Introduction to the special issue on the 50th anniversary of IJHCS

This special issue celebrates the 50th anniversary of the International Journal of Human-Computer Studies (IJHCS), which published its first volume in January 1969. The special issue comprises 15 contributions from a number of experts in Human-Computer Interaction (HCI) and other areas relevant to IJHCS. These contributions are best characterized as ‘landscape papers’, providing insightful analyses about the evolution (i.e., the past, the present and the future) of research areas relevant to IJHCS. The areas covered in this special issue include: the history and scope of the journal; foundational concerns in HCI; critical discussions about the issues surrounding digital living in a variety of areas, from healthcare and cybersecurity to digital games and art; the making of interactive products and services, as seen through the viewpoints defined by research in psychology of programming, end-user development and participatory design; and, finally, the issues associated with adapting to various novel emerging technologies, including automated systems, online personalisation, human augmentations, mixed reality, and sonic interfaces. In this short essay, we introduce the special issue, reflecting on the nature and evolution of the journal, before providing short outlines of each of the contributions to this special issue

Global effects in quaternionic quantum field theory

We present some striking global consequences of a model quaternionic quantum field theory which is locally complex. We show how making the quaternionic structure a dynamical quantity naturally leads to the prediction of cosmic strings and non-baryonic hot dark matter candidates.Comment: 11 pages, no figures, revte

HypTrails: A Bayesian Approach for Comparing Hypotheses About Human Trails on the Web

When users interact with the Web today, they leave sequential digital trails on a massive scale. Examples of such human trails include Web navigation, sequences of online restaurant reviews, or online music play lists. Understanding the factors that drive the production of these trails can be useful for e.g., improving underlying network structures, predicting user clicks or enhancing recommendations. In this work, we present a general approach called HypTrails for comparing a set of hypotheses about human trails on the Web, where hypotheses represent beliefs about transitions between states. Our approach utilizes Markov chain models with Bayesian inference. The main idea is to incorporate hypotheses as informative Dirichlet priors and to leverage the sensitivity of Bayes factors on the prior for comparing hypotheses with each other. For eliciting Dirichlet priors from hypotheses, we present an adaption of the so-called (trial) roulette method. We demonstrate the general mechanics and applicability of HypTrails by performing experiments with (i) synthetic trails for which we control the mechanisms that have produced them and (ii) empirical trails stemming from different domains including website navigation, business reviews and online music played. Our work expands the repertoire of methods available for studying human trails on the Web.Comment: Published in the proceedings of WWW'1

Farming fit? Dispelling the Australian agrarian myth

Background: Rural Australians face a higher mental health and lifestyle disease burden (obesity, diabetes andcardiovascular disease) than their urban counterparts. Our ongoing research reveals that the Australian farmingcommunity has even poorer physical and mental health outcomes than rural averages. In particular, farm men andwomen have high rates of overweightness, obesity, abdominal adiposity, high blood pressure and psychologicaldistress when compared against Australian averages. Within our farming cohort we observed a significantassociation between psychological distress and obesity, abdominal adiposity and body fat percentage in thefarming population.Presentation of hypothesis: This paper presents a hypothesis based on preliminary data obtained from anongoing study that could potentially explain the complex correlation between obesity, psychological distress andphysical activity among a farming population. We posit that spasmodic physical activity, changing farm practicesand climate variability induce prolonged stress in farmers. This increases systemic cortisol that, in turn, promotesabdominal adiposity and weight gain.Testing the hypothesis: The hypothesis will be tested by anthropometric, biochemical and psychological analysismatched against systemic cortisol levels and the physical activity of the subjects.Implications of the hypothesis tested: Previous studies indicate that farming populations have elevated rates ofpsychological distress and high rates of suicide. Australian farmers have recently experienced challenging climaticconditions including prolonged drought, floods and cyclones. Through our interactions and through the media it isnot uncommon for farmers to describe the effect of this long-term stress with feelings of &lsquo;defeat&rsquo;. By gaining agreater understanding of the role cortisol and physical activity have on mental and physical health we maypositively impact the current rates of psychological distress in farmers.<br /

Emissivity spectrum of a large "dark streak" from themis infrared imagery

'Dark streaks', also known as 'slope streaks', are unusual surface features found on Mars that are known to appear and fade away on timescales of years. Various explanations have been proposed for their origin and composition, including dry avalanches and wet debris or precipitates from brines. Previous investigations have been based on analysis of panchromatic imagery and altimetry from Viking and Mars Global Surveyor missions. We have obtained an infrared emissivity spectrum of a large dark streak on the north western edge of Olympus Mons, using imagery from the THEMIS instrument on the Mars Odyssey 2001 spacecraft

Multi-particle Correlations in Quaternionic Quantum Systems

We investigate the outcomes of measurements on correlated, few-body quantum systems described by a quaternionic quantum mechanics that allows for regions of quaternionic curvature. We find that a multi-particle interferometry experiment using a correlated system of four nonrelativistic, spin-half particles has the potential to detect the presence of quaternionic curvature. Two-body systems, however, are shown to give predictions identical to those of standard quantum mechanics when relative angles are used in the construction of the operators corresponding to measurements of particle spin components.Comment: REVTeX 3.0, 16 pages, no figures, UM-P-94/54, RCHEP-94/1

