BRST quantization of noncommutative gauge theories

, Article Physical Review D ; Volume 68, Issue 10 , 2003 ; 05562821 (ISSN) Soroush, M ; Sharif University of Technology

American Physical Society 2003

Abstract

In this paper, the Becchi-Rouet-Stora-Tyutin (BRST) symmetry transformation is presented for the noncommutative U(N) gauge theory. The nilpotency of the charge associated with this symmetry is then proved. As a consequence of the spacelike noncommutativity parameter, the Hubert space of physical states is determined by the cohomology space of the BRST operator as in the commutative case. Further, the unitarity of the S-matrix elements projected onto the subspace of the physical states is deduced. © 2003 The American Physical Society

BRST quantization of noncommutative gauge theories

, Article Physical Review D - Particles, Fields, Gravitation and Cosmology ; Volume 67, Issue 10 , 2003 ; 15507998 (ISSN) Soroush, M ; Sharif University of Technology

2003

Abstract

In this paper, the Becchi-Rouet-Stora-Tyutin (BRST) symmetry transformation is presented for the noncommutative [Formula Presented] gauge theory. The nilpotency of the charge associated with this symmetry is then proved. As a consequence of the spacelike noncommutativity parameter, the Hilbert space of physical states is determined by the cohomology space of the BRST operator as in the commutative case. Further, the unitarity of the S-matrix elements projected onto the subspace of the physical states is deduced. © 2003 The American Physical Society

Workspace measurement of the surgeon's upper limb during an arthroscopy and three laparoscopy operations using inertial sensor systems

, Article 2013 E-Health and Bioengineering Conference, EHB 2013 ; 2013 ; 9781479923731 (ISBN) Soroush, A ; Farahmand, F ; Sharif University of Technology

2013

Abstract

The aim of this study was to determine the workspace of surgeon's body for designing more efficient surgical robots in the operation rooms. Five wearable inertial sensors were placed near the wrist and elbow joints and also on the thorax of surgeons to track the orientation of upper limb. Assuming that the lengths of five segments of an upper limb were known, measurements of the inertial sensors were used to determine the position of the wrist and elbow joints via an established kinematic model. subsequently, to assess the workspace of surgeon upper body, raw data were collected in the arthroscopy and laparoscopy operations. Experimental results demonstrated that the workspaces of surgeon's...

Effect of capillary tube's shape on capillary rising regime for viscos fluids

, Article 2017 International Conference on Nanomaterials and Biomaterials, ICNB 2017, 11 December 2017 through 13 December 2017 ; Volume 350, Issue 1 , 2018 ; 17578981 (ISSN) Soroush, F ; Moosavi, A ; Sharif University of Technology

Institute of Physics Publishing 2018

Abstract

When properties of the displacing fluid are considered, the rising profile of the penetrating fluid in a capillary tube deviates from its classical Lucas-Washburn profile. Also, shape of capillary tube can affect the rising profile in different aspects. In this article, effect of capillary tube's shape on the vertical capillary motion in presence of gravity is investigated by considering the properties of the displacing fluid. According to the fact that the differential equation of the capillary rising for a non-simple wall type is very difficult to solve analytically, a finite element simulation model is used for this study. After validation of the simulation model with an experiment that...

Unsteady Analysis of a Slinger Combustion Chamber by the Chemical Reactor Network Model

, M.Sc. Thesis Sharif University of Technology Soroush, Fariborz (Author) ; Farshchi, Mohammad (Supervisor)

Abstract

Up to early seventies, Gas turbine combustor design was very time consuming and costly process including trial and errors through test rigs. Over the time analytical-experimental relationships take place as one of the key rules in the design processes. With the increasing power of computer calculations, computational fluid dynamics find its way in the procedure. Obtaining a deeper understanding of flow conditions and geometry inside the chamber, a great reduction in production time and cost of revisions to rigs and samples were achieved. Finding a precise prediction of polluting elements like NOx (less than 10 ppm) after many run hours and enormous computing resources, CFD methods must...

