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W e propose a new hierarchical scheme for yard crane (YC) workload management in container terminals.We also propose a time partitioning algorithm and a space partitioning algorithm for deploying YCs to handle changing job arrival patterns in a row of yard blocks. The main differences between our approach and most of the methods in literature are (1) the average vehicle job waiting time instead of the number of jobs is used to balance YC workload and to evaluate the quality of a partition, (2) the YC working zone assignment is not in units of yard blocks and our space partitioning algorithm generates more flexible divisions of the workload from all blocks, and (3) the YC deployment frequency is not fixed but is decided by our time partitioning algorithm with the objective of minimizing average vehicle waiting times. The scheme combines simulation and optimization to achieve our objective for a row of yard blocks. Experimental results show that the proposed binary partitioning algorithm TP2 makes substantial improvements in job waiting times over the basic partitioning scheme and another existing algorithm (Ng, W. C. 2005. Crane scheduling in container yards with intercrane interference. Eur. J. Oper. Res. 164(1) 64-78) in all tested job arrival scenarios.

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The mechanisms of heat generation and heat dissipation of tire are first discussed, and the heat generation capacity and the heat dissipation capacity per unit time are obtained through the analysis of both tire contact pressure distribution and heat dissipation method. Then, according to heat balance condition of tire, the theory model of the steady-state surface temperature of tire is established based on tire temperature field tests. Finally, the effects of speed, load, and tire pressure on the steady-state surface temperature of tire are analysed. The results show that the established model of the steady-state surface temperature of rolling tire is feasible, and the results can reflect the thermal conditions of tire, and therefore provides a theoretical foundation to predict the steady-state surface temperature for various types of tires under different driving conditions.