Web Anomaly Host-Based IDS, Using Computational Intelligence Approach

, M.Sc. Thesis Sharif University of Technology Javadzadeh, Ghazaleh (Author) ; Azmi, Reza (Supervisor)

Abstract

In this thesis we propose a two-layer hybrid fuzzy genetic algorithm for designing anomaly based an Intrusion Detection System. Our proposed algorithm is based on two basic Genetic Based Machine Learning Styles (i.e. Pittsburgh and Michigan). The Algorithm supports multiple attack classifications; it means that the algorithm is able to detect five classes of network patterns consisting of Denial of Service, Remote to Local, User to Root, Probing and Normal class.
Our proposed algorithm has two approaches. In the first approach we choose Pittsburgh style as the base of the algorithm that provides a global search. Then combine it with Michigan style to support local search. In this...

Intelligent Anomaly-Based Intrusion Detection in Linux Kernel

, M.Sc. Thesis Sharif University of Technology Almasian, Negar (Author) ; Azmi, Reza (Supervisor)

Abstract

The growth of intelligent attacks has prompted the designers to envision the intrusion detection as a built-in process in operating systems. This thesis investigates a novel anomaly-based intrusion detection mechanism which utilizes the manner of interactions between users and kernel processes to bring functionality to this notion. In fact, this mechanism is inspired by homeostatic behavior of an organism. Homeostatic is the property of an open system or a closed system, particularly a living organism, which regulates its internal environment to maintain a stable, constant condition. Such a developed mechanism can provide the computer system with a high level of protection from artificial...

Web Anomaly Host Based IDS, a Machine Learning Approach

, M.Sc. Thesis Sharif University of Technology Khalkhali, Iman (Author) ; Azmi, Reza (Supervisor) ; Khansari, Mohammad (Co-Advisor)

Abstract

Web servers and web applications are susceptible to different attacks. In order to detect web-based attacks Intrusion detection systems (IDS) should be equipped with a large number of signatures. Unfortunately various types of web threats are increasingly growing and so detection and prevention of all these new and old attacks is exhaustive and really difficult.This thesis represents a designed system for intrusion detection that uses different techniques to discover vulnerabilities with derived patterns and also some user behavior based attacks against web applications. This was done by using new dataset which was generated by new log file.The primary objective of this thesis shows the...

Web User Profile Clustering Using Artificial Immune System

, M.Sc. Thesis Sharif University of Technology Azimpour Kivi, Mozhgan (Author) ; Azmi, Reza (Supervisor) ; Khansari, Mohammad (Supervisor)

Abstract

Nowadays, a need for intelligent system that can assist web users in acquiring their desired information has been highlighted. In particular a mechanism for web user profiling which involves knowing the users and providing them with their preferred information is recommended to any website. To address this issue, Web Usage Mining (WUM) techniques have attracted many attentions. WUM is a kind of web mining process that tries to extract interesting usage patterns from the data that are obtained from the interaction of users with the web. The most important drawback of conventional, data mining based, WUM system is their inability to continuously learn the evolving patterns of web usage. On the...

Computational Modeling and Mining of Trust and Reputation in Social Networks Based on Soft Computing Approach

, M.Sc. Thesis Sharif University of Technology Rabiee Kenari, Yasaman (Author) ; Azmi, Reza (Supervisor) ; Sedighi Moshkenani, Mohsen (Supervisor)

Abstract

Nowadays trust has become one of the main challenges of every online social network. The open and decentralized nature of Peer-to-Peer network makes it vulnerable to be exploited by malicious users to distribute tampered and harmful contents. We propose a dynamic computational trust model based on a neuro-fuzzy approach and implemented it on Gnutella network. The model is a novel application of control systems approach for evaluating trust and reputation in P2P networks. We utilize Local Linear Model Tree (LOLIMOT) to perform a nonlinear dynamic system identiffcation and thus to approximate trust. The performance of our reputation-based trust model is evaluated by simulation. We create a...