Modeling and Simulation of Alcoholic Fermentation of Sugarcane Blackstrap Molasses

, M.Sc. Thesis Sharif University of Technology Soroush, Mohammad (Author) ; Yaghmaee, Sohila (Supervisor)

Abstract

Fed-batch fermentation is a valuable and cost-effective method for bio-based production of various products such as ethanol, which has various applications in various industries.In recent years, bioethanol production has been given special attention in many countries. For this reason, the mathematical modeling of production of these products is very important for their optimal and cost-effective production. Given the transient and dynamic nature of fermentation and its specific complexity, mathematical modeling of fed-batch bioreactors is difficult and complicated. In this research, an unstructured model was used to predict the production of ethanol from blackstrap sugar cane molasses based...

Detection of change to SSVEPs using analysis of phase space topological : a novel approach

, Article Neurophysiology ; Volume 51, Issue 3 , 2019 , Pages 180-190 ; 00902977 (ISSN) Soroush, M. Z ; Maghooli, K ; Pisheh, N. F ; Mohammadi, M ; Soroush, P. Z ; Tahvilian, P ; Sharif University of Technology

Springer New York LLC 2019

Abstract

A novel method based on EEG nonlinear analysis and analysis of steady-state visual evoked potentials (SSVEPs) has been processed. The EEG phase space is reconstructed, and some new geometrical features are extracted. Statistical analysis is carried out based on ANOVA, and most significant features are selected and then fed into a multi-class support vector machine (MSVM). Both offline and online phases are considered to fully address SSVEP detection. In the offline mode, the whole design evaluation, feature selection, and classifier training are performed. In the online scenario, the proposed method is evaluated and the detection rate is reported for both phases. Subject-dependent and...

Robust Control of Satellites Formation Flying

, M.Sc. Thesis Sharif University of Technology Hassani, Ali (Author) ; Saghafi, Fariborz (Supervisor)

Abstract

Recent developments in space industry and the great tendency for definition of efficient, precise and low cost missions are the main reasons for the growing interest in satellites formation flight. Regarding the aforementioned, the study of the multiple satellite control methods is the subject of the present project. In this project, the governing equations of motion of satellite formation flight are developed. Based on this development, it is shown that the satellite linear equations of motion like many other linear system presentations, can not sufficiently model the real system. Therefore, some of the most famous uncertainties in space dynamics such as semimajor axis and eccentricity...

Development of a Distributed Algorithm for Flocking of Non-Holonomic Aerial Agents

, M.Sc. Thesis Sharif University of Technology Soleymani, Touraj (Author) ; Saghafi, Fariborz (Supervisor)

Abstract

The goal of this project is the development of a control algorithm for a flock of non-holonomic aerial agents. For this purpose,the swarm architecture having some unique features such as robustness, flexibility, and scalability is utilized. Swarm is defined as a group of simple agents having local interactions between themselves and the environmentwhich shows an unpredictable emergent behavior.Behavior based control which is inspired from the animal behaviors is employed to control the swarm of mobile agents. Accordingly, the necessary behaviors which are distance adjustment, velocity agreement, and virtual leader tracking together with a fuzzy coordinator are designed. In this study, in...

Optical Flow Based Flight of a Small Fixed-Wing Aircraft in Ideal Urban Environments

, Ph.D. Dissertation Sharif University of Technology Rezaei, Mahdi (Author) ; Saghafi, Fariborz (Supervisor)

Abstract

This thesis represents the obstacle avoidance of a fixed-wing small aircraft using optical flow information of cameras mounted on the aircraft. The thesis consists of two main sections. In section one, the ideal optical flow has been simulated based on the camera model, complete six DOF of flight equations, and the geometry of the environment. An analytical formula has been derived to relate the obstacle detection distance to the maneuverability of the aircraft. Having the obstacle detection distance, the control and navigation algorithms have been developed to achieve a collision-free flight for the aircraft in urban canyons and junctions. The effect of some parameters such as approach...

