Masoud Sabaei

Amirkabir University of Technology | TUS · Department of Computer Engineering and Information Technology

In IEEE 802.15.4 standard for low-power low-range wireless communications, only one channel is employed for transmission which can result in increased energy consumption, high network delay and poor packet delivery ratio (PDR). In the subsequent IEEE 802.15.4-2015 standard, a Time-slotted Channel Hopping (TSCH) mechanism has been developed which al...

Time sensitive virtual machines that run real-time control tasks are constrained by hard timing requirements. Optimal resource management and guarantee the hard timing requirements of virtual machines are critical goals. Basically, cloud resource usage predicting and resource reservation play a crucial role to achieve these two goals. So, we propos...

The placement of a virtual machine in cloud computing generates a cost derived from consuming the energy of the allocated network elements. In this paper, we present an optimization model for effective virtual machine placement in the heterogeneous multi-cloud systems by considering peak demand time and geographical position of allocated resources,...

Any properly designed network coding technique can result in increased throughput and reliability of multi-hop wireless networks by taking advantage of the broadcast nature of wireless medium. In many inter-flow network coding schemes nodes are encouraged to overhear neighbour’s traffic in order to improve coding opportunities at the transmitter no...

Cognitive radio networks (CRNs) are the solution for the problem of underutilizing the licensed spectrum for which there are more requests in the last couple of decades. In CRNs, Secondary users (SUs) are permitted to access opportunistically the licensed spectrum owned by primary users (PUs). In this paper, we address the problem of joint routing...

In the routing process, the cost (or weight) of routes determine via a function named routing criterion. Therefore, the design of Optimal Routing Criterion (ORC) is one of the most crucial issues in routing. The existence of unstable channels in Cognitive Radio Network (CRN) has caused the design of ORC in CRN converts to a challenging topic. In th...

In recent years, cooperative communications have been widely used to improve the spectrum efficiency in cognitive radio networks. In this paper, we propose a new cooperative model involving primary and secondary users, where a primary transmitter may select a number of the secondary users to act as relays in order to maximize its data rate and to t...

In opportunistic networks, nodes communicate intermittently based on store‐carry‐forward paradigm while exploiting node mobility. The challenge is to determine the ideal nodes to deliver the messages since there is no end‐to‐end connectivity. The nodes might make this decision based on the data sensed from the network. This technique is not ideal i...

Nowadays, web servers have to respond to the huge amount of requests; therefore, balancing the load between server replicas becomes vital and critical. Conventional load balancers have been dedicated hardware that is susceptible being a single point of failure, vendor-dependent and not flexible. In this work, we propose a flexible and programmable...

The instability of operational channels on cognitive radio networks (CRNs), which is due to the stochastic behavior of primary users (PUs), has increased the complexity of the design of the optimal routing criterion (ORC) in CRNs. The exploitation of available opportunities in CRNs, such as the channel diversity, as well as alternative routes provi...

Designing an efficient routing protocol for cognitive radio networks is critical due to the dynamic behavior of the primary users. Based on empirical studies, the primary users activity on the licensed channels has periodicity comprised of several stages, and that the model of primary users activity may change during different stages. This paper ha...

An opportunistic network is a wireless ad hoc network that has frequently intermittent connectivity due to nodes’ mobility. These spare, unpredictable networks aim to solve the prolonged delay paths by a store-carry-forward scheme. It is difficult to determine the appropriate nodes to forward the messages since there are few opportunistic contacts....

In mobile ad hoc networks, clustering refers to the process of identifying the set of clusterheads that optimize one or more network objectives. To optimize each objective, the nodes of the network should be evaluated and compared in terms of one or more corresponding attributes. In many-objective problems, as the number of favorable network object...

Recently, cooperative communications are used to improve the communications performance in cognitive radio networks. In this paper, we present a new model for implicit cooperation between primary users and secondary users (SUs), where SUs transparently relay packets of primary transmitters (PTs) towards their primary receivers encouraging PTs to re...

Barrier coverage is one of the main applications of wireless sensor networks. There are two kinds of barrier coverage: weak and strong. While weak barrier coverage can only guarantee detecting intruders moving along predetermined or congruent paths, strong barrier coverage guarantees detecting all intruders regardless of their crossing paths. In th...

In this paper, we consider adjustable-orientation directional sensor networks (ADODSNs) in which nodes are deployed based on Poisson Point Process and the orientation of sensor nodes is distributed between 0 and 2π independently and uniformly. Despite of other kinds of directional sensor networks, orientation of sensor nodes in ADODSNS could be adj...

