190 research outputs found
User-centred design of flexible hypermedia for a mobile guide: Reflections on the hyperaudio experience
A user-centred design approach involves end-users from the very beginning. Considering users at the early stages compels designers to think in terms of utility and usability and helps develop the system on what is actually needed. This paper discusses the case of HyperAudio, a context-sensitive adaptive and mobile guide to museums developed in the late 90s. User requirements were collected via a survey to understand visitors’ profiles and visit styles in Natural Science museums. The knowledge acquired supported the specification of system requirements, helping defining user model, data structure and adaptive behaviour of the system. User requirements guided the design decisions on what could be implemented by using simple adaptable triggers and what instead needed more sophisticated adaptive techniques, a fundamental choice when all the computation must be done on a PDA. Graphical and interactive environments for developing and testing complex adaptive systems are discussed as a further
step towards an iterative design that considers the user interaction a central point. The paper discusses
how such an environment allows designers and developers to experiment with different system’s behaviours and to widely test it under realistic conditions by simulation of the actual context evolving over time. The understanding gained in HyperAudio is then considered in the perspective of the
developments that followed that first experience: our findings seem still valid despite the passed time
Benevolent characteristics promote cooperative behaviour among humans
Cooperation is fundamental to the evolution of human society. We regularly
observe cooperative behaviour in everyday life and in controlled experiments
with anonymous people, even though standard economic models predict that they
should deviate from the collective interest and act so as to maximise their own
individual payoff. However, there is typically heterogeneity across subjects:
some may cooperate, while others may not. Since individual factors promoting
cooperation could be used by institutions to indirectly prime cooperation, this
heterogeneity raises the important question of who these cooperators are. We
have conducted a series of experiments to study whether benevolence, defined as
a unilateral act of paying a cost to increase the welfare of someone else
beyond one's own, is related to cooperation in a subsequent one-shot anonymous
Prisoner's dilemma. Contrary to the predictions of the widely used inequity
aversion models, we find that benevolence does exist and a large majority of
people behave this way. We also find benevolence to be correlated with
cooperative behaviour. Finally, we show a causal link between benevolence and
cooperation: priming people to think positively about benevolent behaviour
makes them significantly more cooperative than priming them to think
malevolently. Thus benevolent people exist and cooperate more
Adaptive Web-Based Educational Hypermedia
This chapter describes recent and ongoing research to automatically personalize a learning experience through adaptive educational hypermedia. The Web had made it possible to give a very large audience access to the same learning material. Rather than offering several versions of learning material about a certain subject, for different types of leaners, adaptive educational hypermedia offers personalized learning material without the need to know a detailed classification of users before starting the learning process. We describe different approaches to making a learning experience personalized, all using adaptive hypermedia technology. We include research on authoring for adaptive learning material (the AIMS and MOT projects) and research on modeling adaptive educational applications (the LAOS project). We also cover some of our ongoing work on the AHA! system, which has been used mostly for educational hypermedia but has the potential to be used in very different application areas as wel
Evidence for B- -> Ds+ K- l- nubar and search for B- -> Ds*+ K- l- nubar
We report measurements of the decays B- -> Ds(*)+ K- l- nubar in a data
sample containing 657x10^6 BBbar pairs collected with the Belle detector at the
KEKB asymmetric-energy e+e- collider. We observe a signal with a significance
of 6 sigma for the combined Ds and Ds* modes and find the first evidence of the
B- -> Ds+ K- l- nubar decay with a significance of 3.4 sigma. We measure the
following branching fractions: BF(B- -> Ds+ K- l nubar) = (0.30 +/- 0.09(stat)
+0.11 -0.08(syst)) x 10^-3 and BF(B- -> Ds*+ K- l- nubar) = (0.59 +/-
0.12(stat) +/- 0.15(syst)) x 10^-3 and set an upper limit BF(B- -> Ds*+ K- l-
nubar) < 0.56 x 10^-3 at the 90% confidence level. We also present the first
measurement of the Ds+K- invariant mass distribution in these decays, which is
dominated by a prominent peak around 2.6 GeV/c^2.Comment: Submitted to Phys. Rev.
Searching for gravitational waves from known pulsars
We present upper limits on the amplitude of gravitational waves from 28
isolated pulsars using data from the second science run of LIGO. The results
are also expressed as a constraint on the pulsars' equatorial ellipticities. We
discuss a new way of presenting such ellipticity upper limits that takes
account of the uncertainties of the pulsar moment of inertia. We also extend
our previous method to search for known pulsars in binary systems, of which
there are about 80 in the sensitive frequency range of LIGO and GEO 600.Comment: Accepted by CQG for the proceeding of GWDAW9, 7 pages, 2 figure
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