The Contrast Sensitivity Function
Prepared by Peter Wenderoth
Imagine that you are driving a car in a very thick fog. Objects which are normally easily seen, like black writing on a white billboard, will be hard to see because the black writing and the white background will both be greyish. That is the difference between whites and blacks - contrast - will be reduced
The Digital Library of Mathematical Functions (DLMF) Project was initiated to perform a complete revision of Abramowitz and Stegun’s Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, published in 1964 by the National Bureau of Standards. See R. F. Boisvert and D. W. Lozier (2001) for historical background about this important publication. The DLMF Project has updated and expanded the coverage for current needs. The results have been published in book form as the NIST Handbook of Mathematical Functions, by Cambridge University Press, and disseminated in the free electronic Digital Library of Mathematical Functions. For further details about the project see Preface.
Hi folks, This time I'm in some trouble. Please help me in this issue. My site will have forms with number of text fields, I'll store the form data in MySQL database and later those data will be fetched and populated on web pages. Now, the forms are filled up by users, so I need to escape all unwanted characters while keeping the necessary ones intact. Suppose I get a field data in the form of $_POST. So far I was using combination of mysql_real_escape_string, htmlentities, striptags
CREATE FUNCTION pg_catalog.text(integer) RETURNS text STRICT IMMUTABLE LANGUAGE SQL AS 'SELECT textin(int4out($1));';
CREATE CAST (integer AS text) WITH FUNCTION pg_catalog.text(integer) AS IMPLICIT;
Die Levenshtein-Distanz ist eine effiziente Möglichkeit, die Ähnlichkeit von Strings zu bestimmen, Damit können beispielsweise Tippfehler bei der Verwendung von Suchfunktionen elegant korrigiert werden. Wenn man eine Anzeige im Stile von "Meinten Sie vielleicht ..." anzeigen möchte, braucht man hierzu eine Funktion die "das ähnlichste" Wort in einer Datenbanktabelle findet. Hierzu habe ich eine MySQL-GROUP-Funktion geschrieben.