Clustering via kernel decomposition

Spectral clustering methods were proposed recently which rely on the eigenvalue decomposition of an affinity matrix. In this letter, the affinity matrix is created from the elements of a nonparametric density estimator and then decomposed to obtain posterior probabilities of class membership. Hyperparameters are selected using standard cross-validation methods

Epigeic spiders of the pastures of northern Wielkopolska

The fauna of epigeic spiders (Araneae) occurring on three different types of pastures in northern Wielkopolska was analysed. Studies were conducted from May 1992 to October 1993. The 18,995 specimens collected were classified as belonging to 137 species and 17 families. The family Linyphiidae proved the richest in species while Lycosidae was the most abundantly in terms of number of specimens. Zoocenological analysis of spider communities showed their differentiation testifying to differences in the sites studied. The dominants were: 1) Osowo Stare (Site 1): Pardosa palustris, 2) Sycyn Dolny (Site 2): Xerolycosa miniata, P. palustris, Xysticus kochi, 3) Brqczewo (Site 3): Erigone dentipalpis, P. palustris. Seasonal changes of dominance of the species at each site were established. A comparison of changes of the species' dominances in the years 1992 and 1993 disclosed similar values of the individual dominance coefficient at the sites in Osowo Stare and Brqczewo. This result indicates the occurrence of the process of stabilization of these biocenoses and a tendency to equilibrium in the environment. The least stable proved to be the site at Sycyn Dolny. Analysis of the seasonal dynamics of epigeic spider communities was also made by determining the mean number of species at each site in the two years of study. The highest number of species was noted in spring. It is interesting to note the appearance of species which are rare or very rare in Poland such as: Lepthyphantes insignis, Ostearius melanopygius, Enoplogriatha mordax and Enoplognatha oelandica

Keystroke dynamics in the pre-touchscreen era

Biometric authentication seeks to measure an individual’s unique physiological attributes for the purpose of identity verification. Conventionally, this task has been realized via analyses of fingerprints or signature iris patterns. However, whilst such methods effectively offer a superior security protocol compared with password-based approaches for example, their substantial infrastructure costs, and intrusive nature, make them undesirable and indeed impractical for many scenarios. An alternative approach seeks to develop similarly robust screening protocols through analysis of typing patterns, formally known as keystroke dynamics. Here, keystroke analysis methodologies can utilize multiple variables, and a range of mathematical techniques, in order to extract individuals’ typing signatures. Such variables may include measurement of the period between key presses, and/or releases, or even key-strike pressures. Statistical methods, neural networks, and fuzzy logic have often formed the basis for quantitative analysis on the data gathered, typically from conventional computer keyboards. Extension to more recent technologies such as numerical keypads and touch-screen devices is in its infancy, but obviously important as such devices grow in popularity. Here, we review the state of knowledge pertaining to authentication via conventional keyboards with a view toward indicating how this platform of knowledge can be exploited and extended into the newly emergent type-based technological contexts

Designing authentication with seniors in mind

Developers typically adopt perceived best practice, and in the case of authentication this means password security. However, given the wide range of technical solutions available and the diverse needs and limitations of older users, we suggest that the default adoption of electronic “username and password” authentication may not be 'best practice' or even good practice. This paper highlights some challenges faced by three seniors, each of whom has multiple age- related disabilities and concomitant life challenges. The result is that they cannot authenticate themselves when they need to access their devices and accounts. We conclude by suggesting a number of research directions calculated to address some of these challenges and promote inclusive design and allow for diverse user authentication

An analysis into early customer experiences of self-service checkouts:lessons for improved usability

