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Comment Re:Article is extremely vague (Score 1) 217

To be fair, these are research projects. The things they describe usually work, but may not have all the properties you would need to make a commercially successful battery. For example, the cell voltage; it should be as high as possible, some cell types are below 1 volt, which is really too low. Or it may not have very good current capacity, so you'd need excessively large membranes. Or loads of other things.

This is primary research, they're announcing that they've managed to get excellent stability, via some mechanism; even if this particular cell doesn't tick all the boxes, the same trick might be applied to other cells to give a really good battery.

And while I haven't read this paper, for a paper to be published it nearly always has to reveal what they did in sufficient detail that it could be reproduced.

User Journal

Journal Journal: A return from facebook 5

Hi world,

I'm currently trying out a new behavior trait: "going back to the way it was before." Sounds exciting, huh. Color me Facebook-less since 1.5 months and frankly, this is the first time since I feel the need to actually share something.

Comment and for pete's sake, MTU!!! (Score 2) 325

A lot of times, bad MTU settings are the problem with a sat link. The problem is simply stated: GRE tunnels are common on such links, and a GRE tunnel will encapsulate each packet and add a 16 byte header. Since the modems usually only permit a 1500 byte MTU, this means the maximum packet size you can get through the GRE tunnel will be 1484 bytes long, inclusive of header. If someone sends out a packet that is maximum size for a 1500 byte MTU, and sets the DF (Don't Fragment) bit, when the packet hits this GRE tunnel it will be dropped. This happens frequently with bad SSL implementations.

This is only one version of MTU problems with sat links. There are others.

Comment Tips for Dan Luu (Score 2) 325

The problem with a satellite connection is not precisely related to latency but rather to jitter, the large differences in latency from one packet to the next. This happens as a result of rain fade, or a poorly engineered link to your transponder on the bird, or a variety of other more infrequent issues.

You can (and should) up your TCP timeout values from the default 3 seconds on a satellite connection, and adjust the http keep-alive timeout, etc, but a lot of times this just means you wait longer to be told when the connection fails.

The solution is a combination of caching, compression, and a performance enhancing proxy or PEP. The PEP does TCP spoofing, basically faking the acknowledgements to speed up the transmission of packets. Compression is similar to the MNP5/v.42bis stuff from modem days applied to a satellite connection. Caching is basically Squid. A lot of PEPs combine all three functions into one - Riverbed is a really good example, though i've worked with pretty much every vendor and they all do the same stuff, with differences in ease of use and efficency.

Implement the timeout fixes, implement a good PEP with all three of the ingredients noted, and make sure the connection is dialed in well with a good shot (line of sight) without physical impediments like trees, buildings, and most importantly microwave interference, and you should have a fairly reliable internet connection. You will still take hits, but you can look at the front of the satellite modem and see that is happening if it's an iDirect or something similar.

Bottom line though is that unless you are taking hits, you should be able to set up downloads of a lot of images and never see a timeout.

- someone who has spent a lot of time doing this (and living off sat connections) in awful places in the world

Comment Re:Wind and Solar are Environmental Disasters (Score 1) 502

They can be a threat for things like eagles that are already threatened and reproduce slowly, but wind turbines otherwise just don't kill enough birdies to matter, compared to, say, cats. Cats kill about a hundred times more birds, because they're good at it, and there's so many more of them than wind turbines.

Comment hyberbole (Score 1) 284

The article linked is just click bait.

The analyst said that Twitter's data quality is "horrible". Chowdhry said that many pollsters used Twitter data to predict a Hillary Clinton win in the U.S. election but the fact that Donald Trump won shows that data quality is poor. One reason for this is too many fake users on the platform, Chowdhry claims.

Twitter has had issues with monetization, but the idea that the platform is somehow flawed because some idiot used it as a source polling is nuts. You can't determine an election from reading tweets.

Twitter differentiated itself from other social sites by embracing simplicity and mobile. The simplicity of twitter has also hurt it, because it keeps failing at expanding the platform beyond tweets making it a poor growth stock since its user growth has stagnated.

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