CERIST DL :: Browsing by Author "Bagaa, Miloud"

Browsing by Author "Bagaa, Miloud"

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A Variant of Connected Dominating Set for Application in Communication Networks
(CERIST, 2015-03-30) Djenouri, Djamel; Bagaa, Miloud
This paper considers a variant of the connected dominating set (CDS) problem in a graph G = (V;E). The considered problem consists in minimizing the number of CDS vertices that belong to a subset V ′ in V . As far as we know, this problem has not been treated in the literature. Nevertheless, its resolution would be useful in many communication network applications, such as the selection of relay nodes in heterogenous wireless ad hoc networks where only a subset of powerful nodes (e.g., energy or memory rich nodes) may form the network backbone act as relays, or where it is preferable to select relays from these nodes and minimize the number of non-powerful nodes that act as relays. Replacement of non-powerful nodes might be necessary either at the initialization (after deployment), or during the network lifetime, which justifies the need to minimize their number. The problem is first modeled and reduced to the minimum weighted connected dominating set (WCDS) problem in a vertex weighted graph, and then it is resolved by taking advantage of the simple form of the weight function using integer linear programming (ILP). A heuristic is also proposed for large scale resolution. Simulation results confirms closeness of the proposed heuristic to the optimal solution obtained by the ILP, and scalability of the heuristic.
CCS_WHMS: A Congestion Control Scheme for Wearable Health Management System
(Springer Link, 2015-10-21) Kafi, Mohamed Amine; Ben Othman, Jalel; Bagaa, Miloud; Badache, Nadjib
Wearable computing is becoming a more and more attracting field in the last years thanks to the miniaturisation of electronic devices. Wearable healthcare monitoring systems (WHMS) as an important client of wearable computing technology has gained a lot. Indeed, the wearable sensors and their surrounding healthcare applications bring a lot of benefits to patients, elderly people and medical staff, so facilitating their daily life quality. But from a research point of view, there is still work to accomplish in order to overcome the gap between hardware and software parts. In this paper, we target the problem of congestion control when all these healthcare sensed data have to reach the destination in a reliable manner that avoids repetitive transmission which wastes precious energy or leads to loss of important information in emergency cases, too. We propose a congestion control scheme CCS_WHMS that ensures efficient and fair data delivery while used in the body wearable system part or in the multi-hop inter bodies wearable ones to get the destination. As the congestion detection paradigm is very important in the control process, we do experimental tests to compare between state of the art congestion detection methods, using MICAz motes, in order to choose the appropriate one for our scheme.
CCS_WHMS: A Congestion Control Scheme for Wearable Health Management System
(Springer US, 2015-12) Kafi, Mohamed Amine; Ben Othman, Jalel; Bagaa, Miloud; Badache, Nadjib
Wearable computing is becoming a more and more attracting field in the last years thanks to the miniaturisation of electronic devices. Wearable healthcare monitoring systems (WHMS) as an important client of wearable computing technology has gained a lot. Indeed, the wearable sensors and their surrounding healthcare applications bring a lot of benefits to patients, elderly people and medical staff, so facilitating their daily life quality. But from a research point of view, there is still work to accomplish in order to overcome the gap between hardware and software parts. In this paper, we target the problem of congestion control when all these healthcare sensed data have to reach the destination in a reliable manner that avoids repetitive transmission which wastes precious energy or leads to loss of important information in emergency cases, too. We propose a congestion control scheme CCS_WHMS that ensures efficient and fair data delivery while used in the body wearable system part or in the multi-hop inter bodies wearable ones to get the destination. As the congestion detection paradigm is very important in the control process, we do experimental tests to compare between state of the art congestion detection methods, using MICAz motes, in order to choose the appropriate one for our scheme.
Distributed Low-Latency Data Aggregation Scheduling in Wireless Sensor Networks
(ACM, 2015-04) Bagaa, Miloud; Younis, Mohamed; Djenouri, Djamel; Derhab, Abdelouahid; Badache, Nadjib
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.
