Browsing by Author "Özkar, Şerife"
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Analysis of a production inventory system with MAP arrivals, phase-type services and vacation to production facility
Özkar, Şerife (2023)In this paper, we discuss a production inventory system with service times. Customers arrive in the system according to a Markovian arrival process. The service times follow a phase-type distribution. We assume that there ... -
Analysis of a stochastic model for crowdsourcing using map arrivals and phase type services
Chakravarthy, S. R.; Özkar, Şerife (Ministry Communications & High Technologies Republic Azerbai, 2021)In this paper, we model crowdsourcing using MAP for Type 1 arrivals who may opt to serve the other (Poisson type) arrivals. Such models are useful in service sectors wherein one type of customers visit the store to buy ... -
Analysis of M/M/c retrial queue with thresholds, PH distribution of retrial times and unreliable servers
Chakravarthy, Srinivas R.; Özkar, Şerife; Shruti (Korean Soc Computational & Applied Mathematics-KSCAM, 2021)This paper treats a retrial queue with phase type retrial times and a threshold type-policy, where each server is subject to breakdowns and repairs. Upon a server failure, the customer whose service gets interrupted will ... -
Bir gıda dağıtım şirketine ait araç rotalama probleminin kesin ve sezgisel yöntemler ile çözümü
Tok, Nurhayat (Balıkesir Üniversitesi Sosyal Bilimler Enstitüsü, 2021)Günümüzde işletmeler için bir zorunluluk haline gelen rekabet avantajı sağlayabilmenin yolu, önce maliyet avantajı sağlamaktan geçmektedir. Bu çalışmada, fiziksel dağıtım maliyetleri içerisinde yer alan taşıma maliyetlerinin ... -
A MAP|PH|1 production inventory model
Özkar, Şerife (2023)In this study, a production inventory model with phase type service times where customers join the system occur according to a Markovian arrival process is discussed. When the inventory level is positive, if an arriving ... -
A production queueing-inventory system with two-customer and a server subject to breakdown
Koçer, Umay Zeynep Uzunoğlu; Özkar, Şerife (Springer, 2023)A queueing-inventory system where the server is subject to breakdown is examined. The products in inventory are provided by production. Two different types of customers are considered. Each customer type arrives in the ... -
Queueing-inventory systems with catastrophes under various replenishment policies
Özkar, Şerife; Melikov, Agassi; Sztrik, Janos (MDPI, 2023)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 ... -
Two-commodity queueing-inventory system with phase-type distribution of service times
Özkar, Şerife (Springer, 2022)A two-commodity queueing-inventory system with phase-type service times and exponential lead times is considered. There are two types of customers; Type 1 and Type 2. Demands from each customer type occur independently ... -
Two-commodity queueing-inventory system with two classes of customers
Özkar, Şerife; Koçer, Umay Uzunoğlu (Springer India, 2020)We analyze a two-commodity queueing-inventory system with an individual ordering policy. The maximum storage capacity for the ith commodity is S-i (i = 1, 2). The reorder level for ith commodity is fixed as s(i) and whenever ...
