Industrial Engineering

Permanent URI for this collectionhttps://hdl.handle.net/10679/45

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Browsing by Institution Author "ÖNAL, Mehmet"

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    Economic lot sizing problem with inventory dependent demand
    (Springer Nature, 2020-11) Önal, Mehmet; Albey, Erinç; Industrial Engineering; ÖNAL, Mehmet; ALBEY, Erinç
    We consider an economic lot sizing problem where the demand in a period is a piecewise linear and concave function of the amount of the available inventory after production in that period. We show that the problem isNPhard even when the production capacities are time invariant, and propose a polynomial time algorithm to the case where there are no capacity restrictions on production.
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    Economic lot sizing problem with tank scheduling
    (Elsevier, 2023-07-01) Önal, Mehmet; van den Heuvel, W.; Dereli, Meryem Merve; Albey, Erinç; Industrial Engineering; ÖNAL, Mehmet; ALBEY, Erinç; Dereli, Meryem Merve
    We introduce a multiple-item economic lot sizing problem where items are produced through the fermentation of some raw materials. Fermentation takes place in specialized tanks that have finite capacities, and duration of the fermentation process is item dependent. When fermentation starts, the tanks are not available for the duration of the fermentation process. We analyze the complexity of this problem under various assumptions on the number of items and tanks. In particular, we show that several cases of the problem are (strongly) NP-hard, and we propose polynomial time algorithms to some single item cases. In addition, we propose a quick and simple heuristic approach for one of the multiple item cases.
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    An EOQ model with deteriorating items and self-selection constraints
    (Springer Nature, 2020-09) Önal, Mehmet; Kundakcıoğlu, Ömer Erhun; Industrial Engineering; KUNDAKCIOĞLU, Ömer Erhun; ÖNAL, Mehmet
    In this paper, we consider a store that sells two vertically differentiated items that might substitute each other. These items do not only differ in quality and price, but they also target two different customer segments. Items deteriorate over time and might require price adjustments to avoidcannibalization. We provide closed-form solutions for pricing and ordering of these items that lead to key managerial insights.