Machine-to-Machine (M2M) communications have been introduced to improve the communication capacit... more Machine-to-Machine (M2M) communications have been introduced to improve the communication capacity in dense wireless networks. One of the most important concerns for network designers is maintaining the high performance of the network when the quality of connections between sources and their destinations is poor. Thus the careful selection of relays between data sources and their destinations is a very important issue. The possibility of simultaneous use of different Radio Frequency (RF) interfaces for transmitting data, which communication devices are equipped with them, can increase the capacity of data transmission over the network. In this paper, two novel M2M relay selection algorithms are proposed, named as Optimal Relay Selection Algorithm (ORSA) and Matching based Relay Selection Algorithm (MRSA). ORSA is a centralized algorithm for the optimal selection of relays by transforming the main problem to a k-cardinality assignment problem that can be solved using the Hungarian al...
2019 27th Iranian Conference on Electrical Engineering (ICEE), 2019
Energy distribution to get more lifetime and noninterfering multipath are two major challenges in... more Energy distribution to get more lifetime and noninterfering multipath are two major challenges in Wireless Multimedia Sensor Networks (WMSNs) routing. The Greedy Perimeter Stateless Routing (GPSR) is a simple routing protocol which uses minimum geographic distance to forward packets toward sink node. However it does not consider energy level and uses single path. Geographic energy-aware non-interfering multipath Routing (GEAM) overcomes this problem by multipath routing and energy consideration, but keeping state of the multiple non-interfering areas has an overhead. In our proposed routing protocol which is called Energy Aware Greedy Stateless Geographic Routing (EAGSGR) we will introduce two path routing without interference only by using two strategic areas. We meanwhile introduce a simple way to deal with the dead end nodes and clusters problem. EAGSGR showed a better performance compared to GPSR and GEAM in terms of QoS parameters such as end-to-end delay, average hop count, energy distribution and packet delivery ratio.
AEU - International Journal of Electronics and Communications, 2008
ABSTRACT Feed-forward is one of the main methods for linearization of microwave power amplifiers.... more ABSTRACT Feed-forward is one of the main methods for linearization of microwave power amplifiers. Although the complexity of the system is increased, the level of inter-modulation rejection (IMR) of a feed-forward system can be improved using a multi-loop configuration. Predicting the IMR of such a system is of prime importance. A new analytical approach in modeling a multi-loop feed-forward system for predicting the linearization performance of the system is presented. The first loop of the multi-loop system is substituted by an equivalent amplifier model and then the reduced system as a new feed-forward system is evaluated. The predicted IMR values are verified using the ADS simulator and a MATLAB program.
Many applications which run on the Internet-ofThings machines require similar bandwidths. These m... more Many applications which run on the Internet-ofThings machines require similar bandwidths. These machines are equipped with multiple Radio Frequency(RF) interfaces for machine-to-machine or machine-to-Base Station(BS) communications. Joint dynamic optimal RF interface setting and nexthop selection in data transmission can maximize the network data rate. For this purpose, we propose a generalized framework for simultaneous selection of these components according to the required bandwidth of machines. This framework is suitable for networks with multiple BSs and sources with similar bandwidth requests. Simulation results show that using the proposed framework, the average data rate of network sources increases up to 117%.
2014 11th International ISC Conference on Information Security and Cryptology, 2014
ABSTRACT The ever-increasing use of trust and reputation models has posed new challenges in distr... more ABSTRACT The ever-increasing use of trust and reputation models has posed new challenges in distributed environments. One of these challenges is the computation of trust while preserving privacy of feedback providers. This is because of the fact that some people may report a dishonest value due to social pressure or fear of the consequences. In this paper, we propose a privacy-preserving collusion-resistant multi-party trust computation scheme which uses data perturbation and homomorphic encryption to preserve the privacy of feedbacks. Our scheme is consisted of two protocols for private summation (S-protocol) and inner product (P-protocol). Our protocols are resistant to collusion of up to m+1 and m+2 agents, respectively, where m is a configurable parameter. In addition, their computational complexities are O(nm) and O(n(m+h)), respectively, where n is the number of agents and h is the homomorphic encryption algorithm complexity. We compare our protocols with related works and show its superiority in terms of collusion-resilience probability as well as complexity.
