Abstract Mobile Ad hoc networks are defined as the category of wireless networks that utilize multi-hop radio relaying and are capable of operating without the support of any fixed infrastructure Mobile Ad hoc Network (MANET) is more vulnerable to various attacks since it has no centralized or any pre-existing network structure. At the time of framing of a new security mechanism for MANET various... Mobile Ad hoc networks are defined as the category of wireless networks that utilize multi-hop radio relaying and are capable of operating without the support of any fixed infrastructure Mobile Ad hoc Network (MANET) is more vulnerable to various attacks since it has no centralized or any pre-existing network structure. At the time of framing of a new security mechanism for MANET various attack variations as well as their characteristics must be known. Jelly Fish periodic drop attack is a new Denial of Service (DoS) attack and passive attack which is difficult to detect as it follows the protocol rules and it works against closed loop flows such as TCP. In jellyfish attack, JF nodes randomly discard some packets over a specified period during communication process over the network. In this paper, periodic drop attack is implemented using AODV and OLSR routing protocols over voice based traffic in MANET. In addition to this, simulation results also illustrate the seriousness of the attacks caused by JF nodes and their effects on data communication. Read More Read Less

Abstract It is a key technology to select the optimal spatial resolution of the remote sensing imagery to achieve the accuracy of map scale in the process of drawing satellite remote sensing maps. In this paper, through investigating the relationship between pixel size, the minimum unit on the map, the image accuracy and the spatial resolution of images, the mathematical model of the optimal... It is a key technology to select the optimal spatial resolution of the remote sensing imagery to achieve the accuracy of map scale in the process of drawing satellite remote sensing maps. In this paper, through investigating the relationship between pixel size, the minimum unit on the map, the image accuracy and the spatial resolution of images, the mathematical model of the optimal collocation relationship between the high space resolution and map scale has been put forward. And the feasibility of the model has been verified by a range of experiments. Read More Read Less

Abstract The essay evaluates the modeling, control and analysis of a doubly-fed induction machine (DFIM) using a three level three stage voltage source inverter known as voltage source converter (VSC). VSC is utilized to control the extent and period of the rotor voltage in a proficient way and can consequently be used to control the dynamic and receptive force of the doubly fed induction... The essay evaluates the modeling, control and analysis of a doubly-fed induction machine (DFIM) using a three level three stage voltage source inverter known as voltage source converter (VSC). VSC is utilized to control the extent and period of the rotor voltage in a proficient way and can consequently be used to control the dynamic and receptive force of the doubly fed induction machine. The stator circuit of the DFIM may either be supplied by a variable recurrence VSC or straightforwardly from the a.c. system. Both cases are exhibited and analyzed. Distinctive torque and rate control strategies could be examined with the goal of wiping out the back electromotive power (EMF), which adversely affects the rotor current often considered as a load disturbance. Similarly, the essay will expound on the system of space vector control of doubly fed induction machine driving a permanent magnet synchronous generator that supplies a three stage a.c. load. The control methodology composed here is attempting to accomplish the utmost reduction of harmonic distortion in the voltage and current generated. The findings were analyzed in Simplorer 7 to demonstrate the adequacy of the proposed strategies for velocity and voltage control of doubly fed induction machine utilizing VSC. Read More Read Less