12,326 research outputs found

    Usability evaluation of digital libraries: a tutorial

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    This one-day tutorial is an introduction to usability evaluation for Digital Libraries. In particular, we will introduce Claims Analysis. This approach focuses on the designers’ motivations and reasons for making particular design decisions and examines the effect on the user’s interaction with the system. The general approach, as presented by Carroll and Rosson(1992), has been tailored specifically to the design of digital libraries. Digital libraries are notoriously difficult to design well in terms of their eventual usability. In this tutorial, we will present an overview of usability issues and techniques for digital libraries, and a more detailed account of claims analysis, including two supporting techniques – simple cognitive analysis based on Norman’s ‘action cycle’ and Scenarios and personas. Through a graduated series of worked examples, participants will get hands-on experience of applying this approach to developing more usable digital libraries. This tutorial assumes no prior knowledge of usability evaluation, and is aimed at all those involved in the development and deployment of digital libraries

    Trispectrum versus Bispectrum in Single-Field Inflation

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    In the standard slow-roll inflationary cosmology, quantum fluctuations in a single field, the inflaton, generate approximately Gaussian primordial density perturbations. At present, the bispectrum and trispectrum of the density perturbations have not been observed and the probability distribution for these perturbations is consistent with Gaussianity. However, Planck satellite data will bring a new level of precision to bear on this issue, and it is possible that evidence for non-Gaussian effects in the primordial distribution will be discovered. One possibility is that a trispectrum will be observed without evidence for a non-zero bispectrum. It is not difficult for this to occur in inflationary models where quantum fluctuations in a field other than the inflaton contribute to the density perturbations. A natural question to ask is whether such an observation would rule out the standard scenarios. We explore this issue and find that it is possible to construct single-field models in which inflaton-generated primordial density perturbations have an observable trispectrum, but a bispectrum that is too small to be observed by the Planck satellite. However, an awkward fine tuning seems to be unavoidable.Comment: 15 pages, 3 figures; journal versio

    Proton structure corrections to hyperfine splitting in muonic hydrogen

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    We present the derivation of the formulas for the proton structure-dependent terms in the hyperfine splitting of muonic hydrogen. We use compatible conventions throughout the calculations to derive a consistent set of formulas that reconcile differences between our results and some specific terms in earlier work. Convention conversion corrections are explicitly presented, which reduce the calculated hyperfine splitting by about 46 ppm. We also note that using only modern fits to the proton elastic form factors gives a smaller than historical spread of Zemach radii and leads to a reduced uncertainty in the hyperfine splitting. Additionally, hyperfine splittings have an impact on the muonic hydrogen Lamb shift/proton radius measurement, however the correction we advocate has a small effect there.Comment: 6 pages, 3 figure

    The challenge of mainstreaming ICT design for all.

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    The education and training of ICT students and professionals with respect to Design for All is a vital part in the process of achieving eInclusion throughout Europe. This paper outlines the latest activity on the development of a curriculum in Design for All in ICT in higher education and professional development, and discusses some of the challenges of mainstreaming ICT Design for All. Concepts have been devised to introduce Design for All at bachelor-level of mainstream ICT education, to implement a masters degree in Design for All, and to provide training for professionals in ICT industry

    AI Solutions for MDS: Artificial Intelligence Techniques for Misuse Detection and Localisation in Telecommunication Environments

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    This report considers the application of Articial Intelligence (AI) techniques to the problem of misuse detection and misuse localisation within telecommunications environments. A broad survey of techniques is provided, that covers inter alia rule based systems, model-based systems, case based reasoning, pattern matching, clustering and feature extraction, articial neural networks, genetic algorithms, arti cial immune systems, agent based systems, data mining and a variety of hybrid approaches. The report then considers the central issue of event correlation, that is at the heart of many misuse detection and localisation systems. The notion of being able to infer misuse by the correlation of individual temporally distributed events within a multiple data stream environment is explored, and a range of techniques, covering model based approaches, `programmed' AI and machine learning paradigms. It is found that, in general, correlation is best achieved via rule based approaches, but that these suffer from a number of drawbacks, such as the difculty of developing and maintaining an appropriate knowledge base, and the lack of ability to generalise from known misuses to new unseen misuses. Two distinct approaches are evident. One attempts to encode knowledge of known misuses, typically within rules, and use this to screen events. This approach cannot generally detect misuses for which it has not been programmed, i.e. it is prone to issuing false negatives. The other attempts to `learn' the features of event patterns that constitute normal behaviour, and, by observing patterns that do not match expected behaviour, detect when a misuse has occurred. This approach is prone to issuing false positives, i.e. inferring misuse from innocent patterns of behaviour that the system was not trained to recognise. Contemporary approaches are seen to favour hybridisation, often combining detection or localisation mechanisms for both abnormal and normal behaviour, the former to capture known cases of misuse, the latter to capture unknown cases. In some systems, these mechanisms even work together to update each other to increase detection rates and lower false positive rates. It is concluded that hybridisation offers the most promising future direction, but that a rule or state based component is likely to remain, being the most natural approach to the correlation of complex events. The challenge, then, is to mitigate the weaknesses of canonical programmed systems such that learning, generalisation and adaptation are more readily facilitated

