Karim Tamine

Methods and data structures for virtual world exploration

This paper is dedicated to virtual world exploration techniques that help humans to understand a 3D scene. The paper presents a technique to calculate the quality of a viewpoint for a scene, and describes how this information can be used. A two-step method for an automatic real-time scene exploration is introduced. In the first step, a minimal set of “good” points of view is determined; in the second step, these viewpoints are used to compute a camera path around the scene. The proposed method enables one to get a good comprehension of a single virtual artifact or of the scene structure.

A hybrid multiagent routing approach for wireless ad hoc networks

Wireless ad-hoc networks are infrastructureless networks that comprise wireless mobile nodes able to communicate each other outside wireless transmission range. Due to frequent network topology changes in one hand and the limited underlying bandwidth in the other hand, routing becomes a challenging task. In this paper we present a novel routing algorithm devoted for mobile ad hoc networks. It entails both reactive and proactive components. More precisely, the algorithm is based on ant general behavior, but differs from the classic ant methods inspired from Ant-Colony-Optimization algorithm [1]. We do not use, during the reactive phase, a broadcasting technique that exponentially increases the routing overhead, but we introduce a new reactive route discovery technique that considerably reduces the communication overhead. In the simulation results, we show that our protocol can outperform both Ad hoc On-demand Distance Vector (AODV) protocol [2], one of the most important current state-of-the-art algorithms, and AntHocNet protocol [5], one of the most important ant-based routing algorithms, in terms of end-to-end delay, packet delivery ratio and the communication overhead.

A Distributed Intrusion Detection Model Based on a Society of Intelligent Mobile Agents for Ad Hoc Network

The evolution of wireless network technologies and the recent advances in mobile computing hardware have made possible the introduction of various applications in mobile adhoc networks. Not only is the infrastructure of these networks inherently vulnerable but they have increased requirements regarding their security as well. As intrusion prevention mechanisms, such as encryption and authentication, are not sufficient regarding security, we need a second line of defence, Intrusion Detection. The focus of this paper is on distributed and intelligent intrusion detection. We propose a model for building a distributed and behavioural intrusion detection system by using a classification method.

AntTrust: A Novel Ant Routing Protocol for Wireless Ad-hoc Network Based on Trust between Nodes

A wireless ad-hoc network is a network which does not use any infrastructure such as access points or base station. Instead, the mobile nodes forward packets to each others, allowing communication among nodes outside wireless transmission range. In this dynamic network, each node is considered as a mobile router but in an energy-conserving manner. This fact makes node an active element in the network which is able of the best and of the worst. Actually, a malicious node can easily disrupt the proper functioning of the routing by simply refusing to forward routing message (misbehavior node), inject the wrong routing packets, modifying others, etc. In this paper, we propose a new routing protocol for wireless ad-hoc network based on multi-agent systems and particularly on ant behavior. The novelty of our protocol relies in the fact that, apparently for the first time, a protocol combines at the same time routing on one side and trust level and reputation between nodes on the other side. This combination permits to increase the security of route establishment. More generally, this protocol opens the door to the use of different agents for obtaining different mixed functionalities, routing and trust level in this paper but also other functionalities like key-distribution.

A protocol for file sharing, anonymous and confidential, adapted to P2P networks

Peer-To-Peer networks have become increasingly common as a means of transferring files over Internet. However, user anonymity and privacy are not typically protected in such peer-to-peer systems. An adversary can gain knowledge about not only the content of the files being transferred but also the senders and receivers of the files. In this paper, we describe the design and experimentation of AnonymP2P a new Anonymous and confidential P2P system. AnonymP2P works on the principle of social networks with nodes identified by virtual addresses where each node can change randomly its neighbors to avoid an attacker to surround it. AnonymP2P uses also a process of data request and file sharing that differs from that found in other P2P networks; indeed the “path” of the file transfer is not necessary the reverse “path” of the data request but a set of “paths” built by a set of control message. The “path” of the data request and the “paths” of the file transfer are used by sender and receiver to exchange a secret by the Diffie-Helman protocol and thus reduce the probability of success of Man-In-The-Middle attack. We show that our protocol presents a good trade-off between efficiency on the side and anonymous and confidential communications on the other side.