TY - CHAP AU - Tóth, Ádám AU - Sztrik, János AU - Bardavelidze, Avtandil ED - Dudin, Alexander ED - Nazarov, Anatoly ED - Moiseev, Alexander TI - Simulating Retrial Queues with Finite Source, Two-Way Communication to the Orbit, Backup Server, and Impatient Customers T2 - Information Technologies and Mathematical Modelling. Queueing Theory and Applications PB - Springer Nature Switzerland CY - Cham SN - 9783031653858 T3 - Communications in Computer and Information Science, ISSN 1865-0929 ; 2163. PY - 2024 SP - 316 EP - 328 PG - 13 DO - 10.1007/978-3-031-65385-8_23 UR - https://m2.mtmt.hu/api/publication/35181820 ID - 35181820 LA - English DB - MTMT ER - TY - CHAP AU - Tóth, Ádám AU - Sztrik, János ED - Kozyrev, Dmitry V. ED - Samouylov, Konstantin E. ED - Vishnevskiy, Vladimir M. TI - The Simulation of Finite-Source Retrial Queues with Two-Way Communication to the Orbit, Incorporating a Backup Server T2 - Distributed Computer and Communication Networks: Control, Computation, Communications PB - Springer Nature Switzerland CY - Cham SN - 9783031504822 T3 - Lecture Notes in Computer Science, ISSN 0302-9743 ; 14123. PY - 2024 SP - 44 EP - 55 PG - 12 DO - 10.1007/978-3-031-50482-2_4 UR - https://m2.mtmt.hu/api/publication/34758809 ID - 34758809 LA - English DB - MTMT ER - TY - JOUR AU - Melikov, Agassi AU - Poladova, Laman AU - Sztrik, János TI - Queuing-Inventory System with Catastrophes in the Warehouse: Case of Rare Catastrophes JF - MATHEMATICS J2 - MATHEMATICS-BASEL VL - 12 PY - 2024 IS - 6 SP - 906 SN - 2227-7390 DO - 10.3390/math12060906 UR - https://m2.mtmt.hu/api/publication/34748505 ID - 34748505 AB - A model of a single-server queuing-inventory system (QIS) with a limited waiting buffer for consumer customers (c-customers) and catastrophes has been developed. When a catastrophe occurs, all items in the system’s warehouse are destroyed, but c-customers in the system are still waiting for replenishment. In addition to c-customers, negative customers (n-customers) are also taken into account, each of which displaces one c-customer (if any). The policy (s, S) is used to replenish stocks. If, when a customer enters, the system warehouse is empty, then, according to Bernoulli’s trials, this customer either leaves the system without goods or joins the buffer. The mathematical model of the investigated QIS is constructed in the form of a continuous-time Markov chain (CTMC). Both exact and approximate methods for calculating the steady-state probabilities of constructed CTMCs are proposed and closed-form expressions are obtained for calculating the performance measures. Numerical evaluations are presented, demonstrating the high accuracy of the developed approximate formulas, as well as the behavior of performance measures depending on the input parameters. In addition, an optimization problem is solved to obtain the optimal value of the reorder point to minimize the expected total cost. LA - English DB - MTMT ER - TY - JOUR AU - Tóth, Ádám AU - Sztrik, János TI - Simulation of two-way communication retrial queueing systems with unreliable server and impatient customers in the orbit JF - Stochastic Modeling and Applied Research of Technology J2 - Stochastic Modeling and Applied Research of Technology VL - 3 PY - 2023 SP - 45 EP - 50 PG - 6 SN - 2782-4705 UR - https://m2.mtmt.hu/api/publication/34748999 ID - 34748999 LA - English DB - MTMT ER - TY - CONF AU - Tóth, Ádám AU - Sztrik, János AU - A., Bradvelidze ED - S. P., Moiseeva ED - D. V., Semenova ED - S. V., Shidlovsky ED - E. A., Fedorova ED - D. V., Shashev ED - O. D., Lizyura TI - Simulating retrial queues with a finite source, two-way communication to the orbit, the inclusion of a backup server and impatient customers T2 - Proceedings of the 22th International Conference named after A.F. Terpugov, Informational Technologies and Mathematical Modelling ITMM-2023 Part 1. PY - 2023 SP - 59 EP - 64 PG - 6 UR - https://m2.mtmt.hu/api/publication/34446612 ID - 34446612 LA - English DB - MTMT ER - TY - JOUR AU - Ozkar, Serife AU - Melikov, Agassi AU - Sztrik, János TI - Queueing-Inventory Systems with Catastrophes