Search results for "routing"
showing 10 items of 587 documents
Lifespan-Aware Routing for Wireless Sensor Networks
2010
Wireless Sensor Networks (WSNs) have the capability to become the eyes and ears for the future networked society allowing monitoring of any habitat or object's properties remotely and independently of an energy source. Services based on this technology may change the way we monitor and control remote areas and objects. In this paper we propose a different approach to routing data across Wireless Sensor Networks. We argue that a distance-vector protocol using a lifespan-aware metric is a plausible solution to the task of routing information in WSN in a manner that both saves energy of the individual node and manages summarized energy of the system equally and fairly. The concept is designed …
Stability Analysis of Routing Strategies for the Maximum Lifetime Problem in One-Dimensional Ad-Hoc Wireless Networks
2017
In the paper we discuss solutions of the maximum network lifetime problem in one-dimensional, regular ad-hoc wireless networks. For the problem, nodes of the network generate given amount of data and send it possibly via other nodes to the data collector. To extend the network lifetime the data should be transmitted in such a way, that the energy utilized by the most overloaded node is minimized. We assume, that the nodes use the point-to-point data transmission scheme and the cost of transmission of one unit of data is arbitrary superadditive function of a distance between transmitter and receiver. We show that for the one-dimensional network in which the nodes are evenly distributed on th…
A Branch-and-Cut method for the Capacitated Location-Routing Problem
2011
International audience; Recent researches in the design of logistic networks have shown that the overall distribution cost may be excessive if routing decisions are ignored when locating depots. The Location-Routing Problem (LRP) overcomes this drawback by simultaneously tackling location and routing decisions. The aim of this paper is to propose an exact approach based on a Branch-and-Cut algorithm for solving the LRP with capacity constraints on depots and vehicles. The proposed method is based on a zero-one linear model strengthened by new families of valid inequalities. The computational evaluation on three sets of instances (34 instances in total), with 5–10 potential depots and 20–88 …
TBRA: A scalable routing algorithm in highly mobile large scale pure ad hoc wireless mesh networks
2009
In highly mobile pure ad-hoc wireless mesh networks, fast rerouting within low routing discovery delay is a mandatory requirement for routing algorithm to support interactive applications such as VoIP. Also, the communication overhead should be thwarted when networks grow to a large scale. We propose a Tree-Based Routing Algorithm - TBRA to facilitate such two goals. On one hand, TBRA has very low routing discovery delay due to its proactive property. On the other hand, TBRA performs more efficiently than other proactive protocols with respect to low communication overhead, which thanks to its short routing packet length, less numbers and smaller routing table size. Our modeling analysis an…
A flexible and tunable route discovery mechanism for on-demand protocols
2004
Mobile ad-hoc networks are characterized by multihop wireless links and absence of cellular infrastructure. For the last years, routing has been the area under most intensive research. In particular, on-demand routing protocols proposed are extremely attractive due to their low-overhead and efficiency. Currently, wireless ad-hoc networks lack multipath routing protocols. Multipath routing enables increased QoS support, load balancing and enhanced route stability. In this paper we present a new route discovery solution that increases the number of routes found, while reducing the routing overhead when compared to previous proposals. Simulation results show that the additional routing overhea…
Logic-Based Distributed Routing for NoCs
2008
The design of scalable and reliable interconnection networks for multicore chips (NoCs) introduces new design constraints like power consumption, area, and ultra low latencies. Although 2D meshes are usually proposed for NoCs, heterogeneous cores, manufacturing defects, hard failures, and chip virtualization may lead to irregular topologies. In this context, efficient routing becomes a challenge. Although switches can be easily configured to support most routing algorithms and topologies by using routing tables, this solution does not scale in terms of latency and area. We propose a new circuit that removes the need for using routing tables. The new mechanism, referred to as logic-based dis…
In-Depth Analysis of Pricing Problem Relaxations for the Capacitated Arc-Routing Problem
2015
Recently, Bode and Irnich [Bode C, Irnich S (2012) Cut-first branch-and-price-second for the capacitated arc-routing problem. Oper. Res. 60(5):1167–1182] presented a cut-first branch-and-price-second algorithm for solving the capacitated arc-routing problem (CARP). The fundamental difference to other approaches for exactly solving the CARP is that the entire algorithm works directly on the typically sparse underlying graph representing the street network. This enables the use of highly efficient dynamic programming-based pricing algorithms to solve the column-generation subproblem also known as the pricing problem. The contribution of this paper is the in-depth analysis of the CARP pricing…
The Capacitated Arc Routing Problem: Lower bounds
1992
In this paper, we consider the Capacitated Arc Routing Problem (CARP), in which a fleet of vehicles, based on a specified vertex (the depot) and with a known capacity Q, must service a subset of the edges of a graph, with minimum total cost and such that the load assigned to each vehicle does not exceed its capacity. New lower bounds are developed for this problem, producing at least as good results as the already existing ones. Three of the proposed lower bounds are obtained from the resolution of a minimum cost perfect matching problem. The fourth one takes into account the vehicle capacity and is computed using a dynamic programming algorithm. Computational results, in which these bounds…
Effective Handling of Dynamic Time Windows and Its Application to Solving the Dial-a-Ride Problem
2015
A dynamic time window relates to two operations that must be executed within a given time meaning that the difference between the points in time when the two operations are performed is bounded from above. The most prevalent context of dynamic time windows is when precedence is given for the two operations so that it is a priori specified that one operation must take place before the other. A prominent vehicle routing problem with dynamic time windows and precedence is the dial-a-ride problem (DARP), where user-specified transportation requests from origin to destination points must be serviced. The paper presents a new branch-and-cut-and-price solution approach for the DARP, the prototypi…
Resistant Microbial Cooccurrence Patterns Inferred by Network Topology
2015
ABSTRACT Although complex cooccurrence patterns have been described for microbes in natural communities, these patterns have scarcely been interpreted in the context of ecosystem functioning and stability. Here we constructed networks from species cooccurrences between pairs of microorganisms which were extracted from five individual aquatic time series, including a dystrophic and a eutrophic lake as well as an open ocean site. The resulting networks exhibited higher clustering coefficients, shorter path lengths, and higher average node degrees and levels of betweenness than those of random networks. Moreover, simulations demonstrated that taxa with a large number of cooccurrences and place…