Sharif Digital Repository

One of the most important pillars of independence in the space programs of any country is to have the capability of tracking and orbit determination of its own satellites. Hence, in this project, based on the practical approach, a radio-tracking system has been designed domestically for Iran. In this one-way radio-tracking system, the pseudo-noise code, which in fact has the role of spreading frequency spectrum in the satellite digital communications, is employed as the periodic ranging signal. Furthermore, the Doppler effect on the carrier-wave frequency provides the range rate of the satellite. Thus, it has been shown that from the satellite waves, which are emitted omnidirectionally for... 

A simple, fast and sensitive method based on microextraction in packed syringe (MEPS), a new format of solid-phase extraction (SPE), as a sample preparation technique in off-line combination with gas chromatography-mass spectrometry (GC-MS) was developed. Polyaniline (PANI) nanowire network was synthesized and used as sorbent of MEPS for the multiresidue determination of selected analytes from triazine, organochlrorine and organophosphorous pesticides in aqueous samples. The PANI nanowires network was prepared using soft template technique and its characterization was studied by scanning electron microscopy (SEM). The use of micelles in this methodology has an important role in the shape of... 

There are many papers in which some graphs are assigned to algebraic structures such as rings groupsThe concept of regular graph related to a ring was rst investigated by DF Anderson and A Badawi in Assume that R is a commutative ring and Z??R denotes the set of zerodivisors of R and Reg??R R n Z??R The regular graph of R which is denoted by Reg????R is a graph whose vertex set is Reg??R and two vertices x and y are adjacent if and only if x y ?? Z??R This can be generalized to a non commutative ring For the vertex set we consider the set of left ??right zerodivisors and join two elements if their sum is a left ??right zerodivisor Let R be the ring of n n matrices over a eld F with... 

In this research a model is proposed which determines flight frequency and aircraft routing for an airline network. It is supposed that origin-destination demand, costs, number of aircrafts in the fleet and their capacity, aircraft maximum daily utilization hours and origin-destination fares are given. The model attempts to maximize airline profit and determines flight frequencies, number of passengers carried between two cities and number of passengers who travel with an indirect flight, considering fleet constraints and an operational aircraft routing.The model is tested with a hypothetical numerical example. The results indicate that the model uses maximum aircraft capacity and daily... 

The simplest definition of Total Factor Productivity is the rate of converting inputs to outputs. In other words, with fixed inputs and a raise in the Total Factor Productivity, more output can be achieved. In this study, we review the existing methods for calculating this variable and its determining factors. On the basis of Diewert’s criteria, Fisher index is known to be the most appropriate indicator to calculate production, price and productivity indices. Fisher index is obtained by dividing the index of output to input in which in addition to values of output and input, price data are also used. Between prices and values used in this calculation only price series for wages are not... 

In this research, an amperometric inhibition biosensor for the detection of cyanide has been fabricated by immobilization of the horseradish peroxidase (HRP) on the surface of glassy carbone electrode (GCE). Chitosan/acrylamide was applied for immobilization of HRP on the working electrode. All electrochemical measurement were carried out with three electrode: Ag/AgCl electrode as reference electrode, GCE as working electrode and platinium electrode as counter electrode which immersed in phosphate buffer solution. The amperometric measurement was done at an applied potential of -100 mV versus Ag/AgCl with a scan rate of 100 mV in the presence of hydroquinone as electron mediator and... 

Rapid growth of space traffic and small satellite systems for current and future space missions have generated new enhanced performance requirements for navigation subsystem. As such, the navigation subsystem is considered as a vital part of all active satellite systems that effectively influences their successful missions. In this regard, the present work is dedicated on the subject of autonomous satellite navigation utilizing nonlinear filters, for which some laboratory experimentations have also been implemented. Generally, advanced orbit and attitude estimation algorithms can effectively compensate for the effect of low cost hardware and sensor packs utilized in microsatellites. In... 

The discovery of Iron-based superconductors with maximum transition temperature of 56 Kelvin and High critical magnetic field of the order of 50T at temperature 20K has created evolution in different fields of superconductivity including practical issues. BaFe2As2 family is one of the most important compounds of Iron-based superconductors and with different doping elements for instanse elements of the first column like Potassium inters superconducting state with critical temperature of 36K.
The purpose of this thesis is to localize the technology of making this compound in Iran which no project has been done in this field in the country before. In this thesis manufacturing, Optimization... 

In this dissertation, the thesis of Duhem-Quine holism will be intoduced and its similarity and dissimilarity in epistemolical webs of Duhem and Quine will be enumerated and criticisms that is taken to this thesis will be examined. In chapter 1 and 2, the fundamental characteristics of Duhem and Quine viewpoints will be introduced in sequence. This chapter is introduction to more accurate understanding of holism each of them and better Comparison together. In chapter 3, we will introduce their holism and we’ll see what the results of their holism in falsification and confirmation of different Hypotheses are. In chapter 4, we will discuss about discrepancy between their viewpoints and we... 

An autonomous method for attitude and position determination of a satellite without using data from ground stations and also without the need for human interference is proposed using the image that the satellite has taken at each moment. The proposed method is based on recognition of stable features in the image and using them in order to match the satellite image with a source image from the Earth and the latitude and longitude of the features become known.SIFT and SURF algorithms have been examined. Using the perspective equation and camera coordinate system, a model has been developed that relates the coordinates of a point in the image with its equivalent coordinates in the real world.... 

