Tactons: structured tactile messages for non-visual information display

Tactile displays are now becoming available in a form that can be easily used in a user interface. This paper describes a new form of tactile output. Tactons, or tactile icons, are structured, abstract messages that can be used to communicate messages non-visually. A range of different parameters can be used for Tacton construction including: frequency, amplitude and duration of a tactile pulse, plus other parameters such as rhythm and location. Tactons have the potential to improve interaction in a range of different areas, particularly where the visual display is overloaded, limited in size or not available, such as interfaces for blind people or in mobile and wearable devices. This paper describes Tactons, the parameters used to construct them and some possible ways to design them. Examples of where Tactons might prove useful in user interfaces are given

Drawing by ear: interpreting sonified line graphs

The research presented here describes a pilot study into the interpretation of sonified line graphs containing two data series. The experiment aimed to discover the level of accuracy with which sighted people were able to draw sketches of the graphs after listening to them. In addition, it aimed to identify any differences in performance when the graphs were presented using different combinations of instruments?either with piano representing both data series (same-instruments condition), or with piano representing one data series and trumpet representing the other (different-instruments condition). The drawings were evaluated by calculating the percentage of key features present. The results showed that accuracy was high (over 80% on average) in both conditions, but found no significant differences between the two. There were indications of some differences between the two conditions, but a larger study is necessary to discover whether these are significant. The results indicate that graph sonification systems should allow users to choose between these two presentation modes, depending on their preference and current task. The study showed that sonified graphs containing two data series can be interpreted, and drawn, by sighted people, and that evaluation with blind users (our target users) would be worthwhile

Design guidelines for audio presentation of graphs and tables

Audio can be used to make visualisations accessible to blind and visually impaired people. The MultiVis Project has carried out research into suitable methods for presenting graphs and tables to blind people through the use of both speech and non-speech audio. This paper presents guidelines extracted from this research. These guidelines will enable designers to implement visualisation systems for blind and visually impaired users, and will provide a framework for researchers wishing to investigate the audio presentation of more complex visualisations

Multidimensional tactons for non-visual information presentation in mobile devices

Tactons are structured vibrotactile messages which can be used for non-visual information presentation when visual displays are limited, unavailable or inappropriate, such as in mobile phones and other mobile devices. Little is yet known about how to design them effectively. Previous studies have investigated the perception of Tactons which encode two dimensions of information using two different vibrotactile parameters (rhythm and roughness) and found recognition rates of around 70. When more dimensions of information are required it may be necessary to extend the parameter-space of these Tactons. Therefore this study investigates recognition rates for Tactons which encode a third dimension of information using spatial location. The results show that identification rate for three-parameter Tactons is just 48, but that this can be increased to 81 by reducing the number of values of one of the parameters. These results will aid designers to select suitable Tactons for use when designing mobile displays

'Taking it to heart': girls and the meanings of violence

No abstract available

Researching girls and violence: facing the dilemmas of fieldwork

This paper explores key methodological and analytical issues encountered in an exploratory study of teenage girls' views and experiences of violence, carried out in Scotland. Researching the ways in which girls conceptualize, experience and use violence raises a number of dilemmas due in part to the sensitive nature of the research topic, and the age and gender of those taking part. Drawing on feminist debates about objectivity, the role of the researcher, power relationships in the production of knowledge, and representation, this article highlights the difficulties of adapting such principles to the day-to-day practicalities of conducting empirical research on girls and violence. It shows how the research itself has been enhanced by having to engage with and work through this complexity

A first investigation into the effectiveness of Tactons

This paper reports two experiments relating to the design of Tactons (or tactile icons). The first experiment investigated perception of vibro-tactile "roughness" (created using amplitude modulated sinusoids), and the results indicated that roughness could be used as a parameter for constructing Tactons. The second experiment is the first full evaluation of Tactons, and uses three values of roughness identified in the first experiment, along with three rhythms to create a set of Tactons. The results of this experiment showed that Tactons could be a successful means of communicating information in user interfaces, with an overall recognition rate of 71%, and recognition rates of 93% for rhythm and 80% for roughness

Dynamic instability in resonant tunneling

We show that an instability may be present in resonant tunneling through a quantum well in one, two and three dimensions, when the resonance lies near the emitter Fermi level. A simple semiclassical model which simulates the resonance and the projected density of states by a nonlinear conductor, the Coulomb barrier by a capacitance, and the time evolution by an iterated map, is used. The model reproduces the observed hysteresis in such devices, and exhibits a series of bifurcations leading to fast chaotic current fluctuations.Comment: 7 pages, 2 figure

Kinetics of acute hepatitis B virus infection in humans

Using patient data from a unique single source outbreak of hepatitis B virus (HBV) infection, we have characterized the kinetics of acute HBV infection by monitoring viral turnover in the serum during the late incubation and clinical phases of the disease in humans. HBV replicates rapidly with minimally estimated doubling times ranging between 2.2 and 5.8 d (mean 3.7 ± 1.5 d). After a peak viral load in serum of nearly 1010 HBV DNA copies/ml is attained, clearance of HBV DNA follows a two or three phase decay pattern with an initial rapid decline characterized by mean half-life (t1/2) of 3.7 ± 1.2 d, similar to the t1/2 observed in the noncytolytic clearance of covalently closed circular DNA for other hepadnaviruses. The final phase of virion clearance occurs at a variable rate (t1/2 of 4.8 to 284 d) and may relate to the rate of loss of infected hepatocytes. Free virus has a mean t1/2 of at most 1.2 ± 0.6 d. We estimate a peak HBV production rate of at least 1013 virions/day and a maximum production rate of an infected hepatocyte of 200–1,000 virions/day, on average. At this peak rate of virion production we estimate that every possible single and most double mutations would be created each day

So many genes, so little time: A practical approach to divergence-time estimation in the genomic era

Phylogenomic datasets have been successfully used to address questions involving evolutionary relationships, patterns of genome structure, signatures of selection, and gene and genome duplications. However, despite the recent explosion in genomic and transcriptomic data, the utility of these data sources for efficient divergence-time inference remains unexamined. Phylogenomic datasets pose two distinct problems for divergence-time estimation: (i) the volume of data makes inference of the entire dataset intractable, and (ii) the extent of underlying topological and rate heterogeneity across genes makes model mis-specification a real concern. “Gene shopping”, wherein a phylogenomic dataset is winnowed to a set of genes with desirable properties, represents an alternative approach that holds promise in alleviating these issues. We implemented an approach for phylogenomic datasets (available in SortaDate) that filters genes by three criteria: (i) clock-likeness, (ii) reasonable tree length (i.e., discernible information content), and (iii) least topological conflict with a focal species tree (presumed to have already been inferred). Such a winnowing procedure ensures that errors associated with model (both clock and topology) mis-specification are minimized, therefore reducing error in divergence-time estimation. We demonstrated the efficacy of this approach through simulation and applied it to published animal (Aves, Diplopoda, and Hymenoptera) and plant (carnivorous Caryophyllales, broad Caryophyllales, and Vitales) phylogenomic datasets. By quantifying rate heterogeneity across both genes and lineages we found that every empirical dataset examined included genes with clock-like, or nearly clock-like, behavior. Moreover, many datasets had genes that were clock-like, exhibited reasonable evolutionary rates, and were mostly compatible with the species tree. We identified overlap in age estimates when analyzing these filtered genes under strict clock and uncorrelated lognormal (UCLN) models. However, this overlap was often due to imprecise estimates from the UCLN model. We find that “gene shopping” can be an efficient approach to divergence-time inference for phylogenomic datasets that may otherwise be characterized by extensive gene tree heterogeneity