Computer Networks and Distributed Systems
Nafiseh Daneshgar; M. Habibi Najafi; Mohsen Jahanshahi; Ehsan Ahvar
Volume 2, Issue 1 , February 2016, Pages 1-8
Abstract
Energy consumption is considered as a critical issue in wireless sensor networks (WSNs). Batteries of sensor nodes have limited power supply which in turn limits services and applications that can be supported by them. An efcient solution to improve energy consumption and even trafc in WSNs is Data Aggregation ...
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Energy consumption is considered as a critical issue in wireless sensor networks (WSNs). Batteries of sensor nodes have limited power supply which in turn limits services and applications that can be supported by them. An efcient solution to improve energy consumption and even trafc in WSNs is Data Aggregation (DA) that can reduce the number of transmissions. Two main challenges for DA are: (i) most DA techniques need network clustering. Clustering itself is a time and energy consuming procedure. (ii) DA techniques often do not have ability to detect intrusions. Studying to design a new DA technique without using clustering and with ability of nding intrusion is valuable. This paper proposes an energy-intrusion aware DA Technique (named EIDA) that does not need clustering. EIDA is designed to support on demand requests of mobile sinks in WSNs. It uses learning automata for aggregating data and a simple and effective algorithm for intrusion detection. Finally, we simulate
Computer Architecture and Digital Systems
Babak Tavakoli; Mehdi Hosseinzadeh; Somayeh Jassbi
Volume 2, Issue 1 , February 2016, Pages 9-16
Abstract
Residue Number System (RNS) is a non-weighted number system for integer number arithmetic, which is based on the residues of a number to a certain set of numbers called module set. The main characteristics and advantage of residue number system is reducing carry propagation in calculations. The elimination ...
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Residue Number System (RNS) is a non-weighted number system for integer number arithmetic, which is based on the residues of a number to a certain set of numbers called module set. The main characteristics and advantage of residue number system is reducing carry propagation in calculations. The elimination of carry propagation leads to the possibility of maximizing parallel processing and reducing the delay. Residue number system is mostly fitted for calculations involving addition and multiplication. But some calculations and operations such as division, comparison between numbers, sign determination and overflow detection is complicated. In this paper a method for overflow detection is proposed for the special moduli set {2n-1,2n,2n+1} . This moduli set is favorable because of the ease of calculations in forward and reverse conversions. The proposed method is based on grouping the dynamic range into groups by using the New Chinese Theorem and exploiting the properties of residue differences. Each operand of addition is mapped into a group, then the sum of these groups is compared with the indicator and the overflow is detected. The proposed method can detect overflow with less delay comparing to previous methods.
Computer Architecture and Digital Systems
Mehrdad Poorhosseini
Volume 2, Issue 1 , February 2016, Pages 17-26
Abstract
Quantum dot Cellular Automata (QCA) is one of the important nano-level technologies for implementation of both combinational and sequential systems. QCA have the potential to achieve low power dissipation and operate high speed at THZ frequencies. However large probability of occurrence fabrication defects ...
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Quantum dot Cellular Automata (QCA) is one of the important nano-level technologies for implementation of both combinational and sequential systems. QCA have the potential to achieve low power dissipation and operate high speed at THZ frequencies. However large probability of occurrence fabrication defects in QCA, is a fundamental challenge to use this emerging technology. Because of these various defects, it is necessary to obtain exhaustive recognition about these defects. In this paper a complete survey of different QCA faults are presented first. Then some techniques to improve fault tolerance in QCA circuits explained. The effects of missing cell as an important fault on XOR gate that is one of important basic building block in QCA technology is then discussed by exhaustive simulations. Improvement technique is then applied to these XOR structures and then structures are resimulated to measure their fault tolerance improvement due to using these fault tolerance technique. The result show that different QCA XOR gates have different sensitivity against this fault. After using improvement technique, the tolerance of XOR gates have been increased, furthermore in terms of sensitivity against this defect XORs show similar behavior that indicate the effectiveness of improvement have been made.
Computer Networks and Distributed Systems
Mehran Pourmohammad Abdollahi; Javad Musevi Niya; Payman Mahmoudi Biroun
Volume 2, Issue 1 , February 2016, Pages 27-36
Abstract
Designing wireless sensor networks should meet appropriate parameters such as quality of service (QoS) defined by different users. The variable physical conditions of the environment, processing and transmission power limitations and limited communication capabilities are the most important obstacles ...
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Designing wireless sensor networks should meet appropriate parameters such as quality of service (QoS) defined by different users. The variable physical conditions of the environment, processing and transmission power limitations and limited communication capabilities are the most important obstacles that influence QoS parameters such as throughput, delay, reliability and network lifetime. The most important problems that directly have destructive effects on these parameters are hidden and exposed node problems. These problems extremely decrease throughput and increase delay and power consumption in the network. In this paper, we propose a new and efficient method that relies on clustering, grouping and subgrouping strategy to create smaller zones and avoid collisions. By allocating different transmission powers to different nodes depending on their hierarchy level in the network, the mentioned problems decrease and as a result power consumption decreases due to reduction in the retransmissions. This mechanism has been simulated by OPNET on IEEE802.15.4/Zigbee
Computer Architecture and Digital Systems
Ehsan Abbasi
Volume 2, Issue 1 , February 2016, Pages 37-44
Abstract
The studies in aerial vehicles modeling and control have been increased rapidly recently. In this paper , a coordination of two types of heterogeneous robots , namely unmanned aerial vehicle (UAV) and unmanned ground vehicle (UGV) is considered. In this paper the UAV plays the role of a virtual leader ...
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The studies in aerial vehicles modeling and control have been increased rapidly recently. In this paper , a coordination of two types of heterogeneous robots , namely unmanned aerial vehicle (UAV) and unmanned ground vehicle (UGV) is considered. In this paper the UAV plays the role of a virtual leader for the UGVs. The system consists of a vision- based target detection algorithm that uses the color and image moment of a given target. The modeling of the vertical take off and landing vehicle will be described by using Euler - Newton equations. All of flight controller commands are directly generated based on the offset of the target from the image frame. The image processing and intelligent control algorithms such a Kalman filter and so on have been implemented on a latest computer. Matlab Simulink software has been used to test, analyze and compare the performance of the controllers in simulations .
Computer Networks and Distributed Systems
razieh barzegar
Volume 2, Issue 1 , February 2016, Pages 45-52
Abstract
education has stepped to an ultra-place and time in 21st century. We have entered to digital and wireless communication century which mobile technologies have changed the process of education and instruction. The application of these mobile technologies for creation of knowledge, attitude and skill in ...
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education has stepped to an ultra-place and time in 21st century. We have entered to digital and wireless communication century which mobile technologies have changed the process of education and instruction. The application of these mobile technologies for creation of knowledge, attitude and skill in learners is called Mobile Learning. The effectiveness of mobile learning programs requires new communication skills and modern of educational models, this article is written to cover this subject. In this article, first, cover definition of mobile learning, it’s place in distance education, elements, pubic rules, chances and challenges, performance research’s and epitome of future of mobile learning. In continue article, educational approaches will be interpreted and collaboration learning and teacher-center instruction will be inspected as sub collection of these approaches and at the end a modern educational model that has been derived from before approaches, will be suggested for mobile learning. This model is combination of best specifications of behaviorism and constructivism theories in macro level, and teacher-center instruction and collaboration learning in micro level.