Machine-to-Machine (M2M) communications have been introduced to improve the communication capacit... more Machine-to-Machine (M2M) communications have been introduced to improve the communication capacity in dense wireless networks. One of the most important concerns for network designers is maintaining the high performance of the network when the quality of connections between sources and their destinations is poor. Thus the careful selection of relays between data sources and their destinations is a very important issue. The possibility of simultaneous use of different Radio Frequency (RF) interfaces for transmitting data, which communication devices are equipped with them, can increase the capacity of data transmission over the network. In this paper, two novel M2M relay selection algorithms are proposed, named as Optimal Relay Selection Algorithm (ORSA) and Matching based Relay Selection Algorithm (MRSA). ORSA is a centralized algorithm for the optimal selection of relays by transforming the main problem to a k-cardinality assignment problem that can be solved using the Hungarian al...
Machine-to-Machine (M2M) communications have been introduced to improve the communication capacit... more Machine-to-Machine (M2M) communications have been introduced to improve the communication capacity in dense wireless networks. One of the most important concerns for network designers is maintaining the high performance of the network when the quality of connections between sources and their destinations is poor. Thus the careful selection of relays between data sources and their destinations is a very important issue. The possibility of simultaneous use of different Radio Frequency (RF) interfaces for transmitting data, which communication devices are equipped with them, can increase the capacity of data transmission over the network. In this paper, two novel M2M relay selection algorithms are proposed, named as Optimal Relay Selection Algorithm (ORSA) and Matching based Relay Selection Algorithm (MRSA). ORSA is a centralized algorithm for the optimal selection of relays by transforming the main problem to a k-cardinality assignment problem that can be solved using the Hungarian al...
Machine to machine communication is one of the main communications in the Internet of Things. How... more Machine to machine communication is one of the main communications in the Internet of Things. How to send data in these highdensity communications using relay selection can help better performance of this type of communications in various applications. In addition, the possibility of simultaneous use of different Radio Frequency (RF) interfaces helps to make better use of the network radio frequencies. Therefore, in this work, we try to further use of machine communication equipment and improve the average data rate of networks in different applications such as the Internet of Things, which have different bandwidth requirements, by providing an optimization algorithm for relay selection as well as the simultaneous and dynamic multiple M2M RF interfaces setting that called Dynamic Optimal Relay Selection and RF interfaces Setting Algorithm (DORSA). The simulation results show that the average DORSA_W-B-Z data rate is improved by 0.8 to 10% compared to the studied algorithms such as d...
Machine-to-Machine (M2M) communications play a significant role in the Internet of Things (IoT). ... more Machine-to-Machine (M2M) communications play a significant role in the Internet of Things (IoT). Cooperation of machines in M2M communications can improve network performance when the quality of connections between sources and their destinations is poor. Careful selection of machines as relays can play an effective role in improving the quality of communication in dense networks. Furthermore, the possibility of simultaneous use of different Radio Frequency (RF) interfaces can increase the capacity of data transmission over the network. In this paper, two novel M2M relay selection algorithms are proposed namely Optimal Relay Selection Algorithm (ORSA) and Matching based Relay Selection Algorithm (MRSA). ORSA is a centralized algorithm that transforms the relay selection problem to a k-cardinality assignment problem that can be solved using the Hungarian algorithm. MRSA is a decentralized algorithm that leverages concepts from matching theory to provide a stable relay assignment. In b...
Various applications of machines in Internet of Things require different bandwidths. Each machine... more Various applications of machines in Internet of Things require different bandwidths. Each machine may choose its RF interface in machine-to-machines or machine-to-base stations communications according to required bandwidth. We propose an optimal next-hop selection framework with a dynamic RF interface setting for sources with the same requested bandwidth. This framework enables machines to optimally select network devices with different RF equipment. In this way, the efficient use of RF network resources can be improved. The simulations show that the average data rate of sources improved between 11.1% to 117%, and the average unmatched source number improved between 1.9% and 5.3%.
