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Recent arXiv Reads

posted on October 13 2017

This is as much for me as for anyone else, just to track what I've read and what I haven't:

As you can probably guess, this year I've spent a lot of time thinking about galactic composition and trying to get my head around a few key questions:

So if dark matter is a requirement to understand what we see in observed galaxies, how are we identifying velocities of individual stars in distant objects?
What's the most distant galaxy we can see where individual stars are identifiable and whose velocity can be accurately measured?
Considering the fact that when we look at a galaxy we're looking at an object where there is a significant delay from the far side of the object to the near side of the object (imagine a coin on a table arms length from you) on the order of hundreds of thousands of years, does this change what we expect to observe when it comes to spectral analysis?
Assuming dark matter was present, what affect would this have on the evolution of the early universe?
We talk about different epochs in the evolution of the universe w/r/t quark gluon plasma, the hadron epoch, recombination, etc. Are there similar epochs that would have focused on dark matter?
Since dark matter appears to be non-interacting and non-collisional, what does compression of dark matter result in?
Does identification of dark matter result in a shortcut to quantum gravity? Since there appears to be no such thing as a macroscopic clump of dark matter, the main way that we would describe the behavior of dark matter would be at the quantum level.
What is the presumed quantum model of dark matter? Since it appears to be non-interacting, is there anything we can even say about quantum dark matter?
How are dark matter models presumed to work with black holes? Can dark matter be assumed to have finite density?

Ok, so more than a few questions.

Everyone hates passwords. It's hard for people to come up with passwords that they can remember and which match the inconsistent standards set by websites. The result is that they figure out one password that generally fits the standards and then use that everywhere they can. Password expiration policies that prevent users from reusing passwords actually make the problem worse, since they encourage users to use simpler passwords than they would otherwise.

The function of any password is to prove identity and therefore determine authorization. A password is paired with a username to provide two pieces of information that only an authorized user of a system would know. The fact that usernames have shifted to being the same as the user's email actually makes the problem worse. It means that there are options to determine usernames rather than just guessing them, since people tend to have a very small number of email addresses they use. Most people have one personal address that they use for many years and a work address, and rarely more than that.

It's unlikely that email addresses will stop being used for authentication since they're guaranteed to be unique and users like them. That puts even more focus on making sure passwords are effective. The minimal characteristics that any password must have are:

It can't be easy to guess.
It needs to be able to be remembered.
It must be unique for each website.

So what about password managers? They meet the first and last requirements and they remove the second requirement, but they introduce other problems. Synchronization between devices is non-trivial and requires the password manager to be present in each computing environment. It also requires integrations to allow passwords to be copy and pasted from the password manager into each application that it's being used with. It also provides a single point of failure. If someone has access to your password manager, or the password to your password manager, has access to all of your accounts.

Using the XKCD method, we've come up with a process of password construction that manages to satisfy the first two requirements. To supplement Randall's approach we should also add something unique for each website. The easiest way is to add something about the website (or application) itself.

Let's start with a unique core that we can remember: coppertrucks

Now let's add a number, an uppercase letter, and a special character to satisfy most password requirements: C0ppertruck$

Finally, let's say we're logging into facebook.com. We can have a universal rule that says we take the first letter and last letter from the URL and add them to the beginning of the password route: fkC0ppertruck$

For nytimes.com we can apply the same rule and come up with an entirely unique password: nsC0ppertruck$

Fish - My Favorite New Shell

posted on May 31 2017

I settled into bash back in college, and I rarely think about it. It quickly became my default option once I spent most of my time in a Unix environment, and was one of the primary reasons why I switched from using Windows to OS X long long ago.

I'm not really what you'd call a power user of bash. I have a bunch of aliases that I like to set up on a new machine. I know a lot of the standard commands and configs. It's not like I typically write a lot of bash scripts, though, and when I need to I'm always looking up tutorials and references to do what I need to do.

So I was listening to The Talk Show and they were talking about some of the features in Fish. The more useful approach to auto-complete was enough to get me to at least try it, and so I have. Installation was a breeze thanks to homebrew, and I was up and running in a few minutes.

