Task allocation to actors in wireless sensor actor networks: an energy and time aware technique

AbstractTask allocation is a critical issue in proper engineering of cooperative applications in embedded systems with latency and energy constraints, as in wireless sensor and actor networks (WSANs). Existing task allocation algorithms are mostly concerned with energy savings and ignore time constraints and thus increase the makespan of tasks in the network as well as the probability of malfunctioning of the network. In this paper we take both energy awareness and reduction of actor tasks’ times to completion in WSANs into account and propose a two-phase task allocation technique based on Queuing theory. In the first phase, tasks are equally assigned to actors just to measure the capability of each actor to perform the assigned tasks. Tasks are then allocated to actors according to their measured capabilities in such a way to reduce the total completion times of all tasks in the network. The results of simulations on typical scenarios shows 45% improvement in the makespan of tasks in a network compared to the wellknown opportunistic load balancing (OLB) task allocation algorithm that is generally used in distributed systems. It is shown that our algorithms provide better tradeoffs between load balancing and completion times of all tasks in a WSAN compared to OLB

Routing, Localization And Positioning Protocols For Wireless Sensor And Actor Networks

Wireless sensor and actor networks (WSANs) are distributed systems of sensor nodes and actors that are interconnected over the wireless medium. Sensor nodes collect information about the physical world and transmit the data to actors by using one-hop or multi-hop communications. Actors collect information from the sensor nodes, process the information, take decisions and react to the events. This dissertation presents contributions to the methods of routing, localization and positioning in WSANs for practical applications. We first propose a routing protocol with service differentiation for WSANs with stationary nodes. In this setting, we also adapt a sports ranking algorithm to dynamically prioritize the events in the environment depending on the collected data. We extend this routing protocol for an application, in which sensor nodes float in a river to gather observations and actors are deployed at accessible points on the coastline. We develop a method with locally acting adaptive overlay network formation to organize the network with actor areas and to collect data by using locality-preserving communication. We also present a multi-hop localization approach for enriching the information collected from the river with the estimated locations of mobile sensor nodes without using positioning adapters. As an extension to this application, we model the movements of sensor nodes by a subsurface meandering current mobility model with random surface motion. Then we adapt the introduced routing and network organization methods to model a complete primate monitoring system. A novel spatial cut-off preferential attachment model and iii center of mass concept are developed according to the characteristics of the primate groups. We also present a role determination algorithm for primates, which uses the collection of spatial-temporal relationships. We apply a similar approach to human social networks to tackle the problem of automatic generation and organization of social networks by analyzing and assessing interaction data. The introduced routing and localization protocols in this dissertation are also extended with a novel three dimensional actor positioning strategy inspired by the molecular geometry. Extensive simulations are conducted in OPNET simulation tool for the performance evaluation of the proposed protocol

QoS Challenges and Opportunities in Wireless Sensor/Actuator Networks

A wireless sensor/actuator network (WSAN) is a group of sensors and actuators that are geographically distributed and interconnected by wireless networks. Sensors gather information about the state of physical world. Actuators react to this information by performing appropriate actions. WSANs thus enable cyber systems to monitor and manipulate the behavior of the physical world. WSANs are growing at a tremendous pace, just like the exploding evolution of Internet. Supporting quality of service (QoS) will be of critical importance for pervasive WSANs that serve as the network infrastructure of diverse applications. To spark new research and development interests in this field, this paper examines and discusses the requirements, critical challenges, and open research issues on QoS management in WSANs. A brief overview of recent progress is given.Comment: 12 pages, 1 figure; revie

Self-Organizing Mobility Control in Wireless Sensor and Actor Networks Based on Virtual Electrostatic Interactions

This paper introduces a new mobility control method for surveillance applications of wireless sensor and actor networks. The proposed method is based on virtual electrostatic forces which act on actors to coordinate their movements. The definition of virtual forces is inspired by Coulomb’s law from physics. Each actor calculates the virtual forces independently based on known locations of its neighbours and predetermined borders of the monitored area. The virtual forces generate movements of actors. This approach enables effective deployment of actors at the initial stage as well as adaptation of actors’ placement to variable conditions during execution of the surveillance task without the need of any central controller. Effectiveness of the introduced method was experimentally evaluated in a simulation environment. The experimental results demonstrate that the proposed method enables more effective organization of the actors’ mobility than state-of-the-art approaches

