Sharif Digital Repository

Given a divisible finite field extension K/F, the structure of Br(F), the Brauer group of F, is investigated. It is shown that, if F is indivisible, then Br(F) ≃ Z_2, which generalizes the Frobenius Theorem. As a consequence, when F is indivisible, the class of all finite dimensional non-commutative F-central division algebras D having radicable multiplicative groups is determined. In fact, it is proved that the following statements are equivalent: (1) D is radicable, (2) D contains a divisible subfield K/F, and (3) D is the ordinary quaternion division algebra and F(√-1) is divisible  

Since Iran is a part of Afro-Asian belt of deserts, 21 percent of its area belongs to desert lands. By the increasing number of dust storms in western adjacent countries dust particle concentration’s value has been critical. PM10 modeling and finding out dust origins can extremely help to manage methods by decision-makers to control dust from the origin. HYSPLIT modeling tool is benefited to get to this aim. In this study metropolises which hardly confront air pollution according to EPA statement were selected. HYSPLIT was calibrated and validated by comparing the results with measurement stations. According to the point that that particles were transported from western parts of Iran,... 

In the extension of his former developments of the theories of philosophy of mind and language, John Searle (1932- ) proceeded into the realm of social reality by his The Construction of Social Reality and Making the Social World, written in 1995 and 2010 respectively. With his naturalistic background, he placed his new theory on top of his former theories of mind and language already naturalized and fully worked out. As we will see, social reality comes with our three marvelous capacities, not coming together, to the extent we know, in animals other than us: collective intentionality, assignment of function, and language; all of them already being treated by Searle, in a naturalized manner,... 

In this work, the in-motion estimation of Euler angles of a strapdown inertial navigation system is studied using a speedometer, as an aided navigation sensor. First, the derivation of governing error equations has been done. Then, the most appropriate heuristic filters available in references have been chosen for this study. Among this filters, unscented particle filter, that has better performance and conditions for the real-time implementation, has been chosen. Then, an innovative solution for improving the performance of this filter is presented. The proposed filter uses particle swarm optimization to resample the particles. The proposed... 

Sohail Inayatullah is one of the most successful futurists of the last decade. His proposed method for futures studies, which is called Causal Layered Analysis (CLA), has attracted a lot of attention and has won futurists’ admiration. Although, Wendell Bell counts the study of epistemological foundations of futures studies as one of the major purposes in this field, unfortunately, no significant attempt has been made to clarify the epistemological foundation of CLA, up to this time. The primary purpose of this thesis is to relieve this weakness. Inayatullah calls his approach, in developing CLA, “critical”. On the other hand, Wendell Bell claims that Roy Bhaskar’s “critical realism” is an... 

In recent years, much attention has been paid to the preparation of nanoparticles as carriers for drug delivery. Nanoparticle carriers, by changing the pharmacokinetic properties of the drug, improve the function of the drug and reduce its side effects. In the manufacture of nanoparticles, various materials such as polymers, metal particles, lipids, etc. are used to transfer the drugs, which can produce a different shape and size of the particles depending on their production method. The purpose of this project is the synthesis of liposomal nanoparticles (as nano-carriers) to load an antibiotic (Eucalyptus oil) and study the release of the encapsulated drug in the simulated environment of... 

Nowadays, methods based on deep learning networks are the most effective artificial in­ telligence methods. Although they have achieved success in various fields (such as machine vision and object recognition), practical and experimental cases show the fragility of deep learning networks against perturbations and unwanted changes of the input pattern. All these perturbations must be in a way that the main class of the perturbed input pattern can be rec­ ognized by human, but the network makes a mistake in recognizing its correct class. This thesis seeks a more accurate evaluation by designing adversarial attacks such that the main class of the adversarial pattern is detectable by human... 

An accurate numerical methodology for capturing the field quantities a center lamellar inhomogeneity within the interface of two different phases of a bimaterial rectangular plate subjected to non-uniform tensile stress, in the context of reproducing kernel particle method (RKPM), is of particular interest. For this purpose the innovative numerical technique, so-called extended augmented corrected collocation method is introduced; this technique is an extension of the augmented corrected collocation method used for imposing continuity condition of the displacement at the interface. The robustness of this methodology is shown by solving problems of material discontinuities, namely plates... 

Linear position sensors are widely used in linear motion-control drives. In this thesis, the design, optimization, performance analysis, and prototyping of a linear variable reluctance, variable area resolver is discussed. To test the new design approach of the studied sensor, three-dimensional time-stepping finite element analysis (3-D TSFEA) is crucial. However, the 3D TSFEA is a very time-consuming method which leads to an inappropriate choice for co-using with optimization algorithms. Hence, an accurate analytical model based on a winding function (WF) method presented in favor of calculating the inductances, air-gap flux density, induced voltages precisely and yet is a very fast method,...