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Wampum are traditional sacred shell beads of the Eastern Woodlands tribes of the indigenous people of North America . Wampum include the white shell beads fashioned from the North Atlantic channeled whelk shell; and the white and purple beads made from the quahog , or Western North Atlantic hard-shelled clam . Woven belts of wampum have been created to commemorate treaties or historical events, and for exchange in personal social transactions, such as marriages. In colonial North America , European colonists often used wampum as currency for trading with Native Americans . [ edit ] Description and manufacture The term initially referred to only the white beads, which are made of the inner spiral, or columella , of the Channeled whelk shell, Busycotypus canaliculatus or Busycotypus carica . [ 1 ] Sewant or suckauhock beads are the black or purple shell beads made from the quahog or poquahock clamshell, Mercenaria mercenaria .
Quipus (or khipus ), sometimes called talking knots , were recording devices historically used in the region of Andean South America . A quipu usually consisted of colored, spun, and plied thread or strings from llama or alpaca hair. It could also be made of cotton cords. The cords contained numeric and other values encoded by knots in a base ten positional system. Quipus might have just a few or up to 2,000 cords.
NativeTech: Native American Technology & Art Wampum from Middle and Late Woodland periods (beginning around AD 200) had a robust shape, about 8mm in length and 5mm in diameter, with larger stonebored holes of more than 2mm. Wampum beads of the mid-1600's average 5mm length and 4mm diameter with tiny holes were bored with European metal awls average 1mm. Seneca's in New York after European contact during the late 1600's had increasing numbers of shell beads which measured approximately 7mm length and 5mm diameter, having metaldrilled holes with a diameter of just under 2mm.
Example of application of the SOM: The Self-Organizing Map (SOM) can be used to portray complex correlations in statistical data. Here the data consisted of World Bank statistics of countries in 1992. Altogether 39 indicators describing various quality-of-life factors, such as state of health, nutrition, educational services, etc, were used. The complex joint effect of these factors can can be visualized by organizing the countries using the self-organizing map.