Hacker News new | past | comments | ask | show | jobs | submit | oxtopus's comments login

Can you elaborate on the "novel anomaly-detection algorithms" used here?


Sure! We evaluated several anomaly-detection tools & libraries. They included:

tried-and-true statistical methods like probability density functions

Yahoo EGADS anomaly-detection library

Numenta HTM neural-network anomaly-detection library

We ruled out HTM due to AGPL licensing concerns. It's an interesting product, but wasn't a good fit for us at this point in time. EGADS and other basic statistical methods can actually get you pretty far.


And what do you do with this video anomaly information?


Mux (https://mux.com/) collects performance metrics for video delivery & playback on the websites & apps of our customers. These metrics feed into our real-time alerting system. If the error-rate for a customer property (site) or video-title is exceptionally high then an alert will be triggered. Mux customers can configure alert notifications to be sent to Slack & email, and view a history of alerts in the Mux web dashboard. We also offer the ability to view breakdowns of playback failures, video start-up times, and more through our dashboard. This can be helpful for diagnosing playback issues related to specific browsers, geographies, ISPs, and more.


Full disclosure: I work at Numenta.

In the HTM model (presumably the Numenta algorithm you're referring to), synaptic weights are updated with every new data point in discrete time steps (as opposed to continuous). In that sense, HTM is an online learning model. There was an experimental implementation of Temporal Memory (one component in HTM) that batched up some of those operations into phases, but that still happened in a single time step and that implementation has since been phased out (pardon the pun).

For some additional literature on the topic, see: - "Why Neurons Have Thousands of Synapses, a Theory of Sequence Memory in Neocortex", http://journal.frontiersin.org/article/10.3389/fncir.2016.00... - "Continuous Online Sequence Learning with an Unsupervised Neural Network Model", http://www.mitpressjournals.org/doi/abs/10.1162/NECO_a_00893... - "The HTM Spatial Pooler: a neocortical algorithm for online sparse distributed coding", http://www.biorxiv.org/content/early/2016/11/02/085035.abstr...


There are more reasons to stay at a company than perceived value of options. Options are only part of overall compensation and, I don't know, maybe you can actually like your job.


See https://github.com/numenta/nab for anomaly detection results on real-world data, with comparisons to Twitter and Etsy Skyline.


Implications are that left mid-superior temporal cortex (LmSTC) carries information about sentence-level meaning, which had kind of already been implied in prior experimentation.

The discussion states that they "Provide preliminary evidence for a long-standing theoretical conjecture of cognitive science: that the brain, on some level, functions like a classical computer, representing structured semantic combinations by explicitly encoding the values of abstract variables", which is little more than hyperbole.

It's interesting, insofar as they identify a very specific region of the brain dedicated to a specific aspect of understanding language, and which plays a small role in a larger network of regions, but it's a bit of a stretch to imply that it's the "most important paper in cognitive neuroscience in many years". Pinker is quoted because this provides some empirical evidence for some of his theories.


I should also add when they mean "architecture" they mean it in the literal sense -- the physical structure in the brain in which encoding sentence meaning takes place.


In Mountain View, and likely elsewhere in the Bay Area, charitable organizations make the rounds once a month to basically do the same. They provide the bags, collect them, and presumably sell what they can for cash. As for batteries and other hazardous materials, there's a protocol to have the city pick them up for no charge. I've never had a problem getting rid of stuff and feeling like I'm doing it responsibly. It's hard to understand what value this adds beyond immediacy.

At least with the services I already take advantage of, it's all done in batches and my contribution is low compared to the overall haul. This is on-demand, so it's likely not as efficient.


Any links you can share to these services? Will have a bunch of stuff to give away soon and I'm not familiar with the various organizations in MV that help with this.



That's awesome, thanks for the link! Are there other non-profits that have similar services or just DAV?


I thought it was weird when I first heard it referred to as espresso, but the official name is "Aerobie® AeroPress® Coffee & Espresso Maker" and there doesn't seem to be any consensus on what _espresso_ actually is. The only common trait is that pressure is used to force water through ground coffee -- the Aeropress does qualify under that definition.


Come on over and visit us at /r/coffee, and we'll set you straight :) There actually is a consensus that "real" espresso has to be brewed with around 9 bar of pressure, and that is the standard used by SCAA ( see http://lrs.ed.uiuc.edu/students/tchen3/espdifine.html ). At this pressure, the consistency and mouth feel of espresso is fundamentally different (it's "syrupy") than that brewed at lower pressure. To achieve this pressure, you need to use an electrical or lever pump. Machines that only get 1-3 bar of pressure like the aeropress or a mocha pot produce something that just tastes more like strong coffee.


Wait, are you saying that the old manual lever-based espresso machines, didn't make espersso? Wikipedia has this to say: "There are two types of lever machines; manual piston and spring piston design. With the manual piston, the operator directly pushes the water through the grounds. In the spring piston design, the operator works to tension a spring, which then delivers the pressure for the espresso (usually 8 to 10 bar; 116 to 145 psi)."

(I'm not disputing the claim that the Aeropress, for all its niceties, doesn't allow for 9 bars of pressure when used as intended)

[ed: That lever contraption is awesome. Searching for appropriate metal filters that could help with generating 130 psi, I fell into the rabbithole of

https://www.tumblr.com/search/aerohacks

and found among other things:

http://www.handpresso.com/

Also, by the makers of the video posted by gp: http://www.spressa.us/ ...]


Actually seems like it'd be a decent use of what became of the ill-fated super collider project south of Dallas. A quarter of it has already been bored.


NuPIC, the Open Source project upon which Grok (Numenta's commercial product) is built has an active community at http://numenta.org/lists/. We had a workshop and hackathon a few weeks ago, more details can be found at http://numenta.com/learn/ and http://numenta.org/blog/2014/10/30/2014-fall-hackathon-outco..., respectively. See, also, https://github.com/numenta/nupic.research for the latest research efforts, https://github.com/numenta/NAB for forthcoming benchmarks, and of course http://numenta.org/ for overall details about NuPIC and http://numenta.com/ for Numenta, the company.


I've been there, having interviewed at both amazon and google and rejected at both. Ultimately, I'm better (and happier) for it. Eventualy found myself in the position of having to choose between multiple better offers. Use this as a learning opportunity -- other opportunities will come along, and this probably isn't the last you'll hear from either google or amazon.


Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: