121 citations · 155 across the 7 of their papers we have counts for
7 papers
Exponential single server queues in an interactive random environment
Sonja Otten, Ruslan Krenzler, Hans Daduna +1
We consider exponential single server queues with state-dependent arrival and service rates which evolve under influences of external environments. The transitions of the queues ar…
Lost-customers approximation of semi-open queueing networks with backordering -- An application to minimise the number of robots in robotic mobile fulfilment systems
Sonja Otten, Ruslan Krenzler, Lin Xie +2
We consider a semi-open queueing network (SOQN), where a customer requires exactly one resource from the resource pool for service. If there is a resource available, the customer i…
Efficient order picking methods in robotic mobile fulfillment systems
Lin Xie, Nils Thieme, Ruslan Krenzler +1
Robotic mobile fulfillment systems (RMFSs) are a new type of warehousing system, which has received more attention recently, due to increasing growth in the e-commerce sector. Inst…
Deterministic Pod Repositioning Problem in Robotic Mobile Fulfillment Systems
Ruslan Krenzler, Lin Xie, Hanyi Li
In a robotic mobile fulfillment system, robots bring shelves, called pods, with storage items from the storage area to pick stations. At every pick station there is a person -- the…
Heuristic Approximations for Closed Networks: A Case Study in Open-pit Mining
Hans Daduna, Ruslan Krenzler, Robert Ritter +1
We investigate a fundamental model from open-pit mining, which is a cyclic system consisting of a shovel, traveling loaded, unloading facility, and traveling back empty. The intera…
Randomization for Markov chains with applications to networks in a random environment
Ruslan Krenzler, Hans Daduna, Sonja Otten
We develop randomized modifications of Markov chains and apply these modifications to the routing chains of customers in Jacksonian stochastic networks. The aim of our investigatio…
Loss systems in a random environment
Ruslan Krenzler, Hans Daduna
We consider a single server system with infinite waiting room in a random environment. The service system and the environment interact in both directions. Whenever the environment…