Sharif Digital Repository

This study investigates the motion planning problem for multiple agents with nonlinear dynamics in environments with static obstacles. Designing safe, smooth, and optimal trajectories for a group of agents operating concurrently in a shared space is a critical challenge in robotics, multi-agent systems, and autonomous navigation. Traditional methods often rely on initial guesses close to the optimal solution or become computationally inefficient at large scales. To address these challenges, this thesis proposes a novel computational framework based on the Alternating Direction Method of Multipliers (ADMM) and the Convex Feasible Set (CFS) algorithm. The framework decomposes the overall... 

Due to safety critical applications of the embedded systems, reliability is one of the most important properties of these systems. Wireless networks also have error prone data transmission channels and limited power consumption. Therefore reliability and power conservation are two vital characteristics of the wireless network especially in embedded applications. Since achieving to a desirable level of data reliability is power consuming, we must consider a trade-off between power consumption and data reliability. In wireless networks power consumption can be categorized into: power consumption in wireless devices and power consumption in data transmission. For decrement of wireless devices... 

In this research, delamination in compound laminated materials under the I mode loading is studied. In this way, a Double Cantilever Beam is investigated, which is the only experiment to study delamination in standard compound laminated materials. At first, a survey and comprehension of the failure of these materials is performed and the major mode of failure, which is named Delamination Mode is understood. Next, a survey on the possible methods of investigating the delamination phenomena is presented. In the next chapter, possible numerical methods are analysed, and the better performance of Cohesive Zone Model and Virtual Crack Closure Technique is studied. In this research, using the... 

In recent years, deep learning models have become one of the most widely used models in the field of artificial intelligence by showing high accuracy in various applications, in some of which the accuracy and correctness of the output of the models are very important, and in case of an error, there will be a possibility of chaotic events. Along with the progress of deep learning models, attacks have also been introduced in this field that severely compromises the security of such models and affects the accuracy and correctness of their output. Data poisoning is an attack on deep learning models wherein the attacker manipulates some data examples and adds these poisoned data to the victim's... 

In recent years, there has been a trend toward outsourcing data to the cloud provider. These companies must tackle the data security challenges. Generally these parties are assumed to be honest but curious. In past years, the research communities have been investigating different solution to ensure confidentiality.
In addition to data confidentiality access and pattern confidentiality is a high-priority issue in some cases so. potential adversary should be unable to drive information from the observed access pattern to the outsourced data. Despite the fact that there are more investigation in the field of data confidentiality, concern over data security are the rise in outsourcing data,... 

The Cu-Cr10% ingots were prepared in induction furnace and these ingots were used to prepare CuCr25% in VAR. The percentages of elements were checked by chemical analysis. The ingots were divided to slices with 20gr mass and these slices were put in quartz tubes. The quartz tubes were assembled in melt spinning machine and the ribbons were quenched onto a rotating copper wheel. Three different wheel speeds, 8, 16, 36 m/s were chosen. The microstructure of the ribbons was examined using a scanning electron microscopy (SEM). The relationship between wheel speed and thickness of the ribbons were compared with mathematical modeling. The disk of ribbons with thickness of 0.5mm and radius of 5mm... 

Hydroxyurea is an anticancer drug that is commonly used to treat chronic myeloid leukemia (white blood cell cancer in bone marrow), polycythemia vera (red blood cell cancer), sickle cell anemia, solid tumors, and in particular leukemia. In this research, in addition to analyzing all available methods for synthesis of hydroxyurea, the most economical method for synthesis of hydroxyurea which is Hantzsch method was chosen; then we synthesized hydroxyurea crystals using a precipitation or crystallization process. To do so, two hydroxylamine hydrochloride and potassium cyanate reactants have been used in the semi batch reactor. Since the reaction efficiency and purity of the synthesized...