50,855 research outputs found
Investigating the success factors of expert users to inform device development
Objective: Expert user testing is a well recognised tool within user experience and human computer interaction design. Within the domain of assistive technology device design, however, this technique seems to be little used. It is suggested that studying the success factors of expert assistive technology device users may provide a valuable source of data to inform development of assistive technology devices. This paper presents an example of this technique, within the context of a number of studies carried out by the authors, using the example of preliminary data from a study informing the development of an innovative Augmentative and Alternative Communication (AAC) device.
Main Content: The paper presents a qualitative study whose objective was to influence the design and further development of an innovative voice-input voice-output communication aid (Vivoca) which has previously reached proof-of-concept stage. The Vivoca device is designed for people with dysarthria and this dictates a number of specific constraints and considerations. In order to understand how Vivoca could be designed to be used successfully by people with dysarthria, this study aimed to identify the factors associated with expert users' successful use of current AAC devices. In order to allow comparison, the study included users with some understandable speech and also those with no understandable speech. The study procedure was designed to provide a profile of participants' communication methods and to identify the factors that participants felt made their communication successful.
Results: Preliminary results from the study (currently underway) are presented, including a qualitative analysis of interview data, and data profiling participants' communication methods and context. Initial data has highlighted the very specific requirements for a communication aid design for people with some understandable speech.
Conclusion: Study of expert users may provide an effective tool to help inform assistive technology device development
The Superbubble Size Distribution in the Interstellar Medium of Galaxies
We use the standard, adiabatic shell evolution to predict the size
distribution N(R) for populations of OB superbubbles in a uniform ISM. We
derive N(R) for simple cases of superbubble creation rate and mechanical
luminosity function (MLF). For R < the characteristic radius R_e, N(R) is
dominated by stalled objects, while for R>R_e it is dominated by growing
objects. We also briefly investigate N(R) resulting from momentum-conserving
shell evolution. We predict a peak in N(R) corresponding to individual SNRs. To
estimate the MLF, we also examine evolutionary effects on the HII region
luminosity function (HII LF), finding that for nebular luminosity fading as a
power law in time, there is a minimum observed slope for the HII LFs.
Comparison with the largely complete HI hole catalog for the SMC shows
surprising agreement in the predicted and observed slope of N(R), suggesting
that no other fundamental process is needed to explain the size distribution of
shells in the SMC. Further comparison with largely incomplete HI data for M31,
M33, and Holmberg II is also encouraging. We present expressions for the ISM
porosity parameters, and estimate that they are substantially <1 for all of the
galaxies except Holmberg II. Most of these galaxies therefore may not be
strongly dominated by a hot interstellar component. However, porosity results
for the Galaxy remain inconclusive.Comment: 25 pages, MN latex, 4 figures. MNRAS accepted. Complete abstract and
preprint also available at http://ast.cam.ac.uk/~oey/oeypubs.htm
Galactic porosity and a star formation threshold for the escape of ionising radiation from galaxies
The spatial distribution of star formation within galaxies strongly affects
the resulting feedback processes. Previous work has considered the case of a
single, concentrated nuclear starburst, and also that of distributed single
supernovae (SNe). Here, we consider ISM structuring by SNe originating in
spatially distributed clusters having a cluster membership spectrum given by
the observed HII region luminosity function. We show that in this case, the
volume of HI cleared per SN is considerably greater than in either of the two
cases considered hitherto.
We derive a simple relationship between the ``porosity'' of the ISM and the
star formation rate (SFR), and deduce a critical SFR_crit, at which the ISM
porosity is unity. This critical value describes the case in which the SN
mechanical energy output over a timescale t_e is comparable with the ISM
``thermal'' energy contained in random motions; t_e is the duration of SN
mechanical input per superbubble. This condition also defines a critical gas
consumption timescale t_exh, which for a Salpeter IMF and random velocities of
\simeq 10 km s-1 is roughly 10e10 years.
We draw a link between porosity and the escape of ionising radiation from
galaxies, arguing that high escape fractions are expected if SFR >~ SFR_crit.
