Saturday, September 29, 2012

Wedding in Louisiana

Last weekend, Kristin and I went down to Louisiana, where my sister, Rebekah, was getting married.  It was a simple, and relatively inexpensive, wedding at my parents' home in St. Francisville.  Here's a picture, so you can get an idea of what it looked like.

The wedding party.  My sister and Vance with the minister in the center.  My other sister, Sarah, on the right, and her daughter, Hope, in the white dress in front of the groom's party (she was a co-ring-bearer, since there were already three flower girls).

The minister and the bride and groom are standing just in front of the in-ground pool, which you can see in the background.  I was kind of worried about what would happen if the minister took a step back.  The wedding was short, and the food afterward was plentiful.

A zoomed out view, so you can see the tables set up.  On the right side are the porch and garage, and you can just see the Master Bedroom extension of the house poking out on the left--well, more specifically, the gutter attached to that extension.  The tables were lined up in between, and the wedding procession walked down the aisle in between.

The hummingbird feeder, and its attendant hummingbirds.  The birds were quite disappointed when it was removed for the wedding.  You could see them wandering around in confusion, looking for their meal.

The next day, Rebekah and her husband went to honeymoon in New Orleans.  My wife and mother drove them down, and spent the day there.  I stayed in St. Francisville and babysat my two nieces.  They're old enough that if you give them an iPad or Kindle Fire, they'll be nice and quiet for a good while.  I think we all had more fun this way.

Wednesday, September 26, 2012

What's on the back of the envelope?

The name of this blog is "Back of the Envelope".  One of my earliest blog posts was a long explanation about why I named the blog that.  The short version, from that post, can be summed up quickly:
The expression is common enough, but if you're not familiar with it, a back of the envelope calculation is a quick, simple calculation done as an estimate. It's called "back of the envelope" because it can be written out on a small sheet of paper . . . When I first applied for this address on blogspot, the idea was to name the blog after myself . . . Nothing really felt right, though, so I started thinking of other names, a name appropriate for an engineer writing about things he was distinctly unqualified to discuss. It took surprisingly little time to come up with "Back of the Envelope."
I've always used the image of an envelope with something written on the back as the symbol of this site.  In fact, this is the one I had for a long time:
The old back of the envelope symbol.
With the new template, I wanted to change the design while keeping the concept.  The new design is the background of this page.  Unfortunately, since I used the full size of the background that Blogger recommends (1800x1600 pixels, or close to it), you probably can't see the whole thing unless you have a super-high resolution display, even without the blog contents covering it.  So here's the full image, at a reduced resolution:
The new background.
As you can see, the central equation is the same.  This is the bra-ket notation used in quantum physics, and shows the inner product between two quantum computation values, 0 and + (which is a superposition of 0 and 1), so the overlap of 0 and + (technically it's the inner product, but it's the degree to which the two are the same) is one over the square-root of two.

What about the rest of the calculations?  Are they legitimate, or just random doodlings?  They're all legitimate, and equations I've used before, though it's been years.  Hopefully there aren't any mistakes.

The next equation, in red at the top, is just a circle divided into six parts, with one part divided in half.  The equation calculates the area of that section, but it's mainly an excuse for me to estimate pi as three.  That's a common estimate to use for pi when you're just doing a back of the envelope calculation.  Another useful estimate is 5 dB, or the square-root of 10.

On the left side is a charged particle over a ground plane.  This results in an image in the ground plane.  The charge in the ground plane responds in such a way that it's equivalent to an equal and opposite charge reflecting the placement of the first charge.  This results in the equation below, which is also the equation for the potential for a charge dipole.  Charge dipoles consist of equal and opposite charges close together, so that they minimize each other's effects.  A ground plane effectively converts a charge into a charge dipole, which is why ground planes help reduce noise coming from the circuits they're placed under (they also tend to minimize noise coupling into the circuit).

