Sharif Digital Repository

Several dust storms originated from western countries deserts of Iran hit different cities in Iran and substantially elevates PM10 levels. To the date, some studies on trend and origin of the dust storm have been carried out. However, not enough information is available on the contribution of different deserts around the country to the aerosol concentration in Iranian cities. In this study, the deserts of potential dust sources have been identified and their contributions to PM10 concentration in Tehran have been investigated. The PM10 data collected over a 5 year period from 2006 to 2010 at monitoring stations in Tehran were used. A statistical approach was implemented in order to determine... 

Reduced-order modeling (ROM) is a novel approach in all realms of computational science including reservoir simulation. Among various ROM methods, Trajectory Piecewise Linearization (TPWL) is on its evolution for reservoir applications. Previous investigations reflect promising future for incorporating TPWL into the next generations of enhanced reservoir simulators. In this work, we employ TPWL to investigate the claimed efficiency, robustness and accuracy of this method as a surrogate simulator for a developed reservoir simulator. The self construction of the used simulator gives us the opportunity to explore this method and to examine previous assertions on the subject. The efficiency of... 

In this work, A new hybrid approach is presented to optimize a trajectory of Micromechanical Flying Insect in an obstacle reach environment. Here, a singleobjective Evolutionary Algorithm is utilize for finding solutions corresponding to multiple conflicting goals, which include minimizing the length of the path while maximizing safety margin by avoiding hard and non-moving obstacles. On the other hand, dynamic constraints of Micromechanical Insect such as maximum and minimum attitude angles and speed should be taken into account. In order to reduce the computational cost, a novel hybrid two-layer procedure is suggested for trajectory optimization. In the first layer, the algorithm generates... 

Bohm-de Broglie theory is an alternative for standard quantum mechanics for explaining the bizarreness of micro-phenomena. This theory is casual and deterministic,but endows with nonlocal and contextual characters. Up to now,two different approaches presented: One is known as Bohm-Hiley (BH) formalism and the other is Dürr-Goldstein-Zanghí (DGZ) representation. In BH formalism, quantum potential has a significant role, according to witch peculiar phenomena such as quantum tunneling, two-slit interference and chemical bond are explained. Active information is also another important rotion introduced by quantum potential. In DGZ approach, however, the foundation of Bohm theory is based on... 

The formation flight of satellites corresponds to a group of small satellites, performing the mission of a presumed larger and more expensive satellite. Usually mission designers tend to put these satellites in such orbital configurations that their trajectories do not intersect. Although a stable configuration in a certain collision-free orbit is desirable for long term purposes, most of the missions including maneuvers like forming or changing a configuration and inserting new satellites need to be planned using a proper path planning algorithm. In this thesis, a path planning algorithm is suggested that acquires the optimal and impact-free trajectories for a group of satellites for... 

Legged walking and climbing robots have recently achieved important results and developments, but they still need further improvements and study. The spider modeled as an eight-legged system. Legged robots have a body and a number of articulated legs which originate from the body and are put on the ground to hold robot’s weight or are swinging in the air to their new position. Each leg as a kinematic chain can be viewed as a manipulator that acts like a limb and contributes to the overall position and equilibrium of the structure. In order to evaluate and create an effective legged robot, the idea is to draw inspiration from nature. Spider robots present very good performances in terms of... 

Bohm theory is an alternative for standard quantum mechanics which, provides a deterministic description for physical microsystems. In this theory every physical system, describes as a quantum particle which guided by a correspondiente wave. In stationary states every wave-particle, depends on its initial conditions, is at rest in different points. As an example in hydrogen atom, stationary states means electron, with constant radius and polar angle, has a circular motion in planes which is parallel with xy plane. In this thesis the stationary trajectories of hydrogen atom has been reconsidered and new trajectories are sketched. Also by extension the discussion to the macrosystems, we study... 

The main idea in this project is investigation of multidimensional recording brain signal (ECoG) for estimation of 3D arm trajectory. First we introduce a general structure with variable blocks, in this structure we have many ways to estimate hand trajectory and obtain different result. By statistical test we find the best state of this structure and apply it on other dtae set trials. Electrocorticography (ECoG) has seen recent use in this regard because it offers a higher spatiotemporal resolution than non-invasive EEG and is less invasive than intracortical microelectrodes and have been shown to contain reliable information about the direction of arm Trajectory and movements. We using... 

One of the most interesting and at the same time the newest methods to launch a satellite into space is Air Launch or Launch throw the mother aircraft. The placement of the satellite into space by a rocket in specific altitude and speed is separated from the mother aircraft, takes place. The most problems in multi stage rocket launching is trajectory optimization to reaching the maximum height. The survey was conducted using classical optimization methods, which is derived the equations for the gradient based on the calculus of variations. that can be used or modified for emissions control wings and changing the direction of thrust exhaust. It should be noted that in the model of rigid body... 

Passive source localization accounts for the identification of the position and velocity of an object that emits electromagnetic/sound waves. This concept suggests various civil and military applications such as localization of the cellular phone users for emergency services, navigation, localizing radar and sonar sources. Received Signal Strength (RSS), Time of Arrival (TOA), Time Difference of Arrival (TDOA) and Frequency Difference of Arrival (FDOA) of the emitted signals are commonly used for position finding. Among all these measurement methods, localization using TDOA and FDOA is highly accurate and needless of any time synchronization between the source and the sensors. Common methods... 

