Sharif Digital Repository

Deep Neural Networks (DNNs) are widely used as a promising machine learning method in different applications and come with intensive computation and storage requirements. In recent years, several pieces of prior work have proposed different accelerators to improve DNNs processing. We observe that although the state-of-the-art DNN accelerators effectively process some network layers of certain shapes, they fail to keep computation resources fully utilized for many other layers. The reason is twofold: first, the mapping algorithm is unable to employ all compute cores for processing some layer types and dimension sizes, and second, the hardware cannot perform data distribution and aggregation... 

A simple control system contains at least an actuator, a controlled link, and a foundation. These structures are not ideally rigid, this flexibility can appear willingly or unwillingly in any parts of the system or the connections between them. As a consequence of this flexibility, the movement of the controlled part will fluctuate unintentionally. In this thesis, a control system with rigid controller and flexible torsional base is investigated and controllers are designed and compared to reduce these unwanted vibrations. Finally, by implementing the controllers on the constructed system, the experimental results are obtained and compared with the analytical results.To fabricate the... 

In this thesis the attitude dynamics, simulation and control of a flexible satellite with CMG (Control Moment Gyro) actuator in three-dimensional slew and rest-to-rest maneuvers have been studied. The flexible satellite is modeled as a rigid hub and two flexible appendages. The bending and torsion of the flexible panels have been considered. The equations of motion have been derived using the Lagrange method and assumed-modes approach is utilized for converting the partial differential equations of structural dynamics into an ordinary differential equation set. The MATLAB and SIMULINK software has been used for simulation and validation of the equations of motion. The simulation and control... 

Many spacecrafts and satellites have long flexible components, the most common ones are the satellites with flexible solar panels, which are used to provide the satellite energy. The governing equations of the satellite rigid motion along with the solar panels vibrations are the combination of the coupled partial and ordinary differential equations. Various reasons, such as the satellite maneuvers and the external disturbances, cause the vibration of panels. Due to the dependence between the governing equations of the satellite rigid motion and the flexible components vibrations, these vibrations affect the satellite rigid dynamics and the control aims; therefore, in addition to the... 

Launch vehicle must overcome gravity and place its payload on determined orbit. Multi-staging of launch vehicles causes that the ratio of length to diameter become large and then launch vehicle behave elastically. In this study, the equations of motion using the Lagrangian approach drive at pitch plane. By adding elastic terms to control equations, the launch vehicle modeling is completed. Predictive model controller choose for control system.This controller is based on neural network. In this paper, the main concepts and neural network approach in this controller structure is introduced.Finally implementation of this method in Simulink environment for pitch control of a flexible launch... 

Control of two-arm flexible robot is studied in this research. The goal is to control the robot in order to carry a fluid tank installed in the top of the last arm, while the vibration of fluid must be damped. The equations governing the system are extracted by the energy method while Euler-Bernoulli beam is selected to model the elastic members. In order to develop the equations, all of the potential and kinematic energies due to rigid and elastic motions are calculated, then a proper controller is designed for the system to accomplish the considered missions. Since the system is classified as an under-actuated system, the exact feedback linearization method is not practical to control the... 

Precise adjustment of orientation is vital in many important applications of satellites. Besides, in order to have sustainable power source and to reduce heavy costs of launching deployable solar arrays with large area to mass ratio are utilized. The vibrations in these flexible parts and attitude dynamics of the main hub influence eachother mutually. Thus, simultaneous attitude and vibrations control is of noticeable significance. In this thesis considering new details such as multi-section solar panels, the governing dynamic partial differential equations (PDE) are derived via Hamilton principle. In order that errors arised from discretized models be eliminated and just using regular... 

The primary goal of this thesis is to develop a Fault Tolerant Control (FTC) system for a flexible satellite in presence of actuators fault and failure. The actuators of the satellite are including three magnetorquers and three reaction wheels on each principal axis. At first, the three-degree-of-freedom rotational motion of a rigid satellite with two flexible solar panels is modeled. The flexible panels are modeled through the assumed mode approach by a finite set of bending modal motion. The ordinary differential equations of their generalized coordinates are found using the Lagrange’s equation. Then, the dynamic model is validated by comparing the simulation results of the model to the NX... 

In this paper, the general research of impedance control is addressed for a robotic manipulator with a moving flexible base. Impedance control imposes a relation between force and displacement at the contact point with the environment. The concept of impedance control of flexible base moving manipulators (FBMM) is rather new and is being considered. The dynamic of manipulator is decomposed into slow and fast dynamics using singular perturbation method. New sliding mode impedance control method (SMIC), using an element on the end effector is proposed for high precision impedance control of FBMM. The sliding mode impedance control method as a robust impedance control law is derived for the... 

Piping process is the most important part of industries projects which pay attention to construction and installation of industrial pipelines and its facilities. In the meantime, due to increasing demand of industrial units to construction and development projects, planing and scheduling the piping is necessary. We review and discuss various aspects of the piping process, optimization process and the related scheduling literature that is called Flexible Job Shop Scheduling Problem. Then, to solve the problem, considering the real world assumptions, a mathematical model, is developed and a heuristic algorithm is introduced. Also, in order to determine an appropriate bound for the optimal... 

