Putting The Brakes On High-Frequency Trading With Physics

February 26, 2019 by Dan Maloney 65 Comments

In the middle of the East Coast’s slow broil in the summer of 2018, a curious phenomenon surfaced. As a tropical air mass settled in and smothered the metropolitan New York area, a certain breed of stock speculator began feeling the financial heat as the microwave signals linking together various data centers and exchanges began to slow down. These high-frequency traders rely on getting information a fraction of a second before other traders see the same thing and take advantage of minuscule price differences to make money hand over fist.

While you won’t catch us shedding many tears over the billions these speculators lost during the hot spell, we did find the fact that humidity can slow microwave propagation enough to make this a problem for them a fascinating subject, enough so that we covered it in some detail at the time. While financial markets come and go and the technology to capitalize them changes at a breakneck pace, physics stays the same, and it can make or break deals with no regard to the so-called fundamentals.

So it was with great interest that we happened upon Tom Scott’s recent video outlining how one new stock exchange is using physics to actually slow down stock trades, in an attempt to gain a competitive advantage over the other exchanges. In light of the billions lost over the summer to propagation delays amounting to a mere 10 microseconds, we couldn’t help but wonder how injecting a delay 35 times longer using a “magic shoebox” was actually good for business. It turns out to be an interesting story.

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New Kinect Sensor Switch Focus From Gamers To Developers

February 26, 2019 by Roger Cheng 31 Comments

Microsoft’s Kinect may not have found success as a gaming peripheral, but recognizing that a depth sensor is too cool to leave for dead, development continued even after Xbox gaming peripherals were discontinued. This week their latest iteration emerged and we can get it in the form of Azure Kinect DK. This is a developer’s kit focused on exploring new applications for this technology, not a gaming peripheral we had to hack before we could use in our own projects.

Packaged into a peripheral that plugs into a PC via USB-C, it is more than the core depth sensor module announced last year but less than a full consumer product. Browsing its 10-page specification (PDF) with comparisons to second generation Kinect sensor bar, we see how this technology has evolved. Physical size and weight has dropped, as has power consumption. Auxiliary capabilities has improved with an expanded microphone array, IMU with gyro in addition to accelerometer, and the RGB camera has been upgraded to 4K resolution.

But the star of the show is a new continuous-wave time-of-flight depth sensor, presented at the 2018 IEEE ISSCC conference. (Full text requires IEEE membership, but a digest form is available via ResearchGate.) Among its many advancements, we expect the biggest impact to be its field of view. Default of 75 x 65 degrees is already better than its predecessors (64 x 45 for first generation Kinect, 70 x 60 for second) but there is an option to trade resolution for coverage by switching to a wide-angle mode of 120 x 120 degrees. Significantly wider than other depth cameras like Intel’s RealSense D400 series or Occipital’s Structure.

Another interesting feature is built-in synchronization. Many projects using multiple Kinect sensors ran into problems because they interfered with each other. People hacked around the problem, of course, but now they don’t have to: commodity 3.5 mm jacks allow multiple Azure Kinect DK to be daisy chained together so they play nicely and take turns.

From its name we were worried this product would require Microsoft’s Azure cloud service in some way and be crippled without it. Based on information released so far, it appears developers have access to all the same data streams as previous sensors. Azure tie-in takes the form of optional SDKs that make it easier to do things like upload data for processing in Azure cloud-based recognition services.

And finally, Azure Kinect DK’s price tag of $399 is significantly higher than a Kinect game peripheral, but it is a low volume product for developers. Perhaps high volume consumer products built on this technology will cost less, but that remains to be seen. In the meantime, you have alternative tools for solving similar problems. For example if you are building your own AR headset, you might use Intel’s latest RealSense camera for vision based inside-out motion tacking.

Reverse Engineering Keeps Keck Telescopes On Track

February 26, 2019 by Dan Maloney 13 Comments

Perched atop a dormant volcano far above the roiling tropical air of the Big Island of Hawai’i sit two of the largest optical telescopes in the world. Each 10-meter main mirror is but a single part of a magnificent machine weighing in at some 400 tons that needs to be positioned with incredible precision. Keeping Keck 1 and Keck 2 in peak operating condition is the job of a team of engineers and scientists, so when the servo amplifiers running the twelve motors that move each scope started to show their age, [Andrew] bit the bullet and rebuilt the obsolete boards from scratch.

The Keck telescopes were built over three decades ago, and many of the parts, including the problematic servo amps, are no longer made. Accumulated wear and tear from constant use and repeated repairs had taken their toll on the boards, from overheated components to lifted solder pads. With only some barely legible schematics of the original amplifiers to go by, [Andrew] reverse engineered new amps. Some substitutions for obsolete components were needed, the PCB design was updated to support SMD parts, and higher-quality components were specified, but the end result is essentially new amplifiers that are plug-in replacements for the original units. This should keep the telescopes on track for decades to come.

Not to sound jealous, but it seems like [Andrew] has a great gig. He’s shared a couple of his Keck adventures before, like the time a failed LED blinded the telescope. He’s also had a few more down-to-earth hacks, like fixing a dodgy LCD monitor and making spooky blinkeneyes for Halloween.