Various applications which run on the machines in a network such as Internet-of-Things require di... more Various applications which run on the machines in a network such as Internet-of-Things require different bandwidths. So each machine may select one of its multiple Radio Frequency (RF) interfaces for machine-to-machine or machineto base-station communications according to required bandwidth. We have proposed a generalized framework for joint dynamic optimal RF interface setting and next-hop selection, which is suitable for networks with multiple base stations, and source nodes that have the same requests for bandwidth. Simulation results show average data rate of the source nodes may be increased up to 117%.
Spectrum sensing is the basic step in cognitive radio networks. Its accuracy directly affects spe... more Spectrum sensing is the basic step in cognitive radio networks. Its accuracy directly affects spectrum utilization. In this paper we propose a new method for blind cooperative spectrum sensing using spatial information. We model our sensing matrix as a graph, taking advantage of signal and spatial correlation of antennas. We prove that the general settings of the problem are hard to approximate. Taking spatial information into account, we propose a new scheme to find white space subregions. Cognitive radio users residing in the region may be able to transmit, but must keep their transmission power to the extent that no interference is caused to primary receivers out of the region.
Machine-to-Machine (M2M) communication is one of the main communications in the Internet of Thing... more Machine-to-Machine (M2M) communication is one of the main communications in the Internet of Things (IoT). How to send data in these high-density communications using relay selection can help better performance of this type of communications in various applications. In addition, the possibility of simultaneous use of different Radio Frequency (RF) interfaces helps to make better use of the network radio frequencies. Therefore, in this work, we try to further use of machine communication equipment and improve the average data rate of networks in different applications such as the Internet of Things, which have different bandwidth requirements, by providing an optimization algorithm for relay selection as well as the simultaneous and dynamic multiple M2M RF interfaces setting that called Dynamic Optimal Relay Selection and RF interfaces Setting Algorithm (DORSA). The simulation results show that the average DORSA\_W-B-Z data rate is improved by 0.8 to 10% compared to the studied algori...
Machine-to-Machine (M2M) communications have been introduced to improve the communication capacit... more Machine-to-Machine (M2M) communications have been introduced to improve the communication capacity in dense wireless networks. One of the most important concerns for network designers is maintaining the high performance of the network when the quality of connections between sources and their destinations is poor. Thus the careful selection of relays between data sources and their destinations is a very important issue. The possibility of simultaneous use of different Radio Frequency (RF) interfaces for transmitting data, which communication devices are equipped with them, can increase the capacity of data transmission over the network. In this paper, two novel M2M relay selection algorithms are proposed, named as Optimal Relay Selection Algorithm (ORSA) and Matching based Relay Selection Algorithm (MRSA). ORSA is a centralized algorithm for the optimal selection of relays by transforming the main problem to a k-cardinality assignment problem that can be solved using the Hungarian al...
2019 27th Iranian Conference on Electrical Engineering (ICEE), 2019
Energy distribution to get more lifetime and noninterfering multipath are two major challenges in... more Energy distribution to get more lifetime and noninterfering multipath are two major challenges in Wireless Multimedia Sensor Networks (WMSNs) routing. The Greedy Perimeter Stateless Routing (GPSR) is a simple routing protocol which uses minimum geographic distance to forward packets toward sink node. However it does not consider energy level and uses single path. Geographic energy-aware non-interfering multipath Routing (GEAM) overcomes this problem by multipath routing and energy consideration, but keeping state of the multiple non-interfering areas has an overhead. In our proposed routing protocol which is called Energy Aware Greedy Stateless Geographic Routing (EAGSGR) we will introduce two path routing without interference only by using two strategic areas. We meanwhile introduce a simple way to deal with the dead end nodes and clusters problem. EAGSGR showed a better performance compared to GPSR and GEAM in terms of QoS parameters such as end-to-end delay, average hop count, energy distribution and packet delivery ratio.
