12,326 research outputs found
Usability evaluation of digital libraries: a tutorial
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
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
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.
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
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
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
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
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
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
- …