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A variety of order release mechanisms have been developed for workload control. In this paper the effectiveness of order release mechanisms in a job shop environment is assessed by studying the influence of single order release dimensions, instead of comparing different mechanisms as a whole. In particular, the paper aims at improving the basis for selecting the workload accounting over time and the workload control strategies, through the understanding of its impact on the overall system performance. The robustness of these order release strategies to environmental perturbations is also assessed through a plan of experiments based on the Taguchi method. Simulation results provide important insights for the implementation of order release mechanisms.

POLCA (i.e. Paired-cell Overlapping Loops of Cards with Authorization) is a card-based decision support system for production control, developed to support the adoption of Quick Response Manufacturing. Two variants of POLCA have been proposed in the literature to improve POLCA performance: Load Based POLCA and Generic POLCA. In this paper, we combine these two variants into a single production control system and analyse its performance for different backlog-sequencing rules. The results of a simulation study carried out for a make-to-order flow shop, support the strategy of combining these two POLCA variants and show that capacity-slack backlog sequencing based on corrected aggregate load have the potential for improving performance.

“This is a post-peer-review, pre-copyedit version of an article published in Advances in Intelligent Systems and Computing. The final authenticated version is available online at: https://doi.org/10.1007/978-3-319-56538-5_40"

Lot splitting is an important approach for shops that compete on short delivery times. Similarly, such shops can benefit from load-limiting order release mechanisms that balance workloads and regulate throughput times. Yet few studies have examined the combined effect of lot splitting and load-limiting order release. We use simulation to assess the combined effect of lot splitting and Paired-cell Overlapping Loops of Cards with Authorization (POLCA), an important load-limiting order release mechanism in the context of time-based competition. The experimental design includes different lot sizes, lot transfer policies, and POLCA quanta, i.e. the limit on the size of jobs represented by a single POLCA card. Lot splitting improves performance if lots can proceed independently as this ensures the quick replenishment of queues at downstream stations. However, we find that enforcing the synchronization of all lots that make up a job at every routing step leads to a deterioration in performance. This extends previous research, which appears to have overemphasized the positive effects of lot splitting. Meanwhile, although POLCA cards were originally used to represent lots, we demonstrate that using cards to represent a certain amount of workload can improve percentage tardy performance. This may also have resonance with other card-based solutions, including kanban.

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“This is a pre-print of an article published in Journal of Intelligent Manufacturing. The final authenticated version is available online at Springer http://dx.doi.org/10.1007/s10845-018-1402-2

O Diagnóstico para a Sustentabilidade do Concelho de Castelo Branco tem dois grandes objectivos: - Apresentar um diagnóstico do Concelho, simples e acessível; - Apontar para as Áreas Estratégicas, em que assentará Castelo Branco Agenda XXI, posteriormente validadas pela comunidade/actores locais. Tem como propósito abranger e integrar num mesmo documento uma descrição actual e representativa dos sistemas ambientais, sociais, económicos e institucionais do concelho de Castelo Branco, resultando na identificação das suas potencialidades e fragilidades. Deste modo, obtém-se a definição das oportunidades e ameaças do concelho, de forma a assentar as grandes opções estratégicas do Desenvolvimento Sustentável, através de um modelo – Castelo Branco Agenda XXI. Assim, o Diagnóstico para a Sustentabilidade permite avaliar a realidade concelhia e efectuar uma análise prospectiva, nomeadamente no que respeita à identificação de problemas e oportunidades, em consonância com o já planeado pela CMCB, no sentido do Desenvolvimento Sustentável e da melhoria da qualidade de vida.

Production control in make-to-order must address the companies’ need for short delivery times and on-time deliveries. Several production control systems may be used to meet these needs. This paper presents a simulation study to evaluate the delivery performance of the TKS, GKS and POLCA production control systems, in the context of a make-to-order flexible flow shop. Since TKS is used for make-to-stock manufacturing, an adaptation of it is made to use in make-to-order. Results of a simulation study show that the adapted TKS outperforms POLCA, but performs worse than GKS. The study is a contribution for the alignment of production control theory to the industrial practice.