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Manufacturing facilities have traditionally been organized by process or function (with each cell having workstations of a particular process) or by product (with cells specialized for one or more jobs). This paper develops a new fractal alternative for manufacturing job shops which allocates the total number of workstations for most processes equally across several fractal cells. One result is enormous flexibility because each cell can produce nearly every product. The number of workstations required also approaches the minimum found with function organizations because stations are not dedicated to a product or group. Still, the spatial distribution of workstations for different processes that results from placing some in each cell keeps travel and material handling burdens in fractal designs nearly as low as those of product organizations. This paper introduces fractal organization of job shops and looks at it in-depth from a production systems design perspective, placing an emphasis on identifying the advantages of the fractal organization. It also briefly discusses the process of implementing fractal designs, and illustrates an application to job shops with a case example. [ABSTRACT FROM AUTHOR]

This paper presents a multi-period multi-objective distributionally robust optimization framework for enhancing the resilience of personal protective equipment (PPE) supply chains against disruptions caused by pandemics. The research is motivated by and addresses the supply chain challenges encountered by a Canadian provincial healthcare provider during the COVID-19 pandemic. Supply, price, and demand of PPE are the uncertain parameters. The ∊ -constraint method is implemented to generate efficient solutions along the trade-off between cost minimization and service level maximization. Decision makers can easily adjust model conservatism through the ambiguity set size parameter. Experiments investigate the effects of model conservatism on optimal procurement decisions such as the portion of the supply base dedicated to long-term fixed contracts. Other types of PPE sources considered by the model are one-time open-market purchases and federal emergency PPE stockpiles. The study recommends that during pandemics health care providers use distributionally robust optimization with the ambiguity set size falling in one of three intervals based on decision makers' relative preferences for average cost performance, worst-case cost performance, or cost variance. The study also highlights the importance of surveillance and early warning systems to allow supply chain decision makers to trigger contingency plans such as locking contracts, reinforcing logistical capacities and drawing from emergency stockpiles. These emergency stockpiles are shown to play efficient hedging functions in allowing healthcare supply chain decision makers to compensate variations in deliveries from contract and open-market suppliers., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 Elsevier Ltd. All rights reserved.)