Framework for Electroencephalography-based Evaluation of User Experience

Measuring brain activity with electroencephalography (EEG) is mature enough to assess mental states. Combined with existing methods, such tool can be used to strengthen the understanding of user experience. We contribute a set of methods to estimate continuously the user's mental workload, attention and recognition of interaction errors during different interaction tasks. We validate these measures on a controlled virtual environment and show how they can be used to compare different interaction techniques or devices, by comparing here a keyboard and a touch-based interface. Thanks to such a framework, EEG becomes a promising method to improve the overall usability of complex computer systems.Comment: in ACM. CHI '16 - SIGCHI Conference on Human Factors in Computing System, May 2016, San Jose, United State

A Study of Snippet Length and Informativeness: Behaviour, Performance and User Experience

The design and presentation of a Search Engine Results Page (SERP) has been subject to much research. With many contemporary aspects of the SERP now under scrutiny, work still remains in investigating more traditional SERP components, such as the result summary. Prior studies have examined a variety of different aspects of result summaries, but in this paper we investigate the influence of result summary length on search behaviour, performance and user experience. To this end, we designed and conducted a within-subjects experiment using the TREC AQUAINT news collection with 53 participants. Using Kullback-Leibler distance as a measure of information gain, we examined result summaries of different lengths and selected four conditions where the change in information gain was the greatest: (i) title only; (ii) title plus one snippet; (iii) title plus two snippets; and (iv) title plus four snippets. Findings show that participants broadly preferred longer result summaries, as they were perceived to be more informative. However, their performance in terms of correctly identifying relevant documents was similar across all four conditions. Furthermore, while the participants felt that longer summaries were more informative, empirical observations suggest otherwise; while participants were more likely to click on relevant items given longer summaries, they also were more likely to click on non-relevant items. This shows that longer is not necessarily better, though participants perceived that to be the case - and second, they reveal a positive relationship between the length and informativeness of summaries and their attractiveness (i.e. clickthrough rates). These findings show that there are tensions between perception and performance when designing result summaries that need to be taken into account

Imagining Artificial Intelligence Applications with People with Visual Disabilities Using Tactile Ideation

There has been a surge in artificial intelligence (AI) technologies co-opted by or designed for people with visual disabilities. Researchers and engineers have pushed technical boundaries in areas such as computer vision, natural language processing, location inference, and wearable computing. But what do people with visual disabilities imagine as their own technological future? To explore this question, we developed and carried out tactile ideation workshops with participants in the UK and India. Our participants generated a large and diverse set of ideas, most focusing on ways to meet needs related to social interaction. In some cases, this was a matter of recognizing people. In other cases, they wanted to be able to participate in social situations without foregrounding their disability. It was striking that this finding was consistent across UK and India despite substantial cultural and infrastructural differences. In this paper, we describe a new technique for working with people with visual disabilities to imagine new technologies that are tuned to their needs and aspirations. Based on our experience with these workshops, we provide a set of social dimensions to consider in the design of new AI technologies: social participation, social navigation, social maintenance, and social independence. We offer these social dimensions as a starting point to forefront users' social needs and desires as a more deliberate consideration for assistive technology design

Bad news: analysis of the quality of information on influenza prevention returned by Google in English and Italian

Information available to the public influences the approach of the population toward vaccination against influenza compared with other preventative approaches. In this study, we have analyzed the first 200 websites returned by searching Google on two topics (prevention of influenza and influenza vaccine), in English and Italian. For all the four searches above, websites were classified according to their typology (government, commercial, professional, portals, etc.) and for their trustworthiness as defined by the Journal of the American Medical Association (JAMA) score, which assesses whether they provide some basic elements of information quality (IQ): authorship, currency, disclosure, and references. The type of information described was also assessed to add another dimension of IQ. Websites on influenza prevention were classified according to the type of preventative approach mentioned (vaccine, lifestyle, hygiene, complementary medicine, etc.), whether the approaches were in agreement with evidence-based medicine (EBM) or not. Websites on influenza vaccination were classified as pro- or anti-vaccine, or neutral. The great majority of websites described EBM approaches to influenza prevention and had a pro-vaccine orientation. Government websites mainly pointed at EBM preventative approaches and had a pro-vaccine orientation, while there was a higher proportion of commercial websites among those which promote non-EBM approaches. Although the JAMA score was lower in commercial websites, it did not correlate with the preventative approaches suggested or the orientation toward vaccines. For each of the four search engine result pages (SERP), only one website displayed the health-of-the-net (HON) seal. In the SERP on vaccines, journalistic websites were the most abundant category and ranked higher than average in both languages. Analysis using natural language processing showed that journalistic websites were mostly reporting news about two specific topics (different in the two languages). While the ranking by Google favors EBM approaches and, in English, does not promote commercial websites, in both languages it gives a great advantage to news. Thus, the type of news published during the influenza season probably has a key importance in orienting the public opinion due to its high visibility. This raises important questions on the relationships between health IQ, trustworthiness, and newsworthiness

