Because air traffic control efficiency can be largely increased by means of group, the aircraft grouping problem was studied based on improved divisive hierarchical clustering algorithm (DHCA). The concepts of position similarity, velocity similarity and heading similarity were defined and the...

The returns to scale (RTS) nature of 37 Chinese airport airsides are investigated in this paper. Multiple optimal solutions in DEA (Data Envelopment Analysis) models may lead to error RTS estimation. To address this problem, we use the (Zhu and Shen, 1995) RTS method. The empirical study shows...

Over the past decades, rainfall amount and frequency changed considerably on the Tibetan Plateau. However, how altered rainfall pattern affects vegetation growth and phenology in Tibetan alpine grasslands is poorly understood. In this study, we investigated the long-term effects of rainfall...