BackgroundFalls in the elderly is nowadays a major concern because of their consequences on elderly general health and moral states. Moreover, the aging of the population and the increasing life expectancy make the prediction of falls more and more important. The analysis presented in this article makes a first step in this direction providing a way to analyze gait and classify hospitalized elderly fallers and non-faller. This tool, based on an accelerometer network and signal processing, gives objective informations about the gait and does not need any special gait laboratory as optical analysis do. The tool is also simple to use by a non expert and can therefore be widely used on a large set of patients.MethodA population of 20 hospitalized elderlies was asked to execute several classical clinical tests evaluating their risk of falling. They were also asked if they experienced any fall in the last 12 months. The accelerations of the limbs were recorded during the clinical tests with an accelerometer network distributed on the body. A total of 67 features were extracted from the accelerometric signal recorded during a simple 25 m walking test at comfort speed. A feature selection algorithm was used to select those able to classify subjects at risk and not at risk for several classification algorithms types.ResultsThe results showed that several classification algorithms were able to discriminate people from the two groups of interest: fallers and non-fallers hospitalized elderlies. The classification performances of the used algorithms were compared. Moreover a subset of the 67 features was considered to be significantly different between the two groups using a t-test.ConclusionsThis study gives a method to classify a population of hospitalized elderlies in two groups: at risk of falling or not at risk based on accelerometric data. This is a first step to design a risk of falling assessment system that could be used to provide the right treatment as soon as possible before the fall and its consequences. This tool could also be used to evaluate the risk several times during the revalidation procedure.

The majority of organisations are globalising their software development activities by following the ideas of global software development (GSD). The motivation behind the adoption of GSD phenomena are the list of benefits gained by the software industry. However, there are different challenges face by the GSD organisations, particularly the issues related to software process improvement (SPI). The aim of this study is the identification and classification into categories of the success factors that can impact SPI initiatives taken in GSD organisations. The systematic literature review (SLR) method has been used to extract the success factors from the literature. SLR phases, 'planning, conducting, and reporting the review' have been followed to perform this study. Totally, 15 success factors were identified and classified into the six main categories. The authors have also reported the critical success factors of SPI, i.e. management commitment, staff involvement, roles and responsibilities, communication, and resources allocation. This article also reported the similarities and differences between the success factors classified on the bases of client-vendor organisation and size of the organisation. The identified factors can contribute towards the implementation of SPI programme in both client and vendor GSD organisations because these factors represent key areas of process improvement.

Abstract. Multi-fidelity prototyping combines within a single user interface prototype several elements whose representations are reproduced with different levels of fidelity with respect to the final user interface: no fidelity at all, low fidelity, medium fidelity, and high fidelity. In order to effectively and efficiently support multi-fidelity, an original set of techniques is defined and discussed: multiple representation manipulation by sketching and gesture recognition, smooth transition between any representation at any time, prototype reusability, multi-platform support, and multiple user interface prototyping facilities. The full implementation of these techniques in prototyping software provides designers and developers with a unique environment for exploring multiple designs with unprecedented support for quickly designing interfaces from scratch or from previously existing design templates. An experimental study reveals that the multiple representation manipulation together with smooth transition represents a valuable advantage for naturally designing user interfaces. The prototyping software supports several aspects involved in the user interface development life cycle and is convenient for non-WIMP user interfaces.

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We report an experimental study that aims at investigating the influence of spatial layout on visual search efficiency and comfort. 4 layouts were used for displaying 120 scenes comprising 30 realistic colour photos each: random, elliptic, radial and matrix-like. Scenes (30 per structure) were presented to 5 participants who had to select a previewed photo in each scene using the mouse. Eye-tracking data indicate that elliptic layouts provided better visual comfort than any of the other layouts (shortest scan paths), and proved to be more efficient than matrix layouts (shorter search times). These results are statistically significant (paired t-tests).

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The term ecological validity refers to the study of the measurable correspondence between experimental design and ecological setting (i.e., representative users performing real tasks in their natural environment). Therefore, it is important to anyone intending to generalize the conclusions from the particular circumstances of an experiment to wider ecological situations. However, there is no operational definition that enables to objectively quantify the ecological validity of an experimental design. The ECOVAL framework offers a formal starting point to bridge this gap by helping to both define and increase the ecological validity in usability testing. A methodology, a tool and guidelines to increase ecological validity are presented in an industrial case study. The return on investment of increasing ecological validity is examined in terms of user efficiencies and usability practice. Finally, recommendations to increase ecological validity are introduced, contributions discussed, and outlines for future work presented.

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