The RAPTOR Experiment: A System for Monitoring the Optical Sky in Real Time

The Rapid Telescopes for Optical Response (RAPTOR) experiment is a spatially distributed system of autonomous robotic telescopes that is designed to monitor the sky for optical transients. The core of the system is composed of two telescope arrays, separated by 38 kilometers, that stereoscopically view the same 1500 square-degree field with a wide-field imaging array and a central 4 square-degree field with a more sensitive narrow-field "fovea" imager. Coupled to each telescope array is a real-time data analysis pipeline that is designed to identify interesting transients on timescales of seconds and, when a celestial transient is identified, to command the rapidly slewing robotic mounts to point the narrow-field ``fovea'' imagers at the transient. The two narrow-field telescopes then image the transient with higher spatial resolution and at a faster cadence to gather light curve information. Each "fovea" camera also images the transient through a different filter to provide color information. This stereoscopic monitoring array is supplemented by a rapidly slewing telescope with a low resolution spectrograph for follow-up observations of transients and a sky patrol telescope that nightly monitors about 10,000 square-degrees for variations, with timescales of a day or longer, to a depth about 100 times fainter. In addition to searching for fast transients, we will use the data stream from RAPTOR as a real-time sentinel for recognizing important variations in known sources. Altogether, the RAPTOR project aims to construct a new type of system for discovery in optical astronomy--one that explores the time domain by "mining the sky in real time".Comment: 11 pages, To appear in the Proceedings of the SPIE, Volume 484

Direct measurements of OH and other product yields from the HO2 + CH3C(O)O2 reaction

The reaction CH3C(O)O2 + HO2 → CH3C(O)OOH+O2 (Reaction R5a), CH3C(O)OH+O3 (Reaction R5b), CH3+CO2+OH+O2 (Reaction R5c) was studied in a series of experiments conducted at 1000 mbar and (293±2)K in the HIRAC simulation chamber. For the first time, products, (CH3C(O)OOH, CH3C(O)OH, O3 and OH) from all three branching pathways of the reaction have been detected directly and simultaneously. Measurements of radical precursors (CH3OH, CH3CHO), HO2 and some secondary products HCHO and HCOOH further constrained the system. Fitting a comprehensive model to the experimental data, obtained over a range of conditions, determined the branching ratios α(R5a) = 0.37±0.10, α(R5b) =0.12±0.04 and α(R5c) =0.51±0.12 (errors at 2σ level). Improved measurement/model agreement was achieved using k(R5) =(2.4±0.4)×10-11 cm3 molecule-1 s-1, which is within the large uncertainty of the current IUPAC and JPL recommended rate coefficients for the title reaction. The rate coefficient and branching ratios are in good agreement with a recent study performed by Groß et al. (2014b); taken together, these two studies show that the rate of OH regeneration through Reaction (R5) is more rapid than previously thought. GEOS-Chem has been used to assess the implications of the revised rate coefficients and branching ratios; the modelling shows an enhancement of up to 5% in OH concentrations in tropical rainforest areas and increases of up to 10% at altitudes of 6-8 km above the equator, compared to calculations based on the IUPAC recommended rate coefficient and yield. The enhanced rate of acetylperoxy consumption significantly reduces PAN in remote regions (up to 30 %) with commensurate reductions in background NOx

BreastScreening: On the Use of Multi-Modality in Medical Imaging Diagnosis

This paper describes the field research, design and comparative deployment of a multimodal medical imaging user interface for breast screening. The main contributions described here are threefold: 1) The design of an advanced visual interface for multimodal diagnosis of breast cancer (BreastScreening); 2) Insights from the field comparison of single vs multimodality screening of breast cancer diagnosis with 31 clinicians and 566 images, and 3) The visualization of the two main types of breast lesions in the following image modalities: (i) MammoGraphy (MG) in both Craniocaudal (CC) and Mediolateral oblique (MLO) views; (ii) UltraSound (US); and (iii) Magnetic Resonance Imaging (MRI). We summarize our work with recommendations from the radiologists for guiding the future design of medical imaging interfaces.Comment: AVI 2020 Short Papers, 5 pages, 2 figures, for associated files, see https://github.com/MIMBCD-UI/avi-2020-short-pape

Importance and vulnerability of the world’s water towers

Mountains are the water towers of the world, supplying a substantial part of both natural and anthropogenic water demands1,2. They are highly sensitive and prone to climate change3,4, yet their importance and vulnerability have not been quantified at the global scale. Here, we present a global Water Tower Index, which ranks all water towers in terms of their water-supplying role and the downstream dependence of ecosystems and society. For each tower, we assess its vulnerability related to water stress, governance, hydropolitical tension and future climatic and socio-economic changes. We conclude that the most important water towers are also among the most vulnerable, and that climatic and socio-economic changes will affect them profoundly. This could negatively impact 1.9 billion people living in (0.3 billion) or directly downstream of (1.6 billion) mountain areas. Immediate action is required to safeguard the future of the world’s most important and vulnerable water towers