Flight Performance and Maneuverability Enhancement of a Twin Engine Fighter Aircraft Using Integrated Thrust-Vector and Aerodynamic controls

, M.Sc. Thesis Sharif University of Technology Mazinani, Morteza (Author) ; Saghafi, Fariborz (Supervisor)

Abstract

In this thesis, maneuverability enhancement of a given twin engine fighter aircraft with integrated thrust-vector and conventional aerodynamic control surfaces havebeen studied. For this purpose a nonlinear 6DOF simulation program base on a near exact mathematical model has been prepared for the aircraft, and then a thrust vectoring system for producing moments about three body axes, like that used in F/A-18, has been added to the simulation. The control method that is employed to control the aircraft in simulation environment is based on Nonlinear Dynamic Inversion (NDI). Finally the Velocity Vector Roll (VVR) maneuver has been considered as an example tostudymaneuverability enhacement. It...

Robust Nonlinear Control of a Jet Tail-sitter UAV in Hovering Flight Phase

, M.Sc. Thesis Sharif University of Technology Sarafraz, Yasin (Author) ; Saghafi, Fariborz (Supervisor)

Abstract

In this thesis, the theory of robust control is applied to design a controller for the longitudinal dynamics of a tail-sitter jet engine unmanned aerial vehicle. The engine thrust deflection is considered as the input controller of the system. The aircraft dynamical model is developed based on the assumption of no aerodynamic loads in low speed flight associated with the hovering condition. The controller is primarily designed using both classical and modern control techniques. Then and synthesis approaches are applied to design the robust controller. The results obtained from different approaches are compared. It is shown that the robust controller techniques are more stable and robust...

Development of a Vision-Based Position and Attitude Estimation Algorithm for Close Proximity Operation of Small Satellite

, M.Sc. Thesis Sharif University of Technology Pasand, Milad (Author) ; Saghafi, Fariborz (Supervisor)

Abstract

One of the key technologies in the future space missions is the formation flight of small satellites. Currently, widespread research in this field is being carried out and remarkable developments have been achieved. In the mentioned laboratory researches, satellite navigation is performed by conventional sensors like infrared and ultrasonic. Both of these sensors are of active type and energy consuming. Also, use of the ultrasonic sensors is impractical in space missions (due to vacuum condition). Therefore, as an alternative for space missions, visual sensors are good candidates. The main goal of this research is to present a method for the relative navigation in proximity operations in an...

Numerical Optimization and Parametric Study of Cooperative Salvo Attack Using Particle Swarm Optimization Algorithm

, M.Sc. Thesis Sharif University of Technology Shahadati, Mohammad (Author) ; Saghafi, Fariborz (Supervisor)

Abstract

In this research work, several guidance laws have been utilized and validated, considering the contraints on the missslie seeker angle and maximum acceleration, in order to simultaneously intercept the so-called Close-in Weapon System (CIWS) by multiple missiles. First of all, the existing guidance laws for salvo-attack are reveiwed. Then, a simulation program has been developed and validated for the misslie and CIWS as a five and two degrees of freedom systems, respectively. Optimization of the system is then carried out by the method of Particle Swarm Optimization, considering the given constraints. In the next step, for the improvement of the optimized guidance law, paramertic study has...

Machine-Vision-Based Auotomatic Landing of Unmanned Helicopter

, M.Sc. Thesis Sharif University of Technology Nasirian, Behnam (Author) ; Saghafi, Fariborz (Supervisor)

Abstract

In this project an algorithm is designed for automatic landing of unmanned helicopter on a pad moving with six degrees of freedom. The designed controller is based on state dependent riccati equations (SDRE).by developing nonlinear mathematical model of helicopter and then converting this model to state dependent coefficient (SDC) form. A nonlinear compensator is added to controller to compensate effect of some nonlinear terms of model that are not able to translate and then state dependent riccati equations are solved.
The relative pose-estimation of landing pad is based on vision. Corner detection algorithm is used to identify and detect features by processing of image taken from...

