Sharif Digital Repository

The produced crude oil from the petroleum reservoirs usually has a value of brine (water and salt) this matter can be caused the corrosion of refinery equipment. The large part of this brine creates a stable emulsion with oil, that it couldn't be separated easily. For separation and demulsification of this emulsion, some chemical, mechanical, thermal and electrical methods can be executed. In chemical method, demulsifier materials can be added to water-in-oil emulsion. Different parameters such as properties of oil, type and concentration of demulsifiers, volume factor of water and etc., can affect the efficiency of water-in-oil emulsion separation. In this study, emulsification mechanism,... 

In this thesis, a dynamic model of the biomimetic robotic fish with a flexible tail is developed. In this model, the oscillating frequency of the tail controls the forward velocity, and the body spline offset parameter controls the heading angle. The robotic fish were divided to two parts: a rigid body, and a flexible tail. The rigid body includes the head and the electrical and mechanical equipment. The bond graph model was developed and the numerical values were extracted from constructed robotic fish have also been hydrodynamically analyzed. Simulation results were quantitatively compared and verified with Matlab Simmechanics simulations. These simulations described the lateral movement... 

This thesis contributes two separate predictive direct torque control methods; based on hysteresis and fuzzy logic for Brushless Doubly Fed Induction Machine (BDFM). Initially Chapter 1, focuses on BDFM history and concept of this machine and after that a short review about the development of BDFM and the Field Oriented Control will be studied. Chapter 2 introduces the d-q-0 state transformation matrix, dynamic equation of BDFM and represents its steady-state equivalent. Furthermore, in this chapter the bond graph model of BDFM is studied and via distinguishing all energy ports the bond graph model of this motor is introduced and validated, finally the result of this model is compared with... 

Gas turbine engine control is a demanding task that requires the regulation of the thrust as well as the satisfaction of the limitations such as engine aerodynamic instability, over temperature and over speed. Fuzzy logic is an attractive technique for the control of poor understood unmodeled, or complex systems especially where the experience of human operators is available to provide qualitative rules. In such cases, it has been found that control decisions can be made on the basis of linguistic measures or fuzzy algorithms. The controller that is designed on the basis of this theory is called fuzzy logic controller. The main objective of this thesis is hardware implementation of fuzzy... 

Mobile robots are increasingly being used to perform tasks in unknown environments. The potential of robots to undertake such tasks lies in their ability to intelligently and efficiently locate and interact with objects in their environment. My research focuses on developing algorithms to navigate mobile robots in a partially known environment observed by an overhead camera. The environment consists of stationary and dynamic obstacles and a moving target. The aim of the robot is to select avoidance maneuvers to avoid the dynamic obstacles while approaching the target. The core of the navigation algorithm is based on the velocity obstacle avoidance method and the guidance-based tracking... 

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... 

In this thesis, in order to improve the performance of the mobile robot navigation, a Fuzzy approach is used for making a safe path in the cluttered environment with hurdles in the work space of the robot. To this end, based on data collected from instantaneous location of the robot and location of the robot, heuristic rules are extracted. Also, in order to obtain optimal data fusion of the sensors, Kalman filter is used to localize the robot. In this regards, by using the kinematics of the robot and supposing the white noise in the process and measurements, the position and orientation of the mobile robot are estimated in a real-time and adaptive manner  

Weed management is the important issue in agriculture. Using herbicides is one of the strategies to control weed. But using huge amount of herbicides are destructive for environment. Smart spraying system is an impressive solution for this problem. This system detects weeds and sprays just them instead of spraying overall field. In this thesis a new method for plant detection is presented by using Lab color space. We determine the type of plants (broadleaf/grass) to spray specific herbicides onto specific type of plant. One feature of grass plants (the parallel edges of leaf) is used to detect grass plants. A convolutional neural network with four layers and fuzzy logic are used to separate... 

Control of parallel robots continues to be a challenging research topic. The structural variety of such robots dictated by the application and function makes such control strategies even more unique. As these robots often require nonlinear control schemes, such research has been focused towards two general controlling computational intelligent methods, namely adaptive (and optimal) control and artificial intelligence (e.g. fuzzy and Neural Net) based control. This study considers Neural Net (NNs) and fuzzy control method in order to propose a control scheme for a newly introduced 5-link parallel robot which has 3 degrees of freedom operating in a single plane environment (i.e. two... 

Approximate Agreement (AA) is one of the most important issues in distributed networks in which non-faulty processes execute a voting algorithm to reach the values that are very close to each other. AA for Partially Connected Networks (PCNs) is very limited because a node may not have a complete view of the whole network which makes it difficult to reach the convergence. This research proposes a convergent Fuzzy algorithm for synchronous distributed networks in the presence of faulty or Byzantine processes. When each node receives a new value from its neighbors,it runs the convergent Fuzzy algorithm. If the received value is not in the expected range of values, the processor can discard the... 