The research aims to examine the perceptions of relative novice users of self-service checkouts (SSCOs) and if these perceptions change before, during and following use. Employing a diary approach with 31 respondents relatively unfamiliar with SSCOs, the research will document their experiences with this technology across stationary, hardware and grocery stores in two Scottish cities (Glasgow and Dundee). Findings suggest that the majority of respondents were motivated to use the technology because of time saving and convenience. However, the actual experience of using SSCOs was not always considered quicker when compared to staffed checkouts because of technical issues, lack of staff assistance and the impersonal, sometimes stressful and controlled nature of the cramped SSCO environment. Following post-use reflections, the majority of respondents’ opinions did not change from their initial perceptions and indicated that they would prefer not to use the technology in the future. Based on the findings, this study makes some practical suggestions centring on the design and usability of SSCOs, which may go some way to reducing customer dissatisfaction and frustration with the technology, especially from the perspective of new users of the technology

Linking recorded data with emotive and adaptive computing in an eHealth environment

Telecare, and particularly lifestyle monitoring, currently relies on the ability to detect and respond to changes in individual behaviour using data derived from sensors around the home. This means that a significant aspect of behaviour, that of an individuals emotional state, is not accounted for in reaching a conclusion as to the form of response required. The linked concepts of emotive and adaptive computing offer an opportunity to include information about emotional state and the paper considers how current developments in this area have the potential to be integrated within telecare and other areas of eHealth. In doing so, it looks at the development of and current state of the art of both emotive and adaptive computing, including its conceptual background, and places them into an overall eHealth context for application and development

eHealth and the Internet of Things

To respond to an ageing population, eHealth strategies offer significant opportunities in achieving a balanced and sustainable healthcare infrastructure. Advances in technology both at the sensor and device levels and in respect of information technology have opened up other possibilities and options. Of significance among these is what is increasingly referred to as the Internet of Things, the interconnection of physical devices to an information infrastructure. The paper therefore sets out to position the Internet of Things at the core of future developments in eHealt

Changing the view:towards the theory of visualisation comprehension

The core problem of the evaluation of information visualisation is that the end product of visualisation - the comprehension of the information from the data - is difficult to measure objectively. This paper outlines a description of visualisation comprehension based on two existing theories of perception: principles of perceptual organisation and the reverse hierarchy theory. The resulting account of the processes involved in visualisation comprehension enables evaluation that is not only objective, but also non-comparative, providing an absolute efficiency classification. Finally, as a sample application of this approach, an experiment studying the benefits of interactivity in 3D scatterplots is presented

Animated virtual agents to cue user attention: comparison of static and dynamic deictic cues on gaze and touch responses

This paper describes an experiment developed to study the performance of virtual agent animated cues within digital interfaces. Increasingly, agents are used in virtual environments as part of the branding process and to guide user interaction. However, the level of agent detail required to establish and enhance efficient allocation of attention remains unclear. Although complex agent motion is now possible, it is costly to implement and so should only be routinely implemented if a clear benefit can be shown. Pevious methods of assessing the effect of gaze-cueing as a solution to scene complexity have relied principally on two-dimensional static scenes and manual peripheral inputs. Two experiments were run to address the question of agent cues on human-computer interfaces. Both experiments measured the efficiency of agent cues analyzing participant responses either by gaze or by touch respectively. In the first experiment, an eye-movement recorder was used to directly assess the immediate overt allocation of attention by capturing the participant’s eyefixations following presentation of a cueing stimulus. We found that a fully animated agent could speed up user interaction with the interface. When user attention was directed using a fully animated agent cue, users responded 35% faster when compared with stepped 2-image agent cues, and 42% faster when compared with a static 1-image cue. The second experiment recorded participant responses on a touch screen using same agent cues. Analysis of touch inputs confirmed the results of gaze-experiment, where fully animated agent made shortest time response with a slight decrease on the time difference comparisons. Responses to fully animated agent were 17% and 20% faster when compared with 2-image and 1-image cue severally. These results inform techniques aimed at engaging users’ attention in complex scenes such as computer games and digital transactions within public or social interaction contexts by demonstrating the benefits of dynamic gaze and head cueing directly on the users’ eye movements and touch responses