Below that, at the bottom of the page, is the time-invariant form of Schrodinger's Equation, since I figured I needed that on the back of the envelope.

On the right side is a 3-bit Gray code.  This is a binary sequence where only a single bit changes for each step of the sequence.  This was originally used as a method of binary counting for mechanical switches. Since mechanical switches don't change instantaneously, switching from 011 to 100 (3 to 4 in binary), could result in spurious outputs as each switch changes at a different time.  By making it equal the change from 010 to 110 instead, there are no spurious values between them.  In modern digital computers, this particular reason is not as relevant, but it is still useful for error correction.  A Gray code can be visualized as a cube, shown above, where each step travels along the edge of the cube.  I included the cube, with convenient arrows, mainly to give people a clue that I was doing a Gray code, rather than let them think I was trying to count in binary and getting it wrong.  I'm not sure whether it worked or not.

So that's everything.  I hope you enjoyed this boring math post.  I also hope I didn't mess up any of these equations.

Saturday, September 22, 2012

Review of Odd Apocalypse by Dean Koontz

I find Dean Koontz's books either hit or miss. Some of them, like Seize the Night and From the Corner of His Eye, are beautiful, well-told stories, with great characters and intriguing premises. Others, such as Breathless, are rambling and inconclusive. It may have an interesting concept, but it never really develops into a story.

Odd Thomas is one of his better series. Odd is a polite young man and sometime fry-cook who sees dead people. The silent, lingering dead come to him for help, and he does his best to do so. He has a few other talents, such as the occasional vision or prophetic dream, and a psychic magnetism that helps him find people that he's looking for, but he'd always say that his best talent is fry cooking.

After the death of his girlfriend, Odd left his hometown of Pico Mundo, where the authorities knew and relied upon his abilities, to find his way in the wider world. He's faced down enemies from the evil to the misguided, from terrorists to the mystic, and he's killed when necessary. Now he's come to the mansion at Roseland, where there are no roses, in the company of Annamarie, a mysterious, pregnant young woman for whom he's the guardian.

All is not well at Roseland. Time is inconsistent there, and someone, maybe everyone there, is involved in something very evil. And that's just how the book starts.

Like all the Odd novels, the book's strength lies in its titular character, a gentle, humble soul whose strong belief in the power of good, and the necessity to fight evil, drives him to take on incredible dangers. As I read books primarily for the characters, and as Odd is a very strong one, I imagine that I'd enjoy pretty much any Odd Thomas novel. Odd's certainly been around a while, but that's given him more maturity, coupled with a certain moroseness, that's given him more depth. Unlike some long lived characters, he hasn't yet played out.

The actual adventure is a little more science fiction than most of what he does, although not as much as Brother Odd. But it's more old school, H. G. Wells science fiction, which I think works better with Odd. It leant the book a stronger air of mystery than a standard terrorism plot, and I certainly enjoyed it.

Overall, it was a good Odd Thomas novel, and I certainly enjoyed it, but if you're looking for answers to the mystery of Annamaria, you're still going to have to wait.

Wednesday, September 19, 2012

Roman Dinner

On Saturday, Kristin and I hosted a Ancient Roman dinner for our friends.  We've done Roman dinners before, as Kristin has discussed in detail on her blog.  Once again, Kristin did most of the cooking, and I did most of the dishes.  Which is not to say I did none of the cooking--I prepared the hydromel (honey water) and sorted lovage seeds, for example.

Ah, lovage seeds.  Roman meals use a number of ingredients which are not easy to get in the New World.  Among them are lovage seeds.  You can buy lovage seeds in the grocery store, but these aren't really lovage seeds--they're either celery seeds or ajwan seeds, which are different plants entirely.  You can't buy food-grade real lovage seeds, but you can buy them for planting.  And if you get organic seeds, they're untreated and edible.  So we ordered some lovage seeds.  However, while they're not treated, the seeds are only 99% pure--you also get a good bit of dirt and twigs in the package.  In addition, you can't be sure that they've been stored properly as a spice should.  So Kristin was kind of reluctant to use the seeds, but I went through them and painstakingly separated a teaspoon-full of seeds from the twigs and dirt, and convinced her to use them in one dish.

