Calendars with Olympiad display and eclipse prediction on the Antikythera Mechanism
Tony Freeth1,2, Alexander Jones3, John M. Steele4 & Yanis Bitsakis1,5
Antikythera Mechanism Research Project, 3 Tyrwhitt Crescent, Roath Park, Cardiff CF23 5QP, UK
Images First Ltd, 10 Hereford Road, South Ealing, London W5 4SE, UK
Institute for the Study of the Ancient World, 15 East 84th Street, New York, New York 10028, USA
Department of Physics, University of Durham, Rochester Building, South Road, Durham DH1 3LE, UK
Centre for History and Palaeography, 3, P. Skouze str., GR-10560 Athens, Greece
Correspondence to: Tony Freeth1,2 Correspondence and requests for materials should be addressed to T.F. (Email: tony@images-first.com).
Top of pagePrevious research on the Antikythera Mechanism established a highly complex ancient Greek geared mechanism with front and back output dials1, 2, 3, 4, 5, 6, 7. The upper back dial is a 19-year calendar, based on the Metonic cycle, arranged as a five-turn spiral1, 6, 8. The lower back dial is a Saros eclipse-prediction dial, arranged as a four-turn spiral of 223 lunar months, with glyphs indicating eclipse predictions6. Here we add surprising findings concerning these back dials. Though no month names on the Metonic calendar were previously known, we have now identified all 12 months, which are unexpectedly of Corinthian origin. The Corinthian colonies of northwestern Greece or Syracuse in Sicily are leading contenders—the latter suggesting a heritage going back to Archimedes. Calendars with excluded days to regulate month lengths, described in a first century bc source9, have hitherto been dismissed as implausible10, 11. We demonstrate their existence in the Antikythera calendar, and in the process establish why the Metonic dial has five turns. The upper subsidiary dial is not a 76-year Callippic dial as previously thought8, but follows the four-year cycle of the Olympiad and its associated Panhellenic Games. Newly identified index letters in each glyph on the Saros dial show that a previous reconstruction needs modification6. We explore models for generating the unusual glyph distribution, and show how the eclipse times appear to be contradictory. We explain the four turns of the Saros dial in terms of the full moon cycle and the Exeligmos dial as indicating a necessary correction to the predicted eclipse times. The new results on the Metonic calendar, Olympiad dial and eclipse prediction link the cycles of human institutions with the celestial cycles embedded in the Mechanism's gearwork.
venerdì 1 agosto 2008
Letter
Nature 454, 614-617 (31 July 2008) | doi:10.1038/nature07130; Received 28 March 2008; Accepted 2 June 2008
lunedì 28 luglio 2008
Exploiting semantic web and ontologies for personalised learning services
Exploiting semantic web and ontologies for personalised learning services: towards semantic web-enabled learning portals for real learning experiences
by Maria Vargas-Vera, Miltiadis D. Lytras
International Journal of Knowledge and Learning (IJKL), Vol. 4, No. 1, 2008
Abstract: This paper presents an in-depth analysis of the semantic web contribution towards personalisation in e-learning content exploitation. The aim of this research work is to develop a framework for analysing the semantic web and ontological issues related with the design and implementation of high performance e-learning systems enabled by advanced semantic web and ontological engineering. Within this context the concept of personalisation is linked to the state of the art of semantic web and ontologies research. The main emphasis is paid to the management of personal profiles and identities. Real learning experiences are promoted through the definition of value-adding layers within semantic e-learning portals.
lunedì 21 luglio 2008
System for Information on Grey Literature in Europe
OpenSIGLE : Sistema per l'Informazione in Letteratura Grigia in Europa, è il vostro sito per l'accesso libero ai riferimenti bibliografici dei rapporti ed altre letterature grigie prodotti in Europa. La letteratura grigia comprende rapporti tecnici o di ricerca, tesi di dottorato, atti di congressi, preprints, publicazioni ufficiali, etc. SIGLE copre i campi delle scienze pure ed applicate, la tecnologia, l'economia, come pure le scienze umane e sociali.
lunedì 12 maggio 2008
lunedì 5 maggio 2008
Boolify
Boolify è una applicazione web che consente di creare stringhe di ricerca per Google grazie ad una semplice interfaccia visuale. Ovviamente è destinata ai piccoli o a chi non ha dimestichezza con gli operatori logici AND, OR e NOT.
Il funzionamento è semplice. E’ possibile trascinare in una board uno dei quattro pezzi stile puzzle utilizzabili, come si vede dallo screenshot: la chiave di ricerca (verde), l’operatore logico AND (blu), NOT (rosso), OR (giallo). Componendoli tra loro, incastrando i pezzi, si possono formare stringhe di ricerca anche complesse. Vedremo i risultati generati dal motore di Google di volta in volta, mentre aggiungiamo “tessere del puzzle” per affinare la ricerca.
Un buon sistema per imparare la logica booleana applicata al popolare motore di ricerca. Dopo il salto, un video su YouTube spiega il funzionamento meglio delle parole.
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