I'm still making up my mind on whether or not this is a permanent switch, but I'm pretty sure this is my new shell. The one downside is that it now makes my working environments inconsistent. I'm on MacOS at work and at home, but I spend a fair amount of time SSHed into machines that I can't just install new shells on. I always favor consistency over features, but I might make an exception in this case.

If you spend most of your time in a shell then you should check out Fish. You might just love it too. As an extra bonus, check out this video.

Giant Isopod - Plush

posted on February 13 2014

There's a lot of things to admire and fear about the oceans, but the prescence of giant isopods is right up there at the top. You no longer need to endanger your health and the health of your pets to have one in your life, though. Amazon has you covered. I'm guessing they're going to be hot for Xmas, so get one now!

Hubble Ultra Deep Field 3-D Fly-Through

posted on August 30 2013

This is a pretty incredible simulation and it's the best thing I've seen all day.

A flight through the Hubble Ultra Deep Field, the most distant visible-light view of the universe. The redshifts of 5,333 galaxies were converted to distances to assemble a 3-D model of the data. This scientific visualization flies through the data to showcase its true 3-D nature.

Catching Creative Ideas

posted on August 29 2013

The Atlantic has put together this great video by Annie Lennox on creativity and how she maintains a creative approach to her work. It's so great hearing more about how people see their work and how they manage to make it look effortless even when it's difficult.

What is Algebra?

posted on August 28 2013

I'm biased, but I love discussions of the nature of mathematics, especially when they're targeted at mathematical novices. Algebra was one of the areas of math that I spent quite a lot of time on in college, and it holds my interest like no other. Keith Devlin has a very interesting analysis of what algebra actually is:

The important thing to realize is that doing algebra is a way of thinking and that it is a way of thinking that is different from arithmetical thinking. Those formulas and equations, involving all those x’s and y’s, are merely a way to represent that thinking on paper. They no more are algebra than a page of musical notation is music. It is possible to do algebra without symbols, just as you can play and instrument without being ably to read music.

It's this kind of insight that is typically not present in most mathematical courses, and I feel it's a huge part of why so many people have significant math anxiety. They don't really know what they're doing, and more importantly, they don't know why they're doing it. Removing the big picture means that the entire context of math is gone, and so each new chapter in the mathematics text book becomes disconnected from every other.

Cray Resurrection

posted on August 25 2013

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There was a time in middle school where I, and many of the other deep nerds would sit around and fantasize about the monumental computational feats that could be accomplished through personal ownership of a Cray supercomputer. We didn't really know what we were talking about, but we did know that this was supposed to be the fastest computer that ever existed, and therefore it was an object of reverence and awe. Well, Chris Fenton is living the dream of my middle school years. Not only did he create his own 1/10-scale, binary-compatible, cycle-accurate Cray-1, but he then reconstituted the operating system for it from an old 80MB disk pack.

One of the largest problems encountered with the cleaning process was that the entire case of the drive was lined with 1/4” thick noise canceling foam that had degraded over time. Any contact with the foam would cause it to crumble into dust, something potentially disastrous if it were to contaminate the disk cavity, and ultimately all of it needed to be carefully removed. Additional problems were encountered from the large number of spiders that had taken up residence inside the disk drive, as well as a 3”-diameter (thankfully abandoned) “mud dauber” wasp nest that had been constructed within the drive.

It's worth a read, and the whole story is surprisingly gripping. The other great thing about the article, though, is the number of old illustrations that document an approach to computing that is now absent. Where it was assumed that every component needed to be documented in the case that a new piece would have to be recreated rather than simply discarded and repurchased.