    Structural Relationship between Negative Thermal Expansion and Quartic Anharmonicity of Cubic ScF_3

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    Cubic scandium trifluoride (ScF_3) has a large negative thermal expansion over a wide range of temperatures. Inelastic neutron scattering experiments were performed to study the temperature dependence of the lattice dynamics of ScF3 from 7 to 750 K. The measured phonon densities of states show a large anharmonic contribution with a thermal stiffening of modes around 25 meV. Phonon calculations with first-principles methods identified the individual modes in the densities of states, and frozen phonon calculations showed that some of the modes with motions of F atoms transverse to their bond direction behave as quantum quartic oscillators. The quartic potential originates from harmonic interatomic forces in the DO_9 structure of ScF_3, and accounts for phonon stiffening with the temperature and a significant part of the negative thermal expansion

    Multilevel Converter-Based Dual-Frequency Induction Heating Power Supply

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    Most existing power supplies for induction heating equipment produce voltage at a single (adjustable) frequency. Recently, however, induction heating power supplies that produce voltage at two (adjustable) frequencies have been researched and even commercialized. Dual-frequency power supplies are a significant development for heat-treating workpieces with uneven geometries, such as gears, since different portions of such workpieces are heated dissimilarly at a single frequency and so require a two step process using a single-frequency power supply. On the other hand, a dual-frequency power supply can achieve the desired result for such workpieces in a one step process. However, the existing approaches to dual-frequency voltage generation could be improved to achieve higher efficiency, improved control, reduced electromagnetic interference and greater reliability. This paper proposes the use of multilevel converters for providing induction heating power at two frequencies simultaneously. It also describes how the stepping angles for the desired output from this converter were determined. Furthermore, experimental results are presented as a verification of the analysis

    Gambling or Skill: Taxation Issues Surrounding the Daily Fantasy Sports Industry

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    With a waxing interest in sporting events, participants are increasingly supplementing passive viewing with a more active role. Fantasy sports leagues have burgeoned as a result, with corresponding increases in live game attendance and media consumption across platforms. Fantasy bettors seek financial gain through the ability of athletes and the likelihood of their team performing well in a sporting event. A major legislative concern within this industry is whether these activities are considered gambling, with its related stigma, or otherwise just a type of sporting activity. More importantly, gambling has a long history as a major source of tax revenue within its lineage. This paper examines these current public policy and taxation issues that will shape the future landscape of fantasy sports. Various legislation has defined type and scope of betting that have been gradually modified to permit a larger role for individual states to develop policies. A majority of states have adopted tests that apply the degree of chance versus skill in a contest. As of 2020, sports betting has been declared legal and is presently providing tax revenue in 23 states plus Washington, D.C. Higher levels of chance are generally deemed an illegal activity, using the 10th Amendment to the U.S. Constitution as a basis. Recent IRS opinions (July 2020) find that daily fantasy sports operators are liable for two federal excise taxes and must identify themselves by registering as a business accepting wagers. Lower gaming taxes are associated with a proliferation of legal sports betting. For this paper each of the following three properties must be present to be considered gambling: consideration, prize, and chance. States have authority in defining gambling activities, with Congress regulating commerce among states. Substantial opportunity exists in taxing online betting as a source of revenue or placing excise taxes on gambling as a method to control consumer 3 behavior. To the extent that federal and state governments continue debating legalized betting activities and the related taxes generated, consumer protection must focus on continued legitimacy of the environment and address addiction risk as a basis for further growth

    Proton structure corrections to electronic and muonic hydrogen hyperfine splitting

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    We present a precise determination of the polarizability and other proton structure dependent contributions to the hydrogen hyperfine splitting, based heavily on the most recent published data on proton spin dependent structure functions from the EG1 experiment at the Jefferson Laboratory. As a result, the total calculated hyperfine splitting now has a standard deviation slightly under 1 part-per-million, and is about 1 standard deviation away from the measured value. We also present results for muonic hydrogen hyperfine splitting, taking care to ensure the compatibility of the recoil and polarizability terms.Comment: 9 pages, 1 figur
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