Sharif Digital Repository

Thorough investigation of the Cloud-RAN (C-RAN) architecture has recently shown that CRAN can bring advanced cooperated and coordinated processing capabilities as well as the multiplexing gains toward future radio access networks. The baseband processing of each base station instance can now be flexibly split into smaller functional components, that can be placed either at remote radio units (RRUs) or baseband units (BBUs), depending on the available resources. In this project, we investigate recent implemented methods in C-RAN. also, we propose, develop and implement new architectural frameworks for C-RAN that can support both a flexible functional split and a new functional splitting known... 

In this research, we have presented a method to delay the propagation of fault current in high voltage power supplies. Common protection methods usually protect the load and do not protect the power supply itself well. In this research, our goal was to propose a method to prevent the short circuit fault current from reaching the power supply elements. At first, the available methods to limit the fault current and protect the high voltage power sources were studied and investigated. Then, using the transmission line theory, a ladder filter was designed as an alternative to the normal filter at the output of the power supply. In the next step, using software simulation, the performance of the... 

A Tesla charged PFL Bipolar pulsed power generator has been successfully designed and simulated. The compact Tesla transformer that it employs has successfully charged capacitive loads to peak voltages up to 0.6 MV . The Tesla–driven PFL generator is capable of producing a voltage impulse approaching .3 MV with generating a peak electrical power of up to 1.8 GW for 5 ns when connected to a matched resistive load. Potentially for medical application, a bipolar former has been designed and successfully simulated as an extension to the system and to enable the generation of a sinusoid-like voltage impulse with a peak-to-peak value reaching 600 kV and having a frequency bandwidth beyond 1 GHz.... 

With the expansion of the use of electric energy, the importance of sustainable supply of this energy has been revealed. The task of supplying this energy is with power systems, therefore, for a stable supply of electrical energy, it is necessary to continuously monitor the systems. Power systems are composed of various destructible components such as cables. There are various methods and tests for maintaining and monitoring power cables. One of the daily maintenance methods of alternating current cables is called very low frequency testing. The main advantage of this test is the small and portable nature of the test equipment. In this thesis, the design of a very low frequency alternating... 

Gene regulatory modeling in different species is one of the main aims of Bioinformatics. Regarding the limitations of the data available and the perspectives which should be taken into account for modeling such networks, proposed methods up to now have not yet been successful in yielding a comprehensive model. In one of the recent researches, the Gene regulation process is considered as a nonlinear dynamic stochastic process and described by state space equations. Afterwards, in order for the unknown parameters to be estimated, Extended Kalman Filtering is used. In this thesis, first of all, Gene complexes are taken into consideration instead of genes and afterwards, Extended Kalman... 

In the last few decades, the consumption of fossil fuels and its increasing worldwide price on one hand, and the severity of global warming on the other hand have led researchers and engineers to invent and expand new cooling technologies. Cooling has the largest portion of energy consumption of households during the hot season of a year. In addition to high energy consumption, the common cooling systems utilize gases which are harmful for environment. Thermoacoustics is a new and recent technology which has arised from combination of acoustics and thermodynamics. In Iran, research in this new field was pioneered by Ghorbanian in Department of Aerospace Engineering at Sharif University of... 

Sulfur compounds are largely an impurity in fossil fuels such as natural gas, crude oil and coal. In natural gas, the main sulfur compounds are hydrogen sulfide (H2S), carbonyl sulfide (COS),and C1-C3 mercaptans.Commercial methods for removing these compounds require the introduction of additional reactive substances (O2, H2, Olefins, NaOH, etc.), which often results in the production of other pollutants. Microfluid is a branch of science and technology that involves studying the behavior of fluid, the use of fluid and the manufacture of equipment or systems that are carried out in micro-channels.The dimensions of these canals are about ten to several hundred micrometers, and high of... 

