Sharif Digital Repository

Pyroshock Test is one of important environment tests in satellite design process.pyroshock or pyrotechnic shock is one of loads that exerted on spacecraft and it's subsystems during launch process. pyroshock can cause failure in some subsystems like sensitive electronic parts, solar cells and so on. For this reason it's necessary to make sure about strength of component under pyroshock which can be done by pyroshock simulator.The purpose of this research is to design a pyroshock simulator that can simulate a pyroshock with given SRS (Shock Response Spectrum) for satellite components.Requirements and constraints for design have been defined such as test item dimensions,weight range and also... 

Pyrotechnic devices are widely used by the aerospace and defense industries and consist of a broad family ofsophisticated devices using self-contained energy sourcessuch as explosives and/or pyrotechnic compositions.Pyrotechnic shock, or pyroshock, is the transient oscillatoryresponse of a structure to loading (high frequency, highmagnitude stress waves) induced by the detonation ofpyrotechnic devices incorporated into or attached to thestructure.Pyroshock Test is one of importantenvironmental tests in satellite design process. Pyroshock is one of loads that exerted on spacecraft and it's subsystems during launch process. Pyroshock can cause failure in some subsystems like sensitive... 

According to recent advancements in digital circuit technology and new constraints for digital systems, scholars have researched to find a replacement for traditional copper links that is used to connect the embedded processing elements in a chip. Optic NoCs and wireless NoCs are two promising solutions to overcome challenges in traditional NoCs.
In this thesis, an innovative 3D NoC architecture is proposed which consists of four 2D mesh-based networks and they are connected via four wireless sub-networks as backbones. It is estimated that, the proposed architecture shrinks the power consumption at least 35 percent relatively due to the gate-level simulations. Thus, a better scaling and... 

We call medium and large networksSDN, which they can managed by centralized software. In this networks instead ofmaking routing decisions byhardware, software is making decisions by using pre-defined conditions and with each packet behave differently. With the increasing development of real-time services such as voice services the importance of network monitoring system is increasing day after day. IN order to ensure quality of service, network service providers must measure network status with metrics such as delay and packet loss rate. Obtaining accurate and meaningful statistics from network status, provide abilities to service providers to measuretheir network health and estimate amount... 

Miscible displacement in fluid flowing through a porous medium plays an important role in many environmental and industrial applications; for instance, miscible displacements in enhanced oil recovery processes and pollutant spreading in groundwater. A large number of numerical approaches have been developed to solve the advection-dispersion equation that describes the behavior of miscible displacement in porous media. Most of these numerical models suffer from numerical dispersion. Random walk seems to be an effective method to overcome this problem especially in heterogeneous media. Here, a random walk model was developed and used for simulating miscible displacement in heterogeneous porous... 

In this project a knee prostheses wear testing simulator based on a parallel mechanism for applying forces and torques, is designed. First according to ISO 14243 standard required degrees of freedom and design constraints are determined and also regarding simulator requirements some considerations in design are outlined. Considering all of these parameters, literature has been searched for proper parallel mechanism and because no suitable parallel mechanism, which is a 3 DoF 2T1R paralle mechanism with rotational degree about z axis, has been found; several new designs of proper mechanism have been presented. Scoring different mechanisms according to outcomed parameters from standard and... 

Total knee replacement surgery is the most common joint replacement in the world. Considering the increasing rate of this procedure and costs and difficulties of the repeated operation, many efforts have been made to improve the performance and lifetime of implants. The Polyethylene component of the implant is the most prone component to fail due to wear. To evaluate new knee prosthesis designs, it is necessary to have a wear test simulator. Objective of this project is to detail design a knee prosthesis wear simulator according to ISO 14243 in order to investigate the performance of prosthesises in long term and under in-vivo conditions. During this project, studies have been made to get... 

In this research, the mechanical section of a reduced-scale hybrid vehicle simulator was designed and fabricated. In order to scale down the vehicle dynamics, a method based on dimensional analysis was proposed. An internal combustion engine and an electric motor were selected as power sources and then, scaling was performed, according to the specifications of the combustion engine. Afterwards, the power transmission system was designed first in concept and then in more detail. Finally, the design was manufactured and assembled. The study was made in conjunction with another study responsible for the controlling section of the work, conducted by Safabakhsh The sponsor of these two researches... 

Energy harvesting systems have been recently considered as an alternative to battery- operated systems, especially when the usage of battery-based systems is limited or the process of charging the batteries becomes infeasible. As one of the most important marketing factors for IoT devices, these systems are expected to reach around 100 billion objects in the near future.On the other hand, the emergence of nonvolatile memories due to useful features such as high density and low leakage energy has received much attention that allows the system designer to store the CPU state while the system’s input power is lost. Moreover, system parameters such as capacitance size, frequency, and power... 

With the increasing advancement of technology and available information, finding suitable content for users is one of the significant challenges. Recommender systems have emerged as an effective solution to confront these challenges. Reinforcement learning can be employed as an effective approach to designing and implementing recommender systems. However, there are various challenges and complexities in the context of reinforcement learning applied to recommendation systems. In this context, Online users are treated as the environment, and concepts like reward functions and environment dynamics are not clearly defined, complicating the reinforcement learning process. In this thesis, a...