| 1. |
- Adamson, Göran, 1958-, et al.
(författare)
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Feature-based Function Block Control Framework for Manufacturing Equipment in Cloud Environments
- 2018
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Ingår i: International Journal of Production Research. - : Taylor & Francis. - 0020-7543 .- 1366-588X. ; 57:12, s. 3954-3974
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Tidskriftsartikel (refereegranskat)abstract
- The ability to adaptively control manufacturing equipment in cloud environments is becoming increasingly more important. Industry 4.0, supported by Cyber Physical Systems and the concept of on-demand, scalable and pay-for-usage resource-sharing in cloud environments offers many promises regarding effective and flexible manufacturing. For implementing the concept of manufacturing services in a cloud environment, a cloud control approach for the sharing and control of networked manufacturing resources is required. This paper presents a cloud service-based control approach which has a product perspective and builds on the combination of event-driven IEC 61499 Function Blocks and product manufacturing features. Distributed control is realised through the use of a networked control structure of such Function Blocks as decision modules, enabling an adaptive run-time behaviour. The control approach has been developed and implemented as prototype systems for both local and distributed manufacturing scenarios, in both real and virtual applications. An application scenario is presented to demonstrate the applicability of the control approach. In this scenario, Assembly Feature-Function Blocks for adaptive control of robotic assembly tasks have been used.
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| 2. |
- Agrawal, Tarun Kumar, et al.
(författare)
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Demonstration of a blockchain-based framework using smart contracts for supply chain collaboration
- 2023
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 61:5, s. 1497-1516
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Tidskriftsartikel (refereegranskat)abstract
- Blockchain technologies can support traceability, transparency and trust among participants. This has primarily been explored in established supply chains and not in the growing use of business networks or ecosystems, which is a notable limitation since supply chains typically are organised with a dominant actor that ensures common information systems and standards that negate blockchain benefits. Hence, this study explores the design of a blockchain-based collaborative framework for resource sharing using smart contracts. These are particularly well-suited for supporting operations in broader networks or ecosystems beyond supply chains with established collaborations and hierarchies. Based on a systematic literature review, a demonstrator framework was developed for stakeholder interactions through a procurement and distribution unit backed with blockchain technology. The framework consists of (a) network architecture to demonstrate partner interactions; (b) rules for network working principles based on supply collaboration requirements; (c) UML diagram to define smart contract interaction sequence; and (d) algorithm for smart contract network verification and validation. Applicability of these smart contracts was verified by deployment on an Ethereum blockchain. The demonstrator framework ensures quality and data authenticity in supply networks, so it is useful for effective resource utilisation in networks where outsourcing and production surpluses are major issues.
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| 3. |
- Agrawal, Tarun, 1989, et al.
(författare)
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Supply chain visibility: A Delphi study on managerial perspectives and priorities
- 2022
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 62:8, s. 2927-2942
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Tidskriftsartikel (refereegranskat)abstract
- Visibility across supply chains has been a key concern for organisations for many years, but the tools and information systems to achieve real-time visibility have not been available until recently. In response to uncertainty and complexity, advanced information and communication technologies have been explored for supply chain visibility (SCV). However, managerial perspectives are largely absent from the current literature. In response, this paper systematically documents managerial factors influencing SCV and information that should be collected and shared among supply chain partners for better visibility. A multi-stage Delphi analysis was conducted with 26 supply chain experts from various globally recognised enterprises with manufacturing units located worldwide. The results provide details on prioritised managerial perspectives and experiences within (1) factors affecting SCV (drivers, enablers, challenges and contingencies), (2) SCV content (supplier, internal and customer information) and (3) implications of SCV (capabilities and performance effects). One observation was that forecasting is not deemed as important due to severe disruptions in supply chains. Real-time visibility for better predictability emerged as the top priority. This study is among the few that empirically explores factors influencing supply chain visibility and generates new insights into why barriers can be difficult to overcome in complex supply chain settings.
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| 4. |
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| 5. |
- Amouzgar, Kaveh, 1980-, et al.