The Lyman Break Galaxies, which are presumably subject to infall on a timescale
< t_exh, meet this criterion, as is consistent with the significant leakage of
ionising photons inferred in these systems. We suggest the utility of this
simple parameterisation of escape fraction in terms of SFR for semi-empirical
models of galaxy formation and evolution and for modeling mechanical and
chemical feedback effects.Comment: Accepted to MNRAS. 11 pages, 1 figure; uses mn2e.cls (included
Ageing of Natural Rubber under Stress
We report a dynamical-mechanical study of stress relaxation at small
deformation in a natural (polyisoprene) rubber well above its glass transition
temperature Tg. We find that an almost complete relaxation of stress takes
place over very long periods of time, even though the elastic network integrity
is fully retained. The relaxation rate and the long-time equilibrium modulus
are sensitive functions of temperature which do not follow time-temperature
superposition. Many characteristic features of non-ergodic ageing response are
apparent at both short and very long times. We interpret the observed behaviour
in terms of the properties of rubber crosslinks, capable of isomerisation under
stress, and relate the results to recent models of soft glassy rheology.Comment: Latex 2e (EPJ style), 5 EPS figure
The structural contradictions and constraints on corporate social responsibility: Challenges for corporate social irresponsibility
Purpose - This chapter engages critically with the ideas of corporate social responsibility (CSR) and irresponsibility (CSI) in order to examine their utility for the purposes of realizing more socially just and environmentally sustainable social and economic practices. Methodology/approach - The chapter develops Marx's understanding of the twin pressures of class struggle and inter-capitalist competition in setting the limits of agency for corporate actors. It is thus theoretical and discursive in nature. Findings - The findings of the chapter suggest that the scope for corporate agency in relation to responsibility/irresponsibility is severely limited by inter-capitalist competition and capitalist social relations. It therefore argues that those interested in social justice and environmental sustainability should focus on these structural pressures rather than theorizing corporate agency. Social implications - The research suggests that the focus of academic and government attention should be on resolving the contradictions and exploitative social relations inherent in capitalism. Without this emphasis activism, corporate agency and government action will not eradicate the types of problem that advocates of CSR/CSI are concerned about. Originality/value of paper - The value of the paper is that it contests and engages critically with the utility of the notion of CSR and the emergent concept of CSI. It asks proponents of these concepts to think seriously about the structural pressures and constraints within which business and policy makers act. Copyrightr © 2012 by Emerald Group Publishing Limited
3D printing and high tibial osteotomy
High tibial osteotomy (HTO) is a relatively conservative surgical option in the management of medial knee pain. Thus far, the outcomes have been variable, and apparently worse than the arthroplasty alternatives when judged using conventional metrics, owing in large part to uncer - tainty around the extent of the correction planned and achieved. This review paper introduces the concept of detailed 3D planning of the procedure, and describes the 3D printing technology that enables the plan to be performed. The different ways that the osteotomy can be undertaken, and the varying guide designs that enable accurate regis - tration are discussed and described. The system accuracy is reported. In keeping with other assistive technologies, 3D printing enables the surgeon to achieve a preoperative plan with a degree of accuracy that is not possible using conventional instruments. With the advent of low dose CT, it has been possible to confirm that the procedure has been under - taken accurately too. HTO is the ‘ultimate’ personal intervention: the amount of correction needed for optimal offloading is not yet com - pletely understood. For the athletic person with early medial joint line over - load who still runs and enjoys life, HTO using 3D printing is an attractive option. The clinical effectiveness remains unproven
Evolutionary breeding of healthy wheat: from plot to farm
Genetically diverse Composite Cross Populations (CCPs) may be useful in environmentally variable low-input systems as an alternative to pure line varieties. They are formed by hybridising lines with diverse evolutionary origins, bulking the F1 progeny, and allowing natural selection of the progeny in successive crop environments. CCPs derived from 10 high yielding parents (YCCPs), 12 high quality parents (QCCPs), or all 22 parents (YQCCPs), were grown at four sites (2 organic, 2 conventional) in the UK; they are currently (2006) in F5. The YCCPs out yielded the QCCPs, which had better quality characteristics. Although the CCPs performed within the range of the parents, the values obtained were often better than the mean of the parents. Some population samples are now being grown on farms and other sites in England, France, Germany and Hungary
Statistical Confirmation of a Stellar Upper Mass Limit
We derive the expectation value for the maximum stellar mass (m_max) in an
ensemble of N stars, as a function of the IMF upper-mass cutoff (m_up) and N.
We statistically demonstrate that the upper IMF of the local massive star
census observed thus far in the Milky Way and Magellanic Clouds clearly
exhibits a universal upper mass cutoff around 120 - 200 M_sun for a Salpeter
IMF, although the result is more ambiguous for a steeper IMF.Comment: PDF, 5 pages, 4 figures. Accepted to the Astrophysical Journal
Letter
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