Tuesday, August 31, 2004

At the end of the tour

Last week, I had a productive week and an interesting weekend. This week, the semester starts in earnest. Tuesday is the first day of the course that I'm taking this semester (Convex and Nonlinear Optimization); next Wednesday is the first day of the matrix computations seminar; and various paper and presentation deadlines are fast approaching. It was a good summer; and now I'm glad it's over and another semester has begun.

Some lists from the summer now past:

  • Beverages of choice:
    • Hong-Kong style coffee + tea -- This drink, which can be served hot or cold, consists of coffee mixed with English breakfast tea. Both the tea and the coffee are quite strong. When I had it, it was served with milk and sugar; it was a very good combination.
    • Pu-erh tea -- I've learned that the name sounds different in Cantonese, more like po li (though I've likely butchered the pronunciation). Pu-erh has a strong, earthy sort of black tea taste. I got brother Rick some for a birthday gift, and he thought it was reminiscent of beet juice. I think he'll appreciate it more with a little practice brewing it... but I'm biased.
    • Dragon well tea -- This is a particularly tasty variety of green tea.
    • Silver needle white tea -- Pu-erh and white tea are at far ends of the tea spectrum, insofar as it makes any sense to talk about a tea spectrum. White tea is light, and must be brewed at a lower temperature and for a longer time than even the green teas. The flavor is subtle.
    • Black coffee -- Of course! Peet's is offering a new special blend, their African Blend, which I quite like.
    • Hot water with lime -- I bought a new bottle of lime juice about a week ago, and can once again make one of my favorite late-evening beverages. This goes well with honey.
    • Red tea (rooibos) -- This is actually made from a type of African bush. It has a strong, mellow sort of flavor.
  • Games and amusements
    • Eraser hurling -- Why are we scouring Iraq for Whiteboard Marker Dusters when we have so many of them here already? Upon hearing the tale of a professor who hurled his eraser at a student snoring in the middle of the class, I was inspired. Suppose I practiced hurling weighted erasers at a target in some very public place, then brought along a basketful of erasers with me to class. Would students remain awake? Could a potato cannon be adapted to make an eraser bazooka? This is, I think, my best idea in this area since Bread Do.
    • Survivor: College Tournament -- The name, I think, says it all. Survivor and the Jeopardy College Tournament both enjoy some popularity; why not combine the two? Yes, eraser hurling would be involved.
    • Embarrassingly parallel parking -- I'm not sure what this would involve. Perhaps a lot full of inexperienced teenage drivers playing musical parking spots? Alas, if the game was really embarrassingly parallel in nature, it probably wouldn't be very exciting.
    • People watching -- Finally, a real amusement.
  • Books I want to read
    • Hackers and Painters (Paul Graham)
    • Programming as if People Mattered (I'm missing the author)
    • The Blue Bear (Lynn Schooler)
    • Black Lamb and Grey Falcon (Rebecca West)
    • In Season (Greg Atkinson)
    • The American Language (H.L. Menken)
    • Chasing the Sea (Tom Bissell)
    • A Year in Provence (Peter Mayle)
    • Walter Rudin's autobiography

Friday, August 27, 2004

Indian Summer

Summer comes late to Berkeley.

Throngs of students bustle or lounge, depending on their ages and attitudes. The sun is bright, the air is warm, and tight, sleeveless t-shirts are the norm. Doors are open, and the scents of food and sounds of laughter waft out. On a porch step, two middle-aged men sip their beers and watch the antics of the dog across the street.

A song drifts from the chancellor's lawn; it's something by The Cranberries, sung a capello. A man sipping coffee narrowly averts a disastrous collision with a young woman who is inexpertly trying to skate while walking her dog. A motorcyclist zooms by, oblivious to the drama on the sidewalk, intent only on crossing the intersection before the light change.

The air stays warm even when the sun sets. The horizon, at first bright with the setting sun, dims in color until night has fallen. The sidewalks stay crowded for a while longer: people meeting people, people getting lost, people experiencing Berkeley for the first time or just getting reacquainted with the streets. At last, quiet falls; I listen to the lingering sounds of traffic and insects and the radio.

Tuesday, August 24, 2004


I have added titles to the template. I've also added titles to the past several entries, though I'm too lazy to go back much farther.

I went out wandering...

Trees at twilight,
Sunlit sent'nels.
Gold on the ocean,
Fog on the hills.

Light the lamps
At ghost of the gloaming
For the walker
Watching still.

Meh. Perhaps I should stick to code. It was a nice walk, though. There's something fascinating about natural things lit from below, whether they're tree branches, water fountains, or faces.

