scholarly journals Continuous workload control order release revisited: an assessment by simulation

2014 ◽  
Vol 52 (22) ◽  
pp. 6664-6680 ◽  
Author(s):  
Matthias Thürer ◽  
Ting Qu ◽  
Mark Stevenson ◽  
Thomas Maschek ◽  
Moacir Godinho Filho
Author(s):  
Stefan Haeussler ◽  
Philipp Neuner ◽  
Matthias Thürer

AbstractMost Workload Control literature assumes that delivery performance is determined by tardiness related performance measures only. While this may be true for companies that directly deliver to end-customers, for make-to-stock companies or firms that are part of supply chains, producing early often means large inventories in the finished goods warehouse or penalties incurred by companies downstream in the supply chain. Some earlier Workload Control studies used a so-called time limit, which constrains the set of jobs that can be considered for order release, to reduce earliness. However, recent literature largely abandoned the time limit since it negatively impacts tardiness performance. This study revisits the time limit, assessing the use of different adaptive policies that restrict its use to periods of either low or high load. By using a simulation model of a pure job shop, the study shows that an adaptive policy allows to balance the contradictory objectives of delaying the release of orders to reduce earliness and to release orders early to respond to periods of high load as quick as possible. Meanwhile, only using a time limit in periods of high load was found to be the best policy.


2017 ◽  
Vol 194 ◽  
pp. 181-189 ◽  
Author(s):  
Nuno O. Fernandes ◽  
Matthias Thürer ◽  
Cristóvão Silva ◽  
Sílvio Carmo-Silva

2012 ◽  
Vol 21 (5) ◽  
pp. 939-953 ◽  
Author(s):  
Matthias Thürer ◽  
Mark Stevenson ◽  
Cristovao Silva ◽  
Martin J. Land ◽  
Lawrence D. Fredendall

2015 ◽  
Vol 26 (2) ◽  
pp. 280-296 ◽  
Author(s):  
Cristóvão Silva ◽  
Mark Stevenson ◽  
Matthias Thurer

Purpose – Workload control (WLC) is a Production Planning and Control concept of particular relevance to small and medium sized make-to-order companies. Despite the simplicity of its core principles, few successful implementations have been reported, and both understanding and awareness of the concept amongst practitioners is limited. The authors describe a rare successful implementation of WLC in which elements of the concept were embedded in a company to support both customer enquiry management and order release. The purpose of this paper is to focus on the implementation process itself rather than the impact on performance. Design/methodology/approach – A particularly novel aspect of the case is that the implementation was practitioner (rather than researcher) led. A manager chose to read up on and implement the concept, creating a strong in-house commitment to the initiative. The researchers played a facilitating role, e.g. intervening where necessary to answer questions and advise. A factory visit/tour and interview were also conducted post implementation to reflect on the process. Findings – The authors identify the elements of WLC implemented by the practitioner and how they were refined to meet company requirements, with implications for improving the alignment between theory and practice. The paper also informs the implementation process, for example, by highlighting the importance of managerial championing for implementation success and how WLC can be implemented based on a reasonably simple Excel© spreadsheet. Research limitations/implications – More empirical evidence is required to assess the generality of some of the adaptations made by the practitioner; and to collect longitudinal quantitative evidence on the performance of WLC over time. Simulations could also be conducted to confirm the effectiveness of adaptations observed in the study. Practical implications – The case has implications for the process of implementing WLC and may provoke a rethink in terms of the range of companies for which the concept is thought to be appropriate – the case described is of a larger, higher volume company than most previous WLC implementations. Originality/value – A rare case of a successful implementation of WLC at both the customer enquiry management and order release levels; the only practitioner-led implementation of WLC reported in the literature to date.


2020 ◽  
Vol 10 (10) ◽  
pp. 3497
Author(s):  
Paolo Renna

Workload control mechanisms are widely studied in the literature for the control of job-shop systems. The control of these systems involves acceptance, order release and priority dispatching. At the release level, the workload norm controls the “enters” of the jobs; it is relevant how the aggregate workload is computed. Few works have studied new computation methods of the aggregate workload but use the adjusted aggregate workload proposed in the literature. This paper proposes a dynamically adjusted aggregate workload to improve the performance of the workload control mechanism in job-shop systems. The adjusted aggregate workload is updated when each part exits from a workstation; this means that the workload used to release the orders is related to the state of the job shop in real-time. Simulation is used to evaluate and compare the proposed model to the classical models proposed in the literature. The simulation experiments demonstrate improvement of performance and how the model proposed is robust under different manufacturing system conditions.


2019 ◽  
Vol 58 (10) ◽  
pp. 3180-3193 ◽  
Author(s):  
Nuno O. Fernandes ◽  
Matthias Thürer ◽  
Tatiana M. Pinho ◽  
Pedro Torres ◽  
Sílvio Carmo-Silva

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