Sharif Digital Repository

Flame Response to acoustic excitation which plays an important role in combustion chamber stability state may be found through numerical simulation. A finite volume code of higher order accuracy developed for compressible flows was adopted. Species equations along with a single-step irreversible reaction model were added to this non-reacting program. Changes were also made to the energy equation. Premixed methane/air flame in tubes was studied and the same problem was solved with FLUENT software. It was found that whether the Lewis number is considered constant or temperature dependent has a strong effect on flame structure and shape and that using mean values for gas properties yields out... 

One of the different methods of heat transfer, is pool boiling process. In this method, the operating fluid starts to boil on a hot surface whose temperature is more than boiling point of the fluid. Based on difference between between surface temperature and fluid boiling point, amount of heat flux from hot surface to fluid and fluid behavior will be different. In recent years, many researchers have tried to improve the amount of heat transfer in the boiling process by using various methods such as nanoparticle addition or using magnetic field.Latent heat is thermal energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process, usually a first-order... 

Online searching for product information or buying some certain goods online has become increasingly popular during the last few years. Despite this fact there is still little empirical evidence about the relationship between in-store shopping and e-shopping. The substitution effect between these two types of shopping can have significant outcomes in urban transportation. Hence Analyzing different aspects of this new phenomenon and using its potential substitution effect on in-store shopping to decrease the amount of mobility in transportation system can be an attractive subject for urban transportation planners. The main purpose of this study is to reveal the relationship between the... 

Renewable energies and their various types have been recognized as sustainable solutions to address the challenges arising from increasing energy consumption and environmental issues. The use of wind energy as one of the renewable energy sources has particular advantages, considering it as one of the most sustainable energy sources. One of the key factors in wind turbine development is the diversity and multiplicity in their structural designs. Therefore, the design of wind turbine structures with characteristics such as suitable strength, high energy efficiency, optimal cost, and high reliability is of great importance. By employing various sciences such as vibrations and optimization in... 

Cardiovascular diseases are the leading cause of death globally so early diagnosis of them is important. Many researchers focused on this field. First signs of cardiac diseases appear in the electrocardiogram signal. This signal represents the electrical activity of the heart so it’s primarily used for the detection and classification of cardiac arrhythmias. Permanent monitoring of this signal is not possible for specialists so we should do this by means of Artificial Intelligence. In this thesis, we use recurrent neural networks to classify electrocardiogram’s arrhythmias. This deep learning method, use two sources of data to learn from. The first part of data is global for everyone and the... 

Among different natural disasters, earthquake has always been known as one of the most effective ones on human lives, and this is only because we still cannot predict the exact time and place of its happening. So, giving special attention to the methods which can omit or minimize the damages of this natural event is needed for controlling the loss in the event of an earthquake. On the other hand schools are known as places which are full of people from younger ages for at least half of each day, and they are considered to be not well educated about how to react in an earthquake in comparison to older people and also considered vulnerable at the time of this natural event. According to what... 

Nowadays, Multi-Object Tracking (MOT) plays a crucial role in various computer vision applications such as autonomous vehicles, surveillance, and robotics. Traditional MOT methods often struggle with challenges such as high errors when dealing with complex scenarios involving occlusion, scale variations, and object interactions. Recent advancements in deep learning, particularly Convolutional Neural Networks (CNNs) and Transformer models, have demonstrated significant capabilities in addressing these challenges. This thesis presents a study on the use of deep learning techniques, specifically CNNs and Transformer models, for solving the problem of Multi-Object Tracking. It begins by... 

Procedural Content Generation (PCG) is a critical challenge in video game design, aimed at automating the creation of complex maps and levels. This thesis presents a novel deep learning-based approach for PCG that integrates transformer architectures with reinforcement learning techniques. Building on previous works, this research seeks to enhance the quality, diversity, and success rate of generated playable levels. The proposed method utilizes transformer architectures to model sequences of actions, states, and rewards, predicting optimal game content based on past trajectories. Offline datasets, generated by semi-expert agents trained in the PCGRL framework, serve as the foundation for... 