AEU - International Journal of Electronics and Communications, 2008
ABSTRACT Feed-forward is one of the main methods for linearization of microwave power amplifiers.... more ABSTRACT Feed-forward is one of the main methods for linearization of microwave power amplifiers. Although the complexity of the system is increased, the level of inter-modulation rejection (IMR) of a feed-forward system can be improved using a multi-loop configuration. Predicting the IMR of such a system is of prime importance. A new analytical approach in modeling a multi-loop feed-forward system for predicting the linearization performance of the system is presented. The first loop of the multi-loop system is substituted by an equivalent amplifier model and then the reduced system as a new feed-forward system is evaluated. The predicted IMR values are verified using the ADS simulator and a MATLAB program.
Many applications which run on the Internet-ofThings machines require similar bandwidths. These m... more Many applications which run on the Internet-ofThings machines require similar bandwidths. These machines are equipped with multiple Radio Frequency(RF) interfaces for machine-to-machine or machine-to-Base Station(BS) communications. Joint dynamic optimal RF interface setting and nexthop selection in data transmission can maximize the network data rate. For this purpose, we propose a generalized framework for simultaneous selection of these components according to the required bandwidth of machines. This framework is suitable for networks with multiple BSs and sources with similar bandwidth requests. Simulation results show that using the proposed framework, the average data rate of network sources increases up to 117%.
2014 11th International ISC Conference on Information Security and Cryptology, 2014
ABSTRACT The ever-increasing use of trust and reputation models has posed new challenges in distr... more ABSTRACT The ever-increasing use of trust and reputation models has posed new challenges in distributed environments. One of these challenges is the computation of trust while preserving privacy of feedback providers. This is because of the fact that some people may report a dishonest value due to social pressure or fear of the consequences. In this paper, we propose a privacy-preserving collusion-resistant multi-party trust computation scheme which uses data perturbation and homomorphic encryption to preserve the privacy of feedbacks. Our scheme is consisted of two protocols for private summation (S-protocol) and inner product (P-protocol). Our protocols are resistant to collusion of up to m+1 and m+2 agents, respectively, where m is a configurable parameter. In addition, their computational complexities are O(nm) and O(n(m+h)), respectively, where n is the number of agents and h is the homomorphic encryption algorithm complexity. We compare our protocols with related works and show its superiority in terms of collusion-resilience probability as well as complexity.
Machine-to-Machine (M2M) communications have been introduced to improve the communication capacit... more Machine-to-Machine (M2M) communications have been introduced to improve the communication capacity in dense wireless networks. One of the most important concerns for network designers is maintaining the high performance of the network when the quality of connections between sources and their destinations is poor. Thus the careful selection of relays between data sources and their destinations is a very important issue. The possibility of simultaneous use of different Radio Frequency (RF) interfaces for transmitting data, which communication devices are equipped with them, can increase the capacity of data transmission over the network. In this paper, two novel M2M relay selection algorithms are proposed, named as Optimal Relay Selection Algorithm (ORSA) and Matching based Relay Selection Algorithm (MRSA). ORSA is a centralized algorithm for the optimal selection of relays by transforming the main problem to a k-cardinality assignment problem that can be solved using the Hungarian al...
Machine-to-Machine (M2M) communications have been introduced to improve the communication capacit... more Machine-to-Machine (M2M) communications have been introduced to improve the communication capacity in dense wireless networks. One of the most important concerns for network designers is maintaining the high performance of the network when the quality of connections between sources and their destinations is poor. Thus the careful selection of relays between data sources and their destinations is a very important issue. The possibility of simultaneous use of different Radio Frequency (RF) interfaces for transmitting data, which communication devices are equipped with them, can increase the capacity of data transmission over the network. In this paper, two novel M2M relay selection algorithms are proposed, named as Optimal Relay Selection Algorithm (ORSA) and Matching based Relay Selection Algorithm (MRSA). ORSA is a centralized algorithm for the optimal selection of relays by transforming the main problem to a k-cardinality assignment problem that can be solved using the Hungarian al...
