[Show abstract][Hide abstract] ABSTRACT: As applications in Wireless Sensor Networks are evolving, performance bounds are becoming stricter. Novel ap- plications introduce much heavier traffic load, which, in turn, leads specific areas in the network to face congestion problems. In this paper, we describe the notion of using mobile nodes to mitigate congestion under specific circumstances. We examine the benefits of introducing new mobile nodes placed between the congested areas and sinks, in order to provide alternative disjoint paths towards them. The proposed Mobile Congestion Control (Mobile-CC) algorithm is applicable in areas where congestion happens repeatedly, or is of high duration, or even permanent. If congestion happens for very small period of time there will be no big benefit (in terms of congestion mitigation) when moving any nodes to that area, unless there is great probability of the event happening again at the same place in the future. Mobile-CC is not replacing existing congestion control or routing algorithms but instead aims to mitigate congestion, running in parallel with them.
[Show abstract][Hide abstract] ABSTRACT: Plant automation and control are mission-critical applications and require timely and reliable data delivery, which is difficult to provide using a wireless technology. This is especially more difficult in industrial environments with harsh radio conditions. In this paper we present a dynamic and distributed topology control algorithm for Wireless Sensor Networks for use in performance critical environments. This topology control algorithm assumes a small number of sensor nodes connected to a single sink and communicating using a TDMA-based MAC protocol designed with the application requirements in mind. Our solution was implemented and evaluated in real testbed inside an oil refinery. Evaluation results demonstrating the self-organizing properties of the proposed mechanism, as well as its operational performance are included. The results show that the system reliability is high and that data are delivered on time to the control center.
[Show abstract][Hide abstract] ABSTRACT: When an event occurs in an area observed by a Wireless Sensor Network, a vast amount of information is transferred towards the sink(s) of the network. This phenomenon may sometimes result into network congestion and as a consequence packets may start dropping due to queue overflows. To our knowledge most proposed reactions to this phenomenon utilize only static nodes whereas a few utilize mobile sink(s). Our approach is focusing on using multiple mobile nodes to build Hard Alternate Disjoint Paths between some of the sources of the congested nodes and the sink(s) to mitigate congestion. Mobile Congestion Control (Mobile-CC) algorithm is applicable in areas where congestion happens repeatedly, or is of high duration or even permanent. If congestion happens for a very small period of time there will be no big benefit (in terms of congestion mitigation) when moving any nodes to that area, unless there is great probability of the event happening again at the same place.
[Show abstract][Hide abstract] ABSTRACT: Real deployments of wireless sensor networks (WSN) are rare, and virtually all have considerable limitations when the application in critical scenarios is concerned. On one side, research in WSNs tends to favour complex and non-realistic mechanisms and protocols and, on the other side, the responsible for the critical scenarios, such as the industry, still prefer well-known but expensive analog solutions. However, the aim of the GINSENG Project is to achieve the same reliability of WSNs that the conventional analog systems provide, by controlling the network per-formance. In this paper we present the GINSENG architecture and the platform that have been implemented in a real scenario, considered one of the most critical in the world: an Oil Refinery.