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    Evaluation of Effective Factors on Utility of Urban Bus for Work Trips (Case Study: Regular Bus of the City of Tehran)

    , M.Sc. Thesis Sharif University of Technology Gholi, Hadi (Author) ; Kermanshah, Mohammad (Supervisor)
    Abstract
    Improvement of public transportation systems through attention to service quality of these systems, is important in order to increase the use of these systems. Various quantitative and qualitative attributes of travel are known effective on service quality of public transportation. The investigated factors in this research, with refrence to regular bus system of the city of Tehran, are: in-vehicle time, fare, crowding and headway. For this purpose, the stated preference data of the respondents who travel to work by regular bus, collected. The survey was conducted during the last month of spring and 360 questionnaires were completed. Stated preference scenarios relating to aforementioned... 

    Investigating the sources of heterogeneity in passengers’ preferences for transit service quality

    , Article Journal of Public Transportation ; Volume 24 , 2022 ; 1077291X (ISSN) Gholi, H ; Kermanshah, M ; Reza Mamdoohi, A ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    Improving the service quality of public transport is necessary to maintain the loyalty of current users and attract new travelers. Past studies show that users’ preferences for transit service quality are heterogeneous, but recognizing the factors describing this heterogeneity has not been investigated in depth. This paper aims to evaluate the sources of heterogeneity in passengers’ preferences for service attributes of bus transit regarding the regular bus system in the city of Tehran. Four attributes of bus travel, including in-vehicle travel time, fare, vehicle crowding, and headway, were considered. Stated preference (SP) data of 360 commuters with work purpose was collected through... 

    Analysis of Degradation for Laminated Notched Plate in Micromechanics by “Strain Energy Release Rate” Method and Illustrations the Results in Ansys

    , M.Sc. Thesis Sharif University of Technology Gholi Mesgarha, Payam (Author) ; Hosseini Kordkheili, Ali (Supervisor)
    Abstract
    By developing composites, difficulties of modeling of degradation of properties as stiffness is most considered. The recent advances in the modeling of degradations in stratified composites have led to improved models on all scales. Macro scales methods are good to estimate fracture but not to estimate the failure in micro scale (as microcrack) and moreover, they need many experimental data. Therefore by considering a stratified structure which contains fiber, matrix and intermediate area, mesoscale modeling method is most suitable. In this research Micromechanical Progressive Algorithm (MPA) is used. The method employed is Micromechanic Method of Fracture (MMF). In this work by developing a... 

    Enhancement of the MAC Layer of Mobile Broadband Wireless Access Network

    , M.Sc. Thesis Sharif University of Technology Gholi Ghasri, Monireh Allah (Author) ; Ajorloo, Hossein (Supervisor)
    Abstract
    Mobile Broadband Wireless Access technologies provide mobile users with broadband services, for example music downloading, online games and etc. IEEE 802.20 standard is one of the Mobile Broadband Wireless Access technologies , which has been published to support mobile users with high vehicular speed up to 250(km/h). The issue studied in this research is enhancement of MAC layer in IEEE 802.20 standard.
    By having this intention in mind we firstly developed a simulator for IEEE 802.20 MAC layer implementation , then we tried implementing 3 different approaches for connecting mobile users to a new network in order to analyze their performance. Then we provided a method for decreasing... 

    Advances in heuristic signal processing and applications

    , Book ; Chatterjee, Amitava ; Nobahari, Hadi ; Siarry, Patrick
    Springer  2013
    Abstract
    There have been significant developments in the design and application of algorithms for both one-dimensional signal processing and multidimensional signal processing, namely image and video processing, with the recent focus changing from a step-by-step procedure of designing the algorithm first and following up with in-depth analysis and performance improvement to instead applying heuristic-based methods to solve signal-processing problems. In this book the contributing authors demonstrate both general-purpose algorithms and those aimed at solving specialized application problems, with a special emphasis on heuristic iterative optimization methods employing modern evolutionary and swarm... 