Robust decoding of DFT-based error-control codes for impulsive and additive white Gaussian noise channels

, Article IEE Proceedings: Communications ; Volume 152, Issue 3 , 2005 , Pages 265-271 ; 13502425 (ISSN) Azmi, P ; Marvasti, F ; Sharif University of Technology

2005

Abstract

A novel decoding technique for DFT-based error control codes that is robust against quantisation noise and additive white Gaussian noise is proposed. The algorithm simultaneously determines the number and the positions of the corrupted samples. In contrast to the conventional decoding technique, the proposed decoding method is stable in the presence of both quantisation noise and additive white Gaussian noise. © IEE, 2005

A pseudo-inverse based iterative decoding method for DFT codes in erasure channels

, Article IEICE Transactions on Communications ; Volume E87-B, Issue 10 , 2004 , Pages 3092-3095 ; 09168516 (ISSN) Azmi, P ; Marvasti, F ; Sharif University of Technology

Institute of Electronics, Information and Communication, Engineers, IEICE 2004

Abstract

One of the categories of decoding techniques for DFT codes in erasure channels is the class of iterative algorithms. Iterative algorithms can be considered as kind of alternating mapping methods using the given information in a repetitive way. In this paper, we propose a new iterative method for decoding DFT codes. It will be shown that the proposed method outperforms me well-known methods such as Wiley/Marvasti, and ADPW methods in the decoding of DFT codes in erasure channels

A novel demodulation technique for recovering PPM signals in the presence of additive noise

, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 3124 , 2004 , Pages 541-547 ; 03029743 (ISSN); 3540225714 (ISBN); 9783540225713 (ISBN) Azmi, P ; Marvasti, F ; Sharif University of Technology

Springer Verlag 2004

Abstract

In this paper, we propose a novel method for demodulating Pulse Position Modulation (PPM) signals based on Reed-Solomon decoding algorithm. It is shown that the proposed technique outperforms the conventional demodulating method base on Reed-Solomon algorithm in case that the PPM signals are corrupted by Additive White Gaussian Noise (AWGN). © Springer-Verlag 2004

A novel iterative decoding method for DFT codes in erasure channels

, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 3124 , 2004 , Pages 548-553 ; 03029743 (ISSN); 3540225714 (ISBN); 9783540225713 (ISBN) Azmi, P ; Marvasti, F ; Sharif University of Technology

Springer Verlag 2004

Abstract

One of the categories of decoding techniques for DFT codes in erasure channels is the class of iterative algorithms. Iterative algorithms can be considered as kind of alternating mapping methods using the given information in a repetitive way. In this paper, we propose a new iterative method for decoding DFT codes. It will be shown that the proposed method outperforms the well-known methods such as Wiley/Marvasti, and ADPW methods in the decoding of DFT codes in erasure channels. © Springer-Verlag 2004

Generalised Fourier transform-domain technique for narrowband interference suppression in CDMA communication systems

, Article Electronics Letters ; Volume 37, Issue 10 , 2001 , Pages 652-654 ; 00135194 (ISSN) Azmi, P ; Nasiri Kenari, M ; Sharif University of Technology

2001

Abstract

A generalisation of Fourier transform-domain technique for narrowband interference suppression in CDMA communication systems is introduced. In this technique, first the sum of a number of sinusoids each modulated by a polynomial is chosen as a model for the narrowband interference. Then, by fitting the received signal on the proposed model, an estimate of the narrowband interference signal is obtained, and its effect is subtracted from the received signal

Internally channel-coded framed time-hopping fiber-optic CDMA communications

, Article IEEE/OSA Journal of Lightwave Technology ; Vol.23, No.11, PP. 3702-3707, Nov. 2005 Azmi, P ; Nasiri-Kenari, M ; Salehi, J. A ; Sharif University Of Technology

Abstract

Due to the low cardinality of optical orthogonal codes (OOCs) with a correlation value of 1, the capability of an internal channel-coding scheme cannot be applied effectively for an increasing number of simultaneous users in a typical fiber-optic code division multiple-access (FO-CDMA) system. In this paper, we consider applying the internal channel-coding scheme to the framed time-hopping (FTH) FO-CDMA system. Due to the extremely high cardinality of the spreading sequence in FTH FO-CDMA, the technique highlights the ability of the internal channel-coding scheme to increase the effective number of users in an FO-CDMA system. For the FTH FO-CDMA system, we only consider a Poisson...

