1967:
1979:
1991:
177:
Units of length, along with mass (or weight) and time, are one of the earliest quantities that was measured by man. Historically two distinct approaches were used – one was to use a naturally occurring phenomenon such as a particular seed or part of the human body, the other was to use a standard
79:
identifies three distinct ways in which this is done – the first being the realisation of a measurement unit from its definition, the second the reproduction of measurement standards and the third the process of actually adopting a particular artefact as a standard.
133:. The third phase made use of clocks that were sufficiently accurate that they could measure variations in the Earth's rotation – such clocks taking over from the rotation of the earth as the prime measure of time.
693:
493:
75:
The Oxford
English Dictionary defines the word "realise" (also spelt "realize") as "to convert (something imagined, planned, etc.) into real existence or fact". The
738:
688:
404:
369:
56:
732:
1260:
1007:
1380:
1285:
1280:
997:
817:
235:
1947:
1316:
1311:
1265:
916:
906:
807:
76:
34:
1422:
1321:
891:
829:
486:
1931:
1255:
1042:
1295:
1270:
1123:
871:
1179:
698:
428:"Practical realisation of the definition of the metre, including recommended radiations of other optical frequency standards (2001)"
1760:
1149:
1113:
1022:
760:
1235:
1220:
1174:
1052:
1027:
1012:
972:
896:
479:
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1133:
1103:
1073:
1037:
962:
881:
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846:
839:
543:
1926:
1373:
1225:
1200:
1164:
1128:
1108:
1098:
1083:
1078:
1068:
977:
901:
802:
533:
523:
64:
1290:
1210:
1169:
1159:
1088:
992:
931:
926:
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861:
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662:
581:
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1118:
1093:
1032:
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921:
812:
775:
744:
1775:
1627:
1154:
1002:
936:
834:
780:
770:
2017:
1995:
1047:
586:
342:
1971:
1366:
1655:
610:
561:
347:
1983:
1675:
1478:
93:
The realisation of time has gone through three phases. During both the first and second phases, man used
1952:
1665:
1535:
502:
1815:
1790:
1745:
1593:
1588:
1550:
1525:
442:
45:
395:
1690:
1583:
1275:
795:
726:
98:
1978:
1820:
1755:
1735:
1725:
1685:
1670:
1645:
1603:
1598:
1452:
1442:
1437:
790:
566:
427:
397:
International vocabulary of metrology—Basic and general concepts and associated terms (VIM)
290:
1885:
1800:
1740:
1710:
1635:
1493:
1488:
1412:
265:
186:
130:
355:
1880:
1750:
1612:
1563:
1545:
822:
450:
260:
1850:
1835:
1810:
1785:
1705:
1700:
1660:
1578:
1573:
1568:
1483:
1432:
1389:
987:
126:
30:
446:
1905:
1900:
1895:
1865:
1840:
1830:
1825:
1795:
1720:
1715:
1680:
1640:
1608:
1530:
1515:
1447:
1417:
1337:
911:
528:
254:
241:
199:
2011:
1890:
1805:
1765:
1650:
1473:
1457:
785:
657:
625:
597:
454:
281:
277:
182:
1870:
1770:
1695:
1342:
630:
620:
605:
373:
336:
60:
1860:
1855:
1845:
1780:
1520:
1407:
941:
672:
571:
312:
190:
122:
110:
1875:
1730:
94:
1540:
1427:
146:
114:
106:
22:
471:
1347:
142:
102:
1397:
1017:
97:– during the first phase, realisation of time was by observing the
1358:
374:"Practical realization of the definitions of some important units"
206:
118:
1362:
475:
407:
on behalf of the Joint
Committee for Guides in Metrology. 2012
16:
Conversion of the definition of a unit of measure into reality
205:
An example of a modern realisation is the realisation of the
33:
is the conversion of its definition into reality. The
41:
Realisation of a measurement unit from its definition.
