SeyedReza Taghizadeh | University of Tehran (original) (raw)
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Papers by SeyedReza Taghizadeh
IEEE Access Journal, 2018
The IPv6 routing protocol for low power and lossy networks (RPL) was accepted as the standard ro... more The IPv6 routing protocol for low power and lossy networks (RPL) was accepted as the standard routing protocol for Internet of Things (IoT) by Internet engineering task force on March 2012. Since then, it has been used in different IoT applications. Though RPL considerably deals with IoT network requirements, there are still some open problems to solve, since it was not initially designed for IoT applications. In this paper, we address the problem of packet loss and power depletion in an RPL-based network under heavy and highly dynamic load. We address this problem in three steps: First, we present a context-aware objective function (CAOF), which computes the rank, considering the context of the node. CAOF also avoids thundering herd phenomenon by gradual shifting from a high rank value toward the real rank value. Second, we present a new routing metric, known as context-aware routing metric (CARF) which considers the status of remaining power and queue utilization of parent chain toward the root in a recursive manner while lessening the effect of upstream parents as it gets farther down the path. Through comprehensive evaluations, we show that this metric leads to a better decision about the proper parent in a network with high traf c dynamicity, rather than deciding merely based on the parent rank. Third, we present a new parent selection mechanism, which selects the best parent based on CARF and some other metrics while avoiding routing loops by a simple yet effective countermeasure. Evaluation results reveal improvements in network lifetime while decreasing packet loss in comparison with standard speci cation of RPL.
Figure 4 : The OpenNebula architecture [17]
Security concerns have given rise to immerging an active area of research due to the many securit... more Security concerns have given rise to immerging an active area of research due to the many security threats that many organizations have faced at present. Addressing these issues requires getting confidence from user for cloud applications and services. In this paper, we have cast light over the major security threats of cloud computing systems, while introducing the most suitable countermeasures for them. We have also cited the aspect to be focused on when talking about cloud security. We have categorized these threats according to different viewpoints, providing a useful and little-known list of threats. After that some effective countermeasures are listed and explained.
A wireless ad hoc network typically refers to any set of wireless networks where all devices have... more A wireless ad hoc network typically refers to any set of wireless networks where all devices have equal status on the network and are free to associate with any other wireless ad hoc network devices in their range. Due to their nature, these networks commonly do not have external power supplies, and each node has a limited internal power source. In this paper, we put forward a new routing protocol that is light enough for energy constrained networks, and find routes on the basis of remaining power of each node. Besides, we have also taken some other factors into consideration. These factors include the ratio of remaining power of a node to the distance of the node from next receiving node and the ratio of the remaining power of current node to the average remaining power of the whole network. This protocol puts emphasis on routing in such a way that the network stays heterogeneous in terms of remaining power of nodes. This homogeneity brings on a longer network lifetime. In addition, the presented protocol does not impose a high computational load on the network. Hence, it is lightweight enough to be used in networks with low computational power and constrained power resources.
In recent years, cloud computing growth has taken all the attention of various communities like r... more In recent years, cloud computing growth has taken all the attention of various communities like researches, internet users, and government organizations. It reduced information technology overhead for the end-user, and total cost of ownership, and brought on greater flexibility, and on demand services. This concept, as a new kind of advanced technology, accelerates the innovation for the computer industry. This concept is based on the Internet, whose task is to ensure that users can simply use the computing resources. Users do not require any special knowledge about the concept of Cloud computing while using it. But before starting to use cloud services, they should choose between many service providers that are available nowadays. On the other hand, in this technologically growing world with lots of service providers and cloud services, it would be a difficult task for a user to choose between service providers. So a sever need of a Service Providers Selection System (SPS System) is felt. In this paper, we have proposed a method to select Service Providers in the best possible way, according to the cloud services that a user wants, and the priority of his/her needs. This selection is done by means of a service provider selection agent.
Wireless Sensor Networks (WSNs) consist of small nodes with sensing, computation, and wireless co... more Wireless Sensor Networks (WSNs) consist of small nodes with sensing, computation, and wireless communications capabilities. Many routing, power management, and data dissemination protocols have been specially designed for WSNs where energy awareness is an essential design issue In this paper, we present a survey of routing techniques in WSNs. We first explain general issues of wireless sensor networks. Then we outline different perspectives on classification of wireless sensor network routing protocols. After that we cite different routing protocols and their features. Some comparison between two or more of them is also shown in form of figures and tables. We also highlight the advantages and disadvantages of each routing technique.
_Steganography is the art of hiding the fact that communication is taking place. Steganographic s... more _Steganography is the art of hiding the fact that communication is taking place. Steganographic systems can hide messages inside images or other digital objects. To a casual observer inspecting these images, the messages are invisible. In this paper we have first explained concept, and also the history of steganography. After that we have mentioned its basis; and as the main part of the paper, we have cited and explained different methods of steganography. We have also tried to mention advantages and disadvantages of them, and also the way each algorithm works.
As a consequence of widespread usage, wireless sensor networks has become a hot topic, and routin... more As a consequence of widespread usage, wireless sensor networks has become a hot topic, and routing issues in wireless sensor networks have attracted many researchers. On of the most importing things in routing protocols is security issue. As a nature of wireless sensor networks, they are prone to many malicious actions. So the routing protocol should be secure enough to guarantee the data security. In this paper, we present a routing protocol, which is secure in both cases of route construction, and data dissemination. We have simulated this protocol using NS2.