  • Currently drinking: White tea


While describing a train ride, I said We stopped at Coliseum station, and a bunch of Raiders fans boarded. Only a sentence or two later did I think: what we?

Mathematicians use we when writing proofs, even if the proof is not joint work. Supposedly the we in this case refers to the reader who will carefully follow the author's arguments; but I doubt many mathematicians deliberately choose we, any more than we deliberately choose the imperative voice when we write let n be an integer or suppose not. For good or ill, proofs are conventionally written in a particular style, and we is part of the style.

But I formed the we habit long before I started writing proofs. When Mom asked what I'd done during a day of elementary school, I would say we ate lunch; and we had recess... Everyone else in the class was doing the same thing as me, at the same time, sometimes even in cooperation with me. And so I said we.

And now? I stare into space; I went for a walk this evening. But if there is any hint that someone else might be staring into space at the same time, or going for a walk in the same direction, I'll revert to we.

If this seems like a lot of hot wind for a two-letter pronoun, consider the following line from an e-mail I sent during a coffee break this afternoon:

Hack hack hack. Boing boing. Hack. Boing. Um.

The response? Dude. Which is another very interesting word...

Sunday, August 22, 2004

Wolfhounds on wheels

While walking to Safeway, I passed a woman walking a dog in a wheelchair. Yes, the dog was in the wheelchair; the woman was not. This curious canine contraption consisted of a pair of wheels and an axle, on which there was a sort of blue sling to support the dog's hindquarters. There was also a metal crossbar on which the dog could prop its legs, in addition to two crossbars which seemed primarily to be there for structural stability. It was a big dog, about three feet tall at the shoulder and husky as well, so those additional crosspieces were probably necessary.

Does anyone ever do stress analyses for dog wheelchairs? What about stress tests? What factors of safety go into the design? Or are dog wheelchairs only subject to an eyeball analysis? I think there could be business opportunities for designers of high-quality pet wheelchairs -- but perhaps that's just an indication that I've never studied business.

On typing

From a letter by Mark Twain to his brother upon the acquisition of a Remington typewriter (quoted in Faster by James Gleick, p. 117):

I am trying t to get the hang of this new f fangled writing machine ... The machine has several virtues I believe it will print faster than I can write. ... It piles an awful stack of words on one page.

(The typographical errors are copied from Faster, and presumably in turn were copied from the original letter.)


From a letter from Bertrand Russell to the editor of The Observer (12th Jan, 1963, p. 30). Via Yours faithfully, Bertrand Russell (ed. Ray Perkins, Jr.), pp. 406--407.

   Have we all become savage? Why do we turn, inevitably, towards ferocity in dealing with political opponents -- towards maiming or killing or sentencing them to disproportionately long imprisonment?
   I think it is because we live in an atmosphere of fear bred by present political policies. We have been conditioned to accept cruelty, even the threat of extermination, as the sole means of defending a way of life that seems to prove itself, by such a result, hardly worth defending.

Wednesday, August 18, 2004


The best thing about dinner at Cancun Taqueria this evening? Mango salsa. We ran out of chips before we ran out of salsa, so I drank the rest without chips.

They have pretty good agua fresca, too, with bits of fruit floating in it.

  • Currently drinking: Cold water. But maybe I'll have hot water and lime soon.

A Specious Odyssey

I've got a great idea for a movie. I call it Y2K+1. In it, a maintenance programmer discovers a mysterious monolithic code of unknown origin. I haven't worked out the details, but I have a few lines of dialogue...

  • What does this code do? It's origin and purpose are a total mystery
  • The editor is opening. I can see the C code. My god, it's full of stars!
  • Just what do you think it's doing, Dave?
  • The 9K series is the most reliable computer program ever made.

On hash function security

Researchers have found flaws in the MD5 and SHA0 hash functions. A hash function is a function which takes a large amount of data (a document, say) and from it generates a much smaller number. Ideally, it should be very hard to find a collision, or two inputs which generate the same output. The recently-discovered flaws in MD5 and SHA0 mean that it's possible to find collisions in these functions much more quickly than anyone had previously realized.

Cryptographically secure hash functions are key to generating digital signatures. To digitally sign a document D, I would compute a hash function H(D), then compute another function S(H(D), K) based on my secret key K. Only I can easily evaluate S, but anyone can check to see that what I've evaluated is correct. We evaluate S(H(D), K) instead of S(D, K) because the output of S is the same size as the input, and we don't want a signature that takes as much space as the original document. Also, we can compute S much more quickly if the input is small. However, we don't want it to be easy for someone to cut our signature and attach it to another document, which they could do if the fake document F had the same hash as D does (i.e. H(D) = H(F)). That's why finding these collisions is considered a big deal.