1940:
1914:
1626:
1502:
1466:
1396:
1330:
1304:
1248:
1188:
1142:
1061:
950:
753:
719:
712:
681:
650:
643:
596:
554:
516:
509:
335:
37:identifies three distinct methods of realisation:
59:maintains the techniques for realisation of the
178:length that was held by a community leader.
1374:
487:
51:Adopting a particular artefact as a standard.
8:
405:International Bureau of Weights and Measures
370:International Bureau of Weights and Measures
57:International Bureau of Weights and Measures
1508:
1381:
1367:
1359:
716:
647:
513:
494:
480:
472:
209:in terms of optical frequency standards.
234:Artefacts held by governments (e.g. the
324:
236:International Prototype of the Kilogram
125:rather than elapsed time, clocks were
121:were used. If the user needed to know
330:
328:
77:International vocabulary of metrology
35:International vocabulary of metrology
7:
1990:
356:participating institution membership
195:Regal units – measures held by ruler
1932:Systems theory in political science
524:International System of Units (SI)
109:. During the second phase actual
14:
1989:
1977:
1966:
1965:
137:Direct measurement of solar time
1922:Systems theory in anthropology
1:
1927:Systems theory in archaeology
534:US customary units (USCS/USC)
65:International System of Units
2034:
455:10.1088/0026-1394/40/2/316
218:Jugs etc. in ancient times
168:Radiation frequency and SI
101:using such devices as the
1961:
1559:
1511:
1423:Coupled human–environment
587:English Engineering Units
343:Oxford English Dictionary
261:force between conductors
1756:Charles A. S. Hall
626:Quantum chromodynamical
348:Oxford University Press
313:Development of the mole
244:and Avogadro experiment
1676:Ludwig von Bertalanffy
739:centimetre–gram–second
503:Systems of measurement
302:Sensitivity of the eye
266:charge on the electron
1953:Principia Cybernetica
1666:Anthony Stafford Beer
1536:Sociotechnical system
1261:Biblical and Talmudic
727:metre–kilogram–second
426:Quinn, T. J. (2003).
221:Not a base unit in SI
46:measurement standards
1816:Mihajlo D. Mesarovic
1791:Edward Norton Lorenz
1746:Jay Wright Forrester
1551:World-systems theory
1526:Earth system science
1691:Kenneth E. Boulding
447:2003Metro..40..103Q
346:(Online ed.).
307:Amount of substance
1821:James Grier Miller
1776:Faina M. Kirillova
1736:Heinz von Foerster
1726:Edsger W. Dijkstra
1686:Alexander Bogdanov
1671:Richard E. Bellman
1646:William Ross Ashby
733:metre–tonne–second
529:UK imperial system
291:Boltzmann constant
287:Non-linearity etc.
158:Accuracy of clocks
2005:
2004:
1886:Manuela M. Veloso
1801:Humberto Maturana
1741:Stephanie Forrest
1711:C. West Churchman
1636:Russell L. Ackoff
1622:
1621:
1494:Positive feedback
1489:Negative feedback
1356:
1355:
1244:
1243:
708:
707:
699:Foot–pound–second
639:
638:
616:Heaviside–Lorentz
354:(Subscription or
131:astronomical time
2025:
2018:Systems of units
1993:
1992:
1981:
1969:
1968:
1881:Francisco Varela
1613:Systems thinking
1546:Urban metabolism
1509:
1383:
1376:
1369:
1360:
823:Mesures usuelles
717:
648:
514:
496:
489:
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473:
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432:
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403:(3rd ed.).
