Sharif Digital Repository

In today’s world, people’s tendency to use their own vehicles is relatively high since private cars provide more convenience, better safety, and better time management than public transportation, but cause more traffic in the streets. Ride-sharing is one of the management tools that has attracted a lot of attention in recent years to mitigate the traffic congestion. Also, electric vehicles are used for public transportation in many parts of the world to achieve a sustainable environment. In this study, we assume that passengers’ origin, destination, and preferred time windows for pick-up and drop-off are known in advance. The aim of the study is to determine the sequence of visiting travel... 

PRP is a combination of two classic problems. First one is the lot-sizing and the second one is vehicle’s routing which have been studied for more than fifty years. The prp is solved in attempt to jointly optimize production, inventory, distribution, routing decision and as a result, it is a inventory-routing problem as a whole. Despite the fact that prp involves a complex instructor, both universities and industries have been so eager to this problem since last decade. In this thesis an integrated assessment of PRP and various technics for solving the problem have been discussed. Moreover, taking into account the structure, hypothesis, and the constraints of the problem, a... 

In today’s industrial world production is considered as a competitive weapon. This has caused many companies active in this field to move towards creating competitive advantage to reduce costs of design, construction and increase production. In particular molding as one of the main industries is among the most economical technological resources of each country. About 50 to 70 percent of the price of a production operation is spent of the strip of sheet by pressing; thus the proper design of a strip of sheet has a great impact on the mold design. Today, in most sectors of the industry there is a need for cutting and packaging of products and form molding and glass cutting to fitting the... 

Railway managers have strong economic incentive to minimize the cost of track maintenance in order to conserve safety standards and provide adequate service levels for train operators. The main object of this study is to provide a method for railway repairing and maintaining management and improve previous researchs.
In this study, a cumulative damage model based upon a nonhomogeneous Markov process is developed to model track deterioration. The maintenance of deteriorating facilities can be a great challenge because the process of deteriorating has random features for some facilities.
The genetic algorithm is used to find the optimal repair for each possible track state in the... 

Determining the best location for new wells is a complex problem that depends on reservoir and fluid properties, well and surface equipment specifications, and economic criteria. Various approaches have been proposed for this problem. Among those, direct optimization using the simulator as the evaluation function, although accurate, is in most cases infeasible due to the number of simulations required. This study proposes a hybrid optimization technique (HGA) based on the genetic algorithm (GA) with helper functions based on the polytope algorithm and the neural network. Hybridization of the GA with these helper methods introduces hill-climbing into the stochastic search and also makes use... 

In this work, we propose a metamodel-based simulation optimization algorithm using a novel hybrid sequential experimental design. The algorithm starts with a metamodel construction phase in which at each stage, a sequential experimental design is used to select a new sample point from the search space using a hybrid exploration-exploitation search strategy. Based on the available design points at each stage, a metamodel is constructed using Artificial Neural Network (ANN) and Kriging interpolation techniques. The resulting metamodel is then used in the optimization process to evaluate new solutions. We use Imperialist Competitive Algorithm (ICA) which is a powerful population-based... 

Concerns like fuel cost, pollution and global warming has made it necessary to look for new energy solutions. Renewable and alternative energies have proven themselves to be helpful in this matter. Renewable energy(RE) is the energy that comes from natural resources such as sunlight, wind, rain, tides, waves and geothermal heat, which are naturally replenished at a constant rate. Renewable energies are environmentally friendly, not cheap at the beginning but naturally available in a constant rate and wide spread, unlike fossil fuels that are localized in the limited places. In this thesis in order to generate environmental friendly power we consider two renewable energy resources: wind and... 

Modular Robots are group of robots which are made of small components called modules. The advantage of these robots to others is their ability to change physical configuration. Using of these robots in configuration changing due to environmental conditions is popular. While, reconfiguration is one of the most important features in modular robot, it’s the most important concern too. Path planning problem is one of the important problems in robotics .So far, most of presented path planning methods and algorithms are based on fixed-structure and they had little attention to path planning and configuration changing, simultaneously. In this thesis, the Genetic Algorithm is used to find path and... 

In this study, the attitude control of an under-actuated satellite has been investigated. The investigated satellite uses reaction wheels for attitude control. For having full controllability of a satellite attitude, at least three reaction wheels are required. However, due to the high failure rate of reaction wheels, in this study assumed the satellite has two perpendicular reaction wheels, which causes the satellite to be under-actuated. The path planning method is used for controlling the satellite, which is an offline method. In the beginning, tries to define the control input of the satellite in term of limited parameters with different methods. In this regard, the control input is... 

The idea of using groups of simple autonomous robots instead of one or limited number of very sophisticated robots is inspired by flocking behaviors of animals. Distributed control structures and artificial swarming have attracted lots of studies in robotics. There are many applications for robotic swarms in which members are very simple robots with low communication capabilities. These robots communicate only within very limited distances. In this thesis, a homogenous robotic swarm with at least two robots is assumed. Swarm robots are considered to be dimensionless with no time delay, which is a normal assumption in this field of studies. Robots move in planar space and their behaviors are... 

