Abstract: In migrating workflow system，migrating instance is the executive agents of the workflow，which can migrate continuously among places prescribed by the itinerary graph，use the services those places provide and finish one or more tasks.This paper provides an itinerary graph generation algorithm based on task segments.Task segment means a task sequence which can be executed sequentially on the same place.Organizing itinerary graphs according to task segments，can not only help to ensure executive semantic of business processes，but also reduce the risk from migration failure and migration security by cutting down the number of migration.

Key words: migrating workflow, migrating instance, itinerary graph, task segment

摘要： 在迁移工作流模型中，迁移实例是工作流的执行主体，它可以在旅行图规定的工作位置之间连续迁移并利用位置服务完成一项或多项任务。给出一种基于任务片的旅行图生成算法，任务片是指可以在同一个工作位置上连续执行的任务序列。按照任务片组织旅行图，不仅有利于保证业务过程的执行语义，而且可以通过减少迁移次数，降低移动故障和移动安全导致的风险。

关键词: 迁移工作流, 迁移实例, 旅行图, 任务片