Browsing by Author "Hoser, Deniz"

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Citation - WoS: 36
Citation - Scopus: 54
A discrete cross aisle design model for order-picking warehouses
(ELSEVIER SCIENCE BV, 2019) Deniz Hoser; Omer Ozturkoglu; Hoser, Deniz; Ozturkoglu, Omer
In this paper we develop new warehouse designs that provide a reduction in travel distance for the order-picking operation which is the most costly operation and the one most closely associated with order delivery time. For this purpose we propose a new layout problem called discrete cross aisle warehouse design. In this problem a linear middle cross aisle is divided into segments called tunnels on each picking aisle. In order to calculate average tour length for the proposed design problem we develop an efficient algorithm that solves the order-picking problem optimally. A harmony search algorithm is used to find optimal tunnel positions that minimize the average tour length under a randomized storage policy by searching the space of all possible designs. A numerical study shows that for small size order lists the best-found solutions have similar layouts to the traditional two-block designs. As the number of locations to be visited increases tunnel positions move away from the center of the warehouse and construct a segregated tunnels on the layout. Compared to the traditional two-block layouts new tunnel based designs provide savings of up to 7% average savings in order-picking tour length. (C) 2018 Elsevier B.V. All rights reserved.
A Polynomial Time Tour Algorithm for Order Picking Operations in Warehouses and New Aisle Designs
(IEOM Society ieom-society@iieom.org, 2017) Ömer Öztürkoǧlu; Deniz Hoşer; Hoser, Deniz; Öztürkoglu, Ömer
In this paper we aim to develop a new innovative warehouse design that provides savings for order picking operation which is the most costly and the most related operations with the order delivery time in warehouses. For this purpose we propose a Discrete Cross Aisle Warehouse Design layout as an alternative to traditional 2-block warehouse layout. In this proposed layout linear middle cross aisle is designed as a discrete structure (one tunnel on each pick aisle). Harmony search algorithm is used to find an optimal tunnel positions that minimize the average tour length under randomized storage policy by searching the space of all possible designs. In order to calculate average tour length on a proposed design an algorithm that solves order picking problem optimally in polynomial time is presented. Computational experiments show that optimum designs have the same layout with the traditional 2-block design for small size order lists. As the number of locations to be visited increases we propose new tunnel allocations that present up to 5% less travel than that in 2-block traditional layout. Warehouse design order picking tour algorithm and randomized storage. © 2017 Elsevier B.V. All rights reserved.
Citation - WoS: 6
Citation - Scopus: 8
An Evaluation of Order-picking Tour Efficiency in Two-block Warehouses
(OSCM FORUM, 2019) Omer Ozturkoglu; Deniz Hoser; Hoser, Deniz; Ozturkoglu, Omer
This study investigates the effects of critical operational and strategical decisions in order-picking warehouses on order pickers' tour lengths. For this study one of the most-commonly applied layouts in practice called two-block layout with a central cross aisle was considered. A full factorial experimental design and multiple-comparisons (Bonferroni t-tests) were applied to statistically determine the significance of various levels of storage policies pick-list sizes warehouse shape ratios warehouse sizes and their all interactions on average tour length. The analysis showed that deeper storage areas were superior to wider areas in small- and medium-sized warehouses. Warehouse designs with a 1: 1 width-to-depth shape ratio offered the most robust layouts. Within-storage aisle policy significantly reduced order-picking tour length and generally outperformed other storage policies.