End-to-End Energy Efficient Geographic Path Discovery With Guaranteed Delivery in Ad Hoc and Sensor Networks

International audienceWe propose a novel localized routing protocol for wireless sensor networks (WSN) that is energy-efficient and guarantees delivery. We prove that it is constant factor of the optimum for dense networks. To forward a packet, a node $s$ in graph $G$ computes the cost of the energy weighted shortest path (SP) between $s$ and each of its neighbors which are closer to the destination than itself. It then selects node $x$ which minimizes the ratio of the cost of the SP to the progress towards the destination. It then sends the message to the first node on the SP from $s$ to $x$: say node $x'$. Node $x'$ restarts the same greedy routing process until the destination is reached or the routing fails. To recover from failure, our algorithm invokes Face routing that guarantees delivery. This work is the first to optimize energy consumption of Face routing. First, we build a connected dominating set from graph $G$, second we compute its Gabriel graph to obtain the planar graph $G'$. Face routing is applied on $G'$ only to decide which edges to follow in the recovery process. On each edge, greedy routing is used. This two-phase (greedy-Face) End-to-End routing process (EtE) reiterates until the final destination is reached. Simulation results show that EtE outperforms several existing geographical routing on energy consumption metric

Cost over Progress Based Energy Efficient Routing over Virtual Coordinates in Wireless Sensor Networks

International audienceWe propose an energy efficient routing protocol, VCost, for sensor networks. We assume that nodes are unaware of their geographic location thus, VCost assigns virtual coordinates to nodes as follows. Based on the node hop count distances from a set of landmarks, our method computes a distance metric to obtain the node's virtual coordinates. VCost, then uses these coordinates to route packets from node u to node v, in its neighborhood, such that the ratio of the cost to send a message to v to the progress in the routing task towards the destination is minimized. Compared to existing algorithms that use virtual locations, our simulation shows that VCost improves significantly energy consumption and preserves the small percentage of successful routings

Energy Efficient Multi-Flow Routing in Mobile Sensor Networks.

International audienceControlled mobility is one of the most complex challenges in Wireless Sensor Networks (WSN). Only a few routing protocols consider controlled mobility in order to extend the network lifetime. They are all designed to optimize the physical route topology from a source to a destination. However, there is often more than one sensor which reports an event to the sink in WSN. In existing solutions, this leads to oscillation of nodes which belong to different routes and their premature death. Experiments show that the need of a routing path merge solution is high. As a response we propose the first routing protocol which locates and uses paths crossing to adapt the topology to the network traffic in a fully localized way while still optimizing energy efficiency. Furthermore the protocol makes the intersection to move away from the destination, getting closer to the sources, allowing higher data aggregation and energy saving. Our approach outperforms existing solutions and extends network lifetime up to 37%

Energy-aware Georouting with Guaranteed Delivery in Wireless Sensor Networks with Obstacles

International audienceWe propose, EtE, a novel end-to-end localized routing protocol for wireless sensor networks that is energy-efficient and guarantees delivery. To forward a packet, a node s in graph G computes the cost of the energy weighted shortest path between s and each of its neighbors in the forward direction towards the destination which minimizes the ratio of the cost of the shortest path to the progress (reduction in distance towards the destination). It then sends the message to the first node on the shortest path from s to x: say node x′. Node x′ restarts the same greedy rout- ing process until the destination is reached or an obstacle is encountered and the routing fails. To recover from the latter scenario, local minima trap, our algorithm invokes an energy-aware Face routing that guarantees delivery. Our work is the first to optimize energy consumption of Face routing. It works as follows. First, it builds a connected dominating set from graph G, second it computes its Gabriel graph to obtain the planar graph G′. Face routing is invoked and applied to G′ only to determine which edges to follow in the recovery process. On each edge, greedy rout- ing is applied. This two-phase (greedy-Face) End-to-End routing process (EtE) reiterates until the final destination is reached. Simulation results show that EtE outperforms several existing geographical routing on en- ergy consumption metric and delivery rate. Moreover, we prove that the computed path length and the total energy of the path are constant factors of the optimal for dense networks

A Novel Decomposition-Based Method for Solving General-Product Structure Assemble-to-Order Systems

10.1016/j.ejor.2020.03.01

Optimal production and inventory control of multi-class mixed backorder and lost sales demand class models

10.1016/j.ejor.2020.09.009European Journal of Operational Research2911147-16

Minimising Energy Consumption through Mobility with Connectivity preservation in Sensor Networks

International audienceIn typical mobile wireless sensor networks, flows sent from collecting sensors to a sink could traverse inefficient resource expensive paths and experience arbitrary delays. This is par- ticularly problematic in event-based sensor network where flows are of great importance. In this paper, we are interested in energy-aware routing algorithms that explicitly take ad- vantage of node mobility to improve energy consumption of computed paths. Mobility is a two-sword edge however. Moving a node may render the network disconnected and results in early termination of information delivery. To mitigate these problems, we propose a family of routing algorithm called CoMNet (Connectivity preservation Mobile routing protocols for actuator and sensor NETworks), that uses local information and modifies the network topol- ogy to support resource efficient transmissions. Our extensive simulations show that CoMNet has high energetic performance improvement compared to existing routing algorithms. More importantly, we show that CoMNet guarantees network connectivity and efficient resource consumption