Sharif Digital Repository

In this document, the cooperative estimation of states between two interceptors and one target is expressed in order to evaluate the effect of information sharing in different situations on the estimation performance. Due to the importance of the proper estimation of the target acceleration in advanced navigation rules, the main focus of the document is on a more precise estimation of the absolute states of the target. For this purpose, a filter based on the extended Kalman filter was used as an estimator, and to evaluate the promotion of the estimation performance, the combination of measured data was used in two different ways. Matlab Simulink is the simulation software used. The dynamics... 

In recent years the rapid rise of polymer consumption especially in the form of packaging materials became a real menace for the environment. Polyolefin are some of the most dominant packaging materials and responsible by part of the problems in the disposal of one-trip packaging. One of the possible ways of solving this problem is the introduction of additives increasing their susceptibility to environmental degradation into non-biodegradable polymers. One such additive is starch- the natural, cheap, and easily biodegradable polymer. Starch was already used as a filler or as a blend with polyolefin. Addition of dry starch granules to polyolefin follows the general trend of filler effects on... 

Isogeometric Analysis method is a newly introduced method for the analysis of problems governed by partial differential equations.The major difference between classic finite element method and isogeometric method is that FEA uses piecewise polynomial shape functions for analysis while the Non-Uniform Rational B-Splines (NURBS) functions are applied as basis function in isogeometric method. To model strong discontinuities like cracks in classical finite element method , very fine mesh near the crack tip must be used. Application of eXtended Finite Element Method (X-FEM) avoid making very fine mesh near crack tip which is a time consuming task. In the extended finite element method , a... 

The three-phase Dual Active Bridge DC-DC converter, by virtue of its various advantages, has been widely used in numerous industrial and sensitive applications. However, this converter includes a large number of power switching devices, which are the most fragile components in Power Electronics, and therefore, can pose a threat to appropriateness of the converter for such applications. Accordingly, introducing a fault-tolerant scheme for this converter is necessary, in order to meet the demands of high reliability and service continuity in aforementioned applications. In this thesis, firstly, the converter is studied during normal operation as well as under switch open-circuit fault, and the... 

There are many linear and nonlinear programming problems with uncertain parameters and variables. These types of linear and nonlinear models are called fuzzy linear and nonlinear programming problems. Solving such problems is important, due to applications and variety of these models. Here, we first review various types of fuzzy linear programming problems based on the models or the solution methods. Next, we revise a method due to Kerre to compare two unipolar LR fuzzy numbers and present some new results on the comparison of LR fuzzy numbers. Then, we solve linear programming problems with unipolar fuzzy numbers by our proposed time varient particle swarm optimization (TV-PSO) algorithm.... 

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... 

Cloud computing is a way to increase capacity or add capabilities dynamically without investing in new infrastructure. The purpose of this project is the use of specialized algorithms for efficient energy management for cloud computing environments.One of the issues that is very important with respect to cloud computing is considering lifetime of servers or physical machines. Servers are some of the most important and critical elements of cloud computing. Server costseffect on the costs of the entire cloud computing system and the interference of serverseffects on entire system. Lifetime of each sever is dependent on a few factors, the most important of which is the number of switching... 

In the present research, model-based reasoning is introduced and explained based on Giere’s explanation of model. In other word, this research could be regarded as a reconstruction of model in Giere’s books and papers due to prpose a clear explanation of model-based reasoning. In the second chapter, after the introduction, the concept of model in Giere’s distinguished book, “Explainnig Science: A Cognitive Approach” (1988) is introduced and analyzed. In the second chapter, however, the concept of model in Giere’s recent works is traced. “An agent-based account of model” and “focusing on functionality rather than ontology” could be explained as the two important differences between his... 

The need for planning for the management and recovery of flare gases is an important issue in the energy sector of the country. On a day, about 46 million cubic meters of gas in Iran is burning in the torch, which in addition to the destruction of non-renewable energies, contributes to environmental pollution and emissions of greenhouse gases. Gas burning is one of the few pollutant activities that is due to short-term economic revenues, system design weaknesses, and lack of management in the operation process, with no service provided or value added. Iran is ranked third in the world according to satellite data among the countries that are burning flares. Accordingly, by burning 17/7...