Shakespearean Authorship

posted on August 25 2013

There are a hard-core group of conspiracy theorists who continue to insist that William Shakespeare was somehow not the actual author of the plays and poems that are attributed to him. In an attempt to stop the madness, Tom Reedy and David Kathman have created the most extensive list of evidence I've seen. Here's the conclusion, but reading the actual list of evidence is fascinating:

How do we know that Shakespeare wrote Shakespeare? We know because the historical record tells us so, strongly and unequivocally. The historical evidence demonstrates that one and the same man, William Shakespeare of Stratford-upon-Avon, was William Shakespeare the player, William Shakespeare the Globe-sharer, and William Shakespeare the author of the plays and poems that bear his name -- and no person of the Elizabethan and Jacobean eras ever doubted the attribution. No Elizabethan ever suggested that Shakespeare's plays and poems were written by someone else, or that Shakespeare the player was not Shakespeare the author, or that Shakespeare the Globe-sharer was not Shakespeare of Stratford. No contemporary of Shakespeare's ever suggested that the name used by the player, the Globe-sharer, or the author was a pseudonym; and none of the major alternative candidates -- not Francis Bacon, not the Earl of Oxford, not Christopher Marlowe -- had any connection with Shakespeare's acting company or with his friends and fellow actors.

Soda - yet another reason to avoid it

posted on August 24 2013

This is a week old, but if you didn't already avoid feeding your kids soda, here's another reason to consider it.

In order to evaluate the relationship between the sugared drinks and behavior problems, the researchers adjusted for several factors that can influence behavior, including their mothers’ depression and the children’s diets. Even after this adjustment, the scientists found a significant relationship between more soda consumption and aggressive behaviors that included destroying other people’s belongings, getting into fights and physically attacking others.

The most horrifying thing in this article was the fact that four servings of soda per day is considered "normal."

Encryption: less secure than previously thought

posted on August 23 2013

Coming on the heels of the various revelations about the NSA's activities, this article in MIT News is fascinating reading:

When Médard, Duffy and their students used these alternate measures of entropy, they found that slight deviations from perfect uniformity in source files, which seemed trivial in the light of Shannon entropy, suddenly loomed much larger. The upshot is that a computer turned loose to simply guess correlations between the encrypted and unencrypted versions of a file would make headway much faster than previously expected.

The point here is that encryption is still secure. It's just not *as* secure as we might have assumed.

Neeman Tools

posted on August 22 2013

I could watch videos like this all day. Nothing compares to a craftsman putting things together in a traditional way.

The Camera Bubble Has Burst

posted on August 21 2013

I knew camera sales were down, especially in the non-SLR segment, but I had no idea they were down so much.

But cellphones have been gently eroding the market for the past four years. Why the swift and sudden plunge of conventional cameras over the cliff? My take? The vast majority of buyers of all cameras, DSLR's, mirror less, high end compacts, etc. were hobbyists and amateur photographers who, after years of pursuing some sort of competence in the craft have come to the conclusion that the whole art genre of photography is somewhat of a dead end.

I think this is a really interesting take on the current state of the camera market. Once everyone has an incredible camera in their pocket that happens to come with their phone, and once all cameras on the market effectively do the same thing, what is driving camera sales? I think the answer is pretty clear; nothing is driving sales. We're currently dealing with an over-saturation of content and technology and the result is flat-lined growth.

Project Euler

posted on August 21 2013

Are you into math? Want to show off your skills? Then Project Euler is for you:

Project Euler is a series of challenging mathematical/computer programming problems that will require more than just mathematical insights to solve. Although mathematics will help you arrive at elegant and efficient methods, the use of a computer and programming skills will be required to solve most problems.The motivation for starting Project Euler, and its continuation, is to provide a platform for the inquiring mind to delve into unfamiliar areas and learn new concepts in a fun and recreational context.

Adding iodine to table salt also added IQ points?

posted on August 16 2013

From Discover magazine comes this fascinating article on iodized salt in the US and how it may have added IQ points to the population:

Iodine deficiency today is the leading cause of preventable mental retardation in the world. It’s estimated that nearly one-third of the world’s population has a diet with too little iodine in it, and the problem isn’t limited to developing countries—perhaps one-fifth of those cases are in Europe (pdf), where iodized salt is still not the norm...

The economists found that in the lowest-iodine areas—the bottom quarter of the study population—the introduction of iodized salt had stark effects. Men from these regions born in 1924 or later were significantly more likely to get into the Air Force and had an average IQ that was 15 points higher than their predecessors.

It's always dangerous to draw conclusions about causative relationships, but this is one of the most fascinating articles I've read in some time. It's enough to make me want to switch back from kosher salt.

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