Sharif Digital Repository

The aim of this project is designing and implementation of a BCI for interacting with virtual environments. BCI is an interface between brain and computer that connect those by translating brain signals into understandable instruction for computer. There are different ways to generate brain states for classification in BCI technology. One of those, is based on motor imagery (MI). In this project, we used motor imagery of left hand, right hand and foot. subject training in this kind of BCI (MI-based BCI) is very vital. in order to speed up subject training period and consequently enhance the separability of brain states, computer graphics and virtual environments are used to excite the... 

In systems possessing spatial or dynamical symmetry breaking, Brownian motion combined with unbiased external input signals, deterministic and random alike, can assist directed motion of particles at nanoscale. “Brownian motors” are devices by whi thermally or extrinsically activated processes are controlled and used to generate directed motion in space. Rectification devices involving asymmetric substrates are termed ratets and if the potential priodically turns on and off in time, it is called “Pulsated Ratet.“ In this resear net current of particles in 2D pulsated asymmetric potential landscapes is surveyed theoretically and by
Monte Carlo method simulation  

Constantly rising fuel prices and environmental consciousness have caused alternative transport solutions to be considered.Recently, batteries and electric vehicle industries have developed to become a reasonable alternative for gasoline powered cars. Plug-In hybrid electric vehicles could be connected to the electrical grid to be recharged. To ease the charging process, one solution could use an on-board charger to charge the electric vehicle. This charger should be able to be connected to a conventional outlet for convenience reasons and moreover, it should be a grid friendly charger in order not to pollute the electrical network. After studying the introduced structures for electric... 

Mass production of Plug-in Hybrid Electric Vehicle (PHEV) and requests for long trip capability necessisated development of fast charging station that can charge PHEV in a feuling time of a conventional vehicle. Fast charging station design requires a systematic approach to consider various related issues.
The aim of this thesis is to design a fast charging station. First, the daly demand for PHEV charging is modeled considering number and type of PHEV as well as level and pattern of daily driving of PHEV. Uncertainty in daily driving and in PHEV state of charge in the start of charging are also considered in modeling charging demand. An approach, then, is proposed for optimal design of... 

The brushless DC Limited-Angle Torque Motor (LATM) has been widely used in area of aerospace equipment, robot drives, optical scanning systems and any drive systems that require limited motion, ranging from the simple ON-OFF servo valves to the accurate tracking of a reference signal. This paper presents the optimum design procedures of a brushless direct current limited-angle torque motor. According to a request from industry, a two-pole torque motor with a toroidal armature winding was designed based on analysis of magnetic equivalent circuit of motor structure, and using selected ferromagnetic material and rare-earth permanent magnets (PM). To select the best design solution and optimize... 

In the present thesis, intracellular fluid flows have investigated for study cell motions. It is due to firmly relation between the cell motion and these flows. Generally, the cell firstly adheres to a surface, then, moves forward with the effects of the internal fluid flows. In this study, the cell structure is invided to two general parts; the front part of the cell and the cell body. The front part of the cell plays a essential roles in the cell motion, however, the cell body is considered as a extra cargo that is carried by the front of the cell. Therefor, in the present modellings, the front part is only considered. Here, using four different models for the front part of the cell, many... 

Compact linear accelerator is equipped with a single fixed motorized wedge that produces different wedge angles by combining an open and a wedged field in the appropriate proportions.
In this work, the required data for the Treatment Planning System, TPS were generated for utilizing Compact motorized wedge, MW and was verified by dosimetry. To verify MW, the accumulated wedge profiles at a depth of 10 cm for different wedge angles were measured using 2-D Profiler and were calculated the wedge angles using an analytical formula. The validity of effective wedge angles 2-D Profiler has been done by determining the wedge angles in accordance with ICRU-24 for compact MW and Telecobalt... 

Controlling four legged robots is a complex challenge. The previous works in this field can be divided into two main categories, Analytic method and intelligence method. The analytic method is based on extracting the motion equations of the robot, but in most cases these equations are so complicated, and their implementation is difficult. Another method is intelligence method, which is based on learning algorithms. Despite the improvements in walking robots field, still their walking quality is far from human and animal walking. Researchers believe that this advantage is the result of the learning ability in animals and human. Therefore in this paper the human learning ability is used to... 

The existence of motor synergies in motor system as a tool for reducing degrees of freedom has been always debated. In the last two decades some experiments in vertebrates show the existence of motor primitives in spinal cord. In additional by recording electromyogram from frog some regular patterns have been shown. Recently, a motor coordination model based on stochastic optimal feedback control has extracted synergies by mathematical formulation. In addition, according to this model synergies are the optimal solution of the problem and not for simplifying it. However, this model is investigated in linear dynamics. In this thesis, first, an inverse method for extracting synergies is... 

Constantly rising fossil fuel consumption and the resulting air pollutants have caused hybrid electric vehicles to be considered as the most efficient mid-term solution for decreasing problems resulting from environmental pollutions and rising fuel prices. Various types of hybrid electric vehicles and power transmission schemes are studied in this thesis. Electric motors utilized in electric vehicles and hybrid electric vehicles such as induction motor, brushless permanent magnet motor, DC motor and switched reluctance motors are investigated based on previous studies and researches, and are compared for all basic criteria. For completing the comparison procedure and selecting the most... 

