In this paper we introduce multi-server queueing systems that can be considered as extensions of conventional M/M/s queue to fractional number of servers. We show that the extended Erlang's delay function can be used to calculate delay probabilities for such systems. This approach enables the...

Recently, various environmental problems have been brought with the rapid economic development in China. Therefore, now it is important to enforce optimal environmental policies in order to achieve economic development as well as environmental improvement. In this study, we selected Jiaxing city...