Mental disorders are very common nowadays and affect a person’s everyday life, as well as the lives of other people around him/her. According to the World Health Organization, major depressive disorder (MDD) is considered as the fourth main cause of death and premature weakness in the whole world. Information Technology (IT) could be used to diagnose the people who are affected by the mental disorders as well as reduce their effects. As clinical decision making inherently requires reasoning under uncertainty, fuzzy logic is a suitable technique for dealing with this partial evidence. The fuzzy logic is the science of reasoning; thinking and inference that recognizes and uses the real world... 

Airports are critical connectors in the air transportation operational system. In order to meet their operational, economic and social obligations in a very volatile environment, airports need to embrace change rather than resist it. Long-term airport planning has become a complex issue due to the constant growth in air traffic demand. In this context, the thesis puts forward an innovative approach to planning and decision making for various component of airport.in this has been used fuzzy logic decision making method to develop airport in all respect in order to plan balanced growth. Top airports are successful experience in airport expansion planning which can be pattern for other airports... 

Today, a lot of efforts have been done in order to commercialize space travels. Spacecrafts have a lot of components and producing each of them spends high costs. Components such as propellant tanks and boosters are multi segment and are released simultaneously and therefore it is economically feasible to recover them. Due to Parafoil ability in low-cost, soft (no damage to the cargo) and accurate landing, it is gradually replacing parachute. Parafoil can fly long distances after being released, so its landing point could be determined. The aim of the study is to evaluate this scenario in which some segments of launch vehicle (e.g. booster) that are equipped with Parafoil expand their... 

In this research, a Ground-to-Ground axisymmetric flying vehicle is studied. In this flying vehicle the warhead is replaced by a nose having simple and cheap guidance and control. Commonly such systems include axial rotation to increase stability, which results in the malfunction of the added seekers. In this research, to overcome this problem, the rotation of the vehicle’s forward part is controlled by fuzzy control method, from the beginning of the fly. In addition, a strapdown seeker, which has high accuracy and low cost is used. This provides the system with employing Integrated Guidance and Control (IGC). The IGC, used in this research is based on fuzzy logic, which directly determines... 

The purpose of this thesis is to present a novel approach in Terrain Following/Terrain Avoidance (TF/TA) flight using Fuzzy Logic. The fuzzy logic can decide where and how the aircraft needs to change its altitude and/or heading angle. The method due to its fast decision making algorithms would be useful for on-line operation. It could also help design trajectories in an off-line manner. To achieve the above goal, the method effectively incorporates the dynamics of the aircraft and could handle tough terrains in terms of shape and peculiarities. The mathematical method basically, uses a special relationship among existing slope and slope derivative of the terrain together with aircraft... 

In this thesis, fuzzy logic is used to suggest a simple algorithm in guidance and control suitable for upper stage decoupler transfer with finite and continuous thrust. It is attempted to improve injection accuracy utilizing classic guidance and control methods and fuzzy logic, while unpredictable errors exist. Orbital perturbations, uncertainties in thrust vector, and initial injection errors in parking orbit, are considered in order to actualize results. In this research, Lambert guidance, velocity to be gained, and fuzzy logics are used for upper stage guidance. Fuzzy-PD control is designed and applied into the upper stage. Final results show acceptable position errors and suitable fuel... 

An automatic air traffic controller system is designed in this research. The major goal is to aid the human controller in decision making at real air traffic control situations. The air traffic system is modeled by queuing theory. Since respond rapidity is very important in air traffic control, so the fuzzy logic is utilized to construct a rule-base. This rule-base determines optimum policies while considering the operational matters, minimum separation distance requirements, air traffic controller techniques, and work-load. This project is an initial design for air traffic automation system which considers scheduling optimality as well as delay reduction. The case study is done on Denver... 

Due to the long physical distance between the users and the cloud data centers, the idea of considering fog layer was established to bring computations closer to the edge of the network, and provide a solution for latency-sensitive applications. In such applications, the tasks are offloaded, and assigned to the available virtual machines in the cloud or fog layers, which directly contribute to Quality of Service (QoS) requirements. Among various applications, the real-time applications require their tasks to finish before their deadlines. Therefore, an assignment or a scheduling algorithm is needed to assign incoming tasks to virtual machines in cloud or fog layer. Most of the research on... 

Three dimensional or vertical integration is a new way of increasing the performance and expanding the capacities of modern integrated circuits. Using this technology, 3D Networks on Chip has been proposed as one of the novel research fields and has been receiving a lot of attention. 3D Networks on chip have a lot of benefits such as capability of large scale integration, increasing the density of elements on chip and expanding the dimensions of chips. Large scale integration and increasing density of elements will cause more consumption of energy. This more energy consumption will cause high temperature in chips. Although high temperature has been managed in 2D networks, but necessity of... 

Performance of civil infrastructures, such as high-rise buildings, bridges, tunnels, offshore platforms and other structures may be critically influenced by existence of structural damages or even lead to devastating consequences. Structural Health Monitoring(SHM) and damage detection denotes the ability to monitor the performance of structure, detect and assess any damage at the earliest stage in order to reduce the life-cycle cost of structure and improve its reliability and safety. Generally, damage is defined as some changes in the physical properties of a structure, such as stiffness matrix. On the other hand, presence of damage causes changes in structural dynamic characteristics, such...