    Development of an Evolutionary Algorithm Based on Surrogate Models to be used in Multi-disciplinary Design Optimization of a Flying Vehicle

    , M.Sc. Thesis Sharif University of Technology Ghoreishi, Mohaddeseh (Author) ; Nobahari, Hadi (Supervisor)
    Abstract
    In this research, multi-disciplinary design optimization (MDO) of a flying vehicle has been done based on the flight simulation. A meta-heuristic algorithm called Multi-objective Adaptive Real-coded Memetic Algorithm (MARCOMA) has been used for optimization. Since solving a MDO problem is a time consuming process, a RBF neural network has been used in the optimization algorithm as a surrogate model. The new algorithm, called MARCOMA+NN, has been tested with some standard benchmarks. MDO problem has six disciplines consists structure, aerodynamic, propulsion, guidance, control, and fire control. The MDO problem has 31 design variables and two objective functions. The objective functions are... 

    Optimal Design and Real-time Implementation of a Cooperative Guidance Algorithm against a Flying Vehicle

    , M.Sc. Thesis Sharif University of Technology Motie, Mahyar (Author) ; Nobahari, Hadi (Supervisor)
    Abstract
    A cooperative aerial system to defense a Ground Station (GS), against an Incoming aerial Targets (IT) is presented. GS is surrounded by given terrains and a group of homogenous Unmanned Aerial Vehicles (UAVs) are employed using a novel online guidance algorithm in a decentralized manner. The proposed algorithm includes loiter, midcourse and terminal phases. During loiter; UAVs follow an optimal circular path. IT is supposed to approach GS along an optimal low altitude trajectory with respect to the terrains. UAVs are informed the initial position and velocity of IT and they are unaware of IT trajectory. Each UAV decides on whether to engage with IT or not, and shares its decision with other... 

    Synthesis and Characterization of PVDF Magnetic Nanocomposite

    , M.Sc. Thesis Sharif University of Technology Hadi, Mina (Author) ; Forounchi, Massoud (Supervisor)
    Abstract
    PVDF (polyvinylidene fluoride) magnetic nanocomposite films were prepared by solution casting using two types of nanomagnetic particles: (i) magnetic nanoparticles synthesized by using an alkaline solution of mixed ferrous/ferric salts along with oleic acid as a coating agent at 70˚C; (ii) Fe3O4 nanoparticles prepared by hydrolysis of aqueous solution of ferrous/ferric salts with potassium hydroxide at room temprature. Scanning electron microscopy (SEM) showed that the PVDF magnetic nanocomposite had a porous structure with Fe3O4 nanoparticles dispersed inside the porous polymer matrix. The presence of crystalline magnetite within the polymer matrix was confirmed by X-Ray diffraction method... 

    Cooperative Search and Localization of Mobile RF Ground Targets, Using a Group of UAVs

    , M.Sc. Thesis Sharif University of Technology Effati, Meysam (Author) ; Nobahari, Hadi (Supervisor)
    Abstract
    In this project, a method for cooperative search and localization of RF ground moving targets by a group of UAVs is developed. It should be noted that UAVs are just equipped with GPS and directional sensors. Since there is fuel constraint for UAVs, they take fuel from a tanker whenever they require. Moreover, searching method enables the UAVs to see different parts of the desired area with almost uniform distribution. In addition, the proposed approach enables the UAVs to perform a local search with the aim of finding the targets having lost their signal during localization mode. Finally, based upon a fueling decision function the UAVs take turn, approach to the fuel tanker, and start... 

    Attitude Control of a 3DOF Quadrotor Stand Using Intelligent Back-stepping Approach

    , M.Sc. Thesis Sharif University of Technology Abeshtan, Peyman (Author) ; Nobahari, Hadi (Supervisor)
    Abstract
    In this research a novel intelligent back-stepping control method is developed. This method is robust to sensor noise and external disturbances. In addition, the controller is robust under model uncertainty. This controller does not need precise knowledge of system parameters. This method is based on three methods of: back-stepping control, least squares estimation and a fuzzy compensator. This controller is used to control quadrotor stand witch is like an inverse pendulum. In quadrotor stand modeling, the inverse pendulum effect is considered too, witch is one of the innovations of the research. By doing various simulations, the validity of controller is tested. Also the performance of the... 