In this paper, we present a mathematical framework to evaluate the performance of a typical outdoor user in an urban two-tier mobile network under a biased user association. The urban environment is abstracted by a Boolean scheme of blockages, which affects the deployment of outdoor base stations (BSs) and indoor small cell BSs, as well as the sign...

Offloading mobile users from highly loaded macro base stations (BSs) to lightly-loaded small cell BSs is critical for utilizing the full potential of heterogeneous cellular networks (HCNs). However, to alleviate the signal-to-interference-plus-noise ratio (SINR) degradation of so called biased users, offloading needs to be activated in conjunction...

In mobile ad hoc networks, clustering refers to the process of identifying the set of clusterheads that optimize one or more network objectives. To optimize each objective, the nodes of the network should be evaluated and compared in terms of one or more corresponding attributes. In many-objective problems, as the number of favorable network object...

Recently, computation offloading has become one of the common and efficient ways to minimize the energy expenditure. Considering the aspects of mobile-cloud communication, energy optimization is from the necessities of this offloading. Moreover, the variable and mobile states of mobile devices environments has a significance on this communication....

Network coding is all about combining a variety of packets and forwarding as much packets as possible in each transmission operation. The network coding technique improves the throughput efficiency of multi-hop wireless networks by taking advantage of the broadcast nature of wireless channels. However, there are some scenarios where the coding cann...

This paper proposes a real-time and energy aware routing protocol for industrial wireless sensor networks, called RTEA. Two-hop neighborhood information routing is adopted from THVR routing protocol, however our routing protocol has low control packet overhead and differentiates packets based on their deadlines. The packet deadline is updated in ea...

Mobile phones play an increasingly significant role in everyday lives. They are the most efficient and accessible communication and calculation devices that require no specific time or location. Rapid development of portable calculation created a driving force to develop a simultaneous technology in the markets. However, portable devices are facing...

Mobile phones play an increasingly significant role in everyday lives. They are the most efficient and accessible communication and calculation devices that require no specific time or location. Rapid development of portable calculation created a driving force to develop a simultaneous technology in the markets. However, portable devices are facing...

Mobile phones play an increasingly significant roles in everyday lives. They are the most efficient and accessible communication and calculation devices that require no specific time or location. Rapid development of portable calculation created a driving force to develop a simultaneous technology in the markets. However, portable devices are facin...

Mobile phones play an increasingly significant roles in everyday lives. They are the most efficient and accessible communication and calculation devices that require no specific time or location. Rapid development of portable calculation created a driving force to develop a simultaneous technology in the markets. However, portable devices are facin...

Opportunistic network can help in situations where network connectivity is sparse or with large variations in density, or even when there is no end-to-end connectivity by providing a communication solution for non-real-time applications. Unstable and fluctuate end-to-end path is let to have a significant challenge in routing messages. Uneven nodes'...

Heterogeneous cellular networks have received considerable attention in the literature owing to increased data demands of cellular network users. Recently, Poisson Point processes (PPPs) are vastly used for modeling and analyzing cellular networks because of their accuracy and tractability. However, results in this area suffer from a big drawback....

Routing in Vehicular Ad hoc Networks (VANETs) has found significant attention because of its unique features such as lack of energy constraints and high-speed vehicles applications. Besides, since these networks are highly dynamic, design process of routing algorithms suitable for an urban environment is extremely challenging. Appropriate algorithm...

In mobile ad-hoc networks (MANETs), each node tries to maximise its utility in the network and saves its limited resources including energy and bandwidth due to different ownerships and selfish behaviour, which can cause nodes not to cooperate in network tasks such as topology control and packet forwarding and it affects performance of all tasks of...

Given an initially uncovered field, and as more and more directional sensors (sensors with sector shape sensing area) are continuously added to the sensor network, the size of partial covered areas increases. At some point, the situation abruptly changes from small fragmented covered areas to a single large covered area. This abrupt change is calle...

By rapid advances in the development of electronic components and with declining cost of sensor network deployment, we are witnessing the amazing growth of these networks. The energy consumption constraints have imposed the importance and necessity of new concepts such as data aggregation. In this paper, a new method is proposed for aggregating the...

Opportunistic networks (ON) allow for routing in networks where contemporaneous end-to-end path are unstable. Due to uneven and fluctuant node density, both links and nodes in our uncertain environment may be inherently unreliable and disconnections may be long-lived. A critical challenge for ONs is determining routes through the network without ev...

