Facility disruptions in the supply chain often lead to catastrophic consequences, although they occur rarely. The low frequency and non-repeatability of disruptive events also make it impossible to estimate the disruption probability accurately. Therefore, we construct an uncertain programming model to design the three-echelon supply chain network with the disruption risk, in which disruptions are considered as uncertain events. Under the constraint of satisfying customer demands, the model optimises the selection of retailers with uncertain disruptions and the assignment of customers and retailers, in order to minimise the expected total cost of network design. In addition, we simplify the proposed model by analysing its properties and further linearise the simplified model. A Lagrangian relaxation algorithm for the linearised model and a genetic algorithm for the simplified model are developed to solve medium-scale problems and large-scale problems, respectively. Finally, we illustrate the effectiveness of proposed models and algorithms through several numerical examples. 相似文献
3D Concrete Printing (3DCP) is a rapidly expanding area in the field of architecture, engineering, and construction, but very limited research has quantitatively investigated its environmental impact. The existing Life Cycle Assessment (LCA) studies on 3DCP lack clearly defined functional units of comparison, especially considering load-bearing structures. This paper investigates the potential environmental benefits of 3DCP over conventional concrete construction for structural beams based on a cradle-to-grave comparative LCA. Unlike existing studies, this paper employs a recarbonation model to account for the carbon offsetting from the use-stage of 3DP concrete, which shows significant results. The assessment includes three-beam designs, each analyzed for both prefabrication and on-site construction scenarios. While currently, 3DCP has a generally higher environmental impact due to the larger quantity of cement employed in the process, the reduction of material through infill optimization for printed beams is a promising design principle to positively offset the environmental impacts in the construction sector. The paper draws recommendations for future research on material- and recarbonation-efficient 3DCP design for load-bearing structures, as well as on material development, e.g. integration of larger aggregates and low-clinker cement.
International Journal on Software Tools for Technology Transfer - FairFuzz is a coverage-guided mutational fuzzing tool based on AFL, which targets its mutation strategy towards rare branches in... 相似文献
Stochastic structural analysis can assess whether a fabricated object will break under real-world conditions. While this approach is powerful, it is also quite slow, which has previously limited its use to coarse resolutions (e.g., 26 × 34 × 28). We show that this approach can be made asymptotically faster, which in practice reduces computation time by two orders of magnitude, and allows the use of previously-infeasible resolutions. We achieve this by showing that the probability gradient can be computed in linear time instead of quadratic, and by using a robust new scheme that stabilizes the inertia gradients used by the optimization. Additionally, we propose a constrained restart method that deals with local minima, and a sheathing approach that further reduces the weight of the shape. Together, these components enable the discovery of previously-inaccessible designs. 相似文献
A novel image-based defect identification and coding technique has been proposed for fluted ingots, which are used for the production of locomotive wheels. The edge density map has been used for defect identification and an object-based coding approach has been applied for the storage of defective ingots. The complete scheme has been implemented in one of the integrated steel plants of India. 相似文献