Abdelouahid Derhab

Data replication protocols for mobile ad-hoc networks: a survey and taxonomy

In mobile ad-hoc networks, frequent network partitioning and the failure of mobile nodes due to exhaustion of their battery power can considerably decrease data availability. In addition, the increase in network size and node mobility cause the performance of data access to degrade. To deal with these issues, a number of data replication protocols have been proposed in the recent years. This paper surveys the existing data replication protocols in mobile ad-hoc networks and proposes a classification scheme that categorizes the protocols into various classes, with respect to the issues they address. Network partitioning, energy consumption, and scalability are the three issues that are identified in this paper, and which have not been previously considered in the fixed networks. The paper also provides a comparison of the protocols and investigates opportunities for future research.

A Self-Stabilizing Leader Election Algorithm in Highly Dynamic Ad Hoc Mobile Networks

The classical definition of a self-stabilizing algorithm assumes generally that there are no faults in the system long enough for the algorithm to stabilize. Such an assumption cannot be applied to ad hoc mobile networks characterized by their highly dynamic topology. In this paper, we propose a self-stabilizing leader election algorithm that can tolerate multiple concurrent topological changes. By introducing the time-interval-based computation concept, the algorithm ensures that a network partition can within a finite time converge to a legitimate state even if topological changes occur during the convergence time. Our simulation results show that our algorithm can ensure that each node has a leader over 99 percent of the time. We also give an upper bound on the frequency at which network components merge to guarantee the convergence.

Data Aggregation Scheduling Algorithms in Wireless Sensor Networks: Solutions and Challenges

Energy limitation is the main concern of any wireless sensor network application. The communication between nodes is the greedy factor for the energy consumption. One important mechanism to reduce energy consumption is the in-network data aggregation. In-network data aggregation removes redundancy as well as unnecessary data forwarding, and hence cuts on the energy used in communications. Recently a new kind of applications are proposed which consider, in addition to energy efficiency, data latency and accuracy as important factors. Reducing data latency helps increasing the network throughput and early events detection. Before performing the aggregation process, each node should wait for a predefined time called WT (waiting time) to receive data from other nodes. Data latency (resp., accuracy) is decreased (resp., increased), if network nodes are well scheduled through optimal distribution of WT over the nodes. Many solutions have been proposed to schedule network nodes in order to make the data aggregation process more efficient. In this paper, we propose a taxonomy and classification of existing data aggregation scheduling solutions. We survey main solutions in the literature and illustrate their operations through examples. Furthermore, we discuss each solution and analyze it against performance criteria such as data latency and accuracy, energy consumption and collision avoidance. Finally, we shed some light on future research directions and open issues after deep analysis of existing solutions.

Human-oriented design of secure Machine-to-Machine communication system for e-Healthcare society

Propose and implement a M2M Secure communication for e-Healthcare society.Perform tasks autonomously to minimize the workload and stress of medical staff.Different actors in the e-Healthcare society can interact in a secure manner.Staff dynamic assignments with intelligent authentication to ensure data privacy.Patients to share their health information while preserving privacy issue. In this paper, we propose a Machine to Machine (M2M) Low Cost and Secure (LCS) communication system for e-Healthcare society. The system is designed to take into consideration the psychological issues related to all actors in the e-Healthcare society such as: stress due to high workload, anxiety, and loneliness. The system is capable of performing most of the tasks in an autonomous and intelligent manner, which minimizes the workload of medical staffs, and consequently minimizes the associated psychological stress and improves the quality of patient care as well as the system performance. We show how the different actors in the e-Healthcare society can interact with each other in a secure manner. To ensure data privacy, the mechanism involves intelligent authentication based on random distributive key management, electronic certificate distribution, and modified realm Kerberos. The system handles dynamic assignments of doctors to specific patients. It also addresses the need for patients to share their health information with strangers while dealing with the privacy preservation issue. Finally, the simulation type implementation is performed on Visual Basic .net 2013 that shows the success of the proposed Low Cost and Secure (LCS) algorithm.

Semi-structured and unstructured data aggregation scheduling in wireless sensor networks

This paper focuses on data aggregation scheduling problem in wireless sensor networks (WSNs), to minimize time latency. Prior works on this problem have adopted a structured approach, in which a tree-based structure is used as an input for the scheduling algorithm. As the scheduling performance mainly depends on the supplied aggregation tree, such an approach cannot guarantee optimal performance. To address this problem, we propose approaches based on Semi-structured Topology (DAS-ST) and Unstructured Topology (DAS-UT). The approaches are based on two key design features, which are: (1) simultaneous execution of aggregation tree construction and scheduling, and (2) parent selection criteria that maximize the choices of parents for each node and maximize time slot reuse. We prove that the latency of DAS-ST is upper-bounded by ([2π/arccos(1/1+ϵ)]+4)R+Δ-4, where R is the network radius, Δ is the maximum node degree, and 0.05 <; ϵ ≤ 1. Simulations results show that DAS-UT outperforms DAS-ST and four competitive state-of-the-art aggregation scheduling algorithms in terms of latency and network lifetime.