Along with advances in technologies and equipment of vehicles with communication devices, vehicular networks were developed. Various applications are proposed and defined for these networks, and as the number of deaths caused by accidents are increasing, safety applications became the most important one. Dynamicity of the nodes in addition to wirel...

Network coding is used to improve the throughput of communication networks. In this technique, the intermediate nodes mix packets to increase the information content of each transmission. For each flow, a coding pattern is defined as a set of flows that can be coded together. Finding a suitable coding pattern is a challenge due to much complexity....

Recently, network coding emerged as a promising technology that can provide significant improvements in throughput and energy efficiency of wireless networks. Many implementations of network coding in wireless networks, such as COPE, encourage nodes to overhear to improve the coding opportunities so that they can create better opportunities for cod...

Topology control in MANETs assigns power level to each node while preserving certain global properties such as connectivity and energy efficiency. Selfishness of nodes affects different tasks in such networks. Due to limited energy resources, nodes may reduce their power level selfishly. Also, nodes can be selfish in packet forwarding and they may...

Today we are witnessing an amazing growth of wireless sensor networks due to many factors including but limited to reducing cost of semiconductor components, rapid deployment of wireless networks, and attention to low-power aspect that makes these networks suitable for energy sensitive applications to a large extent. The power consumption requireme...

In Wireless Sensor Networks (WSNs), power consumption of sensor nodes is the main constraint. Emerging in-network aggregation techniques are increasingly being sought after to address this key challenge and to save precious energy. One application of WSNs is in data gathering of moving objects. In order to achieve complete coverage, this type of ap...

Without any doubt, IP Address lookup is an important function of routers. As size of routing tables getting larger and links getting faster, the need of a fast and efficient method to Lookup prefix addresses get more sensed. Although there was a period that hardware based approaches almost faded the software ones; but recently by introducing the mu...

Wireless Sensor Networks WSNs consist of inexpensive low-power miniature sensing devices with severe power constraints, necessitating energy-efficient solutions for networking operations. Major prior art proposals have been primarily directed towards minimising the communication cost, either implicitly assuming away the computation overhead as bein...

Wide spread use of wireless sensor networks (WSNs) in critical applications shows the importance of Quality of service (QoS) in these networks. Timeliness is one of the QoS parameters which has great importance in real time applications such as earthquake detection. Several geographic routing protocols have been proposed for WSNs which provide QoS...

Nowadays, monitoring of vast environments and gathering their information by wireless sensor networks has become popular. A challenging issue of these networks is storage and retrieval of events and detected data by the network nodes. The problem uprises when the sensor network has an irregular and complex shape and includes some holes with no node...

In-Network storage model is effective to reduce communications overhead in the wireless sensor networks because it stores the sensed data in the sensors inside the network instead of sending them to the sink node. When the sink node wants to get some stored data it can restore it by sending request to the sensors that has stored the required data....

Energy conservation and interference reduction are the two important goals of any topology control algorithm in wireless multi-hop sensor networks, but impacts of traffic on interference have been largely ignored in mostly all previous works on topology control. Inspired by this challenge, we set out to investigate the impact of traffic load on nod...

In this paper, we investigated the problem of finding an efficient topology for delay-constrained data in WSNs. As we know topology control is one of the important mechanisms designed for decreasing energy consumption in WSNs. Since topology control may increase the end-to-end delay, one of the criteria's should be considered in topology control al...

In Wireless Sensor Networks (WSNs) due to unfavorable environmental conditions that sensor nodes are placed into and some other reasons, power limitation of sensor nodes is the main challenge. Emerging in-network aggregation techniques are increasingly being sought to overcome this limitation and to save energy. Data aggregation methods can be faci...

We investigate the problem of finding an efficient topology for delay-constrained data in WSNs. Since topology control may increase the end-to-end delay, one of the criterion's that should be considered in topology control algorithms is restricting delay. Existing works utilized hop count measure for delay; yet hop count is not a suitable criterion...

Energy conservation and interference reduction are the two main goals of any topology control algorithm in wireless multi-hop networks, but impacts of traffic on interference have been largely ignored in almost all previous works. In this paper, we showed that traffic load has significant influence on energy consumption of network nodes and then we...

In Wireless Sensor Networks (WSNs), sensor nodes power consumption is the main challenge. Emerging in-network aggregation techniques are increasingly being sought to overcome this constraint and to save precious energy. WSN applications require spatially dense deployment of sensor nodes to achieve full coverage. As a result, sensors observations ha...