By using of raw measurements of GPS receivers including carrier phase and Doppler frequency we can estimate attitude parameters of a platform on which the receivers are installed in a proper orientation. In this research attitude parameters are estimated based on quaternions. To this end a discrete Kalman filter was designed to predict the attitude parameters by using of carrier phase double difference measurements and then update the predicted parameters by using of Doppler frequency double difference measurements. Doppler frequency measurements were used to estimate the quaternion rates which are used in update step of Kalman filter algorithm. A robust algorithm for carrier phase ambiguity... 

The present study aimed to investigate the application of self-leadership strategy by participants in a training course of employment interview through the role playing method to face the relevant challenges. Solving or regulation of the challenges in a training course can result in participants’ learning improvement. This course was taken place as a part of the Human Resource Management Course in 2017 in the graduate school of management and economics at Sharif University of Technology. Initially, background and models were reviewed, and then the research theoretical framework was developed accordingly. In addition, since the subject was rather new, a qualitative research method by... 

This study aims to solve weekly Flight Frequency Determination and Aircraft Maintenance Routing Problem (AMRP) simultaneously. The objective function here is to maximize the total net profit of an assumptive airline with predetermined airfare and origin-destination market demand. All the needed constraints regarding AMRP is added to the modified version of original model which proposed by Ghafoori in 2011. On the other hand, while this kind of model is based on travelling salesman problem, the occurrence of sub-tours is inevitable. Thus, the model will be, secondly, restricted with more constraints which help eliminate infeasible solutions. The proposed model, then, is tested for three... 

This work is mostly about the analysis of direct position determination (DPD) approach as an emerging approach in source localization. Different aspects of this localization has been considered and some improvement techniques has been addressed. DPD is known as a replacement for the conventional 2-step localization approach in which the location of the target is estimated via the estimation of some interface parameters such as time of arrival, angle of arrival and etc. The main focus of this thesis is on the sensor placement problem in DPD in order to find an optimal configuration for the sensors to achieve the best accuracy in the estimation process. In this regard, the formulas of the... 

It has been reported that in some organizations despite delegation according to its concept, some of the organization members don’t have an internal motivation to use the autonomy that has been delegated to them. This problem might have different aspects. From the self-determination theory perspective, this might be because of unsatisfied basic needs of the person. For example, if all options the person has, are desirable or all of the options are undesirable and the person can’t choose between them. This might result in unsatisfied basic needs of the person. Due to these conditions, there is a probability that she won’t have an internal motivation to use autonomy. In some researches, it has... 

In the first section of this research, we have developed a simple and rapid colorimetric method for determination of tizanidine using citrate capped gold nanoparticles. Under optimal conditions, the AuNPs easily aggregate upon addition of tizanidine and the solution color changes from red to gray. This color change was followed using a UV-Vis spectrophotometer. The detection limit was calculated to be 0.48 µM. The method was successfully applied for determination of tizanidine in Spalex© tablets. In the last section, the anti-aggregation effect of Hg(II) on the tizanidine-AuNPs system was utilized with the aim of developing a colorimetric method for detection of Hg(II). Addition of... 

This thesis seeks to answer the following research questions: 1-How customers’ engagement with social media activation campaigns is conceptualized and operationalized? 2- What are the main antecedents of customers’ engagement with such campaigns? 3-How customers’ engagement with these campaigns affects brand image? The first research question is addressed in the first section of this research and includes five phases. Using the conceptualization of engagement in psychology, marketing, information systems, and some other fields, Phase 1 conceptualizes customers’ engagement with social media activation campaigns. This phase offers a comprehensive definition of this construct and discuss the... 

The concept of causality٫continually٫from the seventeenth century٫ As yet has been debated between philosopfers and partly physicists. This diversity of opinions rely on their’s ontologic and epistemologic positions. In the article, is attempted to compare causality in the philosophy of contem -porary(west) and Quantum physics with Islamic Philosophy (according to motahhary) In first chapter, universal hypothesizes and reasons of requirement to analyze causality is expressed. In second chapter,we turn to views of four famous hilosophers in the seventeenth and eiyhteenth century: locke ,Berkeley, Hume, kant. In third chapter, we attend to some current approach the recent philosophers... 

Impedance measurement is one of the most efficient electrochemical methods to investigate the mechanism and kinetics of electrode reactions. This method can detect the steps of successive or parallel electron and mass transfer chemical reactions based on measuring the response time constant. The method of showing results, commonly known as Nyquist diagram,which is based on drawing real and imaginary components of the impedance, with respect to each other in different measurement frequencies, is very useful for determining the mechanism of electrode reactions and the kinetic measurements. The main objective of this thesis is totheoretically determine the impedance response of six... 

Mode extraction in photonic and quantum-well structures requires solving transcendental equations and applying complex root searching methods, which incurs a diversity of numerical obstacles. In this thesis, the most effective methods for derivation of complex roots in such equations are investigated and analyzed. Thus the complex modes of an arbitrary one-dimensional photonic structure are extracted with highly adjustable precision and accuracy. The improper modes, i.e. solutions of the improper dispersion equation, are also studied and extracted by exploiting numerical methods. After this step, the migration of modes caused by changing the physical parameters of the structure is...