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Winner: Poseidon Discovery

The world’s leading designer of scuba gear brings closed-circuit rebreathers to the masses

4 min read
man in water wearing Poseidon Diving Systems CCR
Photo: Poseidon Diving Systems

This month, Swedish scuba manufacturer Poseidon Diving Systems plans to introduce an electronically controlled closed-circuit rebreather (CCR) called Discovery, which promises to change mainstream sport diving the way Microsoft Windows changed computing. Rebreathers, which have been around for decades, greatly increase dive time but at an enormous cost in complexity, training, and setup time. Poseidon’s new system is designed to do away with all that. In October, the company gave me the system for a 30-minute test splash during a trade show in Las Vegas.

To see what sets Discovery apart, let’s review some scuba basics. The conventional scuba equipment that Jacques Cousteau introduced in 1943 has an open circuit. The regulator supplies air from the tank, and your exhaled breath vents into the water as bubbles. Your body uses only a fraction of the oxygen in each breath; the rest is wasted. At higher pressures, each breath takes more from your cylinder, so you use up your air faster just when you need it the most—on your deepest dives.

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From WinZips to Cat GIFs, Jacob Ziv’s Algorithms Have Powered Decades of Compression

The lossless-compression pioneer received the 2021 IEEE Medal of Honor

11 min read
Photo of Jacob Ziv
Photo: Rami Shlush

Lossless data compression seems a bit like a magic trick. Its cousin, lossy compression, is easier to comprehend. Lossy algorithms are used to get music into the popular MP3 format and turn a digital image into a standard JPEG file. They do this by selectively removing bits, taking what scientists know about the way we see and hear to determine which bits we'd least miss. But no one can make the case that the resulting file is a perfect replica of the original.

Not so with lossless data compression. Bits do disappear, making the data file dramatically smaller and thus easier to store and transmit. The important difference is that the bits reappear on command. It's as if the bits are rabbits in a magician's act, disappearing and then reappearing from inside a hat at the wave of a wand.

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