In wireless sensor networks design, nodes are dispersed in the environment with high density. Therefore, topology control is one of the mechanisms designers employ to monitor and reduce power consumption in these networks. Since topology control may increase the end-to-end delay, one of the factors that should be considered in topology control algo...

With recent advances, the trend has shifted from battery-powered wireless sensor networks towards ones powered by ambient energy harvesters (WSN-HEAP). In such networks, operability of the node is dependent on the harvesting rate which is usually stochastic in nature. Therefore, it is necessary to devise routing protocols with energy management cap...

In Wireless Sensor Networks (WSNs), sensor nodes power consumption is main challenge. Emerging in-network aggregation techniques are increasingly being sought to overcome this constraint and to save precious energy. In our previously proposed method, entitled “Data Aggregation for Mobile Object Using Rate-Distortion” (DAMORD), we introduced a mathe...

Traffic signal controllers and route guidance systems are two major subsystems of Intelligent Transportation Systems that influence each other directly. Due to correlation between these subsystems, some research has been done to combine them into an integrated system. In this paper, PersianGulf - an autonomous combined traffic signal controller and...

Rate adaptation algorithms play an important role in improving the performance of WLANs. However, just few numbers of efforts have been made on this area. These algorithms try to provide more throughputs by increasing or decreasing rates upon channel condition and obtained good put However, it is a little different in 802.11n. Unfortunately, just a...

In wireless sensor networks sampling time interval and the number of nodes involved in each stage of tracking are important factors which have high effect on the efficiency of target tracking applications. In this paper a new target tracking method has been proposed which at each time step employs two helpful tools. First, an extended Kalman filter...

The time-constrained shortest path problem is an important generalization of the shortest path problem. The basic feature in time-constrained shortest path problem is considering when a node in the network can be visited under some time constraints. In this paper, a label-setting shortest path algorithm will be proposed to use in the synchronized t...

In wireless ad hoc networks cooperation among nodes cannot always be assumed since nodes with limited resources and different owners are capable of making independent decisions. Cooperation problems in topology control and packet forwarding tasks have been mostly studied separately but these two tasks are not independent. Considering a joint cooper...

The effective use of vast amounts of collected data in the wireless sensor network requires scalable and energy- efficient algorithms. A provided solution is the data-centric storage which itself suffers from the hot-spot problem. This problem occurs when the mass of sent queries and events to a particular node is more than the capacity of that nod...

Recently mobile widespread services are widely deployed. The delivery of these services should be secured. In widespread mobile environment, various security threats are posed to the user, network and service/content providers, so security requirements are needed to be identified to reduce these threats. In this paper these threats, their possible...

Energy efficiency should be considered as a key design objective in wireless sensor networks (WSNs), since a sensor node can only be equipped with a limited energy supply. Clustering is one of the well-known design methods for managing the energy consumption in WSNs. Rotating role of cluster heads (CH) among nodes in these networks is an important...

In wireless sensor networks, sensor nodes are capable of not only measuring real world phenomena, but also storing, processing, and transferring these measurements. Many techniques have been proposed for storing and retrieving data in these networks. These methods are classified into three main categories. Data-centric storage is the most important...

Location-based routing intends to send packets toward geographic direction of destination. For this, source nodes needs to known about destination position via a location service. Whereas the main concept of ad hoc networking is being independent from an infrastructure, applying a distribution algorithm has been a key design principle for a locatio...

Wireless sensor networks consist of nodes with severe energy constraints and thus, they must use energy saving algorithms in different layers. Despite the prior work, the computational cost in a wireless sensor network is usually neglected compared to the communication cost; it may not admit to in which large volumes of data packets are being trans...

Today IPSec virtual private networks are widely used to establish secure network connections between a pair of hosts, between a pair of security gateways, or between a security gateway and a host. The complexity and variety of rules in an IPSec policy may result in a combination of rules which not only do not provide the required security services,...

The computational cost in a wireless sensor network is usually considered neglected in comparison to the communication cost. While this assumption is considered true, it may fail if data volumes are significantly large. In such situations, it is more rational to consider the computational cost as well as the communication cost for energy related de...

Position based routing protocols are kinds of routing protocols, which use nodes location information, instead of links information to routing. In position based routing protocols, it supposed that the packet source node has position information of itself and it's neighbors and the packet destination node. Greedy is a very important position based...

In wireless AdHoc networks, all its nodes behave as routers and take part in its discovery and maintenance of routs to other nodes. Therefore, the cooperation of nodes is very important. With presence of selfish or malicious nodes the performance of the network may greatly degrade. In order to enforce the cooperation between the nodes in the system...

