3,123 research outputs found
Did you Pack your Keys? Smart Objects And Forgetfulness
Engineering and Physical Sciences Research Council (EPSRC) as part of the Centre for Doctoral Training in Media and Arts Technology at Queen Mary University of London
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 visitorsâ 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 systemâs 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
Designing electronic collaborative learning environments
Electronic collaborative learning environments for learning and working are in vogue. Designers design them according to their own constructivist interpretations of what collaborative learning is and what it should achieve. Educators employ them with different educational approaches and in diverse situations to achieve different ends. Students use them, sometimes very enthusiastically, but often in a perfunctory way. Finally, researchers study them andâas is usually the case when apples and oranges are comparedâfind no conclusive evidence as to whether or not they work, where they do or do not work, when they do or do not work and, most importantly, why, they do or do not work. This contribution presents an affordance framework for such collaborative learning environments; an interaction design procedure for designing, developing, and implementing them; and an educational affordance approach to the use of tasks in those environments. It also presents the results of three projects dealing with these three issues
Classification of Polarimetric SAR Data Using Dictionary Learning
End-user development (EUD) research has yielded a variety of novel environments and techniques, often accompanied by lab-based usability studies that test their effectiveness in the completion of representative real-world tasks. While lab studies play an important role in resolving frustrations and demonstrating the potential of novel tools, they are insufficient to accurately determine the acceptance of a technology in its intended context of use, which is highly dependent on the diverse and dynamic requirements of its users, as we show here. As such, usability in the lab is unlikely to represent usability in the field. To demonstrate this, we first describe the results of a think-aloud usability study of our EUD tool âJeevesâ, followed by two case studies where Jeeves was used by psychologists in their work practices. Common issues in the artificial setting were seldom encountered in the real context of use, which instead unearthed new usability issues through unanticipated user needs. We conclude with considerations for usability evaluation of EUD tools that enable development of software for other users, including planning for collaborative activities, supporting developers to evaluate their own tools, and incorporating longitudinal methods of evaluation.Postprin
Ground-state properties of the attractive one-dimensional Bose-Hubbard model
We study the ground state of the attractive one-dimensional Bose-Hubbard
model, and in particular the nature of the crossover between the weak
interaction and strong interaction regimes for finite system sizes. Indicator
properties like the gap between the ground and first excited energy levels, and
the incremental ground-state wavefunction overlaps are used to locate different
regimes. Using mean-field theory we predict that there are two distinct
crossovers connected to spontaneous symmetry breaking of the ground state. The
first crossover arises in an analysis valid for large L with finite N, where L
is the number of lattice sites and N is the total particle number. An
alternative approach valid for large N with finite L yields a second crossover.
For small system sizes we numerically investigate the model and observe that
there are signatures of both crossovers. We compare with exact results from
Bethe ansatz methods in several limiting cases to explore the validity for
these numerical and mean-field schemes. The results indicate that for finite
attractive systems there are generically three ground-state phases of the
model.Comment: 17 pages, 12 figures, Phys.Rev.B(accepted), minor changes and updated
reference
GDI as an alternative guiding interaction style for occasional users.
PolĂtica de acceso abierto tomada de: https://www.springernature.com/gp/open-research/policies/book-policiesIt is usually taken for granted that Direct Manipulation is the best interaction style for inexperienced or non-expert users; moreover, this style of interaction is generally considered the best for almost every situation and user. The recent shifts in technology that we all are currently experiencing have given rise to a great deal of new kinds of users performing specific tasks in a variety of scenarios. In this paper, we focus on users who access a system occasionally, infrequently, or in an unplanned way; i.e., users who do not want or cannot afford a learning curve. We show that for them, Direct Manipulation is not always the most suitable style of interaction. We assess the advantages of guiding this kind of users, in particular through the guided interaction frame- work known as Goal Driven Interaction. GDI can be viewed as a superset of wizards providing support far beyond a few steps through dialogs. Indeed, GDI is an interaction style with characteristics of its own. We report a complete user test that backs up previous hypotheses. The analysis of empirical data proves that GDI is more time-efficient than DM, requiring fewer moderator assistances for the users. Post-test questionnaires confirmed that participants had a strong preference for GDI
Noise effects in the quantum search algorithm from the computational complexity point of view
We analyse the resilience of the quantum search algorithm in the presence of
quantum noise modelled as trace preserving completely positive maps. We study
the influence of noise on computational complexity of the quantum search
algorithm. We show that only for small amounts of noise the quantum search
algorithm is still more efficient than any classical algorithm.Comment: 7 pages, 2 figure
Particle-hole symmetry and transport properties of the flux state in underdoped cuprates
Transport properties are studied for the flux state with the gauge flux
per plaquett, which may model the underdoped cuprates, with the emphasis
on the particle-hole and parity/chiral symmetries.This model is reduced to the
Dirac fermions in (2+1)D with a mass gap introduced by the antiferromagnetic
(AF) long range order and/or the stripe formation. Without the mass gap, the
Hall constant and the thermopower obey two-parameter scaling laws,
and show the strong temperature dependence due to the recovery of the
particle-hole symmetry at high temperature. The -dependences of and (independent of ) are in a sharp
contradiction with the experiments. (Here is the hole concentration.)
Therefore there is no signature of the particle-hole symmetry or the massless
Dirac fermions in the underdoped cuprates even above the Neel temperature
. With the mass gap introduced by the AF order, there occurs the parity
anomaly for each of the Dirac fermions. However the contributions from
different valleys and spins cancel with each other to result in no spontaneous
Hall effect even if the time-reversal symmetry is broken with .
The effects of the stripes are also studied. The diagonal and vertical
(horizontal) stripes have quite different influence on the transport
properties. The suppression of occurs at low temperature only when (i)
both the AF order and the vertical (horizontal) stripe coexist, and (ii) the
average over the in-plane direction is taken. Discussions on the recent
experiments are given from the viewpoint of these theoretical results.Comment: RevTeX, 14 pages, 11 figure
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