Sharif Digital Repository

One of the most common and effective ways to treat end-stage renal disease is the use of kidney exchange techniques. However, the main problem with this treatment is the presence of many barriers to allocating kidney pairs to each other, which reduces the success of kidney transplants. Among different types of kidney transplantation methods, the present study utilizes kidney transplantation cycles to develop the allocation of unmatched pairs in kidney transplantation using a data-driven optimization technique. In this study, HLA patients were considered as simulated and also a two-objective model in the kidney exchange network was designed to maximize the probability of kidney... 

The integration of radar and communication functionalities into a unified Joint Radar-Communication (JRC) system offers enhanced spectral efficiency and reduced hardware complexity. Recognized as a key enabler for next-generation wireless networks, JRC systems require a careful balance between radar and communication demands, where waveform design plays a pivotal role in achieving this equilibrium. Although waveform design has been extensively studied separately in radar and communication domains, the requirements of modern networks necessitate a unified approach that simultaneously addresses the needs of both systems. This thesis advances waveform design methodologies for JRC systems,... 

The topic of knowledge creation and knowledge management is one of the most leading issues in management studies in today’s world’s organizations.Knowledge creation is known as the first and the most basic step in knowledge management and it can provide the prefaces of developing a management work frame in an organization.In this thesis after reviewing the goals and purpose of the project under consideration, the literature of knowledge management is reviewed and the most important models of knowledge management are selected and analyzed.Also, the organization selected as a case study is fully studied and the necessary information is gathered on the basis of proposed indexes at two public... 

The thesis addresses the buckling and post-buckling analysis of an elastic conical shell under non-uniform axial loading using finite element method. Non-uniform axial load is applied to one end of the truncated cone in the form of two equal-length loaded zones, diametrically opposite to each other. Material used in this thesis is isotropic with linear elasticity. The results are presented for different boundary condition. The results show that the buckling strength obtained by nonlinear analysis may be upto 40% less than the buckling strength obtained by linear analysis. The effects of boundary conditions and geometry on the results has been investigated  

The design of an indicator for "quality rate measurement" has been done in many countries around the world, and the quality rate, like other economic indicators, is subject to public judgment. Prerequisite for the formation of this index is the existence of a "comprehensive system" for quality management in the country, in which the duties and powers of various institutions in the issue of quality are specified and responsible for each process. With this excellent system, quality management is done in an integrated manner and quality can be managed efficiently by providing indicators.Quality assessment, in addition to hearing the customer's voice, requires other aspects, including examining... 

Predicting the trend of stock prices is always one of the concerns that stock market analysts and investors face with, which plays a critical role in maximizing the profit from investing in stocks. Past stock price charts, raw material prices, the value of the company's assets, the impact of global markets, the company's products, the organization's development plans, and the same other factors influencing the stock price. News reports are an important source of information for people. Recently, a lot of research has been done to examine the impact of news on stock price trends. This research has two research phases. In the first phase, a text mining method is presented which is using... 

In recent years, investment in financial markets has seen exponential growth in the number of investors and the capital they have invested. Investors enter these markets with the goal of maximizing their transaction profits. Therefore, they are looking for a way to predict the future of the market. On the other hand, numerous factors influence stock prices and market trends, making the prediction of these markets a highly complex task. In recent years, with the remarkable advancement of artificial intelligence, analysts’ ability to predict stock trends has greatly improved. In this research, we attempt to predict stock trends using financial market concepts and machine learning models. To... 

In this dissertation, the application of frequency and space diversities in radar target parameter estimation are investigated. On this basis, multi-frequency signal is used to improve the range resolution, array structure is used to increase the angle estimation accuracy and the merger of the multi-frequency signal and array structure are used to increase the maximum number of targets that can be uniquely identified.Considering the desirable properties of multi-frequency signals such as high bandwidth efficiency, high range resolution achievement without chip length decrease and …, there has been increased interest in the vast area of research on the design of such signals that has... 

Target recognition techniques based on micro Doppler phenomenon are popular because they are applicable even on low resolution radars, in contrast to other techniques such as High Resolution Range Profile (HRRP) which need high resolution in range or angle. Usually, main purpose of such techniques is generating robust features against target initial state, velocity, aspect angle, etc. rather than features which exactly identify a target. Main approaches in the literature are based on time-frequency transforms (TFT) such as spectrogram in order to generate features to classify targets, but in this thesis, we propose a totally different method using Recurrence Plot for generating features... 

In this research with Finite Element Methods in ABAQUS, numerical modeling has done in three-dimensions, which can be used to determine the effect of different factors on the surface settlement. Also, various factors such as geotechnical conditions, tunnel diameter,tunnel depth, the impact of the thickness of the segments and the amount of eccentricity of the structure relative to the longitudinal axis of the tunnel considered in this study. Face Pressure Supports, and Grout Injection Pressures are taken into account, too.Tunnel drilling causes a change in the displacement area and creates a changing zone around the tunnel. In this regard, not only adjacent buildings will be affected by... 

