ICT Research Institute(ITRC)
International Journal of Information and Communication Technology Research
2251-6107
2783-4425
1
3
2009
9
1
A Backup Routing Scheme for Mobile Ad-Hoc Networks
1
13
EN
Amir
Esmailpour
Department of Computing and Information Science University of Guelph Guelph, Canada NlG 2Wl
Y
Nidal
Nasser
Department of Computing and Information Science University of Guelph Guelph, Canada NlG 2Wl
N
In recent years, performance of the Mobile Ad-Hoc Network (MANET) has become an important research area in the wireless networks community. MANET consists of clusters of Mobile Nodes (MNs) on the access network that could be connected to other clusters through a fixed backbone of routers. The access link contention can severely constrain the end-to-end throughput of the path between a pair of source and destination MNs connected through the backbone. In this paper, we propose an integrated routing system for MANET that includes the backbone paths and the ad-hoc paths formed as a result of direct communication among MNs without going through the backbone. In our proposed routing system, an alternative ad-hoc path can be used only when the primary backbone path is severely constrained due to access links contention. We also propose a scheme for making the MN aware of link quality measures, and incorporate throughput metric in the core of AODV. We implemented the proposed routing system in the OPNET simulator, and evaluated the performance of our scheme under a variety of conditions. Simulation results show that the alternative ad-hoc path is effective in delivering higher throughput when the backbone path is severely constrained.
MANET, Wireless Mesh Network (WMN), On-demand routing, Link-state routing
http://ijict.itrc.ac.ir/article-1-281-en.html
http://ijict.itrc.ac.ir/article-1-281-en.pdf
ICT Research Institute(ITRC)
International Journal of Information and Communication Technology Research
2251-6107
2783-4425
1
3
2009
9
1
Designing and Developing a Wordnet for Persian Nouns Pages
1
13
EN
Akbar
Ehsani
Faculty of Foreign Languages and Literatures,Allameh Tabataba'i University ,Tehran,Iran
Y
Seyed Mostafa
Asi
Institute for Humanities and Cultural Studies,Tehran,Iran
N
Mehrnoush
Shamsfard
Department of Electrical and Computer Engineering,Shahid Beheshti University,Tehran,Iran
N
Mahsa
Arab Yarmohammadi
Department of Electrical and Computer Engineering,Shahid Beheshti University,Tehran,Iran
N
This paper discusses the process of designing and developing the Persian noun Wordnet as an important tool for natural language processing. First, an introduction to the most significant projects for building WordNets around the world and their prominent features and applications is provided. Then different stages of designing and developing of Persian noun WordNet including editor, building process and language resources will be discussed. At the end, we will show the capability of connecting the developed noun Wordnet to other Persian WordNets (adjective and verb WordNets) and the WordNets of other languages.
Persian WordNets, natural language processing, Computer linguistics
http://ijict.itrc.ac.ir/article-1-286-en.html
http://ijict.itrc.ac.ir/article-1-286-en.pdf
ICT Research Institute(ITRC)
International Journal of Information and Communication Technology Research
2251-6107
2783-4425
1
3
2009
9
1
Characterization of Wireless Mesh Backhaul Networks with MIMO Systems
15
26
EN
Navin
Haghighizadeh
Microwave/mm-wave & Wireless Communications Research Laboratory Department of Electrical Engineering Amirkabir University of Technology, Tehran, Iran
Y
Abbas
Mohammadi
Microwave/mm-wave & Wireless Communications Research Laboratory Department of Electrical Engineering Amirkabir University of Technology, Tehran, Iran
N
In this paper, a wireless mesh backhaul using MIMO systems has been studied. In the mesh networking, information is routed from source to destination over multiple wireless links. On the other hand, using wireless MIMO systems, the channel capacity is significantly increased without additional signal power or bandwidth. We have used the linear programming to optimize the routing determination to maximize the throughput. This technique is used to calculate the throughput for a hexagonal grid of base-stations, for single-hop, multi-hop, SISO, and MIMO transmissions for various network scenarios.
Mesh networking, MIMO, Throughput, Multihop, Mobile Backhaul, Wireless backhaul
http://ijict.itrc.ac.ir/article-1-282-en.html
http://ijict.itrc.ac.ir/article-1-282-en.pdf
ICT Research Institute(ITRC)
International Journal of Information and Communication Technology Research
2251-6107
2783-4425
1
3
2009
9
1
Corpus-Based Analysis for Multi-Token Units in Persian
15
26
EN
Masoud
Sharifi Atashgah
Department of Literature and Human Science University,Tehran University,Tehran,Iran
Y
Mahmoud
Bijankhan
Department of Literature and Human Science University,Tehran University,Tehran,Iran
N
Because of the joining behavior of Persian script and its orthographic variation, the morphological and syntactic annotations of multi-token units meet various issues. By the analysis of Perso-Arabic script and its problems, the various collocation types of the tokens including the compositional, non-compositional and the new semicompositional constructions are described in the present paper. Then, to illustrate these constructions, the static and dynamic multi-token units will be presented for the generative and non-generative structures of the main categories including the verbs, infinitives, prepositions, conjunctions, adverbs, adjectives and nouns. Defining the multi-token unit templates for these categories is one of the important results of this research. The findings can be input to the segmentation module of the Persian Treebank generator system. The other usage of the present research is in the design and implementation of the morphological analyzers and syntactical parsers.