(författare)
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Multi-objective optimisation of tool indexing problem : a mathematical model and a modified genetic algorithm
- 2021
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Ingår i: International Journal of Production Research. - : Taylor & Francis Group. - 0020-7543 .- 1366-588X. ; 59:12, s. 3572-3590
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Tidskriftsartikel (refereegranskat)abstract
- Machining process efficiencies can be improved by minimising the non-machining time, thereby resulting in short operation cycles. In automatic-machining centres, this is realised via optimum cutting tool allocation on turret-magazine indices – the “tool-indexing problem”. Extant literature simplifies TIP as a single-objective optimisation problem by considering minimisation of only the tool-indexing time. In contrast, this study aims to address the multi-objective optimisation tool indexing problem (MOOTIP) by identifying changes that must be made to current industrial settings as an additional objective. Furthermore, tool duplicates and lifespan have been considered. In addition, a novel mathematical model is proposed for solving MOOTIP. Given the complexity of the problem, the authors suggest the use of a modified strength Pareto evolutionary algorithm combined with a customised environment-selection mechanism. The proposed approach attained a uniform distribution of solutions to realise the above objectives. Additionally, a customised solution representation was developed along with corresponding genetic operators to ensure the feasibility of solutions obtained. Results obtained in this study demonstrate the realization of not only a significant (70%) reduction in non-machining time but also a set of tradeoff solutions for decision makers to manage their tools more efficiently compared to current practices.
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| 6. |
- Angelis, Jannis, et al.
(författare)
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Product service transitions in reverse
- 2017
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Ingår i: International Journal of Production Research. - 0020-7543 .- 1366-588X.
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Tidskriftsartikel (refereegranskat)
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| 7. |
- Axsäter, Sven
(författare)
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A Capacity Constrained Production-Inventory System with Stochastic Demand and Production Times
- 2010
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 48:20, s. 6203-6209
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Tidskriftsartikel (refereegranskat)abstract
- This paper considers a simple model of a capacity constrained production-inventory system with Poisson demand. The system is controlled by an S policy. The production time for a unit is modelled as a gamma distributed stochastic variable. Using M/G/1 queuing theory it is very easy to evaluate holding and backorder costs and optimise the ordering policy. The suggested model may be useful when evaluating investments in production.
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| 8. |
- Axsäter, Sven, et al.
(författare)
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Combining items for lot sizing in multi-level assembly systems
- 1987
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 25:6, s. 795-807
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Tidskriftsartikel (refereegranskat)abstract
- Many manufacturing firms are faced with the problem of planning the production/purchase quantities for items in single product, multi-level assembly production/inventory systems. Such systems are characterized by a single product, or end item, used to satisfy customer demand, which is assembled from a number of component items which, in turn, may be assembled from one or more other component items, etc. Component items may be either fabricated or purchased. This paper identifies conditions on the cost parameters which, when applicable, allow items to be combined for purpose of optimization, thereby reducing the size of the problem.
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| 9. |
- Axsäter, Sven
(författare)
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Evaluation of lot-sizing techniques
- 1986
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 24:1, s. 51-57
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Tidskriftsartikel (refereegranskat)abstract
- Standard lot-sizing models are often not directly applicable in practice. Different assumptions in lot-sizing models and the extent to which these assumptions are valid in various practical situations are discussed. Practitioners also tend to prefer simple standard methods even for complex problems, which means that adjustment of the lot sizes may be desirable. The ways in which such adjustments can be carried out are analyzed.
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| 10. |
- Berling, Peter, 1973-, et al.
(författare)
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Multi-echelon inventory control : an adjusted normal demand model for implementation in practice
- 2014
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Ingår i: International Journal of Production Research. - : Informa UK Limited. - 0020-7543 .- 1366-588X. ; 52:11, s. 3331-3347
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an approximation model for coordinated control of one-warehouse multiple-retailer inventory systems, where all locations use continuous review (R, nQ) policies. The motivation stems from close collaboration with a supply chain management software company, Syncron International, and one of their customers. A core objective has been to develop an accurate method for determining near-optimal reorder points that can be directly applied to real-life systems. The approach is based on decomposing the complex multi-echelon problem into N + 1 single-echelon problems, using a near-optimal-induced backorder cost at the central warehouse. Important extensions made compared to earlier work include the addition of procedures to adjust for lead-time variability, and for undershooting the reorder point when customers’ order sizes vary. The result is a flexible model that is computationally and conceptually simple enough to be implemented in practice. A numerical study, including real data from the case company, illustrates that the new model outperforms existing methods in the literature. Compared to the current methods used by the case company, it offers significant improvements in both service-level fulfilment and system-wide inventory holding costs. Implementations of the model into the Syncron software are in progress.
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