That’s because there is only one sole cruise ship based in the US.

那是因为美国只有一艘游轮。

The US Navy has ordered all ships based at the Norfolk naval base in Virginia to sea, to ride out the approaching storm.

美国海军已下令所有在诺福克海军基地的船只到海上去，以躲过即将来临的风暴。

They then trained neural networks to recognise ships, based on their characteristic glare of reflected light, and used data such as distance from port, daily speed and nearby signs of marine life to classify their activity.

然后，他们根据反射光特征训练神经网络来识别船只，并使用离港距离、每日速度和附近海洋生物迹象等数据来对船只的活动进行分类。