OTHERS_CITABLE
Decision Feedback Channel Estimation for Alamouti Coded OFDM Systems
In this paper, we propose a new channel estimation algorithm for Orthogonal Frequency Division Multiplexing (OFDM) systems, which is extended to the Alamouti Coded OFDM case by extracting required equations. At the first stage of this algorithm, the channel response is estimated for pilot sub-carriers and then, the channel response for data sub-carriers is interpolated by Gaussian Radial Basis Function Network as it is an efficient nonlinear interpolator. The post-processing and filtering on the estimated channel taps energy are proposed to improve the estimation performance and reduce the noise effects of primary estimation, which is caused by LS estimation at pilot data. At next step, the accuracy of our channel estimation algorithm is improved by using iterative decision feedback. The decision feedback method is used to update channel parameters in each OFDM symbol. The effectiveness of proposed techniques is demonstrated through the simulation of OFDM and an Alamouti coded OFDM system with two-transmit and two-receive antennas. Finally, the results are analyzed and compared with previous conventional estimation algorithms. Simulation results show that the proposed algorithms achieve efficient performance in many practical situations.
http://ijict.itrc.ac.ir/article-1-175-en.pdf
2018-10-09
1
11
channel estimation
Alamouti coded OFDM
RBF network
Masoud
Hoseinzade
1
AUTHOR
Kamal
Mohamedpour
2
AUTHOR
Seyed Mehdi
Hosseini Andargoli
3
AUTHOR
OTHERS_CITABLE
Image Encryption Using Tent Chaotic Map and Arnold Cat Map
In this paper, a new algorithm for image encryption using chaotic tent map and Arnold cat map is proposed. This algorithm consists of two major phases, permutation and substitution. In the permutation phase, Arnold cat transform is used. A pseudo random image is produced using the chaotic tent map. In the substitution phase, the permuted image is Exclusively ORed to this pseudo random image in order to generate encrypted images. A computer simulation is used to evaluate the proposed algorithm and to compare its results to encrypted images of other methods. The criteria for these comparisons are chi-square test of histogram, correlation coefficients of pixels, NPCR (number of pixel change rate), UACI (unified average changing intensity), MSE (mean square error) and MAE (mean absolute error). These comparisons show that the proposed chaotic image encryption method has a high performance and security.
http://ijict.itrc.ac.ir/article-1-176-en.pdf
2018-10-09
13
19
Image encryption
Permutation
Substitution
Arnold Cat map
Chaotic Tent map
Elham
Hasani
1
AUTHOR
Mohammad
Eshghi
2
AUTHOR
OTHERS_CITABLE
A Multi-Dimensional Recommendation Framework for Learning Material by Naive Bayes Classifier
Personal Learning Environment (PLE) solutions can empower learners to design ICT environments for their activities in different learning contexts. Recommender systems have been used for supporting learners in PLEbased activities. Since, in the current recommendation approaches, multidimensional attributes of resource and dynamic interests and multi-preference of learners are not fully considered simultaneously, this paper proposes a novel resource recommendation framework in order to personalize learning environments. Learner Tree (LT) is introduced to take into account the multidimensional attributes of resources and learners' rating matrix simultaneously. In addition, a forgetting function also is used to reflect dynamic preference of a learner and a Bayesian classifier is used to predict rate of unrated resources. The main contribution of this paper is proposing a multidimensional data model to consider multi-preference of learner and using naive Bayes classifier to improve the quality of recommendation in the terms of precision, recall and also intra-list similarity. In addition, the proposed approach tries to satisfy the learner’s real learning preference accurately according to the real-time up dated contextual information.
http://ijict.itrc.ac.ir/article-1-177-en.pdf
2018-10-09
21
31
Adaptive recommendation
Multidimensional recommendation
Learning resource
e-Learning
Collaborative filtering
Mojtaba
Salehi
1
AUTHOR
Isa
Nakhai Kamalabadi
2
AUTHOR
OTHERS_CITABLE
Forgery Attack is a Piece of Cake on a Class of Mutual Authentication Protocols
A suitable mutual authentication protocol for an RFID system should provide mutual authentication along with user privacy. In addition, such protocol must be resistant to active and passive attacks, e.g. man-in-the-middle attack, replay attack, reader-/tag-impersonation attack, denial of service attack and traceability attack. Among them, tag-impersonation attack refers to a forgery attack in which the adversary fools the legitimate reader to authenticate it as a valid tag. In this paper we exam the security of three RFID mutual authentication protocols which have been recently proposed by Luo et al., Shen et al. and Habibi and Gardeshi, under tag impersonation attack. We found that these three protocols share a same vulnerability – in each session, the tag and the reader generate a random value respectively and they use the exclusive-or (XOR) of those random values in the authentication process. We exploit this vulnerability to present effective and efficient tag impersonation attacks against these protocols, e.g., the success probabilities of our attacks are “1” and the complexity is at most two runs of each protocol. In addition, we exhibit the improved version of these protocols, which are immune from tag impersonation attacks.