An efficient method for demodulating ppm signals based on reed-solomon decoding algorithm

, Article Signal Processing ; Volume 84, Issue 10 , 2004 , Pages 1823-1836 ; 01651684 (ISSN) Azmi, P ; Meleas, D ; Marvasti, F ; Sharif University of Technology

Elsevier 2004

Abstract

In this paper, we propose an efficient method for demodulating pulse position modulation (PPM) signals based on Reed-Solomon decoding algorithm. It is shown that the proposed technique outperforms other demodulating methods such as those based on Lagrange, Spline, and Iterative algorithms. Furthermore, the proposed method is generalized to the case that the PPM signal is corrupted by additive white Gaussian noise. © 2004 Elsevier B.V. All rights reserved

Off-line Arabic/Farsi handwritten word recognition using RBF neural network and genetic algorithm

, Article Proceedings - 2010 IEEE International Conference on Intelligent Computing and Intelligent Systems, ICIS 2010, 29 October 2010 through 31 October 2010, Xiamen ; Volume 3 , 2010 , Pages 352-357 ; 9781424465835 (ISBN) Bahmani, Z ; Alamdar, F ; Azmi, R ; Haratizadeh, S ; Sharif University of Technology

2010

Abstract

In this paper an off-line ArabiclFarsi handwritten recognition Algorithm on a subset of Farsi name is proposed. In this system, There is no sub-word segmentation phase. Script database includes 3300 images of 30 Farsi common names. The features are wavelet coefficients extracted from smoothed word image profiles in four standard directions. The Centers of competitive layer of RBF neural network have been determined by combining GA and K-Means clustering algorithm. Weights of supervised layer has been trained by using LMS rule and the distances of feature vector of each sample to the centre of RBF network have been computed based on warping function. Experimental results show advantages of...

A new segmentation technique for multi font Farsi/Arabic texts

, Article 2005 IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP '05, Philadelphia, PA, 18 March 2005 through 23 March 2005 ; Volume II , 2005 , Pages II757-II760 ; 15206149 (ISSN); 0780388747 (ISBN); 9780780388741 (ISBN) Omidyeganeh, M ; Nayeb, K ; Azmi, R ; Javadtalab, A ; Sharif University of Technology

2005

Abstract

Segmentation is a very important stage of Farsi/Arabie character recognition systems. A new segmentation algorithm -for multi font Farsi/Arabic texts- based on the conditional labeling of the up contour and down contour is presented. A pre-processing technique is used to adjust the local base line for each subword. This algorithm uses adaptive base line for each subword to improve the segmentation results. This segmentation algorithm, in addition to up and down contours, takes advantage of their curvatures also. The algorithm was tested on a data set of printed Farsi texts, containing 22236 characters, in 18 different fonts. 97% of characters were correctly segmented. © 2005 IEEE

Soft-input decoder for decoding of internally channel coded fiber-optic CDMA communication systems

, Article IEEE Transactions on Communications ; Volume 50, Issue 12 , 2002 , Pages 1994-2002 ; 00906778 (ISSN) Azmi, P ; Nasiri Kenari, M ; Salehi, J. A ; Sharif University of Technology

2002

Abstract

In this paper, we propose using a soft-input decoder for the decoding of internally convolutional coded Poisson noise-dominated fiber-optic code-division multiple-access (CDMA) communication systems using optical orthogonal codes. We first compute the coded symbol log-likelihoods at the output of the Poisson noise-dominated channel, which is then used by a soft-input maximum-likelihood decoder, for a fiber-optic CDMA system assuming both on-off keying and binary pulse position modulation schemes. Furthermore, we develop a discrete soft-output channel model for a Poisson noise-dominated channel, with which we evaluate the upper bound on the bit error probability of the internally coded...

