The resultes suggest that the former has always been pro-poor in Iran and has had the most dominant effect. Therefore, in order to decrease the poverty in Iran in the future, there should be... 

With fast improvements of technology in advances in electronic voting systems, has been very effective in substantially reducing the disadvantages of traditional elections and thus enhancing the legitimacy of those being elective. These systems, to be effective,
ought to be designed based on several security factors such as eligibility, correctness, voters' privacy, verifiability and receipt-freeness. One of the most important issues in this concept is ensuring the satisfaction of these properties. Using an incomplete and vulnerable system may cause negative consequences. Therefore, it is necessary to evaluate the system before implementation. Using formal methods for verification of... 

The first physical realization of the missing fourth fundamental element of electrical circuits, namely memristor, in 2008 by HP labs triggered an immense amount of research on the capabilities of this element in implementing artificial neurons and artificial brain. In this project we will propose several reinforcement learning-based algorithms that are implemented on a specific memristor-based structure, the memristor crossbar structure. Hence we provide a learning paradigm that resembles the human learning paradigm not only because of the the algorithmic core, which is based on learning from sparse and delayed rewards and penalties, but also because of the hardware over which the... 

The purpose of this thesis is assessment of seismic performance of self-centering concentric braced frames (SC-CBF). In this structures, the column under tension can uplift from the foundation at a specified level of lateral loading and by using some methods such as post-tensioning (PT) bars or tendons, the structure is able to self-center after severe Earthquakes. In this systems, PT bars and energy dissipation elements resist column uplift. The effect of energy dissipation ratio and initial stress in PT bars was investigated in design and performance of four four-story analytical models. Nonlinear static and dynamic analyses were conducted to compare some parameters in these four models... 

In recent years, one of the most important air pollution in Tehran in terms of creating unhealthy air quality is particulate matter and especially PM2.5. Particulate matter in Tehran is released from various sources. Identification of components and estimating the contribution of each emission sources, helps governers to find air pollution control strategies. To find out major components of PM2.5 in Tehran, a one year sampling to collect PM2.5 was conducted from February 2014 through February 2015 in AQM station at Sharif University of Technology located west of Tehran. 24-hour integrated samples collected on a 1-in-6 day schedule on both Teflon and quartz filters. TOT analysis was done for... 

Soil structures have important roles in civil engineering applications. The most important types of these structures are soil dams and foundations which their damages may cause huge loss. Thus, appropriate analysis of these structures under possible loading conditions is unavoidable. The real behavior of this media can be achieved from the solution of its coupled governing differential equations. In order to solve this set of equations in practical applications, appropriate numerical solutions should be used. The finite element method can be called as one of the most important numerical solutions of differential equations which have been used in analyzing different types of engineering... 

The air distribution is the main factor of contaminant transportation in cleanrooms. The experimental method is the most reliable one for investigation of flow field, which the difficulties associated with it, has limited not only the examination of the flow field in cleanrooms, but also the improvement of their qualities. Most of the experimental researches in indoor air quality concern conventional rooms and do not take into account specific supply-exhaust diffuser configurations, which are used in cleanrooms. Using small-scale models can reduce the complexity and the cost of measurements. In this research, the 3D velocity field of a small-scale cleanroom is measured in three different...