Lovage is not the only hard to get Roman spice.  Rue and pennyroyal are, unfortunately, slightly poisonous herbs.  Kristin's eager to try them--after all, if the Romans could eat them, can't we?  But I insisted that we not feed poison to our friends (besides, rue is supposed to be used fresh, not as seeds, and while Kristin has gotten some seeds, she still hasn't planted them), so we substituted dandelion leaves for the rue.  And don't get me started on myrtle berries--our myrtle bush didn't bloom this year.

Still, we managed to produce a very nice three course meal.  For the appetizer, we had flatbread, olives, sheep and goat cheese (the Romans considered cows beasts of burden, not milk or meat animals), and an assortment of olives and salami (which Kristin considers to be pretty close to Roman sausages).

The real work went into this appetizing main course:
Kristin enjoying the main course.
From the bottom to the top, there's squash seasoned with real lovage (the only one we had enough real lovage seed for), pan-seared fish, Indian chapati (a reasonable approximation of Roman flatbread, we understand), highly-seasoned pork belly, and even-more-seasoned parsnips.  Kristin wasn't too happy with the parsnips, thinking they were too salty, but they turned out to be a favorite, and the only thing we ran out of.  There are also two bottles, one containing conditum paradoxum, and the other containing the hydromel which I made.

The dessert course consisted of honeyed fritters, grapes, and figs.

Most of the recipes came from Sally Grainger's Cooking Apicius (shown left), which is our favorite of the various Roman recipe books.  For one, it's the most modern, and has the best understanding of what ingredients are available to a modern kitchen.  For another, there's a lot of scholarship involved, a lot of it based on the work that went into her and her husband's new translation of Apicius (the most extensive of the Ancient Roman cookbooks).  It seems to us to be pretty accurate, and Kristin thinks it agrees very well with her research in the area.

We did use a somewhat different recipe for the conditum paradoxum, but I've discussed that in detail before.  The hydromel also came from a different source, namely Mark Grant's Roman Cookery (shown right).  The original recipe comes not from Apicius, but from Bassus's Country Matters.  It mixes one part apple juice, two parts honey, and three parts water.  In Grant's recipe, these are boiled rather than aged the way they were in Ancient Rome.  We used apple cider rather than apple juice, since the cider's closer to what the Romans would have had.  The cookbook recommends chilling and serving as an apertif, but I preferred something that could be drunk with a meal.  It was too sweet to drink straight in quantity, but we mixed the hydromel with three parts water, as we had done with the conditum paradoxum.  Unfortunately, this was still too sweet.  Kristin, who's a much better cook than I am, suggested adding some vinegar.  Adding one-and-a-half teaspoons of apple cider vinegar to a serving was just what was needed.  It tastes more of apples that way, and the acid of the vinegar prevents the sweetness from being overwhelming.  Since the Romans usually let the mixture age long enough to ferment, I figure that the result is probably pretty close to what the Romans drank.  According to my calculations, adding one-and-a-half teaspoons of apple cider vinegar to a serving results in a ratio of 1 part apple cider vinegar, 2 parts apple cider, 4 parts honey, and 6 parts water, but Kristin prefers 50% more vinegar, for a stronger acidity.  If I make it again, I'll use my proportions.  It's easier to add a little vinegar later than to take it out.

Saturday, September 15, 2012

Review of The Hollow City by Dan Wells

I loved Dan Wells's I am not a Serial Killer series, so when I saw that he had a new book out in the same genre, I snapped it up.  The Hollow City is not a sequel, and John Cleaver, the heroic sociopath from the I am not a Serial Killer series, does not make an appearance.  It's not even clear that this takes place in the same mythos as his previous books, although it's quite possible, as all these stories take place in our world, though with something sinister lurking beneath the surface.