• Brachiation robot is a kind of under-actuated robots. A brachiating robot is a type of a mobile arm that is capable of moving from branch to branch similar to a long-armed ape. The purpose of this thesis is control of a two link Brachiation robot. The purpose of this thesis is control of a two link Brachiation robot using neural network and geometry control. For this purpose a genetic algorithm based training Neural Network is used to produce a suitable path for the second link of the robot and then using input-output linearization method, the second link is controlled to follow the path. The simulations shows that the Nero Controller designed in this thesis is suitable. The controller can... 

Today, cancer mortality is one of the most important problems, even considering the scientific advances that offer more effective solutions to treat some diseases, providing a way to prevent and treat this disease is one of the most important issues that engineers have considered. This is achieved by designing a controller to minimize the size of the cancer tumor population, increase healthy cells, optimize treatment time, and drug dose.To achieve this goal, pharmacokinetic, pharmacodynamic, tumor growth, and healthy cell growth models, and mathematical models for subsystems that affect tumor growth, such as the angiogenic system, have been studied to develop a single mathematical model. In... 

During the turning operation, the interaction of the metal cutting process and machine tool causes a dynamic instability called self-excited vibration or chatter. Limited productivity rate, decrease in tool life, poor surface quality and noisy workplace are some adverse effects of the chatter vibration. Chatter suppression in machining processes results in more material removal rate, high precision and surface quality. In this thesis, two control strategies are developed to suppress chatter vibration in turning process including a worn tool. A single degree of freedom model of the turning process including tool wear is briefly described. In the first stage, a sinusoidal spindle speed... 

Existence of time delay and interactions of control loops make control of multivariable delayed systems more difficult، therefore control of these systems is important. In this project a control scheme based on prediction of process output has been proposed. Traditional PI controllers are used in the control structure and controller parameters are tuned by genetic algorithm. Unlike the Smith predictor based methods، which become internally unstable when applied to unstable plants، unstable delayed multivariable systems can be handled by proposed method. It can also be applied to stochastic systems. The robust version of the control scheme has also been designed. Effectiveness of the proposed... 

Today, the use of controllable swimmer micro-robots has expanded from micro to macro-scale dimensions due to their many applications. These robots, as a result of their small size and dimensions, have the ability to access limited and complex environments. Considering the various applications of such swimmers, it can be said that in addition to the necessity of well designing and implementation, their maneuverability and controllability are among the most important research areas on these swimmers. Regarding the dimensions and technologies needed for these robots, various methods for designing and implementing them are suggested, which are mostly inspired by the nature of microorganisms. In... 

In batch cooling crystallization, the crucial control problem is to design a temperature trajectory which produces a desired crystal size distribution. Here, a completely different solution is presented. Designing model-based controller for crystallizer has two steps; first step is determining optimal temperature trajectory which is some kind of feedforward control, second step is adding feedback controller (with manipulated variable of jacket temperature or cooling flow) to track the set-point (determined in first step) and rejecting possible disturbances. Traditionally, determining optimal temperature of crystallizer is done by using calculus of variations of distributed system. In this... 

Selection of the most appropriate control configuration for two point control strategy in a distillation column is a challenging problem. In the present work, three control configurations namely , and , have been employed to control a high purity distillation column separating the binary mixture of Benzene-Toluene. A simple linear model for the process has been derived via a system identification technique. The uncertainty and performance weights have been defined and have been utilized to design a robust controller based on the μ-synthesis approach. The genetic algorithm is employed and the peak value of μ is minimized in order to obtain appropriate PI controller parameters for each... 

This study presents the application of the doubly fed induction generator (DFIG) to reduce the frequency deviation and improve frequency of a power system. This has been done by proposing a wind turbine model and a new fuzzy controller. The fuzzy controller has been suggested to change the speed of the wind turbine rotor and modify the impacts of wind speed fluctuations on the output power. The fuzzy controller parameters are optimized using the genetic algorithm (GA) to achieve the appropriate transient response. A smart controller is combined with fuzzy controller to optimize the usage of wind turbine’s kinetic energy. Furthermore, the DFIG with the proposed controller participates in the... 

Reducing energy consumption is one of the challenges facing wireless sensor networks with many solutions introduced for them with each having advantages and disadvantages. Some of the solutions introduced are based on using movable sinks. In this project, we attempt at proposing a place for the establishment of sinks using genetic algorithm that can reduce energy consumption in the net knots and increase the net life. This work should be done after reviewing the results of past researches and introduced methods. We will analyze the practicality of the proposed model using simulation and will show their advantages over the previous mentioned methods  

This paper is a study on control of vibration of plate subjected to random vibration loading using magnetorheological (MR) dampers. Some key issues, i.e. model reduction, modeling of the MR dampers and their applications in vibration control of plates, are addressed in this work. MR dampers are semi-active devices that use MR fluids to produce a controllable damping with low power requirement. In this paper, first, a model reduction method for preparing a reduce order model (ROM) is presented. The method uses an optimal model truncation method which in it the ROM to be constructed such that it will provide the same frequency response characteristics as the original full model within the...