83 research outputs found

    Card-based delivery date promising in high-variety manufacturing with order release control

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    Card-based systems – like Kanban and Constant Work-in-Process (ConWIP) – can be simple yet effective means of controlling production. Existing systems, however, can be criticized for their limited applicability and scope. First, card-based systems have not been successful in the production environments that are arguably most in need of their help: complex job shops that produce low-volume, high-variety products. Second, while most existing systems simplify shop floor control, other planning tasks – such as the estimation of short, feasible due dates during customer enquiry management – are not supported. To overcome these limitations, a card-based version of Workload Control – known as COBACABANA (COntrol of BAlance by CArd-BAsed Navigation) – was recently proposed that uses cards for both due date estimation and order release control. This unique combination makes COBACABANA a potentially important means of controlling production, particularly for small job shops with limited resources. However, the original approach had several shortcomings. This paper refines the due date estimation procedure of COBACABANA to make it more practical and consistent with the order release method applied. It then uses simulation to demonstrate – for the first time – the potential of COBACABANA as an integrated concept that combines customer enquiry management and order release control to improve job shop performance. Results also suggest that the need for processing time estimations can be simplified, further facilitating the implementation of COBACABANA in practice

    1kHz 2D silicon retina motion sensor platform

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    This paper proposes an optical motion sensor aimed towards small robotic platforms. It incorporates a 20×20 pixel continuous-time CMOS silicon retina vision sensor with pixels that have local gain control and adapt to background lighting and a DSP microcontroller which computes the global optical flow from the sampled sensor output. The system allows the user to validate various motion algorithms suitable for the platform. Measurements are presented that show that the system can compute global 2D translational motion from complex natural scenes using the image interpolation algorithm at a sample rate of 1 kHz and for speeds up to ±1000 pixels/s using <;5k instruction cycles per frame

    Is lean a theory? Viewpoints and outlook

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    Purpose: Lean remains popular in a wide range of private and public sectors and continues to attract a significant amount of research. However, most of this research is not grounded in theory. This paper presents and discusses different expert viewpoints on the role of theory in lean research and practice and provides guidelines for future research. Design/methodology/approach: Seven experienced lean authors independently provide their views to the question “is Lean a theory?” before Rachna Shah summarizes the viewpoints and provides a holistic outlook for lean research. Findings: Authors agree, disagree and sometimes agree to disagree. However, a close look reveals agreement on several key points. The paper concludes that Lean is not a theory but has plenty of theoretical underpinnings. Many lean-related theories provide promising opportunities for future research. Originality/value: As researchers, we are asked to justify our research drawing on “theory,” but what does that mean for a practice-driven phenomenon such as lean? This paper provides answers and directions for future research

    Proposal of a Reconfigurability Index Using Analytic Network Process

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    This paper proposes a reconfigurability index. Its development is based on five core characteristics, namely modularity, integrability, diagnosability, adaptability and customization. The index takes into consideration the interdependencies that may exist among them. The analytic network process (ANP) method is used to attribute importance weights to each core characteristic. This index can be very useful in practice since it can guide manufacturing companies to a better understanding of the various enablers of reconfigurability, as well as in the decision-making process, to decide which core characteristic requires more attention, in order to further improve the reconfigurability in existing manufacturing systems
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