An integrated model for product mix problem and scheduling considering overlapped operations

Product mix problem is one of the most important decisions made in production systems. Several algorithms have been developed to determine the product mix. Most of the previous works assume that all resources can perform, simultaneously and independently, which may lead to infeasibility of the schedule. In this paper, product mix problem and scheduling are considered, simultaneously. A new mixed-integer programming (MIP) model is proposed to formulate this problem. The proposed model differentiates between process batch size and transfer batch size. Therefore, it is possible to have overlapped operations. The numerical example is used to demonstrate the implementation of the proposed model. In addition, the proposed model is examined using some instances previously cited in the literature. The preliminary computational results show that the proposed model can generate higher performance than conventional product mix model

When less is better: insights from the product mix dilemma from the Theory of Constraints perspective

Perhaps due to its origins in a production scheduling software called Optimised Production Technology (OPT), plus the\ud idea of focusing on system constraints, many believe that the Theory of Constraints (TOC) has a vocation for optimal\ud solutions. Those who assess TOC according to this perspective indicate that it guarantees an optimal solution only in\ud certain circumstances. In opposition to this view and founded on a numeric example of a production mix problem, this\ud paper shows, by means of TOC assumptions, why the TOC should not be compared to methods intended to seek optimal\ud or the best solutions, but rather sufficiently good solutions, possible in non-deterministic environments. Moreover, we\ud extend the range of relevant literature on product mix decision by introducing a heuristic based on the uniquely identified\ud work that aims at achieving feasible solutions according to the TOC point of view. The heuristic proposed is tested\ud on 100 production mix problems and the results are compared with the responses obtained with the use of Integer Linear\ud Programming. The results show that the heuristic gives good results on average, but performance falls sharply in some\ud situations

Determinación de la mezcla óptima de productos para una tejeduría textil

Este documento estudia el problema del product-mix en una tejeduría textil. Sobre un modelo general, se definen coeficientes para la producción de textiles llegando a un modelo lineal entero, resuelto por un algoritmo híbrido con solución inicial por método simplex y obtención de la solución entera por un algoritmo genético. Se concluye que deben considerarse restricciones de capacidad, mercado e insumos, que el modelo es linear entero y que el algoritmo propuesto logra soluciones de alta calidad a bajo costo computacional. Futuros trabajos deben explorar otras técnicas de solución y el product-mix textil según la teoría de restricciones (TOC

Determinación de la mezcla óptima de productos para una tejeduría textil

Este documento estudia el problema del product-mix en una tejeduría textil. Sobre un modelo general, se definen coeficientes para la producción de textiles llegando a un modelo lineal entero, resuelto por un algoritmo híbrido con solución inicial por método simplex y obtención de la solución entera por un algoritmo genético. Se concluye que deben considerarse restricciones de capacidad, mercado e insumos, que el modelo es linear entero y que el algoritmo propuesto logra soluciones de alta calidad a bajo costo computacional. Futuros trabajos deben explorar otras técnicas de solución y el product-mix textil según la teoría de restricciones (TOC

A fuzzy optimization approach for procurement transport operational planning in an automobile supply chain

We consider a real-world automobile supply chain in which a first-tier supplier serves an assembler and determines its procurement transport planning for a second-tier supplier by using the automobile assembler's demand information, the available capacity of trucks and inventory levels. The proposed fuzzy multi-objective integer linear programming model (FMOILP) improves the transport planning process for material procurement at the first-tier supplier level, which is subject to product groups composed of items that must be ordered together, order lot sizes, fuzzy aspiration levels for inventory and used trucks and uncertain truck maximum available capacities and minimum percentages of demand in stock. Regarding the defuzzification process, we apply two existing methods based on the weighted average method to convert the FMOILP into a crisp MOILP to then apply two different aggregation functions, which we compare, to transform this crisp MOILP into a single objective MILP model. A sensitivity analysis is included to show the impact of the objectives weight vector on the final solutions. The model, based on the full truck load material pick method, provides the quantity of products and number of containers to be loaded per truck and period. An industrial automobile supply chain case study demonstrates the feasibility of applying the proposed model and the solution methodology to a realistic procurement transport planning problem. The results provide lower stock levels and higher occupation of the trucks used to fulfill both demand and minimum inventory requirements than those obtained by the manual spreadsheet-based method. (C) 2014 Elsevier Inc. All rights reserved.This work has been funded partly by the Spanish Ministry of Science and Technology project: Production technology based on the feedback from production, transport and unload planning and the redesign of warehouses decisions in the supply chain (Ref. DPI2010-19977) and by the Universitat Politecnica de Valencia project 'Material Requirement Planning Fourth Generation (MRPIV) (Ref. PAID-05-12)'.Díaz-Madroñero Boluda, FM.; Peidro Payá, D.; Mula, J. (2014). A fuzzy optimization approach for procurement transport operational planning in an automobile supply chain. Applied Mathematical Modelling. 38(23):5705-5725. https://doi.org/10.1016/j.apm.2014.04.053S57055725382

