If someone created a flying machine capable of tracking you down by listening for your voice, you might be terrified. But what if you were trapped in ruins after a natural disaster and first responders couldn't locate you? Maybe then a human-seeking drone(无人机)wouldn't be such a terrible idea. That concept is the focus for engineers at Germanys Fraunhofer FKIE Institute, who've built a drone to find people by detecting(探测)human screams.

"The human-seeking drone would be ideal for post-disaster situations, such as earthquakes, hurricanes and wildfires," said Macarena Varela, one of the lead engineers "They could hover over an area that rescue crews have difficulty getting to and locate exactly where people may be trapped."

Locating people by sound presents its share of challenges. An auditory(听觉的) system would need to distinguish human cries from sounds that often happen in nature such as animal calls and wind. It might also need to recognize patterns associated with kicking, clapping or other ways people try to get the attention of rescue teams.

Engineers took those situations into account when building out their concept drone. They recorded themselves screaming, tapping and creating other noises that might be a sign of people in trouble. Then, they analyzed each sound frequency to find common signatures and used those to train artificial intelligence software. They also worked to remove the noise created by the drone and other environmental sounds.

Once the software part was complete, the team placed tiny digital microphones under the drone and used signal processing techniques that enabled them to track where human noises are coming from. The microphones also enhanced the volume and clarity of the speech. So far, they have conducted successful open field experiments, finding that the drone can estimate a victim's location within a few seconds of picking up sound.

Next, they would like to add a higher frequency microphone to a drone to acquire more audio sound signals. The idea is to pick up noises from hundreds of meters away. Varela said. In the real world, victim's location data might one day be sent wirelessly to emergency crews carrying a tablet.

One of the world's greenest office buildings will formally open its doors this week. It's a project of the environmentally progressive Bullitt Foundation. Its ambition is bold: to showcase an entirely self-sustaining office building hoping that others will create similar projects.

The first thing that strikes you about the new Bullitt Center is an emphasis on walking. "In a building this size, any place else in Seattle it would have two elevators. Here, the stairway is obvious and attractive,"says Denis Hayes, CEO of the foundation. He explains there is an elevator, but it's well-hidden. The staircase encourages exercise and the concept helps cut down on energy use.

This is one of dozens of visionary decisions that went into this building. "It has eyes, ears, a nervous system and a brain and it responds to its environment in a way that seeks to optimize （优化） things," he says. He points across the street to a mini weather station. It sends data to the building so it can decide what it should do to conserve energy.

"I think it's fair to say we were all a bit skeptical in the beginning, "says Chris Rogers, the founder of a firm in cooperation with the foundation. Rogers and the others set out to meet the ambitious goals of the Living Building Challenge, a green building standard set by local architects.

Clearly this building is not for everyone. If you think of it as simply an office building, it was relatively pricey to design and build. But if you view it as a laboratory, an educational center and a bold effort to change how things are built, the calculation changes.

Still, one could wonder, is it possible to build more with similar self-sustaining features at a reasonable cost? "If this building isn't reproducible, then this experiment will have failed, says Rogers. But if it is successful, he's optimistic others will follow the foundation's lead. Rogers points out that over the past couple of decades, many builders have been integrating green elements into their buildings.

Devon—A three-year-old labradoodle named Digby has been praised after he saved a woman who was thinking of taking her own life on a bridge.

Digby is an Australian labradoodle, a type of dog, whose hypoallergenic (低致敏性的) coat is less likely to start allergic reactions in those he communicates with. He was hired by the fire service in 2018 not for his ability to remove bombs but to relieve stress and anxiety among firefighters who had attended unpleasant call-outs. He also works with vulnerable (脆弱的) people in the community as part of a "pets for therapy" programme.

So when the emergency services were called to a vulnerable woman on a motorway bridge, a firefighter had the bright idea to take Digby along.

"We were at the incident as part of a multi-agency response. Police negotiators were speaking with the woman but the situation was becoming increasingly worrying. When Digby arrived, the young woman immediately swung her head round to look, and smiled," said a spokesman for Devon and Somerset fire service. "This got a conversation started. The woman was asked if she would like to come and meet Digby if she came back over the railings (金属栏杆), which we are pleased to say she did. It was Digby who eventually got her out of harm's way."

"The use of therapy dogs has been scientifically proven to help people who are exposed to challenging situations in their lives such as ill health or learning disability," the spokesman added.

Digby has also been trained to go into schools and hospitals for Pets As Therapy charity. Other services have also started adopting therapy dogs to assist in various situations.