Seasonal Energy and Water Balance of a \u3ci\u3ePhragmites Australis\u3c/i\u3e-Dominated Wetland in the Republican River Basin (Southwestern Nebraska, USA)

Climate and vegetation can dramatically alter the water cycle on local to regional scales. A change in the surface energy and water balance, especially in arid regions, can have significant impacts on local water availability and, therefore, water resource management. The purpose of this study is to understand the role of climate and vegetation in the energy and water balance of a riparian wetland in the central Great Plains. The site is located near the Republican River in southwestern Nebraska, where decreases in streamflow have been observed in recent decades. In an effort to reduce consumptive use from evapotranspiration (ET), and thereby reclaim surface water, invasive species such as Phragmites australis are being removed throughout the riparian corridor of the river basin. In this study, we have installed two energy/water balance monitoring stations, a Large Aperture Scintillometer (LAS), and various water and soil temperature probes in the P. australis and native (Typha latifolia) portions of the wetland to determine the energy and water balance during the 2009 growing season (April 11−October 3). Sensible heat flux is measured using the LAS, while ET is calculated as a residual of the energy balance (i.e., net radiation minus the sensible heat flux and heat storage in the canopy, water, and soil). Comparisons are also made with ET rates calculated from the simpler Priestley-Taylor method. Additional calculations of ET rates for both P. australis and T. latifolia (Cattail) were made using Landsat remote sensing imagery during five days from April 19 to September 26. Lastly, an open water evaporation model was developed to simulate the potential rate of evaporation from an open water body, in the absence of vegetation. The model assumes a shallow, well-mixed water layer that is similar in area and depth to the existing wetland, and the results are used to infer the potential amount of “water savings” that might be achieved by the removal of P. australis vegetation from the wetland. The results of the energy budget analysis show that the average ET rate for the wetland during the growing season is 4.4 mm day-1, with a maximum rate of 8.2 mm day-1 occurring around June 29. This measured daily ET is higher than some values found in previous studies (e.g., 6.9, 6.5, 6.3, 5.0, and 5.8 mm day-1) and is attributed to differences in plant structure/biology, environment, and regional climate. The vegetation phenology and net radiation are the two largest meteorological/vegetation drivers for the seasonal variability in ET. Remote sensing-based estimates of ET are similar than those of the in-situ energy balance during full vegetation, and they also reveal that the ET rates from P. australis are, on average, about 28% (1.18 mm day-1) greater than those for T. latifolia. We concluded that the Priestley-Taylor equation provides a good estimate of ET, particularly during the height of the growing season, when most of the net radiation is balanced by latent heat flux. Results of the water balance analysis reveal a reasonable correspondence between water level fluctuations and the energy budget-derived estimates of ET. Periods when the two curves do not agree imply influx (outflux) of groundwater early (late) in the growing season. Results suggest that the removal of P. australis from wetlands within the Republican River basin could potentially result in a growing season “water savings” of up to 28% if the native species of T. latifolia replaces the non-native P. australis. If a free water surface replaces P. australis, depending on wind sheltering, a “water loss” or a “water savings” could occur. We conclude that due to the general presence of wind sheltering throughout the riparian corridor of the Republican River basin, this would more likely lead to a small, but tangible amount of “water savings” if replaced by open water