The hero of this new novel is one Michael Shipman, and like John Cleaver, he has problems.  Rather than the sociopathy of John, Michael suffers from paranoid schizophrenia.  Not only does he have delusions of persecution, he sees people and things that aren't there.  The problem comes when some of the things he sees really are there, and don't go away with the drugs.

The story starts with Michael waking up in the hospital, missing two weeks of memory, with only vague recollections of a hollow city, though he has no idea what that even means.  He's soon committed to a mental hospital, where he's treated for his condition, and starts to realize that much of what he believes about his life simply is not true, but is a product of his schizophrenia.  Meanwhile, the FBI is questioning him about his activities during that missing part of his life, hoping that he can lead them to the Red Line Killer, the serial killer who has been murdering members of the Children of the Earth cult.  The same cult that kidnapped his mother before he was born.  He must learn whether the Children of the Earth are after him, and who are the mysterious Faceless Men, who only he can see, even when his drugs are effective.

It's a powerful premise, and there's a lot to recommend this book, but I kept stumbling over the primary problem with a story told from Michael's POV: that of the unreliable narrator.  Because Michael cannot distinguish what's real and what isn't, the reader is likewise in the dark.  He can guess at whether someone's real, and he'll find himself playing that game constantly (Is the FBI real, how about Michael's girlfriend?  Or the reporter?).  When Michael's suffering from full-blown paranoia it's more obvious than when he's largely in control.  I realize that this is part of the premise, but I found that I just didn't have that much tolerance for an unreliable narrator.

It also takes a little while for the book to get going.  I didn't find the scenes of Michael in the mental hospital, arguing with his doctor and trying to figure out what's real and not, that entertaining.  But once he was moving, and making his way back to the hollow city, then the story picked up, and moved rapidly to a strong conclusion.  I just wish it didn't take as long to get there.

Ultimately, I liked The Hollow City okay, but it is  nowhere near as strong as Dan Wells's John Cleaver novels.

Wednesday, September 12, 2012

Long webpages

This is an issue I've been thinking about some, especially in the context of stories on the web.  How long of a webpage is too long?  When you see a wall of text, do your eyes glaze over?  Do you hit the back button and find something else to read? What if you want to post a long article or story on the web?  How do you go about doing it?

One issue is that long webpages are intimidating.  You watch the little scrollbar shrink to invisibility, and think that maybe it's not worth it.  Then again, if you decide you do want to read a long story, can you do it in one sitting?  Probably not.  But if you go away and come back, how do you find your place again?

One option is to split it up into a number of pages.  More than one blogpost, or an article that spans multiple pages.  This may work, but a lot depends on the software you're using, and how easily you can do it.  Once you have multiple pages, you need to put some effort into making it easy to get from page to page.  How many pages are there?  If there are three, it should be relatively easy to find your way and come back to where you left off.  If there are 20 or so, you might become lost, and forget where you left off.

If instead you keep it all on one long page, you run into the issue of losing your place, especially if you navigate away and then come back.  You can simplify that with headings, but it's still a pain to scroll down to the correct heading, and you may miss it and scroll right past.  Fortunately, webpages can include anchors, which allow you to hyperlink to certain parts of a webpage, including from in the same page, such as I did in my Brief History page.  Unfortunately, the blogging software doesn't always handle anchors that well.  It took some effort to get that page working right (including modifying the html and not switching to the WYSIWYG view, which allows Blogger to mess it up).

In either case, navigation is key.  If you're using multiple pages, then you need to link to both the previous and the next page at both the top and the bottom of the page (you need to be able to go back from the top and forward from the bottom, but it also helps to be able to go forward or backward a page at a time to find your place without needing to scroll to the top or bottom each time).  You should also have links either to all of the pages, or to a table of contents.  If you're using one long page, you need to have periodic links to the table of contents on the same page.  This could alternatively be done with a separate frame that displays the table of contents at all times, but that requires you to muck around with the html of the page.  Blogging software generally can't handle that for you.