    Cooperative Search and Localization of Aerial Targets, Using a Group of Fixed Wing UAVs

    , M.Sc. Thesis Sharif University of Technology pourhaji, Amir (Author) ; Nobahari, Hadi (Supervisor)
    Abstract
    Topic that is investigated in this article include identify and localization a number of aerial target penetrating into a protected by area by a swarm of UAVs is fixed wing. UAVs do not have any prior notice of positioning targets. In addition, it is assumed that lacks any radiation exploitable targets and thus use UAVs for Targets Detection from an active radar system. Obviously this article focus on developing a guidance algorithm UAVs to this particular issue and also as the targets participatory is localization algorithm. In addition, extraction type and performance characteristics radar system required and also performance characteristics of the class of UAVs, which is suitable to... 

    A New Method for Integrated Controller and Observer Design of a Nonlinear System Using Genetic Programming

    , M.Sc. Thesis Sharif University of Technology Khosroabadi, Saleh (Author) ; Nobahari, Hadi (Supervisor)
    Abstract
    The purpose of this paper is to design an integrated controller and observer (ICO) for a nonlinear system using genetic programming. ICO is a function that constructs control command directly from the measured state variables of the system. It means that, this function should imitate the behavior of the observer and controller and control the system with acceptable performance in different initial conditions, at the presence of disturbances and system uncertainties. The complexity of this design method, is not related to the complexity of the plant, in fact, the complexity in plant just effects at run time, but the design procedure does not change. So, if exact model of plant exist, using... 

    Development of Integrated Model of the Wastewater and Organic Solid Waste Flows to Minimize Environmental Impacts and Maximize Energy Recovery for a Residential Building

    , M.Sc. Thesis Sharif University of Technology Hadi, Hamid (Author) ; Avami, Akram (Supervisor)
    Abstract
    Nowdays much of the organic solid waste and wastewater is buried using centralized and traditional methods. This leads to many problems, including groundwater pollution, methane emissions into the atmosphere and rapid transmission of disease. In order to avoid these problems, using a decentralized approach can be a good solution. In this study, recovery of organic waste and wastewater of residential buildings using anaerobic digester as a decentralized way, have been examined. Using experiments, the optimum mass ratio of organic solid waste and wastewater is obtained as 80% and 20% respectively. Biogas production model is developed using mass balance and Balance of electrons in redox... 

    Parallel Multi-disciplinary Design Optimization of a Guided Flying Vehicle

    , M.Sc. Thesis Sharif University of Technology Darabi, Davoud (Author) ; Nobahari, Hadi (Supervisor)
    Abstract
    Multi-disciplinary design optimization (MDO) of a surface to air flying vehicle has been done in this research, on the basis of flight simulation. The MDO problem have five disciplines consists of aerodynamic, propulsion, guidance, control, and fire control. Multiple campaign scenarios are defined. The MDO problem has 31 design variables and two objective functions. The objective functions are flying vehicle weight and miss distance. A new meta-heuristic algorithm has been designed to solve multi-objective optimization problems. The new algorithm has been called Multi-objective Adaptive Real-coded Memetic Algorithm (MARCOMA). The MARCOMA can solve large-scale and multi-objective problems and... 

    Dynamic Modelling and Nonlinear Control of a Hybrid Powered Hexarotor for Precise Trajectory Tracking

    , M.Sc. Thesis Sharif University of Technology Saadat, Sepehr (Author) ; Nobahari, Hadi (Supervisor)
    Abstract
    In this Thesis, an unmanned multicopter with a new structure is modeled and a nonlinear controller is designed for it to track the trajectories precisely. The multicopter in this thesis, has six propellers with a hybrid propulsion system (a combination of fuel and electric propulsion system) that has the ability to carry more payload and maintain more flight duration compared to electric multicopters. In the beginning, the performance characteristics and technical specifications of the hexacopter are presented. For modeling, first the equations of six degrees of freedom movement of the hexacopter are derived by the Newton-Euler method. In the next step, the forces and torques applied to the... 

