Tar, József K.Rudas, Imre J.Nádai, LászlóKozłowski, Krzysztof R.Machado, J. A. Tenreiro2014-03-172014-03-172009978-1-84882-984-8978-1-84882-985-50170-8643http://hdl.handle.net/10400.22/4208Though the formal mathematical idea of introducing noninteger order derivatives can be traced from the 17th century in a letter by L’Hospital in which he asked Leibniz what the meaning of D n y if n = 1/2 would be in 1695 [1], it was better outlined only in the 19th century [2, 3, 4]. Due to the lack of clear physical interpretation their first applications in physics appeared only later, in the 20th century, in connection with visco-elastic phenomena [5, 6]. The topic later obtained quite general attention [7, 8, 9], and also found new applications in material science [10], analysis of earth-quake signals [11], control of robots [12], and in the description of diffusion [13], etc.engbook part10.1007/978-1-84882-985-5_10