Measuring and comparing the reliability of the structured walkthrough evaluation method with novices and experts

Effective evaluation of websites for accessibility remains problematic. Automated evaluation tools still require a significant manual element. There is also a significant expertise and evaluator effect. The Structured Walkthrough method is the translation of a manual, expert accessibility evaluation process adapted for use by novices. The method is embedded in the Accessibility Evaluation Assistant (AEA), a web accessibility knowledge management tool. Previous trials examined the pedagogical potential of the tool when incorporated into an undergraduate computing curriculum. The results of the evaluations carried out by novices yielded promising, consistent levels of validity and reliability. This paper presents the results of an empirical study that compares the reliability of accessibility evaluations produced by two groups (novices and experts). The main results of this study indicate that overall reliability of expert evaluations was 76% compared to 65% for evaluations produced by novices. The potential of the Structured Walkthrough method as a useful and viable tool for expert evaluators is also examined. Copyright 2014 ACM

Age, Growth, Life History, and Fisheries of the Sand Sole, Psettichthys melanostictus

Sand sole, Psettichthys melanostictus, is a small but important part of the west coast groundfish fishery. It has never been assessed and there is a limited amount of biological data for the species. We provide the first estimates of age and growth for California populations and compare them with studies from other areas. We found that sand sole is a rapidly growing species which may show a strong latitudinal gradient in growth rate. We also found evidence of a recent, strong cohortrelated shift in the sex ratio of the population towards fewer females. In addition we examined data from the Washington, Oregon, and California commercial fishery to make an initial determination of population status. We found that catch per unit of effort in commercial trawls experienced a decline over time but has rebounded in recent years, except central California (the southern part of its commercial range), where the decline has not reversed

The Tagish Lake chondrite and the interstellar parent body hypothesis

Investigation of the solvent extractable organic compounds in Tagish Lake. The results are used to test the interstellar parent body hypthesis for the origin of extraterrestrial organic matter

Organic indicators of alteration in the CR chondrites

A study of the organic components in the CR chondrite macromolecule in order to assess the role of pre-terrestrial alteration on the organic inventory

Analysis of Tagish Lake macromolecular organic material

Macromolecular material is, by far, the major organic component of meteorites. Flash pyrolysis GCMS has been used to investigate this organic component in Tagish Lake. It is more condensed, less susbtituted than Murchson

The rocks from space initiative and the space safari

This paper reports the successes of a new initiative in the UK using electronic resources, such as virtual learning environments and e-classrooms, for planetary and space science public engagement activities

Coal feed component testing for CDIF

Investigations conducted during the conceptual design of the Montana MHD Component Development and Integration Facility (CDIF) identified commercially available processing and feeding equipment potentially suitable for use in a reference design. Tests on sub-scale units of this equipment indicated that they would perform as intended

Droplet size and morphology characterization for diesel sprays under atmospheric operating conditions

The shape of microscopic fuel droplets may differ from the perfect sphere, affecting their external surface area and thus the heat transfer with the surrounding gas. Hence there is a need for the characterization of droplet shapes, and the estimation of external surface area, in order to enable the development of physically accurate mathematical models for the heating and evaporation of diesel fuel sprays. We present ongoing work to automat-ically identify and reconstruct the morphology of fuel droplets, primarily focusing in this study on irregularly-shaped, partially-deformed and oscillating droplets under atmospheric conditions. We used direct imaging tech-niques based on long-working distance microscopy and ultra-high-speed video to conduct a detailed temporal investigation of droplet morphology. We applied purpose-built algorithms to extract droplet size, velocity, vol-ume and external surface area from the microscopic ultra-high-speed video frames. High resolution images of oscillating droplets and a formation of a droplet form ligament, sphericity factors, volume as well as external surface area are presented for 500 bar injection pressure in the near nozzle region (up to 0.7 mm from nozzle exit) under atmospheric conditions. We observed a range of different liquid structures, including perfectly spher-ical, non-spherical droplets and stretched ligaments. We found that large droplets and ligaments exceeding the size of the nozzle hole could be found at the end of injection. In order to estimate droplet volume and external surface area from two-dimensional droplet information, a discrete revolution of the droplet silhouette about its major centroidal axis was used. Special attention was paid to the estimation of actual errors in the prediction of volume and surface characteristics from a droplet silhouette. In addition to the estimation of droplet volume and external surface area, the actual shape reconstruction in 3D coordinates from a droplet silhouette was performed in order to enable future numerical modelling studies of real droplets