DPFTT: Distributed Particle Filter for Target Tracking in the Internet of Things
(IEEE, 2023-11-07) Boulkaboul, Sahar; Djenouri, Djamel; Bagaa, Miloud
A novel distributed particle filter algorithm for target tracking is proposed in this paper. It uses new metrics and addresses the measurement uncertainty problem by adapting the particle filter to environmental changes and estimating the kinematic (motion-related) parameters of the target. The aim is to calculate the distance between the Gaussian-distributed probability densities of kinematic data and to generate the optimal distribution that maximizes the precision. The proposed data fusion method can be used in several smart environments and Internet of Things (IoT) applications that call for target tracking, such as smart building applications, security surveillance, smart healthcare, and intelligent transportation, to mention a few. The diverse estimation techniques were compared with the state-of-the-art solutions by measuring the estimation root mean square error in different settings under different conditions, including high-noise environments. The simulation results show that the proposed algorithm is scalable and outperforms the standard particle filter, the improved particle filter based on KLD, and the consensus-based particle filter algorithm.
DZ50: Energy-Efficient Wireless Sensor Mote Platform for Low Data Rate Applications
(CERIST, 2014-07-07) Ouadjaout, Abdelraouf; Lasla, Noureddine; Bagaa, Miloud; Doudou, Messaoud; Zizoua, Cherif; Kafi, Mohamed Amine; Derhab, Abdelouahid; Djenouri, Djamel; Badache, Nadjib
A low cost and energy efficient wireless sensor mote platform for low data rate monitoring applications is presented. The new platform, named DZ50, is based on the ATmega328P micro-controller and the RFM12b transceiver, which consume very low energy in low-power mode. Considerable energy saving can be achieved by reducing the power consumption during inactive (sleep) mode, notably in low data rate applications featured by long inactive periods. Without loss of generality, spot monitoring in a Smart Parking System (SPS) and soil moisture in a Precision Irrigation System (PIS) are selected as typical representative of low data rate applications. The performance of the new platform is investigated for typical scenarios of the selected applications and compared with that of MicaZ and TelosB. Energy measurement has been carried out for different network operation states and settings, where the results reveal that the proposed platform allows to multiply the battery lifetime up to 7 times compared to MicaZ and TelosB motes in 10s sampling period scenarios.
DZ50: Energy-efficient Wireless Sensor Mote Platform for Low Data Rate Applications
(Elsevier, 2014) Ouadjaout, Abdelraouf; Lasla, Noureddine; Bagaa, Miloud; Doudou, Messaoud; Zizoua, Cherif; Kafi, Mohamed Amine; Derhab, Abdelouahid; Djenouri, Djamel; Badache, Nadjib
A low cost and energy e_cient wireless sensor mote platform for low data rate monitoring applications is presented. The new platform, named DZ50, is based on the ATmega328P micro-controller and the RFM12b transceiver, which consume very low energy in low-power mode. Considerable energy saving can be achieved by reducing the power consumption during inactive (sleep) mode, notably in low data rate applications featured by long inactive periods. Without loss of generality, spot monitoring in a Smart Parking System (SPS) and soil moisture in a Precision Irrigation System (PIS) are selected as typical representative of low data rate applications. The performance of the new platform is investigated for typical scenarios of the selected applications and compared with that of MicaZ and TelosB. Energy measurements have been carried out for di_erent network operation states and settings, where the results reveal that the proposed platform allows to multiply the battery lifetime up to 7 times compared to MicaZ and TelosB motes in 10s sampling period scenarios.
Efficient data aggregation scheduling in wireless sensor networks with multi-channel links
(ACM, 2013) Bagaa, Miloud; Younis, Mohamed; Badache, Nadjib
In-network data aggregation is often pursued to remove redundancy and correlate the data en-route to the base-station in order to save energy in wireless sensor networks (WSNs). In this paper, we present a novel cross-layer approach for reducing the latency in disseminating aggregated data to the base-station over multi-frequency radio links. Our approach forms the aggregation tree with the objective of increasing the simultaneity of transmissions and reducing buffering delay. Aggregation nodes are picked and time-slots are allocated to the individual sensors so that the most number of ready nodes can transmit their data without delay. Colliding transmissions are avoided by the use of different radio channels. Our approach is validated through simulation and is shown to outperform previously published schemes.
