1,875 research outputs found

    Localized Support for Injection Point Election in Hybrid Networks

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    Ad-hoc networks, a promising trend in wireless technology, fail to work properly in a global setting. In most cases, self-organization and cost-free local communication cannot compensate the need for being connected, gathering urgent information just-in-time. Equipping mobile devices additionally with GSM or UMTS adapters in order to communicate with arbitrary remote devices or even a fixed network infrastructure provides an opportunity. Devices that operate as intermediate nodes between the ad-hoc network and a reliable backbone network are potential injection points. They allow disseminating received information within the local neighborhood. The effectiveness of different devices to serve as injection point differs substantially. For practical reasons the determination of injection points should be done locally, within the ad-hoc network partitions. We analyze different localized algorithms using at most 2-hop neighboring information. Results show that devices selected this way spread information more efficiently through the ad-hoc network. Our results can also be applied in order to support the election process for clusterheads in the field of clustering mechanisms.Comment: The Sixth International Conference on Networking (ICN 2007

    Multimedia Content Distribution in Hybrid Wireless Networks using Weighted Clustering

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    Fixed infrastructured networks naturally support centralized approaches for group management and information provisioning. Contrary to infrastructured networks, in multi-hop ad-hoc networks each node acts as a router as well as sender and receiver. Some applications, however, requires hierarchical arrangements that-for practical reasons-has to be done locally and self-organized. An additional challenge is to deal with mobility that causes permanent network partitioning and re-organizations. Technically, these problems can be tackled by providing additional uplinks to a backbone network, which can be used to access resources in the Internet as well as to inter-link multiple ad-hoc network partitions, creating a hybrid wireless network. In this paper, we present a prototypically implemented hybrid wireless network system optimized for multimedia content distribution. To efficiently manage the ad-hoc communicating devices a weighted clustering algorithm is introduced. The proposed localized algorithm deals with mobility, but does not require geographical information or distances.Comment: 2nd ACM Workshop on Wireless Multimedia Networking and Performance Modeling 2006 (ISBN 1-59593-485

    Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall

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    For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des.82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T, leading up to 2020 and the first experiments with 50%/50% D–T mixtures since 1997 and the first ever D–T plasmas with the ITER mix of plasma-facing component materials. For this purpose, a concerted physics and technology programme was launched with a view to prepare the D–T campaign (DTE2). This paper addresses the key elements developed by the JET programme directly contributing to the D–T preparation. This intense preparation includes the review of the physics basis for the D–T operational scenarios, including the fusion power predictions through first principle and integrated modelling, and the impact of isotopes in the operation and physics of D–T plasmas (thermal and particle transport, high confinement mode (H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving several aspects of plasma operation for DTE2, such as real time control schemes, heat load control, disruption avoidance and a mitigation system (including the installation of a new shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the three-ions scheme), new diagnostics (neutron camera and spectrometer, active Alfvèn eigenmode antennas, neutral gauges, radiation hard imaging systems...) and the calibration of the JET neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation of JET for the 2020 D–T campaign provides an incomparable source of information and a basis for the future D–T operation of ITER, and it is also foreseen that a large number of key physics issues will be addressed in support of burning plasmas.This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 and 2019–2020 under grant agreement No. 633053Postprint (published version

    High Stakes Institutional Translation: Establishing North America’s First Government-Sanctioned Supervised Injection Site

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    Around the world, potentially effective responses to serious social problems are left untried because those responses are politically, culturally or morally problematic in affected communities. I describe the process through which communities import such practices as “high-stakes institutional translation”. Drawing on a study of North America’s first supervised injection site for users of illegal drugs, I propose a process model of high-stakes institutional translation that involves a triggering period of public expressions of intense emotion, followed by waves of translations in which the controversial practice is constructed in discursive and material terms many times over

    HyCast-Podcast Discovery in Mobile Networks

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    Podcasts are a popular way to provide multimedia information about certain topics. A multitude of podcast servers exist in the Internet, allowing people to subscribe to them. Typically, podcasts are downloaded onto desktop computers and copied on mobile devices to be played while being on the move. In this paper, we extend the idea of podcasts, making them available in mobile network environments. In particular, HyCast does not rely on central podcast directories. Instead, HyCast also allows discovering, subscribing to, and downloading podcasts and episodes in the local neighborhood. For the dissemination of podcast information, we introduce and evaluate two different strategies. One is based on peer-to-peer communication between one-hop neighbors. The second one employs clustering to reduce the overhead of the podcast information dissemination

    Countering Terrorism on Tomorrow’s Battlefield: Critical Infrastructure Security and Resiliency (NATO COE-DAT Handbook 2)

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    Every day, malicious actors target emerging technologies and medical resilience or seek to wreak havoc in the wake of disasters brought on by climate change, energy insecurity, and supply-chain disruptions. Countering Terrorism on Tomorrow’s Battlefield is a handbook on how to strengthen critical infrastructure resilience in an era of emerging threats. The counterterrorism research produced for this volume is in alignment with NATO’s Warfighting Capstone Concept, which details how NATO Allies can transform and maintain their advantage despite new threats for the next two decades. The topics are rooted in NATO’s Seven Baseline requirements, which set the standard for enhancing resilience in every aspect of critical infrastructure and civil society. As terrorists hone their skills to operate lethal drones, use biometric data to target innocents, and take advantage of the chaos left by pandemics and natural disasters for nefarious purposes, NATO forces must be prepared to respond and prevent terrorist events before they happen. Big-data analytics provides potential for NATO states to receive early warning to prevent pandemics, cyberattacks, and kinetic attacks. NATO is perfecting drone operations through interoperability exercises, and space is being exploited by adversaries. Hypersonic weapons are actively being used on the battlefield, and satellites have been targeted to take down wind farms and control navigation. This handbook is a guide for the future, providing actionable information and recommendations to keep our democracies safe today and in the years to come.https://press.armywarcollege.edu/monographs/1953/thumbnail.jp

    The epistemological challenge of truth-subversion to the Liberal International Order

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    Truth-subversion practices, which populist leaders utilize for political domination, are a significant source of current pressure on the Liberal International Order (LIO). Truth-subversion practices include false speak (flagrant lying to subvert the concept of facts), double speak (intentional internal contradictions in speech to erode reason), and flooding (the emission of many messages into the public domain to create confusion). Aiming to destroy liberal truth ideals and practices, truth subversion weakens epistemological security; that is, the experience of orderliness and safety that results from people's and institutions’ shared understandings of their common-sense reality. It privileges baseless claims over fact-based opinions, thus creating communities of the like-minded between which communication becomes impossible. Truth subversion challenges the LIO's three key institutions: democracy, markets, and multilateralism. If truth-subversion practices prevail, societal polarization, inaccurate information, and emotional inflaming strain democracy and human rights protections. Markets that depend for their functioning on accurate information can falter, and multilateralism that relies on communication and reasoned consensus can decay. International relations (IR) scholarship has recognized knowledge production practices as a key feature underlying the LIO, but has not yet identified challenges to those practices as a threat for the LIO. We discuss what the discipline can do to alleviate its blind spots
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