1,206 research outputs found

    ADN: An Information-Centric Networking Architecture for the Internet of Things

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    Forwarding data by name has been assumed to be a necessary aspect of an information-centric redesign of the current Internet architecture that makes content access, dissemination, and storage more efficient. The Named Data Networking (NDN) and Content-Centric Networking (CCNx) architectures are the leading examples of such an approach. However, forwarding data by name incurs storage and communication complexities that are orders of magnitude larger than solutions based on forwarding data using addresses. Furthermore, the specific algorithms used in NDN and CCNx have been shown to have a number of limitations. The Addressable Data Networking (ADN) architecture is introduced as an alternative to NDN and CCNx. ADN is particularly attractive for large-scale deployments of the Internet of Things (IoT), because it requires far less storage and processing in relaying nodes than NDN. ADN allows things and data to be denoted by names, just like NDN and CCNx do. However, instead of replacing the waist of the Internet with named-data forwarding, ADN uses an address-based forwarding plane and introduces an information plane that seamlessly maps names to addresses without the involvement of end-user applications. Simulation results illustrate the order of magnitude savings in complexity that can be attained with ADN compared to NDN.Comment: 10 page

    Understanding the spatial pattern of urban crime: a developing country's perspective

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    Much of the published spatial analysis research of crime to date has been focused on Euro-American cities. This paper attempts to provide an insight on how we can better understand the spatial pattern of crime in a typical developing country’s setting. Data were obtained through extensive field mapping, a block environmental inventory (BEI) and a crime victimization survey to generate a GIS-database of the study area. Grid thematic maps (GTM) for different crime types were produced for visual analysis, which suggests, as observed in many Euro-American studies, crime clusters geographically

    Recovering a lost baseline: missing kelp forests from a metropolitan coast

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    © 2008 AuthorThere is concern about historical and continuing loss of canopy-forming algae across the world’s temperate coastline. In South Australia, the sparse cover of canopy-forming algae on the Adelaide metropolitan coast has been of public concern with continuous years of anecdotal evidence culminating in 2 competing views. One view considers that current patterns existed before the onset of urbanisation, whereas the alternate view is that they developed after urbanisation. We tested hypotheses to distinguish between these 2 models, each centred on the reconstruction of historical covers of canopies on the metropolitan coast. Historically, the metropolitan sites were indistinguishable from contemporary populations of reference sites across 70 km (i.e. Gulf St. Vincent), and could also represent a random subset of exposed coastal sites across 2100 km of the greater biogeographic province. Thus there was nothing ‘special’ about the metropolitan sites historically, but today they stand out because they have sparser covers of canopies compared to equivalent locations and times in the gulf and the greater province. This is evidence of wholesale loss of canopy-forming algae (up to 70%) on parts of the Adelaide metropolitan coast since major urbanisation. These findings not only set a research agenda based on the magnitude of loss, but they also bring into question the logic that smaller metropolitan populations of humans create impacts that are trivial relative to that of larger metropolitan centres. Instead, we highlight a need to recognise the ecological context that makes some coastal systems more vulnerable or resistant to increasing human-domination of the world’s coastlines. We discuss challenges to this kind of research that receive little ecological discussion, particularly better leadership and administration, recognising that the systems we study out-live the life spans of individual research groups and operate on spatial scales that exceed the capacity of single research providers.Sean D. Connell, Bayden D. Russell, David J. Turner, Scoresby A. Shepherd, Timothy Kildea, David Miller, Laura Airoldi, Anthony Cheshir

    Copyright Notice

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    IAB Thoughts on Encodings for Internationalized Domain Names This document explores issues with Internationalized Domain Names (IDNs) that result from the use of various encoding schemes such as UTF-8 and the ASCII-Compatible Encoding produced by the Punycode algorithm. It focuses on the importance of agreeing on a single encoding and how complicated the state of affairs ends up being as a result of using different encodings today. Status of This Memo This document is not an Internet Standards Track specification; it is published for informational purposes. This document is a product of the Internet Architecture Board (IAB) and represents information that the IAB has deemed valuable to provide for permanent record. Documents approved for publication by the IAB are not a candidate for any level of Internet Standard; see Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained a

    Hydrogen atom in phase space: The Wigner representation

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    We have found an effective method of calculating the Wigner function, being a quantum analogue of joint probability distribution of position and momentum, for bound states of nonrelativistic hydrogen atom. The formal similarity between the eigenfunctions of nonrelativistic hydrogen atom in the momentum representation and Klein-Gordon propagators has allowed the calculation of the Wigner function for an arbitrary bound state of the hydrogen atom. These Wigner functions for some low lying states are depicted and discussed.Comment: 8 pages (including figures

    Third-Party Effects

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    Most theories about effects of social embeddedness on trust define mechanisms that assume someone’s decision to trust is based on the reputation of the person to be trusted or on other available information. However, there is little empirical evidence about how subjects use the information that is available to them. In this chapter, we derive hypotheses about the effects of reputation and other information on trust from a range of theories and we devise an experiment that allows for testing these hypotheses simultaneously. We focus on the following mechanisms: learning, imitation, social comparison, and control. The results show that actors learn particularly from their own past experiences. Considering third-party information, imitation seems to be especially important

    Guided graded exercise self-help for chronic fatigue syndrome: Patient experiences and perceptions

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    Purpose: This study explored patient experiences of Guided graded Exercise Self-help delivered as part of a randomised controlled trial for people with chronic fatigue syndrome/myalgic encephalomyelitis, which found that Guided graded Exercise Self-help was better than specialist medical care at reducing fatigue and improving physical functioning. Methods: Semi-structured interviews were conducted with patients reporting improvement (n=9) and deteriorated (n = 10), and analysed using a thematic “constant comparison”. Results: The improved group described more facilitators to doing Guided graded Exercise Self-help, and were more likely to describe high levels of self-motivation, whilst the deteriorated group described more barriers to Guided graded Exercise Self-help (including worse exacerbation of symptoms after Guided graded Exercise Self-help, greater interference from comorbid conditions and obstacles to Guided graded Exercise Self-help in their lives), and had been ill for longer. Having the capacity to do Guided graded Exercise Self-help was important; of note, those with relatively lower levels of functioning sometimes had more time and space in their lives to support their Guided graded Exercise Self-help engagement. We identified an important ‘indeterminate phase’ early on, in which participants did not initially improve. Conclusions: Guided graded Exercise Self-help may be improved by targeting those most likely to improve, and education about the indeterminate phase
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