Internally bandwidth efficient coded fiber-optic CDMA communication systems with multistage decoding

, Article 2002 IEEE International Symposium on Information Theory, Lausanne, 30 June 2002 through 5 July 2002 ; 2002 , Pages 475- ; 21578095 (ISSN) Azmi, P ; Nasiri Kenari, M ; Salehi, J. A ; Sharif University of Technology

2002

Abstract

The structure and performance of a multistage decoding scheme for an internally bandwidth efficient coded fiber-optic code division multiple access (CDMA) communication system were studied. The decoder was implemented in several stages where the interfering users' coded symbol decisions obtained in previous stage was applied to compute the likelihood of the coded symbols of the desired users. Results showed that by using hard-input decoder, the bandwidth efficient internal channel-coding scheme improved the performance of an uncoded scheme with the same bandwidth

Multistage decoding for internally bandwidth efficient coded poisson fiber-optic CDMA communication systems

, Article Journal of Lightwave Technology ; Volume 20, Issue 8 , 2002 , Pages 1342-1349 ; 07338724 (ISSN) Azmi, P ; Nasiri Kenari, M ; Salehi, J. A ; Sharif University of Technology

2002

Abstract

In this paper, we consider the structure and performance of a multistage decoding scheme for an internally bandwidth efficient convolutionally coded Poisson fiber-optic code division multiple access (CDMA) communication system. The decoder is implemented electronically in several stages in which in each stage, the interfering users' coded bit decisions obtained in the previous stage is applied for computing the likelihood of the coded symbols of the desired user. The first stage is a soft-input Viterbi decoder for the internally coded scheme, in which the soft-input coded symbol likelihood values are computed by considering the multiuser interference as a noise signal. The likelihood of...

Internally bandwidth efficient channel coding for fiber-optic CDMA communication systems with soft-input decoding

, Article 2002 International Conference on Communications (ICC 2002), New York, NY, 28 April 2002 through 2 May 2002 ; Volume 5 , 2002 , Pages 2922-2926 ; 05361486 (ISSN) Azmi, P ; Nasiri Kenari, M ; Salehi, J. A ; Sharif University of Technology

2002

Abstract

In this manuscript, we consider using soft-input decoder for internally bandwidth efficient convolutionally coded fiber-optic Code Division Multiple Access (CDMA) communication systems using Optical Orthogonal Codes (OOC). The convolution codes that are used for demonstrating the capabilities of the soft-input decoder are Super Orthogonal Codes (SOC). These codes are near optimal and have a relatively low complexity. We evaluate the upper bounds on the bit error probability of the internally coded fiber-optic CDMA system using the soft-input and hard-input decoders assuming both On-Off Keying (OOK) and Binary Pulse Position Modulation (BPPM) schemes. It is shown that the soft-input decoder...

Internally channel-coded framed time-hopping fiber-optic CDMA communications

, Article Journal of Lightwave Technology ; Volume 23, Issue 11 , 2005 , Pages 3702-3707 ; 07338724 (ISSN) Azmi, P ; Nasiri Kenari, M ; Salehi, J. A ; Sharif University of Technology

2005

Abstract

Due to the low cardinality of optical orthogonal codes (OOCs) with, a correlation value of 1, the capability of an internal channel-coding scheme cannot be applied effectively for an increasing number of simultaneous users in a typical fiber-optic code division multiple-access (FO-CDMA) system. In this paper, we consider applying the internal channel-coding scheme to the framed time-hopping (FTH) FO-CDMA system. Due to the extremely high cardinality of the spreading sequence in FTH FO-CDMA, the technique highlights the ability of the internal channel-coding scheme to increase the effective number of users in an FO-CDMA system. For the FTH FO-CDMA system, we only consider a Poisson...

New vector quantization-based techniques for reducing the effect of channel noise in image transmission

, Article Signal Processing ; Volume 84, Issue 11 SPEC. ISS , 2004 , Pages 2153-2163 ; 01651684 (ISSN) Dianat, R ; Marvasti, F ; Azmi, P ; Talebi, S ; Sharif University of Technology

Elsevier 2004

Abstract

In this paper, new vector quantization (VQ) based techniques for reducing the effect of channel noise in image transmission are introduced. In one of the proposed methods, i.e., component VQ (CVQ), by transmitting the components of code-vectors (and not their indices), we will be able to reduce the effect of channel noise. To decrease the output rate of CVQ, a modification of CVQ called sub-index VQ (SIVQ) is introduced. This method has error-correcting capability as well. Simulation results show that CVQ and SIVQ techniques are robust to channel errors and surpass the conventional method, in which the indices of the selected code-vectors are protected using a Reed-Solomon code. An error...