73 research outputs found

    Constructive solution methodologies to the capacitated newsvendor problem and surrogate extension

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    The newsvendor problem is a single-period stochastic model used to determine the order quantity of perishable product that maximizes/minimizes the profit/cost of the vendor under uncertain demand. The goal is to fmd an initial order quantity that can offset the impact of backlog or shortage caused by mismatch between the procurement amount and uncertain demand. If there are multiple products and substitution between them is feasible, overstocking and understocking can be further reduced and hence, the vendor\u27s overall profit is improved compared to the standard problem. When there are one or more resource constraints, such as budget, volume or weight, it becomes a constrained newsvendor problem. In the past few decades, many researchers have proposed solution methods to solve the newsvendor problem. The literature is first reviewed where the performance of each of existing model is examined and its contribution is reported. To add to these works, it is complemented through developing constructive solution methods and extending the existing published works by introducing the product substitution models which so far has not received sufficient attention despite its importance to supply chain management decisions. To illustrate this dissertation provides an easy-to-use approach that utilizes the known network flow problem or knapsack problem. Then, a polynomial in fashion algorithm is developed to solve it. Extensive numerical experiments are conducted to compare the performance of the proposed method and some existing ones. Results show that the proposed approach though approximates, yet, it simplifies the solution steps without sacrificing accuracy. Further, this dissertation addresses the important arena of product substitute models. These models deal with two perishable products, a primary product and a surrogate one. The primary product yields higher profit than the surrogate. If the demand of the primary exceeds the available quantity and there is excess amount of the surrogate, this excess quantity can be utilized to fulfill the shortage. The objective is to find the optimal lot sizes of both products, that minimize the total cost (alternatively, maximize the profit). Simulation is utilized to validate the developed model. Since the analytical solutions are difficult to obtain, Mathematical software is employed to find the optimal results. Numerical experiments are also conducted to analyze the behavior of the optimal results versus the governing parameters. The results show the contribution of surrogate approach to the overall performance of the policy. From a practical perspective, this dissertation introduces the applications of the proposed models and methods in different industries such as inventory management, grocery retailing, fashion sector and hotel reservation

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

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    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

    An Investigation into Factors Affecting the Chilled Food Industry

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    With the advent of Industry 4.0, many new approaches towards process monitoring, benchmarking and traceability are becoming available, and these techniques have the potential to radically transform the agri-food sector. In particular, the chilled food supply chain (CFSC) contains a number of unique challenges by virtue of it being thought of as a temperature controlled supply chain. Therefore, once the key issues affecting the CFSC have been identified, algorithms can be proposed, which would allow realistic thresholds to be established for managing these problems on the micro, meso and macro scales. Hence, a study is required into factors affecting the CFSC within the scope of Industry 4.0. The study itself has been broken down into four main topics: identifying the key issues within the CFSC; implementing a philosophy of continuous improvement within the CFSC; identifying uncertainty within the CFSC; improving and measuring the performance of the supply chain. However, as a consequence of this study two further topics were added: a discussion of some of the issues surrounding information sharing between retailers and suppliers; some of the wider issues affecting food losses and wastage (FLW) on the micro, meso and macro scales. A hybrid algorithm is developed, which incorporates the analytic hierarchical process (AHP) for qualitative issues and data envelopment analysis (DEA) for quantitative issues. The hybrid algorithm itself is a development of the internal auditing algorithm proposed by Sueyoshi et al (2009), which in turn was developed following corporate scandals such as Tyco, Enron, and WorldCom, which have led to a decline in public trust. However, the advantage of the proposed solution is that all of the key issues within the CFSC identified can be managed from a single computer terminal, whilst the risk of food contamination such as the 2013 horsemeat scandal can be avoided via improved traceability

    On inventory management for products with a stochastic selling season

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    Managing the inventory of products with stochastic selling seasons is a highly challenging and practically relevant problem. However, the literature providing practical insights into the problem and methods to manage it is limited. In this thesis, we present three studies contributing to this literature. In the first study, we show how the parameters of the problem affect the two key inventory decisions of a firm selling this type of products, i.e. inventory quantity and timing. We also asses the effects for the firm of incorrectly considering the uncertainty of demand timing when deciding on its inventory policy. In the second study, we propose a reformulation of the scenario-approximation of the stochastic capacitated lot-sizing problem, based on cumulative demand. Our formulation significantly simplifies the problem of finding an optimal inventory policy in practical settings with demand dependencies, which naturally arise in the seasonal inventory problem considered in this thesis. In the third study, we adapt this newly developed methodology and apply it to analyze a real-world inventory management problem of an agrochemical producer facing a highly seasonal and uncertain – both in terms of quantity and timing – demand for its products

