This year researchers expect the world to snap 1.35 trillion photographs, or about 3.7 billion per day. All those pixels (像素) take up a lot of room if they are stored on personal computers or s phones, which is one reason why many people store their images in the cloud. But unlike a hard on drive which can be encrypted to protect its data, cloud storage users have to trust that a tech platform will keep their private pictures safe. Now a team of Columbia University computer scientists has developed a tool to encrypt (加密) images stored on many popular cloud services while allowing authorized users to browse and display their photographs as usual.

Malicious (恶意的) attempts to access or leak cloud-based photographs can expose personal information. In November 2019, for example, a bug in the popular photograph storage app Google Photos mistakenly shared some users' private videos with strangers. Security experts also worry about employees at cloud storage companies on purpose accessing users' images.

So the Columbia researchers came up with a system called Easy Secure Photos (ESP), which they presented at a recent conference. “We wanted to see if we could make it possible to encrypt data while using existing services,” says computer scientist Jason Nieh, one of the developers of ESP. “Everyone wants to stay with Google Photos and not have to register on a new encrypted-image cloud storage service.”

To overcome this problem, they created a tool that preserves blocks of pixels but moves them around to effectively hide the photograph. First, ESP's algorithm (算法) divides a photograph into three separate files, each one containing the image's red, green or blue color data. Then the system hides the pixel blocks around among these three files (allowing a block from the red file, for instance, to hide out in the green or blue ones). But the program does nothing within the pixel blocks, where all the image processing happens. As a result, the files remain unchanged images but end up looking like grainy black-and-white ones to anyone who accesses them without the decryption (解密) key.

Researchers at Ohio State University report that they have been able to recover the sense of a research participant’s hand with a severe spinal cord injury using a brain-computer interface (BCI) system. The technology applies neural signals to the participant, resulting in greatly improved motor function.

The participant in this study is Ian Burkhart, a 28-year-old man who suffered a spinal cord injury during a diving accident in 2010. Since 2014, Burkhart has been working with researchers on a project that aims to recover the function of his right arm. The system they have developed works through a system of electrodes on his skin and a small computer chip inserted into his motor cortex (the brain area that influences motor movements). This setup, which uses wires to route movement signals from the brain to the muscles, bypassing his spinal cord injury, gives Burkhart enough control over his right arm and hand to lift a coffee cup, pick up a credit card, and play Guitar Hero.

The advances in the BCI system led to important improvements. They enable Burkhart to reliably recognize something by touch alone. The system is also the first BCI that allows for recovery of movement and touch at once, and this ability to experience increased touch during movement gives him a greater sense of control and lets him do things more quickly. Finally, these improvements allow the BCI system to sense how much pressure to use when it is handling an object or picking something up.

The researchers are working on creating a next-generation sleeve containing the required electrodes and sensors that could be easily put on and taken off. They also want to improve the system that can be controlled with a tablet rather than a computer, making it smaller and much easier to carry around.

Aeronautics (航空学) specialists from the University of South Australia spent months studying the dragonfly’s (蜻蜓的) night and creating 3D modele from digital images to build a winged drone (无人机). Study leader Javaan Chahl believes that winged drones based on the dragonfly’s shape and movement will simply be more flexible and energy efficient.

Chabl’s team used a special photography technique to classify the wing shapes of 75different dragonfly species from museum collections. Their wings are long, light and hard. Plus, their long bodies give them excellent stability and balance, making it possible for winged drones to deliver awkward loads and undertake long observation missions.

Investigating the way that dragonflies remain stable during flight actually reveals the rechniques they use to get themselves out of tricky situations. Dragonflies are found to be able to perform upside-down back flips to regain balance and normal flight when they find themselves upside down mid-air. This special skill can even be performed while dragonflies are unconscious, which means it is a passive stability mechanism similar in concept to planes that are designed to glide to safety with their engines turned off. Engineers are looking to copy the dragonfly’s wings to create safer drones that can right themselves.

Of course, not all attempts to build dragonfly-like drones are successful. TechJet’s air vehicle was supposed to operate as an aerial camera, observation and security drone, but it failed before production got underway. Similarly, Insectothopter, an American dragonfly spy drone built in the 1970s, was deserted,

Yet the principles behind winged drones are solid. In fact, NASA has settled on a nuclear-powered autonomous craft called Dragonfly to explore the surface of Saturn’s moon Titan in 2034. NASA’s project is actually an air vehicle rather than a winged drone, but engineers are still convinced they can crack the code of nature’s most gifted flying insect and revolutionize unmanned flight along the way.