http://ijict.itrc.ac.ir/article-1-178-en.pdf
2018-10-09
33
43
RFID
Authentication
Tag Impersonation
WG-7
ARAP
Nasour
Bagheri
1
AUTHOR
Masoumeh
Safkhani
2
AUTHOR
Majid
Naderi
3
AUTHOR
Yiyuan
Luo
4
AUTHOR
Qi
Chai
5
AUTHOR
OTHERS_CITABLE
Cyber Attack Simulation for Operational Security Evaluation Using Coloured Petri Nets
Today, cyber attacks to computer networks have turned into a real challenge for network administrators. A wide range of methods have been used for attack modeling and security quantification. The most important drawback of the existing methods is that they are not based on real security-related information of networks. Our aim has been to overcome this drawback by using high-level modeling techniques and real security relevant information of systems. In this paper, we use coloured Petri nets (CPNs) for attack modeling. One of the objectives of this paper is to show the power and flexibility of CPNs for high-level attack modeling. In our work, the important elements of networks involved in cyber attacks, such as hosts, attackers, intrusion detection and prevention systems, servers and firewalls are modeled as reusable CPN sub-models. In other words, with the help of hierarchy and the abstraction provided by CPNs, we have proposed a framework for modeling and evaluation of the impacts of cyber attacks on networks. Through an illustrative example, we have modeled a sample network and some attack scenarios by using the security-relevant information extracted from open source vulnerability database (OSVDB). Finally, we have evaluated some security measures of a sample network.
http://ijict.itrc.ac.ir/article-1-179-en.pdf
2018-10-09
45
58
Cyber attacks
attack modeling
coloured Petri nets (CPNs)
availability evaluation
simulation
CPN Tools
Mehrdad
Ashtiani
1
AUTHOR
Mohammad
Abdollahi Azgomi
2
AUTHOR
OTHERS_CITABLE
All Optical Logic Gates: A Tutorial
In this paper we describe the performances of different kinds of all-optical logic gates reported up to now. We introduce all-optical logic gates based on semiconductor optical amplifiers such as ultrahigh speed logic gates exploiting four-wave mixing, cross gain modulation, cross phase modulation, and cross polarization modulation. We demonstrate the performances of all-optical logic gates using delayed interferometers, such as all-optical gates based on Mach-Zehnder and nonlinear loop mirror interferometers. We describe the performances of semiconductor based microring resonator logic gates, such as all-optical logic gates based on nonlinear photonic crystal, couplers and waveguides, lasers and cavities. We illustrate optical gates based on electro-absorption modulator, nonlinear fibers, nanoslabs, and optical thyristor. We introduce molecular logic gates and logic gates based on thermal lens effects.
http://ijict.itrc.ac.ir/article-1-180-en.pdf
2018-10-09
65
98
Optical logic Gates
Photonic Crystals
molecular logic gates
Thermal Lens effect
MEMS
Fatemeh
Davoodi
1
AUTHOR
Nosrat
Granpayeh
2
AUTHOR
OTHERS_CITABLE
A Visual Tracking Algorithm Based on CAMShift and Motion Segmentation
Continuously adaptive mean-shift (CAMShift) is an efficient and light-weight tracking algorithm firstly developed based on mean-shift to track human face in a perceptual user interface. CAMShift tracks a target by searching for the most similar areas to the target region in frames of a video sequence in regard to its reference color histogram. While color based CAMShift is suitable for tracking targets in simple cases, it fails to track objects in more complex situations. In this paper we review our low cost extension to improve the traditional CAMShift algorithm. Combining the original algorithm with simple motion segmentation techniques, we proposed an improved CAMShift algorithm to cope with CAMShift`s tracking problems. We have evaluated the efficiency of our approach through analyzing our tracking results. We have compared our results with other tracking algorithms in various tracking scenarios.
http://ijict.itrc.ac.ir/article-1-181-en.pdf
2018-10-09
99
106
Target tracking
CAMShift
motion segmentation
mean-shift
probability distribution image
Ebrahim
Emami
1
AUTHOR
Mahmood
Fathy
2
AUTHOR
OTHERS_CITABLE
Improving the Quality of Service in the VANET by Detecting and Removing Unused Messages
in the past, traffic safety was addressed by traffic awareness and passive safety measures like solid chassis, seat belts, air bags and etc. Thanks to the ongoing progresses in the concept of vehicular ad hoc networks (VANET), propitious conditions for finding efficient solutions for traffic safety are meeting. Safety messaging is the most important aspect of VANETs where the passive safety (accident readiness) in vehicles was reinforced with the idea of active safety (accident prevention). In safety messaging vehicles message each other over wireless media and update each other on traffic conditions and hazards. Owing to the importance of the QOS in safety messaging, many researchers have focused on this topic. Earlier related works have scrutinized the aspect of increasing the service rate by changing the properties and parameters of scheduler algorithms but this paper with a new look at the issue of quality of service tries to increase the performance of VANET by removing the useless or unused packets.
http://ijict.itrc.ac.ir/article-1-182-en.pdf
2018-10-09
107
112
VANET
Safety message
Service ratio
unused messages
Mohammad Javad
Sayadi
1
AUTHOR
Mahmood
Fathy
2
AUTHOR
Leili
Mahaki
3
AUTHOR