Cloud control systems have garnered significant attention due to the many advantages of cloud computing, such as the ability to store and process large amounts of data efficiently. However, transferring data over public networks introduces several challenges for control systems. One major concern is the system's vulnerability to eavesdropping and security threats. Additionally, the computational demands of cloud-based controllers can result in increased system delays. This thesis addresses these challenges by integrating encryption methods with control theory. It focuses on mitigating the computational overhead introduced by encrypted networks and proposes two innovative solutions to tackle... 

Nowadays, software systems face many challenges that relate to their maintenance, scalability, and development. To address these challenges, many large software systems have moved away from monolithic architecture and adopted a microservicesbased architecture. However, microservices-based systems face security challenges due to their distributed nature, complex dependencies, and diverse implementation technologies. This study specifically examines architecture-based threats, which fall under the program logic-based category. Previous research has required access to the server-side architecture to recover the architecture of the system, but this study proposes a method for recovering the... 

In the present thesis, first of all we consider a particular class of fractional order plants which have uncertainty in their time constant.In order to make the closed loop system robust against variations of the aforementioned parameter, a robust fractional order controller will be designed and the corresponding tuning rule will be expressed. By using the proposed controller, phase margin of the system will be preserved on a desired value for any value of the uncertain parameter and also gain crossover frequency of the system, in the nominal case, will be adjustable.Also another class of fractional order system will be considered. For these systems, the problem is the same as the former... 

Distal humerus fractures commonly take place in adults with low bone mineral density causing major technical challenges upon orthopedic surgeons. Persian fixation method was introduced as a novel technique to stabilize small fragments in comminuted distal humerus fractures using a set of K-wires and reconstruction plate. The objective of the present study is to measure the stiffness and stability of this technique and analyze the effect of influential parameters with numerical simulation and biomechanical testing on a cadaveric specimen. Furthermore, we were able to propose new method to model plastic deformation of implants in surgery.Validation of the finite element (FE) model was... 

In the oil industry, after drilling an oil well and laying pipes, it is time for the hydraulic fracturing process. In the process of hydraulic fracturing, a fracture must be created in the casing pipe of the well. The reason for this is that the oil from the existing reservoir enters the well so that it can be extracted. The end of the well must be blocked to cause a fracture in the well body. The reason is that after creating a fracture in the casing pipe, proppant particles are pumped together with water inside the well to keep it open. For the proppant particles to be placed inside the cracks, it is necessary to create pressure in the fracture area. To create pressure in the fracture area... 

Predicting the Amino Acids that have a catalytic effect in the enzymes, is a big step in appointing the activity of the enzymes and classifying them. This is a very challenging job, because an Amino Acid can appear in a variety of active sites.The biological activity of a protein usually depends on the existence of a small number of Amino Acids. Detecting these Amino Acids from the sequence of Amino Acids has many applications. Usually, the Amino Acids that are preserved are known as the Amino Acids that build up the active site, but the algorithms for finding the preserved Amino Acids are much more complex. There are a lot of algorithms for predicting the active sites of Amino Acids, but... 

The present case study investigates the effect of applying a humanoid robot as a teacher- assistant to teach a foreign language (English in this case) to Iranian children with autism. Two groups of three male high-functioning autistic students (6-10 years old) with little or no background in English participated in the current study. The humanoid robot NAO made by Aldebaran Robotics was used as a teacher assistant to teach English to the Robot Assisted Language Learning (RALL) group. The non-RALL group received the same lessons simply without the presence of the robot in teaching sessions. However, the non-RALL group also had the chance to interact with the robot through some robotic games... 

A special steel beam-to-column connection, named Khor-jini, is commonly used for steel framing system in Iran. In this system, two continuous beams are passed next to the columns and are connected to the column side using seated brackets.This type of connection has been common in Iran from the late past. Unfortunately, the seismic behavior of Khorjini frames had not been sufficiently studied prior to Manjil Earthquake of 1990. Due to very large damages which occurred in steel structures especially in connections during the said earthquake, the seismic behavior of this type of connection was studied and some of its weak points were recognized.In this study non-linear...