Flying drones and robots now patrol distribution warehouses - they've become workhorses of the e-commerce era online that retailers can't do without. It is driving down costs but it is also putting people out of work: what price progress?
现在，无人机和机器人开始用于配送仓库巡逻 – 它们已然成为零售商在电商时代不可或缺的主力。这虽然降低了成本，但导致一些人失业：这是富有代价的进步吗？
It could be a scene from Blade Runner 2049; the flying drone hovers in the warehouse aisle, its spinning rotors filling the cavernous space with a buzzing whine.
It edges close to the packages stacked on the shelf and scans them using onboard optical sensors, before whizzing off to its next assignment.
But this is no sci-fi film, it's a warehouse in the US - one of around 250,000 throughout the country, many gargantuan in size: retail giant Walmart's smallest warehouse, for example, is larger than 17 football fields put together.
And these automated drones are now doing the jobs humans - on foot, or operating fork-lift trucks and mechanical lifts - used to do: and they're doing them more cheaply and more accurately.
而现在，这些自动化无人机正在做着人类过去做的工作 - 步行或操作叉车和机械升降机：它们能更准确地完成这些工作并降低人力成本。
"Every year companies lose billions of dollars due to misplaced items and faulty inventory records in their warehouses," says Fadel Adib, an assistant professor of media, arts and sciences at Massachusetts Institute of Technology.
"Today's inventory management requires workers to scan items manually, which is a very time consuming and error-prone process. It's impossible to keep track of all items in the warehouse."
Two drones can do the work of 100 humans over the same time period, according to supply chain specialist, Argon Consulting. This means they can do several tours of a warehouse - even at night - compare results, identify discrepancies, and build up a much more accurate picture much more quickly.
Drone makers claim scanning accuracy of close to 100%.
Matt Yearling, chief executive of Pinc, one of the firms offering such aerial robots, says they can save warehousing and logistics companies millions of dollars.
"Nobody has 100% accuracy - including Walmart and Amazon," he says. "For a warehouse that is 95% accurate, it means that 5% is ambiguous. So if the warehouse is storing $100m [£75m] worth of inventory, then $5m is uncertain.
“没有人能做到100％的准确 - 包括沃尔玛和亚马逊，”他说。 “对于一个准确率为95％的仓库，这意味着有5％是不明确的，因此，如果仓库存有价值1亿美元（7500万英镑）的货物，那么有500万美元是不确定的。
"Typically the retailer will have more than one warehouse. So, if you multiply the problem across the warehouse network you are talking big dollars."
Pinc's drones use hydrogen fuel cells, enabling them to fly for up to two hours - four times as long as some battery-powered drones.
Pinc公司的无人机使用氢燃料电池，能使它们飞行长达两个小时 – 几乎是某些电池供电无人机飞行时长的四倍。