under Various Replenishment Policies JF - MATHEMATICS J2 - MATHEMATICS-BASEL VL - 11 PY - 2023 IS - 23 SP - 1 EP - 24 PG - 24 SN - 2227-7390 DO - 10.3390/math11234854 UR - https://m2.mtmt.hu/api/publication/34412202 ID - 34412202 AB - We discuss two queueing-inventory systems with catastrophes in the warehouse. Catastrophes occur according to the Poisson process and instantly destroy all items in the inventory. The arrivals of the consumer customers follow a Markovian arrival process and they can be queued in an infinite buffer. The service time of a consumer customer follows a phase-type distribution. The system receives negative customers which have Poisson flows and as soon as a negative customer comes into the system, he causes a consumer customer to leave the system, if any. One of two inventory policies is used in the systems: either (s,S) or (s,Q). If the inventory level is zero when a consumer customer arrives, then this customer is either lost (lost sale) or joins the queue (backorder sale). The system is formulated by a four-dimensional continuous-time Markov chain. Ergodicity condition for both systems is established and steady-state distribution is obtained using the matrix-geometric method. By numerical studies, the influence of the distributions of the arrival process and the service time and the system parameters on performance measures are deeply analyzed. Finally, an optimization study is presented in which the criterion is the minimization of expected total costs and the controlled parameter is warehouse capacity. LA - English DB - MTMT ER - TY - JOUR AU - Tóth, Ádám AU - Sztrik, János TI - Analysis of retrial queueing systems with two-way communication and impatient customers using simulation JF - ANNALES MATHEMATICAE ET INFORMATICAE J2 - ANN MATH INFORM VL - 58 PY - 2023 SP - 160 EP - 169 PG - 10 SN - 1787-5021 DO - 10.33039/ami.2023.08.015 UR - https://m2.mtmt.hu/api/publication/34397930 ID - 34397930 LA - English DB - MTMT ER - TY - JOUR AU - Jeganathan, Kathirvel AU - Harikrishnan, Thanushkodi AU - Lakshmanan, Kumarasankaralingam AU - Melikov, Agassi AU - Sztrik, János TI - Modeling of Junior Servers Approaching a Senior Server in the Retrial Queuing-Inventory System JF - MATHEMATICS J2 - MATHEMATICS-BASEL VL - 11 PY - 2023 IS - 22 SP - 1 EP - 31 PG - 31 SN - 2227-7390 DO - 10.3390/math11224581 UR - https://m2.mtmt.hu/api/publication/34281828 ID - 34281828 AB - This article deals with the queuing-inventory system, composed of c junior servers, a senior server, two finite waiting halls, and an infinite orbit. On occasion, junior servers encounter challenges during customer service. In these instances, they approach the senior server for guidance in resolving the issue. Suppose the senior server is engaged with another junior server. The approaching junior servers await their turn in a finite waiting area with a capacity of c for consultation. Concerning this, we study the performance of junior servers approaching the senior server in the retrial queuing-inventory model with the two finite waiting halls dedicated to the primary customers and the junior servers for consultation. We formulate a level-dependent QBD process and solve its steady-state probability vector using Neuts and Rao’s truncation method. The stability condition of the system is derived and the R matrix is computed. The optimum total cost has been obtained, and the sensitivity analyses, which include the expected total cost, the waiting time of customers in the waiting hall and orbit, the number of busy servers, and a fraction of the successful retrial rate of the model, are computed numerically. LA - English DB - MTMT ER - TY - GEN AU - Sztrik, János TI - Teaching Queueing Theory Based on Digital Technologies PY - 2023 UR - https://m2.mtmt.hu/api/publication/34196192 ID - 34196192 LA - English DB - MTMT ER - TY - GEN AU - Sztrik, János AU - Tóth, Ádám TI - The simulation of finite-source retrial queues with two-way communication to the orbit using a backup server PY - 2023 UR - https://m2.mtmt.hu/api/publication/34161084 ID - 34161084 LA - English DB - MTMT ER -