402:
392:
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366:
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351:
339:
332:
99:Earth's rotation
44:Reproduction of
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2027:
2026:
2024:
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2022:
2008:
2007:
2006:
2001:
1957:
1936:
1910:
1851:Anatol Rapoport
1836:Talcott Parsons
1811:Donella Meadows
1786:Allenna Leonard
1706:Mary Cartwright
1701:Kathleen Carley
1661:Gregory Bateson
1656:Béla H. Bánáthy
1618:
1555:
1504:
1498:
1484:Limiting factor
1479:Leverage points
1462:
1400:
1392:
1390:Systems science
1387:
1357:
1352:
1326:
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1240:
1184:
1138:
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274:
251:
249:Electric charge
228:
215:
175:
165:
163:Time generators
155:
139:
91:
86:
73:
31:unit of measure
17:
12:
11:
5:
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2029:
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2020:
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1911:
1909:
1908:
1906:Anthony Wilden
1903:
1901:Jennifer Wilby
1898:
1896:Norbert Wiener
1893:
1888:
1883:
1878:
1873:
1868:
1866:Claude Shannon
1863:
1858:
1853:
1848:
1843:
1841:Ilya Prigogine
1838:
1833:
1831:Howard T. Odum
1828:
1826:Radhika Nagpal
1823:
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1796:Niklas Luhmann
1793:
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1721:George Dantzig
1718:
1716:Manfred Clynes
1713:
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1683:
1681:Margaret Boden
1678:
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1641:Victor Aladjev
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1531:Living systems
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1516:Control theory
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1338:Absolute scale
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255:Silver nitrate
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242:Kibble balance
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200:speed of light
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111:timing devices
90:
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72:
69:
53:
52:
49:
42:
15:
13:
10:
9:
6:
4:
3:
2:
2030:
2019:
2016:
2015:
2013:
1998:
1997:
1988:
1986:
1985:
1980:
1976:
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1964:
1963:
1960:
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1946:
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1941:Organizations
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1933:
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1920:
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1917:
1913:
1907:
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1902:
1899:
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1894:
1892:
1891:Kevin Warwick
1889:
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1809:
1807:
1806:Margaret Mead
1804:
1802:
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1792:
1789:
1787:
1784:
1782:
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1777:
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1769:
1767:
1766:Lydia Kavraki
1764:
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1759:
1757:
1754:
1752:
1751:Barbara Grosz
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1651:Ruzena Bajcsy
1649:
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1514:
1513:
1510:
1507:
1501:
1495:
1492:
1490:
1487:
1485:
1482:
1480:
1477:
1475:
1474:Doubling time
1472:
1471:
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1333:
1329:
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1313:
1310:
1309:
1307:
1305:List articles
1303:
1297:
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1219:
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1214:
1212:
1209:
1207:
1204:
1202:
1199:
1197:
1194:
1193:
1191:
1189:South America
1187:
1181:
1178:
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1173:
1171:
1168:
1166:
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1153:
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1147:
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1143:North America
1141:
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1127:
1125:
1124:South African
1122:
1120:
1117:
1115:
1112:
1110:
1107:
1105:
1102:
1100:
1097:
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1080:
1077:
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1026:
1024:
1021:
1019:
1016:
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1009:
1006:
1004:
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994:
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989:
986:
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928:
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918:
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913:
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908:
905:
903:
900:
898:
895:
893:
890:
888:
885:
883:
880:
878:
875:
873:
872:Luxembourgian
870:
868:
865:
863:
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858:
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850:
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841:
838:
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833:
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819:
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797:
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782:
779:
777:
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772:
769:
767:
764:
762:
759:
758:
756:
752:
746:
745:gravitational
743:
740:
737:
734:
731:
728:
725:
724:
722:
718:
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562:Apothecaries'
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183:Natural units
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19:
1994:
1982:
1970:
1915:Applications
1871:Katia Sycara
1771:James J. Kay
1761:Mike Jackson
1696:Murray Bowen
1594:Pharmacology
1589:Neuroscience
1286:Mesopotamian
1180:Puerto Rican
577:Astronomical
458:. Retrieved
438:
434:
421:
409:. Retrieved
396:
390:
378:. Retrieved
376:. p. 46
364:
341:
204:
176:
127:synchronised
92:
74:
54:
26:
20:
18:
1861:Peter Senge
1856:John Seddon
1846:Qian Xuesen
1781:George Klir
1584:Engineering
1521:Cybernetics
1503:Theoretical
1453:Recommender
1443:Multi-agent
1438:Information
1150:Costa Rican
1114:Seychellois
1023:Singaporean
818:Traditional
673:Metrication
611:Geometrised
567:Avoirdupois
441:: 103–133.