Efficient Actor Recovery Paradigm For Wireless Sensor And Actor Networks

Wireless sensor networks (WSNs) are becoming widely used worldwide. Wireless Sensor and Actor Networks (WSANs) represent a special category of WSNs wherein actors and sensors collaborate to perform specific tasks. WSANs have become one of the most preeminent emerging type of WSNs. Sensors with nodes having limited power resources are responsible for sensing and transmitting events to actor nodes. Actors are high-performance nodes equipped with rich resources that have the ability to collect, process, transmit data and perform various actions. WSANs have a unique architecture that distinguishes them from WSNs. Due to the characteristics of WSANs, numerous challenges arise. Determining the importance of factors usually depends on the application requirements. The actor nodes are the spine of WSANs that collaborate to perform the specific tasks in an unsubstantiated and uneven environment. Thus, there is a possibility of high failure rate in such unfriendly scenarios due to several factors such as power fatigue of devices, electronic circuit failure, software errors in nodes or physical impairment of the actor nodes and inter-actor connectivity problem. It is essential to keep inter-actor connectivity in order to insure network connectivity. Thus, it is extremely important to discover the failure of a cut-vertex actor and network-disjoint in order to improve the Quality-of-Service (QoS). For network recovery process from actor node failure, optimal re-localization and coordination techniques should take place. In this work, we propose an efficient actor recovery (EAR) paradigm to guarantee the contention-free traffic-forwarding capacity. The EAR paradigm consists of Node Monitoring and Critical Node Detection (NMCND) algorithm that monitors the activities of the nodes to determine the critical node. In addition, it replaces the critical node with backup node prior to complete node-failure which helps balances the network performance. The packet is handled using Network Integration and Message Forwarding (NIMF) algorithm that determines the source of forwarding the packets (Either from actor or sensor). This decision-making capability of the algorithm controls the packet forwarding rate to maintain the network for longer time. Furthermore, for handling the proper routing strategy, Priority-Based Routing for Node Failure Avoidance (PRNFA) algorithm is deployed to decide the priority of the packets to be forwarded based on the significance of information available in the packet. To validate the effectiveness of the proposed EAR paradigm, we compare the performance of our proposed work with state-of the art localization algorithms. Our experimental results show superior performance in regards to network life, residual energy, reliability, sensor/ actor recovery time and data recovery

Task Allocation among Connected Devices: Requirements, Approaches and Challenges

Task allocation (TA) is essential when deploying application tasks to systems of connected devices with dissimilar and time-varying characteristics. The challenge of an efficient TA is to assign the tasks to the best devices, according to the context and task requirements. The main purpose of this paper is to study the different connotations of the concept of TA efficiency, and the key factors that most impact on it, so that relevant design guidelines can be defined. The paper first analyzes the domains of connected devices where TA has an important role, which brings to this classification: Internet of Things (IoT), Sensor and Actuator Networks (SAN), Multi-Robot Systems (MRS), Mobile Crowdsensing (MCS), and Unmanned Aerial Vehicles (UAV). The paper then demonstrates that the impact of the key factors on the domains actually affects the design choices of the state-of-the-art TA solutions. It results that resource management has most significantly driven the design of TA algorithms in all domains, especially IoT and SAN. The fulfillment of coverage requirements is important for the definition of TA solutions in MCS and UAV. Quality of Information requirements are mostly included in MCS TA strategies, similar to the design of appropriate incentives. The paper also discusses the issues that need to be addressed by future research activities, i.e.: allowing interoperability of platforms in the implementation of TA functionalities; introducing appropriate trust evaluation algorithms; extending the list of tasks performed by objects; designing TA strategies where network service providers have a role in TA functionalities’ provisioning

Development of Energy and Delay Efficient Protocols for WSAN

Wireless sensor-actor network (WSAN) is a collection of resource conservative sensors and few resource-rich actors. It is widely used in various applications such as environmental monitoring, battlefield surveillance, industrial process control, and home applications. In these real-time applications, data should be delivered with minimum delay and energy. In this thesis, delay and energy efficient protocols are designed to achieve these objectives. The first contribution proposes a delay and energy aware coordination protocol (DEACP) to improve the network performance. It consists of two-level hierarchical K-hop clustering and backup cluster head (BCH) selection mechanism to provide coordination among sensors and actors. Further, a priority based event forwarding mechanism has also been proposed to forward the maximum number of packets within the bounded delay. The simulation results demonstrate the effectiveness of DEACP over existing protocols. In the second work, an interference aware multi-channel MAC protocol (IAMMAC) has been suggested to assign channels for the communication among nodes in the DEACP. An actor assigns the static channels to all of its cluster members for sensor-sensor and sensor-actor coordination. Subsequently, a throughput based dynamic channel selection mechanism has been developed for actor-actor coordination. It is inferred from the simulation results that the proposed IAMMAC protocol outperforms its competitive protocols. Even though its performance is superior, it is susceptible to be attacked because it uses a single static channel between two sensors in the entire communication. To overcome this problem, a lightweight dynamic multi-channel MAC protocol (DM-MAC) has been designed for sensor sensor coordination. Each sensor dynamically selects a channel which provides maximum packet reception ratio among the available hannels with the destination. The comparative analysis shows that DM-MAC protocol performs better than the existing MAC protocols in terms of different performance parameters. WSAN is designed to operate in remote and hostile environments and hence, sensors and actors are vulnerable to various attacks. The fourth contribution proposes a secure coordination mechanism (SCM) to handle the data forwarding attacks in DEACP. In the SCM, each sensor computes the trust level of its neighboring sensors based on the experience, recommendation, and knowledge. The actor analyzes the trust values of all its cluster members to identify the malicious node. Secure hash algorithm-3 is used to compute the message authentication code for the data. The sensor selects a neighbor sensor which has the highest trust value among its 1-hop sensors to transfer data to the actor. The SCM approach outperforms the existing security mechanisms