Application of Nonlinear System Identification Techniques in the Modeling of Agile Fighter Aircraft Dynamics

, Ph.D. Dissertation Sharif University of Technology Roudbari, Alireza (Author) ; Saghafi, Fariborz (Supervisor)

Abstract

Modeling and simulation are widely used as essential tools to predict and analyze complex systems in various scientific and engineering fields. For an aerospace system such as aircraft, mathematical models are useful used to carry out such tasks as dynamic analysis, autopilot development and combination of flight control laws, hazardous behaviors prediction, the controller design and validation, the study of the handling qualities, or the implementing simulators used for training pilots and many other tasks. In general, the aircraft flight dynamics is a nonlinear and coupled system whose dynamic modeling, in addition to pilot control inputs, depends on flight conditions (i.e., Mach and...

Experimental Investigation of Microjet Engine Anomaly Detection Based on ANN Data Clustering Analysis

, M.Sc. Thesis Sharif University of Technology Khodadadi, Mahyar (Author) ; Saghafi, Fariborz (Supervisor)

Abstract

In this study, the possibility of detecting known and unknown anomalies in a micro jet engine is evaluated. the proposed method is neural network and clustering analysis. The process consists of two main parts, first part is experimental abnormal behavior simulation and second part is validation of proposed detection method. In the first part a micro jet engine (Olympuse HP) were used and we created pre-designed errors in engine normal behavior to record significant changes in its performance. Recorded outputs consist of six different variables: RPM, Exhaust gas temperature, Throttle command, Fuel pump voltage, Thrust and Fuel weight. In the second part, for analyzing data, we used...

Self-Reconfiguration & Autonomous Algorithm for Spacecraft Formation Flight Using Virtual Structure Approach

, M.Sc. Thesis Sharif University of Technology Sharifian, Shakib (Author) ; Saghafi, Fariborz (Supervisor)

Abstract

One of the most important technologies in space missions is capability of moving satellites together with a predefined structure (virtual structure). This structure can reconfigure itself to any desired space mission and it is known as reconfiguration maneuver, in this maneuver all of the satellites have to follow needed virtual structure from any initial configuration to any desired second composition. In available virtual structure methods, there are a lot of limitations in maneuver because of algorithm constraints, in this project we try to extend available algorithm in virtual structure method and reach an algorithm which can start from any initial condition and complete the maneuver in...

Dynamic Modeling of a Quadrotor UAV Transporting a Variable Mass Payload Suspended by Continuous Flexible Cable

, M.Sc. Thesis Sharif University of Technology Baha, Mirshams (Author) ; Saghafi, Fariborz (Supervisor)

Abstract

Quadrotors are one of the most popular unmanned aerial vehicle (UAVs) that has been subject of extensive research in recent years. One of the most important applications of these aerial vehicles is transporting a cable-suspended payload from one point to another. The major challenge in modeling of this system is dynamic coupling which exist between all components of the system i.e. payload, cable and quadrotor. The purpose of this research is mathematical modeling and dynamic analysis of the system in presence of this dynamic coupling and considering the effects of cable's flexibility. In this regard, it is assumed that the payload has variable mass. In this thesis, in the first step, by...

Dynamic Modelling of Multiple Quadrotor Suspended Load Transporting System with Variable Center of Mass via Flexible Cables

, M.Sc. Thesis Sharif University of Technology Latifi, Alireza (Author) ; Saghafi, Fariborz (Supervisor)

Abstract

Using unmanned aerial vehicles in aerial payload carrying leads many changes requiring significant study and research. In recent years, there has been considerable maturation in Micro Aerial Vehicles (MAV) developement especially quadcopters. In addition to the endurance restriction, considerations on volume and weight that can be carried, and safety issues are also obstacles to the development of unmanned aerial payload carrying in urban environments. One of the ways to make a quadcopter more agile while carrying a load is to hang the cargo from the quadcopter via a cable. In this way, it is possible that quadcopters carry the cargo in a cooperative way, which if properly arranged,...