Browsing by Author "Karakutuk, S. Serhat"

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Citation - WoS: 6
Citation - Scopus: 8
A goal programming approach to lean production system implementation
(Taylor and Francis Ltd., 2023) Sadik Serhat Karakütük; Mustafa Arslan Ornek; Ornek, M. Arslan; Karakutuk, S. Serhat
Companies use different production policies to ensure customer demands are satisfied in time. To track the performance of production policies some important Key Performance Indicators related to production control and management are On-Time Delivery (OTD) machine or line productivity (OEE–Overall Equipment Efficiency) optimization of inventory levels between workstations (WIP) customer satisfaction i.e. prioritization of customer orders according to requirements of the customer and backlog minimization. In this study a real-life production management problem is described modelled and solved to improve customer delivery rate and to plan manufacturing orders using lean production tools. Currently the Make-to-Stock policy is used for semi-finished materials. The problems encountered are low customer service level high level of WIP between operations and efficiency losses. Therefore the goal of this study is to increase efficiency (OTD OEE and customer satisfaction) by minimizing setup time decreasing WIP by minimizing earliness backlog quantity level and improving service level by minimizing lateness of orders. Since these goals contradict each other we propose a multi-objective mathematical formulation with a setup carryover strategy. Then we formulate a Goal Programming (GP) model and solve it by using different GP variants and the normalization method. Finally we discuss numerical results and provide our final remarks and conclusions. © 2023 Elsevier B.V. All rights reserved.
Citation - WoS: 7
Citation - Scopus: 9
An application of a circular economy approach to design an energy-efficient heat recovery system
(ELSEVIER SCI LTD, 2021) S. Serhat Karakutuk; Sener Akpinar; M. Arslan Ornek; Akpinar, Sener; Ornek, M. Arslan; Karakutuk, S. Serhat
This paper aims to develop an optimal real-life energy-efficient design for a production plant within the concept of the circular economy. The problem is to install a Heat Recovery System (HRS) that utilizes the hot oil used by the compressors to heat the water for the central heating system. To achieve the desired level of energy efficiency this design problem must be formulated from both the optimization and sustainability points of view. Additionally this design problem must also consider the investment cost. In line with this purpose this paper formulates this design problem as an optimization problem employing a mathematical programming approach as a single objective and as a multi-objective optimization problem through a goal programming approach. Besides this paper uses the return on investment as a key performance indicator since it deals with a real-life design problem with an investment cost. The related design problem is solved with the single objective and multiobjective versions of the developed mathematical programming model via a commercial solver to identify different design alternatives and hence giving the decision-maker to make a selection option. Finally the capability of the developed mathematical programming model is tested on a set of randomly generated problems. The obtained results indicate that the developed mathematical programming model is a successful decision support system since its single and multi-objective versions are capable of identifying energy-efficient production designs within the context of the real-life problem on hand and the circular economy.