Sharif Digital Repository

Evolutionary game theory is a relatively new branch of game theory (in contrast to the classical game theory) which has overcome some of the common problems of the classical version such as highly rational agents assumption. Because of this, it has gained popularity among different sciences. On the other hand, social network as one of the branches of complex networks is a pretty novel research area and has application in several fields. Networks are everywhere and most real-world networks are complex ones. Group formation and evolution are among important subjects in studying social networks and some works has been done in analyzing and modeling them. In this thesis we have presented a... 

In the first part, we report a new and simple procedure for preparing reduced graphene oxide /nickel, cobalt hydroxide composite (Ni,Co-OH/rGO/NF via a fast and simple two-step electrochemical method including potentiostatic routes in the presence of Cetyl trimethyl ammonium bromide )CTAB( as a cationic surfactant. In the first step, a piece of nickel foam (NF) is sonicated in a suspension of graphene oxide (GO, 6 mg/L) after dried in an oven, reduced by electrochemically. After that, Ni, Co LDH were co-deposited on the surface of rGO/NF. The resulting modified electrode afforded extremely high specific capacitance of 2133.3 F/g at a current density of 4 A g-1. FE-SEM results showed that... 

Aphron drilling fluids or CGA fluids are the wellknown updated drilling fluids in recent years.this kind of drilling fluids can control the mud loss into the formation and thus reduce formation damage and drilling costs. its structure consists of two phase fluid (gas and liquid) that the aphrons are the micro bubbles with 10 to 100 micrometer diameter that have strong stability in liquid phase compared to foamy drilling fluids. Generally aphron drilling fluids are made of base drilling fluid and surfactants, for more stability, mixed surfactant-polymer additive is so beneficial. in the last two decades, the Lattice-Boltazmann method is introduced for computational fluid dynamic area and... 

In this thesis we ascribe a one graph to groups and investigate the relations between groups structure and graph. Let G be a group. The prime index graph of G, denoted by π(G), is the graph whose vertex set is the set of all subgroups of G and two distinct comparable vertices H and K are adjacent if and only if the index of H in K or the index of K in H is prime.Also, The intersection graph of G denoted by Γ(G), is the graph whose vertex set is the set of all non-trivial proper subgroups of G and two distinct vertices H and K are adjacent if and only if H ⋂ K≠ {e}, where e denoted the identity element of G. We denote the complement of Γ(G) by Λ(G). In this thesis we consider the following... 

With the development of artificial intelligence as well as robotics, affective computing which is about recognizing human emotions by machines and creating artificial emotions in them in order to create a proper social reaction is becoming an important topic. Most of the research in this field has been focused on recognizing and detecting human emotions. In this study, assuming a proper understanding of emotions by artificial intelligence models, an attempt has been made to better clarify the emotional space. In more detail, the goal is to examine the changes in the human emotional state in order to gain better control of his behavior. In this study, by analyzing the feelings of users and... 

This research mainly aims to propose, for the first time, a way of generating text from Abstract Meaning Representation (AMR) in Persian. AMR is a rather new way of representing the meaning of natural language sentences, that captures the various semantic components in a rooted, directed, acyclic graph. Generating text from AMR is a challenging task in natural language processing as some syntactic constructs are abstracted away from the representation, resulting in one single AMR having multiple translations. Considering many applications of generating text from meaning representations in natural language processing it seems inevitable to design some methods for converting such... 

The emergence of lexical knowledge bases such as WordNet and FarsNet foregrounded the importance of semantic annotation of words in the areas of natural language processing and corpus linguistics. The methodology in these knowledge bases is based on semantic relations and dictionary definitions of the words in coverage. Another efficient way to perform semantic annotation is by semantically classifying the lexicon of a language in a taxonomy. In this research, we build a semantic annotation system for the semantic tagging of Persian texts. This system can be used for building tools and softwares for natural language processing in applications such as text summarization, plagiarism detection... 

The Ni-base superalloy CM88Y has good hot corrosion resistance, high stability and strength at elevated temperature; accordingly, the alloy is used in manufacturing of gas turbine hot components. In most applications, heat treatment is required in order to achieve the desired mechanical properties and corrosion resistance of the working conditions; often three stages of heat treatment is designed for precipitation hardening nickel-base superalloy. In general, the effective parameters of heat treatment cycles includes temperature, time, heating rate and the cooling rate. In this study, the effect of cooling rate from partial solution temperature (second stage of heat treatment) on the... 

Numerical simulations and large eddy simulations (LES) of turbulent flow downstream of diversion dam , pool-riffle bedform in different geometrical ratios (different lengths of riffle and pool) with flow Reynolds number of 3.0 E+04 to 3.3E+04, downstream of special case study "Mill and Moghan diversion dam" with Froude number of 0.5 are presented The calculations are performed using a computational fluid dynamics model, FLOW-3D, which solves the Navier-Stokes equations in three dimensions with finite volume method. Numerical simulations are validated by comparing the numerical results of time-averaged flow patterns downstream of pool-riffle sequence with that of the experimental... 

RF Receivers are one of the main components of telecommunication systems, which can be composed of many parts and circuits according to their working frequency and application.In this thesis, the design and simulation of an X-band Receiver in 0.15um GaAs technology has been discussed. The receiver chain, in the order of receiving the signal, includes the main blocks of limiter, attenuator, low noise amplifier and mixer. It also includes a number of filters. The attenuator has two digital bits and the receiving chain filters are implemented in such a way to provide more than 20dB attenuation in the frequency band of the image signal. In this research, the limiter is implemented with a... 

Liquide phase catalytic exchange (LPCE) between liquid water and hydrogen is an important reaction for separation of the hydrogen isotope from liquid water. One of the application of this reaction is heavy water production. This method is mainly used hydrophobic catalysts with Pt active metal. The use of hydrophobic catalyst is necessary, because liquid water in the LPCE reaction, resulted in block the catalyst pores and loss of catalyst activity. Design of experiment has been done by using of Design Expert 7.0.0 for determination of number of tests and optimization of Pt weight percent. Alumina and carbon (included graphene, single-walled and multi-walled carbon nanotube) supported 5% wt Pt... 

Heart failure is a chronic and significant disease that affects millions of people worldwide. Despite advances in medical technology and treatment options, heart failure remains a leading cause of death globally. This has led to a growing interest in developing new diagnostic tools and therapeutic strategies that can improve the control of this disease. One promising field is bioimpedance spectroscopy, which is a non-invasive method for measuring the electrical properties of biological tissues in the body. Monitoring the condition of fluid accumulation in the lungs of heart failure patients is effective in reducing the death rate caused by this disease. In this thesis, a portable device for...