Alan Gilchrist – författare

Most people are surprised to learn that seeing has not yet been explained by science. Incredibly, scientists cannot even explain why some surfaces appear to be black while others appear to be white. The physical difference between a surface that appears to be black and one that appears to be white results from the percentage ot light that the object reflects, known as reflectance. A white surface reflects 30 times more light into the eye than a black surface. The amount of light reflected by a surface into the eye is, however, a product of more than its own reflectance; it is also a product of the intensity of illumination it receives. A sheet of white paper lying within a shadow can easily reflect the same absolute amount of light as a sheet of black paper lying outside the shadow. Thus, there is essentially no correlation between the amount of light reflected by a suface and its physical shade: a black paper in a bright light and a white paper in shadow reflect identical light to the eye. Still, the black paper appears to be black and the white paper appears to be white. How can it be? Somehow the visual system must use the surrounding context. But how? Good thinkers have struggled with this problem for over a thousand years, and the last 150 years have witnessed a sustained assault on the problem. In this volume, Alan Gilchrist, one of the leading researchers in achromatic perception, reviews the history of the scientific development of lightness theory from the nineteenth century until the present and outlines and critiques all the main theories of lightness, laying out the strengths and weaknesses of each. Based on thirty years of research, Gilchrist presents his own argument that previous models of lightness perception are too good because they fail to capture the errors and illusions present in human perception. These errors may contain crucial clues in the sense that the overall pattern of errors is the signature of the human visual system.

A practical guide to the construction of thesauri for use in information retrieval, written by leading experts in the field. Includes: planning and design; vocabulary control; specificity and compound terms; structure and relationships; auxiliary retrieval devices; multilingual thesauri; AAT Compound Term Rules. The US ANSI/NISO Z39.19 Thesaurus construction standard is also covered.

The ISKO UK Biennial Conference, 4th - 5th July, 2011, London honoured the life and achievements of Brian C. Vickery. His influence on the development of the information profession is celebrated in this book, with contributions from over 50 authors to address research and developments in knowledge organization, ranging from the theoretical basis of information retrieval to the practical application of ontologies in driving news and sport presentation on the BBC website. ISKO UK is a not-for-profit scientific/professional association with the objective of promoting research and communication in the domain of knowledge organization, within the broad field of information science and related disciplines.

Are we at a turning point in digital information? The expansion of the internet was unprecedented; search engines dealt with it in the only way possible - scan as much as they could and throw it all into an inverted index. But now search engines are beginning to experiment with deep web searching and attention to taxonomies, and the Semantic Web is demonstrating how much more can be done with a computer if you give it knowledge. What does this mean for the skills and focus of the information science (or sciences) community? Should information designers and information managers work more closely to create computer based information systems for more effective retrieval? Will information science become part of computer science and does the rise of the term informatics demonstrate the convergence of information science and information technology - a convergence that must surely develop in the years to come? Issues and questions such as these are reflected in this monograph, a collection of essays written by some of the most pre-eminent contributors to the discipline. These peer reviewed perspectives capture insights into advances in, and facets of, information science, a profession in transition. With an introduction from Jack Meadows the key papers are:Meeting the challenge, by Brian VickeryThe developing foundations of information science, by David BawdenThe last 50 years of knowledge organization, by Stella G Dextre ClarkeOn the history of evaluation in IR, by Stephen RobertsonThe information user, by Tom WilsonThe sociological turn in information science, by Blaise CroninFrom chemical documentation to chemoinformatics, by Peter WillettHealth informatics, by Peter A BathSocial informatics and sociotechnical research, by Elisabeth DavenportThe evolution of visual information retrieval, by Peter EnserInformation policies, by Elizabeth OrnaDisparity in professional qualifications and progress in information handling, by Barry MahonElectronic scholarly publishing and open access, by Charles OppenheimSocial software: fun and games, or business tools?, by Wendy A WarrBibliometrics to webometrics, by Mike Thelwall. This monograph previously appeared as a special issue of the Journal of Information Science, published by Sage. Readership: Reproduced here as a monograph, this important collection of perspectives on a skill in transition from a prestigious line-up of authors will now be available to information studies students worldwide and to all those working in the information science field.