5,706 research outputs found
Reviewing and extending the five-user assumption: A grounded procedure for interaction evaluation
" © ACM, 2013. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in ACM Transactions on Computer-Human Interaction (TOCHI), {VOL 20, ISS 5, (November 2013)} http://doi.acm.org/10.1145/2506210 "The debate concerning how many participants represents a sufficient number for interaction testing is
well-established and long-running, with prominent contributions arguing that five users provide a good
benchmark when seeking to discover interaction problems. We argue that adoption of five users in this
context is often done with little understanding of the basis for, or implications of, the decision. We present
an analysis of relevant research to clarify the meaning of the five-user assumption and to examine the
way in which the original research that suggested it has been applied. This includes its blind adoption and
application in some studies, and complaints about its inadequacies in others. We argue that the five-user
assumption is often misunderstood, not only in the field of Human-Computer Interaction, but also in fields
such as medical device design, or in business and information applications. The analysis that we present
allows us to define a systematic approach for monitoring the sample discovery likelihood, in formative and
summative evaluations, and for gathering information in order to make critical decisions during the
interaction testing, while respecting the aim of the evaluation and allotted budget. This approach – which
we call the ‘Grounded Procedure’ – is introduced and its value argued.The MATCH programme (EPSRC Grants: EP/F063822/1 EP/G012393/1
Determination of the strange nucleon form factors
The strange contribution to the electric and magnetic form factors of the
nucleon is determined at a range of discrete values of up to
GeV. This is done by combining recent lattice QCD results for the
electromagnetic form factors of the octet baryons with experimental
determinations of those quantities. The most precise result is a small negative
value for the strange magnetic moment: . At
larger values of both the electric and magnetic form factors are
consistent with zero to within -sigma
Charge Symmetry Violation in the Electromagnetic Form Factors of the Proton
Experimental tests of QCD through its predictions for the strange-quark
content of the proton have been drastically restricted by our lack of knowledge
of the violation of charge symmetry (CSV). We find unexpectedly tiny CSV in the
proton's electromagnetic form factors by performing the first extraction of
these quantities based on an analysis of lattice QCD data. The resulting values
are an order of magnitude smaller than current bounds on proton strangeness
from parity violating electron-proton scattering experiments. This result paves
the way for a new generation of experimental measurements of the proton's
strange form factors to challenge the predictions of QCD
Cost of Fire in Highrise Building
The recent Grenfell tower fire disaster in 2017 and Hackitt Review heightened the need to address the issues of fire safety regulations. However, increasing pressure to reduce building costs and to complete construction projects on time remains a major challenge. This study examines the cost of fire in high rise building projects and the implications for the professional development of quantity surveyors (QS). The methodology adopted is a case study approach drawing on the recent experience of the Grenfell tower fire disaster of 2017, an analysis of data collected on fire provision in high rise buildings using the BCIS database and a review of the RICS New Rules of Measurement (NRM). Given the significant cost of fire in high rise buildings, there is a need for adequate provision in fire protection by investing in costs in anticipation of fire during cost planning stages to significantly reduce the costs associated with the consequence and responses after a fire incident estimated to be extremely high in the case of Grenfell. The QS need to move away from ad hoc approaches adopted in pricing items specific to fire protection as part of a team of professionals and developing the required competencies will significantly reduce the risk of not pricing adequately for fire provision in the cost plan
Three-dimensional arrangement of elastic fibers in the human corneal stroma
This is the final version of the article. Available from the publisher via the DOI in this record.The cornea is the main refracting lens in the eye. As part of the outer tunic it has to be resilient, a property conferred by the organisation of the constituent collagen. It also has to be sufficiently elastic to regain its exact shape when deformed, in order not to distort the retinal image. The basis of this elasticity is not fully understood. The purpose of this study was to characterise in three dimensions the arrangement and distribution of elastic fibers in the human corneal stroma, using serial block face scanning electron microscopy. We have demonstrated that there exists a complex network of elastic fibers that appear to originate in the sclera or limbus. These appear as elastic sheets in the limbus and peripheral cornea immediately above the trabecular meshwork which itself appears to extend above Descemet's membrane in the peripheral stroma. From these sheets, elastic fibers extend into the cornea; moving centrally they bifurcate and trifurcate into narrower fibers and are concentrated in the posterior stroma immediately above Descemet's membrane. We contend that elastic sheets will play an important role in the biomechanical deformation and recovery of the peripheral cornea. The network may also have practical implications for understanding the structural basis behind a number of corneal surgeries.We would like to thank Dr Anthony Hayes and Mr Derek Scarborough
for help with the histology presented in this study and Dr
Sally Hayes for useful discussions concerning data interpretation.
This work was funded by a Programme Grant (503626) from the
Medical Research Council (to KMM) and an MRC studentship (to
TW). We thank the CTC Eye Bank at Bristol, UK and the HDBR at
Newcastle, UK, for supply of human corneas. The authors have no
conflicts of interest to declare
How citation boosts promote scientific paradigm shifts and Nobel Prizes
Nobel Prizes are commonly seen to be among the most prestigious achievements
of our times. Based on mining several million citations, we quantitatively
analyze the processes driving paradigm shifts in science. We find that
groundbreaking discoveries of Nobel Prize Laureates and other famous scientists
are not only acknowledged by many citations of their landmark papers.
Surprisingly, they also boost the citation rates of their previous
publications. Given that innovations must outcompete the rich-gets-richer
effect for scientific citations, it turns out that they can make their way only
through citation cascades. A quantitative analysis reveals how and why they
happen. Science appears to behave like a self-organized critical system, in
which citation cascades of all sizes occur, from continuous scientific progress
all the way up to scientific revolutions, which change the way we see our
world. Measuring the "boosting effect" of landmark papers, our analysis reveals
how new ideas and new players can make their way and finally triumph in a world
dominated by established paradigms. The underlying "boost factor" is also
useful to discover scientific breakthroughs and talents much earlier than
through classical citation analysis, which by now has become a widespread
method to measure scientific excellence, influencing scientific careers and the
distribution of research funds. Our findings reveal patterns of collective
social behavior, which are also interesting from an attention economics
perspective. Understanding the origin of scientific authority may therefore
ultimately help to explain, how social influence comes about and why the value
of goods depends so strongly on the attention they attract.Comment: 6 pages, 6 figure
Casting Light on Dark Matter
The prospects for detecting a candidate supersymmetric dark matter particle
at the LHC are reviewed, and compared with the prospects for direct and
indirect searches for astrophysical dark matter. The discussion is based on a
frequentist analysis of the preferred regions of the Minimal supersymmetric
extension of the Standard Model with universal soft supersymmetry breaking (the
CMSSM). LHC searches may have good chances to observe supersymmetry in the near
future - and so may direct searches for astrophysical dark matter particles,
whereas indirect searches may require greater sensitivity, at least within the
CMSSM.Comment: 16 pages, 13 figures, contribution to the proceedings of the LEAP
2011 Conferenc
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