Sharif Digital Repository

In this thesis, optimum set of satellite constellations for regional navigation has been investigated. The cost function is the required multiple coverage for navigation in the Iran region with the lowest possible positioning error. In the satellite navigation systems the GDOP (Geometric Dilution of Precision) is a quantitative measure which is usually used to determine the effect of satellites’ orbits geometry on position error estimation. The lower the GDOP, the more precise the navigation would be. In fact, GDOP relates computed satellite-receiver range error to position estimation error. This thesis has two major parts; modeling and optimization. In the modeling of the problem,... 

Nowadays, power systems and substations are the most important components of the vital infrastructure of a country, which handle the production, transmission and distribution of the electrical energy. Automation systems increase the efficiency of the power industry while making remote control possible, but the use of computer-based control systems is a potential field for cyberattacks which may cause equipment destruction and electricity network destabilization. One of the main requirements for the utilization of digital substations is the synchronization between different equipment used in it. Several algorithms and protocols have been proposed so far for time synchronization in distributed... 

The development of technologies and some defects in medicine caused to emerge a new approach called precision medicine. Unlike the traditional medicine, medical experts do best treatment for each patient based on his genetic characteristics in this approach. Predicting drug response on cancer cell lines is one of the most vital challenges in this area. Various approaches have been proposed to construct predicting models while the substantial distinctions between resistant and sensitive cell lines had been neglected in them. Here, we propose a new approach for constructing the predictive model. In our approach, we utilized the distinctions between sensitive and resistant cell lines and also... 

Nanopositioning is technology of positioning & manipulation of Nano-scale object. This technology can be considered as one of the fundamental necessities in Nano & Micro research and fabrication and made lots of unbelievable advancement in researches and technologies. There are lots of mechanical systems designed for large scale positioning with sub millimeter resolution, but when it’s come to Nano scale, the range of access should be limited to some micrometer. Also in Nano-scale motion some difficulties like backlash, stick-slip and friction is phenomenon. For increasing the workspace using coarse and fine positioning systems may be an appropriate method. In this method a fine positioning... 

The purpose of this project is to detect the instantaneous frequency of an unknown signal which has a frequency range from 2GHz to 18GHz, and its amplitude is limited. In the first step, this signal is amplified, and its amplitude is limited and then it is converted to a digital sequence using a mono-bit scheme and entered the FPGA through an ultra-fast serial port. After that, the algorithm of this project is supposed to do two main processing stages on the received stream of pulses. Detection should be performed in the first phase. It means that it should be determined whether the received pulse sequence is a random sequence made by noise or an almost regular sequence due to a sinusoidal... 

The micro-scale channel creation in Osteochondral scaffolds is a prominent issue in tissue engineering. In this project we tried to identify the relevant parameters to obtain the method for injecting a biodegradable photo polymer to achieve a micro channel by predictable size.Due to inadequate accuracy in measuring the properties of the non –Newtonian working fluid, it was decided to use the Newtonian fluid equations in this study. The relevant equations for injecting the liquid under constant pressure were extracted. The modeling and design of micro syringe system was then completed. Using the made set up experiment to measure the fluid viscosity were performed.The next step was the... 

Nanopositioning is a technology for moving a target object within nanometer (10-9 meter) resolution. Nowadays nanopositioning stages have emerged as an important technological advancement in hi-tech applications, including scanning probe microscopy, lithography, nanometrology, fabrication and assembly of nanostructures and beam steering for optical communication systems. To achieve nanometer resolution the stage must focus on a few tens of micrometers travel range. The combination of piezoelectric actuators and monolithic compliant mechanisms can provide a smooth motion without friction, wear, and backlash. So, piezo-driven compliant mechanisms are used widely in nanopositioning systems. The... 

Monitoring of soil moisture plays an essential role in correct decision making and implementation of any closed loop control system in precision agriculture. On the one hand, continuous using of a lot of moisture sensors and monitoring of soil moisture via direct measurement is restricted by practical prohibitions. On the grounds that activation of a lot of sensors continuously requires communication of a large amount of information and causes high power consumption for a moisture monitoring system. On the other hand, using remote sensing methods such as satellite methods, for moisture monitoring in arbitrary spatial and time resolution for control purposes, is not practically possible. The... 

The Large Hadron Collidor (LHC) will increase its luminosity to more than 10e35 cm-2 s-1. The large amount of data rates will provide enough datasets needed to probe rare Higgs processes, study the scattering of longitudinally polarized W bosons and physics beyond the standard model(BSM). In the upgraded version of the LHC, called High Luminosity LHC (HL-LHC), the number of simultaneous interactions per bunch crossing, aka pile-up, increases to 140-200. The large number of pile increases the possibility of confusion in distinguishing vertexes of interest due to the contamination from non-interesting vertexes. One of the methods to mitigate the pile-up, complementary to the precision tracking... 

The distance measurement is the corner stone of the modern cosmology. They are measured via ”Doppler Effect”, accordingly the distances in cosmology are obtained in red-shift space. Despite the cosmological background expansion, the peculiar velocities due to the local density contrast distort these measurements. One of the main challenges in upcoming cosmological studies is to distinguish the peculiar velocity effect from the background expansion.Supernova Type Ia as standard candles can be think of a crucial observation to address the above problem. In this thesis, we study the effect of cosmological perturbations on distance-redshift relation of the SNIa. The corrective effects are from weak... 

Quantum entanglement and superposition are wonderful and mysterious phenomena of quantum mechanics. By means of quantum entanglement, two or more systems become partner in state of each other . As a result, measurements on each of these systems affect the status of other systems. Quantum superposition allows a system inhabits several of its possible quantum states simultaneously. These two features are applicable in many technologies in present age. Photons, as an quantum unit of light, are appropriate candidate for utilization these properties. Because they are robust to decoherence and for their preparation exist various methods. Hence, we interested to generation of quantum states of...