The Theory Of Constraints And Its Application In A Manufacturing Firm

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2008Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2008Kısıtlar Teorisi (KT), kâr artırmaya odaklanan bir organizasyonel değişim metodudur. Kısıtlar teorisinin başlıca konsepti, her organizasyonun en az bir adet kısıta sahip olmasıdır. Kısıt, organizasyonun uğruna çabaladığı her ne ise – genellikle kârdır- bunu sınırlayan herhangi bir faktördür. Üretim ve servis organizasyonlarının çoğunluğu için amaç, şimdi ve gelecekte yani sürekli ve artarak daha fazla kâr sağlamaktır. Kısıtlar teorisi, organizasyonları bir bütün olarak ele alır, sadece üretim departmanını ya da sadece tek bir fabrikayı ya da fabrikanın bir departmanını değil. Lokal optimumlarla ilgilenilmez. Bu çalışmanın amacı, kısıtlar teorisi yaklaşımını kullanarak ürün karması ve sonuçlarının firma karlılığı üzerindeki etkileri ortaya koyacak bir model kurabilmek ve uygulayabilmektir. Bu çerçevede, pamuk ipliğinden ring iplik üretimi yapan bir firmada tanımlayıcı ve keşifsel olay çalışmaları yapılmıştır. Bu çalışmada, geleneksel maliyet muhasebesi sistemi ile Kısıtlar teorisinin katkı payı muhasebe sistemi karşılaştırılmıştır. Bu nedenle, optimum ürün karmaları ve bu ürün karmalarının firma kârlılıklarının sonuçları karşılaştırılmıştır. Analizler sonucunda görülmüştür ki, Kısıtlar teorisinin katkı payı muhasebe sistemi maksimum kârı sağlayan sistemdir. Buradan yola çıkılarak, tekstil üretiminde ve benzer koşullardaki firmalar için, kısıtlar teorisinin katkı payı muhasebe sistemi kullanılarak daha kârlı ürün karması çözümlerine ulaşılabilir.The Theory of Constraints is an organizational change method that is focused on profit improvement. The essential concept of TOC is that every organization must have at least one constraint. A constraint is any factor that limits the organization from getting more of whatever it strives for, which is usually profit. For most manufacturing and service organizations the goal of the organization is to make a larger profit now and in the future. Theory of Constraints (TOC), accepts the organization as a whole, not the manufacturing department, or one plant, or one department within the plant. Local optimums are not concerned with. The purpose of the research is to provide and apply a model for product mix and the effect of the results to the profitability of the firm by using Theory of Constraint approach. In this frame, descriptive and exploratory case studies had been made in a ring spun cotton yarn manufacturing firm. In this research the traditional cost accounting system and the throughput accounting system of TOC were compared. For this reason, optimum product mixes determined and the results of the profitablities compared. It was seen that the maximum profit was of throughput accounting system. To sum up, the firms which are in textile manufacturing business and have similar conditions, could be achieve more profitable product mix solutions by throughput accounting of TOC.Yüksek LisansM.Sc

Tree-Based Classifier Ensembles for PE Malware Analysis: A Performance Revisit

Given their escalating number and variety, combating malware is becoming increasingly strenuous. Machine learning techniques are often used in the literature to automatically discover the models and patterns behind such challenges and create solutions that can maintain the rapid pace at which malware evolves. This article compares various tree-based ensemble learning methods that have been proposed in the analysis of PE malware. A tree-based ensemble is an unconventional learning paradigm that constructs and combines a collection of base learners (e.g., decision trees), as opposed to the conventional learning paradigm, which aims to construct individual learners from training data. Several tree-based ensemble techniques, such as random forest, XGBoost, CatBoost, GBM, and LightGBM, are taken into consideration and are appraised using different performance measures, such as accuracy, MCC, precision, recall, AUC, and F1. In addition, the experiment includes many public datasets, such as BODMAS, Kaggle, and CIC-MalMem-2022, to demonstrate the generalizability of the classifiers in a variety of contexts. Based on the test findings, all tree-based ensembles performed well, and performance differences between algorithms are not statistically significant, particularly when their respective hyperparameters are appropriately configured. The proposed tree-based ensemble techniques also outperformed other, similar PE malware detectors that have been published in recent years

Application of Optimization in Production, Logistics, Inventory, Supply Chain Management and Block Chain

The evolution of industrial development since the 18th century is now experiencing the fourth industrial revolution. The effect of the development has propagated into almost every sector of the industry. From inventory to the circular economy, the effectiveness of technology has been fruitful for industry. The recent trends in research, with new ideas and methodologies, are included in this book. Several new ideas and business strategies are developed in the area of the supply chain management, logistics, optimization, and forecasting for the improvement of the economy of the society and the environment. The proposed technologies and ideas are either novel or help modify several other new ideas. Different real life problems with different dimensions are discussed in the book so that readers may connect with the recent issues in society and industry. The collection of the articles provides a glimpse into the new research trends in technology, business, and the environment