TY - GEN A1 - Brandt, Andreas A1 - Brandt, Manfred T1 - Approximations for the second moments of sojourn times in M/GI systems under state-dependent processor sharing N2 - We consider a system with Poisson arrivals and general service times, where the requests are served according to the State-Dependent Processor Sharing (SDPS) discipline (Cohen's generalized processor sharing discipline), where each request receives a service capacity which depends on the actual number of requests in the system. For this system, denoted by $M/GI/SDPS$, we derive approximations for the squared coefficients of variation of the conditional sojourn time of a request given its service time and of the unconditional sojourn time by means of two-moment fittings of the service times. The approximations are given in terms of the squared coefficients of variation of the conditional and unconditional sojourn time in related $M/D/SDPS$ and $M/M/SDPS$ systems, respectively. The numerical results presented for $M/GI/m-PS$ systems illustrate that the proposed approximations work well. T3 - ZIB-Report - 09-25 KW - state-dependent processor sharing KW - M/GI/m-PS KW - sojourn time KW - moments KW - approximations Y1 - 2009 UR - https://opus4.kobv.de/opus4-zib/frontdoor/index/index/docId/1141 UR - https://nbn-resolving.org/urn:nbn:de:0297-zib-11414 SN - 1438-0064 ER -