However, the sky is not falling (except insofar as the sky is always falling locally in areas where convection cycles in the atmosphere produce a downdraft). If I can come up with an input file that produces the same MD5 hash as the mortgage you digitally signed, then I could replace your mortgage with my file, and the signature would still check. But finding some input file that produces the same MD5 hash as your mortgage is a far cry from finding some meaningful input file that produces the same MD5 hash as your mortgage. For the time being, the easiest way to forge an electronic signature on a document in which you will me all your money is to hire goons to steal your key.

  • Currently drinking: Black coffee (Peet's African blend)
  • Current password: Squeamish ossifrage

Tuesday, August 17, 2004

Ink in the drink

I have two fountain pens in Berkeley. One of them takes Parker ink cartridges; the other takes Waterman cartridges, or uses an adaptor to take ink from a bottle. It is a corrolary to Murphy's law that if I can't find one of the pens, I will be out of ink for the other. This evening, Murphy did not strike. I found Waterman cartridges, and had the appropriate pen close at hand. I had no problem taking out the old cartridge, putting the new one in, or reassembling the pen.

I should have been worried. Murphy always gets his due.

Half an hour later, I had an envelope with holes scratched into it, ink stains along my index fingers, a bottle cap full of inky water, and a renewed appreciation of water-soluble inks. I haven't left so many finger prints on a paper since the last time I spilled coffee on my hand while juggling a clipboard.

Just as my pens sometimes run dry, so do my creative juices. At least, so went my thought as I cleaned up and tried to figure out what I wanted to write with my newly-charged pen. Perhaps pouring a little water in my ear would help? Right -- and if the eyes are windows to the soul, then the virtuous should buy stock in eyeball squeegies?

  • Currently drinking: Black tea flavored with osymanthus flowers and water-soluble ink

Saturday, August 14, 2004

Thinking time

A few years ago, I bought a copy of James Gleick's Faster: The Acceleration of Just About Everything. I enjoyed his Chaos: The Making of a New Science when I was in high school, and the title tickled my fancy. I enjoyed it enough that I took it home for my parents to read. I spent part of yesterday evening browsing through the shelves around my old room, saw that Faster was still there, and picked it up. I think I might take it back to California with me.

There's a semi-humorous You might be a graduate student if... list that used to occasionally make it into my inbox. It was funnier before I passed through the 20th grade. One of the bullets is you find the bibliographies of books more interesting than the actual text. I don't feel exactly that way, but besides the re-read value, a strong reason for bringing Faster back to Berkeley with me is for the references, both in the Acknowledgements and Notes section and in the body of the text. More book recommendations!

(I've barely scratched the list of books recommended from reading From Dawn to Decadence, but since when has that factored into my reading habits?)

Vacations are a good time to think about time. What does mail have over e-mail? I've mentioned the aesthetics of pen and paper before. But I think another attraction of hand-written letters is the time they take, both in the drafting and in the sending.

I can type faster than I write, faster even than I can draft a coherent sentence. So when I type, my hand has the tendency to run ahead of me; then I backspace; and then my fingers run ahead again. The mental image I have is of a man walking a crazed little dog -- the type that runs in circles and yips impatiently at the staid pace of its owner. That's an exaggeration, but it captures the feeling. It's a sort of fidget. When I write with pen and paper, or with pencil and paper, I have much less difficulty keeping up my hands in sync with my thoughts. Furthermore, I often write letters in parts; a paragraph or two one day, a few more the next. I rarely write e-mail that way.

Then there's the sending. Write an e-mail, hit send, and you can expect the message to arrive in a matter of minutes. Write a letter, drop it in the mailbox, and you can expect it to arrive in a few days. And that's fast! One of the themes running through Patrick O'Brian's books, which are set in the British Navy early in the nineteenth century, is the sending and receiving of mail. A letter sent could take months to arrive at its destination, if it arrived at all. A correspondence in which there are months of delay between exchanges must be different from a correspondence in which the delay is a minute, an hour, even a day. Minutes are a matter of short term memory; months are not.

Have you noticed how much shorter pop music pieces are than classical or jazz pieces? Or how instantly identifiable BBC segments are by the relatively long periods of time the camera remains in one place? How differently people talk on cell phones than on land lines? How different conversations are when you have only a few minutes to talk over the phone rather than a couple hours to talk over food (or over books, as the case may be)?

