Sharif Digital Repository

Many future space missions, will require a high level of autonomy to service, repair, refuel, reconfigure satellites. As we know there is no project that has demonstrated an actual online pathpelanning for a terminal rendezvous phase in docking maneuver, for an uncooperative tumbling target. Particularly when the target is in a noncircular orbit. Such missions require a 6DOF precise position and attitude tracking maneuver that safely can avoid collision to the target and are capable of flying around. This thesis introduce a new guidance method for vectorial approach to the target in terminal rendezvous phase and applies a Sliding Mode method for attitude tracking control with respect to... 

Genome mutations whose effects are not specified pose one of the challenges in identifying genetic diseases. Utilizing wet lab tests to detect the pathogenicity of variants can be time-consuming and fiscally expensive. A rapid and cost-effective solution to this problem is the use of machine learning-based variant effect predictors, which have the ability to determine whether a mutation is pathogenic or not. The objective of this research is to predict the pathogenicity of genome variations. The proposed model exclusively utilizes the protein sequence as its input feature and does not have access to other protein features. The data used to construct the model comprises mutations with... 

The extensive use of nonlinear loads such as motor drives and new generation of home appliances has caused a deterioration of power quality in power systems. The use of active power filters due to the fast variation of the loads has been recommended by power engineering. In this method, the harmonic profiles are controlled by applying active filters in a distribution feeder. Optimal placement of active filters in a distribution system due to the increase of harmonic generation loads has attracted researchers. However placement of each filter is the major concern that researchers face. In this paper, a new objective function is introduced to determine the optimal number and location of active... 

Industrial wastewater treatment has always been one of the significant human being problems for the years. In particular, sewage containing heavy metals that, if discharged into nature, would have irreversible effects on the ecosystem and human health. Due to their toxic nature, heavy metals will reduce the efficiency of wastewater treatment systems if they are not efficiently treated. Also, the removal of Nitrate from the wastewater, which is one of the most stable nitrogen oxides, has always been a serious human problem in the treatment of effluents due to their high solubility in water. The simultaneous presence of nitrate and heavy metals in the effluent will cause many problems in the... 

One of the main concerns of industrial companies’ managers is providing an efficient logistics system. To achieve an efficient logistics system, the fleet planning problem is studied by many researchers in recent years. This problem consists of multiple sub-problems at three levels: operational, tactical, and strategic. These sub-problems are closely related to each other and need to be studied and addressed in an integrated manner. In this research, an attempt is made to provide an integrated framework to solve the vehicle routing problem (operational), outsourcing problem (tactical), and fleet composition problem (strategic). These problems have various uncertainties, including customer... 

Microgels, three-dimensional networks belonging to the family of smart materials, exhibit significant structural changes in response to external stimuli such as temperature. The rapid deformation of microgels upon thermal stimulation makes them a promising alternative for various mechanisms. Despite the similarities between hydrogels and microgels, many of their properties differ. Moreover, the Flory-Rehner model, typically used to describe the swelling behavior of temperature-sensitive hydrogels, only provides a qualitative description of microgel swelling. Nevertheless, previous numerical models of microgels have largely been based on the assumption that their behavior mirrors that of... 

Nowadays, vegetations have an important role in protecting ecological systems. One of the impacts of vegetation in water system is pollution diffusion. The physical characteristics of plants, affect how vegetation influence the diffusion phenomenon. Plants’ flexibility may change the drag force and pollution diffusion. Also density variations of vegetation in depths have important affects on flow characteristics.
In this study we investigate experimentally the affects of flexible vegetations and their density changes in depths on vertical mass transport. Thus the current flume has modeled for crossing flow through the plants. To model the steep plants, inclined rigid cylinders have been... 

The lack of road safety imposes heavy costs on society. The cost of treatment, disability, travel time and mental disorders are examples of costs caused by unsafe roads in a country. One of the most effective manners to improve road safety over the last decade is to use safe driving incentives and in particular usage-based insurance. Usage-based insurance reduces road accidents by internalizing the cost of driving violations and the cost of vehicle usage.Risky behaviors and driving violations, especially speed limits violations, have a significant effect on increasing unsafe road traffics. Accordingly, in this Ph.D. dissertation, a new scheme of usage-based insurance was introduced to reduce... 

Today, the need for high-speed machine tools, in areas such as defense, medical and electronic for producing parts with millimeter dimensions, and with features smaller than the millimeter, increased. To meet this need, the machine tool can be used with smaller dimensions and with high speed. These machines are able to produce these parts with high production rates.The project aims to improve technical design and construction of a micro spindle to achieve sustained speed about one hundred thousand RPM. In this project, the first step in understanding the fundamentals of the theory and the system components, and the whole operation was performed. The design is based on studies carried out in... 

In restructured power system, the Independent System Operator (ISO) implements Security Constraint Unit Commitment (SCUC) for clearing of day-ahead market. In this project, SCUC is also uses for simultaneous clearing of energy and reserve market. Spinning reserve and of generating units and Interruptible Loads (IL) are considered as system operating reserves in the proposed model. Some of IL usage restrictions such as maximum load curtailed, maximum curtailment hour in a day, maximum length of each curtailment and etc is also considered. One of these constraints is interruption time (the time between ISO’s request and IL’s Answer) which is very difficult to formulate. Expected Energy Not... 

Liquid crystals are the type of the matter which show different levels of symmetry and structural properties in between those of a crystalline solid and an isotropic liquid. They can form various phases such as uni- or bi-axial nematics that because of their applications in display technology, have been widely investigated. In this thesis, uniaxial and biaxial ellipsoid liquid crystals have been simulated by using molecular dynamics simulations using LAMMPS simulation software. By control of the density of the system in NVT ensemble, the phase transitions of the systems were investigated. In all the simulations, the mesogens interact with RE-squared coarse grained force field. By calculating...