We consider the problem of locating a black hole in a synchronous, anonymous, and unoriented torus network using mobile agents. A black hole is a harmful network node that destroys any agent visiting it without leaving any trace. The objective is to locate the black hole using as few agents as possible. We present here an almost optimal deterministic algorithm for synchronous (partially) unorie...

by extending wireless networks and because of their different nature, some attacks appear in these networks which did not exist in wired networks. security is a serious challenge for actual implementation in wireless networks. due to lack of the fixed infrastructure and also because of security holes in routing protocols in mobile ad hoc networks, these networks are not protected against attack...

Recently, we derived an improved universal upper bound to the entropy of a charged system S ≤ π(2Eb − q2)/h̄. There was, however, some uncertainty in the value of the numerical factor which multiply the q2 term. In this paper we remove this uncertainty; we rederive this upper bound from an application of the generalized second law of thermodynamics to a gedanken experiment in which an entropy-be...

A comprehensive treatment of black hole thermodynamics in two-dimensional dilaton gravity is presented. We derive an improved action for these theories and construct the Euclidean path integral. An essentially unique boundary counterterm renders the improved action finite on-shell, and its variational properties guarantee that the path integral has a well-defined semi-classical limit. We give a...

Mobile ad hoc networks (MANETs) are extensively used in military and civilian applications. The dynamic topology of MANETs allows nodes to join and leave the network at any point of time. This generic characteristic of MANET has rendered it vulnerable to security attacks. In our research, we will address the problem of black hole attack. In this attack, a malicious node falsely advertise shorte...

A black hole is a highly harmful stationary process residing in a node of a network and destroying all mobile agents visiting the node, without leaving any trace. We consider the task of locating a black hole in a (partially) synchronous tree network, assuming an upper bound on the time of any edge traversal by an agent. The minimum number of agents capable of identifying a black hole is two. F...

In Mobile Adhoc Networks (MANETs), routing attacks are considered as a serious issue. However, in the presence of malicious nodes, the networks are affected by various kinds of attacks. The malicious node(s) can attack a MANET in different ways, such as sending fake messages several times; fake routing information and advertising fake links to disrupt routing operations. Black hole attacks are ...

A black hole is a highly harmful stationary process residing in a node of a network and destroying all mobile agents visiting the node, without leaving any trace. We consider the task of locating a black hole in a (partially) synchronous tree network, assuming an upper bound on the time of any edge traversal by an agent. The minimum number of agents capable to identify a black hole is two. For ...