So, you see, there are a lot of issues involved in getting really long posts to work. I'd be happy to take suggestions for any other tricks.

Saturday, September 08, 2012

Update to blog

I've been ignoring all the little improvements that Google has been making to Blogger for a while now. But recently I decided that it was time to finally update to a more recent template. It was a pain, because I'd already done a good bit of customization, and converting it to the new version killed a lot of that customization, and I had to redo it. That took several hours. The end result of all that work looks pretty good, I think, with a custom background, and a standard template that I've updated with some blocks of text.

Overall, I'm happy with how it's turned out.

New Kindles

Amazon has announced its new Kindles, including three new Kindle Fires, and two new e-ink Kindles.  I'm not going to review them here, just talk about their announced features.

New Kindle Fires

The two highest end Kindles have an 8.9" screen, and are priced to compete with tablets like the iPad.  They're cheaper, but have a smaller screen and a dual-core, rather than quad-core, processor.  Amazon must be betting that the budget conscious will compare the two options and decide that the Fire better fits their needs.  I suspect folks are more likely to pick an older iPad, but we'll see.

The new Fire at the low end, the Kindle Fire HD, is a less ambitious follow-on to the original Kindle Fire, having approximately the same size and price as the original.  But it still fulfills my wishlist of improvements.  Aside from the standard next generation upgrades, such as improved processor (marginal upgrade from OMAP 4430 to OMAP 4460, both dual-core), memory (doubled to quadrupled), and screen resolution (upgraded from 1024x600 to 1280x800, enough to support 720 HD), it also has almost all the things I've been missing in the original Kindle Fire.

First and foremost, they've fixed the sound.  This was a significant issue in the first Kindle Fire, which only had two tinny speakers located at the top of the tablet.  Which really made no sense, since when you're watching video (which is the only time when I really need the sound), you hold the Kindle sideways. So the stereo speakers Amazon advertises are both on the left side of the Kindle while watching a movie.  Not to mention that even at full volume, I couldn't hear them over the air conditioning in the bedroom.  I usually just wore headphones when watching video, but it'd have been nice to have the option of using the speakers.  This time, Amazon went out of the way to fix the sound, so the new Kindle Fire has dual-driver stereo speakers on both sides of the Fire when you're holding it sideways to watch a movie, and they make a big deal about how loud and clear it is.  If it's as good as advertised, that fixes a major problem of the original Fire.

Second, they've added a micro-HDMI port.  This was one of my gripes about the Fire, as I'd like to display its content on my television but I was unable to.  I'm glad that they've fixed this.

Third, they've improved battery life, now claiming 11 hours of continuous use, as opposed to 8.5 hours.  This is significantly closer to my assertion that the Fire needs a full day of use in order to fit in with Amazon's other e-readers, which is closer to where the Fire's positioned than the tablet market.  I'd never really had a problem with battery life, but that's mainly because I've never spent a whole day reading from my Kindle.

Finally, they've added an inward-facing camera. They advertise that this is for use with Skype, but it should be usable for other situations where you need to take a picture of yourself.  The iPad also has an outward facing camera, but for the most part, you aren't going to be using the camera on a tablet to take pictures or video, so it's not really a necessity.  It is nice when you want to show the other person in a video chat something, but I've discovered that most people don't really know how to use that feature.

Unfortunately, they haven't added a microSD card slot, which would have allowed the user to expand the memory.  I would have liked that option.  I'd also have liked seeing an AMOLED screen, as opposed to an LCD, but that's still a new, high-end technology, and Fire's definitely positioned at the budget end.

Anyway, the new Fire HD has enough improvements that I'd seriously consider getting it if my wife would let me.  But she points out that she got me the Kindle Fire for Christmas last year, and she'd be a little insulted if I replaced it after less than a year.  So I'll at least have to wait until January.

