Human evaluation of Kea, an automatic keyphrasing system.

This paper describes an evaluation of the Kea automatic keyphrase extraction algorithm. Tools that automatically identify keyphrases are desirable because document keyphrases have numerous applications in digital library systems, but are costly and time consuming to manually assign. Keyphrase extraction algorithms are usually evaluated by comparison to author-specified keywords, but this methodology has several well-known shortcomings. The results presented in this paper are based on subjective evaluations of the quality and appropriateness of keyphrases by human assessors, and make a number of contributions. First, they validate previous evaluations of Kea that rely on author keywords. Second, they show Kea's performance is comparable to that of similar systems that have been evaluated by human assessors. Finally, they justify the use of author keyphrases as a performance metric by showing that authors generally choose good keywords

Interactive document summarisation.

This paper describes the Interactive Document Summariser (IDS), a dynamic document summarisation system, which can help users of digital libraries to access on-line documents more effectively. IDS provides dynamic control over summary characteristics, such as length and topic focus, so that changes made by the user are instantly reflected in an on-screen summary. A range of 'summary-in-context' views support seamless transitions between summaries and their source documents. IDS creates summaries by extracting keyphrases from a document with the Kea system, scoring sentences according to the keyphrases that they contain, and then extracting the highest scoring sentences. We report an evaluation of IDS summaries, in which human assessors identified suitable summary sentences in source documents, against which IDS summaries were judged. We found that IDS summaries were better than baseline summaries, and identify the characteristics of Kea keyphrases that lead to the best summaries

McGregor was more than just an exiled muso

Photocopied article form the newspaper Sowetan about Chris McGregor's death. There is a picture of Chris McGregor with this article

Product user testing: The void between laboratory testing and field testing

User testing will frequently make the difference between an excellent product and a poor one. Moreover, in certain fields such as medical device development or training, the defence field or automotive industry, such testing can literally be the difference between life and death. Unfortunately, design teams rarely have the luxury of either time or budget to user test every aspect of a design at every stage, and so knowing where and when to devote time to testing, and the fidelity required for accurate results are all critical to delivering a good result. This paper introduces research aimed at defining the optimum fidelity of mixed-reality user testing environments. It aims to develop knowledge enabling the optimisation of user testing environments by balancing effort vs. reward and thus developing critical and accurate data early in the design process. Testing in a laboratory setting brings advantages such as the ability to limit experimental variability, control confidentiality and measure performance in great detail. Its disadvantages over ‘in the wild’ approaches tend to be related to ecological validity and the small but vitally important changes in user behaviour in real life settings. Virtual reality and hybrid physical-virtual testing environments should theoretically give designers the best of both worlds, finding critical design flaws cheaply and early. However, many attempts have focussed on high fidelity, technology-rich approaches that make them simultaneously more expensive, less flexible and less accessible. The final result is that they are less viable and hence somewhat counter-productive. This paper presents the results of testing at a variety of fidelity levels within a mixed reality testing environment created by a team of artists and designers. It concludes with a series of recommendations regarding where and when fidelity is important

Microwave radar cross sections and Doppler velocities measured in the surf zone

Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 110 (2005): C12024, doi:10.1029/2005JC003022.The relationship between microwave imaging radar measurements of fluid velocities in the surf zone and shoaling, breaking, and broken waves is studied with field observations. Normalized radar cross section (NRCS) and Doppler velocity are estimated from microwave measurements at near-grazing angles, and in situ fluid velocities are measured with acoustic Doppler velocimeters (ADVs). Joint histograms of radar cross section and Doppler velocity cluster into identifiable distributions. The NRCS values from pixels with large NRCS and high Doppler velocities (>2 m/s) decrease with decreasing bore height to the shoreline, similar to scattering from a cylinder with decreasing radius. The Doppler velocities associated with these regions in the histograms agree well with theoretical wave phase velocities. Radar and ADV measurements of fluid velocities between bore crests have similarly shaped energy density spectra for frequencies above about 0.1 Hz, but energy levels from the radar are an order of magnitude higher than those of the ADV data. Instantaneous interbore Doppler velocities are correlated with ADV measured fluid velocities but are offset by 0.8 m/s. This offset may be due to Bragg wave phase velocities, wind drift, range and azimuth sidelobes, the finite spatial resolution of the radar, and differences between mean flows measured at the surface with radar and flows measured below the surface with ADVs. Shoaling and breaking waves measured through radar grating lobes significantly affect both the Doppler velocities near the edges of the images and the scattering from the rear faces of waves, causing large Doppler velocities to be observed in these regions.This work was funded by the ONR Coastal Geosciences Program