Alan Gilchrist – författare
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21 produkter
21 produkter
E-bok
Engelska, 2006997 kr
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How the human visual system determines the lightness of a surface, that is, its whiteness, blackness, or grayness, remains--like vision in general--a mystery. In fact, we have not even been able to create a machine that can determine, through an artificial vision system, whether an object is white, black, or gray. Although the photoreceptors in the eye are driven by light, the light reflected by a surface does not reveal its shade of gray. Depending upon the level of illumination, a surface of any shade of gray can reflect any amount of light.In Seeing Black and White Alan Gilchrist ties together over 30 years of his own research on lightness, and presents the first comprehensive, historical review of empirical work on lightness, covering the past 150 years of research on images ranging from the simple to the complex. He also describes and analyzes the many theories of lightness--including his own--showing what each can and cannot explain. Gilchrist highlights the forgotten-yet-exciting work done in the first third of the twentieth century, describing several crucial experiments and examining the brilliant but nearly unknown work of the Hungarian gestalt theorist, Lajos Kardos. Gilchrists review also includes a survey of the pattern of lightness errors made by humans, many of which result in delightful illusions. He argues that because these errors are not random, but systematic, they are the signature of our visual software, and so provide a powerful tool that can reveal how lightness is computed. Based on this argument and the concepts of anchoring, grouping, and frames of reference, Gilchrist presents a new theoretical framework that explains an unprecedented array of lightness errors. As both the first comprehensive overview of research on lightness and the first unified presentation of Gilchrists new theoretical framework Seeing Black and White will be an invaluable resource for vision scientists, cognitive psychologists, and cognitive neuroscientists.
Inbunden, Engelska, 2006
1 314 kr
Skickas inom 5-8 vardagar
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.
E-bok
PDF, Engelska, 2006997 kr
Läs direkt efter köp
How the human visual system determines the lightness of a surface, that is, its whiteness, blackness, or grayness, remains--like vision in general--a mystery. In fact, we have not even been able to create a machine that can determine, through an artificial vision system, whether an object is white, black, or gray. Although the photoreceptors in the eye are driven by light, the light reflected by a surface does not reveal its shade of gray. Depending upon the level of illumination, a surface of any shade of gray can reflect any amount of light.In Seeing Black and White Alan Gilchrist ties together over 30 years of his own research on lightness, and presents the first comprehensive, historical review of empirical work on lightness, covering the past 150 years of research on images ranging from the simple to the complex. He also describes and analyzes the many theories of lightness--including his own--showing what each can and cannot explain. Gilchrist highlights the forgotten-yet-exciting work done in the first third of the twentieth century, describing several crucial experiments and examining the brilliant but nearly unknown work of the Hungarian gestalt theorist, Lajos Kardos. Gilchrists review also includes a survey of the pattern of lightness errors made by humans, many of which result in delightful illusions. He argues that because these errors are not random, but systematic, they are the signature of our visual software, and so provide a powerful tool that can reveal how lightness is computed. Based on this argument and the concepts of anchoring, grouping, and frames of reference, Gilchrist presents a new theoretical framework that explains an unprecedented array of lightness errors. As both the first comprehensive overview of research on lightness and the first unified presentation of Gilchrists new theoretical framework Seeing Black and White will be an invaluable resource for vision scientists, cognitive psychologists, and cognitive neuroscientists.
Häftad, Engelska, 2000
1 394 kr
Skickas inom 10-15 vardagar
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.
E-bok
Engelska, 20031 657 kr
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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.
E-bok
PDF, Engelska, 20031 657 kr
Läs direkt efter köp
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.
Häftad, Engelska, 2017
357 kr
Skickas inom 5-8 vardagar
Häftad, Engelska, 2018
251 kr
Skickas inom 5-8 vardagar
E-bok
Engelska, 202067 kr
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The author's father was the manager of a biscuit factory in an industrial area of north west London. He had served in the Great War, and after the war his first wife died in the 1919 flu pandemic, leaving him with a young daughter. He remarried and had another four children, Alan being the second. With scant formal education themselves, he and his wife were able to offer all the children a good education, and to Alan a medical one as well. It was during a biology class in his first year in the medical school that the author first heard about two streams of blood in the same chamber of the heart. In 1956, 'by a set of curious chances' (The Mikado), the author found himself in the setting he had dreamt about when he was a little boy: practising medicine in rural Africa. This was in Nyasaland, part of the former Central African Federation of Rhodesia and Nyasaland. (Now Zambia, Zimbabwe and Malawi). In 1962 he was posted to Zomba as medical superintendent and met Pauline who had been born in the same hospital 21 years previously. The following year they were married, and immediately after the reception left for Fort Victoria in Rhodesia, where he had been offered the post of medical superintendent. Those were momentous times: bringing up a young family in a rapidly changing African environment and practising medicine in the midst of it. The story would make interesting reading, but the author has put it aside and only shown the details of his investigations of the foetal circulation in his little book.
Häftad, Engelska, 2020
177 kr
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E-bok
Engelska, 202167 kr
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The Book. It is in two sections, the first describing the author's experiences as a government medical officer in southern Africa in the middle of the last century, which led to his finding the long-hidden secrets of the foetal circulation. The second describes how he uncovered the secrets, and gives an account of each part which completely demolishes the long-held orthodox accounts. The foetal heart sounds are described which may be heard with a Doppler foetal heart monitor. The birth changes, which no one has ever seen, and probably never will, are guessed at in full detail.
Häftad, Engelska, 2021
161 kr
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Häftad, Engelska, 2019
276 kr
Skickas inom 5-8 vardagar
Inbunden, Engelska, 2012
1 549 kr
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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.
E-bok
PDF, Engelska, 20131 160 kr
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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 Vickery The developing foundations of information science, by David Bawden The last 50 years of knowledge organization, by Stella G Dextre Clarke On the history of evaluation in IR, by Stephen Robertson The information user, by Tom Wilson The sociological turn in information science, by Blaise Cronin From chemical documentation to chemoinformatics, by Peter Willett Health informatics, by Peter A Bath Social informatics and sociotechnical research, by Elisabeth Davenport The evolution of visual information retrieval, by Peter Enser Information policies, by Elizabeth Orna Disparity in professional qualifications and progress in information handling, by Barry Mahon Electronic scholarly publishing and open access, by Charles Oppenheim Social software: fun and games, or business tools?, by Wendy A Warr Bibliometrics 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.
Häftad, Engelska, 2015
372 kr
Skickas inom 3-6 vardagar
Häftad, Engelska, 2024
260 kr
Skickas inom 5-8 vardagar
Häftad, Engelska, 2024
194 kr
Skickas inom 5-8 vardagar
Häftad, Engelska, 2025
172 kr
Skickas inom 5-8 vardagar
Häftad, Engelska, 2025
172 kr
Skickas inom 5-8 vardagar
Inbunden, Engelska, 2009
1 228 kr
Tillfälligt slut
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.