Distributed denial of service (DDoS) attacks continues to grow as a threat to organizations worldwide. From the first known attack in 1999 to the highly publicized Operation Ababil, the DDoS attacks have a history of ...Distributed denial of service (DDoS) attacks continues to grow as a threat to organizations worldwide. From the first known attack in 1999 to the highly publicized Operation Ababil, the DDoS attacks have a history of flooding the victim network with an enormous number of packets, hence exhausting the resources and preventing the legitimate users to access them. After having standard DDoS defense mechanism, still attackers are able to launch an attack. These inadequate defense mechanisms need to be improved and integrated with other solutions. The purpose of this paper is to study the characteristics of DDoS attacks, various models involved in attacks and to provide a timeline of defense mechanism with their improvements to combat DDoS attacks. In addition to this, a novel scheme is proposed to detect DDoS attack efficiently by using MapReduce programming model.展开更多
This paper considers the geometric design of crab-like walkers and climbers, without decoupling leg design from overall machine design. Crab-like machines represent an important sub-class of multi-legged robots, bein...This paper considers the geometric design of crab-like walkers and climbers, without decoupling leg design from overall machine design. Crab-like machines represent an important sub-class of multi-legged robots, being particularly well suited to crossing difficult terrains. Firstly, the kinematic configurations and constraints are described, which determine the machine’s kinematic characteristics. The influence of the design parameters on the kinematic workspace is discussed. Finally, a two stage design methodology is presented, comprising kinematic design and design optimisation, the latter being based on the use of design maps rather than numerical optimisation. The performance measures considered during design optimisation include kinematic, static and quasi-static measures.展开更多
Distributed Denial of Service (DDoS) attacks in the networks needs to be prevented or handled if it occurs, as early as possible and before reaching the victim. Dealing with DDoS attacks is difficult due to their prop...Distributed Denial of Service (DDoS) attacks in the networks needs to be prevented or handled if it occurs, as early as possible and before reaching the victim. Dealing with DDoS attacks is difficult due to their properties such as dynamic attack rates, various kinds of targets, big scale of botnet, etc. Distributed Denial of Service (DDoS) attack is hard to deal with because it is difficult to distinguish legitimate traffic from malicious traffic, especially when the traffic is coming at a different rate from distributed sources. DDoS attack becomes more difficult to handle if it occurs in wireless network because of the properties of ad hoc network such as dynamic topologies, low battery life, multicast routing, frequency of updates or network overhead, scalability, mobile agent based routing, and power aware routing, etc. Therefore, it is better to prevent the distributed denial of service attack rather than allowing it to occur and then taking the necessary steps to handle it. This paper discusses various the attack mechanisms and problems due to DDoS attack, also how MANET can be affected by these attacks. In addition to this, a novel solution is proposed to handle DDoS attacks in mobile ad hoc networks (MANETs).展开更多
This paper deals with two novel structures for mobile robots. The original inspiration of the robots comes from a sala- mander and a specific kind of spiders. Our robots have some especial moving capabilities causing ...This paper deals with two novel structures for mobile robots. The original inspiration of the robots comes from a sala- mander and a specific kind of spiders. Our robots have some especial moving capabilities causing to increase the robot ma- neuverability. Indeed, the capability of rolling motion is added to ordinary quadruped robots. This capability causes increment in maneuvering of the robots. Manipulators can be embedded into the robots to add the ability of transferring materials into the shell and conducting some tasks such as repairing. In this paper, after analysis of motion principles of the rolling robots, their dynanlic equations are derived. Different simulations of two bioinspired mobile robots are presented in order to scrutinize various capabilities of the proposed designs. Walking capabilities of the robots and their advantages are discussed in detail. The comprehensive simulation results of the robots in various motion modes are presented. Finally the first prototype is introduced to verify the motion mechanisms.展开更多
文摘Distributed denial of service (DDoS) attacks continues to grow as a threat to organizations worldwide. From the first known attack in 1999 to the highly publicized Operation Ababil, the DDoS attacks have a history of flooding the victim network with an enormous number of packets, hence exhausting the resources and preventing the legitimate users to access them. After having standard DDoS defense mechanism, still attackers are able to launch an attack. These inadequate defense mechanisms need to be improved and integrated with other solutions. The purpose of this paper is to study the characteristics of DDoS attacks, various models involved in attacks and to provide a timeline of defense mechanism with their improvements to combat DDoS attacks. In addition to this, a novel scheme is proposed to detect DDoS attack efficiently by using MapReduce programming model.
文摘This paper considers the geometric design of crab-like walkers and climbers, without decoupling leg design from overall machine design. Crab-like machines represent an important sub-class of multi-legged robots, being particularly well suited to crossing difficult terrains. Firstly, the kinematic configurations and constraints are described, which determine the machine’s kinematic characteristics. The influence of the design parameters on the kinematic workspace is discussed. Finally, a two stage design methodology is presented, comprising kinematic design and design optimisation, the latter being based on the use of design maps rather than numerical optimisation. The performance measures considered during design optimisation include kinematic, static and quasi-static measures.
文摘Distributed Denial of Service (DDoS) attacks in the networks needs to be prevented or handled if it occurs, as early as possible and before reaching the victim. Dealing with DDoS attacks is difficult due to their properties such as dynamic attack rates, various kinds of targets, big scale of botnet, etc. Distributed Denial of Service (DDoS) attack is hard to deal with because it is difficult to distinguish legitimate traffic from malicious traffic, especially when the traffic is coming at a different rate from distributed sources. DDoS attack becomes more difficult to handle if it occurs in wireless network because of the properties of ad hoc network such as dynamic topologies, low battery life, multicast routing, frequency of updates or network overhead, scalability, mobile agent based routing, and power aware routing, etc. Therefore, it is better to prevent the distributed denial of service attack rather than allowing it to occur and then taking the necessary steps to handle it. This paper discusses various the attack mechanisms and problems due to DDoS attack, also how MANET can be affected by these attacks. In addition to this, a novel solution is proposed to handle DDoS attacks in mobile ad hoc networks (MANETs).
文摘This paper deals with two novel structures for mobile robots. The original inspiration of the robots comes from a sala- mander and a specific kind of spiders. Our robots have some especial moving capabilities causing to increase the robot ma- neuverability. Indeed, the capability of rolling motion is added to ordinary quadruped robots. This capability causes increment in maneuvering of the robots. Manipulators can be embedded into the robots to add the ability of transferring materials into the shell and conducting some tasks such as repairing. In this paper, after analysis of motion principles of the rolling robots, their dynanlic equations are derived. Different simulations of two bioinspired mobile robots are presented in order to scrutinize various capabilities of the proposed designs. Walking capabilities of the robots and their advantages are discussed in detail. The comprehensive simulation results of the robots in various motion modes are presented. Finally the first prototype is introduced to verify the motion mechanisms.