New Kindle e-inks

The new kindle e-inks are very different creatures from the Kindle Fire.  They clearly are not tablets, and are not designed to be.  They're e-readers, with e-ink displays that are low energy (giving battery life in the weeks range), easier to read in sunlight, and slow. Going to the next page on an e-ink display can be slower than turning a page in a book, and they often invert when doing so in order to refresh the electronic ink, which I find annoying.  Newer Kindles allow you to turn the refresh off, so the page only refreshes every six turns or so, which is good.

The new Kindle Paperwhite e-readers offer some significant improvements over the old Kindle e-readers.  First, they're touch screens, which is something Amazon introduced in the last generation, but is now making standard.  Second, the contrast is much greater.  Earlier Kindles had a gray background, with black ink, but the Paperwhites have a white background, which make them more attractive and easier to read.  Additionally, they're lit.  I've seen people call them backlit, but that's not really the case.  They use a waveguide over the screen to direct light down to the screen, where it will reflect back up.  This should cause less eye-strain than backlit screen, while providing nice, even lighting over the whole page.  One of my main reasons for getting a Kindle Fire rather than a regular Kindle was so I could read in the dark, so this is a great feature.

So what is it still missing?  Well, I didn't see any indication that the page refresh has been improved, so it doesn't need to invert as often and leaves fewer artifacts, but such a marginal improvement might not be important enough to be advertised.  I'm also still waiting for someone to come out with a color e-ink reader.  It can be done, but I don't think the technology's ready for a commercial device yet.


The difference between the e-ink Kindle and the Kindle Fire is not the price, since they're pretty close on the low end.  They're very different systems.  The Kindle Fire is not just a reader, but a full media player and a capable, if low end, tablet, with a large number of Android apps available.  The e-ink Kindle is an e-reader, and is probably a more comfortable platform for reading--even in the dark, now that it's lit.  You get longer battery life, and free 3G data on the high end models (4G is only available on the most expensive Kindle Fire, and while cheap, is not free).  The e-ink Kindle is just pretty limited on what you can use that 3G for, as it's too slow for much web browsing, and incapable of doing video at all.  But you can download Kindle books to your heart's content.

Overall, though, I think I'd prefer the Kindle Fire HD.

Update (9/9/2012): Here's a hands-on look at the new Kindle Fire HD. (hat tip Instapundit)

Tuesday, September 04, 2012


This past weekend, Kristin and I went to Worldcon 70.  Worldcon is one of the bigger non-profit science fiction conventions, and probably the most important.  Kristin and I usually go to the serious cons: World Fantasy, Readercon, and Boskone.  With the partial exception of Boskone (only partial, since much of the "fun" part was spun off into Arisia), these are cons focused on writing and writers, with a significant portion of those in attendance being writers, editors, agents, or publishers--and often writers hoping to meet editors and publishers and agents.  Worldcon has a lot of that too, but it also has a film festival, filking, and a masquerade (specifically, costuming).

Most importantly, though, Worldcon has the Hugos.  This is probably the most important award in fantasy and science fiction, for the best stories, films, editors, etc. of the year.  This year, my friend Ken Liu won a Hugo for his short story "The Paper Menagerie."  Ken's a great writer, and is one of the biggest names in genre fiction right now.

I spent much of my time at Worldcon attending parties, and hanging out at the Black Gate table.  John O'Neill's a great guy to hang out with, and I'm not just saying this because he's agreed to publish one of my stories.  Although that does help.  I also went to a couple of panels, but fewer than I usually do, I think.  Part of the problem is that Worldcon has so many tracks, as many as a dozen panels at the same time.  I can't possibly go to all of the ones that sound interesting, and when I already have to miss most of the ones that sound interesting at any one time, it doesn't seem such a bad thing to miss them all and instead hang out with John O'Neill, Howard Andrew Jones, Peadar O Guilin, and others.