Sharif Digital Repository

The following thesis is concerned with the effect of channel feedback in tracking and stability of linear Gaussian systems over Additive White Gaussian Noise (AWGN) channel when the decoder is the Kalman filter and encoder is the innovation encoder. When the feedback channel is described by a noisy link or a random switch, it is shown that stability is not possible for unstable systems. But for stable systems, an innovation encoder, Kalman filter decoder and a certainly equivalent controller for tracking and stability are presented. When the feedback channel is described by a deterministic switch, for both stable and unstable systems, an innovation encoder, Kalman filter decoder and a... 

Seismic behavior of multi-story frames widely has been studied in recently. So that such studies can lead the earthquakes-resistance system to better performance. The dramatic growth of computer processing power make it possible that nonlinear dynamic analysis of structures with great precision could be done. One of the advantages of nonlinear analysis is achieve behavioral performance of structures during an earthquake. Knowledge of the performance, enables us to identify structural weaknesses result in devising to improve these. The aim of this study is to evaluate the seismic performance of reinforced concrete frames have been improved, using different techniques. The frames are designed... 

In this research, we will examine the emotions in the comments recorded about the tweets that have gone viral on the Twitter social media. We use Ekman's emotion classification model to classify emotions. Also, we choose the desired brands from the international brands of the fashion and clothing industry. These brands are divided into 2 luxury and non-luxury categories. Finally, we select 10 luxury brands and 9 non-luxury brands and extract all their tweets in a period of 6 months. Tweets that have been published more than a certain amount are considered as viral tweets, and using a machine learning model designed for this purpose, the emotions in the comments of users are analyzed and... 

The current design procedure known as Force-Based Design (FBD) method, generally, does not lead to uniform distribution of drift, hysteretic energy, and ductility demands (or structural damage) along the height of the moment frames under strong earthquakes and these performance parameters can be much higher and concentrate damage on one or more of the lower structural stories. This paper presents an iterative wave propagation (WP) based technique to calculate the seismic nonlinear response of multistory buildings as an extension of the layered soil media, founded on bedrock and subjected to vertically propagating shear waves, which leads to the introduction of a new Lateral Load Pattern... 

Worst case execution time (WCET) and energy consumption are two of the most important design constraints of real-time embedded systems and memory subsystem has a major impact on both of them. Therefore, many recent studies have tried to improve the memory subsystem of embedded systems by using emerging non-volatile memories instead of conventional memories such as SRAM and DRAM. Indeed, the low leakage power dissipation and improved density of emerging non-volatile memories, makes them prime candidates for replacing the conventional memories. However, accessing these memories imposes performance and energy overhead and using them as the code memory may increase the WCET.Furthermore, most... 

The problem of spacecraft attitude determination (AD) using thermal data is investigated. Given the Solar space environment, the key dominant mechanism of heat transfer will be radiation, in which the Sun and Earth are the major contributing heat sources that affect the satellite external surface temperatures. In this sense, the net heat fluxes (NHF) of a satellite surface that is insulated against any internal heat communication will only be related to these main radiating sources. In order to utilize the satellite temperature data for AD, a heat attitude model (HAM) that relates the satellite surfaces NHF to its attitude is developed using three orthogonal satellite surfaces. Assuming... 

The purpose of this research is to monitor the health of structures using the updated finite element model, in which digital images are used to optimize the numerical model. Structural Health Monitoring (SHM) is always an important and significant issue that has attracted the attention of many researchers in recent years. In general, some researches have been conducted in this field using physical sensors that provide discrete data to the system for analysis. Using cameras to monitor the structure makes it possible to extract continuous and integrated data from the structure using digital images, which is a significant advantage compared to physical sensors.In this research, a steel... 