Fill in the blank: the blank pace of modern life. Hectic, right? There's a very interesting discussion of American perceptions of leisure time in Bowling Alone by Robert Putnam (which came to my parent's home around the same time as Faster; the two books sit together on the shelf). It's not very original to say that Americans scurry a lot; nor is it original to observe that we actually have a lot of spare time, much more than we realize. Unoriginal hardly means unworthy, though. Old topics are good for chewing slowly; and time is a very old topic.

What's the most famous quote of Thoreau? I came to the woods to live deliberately. The word deliberately does not connote slowness so much as unhurried or careful. It's good to spend some time remembering to be deliberate.

I don't want to reject the fast or the slow. I just like being able to think about it, and make choices about what things I find useful and what things I'd rather not have:
Cell-phone? Not yet.
E-mail? Is great.
Long letters? Also great.
Staccato sentence fragments? Check.

  • Currently drinking: Green tea

Thursday, August 12, 2004

I am at my family's home, and have been here since last Wednesday. Winnie came along for the first week, and we trooped around College Park and DC and Annapolis. My siblings came along for some of the DC visits, and we went to Annapolis with my parents. We ate dinner with my friends on Saturday evening, and ate lunch with one of her college friends on Sunday afternoon, and had other meals with varying subsets of my family. The weather was mild and clear through Wednesday morning, when Winnie left. A thunderstorm blew past Wednesday afternoon, and today a more serious storm system started moving past. I'm listening to the sound of rain on the roof as I type. It's a nice sound.

College Park remains much the same as I remember, enough that it was no problem to navigate. There is a Ten Ren Tea House, new since I graduated (though that's five years past, now). I remember a quirky little coffee shop at that corner which no longer seems to be there. They used to have open mike nights periodically. I visited that cafe sometimes, though I always avoided the open mike nights; but I like the idea of a tea house, too. Not that it matters either way, I suppose.

Now I'm just enjoying the quiet of home. Our old grey cat, Misty, is the only survivor from when I still really lived here, but the other cats are willing to be around, even if they're cautious. There are books, of course, and I've been going through a novel or two each day, for the past couple days. They're mostly short, light, and forgettable. An exception, which I picked up in an idle moment in a Barnes and Noble in DC (you knew I would visit a book store some time, right?) is Don Knuth's Things a Computer Scientist Rarely Talks About. I particularly enjoyed lectures 3 and 4, but the whole book was interesting and entertaining, and I'm looking forward to taking it back to California to lend to friends there.

I'm in the middle of a few serial letters. I do enjoy writing to people, assuming that I remember their address and have some inkling that a letter might be welcome. I took home a fountain pen which is one of my favorites for letter-writing, and some pads of regular-sized paper. I like e-mail -- at least, I like it many days when the spam filter is working -- but there's something relaxing to writing a letter that isn't shared in writing an e-mail. Perhaps it's a lack of immediacy. Or maybe it's just that a pen or pencil and a piece of paper are such wonderfully engineered artifacts: simple to use, robust, unlikely to freeze up or lose a connection, unchanging in their fundamental design for a long time.

I've done a little work, sipped a little tea, and spent a lot of time staring into space. I've exchanged awful puns with Dad, and sung silly songs with Mom, and had unhurried conversations with my brothers, and played with the cats. And while I look forward to returning home to California on Monday, for now I'm just enjoying the old home.

Monday, August 02, 2004

Gen mai cha is green tea with toasted rice kernels. Adagio Tea makes a variant which they call gen mai cha pop, in which the rice kernels are toasted for long enough that they pop. The rice gives the tea a nutty flavor that I like. I keep a tin at the office in the top drawer of my desk.

The office is quiet in the evening these days. One of the advantages of being the only person here after hours is that I can listen to the radio -- via the Internet or from my clock radio -- without my earphones. It's like whistling while I work, but without the absent-minded off-key wandering periods when I concentrate.

The radio is nice during tea breaks, too.

  • Currently drinking: gen mai cha

What the programming world really does not need is a debugging tool based on the antics of a troop of monkeys. It would be amusing, though -- give a whole new meaning to tree walk and dangling pointer.

  • Currently drinking: Russian caravan blend

Sunday, August 01, 2004

Surf the web and talk on the phone at the same time! says the announcer on the Comcast commercial. Does this seem rude to anybody else?

Uttered in an introductory programming class:

How do you eat an elephant? Anybody? You cannot eat an elephant all at once. Not even a tiny baby elephant. You must divide and conquer!

Seems like it could go for any number of disciplines. How much gnashing of teeth actually comes from some poor soul trying to gnaw through the skin of an elephant? Even a tiny baby elephant?

Some days I think I should have chosen a different career path. Like being a zookeeper.