机械外文文献翻译----起重机调度与空间限制(编辑修改稿)

机械外文文献翻译----起重机调度与空间限制(编辑修改稿)内容摘要：

e different handling and many ports have bulk, container, dry and liquidbulk terminals. Cargo that is containerized can be loaded and unloaded in a fewer number of moves by cranes operating directly over ship holds or by crane arms moving over holds or deck areas. Cargo stacked in yards is moved by cranes onto movers and transported for loading onto ships. “Cargo” here prises containers of different capacities, which, whether in ships or in yards, are parceled into fixed areas for access to cranes. For example, cargo placed in specific holds or deck sections on ships, or in sections within yards. Containers are unloaded from ships by quay cranes onto movers or trailers which carry them to assigned yard locations where they are loaded onto stacks by yard cranes. Containers destined for import are set aside, and restacking, if required, is carried out. In the movement of containers, sequencing is crucial because containers are stored in stacks 3 in the ship and on the yard and lanes may be designated to specific trailers at certain times. In addition, the movement of containers involves routing and crane operations where timings may be uncertain. In fact, crane scheduling is one activity among many that determine the movement of containers. Other such activities include berthing, yard storage, ship stowage and vehicle allocation and routing, all of which can be uncertain. Because of the uncertainty present over all activities, it is almost impossible to implement a plan over any length of time. This difficulty is present in scheduling cranes. For example, although a set of jobs may be assigned to certain crane, it may not be possible for the crane to plete processing a job in this set onto movers once it was known that the route these movers are to take was congested. As another example, although we can specify that jobs bound for the same yard space are not unloaded from ships simultaneously, we cannot expect such containers to be unloaded at a time other than the allotted time interval, since a。