Funding for this research was provided by:
National Research Foundation of Korea (NRF-2017R1A2B003877)
National Research Foundation of Korea (NRF-2015R1A4A1041675)
Gruppo Nazionale per l’Analisi Matematica, la Probabilità e le loro Applicazioni
Article History
Received: 19 September 2018
Accepted: 2 May 2019
First Online: 7 May 2019