What makes re-finding information difficult? A study of email re-finding

Re-nding information that has been seen or accessed before is a task which can be relatively straight-forward, but often it can be extremely challenging, time-consuming and frustrating. Little is known, however, about what makes one re-finding task harder or easier than another. We performed a user study to learn about the contextual factors that influence users' perception of task diculty in the context of re-finding email messages. 21 participants were issued re-nding tasks to perform on their own personal collections. The participants' responses to questions about the tasks combined with demographic data and collection statistics for the experimental population provide a rich basis to investigate the variables that can influence the perception of diculty. A logistic regression model was developed to examine the relationships be- tween variables and determine whether any factors were associated with perceived task diculty. The model reveals strong relationships between diculty and the time lapsed since a message was read, remembering when the sought-after email was sent, remembering other recipients of the email, the experience of the user and the user's ling strategy. We discuss what these findings mean for the design of re-nding interfaces and future re-finding research

HIV prevention trial design in an era of effective pre-exposure prophylaxis

Pre-exposure prophylaxis (PrEP) has demonstrated remarkable effectiveness protecting at-risk individuals from HIV-1 infection. Despite this record of effectiveness, concerns persist about the diminished protective effect observed in women compared with men and the influence of adherence and risk behaviors on effectiveness in targeted subpopulations. Furthermore, the high prophylactic efficacy of the first PrEP agent, tenofovir disoproxil fumarate/emtricitabine (TDF/FTC), presents challenges for demonstrating the efficacy of new candidates. Trials of new agents would typically require use of non-inferiority (NI) designs in which acceptable efficacy for an experimental agent is determined using pre-defined margins based on the efficacy of the proven active comparator (i.e. TDF/FTC) in placebo-controlled trials. Setting NI margins is a critical step in designing registrational studies. Under- or over-estimation of the margin can call into question the utility of the study in the registration package. The dependence on previous placebo-controlled trials introduces the same issues as external/historical controls. These issues will need to be addressed using trial design features such as re-estimated NI margins, enrichment strategies, run-in periods, crossover between study arms, and adaptive re-estimation of sample sizes. These measures and other innovations can help to ensure that new PrEP agents are made available to the public using stringent standards of evidence

An Analysis of Class in Composition from 1970-2010

Class and socioeconomic status in composition and rhetoric remains a topic that is felt, yet not often discussed. The language students use is highly indicative of their class background, and everyone has a slightly altered form of discourse they prefer (Zebroski, 2006). My thesis examines the issues working-class students have faced with literacy acquisition and discourse assimilation from 1970s–mid 2000s. My analysis illustrates how composition and rhetoric has evolved from the error-centered and hyper-correct culture of the 1970s to the technologically dominated, media driven production powerhouse that affects every aspect of college and beyond. To most effectively address how working-class student language usage within composition classrooms has evolved, this project includes a metanalysis from the 1970s to mid 2000s of composition and rhetoric scholarship that deals with working-class college students and pedagogical shifts in first-year writing. This analysis reveals that instructors who validate socioeconomic diversity in language employ teaching practices that enable working-class students to draw from their culture and linguistic backgrounds, their narratives of self, and their own lives outside of the classroom. My findings gesture towards another major shift for the future of composition and rhetoric, one that accepts greater student diversity in language and class background; recognizes more varied forms of academic writing that include narratives and collaboration; and encourages the acquisition of different types of multimedia literacies

Classified displays of web search results.

Most text retrieval systems return a ranked list of results in response to a user's search request. Such lists can be long and overwhelming. Furthermore, results on different topics or different aspects of the same topic are intermixed in the list requiring users to sift through a long undifferentiated list to find items of interest. We have been exploring the use of automatic text classification techniques combined with novel interface ideas to allow users to quickly focus in on results of interest. Our approach combines the advantages of human knowledge in an initial classification stage with the broad coverage available with text retrieval systems. In a series of user studies we developed and evaluated several interfaces for structuring search results in order to better understand the cognitive processes that lead to effective analysis of search results. There are two key aspects to our work that we describe in more detail: 1) automatic text classification algorithms for quickly and accurately tagging ew content, and 2) novel interface to support structured search