    Theoretical Investigation of Ab-initio MD Approach to Increase the Efficiency and Accuracy of VCD Spectrum Calculation

    , M.Sc. Thesis Sharif University of Technology Hadi, Hossein (Author) ; Jamshidi, Zahra (Supervisor)
    Abstract
    Understanding of the Molecules is the main purpose of the chemistry. Ab-initio molecular dynamics (AIMD) as a branch of the computational chemistry, tries to give us a deep comprehension of the molecule, and its chemical, physical and optical activities. This comprehension, relies on the accuracy of quantum mechanics, in addition to the speed of the classical mechanics. The mixing of the quantum mechanics and the classical mechanics could simulate activities of the atoms in the time-domain, provided the mixing is done with precaution. This, in turn, helps us to forecast the response of a molecule in different situations, and also translating the macroscopic phenomena in a nanoscopic... 

    Developing a Heuristic Filter Utilizing Firefly Optimization Algorithm: A Case Study on State Estimation of a Slung Payload from a Quadrotor

    , M.Sc. Thesis Sharif University of Technology Raoufi, Mohsen (Author) ; Nobahari, Hadi (Supervisor)
    Abstract
    The aim of the present thesis is to develop a novel heuristic filter by utilizing Firefly Optimization Algorithm for state estimation of nonlinear, non-Gaussian systems. The proposed filter formulates the estimation problem as a dynamic, stochastic one. The swarm intelligence of the fireflies enables the filter to find and track the best estimation. To estimate the states of a system, the model of the system is required. Hence, an 8-DoF quadrotor with slung payload system, as a case study, is modeled by the tensor method. In this case, as a highly nonlinear system, in order not to rely on extra sensors for monitoring swing-angle, the estimation of payload states is needed. In this regard,... 

    Development and Implementation of Multiple Model Filters for Online Identification and Compensation of Atmospheric Disturbances in Automatic Landing of Fixed Wing UAV

    , Ph.D. Dissertation Sharif University of Technology Sharifi, Alireza (Author) ; Nobahari, Hadi (Supervisor)
    Abstract
    In this study, a multiple model wind estimator is proposed to detect the wind type and to estimate the wind components as well as the states of a fixed-wing UAV without any direct measurement of the air data. Then, the identified wind model and the estimated states are compensated in the heuristic nonlinear model predictive controller during landing phase. For this purpose, a static multiple model approach is taken, comprised of four independent extended Kalman filters, each one is estimating the wind based on one of the four wind models including a constant wind, a “1-cosine” model, a wind shear and a microburst.Moreover, a new heuristic multiple model filter, called Multiple Model Extended... 

    Introduction of A Guidance Algorithm to Control A Quadrotor Approaching Time, Location, And Speed for Landing on A Moving Platform with Hardware in the Loop Simulation

    , M.Sc. Thesis Sharif University of Technology Tavalla, Ali (Author) ; Nobahari, Hadi (Supervisor)
    Abstract
    In this thesis a guidance algorithm is developed to control middle phase landing of a quadrotor on a moving platform. Middle phase guidance is consisted of approaching time, speed, and angle constraints. In the first step proportional guidance algorithms was studied. Then a six-freedom model of a quadrotor dynamic was developed. At the next step an appropriate guidance algorithm was developed to control a quadrotor for the mentioned constraints. Finally, the parameters of the algorithm were optimized by numerical methods. Monte-Carlo method used to validate this method. For this reason, 850 numerical simulations with random initial and final conditions were performed and the statistics... 

    Energy Aware Routing Algorithm with SDN in Data Center Networks

    , M.Sc. Thesis Sharif University of Technology Hadi, Azhar (Author) ; Koohi, Somayyeh (Supervisor)
    Abstract
    It is well known that data centres consume high amounts of energy, which has become a major concern in the field of cloud computing. Therefore, energy consumption could be reduced by using intelligent mechanisms work to adapt the set of network components to the total traffic volume. SDN is an efficient way to do so because it has many benefits over traditional approaches, such as centralised management, low capex, flexibility, scalability and virtualisation of network functions. In our work will we use the heuristic energy-aware routing (HEAR) model, which is composed of the proposed heuristic algorithm and the energy-aware routing algorithm. This work identifies the unused links and...