Efficient data aggregation with in-network integrity control for WSN
(Elsevier, 2012-10) Bagaa, Miloud; Challal, Yacine; Ouadjaout, Abdelraouf; Lasla, Noureddine; Badache, Nadjib
Energy is a scarce resource in Wireless Sensor Networks (WSN). Some studies show that more than 70% of energy is consumed in data transmission in WSN. Since most of the time, the sensed information is redundant due to geographically collocated sensors, most of this energy can be saved through data aggregation. Furthermore, data aggregation improves bandwidth usage and reduces collisions due to interference. Unfortunately, while aggregation eliminates redundancy, it makes data integrity verification more complicated since the received data is unique. In this paper, we present a new protocol that provides control integrity for aggregation in wireless sensor networks. Our protocol is based on a two-hop verification mechanism of data integrity. Our solution is essentially different from existing solutions in that it does not require referring to the base station for verifying and detecting faulty aggregated readings, thus providing a totally distributed scheme to guarantee data integrity. We carried out numerical analysis and simulations using the TinyOS environment. Results show that the proposed protocol yields significant savings in energy consumption while preserving data integrity, and outperforms comparable solutions with respect to some important performance criteria.
Efficient Multi-Path Data Aggregation Scheduling in Wireless Sensor Networks
(CERIST, 2013) Bagaa, Miloud; Badache, Nadjib; Ouadjaout, Abdelraouf; Younis, Mohamed
In wireless sensor networks, in-network data aggregation filters out redundant sensor readings in order to reduce the energy and bandwidth consumed in disseminating the data to the base-station. In this paper, we investigate the problem of reliable collection of aggregated data with minimal latency. The aim is to form an aggregation tree such that there are k disjoint paths from each node to the basestation and find a collision-free schedule for node transmissions so that the aggregated data reaches the base-station in minimal time. We propose a novel algorithm for Reliable and Timely dissemination of Aggregated Data (RTAD). RTAD intertwines the formation of the aggregation tree and the allocation of time slots to nodes, and assigns parents to the individual nodes in order to maximize time slot reuse. The simulation results show that RTAD outperforms competing algorithms in the literature.
Energy Harvesting Aware Minimum Spanning Tree for Survivable WSN with Minimum Relay Node Addition
(CERIST, 2016-08-31) Djenouri, Djamel; Bagaa, Miloud; Ali, Chelli; Balasingham, Ilangko
Survivable wireless sensor networks that take advantage of green energy resources from the environment is considered in this paper. The particular problem of constrained relay nodes (RNs) placement to ensure communication coverage in the single-tiered topology while taking advantage of the energy harvesting potentials of sensor nodes (SNs) is dealt with. The contribution is to consider a realistic energy harvesting model where harvesting potentials may vary from one node to another. Without loss of generality, the energy model used in this paper is appropriate to wireless charging, but the proposed solution can be extended to the use of any energy harvesting technology. Based on this model, we propose a heuristic based on spanning tree calculation in an edge weighted graph model where the traffic routed at every node is proportional to its effective energy. RNs are added to help non-leaf nodes in the tree that cannot meet the defined survivability condition. A lower-bound of the proposed model is derived using integer linear programming. The proposed solution is compared by simulation to the single solution from the literature that treats the problem of RNs placement while considering energy harvesting capacity of SNs. A simplified model is used in the simulation to allow comparison. The performance results show that the proposed solution ensures survivability by adding a lower number of RNs.
Energy Harvesting Aware Relay Node Addition for Power-Efficient Coverage in Wireless Sensor Networks
(CERIST, 2015-01-11) Djenouri, Djamel; Bagaa, Miloud
This paper deals with power-efficient coverage in wireless sensor networks (WSN) by taking advantage of energyharvesting capabilities. A general scenario is considered for deployed networks with two types of sensor nodes, harvesting enabled nodes (HNs), and none-harvesting nodes (NHNs). The aim is to use only the HNs for relaying packets, while NHNs use will be limited to sensing and transmitting their own readings. The problem is modeled using graph theory and reduced to finding the minimum weighted connected dominating set in a vertex weighted graph. A limited number of relay nodes is added at the positions close to the NHNs in the resulted set. The weight function ensures minimizing the number of NHNs in the set, and thus reducing the relay nodes to be added. Our contribution is to consider relay node placement (addition) in energy harvesting WSN, where only HNs are used to forward packets. This is to preserve the limited energy of NHNs. Extensive simulation results show that the proposed relay node addition strategy prolongs the network lifetime, from the double, to factors of several tens of times. This is at a reasonable cost in terms of the number of relay nodes added, which is compared to a lower-bound derived in the paper.