Considerable research work has been dedicated to the development of structural control systems to improve the performance of structures and reduce the casualties resulting from earthquakes. It is generally accepted that semi-active control systems result in better structural performance compared to what can be achieved using passive systems. However, it has been observed that the majority of the performance improvement obtained from semi-active control systems stems from the reduction of brace flexibility effects, rather than the control algorithm used. In this study, it is attempted to utilize this fact to improve the performance of passive control systems, or develop simple semi-active... 

Thorough investigation of the Cloud-RAN (C-RAN) architecture has recently shown that CRAN can bring advanced cooperated and coordinated processing capabilities as well as the multiplexing gains toward future radio access networks. The baseband processing of each base station instance can now be flexibly split into smaller functional components, that can be placed either at remote radio units (RRUs) or baseband units (BBUs), depending on the available resources. In this project, we investigate recent implemented methods in C-RAN. also, we propose, develop and implement new architectural frameworks for C-RAN that can support both a flexible functional split and a new functional splitting known... 

In recent years, boundary control (BC) approach for distributed parameter systems and their applications has demonstrated that it can be a well-intentioned candidate for control system design. In this approach, the main focus is on the boundary actions, where the actuators are aligned on the boundaries of the media. BC may be considered as an ideal approach, especially from applied and engineering point of view, because it deals only with actuators and sensors along the boundaries. Moreover, the problem of boundary stabilization and motion control of flexible crane systems has been one of the remarkable problems for control engineers. In this research, we contemplate the boundary control... 

The mechanism by which plasticity in millions of synapses in the brain is orchestrated to achieve behavioral and cognitive goals is a fundamental question in neuroscience. In this regard, insights from learning methods in artificial neural networks and in particular the idea of backpropagation seem inspiring. However, the implementation of BP requires exact matching of forward and backward weights, which is unrealistic given the known connectivity pattern in the brain (known as "weight transport problem"). Notably, it is recently shown that under certain conditions, error backpropagation through random backward weights, can lead to partial alignment of forward and backward weights... 

Hydrodynamics of flow is affected by physical and biological interactions between flow and aquatic vegetation. This study represents the role of array distribution on lateral dispersion in emergent aquatic vegetation using two flexible and semi-rigid models. Experiments were carried out with three different arrangements, including random, staggered, and in-line. The Reynolds numbers at the stem scale ranged from 120 to 690, and the stem densities were 1% and 1.44%. Furthermore, the effects of stem flexibility and, specifically, stem resonance on lateral dispersion were examined. An image processing technique was used to measure plume width and calculate lateral dispersion. It was found that... 

The purpose of this research is to investigate the movement and diffusion of pollution transversely around a set of stems of flexible plants with different materials and to observe the effect of resonance on lateral dispersion. Two stem samples of polyurethane and nylon were used under different Reynolds numbers. Vertically uniform dye is injected into the flow, and the evolution of the dye plume along the flow is measured using image processing. By measuring the displacements of selected stems we study the effects of resonance on stem vibration and lateral dispersion. The experiments were also conducted for no-stem dispersion and the results were compared with those with plant samples. The... 

Because of seismic flexibility, aesthetics, economic advantage and rapid construction of reinforced soil walls, application of these walls has raised tremendously since 1970’s. The early reinforced soil retaining walls used metallic srips to reinforce the soil with precast concrete panels as facing, however, since 1990’s using of geosynthetics to reinforce these walls with modular concrete block facing have replaced the old fashion. In this study, a finite difference code was developed in FLAC software. After verification of the numerical modeling procedure, a wall with 3.6m height reinforced by geosynthetics was simulated. In the course of numerical simulations the stage of counstruction,... 

Alternative fuels are considered as a solution to increase energy security, reduce dependence on conventional fossil fuels (gasoline and diesel), and reduce greenhouse gas emissions. In this context, bioethanol has been very much considered in recent years. This fuel is combined with gasoline and used by cars. Flexible fuel vehicles are cars that can be used in various blend of gasoline and ethanol. Ethanol has a higher octane number than gasoline, and its mixture with gasoline increases the number of octane fuels. However, this fuel has a lower thermal energy than gasoline, which increases the fuel consumption of ethanol and gasoline relative to pure gasoline. The purpose of this study is... 

In this study, the behavior of a new innovative bracing system under cyclic loading and according to AISC code is investigated. An Ideal bracing system, in addition to having sufficient stiffness, should have a suitable ductility. Also, in order to prevent inelastic behavior of other structural members, braces, in addition to possessing high architectural adaptivity, must be able to contain the damage within itself and behave like a fuse. Three specimens with different sections, IPE100, HEA100 and 2UNP100, were designed and tested. The results of these tests represent an elastic- (approximately) perfectly plastic behavior of the brace if an appropriate section is used. Moreover, this bracing... 

Flapping motions of flexible wings generate dynamic forces. These forces include aerodynamic forces and inertial forces due to angular acceleration of wing mass, that cause aeroelastic deformation of wings. In this thesis a method is presented by use of a software and some experimental test conditions to study elastic behaviors and aerodynamic forces of flexible wings. A high speed camera records motion of wings in hovering condition and then these images is processed with software to recognize deformations (such as deflection, torsion, etc.) and aerodynamic forces due to them. Afterwards aerodynamic model and deformations is combined for better modeling. Finally we can compare results with...