A computational fluid dynamics (CFD) study was carried out on a four stroke air cooled DI diesel engine, F912Q manufactured by Beinei Company, by using the KIVA 3V code. A three dimensional mesh was set up to mode...A computational fluid dynamics (CFD) study was carried out on a four stroke air cooled DI diesel engine, F912Q manufactured by Beinei Company, by using the KIVA 3V code. A three dimensional mesh was set up to model the cylinder, intake passage and exhaust passage. The calculated in cylinder pressure history and emissions are compared with the engine test data. The results show reasonable agreement. The effects of swirl ratio and spray angle on fuel spray, evaporation and mixing are investigated. It is found that there are optimum swirl ratio and spray angle for better evaporation and combustion.展开更多
Scattered storage means an item can be stored in multiple inventory bins. The scattered storage assignment problem based on association rules in Kiva mobile fulfillment system is investigated, which aims to decide the...Scattered storage means an item can be stored in multiple inventory bins. The scattered storage assignment problem based on association rules in Kiva mobile fulfillment system is investigated, which aims to decide the pods for each item to put on so as to minimize the number of pods to be moved when picking a batch of orders. This problem is formulated into an integer programming model. A genetic algorithm is developed to solve the large-sized problems. Computational experiments and comparison between the scattered storage strategy and random storage strategy are conducted to evaluate the performance of the model and algorithm.展开更多
本文介绍美国 L os Alamos国家实验室推出的 KIVA程序 ,描述发展的 AL E法。使用 KIVA 程序 ,使日本 YANMAR4TN82柴油机燃烧室为工程计算背景 ,对其中空气运动进行三维数值模拟 ,并对计算结果进行分析 ,从而展示ω型燃烧室内空气动动变...本文介绍美国 L os Alamos国家实验室推出的 KIVA程序 ,描述发展的 AL E法。使用 KIVA 程序 ,使日本 YANMAR4TN82柴油机燃烧室为工程计算背景 ,对其中空气运动进行三维数值模拟 ,并对计算结果进行分析 ,从而展示ω型燃烧室内空气动动变化趋势。展开更多
This article studies the pod layout problem in the Kiva mobile fulfillment system which adopts the synchronized zoning strategy. An integer programming model for the pod layout problem is formulated under the premise ...This article studies the pod layout problem in the Kiva mobile fulfillment system which adopts the synchronized zoning strategy. An integer programming model for the pod layout problem is formulated under the premise of knowing the relationship of the pods and items. A three-stage algorithm is proposed based on the Spectral Clustering algorithm. Firstly, the pod similarity matrix and the Laplacian matrix are constructed according to the relationship of the pods and items. Secondly, the pods are clustered by the Spectral Clustering algorithm and assigned to each zone based on the cluster results. Finally, the exact locations of pods in each zone are determined by the historical retrieval frequency of items, using the real data of a large-scale Kiva mobile fulfillment system to simulate and calculate the order picking efficiency before and after the adjustment of the pod layout. The results showed that the pod layout using synchronized zoning strategy can effectively improve the picking efficiency.展开更多
文摘A computational fluid dynamics (CFD) study was carried out on a four stroke air cooled DI diesel engine, F912Q manufactured by Beinei Company, by using the KIVA 3V code. A three dimensional mesh was set up to model the cylinder, intake passage and exhaust passage. The calculated in cylinder pressure history and emissions are compared with the engine test data. The results show reasonable agreement. The effects of swirl ratio and spray angle on fuel spray, evaporation and mixing are investigated. It is found that there are optimum swirl ratio and spray angle for better evaporation and combustion.
文摘Scattered storage means an item can be stored in multiple inventory bins. The scattered storage assignment problem based on association rules in Kiva mobile fulfillment system is investigated, which aims to decide the pods for each item to put on so as to minimize the number of pods to be moved when picking a batch of orders. This problem is formulated into an integer programming model. A genetic algorithm is developed to solve the large-sized problems. Computational experiments and comparison between the scattered storage strategy and random storage strategy are conducted to evaluate the performance of the model and algorithm.
文摘This article studies the pod layout problem in the Kiva mobile fulfillment system which adopts the synchronized zoning strategy. An integer programming model for the pod layout problem is formulated under the premise of knowing the relationship of the pods and items. A three-stage algorithm is proposed based on the Spectral Clustering algorithm. Firstly, the pod similarity matrix and the Laplacian matrix are constructed according to the relationship of the pods and items. Secondly, the pods are clustered by the Spectral Clustering algorithm and assigned to each zone based on the cluster results. Finally, the exact locations of pods in each zone are determined by the historical retrieval frequency of items, using the real data of a large-scale Kiva mobile fulfillment system to simulate and calculate the order picking efficiency before and after the adjustment of the pod layout. The results showed that the pod layout using synchronized zoning strategy can effectively improve the picking efficiency.
