Sharif Digital Repository

In airlines, the problem of ‘flight crew scheduling’, as a part of the organization resources, holds great importance. Furthermore, considering the numerous and specific regulations regarding the working hours of flight crew, as well as constraints resulted by origin, destination, and time of each flight, this problem is also highly complex. The most significant challenge in solving this problem lies in the “construction and selection of the crew pairings” In this research, first, according to the literature, definitions and regulations necessary for the problem are stated. Then the problem is modeled as a "set covering problem," in which the rows of the problem correspond to flights which... 

In this thesis, our aim is to simulate steady and transient operation of a turboshaft engine with a free power turbine. For better understanding of physics of the problem, nested loops method is used in order to simulate the steady state operation. Furthermore, methods based on steady operation are used in simulating transient behavior of the engine. Scaling methods are used to extract performance characteristics of the engine components. It is assumed that performance characteristics have similar behavior in high engine shaft speeds. Bearing this in mind, validity of our simulations are confined to such high shaft speed conditions. In addition, for off design analyzes it is assumed that... 

This research deals with the Unrelated Parallel Machine Scheduling (UPMS) problem with sequence dependent setup times and release dates and machines eligibility. The studied objective is the minimization of total tardiness and earliness.The due dates and release times of the jobs are distinct which complicates the problem. Two mixed linear integer programming models proposed to solve the research problem optimally in small size instances.The problem is shown to be NP-hard in the strong sense.As it is not possible to solve medium and large size instances in approporaite time, a metaheuristic algorithm based on tabu search developed. Several versions of algorithm are obtained based on... 

Nowadays, stroke is known as one of the main reasons for death and disability. Statistical researches have shown that the number of stroke survivors is growing. Assessing stroke stage is one of the vital requirement of effective rehabilitation. Since the recent decades, new methods to assess upper extremity movement quality based on movement kinematic have been proposed in the literature. These methods quantify movement quality with the use of kinematic indices. In this study, repeatability and reliability of the proposed indices have been evaluated in a functional motion of daily activity consisted of diverse tasks. In this study, calculations were done on captured data of hand's movement... 

In the recent years, photonic crystal (PhC) devices vastly have been paid attention due to their ignorable loss, very low group velocity, flexibility in shape and dimension.In this thesis a PhC coupled cavity ring known as superresonator is introduced and its properties and applications is studied. Also modes of the structure are extracted through both coupled-resonator model and FDTD method, and two of its application is described and studied. Add-drop filter is one of the essential devices in WDM systems. First, an application of superresonator in designing add-drop filters is explained and a novel filter based on the superresonator is introduced and analyzed by FDTD and coupled mode... 

First, we peruse the intraction between a quantized light and a two level atom which has been described by Janes-Cummings-Paul Hamiltonian. By solving Heisenberg equations in Fourier space and describing electric field by a generalized-transverse Green function, we obtain spectral density for a quantum dot which is in the strong coupling to a slab photonic crystal cavity. Afterward, by solving Shrouding equations precisely we demonstrate when quantum dot is in a very strong coupling to cavity, rotate wave approximation is not reliable anymore. It means that if coupling constant gets comparable to cavity mode frequency then the prevalent approach to solve this Hamiltonian will not be correct.... 

Cavity Quantum Electro-Dynamics (CQED) in Weak, Strong and Ultra-Strong coupling Regimes are studied. A MATLAB m-file is written which is able to solve any arbitrary CQED configuration. This program demands input data such as number of Quantum Dots, number of energy levels of each Quantum Dot, energies of each energy level of Quantum Dots, Number of cavity modes, eign-frequency of each cavity mode, coupling constant, dipole strength of each allowed transition of Quantum Dots and initial state of system from user and begins to solve the Schrodinger equation for annihilation and atomic ladder operators. In addition, coefficients of each possible ket will be calculated. Since, any approximation... 

In this project, we were intended to study the ultra-strong coupling in optical waveguides. Hence, we analyze the interaction of an electromagnetic wave with a quantum well embedded in a dielectric slab waveguide. First, we designed a QW with and alloys, which the energy of its electron-heavy holes transition is . By exploiting the envelope function approximation, we derived the wavefunction of electrons and holes, their eigen-energies, and the dipole moment of electon-holes. For finding the wavefunction of holes and their eigen-energies, we used the Luttinger Hamiltonian. Next, we calculated the electrical susceptibility of a three level quantum system (as a model for QW), by using... 

Thin Walled Beams are widely used in engineering applications with the minimum weight design criteria, ranging from civil to aerospace and many other industrial fields. The weight reduction of the beam leads to importance of the dynamic behavior of the structure. Frequently used thin walled beams have low torsional stiffness and their torsional deformations may be of such magnitudes that it is not adequate to treat the angles of cross section rotation as small. When the vibration amplitudes are moderate or large, the geometric nonlinearity must be included and some new phenomena which do not exist in linear torsional dynamic come into play. Unfortunately, the equations of motion of nonlinear... 

In the recent years, field effect transistor has been made by using graphane. But there has not been any study about bipolar transistor. Bipolar transistor can’t be constructed using graphene due to the fact that its band gap is zero. So in this thesis, in an attempt to remove this difficulty, the bipolar transistor made using graphane has been investigated and their property has been compared to those of three dimensional silicon transistors.
At the beginning of the thesis, we will have a review of graphane diode and will consider the procedure for evaluating its current which would be the report of what has been done sofar. After that we made graphane transistor using graphane diode... 

In this M.Sc. thesis the behavior patterns of the cavity quantum electrodynamics of complex systems are analyzed, such systems are quantum optic multi-partite systems and consist of an arbitrary number of quantum dots in interaction with arbitrary number of cavity modes.
First, the coefficients matrix of the ket sate of the system was measured, in order to achieve it; the general time-dependent state of the most general possible system was specified. Its related Hamiltonian was written, and finally the Schrodinger equation was measured in different coupling regimes. It was done in Schrodinger picture without any approximation.Second, the presence probabilities of the quantum dots of any... 

One of the attractive fields of applied quantum mechanics in recent two-three decades is the field of quantum computing. Up to now different substrates have been proposed for a quantum computer. One of them is cavity quantum electrodynamics in which some quantum systems with finite energy states like atoms interact with quantized Bosonic modes like photons inside a cavity. In this dissertation we study a particular structure in this substrate. This structure consists of some quantum dots inside coupled cavities. Since we would like to build these cavities in a photonic crystal slab, we first introduce two new methods for analysis of this type of crystals. These methods are much faster than...