Identifying rail asset maintenance processes: a human-centric and sensemaking approach

Efficient asset maintenance is key for delivering services such as transport. Current rail maintenance processes have been mostly reactive with a recent shift towards exploring proactive modes. The introduction of new ubiquitous technologies and advanced data analytics facilitates the embedding of a ‘predict-and-prevent’ approach to managing assets. Successful, user-centred integration of such technology is still, however, a sparsely understood area. This study reports results from a set of interviews, based on Critical Decision Method, with rail asset maintenance and management experts regarding current procedural aspects of asset management and maintenance. We analyse and present the results from a human-centric sensemaking timeline perspective. We found that within a complex sociotechnical environment such as rail transport, asset maintenance processes apply not just at local levels, but also to broader, strategic levels that involve different stakeholders and necessitate different levels of expertise. This is a particularly interesting aspect within maintenance that has not been discussed as of yet within a process-based and timeline-based models of asset maintenance. We argue that it is important to consider asset maintenance activities within both micro (local) and macro (broader) levels to ensure reliability and stability in transport services. We also propose that the traditionally distinct notions of individual, collaborative and artefact-based sensemaking are in fact all in evidence in this sensemaking context, and argue that a more holistic view of sensemaking is therefore appropriate by placing these results within an amended Recogntion Primed Decsion making model

An iterative algorithm for the Max-Min knapsack problem with multiple scenarios

In this paper, we propose to solve the max-min knapsack problem with multiple scenarios by using an iterative algorithm that uses three main phases: (1) construction phase, (2) improvement phase, and (3) destroying/repairing phase. The first phase yields a (starting) pool of elite solutions for the problem by applying a greedy randomized search. The second phase tries to improve each solution at hand by using an intensification search using path-relinking combined with a look-ahead strategy. The third phase can be viewed as a diversification strategy, where the iterative algorithm tries to avoid premature convergence towards local optima. Finally, the proposed method is evaluated on a set of benchmark instances taken from the literature. Its obtained results are compared to those reached by recent algorithms available in the literature. The computational part shows that the method remains competitive (in term of the quality of solutions achieved), where it is able to provide better bounds than those already published ones. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature

Structural, optical and electrical properties of Cu2Zn1−xCdxSnS4 quinternary alloys nanostructures deposited on porous silicon

Tyto nanostruktury quinternarních slitin Cu2Zn1-xCdxSnS4 s různým obsahem Cd byly pěstovány pomocí odstřeďovací techniky potahováním porézního substrátu křemíku (63,93%). Strukturní vlastnosti Cu2Zn1-xCdxSnS4 / PS byly zkoumány pomocí rentgenové difrakce a pole pomocí emisního elektronového mikroskopu (FE-SEM).The Cu2Zn1−xCdxSnS4 quinternary alloy nanostructures with different Cd contents were grown using spin coating technique on porous silicon (63.93 %) substrate. The structural properties of Cu2Zn1−xCdxSnS4/PS were investigated by X-ray diffraction and field emission-scanning electron microscope (FE-SEM)

External temperature and pressure effects on thermodynamic properties and mechanical stability of yttrium chalcogenides YX (X=S, Se and Te)

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