EURASIP Journal on Advances in Signal Processing Special issue on Signal Processing Applications in Network Intrusion Detection Systems In recent years, network intrusion detection has attracted a lot of attention in the area of network security. Network intrusions cause threat and damage mainly in two ways. First, the intruders probe, gather, and deduce sensitive information about target hosts in an effort to gain unauthorized access to the target hosts and their networks. Second, the intruders inject huge waves of unwanted packets into the target networks, aiming to disrupt the normal communications carried on by the target networks. It is therefore very important to implement appropriate network intrusion detection systems (NIDSs) to monitor the network and detect the intrusion before it is too late. Signal processing techniques have found applications in NIDSs because of their ability to detect novel intrusions and attacks, which cannot be achieved by signature-based NIDS. It has been shown that network traffic possesses the property of self-similarity. Therefore, the objective of NIDS based on signal processing techniques is to profile the pattern of normal network traffic or application-level behavior and model intrusions or unwanted traffic as anomalies. Wavelets, entropy analysis, and data mining techniques are examples in this regard. However, the major challenges of the signal processing-based approaches lie in the adaptive modeling of normal network traffic and the high false alarm rate due to the inaccuracy of the modeled normal traffic pattern. The emergence of a variety of wireless networks and the mobility of nodes in such networks only add to the complexity of the problems. The goal of this special issue is to introduce state-of-the-art techniques and encourage research regarding various aspects in the application of signal processing techniques to network intrusion detection systems. In particular, the special issue encourages novel solutions that improve the accuracy and adaptivity of intrusion detection and addresses the automation of intrusion classification and correlation. Topics of interest include (but are not limited to): * Data-mining-based IDS * Multirate filtering and wavelets * Monte Carlo methods integration * Anomalous network traffic modeling * Anomalous application-level behavior modeling * Performance analysis and evaluation * Real-time analysis techniques * Intrusion correlation * Automated detection and classification of intrusions and anomalies * Clustering-based IDS * Sampling techniques in intrusion detection * Data streaming algorithms for traffic analysis * Adaptive detection techniques * Data fusion in distributed intrusion detection Authors should follow the EURASIP Journal on Advances in Signal Processing manuscript format described at the journal site http://www.hindawi.com/journals/asp/. Prospective authors should submit an electronic copy of their complete manuscript through the EURASIP Journal on Advances in Signal Processing Manuscript Tracking System at http://mts.hindawi.com/ according to the following timetable: Manuscript Due September 1, 2007 First Round of Reviews December 1, 2007 Publication Date March 1, 2008 Guest Editors: Chin-Tser Huang, Department of Computer Science and Engineering, University of South Carolina, Columbia, SC 29208, USA Rocky K. C. Chang, Department of Computing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong Polly Huang, Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan