Besides showing the flow between the actions in an activity like a flowchart, the activity diagram can also show parallel or concurrent flows and alternate flows.
除了展示活动中动作之间的流，类似流程图，活动图还可以展示并行或并发的流，及交替的流。
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Workplace security: Once again , we can use the concept of feedforward, concurrent . and feedback control to identify actions that managers can take.