Carbon-based thin films possess low friction coefficient, low surface roughness, chemical inertness and outstanding biocompatibility. In the present work, TiO2 nanoparticles were covered by a thin film of pyrolytic carbon (PyC) to provide a core-shell morphology. The PyC film was deposited by dehydrogenation of methane in a fluidized bed chemical vapour deposition (FBCVD) reactor at 1100 °C. The prepared specimens were characterized by various analytical methods including XRD, SEM, TEM, AFM, TGA and contact angle measurement techniques. Biocompatibility profiles of the resulting materials were evaluated using MTT and cell cycle assay. The results showed that the thin carbon film strongly... 

Data envelopment Analysis is a non parametric technique which estimates the efficiency of a decision making unit in compare with others. In correspondent literature this unit’s Inputs and outputs are often assumed to be deterministic, but in recent years different approaches which viewing the data as non deterministic are presented. In this study we propose an algorithm for determining the stability region of a DMU while we assume other DMUs’ data are fixed. This algorithm is based on changing the reference set of the under investigation DMU. In fact applying these changes make the DMU move toward other DMUs’ efficient frontiers and by using this fact it is possible to determine the... 

The Quadriceps Muscle as one of the major muscles of the human body plays a key role in knee function. Strengthening of this muscle is recommanded to prevent knee pain and even cure some diseases. Many believe that by strengthening the medial part with respect to the lateral part of the quadriceps muscles, patellofemoral pain syndrome can be prevented or treated. In this regard, a muscle strengthening system, based on magneticorheological brake is designed which provides isometric, isotonic and isokinetic exercise of knee joint and also enables the selective muscle strengthening. Beforehand a musculoskeletal model of lower extremity is developed in OpenSim software, capable to estimate force... 

Truth and Method is one of the two or three most important works of this century on the philosophy of humanistic studies. The book is powerful, exciting, but undeniably difficult. Published when Gadamer was sixty, it gathers the ripe fruit of a lifetime's reading, teaching, and thinking. Because it is immersed in German philosophy and scholarship, the book is even more challenging for an American reader. An emerging body of commentary in English as well as the many shorter essays Gadamer has, happily, lived to write and which are increasingly available in translation provide additional means of access to his thought. Truth and Method, however, remains his magnum opus, the comprehensive and... 

The theory of resonant wave interaction has found considerable applications in meteorology, oceanography and limnology. It is known that the mechanism serves as an effective means of energy transfer in the atmosphere, oceans and lakes. In this project, the three-dimensional resonant interaction of a surface wave with two pairs of interfacial waves in a stratified fluid is studied theoretically. Witham’s variational method is formulated in order to apply to weak resonant interaction among waves whose amplitudes and phase angles vary slowly with position and time. The method is applied to a surface-interfacial wave interaction in a horizontally infinite two layer fluid. Combination of two... 

Using Variational Method, two important hydrodynamic phenomena, “internal gravity waves” and “gravity currents”, are modelled theoretically in this research. Variational method as a robust technique for modelling complicated problems related to fluid mechanics gives us the ability of finding closed-form formula for predicting the behavior of the flow in an ideal fluid system. In the first part of this research, focusing on the nonlinear resonant interaction between surface and internal waves, we model the evolution of interfacial waves on the interface of a two-layer fluid system. This phenomenon play an important role in the mixture of the fluid and cascade of energy in the environment.... 

The objective of OCR systems is to retrieve machine-encoded text from a raster image. Despite the abundance of powerful OCR algorithms for English, there are not many for Farsi. Our proposed algorithm is comprised of pre-processing, line detection, sub-word detection and segmentation, feature extraction and classification. Furthermore, hardware implementation and acceleration of this system on a GPGPU is presented. This algorithm was tested on 5 fonts including Titr, Lotus,Yekan, Koodak and Nazanin and an average accuracy above 90% was achieved