Identifying the success factors of construction projects is one of the most important issues in project management. Lack of sufficient and comprehensive knowledge of project success factors makes it difficult to control, monitor and operate projects. Therefore, identifying the factors influencing the failure or success of projects according to the type of projects by managers, employers and executives can provide a good framework for evaluating and reviewing project outputs for them. Also, recognizing the success factors of projects can help to manage the appropriate allocation of resources throughout the life of the project. The result of this study can increase the existing knowledge about... 

To suppress stick-slip oscillations a controller is designed. However, because the lack of rotary speed at the surface, two approaches to implement this controller is considered: 1) Using an observer to estimate the rotary speed, 2) Using acoustic communication. To implement the second method, we confront several challenges including delay in the feedback loop and noise in communication system. In this thesis, a controller is designed based on prediction of the current rotary speed using its delayed value. It is shown that this system is less sensitive to uncertainty in system parameters compared to the controller based on observer. The performance of both systems in terms of settling... 

Because of the increasing use of distributed computing and edge computing patterns, broadcast communications are becoming increasingly important. This communication should be such that each node can deliver its information to all or part of the network nodes. The quantity of delay should be small enough to not disturb the rest of the control processes.
There are different topologies such as Mesh, Tree and Star networks, each of which has efficiencies according to the type of its media access control. In this thesis, a clustering architecture is proposed using the combination of Frequency Division Multiple Access with Carrier Sensing Multiple Access, and mathematical analysis is performed... 

One of the goals of the current research is to investigate natural structures to inhibit Ras proteins that belong to the family of guanosine triphosphatase proteins. For example, one of the common mutations is Kras mutations, which are seen exclusively in pancreatic ductal adenocarcinoma. Changes in Kras protein expression are observed in 30 percent of lung cancer cases. Kras mutations occur in 35-45 percent of colon cancers, leading to drug resistance. Our work method in this research is that we collect a dataset of natural compounds for the target protein. Then, the binding energies of these structures with the receptor protein are calculated through Autodoc Vina. After that, using deep... 

Environmental problems have been one of the considerable issues since the irreversible characteristics of nature and its effect on human life were recognized. Scientists have proposed a variety of solutions in order to overcome such problems. Green marketing can be regarded as one of the solutions in this area. Similar to most other issues, this concept has been noticed less in developing countries compared to developed countries. Therefore, researchers in this study conducted a comprehensive research on the concept of green marketing in Iran focusing on consumers’ behavior.
To achieve relevant results, two types of research were conducted: qualitative and quantitative. The results of... 

One of the main goals in large projects with multiple contractors is to reduce costs in various processes. The complexity of a large project, which is mainly due to the complexity of activities and the existence of interference between different phases and the lack of transparency of activities, can be added to the multiplicity of contractors and the difficulty of proper interface management.As regards that large projects with a large scope of work, have to use several contractors and this issue has a direct impact on increasing project costs, large project management becomes a major challenge that the application of appropriate knowledge, improving processes and skills and tools can play a... 

Achieving various data rates over a wide range of applications and in a multiple-access scenario should be done under certain power and bandwidth constraints. Emerging UWB communications has opened a novel perspective against different wireless network challenges, especially overwhelming data rates. In the research field, we begin our thesis with exposition of UWB, narrowband interference and spread time codes. We elaborate on the properties of spread time codes through frequency domain analysis of a reusable multiple-access scheme. Evaluating the variance of ISI, MAI and RUI, we demonstrate the spread time codes behave in an optimum manner, i.e., the most RUI resistibility, along with all... 

By direct and alternating electric field applied to thin film of liquid suspended in the air we can spin out and control it. Rotation pattern depends on the geometry of the electrodes and the applied magnetic field. This is called a rotating liquid film (Liquid Film Motor). To determine the cause of rotation, different models have been proposed. In this project we have tried to check the accuracy of any of the models. Using particle velocimetry using the photo, we calculate the velocity pattern. Then, using the Navier-Stokes equation calculate the acceleration and viscosity from the velocity. Then, for a special arrangement using a finite diffrent method, electric potential and the electric...