فهرست مطالب

  • Volume:8 Issue: 29, 2019
  • تاریخ انتشار: 1398/03/11
  • تعداد عناوین: 6
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  • Fatemeh Fakhar * Pages 1-19
    One of the methods for analyzing systems is simulation. Network simulation is a technique that models the behavior of the network by performing transaction calculations between different network entities and using mathematical formulas and taking observations from network products. A network simulator is a piece of software or hardware that predicts the behavior of a computer network without a real network. Users can customize the simulator to fulfill their analytical needs of their own systems. In the realm of research, the creation of a network, especially large networks, is difficult in a real-time scenario, and its implementation in the real world is not easily feasible and very costly. So simulators help network developers to control whether the network is capable of working in real time or not, or whether it has enough performance. This reduces the time and cost required to test the functionality of the network. In this paper, we have investigated and compared the simulation software of the network. For this purpose, 23 major network simulators are considered and the results of these comparisons are expressed in several different views in multi tables.
    Keywords: Simulation, network, network simulation software, general purpose simulator, comparison
  • Hadi Amos *, Majid Ghandchi Pages 21-24
    In this paper, the structure of SAW has been studied. In previous work in SAW, materials such as lithium niobium, lithium tantalite and gallium nitride were used in the structure of SAW, and thus had a low operating frequency and the highest reported operating frequency was about 4 GHz. In this paper, aluminum nitride and gallium nitride in the SAW structure are used in combination. The electrodes used in the structure are also made of aluminum. Comsol software was used to simulate the structure, and for the structure, the operating frequency was 7.02 GHz.and this wave guide by this design have a better performance of another structures
    Keywords: Nitride Aluminum, Surface Waves, Finite Element Method, Microelectromechanical Systems, Gallium Nitride
  • Yasser Mousalou* Pages 25-39

    Today, robots and unmanned aerial vehicles are being used extensively in modern societies. Due to a wide range of applications, it has attracted much attention among scientists over the past decades. This paper deals with the problem of the stability of a four-rotor flying robot called quadrotor, which is an under-actuated system, in the presence of operator or sensor failures. The dynamical model of quadrotor is expressed in terms of different physical phenomena by the Newton-Euler method. Subsequently, a back stepping control approach has been developed, considering actuator and sensor failures. The stability analysis based on the Lyapanov method shows that the designed control strategy maintains the stability of quadrotor closed loop dynamics even in the presence of failures. The simulations of the control system indicate that the proposed control strategy is capable of maintaining performance and maintains system stability in the event of a failure of the operator or sensor.

    Keywords: Robot, Quadrotor, under-actuated, back-stepping Controller, actuator, sensor failure
  • Foruzan Mehria, Ahmad Foruzantabarb Pages 41-52
    This paper is has addressed the Single Flexible Link Robot. The dynamical model is derived using Euler-Lagrange equation and then a proper controller is designed to suppress a  vibration based-on Input-Shaping (IS) method. But, IS control method is an open loop strategy. Due to the weakness of open loop control systems, a closed loop IS control system is proposed. The achieved closed loop control system becomes an input delay system. To control this delay system, a robust linear state feedback with proper gain matrix is designed based-on an LMI method. Finally, the simulation results are illustrated to verify closed loop control system behavior.
    Keywords: Flexible Link Robot, Input-Shaping control method, Linear Matrix Inequality (LMI), Delay system
  • Saeed Barghandan *, Masoud Solouki Pages 53-58
    Operator failures in controlled systems can reduce their operation, cause instability and even cause dangerous casualties and accidents. Flaw causes structural changes and parametric uncertainties in the control system, which requires a new modeling for the control system as well as new control methods. The design of the control is applied to the dynamic model in the presence of a defect in the radar, ellerron and motor operators. The intended damage for these operators is considered to be "locked in place", that is, after the defect, the control levels remain uncertain and constant. In this paper, we examine several different control methods for controlling the operation of operators in the presence of uncertainty.
    Keywords: Actuator fault, Adaptive control, PID Controller, back stepping control
  • S.Hossein Hosseini Nejad, Elham Nesabgharamaleki Pages 54-59

    Today persons sitting at either end of the world can speak with each other with the aid of wireless technology. Mobile ad hoc Network (MANET) is a type of wireless ad hoc network which is a collection of mobile devices that creates a random topology for communication. The advantage of MANET is that it does not require any central controller or base station. MANET is only a network in which devices work as a host as well as a router. Routing in ad hoc networks has become a popular research topic. There are several routing protocols developed for ad hoc networks. In MANET, it is a very difficult task to predict the performance of routing protocol under varying network conditions and scenarios. This review paper is discussing the three approaches of routing protocols such as Reactive (On demand), Proactive (table driven) and Hybrid routing protocols with their advantages and disadvantages.

    Keywords: MANET, Ad Hoc, Reactive, Proactive, Hybrid