Nowadays, robots are become more common in many important applications, such as academic and industrial issues. One of the most important robots are Multi-Arm manipulators which are used in many application such as moving objects, coloring, automatic welding and etc. Working with this kind of robots needs some vital attentions like planning their moving path. It is Because of the large number of obstacles that they face with in the path. Therefore, not only robots are not allowed to collision with themselves, but also they must not touch the obstacles. In the other words, they need Path planning. Generally, the equations of these robots are nonlinear. Therefore, computers and numerical... 

In this thesis, coupled trajectory and attitude control of an exoatmospheric interceptor is investigated. The interceptor is considered to track and intercept orbital targets in its terminal phase using an infrared strapdown seeker. Attitude control system uses its thrusters in order to keep permanently the detector toward the target in both elevation and azimuth directions. Detector is attached to the body. Divert thrusters generate acceleration perpendicular to the longitudinal axis of the interceptor to correct the trajectory. It is assumed that the interceptor has mass asymmetries. Transltional and rotational dynamics are coupled. Therefore, in order to improve the performance of... 

An optimal trajectory for flight through Microburst wind shears is designed which minimizes the maximum deviation from desired trajectory With respect to optimal control methods. The suitable performance of airplane retrieval in abort landing and landing phases at microburst encounter is achieved by influence of mentioned design in worse case of wind fluctuation and variation. 3D Vicroy microburst model is selected to investigate its effects on 6 DOF jet engine aircraft EOMs. Above optimal control problem is solved using gradient method of SD . Furthermore, sensitivity of optimal trajectory to lateral and longitudinal location of microburst, microburst parameters, throttle setting and... 

In this project, modeling and control of grasping phase of flight is investigated inspired by birds’ aerial hunting. For this purpose, grasping mechanism and its challenges in flight is studied. In the following, an explanation about gripper, its design and its performance in flight is given. Both 1-DOF and 2-DOF gripper is modeled. Then, the simulation is evaluated during different test cases. After modeling, optimum trajectory for an air-vehicle in grasping phase is studied and analyzed. When using a 2-DOF gripper instead of a 1-DOF gripper, the vehicle is capable of grasping in different positions and attitudes. Therefore, the results of trajectory generation show more chances of grasping... 

Toll Pricing as a means to relieve traffic congestion has received significant attention by transportation planners recently. Inappropriate use of transportation networks is one of the major reasons that cause congestion in networks. Toll Pricing is a method of traffic management which guides the traffic flow to proper time and path in order to reduce the total delay in networks. This thesis investigates a method for solving Minimum Toll Revenue problem in real and large scale transportation networks. The objective of this problem is to find tolls that simultaneously cause users to use the transportation network effectively and minimize the total toll revenues that must be collected.... 

Passive Location is to obtain the location and velocity of a radio source using a source-generated signal in the environment and extract its parameters, which today have many applications in controlling security activities, tracking people and vehicles, emergency services, radar, Sonar, electronic warfare, and etc. . The location of a source is obtained by using a variety of methods such as received signal strength (RSS), signal angle of arrival (AOA), signal time of arrival (TOA), time difference of arrival (TDOA), and frequency difference of arrival (FDOA) of received signals. Many studies have been done in measuring and extracting data and solving the equations. However, little research... 

In this thesis, satellite aided capture of spacecraft around Jupiter is optimized with the final goal of capture into a circular orbit around Europa. The cost functions of the multi-objective optimization process that should be minimized are: 1) summation of the propulsive ΔVs, 2) the total duration of the capture scenario, and 3) the integral flux of the energetic electrons and protons during the maneuvers. In this study, the spacecraft trajectory is modeled by patched conics method and is optimized by metaheuristic methods of genetic algorithm and simulated annealing. In some cases, interior point method is used for improving the final converged solution. Due to the limitations of... 

In this Thesis, the necessary steps to implement near-optimal atmospheric flights in order to create micro and partial gravity condition has specified. This documentary has been prepared in a comprehensive way. The goal of this project is to reach the optimal throttle and elevator inputs and consequently optimal paths to perform the maneuver with maximum time. The basis of my work is to integrate two methods of tabu search and continuous ant colony system in order to find the best match for inputs. As a result, the aircraft’s proper inputs as a function of time can be accommodated. The constraints here refers to the safety of the flight, which are maximum operating speed, stall angle of... 

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 this thesis, the optimal trajectories of a spacecraft in the binary asteroids system is studied. The objective functions of optimal trajectories in these system are the maximum coverage of the asteroids surface and minimum time and fuel consumption. For this purpose, the dynamic of binary system is modeled. The binary system of 1999 KW4 is selected as a case study. The ellipsoid-sphere model is a good approximation for the case of this study. In this model, the asteroids orbit in a circular orbit around each other in a spin-spin-orbit resonance configuration, in which the asteroids’ rotational velocity is equal to orbital mean motion. Then, the equations of motion of the spacecraft as the...