A pull‐based service replication protocol in mobile ad hoc networks

The mobility of nodes in ad hoc networks can lead to frequent network partitioning. This partitioning disconnects many nodes from a centralised server. Being aware of a future partitioning can help to provide a continuous service availability for all mobile nodes. In this paper, we propose a service replication protocol consisting of three distributed algorithms. This protocol (i) predicts the occurrence of network partitioning, which allows to create service replicas in the future separate partitions and (ii) constructs a dynamic service replicas deployment scheme. Using linear-time temporal logic, we show that each detection of network partitioning can be predicted before its occurrence. Our simulation results show that the proposed protocol guarantees service availability to all mobile nodes without incurring high cost. Copyright

A partition prediction algorithm for service replication in mobile ad hoc networks

Due to the mobility of nodes in ad hoc networks, network topology is dynamic and unpredictable, which leads to frequent network partitioning. This partitioning disconnects many nodes from the centralized server. Being aware of future partitioning can help to provide a continuous service availability for all mobile nodes. In this paper, we propose a partition prediction algorithm, based on: (i) the partition detection mechanism used by TORA routing protocol and (ii) the residual link lifetime of wireless links. The node that predicts network partitioning, demands the server node to replicate the service in the future separate partition before its disconnection. We propose also a scheme that describes how the service replicas are dynamically deployed in the network. Using linear time temporal logic, we show that whenever a partition is detected, then it has been predicted before. Our analysis of complexity shows that the proposed algorithm guarantee the service availability to each mobile node without incurring high cost.

Distributed Low-Latency Data Aggregation Scheduling in Wireless Sensor Networks

This article considers the data aggregation scheduling problem, where a collision-free schedule is determined in a distributed way to route the aggregated data from all the sensor nodes to the base station within the least time duration. The algorithm proposed in this article (Distributed algorithm for Integrated tree Construction and data Aggregation (DICA)) intertwines the tree formation and node scheduling to reduce the time latency. Furthermore, while forming the aggregation tree, DICA maximizes the available choices for parent selection at every node, where a parent may have the same, lower, or higher hop count to the base station. The correctness of the DICA is formally proven, and upper bounds for time and communication overhead are derived. Its performance is evaluated through simulation and compared with six delay-aware aggregation algorithms. The results show that DICA outperforms competing schemes. The article also presents a general hardware-in-the-loop framework (DAF) for validating data aggregation schemes on Wireless Sensor Networks (WSNs). The framework factors in practical issues such as clock synchronization and the sensor node hardware. DICA is implemented and validated using this framework on a test bed of sensor motes that runs TinyOS 2.x, and it is compared with a distributed protocol (DAS) that is also implemented using the proposed framework.

On resilience of Wireless Mesh routing protocol against DoS attacks in IoT-based ambient assisted living applications

The future of ambient assisted living (AAL) especially eHealthcare almost depends on the smart objects that are part of the Internet of things (IoT). In our AAL scenario, these objects collect and transfer real-time information about the patients to the hospital server with the help of Wireless Mesh Network (WMN). Due to the multi-hop nature of mesh networks, it is possible for an adversary to reroute the network traffic via many denial of service (DoS) attacks, and hence affect the correct functionality of the mesh routing protocol. In this paper, based on a comparative study, we choose the most suitable secure mesh routing protocol for IoT-based AAL applications. Then, we analyze the resilience of this protocol against DoS attacks. Focusing on the hello flooding attack, the protocol is simulated and analyzed in terms of data packet delivery ratio, delay, and throughput. Simulation results show that the chosen protocol is totally resilient against DoS attack and can be one of the best candidates for secure routing in IoT-based AAL applications.

Low delay and secure M2M communication mechanism for eHealthcare

Currently, the eHealthcare information management is the most critical and hot research topic. Especially with the involvement of new and promising telecommunication technologies like Machine to Machine (M2M) Communication. In M2M communication the devices interact and exchange information with each other in an autonomous manner to accomplish the required tasks. Mostly machine communicate to another machine wirelessly. The wireless communication opens the medium for enormous vulnerabilities and make it very easy for hackers to access the confidential information and can perform malicious activities. In this paper, we propose a Machine to Machine (M2M) Low Delay and Secure (LDS) communication system for e-healthcare community based on random distributive key management scheme and modified Kerberos realm to ensure data security. The system is capable to perform the tasks in an autonomous and intelligent manner that minimizes the workload of medical staffs, and improves the quality of patient care as well as the system performance. We show how the different actors in the e-healthcare community can interact with each other in a secure manner. The system handles dynamic assignments of doctors to specific patients. The proposed architecture further provides security against false attack, false triggering and temper attack. Finally, the simulation type implementation is performed on Visual Basic .net 2013 that shows the feasibility of the proposed Low Delay and Secure (LDS) algorithm.