Energy-Aware Constrained Relay Node Deployment for Sustainable Wireless Sensor Networks
(IEEE, 2017-03) Djenouri, Djamel; Bagaa, Miloud
This paper considers the problem of communication coverage for sustainable data forwarding in wireless sensor networks, where an energy-aware deployment model of relay nodes (RNs) is proposed. The model used in this paper considers constrained placement and is different from the existing one-tiered and two-tiered models. It supposes two different types of sensor nodes to be deployed, i) energy rich nodes (ERNs), and ii) energy limited nodes (ELNs). The aim is thus to use only the ERNs for relaying packets, while ELN’s use will be limited to sensing and transmitting their own readings. A minimum number of RNs is added if necessary to help ELNs. This intuitively ensures sustainable coverage and prolongs the network lifetime. The problem is reduced to the traditional problem of minimum weighted connected dominating set (MWCDS) in a vertex weighted graph. It is then solved by taking advantage of the simple form of the weight function, both when deriving exact and approximate solutions. Optimal solution is derived using integer linear programming (ILP), and a heuristic is given for the approximate solution. Upper bounds for the approximation of the heuristic (versus the optimal solution) and for its runtime are formally derived. The proposed model and solutions are also evaluated by simulation. The proposed model is compared with the one-tiered and two-tiered models when using similar solution to determine RNs positions, i.e., minimum connected dominating set (MCDS) calculation. Results demonstrate the proposed model considerably improves the network life time compared to the one-tiered model, and this by adding a lower number of RNs compared to the two-tiered model. Further, both the heuristic and the ILP for the MWCDS are evaluated and compared with a state-of-the-art algorithm. The results show the proposed heuristic has runtime close to the ILP while clearly reducing the runtime compared to both ILP and existing heuristics. The results also demonstrate scalability of the proposed solution.
Half-Symmetric Lens based localization algorithm for wireless sensor networks
(IEEE, 2012-10-25) Lasla, Noureddine; Derhab, Abdelouahid; Ouadjaout, Abdelraouf; Bagaa, Miloud; Ksentini, Adlen; Badache, Nadjib
The area-based localization algorithms use only the location information of some reference nodes, called anchors, to give the residence area of the remaining nodes. The current algorithms use triangle, ring or circle as a geometric shape to determine the sensors' residence area. Existing works suffer from two major problems: (1) in some cases, they might issue wrong decisions about nodes' presence inside a given area, or (2) they require high anchor density to achieve a low location estimation error. In this paper, we deal with the localization problem by introducing a new way to determine the sensors' residence area which shows a better accuracy than the existing algorithms. Our new localization algorithm, called HSL (Half Symmetric Lens based localization algorithm for WSN), is based on the geometric shape of half-symmetric lens. We also uses the Voronoi diagram in HSL to mitigate the problem of unlocalizable sensor nodes. Finally, we conduct extensive simulations to evaluate the performance of HSL. Simulation results show that HSL has better locatable ratio and location accuracy compared to representative state-of-the-art area-based algorithms.
Implementation of High Precision Synchronization Protocols in Wireless Sensor Networks
(IEEE, 2014-05) Djenouri, Djamel; Bagaa, Miloud
Microsecond-level time synchronization is needed in realtime applications of wireless sensor networks. While several synchronization protocols have been proposed, most performance evaluations have been limited to theoretical analysis and simulation, with a high level of abstraction by ignoring several practical aspects, e.g. packet handling jitters, clock drifting, packet loss, etc. Effective implementation in real motes faces several challenges due to motes’ limitations and the unreliable lossy channels. These issues affect the protocol performance and precision. Authors of some pragmatic solutions followed empirical approaches for the evaluation, where the proposed solutions have been implemented on real motes and evaluated in testbed experiments. This article throws light on issues related to the implementation of synchronization protocols in WSN. The challenges related to WSN environment are presented, the importance of real implementation and the testbed evaluation are motivated by some experiments that we conducted. Finally, some relevant implementations of the literature that meet microsecondlevel precision are discussed.