Persian script, orthographic variation, morphological and syntactic annotations, Persian Treebank generator system, syntactical parsers, morphological analyzers
http://ijict.itrc.ac.ir/article-1-287-en.html
http://ijict.itrc.ac.ir/article-1-287-en.pdf
ICT Research Institute(ITRC)
International Journal of Information and Communication Technology Research
2251-6107
2783-4425
1
3
2009
9
1
A Novel Still Image Error Concealment Using Fragile Watermarking in Wireless Image , Transmission and Packet-Switched Networks
23
34
EN
Davood
Bashiri
Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran
Y
Ali
Aghagolzadeh
Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran
N
Javad
Musevi niya
Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran
N
Mahdi
Nooshyar
Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz, Iran
N
In this paper, we propose a new error concealment method for covering up the high packet losses of an original image after its transmission through an error-prone channel. Our proposed technique utilizes, Discrete Wavelet Transform (DWT) to produce a lower resolution copy of the original image. Then we embed some o'f discrete cosine transform (DCT) coefficients of this downsized replica of the original image into the original image in the spatial (pixel) domain inside macroblocks (MBs) as a watermark. This technique can be implemented for error-prone channels to combat degradations due to packets loss in a backward-compatible scheme.
Error-prone channels, Watermarking, Error concealment
http://ijict.itrc.ac.ir/article-1-283-en.html
http://ijict.itrc.ac.ir/article-1-283-en.pdf
ICT Research Institute(ITRC)
International Journal of Information and Communication Technology Research
2251-6107
2783-4425
1
3
2009
9
1
A Reliable Transport Protocol for Wireless Sensor Networks
35
43
EN
Mohammad Hossien
Yaghmaee Moghaddam
Computer Deparetment, Ferdowsi University of Mashhad, Mashhad,Iran
Y
Donald
Adjeroh
Lane Department of Electrical Engineering, West Virginia University
N
Designing a reliable transport protocol is a new challenging area in Wireless Sensor Networks (WSNs). Traditional transport layer protocols (such as TCP and UDP) can't directly be applied to the WSNs. Generally transport layer is responsible for congestion control and reliable packet delivery. Congestion is an essential problem in WSNs. It not only wastes the scarce energy due to a large number of retransmissions and packet drops, but also hampers the event detection reliability. Thus, to meet the Quality of Service (QoS) requirements of network applications, a reliable and fair transport protocol is mandatory. In this paper we present a reliable transport protocol for wireless sensor networks which not only controls the congestion in the network, but also provides reliability in packet delivery. The proposed model uses a rate control mechanism to adjust the transmission rate of each sensor node based on the congestion degree in the network. We use the time to recover packet loss as a congestion indicator. To use a node's energy efficiently, we use a hop-by-hop NACK based reliability guaranty model. Simulation results, confirm the superiority of the proposed model.
Wireless Sensor Networks, Congestion Control, Reliability, Transport Protocols, Rate based control
http://ijict.itrc.ac.ir/article-1-284-en.html
http://ijict.itrc.ac.ir/article-1-284-en.pdf
ICT Research Institute(ITRC)
International Journal of Information and Communication Technology Research
2251-6107
2783-4425
1
3
2009
9
1
Performance Analysis of Zero Crossing DPLL with Linearized Phase Detector
45
51
EN
Qassim
Nasir
Department of Electrical and Computer Engineering University of Sharjah Sharjah , UAE
Y
Saleh
AI-Araji
Communication Engineering Department Khalifa University of Science, Technology and Research Sharjah , UAE
N
This work introduces a new structure of Zero Crossing Digital Phase Locked Loop with Arc Sine block (ASZCDPLL) to linearize the phase difference detection, and enhance the loop performance. The new loop has faster acquisition, less steady state phase error, and wider locking range as compared to the conventional ZCDPLL. The locking range improvement and faster acquisition have been confirmed through simulation. The loop has been implemented and tested in real time using Texas Instruments TMS320C6416 DSP development kit.
non-uniform sampling, digital phase locked loops, zero crossing DPLL
http://ijict.itrc.ac.ir/article-1-285-en.html
http://ijict.itrc.ac.ir/article-1-285-en.pdf