    Synchronizing the Retail Supply Chain

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    Dit proefschrift ontwerpt een retail supply chain, die beter en goedkoper is dan de gangbare. Dit wordt bereikt door de distributie te synchroniseren op de productie¬momenten. Goederen zouden direct uit productie al stroomafwaarts moeten bewegen, van fabrikant naar retailer, tegen lage kosten, in volle pallets en in volle auto’s en in hoeveel¬heden die groot genoeg zijn om de vraag tot het volgende productiemoment te dekken. Door de formules van de "Krantenverkoper" en die van de economische ordergrootte (EOQ) aan te passen aan een multi-echelon divergerend distributienetwerk, kan ook theoretisch worden bewezen dat het stroomafwaarts positioneren van voorraden inderdaad optimaal is en dat de voorraden daardoor zullen dalen. De huidige magazijnen van de leveranciers kunnen worden gereduceerd tot overslagpunten, waar goederen van de verschillende fabrieken van een leverancier worden samengebracht om rijden met vollere vrachtwagens mogelijk maken. Kleinere hoeveelheden kunnen leveranciers beter afleveren bij het dichtstbijzijnde distributiecentrum van een retailer, waarna de retailer zelf het deel met bestemming elders verder vervoert. Tenslotte kan de winkelbevoorrading worden aangepast aan de schapruimte, waardoor de werkwijze in de distributiecentra kan worden gerationaliseerd.Piet van der Vlist (1947) was born in Ouderkerk aan den IJssel. He received his high-school diploma from the Marnix Gymnasium in Rotterdam. Also in Rotterdam he graduated as Electronics Engineer at the University of Applied Sciences. He obtained a Master of Science in Electronics at the Delft University of Technology and one in Management Sciences at the University of Twente. He worked 15 years with the Dutch Ministry of Defense on the design and realization of the first generation digital communications systems. Then he joined Bakkenist Management Consultants and later Deloitte Consultancy, together for over 20 years. As consultant he was involved in numerous projects on Data exchange and Supply Chain redesign. Besides that, he was for 11 years (part-time) professor in ICT and Logistics at the Eindhoven University of Technology. Piet wrote and edited several books on data exchange and published numerous articles in business and scientific journals. A fairly good overview of his scientific career can be found in the "Liber Amicorum" that his friends wrote when he left Eindhoven University1. His current research interests lie in the design and management of retail supply chains, all the way from production down to the shelves. He found that the supply chain with the overall lowest costs requires synchronization of distribution to production and not the other way around as current practice seems to dictate. When he had to quit his jobs for health reasons, he finally found the opportunity to devote his time to research and extend the theory that supports Supply Chain Synchronization. He programmed built to purpose simulation models to get a better insight in the dynamics of synchronized supply chains. He joined both the Rotterdam Erasmus University to work with Professor Jo van Nunen and the Eindhoven University of Technology to work with Professor Ton de Kok. This PhD thesis is the result of that effort.This thesis is a design of a retail supply chain that is better and cheaper than the usual one. This is achieved by synchronizing distribution to production. Right from production goods should move downstream the supply chain at low cost in full pallets and in full truckloads, in quantities large enough to cover the needs till the next production run. By extending both the Newsvendor- and the EOQ-formulae to a multi-echelon divergent network, it can be proved that such forward positioning of inventory indeed is optimal and that overall supply chain inventories will drop. The suppliers’ warehouses become stockless cross docking points, where goods from the supplier’s various sourcing plants are brought together to consolidate them into full truckloads. Whenever suppliers deliver lower volumes, they better bring these goods to the nearest retailer’s facility; thereafter the retailer himself should move these goods onward to the proper destination within the retailer’s network. And finally shop replenishment should be rationalized based on shelf coverage, so as to enhance the retailer’s warehouse operations

    A review of discrete-time optimization models for tactical production planning

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    This is an Accepted Manuscript of an article published in International Journal of Production Research on 27 Mar 2014, available online: http://doi.org/10.1080/00207543.2014.899721[EN] This study presents a review of optimization models for tactical production planning. The objective of this research is to identify streams and future research directions in this field based on the different classification criteria proposed. The major findings indicate that: (1) the most popular production-planning area is master production scheduling with a big-bucket time-type period; (2) most of the considered limited resources correspond to productive resources and, to a lesser extent, to inventory capacities; (3) the consideration of backlogs, set-up times, parallel machines, overtime capacities and network-type multisite configuration stand out in terms of extensions; (4) the most widely used modelling approach is linear/integer/mixed integer linear programming solved with exact algorithms, such as branch-and-bound, in commercial MIP solvers; (5) CPLEX, C and its variants and Lindo/Lingo are the most popular development tools among solvers, programming languages and modelling languages, respectively; (6) most works perform numerical experiments with random created instances, while a small number of works were validated by real-world data from industrial firms, of which the most popular are sawmills, wood and furniture, automobile and semiconductors and electronic devices.This study has been funded by the Universitat Politècnica de València projects: ‘Material Requirement Planning Fourth Generation (MRPIV)’ (Ref. PAID-05-12) and ‘Quantitative Models for the Design of Socially Responsible Supply Chains under Uncertainty Conditions. Application of Solution Strategies based on Hybrid Metaheuristics’ (PAID-06-12).Díaz-Madroñero Boluda, FM.; Mula, J.; Peidro Payá, D. (2014). A review of discrete-time optimization models for tactical production planning. International Journal of Production Research. 52(17):5171-5205. doi:10.1080/00207543.2014.899721S51715205521

    On Risk and Uncertainty in Inventory Problems with Stochastic Nature

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    Sustainable Industrial Engineering along Product-Service Life Cycle/Supply Chain

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    Sustainable industrial engineering addresses the sustainability issue from economic, environmental, and social points of view. Its application fields are the whole value chain and lifecycle of products/services, from the development to the end-of-life stages. This book aims to address many of the challenges faced by industrial organizations and supply chains to become more sustainable through reinventing their processes and practices, by continuously incorporating sustainability guidelines and practices in their decisions, such as circular economy, collaboration with suppliers and customers, using information technologies and systems, tracking their products’ life-cycle, using optimization methods to reduce resource use, and to apply new management paradigms to help mitigate many of the wastes that exist across organizations and supply chains. This book will be of interest to the fast-growing body of academics studying and researching sustainability, as well as to industry managers involved in sustainability management
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