In the present work, the dynamic charactristics of an oil lubricated journal bearing are identified by experimental modal test. First other similar articles were studied. Then according to requrements and specifications of the bearing, a test bed is designed and constracted by existing technologies to perform tests and to collect required data. The test bed consists of several parts, including rotary shaft, stator, oil supply pack, dynamic force shaker and various sensors, which are constructed and assembled with very precise tolerances. In order to identify the dynamic coefficients of the bearing, the test process was performed using dynamic and static forces and collecting required data.... 

A significant portion of the substances used in the chemical industry are toxic and hazardous, posing major safety hazards. In this regard, studies on the flammability limits of flammable materials are important and necessary. Flammability limits are the range of fuel-oxidant mixtures that can lead to flame propagation. This project examines the flammability limits of different fuels. In this study, a set of fuels have been selected as the fuel world, and to select these compounds, their molecular structure as well as thermodynamic properties such as standard enthalpy of formation and standard enthalpy of combustion have been considered. It has been shown that by redefining the fuel world,... 

Proton precession magnetometers are one of the most sensitive scalar magnetic sensors. Their function is based on Zeeman effect and also nuclear magnetic resonance phenomena. In this project we have designed and implemented needed coils, swithching and signal detection circuits. Because of extremely high sensitivity of this sensor to induced noises and also gradient of earth’s magnetic fileld, detection of precession signal needs design of low noise electronic circuits with special EMC considerations. The implemented system in this project contains different blocks, such as switching circuit and its related control unit, amplifier, filter and frequency meter. Using this system, the obtained... 

Effective field theory is a practical method for model building and explaining experimental/observational data. These theories are constructed based on knowing low energy degrees of freedom and symmetries (accidental or fundamental). By construction, these theories are applicable up to a cut-off scale and their predictions beyond that are not reliable. For applications to higher energies a UV completion is needed through which modifications are applied or new heavy degrees of freedom are introduced. In order to complete a theory in a Wilsonian approach, scattering amplitudes must satisfy some constraints. These constraints are derived from basic assumptions like Lorentz invariance,... 

Numerous structures which are involved in seismic soil-pile-structure interaction have been destroyed. Considering complexities which exist in soil-pile interaction problems and lack of precise methods without imperfect bases, it is necessary to use numerical methods for analyzing soil-pile interaction problems. In this research, three-dimensional modeling and studying the effect of changing soil and pile parameters on the behavior of pile under earthquake loading is performed using finite difference software, FLAC3D. The soil in this model has a softening behavior. Real earthquake spectrum has been applied into the model as the acceleration time history at the bedrock level. The results of... 

Suction caisson is a relatively new technology which was introduced about 30 years ago for the first time and after several investigations, was found its position in the oil industry and construction of anchorages, during previous decade. So nowadays, it is the most effective and economical choice as the mooring of offshore structures in comparison with the other foundations. Suction caisson is a hollow cylinder with an open bottom and a closed top. After placement on the seafloor, the caisson first penetrates into the soil by its self weight and then inserts into the ground by pumping water out of it. Although many researchers have attempted to understand the behavior of suction caissons... 

Modern communication and space systems such as satellite communication devices, radars, SAR and radio astronomy interferometers are realized with large antenna arrays since this kind of radiating systems are able to generate radiation patterns with high directivity and resolution. In such a framework, conventional arrays with uniform inter-element spacing could be not satisfactory in terms of costs and dimensions. An interesting alternative is to reduce the array elements obtaining the so called ‘ thinned arrays’. Large thinned arrays have been exploited because of their advantages in terms of weight,consumption, hardware complexity, and cost over the... 

Multi-period Value-at-Risk (VaR) forecasting is important for risk management. Financial institutions especially commercial banks according to Basel Committee regulations for capital adequacy in “Internal Approach”, should forecast their VaR for multi-period horizons (longer than one day). The most conventional approach for forecasting multi-period VaR is scaling one-day forecasted VaR that is called “square root of time rule”; therefore most works in this area have been focused on forecasting one-day VaR. In this study, we review performance of a wide range of different methods in forecasting multi-period VaR. The results of our study show that historical simulation performs weakly in... 

The current global economy challenges and the importance of maintaining a sustainable development strategy has increasingly bolded the importance of construction productivity measures. This research describes the results of a running research that is to find the most critical factors affecting the productivity of high rise concrete building projects in developing countries. To achieve that, we have conducted Delphi method in two phases. In the first phase we had a brainstorming program with construction experts from owner organizations, construction contractors and designing engineers to identify factors that have influenced productivity in recent concrete building construction projects.50... 

A large number of structures subjected to the seismic loading have been damaged or have experienced failure in different parts such as the pile structure or even in the entire structure due to unanticipated effects of the soil-pile-structure interaction.The complexity of problems regarding the soil-pile-structure interaction is an influencing factor in prediction of the behavior of structure during the earthquakes. In this study, the effect of the interaction on the dynamic response of bridges was investigated using the finite element software ABAQUS. The primary purpose of this study, as previously described, is to study the effects of the soil-structure interaction on a bridge located on a...