In wireless sensor networks (WSNs), data aggregation schemes have been extensively investigated in order to reduce energy, although it has a great side-effect, the end to end delay is increased. This paper proposes a layered clustering structure for data aggregation in wireless sensor networks. In this proposed structure, each layer of clusters has...

Flooding algorithm is one of the most important fundamental operations for routing protocols in mobile ad hoc networks. Since flooding algorithm generates many redundant messages, it is usually very costly that leads to consume scarce resources such as bandwidth and battery powers in mobile ad hoc networks. It also causes a problem known as the bro...

One of the most important protocols for implementing tunnels in order to take action of secure virtual private network is IPsec protocol. IPsec policies are used widely in order to limit access to information in security gateways or firewalls. The security treatment, namely (Deny, Allow or Encrypt) is done for outbound as well as inbound traffic by...

Vehicular ad hoc networks based on IEEE 802.11(WLAN) technology are emerging technologies for future Intelligent Transportation Systems (ITS). We investigate the behavior of routing protocols in vehicular networks by using microscopic mobility information based on the real road maps. The simulation results show the remarkable effect of the real mob...

In this paper, we apply infinitesimal perturbation analysis (IPA) to packet loss and buffer workload-related performance metrics in tandem networks of two-class stochastic fluid models (SFM). We consider these performance metrics at a downstream SFM node as a function of the controlled traffic stream's threshold parameter at an upstream SFM node. T...

In this paper, we apply infinitesimal perturbation analysis (IPA) to packet loss and buffer workload-related performance metrics in tandem networks of two-class stochastic fluid models (SFM). We consider these performance metrics at a downstream SFM node as a function of the controlled traffic stream’s threshold parameter at an upstream SFM node. T...

In mobile ad hoc networks, communication between distant nodes relies on cooperation of intermediate nodes to forward packets to the destination. But, a selfish node for saving its resources (e.g. battery power and bandwidth) does not cooperate and drops packets which are not belonging to it. If there is no mechanism to cope with selfish nodes, coo...

The objective of this study is to propose a new bufferless optical packet switching architecture in which thew converters, needed to solve output packet contentions, are used in two levels. The architecture is equipped with limited-range wavelength converters (LRWCs) at the first level and with shared and full-range wavelength converters (FRWCs) at...

IP address lookup is one of the most challenging problems of Internet routers. In this paper, an IP lookup rate of 263 Mlps (Million lookups per second) is achieved using a novel architecture on reconfigurable hardware platform. A partial reconfiguration may be needed for a small fraction of route updates. Prefixes can be added or removed at a rate...

In this paper, we apply infinitesimal perturbation analysis (IPA) to packet loss and buffer workload related performance metrics in tandem networks of two-class stochastic fluid models (SFM). We consider these performance metrics at a downstream SFM node as a function of the controlled traffic stream's threshold parameter at an upstream SFM node. T...

Traffic engineering is aimed at optimizing the utilization of existing network resources for load balance and failure recovery. Multiprotocol label switching (MPLS), constraint-based routing, enhanced link state Internet gateway protocol (IGP), and path signaling protocols are useful tools for traffic engineering. We discuss the general issues of d...

In this paper, we introduce homogeneous cosimulation method, which is suitable for modeling and simulation of systems comprising hardware (HW) and software (SW) components. In this method, a hardware description language with embedded programming capabilities (like VHDL) is used to model both HW/SW parts at any desired level of abstraction. Because...

Today's high-speed telecommunications networks are growing ever more complicated. In this environment, there is a need for fast restoration strategies to recover from multiple network failures. We propose a new scheme that provides multiple reliability levels for different service classes. This scheme proposes the addition of a new parameter define...

Moments and functions of moments have been utilized as pattern features in various applications to achieve invariant recognition of two-dimensional image patterns. This paper introduces an experimental evaluation of the effectiveness of utilizing orthogonal moments such as Zernike moments, pseudo Zernike moments, and Legendre moments in recognition...

This paper proposed a new self-healing scheme that provides multiple reliability levels for different service classes. In this scheme each restoration priority determines the priority of restoration of each service class. In the proposed scheme the the traffic flow of a failed working VP may be restore by one or more than one backup VP. Computer si...

Many wireless sensor network applications must resolve the inherent conflict between energy efficient communication and the need to achieve desired quality of service such as end-to-end communication delay. To address this challenge, we propose a new protocol which tries to resolve the finding a trade off between lifetime of the network and real-ti...