IEEE Access Journal, 2018
The IPv6 routing protocol for low power and lossy networks (RPL) was accepted as the standard ro... more The IPv6 routing protocol for low power and lossy networks (RPL) was accepted as the standard routing protocol for Internet of Things (IoT) by Internet engineering task force on March 2012. Since then, it has been used in different IoT applications. Though RPL considerably deals with IoT network requirements, there are still some open problems to solve, since it was not initially designed for IoT applications. In this paper, we address the problem of packet loss and power depletion in an RPL-based network under heavy and highly dynamic load. We address this problem in three steps: First, we present a context-aware objective function (CAOF), which computes the rank, considering the context of the node. CAOF also avoids thundering herd phenomenon by gradual shifting from a high rank value toward the real rank value. Second, we present a new routing metric, known as context-aware routing metric (CARF) which considers the status of remaining power and queue utilization of parent chain toward the root in a recursive manner while lessening the effect of upstream parents as it gets farther down the path. Through comprehensive evaluations, we show that this metric leads to a better decision about the proper parent in a network with high traf c dynamicity, rather than deciding merely based on the parent rank. Third, we present a new parent selection mechanism, which selects the best parent based on CARF and some other metrics while avoiding routing loops by a simple yet effective countermeasure. Evaluation results reveal improvements in network lifetime while decreasing packet loss in comparison with standard speci cation of RPL.
Figure 4 : The OpenNebula architecture [17]
Security concerns have given rise to immerging an active area of research due to the many securit... more Security concerns have given rise to immerging an active area of research due to the many security threats that many organizations have faced at present. Addressing these issues requires getting confidence from user for cloud applications and services. In this paper, we have cast light over the major security threats of cloud computing systems, while introducing the most suitable countermeasures for them. We have also cited the aspect to be focused on when talking about cloud security. We have categorized these threats according to different viewpoints, providing a useful and little-known list of threats. After that some effective countermeasures are listed and explained.
A wireless ad hoc network typically refers to any set of wireless networks where all devices have... more A wireless ad hoc network typically refers to any set of wireless networks where all devices have equal status on the network and are free to associate with any other wireless ad hoc network devices in their range. Due to their nature, these networks commonly do not have external power supplies, and each node has a limited internal power source. In this paper, we put forward a new routing protocol that is light enough for energy constrained networks, and find routes on the basis of remaining power of each node. Besides, we have also taken some other factors into consideration. These factors include the ratio of remaining power of a node to the distance of the node from next receiving node and the ratio of the remaining power of current node to the average remaining power of the whole network. This protocol puts emphasis on routing in such a way that the network stays heterogeneous in terms of remaining power of nodes. This homogeneity brings on a longer network lifetime. In addition, the presented protocol does not impose a high computational load on the network. Hence, it is lightweight enough to be used in networks with low computational power and constrained power resources.
In recent years, cloud computing growth has taken all the attention of various communities like r... more In recent years, cloud computing growth has taken all the attention of various communities like researches, internet users, and government organizations. It reduced information technology overhead for the end-user, and total cost of ownership, and brought on greater flexibility, and on demand services. This concept, as a new kind of advanced technology, accelerates the innovation for the computer industry. This concept is based on the Internet, whose task is to ensure that users can simply use the computing resources. Users do not require any special knowledge about the concept of Cloud computing while using it. But before starting to use cloud services, they should choose between many service providers that are available nowadays. On the other hand, in this technologically growing world with lots of service providers and cloud services, it would be a difficult task for a user to choose between service providers. So a sever need of a Service Providers Selection System (SPS System) is felt. In this paper, we have proposed a method to select Service Providers in the best possible way, according to the cloud services that a user wants, and the priority of his/her needs. This selection is done by means of a service provider selection agent.
Wireless Sensor Networks (WSNs) consist of small nodes with sensing, computation, and wireless co... more Wireless Sensor Networks (WSNs) consist of small nodes with sensing, computation, and wireless communications capabilities. Many routing, power management, and data dissemination protocols have been specially designed for WSNs where energy awareness is an essential design issue In this paper, we present a survey of routing techniques in WSNs. We first explain general issues of wireless sensor networks. Then we outline different perspectives on classification of wireless sensor network routing protocols. After that we cite different routing protocols and their features. Some comparison between two or more of them is also shown in form of figures and tables. We also highlight the advantages and disadvantages of each routing technique.
_Steganography is the art of hiding the fact that communication is taking place. Steganographic s... more _Steganography is the art of hiding the fact that communication is taking place. Steganographic systems can hide messages inside images or other digital objects. To a casual observer inspecting these images, the messages are invisible. In this paper we have first explained concept, and also the history of steganography. After that we have mentioned its basis; and as the main part of the paper, we have cited and explained different methods of steganography. We have also tried to mention advantages and disadvantages of them, and also the way each algorithm works.
As a consequence of widespread usage, wireless sensor networks has become a hot topic, and routin... more As a consequence of widespread usage, wireless sensor networks has become a hot topic, and routing issues in wireless sensor networks have attracted many researchers. On of the most importing things in routing protocols is security issue. As a nature of wireless sensor networks, they are prone to many malicious actions. So the routing protocol should be secure enough to guarantee the data security. In this paper, we present a routing protocol, which is secure in both cases of route construction, and data dissemination. We have simulated this protocol using NS2.