Implementation of High Precision Synchronization Protocols in Wireless Sensor Networks
(CERIST, 2014-03-17) Djenouri, Djamel; Bagaa, Miloud
Microsecond-level time synchronization is needed in realtime applications of wireless sensor networks. While several synchronization protocols have been proposed, most performance evaluations have been limited to theoretical analysis and simulation, with a high level of abstraction by ignoring several practical aspects, e.g. packet handling jitters, clock drifting, packet loss, etc. Effective implementation in real motes faces several challenges due to motes' limitations and the unreliable lossy channels. These issues affect the protocol performance and precision. Authors of some pragmatic solutions followed empirical approaches for the evaluation, where the proposed solutions have been implemented on real motes and evaluated in testbed experiments. While there are several survey articles presenting the protocols from the conception perspectives, and others dealing with mathematical and signal processing issues of the estimators, a survey on aspects related to the practical implementation is missing. This article throws light on issues related to the implementation of synchronization protocols in WSN. The challenges related to WSN environment are presented, the importance of real implementation and the testbed evaluation are motivated by some experiments that we conducted. Finally, some relevant implementations of the literature that meet microsecond-level precision are discussed.
Information Security in Wireless Sensor Networks
(World Scientific, 2009-10) Ouadjaout, Abdelraouf; Bagaa, Miloud; Bachir, Abdelmalik; Challal, Yacine; Lasla, Noureddine; Khelladi, Lyes
In this chapter, we provide a comprehensive survey of security issues in wireless sensor networks. We show that the main features of WSNs, namely their limited resources, wireless communications, and close physical coupling with environment, are the main causes of the their security vulnerabilities. We discuss the main attacks stemming from these vulnerabilities, along with the solutions proposed in the literature to cope with them. The security solutions are analyzed with respect to the different layers of the network protocol stack and cover the following issues: Key management, secure data dissemination, secure data aggregation, secure channel access and secure node compromise.
Interference-aware Congestion Control Protocol for Wireless Sensor Networks
(Elsevier, 2014-09) Kafi, Mohamed Amine; Djenouri, Djamel; Ben Othman, Jalel; Ouadjaout, Abdelraouf; Bagaa, Miloud; Lasla, Noureddine; Badache, Nadjib
This paper deals with congestion and interference control in wireless sensor networks (WSN), which is essential for improving the throughput and saving the scarce energy in networks where nodes have different capacities and traffic patterns. A scheme called IACC (Interference-Aware Congestion Control) is proposed. It allows maximizing link capacity utilization for each node by controlling congestion and interference. This is achieved through fair maximum rate control of interfering nodes in inter and intra paths of hot spots. The proposed protocol has been evaluated by simulation, where the results rival the effectiveness of our scheme in terms of energy saving and throughput. In particular, the results demonstrate the protocol scalability and considerable reduction of packet loss that allow to achieve as high packet delivery ratio as 80% for large networks.
Interference-Aware Congestion Control Protocol for Wireless Sensor Networks
(CERIST, 2014-07-07) Kafi, Mohamed Amine; Djenouri, Djamel; Ben Othman, Jalel; Ouadjaout, Abdelraouf; Bagaa, Miloud; Lasla, Noureddine; Badache, Nadjib
This paper deals with congestion and interference control in wireless sensor networks (WSN), which is essential for improving the throughput and saving the scarce energy in networks where nodes have di erent capacities and tra c patterns. A scheme called IACC (Interference-Aware Congestion Control ) is proposed. It allows maximizing link capacity utilization for each node by controlling congestion and interference. This is achieved through fair maximum rate control of interfering nodes in inter and intra paths of hot spots. The proposed protocol has been evaluated by simulation, where the results rival the e ectiveness of our scheme in terms of energy saving and throughput. In particular, the results demonstrate the protocol scalability and considerable reduction of packet loss that allows to achieve as high packet delivery ratio as 80% for large networks.
Intertwined Medium Access Scheduling of Upstream and Downstream Traffic in Wireless Sensor Networks
(CERIST, 2013-12-25) Bagaa, Miloud; Younis, Mohamed; Djenouri, Djamel; Badache, Nadjib
In wireless sensor networks, the sensor data are often aggregated en-route to the base-station in order to eliminate redundancy and conserve the network resources. The base-station not only acts as a destination for the upstream data traffic, but it also configures the network by transmit- ting commands downstream to nodes. The data delivery latency is a critical performance metric in time-sensitive applications and is considered by a number of data aggregation schemes in the literature. However, to the best of our knowledge, no solution has considered the scheduling of downstream packets, originated from the base-station, in conjunction with upstream traffic. This paper fills such a gap and proposes MASAUD, which intertwines the medium access schedule of upstream and downstream traffic in order to reuse time slots in a non-conflicting manner and reduce delay. MASAUD can be integrated with any scheme for data aggregation scheduling. The simulation confirms the effectiveness of MASAUD.

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