Machine to machine communication is one of the main communications in the Internet of Things. How... more Machine to machine communication is one of the main communications in the Internet of Things. How to send data in these highdensity communications using relay selection can help better performance of this type of communications in various applications. In addition, the possibility of simultaneous use of different Radio Frequency (RF) interfaces helps to make better use of the network radio frequencies. Therefore, in this work, we try to further use of machine communication equipment and improve the average data rate of networks in different applications such as the Internet of Things, which have different bandwidth requirements, by providing an optimization algorithm for relay selection as well as the simultaneous and dynamic multiple M2M RF interfaces setting that called Dynamic Optimal Relay Selection and RF interfaces Setting Algorithm (DORSA). The simulation results show that the average DORSA_W-B-Z data rate is improved by 0.8 to 10% compared to the studied algorithms such as d...
Machine-to-Machine (M2M) communications play a significant role in the Internet of Things (IoT). ... more Machine-to-Machine (M2M) communications play a significant role in the Internet of Things (IoT). Cooperation of machines in M2M communications can improve network performance when the quality of connections between sources and their destinations is poor. Careful selection of machines as relays can play an effective role in improving the quality of communication in dense networks. Furthermore, the possibility of simultaneous use of different Radio Frequency (RF) interfaces can increase the capacity of data transmission over the network. In this paper, two novel M2M relay selection algorithms are proposed namely Optimal Relay Selection Algorithm (ORSA) and Matching based Relay Selection Algorithm (MRSA). ORSA is a centralized algorithm that transforms the relay selection problem to a k-cardinality assignment problem that can be solved using the Hungarian algorithm. MRSA is a decentralized algorithm that leverages concepts from matching theory to provide a stable relay assignment. In b...
Various applications of machines in Internet of Things require different bandwidths. Each machine... more Various applications of machines in Internet of Things require different bandwidths. Each machine may choose its RF interface in machine-to-machines or machine-to-base stations communications according to required bandwidth. We propose an optimal next-hop selection framework with a dynamic RF interface setting for sources with the same requested bandwidth. This framework enables machines to optimally select network devices with different RF equipment. In this way, the efficient use of RF network resources can be improved. The simulations show that the average data rate of sources improved between 11.1% to 117%, and the average unmatched source number improved between 1.9% and 5.3%.
Various applications which run on the machines in a network such as Internet-of-Things require di... more Various applications which run on the machines in a network such as Internet-of-Things require different bandwidths. So each machine may select one of its multiple Radio Frequency (RF) interfaces for machine-to-machine or machineto base-station communications according to required bandwidth. We have proposed a generalized framework for joint dynamic optimal RF interface setting and next-hop selection, which is suitable for networks with multiple base stations, and source nodes that have the same requests for bandwidth. Simulation results show average data rate of the source nodes may be increased up to 117%.
Spectrum sensing is the basic step in cognitive radio networks. Its accuracy directly affects spe... more Spectrum sensing is the basic step in cognitive radio networks. Its accuracy directly affects spectrum utilization. In this paper we propose a new method for blind cooperative spectrum sensing using spatial information. We model our sensing matrix as a graph, taking advantage of signal and spatial correlation of antennas. We prove that the general settings of the problem are hard to approximate. Taking spatial information into account, we propose a new scheme to find white space subregions. Cognitive radio users residing in the region may be able to transmit, but must keep their transmission power to the extent that no interference is caused to primary receivers out of the region.
Machine-to-Machine (M2M) communication is one of the main communications in the Internet of Thing... more Machine-to-Machine (M2M) communication is one of the main communications in the Internet of Things (IoT). How to send data in these high-density communications using relay selection can help better performance of this type of communications in various applications. In addition, the possibility of simultaneous use of different Radio Frequency (RF) interfaces helps to make better use of the network radio frequencies. Therefore, in this work, we try to further use of machine communication equipment and improve the average data rate of networks in different applications such as the Internet of Things, which have different bandwidth requirements, by providing an optimization algorithm for relay selection as well as the simultaneous and dynamic multiple M2M RF interfaces setting that called Dynamic Optimal Relay Selection and RF interfaces Setting Algorithm (DORSA). The simulation results show that the average DORSA\_W-B-Z data rate is improved by 0.8 to 10% compared to the studied algori...
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Papers by Ali Mohammad Afshin Hemmatyar