272:Temperature
153:Timekeepers
123:time-of-day
115:hourglasses
27:realisation
1876:Eric Trist
1731:Fred Emery
1628:Scientists
1604:Psychology
1599:Philosophy
1428:Ecological
1413:Biological
1236:Venezuelan
1221:Paraguayan
1175:Nicaraguan
1053:Vietnamese
1028:Sri Lankan
1013:Philippine
973:Indonesian
897:Portuguese
791:Winchester
694:Comparison
644:Background
582:Electrical
460:6 December
435:Metrologia
358:required.)
319:References
297:Photometry
187:barleycorn
147:astrolabes
95:solar time
84:Techniques
61:base units
1541:Systemics
1231:Uruguayan
1216:Colombian
1206:Brazilian
1196:Argentine
1134:Tanzanian
1104:Mauritian
1074:Ethiopian
1038:Taiwanese
1008:Pakistani
988:Mongolian
963:Cambodian
882:Norwegian
852:Icelandic
847:Hungarian
840:Byzantine
796:Exchequer
544:Hong Kong
337:"Realise"
107:astrolabe
23:metrology
2012:Category
1972:Category
1574:Dynamics
1564:Analysis
1467:Concepts
1433:Economic
1317:Obsolete
1312:Humorous
1266:Egyptian
1226:Peruvian
1201:Bolivian
1165:Honduran
1129:Tunisian
1109:Moroccan
1099:Malagasy
1084:Eritrean
1079:Egyptian
1069:Algerian
998:Nepalese
978:Japanese
912:Scottish
902:Romanian
803:Estonian
713:Historic
689:Overview
658:Overview
555:Specific
411:26 April
380:23 April
372:(2012).
278:freezing
257:deposits
143:Sundials
113:such as
71:Overview
1996:Commons
1579:Ecology
1569:Biology
1448:Nervous
1418:Complex
1348:Modulor
1322:Unusual
1291:Persian
1249:Ancient
1211:Chilean
1170:Mexican
1160:Haitian
1089:Guinean
993:Myanmar
932:Swedish
927:Spanish
917:Serbian
907:Russian
887:Ottoman
877:Maltese
867:Latvian
862:Italian
808:Finnish
786:English
766:Cypriot
761:Cornish
668:History
663:Outline
598:Natural
539:Chinese
517:General
510:Current
443:Bibcode
282:boiling
103:sundial
63:in the
1984:Portal
1609:Theory
1505:fields
1458:Social
1398:System
1343:N-body
1281:Indian
1256:Arabic
1119:Somali
1094:Libyan
1062:Africa
1033:Syrian
983:Korean
968:Indian
958:Afghan
922:Slovak
892:Polish
830:German
813:French
776:Danish
754:Europe
720:Metric
651:Metric
631:Stoney
621:Planck
606:Atomic
280:&
231:Grains
213:Volume
198:Using
173:Length
119:clocks
67:(SI).
25:, the
1401:types
1331:Other
1296:Roman
1276:Hindu
1271:Greek
1155:Cuban
1043:Tatar
1003:Omani
942:Welsh
937:Swiss
857:Irish
835:Greek
781:Dutch
771:Czech
741:(CGS)
735:(MTS)
729:(MKS)
701:(FPS)
682:UK/US
431:(PDF)
401:(PDF)
352:
284:water
207:metre
129:with
29:of a
1948:List
1048:Thai
1018:Pegu
951:Asia
589:(US)
572:Troy
462:2013
413:2013
382:2013
226:Mass
191:feet
145:and
89:Time
55:The
1408:Art
451:doi
117:or
105:or
21:In
2014::
449:.
439:40
437:.
433:.
340:.
327:^
189:,
185:–
1615:)
1611:(
1382:e
1375:t
1368:v
495:e
488:t
481:v
464:.
453::
445::
415:.
384:.
350:.
238:)
48:.
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