Dependence of some magnetic properties such as core loss and permeability on temper rolling was studied in this thesis. It is shown that with a proper temper rolling sharper textures are obtained in the electrical steel and the magnetic properties in the longitudinal and traverse directions are improved. By texture analysis, it is shown that because of temper rolling, shear strain on the surface of the sheet is the main factor for abnormal grain growth and shear texture formation on the surface. The result of formation of this texture is enhancement of the {100} intensity and reduction of the {111} intensity, leading to the improvement of the permeability. Temper rolling is always... 

Recently, the computational algorithms underlying in the nervous system of vertebrates have been attracting scientists and engineers. Therefore, a number of artificial learning methods are proposed for mathematical interpretation of these algorithms. In this thesis, by investigating the latest findings about the nervous system, and the motor system in particular, a novel machine learning scheme inspired by human motor learning is proposed. Basic theoretical aspects of this method in conjunction with some of state-of-theart artificial learning methods are discussed. Finally, this method is evaluated in a variety of engineering problems ranging from curve fitting and function approximation to... 

Motor imagery causes Event related Synchronization/Desynchronization (ERS/ERD) in Electroencephalogram (EEG) signal. These potentials can be used as an input for a Brain Computer Interface (BCI) system. To do so, it is necessary for these inputs to be correctly classified. The quality of classification is severely affected by the features extracted. Common Spatial Patterns (CSP) algorithm is often used for this task. Some of this method disadvantages are neglecting non-stationary properties of EEG signal and its proneness to overfitting. Additionally, its success is highly dependent on the frequency band that the algorithm is performed in. The most suitable sub band is interchangeable... 

The goal of this research is to solve the traffic assignment of electric vehicles with considering trip chains. Limited driving range of electric vehicles is considered as one the most important obstacles for the development of these cars. The worry that the battery will run out of power before the destination is an important issue regarding the electric cars and people usually experience it more in trip chains. In this research, a complementary model and a linearization method is used for traffic assignment. In determining shortest paths in the traffic assignment, in addition to considering the travel time and the distance limit, the constraint of passing through activity nodes is... 

During the past decade the ever increasing volume of greenhouse gases due to fossil fuels consumption have made humans to seek for alternative, non-polluting fuels as an effective strategy to reduce pollution and prevent environmental issues thereof. Electric cars are today known as one of the most effective solutions for this purpose. Of course, transition from gasoline-powered cars to electric cars in a wide scale is not technically possible in short term due to technological and infrastructural limitations. As a result, this lengthy process would lead to emergence of a combinational transportation system including both gas and electric-powered vehicles. The major differences between these... 

Energy management in vehicles is ann important issue, because it can significantly influence the performance of the vehicles and component sizing., Although the bbatteries have been widely used in electric vehicles (EVs), However the large current impact of battery cycle life is still a difficult problem that remains to be resolved and because of that, Hybrid Electric Vehicles (HEVs) areis the way that allows to to achievinge the advantages of both engines.Hybrid cars uses both an electric motor and internal combustion engine (ICE) used together, so, itwhich can benefit from the advantages of both engine types. ImprovImprovement ofing energy management in (HEVs) can providedeliver important... 

Most propulsion systems use nozzles to increase the velocity of exhaust gas. Therefore, the efficiency of nozzles is important. Losses due to geometry and physical phenomena inside the nozzle define this efficiency. The length and divergence angle of the nozzle, the throat diameter, the Reynolds number, and the specifications and the combinations of fuel have a direct impact on these losses. Solid propellant rockets are widely used and today optimization of rockets is most noticeable. On the other hand, in different phases of design and optimization, empirical experiments are necessary, which are costly in real dimensions. The use of laboratory motors with specific considerations decrease... 

In this project optimization of the assembly line balancing of Pride Motor is considered. The technical specification and limitizations as well as the production process of the product of this line is studied and documented through opc-fpc diagram, and assembly charts. Differential time study procedures are studied and the stop watch approach is selected to calculate the normal time of each operation. Through evaluation of line bottle necks the most important stations are reconsidered and have been pointed out.Considering operations procedure, priorities of the operations in the line, number of operations in each station, and requirements of investments for the changes, a solution for... 

There are two ways for quality control testing of power transmission systems in various industries. A method of testing the specific positions of power transmission, and final testing (Automotive road tests), respectively. In various stages of design, manufacturing and quality control components, power transmission systems, require detailed information on the performance of parts. It's a special place for each transmission experiment designed and manufactured. Gearbox as an important component of the transmission of this issue is no exception. Magnetic gearbox has a new generation of power transmission systems in the last decade of the optimization is presented. In recent years, several... 

The perpuse of this thesis is to design and fabricate a laboratory one degree of freedom stable platform under turbulences by model-based design method. To do this, different parts of the system were first modeled in the Solidworks software and then fabricated with various tools. With proper assembly of electronic and mechanical components, the original body of the system was created. Then, the controller motor with a stable platform which is attached to it was modeled and simulated in MATLAB software. Then, the parameters of the equations were calculated using standard identification tests and TCACS optimization algorithm. One of the challenges of this thesis is the malfunction of the...