6,204 research outputs found

    Probabilistic Routing Protocol for Intermittently Connected Networks

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    This document is a product of the Delay Tolerant Networking Research Group and has been reviewed by that group. No objections to its publication as an RFC were raised. This document defines PRoPHET, a Probabilistic Routing Protocol using History of Encounters and Transitivity. PRoPHET is a variant of the epidemic routing protocol for intermittently connected networks that operates by pruning the epidemic distribution tree to minimize resource usage while still attempting to achieve the best-case routing capabilities of epidemic routing. It is intended for use in sparse mesh networks where there is no guarantee that a fully connected path between the source and destination exists at any time, rendering traditional routing protocols unable to deliver messages between hosts. These networks are examples of networks where there is a disparity between the latency requirements of applications and the capabilities of the underlying network (networks often referred to as delay and disruption tolerant). The document presents an architectural overview followed by the protocol specification

    The Evolution of a DTN Routing Protocol - PRoPHETv2

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    Research within Delay- and Disruption Tolerant Networks (DTN) has evolved into a mature research area. PRoPHET is a routing protocol for DTNs that was developed when DTN research was in its infancy and which has been studied by many. In this paper we investigate how the protocol can evolve to meet new challenges that has been identified through research and practical experience. We propose some minor modifications to the routing metric cal- culations done in PRoPHET which has potential to alleviate some issues and improve the performance of the protocol. Using these modifications, we define an updated version of the protocol called PRoPHETv2. We run simulations to verify the operation of the protocol and compare its performance against the original version of the protocol as well as some other routing protocols. The evalua- tions are done using both traces from an existing DTN deployment and a synthetic mobility model. Since the basic mechanisms of the protocol remain the same, migrating existing implementations to the new version of PRoPHET is possible with limited effort

    On the inherent intractability of certain coding problems

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    The fact that the general decoding problem for linear codes and the general problem of finding the weights of a linear code are both NP-complete is shown. This strongly suggests, but does not rigorously imply, that no algorithm for either of these problems which runs in polynomial time exists

    Justice without Delay

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    Discordant harmonies and turbulent serenity : the ecopoetic rhythms of nature’s — and art’s — resistance

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    This article argues that the poetic and critical writings of Théodore de Banville represent a concerted and successful attempt to give the natural world an independent voice in literature. Ecocriticism calls for creative practices and reading strategies that refuse to see humankind as separate from nature, and allow it to resist any colonizing gestures that might presume to speak on its behalf. While the poetry of Lamartine, Hugo, Vigny and Leconte de Lisle features nature throughout, its ecopoetic potential is weakened by simplistic urban/rural oppositions that construct a nostalgic idyll as a refuge from industry, progress and society. Banville, however, places humankind at the heart of a nature pulsating with the restless energy of animistic spirits. Nature, for him, shares with genuine art an unassimilable quality. His writings on painting and poetry express this irreducible essence through interart analogies and oxymoron, while the verse of Les Exilés consistently places natural phenomena at points of tension between traditional cultural forms and a rebellious, unpredictable syntax.PostprintPeer reviewe

    Reindeer Range Appraisal In Alaska

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    Thesis (M.S.) University of Alaska Fairbanks, 196
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