1,721,141 research outputs found
Energy-conserving access protocols for identification networks
No full textA myriad of applications are emerging, in which energy conservation is a critical system parameter for communications. Radio frequency identification device (RFID) networks, smart cards, and even mobile computing devices, in general, need to conserve energy. In RFID systems, nodes are small battery-operated inexpensive devices with radio receiving/transmitting and processing capabilities, integrated into the size of an ID card or smaller. These identification devices are designed for extremely low-cost large-scale applications, such that the replacement of batteries is not feasible. This imposes a critical energy constraint on the communications (access) protocols used in these systems, so that the total time a node needs to be active for transmitting or receiving information should be minimized. Among existing protocols, classical random access protocols are not energy conserving, while deterministic protocols lead to unacceptable delays. This paper deals with designing communications protocols with energy constraint, in which the number of time slots in which tags need to be in the active state is minimized, while the access delay meets the applications constraints. We propose three classes of protocols which combine the fairness of random access protocols with low energy requirements
A mobility-transparent deterministic broadcast mechanism for Ad Hoc networks
No full textBroadcast (distributing a message from a source node to all other nodes) is a fundamental problem in distributed
computing. Several solutions for solving this problem in mobile wireless networks are available, in which mobility is dealt with either by the use of randomized retransmissions or, in the case of deterministic delivery protocols, by using conflict-free transmission schedules. Randomized solutions can be used only when unbounded delays can be tolerated. Deterministic conflictfree solutions require schedule recomputation when topology changes, thus becoming unstable when the topology rate of
change exceeds the schedule recomputation rate. The deterministic broadcast protocols we introduce in this paper overcome the above limitations by using a novel mobility-transparent schedule,
thus providing a delivery (time) guarantee without the need to
recompute the schedules when topology changes. We show that the proposed protocol is simple and easy to implement, and that it is optimal in networks in which assumptions on the maximum
number of the neighbors of a node can be made
BlueMesh: Degree-Constrained MultiHop Scatternet Formation for Bluetooth Networks
No full textIn this paper we describe BlueMesh, a new protocol for the establishment of scatternets, i.e., multi-hop wireless networks of Bluetooth devices. BlueMesh defines rules for device discovery, piconet formation and piconet interconnection so to generate connected scatternets with the following desirable properties. BlueMesh forms scatternets without requiring the Bluetooth devices to be all in each other transmission range. BlueMesh scatternet topologies are meshes with multiple paths between any pair of nodes. BlueMesh piconets are made up of no more than 7 slaves. Simulation results in networks with over 200 nodes show that BlueMesh is effective in quickly generating a connected scatternet in which each node, on average, does not assume more than 2.4 roles. Moreover, the route length between any two nodes in the network is comparable to that of the shortest paths between the nodes
CATO: trans-layer dense wavelength-division multiplexing (DWDM) network optimization. The clustering approach for large network design
No full textDWDM network optimization and management problems include routing and wavelength assignment, protection switching, and resource allocation. A novel reduction technique in conjunction with a tested design tool, CATO, allows optimization of significantly larger network
Configuring BlueStars: Multihop scatternet formation for Bluetooth networks
No full textThis paper describes a new protocol for the establishment of multihop ad hoc networks based on Bluetooth devices. The protocol proceeds in three phases: device discovery, partitioning of the network into Bluetooth piconets, and interconnection of the piconets into a connected scatternet The protocol has the following desirable properties: It is executed at each node with no prior knowledge of the network topology, thus being fully distributed. The selection of the Bluetooth masters is driven by the suitability of a node to be the "best fit" for serving as a master. The generated scatternet is a connected mesh with multiple paths between any pair of nodes, thus achieving robustness. Differently from existing solutions, no extra hardware is required to run the protocol at each node and there is no need for a designated node to start the scatternet formation process. Simulation results are provided which evaluate the impact of the Bluetooth device discovery phase on the performance of the protocol
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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