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Input Sequence of Jobs on NEH Algorithm for Permutation Flowshop Scheduling Problem

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Puka R. , Duda J. , Stawowy A.

Management and Production Engineering Review

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2022

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tom Vol. 13, No. 1

32--43

EN

One of the most popular heuristics used to solve the permutation flowshop scheduling problem (PFSP) is the NEH algorithm. The reasons for the NEH popularity are its simplicity, short calculation time, and good-quality approximations of the optimal solution for a wide range of PFSP instances. Since its development, many works have been published analysing various aspects of its performance and proposing its improvements. The NEH algorithm includes, however, one unspecified and unexamined feature that is related to the order of jobs with equal values of total processing time in an initial sequence. We examined this NEH aspect using all instances from Taillard’s and VRF benchmark sets. As presented in this paper, the sorting operation has a significant impact on the results obtained by the NEH algorithm. The reason for this is primarily the input sequence of jobs, but also the sorting algorithm itself. Following this observation, we have proposed two modifications of the original NEH algorithm dealing with sequencing of jobs with equal total processing time. Unfortunately, the simple procedures used did not always give better results than the classical NEH algorithm, which means that the problem of sequencing jobs with equal total processing time needs a smart approach and this is one of the promising directions for further research.

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Profitability of Photovoltaic and Energy Storage System in a Foundry Plant

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Stawowy A. , Wrona R. , Sawczuk M. , Lasek D.

Archives of Foundry Engineering

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2023

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tom Vol. 23, iss. 2

100--105

EN

The article presents a case study on the effectiveness of photovoltaic farm and battery energy storage in one of the Polish foundries. In the study, we consider two investment options: stand-alone PV farm of 1MWp and the farm together with battery energy storage with a maximum capacity of 4MWh. The Payback Period and Net Present Value were used as measures of investment profitability. The paper provides a detailed presentation of the assumptions made, as well as the PV electricity production model of the farm and the optimization model that determines the operation cycle of the energy storage. The case study presented in the article shows that the PV farm is economically sensible and profitable, but the battery energy storage is too costly to give a positive economic effect. Energy storage is an important element that provides flexibility in the energy supply system, so it is necessary to find a technical solution that gives this flexibility. Such a solution could be a virtual power plant, which could include a foundry energy system with a RES installation inside.

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Quick Response Manufacturing for High Mix, Low Volume, High Complexity Manufacturers

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Duda J. , Macioł A. , Jędrusik S. , Rębiasz B. , Stawowy A. , Sopińska-Lenart M.

Management and Production Engineering Review

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2021

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tom Vol. 12, No. 1

72--84

EN

The market of consumer goods requires nowadays quick response to customer needs. As a consequence, this is transferred to the time restrictions that the semi-finished product manufacturer must meet. Therefore the cost of manufacturing cannot determine how production processes are designed, and the main evaluation function of manufacturing processes is the response time to customers’ orders. One of the ideas for implementing this idea is the QRM (Quick Response Manufacturing) production organization system. The purpose of the research undertaken by the authors was to develop an innovative solution in the field of production structure, allowing for the implementation of the QRM concept in a Contract Manufacturer, which realizes its tasks according to engineering-to-order (ETO) system in conditions defined as High Mix, Low Volume, High Complexity. The object of the research was to select appropriate methods for grouping products assuming that certain operations will be carried out in traditional but well-organized technological and/or linear cells. The research was carried out in one of the largest producers of sheet metal components in Europe. Pre-completed groupings for data obtained from the company had indicated that – among the classical methods – the best results had been given by the following methods: King’s Algorithm (otherwise called: Binary Ordering, Rank Order Clustering), k-means, and Kohonen’s neural networks. The results of the tests and preliminary simulations based on the data from the company proved that the implementation of the QRM concept does not have to be associated with the absolute formation of multi-purpose cells. It turned out that the effect of reducing the response time to customer needs can be obtained by using hybrid structures that combine solutions characteristic of cellular systems with traditional systems such as a technological, linear, or mixed structure. However, this requires the application of technological solutions with the highest level of organization.