Sharif Digital Repository

In this thesis, I am going to review an introduction of scattering amplitude as a recently hot subject.First of all, I will introduce spinor representation and its applications to calculating scattering amplitudes. After that, I will focus on the MHV amplitudes as an Impressive part in simplifying scattering amplitudes. Then, I am going to speak about CSW and BCFW; some powerful toolkits in calculating scattering amplitudes of Yang-Mills theories, and I will show the power of these methods in simplifying the complexities in scattering amplitudes. Finally, I am going to speak about the amplitudes and super amplitudes in N=4 Super Yang-Mills theories and we will touch their amazing simplicity... 

Entanglement is an immediate consequence of quantum mechanical pos- tulates and is thus an indispensable part of studying quantum systems. A very useful quantity which can appropriately quantify entanglement between the degrees of freedom of a composite quantum system is En- tanglement Entropy (EE).
Over the last few years, this subject has attracted a lot of interest both in QFT and in the context of holography. On the one hand, an intu- itive geometrical Holographic model for entanglement entropy has been proposed in the context of gauge/gravity duality, and on the other, var- ious issues concerning entanglement have been explored, e.g. in quan- tum computation, quantum information... 

This study has been carried out for investigating the need for an appropriate and fast seismic analysis method to be applied in performance based design (PBD), and show the application of Endurance Time (ET) method and it’s advantages in PBD. Necessary theories were generated in hazard analysis, bi-directional seismic analysis, introduction of dynamic push-over curve and application. As a secondary goal, potential of this method in more complicated nonlinear domains is assessed. Application of ET and its advantages in PBD is shown with an example of SMF, NDCBF, CBF and BRBF building after modeling nonlinear interactional behavior of beams and columns, and also modeling buckling and... 

Following a large earthquake, numerous aftershocks can be triggered due to the complex stress interaction between and within tectonic plates. The aftershocks have the potential to cause severe weakening of mainshock-damaged buildings, threaten life safety, hamper reoccupation and restoration of buildings, and increase financial loss. The probability of aftershocks has not been included in the description of seismic hazard in performance-based earthquake engineering. This study proposes methodologies and a framework to investigate the seismic performance in the lifetime of steel MRF structures subjected to mainshock-aftershock sequences. The case studies correspond to three SAC 2D steel MRF... 

The aim of this research is to evaluate and compare the performance of common concrete and steel structural systems in the construction industry under various parameters, including initial construction cost, lifetime seismic losses, end-of-life costs of the structure, and simultaneous consideration of these parameters. In this regard, a residential building with real architectural plans and details was designed for five different structural systems, both concrete and steel, and their initial construction costs were calculated using executive drawings. Then, using Endurance Time dynamic analysis, the structural responses under probable seismic hazard levels was determined, and based on... 

One of the main challenges in the design of wireless sensor networks (WSNs) is minimizing the energy consumption while simultaneously maximizing the performance of sensors. In this thesis, we have considered WSNs based on beacon enabled IEEE 802.15.4/Zigbee Standards with low rate applications like temperature, humidity and light sensing, which mainly have been used in a smart home environment, and proposed a cross-layer design to overcome this challenge. The design involves an optimizer module that captures the application layer and MAC sub layer behaviors. Based on these behaviors, the optimizer dynamically changes the rate of node’s traffic at the application layer and the priority of... 

We present a home energy management system that is able to manage home energy demand and resources to achieve minimum household payment in electricity dynamic pricing.Communication is used to collect needed data from the home energy system members and users in order toimprove demand and resources management. Some of the needed data comes from appliances and solar panels by wireless sensor network and some other is received from home users by a user interface.
Two algorithms are proposed that the first algorithm goal is to minimizing household payment and the second algorithm goals are flexible implementiation and decreasing household payment. To decrease household payment, these... 

Today, smart devices have become an integral part of everyday life. The Android operating system is also the most popular operating system of these devices, and as a result, various malwares are produced and distributed for this operating system every day. This makes it especially important to investigate these malwares. This includes finding people involved in the development and distribution of malware, as well as discovering other malwares created by them. Discovering other involved entities, such as social media accounts, websites, Android store accounts, and taking steps to prevent malware from being distributed by them is another aspect of this story. In order to deal with organized... 

Exact and safe structural analysis and design under various loadings is an important issue, which have engaged engineers for a long time. Till now, building design codes have suggested three main methods for seismic analysis of structures, which consist of: Static analysis, Pseudo-dynamic response spectrum analysis and Time history analysis. The first two methods are too approximate, especially in irregular structures which demand exact 3d analyses. The most reliable method is Time history method. With advance of computational tools, engineers tend toward using more reliable analysis methods and using old fashioned rough methods is becoming less popular. One of the issues, which is important... 

Recent studies show that irregular structures have been damaged more than regular ones during earthquakes. This proves importance of seismic response determination of this type of structures. Today, Codes define irregularity in structures and restrict seismic analysis and design of these types of structures. The Endurance Time (ET) method is a time-history based dynamic pushover procedure for seismic analysis and design of structures that has been recently proposed in Sharif University. This thesis illustrates ET capability in analysis and design of vertically irregular frames. Irregular frames with three, seven and twelve story high were designed with two types of mass and stiffness... 

In this research the appilication of a new method named Endurance Time (ET) analysis in seismic analysis of multi span bridges in linear and nonlinear ranges is investigated. Endurance Time is a time history based method of seismic analysis. In this method structure is subjected to an intensifying predefined acceleration function and different damage indices of the structure are evaluated through analysis time. The Endurance Time criterion and the Endurance Time acceleration functions have been generated in previous researchs of ET group. Using 7 earthquake records which are selected from hundred ones of PEER database based on FEMA p695 recommendations, several scaling methods are used to... 

Endurance Time Method (ET) is a type of dynamic pushover procedure in which the structure is analyzed under special series of accelerograms, called ET acceleration Functions (ETAF) and the response of structure is sketched versus time until the collapse state. With evaluating response curve and the time which damage in structure reach the expected value, the final assessment of structure can be made. In this dissertation, the application of ET method for Non-linear 3 dimensional seismic analysis of steel moment frames under earthquake multicomponent excitation is investigated. For this purpose, various patterns of ET loading are investigated and the most appropriate algorithm in...