Pool Watch

    Swimmers can drown in busy swimming pools when lifeguards fail to notice that they are introuble. The Royal Society for the Prevention of Accidents says that on average 15 people drown in British pools each year, but many more suffer major injury after getting into difficulties. Now a French company has developed an artificial intelligence system called Poseidon that sounds thealarm when it sees someone in danger of drowning.

    When a swimmer sinks towards the bottom of the pool, the new system sends an alarm signal to a poolside monitoring station and a lifeguard"s pager. In trials at a pool in Ancenis, it saved a life with in just a few months, says Alistair McQuade,a spokesman for its maker, Poseidon Technologies.

    Poseidon keeps watch through a network of underwater and overhead video cameras. AI software analyses the images to work out swimmers" trajectories. To do this reliably, it has to tell the difference between a swimmer and the shadow of someone being cast onto the bottom or side of the pool. "The underwater environment is a very dynamic one, with many shadows and reflections dancing around", says McQuade.

    The software does this by "projecting" a shape in its field of view onto an image of the far wall of the pool. It does the same with an image from another camera viewing the shape from a different angle. If the two projections are in the same position, the shape is identified as a shadow and is ignored. But if they are different, the shape is a swimmer and so the system follows its trajectory.

    To pick out potential drowning victims, anyone in the water who starts to descend slowly is added to the software"s "pre-alert" ¹list,says McQuade. Swimmers who then stay immobile on the pool bottom for 5 seconds or more are considered in danger of drowning. Poseidon double-checks that the image really is of a swimmer, not a shadow, by seeing whether it obscures the pool"s floor texture when viewed from overhead. If so, it alerts the lifeguard, showing the swimmer"s location ona poolside screen.

    The first full-scale Poseidon system will be officially opened next week at a pool in High Wycombe, Buckinghamshire. One man who is impressed with the idea is Travor Baylis, inventor of the clockwork radio. Baylis runs a company that installs swimming pools - and he was once an underwater escapologist with a circus. “I say full marks to them if this works and can save lives", he says. But he adds that any local authority spending ~30,000 - plus on a Poseidon system ought to be investing similar amounts in teaching children to swim.

词汇：

pager [ˈpeɪdʒə(r)] 携带式电子呼叫机

trajectory [trə"dʒektərɪ]轨迹

descend [dɪ"send]下降

immobile [ɪ"məʊbaɪl] 不移动的

texture ["tekstʃə(r)]特征，质地

clockwork [ˈklɔkˌwɜ:k] 时钟机构

escapologist [ˌeskəˈpɒlədʒɪst] 擅长从捆扎的绳索中脱身的杂技演员

注释：

1 pre-alert：预先警戒的。the software"s“pre -alert”list：软件的“预警”名单。pre-：是前缀，意思是先于；预先。又如：preadult：成年前的；precancerous：癌症前期的。alert：警戒的，警觉的。

AI means the same as _

A:an image B:an idea C:anyone in the water D:artificial intelligence

Pool Watch

    Swimmers can drown in busy swimming pools when lifeguards fail to notice that they are introuble. The Royal Society for the Prevention of Accidents says that on average 15 people drown in British pools each year, but many more suffer major injury after getting into difficulties. Now a French company has developed an artificial intelligence system called Poseidon that sounds thealarm when it sees someone in danger of drowning.

    When a swimmer sinks towards the bottom of the pool, the new system sends an alarm signal to a poolside monitoring station and a lifeguard"s pager. In trials at a pool in Ancenis, it saved a life with in just a few months, says Alistair McQuade,a spokesman for its maker, Poseidon Technologies.

    Poseidon keeps watch through a network of underwater and overhead video cameras. AI software analyses the images to work out swimmers" trajectories. To do this reliably, it has to tell the difference between a swimmer and the shadow of someone being cast onto the bottom or side of the pool. "The underwater environment is a very dynamic one, with many shadows and reflections dancing around", says McQuade.

    The software does this by "projecting" a shape in its field of view onto an image of the far wall of the pool. It does the same with an image from another camera viewing the shape from a different angle. If the two projections are in the same position, the shape is identified as a shadow and is ignored. But if they are different, the shape is a swimmer and so the system follows its trajectory.

    To pick out potential drowning victims, anyone in the water who starts to descend slowly is added to the software"s "pre-alert" ¹list,says McQuade. Swimmers who then stay immobile on the pool bottom for 5 seconds or more are considered in danger of drowning. Poseidon double-checks that the image really is of a swimmer, not a shadow, by seeing whether it obscures the pool"s floor texture when viewed from overhead. If so, it alerts the lifeguard, showing the swimmer"s location ona poolside screen.

    The first full-scale Poseidon system will be officially opened next week at a pool in High Wycombe, Buckinghamshire. One man who is impressed with the idea is Travor Baylis, inventor of the clockwork radio. Baylis runs a company that installs swimming pools - and he was once an underwater escapologist with a circus. “I say full marks to them if this works and can save lives", he says. But he adds that any local authority spending ~30,000 - plus on a Poseidon system ought to be investing similar amounts in teaching children to swim.

词汇：

pager [ˈpeɪdʒə(r)] 携带式电子呼叫机

trajectory [trə"dʒektərɪ]轨迹

descend [dɪ"send]下降

immobile [ɪ"məʊbaɪl] 不移动的

texture ["tekstʃə(r)]特征，质地

clockwork [ˈklɔkˌwɜ:k] 时钟机构

escapologist [ˌeskəˈpɒlədʒɪst] 擅长从捆扎的绳索中脱身的杂技演员

注释：

1 pre-alert：预先警戒的。the software"s“pre -alert”list：软件的“预警”名单。pre-：是前缀，意思是先于；预先。又如：preadult：成年前的；precancerous：癌症前期的。alert：警戒的，警觉的。

What is required of AI software to save a life?

A:It must be able to swim B:It must keep walking round the pool C:It can distinguish between a swimmer and a shadow D:It can save a life within a few months

对适宜摄人量（AI）的解释，错误的是（）。

A:相当于过去的RDA B:与RNI相似，二者都能满足目标人群中几乎所有个体的需要 C:如长期摄入超过AI，则有可能产生不良反应 D:是通过观察或实验获得的健康人群某种营养素的摄入量 E:与RNI的区别在于AI的准确性不及RNI，其数值可能高于RNI

关于AI和RNI，下列说法正确的是（）。

A:AI和RNI都是个体摄入量的目标值 B:AI的准确性不如RNI C:AI和RNI计算方法不同，表示的意义相同 D:AI通常比RNI高 E:AI通常比RNI低

AI

关于AI和RNI，下列说法正确的是( )。

A:AI和RNI都是个体摄入量的目标值 B:AI的准确性不如RNI C:AI和RNI计算方法不同，表示的意义相同 D:AI通常比RNI高 E:AI通常比RNI低

关于AI和RNI，下列说法正确的是( )。

A:AI和RNI都是个体摄入量的目标值 B:AI的准确性不如RNI C:AI和RNI计算方法不同，表示的意义相同 D:AI通常比RNI高 E:AI通常比RNI低